AAA-ATPases in Protein Degradation.

PubMed

Yedidi, Ravikiran S; Wendler, Petra; Enenkel, Cordula

2017-01-01

Proteolytic machineries containing multisubunit protease complexes and AAA-ATPases play a key role in protein quality control and the regulation of protein homeostasis. In these protein degradation machineries, the proteolytically active sites are formed by either threonines or serines which are buried inside interior cavities of cylinder-shaped complexes. In eukaryotic cells, the proteasome is the most prominent protease complex harboring AAA-ATPases. To degrade protein substrates, the gates of the axial entry ports of the protease need to be open. Gate opening is accomplished by AAA-ATPases, which form a hexameric ring flanking the entry ports of the protease. Protein substrates with unstructured domains can loop into the entry ports without the assistance of AAA-ATPases. However, folded proteins require the action of AAA-ATPases to unveil an unstructured terminus or domain. Cycles of ATP binding/hydrolysis fuel the unfolding of protein substrates which are gripped by loops lining up the central pore of the AAA-ATPase ring. The AAA-ATPases pull on the unfolded polypeptide chain for translocation into the proteolytic cavity of the protease. Conformational changes within the AAA-ATPase ring and the adjacent protease chamber create a peristaltic movement for substrate degradation. The review focuses on new technologies toward the understanding of the function and structure of AAA-ATPases to achieve substrate recognition, unfolding and translocation into proteasomes in yeast and mammalian cells and into proteasome-equivalent proteases in bacteria and archaea.

Structure of the active form of human origin recognition complex and its ATPase motor module

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tocilj, Ante; On, Kin Fan; Yuan, Zuanning

Binding of the Origin Recognition Complex (ORC) to origins of replication marks the first step in the initiation of replication of the genome in all eukaryotic cells. Here, we report the structure of the active form of human ORC determined by X-ray crystallography and cryo-electron microscopy. The complex is composed of an ORC1/4/5 motor module lobe in an organization reminiscent of the DNA polymerase clamp loader complexes. A second lobe contains the ORC2/3 subunits. The complex is organized as a double-layered shallow corkscrew, with the AAA+ and AAA+-like domains forming one layer, and the winged-helix domains (WHDs) forming a topmore » layer. CDC6 fits easily between ORC1 and ORC2, completing the ring and the DNA-binding channel, forming an additional ATP hydrolysis site. Analysis of the ATPase activity of the complex provides a basis for understanding ORC activity as well as molecular defects observed in Meier-Gorlin Syndrome mutations.« less

A Non-Competitive Inhibitor of VCP/p97 and VPS4 Reveals Conserved Allosteric Circuits in Type I and II AAA ATPases.

PubMed

Pöhler, Robert; Krahn, Jan H; van den Boom, Johannes; Dobrynin, Grzegorz; Kaschani, Farnusch; Eggenweiler, Hans-Michael; Zenke, Frank T; Kaiser, Markus; Meyer, Hemmo

2018-02-05

AAA ATPases have pivotal functions in diverse cellular processes essential for survival and proliferation. Revealing strategies for chemical inhibition of this class of enzymes is therefore of great interest for the development of novel chemotherapies or chemical tools. Here, we characterize the compound MSC1094308 as a reversible, allosteric inhibitor of the type II AAA ATPase human ubiquitin-directed unfoldase (VCP)/p97 and the type I AAA ATPase VPS4B. Subsequent proteomic, genetic and biochemical studies indicate that MSC1094308 binds to a previously characterized drugable hotspot of p97, thereby inhibiting the D2 ATPase activity. Our results furthermore indicate that a similar allosteric site exists in VPS4B, suggesting conserved allosteric circuits and drugable sites in both type I and II AAA ATPases. Our results may thus guide future chemical tool and drug discovery efforts for the biomedically relevant AAA ATPases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ubiquitin-Like Proteasome System Represents a Eukaryotic-Like Pathway for Targeted Proteolysis in Archaea

DOE PAGES

Fu, Xian; Liu, Rui; Sanchez, Iona; ...

2016-05-17

The molecular mechanisms of targeted proteolysis in archaea are poorly understood, yet they may have deep evolutionary roots shared with the ubiquitin-proteasome system of eukaryotic cells. Here, we demonstrate in archaea that TBP2, a TATA-binding protein (TBP) modified by ubiquitin-like isopeptide bonds, is phosphorylated and targeted for degradation by proteasomes. Rapid turnover of TBP2 required the functions of UbaA (the E1/MoeB/ThiF homolog of archaea), AAA ATPases (Cdc48/p97 and Rpt types), a type 2 JAB1/MPN/MOV34 metalloenzyme (JAMM/MPN+) homolog (JAMM2), and 20S proteasomes. The ubiquitin-like protein modifier small archaeal modifier protein 2 (SAMP2) stimulated the degradation of TBP2, but SAMP2 itself wasmore » not degraded. Analysis of the TBP2 fractions that were not modified by ubiquitin-like linkages revealed that TBP2 had multiple N termini, including Met1-Ser2, Ser2, and Met1-Ser2(p) [where (p) represents phosphorylation]. The evidence suggested that the Met1-Ser2(p) form accumulated in cells that were unable to degrade TBP2. We propose a model in archaea in which the attachment of ubiquitin-like tags can target proteins for degradation by proteasomes and be controlled by N-terminal degrons. In support of a proteolytic mechanism that is energy dependent and recycles the ubiquitin-like protein tags, we find that a network of AAA ATPases and a JAMM/MPN+ metalloprotease are required, in addition to 20S proteasomes, for controlled intracellular proteolysis. IMPORTANCEThis study advances the fundamental knowledge of signal-guided proteolysis in archaea and sheds light on components that are related to the ubiquitin-proteasome system of eukaryotes. In archaea, the ubiquitin-like proteasome system is found to require function of an E1/MoeB/ThiF homolog, a type 2 JAMM/MPN+ metalloprotease, and a network of AAA ATPases for the targeted destruction of proteins. We provide evidence that the attachment of the ubiquitin-like protein is controlled by an N-terminal degron and stimulates proteasome-mediated proteolysis.« less

Mutant Analysis Reveals Allosteric Regulation of ClpB Disaggregase

PubMed Central

Franke, Kamila B.; Bukau, Bernd; Mogk, Axel

2017-01-01

The members of the hexameric AAA+ disaggregase of E. coli and S. cerevisiae, ClpB, and Hsp104, cooperate with the Hsp70 chaperone system in the solubilization of aggregated proteins. Aggregate solubilization relies on a substrate threading activity of ClpB/Hsp104 fueled by ATP hydrolysis in both ATPase rings (AAA-1, AAA-2). ClpB/Hsp104 ATPase activity is controlled by the M-domains, which associate to the AAA-1 ring to downregulate ATP hydrolysis. Keeping M-domains displaced from the AAA-1 ring by association with Hsp70 increases ATPase activity due to enhanced communication between protomers. This communication involves conserved arginine fingers. The control of ClpB/Hsp104 activity is crucial, as hyperactive mutants with permanently dissociated M-domains exhibit cellular toxicity. Here, we analyzed AAA-1 inter-ring communication in relation to the M-domain mediated ATPase regulation, by subjecting a conserved residue of the AAA-1 domain subunit interface of ClpB (A328) to mutational analysis. While all A328X mutants have reduced disaggregation activities, their ATPase activities strongly differed. ClpB-A328I/L mutants have reduced ATPase activity and when combined with the hyperactive ClpB-K476C M-domain mutation, suppress cellular toxicity. This underlines that ClpB ATPase activation by M-domain dissociation relies on increased subunit communication. The ClpB-A328V mutant in contrast has very high ATPase activity and exhibits cellular toxicity on its own, qualifying it as novel hyperactive ClpB mutant. ClpB-A328V hyperactivity is however, different from that of M-domain mutants as M-domains stay associated with the AAA-1 ring. The high ATPase activity of ClpB-A328V primarily relies on the AAA-2 ring and correlates with distinct conformational changes in the AAA-2 catalytic site. These findings characterize the subunit interface residue A328 as crucial regulatory element to control ATP hydrolysis in both AAA rings. PMID:28275610

Structural Insights into the Unusually Strong ATPase Activity of the AAA Domain of the Caenorhabditis elegans Fidgetin-like 1 (FIGL-1) Protein*

PubMed Central

Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

2013-01-01

The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function. PMID:23979136

Structural insights into the unusually strong ATPase activity of the AAA domain of the Caenorhabditis elegans fidgetin-like 1 (FIGL-1) protein.

PubMed

Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

2013-10-11

The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function.

Essential function of VCP/p97 in infection cycle of the nucleopolyhedrovirus AcMNPV in Spodoptera frugiperda Sf9 cells.

PubMed

Lyupina, Yulia V; Erokhov, Pavel A; Kravchuk, Oksana I; Finoshin, Alexander D; Abaturova, Svetlana B; Orlova, Olga V; Beljelarskaya, Svetlana N; Kostyuchenko, Margarita V; Mikhailov, Victor S

2018-06-08

The protein VCP/p97 (also named CDC48 and TER94) belongs to a type II subfamily of the AAA+ATPases and controls cellular proteostasis by acting upstream of proteasomes in the ubiquitin-proteasome protein degradation pathway. The function of VCP/p97 in the baculovirus infection cycle in insect cells remains unknown. Here, we identified VCP/p97 in the fall armyworm Spodoptera frugiperda (Sf9) cells and analyzed the replication of the Autographa californica multiple nucleopolyhedrovirus, AcMNPV, in Sf9 cells in which the VCP/p97 function was inhibited. The specific allosteric inhibitor of the VCP/p97 ATPase activity, NMS-873, did not deplete VCP/p97 in infected cells but caused a dose-dependent inhibition of viral DNA synthesis and efficiently suppressed expression of viral proteins and production of budded virions. NMS-873 caused accumulation of ubiquitinated proteins in a manner similar to the inhibitor of proteasome activity, Bortezomib. This suggests the essential function of VCP/p97 in the baculovirus infection cycle might be associated, at least in part, with the ubiquitin-proteasome system. Copyright © 2018 Elsevier B.V. All rights reserved.

Structure of the active form of human origin recognition complex and its ATPase motor module

PubMed Central

Tocilj, Ante; On, Kin Fan; Yuan, Zuanning; Sun, Jingchuan; Elkayam, Elad; Li, Huilin; Stillman, Bruce; Joshua-Tor, Leemor

2017-01-01

Binding of the Origin Recognition Complex (ORC) to origins of replication marks the first step in the initiation of replication of the genome in all eukaryotic cells. Here, we report the structure of the active form of human ORC determined by X-ray crystallography and cryo-electron microscopy. The complex is composed of an ORC1/4/5 motor module lobe in an organization reminiscent of the DNA polymerase clamp loader complexes. A second lobe contains the ORC2/3 subunits. The complex is organized as a double-layered shallow corkscrew, with the AAA+ and AAA+-like domains forming one layer, and the winged-helix domains (WHDs) forming a top layer. CDC6 fits easily between ORC1 and ORC2, completing the ring and the DNA-binding channel, forming an additional ATP hydrolysis site. Analysis of the ATPase activity of the complex provides a basis for understanding ORC activity as well as molecular defects observed in Meier-Gorlin Syndrome mutations. DOI: http://dx.doi.org/10.7554/eLife.20818.001 PMID:28112645

A conserved inter-domain communication mechanism regulates the ATPase activity of the AAA-protein Drg1.

PubMed

Prattes, Michael; Loibl, Mathias; Zisser, Gertrude; Luschnig, Daniel; Kappel, Lisa; Rössler, Ingrid; Grassegger, Manuela; Hromic, Altijana; Krieger, Elmar; Gruber, Karl; Pertschy, Brigitte; Bergler, Helmut

2017-03-17

AAA-ATPases fulfil essential roles in different cellular pathways and often act in form of hexameric complexes. Interaction with pathway-specific substrate and adaptor proteins recruits them to their targets and modulates their catalytic activity. This substrate dependent regulation of ATP hydrolysis in the AAA-domains is mediated by a non-catalytic N-terminal domain. The exact mechanisms that transmit the signal from the N-domain and coordinate the individual AAA-domains in the hexameric complex are still the topic of intensive research. Here, we present the characterization of a novel mutant variant of the eukaryotic AAA-ATPase Drg1 that shows dysregulation of ATPase activity and altered interaction with Rlp24, its substrate in ribosome biogenesis. This defective regulation is the consequence of amino acid exchanges at the interface between the regulatory N-domain and the adjacent D1 AAA-domain. The effects caused by these mutations strongly resemble those of pathological mutations of the AAA-ATPase p97 which cause the hereditary proteinopathy IBMPFD (inclusion body myopathy associated with Paget's disease of the bone and frontotemporal dementia). Our results therefore suggest well conserved mechanisms of regulation between structurally, but not functionally related members of the AAA-family.

Origin Licensing Requires ATP Binding and Hydrolysis by the MCM Replicative Helicase

PubMed Central

Coster, Gideon; Frigola, Jordi; Beuron, Fabienne; Morris, Edward P.; Diffley, John F.X.

2014-01-01

Summary Loading of the six related Minichromosome Maintenance (MCM) proteins as head-to-head double hexamers during DNA replication origin licensing is crucial for ensuring once-per-cell-cycle DNA replication in eukaryotic cells. Assembly of these prereplicative complexes (pre-RCs) requires the Origin Recognition Complex (ORC), Cdc6, and Cdt1. ORC, Cdc6, and MCM are members of the AAA+ family of ATPases, and pre-RC assembly requires ATP hydrolysis. Here we show that ORC and Cdc6 mutants defective in ATP hydrolysis are competent for origin licensing. However, ATP hydrolysis by Cdc6 is required to release nonproductive licensing intermediates. We show that ATP binding stabilizes the wild-type MCM hexamer. Moreover, by analyzing MCM containing mutant subunits, we show that ATP binding and hydrolysis by MCM are required for Cdt1 release and double hexamer formation. This work alters our view of how ATP is used by licensing factors to assemble pre-RCs. PMID:25087873

The AAA protein spastin possesses two levels of basal ATPase activity.

PubMed

Fan, Xiangyu; Lin, Zhijie; Fan, Guanghui; Lu, Jing; Hou, Yongfei; Habai, Gulijiazi; Sun, Linyue; Yu, Pengpeng; Shen, Yuequan; Wen, Maorong; Wang, Chunguang

2018-05-01

The AAA ATPase spastin is a microtubule-severing enzyme that plays important roles in various cellular events including axon regeneration. Herein, we found that the basal ATPase activity of spastin is negatively regulated by spastin concentration. By determining a spastin crystal structure, we demonstrate the necessity of intersubunit interactions between spastin AAA domains. Neutralization of the positive charges in the microtubule-binding domain (MTBD) of spastin dramatically decreases the ATPase activity at low concentration, although the ATP-hydrolyzing potential is not affected. These results demonstrate that, in addition to the AAA domain, the MTBD region of spastin is also involved in regulating ATPase activity, making interactions between spastin protomers more complicated than expected. © 2018 Federation of European Biochemical Societies.

CDC-48/p97 coordinates CDT-1 degradation with GINS chromatin dissociation to ensure faithful DNA replication.

PubMed

Franz, André; Orth, Michael; Pirson, Paul A; Sonneville, Remi; Blow, J Julian; Gartner, Anton; Stemmann, Olaf; Hoppe, Thorsten

2011-10-07

Faithful transmission of genomic information requires tight spatiotemporal regulation of DNA replication factors. In the licensing step of DNA replication, CDT-1 is loaded onto chromatin to subsequently promote the recruitment of additional replication factors, including CDC-45 and GINS. During the elongation step, the CDC-45/GINS complex moves with the replication fork; however, it is largely unknown how its chromatin association is regulated. Here, we show that the chaperone-like ATPase CDC-48/p97 coordinates degradation of CDT-1 with release of the CDC-45/GINS complex. C. elegans embryos lacking CDC-48 or its cofactors UFD-1/NPL-4 accumulate CDT-1 on mitotic chromatin, indicating a critical role of CDC-48 in CDT-1 turnover. Strikingly, CDC-48(UFD-1/NPL-4)-deficient embryos show persistent chromatin association of CDC-45/GINS, which is a consequence of CDT-1 stabilization. Moreover, our data confirmed a similar regulation in Xenopus egg extracts, emphasizing a conserved coordination of licensing and elongation events during eukaryotic DNA replication by CDC-48/p97. Copyright © 2011 Elsevier Inc. All rights reserved.

Meiotic Clade AAA ATPases: Protein Polymer Disassembly Machines.

PubMed

Monroe, Nicole; Hill, Christopher P

2016-05-08

Meiotic clade AAA ATPases (ATPases associated with diverse cellular activities), which were initially grouped on the basis of phylogenetic classification of their AAA ATPase cassette, include four relatively well characterized family members, Vps4, spastin, katanin and fidgetin. These enzymes all function to disassemble specific polymeric protein structures, with Vps4 disassembling the ESCRT-III polymers that are central to the many membrane-remodeling activities of the ESCRT (endosomal sorting complexes required for transport) pathway and spastin, katanin p60 and fidgetin affecting multiple aspects of cellular dynamics by severing microtubules. They share a common domain architecture that features an N-terminal MIT (microtubule interacting and trafficking) domain followed by a single AAA ATPase cassette. Meiotic clade AAA ATPases function as hexamers that can cycle between the active assembly and inactive monomers/dimers in a regulated process, and they appear to disassemble their polymeric substrates by translocating subunits through the central pore of their hexameric ring. Recent studies with Vps4 have shown that nucleotide-induced asymmetry is a requirement for substrate binding to the pore loops and that recruitment to the protein lattice via MIT domains also relieves autoinhibition and primes the AAA ATPase cassettes for substrate binding. The most striking, unifying feature of meiotic clade AAA ATPases may be their MIT domain, which is a module that is found in a wide variety of proteins that localize to ESCRT-III polymers. Spastin also displays an adjacent microtubule binding sequence, and the presence of both ESCRT-III and microtubule binding elements may underlie the recent findings that the ESCRT-III disassembly function of Vps4 and the microtubule-severing function of spastin, as well as potentially katanin and fidgetin, are highly coordinated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structural Basis for Disassembly of Katanin Heterododecamers.

PubMed

Nithianantham, Stanley; McNally, Francis J; Al-Bassam, Jawdat

2018-05-11

The reorganization of microtubules in mitosis, meiosis and development requires the microtubule-severing activity of katanin.  Katanin is a heterodimer composed of an ATPase Associated with diverse cellular Activities (AAA) subunit and a regulatory subunit. Microtubule severing requires ATP hydrolysis by katanin's conserved AAA ATPase domains. Whereas other AAA ATPases form stable hexamers, we show that katanin only forms monomer or dimers of heterodimers in solution.  Katanin oligomers consistent with hexamers of heterodimers or heterododecamers were only observed for an ATP hydrolysis deficient mutant in the presence of ATP.  X-ray structures of katanin's AAA ATPase in monomeric nucleotide-free and pseudo-oligomeric ADP-bound states reveal conformational changes in AAA subdomains that explained the structural basis for instability of katanin heterododecamer.  We propose that the rapid dissociation of katanin AAA oligomers may lead to an auto-inhibited state that prevents inappropriate microtubule severing, or that cyclical disassembly into heterodimers may critically contribute to the microtubule-severing mechanism. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Valosin-containing protein VCP/p97 is essential for the intracellular development of Leishmania and its survival under heat stress.

PubMed

Guedes Aguiar, Bruno; Padmanabhan, Prasad K; Dumas, Carole; Papadopoulou, Barbara

2018-06-12

Valosin-containing protein (VCP)/p97/Cdc48 is one of the best-characterised type II cytosolic AAA+ ATPases most known for their role in ubiquitin-dependent protein quality control. Here, we provide functional insights into the role of the Leishmania VCP/p97 homologue (LiVCP) in the parasite intracellular development. We demonstrate that although LiVCP is an essential gene, Leishmania infantum promastigotes can grow with less VCP. In contrast, growth of axenic and intracellular amastigotes is dramatically affected upon decreased LiVCP levels in heterozygous and temperature sensitive (ts) LiVCP mutants or the expression of dominant negative mutants known to specifically target the second conserved VCP ATPase domain, a major contributor of the VCP overall ATPase activity. Interestingly, these VCP mutants are also unable to survive heat stress, and a ts VCP mutant is defective in amastigote growth. Consistent with LiVCP's essential function in amastigotes, LiVCP messenger ribonucleic acid undergoes 3'Untranslated Region (UTR)-mediated developmental regulation, resulting in higher VCP expression in amastigotes. Furthermore, we show that parasite mutant lines expressing lower VCP levels or dominant negative VCP forms exhibit high accumulation of polyubiquitinated proteins and increased sensitivity to proteotoxic stress, supporting the ubiquitin-selective chaperone function of LiVCP. Together, these results emphasise the crucial role LiVCP plays under heat stress and during the parasite intracellular development. © 2018 John Wiley & Sons Ltd.

Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

NASA Astrophysics Data System (ADS)

Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

2014-03-01

Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell.

Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

PubMed Central

Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

2014-01-01

Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. PMID:24658080

Cryo-EM structures of the eukaryotic replicative helicase bound to a translocation substrate

NASA Astrophysics Data System (ADS)

Abid Ali, Ferdos; Renault, Ludovic; Gannon, Julian; Gahlon, Hailey L.; Kotecha, Abhay; Zhou, Jin Chuan; Rueda, David; Costa, Alessandro

2016-02-01

The Cdc45-MCM-GINS (CMG) helicase unwinds DNA during the elongation step of eukaryotic genome duplication and this process depends on the MCM ATPase function. Whether CMG translocation occurs on single- or double-stranded DNA and how ATP hydrolysis drives DNA unwinding remain open questions. Here we use cryo-electron microscopy to describe two subnanometre resolution structures of the CMG helicase trapped on a DNA fork. In the predominant state, the ring-shaped C-terminal ATPase of MCM is compact and contacts single-stranded DNA, via a set of pre-sensor 1 hairpins that spiral around the translocation substrate. In the second state, the ATPase module is relaxed and apparently substrate free, while DNA intimately contacts the downstream amino-terminal tier of the MCM motor ring. These results, supported by single-molecule FRET measurements, lead us to suggest a replication fork unwinding mechanism whereby the N-terminal and AAA+ tiers of the MCM work in concert to translocate on single-stranded DNA.

Analysis of the cooperative ATPase cycle of the AAA+ chaperone ClpB from Thermus thermophilus by using ordered heterohexamers with an alternating subunit arrangement.

PubMed

Yamasaki, Takashi; Oohata, Yukiko; Nakamura, Toshiki; Watanabe, Yo-hei

2015-04-10

The ClpB/Hsp104 chaperone solubilizes and reactivates protein aggregates in cooperation with DnaK/Hsp70 and its cofactors. The ClpB/Hsp104 protomer has two AAA+ modules, AAA-1 and AAA-2, and forms a homohexamer. In the hexamer, these modules form a two-tiered ring in which each tier consists of homotypic AAA+ modules. By ATP binding and its hydrolysis at these AAA+ modules, ClpB/Hsp104 exerts the mechanical power required for protein disaggregation. Although ATPase cycle of this chaperone has been studied by several groups, an integrated understanding of this cycle has not been obtained because of the complexity of the mechanism and differences between species. To improve our understanding of the ATPase cycle, we prepared many ordered heterohexamers of ClpB from Thermus thermophilus, in which two subunits having different mutations were cross-linked to each other and arranged alternately and measured their nucleotide binding, ATP hydrolysis, and disaggregation abilities. The results indicated that the ATPase cycle of ClpB proceeded as follows: (i) the 12 AAA+ modules randomly bound ATP, (ii) the binding of four or more ATP to one AAA+ ring was sensed by a conserved Arg residue and converted another AAA+ ring into the ATPase-active form, and (iii) ATP hydrolysis occurred cooperatively in each ring. We also found that cooperative ATP hydrolysis in at least one ring was needed for the disaggregation activity of ClpB. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Mechanism of Archaeal MCM Helicase Recruitment to DNA Replication Origins

PubMed Central

Samson, Rachel Y.; Abeyrathne, Priyanka D.; Bell, Stephen D.

2015-01-01

Summary Cellular DNA replication origins direct the recruitment of replicative helicases via the action of initiator proteins belonging to the AAA+ superfamily of ATPases. Archaea have a simplified subset of the eukaryotic DNA replication machinery proteins and possess initiators that appear ancestral to both eukaryotic Orc1 and Cdc6. We have reconstituted origin-dependent recruitment of the homohexameric archaeal MCM in vitro with purified recombinant proteins. Using this system, we reveal that archaeal Orc1-1 fulfills both Orc1 and Cdc6 functions by binding to a replication origin and directly recruiting MCM helicase. We identify the interaction interface between these proteins and reveal how ATP binding by Orc1-1 modulates recruitment of MCM. Additionally, we provide evidence that an open-ring form of the archaeal MCM homohexamer is loaded at origins. PMID:26725007

Crystal Structure and Biochemical Characterization of a Mycobacterium smegmatis AAA-Type Nucleoside Triphosphatase Phosphohydrolase (Msm0858).

PubMed

Unciuleac, Mihaela-Carmen; Smith, Paul C; Shuman, Stewart

2016-05-15

AAA proteins (ATPases associated with various cellular activities) use the energy of ATP hydrolysis to drive conformational changes in diverse macromolecular targets. Here, we report the biochemical characterization and 2.5-Å crystal structure of a Mycobacterium smegmatis AAA protein Msm0858, the ortholog of Mycobacterium tuberculosis Rv0435c. Msm0858 is a magnesium-dependent ATPase and is active with all nucleoside triphosphates (NTPs) and deoxynucleoside triphosphates (dNTPs) as substrates. The Msm0858 structure comprises (i) an N-terminal domain (amino acids [aa] 17 to 201) composed of two β-barrel modules and (ii) two AAA domains, D1 (aa 212 to 473) and D2 (aa 476 to 744), each of which has ADP in the active site. Msm0858-ADP is a monomer in solution and in crystallized form. Msm0858 domains are structurally homologous to the corresponding modules of mammalian p97. However, the position of the N-domain modules relative to the AAA domains in the Msm0858-ADP tertiary structure is different and would impede the formation of a p97-like hexameric quaternary structure. Mutational analysis of the A-box and B-box motifs indicated that the D1 and D2 AAA domains are both capable of ATP hydrolysis. Simultaneous mutations of the D1 and D2 active-site motifs were required to abolish ATPase activity. ATPase activity was effaced by mutation of the putative D2 arginine finger, suggesting that Msm0858 might oligomerize during the ATPase reaction cycle. A truncated variant Msm0858 (aa 212 to 745) that lacks the N domain was characterized as a catalytically active homodimer. Recent studies have underscored the importance of AAA proteins (ATPases associated with various cellular activities) in the physiology of mycobacteria. This study reports the ATPase activity and crystal structure of a previously uncharacterized mycobacterial AAA protein, Msm0858. Msm0858 consists of an N-terminal β-barrel domain and two AAA domains, each with ADP bound in the active site. Msm0858 is a structural homolog of mammalian p97, with respect to the linear order and tertiary structures of their domains. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Systematic VCP-UBXD Adaptor Network Proteomics Identifies a Role for UBXN10 in Regulating Ciliogenesis

PubMed Central

Raman, Malavika; Sergeev, Mikhail; Garnaas, Maija; Lydeard, John R.; Huttlin, Edward L.; Goessling, Wolfram; Shah, Jagesh V.; Harper, J. Wade

2015-01-01

The AAA-ATPase VCP (also known as p97 or CDC48) uses ATP hydrolysis to “segregate” ubiquitinated proteins from their binding partners. VCP acts via UBX-domain containing adaptors that provide target specificity, but targets and functions of UBXD proteins remain poorly understood. Through systematic proteomic analysis of UBXD proteins in human cells, we reveal a network of over 195 interacting proteins, implicating VCP in diverse cellular pathways. We have explored one such complex between an unstudied adaptor UBXN10 and the intraflagellar transport B (IFT-B) complex, which regulates anterograde transport into cilia. UBXN10 localizes to cilia in a VCP-dependent manner and both VCP and UBXN10 are required for ciliogenesis. Pharmacological inhibition of VCP destabilized the IFT-B complex and increased trafficking rates. Depletion of UBXN10 in zebrafish embryos causes defects in left-right asymmetry, which depends on functional cilia. This study provides a resource for exploring the landscape of UBXD proteins in biology and identifies an unexpected requirement for VCP-UBXN10 in ciliogenesis. PMID:26389662

Systematic proteomics of the VCP-UBXD adaptor network identifies a role for UBXN10 in regulating ciliogenesis.

PubMed

Raman, Malavika; Sergeev, Mikhail; Garnaas, Maija; Lydeard, John R; Huttlin, Edward L; Goessling, Wolfram; Shah, Jagesh V; Harper, J Wade

2015-10-01

The AAA-ATPase VCP (also known as p97 or CDC48) uses ATP hydrolysis to 'segregate' ubiquitylated proteins from their binding partners. VCP acts through UBX-domain-containing adaptors that provide target specificity, but the targets and functions of UBXD proteins remain poorly understood. Through systematic proteomic analysis of UBXD proteins in human cells, we reveal a network of over 195 interacting proteins, implicating VCP in diverse cellular pathways. We have explored one such complex between an unstudied adaptor UBXN10 and the intraflagellar transport B (IFT-B) complex, which regulates anterograde transport into cilia. UBXN10 localizes to cilia in a VCP-dependent manner and both VCP and UBXN10 are required for ciliogenesis. Pharmacological inhibition of VCP destabilized the IFT-B complex and increased trafficking rates. Depletion of UBXN10 in zebrafish embryos causes defects in left-right asymmetry, which depends on functional cilia. This study provides a resource for exploring the landscape of UBXD proteins in biology and identifies an unexpected requirement for VCP-UBXN10 in ciliogenesis.

Conformational control and DNA-binding mechanism of the metazoan origin recognition complex.

PubMed

Bleichert, Franziska; Leitner, Alexander; Aebersold, Ruedi; Botchan, Michael R; Berger, James M

2018-06-26

In eukaryotes, the heterohexameric origin recognition complex (ORC) coordinates replication onset by facilitating the recruitment and loading of the minichromosome maintenance 2-7 (Mcm2-7) replicative helicase onto DNA to license origins. Drosophila ORC can adopt an autoinhibited configuration that is predicted to prevent Mcm2-7 loading; how the complex is activated and whether other ORC homologs can assume this state are not known. Using chemical cross-linking and mass spectrometry, biochemical assays, and electron microscopy (EM), we show that the autoinhibited state of Drosophila ORC is populated in solution, and that human ORC can also adopt this form. ATP binding to ORC supports a transition from the autoinhibited state to an active configuration, enabling the nucleotide-dependent association of ORC with both DNA and Cdc6. An unstructured N-terminal region adjacent to the conserved ATPase domain of Orc1 is shown to be required for high-affinity ORC-DNA interactions, but not for activation. ORC optimally binds DNA duplexes longer than the predicted footprint of the ORC ATPases associated with a variety of cellular activities (AAA + ) and winged-helix (WH) folds; cryo-EM analysis of Drosophila ORC bound to DNA and Cdc6 indicates that ORC contacts DNA outside of its central core region, bending the DNA away from its central DNA-binding channel. Our findings indicate that ORC autoinhibition may be common to metazoans and that ORC-Cdc6 remodels origin DNA before Mcm2-7 recruitment and loading.

Structural Insights into the Allosteric Operation of the Lon AAA+ Protease.

PubMed

Lin, Chien-Chu; Su, Shih-Chieh; Su, Ming-Yuan; Liang, Pi-Hui; Feng, Chia-Cheng; Wu, Shih-Hsiung; Chang, Chung-I

2016-05-03

The Lon AAA+ protease (LonA) is an evolutionarily conserved protease that couples the ATPase cycle into motion to drive substrate translocation and degradation. A hallmark feature shared by AAA+ proteases is the stimulation of ATPase activity by substrates. Here we report the structure of LonA bound to three ADPs, revealing the first AAA+ protease assembly where the six protomers are arranged alternately in nucleotide-free and bound states. Nucleotide binding induces large coordinated movements of conserved pore loops from two pairs of three non-adjacent protomers and shuttling of the proteolytic groove between the ATPase site and a previously unknown Arg paddle. Structural and biochemical evidence supports the roles of the substrate-bound proteolytic groove in allosteric stimulation of ATPase activity and the conserved Arg paddle in driving substrate degradation. Altogether, this work provides a molecular framework for understanding how ATP-dependent chemomechanical movements drive allosteric processes for substrate degradation in a major protein-destruction machine. Copyright © 2016 Elsevier Ltd. All rights reserved.

Point Mutations in the Stem Region and the Fourth AAA Domain of Cytoplasmic Dynein Heavy Chain Partially Suppress the Phenotype of NUDF/LIS1 Loss in Aspergillus nidulans

PubMed Central

Zhuang, Lei; Zhang, Jun; Xiang, Xin

2007-01-01

Cytoplasmic dynein performs multiple cellular tasks but its regulation remains unclear. The dynein heavy chain has a N-terminal stem that binds to other subunits and a C-terminal motor unit that contains six AAA (ATPase associated with cellular activities) domains and a microtubule-binding site located between AAA4 and AAA5. In Aspergillus nidulans, NUDF (a LIS1 homolog) functions in the dynein pathway, and two nudF6 partial suppressors were mapped to the nudA dynein heavy chain locus. Here we identified these two mutations. The nudAL1098F mutation resides in the stem region, and nudAR3086C is in the end of AAA4. These mutations partially suppress the phenotype of nudF deletion but do not suppress the phenotype exhibited by mutants of dynein intermediate chain and Arp1. Surprisingly, the stronger ΔnudF suppressor, nudAR3086C, causes an obvious decrease in the basal level of dynein's ATPase activity and an increase in dynein's distribution along microtubules. Thus, suppression of the ΔnudF phenotype may result from mechanisms other than simply the enhancement of dynein's ATPase activity. The fact that a mutation in the end of AAA4 negatively regulates dynein's ATPase activity but partially compensates for NUDF loss indicates the importance of the AAA4 domain in dynein regulation in vivo. PMID:17237507

Chromatin-associated degradation is defined by UBXN-3/FAF1 to safeguard DNA replication fork progression.

PubMed

Franz, André; Pirson, Paul A; Pilger, Domenic; Halder, Swagata; Achuthankutty, Divya; Kashkar, Hamid; Ramadan, Kristijan; Hoppe, Thorsten

2016-02-04

The coordinated activity of DNA replication factors is a highly dynamic process that involves ubiquitin-dependent regulation. In this context, the ubiquitin-directed ATPase CDC-48/p97 recently emerged as a key regulator of chromatin-associated degradation in several of the DNA metabolic pathways that assure genome integrity. However, the spatiotemporal control of distinct CDC-48/p97 substrates in the chromatin environment remained unclear. Here, we report that progression of the DNA replication fork is coordinated by UBXN-3/FAF1. UBXN-3/FAF1 binds to the licensing factor CDT-1 and additional ubiquitylated proteins, thus promoting CDC-48/p97-dependent turnover and disassembly of DNA replication factor complexes. Consequently, inactivation of UBXN-3/FAF1 stabilizes CDT-1 and CDC-45/GINS on chromatin, causing severe defects in replication fork dynamics accompanied by pronounced replication stress and eventually resulting in genome instability. Our work identifies a critical substrate selection module of CDC-48/p97 required for chromatin-associated protein degradation in both Caenorhabditis elegans and humans, which is relevant to oncogenesis and aging.

Chromatin-associated degradation is defined by UBXN-3/FAF1 to safeguard DNA replication fork progression

PubMed Central

Franz, André; Pirson, Paul A.; Pilger, Domenic; Halder, Swagata; Achuthankutty, Divya; Kashkar, Hamid; Ramadan, Kristijan; Hoppe, Thorsten

2016-01-01

The coordinated activity of DNA replication factors is a highly dynamic process that involves ubiquitin-dependent regulation. In this context, the ubiquitin-directed ATPase CDC-48/p97 recently emerged as a key regulator of chromatin-associated degradation in several of the DNA metabolic pathways that assure genome integrity. However, the spatiotemporal control of distinct CDC-48/p97 substrates in the chromatin environment remained unclear. Here, we report that progression of the DNA replication fork is coordinated by UBXN-3/FAF1. UBXN-3/FAF1 binds to the licensing factor CDT-1 and additional ubiquitylated proteins, thus promoting CDC-48/p97-dependent turnover and disassembly of DNA replication factor complexes. Consequently, inactivation of UBXN-3/FAF1 stabilizes CDT-1 and CDC-45/GINS on chromatin, causing severe defects in replication fork dynamics accompanied by pronounced replication stress and eventually resulting in genome instability. Our work identifies a critical substrate selection module of CDC-48/p97 required for chromatin-associated protein degradation in both Caenorhabditis elegans and humans, which is relevant to oncogenesis and aging. PMID:26842564

Structure of the eukaryotic replicative CMG helicase suggests a pumpjack motion for translocation

DOE PAGES

Yuan, Zuanning; Bai, Lin; Sun, Jingchuan; ...

2016-02-08

The CMG helicase is composed of Cdc45, Mcm2–7 and GINS. Here we report the structure of the Saccharomyces cerevisiae CMG, determined by cryo-EM at a resolution of 3.7–4.8 Å. The structure reveals that GINS and Cdc45 scaffold the N tier of the helicase while enabling motion of the AAA+ C tier. CMG exists in two alternating conformations, compact and extended, thus suggesting that the helicase moves like an inchworm. The N-terminal regions of Mcm2–7, braced by Cdc45–GINS, form a rigid platform upon which the AAA+ C domains make longitudinal motions, nodding up and down like an oil-rig pumpjack attached tomore » a stable platform. The Mcm ring is remodeled in CMG relative to the inactive Mcm2–7 double hexamer. In addition, the Mcm5 winged-helix domain is inserted into the central channel, thus blocking entry of double-stranded DNA and supporting a steric-exclusion DNA-unwinding model.« less

Fundamental Characteristics of AAA+ Protein Family Structure and Function.

PubMed

Miller, Justin M; Enemark, Eric J

2016-01-01

Many complex cellular events depend on multiprotein complexes known as molecular machines to efficiently couple the energy derived from adenosine triphosphate hydrolysis to the generation of mechanical force. Members of the AAA+ ATPase superfamily (ATPases Associated with various cellular Activities) are critical components of many molecular machines. AAA+ proteins are defined by conserved modules that precisely position the active site elements of two adjacent subunits to catalyze ATP hydrolysis. In many cases, AAA+ proteins form a ring structure that translocates a polymeric substrate through the central channel using specialized loops that project into the central channel. We discuss the major features of AAA+ protein structure and function with an emphasis on pivotal aspects elucidated with archaeal proteins.

Assessing heterogeneity in oligomeric AAA+ machines.

PubMed

Sysoeva, Tatyana A

2017-03-01

ATPases Associated with various cellular Activities (AAA+ ATPases) are molecular motors that use the energy of ATP binding and hydrolysis to remodel their target macromolecules. The majority of these ATPases form ring-shaped hexamers in which the active sites are located at the interfaces between neighboring subunits. Structural changes initiate in an active site and propagate to distant motor parts that interface and reshape the target macromolecules, thereby performing mechanical work. During the functioning cycle, the AAA+ motor transits through multiple distinct states. Ring architecture and placement of the catalytic sites at the intersubunit interfaces allow for a unique level of coordination among subunits of the motor. This in turn results in conformational differences among subunits and overall asymmetry of the motor ring as it functions. To date, a large amount of structural information has been gathered for different AAA+ motors, but even for the most characterized of them only a few structural states are known and the full mechanistic cycle cannot be yet reconstructed. Therefore, the first part of this work will provide a broad overview of what arrangements of AAA+ subunits have been structurally observed focusing on diversity of ATPase oligomeric ensembles and heterogeneity within the ensembles. The second part of this review will concentrate on methods that assess structural and functional heterogeneity among subunits of AAA+ motors, thus bringing us closer to understanding the mechanism of these fascinating molecular motors.

Fundamental Characteristics of AAA+ Protein Family Structure and Function

PubMed Central

2016-01-01

Many complex cellular events depend on multiprotein complexes known as molecular machines to efficiently couple the energy derived from adenosine triphosphate hydrolysis to the generation of mechanical force. Members of the AAA+ ATPase superfamily (ATPases Associated with various cellular Activities) are critical components of many molecular machines. AAA+ proteins are defined by conserved modules that precisely position the active site elements of two adjacent subunits to catalyze ATP hydrolysis. In many cases, AAA+ proteins form a ring structure that translocates a polymeric substrate through the central channel using specialized loops that project into the central channel. We discuss the major features of AAA+ protein structure and function with an emphasis on pivotal aspects elucidated with archaeal proteins. PMID:27703410

Diverged composition and regulation of the Trypanosoma brucei origin recognition complex that mediates DNA replication initiation

PubMed Central

Marques, Catarina A.; Tiengwe, Calvin; Lemgruber, Leandro; Damasceno, Jeziel D.; Scott, Alan; Paape, Daniel; Marcello, Lucio; McCulloch, Richard

2016-01-01

Abstract Initiation of DNA replication depends upon recognition of genomic sites, termed origins, by AAA+ ATPases. In prokaryotes a single factor binds each origin, whereas in eukaryotes this role is played by a six-protein origin recognition complex (ORC). Why eukaryotes evolved a multisubunit initiator, and the roles of each component, remains unclear. In Trypanosoma brucei, an ancient unicellular eukaryote, only one ORC-related initiator, TbORC1/CDC6, has been identified by sequence homology. Here we show that three TbORC1/CDC6-interacting factors also act in T. brucei nuclear DNA replication and demonstrate that TbORC1/CDC6 interacts in a high molecular complex in which a diverged Orc4 homologue and one replicative helicase subunit can also be found. Analysing the subcellular localization of four TbORC1/CDC6-interacting factors during the cell cycle reveals that one factor, TbORC1B, is not a static constituent of ORC but displays S-phase restricted nuclear localization and expression, suggesting it positively regulates replication. This work shows that ORC architecture and regulation are diverged features of DNA replication initiation in T. brucei, providing new insight into this key stage of eukaryotic genome copying. PMID:26951375

Role of AAA(+)-proteins in peroxisome biogenesis and function.

PubMed

Grimm, Immanuel; Erdmann, Ralf; Girzalsky, Wolfgang

2016-05-01

Mutations in the PEX1 gene, which encodes a protein required for peroxisome biogenesis, are the most common cause of the Zellweger spectrum diseases. The recognition that Pex1p shares a conserved ATP-binding domain with p97 and NSF led to the discovery of the extended family of AAA+-type ATPases. So far, four AAA+-type ATPases are related to peroxisome function. Pex6p functions together with Pex1p in peroxisome biogenesis, ATAD1/Msp1p plays a role in membrane protein targeting and a member of the Lon-family of proteases is associated with peroxisomal quality control. This review summarizes the current knowledge on the AAA+-proteins involved in peroxisome biogenesis and function.

ATPase-deficient mitochondrial inner membrane protein ATAD3A disturbs mitochondrial dynamics in dominant hereditary spastic paraplegia

PubMed Central

Cooper, Helen M.; Yang, Yang; Ylikallio, Emil; Khairullin, Rafil; Woldegebriel, Rosa; Lin, Kai-Lan; Euro, Liliya; Palin, Eino; Wolf, Alexander; Trokovic, Ras; Isohanni, Pirjo; Kaakkola, Seppo; Auranen, Mari; Lönnqvist, Tuula; Wanrooij, Sjoerd

2017-01-01

Abstract De novo mutations in ATAD3A (ATPase family AAA-domain containing protein 3A) were recently found to cause a neurological syndrome with developmental delay, hypotonia, spasticity, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. Using whole-exome sequencing, we identified a dominantly inherited heterozygous variant c.1064G > A (p.G355D) in ATAD3A in a mother presenting with hereditary spastic paraplegia (HSP) and axonal neuropathy and her son with dyskinetic cerebral palsy, both with disease onset in childhood. HSP is a clinically and genetically heterogeneous disorder of the upper motor neurons. Symptoms beginning in early childhood may resemble spastic cerebral palsy. The function of ATAD3A, a mitochondrial inner membrane AAA ATPase, is yet undefined. AAA ATPases form hexameric rings, which are catalytically dependent on the co-operation of the subunits. The dominant-negative patient mutation affects the Walker A motif, which is responsible for ATP binding in the AAA module of ATAD3A, and we show that the recombinant mutant ATAD3A protein has a markedly reduced ATPase activity. We further show that overexpression of the mutant ATAD3A fragments the mitochondrial network and induces lysosome mass. Similarly, we observed altered dynamics of the mitochondrial network and increased lysosomes in patient fibroblasts and neurons derived through differentiation of patient-specific induced pluripotent stem cells. These alterations were verified in patient fibroblasts to associate with upregulated basal autophagy through mTOR inactivation, resembling starvation. Mutations in ATAD3A can thus be dominantly inherited and underlie variable neurological phenotypes, including HSP, with intrafamiliar variability. This finding extends the group of mitochondrial inner membrane AAA proteins associated with spasticity. PMID:28158749

The Multivesicular Bodies (MVBs)-Localized AAA ATPase LRD6-6 Inhibits Immunity and Cell Death Likely through Regulating MVBs-Mediated Vesicular Trafficking in Rice

PubMed Central

Liang, Sihui; Liang, Ruihong; Zhou, Xiaogang; Chen, Zhixiong; Zhao, Wen; Wang, Jing; Li, Weitao; He, Min; Yuan, Can; Miyamoto, Koji; Ma, Bingtian; Wang, Jichun; Qin, Peng; Chen, Weilan; Wang, Yuping; Wang, Wenming; Wu, Xianjun; Yamane, Hisakazu; Zhu, Lihuang; Li, Shigui; Chen, Xuewei

2016-01-01

Previous studies have shown that multivesicular bodies (MVBs)/endosomes-mediated vesicular trafficking may play key roles in plant immunity and cell death. However, the molecular regulation is poorly understood in rice. Here we report the identification and characterization of a MVBs-localized AAA ATPase LRD6-6 in rice. Disruption of LRD6-6 leads to enhanced immunity and cell death in rice. The ATPase activity and homo-dimerization of LRD6-6 is essential for its regulation on plant immunity and cell death. An ATPase inactive mutation (LRD6-6E315Q) leads to dominant-negative inhibition in plants. The LRD6-6 protein co-localizes with the MVBs marker protein RabF1/ARA6 and interacts with ESCRT-III components OsSNF7 and OsVPS2. Further analysis reveals that LRD6-6 is required for MVBs-mediated vesicular trafficking and inhibits the biosynthesis of antimicrobial compounds. Collectively, our study shows that the AAA ATPase LRD6-6 inhibits plant immunity and cell death most likely through modulating MVBs-mediated vesicular trafficking in rice. PMID:27618555

Structure and Function of p97 and Pex1/6 Type II AAA+ Complexes.

PubMed

Saffert, Paul; Enenkel, Cordula; Wendler, Petra

2017-01-01

Protein complexes of the Type II AAA+ (ATPases associated with diverse cellular activities) family are typically hexamers of 80-150 kDa protomers that harbor two AAA+ ATPase domains. They form double ring assemblies flanked by associated domains, which can be N-terminal, intercalated or C-terminal to the ATPase domains. Most prominent members of this family include NSF (N-ethyl-maleimide sensitive factor), p97/VCP (valosin-containing protein), the Pex1/Pex6 complex and Hsp104 in eukaryotes and ClpB in bacteria. Tremendous efforts have been undertaken to understand the conformational dynamics of protein remodeling type II AAA+ complexes. A uniform mode of action has not been derived from these works. This review focuses on p97/VCP and the Pex1/6 complex, which both structurally remodel ubiquitinated substrate proteins. P97/VCP plays a role in many processes, including ER- associated protein degradation, and the Pex1/Pex6 complex dislocates and recycles the transport receptor Pex5 from the peroxisomal membrane during peroxisomal protein import. We give an introduction into existing knowledge about the biochemical and cellular activities of the complexes before discussing structural information. We particularly emphasize recent electron microscopy structures of the two AAA+ complexes and summarize their structural differences.

The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders

PubMed Central

Law, Kelsey B.; Bronte-Tinkew, Dana; Di Pietro, Erminia; Snowden, Ann; Jones, Richard O.; Moser, Ann; Brumell, John H.; Braverman, Nancy

2017-01-01

ABSTRACT Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs. PMID:28521612

The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders.

PubMed

Law, Kelsey B; Bronte-Tinkew, Dana; Di Pietro, Erminia; Snowden, Ann; Jones, Richard O; Moser, Ann; Brumell, John H; Braverman, Nancy; Kim, Peter K

2017-05-04

Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs.

The General Definition of the p97/Valosin-containing Protein (VCP)-interacting Motif (VIM) Delineates a New Family of p97 Cofactors*

PubMed Central

Stapf, Christopher; Cartwright, Edward; Bycroft, Mark; Hofmann, Kay; Buchberger, Alexander

2011-01-01

Cellular functions of the essential, ubiquitin-selective AAA ATPase p97/valosin-containing protein (VCP) are controlled by regulatory cofactors determining substrate specificity and fate. Most cofactors bind p97 through a ubiquitin regulatory X (UBX) or UBX-like domain or linear sequence motifs, including the hitherto ill defined p97/VCP-interacting motif (VIM). Here, we present the new, minimal consensus sequence RX5AAX2R as a general definition of the VIM that unites a novel family of known and putative p97 cofactors, among them UBXD1 and ZNF744/ANKZF1. We demonstrate that this minimal VIM consensus sequence is necessary and sufficient for p97 binding. Using NMR chemical shift mapping, we identified several residues of the p97 N-terminal domain (N domain) that are critical for VIM binding. Importantly, we show that cellular stress resistance conferred by the yeast VIM-containing cofactor Vms1 depends on the physical interaction between its VIM and the critical N domain residues of the yeast p97 homolog, Cdc48. Thus, the VIM-N domain interaction characterized in this study is required for the physiological function of Vms1 and most likely other members of the newly defined VIM family of cofactors. PMID:21896481

Comparative Proteomics Reveals Timely Transport into Cilia of Regulators or Effectors as a Mechanism Underlying Ciliary Disassembly.

PubMed

Wang, Limei; Gu, Lixiao; Meng, Dan; Wu, Qiong; Deng, Haiteng; Pan, Junmin

2017-07-07

Primary cilia are assembled and disassembled during cell cycle progression. During ciliary disassembly, ciliary axonemal microtubules (MTs) are depolymerized accompanied by extensive posttranslational protein modifications of ciliary proteins including protein phosphorylation, methylation, and ubiquitination. These events are hypothesized to involve transport of effectors or regulators into cilia at the time of ciliary disassembly from the cell body. To prove this hypothesis and identify new proteins involved in ciliary disassembly, we analyzed disassembling flagella in Chlamydomonas using comparative proteomics with TMT labeling. Ninety-one proteins were found to increase more than 1.4-fold in four replicates. The proteins of the IFT machinery not only increase but also exhibit stoichiometric changes. The other proteins that increase include signaling molecules, chaperones, and proteins involved in microtubule dynamics or stability. In particular, we have identified a ciliopathy protein C21orf2, the AAA-ATPase CDC48, that is involved in segregating polypeptides from large assemblies or cellular structures, FAP203 and FAP236, which are homologous to stabilizers of axonemal microtubules. Our data demonstrate that ciliary transport of effectors or regulators is one of the mechanisms underlying ciliary disassembly. Further characterization of the proteins identified will provide new insights into our understanding of ciliary disassembly and likely ciliopathy.

Roles of conserved arginines in ATP-binding domains of AAA+ chaperone ClpB from Thermus thermophilus.

PubMed

Yamasaki, Takashi; Nakazaki, Yosuke; Yoshida, Masasuke; Watanabe, Yo-hei

2011-07-01

ClpB, a member of the expanded superfamily of ATPases associated with diverse cellular activities (AAA+), forms a ring-shaped hexamer and cooperates with the DnaK chaperone system to reactivate aggregated proteins in an ATP-dependent manner. The ClpB protomer consists of an N-terminal domain, an AAA+ module (AAA-1), a middle domain, and a second AAA+ module (AAA-2). Each AAA+ module contains highly conserved WalkerA and WalkerB motifs, and two arginines (AAA-1) or one arginine (AAA-2). Here, we investigated the roles of these arginines (Arg322, Arg323, and Arg747) of ClpB from Thermus thermophilus in the ATPase cycle and chaperone function by alanine substitution. These mutations did not affect nucleotide binding, but did inhibit the hydrolysis of the bound ATP and slow the threading of the denatured protein through the central pore of the T. thermophilus ClpB ring, which severely impaired the chaperone functions. Previously, it was demonstrated that ATP binding to the AAA-1 module induced motion of the middle domain and stabilized the ClpB hexamer. However, the arginine mutations of the AAA-1 module destabilized the ClpB hexamer, even though ATP-induced motion of the middle domain was not affected. These results indicated that the three arginines are crucial for ATP hydrolysis and chaperone activity, but not for ATP binding. In addition, the two arginines in AAA-1 and the ATP-induced motion of the middle domain independently contribute to the stabilization of the hexamer. © 2011 The Authors Journal compilation © 2011 FEBS.

Role of mitochondrial processing peptidase and AAA proteases in processing of the yeast acetohydroxyacid synthase precursor.

PubMed

Dasari, Suvarna; Kölling, Ralf

2016-07-01

We studied presequence processing of the mitochondrial-matrix targeted acetohydroxyacid synthase (Ilv2). C-terminal 3HA-tagging altered the cleavage pattern from a single step to sequential two-step cleavage, giving rise to two Ilv2-3HA forms (A and B). Both cleavage events were dependent on the mitochondrial processing peptidase (MPP). We present evidence for the involvement of three AAA ATPases, m- and i-AAA proteases, and Mcx1, in Ilv2-3HA processing. Both, precursor to A-form and A-form to B-form cleavage were strongly affected in a ∆yme1 mutant. These defects could be suppressed by overexpression of MPP, suggesting that MPP activity is limiting in the ∆yme1 mutant. Our data suggest that for some substrates AAA ATPases could play an active role in the translocation of matrix-targeted proteins.

Structural Basis of ATP Hydrolysis and Intersubunit Signaling in the AAA+ ATPase p97.

PubMed

Hänzelmann, Petra; Schindelin, Hermann

2016-01-05

p97 belongs to the superfamily of AAA+ ATPases and is characterized by a tandem AAA module, an N-terminal domain involved in substrate and cofactor interactions, and a functionally important unstructured C-terminal tail. The ATPase activity is controlled by an intradomain communication within the same protomer and an interdomain communication between neighboring protomers. Here, we present for the first time crystal structures in which the physiologically relevant p97 hexamer constitutes the content of the asymmetric unit, namely in the apo state without nucleotide in either the D1 or D2 module and in the pre-activated state with ATPγS bound to both modules. The structures provide new mechanistic insights into the interdomain communication mediated by conformational changes of the C terminus as well as an intersubunit signaling network, which couples the nucleotide state to the conformation of the central putative substrate binding pore. Copyright © 2016 Elsevier Ltd. All rights reserved.

Species-specific serine-threonine protein kinase Pkb2 of Bifidobacterium longum subsp. longum: Genetic environment and substrate specificity.

PubMed

Nezametdinova, V Z; Mavletova, D A; Alekseeva, M G; Chekalina, M S; Zakharevich, N V; Danilenko, V N

2018-06-01

The objective of this study was to determine for phosphorylated substrates of the species-specific serine-threonine protein kinase (STPK) Pkb2 from Bifidobacterium longum subsp. longum GT15. Two approaches were employed: analyses of phosphorylated membrane vesicles protein spectra following kinase reactions and analyses of the genes surrounding pkb2. A bioinformatics analysis of the genes surrounding pkb2 found a species-specific gene cluster PFNA in the genomes of 34 different bifidobacterial species. The identified cluster consisted of 5-8 genes depending on the species. The first five genes are characteristic for all considered species. These are the following genes encoding serine-threonine protein kinase (pkb2), fibronectin type III domain-containing protein (fn3), AAA-ATPase (aaa-atp), hypothetical protein with DUF58 domain (duf58) and transglutaminase (tgm). The sixth (protein phosphatase, prpC), seventh (hypothetical protein, BLGT_RS02790), and eighth (FHA domain-containing protein, fha) genes are included in this cluster, but they are not found in all species. The operon organization of the PFNA gene cluster was confirmed with transcriptional analysis. AAA-ATPase, which is encoded by a gene of the PFNA gene cluster, was found to be a substrate of the STPK Pkb2. Fourteen AAA-ATPase sites (seven serine, six threonine, and one tyrosine) phosphorylated by STPK Pkb2 were revealed. Analysis of the spectra of phosphorylated membrane vesicles proteins allowed us to identify eleven proteins that were considered as possible Pkb2 substrates. They belong to several functional classes: proteins involved in transcription and translation; proteins of the F1-domain of the FoF1-ATPase; ABC-transporters; molecular chaperone GroEL; and glutamine synthase, GlnA1. All identified proteins were considered moonlighting proteins. Three out of 11 proteins (glutamine synthetase GlnA1 and FoF1-ATPase alpha and beta subunits) were selected for further in vitro phosphorylation assays and were shown to be phosphorylated by Pkb2. Four phosphorylated substrates of the species-specific STPK Pkb2 from B. longum subsp. longum GT15 were identified for the first time. They included the moonlighting protein glutamine synthase GlnA, FoF1-ATPase alpha and beta subunits, and the chaperone MoxR family of AAA-ATPase. The ability of bifidobacterial STPK to phosphorylate the substrate on serine, threonine, and tyrosine residues was shown for the first time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Asymmetric processing of a substrate protein in sequential allosteric cycles of AAA+ nanomachines

NASA Astrophysics Data System (ADS)

Kravats, Andrea N.; Tonddast-Navaei, Sam; Bucher, Ryan J.; Stan, George

2013-09-01

Essential protein quality control includes mechanisms of substrate protein (SP) unfolding and translocation performed by powerful ring-shaped AAA+ (ATPases associated with various cellular activities) nanomachines. These SP remodeling actions are effected by mechanical forces imparted by AAA+ loops that protrude into the central channel. Sequential intra-ring allosteric motions, which underlie repetitive SP-loop interactions, have been proposed to comprise clockwise (CW), counterclockwise (CCW), or random (R) conformational transitions of individual AAA+ subunits. To probe the effect of these allosteric mechanisms on unfoldase and translocase functions, we perform Langevin dynamics simulations of a coarse-grained model of an all-alpha SP processed by the single-ring ClpY ATPase or by the double-ring p97 ATPase. We find that, in all three allosteric mechanisms, the SP undergoes conformational transitions along a common set of pathways, which reveals that the active work provided by the ClpY machine involves single loop-SP interactions. Nevertheless, the rates and yields of SP unfolding and translocation are controlled by mechanism-dependent loop-SP binding events, as illustrated by faster timescales of SP processing in CW allostery compared with CCW and R allostery. The distinct efficacy of allosteric mechanisms is due to the asymmetric collaboration of adjacent subunits, which involves CW-biased structural motions of AAA+ loops and results in CW-compatible torque applied onto the SP. Additional simulations of mutant ClpY rings, which render a subset of subunits catalytically-defective or reduce their SP binding affinity, reveal that subunit-based conformational transitions play the major role in SP remodeling. Based on these results we predict that the minimally functional AAA+ ring includes three active subunits, only two of which are adjacent.

DNA binding polarity, dimerization, and ATPase ring remodeling in the CMG helicase of the eukaryotic replisome

PubMed Central

Costa, Alessandro; Renault, Ludovic; Swuec, Paolo; Petojevic, Tatjana; Pesavento, James J; Ilves, Ivar; MacLellan-Gibson, Kirsty; Fleck, Roland A; Botchan, Michael R; Berger, James M

2014-01-01

The Cdc45/Mcm2-7/GINS (CMG) helicase separates DNA strands during replication in eukaryotes. How the CMG is assembled and engages DNA substrates remains unclear. Using electron microscopy, we have determined the structure of the CMG in the presence of ATPγS and a DNA duplex bearing a 3′ single-stranded tail. The structure shows that the MCM subunits of the CMG bind preferentially to single-stranded DNA, establishes the polarity by which DNA enters into the Mcm2-7 pore, and explains how Cdc45 helps prevent DNA from dissociating from the helicase. The Mcm2-7 subcomplex forms a cracked-ring, right-handed spiral when DNA and nucleotide are bound, revealing unexpected congruencies between the CMG and both bacterial DnaB helicases and the AAA+ motor of the eukaryotic proteasome. The existence of a subpopulation of dimeric CMGs establishes the subunit register of Mcm2-7 double hexamers and together with the spiral form highlights how Mcm2-7 transitions through different conformational and assembly states as it matures into a functional helicase. DOI: http://dx.doi.org/10.7554/eLife.03273.001 PMID:25117490

Structural basis of protein translocation by the Vps4-Vta1 AAA ATPase

PubMed Central

Monroe, Nicole; Han, Han; Shen, Peter S; Sundquist, Wesley I; Hill, Christopher P

2017-01-01

Many important cellular membrane fission reactions are driven by ESCRT pathways, which culminate in disassembly of ESCRT-III polymers by the AAA ATPase Vps4. We report a 4.3 Å resolution cryo-EM structure of the active Vps4 hexamer with its cofactor Vta1, ADP·BeFx, and an ESCRT-III substrate peptide. Four Vps4 subunits form a helix whose interfaces are consistent with ATP binding, is stabilized by Vta1, and binds the substrate peptide. The fifth subunit approximately continues this helix but appears to be dissociating. The final Vps4 subunit completes a notched-washer configuration as if transitioning between the ends of the helix. We propose that ATP binding propagates growth at one end of the helix while hydrolysis promotes disassembly at the other end, so that Vps4 ‘walks’ along ESCRT-III until it encounters the ordered N-terminal domain to destabilize the ESCRT-III lattice. This model may be generally applicable to other protein-translocating AAA ATPases. DOI: http://dx.doi.org/10.7554/eLife.24487.001 PMID:28379137

Mechanism of the AAA+ ATPases pontin and reptin in the biogenesis of H/ACA RNPs.

PubMed

Machado-Pinilla, Rosario; Liger, Dominique; Leulliot, Nicolas; Meier, U Thomas

2012-10-01

The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes.

Mechanism of the AAA+ ATPases pontin and reptin in the biogenesis of H/ACA RNPs

PubMed Central

Machado-Pinilla, Rosario; Liger, Dominique; Leulliot, Nicolas; Meier, U. Thomas

2012-01-01

The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes. PMID:22923768

TRIP13 is a protein-remodeling AAA+ ATPase that catalyzes MAD2 conformation switching

DOE PAGES

Ye, Qiaozhen; Rosenberg, Scott C.; Moeller, Arne; ...

2015-04-28

The AAA+ family ATPase TRIP13 is a key regulator of meiotic recombination and the spindle assembly checkpoint, acting on signaling proteins of the conserved HORMA domain family. Here we present the structure of the Caenorhabditis elegans TRIP13 ortholog PCH-2, revealing a new family of AAA+ ATPase protein remodelers. PCH-2 possesses a substrate-recognition domain related to those of the protein remodelers NSF and p97, while its overall hexameric architecture and likely structural mechanism bear close similarities to the bacterial protein unfoldase ClpX. We find that TRIP13, aided by the adapter protein p31(comet), converts the HORMA-family spindle checkpoint protein MAD2 from amore » signaling-active ‘closed’ conformer to an inactive ‘open’ conformer. We propose that TRIP13 and p31(comet) collaborate to inactivate the spindle assembly checkpoint through MAD2 conformational conversion and disassembly of mitotic checkpoint complexes. A parallel HORMA protein disassembly activity likely underlies TRIP13's critical regulatory functions in meiotic chromosome structure and recombination.« less

Heat Shock Response of Archaeoglobus fulgidus†

PubMed Central

Rohlin, Lars; Trent, Jonathan D.; Salmon, Kirsty; Kim, Unmi; Gunsalus, Robert P.; Liao, James C.

2005-01-01

The heat shock response of the hyperthermophilic archaeon Archaeoglobus fulgidus strain VC-16 was studied using whole-genome microarrays. On the basis of the resulting expression profiles, approximately 350 of the 2,410 open reading frames (ORFs) (ca. 14%) exhibited increased or decreased transcript abundance. These span a range of cell functions, including energy production, amino acid metabolism, and signal transduction, where the majority are uncharacterized. One ORF called AF1298 was identified that contains a putative helix-turn-helix DNA binding motif. The gene product, HSR1, was expressed and purified from Escherichia coli and was used to characterize specific DNA recognition regions upstream of two A. fulgidus genes, AF1298 and AF1971. The results indicate that AF1298 is autoregulated and is part of an operon with two downstream genes that encode a small heat shock protein, Hsp20, and cdc48, an AAA+ ATPase. The DNase I footprints using HSR1 suggest the presence of a cis-binding motif upstream of AF1298 consisting of CTAAC-N5-GTTAG. Since AF1298 is negatively regulated in response to heat shock and encodes a protein only distantly related to the N-terminal DNA binding domain of Phr of Pyrococcus furiosus, these results suggest that HSR1 and Phr may belong to an evolutionarily diverse protein family involved in heat shock regulation in hyperthermophilic and mesophilic Archaea organisms. PMID:16109946

Engagement of Arginine Finger to ATP Triggers Large Conformational Changes in NtrC1 AAA+ ATPase for Remodeling Bacterial RNA Polymerase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Baoyu; Sysoeva, Tatyana A.; Chowdhury, Saikat

The NtrC-like AAA+ ATPases control virulence and other important bacterial activities through delivering mechanical work to {sigma}54-RNA polymerase to activate transcription from {sigma}54-dependent genes. We report the first crystal structure for such an ATPase, NtrC1 of Aquifex aeolicus, in which the catalytic arginine engages the {gamma}-phosphate of ATP. Comparing the new structure with those previously known for apo and ADP-bound states supports a rigid-body displacement model that is consistent with large-scale conformational changes observed by low-resolution methods. First, the arginine finger induces rigid-body roll, extending surface loops above the plane of the ATPase ring to bind {sigma}54. Second, ATP hydrolysismore » permits Pi release and retraction of the arginine with a reversed roll, remodeling {sigma}54-RNAP. This model provides a fresh perspective on how ATPase subunits interact within the ring-ensemble to promote transcription, directing attention to structural changes on the arginine-finger side of an ATP-bound interface.« less

A structural basis for the regulatory inactivation of DnaA.

PubMed

Xu, Qingping; McMullan, Daniel; Abdubek, Polat; Astakhova, Tamara; Carlton, Dennis; Chen, Connie; Chiu, Hsiu-Ju; Clayton, Thomas; Das, Debanu; Deller, Marc C; Duan, Lian; Elsliger, Marc-Andre; Feuerhelm, Julie; Hale, Joanna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K; Johnson, Hope A; Klock, Heath E; Knuth, Mark W; Kozbial, Piotr; Sri Krishna, S; Kumar, Abhinav; Marciano, David; Miller, Mitchell D; Morse, Andrew T; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Oommachen, Silvya; Paulsen, Jessica; Puckett, Christina; Reyes, Ron; Rife, Christopher L; Sefcovic, Natasha; Trame, Christine; van den Bedem, Henry; Weekes, Dana; Hodgson, Keith O; Wooley, John; Deacon, Ashley M; Godzik, Adam; Lesley, Scott A; Wilson, Ian A

2009-01-16

Regulatory inactivation of DnaA is dependent on Hda (homologous to DnaA), a protein homologous to the AAA+ (ATPases associated with diverse cellular activities) ATPase region of the replication initiator DnaA. When bound to the sliding clamp loaded onto duplex DNA, Hda can stimulate the transformation of active DnaA-ATP into inactive DnaA-ADP. The crystal structure of Hda from Shewanella amazonensis SB2B at 1.75 A resolution reveals that Hda resembles typical AAA+ ATPases. The arrangement of the two subdomains in Hda (residues 1-174 and 175-241) differs dramatically from that of DnaA. A CDP molecule anchors the Hda domains in a conformation that promotes dimer formation. The Hda dimer adopts a novel oligomeric assembly for AAA+ proteins in which the arginine finger, crucial for ATP hydrolysis, is fully exposed and available to hydrolyze DnaA-ATP through a typical AAA+ type of mechanism. The sliding clamp binding motifs at the N-terminus of each Hda monomer are partially buried and combine to form an antiparallel beta-sheet at the dimer interface. The inaccessibility of the clamp binding motifs in the CDP-bound structure of Hda suggests that conformational changes are required for Hda to form a functional complex with the clamp. Thus, the CDP-bound Hda dimer likely represents an inactive form of Hda.

Two subunits of human ORC are dispensable for DNA replication and proliferation.

PubMed

Shibata, Etsuko; Kiran, Manjari; Shibata, Yoshiyuki; Singh, Samarendra; Kiran, Shashi; Dutta, Anindya

2016-12-01

The six-subunit Origin Recognition Complex (ORC) is believed to be an essential eukaryotic ATPase that binds to origins of replication as a ring-shaped heterohexamer to load MCM2-7 and initiate DNA replication. We have discovered that human cell lines in culture proliferate with intact chromosomal origins of replication after disruption of both alleles of ORC2 or of the ATPase subunit, ORC1 . The ORC1 or ORC2 -depleted cells replicate with decreased chromatin loading of MCM2-7 and become critically dependent on another ATPase, CDC6, for survival and DNA replication. Thus, either the ORC ring lacking a subunit, even its ATPase subunit, can load enough MCM2-7 in partnership with CDC6 to initiate DNA replication, or cells have an ORC-independent, CDC6-dependent mechanism to load MCM2-7 on origins of replication.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hood, Iris V.; Berger, James M.

Replisome assembly requires the loading of replicative hexameric helicases onto origins by AAA+ ATPases. How loader activity is appropriately controlled remains unclear. Here, we use structural and biochemical analyses to establish how an antimicrobial phage protein interferes with the function of theStaphylococcus aureusreplicative helicase loader, DnaI. The viral protein binds to the loader’s AAA+ ATPase domain, allowing binding of the host replicative helicase but impeding loader self-assembly and ATPase activity. Close inspection of the complex highlights an unexpected locus for the binding of an interdomain linker element in DnaI/DnaC-family proteins. We find that the inhibitor protein is genetically coupled tomore » a phage-encoded homolog of the bacterial helicase loader, which we show binds to the host helicase but not to the inhibitor itself. These findings establish a new approach by which viruses can hijack host replication processes and explain how loader activity is internally regulated to prevent aberrant auto-association.« less

The major-effect quantitative trait locus CsARN6.1 encodes an AAA ATPase domain-containing protein that is associated with waterlogging stress tolerance by promoting adventitious root formation.

PubMed

Xu, Xuewen; Ji, Jing; Xu, Qiang; Qi, Xiaohua; Weng, Yiqun; Chen, Xuehao

2018-03-01

In plants, the formation of hypocotyl-derived adventitious roots (ARs) is an important morphological acclimation to waterlogging stress; however, its genetic basis remains fragmentary. Here, through combined use of bulked segregant analysis-based whole-genome sequencing, SNP haplotyping and fine genetic mapping, we identified a candidate gene for a major-effect QTL, ARN6.1, that was responsible for waterlogging tolerance due to increased AR formation in the cucumber line Zaoer-N. Through multiple lines of evidence, we show that CsARN6.1 is the most possible candidate for ARN6.1 which encodes an AAA ATPase. The increased formation of ARs under waterlogging in Zaoer-N could be attributed to a non-synonymous SNP in the coiled-coil domain region of this gene. CsARN6.1 increases the number of ARs via its ATPase activity. Ectopic expression of CsARN6.1 in Arabidopsis resulted in better rooting ability and lateral root development in transgenic plants. Transgenic cucumber expressing the CsARN6.1 Asp allele from Zaoer-N exhibited a significant increase in number of ARs compared with the wild type expressing the allele from Pepino under waterlogging conditions. Taken together, these data support that the AAA ATPase gene CsARN6.1 has an important role in increasing cucumber AR formation and waterlogging tolerance. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Mechanistic insights into c-di-GMP–dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa

DOE PAGES

Matsuyama, Bruno Y.; Krasteva, Petya V.; Baraquet, Claudine; ...

2015-12-28

Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ 54-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response tomore » cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ’s AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP–complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs.« less

Mechanistic insights into c-di-GMP–dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuyama, Bruno Y.; Krasteva, Petya V.; Baraquet, Claudine

Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ 54-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response tomore » cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ’s AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP–complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs.« less

Mechanistic insights into c-di-GMP–dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa

PubMed Central

Matsuyama, Bruno Y.; Krasteva, Petya V.; Baraquet, Claudine; Harwood, Caroline S.; Sondermann, Holger; Navarro, Marcos V. A. S.

2016-01-01

Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ54-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response to cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ’s AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP–complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs. PMID:26712005

Conformational Landscape of the p28-Bound Human Proteasome Regulatory Particle.

PubMed

Lu, Ying; Wu, Jiayi; Dong, Yuanchen; Chen, Shuobing; Sun, Shuangwu; Ma, Yong-Bei; Ouyang, Qi; Finley, Daniel; Kirschner, Marc W; Mao, Youdong

2017-07-20

The proteasome holoenzyme is activated by its regulatory particle (RP) consisting of two subcomplexes, the lid and the base. A key event in base assembly is the formation of a heterohexameric ring of AAA-ATPases, which is guided by at least four RP assembly chaperones in mammals: PAAF1, p28/gankyrin, p27/PSMD9, and S5b. Using cryogenic electron microscopy, we analyzed the non-AAA structure of the p28-bound human RP at 4.5 Å resolution and determined seven distinct conformations of the Rpn1-p28-AAA subcomplex within the p28-bound RP at subnanometer resolutions. Remarkably, the p28-bound AAA ring does not form a channel in the free RP and spontaneously samples multiple "open" and "closed" topologies at the Rpt2-Rpt6 and Rpt3-Rpt4 interfaces. Our analysis suggests that p28 assists the proteolytic core particle to select a specific conformation of the ATPase ring for RP engagement and is released in a shoehorn-like fashion in the last step of the chaperone-mediated proteasome assembly. Copyright © 2017 Elsevier Inc. All rights reserved.

New Regulators of Clathrin-Mediated Endocytosis Identified in Saccharomyces cerevisiae by Systematic Quantitative Fluorescence Microscopy

PubMed Central

Farrell, Kristen B.; Grossman, Caitlin; Di Pietro, Santiago M.

2015-01-01

Despite the importance of clathrin-mediated endocytosis (CME) for cell biology, it is unclear if all components of the machinery have been discovered and many regulatory aspects remain poorly understood. Here, using Saccharomyces cerevisiae and a fluorescence microscopy screening approach we identify previously unknown regulatory factors of the endocytic machinery. We further studied the top scoring protein identified in the screen, Ubx3, a member of the conserved ubiquitin regulatory X (UBX) protein family. In vivo and in vitro approaches demonstrate that Ubx3 is a new coat component. Ubx3-GFP has typical endocytic coat protein dynamics with a patch lifetime of 45 ± 3 sec. Ubx3 contains a W-box that mediates physical interaction with clathrin and Ubx3-GFP patch lifetime depends on clathrin. Deletion of the UBX3 gene caused defects in the uptake of Lucifer Yellow and the methionine transporter Mup1 demonstrating that Ubx3 is needed for efficient endocytosis. Further, the UBX domain is required both for localization and function of Ubx3 at endocytic sites. Mechanistically, Ubx3 regulates dynamics and patch lifetime of the early arriving protein Ede1 but not later arriving coat proteins or actin assembly. Conversely, Ede1 regulates the patch lifetime of Ubx3. Ubx3 likely regulates CME via the AAA-ATPase Cdc48, a ubiquitin-editing complex. Our results uncovered new components of the CME machinery that regulate this fundamental process. PMID:26362318

Structural insights into the p97-Ufd1-Npl4 complex

PubMed Central

Pye, Valerie E.; Beuron, Fabienne; Keetch, Catherine A.; McKeown, Ciaran; Robinson, Carol V.; Meyer, Hemmo H.; Zhang, Xiaodong; Freemont, Paul S.

2007-01-01

p97/VCP (Cdc48 in yeast) is an essential and abundant member of the AAA+ family of ATPases and is involved in a number of diverse cellular pathways through interactions with different adaptor proteins. The two most characterized adaptors for p97 are p47 and the Ufd1 (ubiquitin fusion degradation 1)-Npl4 (nuclear protein localization 4) complex. p47 directs p97 to membrane fusion events and has been shown to be involved in protein degradation. The Ufd1-Npl4 complex directs p97 to an essential role in endoplasmic reticulum-associated degradation and an important role in mitotic spindle disassembly postmitosis. Here we describe the structural features of the Ufd1-Npl4 complex and its interaction with p97 with the aid of EM and other biophysical techniques. The Ufd1-Npl4 heterodimer has an elongated bilobed structure that is ≈80 × 30 Å in dimension. One Ufd1-Npl4 heterodimer is shown to interact with one p97 hexamer to form the p97-Ufd1-Npl4 complex. The Ufd1-Npl4 heterodimer emanates from one region on the periphery of the N-D1 plane of the p97 hexamer. Intriguingly, the p97-p47 and the p97-Ufd1-Npl4 complexes are significantly different in stoichiometry, symmetry, and quaternary arrangement, reflecting their specific actions and their ability to interact with additional cofactors that cooperate with p97 in diverse cellular pathways. PMID:17202270

The AAA+ proteins Pontin and Reptin enter adult age: from understanding their basic biology to the identification of selective inhibitors

PubMed Central

Matias, Pedro M.; Baek, Sung Hee; Bandeiras, Tiago M.; Dutta, Anindya; Houry, Walid A.; Llorca, Oscar; Rosenbaum, Jean

2015-01-01

Pontin and Reptin are related partner proteins belonging to the AAA+ (ATPases Associated with various cellular Activities) family. They are implicated in multiple and seemingly unrelated processes encompassing the regulation of gene transcription, the remodeling of chromatin, DNA damage sensing and repair, and the assembly of protein and ribonucleoprotein complexes, among others. The 2nd International Workshop on Pontin and Reptin took place at the Instituto de Tecnologia Química e Biológica António Xavier in Oeiras, Portugal on October 10–12, 2014, and reported significant new advances on the mechanisms of action of these two AAA+ ATPases. The major points under discussion were related to the mechanisms through which these proteins regulate gene transcription, their roles as co-chaperones, and their involvement in pathophysiology, especially in cancer and ciliary biology and disease. Finally, they may become anticancer drug targets since small chemical inhibitors were shown to produce anti-tumor effects in animal models. PMID:25988184

The AAA+ proteins Pontin and Reptin enter adult age: from understanding their basic biology to the identification of selective inhibitors.

PubMed

Matias, Pedro M; Baek, Sung Hee; Bandeiras, Tiago M; Dutta, Anindya; Houry, Walid A; Llorca, Oscar; Rosenbaum, Jean

2015-01-01

Pontin and Reptin are related partner proteins belonging to the AAA+ (ATPases Associated with various cellular Activities) family. They are implicated in multiple and seemingly unrelated processes encompassing the regulation of gene transcription, the remodeling of chromatin, DNA damage sensing and repair, and the assembly of protein and ribonucleoprotein complexes, among others. The 2nd International Workshop on Pontin and Reptin took place at the Instituto de Tecnologia Química e Biológica António Xavier in Oeiras, Portugal on October 10-12, 2014, and reported significant new advances on the mechanisms of action of these two AAA+ ATPases. The major points under discussion were related to the mechanisms through which these proteins regulate gene transcription, their roles as co-chaperones, and their involvement in pathophysiology, especially in cancer and ciliary biology and disease. Finally, they may become anticancer drug targets since small chemical inhibitors were shown to produce anti-tumor effects in animal models.

Structure of a AAA+ unfoldase in the process of unfolding substrate

PubMed Central

Ripstein, Zev A; Huang, Rui; Augustyniak, Rafal; Kay, Lewis E; Rubinstein, John L

2017-01-01

AAA+ unfoldases are thought to unfold substrate through the central pore of their hexameric structures, but how this process occurs is not known. VAT, the Thermoplasma acidophilum homologue of eukaryotic CDC48/p97, works in conjunction with the proteasome to degrade misfolded or damaged proteins. We show that in the presence of ATP, VAT with its regulatory N-terminal domains removed unfolds other VAT complexes as substrate. We captured images of this transient process by electron cryomicroscopy (cryo-EM) to reveal the structure of the substrate-bound intermediate. Substrate binding breaks the six-fold symmetry of the complex, allowing five of the six VAT subunits to constrict into a tight helix that grips an ~80 Å stretch of unfolded protein. The structure suggests a processive hand-over-hand unfolding mechanism, where each VAT subunit releases the substrate in turn before re-engaging further along the target protein, thereby unfolding it. DOI: http://dx.doi.org/10.7554/eLife.25754.001 PMID:28390173

Structural basis for the ATP-independent proteolytic activity of LonB proteases and reclassification of their AAA+ modules.

PubMed

An, Young Jun; Na, Jung-Hyun; Kim, Myung-Il; Cha, Sun-Shin

2015-10-01

Lon proteases degrade defective or denature proteins as well as some folded proteins for the control of cellular protein quality. There are two types of Lon proteases, LonA and LonB. Each consists of two functional components: a protease component and an ATPase associated with various cellular activities (AAA+ module). Here, we report the 2.03 -resolution crystal structure of the isolated AAA+ module (iAAA+ module) of LonB from Thermococcus onnurineus NA1 (TonLonB). The iAAA+ module, having no bound nucleotide, adopts a conformation virtually identical to the ADP-bound conformation of AAA+ modules in the hexameric structure of TonLonB; this provides insights into the ATP-independent proteolytic activity observed in a LonB protease. Structural comparison of AAA+ modules between LonA and LonB revealed that the AAA+ modules of Lon proteases are separated into two distinct clades depending on their structural features. The AAA+ module of LonB belongs to the -H2 & Ins1 insert clade (HINS clade)- defined for the first time in this study, while the AAA+ module of LonA is a member of the HCLR clade.

A Structural Basis for the Regulatory Inactivation of DnaA

PubMed Central

Xu, Qingping; McMullan, Daniel; Abdubek, Polat; Astakhova, Tamara; Carlton, Dennis; Chen, Connie; Chiu, Hsiu-Ju; Clayton, Thomas; Das, Debanu; Deller, Marc C.; Duan, Lian; Elsliger, Marc-Andre; Feuerhelm, Julie; Hale, Joanna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Johnson, Hope A.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Krishna, S. Sri; Kumar, Abhinav; Marciano, David; Miller, Mitchell D.; Morse, Andrew T.; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Oommachen, Silvya; Paulsen, Jessica; Puckett, Christina; Reyes, Ron; Rife, Christopher L.; Sefcovic, Natasha; Trame, Christine; van den Bedem, Henry; Weekes, Dana; Hodgson, Keith O.; Wooley, John; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

2009-01-01

Summary Regulatory inactivation of DnaA is dependent on Hda, a protein homologous to the AAA+ ATPase region of the replication initiator DnaA. When bound to the sliding clamp loaded onto duplex DNA, Hda can stimulate the transformation of active DnaA-ATP into inactive DnaA-ADP. The crystal structure of Hda from Shewanella amazonensis SB2B at 1.75 Å resolution reveals that Hda resembles typical AAA+ ATPases. The arrangement of the two subdomains in Hda (residues 1-174, 175-241) differs dramatically from that of DnaA. A CDP molecule anchors the Hda domains in a conformation which promotes dimer formation. The Hda dimer adopts a novel oligomeric assembly for AAA+ proteins in which the arginine finger, crucial for ATP hydrolysis, is fully exposed and available to hydrolyze DnaA-ATP through a typical AAA+ type mechanism. The sliding clamp binding motifs at the N-terminus of each Hda monomer are partially buried and combine to form an antiparallel β-sheet at the dimer interface. The inaccessibility of the clamp binding motifs in the CDP bound structure of Hda suggests that conformational changes are required for Hda to form a functional complex with the clamp. Thus, the CDP-bound Hda dimer likely represents an inactive form of Hda. PMID:19000695

Poliovirus 2C protein forms homo-oligomeric structures required for ATPase activity.

PubMed

Adams, Peter; Kandiah, Eaazhisai; Effantin, Grégory; Steven, Alasdair C; Ehrenfeld, Ellie

2009-08-14

The poliovirus protein 2C plays an essential role in viral RNA replication, although its precise biochemical activities or structural requirements have not been elucidated. The protein has several distinctive properties, including ATPase activity and membrane and RNA binding, that are conserved among orthologs of many positive-strand RNA viruses. Sequence alignments have placed these proteins in the SF3 helicase family, a subset of the AAA+ ATPase superfamily. A feature common to AAA+ proteins is the formation of oligomeric rings that are essential for their catalytic functions. Here we show that a recombinant protein, MBP-2C, in which maltose-binding protein was fused to 2C, formed soluble oligomers and that ATPase activity was restricted to oligomer-containing fractions from gel-filtration chromatography. The active fraction was visualized by negative-staining electron microscopy as ring-like particles composed of 5-8 protomers. This conclusion was confirmed by mass measurements obtained by scanning transmission electron microscopy. Mutation of amino acid residues in the 2C nucleotide-binding domain demonstrated that loss of the ability to bind or hydrolyze ATP did not affect oligomerization. Co-expression of active MBP-2C and inactive mutant proteins generated mixed oligomers that exhibited little ATPase activity, suggesting that incorporation of inactive subunits eliminates the function of the entire particle. Finally, deletion of the N-terminal 38 amino acids blocked oligomerization of the fusion protein and eliminated ATPase activity, despite retention of an unaltered nucleotide-binding domain.

Poliovirus 2C Protein Forms Homo-oligomeric Structures Required for ATPase Activity*

PubMed Central

Adams, Peter; Kandiah, Eaazhisai; Effantin, Grégory; Steven, Alasdair C.; Ehrenfeld, Ellie

2009-01-01

The poliovirus protein 2C plays an essential role in viral RNA replication, although its precise biochemical activities or structural requirements have not been elucidated. The protein has several distinctive properties, including ATPase activity and membrane and RNA binding, that are conserved among orthologs of many positive-strand RNA viruses. Sequence alignments have placed these proteins in the SF3 helicase family, a subset of the AAA+ ATPase superfamily. A feature common to AAA+ proteins is the formation of oligomeric rings that are essential for their catalytic functions. Here we show that a recombinant protein, MBP-2C, in which maltose-binding protein was fused to 2C, formed soluble oligomers and that ATPase activity was restricted to oligomer-containing fractions from gel-filtration chromatography. The active fraction was visualized by negative-staining electron microscopy as ring-like particles composed of 5–8 protomers. This conclusion was confirmed by mass measurements obtained by scanning transmission electron microscopy. Mutation of amino acid residues in the 2C nucleotide-binding domain demonstrated that loss of the ability to bind or hydrolyze ATP did not affect oligomerization. Co-expression of active MBP-2C and inactive mutant proteins generated mixed oligomers that exhibited little ATPase activity, suggesting that incorporation of inactive subunits eliminates the function of the entire particle. Finally, deletion of the N-terminal 38 amino acids blocked oligomerization of the fusion protein and eliminated ATPase activity, despite retention of an unaltered nucleotide-binding domain. PMID:19520852

A structural analysis of the AAA+ domains in Saccharomyces cerevisiae cytoplasmic dynein

PubMed Central

Gleave, Emma S.; Schmidt, Helgo; Carter, Andrew P.

2014-01-01

Dyneins are large protein complexes that act as microtubule based molecular motors. The dynein heavy chain contains a motor domain which is a member of the AAA+ protein family (ATPases Associated with diverse cellular Activities). Proteins of the AAA+ family show a diverse range of functionalities, but share a related core AAA+ domain, which often assembles into hexameric rings. Dynein is unusual because it has all six AAA+ domains linked together, in one long polypeptide. The dynein motor domain generates movement by coupling ATP driven conformational changes in the AAA+ ring to the swing of a motile element called the linker. Dynein binds to its microtubule track via a long antiparallel coiled-coil stalk that emanates from the AAA+ ring. Recently the first high resolution structures of the dynein motor domain were published. Here we provide a detailed structural analysis of the six AAA+ domains using our Saccharomycescerevisiae crystal structure. We describe how structural similarities in the dynein AAA+ domains suggest they share a common evolutionary origin. We analyse how the different AAA+ domains have diverged from each other. We discuss how this is related to the function of dynein as a motor protein and how the AAA+ domains of dynein compare to those of other AAA+ proteins. PMID:24680784

An AAA Motor-Driven Mechanical Switch in Rpn11 Controls Deubiquitination at the 26S Proteasome.

PubMed

Worden, Evan J; Dong, Ken C; Martin, Andreas

2017-09-07

Poly-ubiquitin chains direct protein substrates to the 26S proteasome, where they are removed by the deubiquitinase Rpn11 during ATP-dependent substrate degradation. Rapid deubiquitination is required for efficient degradation but must be restricted to committed substrates that are engaged with the ATPase motor to prevent premature ubiquitin chain removal and substrate escape. Here we reveal the ubiquitin-bound structure of Rpn11 from S. cerevisiae and the mechanisms for mechanochemical coupling of substrate degradation and deubiquitination. Ubiquitin binding induces a conformational switch of Rpn11's Insert-1 loop from an inactive closed state to an active β hairpin. This switch is rate-limiting for deubiquitination and strongly accelerated by mechanical substrate translocation into the AAA+ motor. Deubiquitination by Rpn11 and ubiquitin unfolding by the ATPases are in direct competition. The AAA+ motor-driven acceleration of Rpn11 is therefore important to ensure that poly-ubiquitin chains are removed only from committed substrates and fast enough to prevent their co-degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

Loss of Drosophila i-AAA protease, dYME1L, causes abnormal mitochondria and apoptotic degeneration.

PubMed

Qi, Y; Liu, H; Daniels, M P; Zhang, G; Xu, H

2016-02-01

Mitochondrial AAA (ATPases Associated with diverse cellular Activities) proteases i-AAA (intermembrane space-AAA) and m-AAA (matrix-AAA) are closely related and have major roles in inner membrane protein homeostasis. Mutations of m-AAA proteases are associated with neuromuscular disorders in humans. However, the role of i-AAA in metazoans is poorly understood. We generated a deletion affecting Drosophila i-AAA, dYME1L (dYME1L(del)). Mutant flies exhibited premature aging, progressive locomotor deficiency and neurodegeneration that resemble some key features of m-AAA diseases. dYME1L(del) flies displayed elevated mitochondrial unfolded protein stress and irregular cristae. Aged dYME1L(del) flies had reduced complex I (NADH/ubiquinone oxidoreductase) activity, increased level of reactive oxygen species (ROS), severely disorganized mitochondrial membranes and increased apoptosis. Furthermore, inhibiting apoptosis by targeting dOmi (Drosophila Htra2/Omi) or DIAP1, or reducing ROS accumulation suppressed retinal degeneration. Our results suggest that i-AAA is essential for removing unfolded proteins and maintaining mitochondrial membrane architecture. Loss of i-AAA leads to the accumulation of oxidative damage and progressive deterioration of membrane integrity, which might contribute to apoptosis upon the release of proapoptotic molecules such as dOmi. Containing ROS level could be a potential strategy to manage mitochondrial AAA protease deficiency.

A structure- and chemical genomics-based approach for repositioning of drugs against VCP/p97 ATPase.

PubMed

Segura-Cabrera, Aldo; Tripathi, Reshmi; Zhang, Xiaoyi; Gui, Lin; Chou, Tsui-Fen; Komurov, Kakajan

2017-03-21

Valosin-containing protein (VCP/p97) ATPase (a.k.a. Cdc48) is a key member of the ER-associated protein degradation (ERAD) pathway. ERAD and VCP/p97 have been implicated in a multitude of human diseases, such as neurodegenerative diseases and cancer. Inhibition of VCP/p97 induces proteotoxic ER stress and cell death in cancer cells, making it an attractive target for cancer treatment. However, no drugs exist against this protein in the market. Repositioning of drugs towards new indications is an attractive alternative to the de novo drug development due to the potential for significantly shorter time to clinical translation. Here, we employed an integrative strategy for the repositioning of drugs as novel inhibitors of the VCP/p97 ATPase. We integrated structure-based virtual screening with the chemical genomics analysis of drug molecular signatures, and identified several candidate inhibitors of VCP/p97 ATPase. Importantly, experimental validation with cell-based and in vitro ATPase assays confirmed three (ebastine, astemizole and clotrimazole) out of seven tested candidates (~40% true hit rate) as direct inhibitors of VCP/p97 and ERAD. This study introduces an effective integrative strategy for drug repositioning, and identified new drugs against the VCP/p97/ERAD pathway in human diseases.

A structural analysis of the AAA+ domains in Saccharomyces cerevisiae cytoplasmic dynein.

PubMed

Gleave, Emma S; Schmidt, Helgo; Carter, Andrew P

2014-06-01

Dyneins are large protein complexes that act as microtubule based molecular motors. The dynein heavy chain contains a motor domain which is a member of the AAA+ protein family (ATPases Associated with diverse cellular Activities). Proteins of the AAA+ family show a diverse range of functionalities, but share a related core AAA+ domain, which often assembles into hexameric rings. Dynein is unusual because it has all six AAA+ domains linked together, in one long polypeptide. The dynein motor domain generates movement by coupling ATP driven conformational changes in the AAA+ ring to the swing of a motile element called the linker. Dynein binds to its microtubule track via a long antiparallel coiled-coil stalk that emanates from the AAA+ ring. Recently the first high resolution structures of the dynein motor domain were published. Here we provide a detailed structural analysis of the six AAA+ domains using our Saccharomycescerevisiae crystal structure. We describe how structural similarities in the dynein AAA+ domains suggest they share a common evolutionary origin. We analyse how the different AAA+ domains have diverged from each other. We discuss how this is related to the function of dynein as a motor protein and how the AAA+ domains of dynein compare to those of other AAA+ proteins. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

The pupylation machinery is involved in iron homeostasis by targeting the iron storage protein ferritin.

PubMed

Küberl, Andreas; Polen, Tino; Bott, Michael

2016-04-26

The balance of sufficient iron supply and avoidance of iron toxicity by iron homeostasis is a prerequisite for cellular metabolism and growth. Here we provide evidence that, in Actinobacteria, pupylation plays a crucial role in this process. Pupylation is a posttranslational modification in which the prokaryotic ubiquitin-like protein Pup is covalently attached to a lysine residue in target proteins, thus resembling ubiquitination in eukaryotes. Pupylated proteins are recognized and unfolded by a dedicated AAA+ ATPase (Mycobacterium proteasomal AAA+ ATPase; ATPase forming ring-shaped complexes). In Mycobacteria, degradation of pupylated proteins by the proteasome serves as a protection mechanism against several stress conditions. Other bacterial genera capable of pupylation such as Corynebacterium lack a proteasome, and the fate of pupylated proteins is unknown. We discovered that Corynebacterium glutamicum mutants lacking components of the pupylation machinery show a strong growth defect under iron limitation, which was caused by the absence of pupylation and unfolding of the iron storage protein ferritin. Genetic and biochemical data support a model in which the pupylation machinery is responsible for iron release from ferritin independent of degradation.

The pupylation machinery is involved in iron homeostasis by targeting the iron storage protein ferritin

PubMed Central

Küberl, Andreas; Polen, Tino; Bott, Michael

2016-01-01

The balance of sufficient iron supply and avoidance of iron toxicity by iron homeostasis is a prerequisite for cellular metabolism and growth. Here we provide evidence that, in Actinobacteria, pupylation plays a crucial role in this process. Pupylation is a posttranslational modification in which the prokaryotic ubiquitin-like protein Pup is covalently attached to a lysine residue in target proteins, thus resembling ubiquitination in eukaryotes. Pupylated proteins are recognized and unfolded by a dedicated AAA+ ATPase (Mycobacterium proteasomal AAA+ ATPase; ATPase forming ring-shaped complexes). In Mycobacteria, degradation of pupylated proteins by the proteasome serves as a protection mechanism against several stress conditions. Other bacterial genera capable of pupylation such as Corynebacterium lack a proteasome, and the fate of pupylated proteins is unknown. We discovered that Corynebacterium glutamicum mutants lacking components of the pupylation machinery show a strong growth defect under iron limitation, which was caused by the absence of pupylation and unfolding of the iron storage protein ferritin. Genetic and biochemical data support a model in which the pupylation machinery is responsible for iron release from ferritin independent of degradation. PMID:27078093

Structural Elements Regulating AAA+ Protein Quality Control Machines.

PubMed

Chang, Chiung-Wen; Lee, Sukyeong; Tsai, Francis T F

2017-01-01

Members of the ATPases Associated with various cellular Activities (AAA+) superfamily participate in essential and diverse cellular pathways in all kingdoms of life by harnessing the energy of ATP binding and hydrolysis to drive their biological functions. Although most AAA+ proteins share a ring-shaped architecture, AAA+ proteins have evolved distinct structural elements that are fine-tuned to their specific functions. A central question in the field is how ATP binding and hydrolysis are coupled to substrate translocation through the central channel of ring-forming AAA+ proteins. In this mini-review, we will discuss structural elements present in AAA+ proteins involved in protein quality control, drawing similarities to their known role in substrate interaction by AAA+ proteins involved in DNA translocation. Elements to be discussed include the pore loop-1, the Inter-Subunit Signaling (ISS) motif, and the Pre-Sensor I insert (PS-I) motif. Lastly, we will summarize our current understanding on the inter-relationship of those structural elements and propose a model how ATP binding and hydrolysis might be coupled to polypeptide translocation in protein quality control machines.

Arresting a Torsin ATPase Reshapes the Endoplasmic Reticulum*

PubMed Central

Rose, April E.; Zhao, Chenguang; Turner, Elizabeth M.; Steyer, Anna M.; Schlieker, Christian

2014-01-01

Torsins are membrane-tethered AAA+ ATPases residing in the nuclear envelope (NE) and endoplasmic reticulum (ER). Here, we show that the induction of a conditional, dominant-negative TorsinB variant provokes a profound reorganization of the endomembrane system into foci containing double membrane structures that are derived from the ER. These double-membrane sinusoidal structures are formed by compressing the ER lumen to a constant width of 15 nm, and are highly enriched in the ATPase activator LULL1. Further, we define an important role for a highly conserved aromatic motif at the C terminus of Torsins. Mutations in this motif perturb LULL1 binding, reduce ATPase activity, and profoundly limit the induction of sinusoidal structures. PMID:24275647

Conformational changes in the AAA ATPase p97–p47 adaptor complex

PubMed Central

Beuron, Fabienne; Dreveny, Ingrid; Yuan, Xuemei; Pye, Valerie E; Mckeown, Ciaran; Briggs, Louise C; Cliff, Matthew J; Kaneko, Yayoi; Wallis, Russell; Isaacson, Rivka L; Ladbury, John E; Matthews, Steve J; Kondo, Hisao; Zhang, Xiaodong; Freemont, Paul S

2006-01-01

The AAA+ATPase p97/VCP, helped by adaptor proteins, exerts its essential role in cellular events such as endoplasmic reticulum-associated protein degradation or the reassembly of Golgi, ER and the nuclear envelope after mitosis. Here, we report the three-dimensional cryo-electron microscopy structures at ∼20 Å resolution in two nucleotide states of the endogenous hexameric p97 in complex with a recombinant p47 trimer, one of the major p97 adaptor proteins involved in membrane fusion. Depending on the nucleotide state, we observe the p47 trimer to be in two distinct arrangements on top of the p97 hexamer. By combining the EM data with NMR and other biophysical measurements, we propose a model of ATP-dependent p97(N) domain motions that lead to a rearrangement of p47 domains, which could result in the disassembly of target protein complexes. PMID:16601695

Inter-ring rotations of AAA ATPase p97 revealed by electron cryomicroscopy

PubMed Central

Yeung, Heidi O.; Förster, Andreas; Bebeacua, Cecilia; Niwa, Hajime; Ewens, Caroline; McKeown, Ciarán; Zhang, Xiaodong; Freemont, Paul S.

2014-01-01

The type II AAA+ protein p97 is involved in numerous cellular activities, including endoplasmic reticulum-associated degradation, transcription activation, membrane fusion and cell-cycle control. These activities are at least in part regulated by the ubiquitin system, in which p97 is thought to target ubiquitylated protein substrates within macromolecular complexes and assist in their extraction or disassembly. Although ATPase activity is essential for p97 function, little is known about how ATP binding or hydrolysis is coupled with p97 conformational changes and substrate remodelling. Here, we have used single-particle electron cryomicroscopy (cryo-EM) to study the effect of nucleotides on p97 conformation. We have identified conformational heterogeneity within the cryo-EM datasets from which we have resolved two major p97 conformations. A comparison of conformations reveals inter-ring rotations upon nucleotide binding and hydrolysis that may be linked to the remodelling of target protein complexes. PMID:24598262

Sequential Actions of the AAA-ATPase Valosin-containing Protein (VCP)/p97 and the Proteasome 19 S Regulatory Particle in Sterol-accelerated, Endoplasmic Reticulum (ER)-associated Degradation of 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase*

PubMed Central

Morris, Lindsey L.; Hartman, Isamu Z.; Jun, Dong-Jae; Seemann, Joachim; DeBose-Boyd, Russell A.

2014-01-01

Accelerated endoplasmic reticulum (ER)-associated degradation (ERAD) of the cholesterol biosynthetic enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase results from its sterol-induced binding to ER membrane proteins called Insig-1 and Insig-2. This binding allows for subsequent ubiquitination of reductase by Insig-associated ubiquitin ligases. Once ubiquitinated, reductase becomes dislocated from ER membranes into the cytosol for degradation by 26 S proteasomes through poorly defined reactions mediated by the AAA-ATPase valosin-containing protein (VCP)/p97 and augmented by the nonsterol isoprenoid geranylgeraniol. Here, we report that the oxysterol 25-hydroxycholesterol and geranylgeraniol combine to trigger extraction of reductase across ER membranes prior to its cytosolic release. This conclusion was drawn from studies utilizing a novel assay that measures membrane extraction of reductase by determining susceptibility of a lumenal epitope in the enzyme to in vitro protease digestion. Susceptibility of the lumenal epitope to protease digestion and thus membrane extraction of reductase were tightly regulated by 25-hydroxycholesterol and geranylgeraniol. The reaction was inhibited by RNA interference-mediated knockdown of either Insigs or VCP/p97. In contrast, reductase continued to become membrane-extracted, but not cytosolically dislocated, in cells deficient for AAA-ATPases of the proteasome 19 S regulatory particle. These findings establish sequential roles for VCP/p97 and the 19 S regulatory particle in the sterol-accelerated ERAD of reductase that may be applicable to the ERAD of other substrates. PMID:24860107

Structure and evolution of N-domains in AAA metalloproteases.

PubMed

Scharfenberg, Franka; Serek-Heuberger, Justyna; Coles, Murray; Hartmann, Marcus D; Habeck, Michael; Martin, Jörg; Lupas, Andrei N; Alva, Vikram

2015-02-27

Metalloproteases of the AAA (ATPases associated with various cellular activities) family play a crucial role in protein quality control within the cytoplasmic membrane of bacteria and the inner membrane of eukaryotic organelles. These membrane-anchored hexameric enzymes are composed of an N-terminal domain with one or two transmembrane helices, a central AAA ATPase module, and a C-terminal Zn(2+)-dependent protease. While the latter two domains have been well studied, so far, little is known about the N-terminal regions. Here, in an extensive bioinformatic and structural analysis, we identified three major, non-homologous groups of N-domains in AAA metalloproteases. By far, the largest one is the FtsH-like group of bacteria and eukaryotic organelles. The other two groups are specific to Yme1: one found in plants, fungi, and basal metazoans and the other one found exclusively in animals. Using NMR and crystallography, we determined the subunit structure and hexameric assembly of Escherichia coli FtsH-N, exhibiting an unusual α+β fold, and the conserved part of fungal Yme1-N from Saccharomyces cerevisiae, revealing a tetratricopeptide repeat fold. Our bioinformatic analysis showed that, uniquely among these proteins, the N-domain of Yme1 from the cnidarian Hydra vulgaris contains both the tetratricopeptide repeat region seen in basal metazoans and a region of homology to the N-domains of animals. Thus, it is a modern-day representative of an intermediate in the evolution of animal Yme1 from basal eukaryotic precursors. Copyright © 2015. Published by Elsevier Ltd.

Unique ATPase site architecture triggers cis-mediated synchronized ATP binding in heptameric AAA+-ATPase domain of flagellar regulatory protein FlrC.

PubMed

Dey, Sanjay; Biswas, Maitree; Sen, Udayaditya; Dasgupta, Jhimli

2015-04-03

Bacterial enhancer-binding proteins (bEBPs) oligomerize through AAA(+) domains and use ATP hydrolysis-driven energy to isomerize the RNA polymerase-σ(54) complex during transcriptional initiation. Here, we describe the first structure of the central AAA(+) domain of the flagellar regulatory protein FlrC (FlrC(C)), a bEBP that controls flagellar synthesis in Vibrio cholerae. Our results showed that FlrC(C) forms heptamer both in nucleotide (Nt)-free and -bound states without ATP-dependent subunit remodeling. Unlike the bEBPs such as NtrC1 or PspF, a novel cis-mediated "all or none" ATP binding occurs in the heptameric FlrC(C), because constriction at the ATPase site, caused by loop L3 and helix α7, restricts the proximity of the trans-protomer required for Nt binding. A unique "closed to open" movement of Walker A, assisted by trans-acting "Glu switch" Glu-286, facilitates ATP binding and hydrolysis. Fluorescence quenching and ATPase assays on FlrC(C) and mutants revealed that although Arg-349 of sensor II, positioned by trans-acting Glu-286 and Tyr-290, acts as a key residue to bind and hydrolyze ATP, Arg-319 of α7 anchors ribose and controls the rate of ATP hydrolysis by retarding the expulsion of ADP. Heptameric state of FlrC(C) is restored in solution even with the transition state mimicking ADP·AlF3. Structural results and pulldown assays indicated that L3 renders an in-built geometry to L1 and L2 causing σ(54)-FlrC(C) interaction independent of Nt binding. Collectively, our results underscore a novel mechanism of ATP binding and σ(54) interaction that strives to understand the transcriptional mechanism of the bEBPs, which probably interact directly with the RNA polymerase-σ(54) complex without DNA looping. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

DDX3 DEAD-box RNA helicase plays a central role in mitochondrial protein quality control in Leishmania

PubMed Central

Padmanabhan, Prasad Kottayil; Zghidi-Abouzid, Ouafa; Samant, Mukesh; Dumas, Carole; Aguiar, Bruno Guedes; Estaquier, Jerome; Papadopoulou, Barbara

2016-01-01

DDX3 is a highly conserved member of ATP-dependent DEAD-box RNA helicases with multiple functions in RNA metabolism and cellular signaling. Here, we describe a novel function for DDX3 in regulating the mitochondrial stress response in the parasitic protozoan Leishmania. We show that genetic inactivation of DDX3 leads to the accumulation of mitochondrial reactive oxygen species (ROS) associated with a defect in hydrogen peroxide detoxification. Upon stress, ROS production is greatly enhanced, causing mitochondrial membrane potential loss, mitochondrial fragmentation, and cell death. Importantly, this phenotype is exacerbated upon oxidative stress in parasites forced to use the mitochondrial oxidative respiratory machinery. Furthermore, we show that in the absence of DDX3, levels of major components of the unfolded protein response as well as of polyubiquitinated proteins increase in the parasite, particularly in the mitochondrion, as an indicator of mitochondrial protein damage. Consistent with these findings, immunoprecipitation and mass-spectrometry studies revealed potential interactions of DDX3 with key components of the cellular stress response, particularly the antioxidant response, the unfolded protein response, and the AAA-ATPase p97/VCP/Cdc48, which is essential in mitochondrial protein quality control by driving proteosomal degradation of polyubiquitinated proteins. Complementation studies using DDX3 deletion mutants lacking conserved motifs within the helicase core support that binding of DDX3 to ATP is essential for DDX3's function in mitochondrial proteostasis. As a result of the inability of DDX3-depleted Leishmania to recover from ROS damage and to survive various stresses in the host macrophage, parasite intracellular development was impaired. Collectively, these observations support a central role for the Leishmania DDX3 homolog in preventing ROS-mediated damage and in maintaining mitochondrial protein quality control. PMID:27735940

Temporal global expression data reveal known and novel salicylate-impacted processes and regulators mediating powdery mildew growth and reproduction on Arabidopsis.

PubMed

Chandran, Divya; Tai, Yu Chuan; Hather, Gregory; Dewdney, Julia; Denoux, Carine; Burgess, Diane G; Ausubel, Frederick M; Speed, Terence P; Wildermuth, Mary C

2009-03-01

Salicylic acid (SA) is a critical mediator of plant innate immunity. It plays an important role in limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis (Arabidopsis thaliana). To investigate this later phase of the PM interaction and the role played by SA, we performed replicated global expression profiling for wild-type and SA biosynthetic mutant isochorismate synthase1 (ics1) Arabidopsis from 0 to 7 d after infection. We found that ICS1-impacted genes constitute 3.8% of profiled genes, with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T(2) statistic). Functional analyses of T(2)-selected genes identified statistically significant PM-impacted processes, including photosynthesis, cell wall modification, and alkaloid metabolism, that are ICS1 independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also support a role for ICS1 (SA) in iron and calcium homeostasis and identify components of SA cross talk with other phytohormones. Through our analysis, 39 novel PM-impacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2 (for plant ubiquitin regulatory X domain-containing protein 2), results in significantly reduced reproduction of the PM in a cell death-independent manner. Although little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48, an essential AAA-ATPase chaperone that mediates diverse cellular activities, including homotypic fusion of endoplasmic reticulum and Golgi membranes, endoplasmic reticulum-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance.

Characterization of Synthetic-Lethal Mutants Reveals a Role for the Saccharomyces Cerevisiae Guanine-Nucleotide Exchange Factor Cdc24p in Vacuole Function and Na(+) Tolerance

PubMed Central

White, W. H.; Johnson, D. I.

1997-01-01

Cdc24p is the guanine-nucleotide exchange factor for the Cdc42p GTPase, which controls cell polarity in Saccharomyces cerevisiae. To identify new genes that may affect cell polarity, we characterized six UV-induced csl (CDC24 synthetic-lethal) mutants that exhibited synthetic-lethality with cdc24-4(ts) at 23°. Five mutants were not complemented by plasmid-borne CDC42, RSR1, BUD5, BEM1, BEM2, BEM3 or CLA4 genes, which are known to play a role in cell polarity. The csl3 mutant displayed phenotypes similar to those observed with calcium-sensitive, Pet(-) vma mutants defective in vacuole function. CSL5 was allelic to VMA5, the vacuolar H(+)-ATPase subunit C, and one third of csl5 cdc24-4(ts) cells were elongated or had misshapen buds. A cdc24-4(ts) Δvma5::LEU2 double mutant did not exhibit synthetic lethality, suggesting that the csl5/vma5 cdc24-4(ts) synthetic-lethality was not simply due to altered vacuole function. The cdc24-4(ts) mutant, like Δvma5::LEU2 and csl3 mutants, was sensitive to high levels of Ca(2+) as well as Na(+) in the growth media, which did not appear to be a result of a fragile cell wall because the phenotypes were not remedied by 1 M sorbitol. Our results indicated that Cdc24p was required in one V-ATPase mutant and another mutant affecting vacuole morphology, and also implicated Cdc24p in Na(+) tolerance. PMID:9286667

UCS protein Rng3p activates actin filament gliding by fission yeast myosin-II

PubMed Central

Lord, Matthew; Pollard, Thomas D.

2004-01-01

We purified native Myo2p/Cdc4p/Rlc1p (Myo2), the myosin-II motor required for cytokinesis by Schizosaccharomyces pombe. The Myo2p heavy chain associates with two light chains, Cdc4p and Rlc1p. Although crude Myo2 supported gliding motility of actin filaments in vitro, purified Myo2 lacked this activity in spite of retaining full Ca-ATPase activity and partial actin-activated Mg-ATPase activity. Unc45-/Cro1p-/She4p-related (UCS) protein Rng3p restored the full motility and actin-activated Mg-ATPase activity of purified Myo2. The COOH-terminal UCS domain of Rng3p alone restored motility to pure Myo2. Thus, Rng3p contributes directly to the motility activity of native Myo2. Consistent with a role in Myo2 activation, Rng3p colocalizes with Myo2p in the cytokinetic contractile ring. The absence of Rlc1p or mutations in the Myo2p head or Rng3p compromise the in vitro motility of Myo2 and explain the defects in cytokinesis associated with some of these mutations. In contrast, Myo2 with certain temperature-sensitive forms of Cdc4p has normal motility, so these mutations compromise other functions of Cdc4p required for cytokinesis. PMID:15504913

Archaeal MCM has separable processivity, substrate choice and helicase domains

PubMed Central

Barry, Elizabeth R.; McGeoch, Adam T.; Kelman, Zvi; Bell, Stephen D.

2007-01-01

The mini-chromosome maintenance (MCM) complex is the principal candidate for the replicative helicase of archaea and eukaryotes. Here, we describe a functional dissection of the roles of the three principal structural modules of the homomultimeric MCM of the hyperthermophilic archaeon Sulfolobus solfataricus. Our results include the first analysis of the central AAA+ domain in isolation. This domain possesses ATPase and helicase activity, defining this as the minimal helicase domain. Reconstitution experiments show that the helicase activity of the AAA+ domain can be stimulated by addition of the isolated N-terminal half in trans. Addition of the N-terminus influences both the processivity of the helicase and the choice of substrate that can be melted by the ATPase domain. The degenerate helix-turn-helix domain at the C-terminus of MCM exerts a negative effect on the helicase activity of the complex. These results provide the first evidence for extensive regulatory inter-domain communication within the MCM complex. PMID:17259218

The AAA+ ATPase p97, a cellular multitool

PubMed Central

Stach, Lasse

2017-01-01

The AAA+ (ATPases associated with diverse cellular activities) ATPase p97 is essential to a wide range of cellular functions, including endoplasmic reticulum-associated degradation, membrane fusion, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation and chromatin-associated processes, which are regulated by ubiquitination. p97 acts downstream from ubiquitin signaling events and utilizes the energy from ATP hydrolysis to extract its substrate proteins from cellular structures or multiprotein complexes. A multitude of p97 cofactors have evolved which are essential to p97 function. Ubiquitin-interacting domains and p97-binding domains combine to form bi-functional cofactors, whose complexes with p97 enable the enzyme to interact with a wide range of ubiquitinated substrates. A set of mutations in p97 have been shown to cause the multisystem proteinopathy inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia. In addition, p97 inhibition has been identified as a promising approach to provoke proteotoxic stress in tumors. In this review, we will describe the cellular processes governed by p97, how the cofactors interact with both p97 and its ubiquitinated substrates, p97 enzymology and the current status in developing p97 inhibitors for cancer therapy. PMID:28819009

Structural pathway of regulated substrate transfer and threading through an Hsp100 disaggregase.

PubMed

Deville, Célia; Carroni, Marta; Franke, Kamila B; Topf, Maya; Bukau, Bernd; Mogk, Axel; Saibil, Helen R

2017-08-01

Refolding aggregated proteins is essential in combating cellular proteotoxic stress. Together with Hsp70, Hsp100 chaperones, including Escherichia coli ClpB, form a powerful disaggregation machine that threads aggregated polypeptides through the central pore of tandem adenosine triphosphatase (ATPase) rings. To visualize protein disaggregation, we determined cryo-electron microscopy structures of inactive and substrate-bound ClpB in the presence of adenosine 5'- O -(3-thiotriphosphate), revealing closed AAA+ rings with a pronounced seam. In the substrate-free state, a marked gradient of resolution, likely corresponding to mobility, spans across the AAA+ rings with a dynamic hotspot at the seam. On the seam side, the coiled-coil regulatory domains are locked in a horizontal, inactive orientation. On the opposite side, the regulatory domains are accessible for Hsp70 binding, substrate targeting, and activation. In the presence of the model substrate casein, the polypeptide threads through the entire pore channel and increased nucleotide occupancy correlates with higher ATPase activity. Substrate-induced domain displacements indicate a pathway of regulated substrate transfer from Hsp70 to the ClpB pore, inside which a spiral of loops contacts the substrate. The seam pore loops undergo marked displacements, along with ordering of the regulatory domains. These asymmetric movements suggest a mechanism for ATPase activation and substrate threading during disaggregation.

Regulatory coiled-coil domains promote head-to-head assemblies of AAA+ chaperones essential for tunable activity control.

PubMed

Carroni, Marta; Franke, Kamila B; Maurer, Michael; Jäger, Jasmin; Hantke, Ingo; Gloge, Felix; Linder, Daniela; Gremer, Sebastian; Turgay, Kürşad; Bukau, Bernd; Mogk, Axel

2017-11-22

Ring-forming AAA+ chaperones exert ATP-fueled substrate unfolding by threading through a central pore. This activity is potentially harmful requiring mechanisms for tight repression and substrate-specific activation. The AAA+ chaperone ClpC with the peptidase ClpP forms a bacterial protease essential to virulence and stress resistance. The adaptor MecA activates ClpC by targeting substrates and stimulating ClpC ATPase activity. We show how ClpC is repressed in its ground state by determining ClpC cryo-EM structures with and without MecA. ClpC forms large two-helical assemblies that associate via head-to-head contacts between coiled-coil middle domains (MDs). MecA converts this resting state to an active planar ring structure by binding to MD interaction sites. Loss of ClpC repression in MD mutants causes constitutive activation and severe cellular toxicity. These findings unravel an unexpected regulatory concept executed by coiled-coil MDs to tightly control AAA+ chaperone activity.

Katanin spiral and ring structures shed light on power stroke for microtubule severing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zehr, Elena; Szyk, Agnieszka; Piszczek, Grzegorz

Microtubule-severing enzymes katanin, spastin and fidgetin are AAA ATPases critical for the biogenesis and maintenance of complex microtubule arrays in axons, spindles and cilia. Because of a lack of 3D structures, their mechanism has remained poorly understood. We report the first X-ray structure of the monomeric AAA katanin module and cryo-EM reconstructions of the hexamer in two conformations. These reveal an unexpected asymmetric arrangement of the AAA domains mediated by structural elements unique to severing enzymes and critical for their function. Our reconstructions show that katanin cycles between open spiral and closed ring conformations, depending on the ATP occupancy ofmore » a gating protomer that tenses or relaxes inter-protomer interfaces. Cycling of the hexamer between these conformations would provide the power stroke for microtubule severing.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiraishi, Nobuhiro; Ishida, Yo-ichi; Nagahama, Masami, E-mail: nagahama@my-pharm.ac.jp

Nuclear VCP-like 2 (NVL2) is a chaperone-like nucleolar ATPase of the AAA (ATPase associated with diverse cellular activities) family, which exhibits a high level of amino acid sequence similarity with the cytosolic AAA-ATPase VCP/p97. These proteins generally act on macromolecular complexes to stimulate energy-dependent release of their constituents. We previously showed that NVL2 interacts with RNA processing/degradation machinery containing an RNA helicase MTR4/DOB1 and an exonuclease complex, nuclear exosome, and involved in the biogenesis of 60S ribosomal subunits. These observations implicate NVL2 as a remodeling factor for the MTR4-exosome complex during the maturation of pre-ribosomal particles. Here, we used amore » proteomic screen and identified a WD repeat-containing protein 74 (WDR74) as a factor that specifically dissociates from this complex depending on the ATPase activity of NVL2. WDR74 shows weak amino acid sequence similarity with the yeast ribosome biogenesis protein Nsa1 and is co-localized with NVL2 in the nucleolus. Knockdown of WDR74 decreases 60S ribosome levels. Taken together, our results suggest that WDR74 is a novel regulatory protein of the MTR4-exsosome complex whose interaction is regulated by NVL2 and is involved in ribosome biogenesis. - Highlights: • WDR74 accumulates in MTR4-exosome complex upon expression of dominant-negative NVL2. • WDR74 is co-localized with NVL2 in the nucleolus. • WDR74, along with NVL2, is involved in the synthesis of 60S ribosomal subunits.« less

ATAD3 proteins: brokers of a mitochondria-endoplasmic reticulum connection in mammalian cells.

PubMed

Baudier, Jacques

2018-05-01

In yeast, a sequence of physical and genetic interactions termed the endoplasmic reticulum (ER)-mitochondria organizing network (ERMIONE) controls mitochondria-ER interactions and mitochondrial biogenesis. Several functions that characterize ERMIONE complexes are conserved in mammalian cells, suggesting that a similar tethering complex must exist in metazoans. Recent studies have identified a new family of nuclear-encoded ATPases associated with diverse cellular activities (AAA+-ATPase) mitochondrial membrane proteins specific to multicellular eukaryotes, called the ATPase family AAA domain-containing protein 3 (ATAD3) proteins (ATAD3A and ATAD3B). These proteins are crucial for normal mitochondrial-ER interactions and lie at the heart of processes underlying mitochondrial biogenesis. ATAD3A orthologues have been studied in flies, worms, and mammals, highlighting the widespread importance of this gene during embryonic development and in adulthood. ATAD3A is a downstream effector of target of rapamycin (TOR) signalling in Drosophila and exhibits typical features of proteins from the ERMIONE-like complex in metazoans. In humans, mutations in the ATAD3A gene represent a new link between altered mitochondrial-ER interaction and recognizable neurological syndromes. The primate-specific ATAD3B protein is a biomarker of pluripotent embryonic stem cells. Through negative regulation of ATAD3A function, ATAD3B supports mitochondrial stemness properties. © 2017 Cambridge Philosophical Society.

The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects

PubMed Central

Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A.

2016-01-01

Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. PMID:27257060

ATAD2 is an epigenetic reader of newly synthesized histone marks during DNA replication.

PubMed

Koo, Seong Joo; Fernández-Montalván, Amaury E; Badock, Volker; Ott, Christopher J; Holton, Simon J; von Ahsen, Oliver; Toedling, Joern; Vittori, Sarah; Bradner, James E; Gorjánácz, Mátyás

2016-10-25

ATAD2 (ATPase family AAA domain-containing protein 2) is a chromatin regulator harboring an AAA+ ATPase domain and a bromodomain, previously proposed to function as an oncogenic transcription co-factor. Here we suggest that ATAD2 is also required for DNA replication. ATAD2 is co-expressed with genes involved in DNA replication in various cancer types and predominantly expressed in S phase cells where it localized on nascent chromatin (replication sites). Our extensive biochemical and cellular analyses revealed that ATAD2 is recruited to replication sites through a direct interaction with di-acetylated histone H4 at K5 and K12, indicative of newly synthesized histones during replication-coupled chromatin reassembly. Similar to ATAD2-depletion, ectopic expression of ATAD2 mutants that are deficient in binding to these di-acetylation marks resulted in reduced DNA replication and impaired loading of PCNA onto chromatin, suggesting relevance of ATAD2 in DNA replication. Taken together, our data show a novel function of ATAD2 in cancer and for the first time identify a reader of newly synthesized histone di-acetylation-marks during replication.

Molecular insights into the m-AAA protease-mediated dislocation of transmembrane helices in the mitochondrial inner membrane.

PubMed

Lee, Seoeun; Lee, Hunsang; Yoo, Suji; Kim, Hyun

2017-12-08

Protein complexes involved in respiration, ATP synthesis, and protein import reside in the mitochondrial inner membrane; thus, proper regulation of these proteins is essential for cell viability. The m -AAA protease, a conserved hetero-hexameric AAA (ATPase associated with diverse cellular activities) protease, composed of the Yta10 and Yta12 proteins, regulates mitochondrial proteostasis by mediating protein maturation and degradation. It also recognizes and mediates the dislocation of membrane-embedded substrates, including foreign transmembrane (TM) segments, but the molecular mechanism involved in these processes remains elusive. This study investigated the role of the TM domains in the m -AAA protease by systematic replacement of one TM domain at a time in yeast. Our data indicated that replacement of the Yta10 TM2 domain abolishes membrane dislocation for only a subset of substrates, whereas replacement of the Yta12 TM2 domain impairs membrane dislocation for all tested substrates, suggesting different roles of the TM domains in each m -AAA protease subunit. Furthermore, m -AAA protease-mediated membrane dislocation was impaired in the presence of a large downstream hydrophilic moiety in a membrane substrate. This finding suggested that the m -AAA protease cannot dislocate large hydrophilic domains across the membrane, indicating that the membrane dislocation probably occurs in a lipid environment. In summary, this study highlights previously underappreciated biological roles of TM domains of the m -AAA proteases in mediating the recognition and dislocation of membrane-embedded substrates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Electron cryomicroscopy structure of a membrane-anchored mitochondrial AAA protease.

PubMed

Lee, Sukyeong; Augustin, Steffen; Tatsuta, Takashi; Gerdes, Florian; Langer, Thomas; Tsai, Francis T F

2011-02-11

FtsH-related AAA proteases are conserved membrane-anchored, ATP-dependent molecular machines, which mediate the processing and turnover of soluble and membrane-embedded proteins in eubacteria, mitochondria, and chloroplasts. Homo- and hetero-oligomeric proteolytic complexes exist, which are composed of homologous subunits harboring an ATPase domain of the AAA family and an H41 metallopeptidase domain. Mutations in subunits of mitochondrial m-AAA proteases have been associated with different neurodegenerative disorders in human, raising questions on the functional differences between homo- and hetero-oligomeric AAA proteases. Here, we have analyzed the hetero-oligomeric yeast m-AAA protease composed of homologous Yta10 and Yta12 subunits. We combined genetic and structural approaches to define the molecular determinants for oligomer assembly and to assess functional similarities between Yta10 and Yta12. We demonstrate that replacement of only two amino acid residues within the metallopeptidase domain of Yta12 allows its assembly into homo-oligomeric complexes. To provide a molecular explanation, we determined the 12 Å resolution structure of the intact yeast m-AAA protease with its transmembrane domains by electron cryomicroscopy (cryo-EM) and atomic structure fitting. The full-length m-AAA protease has a bipartite structure and is a hexamer in solution. We found that residues in Yta12, which facilitate homo-oligomerization when mutated, are located at the interface between neighboring protomers in the hexamer ring. Notably, the transmembrane and intermembrane space domains are separated from the main body, creating a passage on the matrix side, which is wide enough to accommodate unfolded but not folded polypeptides. These results suggest a mechanism regarding how proteins are recognized and degraded by m-AAA proteases.

Comparative analysis of expression of two p97 homologues in Caenorhabditis elegans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamauchi, Seiji; Yamanaka, Kunitoshi; Ogura, Teru

2006-06-30

Caenorhabditis elegans possesses two p97/VCP/Cdc48p homologues, named CDC-48.1 (C06A1.1) and CDC-48.2 (C41C4.8), although their expression regulation and functional diversity have not yet been studied. We therefore investigated spatial and temporal expression patterns of two p97 homologues in this study. RT-PCR and Western blot analysis showed that the amount of cdc-48.1 was about twofold of that of cdc-48.2 in adults and that two p97 homologues were induced by ER stress. The amount of cdc-48.1 mRNA did not increase in the cdc-48.2 deletion mutant and vice versa. In situ hybridization showed that two p97 homologues are mainly expressed in germ cells. Inmore » vivo expression analysis by using GFP translational fusion constructs revealed that CDC-48.1::GFP was expressed from embryos through to adult worms, while CDC-48.2::GFP was expressed mainly in embryos. These results suggest that the expression of two p97 homologues of C. elegans is differently regulated and independent of each other.« less

Atomic resolution x-ray structure of the substrate recognition domain of higher plant rubisco activase

USDA-ARS?s Scientific Manuscript database

The rapid release of tight-binding inhibitors from dead-end Rubisco complexes requires the activity of Rubisco activase, an AAA+ ATPase that utilizes chemo-mechanical energy to catalyze the reactivation of Rubisco. Activase is thought to play a central role in coordinating the rate of CO2 fixation w...

The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects.

PubMed

Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A

2016-09-19

Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Cdc48 regulates a deubiquitylase cascade critical for mitochondrial fusion

PubMed Central

den Brave, Fabian

2018-01-01

Cdc48/p97, a ubiquitin-selective chaperone, orchestrates the function of E3 ligases and deubiquitylases (DUBs). Here, we identify a new function of Cdc48 in ubiquitin-dependent regulation of mitochondrial dynamics. The DUBs Ubp12 and Ubp2 exert opposing effects on mitochondrial fusion and cleave different ubiquitin chains on the mitofusin Fzo1. We demonstrate that Cdc48 integrates the activities of these two DUBs, which are themselves ubiquitylated. First, Cdc48 promotes proteolysis of Ubp12, stabilizing pro-fusion ubiquitylation on Fzo1. Second, loss of Ubp12 stabilizes Ubp2 and thereby facilitates removal of ubiquitin chains on Fzo1 inhibiting fusion. Thus, Cdc48 synergistically regulates the ubiquitylation status of Fzo1, allowing to control the balance between activation or repression of mitochondrial fusion. In conclusion, we unravel a new cascade of ubiquitylation events, comprising Cdc48 and two DUBs, fine-tuning the fusogenic activity of Fzo1. PMID:29309037

The Cdc48 Protein and Its Cofactor Vms1 Are Involved in Cdc13 Protein Degradation*

PubMed Central

Baek, Guem Hee; Cheng, Haili; Kim, Ikjin; Rao, Hai

2012-01-01

Vms1 is a newly identified Cdc48-binding protein. The biological function of Vms1 remains obscure. Here, we show that both Cdc48 and Vms1, but not Cdc48 cofactors Ufd1 and Ufd2, are crucial for the degradation of Cdc13, a telomere regulator. Interestingly, both autophagy and the proteasome are involved in Cdc13 turnover. Toxicity associated with accumulation of large amounts of Cdc13 in vms1Δ or autophagy mutants underscores the significance of the proteolytic regulation of Cdc13. Because few ubiquitylated yeast proteins are known to be degraded by autophagy under non-stress conditions, the identification of Cdc13 as a target of autophagy provides a valuable tool to unravel the mechanism of autophagy-mediated selective protein degradation. PMID:22718752

The AAA+ ATPase TRIP13 remodels HORMA domains through N-terminal engagement and unfolding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Qiaozhen; Kim, Dong Hyun; Dereli, Ihsan

Proteins of the conserved HORMA domain family, including the spindle assembly checkpoint protein MAD2 and the meiotic HORMADs, assemble into signaling complexes by binding short peptides termed “closure motifs”. The AAA+ ATPase TRIP13 regulates both MAD2 and meiotic HORMADs by disassembling these HORMA domain–closure motif complexes, but its mechanisms of substrate recognition and remodeling are unknown. Here, we combine X-ray crystallography and crosslinking mass spectrometry to outline how TRIP13 recognizes MAD2 with the help of the adapter protein p31comet. We show that p31comet binding to the TRIP13 N-terminal domain positions the disordered MAD2 N-terminus for engagement by the TRIP13 “poremore » loops”, which then unfold MAD2 in the presence of ATP. N-terminal truncation of MAD2 renders it refractory to TRIP13 action in vitro, and in cells causes spindle assembly checkpoint defects consistent with loss of TRIP13 function. Similar truncation of HORMAD1 in mouse spermatocytes compromises its TRIP13-mediated removal from meiotic chromosomes, highlighting a conserved mechanism for recognition and disassembly of HORMA domain–closure motif complexes by TRIP13.« less

K11- and K48-Linked Ubiquitin Chains Interact with p97 during Endoplasmic Reticulum-Associated Degradation

PubMed Central

Locke, Matthew; Toth, Julia I.; Petroski, Matthew D.

2014-01-01

The AAA+ ATPase p97 has a critical function in the cytoplasmic degradation of proteins misfolded in the endoplasmic reticulum through a mechanism known as ER-associated degradation (ERAD). During this process, p97 binds polyubiquitinated ERAD substrates and couples ATP hydrolysis to their dislocation from the ER as a prerequisite to destruction by the proteasome. The ubiquitin signals important for this process are not fully understood. Here we report that p97 interacts with lysine 11 (K11) and K48-linked ubiquitin polymers, but not those containing K63 linkages. Disruption of p97 through siRNA-mediated depletion, dominant negative over-expression, or chemical inhibition results in the accumulation of K11 and K48 ubiquitin chains predominantly at the ER membrane, and is associated with ER stress induction. We show that a catalytically inactive deubiquitinating enzyme and p97 cofactor YOD1 enhances the accumulation of K11- and K48-linked polyubiquitin in the cytoplasm, at the ER membrane, and bound to p97. In addition to general effects on p97-associated ubiquitin polymers, the ERAD substrate CD3δ is modified with both K11- and K48-ubiquitin chains prior to p97-dependent dislocation. Collectively, our data are consistent with a major role for p97 in the recognition of K11 and K48 polyubiquitinated proteins prior to their degradation by the proteasome. PMID:24417208

The I domain of the AAA+ HslUV protease coordinates substrate binding, ATP hydrolysis, and protein degradation

PubMed Central

Sundar, Shankar; Baker, Tania A; Sauer, Robert T

2012-01-01

In the AAA+ HslUV protease, substrates are bound and unfolded by a ring hexamer of HslU, before translocation through an axial pore and into the HslV degradation chamber. Here, we show that the N-terminal residues of an Arc substrate initially bind in the HslU axial pore, with key contacts mediated by a pore loop that is highly conserved in all AAA+ unfoldases. Disordered loops from the six intermediate domains of the HslU hexamer project into a funnel-shaped cavity above the pore and are positioned to contact protein substrates. Mutations in these I-domain loops increase KM and decrease Vmax for degradation, increase the mobility of bound substrates, and prevent substrate stimulation of ATP hydrolysis. HslU-ΔI has negligible ATPase activity. Thus, the I domain plays an active role in coordinating substrate binding, ATP hydrolysis, and protein degradation by the HslUV proteolytic machine. PMID:22102327

Structure and Biochemical Activities of Escherichia coli MgsA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Page, Asher N.; George, Nicholas P.; Marceau, Aimee H.

2012-02-27

Bacterial 'maintenance of genome stability protein A' (MgsA) and related eukaryotic enzymes play important roles in cellular responses to stalled DNA replication processes. Sequence information identifies MgsA enzymes as members of the clamp loader clade of AAA{sup +} proteins, but structural information defining the family has been limited. Here, the x-ray crystal structure of Escherichia coli MgsA is described, revealing a homotetrameric arrangement for the protein that distinguishes it from other clamp loader clade AAA{sup +} proteins. Each MgsA protomer is composed of three elements as follows: ATP-binding and helical lid domains (conserved among AAA{sup +} proteins) and a tetramerizationmore » domain. Although the tetramerization domains bury the greatest amount of surface area in the MgsA oligomer, each of the domains participates in oligomerization to form a highly intertwined quaternary structure. Phosphate is bound at each AAA{sup +} ATP-binding site, but the active sites do not appear to be in a catalytically competent conformation due to displacement of Arg finger residues. E. coli MgsA is also shown to form a complex with the single-stranded DNA-binding protein through co-purification and biochemical studies. MgsA DNA-dependent ATPase activity is inhibited by single-stranded DNA-binding protein. Together, these structural and biochemical observations provide insights into the mechanisms of MgsA family AAA{sup +} proteins.« less

Structure and Biochemical Activities of Escherichia coli MgsA*♦

PubMed Central

Page, Asher N.; George, Nicholas P.; Marceau, Aimee H.; Cox, Michael M.; Keck, James L.

2011-01-01

Bacterial “maintenance of genome stability protein A” (MgsA) and related eukaryotic enzymes play important roles in cellular responses to stalled DNA replication processes. Sequence information identifies MgsA enzymes as members of the clamp loader clade of AAA+ proteins, but structural information defining the family has been limited. Here, the x-ray crystal structure of Escherichia coli MgsA is described, revealing a homotetrameric arrangement for the protein that distinguishes it from other clamp loader clade AAA+ proteins. Each MgsA protomer is composed of three elements as follows: ATP-binding and helical lid domains (conserved among AAA+ proteins) and a tetramerization domain. Although the tetramerization domains bury the greatest amount of surface area in the MgsA oligomer, each of the domains participates in oligomerization to form a highly intertwined quaternary structure. Phosphate is bound at each AAA+ ATP-binding site, but the active sites do not appear to be in a catalytically competent conformation due to displacement of Arg finger residues. E. coli MgsA is also shown to form a complex with the single-stranded DNA-binding protein through co-purification and biochemical studies. MgsA DNA-dependent ATPase activity is inhibited by single-stranded DNA-binding protein. Together, these structural and biochemical observations provide insights into the mechanisms of MgsA family AAA+ proteins. PMID:21297161

ADPase activity of recombinantly expressed thermotolerant ATPases may be caused by copurification of adenylate kinase of Escherichia coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Baoyu; Sysoeva, Tatyana A.; Chowdhury, Saikat

2009-10-06

Except for apyrases, ATPases generally target only the {gamma}-phosphate of a nucleotide. Some non-apyrase ATPases from thermophilic microorganisms are reported to hydrolyze ADP as well as ATP, which has been described as a novel property of the ATPases from extreme thermophiles. Here, we describe an apparent ADP hydrolysis by highly purified preparations of the AAA+ ATPase NtrC1 from an extremely thermophilic bacterium, Aquifex aeolicus. This activity is actually a combination of the activities of the ATPase and contaminating adenylate kinase (AK) from Escherichia coli, which is present at 1/10 000 of the level of the ATPase. AK catalyzes conversion ofmore » two molecules of ADP into AMP and ATP, the latter being a substrate for the ATPase. We raise concern that the observed thermotolerance of E. coli AK and its copurification with thermostable proteins by commonly used methods may confound studies of enzymes that specifically catalyze hydrolysis of nucleoside diphosphates or triphosphates. For example, contamination with E. coli AK may be responsible for reported ADPase activities of the ATPase chaperonins from Pyrococcus furiosus, Pyrococcus horikoshii, Methanococcus jannaschii and Thermoplasma acidophilum; the ATP/ADP-dependent DNA ligases from Aeropyrum pernix K1 and Staphylothermus marinus; or the reported ATP-dependent activities of ADP-dependent phosphofructokinase of P. furiosus. Purification methods developed to separate NtrC1 ATPase from AK also revealed two distinct forms of the ATPase. One is tightly bound to ADP or GDP and able to bind to Q but not S ion exchange matrixes. The other is nucleotide-free and binds to both Q and S ion exchange matrixes.« less

In Search of a Cure for Proteostasis-Addicted Cancer: A AAA Target Revealed.

PubMed

Xia, Di; Ye, Yihong

2015-11-09

Tumorigenesis is often associated with an unbalanced protein homeostasis (proteostasis) network, which sensitizes cancer cells to drugs targeting protein quality control (PQC) regulators. In this issue of Cancer Cell, Anderson and colleagues investigated the anti-cancer activity of a new class of inhibitor against a multi-functional ATPase essential for proteostasis maintenance. Copyright © 2015 Elsevier Inc. All rights reserved.

The major-effect quantitative trait locus CsARN6.1 encodes an AAA ATPase domain-containing protein that is associated with waterlogging stress tolerance by promoting adventitious root formation

USDA-ARS?s Scientific Manuscript database

In plants, the formation of hypocotyl-derived adventitious roots (AR) is an important morphological acclimation to waterlogging stress, but its genetic basis is largely unknown. In the present study, with combined use of bulked segregant analysis-based high throughput next-gen whole genome sequencin...

Editor's Choice - Prolonged ICU Length of Stay after AAA Repair: Analysis of Time Trends and Long-term Outcome.

PubMed

Gavali, H; Mani, K; Tegler, G; Kawati, R; Covaciu, L; Wanhainen, A

2017-08-01

The aim of the study was to investigate the frequency and outcome of prolonged intensive care unit (ICU) length of stay (LOS) after abdominal aortic aneurysm (AAA) repair in the endovascular era. All patients operated on for AAA between 1999 and 2013 at Uppsala University hospital were identified. Data were retrieved from the Swedish Vascular registry, the Swedish Intensive Care registry, the National Population registry, and case records. Prolonged ICU LOS was defined as ≥ 48 h during the primary hospital stay. Patients surviving ≥ 48 h after AAA surgery were included in the analysis. A total of 725 patients were identified, of whom 707 (97.5%) survived ≥ 48 h; 563 (79.6%) underwent intact AAA repair and 144 (20.4%) ruptured AAA repair. A total of 548 patients (77.5%) required < 48 h of intensive care, 115 (16.3%) 2-6 days and 44 (6.2%) ≥ 7 days. The rate of prolonged ICU LOS declined considerably over time, from 41.4% of all AAA repairs in 1999 to 7.3% in 2013 (p < .001) whereas the use of endovascular aortic repair (EVAR) increased from 6.9% in 1999 to 78.0% in 2013 (p < .001). The 30 day survival rate was 98.2% for those with < 48 h ICU stay versus 93.0% for 2-6 days versus 81.8% for ≥ 7 days (p < .001); the corresponding 90 day survival was 97.1% versus 86.1% versus 63.6% (p < .001) respectively. For patients surviving 90 days after repair, there was no difference in long-term survival between the groups. During the period of progressively increasing use of EVAR, a simultaneous significant reduction in frequency of prolonged ICU LOS occurred. Although prolonged ICU LOS was associated with a high short-term mortality, long-term outcome among those surviving the initial 90 days was less affected. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Nucleotide-dependent assembly of the peroxisomal receptor export complex

PubMed Central

Grimm, Immanuel; Saffian, Delia; Girzalsky, Wolfgang; Erdmann, Ralf

2016-01-01

Pex1p and Pex6p are two AAA-ATPases required for biogenesis of peroxisomes. Both proteins form a hetero-hexameric complex in an ATP-dependent manner, which has a dual localization in the cytosol and at the peroxisomal membrane. At the peroxisomal membrane, the complex is responsible for the release of the import receptor Pex5p at the end of the matrix protein import cycle. In this study, we analyzed the recruitment of the AAA-complex to its anchor protein Pex15p at the peroxisomal membrane. We show that the AAA-complex is properly assembled even under ADP-conditions and is able to bind efficiently to Pex15p in vivo. We reconstituted binding of the Pex1/6p-complex to Pex15p in vitro and show that Pex6p mediates binding to the cytosolic part of Pex15p via a direct interaction. Analysis of the isolated complex revealed a stoichiometry of Pex1p/Pex6p/Pex15p of 3:3:3, indicating that each Pex6p molecule of the AAA-complex binds Pex15p. Binding of the AAA-complex to Pex15p in particular and to the import machinery in general is stabilized when ATP is bound to the second AAA-domain of Pex6p and its hydrolysis is prevented. The data indicate that receptor release in peroxisomal protein import is associated with a nucleotide-depending Pex1/6p-cycle of Pex15p-binding and release. PMID:26842748

Interaction between the AAA ATPase p97/VCP and a concealed UBX domain in the copper transporter ATP7A is associated with motor neuron degeneration.

PubMed

Yi, Ling; Kaler, Stephen G

2018-05-18

The copper-transporting ATPase ATP7A contains eight transmembrane domains and is required for normal human copper homeostasis. Mutations in the ATP7A gene may lead to infantile-onset cerebral degeneration (Menkes disease); occipital horn syndrome (OHS), a related but much milder illness; or an adult-onset isolated distal motor neuropathy. The ATP7A missense mutation T994I is located in the sixth transmembrane domain of ATP7A, represents one of the variants associated with the latter phenotype, and is associated with an abnormal interaction with p97/valosin-containing protein (VCP), a hexameric AAA ATPase (ATPase associated with diverse cellular activities) with multiple biological functions. In this study, we further characterized this interaction and discovered a concealed UBX domain in the third lumenal loop of ATP7A, between its fifth and sixth transmembrane domains. We show that the T994I substitution results in conformational exposure of the UBX domain, which then binds the N-terminal domain of p97/VCP. We also show that this abnormal interaction occurs at or near the cell plasma membrane. The UBX domain has a conserved hydrophobic FP (Phe-Pro) motif, and substitution with di-alanine abrogated the interaction and restored the proper intracellular localization of ATP7A in the trans -Golgi network. Using protein MS, we identified potential coordinating components of the ATP7A T994I -p97 complex, including NSFL1 cofactor (NSF1C or p47) that may be relevant to the pathophysiology and clinical effects associated with ATP7A T994I Our study represents the first report of p97/VCP binding to a UBX domain that is not normally exposed, resulting in an aberrant protein-protein interaction leading to motor neuron degeneration.

Crystal Structure of the Eukaryotic Origin Recognition Complex

PubMed Central

Bleichert, Franziska; Botchan, Michael R.; Berger, James M.

2015-01-01

Initiation of cellular DNA replication is tightly controlled to sustain genomic integrity. In eukaryotes, the heterohexameric origin recognition complex (ORC) is essential for coordinating replication onset. The 3.5 Å resolution crystal structure of Drosophila ORC reveals that the 270 kDa initiator core complex comprises a two-layered notched ring in which a collar of winged-helix domains from the Orc1-5 subunits sits atop a layer of AAA+ ATPase folds. Although canonical inter-AAA+ domain interactions exist between four of the six ORC subunits, unanticipated features are also evident, including highly interdigitated domain-swapping interactions between the winged-helix folds and AAA+ modules of neighboring protomers, and a quasi-spiral arrangement of DNA binding elements that circumnavigate a ~20 Å wide channel in the center of the complex. Comparative analyses indicate that ORC encircles DNA, using its winged-helix domain face to engage the MCM2-7 complex during replicative helicase loading; however, an observed >90° out-of-plane rotation for the Orc1 AAA+ domain disrupts interactions with catalytic amino acids in Orc4, narrowing and sealing off entry into the central channel. Prima facie, our data indicate that Drosophila ORC can switch between active and autoinhibited conformations, suggesting a novel means for cell cycle and/or developmental control of ORC functions. PMID:25762138

Towards elucidation of the mechanism of biological nanomotors

NASA Astrophysics Data System (ADS)

Zhao, Zhengyi

Biological functions such as cell mitosis, bacterial binary fission, DNA replication or repair, homologous recombination, Holliday junction resolution, viral genome packaging, and cell entry all involve biomotor-driven DNA translocation. In the past, the ubiquitous biological nanomotors were classified into two categories: linear and rotation motors. In 2013, we discovered a third type of biomotor, revolving motor without rotation. The revolving motion is further found to be widespread among many biological systems. In addition, the detailed sequential action mechanism of the ATPase ring in the phi29 dsDNA packaging motor has been elucidated: ATP binding induces a conformational entropy alternation of ATPase to a high affinity toward dsDNA; ATP hydrolysis triggers another conformational entropy change in ATPase to a low DNA affinity, by which the dsDNA substrate is pushed toward an adjacent ATPase subunit. The subunit communication is regulated by an arginine finger that extends from one ATPase subunit to the adjacent unit, resulting in an asymmetrical hexameric organization. Continuation of this process promotes the movement and revolving of the dsDNA within the hexameric ATPase ring. Coordination of all the motor components facilitate the motion direction control of the viral DNA packaging motors, and make it unusually powerful and effective. KEYWORDS: Phi29 dsDNA Packaging Motor, Bio-nanomotor, RNA Nanotechnology, DNA Translocase, One-Way Revolving, ASCE Superfamily, AAA+ Superfamily.

ATP Binding to p97/VCP D1 Domain Regulates Selective Recruitment of Adaptors to Its Proximal N-Domain

PubMed Central

Chia, Wei Sheng; Chia, Diana Xueqi; Rao, Feng; Bar Nun, Shoshana; Geifman Shochat, Susana

2012-01-01

p97/Valosin-containing protein (VCP) is a member of the AAA-ATPase family involved in many cellular processes including cell division, intracellular trafficking and extraction of misfolded proteins in endoplasmic reticulum-associated degradation (ERAD). It is a homohexamer with each subunit containing two tandem D1 and D2 ATPase domains and N- and C-terminal regions that function as adaptor protein binding domains. p97/VCP is directed to its many different functional pathways by associating with various adaptor proteins. The regulation of the recruitment of the adaptor proteins remains unclear. Two adaptor proteins, Ufd1/Npl4 and p47, which bind exclusively to the p97/VCP N-domain and direct p97/VCP to either ERAD-related processes or homotypic fusion of Golgi fragments, were studied here. Surface plasmon resonance biosensor-based assays allowed the study of binding kinetics in real time. In competition experiments, it was observed that in the presence of ATP, Ufd1/Npl4 was able to compete more effectively with p47 for binding to p97/VCP. By using non-hydrolysable ATP analogues and the hexameric truncated p97/N-D1 fragment, it was shown that binding rather than hydrolysis of ATP to the proximal D1 domain strengthened the Ufd1/Npl4 association with the N-domain, thus regulating the recruitment of either Ufd1/Npl4 or p47. This novel role of ATP and an assigned function to the D1 AAA-ATPase domain link the multiple functions of p97/VCP to the metabolic status of the cell. PMID:23226521

ATP binding to p97/VCP D1 domain regulates selective recruitment of adaptors to its proximal N-domain.

PubMed

Chia, Wei Sheng; Chia, Diana Xueqi; Rao, Feng; Bar Nun, Shoshana; Geifman Shochat, Susana

2012-01-01

p97/Valosin-containing protein (VCP) is a member of the AAA-ATPase family involved in many cellular processes including cell division, intracellular trafficking and extraction of misfolded proteins in endoplasmic reticulum-associated degradation (ERAD). It is a homohexamer with each subunit containing two tandem D1 and D2 ATPase domains and N- and C-terminal regions that function as adaptor protein binding domains. p97/VCP is directed to its many different functional pathways by associating with various adaptor proteins. The regulation of the recruitment of the adaptor proteins remains unclear. Two adaptor proteins, Ufd1/Npl4 and p47, which bind exclusively to the p97/VCP N-domain and direct p97/VCP to either ERAD-related processes or homotypic fusion of Golgi fragments, were studied here. Surface plasmon resonance biosensor-based assays allowed the study of binding kinetics in real time. In competition experiments, it was observed that in the presence of ATP, Ufd1/Npl4 was able to compete more effectively with p47 for binding to p97/VCP. By using non-hydrolysable ATP analogues and the hexameric truncated p97/N-D1 fragment, it was shown that binding rather than hydrolysis of ATP to the proximal D1 domain strengthened the Ufd1/Npl4 association with the N-domain, thus regulating the recruitment of either Ufd1/Npl4 or p47. This novel role of ATP and an assigned function to the D1 AAA-ATPase domain link the multiple functions of p97/VCP to the metabolic status of the cell.

Lis1 acts as a "clutch" between the ATPase and microtubule-binding domains of the dynein motor.

PubMed

Huang, Julie; Roberts, Anthony J; Leschziner, Andres E; Reck-Peterson, Samara L

2012-08-31

The lissencephaly protein Lis1 has been reported to regulate the mechanical behavior of cytoplasmic dynein, the primary minus-end-directed microtubule motor. However, the regulatory mechanism remains poorly understood. Here, we address this issue using purified proteins from Saccharomyces cerevisiae and a combination of techniques, including single-molecule imaging and single-particle electron microscopy. We show that rather than binding to the main ATPase site within dynein's AAA+ ring or its microtubule-binding stalk directly, Lis1 engages the interface between these elements. Lis1 causes individual dynein motors to remain attached to microtubules for extended periods, even during cycles of ATP hydrolysis that would canonically induce detachment. Thus, Lis1 operates like a "clutch" that prevents dynein's ATPase domain from transmitting a detachment signal to its track-binding domain. We discuss how these findings provide a conserved mechanism for dynein functions in living cells that require prolonged microtubule attachments. Copyright © 2012 Elsevier Inc. All rights reserved.

Lis1 Acts as a “Clutch” between the ATPase and Microtubule-Binding Domains of the Dynein Motor

PubMed Central

Huang, Julie; Roberts, Anthony J.; Leschziner, Andres E.; Reck-Peterson, Samara L.

2012-01-01

Summary The lissencephaly protein Lis1 has been reported to regulate the mechanical behavior of cytoplasmic dynein, the primary minus-end-directed microtubule motor. However, the regulatory mechanism remains poorly understood. Here, we address this issue using purified proteins from Saccharomyces cerevisiae and a combination of techniques, including single-molecule imaging and single-particle electron microscopy. We show that rather than binding to the main ATPase site within dynein's AAA+ ring or its microtubule-binding stalk directly, Lis1 engages the interface between these elements. Lis1 causes individual dynein motors to remain attached to microtubules for extended periods, even during cycles of ATP hydrolysis that would canonically induce detachment. Thus, Lis1 operates like a “clutch” that prevents dynein's ATPase domain from transmitting a detachment signal to its track-binding domain. We discuss how these findings provide a conserved mechanism for dynein functions in living cells that require prolonged microtubule attachments. PMID:22939623

Caenorhabditis elegans UBX cofactors for CDC-48/p97 control spermatogenesis.

PubMed

Sasagawa, Yohei; Yamanaka, Kunitoshi; Saito-Sasagawa, Yuko; Ogura, Teru

2010-12-01

UBX (ubiquitin regulatory X) domain-containing proteins act as cofactors for CDC-48/p97. CDC-48/p97 is essential for various cellular processes including retro-translocation in endoplasmic reticulum-associated degradation, homotypic membrane fusion, nuclear envelope assembly, degradation of ubiquitylated proteins, and cell cycle progression. CDC-48/p97-dependent processes are determined by differential binding of cofactors including UBX proteins, but the cellular functions of UBX proteins have not yet been elucidated, especially in multicellular organisms. Therefore, we investigated the functions of UBX family members using Caenorhabditis elegans, which expresses six UBX proteins, UBXN-1 to UBXN-6. All six UBXN proteins directly interacted with CDC-48.1 and CDC-48.2, and simultaneous knockdown of the expression of three genes, ubxn-1, ubxn-2 and ubxn-3, induced embryonic lethal and sterile phenotypes, but knockdown of either one or two did not. The sterile worms had a feminized germ-line phenotype, producing oocytes but no sperm. UBXN-1, UBXN-2 and UBXN-3 colocalized with CDC-48 in spermatocytes but not mature sperm. TRA-1A, which is a key factor in the sex determination pathway and inhibits spermatogenesis, accumulated in worms in which UBXN-1, UBXN-2 and UBXN-3 had been simultaneously knocked down. Taken together, these results suggest that UBXN-1, UBXN-2 and UBXN-3 are redundant cofactors for CDC-48/p97 and control spermatogenesis via the degradation of TRA-1A. © 2010 The Authors. Journal compilation © 2010 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd.

AAA+ Machines of Protein Destruction in Mycobacteria.

PubMed

Alhuwaider, Adnan Ali H; Dougan, David A

2017-01-01

The bacterial cytosol is a complex mixture of macromolecules (proteins, DNA, and RNA), which collectively are responsible for an enormous array of cellular tasks. Proteins are central to most, if not all, of these tasks and as such their maintenance (commonly referred to as protein homeostasis or proteostasis) is vital for cell survival during normal and stressful conditions. The two key aspects of protein homeostasis are, (i) the correct folding and assembly of proteins (coupled with their delivery to the correct cellular location) and (ii) the timely removal of unwanted or damaged proteins from the cell, which are performed by molecular chaperones and proteases, respectively. A major class of proteins that contribute to both of these tasks are the AAA+ (ATPases associated with a variety of cellular activities) protein superfamily. Although much is known about the structure of these machines and how they function in the model Gram-negative bacterium Escherichia coli , we are only just beginning to discover the molecular details of these machines and how they function in mycobacteria. Here we review the different AAA+ machines, that contribute to proteostasis in mycobacteria. Primarily we will focus on the recent advances in the structure and function of AAA+ proteases, the substrates they recognize and the cellular pathways they control. Finally, we will discuss the recent developments related to these machines as novel drug targets.

Peroxisomal monoubiquitinated PEX5 interacts with the AAA ATPases PEX1 and PEX6 and is unfolded during its dislocation into the cytosol.

PubMed

Pedrosa, Ana G; Francisco, Tânia; Bicho, Diana; Dias, Ana F; Barros-Barbosa, Aurora; Hagmann, Vera; Dodt, Gabriele; Rodrigues, Tony A; Azevedo, Jorge E

2018-06-08

PEX1 and PEX6 are two members of the ATPases Associated with diverse cellular Activities (AAA) family and the core components of the receptor export module (REM) of the peroxisomal matrix protein import machinery. Their role is to extract monoubiquitinated PEX5, the peroxisomal protein shuttling receptor, from the peroxisomal membrane docking/translocation module (DTM), so that a new cycle of protein transportation can start. Recent data have shown that PEX1 and PEX6 form a heterohexameric complex which unfolds substrates by processive threading. However, whether the natural substrate of the PEX1.PEX6 complex is monoubiquitinated PEX5 (Ub-PEX5) itself or some Ub-PEX5-interacting component(s) of the DTM remains unknown. In this work, we used an established cell-free in vitro system coupled with photoaffinity crosslinking and protein PEGylation assays to address this problem. We provide evidence suggesting that DTM-embedded Ub-PEX5 interacts directly with both PEX1 and PEX6 through its ubiquitin moiety and that the PEX5 polypeptide chain is globally unfolded during the ATP-dependent extraction event. These findings strongly suggest that DTM-embedded Ub-PEX5 is a bona fide substrate of the PEX1.PEX6 complex. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Structural insights into the Escherichia coli lysine decarboxylases and molecular determinants of interaction with the AAA+ ATPase RavA

PubMed Central

Kandiah, Eaazhisai; Carriel, Diego; Perard, Julien; Malet, Hélène; Bacia, Maria; Liu, Kaiyin; Chan, Sze W. S.; Houry, Walid A.; Ollagnier de Choudens, Sandrine; Elsen, Sylvie; Gutsche, Irina

2016-01-01

The inducible lysine decarboxylase LdcI is an important enterobacterial acid stress response enzyme whereas LdcC is its close paralogue thought to play mainly a metabolic role. A unique macromolecular cage formed by two decamers of the Escherichia coli LdcI and five hexamers of the AAA+ ATPase RavA was shown to counteract acid stress under starvation. Previously, we proposed a pseudoatomic model of the LdcI-RavA cage based on its cryo-electron microscopy map and crystal structures of an inactive LdcI decamer and a RavA monomer. We now present cryo-electron microscopy 3D reconstructions of the E. coli LdcI and LdcC, and an improved map of the LdcI bound to the LARA domain of RavA, at pH optimal for their enzymatic activity. Comparison with each other and with available structures uncovers differences between LdcI and LdcC explaining why only the acid stress response enzyme is capable of binding RavA. We identify interdomain movements associated with the pH-dependent enzyme activation and with the RavA binding. Multiple sequence alignment coupled to a phylogenetic analysis reveals that certain enterobacteria exert evolutionary pressure on the lysine decarboxylase towards the cage-like assembly with RavA, implying that this complex may have an important function under particular stress conditions. PMID:27080013

The Conserved ATPase Get3/Arr4 Modulates the Activity of Membrane-Associated Proteins in Saccharomyces cerevisiae

PubMed Central

Auld, Kathryn L.; Hitchcock, Amy L.; Doherty, Hugh K.; Frietze, Seth; Huang, Linda S.; Silver, Pamela A.

2006-01-01

The regulation of cellular membrane dynamics is crucial for maintaining proper cell growth and division. The Cdc48-Npl4-Ufd1 complex is required for several regulated membrane-associated processes as part of the ubiquitin–proteasome system, including ER-associated degradation and the control of lipid composition in yeast. In this study we report the results of a genetic screen in Saccharomyces cerevisiae for extragenic suppressors of a temperature-sensitive npl4 allele and the subsequent analysis of one suppressor, GET3/ARR4. The GET3 gene encodes an ATPase with homology to the regulatory component of the bacterial arsenic pump. Mutants of GET3 rescue several phenotypes of the npl4 mutant and transcription of GET3 is coregulated with the proteasome, illustrating a functional relationship between GET3 and NPL4 in the ubiquitin–proteasome system. We have further found that Get3 biochemically interacts with the trans-membrane domain proteins Get1/Mdm39 and Get2/Rmd7 and that Δget3 is able to suppress phenotypes of get1 and get2 mutants, including sporulation defects. In combination, our characterization of GET3 genetic and biochemical interactions with NPL4, GET1, and GET2 implicates Get3 in multiple membrane-dependent pathways. PMID:16816426

A Cdc48 “Retrochaperone” Function Is Required for the Solubility of Retrotranslocated, Integral Membrane Endoplasmic Reticulum-associated Degradation (ERAD-M) Substrates*

PubMed Central

Neal, Sonya; Mak, Raymond; Bennett, Eric J.; Hampton, Randolph

2017-01-01

A surprising feature of endoplasmic reticulum (ER)-associated degradation (ERAD) is the movement, or retrotranslocation, of ubiquitinated substrates from the ER lumen or membrane to the cytosol where they are degraded by the 26S proteasome. Multispanning ER membrane proteins, called ERAD-M substrates, are retrotranslocated to the cytosol as full-length intermediates during ERAD, and we have investigated how they maintain substrate solubility. Using an in vivo assay, we show that retrotranslocated ERAD-M substrates are moved to the cytoplasm as part of the normal ERAD pathway, where they are part of a solely proteinaceous complex. Using proteomics and direct biochemical confirmation, we found that Cdc48 serves as a critical “retrochaperone” for these ERAD-M substrates. Cdc48 binding to retrotranslocated, ubiquitinated ERAD-M substrates is required for their solubility; removal of the polyubiquitin chains or competition for binding by addition of free polyubiquitin liberated Cdc48 from retrotranslocated proteins and rendered them insoluble. All components of the canonical Cdc48 complex Cdc48-Npl4-Ufd1 were present in solubilized ERAD-M substrates. This function of the complex was observed for both HRD and DOA pathway substrates. Thus, in addition to the long known ATP-dependent extraction of ERAD substrates during retrotranslocation, the Cdc48 complex is generally and critically needed for the solubility of retrotranslocated ERAD-M intermediates. PMID:28077573

A Cdc48 "Retrochaperone" Function Is Required for the Solubility of Retrotranslocated, Integral Membrane Endoplasmic Reticulum-associated Degradation (ERAD-M) Substrates.

PubMed

Neal, Sonya; Mak, Raymond; Bennett, Eric J; Hampton, Randolph

2017-02-24

A surprising feature of endoplasmic reticulum (ER)-associated degradation (ERAD) is the movement, or retrotranslocation, of ubiquitinated substrates from the ER lumen or membrane to the cytosol where they are degraded by the 26S proteasome. Multispanning ER membrane proteins, called ERAD-M substrates, are retrotranslocated to the cytosol as full-length intermediates during ERAD, and we have investigated how they maintain substrate solubility. Using an in vivo assay, we show that retrotranslocated ERAD-M substrates are moved to the cytoplasm as part of the normal ERAD pathway, where they are part of a solely proteinaceous complex. Using proteomics and direct biochemical confirmation, we found that Cdc48 serves as a critical "retrochaperone" for these ERAD-M substrates. Cdc48 binding to retrotranslocated, ubiquitinated ERAD-M substrates is required for their solubility; removal of the polyubiquitin chains or competition for binding by addition of free polyubiquitin liberated Cdc48 from retrotranslocated proteins and rendered them insoluble. All components of the canonical Cdc48 complex Cdc48-Npl4-Ufd1 were present in solubilized ERAD-M substrates. This function of the complex was observed for both HRD and DOA pathway substrates. Thus, in addition to the long known ATP-dependent extraction of ERAD substrates during retrotranslocation, the Cdc48 complex is generally and critically needed for the solubility of retrotranslocated ERAD-M intermediates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

In Vivo Ubiquitin Linkage-type Analysis Reveals that the Cdc48-Rad23/Dsk2 Axis Contributes to K48-Linked Chain Specificity of the Proteasome.

PubMed

Tsuchiya, Hikaru; Ohtake, Fumiaki; Arai, Naoko; Kaiho, Ai; Yasuda, Sayaka; Tanaka, Keiji; Saeki, Yasushi

2017-05-18

Ubiquitin-binding domain (UBD) proteins regulate numerous cellular processes, but their specificities toward ubiquitin chain types in cells remain obscure. Here, we perform a quantitative proteomic analysis of ubiquitin linkage-type selectivity of 14 UBD proteins and the proteasome in yeast. We find that K48-linked chains are directed to proteasomal degradation through selectivity of the Cdc48 cofactor Npl4. Mutating Cdc48 results in decreased selectivity, and lacking Rad23/Dsk2 abolishes interactions between ubiquitylated substrates and the proteasome. Among them, only Npl4 has K48 chain specificity in vitro. Thus, the Cdc48 complex functions as a K48 linkage-specifying factor upstream of Rad23/Dsk2 for proteasomal degradation. On the other hand, K63 chains are utilized in endocytic pathways, whereas both K48 and K63 chains are found in the MVB and autophagic pathways. Collectively, our results provide an overall picture of the ubiquitin network via UBD proteins and identify the Cdc48-Rad23/Dsk2 axis as a major route to the proteasome. Copyright © 2017 Elsevier Inc. All rights reserved.

VCP/p97 cooperates with YOD1, UBXD1 and PLAA to drive clearance of ruptured lysosomes by autophagy.

PubMed

Papadopoulos, Chrisovalantis; Kirchner, Philipp; Bug, Monika; Grum, Daniel; Koerver, Lisa; Schulze, Nina; Poehler, Robert; Dressler, Alina; Fengler, Sven; Arhzaouy, Khalid; Lux, Vanda; Ehrmann, Michael; Weihl, Conrad C; Meyer, Hemmo

2017-01-17

Rupture of endosomes and lysosomes is a major cellular stress condition leading to cell death and degeneration. Here, we identified an essential role for the ubiquitin-directed AAA-ATPase, p97, in the clearance of damaged lysosomes by autophagy. Upon damage, p97 translocates to lysosomes and there cooperates with a distinct set of cofactors including UBXD1, PLAA, and the deubiquitinating enzyme YOD1, which we term ELDR components for Endo-Lysosomal Damage Response. Together, they act downstream of K63-linked ubiquitination and p62 recruitment, and selectively remove K48-linked ubiquitin conjugates from a subpopulation of damaged lysosomes to promote autophagosome formation. Lysosomal clearance is also compromised in MEFs harboring a p97 mutation that causes inclusion body myopathy and neurodegeneration, and damaged lysosomes accumulate in affected patient tissue carrying the mutation. Moreover, we show that p97 helps clear late endosomes/lysosomes ruptured by endocytosed tau fibrils. Thus, our data reveal an important mechanism of how p97 maintains lysosomal homeostasis, and implicate the pathway as a modulator of degenerative diseases. © 2016 The Authors.

The Role of the N-Domain in the ATPase Activity of the Mammalian AAA ATPase p97/VCP*

PubMed Central

Niwa, Hajime; Ewens, Caroline A.; Tsang, Chun; Yeung, Heidi O.; Zhang, Xiaodong; Freemont, Paul S.

2012-01-01

p97/valosin-containing protein (VCP) is a type II ATPase associated with various cellular activities that forms a homohexamer with each protomer containing an N-terminal domain (N-domain); two ATPase domains, D1 and D2; and a disordered C-terminal region. Little is known about the role of the N-domain or the C-terminal region in the p97 ATPase cycle. In the p97-associated human disease inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia, the majority of missense mutations are located at the N-domain D1 interface. Structure-based predictions suggest that such mutations affect the interaction of the N-domain with D1. Here we have tested ten major inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia-linked mutants for ATPase activity and found that all have increased activity over the wild type, with one mutant, p97A232E, having three times higher activity. Further mutagenesis of p97A232E shows that the increase in ATPase activity is mediated through D2 and requires both the N-domain and a flexible ND1 linker. A disulfide mutation that locks the N-domain to D1 in a coplanar position reversibly abrogates ATPase activity. A cryo-EM reconstruction of p97A232E suggests that the N-domains are flexible. Removal of the C-terminal region also reduces ATPase activity. Taken together, our data suggest that the conformation of the N-domain in relation to the D1-D2 hexamer is directly linked to ATP hydrolysis and that the C-terminal region is required for hexamer stability. This leads us to propose a model where the N-domain adopts either of two conformations: a flexible conformation compatible with ATP hydrolysis or a coplanar conformation that is inactive. PMID:22270372

Structure and regulatory role of the C-terminal winged helix domain of the archaeal minichromosome maintenance complex

PubMed Central

Wiedemann, Christoph; Szambowska, Anna; Häfner, Sabine; Ohlenschläger, Oliver; Gührs, Karl-Heinz; Görlach, Matthias

2015-01-01

The minichromosome maintenance complex (MCM) represents the replicative DNA helicase both in eukaryotes and archaea. Here, we describe the solution structure of the C-terminal domains of the archaeal MCMs of Sulfolobus solfataricus (Sso) and Methanothermobacter thermautotrophicus (Mth). Those domains consist of a structurally conserved truncated winged helix (WH) domain lacking the two typical ‘wings’ of canonical WH domains. A less conserved N-terminal extension links this WH module to the MCM AAA+ domain forming the ATPase center. In the Sso MCM this linker contains a short α-helical element. Using Sso MCM mutants, including chimeric constructs containing Mth C-terminal domain elements, we show that the ATPase and helicase activity of the Sso MCM is significantly modulated by the short α-helical linker element and by N-terminal residues of the first α-helix of the truncated WH module. Finally, based on our structural and functional data, we present a docking-derived model of the Sso MCM, which implies an allosteric control of the ATPase center by the C-terminal domain. PMID:25712103

LRRK2 phosphorylates pre-synaptic N-ethylmaleimide sensitive fusion (NSF) protein enhancing its ATPase activity and SNARE complex disassembling rate.

PubMed

Belluzzi, Elisa; Gonnelli, Adriano; Cirnaru, Maria-Daniela; Marte, Antonella; Plotegher, Nicoletta; Russo, Isabella; Civiero, Laura; Cogo, Susanna; Carrion, Maria Perèz; Franchin, Cinzia; Arrigoni, Giorgio; Beltramini, Mariano; Bubacco, Luigi; Onofri, Franco; Piccoli, Giovanni; Greggio, Elisa

2016-01-13

Lrrk2, a gene linked to Parkinson's disease, encodes a large scaffolding protein with kinase and GTPase activities implicated in vesicle and cytoskeletal-related processes. At the presynaptic site, LRRK2 associates with synaptic vesicles through interaction with a panel of presynaptic proteins. Here, we show that LRRK2 kinase activity influences the dynamics of synaptic vesicle fusion. We therefore investigated whether LRRK2 phosphorylates component(s) of the exo/endocytosis machinery. We have previously observed that LRRK2 interacts with NSF, a hexameric AAA+ ATPase that couples ATP hydrolysis to the disassembling of SNARE proteins allowing them to enter another fusion cycle during synaptic exocytosis. Here, we demonstrate that NSF is a substrate of LRRK2 kinase activity. LRRK2 phosphorylates full-length NSF at threonine 645 in the ATP binding pocket of D2 domain. Functionally, NSF phosphorylated by LRRK2 displays enhanced ATPase activity and increased rate of SNARE complex disassembling. Substitution of threonine 645 with alanine abrogates LRRK2-mediated increased ATPase activity. Given that the most common Parkinson's disease LRRK2 G2019S mutation displays increased kinase activity, our results suggest that mutant LRRK2 may impair synaptic vesicle dynamics via aberrant phosphorylation of NSF.

STAND, a class of P-loop NTPases including animal and plant regulators of programmed cell death: multiple, complex domain architectures, unusual phyletic patterns, and evolution by horizontal gene transfer.

PubMed

Leipe, Detlef D; Koonin, Eugene V; Aravind, L

2004-10-08

Using sequence profile analysis and sequence-based structure predictions, we define a previously unrecognized, widespread class of P-loop NTPases. The signal transduction ATPases with numerous domains (STAND) class includes the AP-ATPases (animal apoptosis regulators CED4/Apaf-1, plant disease resistance proteins, and bacterial AfsR-like transcription regulators) and NACHT NTPases (e.g. NAIP, TLP1, Het-E-1) that have been studied extensively in the context of apoptosis, pathogen response in animals and plants, and transcriptional regulation in bacteria. We show that, in addition to these well-characterized protein families, the STAND class includes several other groups of (predicted) NTPase domains from diverse signaling and transcription regulatory proteins from bacteria and eukaryotes, and three Archaea-specific families. We identified the STAND domain in several biologically well-characterized proteins that have not been suspected to have NTPase activity, including soluble adenylyl cyclases, nephrocystin 3 (implicated in polycystic kidney disease), and Rolling pebble (a regulator of muscle development); these findings are expected to facilitate elucidation of the functions of these proteins. The STAND class belongs to the additional strand, catalytic E division of P-loop NTPases together with the AAA+ ATPases, RecA/helicase-related ATPases, ABC-ATPases, and VirD4/PilT-like ATPases. The STAND proteins are distinguished from other P-loop NTPases by the presence of unique sequence motifs associated with the N-terminal helix and the core strand-4, as well as a C-terminal helical bundle that is fused to the NTPase domain. This helical module contains a signature GxP motif in the loop between the two distal helices. With the exception of the archaeal families, almost all STAND NTPases are multidomain proteins containing three or more domains. In addition to the NTPase domain, these proteins typically contain DNA-binding or protein-binding domains, superstructure-forming repeats, such as WD40 and TPR, and enzymatic domains involved in signal transduction, including adenylate cyclases and kinases. By analogy to the AAA+ ATPases, it can be predicted that STAND NTPases use the C-terminal helical bundle as a "lever" to transmit the conformational changes brought about by NTP hydrolysis to effector domains. STAND NTPases represent a novel paradigm in signal transduction, whereby adaptor, regulatory switch, scaffolding, and, in some cases, signal-generating moieties are combined into a single polypeptide. The STAND class consists of 14 distinct families, and the evolutionary history of most of these families is riddled with dramatic instances of lineage-specific expansion and apparent horizontal gene transfer. The STAND NTPases are most abundant in developmentally and organizationally complex prokaryotes and eukaryotes. Transfer of genes for STAND NTPases from bacteria to eukaryotes on several occasions might have played a significant role in the evolution of eukaryotic signaling systems.

GRP75 upregulates clathrin-independent endocytosis through actin cytoskeleton reorganization mediated by the concurrent activation of Cdc42 and RhoA.

PubMed

Chen, Hang; Gao, Zhihui; He, Changzheng; Xiang, Rong; van Kuppevelt, Toin H; Belting, Mattias; Zhang, Sihe

2016-05-01

Therapeutic macromolecules are internalized into the cell by either clathrin-mediated endocytosis (CME) or clathrin-independent endocytosis (CIE). Although some chaperone proteins play an essential role in CME (e.g. Hsc70 in clathrin uncoating), relatively few of these proteins are functionally involved in CIE. We previously revealed a role for the mitochondrial chaperone protein GRP75 in heparan sulfate proteoglycan (HSPG)-mediated, membrane raft-associated macromolecule endocytosis. However, the mechanism underlying this process remains unclear. In this study, using a mitochondrial signal peptide-directed protein trafficking expression strategy, we demonstrate that wild-type GRP75 expression enhanced the uptakes of HSPG and CIE marker cholera toxin B subunit but impaired the uptake of CME marker transferrin. The endocytosis regulation function of GRP75 is largely mediated by its subcellular location in mitochondria and is essentially determined by its ATPase domain. Interestingly, the mitochondrial expression of GRP75 or its ATPase domain significantly stimulates increases in both RhoA and Cdc42 activation, remarkably induces stress fibers and enhances filopodia formation, which collectively results in the promotion of CIE, but the inhibition of CME. Furthermore, silencing of Cdc42 or RhoA impaired the ability of GRP75 overexpression to increase CIE. Therefore, these results suggest that endocytosis vesicle enrichment of GRP75 by mitochondria trafficking upregulates CIE through an actin cytoskeleton reorganization mechanism mediated by the concurrent activation of Cdc42 and RhoA. This finding provides novel insight into organelle-derived chaperone signaling and the regulation of different endocytosis pathways in cells. Copyright © 2016 Elsevier Inc. All rights reserved.

The RavA-ViaA Chaperone-Like System Interacts with and Modulates the Activity of the Fumarate Reductase Respiratory Complex.

PubMed

Wong, Keith S; Bhandari, Vaibhav; Janga, Sarath Chandra; Houry, Walid A

2017-01-20

Regulatory ATPase variant A (RavA) is a MoxR AAA+ protein that functions together with a partner protein that we termed VWA interacting with AAA+ ATPase (ViaA) containing a von Willebrand Factor A domain. However, the functional role of RavA-ViaA in the cell is not yet well established. Here, we show that RavA-ViaA are functionally associated with anaerobic respiration in Escherichia coli through interactions with the fumarate reductase (Frd) electron transport complex. Expression analysis of ravA and viaA genes showed that both proteins are co-expressed with multiple anaerobic respiratory genes, many of which are regulated by the anaerobic transcriptional regulator Fnr. Consistently, the expression of both ravA and viaA was found to be dependent on Fnr in cells grown under oxygen-limiting condition. ViaA was found to physically interact with FrdA, the flavin-containing subunit of the Frd complex. Both RavA and the Fe-S-containing subunit of the Frd complex, FrdB, regulate this interaction. Importantly, Frd activity was observed to increase in the absence of RavA and ViaA. This indicates that RavA and ViaA modulate the activity of the Frd complex, signifying a potential regulatory chaperone-like function for RavA-ViaA during bacterial anaerobic respiration with fumarate as the terminal electron acceptor. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Rice AAA-ATPase OsFIGNL1 Is Essential for Male Meiosis

PubMed Central

Zhang, Peipei; Zhang, Yingxin; Sun, Lianping; Sinumporn, Sittipun; Yang, Zhengfu; Sun, Bin; Xuan, Dandan; Li, Zihe; Yu, Ping; Wu, Weixun; Wang, Kejian; Cao, Liyong; Cheng, Shihua

2017-01-01

Meiosis is crucial in reproduction of plants and ensuring genetic diversity. Although several genes involved in homologous recombination and DNA repair have been reported, their functions in rice (Oryza sativa) male meiosis remain poorly understood. Here, we isolated and characterized the rice OsFIGNL1 (OsFidgetin-like 1) gene, encoding a conserved AAA-ATPase, and explored its function and importance in male meiosis and pollen formation. The rice Osfignl1 mutant exhibited normal vegetative growth, but failed to produce seeds and displayed pollen abortion phenotype. Phenotypic comparisons between the wild-type and Osfignl1 mutant demonstrated that OsFIGNL1 is required for anther development, and that the recessive mutation of this gene causes male sterility in rice. Complementation and CRISPR/Cas9 experiments demonstrated that wild-type OsFIGNL1 is responsible for the male sterility phenotype. Subcellular localization showed that OsFIGNL1-green fluorescent protein was exclusively localized in the nucleus of rice protoplasts. Male meiosis in the Osfignl1 mutant exhibited abnormal chromosome behavior, including chromosome bridges and multivalent chromosomes at diakinesis, lagging chromosomes, and chromosome fragments during meiosis. Yeast two-hybrid assays demonstrated OsFIGNL1 could interact with RAD51A1, RAD51A2, DMC1A, DMC1B, and these physical interactions were further confirmed by BiFC assay. Taken together, our results suggest that OsFIGNL1 plays an important role in regulation of male meiosis and anther development. PMID:29021797

Functional Characterization of Ice Plant SKD1, an AAA-Type ATPase Associated with the Endoplasmic Reticulum-Golgi Network, and Its Role in Adaptation to Salt Stress1[W

PubMed Central

Jou, Yingtzy; Chiang, Chih-Pin; Jauh, Guang-Yuh; Yen, Hungchen Emilie

2006-01-01

A salt-induced gene mcSKD1 (suppressor of K+ transport growth defect) able to facilitate K+ uptake has previously been identified from the halophyte ice plant (Mesembryanthemum crystallinum). The sequence of mcSKD1 is homologous to vacuolar protein sorting 4, an ATPase associated with a variety of cellular activities-type ATPase that participates in the sorting of vacuolar proteins into multivesicular bodies in yeast (Saccharomyces cerevisiae). Recombinant mcSKD1 exhibited ATP hydrolytic activities in vitro with a half-maximal rate at an ATP concentration of 1.25 mm. Point mutations on active site residues abolished its ATPase activity. ADP is both a product and a strong inhibitor of the reaction. ADP-binding form of mcSDK1 greatly reduced its catalytic activity. The mcSKD1 protein accumulated ubiquitously in both vegetative and reproductive parts of plants. Highest accumulation was observed in cells actively engaging in the secretory processes, such as bladder cells of leaf epidermis. Membrane fractionation and double-labeling immunofluorescence showed the predominant localization of mcSKD1 in the endoplasmic reticulum-Golgi network. Immunoelectron microscopy identified the formation of mcSKD1 proteins into small aggregates in the cytosol and associated with membrane continuum within the endomembrane compartments. These results indicated that this ATPase participates in the endoplasmic reticulum-Golgi mediated protein sorting machinery for both housekeeping function and compartmentalization of excess Na+ under high salinity. PMID:16581876

Aortic stent grafting: a new approach to a deadly diagnosis: one hospital's findings in defining new care processes.

PubMed

Kalinowski, H

2001-01-01

Ruptured abdominal aortic aneurysm (AAA) is the 13th leading cause of death in the United States. Diagnosis is the key to prevention of death from AAA. Millions of Americans harbor this silent, potentially lethal aneurysm. For over 50 years, conventional open surgical repair has been performed for ruptured aortic abdominal aneurysm. It is a major operation with an extended hospital stay and recovery period. An alternative approach to AAA repair has evolved over the past 10 years that combines advances in catheter and stent technologies. With the AAA aortic stent graft, patients usually do not require intensive care and are discharged home within 48 hours of the procedure. This article describes the AAA aortic stent graft procedure, in the formation of a case management team to develop a clinical pathway and standing orders for these patients and defines the outcomes of care.

Two C-C Family Chemokines, Eotaxin and RANTES, Are Novel Independent Plasma Biomarkers for Abdominal Aortic Aneurysm.

PubMed

Jones, Gregory T; Phillips, L Victoria; Williams, Michael J A; van Rij, Andre M; Kabir, Tasnuva D

2016-04-28

Inflammation of the aortic wall is recognised as a key pathogenesis of abdominal aortic aneurysm (AAA). This study was undertaken to determine whether inflammatory cytokines could be used as biomarkers for the presence of AAA. Tissue profiles of 27 inflammatory cytokine were examined in AAA (n=14) and nonaneurysmal (n=14) aortic tissues. Three cytokines, regulated upon activation normally T-cell expressed and secreted (RANTES), eotaxin, and macrophage inflammatory protein 1 beta (MIP-1b), had increased expression in AAA, particularly within the adventitial layer of the aortic wall. Basic fibroblast growth factor (bFGF) had reduced expression in all layers of the AAA wall. Examination of the circulating plasma profiles of AAA (n=442) and AAA-free controls (n=970) suggested a (risk factor adjusted) AAA-association with eotaxin, RANTES, and high sensitivity C-reactive protein (hsCRP). A plasma inflammatory cytokine score, calculated using these three markers, suggested a strong risk association with AAA (odds ratio, 4.8; 95% CI, 3.5-6.7; P<0.0001), independent of age, sex, history of ischemic heart disease, and smoking. Contrary to reports suggesting a distinct T helper 2-associated inflammatory profile in AAA, this current study suggests a more-generalized pattern of inflammation, albeit with some potentially distinct features, including elevated plasma eotaxin and decreased plasma RANTES. In combination with hsCRP, these markers may have potential utility as AAA biomarkers. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

DNA replication initiator Cdc6 also regulates ribosomal DNA transcription initiation.

PubMed

Huang, Shijiao; Xu, Xiaowei; Wang, Guopeng; Lu, Guoliang; Xie, Wenbing; Tao, Wei; Zhang, Hongyin; Jiang, Qing; Zhang, Chuanmao

2016-04-01

RNA-polymerase-I-dependent ribosomal DNA (rDNA) transcription is fundamental to rRNA processing, ribosome assembly and protein synthesis. However, how this process is initiated during the cell cycle is not fully understood. By performing a proteomic analysis of transcription factors that bind RNA polymerase I during rDNA transcription initiation, we identified that the DNA replication initiator Cdc6 interacts with RNA polymerase I and its co-factors, and promotes rDNA transcription in G1 phase in an ATPase-activity-dependent manner. We further showed that Cdc6 is targeted to the nucleolus during late mitosis and G1 phase in a manner that is dependent on B23 (also known as nucleophosmin, NPM1), and preferentially binds to the rDNA promoter through its ATP-binding domain. Overexpression of Cdc6 increases rDNA transcription, whereas knockdown of Cdc6 results in a decreased association of both RNA polymerase I and the RNA polymerase I transcription factor RRN3 with rDNA, and a reduction of rDNA transcription. Furthermore, depletion of Cdc6 impairs the interaction between RRN3 and RNA polymerase I. Taken together, our data demonstrate that Cdc6 also serves as a regulator of rDNA transcription initiation, and indicate a mechanism by which initiation of rDNA transcription and DNA replication can be coordinated in cells. © 2016. Published by The Company of Biologists Ltd.

Integrated regulation of PIKK-mediated stress responses by AAA+ proteins RUVBL1 and RUVBL2

PubMed Central

Izumi, Natsuko; Yamashita, Akio; Ohno, Shigeo

2012-01-01

Proteins of the phosphatidylinositol 3-kinase-related protein kinase (PIKK) family are activated by various cellular stresses, including DNA damage, premature termination codon and nutritional status, and induce appropriate cellular responses. The importance of PIKK functions in the maintenance of genome integrity, accurate gene expression and the proper control of cell growth/proliferation is established. Recently, ATPase associated diverse cellular activities (AAA+) proteins RUVBL1 and RUVBL2 (RUVBL1/2) have been shown to be common regulators of PIKKs. The RUVBL1/2 complex regulates PIKK-mediated stress responses through physical interactions with PIKKs and by controlling PIKK mRNA levels. In this review, the functions of PIKKs in stress responses are outlined and the physiological significance of the integrated regulation of PIKKs by the RUVBL1/2 complex is presented. We also discuss a putative “PIKK regulatory chaperone complex” including other PIKK regulators, Hsp90 and the Tel2 complex. PMID:22540023

The AAA-ATPase NVL2 is a component of pre-ribosomal particles that interacts with the DExD/H-box RNA helicase DOB1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagahama, Masami; Yamazoe, Takeshi; Hara, Yoshimitsu

2006-08-04

Nuclear VCP/p97-like protein 2 (NVL2) is a member of the chaperone-like AAA-ATPase family with two conserved ATP-binding modules. Our previous studies have shown that NVL2 is localized to the nucleolus by interacting with ribosomal protein L5 and may participate in ribosome synthesis, a process involving various non-ribosomal factors including chaperones and RNA helicases. Here, we show that NVL2 is associated with pre-ribosomal particles in the nucleus. Moreover, we used yeast two-hybrid and co-immunoprecipitation assays to identify an NVL2-interacting protein that could yield insights into NVL2 function in ribosome biogenesis. We found that NVL2 interacts with DOB1, a DExD/H-box RNA helicase,more » whose yeast homologue functions in a late stage of the 60S subunit synthesis. DOB1 can interact with a second ATP-binding module mutant of NVL2, which shows a dominant negative effect on ribosome synthesis. In contrast, it cannot interact with a first ATP-binding module mutant, which does not show the dominant negative effect. When the dominant negative mutant of NVL2 was overexpressed in cells, DOB1 appeared to remain associated with nuclear pre-ribosomal particles. Such accumulation was not observed upon overexpression of wild-type NVL2 or a nondominant-negative mutant. Taken together, our results suggest that NVL2 might regulate the association/dissociation reaction of DOB1 with pre-ribosomal particles by acting as a molecular chaperone.« less

A Fragment-Based Ligand Screen Against Part of a Large Protein Machine: The ND1 Domains of the AAA+ ATPase p97/VCP.

PubMed

Chimenti, Michael S; Bulfer, Stacie L; Neitz, R Jeffrey; Renslo, Adam R; Jacobson, Matthew P; James, Thomas L; Arkin, Michelle R; Kelly, Mark J S

2015-07-01

The ubiquitous AAA+ ATPase p97 functions as a dynamic molecular machine driving several cellular processes. It is essential in regulating protein homeostasis, and it represents a potential drug target for cancer, particularly when there is a greater reliance on the endoplasmic reticulum-associated protein degradation pathway and ubiquitin-proteasome pathway to degrade an overabundance of secreted proteins. Here, we report a case study for using fragment-based ligand design approaches against this large and dynamic hexamer, which has multiple potential binding sites for small molecules. A screen of a fragment library was conducted by surface plasmon resonance (SPR) and followed up by nuclear magnetic resonance (NMR), two complementary biophysical techniques. Virtual screening was also carried out to examine possible binding sites for the experimental hits and evaluate the potential utility of fragment docking for this target. Out of this effort, 13 fragments were discovered that showed reversible binding with affinities between 140 µM and 1 mM, binding stoichiometries of 1:1 or 2:1, and good ligand efficiencies. Structural data for fragment-protein interactions were obtained with residue-specific [U-(2)H] (13)CH3-methyl-labeling NMR strategies, and these data were compared to poses from docking. The combination of virtual screening, SPR, and NMR enabled us to find and validate a number of interesting fragment hits and allowed us to gain an understanding of the structural nature of fragment binding. © 2015 Society for Laboratory Automation and Screening.

Cytolethal distending toxins require components of the ER-associated degradation pathway for host cell entry.

PubMed

Eshraghi, Aria; Dixon, Shandee D; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C; Damoiseaux, Robert; Blanke, Steven R; Bradley, Kenneth A

2014-07-01

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins.

Cytolethal Distending Toxins Require Components of the ER-Associated Degradation Pathway for Host Cell Entry

PubMed Central

Eshraghi, Aria; Dixon, Shandee D.; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C.; Damoiseaux, Robert; Blanke, Steven R.; Bradley, Kenneth A.

2014-01-01

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins. PMID:25078082

Phosphatidylserine Stimulation of Drs2p·Cdc50p Lipid Translocase Dephosphorylation Is Controlled by Phosphatidylinositol-4-phosphate*

PubMed Central

Jacquot, Aurore; Montigny, Cédric; Hennrich, Hanka; Barry, Raphaëlle; le Maire, Marc; Jaxel, Christine; Holthuis, Joost; Champeil, Philippe; Lenoir, Guillaume

2012-01-01

Here, Drs2p, a yeast lipid translocase that belongs to the family of P4-type ATPases, was overexpressed in the yeast Saccharomyces cerevisiae together with Cdc50p, its glycosylated partner, as a result of the design of a novel co-expression vector. The resulting high yield allowed us, using crude membranes or detergent-solubilized membranes, to measure the formation from [γ-32P]ATP of a 32P-labeled transient phosphoenzyme at the catalytic site of Drs2p. Formation of this phosphoenzyme could be detected only if Cdc50p was co-expressed with Drs2p but was not dependent on full glycosylation of Cdc50p. It was inhibited by orthovanadate and fluoride compounds. In crude membranes, the phosphoenzyme formed at steady state at 4 °C displayed ADP-insensitive but temperature-sensitive decay. Solubilizing concentrations of dodecyl maltoside left this decay rate almost unaltered, whereas several other detergents accelerated it. Unexpectedly, the dephosphorylation rate for the solubilized Drs2p·Cdc50p complex was inhibited by the addition of phosphatidylserine. Phosphatidylserine exerted its anticipated accelerating effect on the dephosphorylation of Drs2p·Cdc50p complex only in the additional presence of phosphatidylinositol-4-phosphate. These results explain why phosphatidylinositol-4-phosphate tightly controls Drs2p-catalyzed lipid transport and establish the functional relevance of the Drs2p·Cdc50p complex overexpressed here. PMID:22351780

The prevalence of abdominal aortic aneurysms in the rural/urban population in central Poland - Gniewkowo Aortic Study.

PubMed

Dereziński, Tadeusz L; Fórmankiewicz, Bartosz; Migdalski, Arkadiusz; Brazis, Paweł; Jakubowski, Grzegorz; Woda, Łukasz; Jawień, Arkadiusz

2017-01-01

Abdominal aortic aneurysm (AAA) is a widening of the aorta below the renal arteries with a diameter equal to or greater than 3 cm. The prevalence of AAA is estimated at 4-8% in men aged 65 years or older and 1-2% among women over 65 years old. Participation in screening programmes has decreased the number of aortic ruptures. All men aged 60 years and older, and women aged 65 years and older living in the rural/urban commune in central Poland were invited to participate in the study. In total 922 persons (61% of the invited population) entered the study. The men were divided into two groups: 60-64 years old, and 65 years and older. Screening abdomen ultrasound was performed and demographic data was collected. Among the 922 examined persons two (1.01%) AAAs were diagnosed in the group of men 60-64 years of age, three (0.82%) AAAs amongst women ≥ 65 years old, and 33 (9.29%) AAAs were found in the group of men aged 65 years and older. A positive relationship between the presence of AAA and smoking (p = 0.0048), age of men (p = 0.0009), and history of myocardial infarction/acute coronary syndrome (MI/ACS) (p = 0.0079) was found. There was no correlation between the frequency of AAA and diabetes mellitus (p = 0.46), hypertension (p = 0.38), and family history of AAA (p = 0.44). The prevalence of AAA in men aged 65 years and older is seemingly larger than in previously conducted studies, while among men 60-64 years of age and women aged ≥ 65 it is similar. Older age, smoking, and a history of MI/ACS were the most important risk factors of AAA occurrence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demircioglu, F. Esra; Sosa, Brian A.; Ingram, Jessica

The most common cause of early onset primary dystonia, a neuromuscular disease, is a glutamate deletion (ΔE) at position 302/303 of TorsinA, a AAA+ ATPase that resides in the endoplasmic reticulum. While the function of TorsinA remains elusive, the ΔE mutation is known to diminish binding of two TorsinA ATPase activators: lamina-associated protein 1 (LAP1) and its paralog, luminal domain like LAP1 (LULL1). Using a nanobody as a crystallization chaperone, we obtained a 1.4 Å crystal structure of human TorsinA in complex with LULL1. This nanobody likewise stabilized the weakened TorsinAΔE-LULL1 interaction, which enabled us to solve its structure atmore » 1.4 Å also. A comparison of these structures shows, in atomic detail, the subtle differences in activator interactions that separate the healthy from the diseased state. This information may provide a structural platform for drug development, as a small molecule that rescues TorsinAΔE could serve as a cure for primary dystonia.« less

Asymmetric ring structure of Vps4 required for ESCRT-III disassembly

NASA Astrophysics Data System (ADS)

Caillat, Christophe; Macheboeuf, Pauline; Wu, Yuanfei; McCarthy, Andrew A.; Boeri-Erba, Elisabetta; Effantin, Gregory; Göttlinger, Heinrich G.; Weissenhorn, Winfried; Renesto, Patricia

2015-12-01

The vacuolar protein sorting 4 AAA-ATPase (Vps4) recycles endosomal sorting complexes required for transport (ESCRT-III) polymers from cellular membranes. Here we present a 3.6-Å X-ray structure of ring-shaped Vps4 from Metallosphera sedula (MsVps4), seen as an asymmetric pseudohexamer. Conserved key interface residues are shown to be important for MsVps4 assembly, ATPase activity in vitro, ESCRT-III disassembly in vitro and HIV-1 budding. ADP binding leads to conformational changes within the protomer, which might propagate within the ring structure. All ATP-binding sites are accessible and the pseudohexamer binds six ATP with micromolar affinity in vitro. In contrast, ADP occupies one high-affinity and five low-affinity binding sites in vitro, consistent with conformational asymmetry induced on ATP hydrolysis. The structure represents a snapshot of an assembled Vps4 conformation and provides insight into the molecular motions the ring structure undergoes in a concerted action to couple ATP hydrolysis to ESCRT-III substrate disassembly.

Analysis of the crystal structure of an active MCM hexamer.

PubMed

Miller, Justin M; Arachea, Buenafe T; Epling, Leslie B; Enemark, Eric J

2014-09-29

In a previous Research article (Froelich et al., 2014), we suggested an MCM helicase activation mechanism, but were limited in discussing the ATPase domain because it was absent from the crystal structure. Here we present the crystal structure of a nearly full-length MCM hexamer that is helicase-active and thus has all features essential for unwinding DNA. The structure is a chimera of Sulfolobus solfataricus N-terminal domain and Pyrococcus furiosus ATPase domain. We discuss three major findings: 1) a novel conformation for the A-subdomain that could play a role in MCM regulation; 2) interaction of a universally conserved glutamine in the N-terminal Allosteric Communication Loop with the AAA+ domain helix-2-insert (h2i); and 3) a recessed binding pocket for the MCM ssDNA-binding motif influenced by the h2i. We suggest that during helicase activation, the h2i clamps down on the leading strand to facilitate strand retention and regulate ATP hydrolysis.

GENERAL CONTROL NONREPRESSIBLE4 Degrades 14-3-3 and the RIN4 Complex to Regulate Stomatal Aperture with Implications on Nonhost Disease Resistance and Drought Tolerance[OPEN

PubMed Central

Oh, Sunhee; Lee, Hee-Kyung; Rojas, Clemencia M.

2017-01-01

Plants have complex and adaptive innate immune responses against pathogen infections. Stomata are key entry points for many plant pathogens. Both pathogens and plants regulate stomatal aperture for pathogen entry and defense, respectively. Not all plant proteins involved in stomatal aperture regulation have been identified. Here, we report GENERAL CONTROL NONREPRESSIBLE4 (GCN4), an AAA+-ATPase family protein, as one of the key proteins regulating stomatal aperture during biotic and abiotic stress. Silencing of GCN4 in Nicotiana benthamiana and Arabidopsis thaliana compromises host and nonhost disease resistance due to open stomata during pathogen infection. AtGCN4 overexpression plants have reduced H+-ATPase activity, stomata that are less responsive to pathogen virulence factors such as coronatine (phytotoxin produced by the bacterium Pseudomonas syringae) or fusicoccin (a fungal toxin produced by the fungus Fusicoccum amygdali), reduced pathogen entry, and enhanced drought tolerance. This study also demonstrates that AtGCN4 interacts with RIN4 and 14-3-3 proteins and suggests that GCN4 degrades RIN4 and 14-3-3 proteins via a proteasome-mediated pathway and thereby reduces the activity of the plasma membrane H+-ATPase complex, thus reducing proton pump activity to close stomata. PMID:28855332

Prevalence of previously undiagnosed abdominal aortic aneurysms in the area of Como: the ComoCuore "looking for AAA" ultrasonography screening.

PubMed

Corrado, Giovanni; Durante, Alessandro; Genchi, Vincenzo; Trabattoni, Loris; Beretta, Sandro; Rovelli, Enza; Foglia-Manzillo, Giovanni; Ferrari, Giovanni

2016-08-01

The prognosis for abdominal aortic aneurysm (AAA) rupture is poor. Long-term follow-up of population-based randomized trials has demonstrated that ultrasound (US) screening for abdominal aortic aneurysms (AAAs) measuring 3 cm or greater decreases AAA-related mortality rates and is cost-effective. We though to prospectively perform during a 26-month period a limited US examination of the infrarenal aorta in volunteers of both gender aged 60-85 years without history of AAA living in the area of Como, Italy. From September 2010 to November 2013 ComoCuore, a no-profit nongovernmental association, enrolled 1555 people (aged 68.8 ± 6.8 years; 48.6 % males). Clinical data and a US imaging of the aorta were collected for each participant. AAA was found in 22 volunteers (1.4 %) mainly males (2.5 % in males vs. 0.4 % in females p = 0.005). Overall, the prevalence of cardiovascular risk factors was higher in patients with vs. without AAA (mean 2.9 ± 3.0 vs. 1.4 ± 1.0 respectively, p < 0.0001). Independent predictors of AAA on multivariate analysis were age (OR 1.14, 1.06-1.22; p < 0.0001), male gender (OR 8.23, 1.79-37.91; p = 0.007), and both current (OR 4.98, 1.57-15.79; p = 0.007) and previous smoking (OR 2.76, 1.12-8.94; p = 0.03). Our study confirms the feasibility of one time US screening for AAA in a large cohort of asymptomatic people. Independent predictors of AAA were male sex, older age and a history of smoking. Accordingly to recent data the prevalence of AAA seems to be declining, maybe due to a reduction of smoking in Italy.

The BiP Molecular Chaperone Plays Multiple Roles during the Biogenesis of TorsinA, an AAA+ ATPase Associated with the Neurological Disease Early-onset Torsion Dystonia*

PubMed Central

Zacchi, Lucía F.; Wu, Hui-Chuan; Bell, Samantha L.; Millen, Linda; Paton, Adrienne W.; Paton, James C.; Thomas, Philip J.; Zolkiewski, Michal; Brodsky, Jeffrey L.

2014-01-01

Early-onset torsion dystonia (EOTD) is a neurological disorder characterized by involuntary and sustained muscle contractions that can lead to paralysis and abnormal posture. EOTD is associated with the deletion of a glutamate (ΔE) in torsinA, an endoplasmic reticulum (ER) resident AAA+ ATPase. To date, the effect of ΔE on torsinA and the reason that this mutation results in EOTD are unclear. Moreover, there are no specific therapeutic options to treat EOTD. To define the underlying biochemical defects associated with torsinAΔE and to uncover factors that might be targeted to offset defects associated with torsinAΔE, we developed a yeast torsinA expression system and tested the roles of ER chaperones in mediating the folding and stability of torsinA and torsinAΔE. We discovered that the ER lumenal Hsp70, BiP, an associated Hsp40, Scj1, and a nucleotide exchange factor, Lhs1, stabilize torsinA and torsinAΔE. BiP also maintained torsinA and torsinAΔE solubility. Mutations predicted to compromise specific torsinA functional motifs showed a synthetic interaction with the ΔE mutation and destabilized torsinAΔE, suggesting that the ΔE mutation predisposes torsinA to defects in the presence of secondary insults. In this case, BiP was required for torsinAΔE degradation, consistent with data that specific chaperones exhibit either pro-degradative or pro-folding activities. Finally, using two independent approaches, we established that BiP stabilizes torsinA and torsinAΔE in mammalian cells. Together, these data define BiP as the first identified torsinA chaperone, and treatments that modulate BiP might improve symptoms associated with EOTD. PMID:24627482

Revolution rather than rotation of AAA+ hexameric phi29 nanomotor for viral dsDNA packaging without coiling☆

PubMed Central

Schwartz, Chad; De Donatis, Gian Marco; Zhang, Hui; Fang, Huaming; Guo, Peixuan

2013-01-01

It has long been believed that the DNA-packaging motor of dsDNA viruses utilizes a rotation mechanism. Here we report a revolution rather than rotation mechanism for the bacteriophage phi29 DNA packaging motor. The phi29 motor contains six copies of the ATPase (Schwartz et al., this issue); ATP binding to one ATPase subunit stimulates the ATPase to adopt a conformation with a high affinity for dsDNA. ATP hydrolysis induces a new conformation with a lower affinity, thus transferring the dsDNA to an adjacent subunit by a power stroke. DNA revolves unidirectionally along the hexameric channel wall of the ATPase, but neither the dsDNA nor the ATPase itself rotates along its own axis. One ATP is hydrolyzed in each transitional step, and six ATPs are consumed for one helical turn of 360°. Transition of the same dsDNA chain along the channel wall, but at a location 60° different from the last contact, urges dsDNA to move forward 1.75 base pairs each step (10.5 bp per turn/6ATP=1.75 bp per ATP). Each connector subunit tilts with a left-handed orientation at a 30° angle in relation to its vertical axis that runs anti-parallel to the right-handed dsDNA helix, facilitating the one-way traffic of dsDNA. The connector channel has been shown to cause four steps of transition due to four positively charged lysine rings that make direct contact with the negatively charged DNA phosphate backbone. Translocation of dsDNA into the procapsid by revolution avoids the difficulties during rotation that are associated with DNA supercoiling. Since the revolution mechanism can apply to any stoichiometry, this motor mechanism might reconcile the stoichiometry discrepancy in many phage systems where the ATPase has been found as a tetramer, hexamer, or nonamer. PMID:23763768

The AAA protein Msp1 mediates clearance of excess tail-anchored proteins from the peroxisomal membrane

PubMed Central

Weir, Nicholas R; Kamber, Roarke A; Martenson, James S

2017-01-01

Msp1 is a conserved AAA ATPase in budding yeast localized to mitochondria where it prevents accumulation of mistargeted tail-anchored (TA) proteins, including the peroxisomal TA protein Pex15. Msp1 also resides on peroxisomes but it remains unknown how native TA proteins on mitochondria and peroxisomes evade Msp1 surveillance. We used live-cell quantitative cell microscopy tools and drug-inducible gene expression to dissect Msp1 function. We found that a small fraction of peroxisomal Pex15, exaggerated by overexpression, is turned over by Msp1. Kinetic measurements guided by theoretical modeling revealed that Pex15 molecules at mitochondria display age-independent Msp1 sensitivity. By contrast, Pex15 molecules at peroxisomes are rapidly converted from an initial Msp1-sensitive to an Msp1-resistant state. Lastly, we show that Pex15 interacts with the peroxisomal membrane protein Pex3, which shields Pex15 from Msp1-dependent turnover. In sum, our work argues that Msp1 selects its substrates on the basis of their solitary membrane existence. PMID:28906250

Hda, a novel DnaA-related protein, regulates the replication cycle in Escherichia coli

PubMed Central

Kato, Jun-ichi; Katayama, Tsutomu

2001-01-01

The bacterial DnaA protein binds to the chromosomal origin of replication to trigger a series of initiation reactions, which leads to the loading of DNA polymerase III. In Escherichia coli, once this polymerase initiates DNA synthesis, ATP bound to DnaA is efficiently hydrolyzed to yield the ADP-bound inactivated form. This negative regulation of DnaA, which occurs through interaction with the β-subunit sliding clamp configuration of the polymerase, functions in the temporal blocking of re-initiation. Here we show that the novel DnaA-related protein, Hda, from E.coli is essential for this regulatory inactivation of DnaA in vitro and in vivo. Our results indicate that the hda gene is required to prevent over-initiation of chromosomal replication and for cell viability. Hda belongs to the chaperone-like ATPase family, AAA+, as do DnaA and certain eukaryotic proteins essential for the initiation of DNA replication. We propose that the once-per-cell-cycle rule of replication depends on the timely interaction of AAA+ proteins that comprise the apparatus regulating the activity of the initiator of replication. PMID:11483528

Hda, a novel DnaA-related protein, regulates the replication cycle in Escherichia coli.

PubMed

Kato , J; Katayama, T

2001-08-01

The bacterial DnaA protein binds to the chromosomal origin of replication to trigger a series of initiation reactions, which leads to the loading of DNA polymerase III. In Escherichia coli, once this polymerase initiates DNA synthesis, ATP bound to DnaA is efficiently hydrolyzed to yield the ADP-bound inactivated form. This negative regulation of DnaA, which occurs through interaction with the beta-subunit sliding clamp configuration of the polymerase, functions in the temporal blocking of re-initiation. Here we show that the novel DnaA-related protein, Hda, from E.coli is essential for this regulatory inactivation of DnaA in vitro and in vivo. Our results indicate that the hda gene is required to prevent over-initiation of chromosomal replication and for cell viability. Hda belongs to the chaperone-like ATPase family, AAA(+), as do DnaA and certain eukaryotic proteins essential for the initiation of DNA replication. We propose that the once-per-cell-cycle rule of replication depends on the timely interaction of AAA(+) proteins that comprise the apparatus regulating the activity of the initiator of replication.

A nurse-run clinic for patients with incidentally discovered small abdominal aortic aneurysms is feasible and cost-effective.

PubMed

Griffin, J L; Clarke, G A; Roake, J A; Lewis, D R

2015-04-01

Patients with incidentally discovered small abdominal aortic aneurysms (AAA) require assessment by a vascular surgery department for possible enrollment in a surveillance programme. Our unit implemented a vascular nurse-run AAA clinic in October 2010. The aim of this study was to assess the feasibility of a specialist nurse-run small AAA clinic. Demographic and clinical data were collected prospectively for all patients seen in the new vascular nurse clinic between October 2010 and November 2012. A validated AAA operative mortality score was used to aid decision making by the vascular nurse. Some 250 patients were seen in the clinic. 198 (79.2%) patients were enrolled in surveillance, 40 (16%) declined enrollment and 12 (4.8%) were referred to a consultant clinic for further assessment. The majority of patients were male and the mean age was 73.7 years. Co-morbidities included hypertension, a history of cardiovascular disease, and hyperlipidaemia. The majority of referrals were considered to be low operative risk. No aneurysms ruptured whilst under surveillance. A nurse-run clinic that assesses patients with incidentally discovered small AAAs for inclusion in AAA surveillance is a feasible alternative to assessment of these patients in a consultant-run clinic. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Low Serum Levels of EPA are Associated with the Size and Growth Rate of Abdominal Aortic Aneurysm.

PubMed

Aikawa, Tatsuro; Miyazaki, Tetsuro; Shimada, Kazunori; Sugita, Yurina; Shimizu, Megumi; Ouchi, Shohei; Kadoguchi, Tomoyasu; Yokoyama, Yasutaka; Shiozawa, Tomoyuki; Hiki, Masaru; Takahashi, Shuhei; Al Shahi, Hamad; Dohi, Shizuyuki; Amano, Atsushi; Daida, Hiroyuki

2017-09-01

Omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported to reduce the risk of cardiovascular disease. However, whether omega-3 PUFAs are involved in the pathogenesis of abdominal aortic aneurysms (AAA) remains unclear. We analyzed 67 consecutive patients admitted for the elective surgical repair of AAA. We investigated the association of serum EPA and DHA levels as well as the EPA/AA ratio with the size of AAA assessed using three-dimensional reconstructed computed tomography images. Mean patient age was 70±9 years and 60 patients were male. Serum EPA and DHA levels were 75.2±35.7 μg/mL and 146.1±48.5 μg/mL, respectively. EPA/AA ratio was 0.44±0.22, which was lower than those in healthy Japanese subject and equivalent to those in Japanese patients with coronary artery disease as previously reported. Mean of the maximum AAA diameter was 56.4±8.9 mm, and serum EPA levels and EPA/AA ratio negatively correlated with it (r=-0.32 and r=-0.32, respectively). Multiple liner regression analysis showed that EPA levels were significant independent factor contributing to the maximum AAA diameter. Furthermore, low serum EPA levels and low EPA/AA ratio were significantly associated with the growth rate of AAA diameter (r=-0.43 and r=-0.33, respectively). EPA levels in patients with AAA were relatively low. Low serum EPA levels and EPA/AA ratio were associated with the size and growth rate of AAA.

Cryo-EM of the pathogenic VCP variant R155P reveals long-range conformational changes in the D2 ATPase ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mountassif, Driss; Fabre, Lucien; Zaid, Younes

Single amino acid mutations in valosin containing protein (VCP/p97), a highly conserved member of the ATPases associated with diverse cellular activities (AAA) family of ATPases has been linked to a severe degenerative disease affecting brain, muscle and bone tissue. Previous studies have demonstrated the role of VCP mutations in altering the ATPase activity of the D2 ring; however the structural consequences of these mutations remain unclear. In this study, we report the three-dimensional (3D) map of the pathogenic VCP variant, R155P, as revealed by single-particle Cryo-Electron Microscopy (EM) analysis at 14 Å resolution. We show that the N-terminal R155P mutation inducesmore » a large structural reorganisation of the D2 ATPase ring. Results from docking studies using crystal structure data of available wild-type VCP in the EM density maps indicate that the major difference is localized at the interface between two protomers within the D2 ring. Consistent with a conformational change, the VCP R155P variant shifted the isoelectric point of the protein and reduced its interaction with its well-characterized cofactor, nuclear protein localization-4 (Npl4). Together, our results demonstrate that a single amino acid substitution in the N-terminal domain can relay long-range conformational changes to the distal D2 ATPase ring. Our results provide the first structural clues of how VCP mutations may influence the activity and function of the D2 ATPase ring. - Highlights: • p97{sub R155P} and p97{sub A232E} decrease the ability of p97 to bind to its co-factor Npl4. • p97{sub R155P} has a different isoelectric point than that of p97{sub R95G}, p97{sub A232E} and p97{sub WT}. • Mutation R155P changes principally the conformation of the D2 ring. • Mutation R155P modifies the interface between two protomers within the D2 ring.« less

Multi-Centre Study on Cardiovascular Risk Management on Patients Undergoing AAA Surveillance.

PubMed

Saratzis, A; Dattani, N; Brown, A; Shalhoub, J; Bosanquet, D; Sidloff, D; Stather, P

2017-07-01

The risk of cardiovascular events and death in patients with abdominal aortic aneurysms (AAA) is high. Screening has been introduced to reduce AAA related mortality; however, after AAA diagnosis, cardiovascular modification may be as important to patient outcomes as surveillance. The aim of this study was to assess cardiovascular risk reduction in patients with small AAA. Institutional approval was granted for The Vascular and Endovascular Research Network (VERN) to retrospectively collect data pertaining to cardiovascular risk reduction from four tertiary vascular units in England. Patients with small AAA (January 2013-December 2015) were included. Demographic details, postcode, current medications, and smoking status were recorded using a bespoke electronic database and analysed. In a secondary analysis VERN contacted all AAA screening units in England and Wales to assess their current protocols relating to CV protection. In total, 1053 patients were included (mean age 74 ± 9 years, all men). Of these, 745 patients (70.8%) had been prescribed an antiplatelet agent and 787 (74.7%) a statin. Overall, only 666 patients (63.2%) were prescribed both a statin and antiplatelet. Two hundred and sixty eight patients (32.1%) were current smokers and the proportion of patients who continued to smoke decreased with age. Overall, only 401 patients (48.1%) were prescribed a statin, antiplatelet, and had stopped smoking. In the secondary analysis 38 AAA screening units (84% national coverage) replied. Thirty-one units (82%) suggest changes to the patient's prescription; however, none monitor compliance with these recommendations or assess whether the general practitioner has been made aware of the AAA diagnosis or prescription advice. Many patients with small AAA are not prescribed an antiplatelet/statin, and still smoke cigarettes, and therefore remain at high risk of cardiovascular morbidity and mortality. National guidance to ensure this high risk group of patients is adequately protected from poor cardiovascular outcomes is lacking. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Structural Characterization of a Newly Identified Component of α-Carboxysomes: The AAA+ Domain Protein CsoCbbQ

DOE PAGES

Sutter, Markus; Roberts, Evan W.; Gonzalez, Raul C.; ...

2015-11-05

Carboxysomes are bacterial microcompartments that enhance carbon fixation by concentrating ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and its substrate CO 2 within a proteinaceous shell. They are found in all cyanobacteria, some purple photoautotrophs and many chemoautotrophic bacteria. Carboxysomes consist of a protein shell that encapsulates several hundred molecules of RuBisCO, and contain carbonic anhydrase and other accessory proteins. Genes coding for carboxysome shell components and the encapsulated proteins are typically found together in an operon. The α-carboxysome operon is embedded in a cluster of additional, conserved genes that are presumably related to its function. In many chemoautotrophs, products of the expanded carboxysomemore » locus include CbbO and CbbQ, a member of the AAA+ domain superfamily. We bioinformatically identified subtypes of CbbQ proteins and show that their genes frequently co-occur with both Form IA and Form II RuBisCO. The α-carboxysome-associated ortholog, CsoCbbQ, from Halothiobacillus neapolitanus forms a hexamer in solution and hydrolyzes ATP. The crystal structure shows that CsoCbbQ is a hexamer of the typical AAA+ domain; the additional C-terminal domain, diagnostic of the CbbQ subfamily, structurally fills the inter-monomer gaps, resulting in a distinctly hexagonal shape. Finally, we show that CsoCbbQ interacts with CsoCbbO and is a component of the carboxysome shell, the first example of ATPase activity associated with a bacterial microcompartment.« less

Polymorphisms of the interleukin-6 gene promoter and abdominal aortic aneurysm.

PubMed

Smallwood, L; Allcock, R; van Bockxmeer, F; Warrington, N; Palmer, L J; Iacopetta, B; Norman, P E

2008-01-01

Elevated levels of circulating interleukin-6 (IL-6) have been reported in patients with abdominal aortic aneurysms (AAAs). Although this implicates inflammation as a cause of AAAs, there is also evidence that the aneurysmal aorta may secrete IL-6 into the circulation as a result of aortic proteolysis. Genetic association studies are one means of trying to clarify the role of specific mediators in the causal pathway. The aim of the present study was to examine the association between variants of the IL-6 gene and AAAs. An association study involving 677 men with screen-detected AAAs and 656 age-matched controls was performed. Three variants in the IL-6 promoter region were analysed: IL-6-174G>C (rs1800795), IL-6-572G>C (rs1800796) and IL-6-597G>A (rs1800797). Univariate regression of SNP genotype on AAA as a binary outcome was initially performed under a range of genetic models (additive, dominant and recessive). This was followed by multivariate analyses, testing the same models but including risk factors known to be associated with AAAs. All analyses and haplotype estimation were performed under a generalized linear model framework. IL-6-572G>C polymorphism (frequency 1.5% in cases) was identified as an independent risk factor for AAA with an odds ratio (OR) of 6.00 (95%CI: 1.22, 29.41) when applied to the recessive model. No association was seen in the additive or dominant models. In a multivariate analysis using the most common haplotype (h.111, frequency 48.7%) as a reference, h.211 (frequency 4.4%) was an independent risk factor for AAA (OR 1.56, 95%CI: 1.02, 2.39). The IL-6 572G>C polymorphism (and h.211 haplotype) is associated with AAA, however it is too rare to be an important cause of most AAAs. This does not support the concept that the elevated level of IL-6 reported in patients with AAAs is a primary cause of the aneurysmal process.

Purification and properties of an ATPase from Sulfolobus solfataricus

NASA Technical Reports Server (NTRS)

Hochstein, Lawrence I.; Stan-Lotter, Helga

1992-01-01

The paper reports properties of a sulfite-activated ATPase from Sulfolobus solfataricus, purified using ammonium sulfate precipitation, column chromatography on UltraGel and Sepharose 6B, and SDS-PAGE. The 92-fold purified enzyme had a relative molecular mass of 370,000. It could be dissociated into three subunits with respective molecular masses of 63,000, 48,000, and 24,000. The ATPase activity was found to be inhibitable by nitrate, N-ethylmaleimide (which bound predominantly to the largest subunit), and 4-chloro 7-nitrobenzofurazan, but not by azide, quercetin, or vanadate. While the ATPase from S. solfataricus shared a number of properties with the S. acidocaldarius ATPase, there were also significant differences suggesting the existence of several types of archaeal ATPases.

Vfa1 binds to the N-terminal microtubule-interacting and trafficking (MIT) domain of Vps4 and stimulates its ATPase activity.

PubMed

Vild, Cody J; Xu, Zhaohui

2014-04-11

The endosomal sorting complexes required for transport (ESCRT) are responsible for multivesicular body biogenesis, membrane abscission during cytokinesis, and retroviral budding. They function as transiently assembled molecular complexes on the membrane, and their disassembly requires the action of the AAA-ATPase Vps4. Vps4 is regulated by a multitude of ESCRT and ESCRT-related proteins. Binding of these proteins to Vps4 is often mediated via the microtubule-interacting and trafficking (MIT) domain of Vps4. Recently, a new Vps4-binding protein Vfa1 was identified in a yeast genetic screen, where overexpression of Vfa1 caused defects in vacuolar morphology. However, the function of Vfa1 and its role in vacuolar biology were largely unknown. Here, we provide the first detailed biochemical and biophysical study of Vps4-Vfa1 interaction. The MIT domain of Vps4 binds to the C-terminal 17 residues of Vfa1. This interaction is of high affinity and greatly stimulates the ATPase activity of Vps4. The crystal structure of the Vps4-Vfa1 complex shows that Vfa1 adopts a canonical MIT-interacting motif 2 structure that has been observed previously in other Vps4-ESCRT interactions. These findings suggest that Vfa1 is a novel positive regulator of Vps4 function.

Vfa1 Binds to the N-terminal Microtubule-interacting and Trafficking (MIT) Domain of Vps4 and Stimulates Its ATPase Activity*

PubMed Central

Vild, Cody J.; Xu, Zhaohui

2014-01-01

The endosomal sorting complexes required for transport (ESCRT) are responsible for multivesicular body biogenesis, membrane abscission during cytokinesis, and retroviral budding. They function as transiently assembled molecular complexes on the membrane, and their disassembly requires the action of the AAA-ATPase Vps4. Vps4 is regulated by a multitude of ESCRT and ESCRT-related proteins. Binding of these proteins to Vps4 is often mediated via the microtubule-interacting and trafficking (MIT) domain of Vps4. Recently, a new Vps4-binding protein Vfa1 was identified in a yeast genetic screen, where overexpression of Vfa1 caused defects in vacuolar morphology. However, the function of Vfa1 and its role in vacuolar biology were largely unknown. Here, we provide the first detailed biochemical and biophysical study of Vps4-Vfa1 interaction. The MIT domain of Vps4 binds to the C-terminal 17 residues of Vfa1. This interaction is of high affinity and greatly stimulates the ATPase activity of Vps4. The crystal structure of the Vps4-Vfa1 complex shows that Vfa1 adopts a canonical MIT-interacting motif 2 structure that has been observed previously in other Vps4-ESCRT interactions. These findings suggest that Vfa1 is a novel positive regulator of Vps4 function. PMID:24567329

Patients with abdominal aortic aneurysm have a high prevalence of popliteal artery aneurysms.

PubMed

Tuveson, Viktoria; Löfdahl, Hedvig E; Hultgren, Rebecka

2016-08-01

Patients with abdominal aortic aneurysms (AAA) are more prone to develop popliteal artery aneurysms (PAA), but the prevalence is not well known. Our aim was to investigate the prevalence of PAA in patients with AAA, and to determine whether a certain risk factor profile is more commonly found in patients with concurrent aneurysms. All AAA patients (ICD code I71.3, I71.4) attending the outpatient clinic at the Karolinska University Hospital between 2011 and 2013 were included in the study cohort (n=465); 48% (225) had been subjected to an ultrasound or computed tomography scan of their popliteal arteries. In these patients, three definitions of PAA were considered (⩾ 10.5, ⩾ 12, ⩾ 15 mm), although the overall analysis is based on PAA ⩾ 12 mm. The mean age was 70.7 years (SD 7.5), 89% were men, and the mean AAA diameter was 47 mm (SD 14). The prevalence of PAA was 19% (n=43) by definition ⩾ 12 mm, and 11% (n=25) with 15 mm. Claudication was more frequently found in AAA patients with PAA than patients without PAA. Sensitivity between clinical examination and radiology was 26%, and the specificity for clinical examination was 90%. In conclusion, owing to the high prevalence of PAA in AAA patients, described by us and others, the low cost and risks associated with ultrasound and the poor sensitivity at clinical examination, all women and men with AAA should undergo one radiological examination of their popliteal arteries. © The Author(s) 2016.

Targeting Hsp90-Cdc37: A Promising Therapeutic Strategy by Inhibiting Hsp90 Chaperone Function.

PubMed

Wang, Lei; Li, Li; Gu, Kai; Xu, Xiao-Li; Sun, Yuan; You, Qi-Dong

2017-01-01

The Hsp90 chaperone protein regulates the folding, maturation and stability of a wide variety of oncoproteins. In recent years, many Hsp90 inhibitors have entered into the clinical trials while all of them target ATPase showing similar binding capacity and kinds of side-effects so that none have reached to the market. During the regulation progress, numerous protein- protein interactions (PPI) such as Hsp90 and client proteins or cochaperones are involved. With the Hsp90-cochaperones PPI networks being more and more clear, many cancerous proteins have been reported to be tightly correlated to Hsp90-cochaperones PPI. Among them, Hsp90-Cdc37 PPI has been widely reported to associate with numerous protein kinases, making it a novel target for the treatment of cancers. In this paper, we briefly review the strategies and modulators targeting Hsp90-Cdc37 complex including direct and indirect regulation mechanism. Through these discussions we expect to present inspirations for new insights into an alternative way to inhibit Hsp90 chaperone function. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

NASA Airborne Astronomy Ambassadors (AAA)

NASA Astrophysics Data System (ADS)

Backman, D. E.; Harman, P. K.; Clark, C.

2016-12-01

NASA's Airborne Astronomy Ambassadors (AAA) is a three-part professional development (PD) program for high school physics and astronomy teachers. The AAA experience consists of: (1) blended-learning professional development composed of webinars, asynchronous content learning, and a series of hands-on workshops (2) a STEM immersion experience at NASA Armstrong Flight Research Center's B703 science research aircraft facility in Palmdale, California, and (3) ongoing participation in the AAA community of practice (CoP) connecting participants with astrophysics and planetary science Subject Matter Experts (SMEs). The SETI Institute (SI) is partnering with school districts in Santa Clara and Los Angeles Counties during the AAA program's "incubation" period, calendar years 2016 through 2018. AAAs will be selected by the school districts based on criteria developed during spring 2016 focus group meetings led by the program's external evaluator, WestEd.. Teachers with 3+ years teaching experience who are assigned to teach at least 2 sections in any combination of the high school courses Physics (non-AP), Physics of the Universe (California integrated model), Astronomy, or Earth & Space Sciences are eligible. Partner districts will select at least 48 eligible applicants with SI oversight. WestEd will randomly assign selected AAAs to group A or group B. Group A will complete PD in January - June of 2017 and then participate in SOFIA science flights during fall 2017 (SOFIA Cycle 5). Group B will act as a control during the 2017-18 school year. Group B will then complete PD in January - June of 2018 and participate in SOFIA science flights in fall 2018 (Cycle 6). Under the current plan, opportunities for additional districts to seek AAA partnerships with SI will be offered in 2018 or 2019. A nominal two-week AAA curriculum component will be developed by SI for classroom delivery that will be aligned with selected California Draft Science Framework Disciplinary Core Ideas, Crosscutting Concepts, and Science and Engineering Practices. (The California Draft Framework in turn is aligned with NGSS). The AAA program will demonstrate student gains in standards-based student learning, measure changes in student attitudes towards STEM, and observe & record Ambassadors' implementation of curricular changes.

MCM: one ring to rule them all.

PubMed

Deegan, Tom D; Diffley, John F X

2016-04-01

Precise replication of the eukaryotic genome is achieved primarily through strict regulation of the enzyme responsible for DNA unwinding, the replicative helicase. The motor of this helicase is a hexameric AAA+ ATPase called MCM. The loading of MCM onto DNA and its subsequent activation and disassembly are each restricted to separate cell cycle phases; this ensures that a functional replisome is only built once at any replication origin. In recent years, biochemical and structural studies have shown that distinct conformational changes in MCM, each requiring post-translational modifications and/or the activity of other replication proteins, define the various stages of the chromosome replication cycle. Here, we review recent progress in this area. Copyright © 2016. Published by Elsevier Ltd.

X-ray Crystal Structures of the Type IVb Secretion System DotB ATPases.

PubMed

Prevost, Marie S; Waksman, Gabriel

2018-05-17

Human infections by the intracellular bacterial pathogen Legionella pneumophila result in a severe form of pneumonia, the Legionnaire's disease. L. pneumophila utilises a type IVb secretion (T4bS) system termed "dot/icm" to secrete protein effectors to the host cytoplasm. The dot/icm system is powered at least in part by a functionally critical AAA+ ATPase, a protein called DotB, thought to belong to the VirB11 family of proteins. Here we present the crystal structure of DotB at 3.19 Å resolution, in its hexameric form. We observe that DotB is in fact a structural intermediate between VirB11 and PilT family proteins, with a PAS-like N-terminal domain coupled to a RecA-like C-terminal domain. It also shares critical structural elements only found in PilT. The structure also reveals two conformers, termed α and β, with an αβαβαβ configuration. The existence of α and β conformers in this class of proteins was confirmed by solving the structure of DotB from another bacterial pathogen, Yersinia, where, intriguingly, we observed an ααβααβ configuration. The two conformers co-exist regardless of the nucleotide-bound states of the proteins. Our investigation therefore reveals that these ATPases can adopt a wider range of conformational states than was known before, shedding new light on the extraordinary spectrum of conformations these ATPases can access to carry out their function. Overall, the structure of DotB provides a template for further rational drug-design to develop more specific antibiotics to tackle Legionnaire's disease. This article is protected by copyright. All rights reserved. © 2018 The Protein Society.

Down-regulated Na+/K+-ATPase activity in ischemic penumbra after focal cerebral ischemia/reperfusion in rats

PubMed Central

Huang, Hao; Chen, Yang-Mei; Zhu, Fei; Tang, Shi-Ting; Xiao, Ji-Dong; Li, Lv-Li; Lin, Xin-Jing

2015-01-01

This study was aimed to examine whether the Na+/K+ adenosine triphosphatase (Na+/K+-ATPase) activity in ischemic penumbra is associated with the pathogenesis of ischemia/reperfusion-induced brain injury. An experimental model of cerebral ischemia/reperfusion was made by transient middle cerebral artery occlusion (tMCAO) in rats and the changes of Na+/K+-ATPase activity in the ischemic penumbra was examined by Enzyme Assay Kit. Extensive infarction was observed in the frontal and parietal cortical and subcortical areas at 6 h, 24 h, 48 h, 3 d and 7 d after tMCAO. Enzyme Assay analyses revealed the activity of Na+/K+-ATPase was decreased in the ischemic penumbra of model rats after focal cerebral ischemia/reperfusion compared with sham-operated rats, and reduced to its minimum at 48 h, while the infarct volume was enlarged gradually. In addition, accompanied by increased brain water content, apoptosis-related bcl-2 and Bax proteins, apoptotic index and neurologic deficits Longa scores, but fluctuated the ratio of bcl-2/Bax. Correlation analysis showed that the infarct volume, apoptotic index, neurologic deficits Longa scores and brain water content were negatively related with Na+/K+-ATPase activity, while the ratio of bcl-2/Bax was positively related with Na+/K+-ATPase activity. Our results suggest that down-regulated Na+/K+-ATPase activity in ischemic penumbra might be involved in the pathogenesis of cerebral ischemia/reperfusion injury presumably through the imbalance ratio of bcl-2/Bax and neuronal apoptosis, and identify novel target for neuroprotective therapeutic intervention in cerebral ischemic disease. PMID:26722460

Sex differences in mortality after abdominal aortic aneurysm repair in the UK

PubMed Central

Saratzis, A.; Sweeting, M. J.; Michaels, J.; Powell, J. T.; Thompson, S. G.; Bown, M. J.

2017-01-01

Background The UK abdominal aortic aneurysm (AAA) screening programmes currently invite only men for screening because the benefit in women is uncertain. Perioperative risk is critical in determining the effectiveness of screening, and contemporary estimates of these risks in women are lacking. The aim of this study was to compare mortality following AAA repair between women and men in the UK. Methods Anonymized data from the UK National Vascular Registry (NVR) for patients undergoing AAA repair (January 2010 to December 2014) were analysed. Co‐variables were extracted for analysis by sex. The primary outcome measure was in‐hospital mortality. Secondary outcome measures included mortality by 5‐year age groups and duration of hospital stay. Logistic regression was performed to adjust for age, calendar time, AAA diameter and smoking status. NVR‐based outcomes were checked against Hospital Episode Statistics (HES) data. Results A total of 23 245 patients were included (13·0 per cent women). Proportionally, more women than men underwent open repair. For elective open AAA repair, the in‐hospital mortality rate was 6·9 per cent in women and 4·0 per cent in men (odds ratio (OR) 1·48, 95 per cent c.i. 1·08 to 2·02; P = 0·014), whereas for elective endovascular AAA repair it was 1·8 per cent in women and 0·7 per cent in men (OR 2·86, 1·72 to 4·74; P < 0·001); the results in HES were similar. For ruptured AAA, there was no sex difference in mortality within the NVR; however, in HES, for ruptured open AAA repair, the in‐hospital mortality rate was higher in women (33·6 versus 27·1 per cent; OR 1·36, 1·16 to 1·59; P < 0·001). Conclusion Women have a higher in‐hospital mortality rate than men after elective AAA repair even after adjustment. This higher mortality may have an impact on the benefit offered by any screening programme offered to women. PMID:28745403

Effects of Animal-Assisted Activities with Guinea Pigs in the Primary School Classroom

PubMed Central

O’Haire, Marguerite E.; McKenzie, Samantha J.; McCune, Sandra; Slaughter, Virginia

2013-01-01

This study investigated the effects of a classroom-based animal-assisted activities (AAA) program with guinea pigs on the social functioning of primary school children. We hypothesized that participants in the experimental condition (n = 64), compared with a waitlist control group (n = 64), would demonstrate improvements in social functioning following the program. Parents and teachers used the Social Skills Rating System (SSRS) to evaluate the social skills and problem behaviors of 128 participating children (age range = 4.8 to 12.7 years) before and after an 8-week period. Teachers also rated academic competence at both time points. Children who participated in the AAA program demonstrated significantly greater improvements in social functioning than their control group peers, as defined by greater increases in social skills (teacher SSRS) and decreases in problem behaviors (parent and teacher SSRS). There were no significant differences between the groups in academic competence. AAA participants demonstrated significant increases in social skills and decreases in problem behaviors from pre- to post-program on the teacher version of the SSRS. Control group participants did not show significant changes on these measures. These findings suggest that an AAA program with guinea pigs may be a feasible addition to the primary school classroom in order to improve social functioning. Further component analysis will be necessary to determine whether the animal is the active ingredient in AAA programs of this nature. PMID:24265514

Purification and Properties of an ATPase from Sulfolobus solfataricus

NASA Technical Reports Server (NTRS)

Hochstein, Lawrence I.; Stan-Lotter, Helga

1992-01-01

A sulfite-activated ATPase isolated from Sulfolobus solfataricus had a relative molecular mass of 370,000. It was composed of three subunits whose relative molecular masses were 63,000, 48,000, and 24,000. The enzyme was inhibited by the vacuolar ATPase inhibitors nitrate and N-ethylmaleimide; 4-chloro-7-nitrobenzo-furazan (NBD-Cl) was also inhibitory. N-Ethylmaleimide was predominately bound to the largest subunit while NBD-CL was bound to both subunits. ATPase activity was inhibited by low concentrations of p-chloromercuri-phenyl sulfonate and the inhibition was reversed by cysteine which suggested that thiol groups were essential for activity. While the ATPase from S. solfataricus shared several properties with the ATPase from S. acidocaldarius there were significant differences. The latter enzyme was activated by sulfate and chloride and was unaffected by N-ethylmaleimide, whereas the S. solfataricus ATPase was inhibited by these anions as well as N-ethyimaleimide. These differences as well as differences that occur in other vacuolar-like ATPases isolated from the methanogenic and the extremely halophilic bacteria suggest the existence of several types of archaeal ATPases, none of which have been demonstrated to synthesize ATP.

The antibiotic cyclomarin blocks arginine-phosphate-induced millisecond dynamics in the N-terminal domain of ClpC1 from Mycobacterium tuberculosis.

PubMed

Weinhäupl, Katharina; Brennich, Martha; Kazmaier, Uli; Lelievre, Joel; Ballell, Lluis; Goldberg, Alfred; Schanda, Paul; Fraga, Hugo

2018-06-01

Mycobacterium tuberculosis can remain dormant in the host, an ability that explains the failure of many current tuberculosis treatments. Recently, the natural products cyclomarin, ecumicin, and lassomycin have been shown to efficiently kill Mycobacterium tuberculosis persisters. Their target is the N-terminal domain of the hexameric AAA+ ATPase ClpC1, which recognizes, unfolds, and translocates protein substrates, such as proteins containing phosphorylated arginine residues, to the ClpP1P2 protease for degradation. Surprisingly, these antibiotics do not inhibit ClpC1 ATPase activity, and how they cause cell death is still unclear. Here, using NMR and small-angle X-ray scattering, we demonstrate that arginine-phosphate binding to the ClpC1 N-terminal domain induces millisecond dynamics. We show that these dynamics are caused by conformational changes and do not result from unfolding or oligomerization of this domain. Cyclomarin binding to this domain specifically blocked these N-terminal dynamics. On the basis of these results, we propose a mechanism of action involving cyclomarin-induced restriction of ClpC1 dynamics, which modulates the chaperone enzymatic activity leading eventually to cell death. © 2018 Weinhäupl et al.

Mutations in SPATA5 Are Associated with Microcephaly, Intellectual Disability, Seizures, and Hearing Loss.

PubMed

Tanaka, Akemi J; Cho, Megan T; Millan, Francisca; Juusola, Jane; Retterer, Kyle; Joshi, Charuta; Niyazov, Dmitriy; Garnica, Adolfo; Gratz, Edward; Deardorff, Matthew; Wilkins, Alisha; Ortiz-Gonzalez, Xilma; Mathews, Katherine; Panzer, Karin; Brilstra, Eva; van Gassen, Koen L I; Volker-Touw, Catharina M L; van Binsbergen, Ellen; Sobreira, Nara; Hamosh, Ada; McKnight, Dianalee; Monaghan, Kristin G; Chung, Wendy K

2015-09-03

Using whole-exome sequencing, we have identified in ten families 14 individuals with microcephaly, developmental delay, intellectual disability, hypotonia, spasticity, seizures, sensorineural hearing loss, cortical visual impairment, and rare autosomal-recessive predicted pathogenic variants in spermatogenesis-associated protein 5 (SPATA5). SPATA5 encodes a ubiquitously expressed member of the ATPase associated with diverse activities (AAA) protein family and is involved in mitochondrial morphogenesis during early spermatogenesis. It might also play a role in post-translational modification during cell differentiation in neuronal development. Mutations in SPATA5 might affect brain development and function, resulting in microcephaly, developmental delay, and intellectual disability. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Structural characterization of the bacterial proteasome homolog BPH reveals a tetradecameric double-ring complex with unique inner cavity properties.

PubMed

Fuchs, Adrian C D; Maldoner, Lorena; Hipp, Katharina; Hartmann, Marcus D; Martin, Jörg

2018-01-19

Eukaryotic and archaeal proteasomes are paradigms for self-compartmentalizing proteases. To a large extent, their function requires interplay with hexameric ATPases associated with diverse cellular activities (AAA+) that act as substrate unfoldases. Bacteria have various types of self-compartmentalizing proteases; in addition to the proteasome itself, these include the proteasome homolog HslV, which functions together with the AAA+ HslU; the ClpP protease with its partner AAA+ ClpX; and Anbu, a recently characterized ancestral proteasome variant. Previous bioinformatic analysis has revealed a novel bacterial member of the proteasome family Betaproteobacteria proteasome homolog (BPH). Using cluster analysis, we here affirmed that BPH evolutionarily descends from HslV. Crystal structures of the Thiobacillus denitrificans and Cupriavidus metallidurans BPHs disclosed a homo-oligomeric double-ring architecture in which the active sites face the interior of the cylinder. Using small-angle X-ray scattering (SAXS) and electron microscopy averaging, we found that BPH forms tetradecamers in solution, unlike the dodecamers seen in HslV. Although the highly acidic inner surface of BPH was in striking contrast to the cavity characteristics of the proteasome and HslV, a classical proteasomal reaction mechanism could be inferred from the covalent binding of the proteasome-specific inhibitor epoxomicin to BPH. A ligand-bound structure implied that the elongated BPH inner pore loop may be involved in substrate recognition. The apparent lack of a partner unfoldase and other unique features, such as Ser replacing Thr as the catalytic residue in certain BPH subfamilies, suggest a proteolytic function for BPH distinct from those of known bacterial self-compartmentalizing proteases. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Structural characterization of the bacterial proteasome homolog BPH reveals a tetradecameric double-ring complex with unique inner cavity properties

PubMed Central

Fuchs, Adrian C. D.; Maldoner, Lorena; Hipp, Katharina; Hartmann, Marcus D.; Martin, Jörg

2018-01-01

Eukaryotic and archaeal proteasomes are paradigms for self-compartmentalizing proteases. To a large extent, their function requires interplay with hexameric ATPases associated with diverse cellular activities (AAA+) that act as substrate unfoldases. Bacteria have various types of self-compartmentalizing proteases; in addition to the proteasome itself, these include the proteasome homolog HslV, which functions together with the AAA+ HslU; the ClpP protease with its partner AAA+ ClpX; and Anbu, a recently characterized ancestral proteasome variant. Previous bioinformatic analysis has revealed a novel bacterial member of the proteasome family Betaproteobacteria proteasome homolog (BPH). Using cluster analysis, we here affirmed that BPH evolutionarily descends from HslV. Crystal structures of the Thiobacillus denitrificans and Cupriavidus metallidurans BPHs disclosed a homo-oligomeric double-ring architecture in which the active sites face the interior of the cylinder. Using small-angle X-ray scattering (SAXS) and electron microscopy averaging, we found that BPH forms tetradecamers in solution, unlike the dodecamers seen in HslV. Although the highly acidic inner surface of BPH was in striking contrast to the cavity characteristics of the proteasome and HslV, a classical proteasomal reaction mechanism could be inferred from the covalent binding of the proteasome-specific inhibitor epoxomicin to BPH. A ligand-bound structure implied that the elongated BPH inner pore loop may be involved in substrate recognition. The apparent lack of a partner unfoldase and other unique features, such as Ser replacing Thr as the catalytic residue in certain BPH subfamilies, suggest a proteolytic function for BPH distinct from those of known bacterial self-compartmentalizing proteases. PMID:29183996

9-AAA inhibits growth and induces apoptosis in human melanoma A375 and rat prostate adenocarcinoma AT-2 and Mat-LyLu cell lines but does not affect the growth and viability of normal fibroblasts.

PubMed

Korohoda, Włodzimierz; Hapek, Anna; Pietrzak, Monika; Ryszawy, Damian; Madeja, Zbigniew

2016-11-01

The present study found that, similarly to 5-fluorouracil, low concentrations (1-10 µM) of 9-aminoacridine (9-AAA) inhibited the growth of the two rat prostate cancer AT-2 and Mat-LyLu cell lines and the human melanoma A375 cell line. However, at the same concentrations, 9-AAA had no effect on the growth and apoptosis of normal human skin fibroblasts (HSFs). The differences between the cellular responses of the AT-2 and Mat-LyLu cell lines, which differ in malignancy, were found to be relatively small compared with the differences between normal HSFs and the cancer cell lines. Visible effects on the cell growth and survival of tumor cell lines were observed after 24-48 h of treatment with 9-AAA, and increased over time. The inhibition of cancer cell growth was found to be due to the gradually increasing number of cells dying by apoptosis, which was observed using two methods, direct counting and FlowSight analysis. Simultaneously, cell motile activity decreased to the same degree in cancer and normal cells within the first 8 h of incubation in the presence of 9-AAA. The results presented in the current study suggest that short-lasting tests for potential anticancer substances can be insufficient; which may result in cell type-dependent differences in the responses of cells to tested compounds that act with a delay being overlooked. The observed differences in responses between normal human fibroblasts and cancer cells to 9-AAA show the requirement for additional studies to be performed simultaneously on differently reacting cancer and normal cells, to determine the molecular mechanisms responsible for these differences.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pacaci, P; Cebe, M; Mabhouti, H

Purpose: In this study, dosimetric comparison of field in field (FIF) and intensity modulated radiation therapy (IMRT) techniques used for treatment of whole breast radiotherapy (WBRT) were made. The dosimetric accuracy of treatment planning system (TPS) for Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) algorithms in predicting PTV and OAR doses was also investigated. Methods: Two different treatment planning techniques of left-sided breast cancer were generated for rando phantom. FIF and IMRT plans were compared for doses in PTV and OAR volumes including ipsilateral lung, heart, left ascending coronary artery, contralateral lung and the contralateral breast. PTV and OARsmore » doses and homogeneity and conformality indexes were compared between two techniques. The accuracy of TPS dose calculation algorithms was tested by comparing PTV and OAR doses measured by thermoluminescent dosimetry with the dose calculated by the TPS using AAA and AXB for both techniques. Results: IMRT plans had better conformality and homogeneity indexes than FIF technique and it spared OARs better than FIF. While both algorithms overestimated PTV doses they underestimated all OAR doses. For IMRT plan, PTV doses, overestimation up to 2.5 % was seen with AAA algorithm but it decreased to 1.8 % when AXB algorithm was used. Based on the results of the anthropomorphic measurements for OAR doses, underestimation greater than 7 % is possible by the AAA. The results from the AXB are much better than the AAA algorithm. However, underestimations of 4.8 % were found in some of the points even for AXB. For FIF plan, similar trend was seen for PTV and OARs doses in both algorithm. Conclusion: When using the Eclipse TPS for breast cancer, AXB the should be used instead of the AAA algorithm, bearing in mind that the AXB may still underestimate all OAR doses.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshikatsu, Yuki; Ishida, Yo-ichi; Sudo, Haruka

Nuclear VCP-like 2 (NVL2) is a member of the chaperone-like AAA-ATPase family and is involved in the biosynthesis of 60S ribosomal subunits in mammalian cells. We previously showed the interaction of NVL2 with a DExD/H-box RNA helicase MTR4/DOB1, which is a known cofactor for an exoribonuclease complex, the exosome. This finding implicated NVL2 in RNA metabolic processes during ribosome biogenesis. In the present study, we found that a series of mutations within the ATPase domain of NVL2 causes a defect in pre-rRNA processing into mature 28S and 5.8S rRNAs. Co-immunoprecipitation analysis showed that NVL2 was associated with the nuclear exosomemore » complex, which includes RRP6 as a nucleus-specific catalytic subunit. This interaction was prevented by depleting either MTR4 or RRP6, indicating their essential role in mediating this interaction with NVL2. Additionally, knockdown of MPP6, another cofactor for the nuclear exosome, also prevented the interaction by causing MTR4 to dissociate from the nuclear exosome. These results suggest that NVL2 is involved in pre-rRNA processing by associating with the nuclear exosome complex and that MPP6 is required for maintaining the integrity of this rRNA processing complex. - Highlights: • ATPase-deficient mutants of NVL2 have decreased pre-rRNA processing. • NVL2 associates with the nuclear exosome through interactions with MTR4 and RRP6. • MPP6 stabilizes MTR4-RRP6 interaction and allows NVL2 to interact with the complex.« less

Elimination of cdc2 phosphorylation sites in the cdc25 phosphatase blocks initiation of M-phase.

PubMed Central

Izumi, T; Maller, J L

1993-01-01

The cdc25 phosphatase is a mitotic inducer that activates p34cdc2 at the G2/M transition by dephosphorylation of Tyr15 in p34cdc2. cdc25 itself is also regulated through periodic changes in its phosphorylation state. To elucidate the mechanism for induction of mitosis, phosphorylation of cdc25 has been investigated using recombinant proteins. cdc25 is phosphorylated by both cyclin A/p34cdc2 and cyclin B/p34cdc2 at similar sets of multiple sites in vitro. This phosphorylation retards its electrophoretical mobility and activates its ability to increase cyclin B/p34cdc2 kinase activity three- to fourfold in vitro, as found for endogenous Xenopus cdc25 in M-phase extracts. The threonine and serine residues followed by proline that are conserved between Xenopus and human cdc25 have been mutated. Both the triple mutation of Thr48, Thr67, and Thr138 and the quintuple mutation of these three threonine residues plus Ser205 and Ser285, almost completely abolish the shift in electrophoretic mobility of cdc25 after incubation with M-phase extracts or phosphorylation by p34cdc2. These mutations inhibit the activation of cdc25 by phosphorylation with p34cdc2 by 70 and 90%, respectively. At physiological concentrations these mutants cannot activate cyclin B/p34cdc2 in cdc25-immunodepleted oocyte extracts, suggesting that a positive feed-back loop between cdc2 and cdc25 is necessary for the full activation of cyclin B/p34cdc2 that induces abrupt entry into mitosis in vivo. Images PMID:7513216

Characterization of a heavy metal translocating P-type ATPase gene from an environmental heavy metal resistance Enterobacter sp. isolate.

PubMed

Chien, Chih-Ching; Huang, Chia-Hsuan; Lin, Yi-Wei

2013-03-01

Heavy metals are common contaminants found in polluted areas. We have identified a heavy metal translocating P-type ATPase gene (hmtp) via fosmid library and in vitro transposon mutagenesis from an Enterobacter sp. isolate. This gene is believed to participate in the bacterium's heavy metal resistance traits. The complete gene was identified, cloned, and expressed in a suitable Escherichia coli host cell. E. coli W3110, RW3110 (zntA::Km), GG48 (ΔzitB::Cm zntA::Km), and GG51 (ΔzitB::Cm) were used to study the possible effects of this gene for heavy metal (cadmium and zinc in particular) resistance. Among the E. coli strains tested, RW3110 and GG48 showed more sensitivity to cadmium and zinc compared to the wild-type E. coli W3110 and strain GG51. Therefore, strains RW3110 and GG48 were chosen for the reference hosts for further evaluation of the gene's effect. The results showed that expression of this heavy metal translocating P-type ATPase gene could increase the ability for zinc and cadmium resistance in the tested microorganisms.

Analysis of the microstructure and mechanical performance of composite resins after accelerated artificial aging.

PubMed

De Oliveira Daltoé, M; Lepri, C Penazzo; Wiezel, J Guilherme G; Tornavoi, D Cremonezzi; Agnelli, J A Marcondes; Reis, A Cândido Dos

2013-03-01

Researches that assess the behavior of dental materials are important for scientific and industrial development especially when they are tested under conditions that simulate the oral environment, so this work analyzed the compressive strength and microstructure of three composite resins subjected to accelerated artificial aging (AAA). Three composites resins of 3M (P90, P60 and Z100) were analyzed and were obtained 16 specimens for each type (N.=48). Half of each type were subjected to UV-C system AAA and then were analyzed the surfaces of three aged specimens and three not aged of each type through the scanning electron microscope (SEM). After, eight specimens of each resin, aged and not aged, were subjected to compression test. After statistical analysis of compressive strength values, it was found that there was difference between groups (α <0.05). The resin specimens aged P60 presented lower values of compressive strength statistically significant when compared to the not subject to the AAA. For the other composite resins, there was no difference, regardless of aging, a fact confirmed by SEM. The results showed that the AAA influenced the compressive strength of the resin aged P60; confirmed by surface analysis by SEM, which showed greater structural disarrangement on surface material.

Correlation between atmospheric pressure changes and abdominal aortic aneurysm rupture: results of a single-center study.

PubMed

Molacek, Jiri; Treska, Vladislav; Kasik, Miroslav; Houdek, Karel; Baxa, Jan

2013-09-01

There is much interest in all factors that influence the etiopathogenesis of abdominal aortic aneurysm (AAA) rupture. Apart from the well-established factors such as arterial hypertension, smoking, age, and genetic predisposition, less common factors that may play a role in the mechanism of the rupture are the subject of much discussion. These include atmospheric conditions, temperature, and atmospheric pressure. We conducted this study to investigate the effects of the absolute value of atmospheric pressure and its changes on the frequency of AAA rupture. We retrospectively examined 54 patients who underwent treatment for a ruptured AAA at the Clinic of Surgery in the University Hospital in Pilsen between 1 January 2005 and 31 December 2009. We collected data on the atmospheric pressure in this period from the Czech Hydrometeorological Institute in Pilsen. We did not find a significant difference in atmospheric pressure values between the days when the rupture occurred versus the other days (p < 0.5888). Moreover, we did not find significant changes in the atmospheric pressure during the 48 h preceding the rupture (Student's test p < 0.4434) versus the day of rupture or in the mean atmospheric pressure in that month. These findings suggest that atmospheric pressure and its changes do not affect the pathogenesis of AAA rupture.

Cdt1 stabilizes an open MCM ring for helicase loading.

PubMed

Frigola, Jordi; He, Jun; Kinkelin, Kerstin; Pye, Valerie E; Renault, Ludovic; Douglas, Max E; Remus, Dirk; Cherepanov, Peter; Costa, Alessandro; Diffley, John F X

2017-06-23

ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2-5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC-Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure.

Cdt1 stabilizes an open MCM ring for helicase loading

PubMed Central

Frigola, Jordi; He, Jun; Kinkelin, Kerstin; Pye, Valerie E.; Renault, Ludovic; Douglas, Max E.; Remus, Dirk; Cherepanov, Peter; Costa, Alessandro; Diffley, John F. X.

2017-01-01

ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2–5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2–5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC–Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure. PMID:28643783

Chaperone-assisted protein aggregate reactivation: Different solutions for the same problem.

PubMed

Aguado, Alejandra; Fernández-Higuero, José Angel; Moro, Fernando; Muga, Arturo

2015-08-15

The oligomeric AAA+ chaperones Hsp104 in yeast and ClpB in bacteria are responsible for the reactivation of aggregated proteins, an activity essential for cell survival during severe stress. The protein disaggregase activity of these members of the Hsp100 family is linked to the activity of chaperones from the Hsp70 and Hsp40 families. The precise mechanism by which these proteins untangle protein aggregates remains unclear. Strikingly, Hsp100 proteins are not present in metazoans. This does not mean that animal cells do not have a disaggregase activity, but that this activity is performed by the Hsp70 system and a representative of the Hsp110 family instead of a Hsp100 protein. This review describes the actual view of Hsp100-mediated aggregate reactivation, including the ATP-induced conformational changes associated with their disaggregase activity, the dynamics of the oligomeric assembly that is regulated by its ATPase cycle and the DnaK system, and the tight allosteric coupling between the ATPase domains within the hexameric ring complexes. The lack of homologs of these disaggregases in metazoans has suggested that they might be used as potential targets to develop antimicrobials. The current knowledge of the human disaggregase machinery and the role of Hsp110 are also discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Pre-surgical Psychological and Neuroendocrine Predictors of Psychiatric Morbidity Following Major Vascular Surgery: A Prospective Longitudinal Study

PubMed Central

King, Anthony P.; Abelson, James L.; Gholami, Bardia; Upchurch, Gilbert R.; Henke, Peter; Graham, Linda; Liberzon, Israel

2015-01-01

Objective Major life stressors, including major surgeries, are often followed by psychiatric symptoms and disorders. Prior retrospective work found abdominal-aortic aneurysm (AAA) repair is followed by increased psychiatric morbidity, which may adversely influence physical and functional recovery. Identifying risk factors prior to surgery, such as dysregulation in stress response systems, might be useful to improving preventative intervention. Methods Two hundred and sixteen patients receiving open AAA or aortofemoral bypass (AFB) surgeries, endovascular AAA repair (EVAR), or nonsurgical AAA treatment were recruited from two vascular surgery services. Psychiatric symptoms and salivary cortisol measures (waking, 4 pm, and 11 pm, before and after low-dose dexamethasone) were obtained at intake and 3 and 9 month followups. Results Following open surgeries, 18% of patients had new psychiatric disorders, compared to 4% of patients receiving EVAR or nonsurgical treatment (odds ratio = 6.0, 95% CI 1.6 - 22.1, p=.007). Having a history of major depression predicted onset of new disorders in surgical patients. Pre-surgical cortisol levels were associated with both baseline (r=.23, p<.05) and 9 month (r=.32, p<.01) psychiatric symptoms (cortisol B=1.0, SE=0.48, p<.05 in repeated measures mixed model). Conclusion Open AAA repair surgery is prospectively linked to development of psychiatric morbidity, and history of depression elevates risk. Cortisol measures prior to surgery are associated with current and future psychological functioning, suggesting potential neurobiological mechanisms that may contribute to vulnerability. These results can help identify surgical patients at risk, and point to potential targets for risk reduction interventions. PMID:26461854

DOE Office of Scientific and Technical Information (OSTI.GOV)

Codel, G; Serin, E; Pacaci, P

Purpose: In this study, the comparison of dosimetric accuracy of Acuros XB and AAA algorithms were investigated for small radiation fields incident on homogeneous and heterogeneous geometries Methods: Small open fields of Truebeam 2.0 unit (1×1, 2×2, 3×3, 4×4 fields) were used for this study. The fields were incident on homogeneous phantom and in house phantom containing lung, air, and bone inhomogeneities. Using the same film batch, the net OD to dose calibration curve was obtaine dusing Trubeam 2.0 for 6 MV, 6 FFF, 10 MV, 10 FFF, 15 MV energies by delivering 0- 800 cGy. Films were scanned 48more » hours after irradiation using an Epson 1000XL flatbed scanner. The dosimetric accuracy of Acuros XB and AAA algorithms in the presence of the inhomogeneities was compared against EBT3 film dosimetry Results: Open field tests in a homogeneous phantom showed good agreement betweent wo algorithms and measurement. For Acuros XB, minimum gamma analysis passin grates between measured and calculated dose distributions were 99.3% and 98.1% for homogeneousand inhomogeneous fields in thecase of lung and bone respectively. For AAA, minimum gamma analysis passingrates were 99.1% and 96.5% for homogeneous and inhomogeneous fields respectively for all used energies and field sizes.In the case of the air heterogeneity, the differences were larger for both calculations algorithms. Over all, when compared to measurement, theAcuros XB had beter agreement than AAA. Conclusion: The Acuros XB calculation algorithm in the TPS is an improvemen tover theexisting AAA algorithm. Dose discrepancies were observed for in the presence of air inhomogeneities.« less

AAA+ ATPases Reptin and Pontin as potential diagnostic and prognostic biomarkers in salivary gland cancer - a short report.

PubMed

Mikesch, Jan-Henrik; Hartmann, Wolfgang; Angenendt, Linus; Huber, Otmar; Schliemann, Christoph; Arteaga, Maria Francisca; Wardelmann, Eva; Rudack, Claudia; Berdel, Wolfgang E; Stenner, Markus; Grünewald, Inga

2018-06-05

Salivary gland cancer (SGC) is a rare and heterogeneous disease with significant differences in recurrence and metastasis characteristics. As yet, little is known about the mechanisms underlying the initiation and/or progression of these diverse tumors. In recent years, the AAA+ ATPase family members Pontin (RuvBL1, Tip49a) and Reptin (RuvBL2, Tip49b) have been implicated in various processes, including transcription regulation, chromatin remodeling and DNA damage repair, that are frequently deregulated in cancer. The aim of this study was to assess the clinical and functional significance of Reptin and Pontin expression in SGC. Immunohistochemical staining of Pontin, Reptin, β-catenin, Cyclin D1, TP53 and MIB-1 was performed on a collection of 94 SGC tumor samples comprising 13 different histological subtypes using tissue microarrays. We found that Reptin and Pontin were expressed in the majority of SGC samples across all histological subtypes. Patients with a high Reptin expression showed a significantly inferior 5-year overall survival rate compared to patients with a low Reptin expression (47.7% versus 78.3%; p = 0.033), whereas no such difference was observed for Pontin. A high Reptin expression strongly correlated with a high expression of the proliferation marker MIB-1 (p = 0.003), the cell cycle regulator Cyclin D1 (p = 0.006), accumulation of TP53 as a surrogate p53 mutation marker (p = 0.042) and cytoplasmic β-catenin expression (p = 0.002). Increased Pontin expression was found to significantly correlate with both cytoplasmic and nuclear β-catenin expression (p = 0.037 and p = 0.018, respectively), which is indicative for its oncogenic function. Our results suggest a role of Reptin and Pontin in SGC tumor progression and/or patient survival. Therefore, SGC patients exhibiting a high Reptin expression may benefit from more aggressive therapeutic regimens. Future studies should clarify whether such patients may be considered for more radical surgery, extended adjuvant therapy and/or targeted therapy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutter, Markus; Roberts, Evan W.; Gonzalez, Raul C.

Carboxysomes are bacterial microcompartments that enhance carbon fixation by concentrating ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and its substrate CO 2 within a proteinaceous shell. They are found in all cyanobacteria, some purple photoautotrophs and many chemoautotrophic bacteria. Carboxysomes consist of a protein shell that encapsulates several hundred molecules of RuBisCO, and contain carbonic anhydrase and other accessory proteins. Genes coding for carboxysome shell components and the encapsulated proteins are typically found together in an operon. The α-carboxysome operon is embedded in a cluster of additional, conserved genes that are presumably related to its function. In many chemoautotrophs, products of the expanded carboxysomemore » locus include CbbO and CbbQ, a member of the AAA+ domain superfamily. We bioinformatically identified subtypes of CbbQ proteins and show that their genes frequently co-occur with both Form IA and Form II RuBisCO. The α-carboxysome-associated ortholog, CsoCbbQ, from Halothiobacillus neapolitanus forms a hexamer in solution and hydrolyzes ATP. The crystal structure shows that CsoCbbQ is a hexamer of the typical AAA+ domain; the additional C-terminal domain, diagnostic of the CbbQ subfamily, structurally fills the inter-monomer gaps, resulting in a distinctly hexagonal shape. Finally, we show that CsoCbbQ interacts with CsoCbbO and is a component of the carboxysome shell, the first example of ATPase activity associated with a bacterial microcompartment.« less

Smoking, sex, risk factors and abdominal aortic aneurysms: a prospective study of 18 782 persons aged above 65 years in the Southern Community Cohort Study.

PubMed

Jahangir, Eiman; Lipworth, Loren; Edwards, Todd L; Kabagambe, Edmond K; Mumma, Michael T; Mensah, George A; Fazio, Sergio; Blot, William J; Sampson, Uchechukwu K A

2015-05-01

Abdominal aortic aneurysm (AAA) is a leading cause of death in the USA. We evaluated the incidence and predictors of AAA in a prospectively followed cohort. We calculated age-adjusted AAA incidence rates (IR) among 18 782 participants aged ≥65 years in the Southern Community Cohort Study who received Medicare coverage from 1999-2012, and assessed predictors of AAA using multivariable Cox proportional hazards models, overall and stratified by sex, adjusting for demographic, lifestyle, socioeconomic, medical and other factors. HRs and 95% CIs were calculated for AAA in relation to factors ascertained at enrolment. Over a median follow-up of 4.94 years, 281 cases were identified. Annual IR was 153/100,000, 401, 354 and 174 among blacks, whites, men and women, respectively. AAA risk was lower among women (HR 0.48, 95% CI 0.36 to 0.65) and blacks (HR 0.51, 95% CI 0.37 to 0.69). Smoking was the strongest risk factor (former: HR 1.91, 95% CI 1.27 to 2.87; current: HR 5.55, 95% CI 3.67 to 8.40), and pronounced in women (former: HR 3.4, 95% CI 1.83 to 6.31; current: HR 9.17, 95% CI 4.95 to 17). A history of hypertension (HR 1.44, 95% CI 1.04 to 2.01) and myocardial infarction or coronary artery bypass surgery (HR 1.9, 95% CI 1.37 to 2.63) was negatively associated, whereas a body mass index ≥25 kg/m(2) (HR 0.72; 95% CI 0.53 to 0.98) was protective. College education (HR 0.6, 95% CI 0.37 to 0.97) and black race (HR 0.44, 95% CI 0.28 to 0.67) were protective among men. Smoking is a major risk factor for incident AAA, with a strong and similar association between men and women. Further studies are needed to evaluate benefits of ultrasound screening for AAA among women smokers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

One-year outcomes after ruptured abdominal aortic aneurysms repair: is evar the best choice? A single-center experience.

PubMed

Martinelli, O; Fenelli, C; Ben-Hamida, J; Fresilli, M; Irace, F G; Picone, V; Malaj, A; Gossetti, B; Irace, L

2018-06-06

Treatment of ruptured abdominal aortic aneurysms (rAAAs) is still burdened by high morbidity and mortality. Although endovascular aortic repair (EVAR) offers encouraging results in elective setting, its role as first line strategy to treat rAAA is still debated. Our aim was to compare early and late outcomes in patients undergoing open surgical repair (OSR) compared with those submitted to vs EVAR for rAAAs. A retrospective review of data extracted from medical records identified 105 consecutive patients with rAAA who were submitted to open or endovascular repairs from 2008 to 2016. Primary endpoint was to assess the rAAA-related mortality in the immediate postoperative, within 1 month and 1 year after ORS and EVAR Secondary endpoints included: length of stay, AAA-related postoperative complications such as acute limb ischemia, myocardial infarction, renal and respiratory failure and rAAA-related re-interventions. Statistical analysis was performed using the Fisher exact test,χ2 test and logistic regression calculations. Early and midterm survival rates were assessed with Cox model. Of the 105 patients with rAAA 70.48% underwent OSR including 41.89% which was hemodynamically (Hd) unstable and the remaining 29.52% was submitted to rEVAR. (all Hd stable). Compared EVAR group, the OSR group had a higher RAAA-related mortality rate for both Hd stable and Hd unstable patients: 18.92% vs 6.45% at 24 hours; (P = .185) 39.19% vs 19.35% at 30 days (P = .082); 44.59% vs 38.71% at 1 year (P = .734) If only Hd stable patients were considered, mortality following OSR and EVAR was: 6.98% vs 6.45% at 24 hours (P = .703); 27.91% vs 19.35% at 30 days (P = .567); 32.56% vs 38.71% at 1 year (P = .764). Mean length of stay for patients was 15 days after OSR and 10 days after rEVAR (P = .002). At 1-year follow-up, the overall rAAA-related complications incidence was higher in the rEVAR group than in the OSR group (47.85% vs 18.33%; P = .008); re-interventions were 18.33% in OSR group vs 21.82% in EVAR group (P = .917). Cox model showed that instability and coronary artery disease were predictors of overall mortality of rAAAs. EVAR does not independently reduce 1-year mortality in comparison with OSR in Hd-stable patients. Urgent EVAR for rAAAs in unstable patients can be limited by logistical problems. It follows that patients selected for OSR have a more complex aortic anatomy and worse Hd status than those sumitted to rEVAR. rEVAR burdened by a higher incidence of procedure-related complications than OSR. Reconfiguration of acute aortic services and establishment of standardized institutional protocols might be advisable for improvements in the management of ruptured AAA. A carefully evaluation of whether the benefits of an endovascular strategy translate into longer term benefit is needed before definitive conclusions can be drawn about the advantages of EVAR as first-line strategy for ruptured aneurysms. Copyright © 2018 Elsevier Inc. All rights reserved.

Risk profiles for aortic dissection and ruptured or surgically treated aneurysms: a prospective cohort study.

PubMed

Landenhed, Maya; Engström, Gunnar; Gottsäter, Anders; Caulfield, Michael P; Hedblad, Bo; Newton-Cheh, Christopher; Melander, Olle; Smith, J Gustav

2015-01-21

Community screening to guide preventive interventions for acute aortic disease has been recommended in high-risk individuals. We sought to prospectively assess risk factors in the general population for aortic dissection (AD) and severe aneurysmal disease in the thoracic and abdominal aorta. We studied the incidence of AD and ruptured or surgically treated aneurysms in the abdominal (AAA) or thoracic aorta (TAA) in 30 412 individuals without diagnosis of aortic disease at baseline from a contemporary, prospective cohort of middle-aged individuals, the Malmö Diet and Cancer study. During up to 20 years of follow-up (median 16 years), the incidence rate per 100 000 patient-years at risk was 15 (95% CI 11.7 to 18.9) for AD, 27 (95% CI 22.5 to 32.1) for AAA, and 9 (95% CI 6.8 to 12.6) for TAA. The acute and in-hospital mortality was 39% for AD, 34% for ruptured AAA, and 41% for ruptured TAA. Hypertension was present in 86% of individuals who subsequently developed AD, was strongly associated with incident AD (hazard ratio [HR] 2.64, 95% CI 1.33 to 5.25), and conferred a population-attributable risk of 54%. Hypertension was also a risk factor for AAA with a smaller effect. Smoking (HR 5.07, 95% CI 3.52 to 7.29) and high apolipoprotein B/A1 ratio (HR 2.48, 95% CI 1.73 to 3.54) were strongly associated with AAA and conferred a population-attributable risk of 47% and 25%, respectively. Smoking was also a risk factor for AD and TAA with smaller effects. This large prospective study identified distinct risk factor profiles for different aortic diseases in the general population. Hypertension accounted for more than half of the population risk for AD, and smoking for half of the population risk of AAA. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

High-intensity interval exercise training before abdominal aortic aneurysm repair (HIT-AAA): protocol for a randomised controlled feasibility trial.

PubMed

Tew, Garry A; Weston, Matthew; Kothmann, Elke; Batterham, Alan M; Gray, Joanne; Kerr, Karen; Martin, Denis; Nawaz, Shah; Yates, David; Danjoux, Gerard

2014-01-10

In patients with large abdominal aortic aneurysm (AAA), open surgical or endovascular aneurysm repair procedures are often used to minimise the risk of aneurysm-related rupture and death; however, aneurysm repair itself carries a high risk. Low cardiopulmonary fitness is associated with an increased risk of early post-operative complications and death following elective AAA repair. Therefore, fitness should be enhanced before aneurysm repair. High-intensity interval exercise training (HIT) is a potent, time-efficient strategy for enhancing cardiopulmonary fitness. Here, we describe a feasibility study for a definitive trial of a pre-operative HIT intervention to improve post-operative outcomes in patients undergoing elective AAA repair. A minimum of 50 patients awaiting elective repair of a 5.5-7.0 cm infrarenal AAA will be allocated by minimisation to HIT or usual care control in a 1:1 ratio. The patients allocated to HIT will complete three hospital-based exercise sessions per week, for 4 weeks. Each session will include 2 or 4 min of high-intensity stationary cycling followed by the same duration of easy cycling or passive recovery, repeated until a total of 16 min of high-intensity exercise is accumulated. Outcomes to be assessed before randomisation and 24-48 h before aneurysm repair include cardiopulmonary fitness, maximum AAA diameter and health-related quality of life. In the post-operative period, we will record destination (ward or critical care unit), organ-specific morbidity, mortality and the durations of critical care and hospital stay. Twelve weeks after the discharge, participants will be interviewed to reassess quality of life and determine post-discharge healthcare utilisation. The costs associated with the exercise intervention and healthcare utilisation will be calculated. Ethics approval was secured through Sunderland Research Ethics Committee. The findings of the trial will be disseminated through peer-reviewed journals, and national and international presentations. Current Controlled Trials ISRCTN09433624.

Isolation, purification, and partial characterization of a membrane-bound Cl-/HCO3--activated ATPase complex from rat brain with sensitivity to GABAAergic ligands.

PubMed

Menzikov, Sergey A

2017-02-07

This study describes the isolation and purification of a protein complex with [Formula: see text]-ATPase activity and sensitivity to GABA A ergic ligands from rat brain plasma membranes. The ATPase complex was enriched using size-exclusion, affinity, and ion-exchange chromatography. The fractions obtained at each purification step were subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE), which revealed four subunits with molecular mass ∼48, 52, 56, and 59 kDa; these were retained at all stages of the purification process. Autoradiography revealed that the ∼52 and 56 kDa subunits could bind [ 3 H]muscimol. The [Formula: see text]-ATPase activity of this enriched protein complex was regulated by GABA A ergic ligands but was not sensitive to blockers of the NKCC or KCC cotransporters.

Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase, Na +/K+/2Cl- cotransporter and CFTR anion channel

USGS Publications Warehouse

Hiroi, J.; McCormick, S.D.; Ohtani-Kaneko, R.; Kaneko, T.

2005-01-01

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins, Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K +-ATPase staining; type II, basolateral Na+/K +-ATPase and apical NKCC; type III, basolateral Na+/K +-ATPase and basolateral NKCC; type IV, basolateral Na +/K+-ATPase, basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.

Molecular architecture of the 26S proteasome holocomplex determined by an integrative approach

PubMed Central

Lasker, Keren; Förster, Friedrich; Bohn, Stefan; Walzthoeni, Thomas; Villa, Elizabeth; Unverdorben, Pia; Beck, Florian; Aebersold, Ruedi; Sali, Andrej; Baumeister, Wolfgang

2012-01-01

The 26S proteasome is at the executive end of the ubiquitin-proteasome pathway for the controlled degradation of intracellular proteins. While the structure of its 20S core particle (CP) has been determined by X-ray crystallography, the structure of the 19S regulatory particle (RP), which recruits substrates, unfolds them, and translocates them to the CP for degradation, has remained elusive. Here, we describe the molecular architecture of the 26S holocomplex determined by an integrative approach based on data from cryoelectron microscopy, X-ray crystallography, residue-specific chemical cross-linking, and several proteomics techniques. The “lid” of the RP (consisting of Rpn3/5/6/7/8/9/11/12) is organized in a modular fashion. Rpn3/5/6/7/9/12 form a horseshoe-shaped heterohexamer, which connects to the CP and roofs the AAA-ATPase module, positioning the Rpn8/Rpn11 heterodimer close to its mouth. Rpn2 is rigid, supporting the lid, while Rpn1 is conformationally variable, positioned at the periphery of the ATPase ring. The ubiquitin receptors Rpn10 and Rpn13 are located in the distal part of the RP, indicating that they were recruited to the complex late in its evolution. The modular structure of the 26S proteasome provides insights into the sequence of events prior to the degradation of ubiquitylated substrates. PMID:22307589

Chronic Kidney Disease Is Positively and Diabetes Mellitus Is Negatively Associated with Abdominal Aortic Aneurysm

PubMed Central

Uchida, Haruhito A.; Kakio, Yuki; Umebayashi, Ryoko; Okuyama, Yuka; Fujii, Yasuhiro; Ozawa, Susumu; Yoshida, Masashi; Oshima, Yu; Sano, Shunji; Wada, Jun

2016-01-01

Background and Aims Chronic kidney disease (CKD) and diabetes mellitus (DM) are considered as risk factors for cardiovascular diseases. The purpose of this study was to clarify the relationship of CKD and DM with the presence of abdominal aortic aneurysm (AAA). Methods We enrolled 261 patients with AAA (AAA+) and age-and-sex matched 261 patients without AAA (AAA-) at two hospitals between 2008 and 2014, and examined the association between the risk factors and the presence of AAA. Furthermore, in order to investigate the prevalence of AAA in each group, we enrolled 1126 patients with CKD and 400 patients with DM. Results The presence of CKD in patients with AAA+ was significantly higher than that in patients with AAA- (AAA+; 65%, AAA-; 52%, P = 0.004). The presence of DM in patients with AAA+ was significantly lower than that in patients with AAA- (AAA+; 17%, AAA-; 35%, P < 0.001). A multivariate logistic regression analysis demonstrated that hypertension, ischemic heart disease and CKD were independent determinants, whereas, DM was a negatively independent determinant, for the presence of AAA. The prevalence of AAA in patients with CKD 65 years old and above was 5.1%, whereas, that in patients with DM 65 years old and above was only 0.6%. Conclusion CKD is a positively associated with the presence of AAA. In contrast, DM is a negatively associated with the presence of AAA in Japanese population. PMID:27764090

A NASTRAN Vibration Model of the AH-1G Helicopter Airframe. Volume 1

DTIC Science & Technology

1974-06-01

Bulkhead .012 ZZ 1863343 Bulkhead .012 AAA 1863345 Bulkhead .012 j EBB 1863546 Bulkhead .012 j ccc 1863746 Bulkhead .012 \\ ODD 1863748...123 12) 123 RULE AAA AAA AAA AAA BBB EBB AAA AAA AAA AAA BBB BBB OMIT D.O.F. 456 456 123 123 123 123 123 123 123 123 RULE...load in the member Increases. The program determines the section properties, unsytnmetrical bending stresses, element loads and shear flows for a

Glucose-independent inhibition of yeast plasma-membrane H+-ATPase by calmodulin antagonists.

PubMed

Romero, I; Maldonado, A M; Eraso, P

1997-03-15

Glucose metabolism causes activation of the yeast plasma-membrane H+-ATPase. The molecular mechanism of this regulation is not known, but it is probably mediated by phosphorylation of the enzyme. The involvement in this process of several kinases has been suggested but their actual role has not been proved. The physiological role of a calmodulin-dependent protein kinase in glucose-induced activation was investigated by studying the effect of specific calmodulin antagonists on the glucose-induced ATPase kinetic changes in wild-type and two mutant strains affected in the glucose regulation of the enzyme. Preincubation of the cells with calmidazolium or compound 48/80 impeded the increase in ATPase activity by reducing the Vmax of the enzyme without modifying the apparent affinity for ATP in the three strains. In one mutant, pma1-T912A, the putative calmodulin-dependent protein kinase-phosphorylatable Thr-912 was eliminated, and in the other, pma1-P536L, H+-ATPase was constitutively activated, suggesting that the antagonistic effect was not mediated by a calmodulin-dependent protein kinase and not related to glucose regulation. This was corroborated when the in vitro effect of the calmodulin antagonists on H+-ATPase activity was tested. Purified plasma membranes from glucose-starved or glucose-fermenting cells from both pma1-P890X, another constitutively activated ATPase mutant, and wild-type strains were preincubated with calmidazolium or melittin. In all cases, ATP hydrolysis was inhibited with an IC50 of approximately 1 microM. This inhibition was reversed by calmodulin. Analysis of the calmodulin-binding protein pattern in the plasma-membrane fraction eliminates ATPase as the calmodulin target protein. We conclude that H+-ATPase inhibition by calmodulin antagonists is mediated by an as yet unidentified calmodulin-dependent membrane protein.

Long-term outcomes after repair of symptomatic abdominal aortic aneurysms.

PubMed

Chandra, Venita; Trang, Karen; Virgin-Downey, Whitt; Dalman, Ronald L; Mell, Matthew W

2018-04-25

Previous studies have reported increased perioperative mortality of nonruptured symptomatic abdominal aortic aneurysms (Sx-AAA) compared with asymptomatic elective AAA (E-AAA) repairs, but no long-term-outcomes have been reported. We sought to compare long-term outcomes of Sx-AAA and E-AAA after repair at a single academic institution. Patients receiving AAA repair for Sx-AAA and E-AAA from 1995 through 2015 were included. Ruptured AAA and suprarenal or thoracoabdominal AAA were excluded. Demographics, comorbidities, and operative approach were collected. Long-term mortality was the primary outcome, determined by chart review or link to Social Security Death Index. Additionally, long-term mortality and reinterventions were compared after groups were matched with nearest neighbor propensity to reduce bias. AAA repair was performed for 1054 E-AAA (383 open repair [36%], 671 endovascular aneurysm repair [EVAR] [64%]), and 139 symptomatic aneurysms (60 open repair [43%], 79 EVAR [57%]). Age (73 years vs 74 years; P = .13) and aneurysm diameter were similar between Sx-AAA and E-AAA (6.0 cm vs 5.8 cm; P = .5). The proportion of women was higher for Sx-AAA (26% vs 16%; P = .003), as was the proportion of non-Caucasians (40% vs 29%; P = .009). After propensity matching, there were no differences between groups for patient characteristics, AAA diameter, treatment modality, or comorbidities, including hypertension, coronary artery disease, congestive heart failure, diabetes, hyperlipidemia, lung disease, diabetes, renal disease, and smoking history. Women were treated for Sx-AAA at significantly smaller aortic diameters; however, compared with men (5.1 cm vs 6.3 cm; P < .001). Perioperative mortality was 5.0% for Sx-AAA and 2.3% for E-AAA (P = .055). By life-table analysis, Sx-AAA had lower 5-year (62% vs 71%) and 10-year (39% vs 51%) survivals (P = .01) compared with E-AAA for the entire cohort. Similar trends were observed for 5-year and 10-year mortality after propensity matching (63% and 40% vs 71% and 52%; P = .05). When stratified by repair type 5-year and 10-year survivals trended lower after open surgery (68% and 42% Sx-AAA vs 84% and 59% E-AAA; P = .08) but not EVAR (59% and 40% Sx-AAA vs 61% and 49% E-AAA; P = .4). Aneurysm-related reinterventions were similar for Sx-AAA and E-AAA (15% vs 14%; P = .8). Reinterventions were more common after EVAR compared with open repair (22% vs 7%, Sx-AAA P = .015; 20% vs 4% E-AAA; P = .007). Patients with Sx-AAA had lower long-term survival and similar aneurysm-related reinterventions compared with patients with E-AAA undergoing repair. Women also underwent repair for Sx-AAA at a significantly smaller size when compared with men, which emphasizes the role of gender in AAA symptomatology. Differences in long-term survival may be only partially explained by measured patient, aneurysm, and operative factors, and may reflect unmeasured social factors or suggest inherent differences in pathophysiology of Sx-AAAs. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Readout Electronics for the Central Drift Chamber of the Belle-II Detector

NASA Astrophysics Data System (ADS)

Uchida, Tomohisa; Taniguchi, Takashi; Ikeno, Masahiro; Iwasaki, Yoshihito; Saito, Masatoshi; Shimazaki, Shoichi; Tanaka, Manobu M.; Taniguchi, Nanae; Uno, Shoji

2015-08-01

We have developed readout electronics for the central drift chamber (CDC) of the Belle-II detector. The space near the endplate of the CDC for installation of the electronics was limited by the detector structure. Due to the large amounts of data generated by the CDC, a high-speed data link, with a greater than one gigabit transfer rate, was required to transfer the data to a back-end computer. A new readout module was required to satisfy these requirements. This module processes 48 signals from the CDC, converts them to digital data and transfers it directly to the computer. All functions that transfer digital data via the high speed link were implemented on the single module. We have measured its electrical characteristics and confirmed that the results satisfy the requirements of the Belle-II experiment.

N-terminal lysines are essential for protein translocation via a modified ERAD system in complex plastids.

PubMed

Lau, Julia B; Stork, Simone; Moog, Daniel; Sommer, Maik S; Maier, Uwe G

2015-05-01

Nuclear-encoded pre-proteins being imported into complex plastids of red algal origin have to cross up to five membranes. Thereby, transport across the second outermost or periplastidal membrane (PPM) is facilitated by SELMA (symbiont-specific ERAD-like machinery), an endoplasmic reticulum-associated degradation (ERAD)-derived machinery. Core components of SELMA are enzymes involved in ubiquitination (E1-E3), a Cdc48 ATPase complex and Derlin proteins. These components are present in all investigated organisms with four membrane-bound complex plastids of red algal origin, suggesting a ubiquitin-dependent translocation process of substrates mechanistically similar to the process of retro-translocation in ERAD. Even if, according to the current model, translocation via SELMA does not end up in the classical poly-ubiquitination, transient mono-/oligo-ubiquitination of pre-proteins might be required for the mechanism of translocation. We investigated the import mechanism of SELMA and were able to show that protein transport across the PPM depends on lysines in the N-terminal but not in the C-terminal part of pre-proteins. These lysines are predicted to be targets of ubiquitination during the translocation process. As proteins lacking the N-terminal lysines get stuck in the PPM, a 'frozen intermediate' of the translocation process could be envisioned and initially characterized. © 2015 John Wiley & Sons Ltd.

Family Members of Patients with Abdominal Aortic Aneurysms are at Increased Risk for Aneurysms: Analysis of 618 Probands and their Families from the Liège AAA Family Study

PubMed Central

Sakalihasan, Natzi; Defraigne, Jean-Olivier; Kerstenne, Marie-Ange; Cheramy-Bien, Jean-Paul; Smelser, Diane T.; Tromp, Gerard; Kuivaniemi, Helena

2014-01-01

Background The objectives were to answer the following questions using a well-characterized population in Liège, Belgium: 1) what percentage of abdominal aortic aneurysm (AAA) patients have a positive family history for AAA, 2) what is the prevalence of AAAs among relatives of AAA patients; and 3) do familial and sporadic AAA cases differ in clinical characteristics. Methods and Results Unrelated AAA patients diagnosed at the Cardiovascular Surgery Department, University Hospital of Liège, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. In the initial interview 62 (10%) of the 618 AAA patients reported a positive family history for AAA. We divided the 618 patients into two study groups: Group I: 296 AAA patients (268; 91% males) were followed up with computerized tomography combined with positron emission tomography, and Group II: 322 AAA patients (295; 92% males) whose families were invited to ultrasonography screening. Ultrasonography screening identified 24 new AAAs among 186 relatives (≥ 50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonography screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P<0.0001). Conclusions The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis and provide rationale for targeted screening of relatives of AAA patients. PMID:24365082

Family members of patients with abdominal aortic aneurysms are at increased risk for aneurysms: analysis of 618 probands and their families from the Liège AAA Family Study.

PubMed

Sakalihasan, Natzi; Defraigne, Jean-Olivier; Kerstenne, Marie-Ange; Cheramy-Bien, Jean-Paul; Smelser, Diane T; Tromp, Gerard; Kuivaniemi, Helena

2014-05-01

The objectives were to answer the following questions with the help of a well-characterized population in Liège, Belgium: 1) what percentage of patients with abdominal aortic aneurysm (AAA) have a positive family history for AAA? 2) what is the prevalence of AAAs among relatives of patients with AAA? and 3) do familial and sporadic AAA cases differ in clinical characteristics? Patients with unrelated AAA diagnosed at the Cardiovascular Surgery Department, University Hospital of Liège, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. We divided the 618 patients into 2 study groups: group I, 296 patients with AAA (268; 91% men) were followed up with computerized tomography combined with positron emission tomography; and group II, 322 patients with AAA (295; 92% men) whose families were invited to ultrasonographic screening. In the initial interview, 62 (10%) of the 618 patients with AAA reported a positive family history for AAA. Ultrasonographic screening identified 24 new AAAs among 186 relatives (≥50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonographic screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P < 0.0001). The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis, and provide rationale for targeted screening of relatives of patients with AAA. Copyright © 2014 Elsevier Inc. All rights reserved.

Mak5 and Ebp2 Act Together on Early Pre-60S Particles and Their Reduced Functionality Bypasses the Requirement for the Essential Pre-60S Factor Nsa1

PubMed Central

Pratte, Dagmar; Singh, Ujjwala; Murat, Guillaume; Kressler, Dieter

2013-01-01

Ribosomes are the molecular machines that translate mRNAs into proteins. The synthesis of ribosomes is therefore a fundamental cellular process and consists in the ordered assembly of 79 ribosomal proteins (r-proteins) and four ribosomal RNAs (rRNAs) into a small 40S and a large 60S ribosomal subunit that form the translating 80S ribosomes. Most of our knowledge concerning this dynamic multi-step process comes from studies with the yeast Saccharomyces cerevisiae, which have shown that assembly and maturation of pre-ribosomal particles, as they travel from the nucleolus to the cytoplasm, relies on a multitude (>200) of biogenesis factors. Amongst these are many energy-consuming enzymes, including 19 ATP-dependent RNA helicases and three AAA-ATPases. We have previously shown that the AAA-ATPase Rix7 promotes the release of the essential biogenesis factor Nsa1 from late nucleolar pre-60S particles. Here we show that mutant alleles of genes encoding the DEAD-box RNA helicase Mak5, the C/D-box snoRNP component Nop1 and the rRNA-binding protein Nop4 bypass the requirement for Nsa1. Interestingly, dominant-negative alleles of RIX7 retain their phenotype in the absence of Nsa1, suggesting that Rix7 may have additional nuclear substrates besides Nsa1. Mak5 is associated with the Nsa1 pre-60S particle and synthetic lethal screens with mak5 alleles identified the r-protein Rpl14 and the 60S biogenesis factors Ebp2, Nop16 and Rpf1, which are genetically linked amongst each other. We propose that these ’Mak5 cluster’ factors orchestrate the structural arrangement of a eukaryote-specific 60S subunit surface composed of Rpl6, Rpl14 and Rpl16 and rRNA expansion segments ES7L and ES39L. Finally, over-expression of Rix7 negatively affects growth of mak5 and ebp2 mutant cells both in the absence and presence of Nsa1, suggesting that Rix7, at least when excessively abundant, may act on structurally defective pre-60S subunits and may subject these to degradation. PMID:24312670

Aortic outflow occlusion predicts rupture of abdominal aortic aneurysm.

PubMed

Crawford, Jeffrey D; Chivukula, Venkat Keshav; Haller, Stephen; Vatankhah, Nasibeh; Bohannan, Colin J; Moneta, Gregory L; Rugonyi, Sandra; Azarbal, Amir F

2016-12-01

Current threshold recommendations for elective abdominal aortic aneurysm (AAA) repair are based solely on maximal AAA diameter. Peak wall stress (PWS) has been demonstrated to be a better predictor than AAA diameter of AAA rupture risk. However, PWS calculations are time-intensive, not widely available, and therefore not yet clinically practical. In addition, PWS analysis does not account for variations in wall strength between patients. We therefore sought to identify surrogate clinical markers of increased PWS and decreased aortic wall strength to better predict AAA rupture risk. Patients treated at our institution from 2001 to 2014 for ruptured AAA (rAAA) were retrospectively identified and grouped into patients with small rAAA (maximum diameter <6 cm) or large rAAA (>6 cm). Patients with large (>6 cm) non-rAAA were also identified sequentially from 2009 for comparison. Demographics, vascular risk factors, maximal aortic diameter, and aortic outflow occlusion (AOO) were recorded. AOO was defined as complete occlusion of the common, internal, or external iliac artery. Computational fluid dynamics and finite element analysis simulations were performed to calculate wall stress distributions and to extract PWS. We identified 61 patients with rAAA, of which 15 ruptured with AAA diameter <60 mm (small rAAA group). Patients with small rAAAs were more likely to have peripheral arterial disease (PAD) and chronic obstructive pulmonary disease (COPD) than were patients in the large non-rAAA group. Patients with small rAAAs were also more likely to have AOO compared with non-rAAAs >60 mm (27% vs 8%; P = .047). Among all patients with rAAAs, those with AOO ruptured at smaller mean AAA diameters than in patients without AOO (62.1 ± 11.8 mm vs 72.5 ± 16.4 mm; P = .024). PWS calculations of a representative small rAAA and a large non-rAAA showed a substantial increase in PWS with AOO. We demonstrate that AOO, PAD, and COPD in AAA are associated with rAAAs at smaller diameters. AOO appears to increase PWS, whereas COPD and PAD may be surrogate markers of decreased aortic wall strength. We therefore recommend consideration of early, elective AAA repair in patients with AOO, PAD, or COPD to minimize risk of early rupture. Copyright © 2016. Published by Elsevier Inc.

75 FR 39694 - Agency Information Collection Request. 60-Day Public Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-12

... Topic and community Guide). members. Guide for Discussion with Control group 48 1 1 48 Control Group... and Evaluation (ASPE), the Centers for Disease Control and Prevention (CDC), and the Administration... the treatment-control contrast evaluated in each site. It will also help in interpreting impact...

Online Reports of Foodborne Illness Capture Foods Implicated in Official Foodborne Outbreak Reports

PubMed Central

Nsoesie, Elaine O.; Gordon, Sheryl A.; Brownstein, John S.

2014-01-01

Objective Traditional surveillance systems only capture a fraction of the estimated 48 million yearly cases of foodborne illness in the United States. We assessed whether foodservice reviews on Yelp.com (a business review site) can be used to support foodborne illness surveillance efforts. Methods We obtained reviews from 2005–2012 of 5824 foodservice businesses closest to 29 colleges. After extracting recent reviews describing episodes of foodborne illness, we compared implicated foods to foods in outbreak reports from the U.S. Centers for Disease Control and Prevention (CDC). Results Broadly, the distribution of implicated foods across five categories was as follows: aquatic (16% Yelp, 12% CDC), dairy-eggs (23% Yelp, 23% CDC), fruits-nuts (7% Yelp, 7% CDC), meat-poultry (32% Yelp, 33% CDC), and vegetables (22% Yelp, 25% CDC). The distribution of foods across 19 more specific food categories was also similar, with spearman correlations ranging from 0.60 to 0.85 for 2006–2011. The most implicated food categories in both Yelp and CDC were beef, dairy, grains-beans, poultry and vine-stalk. Conclusions Based on observations in this study and the increased usage of social media, we posit that online illness reports could complement traditional surveillance systems by providing near real-time information on foodborne illnesses, implicated foods and locations. PMID:25124281

Endogenous acetylcholine increases alveolar epithelial fluid transport via activation of alveolar epithelial Na,K-ATPase in mice.

PubMed

Li, Xia; Yan, Xi Xin; Li, Hong Lin; Li, Rong Qin

2015-10-01

The contribution of endogenous acetylcholine to alveolar fluid clearance (AFC) and related molecular mechanisms were explored. AFC was measured in Balb/c mice after vagotomy and vagus nerve stimulation. Effects of acetylcholine chloride on AFC in Kunming mice and Na,K-ATPase function in A549 alveolar epithelial cells also were determined. AFC significantly decreased in mice with left cervical vagus nerve transection compared with controls (48.69 ± 2.57 vs. 66.88 ± 2.64, P ≤ 0.01), which was reversed by stimulation of the peripheral (60.81 ± 1.96, P ≤ 0.01). Compared with control, acetylcholine chloride dose-dependently increased AFC and elevated Na,K-ATPase activity, and these increases were blocked or reversed by atropine. These effects were accompanied by recruitment of Na,K-ATPase α1 to the cell membrane. Thus, vagus nerves participate in alveolar epithelial fluid transport by releasing endogenous acetylcholine in the infusion-induced pulmonary edema mouse model. Effects of endogenous acetylcholine on AFC are likely mediated by Na,K-ATPase function through activation of muscarinic acetylcholine receptors on alveolar epithelia. Copyright © 2015 Elsevier B.V. All rights reserved.

Aortic iron overload with oxidative stress and inflammation in human and murine abdominal aortic aneurysm.

PubMed

Sawada, Hisashi; Hao, Hiroyuki; Naito, Yoshiro; Oboshi, Makiko; Hirotani, Shinichi; Mitsuno, Masataka; Miyamoto, Yuji; Hirota, Seiichi; Masuyama, Tohru

2015-06-01

Although iron is an essential element for maintaining physiological function, excess iron leads to tissue damage caused by oxidative stress and inflammation. Oxidative stress and inflammation play critical roles for the development of abdominal aortic aneurysm (AAA). However, it has not been investigated whether iron plays a role in AAA formation through oxidative stress and inflammation. We, therefore, examined whether iron is involved in the pathophysiology of AAA formation using human AAA walls and murine AAA models. Human aortic walls were collected from 53 patients who underwent cardiovascular surgery (non-AAA=34; AAA=19). Murine AAA was induced by infusion of angiotensin II to apolipoprotein E knockout mice. Iron was accumulated in human and murine AAA walls compared with non-AAA walls. Immunohistochemistry showed that both 8-hydroxy-2'-deoxyguanosine and CD68-positive areas were increased in AAA walls compared with non-AAA walls. The extent of iron accumulated area positively correlated with that of 8-hydroxy-2'-deoxyguanosine expression area and macrophage infiltration area in human and murine AAA walls. We next investigated the effects of dietary iron restriction on AAA formation in mice. Iron restriction reduced the incidence of AAA formation with attenuation of oxidative stress and inflammation. Aortic expression of transferrin receptor 1, intracellular iron transport protein, was increased in human and murine AAA walls, and transferrin receptor 1-positive area was similar to areas where iron accumulated and F4/80 were positive. Iron is involved in the pathophysiology of AAA formation with oxidative stress and inflammation. Dietary iron restriction could be a new therapeutic strategy for AAA progression. © 2015 American Heart Association, Inc.

Abdominal Aortic Aneurysm: Evolving Controversies and Uncertainties.

PubMed

Carino, Davide; Sarac, Timur P; Ziganshin, Bulat A; Elefteriades, John A

2018-06-01

Abdominal aortic aneurysm (AAA) is defined as a permanent dilatation of the abdominal aorta that exceeds 3 cm. Most AAAs arise in the portion of abdominal aorta distal to the renal arteries and are defined as infrarenal. Most AAAs are totally asymptomatic until catastrophic rupture. The strongest predictor of AAA rupture is the diameter. Surgery is indicated to prevent rupture when the risk of rupture exceeds the risk of surgery. In this review, we aim to analyze this disease comprehensively, starting from an epidemiological perspective, exploring etiology and pathophysiology, and concluding with surgical controversies. We will pursue these goals by addressing eight specific questions regarding AAA: (1) Is the incidence of AAA increasing? (2) Are ultrasound screening programs for AAA effective? (3) What causes AAA: Genes versus environment? (4) Animal models: Are they really relevant? (5) What pathophysiology leads to AAA? (6) Indications for AAA surgery: Are surgeons over-eager to operate? (7) Elective AAA repair: Open or endovascular? (8) Emergency AAA repair: Open or endovascular?

Rabbit aortic aneurysm model with enlarging diameter capable of better mimicking human aortic aneurysm disease.

PubMed

Bi, Yonghua; Chen, Hongmei; Li, Yahua; Yu, Zepeng; Han, Xinwei; Ren, Jianzhuang

2018-01-01

The self-healing phenomenon can be found in the elastase-induced abdominal aortic aneurysm (AAA) model, and an enlarging AAA model was successfully induced by coarctation. Unfortunately, aortic coarctation in these enlarging models is generally not found in human AAA disease. This study aimed to create an experiment model of enlarging AAA in rabbits to better mimic human aortic aneurysm disease. Eighty-four male New Zealand white rabbits were randomly divided into three equal groups: two aneurysm groups (A and B) and a SHAM group. Aneurysm group rabbits underwent extrinsic aortic stenosis below the right renal artery and received a 10-minute incubation of 60 μl elastase (1 unit/μl). Absorbable suture was used in Group A and nonabsorbable cotton thread was used in Group B. A sham operation was performed in the SHAM group. Aortic diameter was measured after 1, 3, 7, and 15 weeks; thereafter animals were sacrificed for histopathological, immunohistochemical and quantitative studies. Two rabbits died at 29 and 48 days, respectively, after operation in Group B. All aneurysms formed and enlarged progressively by 3 weeks in the Aneurysm groups. However, diameter enlargement in Group A was significantly lower than that in Group B at 7 weeks. Aneurysm groups developed intimal hyperplasia; intima-media thickness (IMT) increased significantly by week 7, and aortic media thickness and intima-media ratio (IMR) increased significantly by week 15. Marked destruction of elastin fibers and smooth muscle cells (SMCs) occurred 1 week later and increased progressively thereafter. Intimal hyperplasia and SMCs content in Group A increased significantly by week 15 compared with Group B. Aneurysm groups exhibited strong expression of matrix metalloproteinases 2 and 9 and RAM11 by week 1, and decreased progressively thereafter. In conclusion, this novel rabbit AAA model enlarges progressively without coarctation and is capable of better mimicking human aortic aneurysm disease.

Experiences of disability consumer-directed care users in Australia: results from a longitudinal qualitative study.

PubMed

Ottmann, Goetz; Laragy, Carmel; Haddon, Michelle

2009-09-01

The rapidly growing body of literature suggests that Consumer-directed Care (CDC) has the potential to empower consumers and improve the flexibility and quality of care. However, reports highlighting quality and risk concerns associated with CDC focusing on a longer time frame have been few. This paper presents the findings from a qualitative longitudinal evaluation of an Australian CDC programme. Focusing on the period between 2003 and 2008, it reports on the experiences of 12 families caring for a dependent family member. It is based on two external evaluations completed 6 and 36 months after enrollment, and one internal evaluation completed 48 months after enrollment. The findings were triangulated with internal memos, reports and minutes of meetings, as well as with the theoretical literature. The study demonstrates that CDC harbours considerable benefits for people with disabilities and their carers. However, the study also suggests that, over time, carers may experience an increased sense of isolation and lack of support as a result of their involvement in the CDC programme. The paper argues that the development of safeguards addressing these weaknesses is crucial for the sustainability of CDC programmes in contexts where risk cannot be simply transferred onto consumers.

Staff members' perceptions of an animal-assisted activity.

PubMed

Bibbo, Jessica

2013-07-01

To examine the perceptions of staff members toward the implementation of an animal-assisted activity (AAA) in an outpatient regional cancer center. Quasi-experimental, post-test design. An adult outpatient regional cancer center in northern California. 34 facility staff members. Self-report questionnaire following four weeks of AAA visitation. Visits took place three times a week for a total of 12 visits. Perceptions of the AAA. Previous perceptions toward AAA influenced the perceptions of the visitation's efficacy. Direct and indirect interaction with the visiting AAA teams was positively associated with perceptions of the AAA. A disagreement occurred that the AAA had caused extra stress or work for staff. Enjoyment of interacting with the dog handler was not significantly different from interacting with the dog; however, it was more positively correlated to acceptance of the AAA. The study provided evidence that the AAA was generally accepted by staff members. Individual staff members' perceptions of dogs and AAAs can influence their receptivity to AAA interventions. Interaction with AAA teams should be voluntary and available for patients and staff members. AAA may be introduced into facilities without creating the perception of extra stress or work for staff members. Providing staff the opportunity to interact with visiting AAA teams may be beneficial for the success of such programs. The human handler in AAA teams may play a vital role in the staff acceptance of such programs.

Role of Lactobacillus plantarum MTCC1325 in membrane-bound transport ATPases system in Alzheimer’s disease-induced rat brain

PubMed Central

Mallikarjuna, Nimgampalle; Praveen, Kukkarasapalli; Yellamma, Kuna

2016-01-01

Introduction: Alzheimer’s disease (AD) is a neurodegenerative disorder, clinically characterized by memory dysfunction and progressive loss of cognition. No curative therapeutic or drug is available for the complete cure of this disease. The present study was aimed to evaluate the efficacy of Lactobacillus plantarum MTCC1325 in ATPases activity in the selected brain regions of rats induced with Alzheimer’s. Methods: For the study, 48 healthy Wistar rats were divided into four groups: group I as control group, group II as AD model (AD induced by intraperitoneal injection of D-Galactose, 120 mg/kg body weight for 6 weeks), group III as normal control rats which were orally administered only with L. plantarum MTCC1325 for 60 days, and group IV where the AD-induced rats simultaneously received oral treatment of L. plantarum MTCC1325 (10ml/kg body weight, 12×108 CFU/mL) for 60 days. The well known membrane bound transport enzymes including Na+, K+-ATPases, Ca2+-ATPases, and Mg2+-ATPases were assayed in the selected brain regions of hippocampus and cerebral cortex in all four groups of rats at selected time intervals. Results: Chronic injection of D-Galactose caused lipid peroxidation, oxidative stress, and mitochondrial dysfunction leading to the damage of neurons in the brain, finally bringing a significant decrease (-20%) in the brain total membrane bound ATPases over the controls. Contrary to this, treatment of AD-induced rats with L. plantarum MTCC1325 reverted all the constituents of ATPase enzymes to near normal levels within 30 days. Conclusion: Lactobacillus plantarum MTCC1325 exerted a beneficial action on the entire ATPases system in AD-induced rat brain by delaying neurodegeneration. PMID:28265536

Risk of abdominal aortic aneurysm (AAA) among male and female relatives of AAA patients.

PubMed

van de Luijtgaarden, Koen M; Rouwet, Ellen V; Hoeks, Sanne E; Stolker, Robert J; Verhagen, Hence Jm; Majoor-Krakauer, Danielle

2017-04-01

Sex affects the presentation, treatment, and outcomes of abdominal aortic aneurysm (AAA). Although AAAs are less prevalent in women, at least in the general population, women with an AAA have a poorer prognosis in comparison to men. Sex differences in the genetic predisposition for aneurysm disease remain to be established. In this study we investigated the familial risk of AAA for women compared to men. All living AAA patients included in a 2004-2012 prospective database were invited to the multidisciplinary vascular/genetics outpatient clinic between 2009 and 2012 for assessment of family history using detailed questionnaires. AAA risk for male and female relatives was calculated separately and stratified by sex of the AAA patients. Families of 568 AAA patients were investigated and 22.5% of the patients had at least one affected relative. Female relatives had a 2.8-fold and male relatives had a 1.7-fold higher risk than the estimated sex-specific population risk. Relatives of female AAA patients had a higher aneurysm risk than relatives of male patients (9.0 vs 5.9%, p = 0.022), corresponding to 5.5- and 2.0-fold increases in aneurysm risk in the female and male relatives, respectively. The risk for aortic aneurysm in relatives of AAA patients is higher than expected from population risk. The excess risk is highest for the female relatives of AAA patients and for the relatives of female AAA patients. These findings endorse targeted AAA family screening for female and male relatives of all AAA patients.

Coevolution of the ATPase ClpV, the Sheath Proteins TssB and TssC, and the Accessory Protein TagJ/HsiE1 Distinguishes Type VI Secretion Classes*

PubMed Central

Förster, Andreas; Planamente, Sara; Manoli, Eleni; Lossi, Nadine S.; Freemont, Paul S.; Filloux, Alain

2014-01-01

The type VI secretion system (T6SS) is a bacterial nanomachine for the transport of effector molecules into prokaryotic and eukaryotic cells. It involves the assembly of a tubular structure composed of TssB and TssC that is similar to the tail sheath of bacteriophages. The sheath contracts to provide the energy needed for effector delivery. The AAA+ ATPase ClpV disassembles the contracted sheath, which resets the systems for reassembly of an extended sheath that is ready to fire again. This mechanism is crucial for T6SS function. In Vibrio cholerae, ClpV binds the N terminus of TssC within a hydrophobic groove. In this study, we resolved the crystal structure of the N-terminal domain of Pseudomonas aeruginosa ClpV1 and observed structural alterations in the hydrophobic groove. The modification in the ClpV1 groove is matched by a change in the N terminus of TssC, suggesting the existence of distinct T6SS classes. An accessory T6SS component, TagJ/HsiE, exists predominantly in one of the classes. Using bacterial two-hybrid approaches, we showed that the P. aeruginosa homolog HsiE1 interacts strongly with ClpV1. We then resolved the crystal structure of HsiE1 in complex with the N terminus of HsiB1, a TssB homolog and component of the contractile sheath. Phylogenetic analysis confirmed that these differences distinguish T6SS classes that resulted from a functional co-evolution between TssB, TssC, TagJ/HsiE, and ClpV. The interaction of TagJ/HsiE with the sheath as well as with ClpV suggests an alternative mode of disassembly in which HsiE recruits the ATPase to the sheath. PMID:25305017

CXCL8 hyper-signaling in the aortic abdominal aneurysm.

PubMed

Kokje, Vivianne B C; Gäbel, Gabor; Dalman, Ron L; Koole, Dave; Northoff, Bernd H; Holdt, Lesca M; Hamming, Jaap F; Lindeman, Jan H N

2018-08-01

There are indications for elevated CXCL8 levels in abdominal aortic aneurysm disease (AAA). CXCL8 is concurrently involved in neutrophil-mediated inflammation and angiogenesis, two prominent and distinctive characteristics of AAA. As such we considered an evaluation of a role for CXCL8 in AAA progression relevant. ELISA's, real time PCR and array analysis were used to explore CXCL8 signaling in AAA wall samples. A role for CXCL8 in AAA disease was tested through the oral CXCR1/2 antagonist DF2156A in the elastase model of AAA disease. There is an extreme disparity in aortic wall CXCL8 content between AAA and aortic atherosclerotic disease (median [IQR] aortic wall CXCL8 content: 425 [141-1261] (AAA) vs. 23 [2.8-89] (atherosclerotic aorta) µg/g protein (P < 1 · 10 -14 )), and abundant expression of the CXCR1 and 2 receptors in AAA. Array analysis followed by pathway analysis showed that CXCL8 hyper-expression in AAA is followed increased by IL-8 signaling (Z-score for AAA vs. atherosclerotic control: 2.97, p < 0.0001). Interference with CXCL8 signaling through DF2156A fully abrogated AAA formation and prevented matrix degradation in the murine elastase model of AAA disease (p < 0.001). CXCL8-signaling is a prominent and distinctive feature of AAA, interference with the pathway constitutes a promising target for medical stabilization of AAA. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Spatial Analysis of Hospital Incidence and in Hospital Mortality of Abdominal Aortic Aneurysms in Germany: Secondary Data Analysis of Nationwide Hospital Episode (DRG) Data.

PubMed

Kuehnl, Andreas; Salvermoser, Michael; Erk, Alexander; Trenner, Matthias; Schmid, Volker; Eckstein, Hans-Henning

2018-06-01

This study aimed to analyze the spatial distribution and regional variation of the hospital incidence and in hospital mortality of abdominal aortic aneurysms (AAA) in Germany. German DRG statistics (2011-2014) were analysed. Patients with ruptured AAA (rAAA, I71.3, treated or not) and patients with non-ruptured AAA (nrAAA, I71.4, treated by open or endovascular aneurysm repair) were included. Age, sex, and risk standardisation was done using standard statistical procedures. Regional variation was quantified using systematic component of variation. To analyse spatial auto-correlation and spatial pattern, global Moran's I and Getis-Ord Gi* were calculated. A total of 50,702 cases were included. Raw hospital incidence of AAA was 15.7 per 100,000 inhabitants (nrAAA 13.1; all rAAA 2.7; treated rAAA 1.6). The standardised hospital incidence of AAA ranged from 6.3 to 30.3 per 100,000. Systematic component of variation proportion was 96% in nrAAA and 55% in treated rAAA. Incidence rates of all AAA were significantly clustered with above average values in the northwestern parts of Germany and below average values in the south and eastern regions. Standardised mortality of nrAAA ranged from 1.7% to 4.3%, with that of treated rAAA ranging from 28% to 52%. Regional variation and spatial distribution of standardised mortality was not different from random. There was significant regional variation and clustering of the hospital incidence of AAA in Germany, with higher rates in the northwest and lower rates in the southeast. There was no significant variation in standardised (age/sex/risk) mortality between counties. Copyright © 2018. Published by Elsevier B.V.

Update on Abdominal Aortic Aneurysm Research: From Clinical to Genetic Studies

PubMed Central

Kuivaniemi, Helena; Ryer, Evan J.; Elmore, James R.; Hinterseher, Irene; Smelser, Diane T.; Tromp, Gerard

2014-01-01

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta with a diameter of at least 3.0 cm. AAAs are often asymptomatic and are discovered as incidental findings in imaging studies or when the AAA ruptures leading to a medical emergency. AAAs are more common in males than females, in individuals of European ancestry, and in those over 65 years of age. Smoking is the most important environmental risk factor. In addition, a positive family history of AAA increases the person's risk for AAA. Interestingly, diabetes has been shown to be a protective factor for AAA in many large studies. Hallmarks of AAA pathogenesis include inflammation, vascular smooth muscle cell apoptosis, extracellular matrix degradation, and oxidative stress. Autoimmunity may also play a role in AAA development and progression. In this Outlook paper, we summarize our recent studies on AAA including clinical studies related to surgical repair of AAA and genetic risk factor and large-scale gene expression studies. We conclude with a discussion on our research projects using large data sets available through electronic medical records and biobanks. PMID:24834361

Endovascular repair vs open surgical repair of abdominal aortic aneurysms: comparative utilization trends from 2001 to 2006.

PubMed

Levin, David C; Rao, Vijay M; Parker, Laurence; Frangos, Andrea J; Sunshine, Jonathan H

2009-07-01

Within the past few years, endovascular aneurysm repair (EVAR) has come into use for the treatment of abdominal aortic aneurysms (AAAs). In many cases, EVAR has the potential to replace traditional open surgical repair (OSR), which is more invasive, risky, and expensive. The aim of this study was to determine to what extent EVAR is replacing OSR, whether the frequency of treatment is increasing with the advent of the less invasive approach, and which specialties are performing the procedures. The Medicare Part B data sets for 2001 through 2006 were studied. Procedure volume and utilization rates per 100,000 Medicare beneficiaries were determined for the 7 Current Procedural Terminology, fourth edition, procedure codes that describe EVAR and the 4 codes that describe OSR for AAA. Medicare's physician specialty codes were used to ascertain the specialties of the physician providers. A total of 31,965 OSRs for AAA were performed in Medicare beneficiaries in 2001, dropping to 15,665 by 2006 (-51%). In contrast, EVAR was carried out in 11,028 instances in 2001, increasing to 28,937 by 2006 (+162%). The utilization rate per 100,000 for OSR dropped from 90 to 42 (a rate decrease of 48) during the study period, while the rate for EVAR increased from 31 to 77 (a rate increase of 46). The combined utilization rate per 100,000 of the two types of interventions for AAA (EVAR and OSR) decreased from 121 in 2001 to 119 in 2006. In performing EVAR, procedure volume and market share in 2006 by specialty were 1) 22,003 procedures by surgeons, a 76% share; 2) 3,287 procedures by radiologists, an 11% share; 3) 1,915 procedures by cardiologists, a 7% share; and 4) 1,732 procedures by all other physicians, a 6% share. Treatment for AAA seems to be an example of the responsible use of new technology by physicians. The newer, less invasive, and less risky procedure (EVAR) is replacing the older and more invasive procedure (OSR) to a considerable degree. However, the overall combined utilization rate of both types of AAA treatment has remained stable in the Medicare population. There is thus no evidence to suggest that the introduction of the newer approach has led to the overtreatment of patients. Although radiologists do have a role in EVAR, surgeons strongly predominate.

Effect of a High-sucrose Diet on Abdominal Aortic Aneurysm Development in a Hypoperfusion-induced Animal Model.

PubMed

Miyamoto, Chie; Kugo, Hirona; Hashimoto, Keisuke; Sawaragi, Ayaka; Zaima, Nobuhiro; Moriyama, Tatsuya

2018-05-01

Abdominal aortic aneurysm (AAA) is a vascular disease that results in rupture of the abdominal aorta. The risk factors for the development of AAA include smoking, male sex, hypertension, and age. AAA has a high mortality rate, but therapy for AAA is restricted to surgery in cases of large aneurysms. Clarifying the effect of dietary food on the development of AAA would be helpful for patients with AAAs. However, the relationship between dietary habits and the development of AAA is largely unknown. In our previous study, we demonstrated that adipocytes in vascular wall can induce the rupture of AAA. Therefore, we focused on the diet-induced abnormal triglyceride metabolism, which has the potential to drive AAA development. In this study, we have evaluated the effects of a high-sucrose diet on the development of AAA in a vascular hypoperfusion-induced animal model. A high sucrose diet induced high serum TG level and fatty liver. However, the AAA rupture risk and the AAA diameter were not significantly different between the control and high-sucrose groups. The intergroup differences in the elastin degradation score and collagen-positive area were insignificant. Moreover, matrix metalloproteinases, macrophages, and monocyte chemoattractant protein-1-positive areas did not differ significantly between groups. These results suggest that a high-sucrose diet does not affect the appearance of vascular adipocyte and AAA development under the vascular hypoperfusion condition.

A comparison of an ATPase from the archaebacterium Halobacterium saccharovorum with the F1 moiety from the Escherichia coli ATP Synthase

NASA Technical Reports Server (NTRS)

Stan-Lotter, Helga; Hochstein, Lawrence I.

1989-01-01

A purified ATPase associated with membranes from Halobacterium saccharovorum was compared with the F sub 1 moiety from the Escherichia coli ATP Synthase. The halobacterial enzyme was composed of two major (I and II) and two minor subunits (III and IV), whose molecular masses were 87 kDa, 60 kDa, 29 kDa, and 20 kDa, respectively. The isoelectric points of these subunits ranged from 4.1 to 4.8, which in the case of the subunits I and II was consistent with the presence of an excess of acidic amino acids (20 to 22 Mol percent). Peptide mapping of sodium dodecylsulfate-denatured subunits I and II showed no relationship between the primary structures of the individual halobacterial subunits or similarities to the subunits of the F sub 1 ATPase (EC 3.6.1.34) from E. coli. Trypsin inactivation of the halobacterial ATPase was accompanied by the partial degradation of the major subunits. This observation, taken in conjunction with molecular masses of the subunits and the native enzyme, was consistent with the previously proposed stoichiometry of 2:2:1:1. These results suggest that H. saccharovorum, and possibly, Halobacteria in general, possess an ATPase which is unlike the ubiquitous F sub o F sub 1 - ATP Synthase.

48 CFR 301.270 - Executive Committee for Acquisition.

Code of Federal Regulations, 2012 CFR

2012-10-01

...). (10) Program Support Center (PSC). (11) Substance Abuse and Mental Health Services Administration..., Contracts and Grants (ASPR/OAMCG). (4) Centers for Disease Control and Prevention (CDC). (5) Centers for...

48 CFR 301.270 - Executive Committee for Acquisition.

Code of Federal Regulations, 2014 CFR

2014-10-01

...). (10) Program Support Center (PSC). (11) Substance Abuse and Mental Health Services Administration..., Contracts and Grants (ASPR/OAMCG). (4) Centers for Disease Control and Prevention (CDC). (5) Centers for...

48 CFR 301.270 - Executive Committee for Acquisition.

Code of Federal Regulations, 2013 CFR

2013-10-01

...). (10) Program Support Center (PSC). (11) Substance Abuse and Mental Health Services Administration..., Contracts and Grants (ASPR/OAMCG). (4) Centers for Disease Control and Prevention (CDC). (5) Centers for...

Sex- and Disease-Specific Inflammasome Signatures in Circulating Blood Leukocytes of Patients with Abdominal Aortic Aneurysm

PubMed Central

Wu, Xiaoyu; Cakmak, Sinan; Wortmann, Markus; Hakimi, Maani; Zhang, Jian; Böckler, Dittmar; Dihlmann, Susanne

2016-01-01

Male sex is a risk factor for abdominal aortic aneurysm (AAA). Within the AAA adventitia, infiltrating leukocytes express high levels of inflammasome components. To further elucidate the role of inflammatory cells in the pathogenesis of AAA, we here addressed expression and functionality of inflammasome components in peripheral blood mononuclear cells (PBMC) of AAA patients in association with sex. PBMC and plasma were isolated from 100 vascular patients, including 34 pairs of AAA patients and age/sex-matched non-AAA patients. Male PBMC were found to express significantly higher mRNA levels of AIM2, NLRP3, ASC (PYCARD), CASP1, CASP5, and IL1B (all P < 0.0001) than female PBMC. Within the male patients, PBMC of AAA patients displayed increased mRNA levels of NLRP3 (P = 0.044), CASP1 (P = 0.032) and IL1B (P = 0.0004) compared with matched non-AAA PBMC, whereas there was no difference between female AAA and non-AAA patients. The relative protein level of NLRP3 was significantly lower in PBMC lysates from all AAA patients than in matched controls (P = 0.038), whereas AIM2 and active Caspase-1 (p10) protein levels were significantly increased (P = 0.014 and P = 0.049). ELISA revealed significantly increased IL-1α (mean = 6.34 versus 0.01 pg/mL) and IL-1β plasma levels (mean = 12.07 versus 0.04 pg/mL) in AAA patients. The data indicate that male PBMC display a systemic proinflammatory state with primed inflammasomes that may contribute to AAA-pathogenesis. The AAA-specific inflammasome activation pattern suggests differential regulation of the sensors AIM2 and NLRP3 in inflammatory cells of AAA patients. PMID:27474483

Validation of cooking times and temperatures for thermal inactivation of Yersinia pestis strains KIM5 and CDC-A1122 in irradiated ground beef.

PubMed

Porto-Fett, Anna C S; Juneja, Vijay K; Tamplin, Mark L; Luchansky, John B

2009-03-01

Irradiated ground beef samples (ca. 3-g portions with ca. 25% fat) inoculated with Yersina pestis strain KIM5 (ca. 6.7 log CFU/g) were heated in a circulating water bath stabilized at 48.9, 50, 52.5, 55, 57.5, or 60 degrees C (120, 122, 126.5, 131, 135.5, and 140 degrees F, respectively). Average D-values were 192.17, 34.38, 17.11, 3.87, 1.32, and 0.56 min, respectively, with a corresponding z-value of 4.67 degrees C (8.41 degrees F). In related experiments, irradiated ground beef patties (ca. 95 g per patty with ca. 25% fat) were inoculated with Y. pestis strains KIMS or CDC-A1122 (ca. 6.0 log CFU/g) and cooked on an open-flame gas grill or on a clam-shell type electric grill to internal target temperatures of 48.9, 60, and 71.1 degrees C (120, 140, and 160 degrees F, respectively). For patties cooked on the gas grill, strain KIM5 populations decreased from ca. 6.24 to 4.32, 3.51, and < or = 0.7 log CFU/g at 48.9, 60, and 71.1 degrees C, respectively, and strain CDC-A1122 populations decreased to 3.46 log CFU/g at 48.9 degrees C and to < or = 0.7 log CFU/g at both 60 and 71.1 degrees C. For patties cooked on the clam-shell grill, strain KIM5 populations decreased from ca. 5.96 to 2.53 log CFU/g at 48.9 degrees C and to < or = 0.7 log CFU/g at 60 or 71.1 degrees C, and strain CDC-A1122 populations decreased from ca. 5.98 to < or = 0.7 log CFU/g at all three cooking temperatures. These data confirm that cooking ground beef on an open-flame gas grill or on a clam-shell type electric grill to the temperatures and times recommended by the U.S. Department of Agriculture and the U.S. Food and Drug Administration Food Code, appreciably lessens the likelihood, severity, and/or magnitude of consumer illness if the ground beef were purposefully contaminated even with relatively high levels of Y. pestis.

A novel mutation in the alpha-helix 1 of the C subunit of the F(1)/F(0) ATPase responsible for optochin resistance of a Streptococcus pneumoniae clinical isolate.

PubMed

Cogné, N; Claverys, J; Denis, F; Martin, C

2000-10-01

Previously reported mutations involved in optochin resistance of Streptococcus pneumoniae clinical isolates changed residues 48, 49 or 50, in the transmembrane alpha-helix 2 of the F(1)/F(0) ATPase subunit. We report here an unusual mutation which changes the sequence of the transmembrane alpha-helix 1 of the AtpC subunit. This mutation involves a Gly to Ser substitution resulting from a G to A transition at codon 14 of the atpC gene.

Color stability of silorane-based composites submitted to accelerated artificial ageing--an in situ study.

PubMed

Pires-de-Souza, Fernanda de Carvalho Panzeri; Garcia, Lucas da Fonseca Roberti; Roselino, Lourenço de Moraes Rego; Naves, Lucas Zago

2011-07-01

To assess the in situ color stability, surface and the tooth/restoration interface degradation of a silorane-based composite (P90, 3M ESPE) after accelerated artificial ageing (AAA), in comparison with other dimethacrylate monomer-based composites (Z250/Z350, 3M ESPE and Esthet-X, Dentsply). Class V cavities (25 mm(2) × 2 mm deep) were prepared in 48 bovine incisors, which were randomly allocated into 4 groups of 12 specimens each, according to the type of restorative material used. After polishing, 10 specimens were submitted to initial color readings (Easyshade, Vita) and 2 to analysis by scanning electronic microscopy (SEM). Afterwards, the teeth were submitted to AAA for 384 h, which corresponds to 1 year of clinical use, after which new color readings and microscopic images were obtained. The values obtained for the color analysis were submitted to statistical analysis (1-way ANOVA, Tukey, p<0.05). With regard to color stability, it was verified that all the composites showed color alteration above the clinically acceptable levels (ΔE ≥ 3.3), and that the silorane-based composite showed higher ΔE (18.6), with a statistically significant difference in comparison with the other composites (p<0.05). The SEM images showed small alterations for the dimethacrylate-based composites after AAA and extensive degradation for the silorane-based composite with a rupture at the interface between the matrix/particle. It may be concluded that the silorane-based composite underwent greater alteration with regard to color stability and greater surface and tooth/restoration interface degradation after AAA. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hypoperfusion of the Adventitial Vasa Vasorum Develops an Abdominal Aortic Aneurysm

PubMed Central

Sasaki, Takeshi; Sano, Masaki; Yamamoto, Naoto; Saito, Takaaki; Inuzuka, Kazunori; Hayasaka, Takahiro; Goto-Inoue, Naoko; Sugiura, Yuki; Sato, Kohji; Kugo, Hirona; Moriyama, Tatsuya; Konno, Hiroyuki; Setou, Mitsutoshi; Unno, Naoki

2015-01-01

The aortic wall is perfused by the adventitial vasa vasorum (VV). Tissue hypoxia has previously been observed as a manifestation of enlarged abdominal aortic aneurysms (AAAs). We sought to determine whether hypoperfusion of the adventitial VV could develop AAAs. We created a novel animal model of adventitial VV hypoperfusion with a combination of a polyurethane catheter insertion and a suture ligation of the infrarenal abdominal aorta in rats. VV hypoperfusion caused tissue hypoxia and developed infrarenal AAA, which had similar morphological and pathological characteristics to human AAA. In human AAA tissue, the adventitial VV were stenotic in both small AAAs (30–49 mm in diameter) and in large AAAs (> 50 mm in diameter), with the sac tissue in these AAAs being ischemic and hypoxic. These results indicate that hypoperfusion of adventitial VV has critical effects on the development of infrarenal AAA. PMID:26308526

Chemical structure-guided design of dynapyrazoles, cell-permeable dynein inhibitors with a unique mode of action

PubMed Central

Steinman, Jonathan B; Santarossa, Cristina C; Miller, Rand M; Yu, Lola S; Serpinskaya, Anna S; Furukawa, Hideki; Morimoto, Sachie; Tanaka, Yuta; Nishitani, Mitsuyoshi; Asano, Moriteru; Zalyte, Ruta; Ondrus, Alison E; Johnson, Alex G; Ye, Fan; Nachury, Maxence V; Fukase, Yoshiyuki; Aso, Kazuyoshi; Foley, Michael A; Gelfand, Vladimir I; Chen, James K; Carter, Andrew P; Kapoor, Tarun M

2017-01-01

Cytoplasmic dyneins are motor proteins in the AAA+ superfamily that transport cellular cargos toward microtubule minus-ends. Recently, ciliobrevins were reported as selective cell-permeable inhibitors of cytoplasmic dyneins. As is often true for first-in-class inhibitors, the use of ciliobrevins has in part been limited by low potency. Moreover, suboptimal chemical properties, such as the potential to isomerize, have hindered efforts to improve ciliobrevins. Here, we characterized the structure of ciliobrevins and designed conformationally constrained isosteres. These studies identified dynapyrazoles, inhibitors more potent than ciliobrevins. At single-digit micromolar concentrations dynapyrazoles block intraflagellar transport in the cilium and lysosome motility in the cytoplasm, processes that depend on cytoplasmic dyneins. Further, we find that while ciliobrevins inhibit both dynein's microtubule-stimulated and basal ATPase activity, dynapyrazoles strongly block only microtubule-stimulated activity. Together, our studies suggest that chemical-structure-based analyses can lead to inhibitors with improved properties and distinct modes of inhibition. DOI: http://dx.doi.org/10.7554/eLife.25174.001 PMID:28524820

Msp1 Is a Membrane Protein Dislocase for Tail-Anchored Proteins.

PubMed

Wohlever, Matthew L; Mateja, Agnieszka; McGilvray, Philip T; Day, Kasey J; Keenan, Robert J

2017-07-20

Mislocalized tail-anchored (TA) proteins of the outer mitochondrial membrane are cleared by a newly identified quality control pathway involving the conserved eukaryotic protein Msp1 (ATAD1 in humans). Msp1 is a transmembrane AAA-ATPase, but its role in TA protein clearance is not known. Here, using purified components reconstituted into proteoliposomes, we show that Msp1 is both necessary and sufficient to drive the ATP-dependent extraction of TA proteins from the membrane. A crystal structure of the Msp1 cytosolic region modeled into a ring hexamer suggests that active Msp1 contains a conserved membrane-facing surface adjacent to a central pore. Structure-guided mutagenesis of the pore residues shows that they are critical for TA protein extraction in vitro and for functional complementation of an msp1 deletion in yeast. Together, these data provide a molecular framework for Msp1-dependent extraction of mislocalized TA proteins from the outer mitochondrial membrane. Copyright © 2017 Elsevier Inc. All rights reserved.

VCP-dependent muscle degeneration is linked to defects in a dynamic tubular lysosomal network in vivo

PubMed Central

Johnson, Alyssa E; Shu, Huidy; Hauswirth, Anna G; Tong, Amy; Davis, Graeme W

2015-01-01

Lysosomes are classically viewed as vesicular structures to which cargos are delivered for degradation. Here, we identify a network of dynamic, tubular lysosomes that extends throughout Drosophila muscle, in vivo. Live imaging reveals that autophagosomes merge with tubular lysosomes and that lysosomal membranes undergo extension, retraction, fusion and fission. The dynamics and integrity of this tubular lysosomal network requires VCP, an AAA-ATPase that, when mutated, causes degenerative diseases of muscle, bone and neurons. We show that human VCP rescues the defects caused by loss of Drosophila VCP and overexpression of disease relevant VCP transgenes dismantles tubular lysosomes, linking tubular lysosome dysfunction to human VCP-related diseases. Finally, disruption of tubular lysosomes correlates with impaired autophagosome-lysosome fusion, increased cytoplasmic poly-ubiquitin aggregates, lipofuscin material, damaged mitochondria and impaired muscle function. We propose that VCP sustains sarcoplasmic proteostasis, in part, by controlling the integrity of a dynamic tubular lysosomal network. DOI: http://dx.doi.org/10.7554/eLife.07366.001 PMID:26167652

Viewing pre-60S maturation at a minute’s timescale

PubMed Central

Zisser, Gertrude; Ohmayer, Uli; Mauerhofer, Christina; Mitterer, Valentin; Klein, Isabella; Rechberger, Gerald N; Wolinski, Heimo; Prattes, Michael; Pertschy, Brigitte; Milkereit, Philipp

2018-01-01

Abstract The formation of ribosomal subunits is a highly dynamic process that is initiated in the nucleus and involves more than 200 trans-acting factors, some of which accompany the pre-ribosomes into the cytoplasm and have to be recycled into the nucleus. The inhibitor diazaborine prevents cytoplasmic release and recycling of shuttling pre-60S maturation factors by inhibiting the AAA-ATPase Drg1. The failure to recycle these proteins results in their depletion in the nucleolus and halts the pathway at an early maturation step. Here, we made use of the fast onset of inhibition by diazaborine to chase the maturation path in real-time from 27SA2 pre-rRNA containing pre-ribosomes localized in the nucleolus up to nearly mature 60S subunits shortly after their export into the cytoplasm. This allows for the first time to put protein assembly and disassembly reactions as well as pre-rRNA processing into a chronological context unraveling temporal and functional linkages during ribosome maturation. PMID:29294095

Structural Analysis of the Phenol-Responsive Sensory Domain of the Transcription Activator PoxR.

PubMed

Patil, Vinod Vikas; Park, Kwang-Hyun; Lee, Seung-Goo; Woo, Euijeon

2016-04-05

Positive phenol-degradative gene regulator (PoxR) is a σ(54)-dependent AAA+ ATPase transcription activator that regulates the catabolism of phenols. The PoxR sensory domain detects phenols and relays signals for the activation of transcription. Here we report the first structure of the phenol sensory domain bound to phenol and five derivatives. It exists as a tightly intertwined homodimer with a phenol-binding pocket buried inside, placing two C termini on the same side of the dimer. His102 and Trp130 interact with the hydroxyl group of the phenol in a cavity surrounded by rigid hydrophobic residues on one side and a flexible region on the other. Each monomer has a V4R fold with a unique zinc-binding site. A shift at the C-terminal helix suggests that there is a possible conformational change upon ligand binding. The results provide a structural basis of chemical effector binding for transcriptional regulation with broad implications for protein engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

α-SNAP Interferes with the Zippering of the SNARE Protein Membrane Fusion Machinery

PubMed Central

Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M.; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

2014-01-01

Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. PMID:24778182

Staphylococcal SCCmec elements encode an active MCM-like helicase and thus may be replicative

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mir-Sanchis, Ignacio; Roman, Christina A.; Misiura, Agnieszka

2016-08-29

Methicillin-resistant Staphylococcus aureus (MRSA) is a public-health threat worldwide. Although the mobile genomic island responsible for this phenotype, staphylococcal cassette chromosome (SCC), has been thought to be nonreplicative, we predicted DNA-replication-related functions for some of the conserved proteins encoded by SCC. We show that one of these, Cch, is homologous to the self-loading initiator helicases of an unrelated family of genomic islands, that it is an active 3'-to-5' helicase and that the adjacent ORF encodes a single-stranded DNA–binding protein. Our 2.9-Å crystal structure of intact Cch shows that it forms a hexameric ring. Cch, like the archaeal and eukaryotic MCM-familymore » replicative helicases, belongs to the pre–sensor II insert clade of AAA+ ATPases. Additionally, we found that SCC elements are part of a broader family of mobile elements, all of which encode a replication initiator upstream of their recombinases. Replication after excision would enhance the efficiency of horizontal gene transfer.« less

TRIP13 promotes error-prone nonhomologous end joining and induces chemoresistance in head and neck cancer

PubMed Central

Banerjee, Rajat; Russo, Nickole; Liu, Min; Basrur, Venkatesha; Bellile, Emily; Palanisamy, Nallasivam; Scanlon, Christina S.; van Tubergen, Elizabeth; Inglehart, Ronald C.; Metwally, Tarek; Mani, Ram-Shankar; Yocum, Anastasia; Nyati, Mukesh K.; Castilho, Rogerio M.; Varambally, Sooryanarayana; Chinnaiyan, Arul M.

2014-01-01

Head and neck cancer (SCCHN) is a common, aggressive, treatment-resistant cancer with a high recurrence rate and mortality, but the mechanism of treatment-resistance remains unclear. Here we describe a mechanism where the AAA-ATPase TRIP13 promotes treatment-resistance. Overexpression of TRIP13 in non-malignant cells results in malignant transformation. High expression of TRIP13 in SCCHN leads to aggressive, treatment-resistant tumors and enhanced repair of DNA damage. Using mass spectrometry, we identify DNA-PKcs complex proteins that mediate non homologous end joining (NHEJ), as TRIP13 binding partners. Using repair-deficient reporter systems, we show that TRIP13 promotes NHEJ, even when homologous recombination is intact. Importantly, overexpression of TRIP13 sensitizes SCCHN to an inhibitor of DNA-PKcs. Thus, this study defines a new mechanism of treatment resistance in SCCHN and underscores the importance of targeting NHEJ to overcome treatment failure in SCCHN and potentially in other cancers that overexpress TRIP13. PMID:25078033

Metazoan Hsp70 machines use Hsp110 to power protein disaggregation.

PubMed

Rampelt, Heike; Kirstein-Miles, Janine; Nillegoda, Nadinath B; Chi, Kang; Scholz, Sebastian R; Morimoto, Richard I; Bukau, Bernd

2012-11-05

Accumulation of aggregation-prone misfolded proteins disrupts normal cellular function and promotes ageing and disease. Bacteria, fungi and plants counteract this by solubilizing and refolding aggregated proteins via a powerful cytosolic ATP-dependent bichaperone system, comprising the AAA+ disaggregase Hsp100 and the Hsp70-Hsp40 system. Metazoa, however, lack Hsp100 disaggregases. We show that instead the Hsp110 member of the Hsp70 superfamily remodels the human Hsp70-Hsp40 system to efficiently disaggregate and refold aggregates of heat and chemically denatured proteins in vitro and in cell extracts. This Hsp110 effect relies on nucleotide exchange, not on ATPase activity, implying ATP-driven chaperoning is not required. Knock-down of nematode Caenorhabditis elegans Hsp110, but not an unrelated nucleotide exchange factor, compromises dissolution of heat-induced protein aggregates and severely shortens lifespan after heat shock. We conclude that in metazoa, Hsp70-Hsp40 powered by Hsp110 nucleotide exchange represents the crucial disaggregation machinery that reestablishes protein homeostasis to counteract protein unfolding stress.

Computational Growth and Remodeling of Abdominal Aortic Aneurysms Constrained by the Spine.

PubMed

Farsad, Mehdi; Zeinali-Davarani, Shahrokh; Choi, Jongeun; Baek, Seungik

2015-09-01

Abdominal aortic aneurysms (AAAs) evolve over time, and the vertebral column, which acts as an external barrier, affects their biomechanical properties. Mechanical interaction between AAAs and the spine is believed to alter the geometry, wall stress distribution, and blood flow, although the degree of this interaction may depend on AAAs specific configurations. In this study, we use a growth and remodeling (G&R) model, which is able to trace alterations of the geometry, thus allowing us to computationally investigate the effect of the spine for progression of the AAA. Medical image-based geometry of an aorta is constructed along with the spine surface, which is incorporated into the computational model as a cloud of points. The G&R simulation is initiated by local elastin degradation with different spatial distributions. The AAA-spine interaction is accounted for using a penalty method when the AAA surface meets the spine surface. The simulation results show that, while the radial growth of the AAA wall is prevented on the posterior side due to the spine acting as a constraint, the AAA expands faster on the anterior side, leading to higher curvature and asymmetry in the AAA configuration compared to the simulation excluding the spine. Accordingly, the AAA wall stress increases on the lateral, posterolateral, and the shoulder regions of the anterior side due to the AAA-spine contact. In addition, more collagen is deposited on the regions with a maximum diameter. We show that an image-based computational G&R model not only enhances the prediction of the geometry, wall stress, and strength distributions of AAAs but also provides a framework to account for the interactions between an enlarging AAA and the spine for a better rupture potential assessment and management of AAA patients.

Lifetime Risk and Risk Factors for Abdominal Aortic Aneurysm in a 24-Year Prospective Study: The ARIC Study (Atherosclerosis Risk in Communities).

PubMed

Tang, Weihong; Yao, Lu; Roetker, Nicholas S; Alonso, Alvaro; Lutsey, Pamela L; Steenson, Carol C; Lederle, Frank A; Hunter, David W; Bengtson, Lindsay G S; Guan, Weihua; Missov, Emil; Folsom, Aaron R

2016-12-01

Abdominal aortic aneurysm (AAA) is an important vascular disease in older adults, but data on lifetime risk of AAA are sparse. We examined lifetime risk of AAA in a community-based cohort and prospectively assessed the association between midlife cardiovascular risk factors and AAAs. In ARIC study (Atherosclerosis Risk in Communities), 15 792 participants were recruited at visit 1 in 1987 to 1989 and followed up through 2013. Longitudinal smoking status was defined using smoking behavior ascertained from visit 1 (1987-1989) to visit 4 (1996-1998). We followed up participants for incident, clinical AAAs using hospital discharge diagnoses, Medicare outpatient diagnoses, or death certificates through 2011 and identified 590 incident AAAs. An abdominal ultrasound was conducted in 2011 to 2013 in 5911 surviving participants, and 75 asymptomatic AAAs were identified. We estimated the lifetime risk of AAA from the index age 45 years through 85 years of age. At age 45, the lifetime risk for AAA was 5.6% (95% confidence interval, 4.8-6.1) and was higher in men (8.2%) and current smokers (10.5%). Smokers who quit smoking between visit 1 and visit 4 had a 29% lower AAA lifetime risk compared with continuous smokers but had a higher risk than pre-visit 1 quitters. The lifetime risk of rupture or medical intervention was 1.6% (95% confidence interval, 1.2-1.8). Smoking, white race, male sex, greater height, and greater low-density lipoprotein or total cholesterol were associated with an increased risk of clinical AAA and asymptomatic AAA. At least 1 in 9 middle-aged current smokers developed AAA in their lifetime. Smoking cessation reduced the lifetime risk of AAA. © 2016 American Heart Association, Inc.

From tissue iron retention to low systemic haemoglobin levels, new pathophysiological biomarkers of human abdominal aortic aneurysm.

PubMed

Martinez-Pinna, R; Lindholt, J S; Madrigal-Matute, J; Blanco-Colio, L M; Esteban-Salan, M; Torres-Fonseca, M M; Lefebvre, T; Delbosc, S; Laustsen, J; Driss, F; Vega de Ceniga, M; Gouya, L; Weiss, G; Egido, J; Meilhac, O; Michel, J-B; Martin-Ventura, J

2014-07-03

Iron deposits are observed in tissue of abdominal aortic aneurysm (AAA) patients, although the underlying mechanisms are not completely elucidated. Therefore we explored circulating markers of iron metabolism in AAA patients, and tested if they could serve as biomarkers of AAA. Increased red blood cell (RBC)-borne iron retention and transferrin, transferrin receptor and ferritin expression was observed in AAA tissue compared to control aorta (immunohistochemistry and western blot). In contrast, decreased circulating iron, transferrin, mean corpuscular haemoglobin concentration (MCHC) and haemoglobin concentration, along with circulating RBC count, were observed in AAA patients (aortic diameter >3 cm, n=114) compared to controls (aortic diameter <3 cm, n=88) (ELISA), whereas hepcidin concentrations were increased in AAA subjects (MS/MS assay). Moreover, iron, transferrin and haemoglobin levels were negatively, and hepcidin positively, correlated with aortic diameter in AAA patients. The association of low haemoglobin with AAA presence or aortic diameter was independent of specific risk factors. Moreover, MCHC negatively correlated with thrombus area in another cohort of AAA patients (aortic diameter 3-5 cm, n=357). We found that anaemia was significantly more prevalent in AAA patients (aortic diameter >5 cm, n=8,912) compared to those in patients with atherosclerotic aorto-iliac occlusive disease (n=17,737) [adjusted odds ratio=1.77 (95% confidence interval: 1.61;1.93)]. Finally, the mortality risk among AAA patients with anaemia was increased by almost 30% [adjusted hazard ratio: 1.29 (95% confidence interval: 1.16;1.44)] as compared to AAA subjects without anaemia. In conclusion, local iron retention and altered iron recycling associated to high hepcidin and low transferrin systemic concentrations could lead to reduced circulating haemoglobin levels in AAA patients. Low haemoglobin levels are independently associated to AAA presence and clinical outcome.

[Identifying barriers to screening for abdominal aortic aneurysm in general practice: Qualitative study of 14 general practitioners in Paris].

PubMed

Niclot, J; Stansal, A; Saint-Lary, O; Lazareth, I; Priollet, P

2018-05-01

Abdominal aortic aneurysm (AAA) is a silent pathology with often fatal consequences in case of rupture. AAA screening, recommended in France and many other countries, has shown its effectiveness in reducing specific mortality. However, AAA screening rate remains insufficient. To identify barriers to AAA screening in general practice. Qualitative study carried out during 2016 among general practitioners based in Paris. Fourteen physicians were included. Most of the barriers were related to the physician: unawareness about AAA and screening recommendations, considering AAA as a secondary question not discussed with the patient, abdominal aorta not included in cardiovascular assessment, no search for a familial history of AAA, AAA considered a question for the specialist, lack of time, lack of training, numerous screenings to propose, oversight. Some barriers are related to the patient: unawareness of the pathology and family history of AAA, refusal, questioning the pertinence of the doctor's comments, failure to respect the care pathway. Others are related to AAA: source of anxiety, low prevalence, rarity of complications. The remaining barriers are related to screening: cost-benefit and risk-benefit ratios, sonographer unavailability, constraint for the patient, overmedicalization. Information and training of general practitioners about AAA must be strengthened in order to optimize AAA screening and reduce specific mortality. Copyright © 2018. Published by Elsevier Masson SAS.

Matricellular protein CCN3 mitigates abdominal aortic aneurysm

PubMed Central

Zhang, Chao; van der Voort, Dustin; Shi, Hong; Qing, Yulan; Hiraoka, Shuichi; Takemoto, Minoru; Yokote, Koutaro; Moxon, Joseph V.; Norman, Paul; Rittié, Laure; Atkins, G. Brandon; Gerson, Stanton L.; Shi, Guo-Ping; Golledge, Jonathan; Dong, Nianguo; Perbal, Bernard; Prosdocimo, Domenick A.

2016-01-01

Abdominal aortic aneurysm (AAA) is a major cause of morbidity and mortality; however, the mechanisms that are involved in disease initiation and progression are incompletely understood. Extracellular matrix proteins play an integral role in modulating vascular homeostasis in health and disease. Here, we determined that the expression of the matricellular protein CCN3 is strongly reduced in rodent AAA models, including angiotensin II–induced AAA and elastase perfusion–stimulated AAA. CCN3 levels were also reduced in human AAA biopsies compared with those in controls. In murine models of induced AAA, germline deletion of Ccn3 resulted in severe phenotypes characterized by elastin fragmentation, vessel dilation, vascular inflammation, dissection, heightened ROS generation, and smooth muscle cell loss. Conversely, overexpression of CCN3 mitigated both elastase- and angiotensin II–induced AAA formation in mice. BM transplantation experiments suggested that the AAA phenotype of CCN3-deficient mice is intrinsic to the vasculature, as AAA was not exacerbated in WT animals that received CCN3-deficient BM and WT BM did not reduce AAA severity in CCN3-deficient mice. Genetic and pharmacological approaches implicated the ERK1/2 pathway as a critical regulator of CCN3-dependent AAA development. Together, these results demonstrate that CCN3 is a nodal regulator in AAA biology and identify CCN3 as a potential therapeutic target for vascular disease. PMID:26974158

Dependence of renal (Na+ + k+)-adenosine triphosphatase activity on thyroid status.

PubMed

Lo, S C; August, T R; Liberman, U A; Edelman, I S

1976-12-25

In thyroidectomized rats, a single injection of L-2,,5,2'-triiodothyronine (T3) (50mug/100 g body weight) elicited at 45% increase in (Na+ + k+)-dependent adenosine triphosphatase (NaK-ATPase) activity of the membrane-rich fraction of renal cortex at the optimal time of response, 48 h after injection. Three successive doses of T3 (50 mug/100 g body weight), given on alternate days, increased NaK-ATPase by 67% in the renal cortex but had no significant effect on the outer medulla or the papilla. Moreover, T3 had no effect on Mg2+-dependent adenosine trisphatase (MgATPase) in cortex, cedulla, or papilla. Three doses of T3 (50 mug/100 g body weight) given on alternate days to thyroidectomized rats elecited a 134, 79, and 46% increase in Vmax for ATP, Na4, and K+, respectively. There were no changes in the Km for ATP or the K1/2 values for Na+ and K+. Two methods were used to estimate the effect of T3 on the number of NaK-ATPase units (assumed to represent the number of Na+ pump sites); rat renal plasma membrane fractions were incubated with [gamma-32P]ATP, Mg2+, and Na+; the 32P-labeled membrane protein yeild was quantitatively dependent on Na+ and was hydrolyzed on addition of K+. There was a linear correlation between the specific activity of NaK-ATPase (Vmax) and the amount of phosphorylated intermediate formed, in renal cortical membrane fractions from thyroidectomized rats given T3 or the diluent. There was also a linear correlation between the specific activity of NaK-ATPase (Vmax) and the amount of [3H]ouabain specifically bound (Na+-, Mg2+-, APT-dependent) to the NaK-ATPase preparation. Injection of T3 resulted in a 70% increase in NaK-ATPase activity, a 79% increase in formation of the phosphorylated intermediate, and a 65% increase in the [H]ouabain specifically bound to the NaK-ATPase system. The T3-dependent increases in Vmax for ATP, Na+, and K+ and the proportionate increases in the phosphorylated intermediate and in the amount of [3H]ouabain bound indicate that T3 increases the number of NaK-ATPase units and that this increase accounts for the increase in NaK-ATPase activity.

Designation as “Unfit for Open Repair” Is Associated With Poor Outcomes After Endovascular Aortic Aneurysm Repair

PubMed Central

De Martino, Randall R.; Brooke, Benjamin S.; Robinson, William; Schanzer, Andres; Indes, Jeffrey E.; Wallaert, Jessica B.; Nolan, Brian W.; Cronenwett, Jack L.; Goodney, Philip P.

2014-01-01

Background Endovascular aortic aneurysm repair (EVAR) is often offered to patients with abdominal aortic aneurysms (AAAs) considered preoperatively to be unfit for open AAA repair (oAAA). This study describes the short- and long-term outcomes of patients undergoing EVAR with AAAs <6.5 cm who are considered unfit for oAAA. Methods and Results We analyzed elective EVARs for AAAs <6.5 cm diameter in the Vascular Study Group of New England (2003–2011). Patients were designated as fit or unfit for oAAA by the treating surgeon. End points included in-hospital major adverse events and long-term mortality. We identified patient characteristics associated with being unfit for open repair and predictors of survival using multivariable analyses. Of 1653 EVARs, 309 (18.7%) patients were deemed unfit for oAAA. These patients were more likely to have advanced age, cardiac disease, chronic obstructive pulmonary disease, and larger aneurysms at the time of repair (54 versus 56 mm, P=0.001). Patients unfit for oAAA had higher rates of cardiac (7.8% versus 3.1%, P<0.01) and pulmonary (3.6 versus 1.6, P<0.01) complications and worse survival rates at 5 years (61% versus 80%; log rank P<0.01) compared with those deemed fit for oAAA. Finally, patients designated as unfit for oAAA had worse survival, even adjusting for patient characteristics and aneurysm size (hazard ratio, 1.6; 95% confidence interval, 1.2–2.2; P<0.01). Conclusions In patients with AAAs <6.5 cm, designation by the operating surgeon as unfit for oAAA provides insight into both short- and long-term efficacy of EVAR. Patients unable to tolerate oAAA may not benefit from EVAR unless their risk of AAA rupture is very high. PMID:24046399

6-Mercaptopurine (6-MP) induces cell cycle arrest and apoptosis of neural progenitor cells in the developing fetal rat brain.

PubMed

Kanemitsu, H; Yamauchi, H; Komatsu, M; Yamamoto, S; Okazaki, S; Uchida, K; Nakayama, H

2009-01-01

6-Mercaptopurine (6-MP), an analogue of hypoxanthine, is used in the therapy of acute lymphoblastic leukemia and causes fetal neurotoxicity. To clarify the mechanisms of 6-MP-induced fetal neurotoxicity leading to the cell cycle arrest and apoptosis of neural progenitor cells, pregnant rats were treated with 50 mg/kg 6-MP on embryonic day (E) 13, and the fetal telencephalons were examined at 12 to 72 h (h) after treatment. Flow-cytometric analysis confirmed an accumulation of cells at G2/M, S, and sub-G1 (apoptotic cells) phases from 24 to 72 h. The number of phosphorylated histone H3-positive cells (mitotic cells) decreased from 36 to 72 h, and the phosphorylated (active) form of p53 protein, which is a mediator of apoptosis and cell cycle arrest, increased from 24 to 48 h. An executor of p53-mediated cell cycle arrest, p21, showed intense overexpression at both the mRNA and protein levels from 24 to 72 h. Cdc25A protein, which is needed for the progression of S phase, decreased at 36 and 48 h. In addition, phosphorylated cdc2 protein, which is an inactive form of cdc2 necessary for G2/M progression, increased from 24 to 48 h. These results suggest that 6-MP induced G2/M arrest, delayed S-phase progression, and finally induced apoptosis of neural progenitor cells mediated by p53 in the fetal rat telencephalon.

Calmodulin antagonists have differential effects on Ca/sup 2 +/ uptake, (Ca/sup 2 +/ + Mg/sup 2 +/)-ATPase and Ca/sup 2 +/ release in hepatic endoplasmic reticulum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delfert, D.M.; Koepnick, S.; McDonald, J.M.

1986-05-01

The effect of calmodulin (CaM) antagonists on Ca/sup 2 +/ handling by hepatic endoplasmic reticulum (ER) was studied. Ca/sup 2 +/ uptake by saponin-permeabilized hepatocytes or isolated ER was measured using /sup 45/Ca/sup 2 +/ in a filtration assay in the presence of 0.09 ..mu..M free (Ca/sup 2 +/) and inhibitors of mitochondrial Ca/sup 2 +/ transport. Each CaM-antagonist (chlorpromazine, CPZ; trifluoperazine, TFP; calmidazolium, W7 and 48/80) showed a dose-dependent inhibition of Ca/sup 2 +/ accumulation in permeabilized hepatocytes. Both the initial rate and steady state values for Ca/sup 2 +/ uptake were reduced by 50% with 40 ..mu..M calmidazolium,more » 100 ..mu..M TFP, 150..mu..M W7, 150 ..mu..M CPZ and 300 ..mu..M 48/80. Using isolated ER both calmidazolium (20 ..mu..M) and W7 (150 ..mu..M) inhibited the initial rate and steady state level of Ca/sup 2 +/ accumulation. At this concentration calmidazolium inhibited the initial rate of (Ca/sup 2 +/ + Mg/sup 2 +/)-ATPase activity, and enhanced Ca/sup 2 +/ release. In contrast, W7 had no effect on these parameters. These results suggest that the reduced level of Ca/sup 2 +/ uptake into ER vesicles in the presence of calmidazolium may result from inhibition of the (Ca/sup 2 +/ + Mg/sup 2 +/)-ATPase as well as induction of Ca/sup 2 +/ release, while W7 may act to uncouple Ca/sup 2 +/ transport from its (Ca/sup 2 +/ + Mg/sup 2 +/)-ATPase counterpart.« less

A Three-Ring Circus: Metabolism of the Three Proteogenic Aromatic Amino Acids and Their Role in the Health of Plants and Animals.

PubMed

Parthasarathy, Anutthaman; Cross, Penelope J; Dobson, Renwick C J; Adams, Lily E; Savka, Michael A; Hudson, André O

2018-01-01

Tyrosine, phenylalanine and tryptophan are the three aromatic amino acids (AAA) involved in protein synthesis. These amino acids and their metabolism are linked to the synthesis of a variety of secondary metabolites, a subset of which are involved in numerous anabolic pathways responsible for the synthesis of pigment compounds, plant hormones and biological polymers, to name a few. In addition, these metabolites derived from the AAA pathways mediate the transmission of nervous signals, quench reactive oxygen species in the brain, and are involved in the vast palette of animal coloration among others pathways. The AAA and metabolites derived from them also have integral roles in the health of both plants and animals. This review delineates the de novo biosynthesis of the AAA by microbes and plants, and the branching out of AAA metabolism into major secondary metabolic pathways in plants such as the phenylpropanoid pathway. Organisms that do not possess the enzymatic machinery for the de novo synthesis of AAA must obtain these primary metabolites from their diet. Therefore, the metabolism of AAA by the host animal and the resident microflora are important for the health of all animals. In addition, the AAA metabolite-mediated host-pathogen interactions in general, as well as potential beneficial and harmful AAA-derived compounds produced by gut bacteria are discussed. Apart from the AAA biosynthetic pathways in plants and microbes such as the shikimate pathway and the tryptophan pathway, this review also deals with AAA catabolism in plants, AAA degradation via the monoamine and kynurenine pathways in animals, and AAA catabolism via the 3-aryllactate and kynurenine pathways in animal-associated microbes. Emphasis will be placed on structural and functional aspects of several key AAA-related enzymes, such as shikimate synthase, chorismate mutase, anthranilate synthase, tryptophan synthase, tyrosine aminotransferase, dopachrome tautomerase, radical dehydratase, and type III CoA-transferase. The past development and current potential for interventions including the development of herbicides and antibiotics that target key enzymes in AAA-related pathways, as well as AAA-linked secondary metabolism leading to antimicrobials are also discussed.

A Three-Ring Circus: Metabolism of the Three Proteogenic Aromatic Amino Acids and Their Role in the Health of Plants and Animals

PubMed Central

Parthasarathy, Anutthaman; Cross, Penelope J.; Dobson, Renwick C. J.; Adams, Lily E.; Savka, Michael A.; Hudson, André O.

2018-01-01

Tyrosine, phenylalanine and tryptophan are the three aromatic amino acids (AAA) involved in protein synthesis. These amino acids and their metabolism are linked to the synthesis of a variety of secondary metabolites, a subset of which are involved in numerous anabolic pathways responsible for the synthesis of pigment compounds, plant hormones and biological polymers, to name a few. In addition, these metabolites derived from the AAA pathways mediate the transmission of nervous signals, quench reactive oxygen species in the brain, and are involved in the vast palette of animal coloration among others pathways. The AAA and metabolites derived from them also have integral roles in the health of both plants and animals. This review delineates the de novo biosynthesis of the AAA by microbes and plants, and the branching out of AAA metabolism into major secondary metabolic pathways in plants such as the phenylpropanoid pathway. Organisms that do not possess the enzymatic machinery for the de novo synthesis of AAA must obtain these primary metabolites from their diet. Therefore, the metabolism of AAA by the host animal and the resident microflora are important for the health of all animals. In addition, the AAA metabolite-mediated host-pathogen interactions in general, as well as potential beneficial and harmful AAA-derived compounds produced by gut bacteria are discussed. Apart from the AAA biosynthetic pathways in plants and microbes such as the shikimate pathway and the tryptophan pathway, this review also deals with AAA catabolism in plants, AAA degradation via the monoamine and kynurenine pathways in animals, and AAA catabolism via the 3-aryllactate and kynurenine pathways in animal-associated microbes. Emphasis will be placed on structural and functional aspects of several key AAA-related enzymes, such as shikimate synthase, chorismate mutase, anthranilate synthase, tryptophan synthase, tyrosine aminotransferase, dopachrome tautomerase, radical dehydratase, and type III CoA-transferase. The past development and current potential for interventions including the development of herbicides and antibiotics that target key enzymes in AAA-related pathways, as well as AAA-linked secondary metabolism leading to antimicrobials are also discussed. PMID:29682508

Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.

PubMed

Klarskov, Klaus; Gagnon, Hugo; Racine, Mathieu; Boudreault, Pierre-Luc; Normandin, Chad; Marsault, Eric; Gleich, Gerald J; Naylor, Stephen

2018-05-22

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA 1 -343) and linear (AAA 2 -343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA 1 -343 and AAA 2 -343. We structurally characterized eight new AAA 1 -XXX/AAA 2 -XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA 1 -315; n-octanoic acid (n-C8:0) for AAA 2 -315; 6-methyloctanoic acid (anteiso-C9:0) for AAA 1 -329; n-nonanoic acid (n-C9:0) for AAA 2 -329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA 1 -385; n-tridecanoic acid (n-C13:0) for AAA 2 -385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA 1 -399; and n-tetradecanoic acid (n-C14:0) for AAA 2 -399. The concentration levels for these contaminants were estimated to be 0.1-7.9 μg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Hindlimb Unweighting on Single Soleus Fiber Maximal Shortening Velocity and ATPase Activity

NASA Technical Reports Server (NTRS)

McDonald, K. S.; Fitts, R. H.

1993-01-01

This study characterizes the time course of change in single soleus muscle fiber size and function elicited by hindlimb un weighting (HU) and analyzes the extent to which varying durations of HU altered maximal velocity of shortening (V(sub o)), myofibrillar adenosinetriphosphatase (ATPase), and relative content of slow and fast myosin in individual soleus fibers. After 1, 2, or 3 weeks of HU, soleus muscle bundles were prepared and stored in skinning solution at -20 C. Single fibers were isolated and mounted between a motor arm and a transducer, and fiber force, V(sub o), and ATPase activity were measured. Fiber myosin content was determined by one-dimensional sodium dodecyl sulfate- (SDS) polyacrylamide gel electrophoresis. After 1, 2, and 3 weeks of HU, soleus fibers exhibited a progressive reduction in fiber diameter (16, 22, and 42%, respectively) and peak force (42, 48, and 7%, respectively). Peak specific tension was significantly reduced after 1 week of HU (18%) and showed no further change in 2-3 weeks of HU. During 1 and 3 wk of HU, fiber V(sub o) and ATPase showed a significant increase. By 3 week, V(sub o) had increased from 1.32 +/- 0.04 to 2.94 +/- 0.17 fiber lengths/s and fiber ATPase from 291 +/- 16 to 1064 +/- 128 micro-M min(sub -1) mm(sub -3). The percent fibers expressing fast myosin heavy chain increased from 4% to 29% by 3 week of HU, and V(sub o) and ATPase activity within a fiber were highly correlated. However, a large population of fibers after 1, 2, and 3 weeks of HU showed increases in V(sub o) and ATPase but displayed the same myosin protein profile on SDS gels as control fibers. The mechanism eliciting increased fiber V(sub o) and ATPase activity was not obvious but may have been due to increases in fast myosin that went undetected on SDS gels and/or other factors unrelated to the myosin filament.

AAA Foundation for Traffic Safety

MedlinePlus

... of Top Deadly Mistakes Made by Teen Drivers -- AAA AAA: Road debris causes avoidable crashes, deaths Save the ... and 500 deaths! Foundation News Stay Tuned New AAA Foundation for Traffic Safety website coming Fall 2017 ...

Achados incidentais de aneurismas torácicos e abdominais

PubMed Central

Góes, Adenauer Marinho de Oliveira; Mascarenhas, Bárbara Íris; Rodrigues, Sofia Cunha; de Andrade, Mariseth Carvalho; Franco, Reinaldo Sergio Monteiro

2016-01-01

Resumo Contexto Os aneurismas de aorta abdominal (AAAs) são os mais comuns. A incidência anual de ruptura do AAA é de oito casos por 100.000 habitantes. A detecção incidental pode beneficiar o paciente, desde que o diâmetro seja monitorado e o paciente receba o tratamento adequado. Objetivos Estimar a prevalência do diagnóstico incidental de aneurisma de aorta torácica (AAT) e de AAA em tomografias computadorizadas (TCs); avaliar a prevalência de sexo e idade dos pacientes e determinar quais as artérias acometidas e as características morfológicas dos aneurismas; determinar quais as indicações de TC mais associadas ao diagnóstico incidental de aneurismas. Métodos Estudo descritivo, retrospectivo e randomizado. Critérios de inclusão: pacientes com 50 anos ou mais submetidos a TC de tórax, abdome ou pelve. Critérios de exclusão: acompanhamento ou suspeita diagnóstica de aneurismas. Foram utilizados protocolos com questões sobre dados demográficos e anatômicos. Resultados Foram analisados 1.202 laudos radiológicos. Detectados 27 aneurismas (prevalência de 2,2%). Pacientes: 60% do sexo masculino e 40% do sexo feminino (p < 0,05). Localização: 13 casos (48,2%) na aorta ascendente (AAT); 7 (25,9%) na aorta infrarrenal (AAA); 2 (7,4%) aorta na transição toracoabdominal (ATA); 2 (7,4%) na ilíaca comum; 1 (3,7%) na ilíaca interna; 1 (3,7%) na artéria esplênica; e 1 (3,7%) na artéria renal. Conclusões A maioria dos pacientes foi do sexo masculino (60%); houve maior frequência de AAT (diâmetro médio de 4,1 cm), seguido de AAA (diâmetro médio de 4,0 cm) e ATA (diâmetro médio de 3,9 cm). A principal indicação para a realização de TC associada ao diagnóstico incidental de aneurismas foi em função de sintomas respiratórios. PMID:29930574

Aryl acylamidase activity exhibited by butyrylcholinesterase is higher in chick than in horse, but much lower than in fetal calf serum.

PubMed

Weitnauer, E; Robitzki, A; Layer, P G

1998-10-02

Several side activities have been attributed to butyrylcholinesterase (BChE), including aryl acylamidase (AAA) activity, which is an amidase-like activity with unknown physiological function splitting the artificial substrate o-nitroacetanilide. For avians, extensive developmental data have pointed to neurogenetic functions of BChE, however, a possible AAA activity of BChE has not been studied. In this study, we first compare the relative levels of AAA exhibited by BChE in whole sera from chick, fetal calves (FCS) and horse. Remarkably, FCS exhibits a 400-fold higher ratio of AAA/BChE than horse and 80-fold higher than chick serum. We then show that an immunoisolated preparation of BChE from chicken serum presents significant activity for AAA. Both in sera and with the purified enzyme, the AAA activity is fully inhibited by anticholinesterase drugs, showing that AAA activity is exclusively conveyed by the BChE molecule. Noticeably, AAA inhibition even occurs at lower drug concentrations than that of BChE activity itself. Moreover, AAA is sensitive to serotonin. These data indicate that (1) AAA is a general feature of serum BChE of vertebrates including avians, (2) AAA is effectively inhibited by cholinergic and serotonergic agents, and (3) AAA may have a developmental role, since it is much pronounced in a serum from fetal animals. Functionally, deamination of neuropeptides, a link between cholinergic and serotonergic neurotransmitter systems, and roles in lipoprotein metabolism could be relevant.

The brief negative symptom scale (BNSS): Sensitivity to treatment effects.

PubMed

Kirkpatrick, Brian; Saoud, Jay B; Strauss, Gregory P; Ahmed, Anthony O; Tatsumi, Kazunori; Opler, Mark; Luthringer, Remy; Davidson, Michael

2017-12-21

The Brief Negative Symptom Scale (BNSS) grew out of a recommendation by the NIMH-sponsored Consensus Development Conference on Negative Symptoms that a scale based on contemporary concepts be developed. We assessed sensitivity to change of the BNSS in a trial of MIN-101, which showed efficacy for negative symptoms (PANSS pentagonal model) at daily doses of 32 and 64mg/day. Using mixed-effects model for repeated measures, we examined change in BNSS total score and in the BNSS factors of anhedonia/avolition/asociality (AAA), and expressivity (EXP). Compared to placebo, the 64mg group (N=83) showed a significant decrease in BNSS total score (effect size d [ES] 0.56, p<0.01) and both factor scores (AAA ES=0.48, EXP ES=0.46, p<0.02 for both). Patients in the trial had minimal depression and positive symptom scores; covarying for disorganization, positive symptoms, or anxiety/depression did not cause a meaningful change in the significance of the BNSS total or factor scores in this group. The 32mg group (N=78) did not differ significantly from placebo (N=83) on BNSS total score (ES=0.33, p<0.09), AAA (ES=0.25, p<0.20) or EXP (ES=0.30, p<0.12) scores. These results demonstrate the BNSS is sensitive to change. Copyright © 2017. Published by Elsevier B.V.

The Diverse AAA+ Machines that Repair Inhibited Rubisco Active Sites

PubMed Central

Mueller-Cajar, Oliver

2017-01-01

Gaseous carbon dioxide enters the biosphere almost exclusively via the active site of the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). This highly conserved catalyst has an almost universal propensity to non-productively interact with its substrate ribulose 1,5-bisphosphate, leading to the formation of dead-end inhibited complexes. In diverse autotrophic organisms this tendency has been counteracted by the recruitment of dedicated AAA+ (ATPases associated with various cellular activities) proteins that all use the energy of ATP hydrolysis to remodel inhibited Rubisco active sites leading to release of the inhibitor. Three evolutionarily distinct classes of these Rubisco activases (Rcas) have been discovered so far. Green and red-type Rca are mostly found in photosynthetic eukaryotes of the green and red plastid lineage respectively, whereas CbbQO is associated with chemoautotrophic bacteria. Ongoing mechanistic studies are elucidating how the various motors are utilizing both similar and contrasting strategies to ultimately perform their common function of cracking the inhibited Rubisco active site. The best studied mechanism utilized by red-type Rca appears to involve transient threading of the Rubisco large subunit C-terminal peptide, reminiscent of the action performed by Clp proteases. As well as providing a fascinating example of convergent molecular evolution, Rca proteins can be considered promising crop-improvement targets. Approaches aiming to replace Rubisco in plants with improved enzymes will need to ensure the presence of a compatible Rca protein. The thermolability of the Rca protein found in crop plants provides an opportunity to fortify photosynthesis against high temperature stress. Photosynthesis also appears to be limited by Rca when light conditions are fluctuating. Synthetic biology strategies aiming to enhance the autotrophic CO2 fixation machinery will need to take into consideration the requirement for Rubisco activases as well as their properties. PMID:28580359

Abortion surveillance--United States, 2000.

PubMed

Elam-Evans, Laurie D; Strauss, Lilo T; Herndon, Joy; Parker, Wilda Y; Bowens, Sonya V; Zane, Suzanne; Berg, Cynthia J

2003-11-28

CDC began abortion surveillance in 1969 to document the number and characteristics of women obtaining legal induced abortions. This report summarizes and describes data reported to CDC regarding legal induced abortions obtained in the United States in 2000. For each year since 1969, CDC has compiled abortion data by state or area of occurrence. During 1973-1997, data were received from or estimated for 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City. In 1998 and 1999, CDC compiled abortion data from 48 reporting areas. Alaska, California, New Hampshire, and Oklahoma did not report, and data for these areas were not estimated. In 2000, Oklahoma again reported these data, increasing the number of reporting areas to 49. A total of 857,475 legal induced abortions were reported to CDC for 2000 from 49 reporting areas, representing a 0.5% decrease from the 861,789 legal induced abortions reported by 48 reporting areas for 1999 and a 1.3% decrease for the same 48 reporting areas that reported in 1999. The abortion ratio, defined as the number of abortions per 1,000 live births, was 246 in 2000 (for the same 48 reporting areas as 1999), compared with 256 reported for 1999. This represents a 3.8% decline in the abortion ratio. The abortion rate (for the same 48 reporting areas as 1999) was 16 per 1,000 women aged 15-44 years for 2000. This was also a 3.8% decrease from the rate reported for procedures performed during 1997-1999 for the same 48 reporting areas. The highest percentages of reported abortions were for women aged <25 years (52%), women who were white (57%), and unmarried women (81%). Fifty-eight percent of all abortions for which gestational age was reported were performed at < or =8 weeks of gestation, and 88% were performed before 13 weeks. From 1992 (when detailed data regarding early abortions were first collected) through 2000, steady increases have occurred in the percentage of abortions performed at < or =6 weeks of gestation. Few abortions were performed after 15 weeks of gestation; 4.3% were obtained at 16-20 weeks and 1.4% were obtained at > or =21 weeks. A total of 31 reporting areas submitted data stating that they performed medical (nonsurgical) procedures, making up 1.0% of all reported procedures from the 42 areas with adequate reporting on type of procedure. In 1998 and 1999 (the most recent years for which data are available), 14 women died as a result of complications from known legal induced abortion. Ten of these deaths occurred in 1998 and four occurred in 1999; no deaths were associated with known illegal abortion. From 1990 through 1997, the number of legal induced abortions gradually declined. In 1998 and 1999, the number of abortions continued to decrease when comparing the same 48 reporting areas. In 2000, even with one additional reporting state, the number of abortions declined slightly. In 1998 and 1999, as in previous years, deaths related to legal induced abortions occurred rarely (<1 death per 100,000 abortions). Abortion surveillance in the United States continues to provide data necessary for examining trends in numbers and characteristics of women who obtain legal induced abortions and for increasing understanding of one additional aspect of the spectrum of pregnancy outcomes. Policy makers and program planners need these data to improve the health and well-being of women and infants.

A Novel Mechanism of Regulating the ATPase VPS4 by Its Cofactor LIP5 and the Endosomal Sorting Complex Required for Transport (ESCRT)-III Protein CHMP5

DOE PAGES

Vild, Cody J.; Li, Yan; Guo, Emily Z.; ...

2015-01-30

Disassembly of the endosomal sorting complex required for transport (ESCRT) machinery from biological membranes is a critical final step in cellular processes that require the ESCRT function. This reaction is catalyzed by VPS4, an AAA-ATPase whose activity is tightly regulated by a host of proteins, including LIP5 and the ESCRT-III proteins. In this paper, we present structural and functional analyses of molecular interactions between human VPS4, LIP5, and the ESCRT-III proteins. The N-terminal domain of LIP5 (LIP5NTD) is required for LIP5-mediated stimulation of VPS4, and the ESCRT-III protein CHMP5 strongly inhibits the stimulation. Both of these observations are distinct frommore » what was previously described for homologous yeast proteins. The crystal structure of LIP5NTD in complex with the MIT (microtubule-interacting and transport)-interacting motifs of CHMP5 and a second ESCRT-III protein, CHMP1B, was determined at 1 Å resolution. It reveals an ESCRT-III binding induced moderate conformational change in LIP5NTD, which results from insertion of a conserved CHMP5 tyrosine residue (Tyr 182) at the core of LIP5NTD structure. Finally, mutation of Tyr 182 partially relieves the inhibition displayed by CHMP5. Together, these results suggest a novel mechanism of VPS4 regulation in metazoans, where CHMP5 functions as a negative allosteric switch to control LIP5-mediated stimulation of VPS4.« less

Binding of Substrates to the Central Pore of the Vps4 ATPase Is Autoinhibited by the Microtubule Interacting and Trafficking (MIT) Domain and Activated by MIT Interacting Motifs (MIMs).

PubMed

Han, Han; Monroe, Nicole; Votteler, Jörg; Shakya, Binita; Sundquist, Wesley I; Hill, Christopher P

2015-05-22

The endosomal sorting complexes required for transport (ESCRT) pathway drives reverse topology membrane fission events within multiple cellular pathways, including cytokinesis, multivesicular body biogenesis, repair of the plasma membrane, nuclear membrane vesicle formation, and HIV budding. The AAA ATPase Vps4 is recruited to membrane necks shortly before fission, where it catalyzes disassembly of the ESCRT-III lattice. The N-terminal Vps4 microtubule-interacting and trafficking (MIT) domains initially bind the C-terminal MIT-interacting motifs (MIMs) of ESCRT-III subunits, but it is unclear how the enzyme then remodels these substrates in response to ATP hydrolysis. Here, we report quantitative binding studies that demonstrate that residues from helix 5 of the Vps2p subunit of ESCRT-III bind to the central pore of an asymmetric Vps4p hexamer in a manner that is dependent upon the presence of flexible nucleotide analogs that can mimic multiple states in the ATP hydrolysis cycle. We also find that substrate engagement is autoinhibited by the Vps4p MIT domain and that this inhibition is relieved by binding of either Type 1 or Type 2 MIM elements, which bind the Vps4p MIT domain through different interfaces. These observations support the model that Vps4 substrates are initially recruited by an MIM-MIT interaction that activates the Vps4 central pore to engage substrates and generate force, thereby triggering ESCRT-III disassembly. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

CLPB mutations cause 3-methylglutaconic aciduria, progressive brain atrophy, intellectual disability, congenital neutropenia, cataracts, movement disorder.

PubMed

Wortmann, Saskia B; Ziętkiewicz, Szymon; Kousi, Maria; Szklarczyk, Radek; Haack, Tobias B; Gersting, Søren W; Muntau, Ania C; Rakovic, Aleksandar; Renkema, G Herma; Rodenburg, Richard J; Strom, Tim M; Meitinger, Thomas; Rubio-Gozalbo, M Estela; Chrusciel, Elzbieta; Distelmaier, Felix; Golzio, Christelle; Jansen, Joop H; van Karnebeek, Clara; Lillquist, Yolanda; Lücke, Thomas; Õunap, Katrin; Zordania, Riina; Yaplito-Lee, Joy; van Bokhoven, Hans; Spelbrink, Johannes N; Vaz, Frédéric M; Pras-Raves, Mia; Ploski, Rafal; Pronicka, Ewa; Klein, Christine; Willemsen, Michel A A P; de Brouwer, Arjan P M; Prokisch, Holger; Katsanis, Nicholas; Wevers, Ron A

2015-02-05

We studied a group of individuals with elevated urinary excretion of 3-methylglutaconic acid, neutropenia that can develop into leukemia, a neurological phenotype ranging from nonprogressive intellectual disability to a prenatal encephalopathy with progressive brain atrophy, movement disorder, cataracts, and early death. Exome sequencing of two unrelated individuals and subsequent Sanger sequencing of 16 individuals with an overlapping phenotype identified a total of 14 rare, predicted deleterious alleles in CLPB in 14 individuals from 9 unrelated families. CLPB encodes caseinolytic peptidase B homolog ClpB, a member of the AAA+ protein family. To evaluate the relevance of CLPB in the pathogenesis of this syndrome, we developed a zebrafish model and an in vitro assay to measure ATPase activity. Suppression of clpb in zebrafish embryos induced a central nervous system phenotype that was consistent with cerebellar and cerebral atrophy that could be rescued by wild-type, but not mutant, human CLPB mRNA. Consistent with these data, the loss-of-function effect of one of the identified variants (c.1222A>G [p.Arg408Gly]) was supported further by in vitro evidence with the mutant peptides abolishing ATPase function. Additionally, we show that CLPB interacts biochemically with ATP2A2, known to be involved in apoptotic processes in severe congenital neutropenia (SCN) 3 (Kostmann disease [caused by HAX1 mutations]). Taken together, mutations in CLPB define a syndrome with intellectual disability, congenital neutropenia, progressive brain atrophy, movement disorder, cataracts, and 3-methylglutaconic aciduria. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Binding of Substrates to the Central Pore of the Vps4 ATPase Is Autoinhibited by the Microtubule Interacting and Trafficking (MIT) Domain and Activated by MIT Interacting Motifs (MIMs)*

PubMed Central

Han, Han; Monroe, Nicole; Votteler, Jörg; Shakya, Binita; Sundquist, Wesley I.; Hill, Christopher P.

2015-01-01

The endosomal sorting complexes required for transport (ESCRT) pathway drives reverse topology membrane fission events within multiple cellular pathways, including cytokinesis, multivesicular body biogenesis, repair of the plasma membrane, nuclear membrane vesicle formation, and HIV budding. The AAA ATPase Vps4 is recruited to membrane necks shortly before fission, where it catalyzes disassembly of the ESCRT-III lattice. The N-terminal Vps4 microtubule-interacting and trafficking (MIT) domains initially bind the C-terminal MIT-interacting motifs (MIMs) of ESCRT-III subunits, but it is unclear how the enzyme then remodels these substrates in response to ATP hydrolysis. Here, we report quantitative binding studies that demonstrate that residues from helix 5 of the Vps2p subunit of ESCRT-III bind to the central pore of an asymmetric Vps4p hexamer in a manner that is dependent upon the presence of flexible nucleotide analogs that can mimic multiple states in the ATP hydrolysis cycle. We also find that substrate engagement is autoinhibited by the Vps4p MIT domain and that this inhibition is relieved by binding of either Type 1 or Type 2 MIM elements, which bind the Vps4p MIT domain through different interfaces. These observations support the model that Vps4 substrates are initially recruited by an MIM-MIT interaction that activates the Vps4 central pore to engage substrates and generate force, thereby triggering ESCRT-III disassembly. PMID:25833946

Meta-analysis of peak wall stress in ruptured, symptomatic and intact abdominal aortic aneurysms.

PubMed

Khosla, S; Morris, D R; Moxon, J V; Walker, P J; Gasser, T C; Golledge, J

2014-10-01

Abdominal aortic aneurysm (AAA) is an important cause of sudden death; however, there are currently incomplete means to predict the risk of AAA rupture. AAA peak wall stress (PWS) can be estimated using finite element analysis (FEA) methods from computed tomography (CT) scans. The question is whether AAA PWS can predict AAA rupture. The aim of this systematic review was to compare PWS in patients with ruptured and intact AAA. The MEDLINE database was searched on 25 May 2013. Case-control studies assessing PWS in asymptomatic intact, and acutely symptomatic or ruptured AAA from CT scans using FEA were included. Data were extracted independently. A random-effects model was used to calculate standard mean differences (SMDs) for PWS measurements. Nine studies assessing 348 individuals were identified and used in the meta-analysis. Results from 204 asymptomatic intact and 144 symptomatic or ruptured AAAs showed that PWS was significantly greater in the symptomatic/ ruptured AAAs compared with the asymptomatic intact AAAs (SMD 0·95, 95 per cent confidence interval 0·71 to 1·18; P < 0·001). The findings remained significant after adjustment for mean systolic blood pressure, standardized at 120 mmHg (SMD 0·68, 0·39 to 0·96; P < 0·001). Minimal heterogeneity between studies was noted (I(2)  = 0 per cent). This study suggests that PWS is greater in symptomatic or ruptured AAA than in asymptomatic intact AAA. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Visible Thrombolysis Acceleration of a Nanomachine Powered by Light-Driving F0F1-ATPase Motor

NASA Astrophysics Data System (ADS)

Duan, Xiaoxia; Liu, Lifeng; Jiang, Weijian; Yue, Jiachang

2015-05-01

We report on thrombolysis acceleration of a nanomachine powered by light-driving δ-subunit-free F0F1-ATPase motor. It is composed of a mechanical device, locating device, energy storage device, and propeller. The rotory δ-subunit-free F0F1-ATPase motor acts as a mechanical device, which was obtained by reconstructing an original chromatophore extracted from Rhodospirillum rubrum. We found that the bioactivity of the F0F1-ATPase motor improved greatly after reconstruction. The zeta potential of the nanomachine is about -23.4 mV. Cytotoxicity induced by the nanomachine was measured using cell counting kit (CCK)-8 assay. The A549 cells incubated with different fractional concentrations of the nanomachine within 48 h did not show obvious cytotoxicity. The locating device helps the nanomachine bind to the thrombi. Energy was easily stored by exposing the nanomachine to 600-nm-wavelength irradiation, which promoted activity of the motor. The rotation of the long propeller accelerated thrombolysis of a blood clot in vitro in the presence of urokinase (UK). This result was based on visual inspection and confirmed by a series of tests.

Effects of zearalenone on calcium homeostasis of splenic lymphocytes of chickens in vitro.

PubMed

Wang, Y C; Deng, J L; Xu, S W; Peng, X; Zuo, Z C; Cui, H M; Wang, Y; Ren, Z H

2012-08-01

Zearalenone (ZEA) is an estrogenic mycotoxin. It is produced by several Fusarium species and can contaminate food and feed. To investigate the role of calcium homeostasis in ZEA-induced toxicity of poultry and elucidate its cytotoxic mechanism, splenic lymphocytes isolated from chickens were exposed to ZEA (0-25 μg/mL) for 48 h. The intracellular calcium concentration ([Ca2+]i), pH, calmodulin (CaM) mRNA levels, and Na+/K+-ATPase activities and Ca2+-ATPase activities were detected by the fluorescent dyes Fluo-3/AM and BCECF/AM, quantitative real-time PCR, and chromatometry. Supernatant CaM concentrations were simultaneously detected by ELISA. As the ZEA exposure concentration increased, the [Ca2+]i and CaM mRNA levels gradually increased, while intracellular pH, CaM concentrations of supernatants, and intracellular Na+,K+-ATPase and Ca2+-ATPase activities gradually decreased in a dose-dependent manner. There were significant differences (P<0.05 or P<0.01) between the treatment groups and the control group. These results indicate that ZEA cytotoxicity arises by causing an imbalance in calcium homeostasis and intracellular acidification in lymphocytes.

Intervisceral artery origins in patients with abdominal aortic aneurysmal disease; evidence for systemic vascular remodelling.

PubMed

Bailey, Damian M; Evans, Tom G; Thomas, Kate Gower; White, Richard D; Twine, Chistopher P; Lewis, Michael H; Williams, Ian M

2016-08-01

What is the central question of this study? To what extent focal abdominal aortic aneurysmal (AAA) disease is associated with systemic remodelling of the vascular tree remains unknown. The present study examined whether anatomical differences exist between distances of the intervisceral artery origins and AAA location/size in patients with disease compared with healthy patients. What is the main finding and its importance? Intervisceral artery distances were shown to be consistently greater in AAA patients, highlighting the systemic nature of AAA disease that extends proximally to the abdominal aorta and its branches. The anatomical description of the natural variation in visceral artery origins has implications for the design of stent grafts and planning complex open aortic surgery. The initial histopathology of abdominal aortic aneurysmal (AAA) disease is atherosclerotic, later diverting towards a distinctive dilating rather than occlusive aortic phenotype. To what extent focal AAA disease is associated with systemic remodelling of the vascular tree remains unknown. The present study examined whether anatomical differences exist between the intervisceral artery origins and AAA location/size in patients with AAA disease (AAA+) relative to those without (AAA-). Preoperative contrast-enhanced computerized tomograms were reviewed in 90 consecutive AAA+ patients scheduled for open repair who underwent an infrarenal (n = 45), suprarenal (n = 26) or supracoeliac clamp (n = 19). These were compared with 39 age-matched AAA- control patients. Craniocaudal measurements were recorded from the distal origin of the coeliac artery to the superior mesenteric artery and from the origin of the superior mesenteric artery to both renal artery origins. Serial blood samples were obtained for estimation of the glomerular filtration rate before and after surgery. Intervisceral artery origins were shown to be consistently greater in AAA+ patients (P < 0.05 versus AAA-), although unrelated to AAA diameter (P > 0.05). Postoperative renal function became progressively more impaired the more proximal the clamp placement (estimated glomerular filtration rate for supracoeliac < suprarenal < infrarenal clamps, P < 0.05). These findings highlight the systemic nature of AAA disease that extends proximally to the abdominal aorta and its branches. The anatomical description of the natural variation in visceral artery origins has implications for the design of stent grafts and planning complex open aortic surgery. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Biomarkers for AAA: Encouraging steps but clinical relevance still to be delivered.

PubMed

Htun, Nay Min; Peter, Karlheinz

2014-10-01

Potential biomarkers have been investigated using proteomic studies in a variety of diseases. Some biomarkers have central roles in both diagnosis and monitoring of various disorders in clinical medicine, such as troponins, brain natriuretic peptide, and C-reactive protein. Although several biomarkers have been suggested in human abdominal aortic aneurysm (AAA), reliable markers have been lacking. In this issue, Moxon et al. [Proteomics Clin Appl. 2014, 8, 762-772] undertook a broad and systematic proteomic approach toward identification of biomarkers in a commonly used AAA mouse model (AAA created by angiotensin-II infusion). In this mouse model, apolipoprotein C1 and matrix metalloproteinase-9 were identified as novel biomarkers of stable AAA. This finding represents an important step forward, toward a clinically relevant role of biomarkers in AAA. This also encourages for further studies toward the identification of biomarkers (or their combinations) that can predict AAA progression and rupture, which would represent a major progress in AAA management and would establish an AAA biomarker as a much anticipated clinical tool. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reconsidering gender relative to risk of rupture in the contemporary management of abdominal aortic aneurysms.

PubMed

Skibba, Afshin A; Evans, James R; Hopkins, Steven P; Yoon, H Richard; Katras, Tony; Kalbfleisch, John H; Rush, Daniel S

2015-12-01

Abdominal aortic aneurysms (AAAs) may rupture at smaller diameters in women than in men, and women may be at higher risk and have poorer outcomes in elective and emergent interventions because of age and comorbidities. Practice guidelines recommending elective AAA repair at >5.5 cm are gender neutral and may not adequately reflect increased risks in women or the potential advantages of elective lower risk endovascular procedures. Patients with a diagnosis of AAA discharged from a single referral hospital during a 14-year period were identified for retrospective analysis. A total of 2121 patients with AAAs were studied, 499 women (23.5%) and 1622 men (76.5%). Women were older and had a greater incidence of hypertension, smoking, chronic obstructive pulmonary disease, dyslipidemia, and renal insufficiency. Intact AAAs in 467 women had a mean diameter of 4.4 ± 1.3 cm compared with 1538 men at 5.0 ± 1.4 cm (P < .01). The ruptured AAAs in 32 women (6.4%) had a mean diameter of 6.1 ± 1.5 cm compared with 84 men (5.2%) at 7.7 ± 1.9 cm (P < .01). Women had a twofold increased frequency of AAA rupture than men at all size intervals (P < .01). The frequency of ruptured AAAs <5.5 cm among 10 of 32 women with ruptured AAAs was 31.3%; among 7 of 84 men with ruptured AAAs, it was 8.3% (P < .01). The frequency of ruptured AAAs <5.5 cm in all 383 women with AAAs <5.5 cm was 2.6%; in 1042 men, it was 0.6% (P < .01). Of the 1211 AAA repairs, 574 (47.4%) were open aneurysm repair (OAR) and 637 (52.6%) were endovascular aneurysm repair (EVAR). Mortality after elective OAR in 475 patients of both sexes was 5.1%; for EVAR in 676 patients, mortality was 1.6% (P < .01). No differences in mortality with respect to OAR or EVAR were found between the female and male cohorts in either intact or ruptured AAAs. Women with AAAs are older and have a higher frequency of cardiovascular risk factors than men. Women rupture AAAs with a greater frequency than men at all size intervals and have a fourfold increased frequency of rupture at <5.5 cm. No differences in surgical mortality between women and men were found. Current practice guidelines for elective AAA operative intervention should be reconsidered and stratified by gender. Published by Elsevier Inc.

Variations in Abdominal Aortic Aneurysm Care: A Report From the International Consortium of Vascular Registries

PubMed Central

Sedrakyan, Art; Mao, Jialin; Venermo, Maarit; Faizer, Rumi; Debus, Sebastian; Behrendt, Christian-Alexander; Scali, Salvatore; Altreuther, Martin; Schermerhorn, Marc; Beiles, Barry; Szeberin, Zoltan; Eldrup, Nikolaj; Danielsson, Gudmundur; Thomson, Ian; Wigger, Pius; Björck, Martin; Cronenwett, Jack L.; Mani, Kevin

2016-01-01

Background: This project by the ICVR (International Consortium of Vascular Registries), a collaboration of 11 vascular surgical quality registries, was designed to evaluate international variation in the contemporary management of abdominal aortic aneurysm (AAA) with relation to recommended treatment guidelines from the Society for Vascular Surgery and the European Society for Vascular Surgery. Methods: Registry data for open and endovascular AAA repair (EVAR) during 2010 to 2013 were collected from 11 countries. Variations in patient selection and treatment were compared across countries and across centers within countries. Results: Among 51 153 patients, 86% were treated for intact AAA (iAAA) and 14% for ruptured AAA. Women constituted 18% of the entire cohort (range, 12% in Switzerland–21% in the United States; P<0.01). Intact AAAs were repaired at diameters smaller than recommended by guidelines in 31% of men (<5.5 cm; range, 6% in Iceland–41% in Germany; P<0.01) and 12% of women with iAAA (<5 cm; range, 0% in Iceland–16% in the United States; P<0.01). Overall, use of EVAR for iAAA varied from 28% in Hungary to 79% in the United States (P<0.01) and for ruptured AAA from 5% in Denmark to 52% in the United States (P<0.01). In addition to the between-country variations, significant variations were present between centers in each country in terms of EVAR use and rate of small AAA repair. Countries that more frequently treated small AAAs tended to use EVAR more frequently (trend: correlation coefficient, 0.51; P=0.14). Octogenarians made up 23% of all patients, ranging from 12% in Hungary to 29% in Australia (P<0.01). In countries with a fee-for-service reimbursement system (Australia, Germany, Switzerland, and the United States), the proportions of small AAA (33%) and octogenarians undergoing iAAA repair (25%) were higher compared with countries with a population-based reimbursement model (small AAA repair, 16%; octogenarians, 18%; P<0.01). In general, center-level variation within countries in the management of AAA was as important as variation between countries. Conclusions: Despite homogeneous guidelines from professional societies, significant variation exists in the management of AAA, most notably for iAAA diameter at repair, use of EVAR, and the treatment of elderly patients. ICVR provides an opportunity to study treatment variation across countries and to encourage optimal practice by sharing these results. PMID:27784712

Octogenarians Undergoing Open Repair Have Higher Mortality Compared with Fenestrated Endovascular Repair of Intact Abdominal Aortic Aneurysms Involving the Visceral Vessels.

PubMed

Locham, Satinderjit; Faateh, Muhammad; Dakour-Aridi, Hanaa; Nejim, Besma; Malas, Mahmoud

2018-04-18

Prior studies have shown that octogenarians have a higher risk of mortality than nonoctogenarians undergoing open aneurysm repair (OAR) and endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA). Fenestrated endovascular aneurysm repair (F-EVAR) was approved by the Food and Drug Administration (FDA) in 2012 and has been used as a less invasive approach to treat patients with suboptimal neck anatomy with favorable outcomes compared with traditional OAR. The aim of the study is to compare 30-day outcomes of F-EVAR versus OAR in octogenarians undergoing repair of AAA involving the visceral vessels in the United States. All patients with postoperative diagnosis of nonruptured AAA repair were identified in the National Surgical Quality Improvement Program database (2006-2015). Univariate and multivariate analyses were implemented to examine 30-day morbidity and mortality adjusting for patient demographics and comorbidities. A total of 548 octogenarians underwent repair of nonruptured AAA involving the visceral vessels, of which 242 (44%) were F-EVARs, and 306 (56%) were OARs. Octogenarians undergoing F-EVAR were on average 1-year older (median age [interquartile range]: 83 [82, 86] versus 82 [81, 85], P = 0.004) and more likely to be male (82% vs. 64%, P < 0.001) compared with OAR. Prevalence of diabetes (13% vs. 6%, P = 0.005) and progressive renal failure (57% vs. 47%, P = 0.03) was also higher in patients undergoing F-EVAR compared with OAR. Thirty-day postoperative mortality was higher after OAR (8.5% vs. 4.1%, P = 0.04). Secondary outcomes including cardiopulmonary (27.1% vs. 5.8%, P < 0.001) and renal injury (10.8% vs. 2.1%, P < 0.001) were also significantly higher in OAR compared with F-EVAR. After adjusting for patients' demographics and comorbidities, OAR had almost 4-fold increased risk of 30-day postoperative mortality compared with F-EVAR (odds ratio [95% confidence interval]: 3.90 [1.48-10.31], P = 0.006). In this large national cohort of octogenarians undergoing repair for complex AAA's, we showed that F-EVAR is associated with significantly lower postoperative morbidity and mortality than open repair. One of the main limitations of the study is the lack of anatomical data. However, despite that, our findings support the shifting paradigm toward minimally invasive approach in this frail population for treatment of complex AAA's. Further studies are needed to evaluate the long-term benefit of any repair in octogenarians. Copyright © 2018 Elsevier Inc. All rights reserved.

Differential gene expression in human abdominal aortic aneurysm and aortic occlusive disease

PubMed Central

Moran, Corey S.; Schreurs, Charlotte; Lindeman, Jan H. N.; Walker, Philip J.; Nataatmadja, Maria; West, Malcolm; Holdt, Lesca M.; Hinterseher, Irene; Pilarsky, Christian; Golledge, Jonathan

2015-01-01

Abdominal aortic aneurysm (AAA) and aortic occlusive disease (AOD) represent common causes of morbidity and mortality in elderly populations which were previously believed to have common aetiologies. The aim of this study was to assess the gene expression in human AAA and AOD. We performed microarrays using aortic specimen obtained from 20 patients with small AAAs (≤ 55mm), 29 patients with large AAAs (> 55mm), 9 AOD patients, and 10 control aortic specimens obtained from organ donors. Some differentially expressed genes were validated by quantitative-PCR (qRT-PCR)/immunohistochemistry. We identified 840 and 1,014 differentially expressed genes in small and large AAAs, respectively. Immune-related pathways including cytokine-cytokine receptor interaction and T-cell-receptor signalling were upregulated in both small and large AAAs. Examples of validated genes included CTLA4 (2.01-fold upregulated in small AAA, P = 0.002), NKTR (2.37-and 2.66-fold upregulated in small and large AAA with P = 0.041 and P = 0.015, respectively), and CD8A (2.57-fold upregulated in large AAA, P = 0.004). 1,765 differentially expressed genes were identified in AOD. Pathways upregulated in AOD included metabolic and oxidative phosphorylation categories. The UCP2 gene was downregulated in AOD (3.73-fold downregulated, validated P = 0.017). In conclusion, the AAA and AOD transcriptomes were very different suggesting that AAA and AOD have distinct pathogenic mechanisms. PMID:25944698

Predictors of physician confidence to diagnose pneumonia and determine illness severity in ventilated patients. Australian and New Zealand practice in intensive care (ANZPIC II).

PubMed

Boots, R J; Lipman, J; Bellomo, R; Stephens, D; Heller, R E

2005-02-01

The manner in which elements of clinical history, physical examination and investigations influence subjectively assessed illness severity and outcome prediction is poorly understood. This study investigates the relationship between clinician and objectively assessed illness severity and the factors influencing clinician's diagnostic confidence and illness severity rating for ventilated patients with suspected pneumonia in the intensive care unit (ICU). A prospective study of fourteen ICUs included all ventilated admissions with a clinical diagnosis of pneumonia. Data collection included pneumonia type - community-acquired (CAP), hospital-acquired (HAP) and ventilator-associated (VAP), clinician determined illness severity (CDIS), diagnostic methods, clinical diagnostic confidence (CDC), microbiological isolates and antibiotic use. For 476 episodes of pneumonia (48% CAP, 24% HAP, 28% VAP), CDC was greatest for CAP (64% CAP, 50% HAP and 49% VAP, P<0.01) or when pneumonia was considered "life-threatening" (84% high CDC, 13% medium CDC and 3% low CDC, P<0. 001). "Life-threatening" pneumonia was predicted by worsening gas exchange (OR 4.8, CI 95% 2.3-10.2, P<0.001), clinical signs of consolidation (OR 2.0, CI 95% 1.2-3.2, P<0.01) and the Sepsis-Related Organ Failure Assessment (SOFA) Score (OR 1.1, CI 95% 1.1-1.2, P<0.001). Diagnostic confidence increased with CDIS (OR 16.3, CI 95% 8.4-31.4, P<0.001), definite pathogen isolation (OR 3.3, CI 95% 2.0-5.6) and clinical signs of consolidation (OR 2.1, CI 95% 1.3-3.3, P=0.001). Although the CDIS, SOFA Score and the Simplified Acute Physiologic Score (SAPS II) were all associated with mortality, the SAPS II Score was the best predictor of mortality (P = 0. 02). Diagnostic confidence for pneumonia is moderate but increases with more classical presentations. A small set of clinical parameters influence subjective assessment. Objective assessment using SAPS II Scoring is a better predictor of mortality.

Computational Growth and Remodeling of Abdominal Aortic Aneurysms Constrained by the Spine

PubMed Central

Farsad, Mehdi; Zeinali-Davarani, Shahrokh; Choi, Jongeun; Baek, Seungik

2015-01-01

Abdominal aortic aneurysms (AAAs) evolve over time, and the vertebral column, which acts as an external barrier, affects their biomechanical properties. Mechanical interaction between AAAs and the spine is believed to alter the geometry, wall stress distribution, and blood flow, although the degree of this interaction may depend on AAAs specific configurations. In this study, we use a growth and remodeling (G&R) model, which is able to trace alterations of the geometry, thus allowing us to computationally investigate the effect of the spine for progression of the AAA. Medical image-based geometry of an aorta is constructed along with the spine surface, which is incorporated into the computational model as a cloud of points. The G&R simulation is initiated by local elastin degradation with different spatial distributions. The AAA–spine interaction is accounted for using a penalty method when the AAA surface meets the spine surface. The simulation results show that, while the radial growth of the AAA wall is prevented on the posterior side due to the spine acting as a constraint, the AAA expands faster on the anterior side, leading to higher curvature and asymmetry in the AAA configuration compared to the simulation excluding the spine. Accordingly, the AAA wall stress increases on the lateral, posterolateral, and the shoulder regions of the anterior side due to the AAA–spine contact. In addition, more collagen is deposited on the regions with a maximum diameter. We show that an image-based computational G&R model not only enhances the prediction of the geometry, wall stress, and strength distributions of AAAs but also provides a framework to account for the interactions between an enlarging AAA and the spine for a better rupture potential assessment and management of AAA patients. PMID:26158885

Prior Radiological Investigations in 65-Year-Old Men Screened for AAA.

PubMed

Meecham, Lewis; Summerour, Virginia; Hobbs, Simon; Newman, Jeremy; Wall, Michael L

2018-05-01

The National Health Service abdominal aortic aneurysm screening programme (NAAASP) is now fully operational. Those who have previously been formally investigated for abdominal aortic aneurysm (AAA) are excluded; however, many patients undergo radiological investigation of the abdomen for other reasons. Such practices may find incidental AAA which may be eroding the performance of the NAAASP. We investigated the rates of preinvestigation before invitation to screening in our local AAA screening programme. Electronic patient records were retrospectively reviewed for all patients called between March 2013 and February 2016 in 1 local AAA screening programme. Their records were interrogated to identify any abdominal imaging within 5 years of their invitation to screening. Two thousand six hundred thirty-eight men were invited for screening; of these, 563 (21.3%) had been "prescreened". Median time between prescreening and screening was 19 months (0-60 months). Ultrasound abdomen was the most prevalent at 248 (44.0%). Two thousand two hundred forty-three (85.0%) men attended screening, and 6 (0.27%) were excluded for known AAA. Prevalence of AAA was 1.8% (n = 41). Of these, 15 (36.6%) had prior investigation with 6 (40.0%) having AAA diagnosed. Therefore, 9 (22.0%) had potential missed AAA on "prescreening" (mean diameter 35 mm [30-45], mean time lapse between investigation and screening 21.1 months [1-49]). Incidence of missed aneurysm in the "prescreened" cohort was 1.6% (9/563). Large numbers of men invited for AAA screening have undergone preinvestigation of their abdominal aorta, with 60% of the present AAA being missed. Reliance on incidental detection of AAA would leave many patients undiagnosed in the community-at risk of future rupture. Copyright © 2018 Elsevier Inc. All rights reserved.

Increased galectin-3 levels are associated with abdominal aortic aneurysm progression and inhibition of galectin-3 decreases elastase-induced AAA development.

PubMed

Fernandez-García, Carlos-Ernesto; Tarin, Carlos; Roldan-Montero, Raquel; Martinez-Lopez, Diego; Torres-Fonseca, Monica; Lindhot, Jes S; Vega de Ceniga, Melina; Egido, Jesus; Lopez-Andres, Natalia; Blanco-Colio, Luis-Miguel; Martín-Ventura, Jose-Luis

2017-11-15

Abdominal aortic aneurysm (AAA) evolution is unpredictable and no specific treatment exists for AAA, except surgery to prevent aortic rupture. Galectin-3 has been previously associated with CVD, but its potential role in AAA has not been addressed. Galectin-3 levels were increased in the plasma of AAA patients ( n =225) compared with the control group ( n =100). In addition, galectin-3 concentrations were associated with the need for surgical repair, independently of potential confounding factors. Galectin-3 mRNA and protein expression were increased in human AAA samples compared with healthy aortas. Experimental AAA in mice was induced via aortic elastase perfusion. Mice were treated intravenously with the galectin-3 inhibitor modified citrus pectin (MCP, 10 mg/kg, every other day) or saline. Similar to humans, galectin-3 serum and aortic mRNA levels were also increased in elastase-induced AAA mice compared with control mice. Mice treated with MCP showed decreased aortic dilation, as well as elastin degradation, vascular smooth muscle cell (VSMC) loss, and macrophage content at day 14 postelastase perfusion compared with control mice. The underlying mechanism(s) of the protective effect of MCP was associated with a decrease in galectin-3 and cytokine (mainly CCL5) mRNA and protein expression. Interestingly, galectin-3 induced CCL5 expression by a mechanism involving STAT3 activation in VSMC. Accordingly, MCP treatment decreased STAT3 phosphorylation in elastase-induced AAA. In conclusion, increased galectin-3 levels are associated with AAA progression, while galectin-3 inhibition decreased experimental AAA development. Our data suggest the potential role of galectin-3 as a therapeutic target in AAA. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Epidemiology and outcome of aortic aneurysms in Hong Kong.

PubMed

Cheng, Stephen W K; Ting, Albert C W; Tsang, Simon H Y

2003-02-01

The objective of this study was to determine epidemiology and mortality statistics for abdominal aortic aneurysms (AAAs) in Hong Kong. Data from three sources were obtained and analyzed: (1) Hong Kong Hospital Authority discharge statistics for 1999 and 2000; (2) a survey on aortic aneurysms in public hospitals conducted by the Working Group of Vascular Surgery; and (3) the Department of Surgery, University of Hong Kong Medical Center aortic aneurysm database. The disease pattern, distribution, and operative mortality were determined. The annual incidence of AAA in Hong Kong is 13.7 per 100,000 population and 105 per 100,000 for those aged 65 and above. About 10% of the AAAs that presented were ruptured. The mean age of the AAA patients was 74 years, with 84% of them over age 65. The operative repair rate for AAAs was low, being only 8% for intact aneurysms and 54% for ruptured ones. Overall, 45% of all aneurysm repairs were performed for a ruptured AAA. There is diverse practice between major vascular centers and smaller regional hospitals. The territory-wide operative mortality rates for intact and ruptured aneurysms were 10% (range 4-24%) and 70% (range 38--100%), respectively. There was no gender bias in the rupture and operative rates. The overall mortality was 17% for intact AAAs and 78% for ruptured AAAs. The average length of hospital stay was 19 days for elective AAA surgery and 13 days for ruptured AAAs. The number of operations in high-volume centers is increasing with a concomitant decrease in operative mortality. There are no definitive data to indicate that the incidence of AAAs is rising, but a trend toward an increasing number of operations in referral centers is noted. The low repair rates for intact AAAs and the high proportion of repairs for ruptured aneurysms suggest that AAAs are undertreated in Hong Kong.

Mitochondrial AAA proteases--towards a molecular understanding of membrane-bound proteolytic machines.

PubMed

Gerdes, Florian; Tatsuta, Takashi; Langer, Thomas

2012-01-01

Mitochondrial AAA proteases play an important role in the maintenance of mitochondrial proteostasis. They regulate and promote biogenesis of mitochondrial proteins by acting as processing enzymes and ensuring the selective turnover of misfolded proteins. Impairment of AAA proteases causes pleiotropic defects in various organisms including neurodegeneration in humans. AAA proteases comprise ring-like hexameric complexes in the mitochondrial inner membrane and are functionally conserved from yeast to man, but variations are evident in the subunit composition of orthologous enzymes. Recent structural and biochemical studies revealed how AAA proteases degrade their substrates in an ATP dependent manner. Intersubunit coordination of the ATP hydrolysis leads to an ordered ATP hydrolysis within the AAA ring, which ensures efficient substrate dislocation from the membrane and translocation to the proteolytic chamber. In this review, we summarize recent findings on the molecular mechanisms underlying the versatile functions of mitochondrial AAA proteases and their relevance to those of the other AAA+ machines. Copyright © 2011 Elsevier B.V. All rights reserved.

The test characteristics of head circumference measurements for pathology associated with head enlargement: a retrospective cohort study

PubMed Central

2012-01-01

Background The test characteristics of head circumference (HC) measurement percentile criteria for the identification of previously undetected pathology associated with head enlargement in primary care are unknown. Methods Electronic patient records were reviewed to identify children age 3 days to 3 years with new diagnoses of intracranial expansive conditions (IEC) and metabolic and genetic conditions associated with macrocephaly (MGCM). We tested the following HC percentile threshold criteria: ever above the 95th, 97th, or 99.6th percentile and ever crossing 2, 4, or 6 increasing major percentile lines. The Centers for Disease Control and World Health Organization growth curves were used, as well as the primary care network (PCN) curves previously derived from this cohort. Results Among 74,428 subjects, 85 (0.11%) had a new diagnosis of IEC (n = 56) or MGCM (n = 29), and between these 2 groups, 24 received intervention. The 99.6th percentile of the PCN curve was the only threshold with a PPV over 1% (PPV 1.8%); the sensitivity of this threshold was only 15%. Test characteristics for the 95th percentiles were: sensitivity (CDC: 46%; WHO: 55%; PCN: 40%), positive predictive value (PPV: CDC: 0.3%; WHO: 0.3%; PCN: 0.4%), and likelihood ratios positive (LR+: CDC: 2.8; WHO: 2.2; PCN: 3.9). Test characteristics for the 97th percentiles were: sensitivity (CDC: 40%; WHO: 48%; PCN: 34%), PPV (CDC: 0.4%; WHO: 0.3%; PCN: 0.6%), and LR+ (CDC: 3.6; WHO: 2.7; PCN: 5.6). Test characteristics for crossing 2 increasing major percentile lines were: sensitivity (CDC: 60%; WHO: 40%; PCN: 31%), PPV (CDC: 0.2%; WHO: 0.1%; PCN: 0.2%), and LR+ (CDC: 1.3; WHO: 1.1; PCN: 1.5). Conclusions Commonly used HC percentile thresholds had low sensitivity and low positive predictive value for diagnosing new pathology associated with head enlargement in children in a primary care network. PMID:22269214

Adventitial adipogenic degeneration is an unidentified contributor to aortic wall weakening in the abdominal aortic aneurysm.

PubMed

Doderer, Stefan A; Gäbel, Gabor; Kokje, Vivianne B C; Northoff, Bernd H; Holdt, Lesca M; Hamming, Jaap F; Lindeman, Jan H N

2018-06-01

The processes driving human abdominal aortic aneurysm (AAA) progression are not fully understood. Although antiinflammatory and proteolytic strategies effectively quench aneurysm progression in preclinical models, so far all clinical interventions failed. These observations hint at an incomplete understanding of the processes involved in AAA progression and rupture. Interestingly, strong clinical and molecular associations exist between popliteal artery aneurysms (PAAs) and AAAs; however, PAAs have an extremely low propensity to rupture. We thus reasoned that differences between these aneurysms may provide clues toward (auxiliary) processes involved in AAA-related wall debilitation. A better understanding of the pathophysiologic processes driving AAA growth can contribute to pharmaceutical treatments in the future. Aneurysmal wall samples were collected during open elective and emergency repair. Control perirenal aorta was obtained during kidney transplantation, and reference popliteal tissue obtained from the anatomy department. This study incorporates various techniques including (immuno)histochemistry, Western Blot, quantitative polymerase chain reaction, microarray, and cell culture. Histologic evaluation of AAAs, PAAs, and control aorta shows extensive medial (PAA) and transmural fibrosis (AAA), and reveals abundant adventitial adipocytes aggregates as an exclusive phenomenon of AAAs (P < .001). Quantitative polymerase chain reaction, immunohistochemistry, Western blotting, and microarray analysis showed enrichment of adipogenic mediators (C/EBP family P = .027; KLF5 P < .000; and peroxisome proliferator activated receptor-γ, P = .032) in AAA tissue. In vitro differentiation tests indicated a sharply increased adipogenic potential of AAA adventitial mesenchymal cells (P < .0001). Observed enrichment of adipocyte-related genes and pathways in ruptured AAA (P < .0003) supports an association between the extent of fatty degeneration and rupture. This translational study identifies extensive adventitial fatty degeneration as an ignored and distinctive feature of AAA disease. Enrichment of adipocyte genesis and adipocyte-related genes in ruptured AAA point to an association between the extent of fatty degeneration and rupture. This observation may (partly) explain the failure of medical therapy and could provide a lead for pharmaceutical alleviation of AAA progression. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Science, Society, and Social Networking

NASA Astrophysics Data System (ADS)

White, K. S.; Lohwater, T.

2009-12-01

The increased use of social networking is changing the way that scientific societies interact with their members and others. The American Association for the Advancement of Science (AAAS) uses a variety of online networks to engage its members and the broader scientific community. AAAS members and non-members can interact with AAAS staff and each other on AAAS sites on Facebook, YouTube, and Twitter, as well as blogs and forums on the AAAS website (www.aaas.org). These tools allow scientists to more readily become engaged in policy by providing information on current science policy topics as well as methods of involvement. For example, members and the public can comment on policy-relevant stories from Science magazine’s ScienceInsider blog, download a weekly policy podcast, receive a weekly email update of policy issues affecting the scientific community, or watch a congressional hearing from their computer. AAAS resource websites and outreach programs, including Communicating Science (www.aaas.org/communicatingscience), Working with Congress (www.aaas.org/spp/cstc/) and Science Careers (http://sciencecareers.sciencemag.org) also provide tools for scientists to become more personally engaged in communicating their findings and involved in the policy process.

APC-PCI complex levels for screening of AAA in patients with peripheral atherosclerosis.

PubMed

Zarrouk, Moncef; Keshavarz, Kave; Lindblad, Bengt; Gottsäter, Anders

2013-11-01

To evaluate the use of activated protein C-protein C inhibitor (APC-PCI) complex levels for detection of abdominal aortic aneurysm (AAA) in patients with peripheral atherosclerotic disease (PAD). APC-PCI levels and aortic diameter evaluated in 511 PAD patients without previously known AAA followed-up concerning survival for 4.8(0.5) years. AAA was found in 13% of patients. Aortic diameter correlated (r = 0.138; p = 0.002) with APC-PCI levels which were higher (0.40[0.45] vs. 0.30[0.49] μg/l; p = 0.004) in patients with AAA. This difference persisted in multivariate analysis (p = 0.029). A threshold value of APC-PCI ≥0.15 μg/L showed a specificity of 11%, a sensitivity of 97% and a negative predictive value of 96% for an AAA diagnosis. APC-PCI levels were higher in patients with AAA, and showed high sensitivity but low specificity for the diagnosis and can therefore not be considered as a screening tool in PAD patients. An AAA prevalence of 13% in patients with PAD indicates a need for AAA screening within this population.

Abdominal aortic aneurysm and the association with serum levels of Homocysteine, vitamins B6, B12 and Folate

PubMed Central

Lindqvist, Markus; Hellström, Anders; Henriksson, Anders E

2012-01-01

Previous investigations have shown hyperhomocysteinemi in patients with abdominal aortic aneurysm (AAA). In the present study we evaluated the circulating level of homocysteine (Hcy) in relation to renal function, vitamins B6, B12 and folate status in AAA patients with special regard to aneurysm size, and rupture. Hcy, Creatinine, B6, B12 and folate were measured in 119 patients with AAA and 36 controls without aneurysm matched by age, gender and smoking habit. As expected there was a weak correlation between Hcy and vitamins B6, B12 or folate. We found similar levels of Hcy, B6 and folic acid in patients with nonruptured AAA compared to the control group matched by age, gender and smoking habit. There was no correlation between maximum diameter of the nonruptured AAA (n=78) and Hcy, B6 or folate. However, the present study shows a significant inverse correlation between maximum diameter of the nonruptured AAA (n=78) and B12 (r = -0.304, p=0.007) with significant higher levels in small AAA compared to large AAA. In conclusion, Hcy does not seem to be a useful biomarker in AAA disease. The unexpected finding of B12 levels correlating to aneurysm diameter warrants urgent further investigation of B12 supplement to prevent progression of small AAA. PMID:23173106

Abdominal aortic aneurysm and the association with serum levels of Homocysteine, vitamins B6, B12 and Folate.

PubMed

Lindqvist, Markus; Hellström, Anders; Henriksson, Anders E

2012-01-01

Previous investigations have shown hyperhomocysteinemi in patients with abdominal aortic aneurysm (AAA). In the present study we evaluated the circulating level of homocysteine (Hcy) in relation to renal function, vitamins B6, B12 and folate status in AAA patients with special regard to aneurysm size, and rupture. Hcy, Creatinine, B6, B12 and folate were measured in 119 patients with AAA and 36 controls without aneurysm matched by age, gender and smoking habit. As expected there was a weak correlation between Hcy and vitamins B6, B12 or folate. We found similar levels of Hcy, B6 and folic acid in patients with nonruptured AAA compared to the control group matched by age, gender and smoking habit. There was no correlation between maximum diameter of the nonruptured AAA (n=78) and Hcy, B6 or folate. However, the present study shows a significant inverse correlation between maximum diameter of the nonruptured AAA (n=78) and B12 (r = -0.304, p=0.007) with significant higher levels in small AAA compared to large AAA. In conclusion, Hcy does not seem to be a useful biomarker in AAA disease. The unexpected finding of B12 levels correlating to aneurysm diameter warrants urgent further investigation of B12 supplement to prevent progression of small AAA.

Chronic Liver Disease and American Indians/Alaska Natives

MedlinePlus

... www.cdc.gov/nchs/nhis/shs/tables.htm Death Rate Cancer Death Rates per 100,000 – Men (2009-2013) Cancer: ... Counties 4.8 7.8 0.6 Cancer Death Rates per 100,000 – Women (2009-2013) Cancer: ...

Abdominal aortic aneurysms: pre- and post-procedural imaging.

PubMed

Hallett, Richard L; Ullery, Brant W; Fleischmann, Dominik

2018-05-01

Abdominal aortic aneurysm (AAA) is a relatively common, potentially life-threatening disorder. Rupture of AAA is potentially catastrophic with high mortality. Intervention for AAA is indicated when the aneurysm reaches 5.0-5.5 cm or more, when symptomatic, or when increasing in size > 10 mm/year. AAA can be accurately assessed by cross-sectional imaging including computed tomography angiography and magnetic resonance angiography. Current options for intervention in AAA patients include open surgery and endovascular aneurysm repair (EVAR), with EVAR becoming more prevalent over time. Cross-sectional imaging plays a crucial role in AAA surveillance, pre-procedural assessment, and post-EVAR management. This paper will discuss the current role of imaging in the assessment of AAA patients prior to intervention, in evaluation of procedural complications, and in long-term follow-up of EVAR patients.

Time trends in hospital admissions and mortality due to abdominal aortic aneurysms in France, 2002-2013.

PubMed

Robert, M; Juillière, Y; Gabet, A; Kownator, S; Olié, V

2017-05-01

Abdominal aortic aneurysms (AAA) are serious disease with a high fatality rate but recent epidemiologic data showed a decrease of AAA mortality. Our objective was to estimate, in France, the hospitalization, inhospital mortality and mortality rates due to AAA and to analyze their trends over time. Hospitalization data were extracted from the hospital discharge summaries in the national database between 2002 and 2013. The analysis covered all patients hospitalized for AAA as a principal diagnosis. During the same period, all death certificates mentioning AAA as an initial cause of death were included in the study. Crude and standardized rates were calculated according to age and sex. Poisson regression was used to analyze the average annual percent change. In 2013, there were 8853 patients hospitalized for AAA in France (7986 unruptured and 867 ruptured). Between 2002 and 2013, the rate of patients hospitalized for unruptured AAA decreased slightly in men (-5.0%) but increased in women (+5.2%). By contrast, the rate of patients hospitalized for ruptured AAA has decreased by >20% in men and women. The proportion of endovascular treatment of unruptured AAA rose from <10% in 2005 to 35% in women and 40% in men in 2013. In 2013, 939 deaths from AAA were recorded. Mortality for this disease declined significantly from 2002 to 2013 in men and women. The unfavorable epidemiological trends in women and important evolution of the management of AAA call for an epidemiological surveillance of this disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of deoxynivalenol on calcium homeostasis of concanavalin A--Stimulated splenic lymphocytes of chickens in vitro.

PubMed

Ren, Zhihua; Wang, Yachao; Deng, Huidan; Deng, Youtian; Deng, Junliang; Zuo, Zhicai; Wang, Ya; Peng, Xi; Cui, Hengmin; Shen, Liuhong; Yu, Shumin; Cao, Suizhong

2016-04-01

In this study, the in vitro effects of the treatment of concanavalin A (Con A)--stimulated splenic lymphocytes with DON were examined. Splenic lymphocytes isolated from chickens were stimulated with 12.5 μg/mL Con A and exposed to deoxynivalenol (DON) (0-50 μg/mL) for 48 h. The intracellular calcium concentration ([Ca(2+)]i), pH, calmodulin (CaM) mRNA levels, and Na(+),K(+)-ATPase and Ca(2+)-ATPase activities were detected. With the DON exposure concentrations increased, the [Ca(2+)]i and CaM mRNA levels gradually increased in a dose-dependent manner, and all the evaluated conconcentrations affected ATPase activity to the same extent. There were significant differences (P<0.05 or P<0.01) between the treatment groups and the control group. These results indicate that an imbalance in calcium homeostasis and intracellular acidification are components of DON cytotoxicity in chicken lymphocytes. Copyright © 2016 Elsevier GmbH. All rights reserved.

Molecularly Defined Nanostructures Based on a Novel AAA-DDD Triple Hydrogen-Bonding Motif.

PubMed

Papmeyer, Marcus; Vuilleumier, Clément A; Pavan, Giovanni M; Zhurov, Konstantin O; Severin, Kay

2016-01-26

A facile and flexible method for the synthesis of a new AAA-DDD triple hydrogen-bonding motif is described. Polytopic supramolecular building blocks with precisely oriented AAA and DDD groups are thus accessible in few steps. These building blocks were used for the assembly of large macrocycles featuring four AAA-DDD interactions and a macrobicyclic complex with a total of six AAA-DDD interactions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Matrix metalloproteinase-2 gene variants and abdominal aortic aneurysm.

PubMed

Smallwood, L; Warrington, N; Allcock, R; van Bockxmeer, F; Palmer, L J; Iacopetta, B; Golledge, J; Norman, P E

2009-08-01

To investigate associations between two polymorphisms of the matrix metalloproteinase-2 gene (MMP2) and the incidence and progression of abdominal aortic aneurysm (AAA). Cases and controls were recruited from a trial of screening for AAAs. The association between two variants of MMP2 (-1360C>T, and +649C>T) in men with AAA (n=678) and in controls (n=659) was examined using multivariate analyses. The association with AAA expansion (n=638) was also assessed. In multivariate analyses with adjustments for multiple testing, no association between either SNP and AAA presence or expansion was detected. MMP2 -1360C>T and +649C>T variants are not risk factors for AAA.

The accuracy of combined physical examination and ultrasonography for the detection of abdominal aorta aneurysm.

PubMed

Cârstea, Doina; Streba, Letiţia Adela Maria; Glodeanu, Adina; Cârstea, A P; Vancu, Mihaela; Ninulescu, Ana-Maria

2008-01-01

Atherosclerosis is the most frequent cause in the appearance of an abdominal aorta aneurysm (AAA) and plays an important role in his development. Most AAA does not cause any symptoms, especially when talking about elderly patients, however, many of those aneurysms can be detected during physical examination. Their detection is very important because the natural evolution and the major reason in treating AAA is their tendency to rupture. We present the case of an adult man with a complex clinical pathology, but not related to the AAA. The diagnosis of the AAA has been suspicion through palpation, and the abdominal ultrasound exam confirmed it. This case is particular interesting, as the AAA requires surgical intervention, while patient's health status was poor. An essential issue is establishing the importance of the AAA screening, when there are no symptoms present. For now, there are not satisfactory studies to be used as a guide.

Inhibition of mTOR improves the impairment of acidification in autophagic vesicles caused by hepatic steatosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakadera, Eisuke; Yamashina, Shunhei, E-mail: syamashi@juntendo.ac.jp; Izumi, Kousuke

Recent investigations revealed that dysfunction of autophagy involved in the progression of chronic liver diseases such as alcoholic and nonalcoholic steatohepatitis and hepatocellular neoplasia. Previously, it was reported that hepatic steatosis disturbs autophagic proteolysis via suppression of both autophagic induction and lysosomal function. Here, we demonstrate that autophagic acidification was altered by a decrease in lysosomal proton pump vacuolar-ATPase (V-ATPase) in steatohepatitis. The number of autophagic vesicles was increased in hepatocytes from obese KKAy mice as compared to control. Similarly, autophagic membrane protein LC3-II and lysosomal protein LAMP-2 expression were enhanced in KKAy mice liver. Nevertheless, both phospho-mTOR and p62more » expression were augmented in KKAy mice liver. More than 70% of autophagosomes were stained by LysoTracker Red (LTR) in hepatocytes from control mice; however, the percentage of acidic autolysosomes was decreased in hepatocytes from KKAy mice significantly (40.1 ± 3.48%). Both protein and RNA level of V-ATPase subunits ATP6v1a, ATP6v1b, ATP6v1d in isolated lysosomes were suppressed in KKAy mice as compared to control. Interestingly, incubation with mTOR inhibitor rapamycin increased in the rate of LTR-positive autolysosomes in hepatocytes from KKAy mice and suppressed p62 accumulation in the liver from KKAy mice which correlated to an increase in the V-ATPase subunits expression. These results indicate that down-regulation of V-ATPase due to hepatic steatosis causes autophagic dysfunction via disruption of lysosomal and autophagic acidification. Moreover, activation of mTOR plays a pivotal role on dysregulation of lysosomal and autophagic acidification by modulation of V-ATPase expression and could therefore be a useful therapeutic target to ameliorate dysfunction of autophagy in NAFLD. - Highlights: • Hepatic steatosis causes accumulation of autophagic vesicles in hepatocytes. • Hepatic steatosis disturbs acidification of autophagic vesicles. • Lipid accumulation suppresses the expression of lysosomal V-ATPase subunits. • Rapamycin upregulates the expression of lysosomal V-ATPase suppressed in NAFLD. • Rapamycin ameliorates the acidification of autolysosomes impaired in NAFLD.« less

Quantitative HDL Proteomics Identifies Peroxiredoxin-6 as a Biomarker of Human Abdominal Aortic Aneurysm

PubMed Central

Burillo, Elena; Jorge, Inmaculada; Martínez-López, Diego; Camafeita, Emilio; Blanco-Colio, Luis Miguel; Trevisan-Herraz, Marco; Ezkurdia, Iakes; Egido, Jesús; Michel, Jean-Baptiste; Meilhac, Olivier; Vázquez, Jesús; Martin-Ventura, Jose Luis

2016-01-01

High-density lipoproteins (HDLs) are complex protein and lipid assemblies whose composition is known to change in diverse pathological situations. Analysis of the HDL proteome can thus provide insight into the main mechanisms underlying abdominal aortic aneurysm (AAA) and potentially detect novel systemic biomarkers. We performed a multiplexed quantitative proteomics analysis of HDLs isolated from plasma of AAA patients (N = 14) and control study participants (N = 7). Validation was performed by western-blot (HDL), immunohistochemistry (tissue), and ELISA (plasma). HDL from AAA patients showed elevated expression of peroxiredoxin-6 (PRDX6), HLA class I histocompatibility antigen (HLA-I), retinol-binding protein 4, and paraoxonase/arylesterase 1 (PON1), whereas α-2 macroglobulin and C4b-binding protein were decreased. The main pathways associated with HDL alterations in AAA were oxidative stress and immune-inflammatory responses. In AAA tissue, PRDX6 colocalized with neutrophils, vascular smooth muscle cells, and lipid oxidation. Moreover, plasma PRDX6 was higher in AAA (N = 47) than in controls (N = 27), reflecting increased systemic oxidative stress. Finally, a positive correlation was recorded between PRDX6 and AAA diameter. The analysis of the HDL proteome demonstrates that redox imbalance is a major mechanism in AAA, identifying the antioxidant PRDX6 as a novel systemic biomarker of AAA. PMID:27934969

High aryl acylamidase activity associated with cobra venom acetylcholinesterase: biological significance.

PubMed

Rajesh, Ramanna V; Layer, Paul G; Boopathy, Rathanam

2009-01-01

Investigation of the non-classical functions of cholinesterases (ChEs) has been the subject of interest in the past three decades. One of which is aryl acylamidase (AAA) activity associated with ChEs, but characterized in in vitro, as an enzyme, splitting the artificial substrate o-nitroacetanilide with unknown physiological function. In the present study, we have compared levels of AAA activity of AChE from different sources like goat brain, electric eel organ and from venoms of different snakes. Remarkably cobra venom showed the highest AAA activity and also high AAA/AChE ratio. Both serotonergenic and cholinergic inhibitors inhibited the cobra venom AAA activity in a concentration dependent manner, which also underlines the association of AAA with AChE of cobra venom. The study becomes interesting because of i) the cobra venom AChE exists in monomeric globular forms; ii) in Alzheimer's disease too the most abundant forms of cholinesterases are monomeric globular forms, thought to be involved in the pathogenesis of Alzheimer's disease; iii) the effect of Alzheimer's disease drugs on the AAA activity of cobra venom, indicated that AAA activity of cobra venom was more sensitive than AChE and iv) Huperzine and Tacrine showed more pronounced effect on AAA. Thus, this study elucidates the high AAA associated with cobra venom AChE may serve as one of the prominent activity to test the pharmacological effect of AD drugs, as other sources were found to have lower activity.

TGFβ (Transforming Growth Factor-β) Blockade Induces a Human-Like Disease in a Nondissecting Mouse Model of Abdominal Aortic Aneurysm.

PubMed

Lareyre, Fabien; Clément, Marc; Raffort, Juliette; Pohlod, Stefanie; Patel, Meghana; Esposito, Bruno; Master, Leanne; Finigan, Alison; Vandestienne, Marie; Stergiopulos, Nikolaos; Taleb, Soraya; Trachet, Bram; Mallat, Ziad

2017-11-01

Current experimental models of abdominal aortic aneurysm (AAA) do not accurately reproduce the major features of human AAA. We hypothesized that blockade of TGFβ (transforming growth factor-β) activity-a guardian of vascular integrity and immune homeostasis-would impair vascular healing in models of nondissecting AAA and would lead to sustained aneurysmal growth until rupture. Here, we test this hypothesis in the elastase-induced AAA model in mice. We analyze AAA development and progression using ultrasound in vivo, synchrotron-based ultrahigh resolution imaging ex vivo, and a combination of biological, histological, and flow cytometry-based cellular and molecular approaches in vitro. Systemic blockade of TGFβ using a monoclonal antibody induces a transition from a self-contained aortic dilatation to a model of sustained aneurysmal growth, associated with the formation of an intraluminal thrombus. AAA growth is associated with wall disruption but no medial dissection and culminates in fatal transmural aortic wall rupture. TGFβ blockade enhances leukocyte infiltration both in the aortic wall and the intraluminal thrombus and aggravates extracellular matrix degradation. Early blockade of IL-1β or monocyte-dependent responses substantially limits AAA severity. However, blockade of IL-1β after disease initiation has no effect on AAA progression to rupture. Endogenous TGFβ activity is required for the healing of AAA. TGFβ blockade may be harnessed to generate new models of AAA with better relevance to the human disease. We expect that the new models will improve our understanding of the pathophysiology of AAA and will be useful in the identification of new therapeutic targets. © 2017 American Heart Association, Inc.

Genetic analysis on HLA loci in Japanese patients with abdominal aortic aneurysm.

PubMed

Sugimoto, T; Sada, M; Miyamoto, T; Yao, H

2003-08-01

autoimmunity has been proposed as one of the pathogenesis of abdominal aortic aneurysm (AAA). There is also a likelihood that when aorto-iliac occlusive disease (AIOD) coexists with AAA, some other occlusive atherosclerotic diseases, such as ischemic heart disease and cerebrovascular disease, may develop, leading to a very poor long-term prognosis. Previous studies using serological HLA typing showed that HLA-DR15 was a risk factor for AAA. In this study, we performed HLA-DNA typing by PCR to clarify the relationship between AAA and HLA genotypes in Japanese patients with AAA. In addition, we analyzed whether HLA genotypes are involved in the pathogenesis of AIOD. we examined 78 HLA genotypes of class I (HLA-A and -B) and class II (HLA-DR) and found that 60.4 and 30.4% of 49 AAA patients had HLA-A2 and HLA-B61, respectively. These frequencies were significantly higher than those in control individuals (HLA-A2, p < 0.05; HLA-B61, p < 0.005). We also found that 55.6% of nine AAA patients with AIOD had both HLA-B52 and HLA-DR B1*1502. In contrast, only 10.0% each of 40 AAA patients without AIOD showed HLA-B53 or HLA-DR B1*1502. this study showed that HLA A-2 and HLA B-61, but not HLA DR-15, were important genetic risk factors for the development of AAA among the Japanese population. We also found high frequencies of HLA-B52 and HLA-DR B1*1502 in the AAA patients with AIOD than in those without, although this must be confirmed using a larger number of AAA patients with AIOD.

Inhibition of plasmin-mediated TAFI activation may affect development but not progression of abdominal aortic aneurysms

PubMed Central

Bridge, Katherine; Revill, Charlotte; Macrae, Fraser; Bailey, Marc; Yuldasheva, Nadira; Wheatcroft, Stephen; Butlin, Roger; Foster, Richard; Scott, D. Julian; Gils, Ann; Ariёns, Robert

2017-01-01

Objective Thrombin-activatable fibrinolysis inhibitor (TAFI) reduces the breakdown of fibrin clots through its action as an indirect inhibitor of plasmin. Studies in TAFI-deficient mice have implicated a potential role for TAFI in Abdominal Aortic Aneurysm (AAA) disease. The role of TAFI inhibition on AAA formation in adult ApoE-/- mice is unknown. The aim of this paper was to investigate the effects of TAFI inhibition on AAA development and progression. Methods Using the Angiotensin II model of AAA, male ApoE-/- mice were infused with Angiotensin II 750ng/kg/min with or without a monoclonal antibody inhibitor of plasmin-mediated activation of TAFI, MA-TCK26D6, or a competitive small molecule inhibitor of TAFI, UK-396082. Results Inhibition of TAFI in the Angiotensin II model resulted in a decrease in the mortality associated with AAA rupture (from 40.0% to 16.6% with MA-TCK26D6 (log-rank Mantel Cox test p = 0.16), and 8.3% with UK-396082 (log-rank Mantel Cox test p = 0.05)). Inhibition of plasmin-mediated TAFI activation reduced the incidence of AAA from 52.4% to 30.0%. However, late treatment with MA-TCK26D6 once AAA were already established had no effect on the progression of AAA in this model. Conclusions The formation of intra-mural thrombus is responsible for the dissection and early rupture in the angiotensin II model of AAA, and this process can be prevented through inhibition of TAFI. Late treatment with a TAFI inhibitor does not prevent AAA progression. These data may indicate a role for inhibition of plasmin-mediated TAFI activation in the early stages of AAA development, but not in its progression. PMID:28472123

Endothelium as a Potential Target for Treatment of Abdominal Aortic Aneurysm

PubMed Central

Sun, Jingyuan; Deng, Hongping; Zhou, Zhen

2018-01-01

Abdominal aortic aneurysm (AAA) was previously ascribed to weaken defective medial arterial/adventitial layers, for example, smooth muscle/fibroblast cells. Therefore, besides surgical repair, medications targeting the medial layer to strengthen the aortic wall are the most feasible treatment strategy for AAA. However, so far, it is unclear whether such drugs have any beneficial effect on AAA prognosis, rate of aneurysm growth, rupture, or survival. Notably, clinical studies have shown that AAA is highly associated with endothelial dysfunction in the aged population. Additionally, animal models of endothelial dysfunction and endothelial nitric oxide synthase (eNOS) uncoupling had a very high rate of AAA formation, indicating there is crucial involvement of the endothelium and a possible pharmacological solution targeting the endothelium in AAA treatment. Endothelial cells have been found to trigger vascular wall remodeling by releasing proteases, or recruiting macrophages along with other neutrophils, into the medial layer. Moreover, inflammation and oxidative stress of the arterial wall were induced by endothelial dysfunction. Interestingly, there is a paradoxical differential correlation between diabetes and aneurysm formation in retinal capillaries and the aorta. Deciphering the significance of such a difference may explain current unsuccessful AAA medications and offer a solution to this treatment challenge. It is now believed that AAA and atherosclerosis are two separate but related diseases, based on their different clinical patterns which have further complicated the puzzle. Therefore, a thorough investigation of the interaction between endothelium and medial/adventitial layer may provide us a better understanding and new perspective on AAA formation, especially after taking into account the importance of endothelium in the development of AAA. Moreover, a novel medication strategy replacing the currently used, but suboptimal treatments for AAA, could be informed with this analysis. PMID:29849906

Combination of endovascular graft exclusion and drug therapy in AAA with hypertension or hyperglycemia.

PubMed

Wang, Dile; Qu, Bihui; He, Tao

2017-08-01

The objective of the present study was to evaluate the efficacy of combination of endovascular graft exclusion and drugs for hypertension/hyperglycemia for the treatment of abdominal aortic aneurysm (AAA). We analyzed 156 patients with AAA. Eighty-four patients were hypertensive and 72 were hyperglycemic. After endovascular graft exclusion, hypertensive patients were divided into four groups and treated with cyclopenthiazide, reserpine, propranolol, and placebo respectively. Hyperglycemic patients were divided into three groups and treated with metformin, insulin, and placebo respectively. Body temperature and peripheral blood leukocytes were measured at day 1, 2, 7, and 14 after endovascular graft exclusion. Size of AAAs, blood pressure, and blood sugar were measured again after 1 year. In hypertensive patients, the size of AAAs reduced after endovascular graft exclusion, while the combined treatments with cyclopenthiazide, reserpine, or propranolol helped to reduce blood pressure (blood pressure decrease <10 mmHg (18/21), <10 mmHg (12/21), <10 mmHg (8/21), and <10 mmHg (10/21) in the control group, cyclopenthiazide group, reserpine group, and propranolol group, respectively. AAA size decreased in the control group (P<0.001) and in the other three groups (P<0.0001). Similar results were obtained in hyperglycemic patients. The size of AAAs reduced after endovascular graft exclusion. Combined treatment with Metformin and Insulin reduced blood sugar (control, blood sugar >7.8 mmol/L (22/24), AAA size (P<0.001); metformin, blood sugar >7.8 mmol/L (14/24), AAA size (P<0.0001); insulin, blood sugar >7.8 mmol/L (11/24), AAA size (P<0.0001). Combination of endovascular graft exclusion with medicine is more effective than the former treatment alone for AAA therapy.

NASA Airborne Astronomy Ambassadors (AAA) Professional Development and NASA Connections

NASA Astrophysics Data System (ADS)

Backman, D. E.; Clark, C.; Harman, P. K.

2017-12-01

NASA's Airborne Astronomy Ambassadors (AAA) program is a three-part professional development (PD) experience for high school physics, astronomy, and earth science teachers. AAA PD consists of: (1) blended learning via webinars, asynchronous content learning, and in-person workshops, (2) a STEM immersion experience at NASA Armstrong's B703 science research aircraft facility in Palmdale, California, and (3) ongoing opportunities for connection with NASA astrophysics and planetary science Subject Matter Experts (SMEs). AAA implementation in 2016-18 involves partnerships between the SETI Institute and seven school districts in northern and southern California. AAAs in the current cohort were selected by the school districts based on criteria developed by AAA program staff working with WestEd evaluation consultants. The selected teachers were then randomly assigned by WestEd to a Group A or B to support controlled testing of student learning. Group A completed their PD during January - August 2017, then participated in NASA SOFIA science flights during fall 2017. Group B will act as a control during the 2017-18 school year, then will complete their professional development and SOFIA flights during 2018. A two-week AAA electromagnetic spectrum and multi-wavelength astronomy curriculum aligned with the Science Framework for California Public Schools and Next Generation Science Standards was developed by program staff for classroom delivery. The curriculum (as well as the AAA's pre-flight PD) capitalizes on NASA content by using "science snapshot" case studies regarding astronomy research conducted by SOFIA. AAAs also interact with NASA SMEs during flight weeks and will translate that interaction into classroom content. The AAA program will make controlled measurements of student gains in standards-based learning plus changes in student attitudes towards STEM, and observe & record the AAAs' implementation of curricular changes. Funded by NASA: NNX16AC51

Characterization of the Modular Design of the Autolysin/Adhesin Aaa from Staphylococcus Aureus

PubMed Central

Hirschhausen, Nina; Schlesier, Tim; Peters, Georg; Heilmann, Christine

2012-01-01

Background Staphylococcus aureus is a frequent cause of serious and life-threatening infections, such as endocarditis, osteomyelitis, pneumonia, and sepsis. Its adherence to various host structures is crucial for the establishment of diseases. Adherence may be mediated by a variety of adhesins, among them the autolysin/adhesins Atl and Aaa. Aaa is composed of three N-terminal repeated sequences homologous to a lysin motif (LysM) that can confer cell wall attachment and a C-terminally located cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domain having bacteriolytic activity in many proteins. Methodology/Principal Findings Here, we show by surface plasmon resonance that the LysM domain binds to fibrinogen, fibronectin, and vitronectin respresenting a novel adhesive function for this domain. Moreover, we demonstrated that the CHAP domain not only mediates the bacteriolytic activity, but also adherence to fibrinogen, fibronectin, and vitronectin, thus demonstrating for the first time an adhesive function for this domain. Adherence of an S. aureus aaa mutant and the complemented aaa mutant is slightly decreased and increased, respectively, to vitronectin, but not to fibrinogen and fibronectin, which might at least in part result from an increased expression of atl in the aaa mutant. Furthermore, an S. aureus atl mutant that showed enhanced adherence to fibrinogen, fibronectin, and endothelial cells also demonstrated increased aaa expression and production of Aaa. Thus, the redundant functions of Aaa and Atl might at least in part be interchangeable. Lastly, RT-PCR and zymographic analysis revealed that aaa is negatively regulated by the global virulence gene regulators agr and SarA. Conclusions/Significance We identified novel functions for two widely distributed protein domains, LysM and CHAP, i.e. the adherence to the extracellular matrix proteins fibrinogen, fibronectin, and vitronectin. The adhesive properties of Aaa might promote S. aureus colonization of host extracellular matrix and tissue, suggesting a role for Aaa in the pathogenesis of S. aureus infections. PMID:22768285

Characterization of the modular design of the autolysin/adhesin Aaa from Staphylococcus aureus.

PubMed

Hirschhausen, Nina; Schlesier, Tim; Peters, Georg; Heilmann, Christine

2012-01-01

Staphylococcus aureus is a frequent cause of serious and life-threatening infections, such as endocarditis, osteomyelitis, pneumonia, and sepsis. Its adherence to various host structures is crucial for the establishment of diseases. Adherence may be mediated by a variety of adhesins, among them the autolysin/adhesins Atl and Aaa. Aaa is composed of three N-terminal repeated sequences homologous to a lysin motif (LysM) that can confer cell wall attachment and a C-terminally located cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domain having bacteriolytic activity in many proteins. Here, we show by surface plasmon resonance that the LysM domain binds to fibrinogen, fibronectin, and vitronectin respresenting a novel adhesive function for this domain. Moreover, we demonstrated that the CHAP domain not only mediates the bacteriolytic activity, but also adherence to fibrinogen, fibronectin, and vitronectin, thus demonstrating for the first time an adhesive function for this domain. Adherence of an S. aureus aaa mutant and the complemented aaa mutant is slightly decreased and increased, respectively, to vitronectin, but not to fibrinogen and fibronectin, which might at least in part result from an increased expression of atl in the aaa mutant. Furthermore, an S. aureus atl mutant that showed enhanced adherence to fibrinogen, fibronectin, and endothelial cells also demonstrated increased aaa expression and production of Aaa. Thus, the redundant functions of Aaa and Atl might at least in part be interchangeable. Lastly, RT-PCR and zymographic analysis revealed that aaa is negatively regulated by the global virulence gene regulators agr and SarA. We identified novel functions for two widely distributed protein domains, LysM and CHAP, i.e. the adherence to the extracellular matrix proteins fibrinogen, fibronectin, and vitronectin. The adhesive properties of Aaa might promote S. aureus colonization of host extracellular matrix and tissue, suggesting a role for Aaa in the pathogenesis of S. aureus infections.

The interleukin-10-1082 'A' allele and abdominal aortic aneurysms.

PubMed

Bown, Matthew J; Lloyd, Geraint M; Sandford, Rebecca M; Thompson, John R; London, Nicholas J M; Samani, Nilesh J; Sayers, Robert D

2007-10-01

Abdominal aortic aneurysms (AAA) are caused by inflammatory processes in the wall of the aorta resulting in degradation of structural proteins. This inflammatory process is mediated, in part, by cytokines, and interleukin-10 (IL-10) is a predominantly anti-inflammatory cytokine. A single nucleotide polymorphism in the promoter region of the IL-10 gene that affects transcription has been associated with AAA in a small study. The aim of this study was to determine whether this polymorphism is associated with AAA and also examine its effect on the growth of small AAA. A case control study was performed. A total of 389 patients with AAA and 404 healthy controls were recruited. IL-10-1082 polymorphisms were determined by polymerase chain reaction-based methods. In the case of patients with small AAA (<5.5 cm), serial size measurements were recorded to determine mean growth rate. There was a statistically significant difference both in allele and genotype frequencies between the case and control groups with the IL-10-1082 'A' allele being more common in the AAA group (P = .006). In the AAA group, genotype frequencies were as follows: GG 84, GA 201, and AA 104. In the control group, the genotype frequencies were GG 118, GA 205, and AA 81. The odds ratio for the 'A' allele as a risk factor for AAA was 1.50 (95% confidence interval 1.09 to 2.07). Regression modeling revealed that the IL-10-1082 genotype was, however, not independently associated with AAA if age, tobacco use, hypertension, and history of coronary or peripheral artery disease was taken into account. There was a trend towards lower plasma IL-10 level in IL-10 AA carriers, but the IL-10 'A' allele did not have any discernible effect on the growth of small AAA. This study demonstrates that the IL-10-1082 'A' allele is associated with AAA, although this association is likely to be secondary to an association between IL-10-1082 genotype and other markers of cardiovascular disease rather than AAA per se.

Loss of MURC/Cavin-4 induces JNK and MMP-9 activity enhancement in vascular smooth muscle cells and exacerbates abdominal aortic aneurysm.

PubMed

Miyagawa, Kotaro; Ogata, Takehiro; Ueyama, Tomomi; Kasahara, Takeru; Nakanishi, Naohiko; Naito, Daisuke; Taniguchi, Takuya; Hamaoka, Tetsuro; Maruyama, Naoki; Nishi, Masahiro; Kimura, Taizo; Yamada, Hiroyuki; Aoki, Hiroki; Matoba, Satoaki

2017-06-03

Abdominal aortic aneurysm (AAA) is relatively common in elderly patients with atherosclerosis. MURC (muscle-restricted coiled-coil protein)/Cavin-4 modulating the caveolae function of muscle cells is expressed in cardiomyocytes, skeletal muscle cells and smooth muscle cells. Here, we show a novel functional role of MURC/Cavin-4 in vascular smooth muscle cells (VSMCs) and AAA development. Both wild-type (WT) and MURC/Cavin-4 knockout (MURC -/- ) mice subjected to periaortic application of CaCl 2 developed AAAs. Six weeks after CaCl 2 treatment, internal and external aortic diameters were significantly increased in MURC -/- AAAs compared with WT AAAs, which were accompanied by advanced fibrosis in the tunica media of MURC -/- AAAs. The activity of JNK and matrix metalloproteinase (MMP) -2 and -9 were increased in MURC -/- AAAs compared with WT AAAs at 5 days after CaCl 2 treatment. At 6 weeks after CaCl 2 treatment, MURC -/- AAAs exhibited attenuated JNK activity compared with WT AAAs. There was no difference in the activity of MMP-2 or -9 between saline and CaCl 2 treatments. In MURC/Cavin-4-knockdown VSMCs, TNFα-induced activity of JNK and MMP-9 was enhanced compared with control VSMCs. Furthermore, WT, MURC -/- , apolipoprotein E -/- (ApoE -/- ), and MURC/Cavin-4 and ApoE double-knockout (MURC -/- ApoE -/- ) mice were subjected to angiotensin II (Ang II) infusion. In both ApoE -/- and MURC -/- ApoE -/- mice infused for 4 weeks with Ang II, AAAs were promoted. The internal aortic diameter was significantly increased in Ang II-infused MURC -/- ApoE -/- mice compared with Ang II-infused ApoE -/- mice. In MURC/Cavin-4-knockdown VSMCs, Ang II-induced activity of JNK and MMP-9 was enhanced compared with control VSMCs. Our results suggest that MURC/Cavin-4 in VSMCs modulates AAA progression at the early stage via the activation of JNK and MMP-9. MURC/Cavin-4 is a potential therapeutic target against AAA progression. Copyright © 2017 Elsevier Inc. All rights reserved.

Abdominal aortic aneurysm screening program in Poland.

PubMed

Jawien, A; Formankiewicz, B; Derezinski, T; Migdalski, A; Brazis, P; Woda, L

Screening for abdominal aortic aneurysms (AAA) is currently recommended by several vascular societies. In countries where it has been introduced the prevalence of AAAs differed greatly and was mainly related to cigarette smoking. The screening program also had an enormous impact on the decrease of AAA ruptures and reduced mortality rate. These facts have led to the introduction of the first screening program for AAAs in Poland. The aim of the study was to determine the prevalence of AAAs among men aged 60 years and older undergoing ultrasound examination of the abdominal aorta. A single ultrasonography of the abdomen was performed to assess the aorta from the renal arteries to the bifurcation and the diameter of the aorta was measured at its widest point. The cut-off value for determining an aortic aneurysm was set at a diameter of ≥ 30 mm. All ultrasonography measurements were performed by physicians in outpatient departments throughout the Kuyavian-Pomeranian Province. Additionally, each subject had to fill out a questionnaire with demographic data, smoking habits, existing comorbidities and familial occurrence of AAAs. The study was conducted from October 2009 to November 2011. The abdominal aorta ultrasound examinations were carried out in 1556 men aged 60 years and older. The prevalence of AAA in the study population was 6.0 % (94 out of 1556). The average age of the men was 69 years (SD 6 years, range 60-92 years). In the study population 55 % of the men smoked or had smoked and 3 % were aware of the presence of AAAs in family members. There were three risk factors significantly associated with the presence of AAAs: age (p < 0.05), smoking (72.3 % vs 53.9 %, p = 0.004) and family history of AAAs (9.6 % vs 2.7 %, p = 0.017). The prevalence of AAAs among men in Poland is higher than in other European countries and the USA. The screening program for AAAs is an easy and reliable method for detecting early stages of the disease and risk factors which are the driving forces for the development of AAAs.

Vitamins and abdominal aortic aneurysm.

PubMed

Takagi, Hisato; Umemoto, Takuya

2017-02-01

To summarize the association of vitamins (B6, B12, C, D, and E) and abdominal aortic aneurysm (AAA), we reviewed clinical studies with a comprehensive literature research and meta-analytic estimates. To identify all clinical studies evaluating the association of vitamins B6/B12/C/D/E and AAA, databases including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched through April 2015, using Web-based search engines (PubMed and OVID). For each case-control study, data regarding vitamin levels in both the AAA and control groups were used to generate standardized mean differences (SMDs) and 95% confidence intervals (CIs). Pooled analyses of the 4 case-control studies demonstrated significantly lower circulating vitamin B6 levels (SMD, -0.33; 95% CI, -0.55 to -0.11; P=0.003) but non-significantly lower vitamin B12 levels (SMD, -0.42; 95% CI, -1.09 to 0.25; P=0.22) in patients with AAA than subjects without AAA. Pooled analyses of the 2 case-control studies demonstrated significantly lower levels of circulating vitamins C (SMD, -0.71; 95% CI, -1.23 to -0.19; P=0.007) and E (SMD, -1.76; 95% CI, -2.93 to 0.60; P=0.003) in patients with AAA than subjects without AAA. Another pooled analysis of the 3 case-control studies demonstrated significantly lower circulating vitamin D (25-hydroxyvitamin D) levels (SMD, -0.25; 95% CI, -0.50 to -0.01; P=0.04) in patients with AAA than subjects without AAA. In a double-blind controlled trial, 4.0-year treatment with a high-dose folic acid and vitamin B6/B12 multivitamin in kidney transplant recipients did not reduce a rate of AAA repair despite significant reduction in homocysteine level. In another randomized, double-blind, placebo-controlled trial, 5.8-year supplementation with α-tocopherol (vitamin E) had no preventive effect on large AAA among male smokers. In clinical setting, although low circulating vitamins B6/C/D/E (not B12) levels are associated with AAA presence, vitamins B6/B12/E supplementation may not reduce AAA incidence.

Feasibility of wall stress analysis of abdominal aortic aneurysms using three-dimensional ultrasound.

PubMed

Kok, Annette M; Nguyen, V Lai; Speelman, Lambert; Brands, Peter J; Schurink, Geert-Willem H; van de Vosse, Frans N; Lopata, Richard G P

2015-05-01

Abdominal aortic aneurysms (AAAs) are local dilations that can lead to a fatal hemorrhage when ruptured. Wall stress analysis of AAAs is a novel tool that has proven high potential to improve risk stratification. Currently, wall stress analysis of AAAs is based on computed tomography (CT) and magnetic resonance imaging; however, three-dimensional (3D) ultrasound (US) has great advantages over CT and magnetic resonance imaging in terms of costs, speed, and lack of radiation. In this study, the feasibility of 3D US as input for wall stress analysis is investigated. Second, 3D US-based wall stress analysis was compared with CT-based results. The 3D US and CT data were acquired in 12 patients (diameter, 35-90 mm). US data were segmented manually and compared with automatically acquired CT geometries by calculating the similarity index and Hausdorff distance. Wall stresses were simulated at P = 140 mm Hg and compared between both modalities. The similarity index of US vs CT was 0.75 to 0.91 (n = 12), with a median Hausdorff distance ranging from 4.8 to 13.9 mm, with the higher values found at the proximal and distal sides of the AAA. Wall stresses were in accordance with literature, and a good agreement was found between US- and CT-based median stresses and interquartile stresses, which was confirmed by Bland-Altman and regression analysis (n = 8). Wall stresses based on US were typically higher (+23%), caused by geometric irregularities due to the registration of several 3D volumes and manual segmentation. In future work, an automated US registration and segmentation approach is the essential point of improvement before pursuing large-scale patient studies. This study is a first step toward US-based wall stress analysis, which would be the modality of choice to monitor wall stress development over time because no ionizing radiation and contrast material are involved. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Cost-effectiveness of targeted screening for abdominal aortic aneurysm. Monte Carlo-based estimates.

PubMed

Pentikäinen, T J; Sipilä, T; Rissanen, P; Soisalon-Soininen, S; Salo, J

2000-01-01

This article reports a cost-effectiveness analysis of targeted screening for abdominal aortic aneurysm (AAA). A major emphasis was on the estimation of distributions of costs and effectiveness. We performed a Monte Carlo simulation using C programming language in a PC environment. Data on survival and costs, and a majority of screening probabilities, were from our own empirical studies. Natural history data were based on the literature. Each screened male gained 0.07 life-years at an incremental cost of FIM 3,300. The expected values differed from zero very significantly. For females, expected gains were 0.02 life-years at an incremental cost of FIM 1,100, which was not statistically significant. Cost-effectiveness ratios and their 95% confidence intervals were FIM 48,000 (27,000-121,000) and 54,000 (22,000-infinity) for males and females, respectively. Sensitivity analysis revealed that the results for males were stable. Individual variation in life-year gains was high. Males seemed to benefit from targeted AAA screening, and the results were stable. As far as the cost-effectiveness ratio is considered acceptable, screening for males seemed to be justified. However, our assumptions about growth and rupture behavior of AAAs might be improved with further clinical and epidemiological studies. As a point estimate, females benefited in a similar manner, but the results were not statistically significant. The evidence of this study did not justify screening of females.

Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigala, Barbara; Edwards, Mina; Puri, Teena

2005-11-01

TIP48 is a highly conserved eukaryotic AAA{sup +} protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis,more » TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis.« less

High risk endovascular aneurysm repair: a case report.

PubMed

De Silva, Samanthi

2017-10-01

Mr AB is a 66-year old gentleman who presented for elective endovascular aneurysm repair (EVAR) following a routine screening scan identifying a 5.5cm abdominal aortic aneurysm (AAA). He had a past history of chronic obstructive pulmonary disease (COPD) with FEV1/FVC ratio of 48% on pre-assessment. He was hypertensive with a history of ischaemic heart disease (IHD), which has remained asymptomatic following coronary artery bypass grafting (CABG) eight years prior to this presentation. Copyright the Association for Perioperative Practice.

The Antiaircraft Journal. Volume 94, Number 6, November-December 1951

DTIC Science & Technology

1951-12-01

authorized by the Visiting Forces Act. Getting their heads together, the Yanks and Tommies have discovered each other to be pretty regular fellows...Francis A., to 3Sth AAA Brig, Ft Meade, Md. McDaniel, Otto L., to Hq Fourth Army, Ft Sam Houston, Tex. Pape, Robin B., to SOth AAA Gp, Ft Totten , NY...to 71 Sth AAA Gun Bn, Ft Totten , NJ. Kee, Pat M., to 209th AAA Gp, Indiantown Gap, Pa. Kennaman, Jack R., to SOlst AAA Gun Bn, North Richland, Wash

Using Genetic Buffering Relationships Identified in Fission Yeast To Elucidate the Molecular Pathology of Tuberous Sclerosis

DTIC Science & Technology

2016-07-01

5’-aat tat ttt ata tgg aat gag caa gta tgt ttt atc ata att gac cag ttc att tca agg acc ttc aaa aat ata cct acg aat tcg agc tcg ttt aaa c-3’), or...oTsc13 (5’-tta aga gtt cag att tgc ttt atg tgg tta ttc tgc tga agg tcc taa ttt att gac gtt gaa aaa taa agg cca cat agc gga tcc ccg ggt taa tta a-3...and oTsc14 (5’-ata aaa aaa att aat taa tga tgg caa ggc aca atc gta atc aat ctt tta att tag gac ttt tta tat gcc ctt atg gcg aat tcg agc tcg ttt aaa c

Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells

PubMed Central

Zhen, Hong; Huang, Ming; Zheng, Xi; Feng, Lixing; Jiang, Baohong; Yang, Min; Wu, Wanying; Liu, Xuan; Guo, Dean

2016-01-01

Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the expression of Na, K-ATPase α1 and α3 subunits and increased the expression of WEE1 in HeLa cells. Antibodies against Na, K-ATPase α1 and α3 subunits alone or combinated with arenobufagin also inhibited the activity of proteasome. Furthermore, the expression of the possible intermediate proteins ataxin-1 and translationally-controlled tumor protein was increased in HeLa cells treated with arenobufagin by flow cytometry analysis, respectively. These results indicated that arenobufagin might directly bind with Na, K-ATPase α1 and α3 subunits and the inhibitive effect of arenobufagin on proteasomal activity of HeLa cells might be related to its binding with Na, K-ATPase. PMID:27428326

Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells.

PubMed

Yue, Qingxi; Zhen, Hong; Huang, Ming; Zheng, Xi; Feng, Lixing; Jiang, Baohong; Yang, Min; Wu, Wanying; Liu, Xuan; Guo, Dean

2016-01-01

Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the expression of Na, K-ATPase α1 and α3 subunits and increased the expression of WEE1 in HeLa cells. Antibodies against Na, K-ATPase α1 and α3 subunits alone or combinated with arenobufagin also inhibited the activity of proteasome. Furthermore, the expression of the possible intermediate proteins ataxin-1 and translationally-controlled tumor protein was increased in HeLa cells treated with arenobufagin by flow cytometry analysis, respectively. These results indicated that arenobufagin might directly bind with Na, K-ATPase α1 and α3 subunits and the inhibitive effect of arenobufagin on proteasomal activity of HeLa cells might be related to its binding with Na, K-ATPase.

48 CFR 316.505 - Ordering.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CONTRACT TYPES TYPES OF CONTRACTS Indefinite-Delivery Contracts 316.505 Ordering. (b)(5) The HHS task-order and delivery-order ombudsman is the Director, Strategic Acquisition Service, PSC. The task-order and... of Performance Accountability, Resources and Technology ASPR/OAMCG: Chief of Acquisition Policy CDC...

Notch γ-Secretase Inhibitor Dibenzazepine Attenuates Angiotensin II-Induced Abdominal Aortic Aneurysm in ApoE Knockout Mice by Multiple Mechanisms

PubMed Central

Zheng, Yue-Hong; Li, Fang-Da; Tian, Cui; Ren, Hua-Liang; Du, Jie; Li, Hui-Hua

2013-01-01

Abdominal aortic aneurysm (AAA) is a life-threatening aortic disease in the elderly. Activation of Notch1 pathway plays a critical role in the development of AAA, but the underlying mechanisms remain poorly understood. In the present study, we explored the mechanisms by which Notch1 activation regulates angiotensin II (Ang II)-induced AAA formation and evaluated the therapeutic potential of a new Notch γ-secretase inhibitor, dibenzazepine (DBZ), for the treatment of AAA. Apolipoprotein E knockout (Apo E−/−) mice infused for 4 weeks with Ang II (1000 ng/kg/min, IP) using osmotic mini-pumps were received an intraperitoneal injection of either vehicle or 1 mg/kg/d DBZ. Notch1 signaling was activated in AAA tissue from both Ang II-infused Apo E−/− mice and human undergoing AAA repair in vivo, with increased expression of Notch intracellular domain (NICD) and its target gene Hes1, and this effect was effectively blocked by DBZ. Moreover, infusion of Ang II markedly increased the incidence and severity of AAA in Apo E−/− mice. In contrast, inhibition of Notch activation by DBZ prevented AAA formation in vivo. Furthermore, DBZ markedly prevented Ang II-stimulated accumulation of macrophages and CD4+ T cells, and ERK-mediated angiogenesis, simultaneously reversed Th2 response, in vivo. In conclusion, these findings provide new insight into the multiple mechanisms of Notch signaling involved in AAA formation and suggest that γ-secretase inhibitor DBZ might be a novel therapeutic drug for treating AAAS. PMID:24358274

Abdominal aortic aneurysm repair in New Zealand: a validation of the Australasian Vascular Audit.

PubMed

Khashram, Manar; Thomson, Ian A; Jones, Gregory T; Roake, Justin A

2017-05-01

In New Zealand (NZ), there are two major sources of operative data for abdominal aortic aneurysm (AAA) repair: the Australasian Vascular Audit (AVA) and the National Minimum Data Set (NMDS). Since the introduction of the AVA in NZ, there has not been any attempt at the validation of outcome data. The aims of this study were to report the outcomes of AAA repair and validate the AAA data captured by AVA using the NMDS. AAA procedures performed in NZ from January 2010 to December 2014 were extracted from the AVA and NMDS. Patients identified from the AVA had their survival status matched to the NMDS. Only primary AAA procedures were included for the analysis, with re-interventions and graft infections excluded. Demographical, risk factors and outcome data were used for validation. The number of patients undergoing primary AAA procedure from AVA and NMDS was 1713 and 2078, respectively. The AVA inpatient mortality for elective and rupture AAA was 1.6 and 32.2%, respectively. The NMDS 30-day mortality from AAA was 2.5 and 31.5%. Overall, 1604 patients were available for matching, and the NMDS correctly reported 98.1% of endovascular aneurysm repair and 94.2% of elective AAA repairs; however, there were major differences in comorbidity reporting between the data sets. Both data sets were incomplete, but combining administrative (NMDS) and clinical (AVA) data sets provided a more accurate assessment of mortality figures. More than 80% of AAA repairs are captured by AVA, but further work to improve compliance and comorbidity documentation is required. © 2016 Royal Australasian College of Surgeons.

Branched chain and aromatic amino acids change acutely following two medical therapies for type 2 diabetes mellitus.

PubMed

Walford, Geoffrey A; Davis, Jaclyn; Warner, A Sofia; Ackerman, Rachel J; Billings, Liana K; Chamarthi, Bindu; Fanelli, Rebecca R; Hernandez, Alicia M; Huang, Chunmei; Khan, Sabina Q; Littleton, Katherine R; Lo, Janet; McCarthy, Rita M; Rhee, Eugene P; Deik, Amy; Stolerman, Elliot; Taylor, Andrew; Hudson, Margo S; Wang, Thomas J; Altshuler, David; Grant, Richard W; Clish, Clary B; Gerszten, Robert E; Florez, Jose C

2013-12-01

Elevated circulating levels of branched chain and aromatic amino acids (BCAA/AAAs) are associated with insulin resistance and incident type 2 diabetes (T2D). BCAA/AAAs decrease acutely during an oral glucose tolerance test (OGTT), a diagnostic test for T2D. It is unknown whether changes in BCAA/AAAs also signal an early response to commonly used medical therapies for T2D. A liquid chromatography-mass spectrometry approach was used to measure BCAA/AAAs in 30 insulin sensitive (IS) and 30 insulin resistant (IR) subjects before and after: (1) one dose of a sulfonylurea medication, glipizide, 5 mg orally; (2) two days of twice daily metformin 500 mg orally; and (3) a 75-g OGTT. Percent change in BCAA/AAAs was determined after each intervention. Following glipizide, which increased insulin and decreased glucose in both subject groups, BCAA/AAAs decreased in the IS subjects only (all P<0.05). Following metformin, which decreased glucose and insulin in only the IR subjects, 4 BCAA/AAAs increased in the IR subjects at or below P=0.05, and none changed in the IS subjects. Following OGTT, which increased glucose and insulin in all subjects, BCAA/AAAs decreased in all subjects (P<0.05). BCAA/AAAs changed acutely during glipizide and metformin administration, and the magnitude and direction of change differed by the insulin resistance status of the individual and the intervention. These results indicate that BCAA/AAAs may be useful biomarkers for monitoring the early response to therapeutic interventions for T2D. © 2013.

Branched chain and aromatic amino acids change acutely following two medical therapies for type 2 diabetes mellitus

PubMed Central

Walford, Geoffrey A.; Davis, Jaclyn; Warner, A. Sofia; Ackerman, Rachel J.; Billings, Liana K.; Chamarthi, Bindu; Fanelli, Rebecca R.; Hernandez, Alicia M.; Huang, Chunmei; Khan, Sabina Q.; Littleton, Katherine R.; Lo, Janet; McCarthy, Rita M.; Rhee, Eugene P.; Deik, Amy; Stolerman, Elliot; Taylor, Andrew; Hudson, Margo S.; Wang, Thomas J.; Altshuler, David; Grant, Richard W.; Clish, Clary B.; Gerszten, Robert E.; Florez, Jose C.

2013-01-01

Objective Elevated circulating levels of branched chain and aromatic amino acids (BCAA/AAAs) are associated with insulin resistance and incident type 2 diabetes (T2D). BCAA/AAAs decrease acutely during an oral glucose tolerance test (OGTT), a diagnostic test for T2D. It is unknown whether changes in BCAA/AAAs also signal an early response to commonly used medical therapies for T2D. Materials and Methods A liquid chromatography-mass spectrometry approach was used to measure BCAA/AAAs in 30 insulin sensitive (IS) and 30 insulin resistant (IR) subjects before and after: 1) one dose of a sulfonylurea medication, glipizide, 5 mg orally; 2) two days of twice daily metformin 500 mg orally; and 3) a 75-gram OGTT. Percent change in BCAA/AAAs was determined after each intervention. Results Following glipizide, which increased insulin and decreased glucose in both subject groups, BCAA/AAAs decreased in the IS subjects only (all P<0.05). Following metformin, which decreased glucose and insulin in only the IR subjects, 4 BCAA/AAAs increased in the IR subjects at or below P=0.05, and none changed in the IS subjects. Following OGTT, which increased glucose and insulin in all subjects, BCAA/AAAs decreased in all subjects (P<0.05). Conclusions BCAA/AAAs changed acutely during glipizide and metformin administration, and the magnitude and direction of change differed by the insulin resistance status of the individual and the intervention. These results indicate that BCAA/AAAs may be useful biomarkers for monitoring the early response to therapeutic interventions for T2D. PMID:23953891

Enhancing human-animal relationships through veterinary medical instruction in animal-assisted therapy and animal-assisted activities.

PubMed

Schaffer, Caroline Brunsman

2008-01-01

Instruction in animal-assisted therapy (AAT) and animal-assisted activities (AAAs) teaches veterinary medical students to confidently and assertively maximize the benefits and minimize the risks of this union of animals and people. Instruction in AAT/AAA also addresses requirements by the American Veterinary Medical Association Council on Education that accredited schools/colleges of veterinary medicine include in their standard curriculum the topics of the human-animal bond, behavior, and the contributions of the veterinarian to the overall public and professional health care teams. Entry-level veterinarians should be prepared to: (1) assure that animals who provide AAT/AAA are healthy enough to visit nursing homes, hospitals, or other institutions; (2) promote behavior testing that selects animals who will feel safe, comfortable, and connected; (3) advise facilities regarding infection control and ways to provide a safe environment where the animals, their handlers, and the people being visited will not be injured or become ill; and (4) advocate for their patients and show compassion for their clients when animals are determined to be inappropriate participants in AAT/AAA programs. This article presents AAT/AAA terminology, ways in which veterinarians can advocate for AAT/AAA, the advantages of being involved in AAT/AAA, a model AAT/AAA practicum from Tuskegee University's School of Veterinary Medicine (TUSVM), and examples of co-curricular activities in AAT/AAA by TUSVM's student volunteers.

Lipoprotein(a) Levels in Patients With Abdominal Aortic Aneurysm.

PubMed

Kotani, Kazuhiko; Sahebkar, Amirhossein; Serban, Maria-Corina; Ursoniu, Sorin; Mikhailidis, Dimitri P; Mariscalco, Giovanni; Jones, Steven R; Martin, Seth; Blaha, Michael J; Toth, Peter P; Rizzo, Manfredi; Kostner, Karam; Rysz, Jacek; Banach, Maciej

2017-02-01

Circulating markers relevant to the development of abdominal aortic aneurysm (AAA) are currently required. Lipoprotein(a), Lp(a), is considered a candidate marker associated with the presence of AAA. The present meta-analysis aimed to evaluate the association between circulating Lp(a) levels and the presence of AAA. The PubMed-based search was conducted up to April 30, 2015, to identify the studies focusing on Lp(a) levels in patients with AAA and controls. Quantitative data synthesis was performed using a random effects model, with standardized mean difference (SMD) and 95% confidence interval (CI) as summary statistics. Overall, 9 studies were identified. After a combined analysis, patients with AAA were found to have a significantly higher level of Lp(a) compared to the controls (SMD: 0.87, 95% CI: 0.41-1.33, P < .001). This result remained robust in the sensitivity analysis, and its significance was not influenced after omitting each of the included studies from the meta-analysis. The present meta-analysis confirmed a higher level of circulating Lp(a) in patients with AAA compared to controls. High Lp(a) levels can be associated with the presence of AAA, and Lp(a) may be a marker in screening for AAA. Further studies are needed to establish the clinical utility of measuring Lp(a) in the prevention and management of AAA.

Understanding the molecular mechanism of aryl acylamidase activity of acetylcholinesterase - An in silico study.

PubMed

Chinnadurai, Raj Kumar; Saravanaraman, Ponne; Boopathy, Rathanam

2015-08-15

Acetylcholinesterase (AChE) exhibits two different activities, namely esterase and aryl acylamidase (AAA). Unlike esterase, AAA activity of AChE is inhibited by the active site inhibitors while remaining unaffected by the peripheral anionic site inhibitors. This differential inhibitory pattern of active and peripheral anionic site inhibitors on the AAA activity remains unanswered. To answer this, we investigated the mechanism of binding and trafficking of AAA substrates using in silico tools. Molecular docking of serotonin and AAA substrates (o-nitroacetanilide, and o-nitrotrifluoroacetanilide,) onto AChE shows that these compounds bind at the side door of AChE. Thus, we conceived that the AAA substrates prefer the side door to reach the active site for their catalysis. Further, steered molecular dynamics simulations show that the force required for binding and trafficking of the AAA substrate through the side door is comparatively lesser than their dissociation (900kJ/mol/nm). Among the two substrates, o-nitrotrifluoroacetanilide required lesser force (380kJ/mol/nm) than o-nitroacetanilide the (550kJ/mol/nm) for its binding, thus validating o-nitrotrifluoroacetanilide as a better substrate. With these observations, we resolve that the AAA activity of AChE is mediated through its side door. Therefore, binding of PAS inhibitors at the main door of AChE remain ineffective against AAA activity. Copyright © 2015 Elsevier Inc. All rights reserved.

Introducing AAA-MS, a rapid and sensitive method for amino acid analysis using isotope dilution and high-resolution mass spectrometry.

PubMed

Louwagie, Mathilde; Kieffer-Jaquinod, Sylvie; Dupierris, Véronique; Couté, Yohann; Bruley, Christophe; Garin, Jérôme; Dupuis, Alain; Jaquinod, Michel; Brun, Virginie

2012-07-06

Accurate quantification of pure peptides and proteins is essential for biotechnology, clinical chemistry, proteomics, and systems biology. The reference method to quantify peptides and proteins is amino acid analysis (AAA). This consists of an acidic hydrolysis followed by chromatographic separation and spectrophotometric detection of amino acids. Although widely used, this method displays some limitations, in particular the need for large amounts of starting material. Driven by the need to quantify isotope-dilution standards used for absolute quantitative proteomics, particularly stable isotope-labeled (SIL) peptides and PSAQ proteins, we developed a new AAA assay (AAA-MS). This method requires neither derivatization nor chromatographic separation of amino acids. It is based on rapid microwave-assisted acidic hydrolysis followed by high-resolution mass spectrometry analysis of amino acids. Quantification is performed by comparing MS signals from labeled amino acids (SIL peptide- and PSAQ-derived) with those of unlabeled amino acids originating from co-hydrolyzed NIST standard reference materials. For both SIL peptides and PSAQ standards, AAA-MS quantification results were consistent with classical AAA measurements. Compared to AAA assay, AAA-MS was much faster and was 100-fold more sensitive for peptide and protein quantification. Finally, thanks to the development of a labeled protein standard, we also extended AAA-MS analysis to the quantification of unlabeled proteins.

Association of statin prescription with small abdominal aortic aneurysm progression

PubMed Central

Ferguson, Craig D.; Clancy, Paula; Bourke, Bernard; Walker, Philip J.; Dear, Anthony; Buckenham, Tim; Norman, Paul; Golledge, Jonathan

2009-01-01

Background Statins have been suggested to reduce expansion of abdominal aortic aneurysms (AAA) independent of lipid lowering effects. Methods We assessed the association of statin treatment and serum low density lipoprotein (LDL) concentrations with small AAA expansion. 652 patients undergoing surveillance of small AAAs were entered into the study from five vascular centers. In a subset fasting lipids (n=451) and other biomarkers (n=216) were measured. AAA diameter was followed by ultrasound surveillance for a median of 5 years. Results 349 (54%) of the patients were prescribed statins. Adjusting for other risk factors statin prescription was not associated with AAA growth (odds ratio, OR, 1.23, 95% confidence interval, CI, 0.86–1.76). Above median AAA growth was positively associated with initial diameter (OR 1.78 per 4.35mm larger initial aortic diameter, 95% CI 1.49–2.14) and negatively associated with diabetes (OR 0.37, 95% CI 0.22–0.62). Above median serum LDL concentration was not associated with AAA growth. Patients receiving statins had lower serum C-reactive protein concentrations but similar matrix metalloproteinase-9 and interleukin-6 concentrations to those not prescribed these medications. Conclusions We found no association between statin prescription or LDL concentration with AAA expansion. The results do not support the findings of smaller studies and suggest that statins may have no benefit in reducing AAA progression. PMID:20152231

The Antiaircraft Journal. Volume 95, Number 2, March-April 1952

DTIC Science & Technology

1952-04-01

Command, Yoko- hama. Breuning, E. G., Far East Command, Yoko- hama Cacchiotti, Ralph R., 31st AAA Brig., Ft Lewis, Wash. Colbert , Edward F., 197th AAA Gp...Wilbur B., 47th AAA Brig., Cp Stew- art, Ga. Frick, Edwin J., 336th AAA Gun Bn, Cp Ed- wards. Mass. Gildon, Milo E., USA Alaska, Fort Richard- son

Chinese Herbal Medicine as a Potential Treatment of Abdominal Aortic Aneurysm

PubMed Central

Seto, Sai Wang; Chang, Dennis; Kiat, Hosen; Wang, Ning; Bensoussan, Alan

2018-01-01

Abdominal aortic aneurysm (AAA) is an irreversible condition where the abdominal aorta is dilated leading to potentially fatal consequence of aortic rupture. Multiple mechanisms are involved in the development and progression of AAA, including chronic inflammation, oxidative stress, vascular smooth muscle (VSMC) apoptosis, immune cell infiltration and extracellular matrix (ECM) degradation. Currently surgical therapies, including minimally invasive endovascular aneurysm repair (EVAR), are the only viable interventions for AAAs. However, these treatments are not appropriate for the majority of AAAs, which measure <50 mm. Substantial effort has been invested to identify and develop pharmaceutical treatments such as statins and doxycycline for this potentially lethal condition but these interventions failed to offer a cure or to retard the progression of AAA. Chinese herbal medicine (CHM) has been used for the management of cardiovascular diseases for thousands of years in China and other Asian countries. The unique multi-component and multi-target property of CHMs makes it a potentially ideal therapy for multifactorial diseases such as AAA. In this review, we review the current scientific evidence to support the use of CHMs for the treatment of AAA. Mechanisms of action underlying the effects of CHMs on AAA are also discussed. PMID:29732374

Homocysteine Level and Risk of Abdominal Aortic Aneurysm: A Meta-Analysis

PubMed Central

Cao, Hui; Hu, Xinhua; Zhang, Qiang; Li, Jun; Wang, Junpeng; Shao, Yang; Liu, Bing; Xin, Shijie

2014-01-01

Objectives Previous studies have reported inconsistent findings regarding the association between elevated plasma homocysteine (Hcy) levels and abdominal aortic aneurysm (AAA). We investigated this association between Hcy levels in patients with AAA and unaffected controls by conducting a meta-analysis and systematic review. Methods We conducted a systematic literature search (up to August 2013) of the PubMed database and Embase. We selected observational studies that evaluated Hcy levels in subjects with AAA compared to unaffected controls. Criteria for inclusion were the assessment of baseline Hcy and risk of AAA as an outcome. The results were presented as odd ratio (OR) and corresponding 95% confidence intervals (CI) comparing AAA patients to the control subjects. Results 7 studies with 6,445 participants were identified and analyzed. Overall, elevated plasma Hcy was associated with an increased risk of AAA (3.29; 95% CI 1.66–6.51). The pooled adjusted OR from a random effect model of only men participants in the AAA compared with the control group was 2.36 (95% CI 0.63–8.82). Conclusion This meta-analysis and systematic review suggested that Hcy significantly increased the risk of AAA. PMID:24465733

Chinese Herbal Medicine as a Potential Treatment of Abdominal Aortic Aneurysm.

PubMed

Seto, Sai Wang; Chang, Dennis; Kiat, Hosen; Wang, Ning; Bensoussan, Alan

2018-01-01

Abdominal aortic aneurysm (AAA) is an irreversible condition where the abdominal aorta is dilated leading to potentially fatal consequence of aortic rupture. Multiple mechanisms are involved in the development and progression of AAA, including chronic inflammation, oxidative stress, vascular smooth muscle (VSMC) apoptosis, immune cell infiltration and extracellular matrix (ECM) degradation. Currently surgical therapies, including minimally invasive endovascular aneurysm repair (EVAR), are the only viable interventions for AAAs. However, these treatments are not appropriate for the majority of AAAs, which measure <50 mm. Substantial effort has been invested to identify and develop pharmaceutical treatments such as statins and doxycycline for this potentially lethal condition but these interventions failed to offer a cure or to retard the progression of AAA. Chinese herbal medicine (CHM) has been used for the management of cardiovascular diseases for thousands of years in China and other Asian countries. The unique multi-component and multi-target property of CHMs makes it a potentially ideal therapy for multifactorial diseases such as AAA. In this review, we review the current scientific evidence to support the use of CHMs for the treatment of AAA. Mechanisms of action underlying the effects of CHMs on AAA are also discussed.

Mitochondrial ATAD3A regulates milk biosynthesis and proliferation of mammary epithelial cells from dairy cow via the mTOR pathway.

PubMed

Chen, Dongying; Yuan, Xiaohan; Liu, Lijie; Zhang, Minghui; Qu, Bo; Zhen, Zhen; Gao, Xuejun

2018-05-01

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein, which is essential for cell growth and metabolism. The mechanism by which ATAD3A acts is still not fully understood. In this study, we explored the regulatory role of ATAD3A on milk biosynthesis and proliferation of bovine mammary epithelial cell. We showed that ATAD3A is localized in mitochondria and the expression of ATAD3A was up-regulated in response to extracellular stimuli such as amino acids and hormones. We observed that ATAD3A positively regulated milk protein, fat, and lactose biosynthesis, and cell proliferation. We further revealed that ATAD3A promoted the expressions of mTOR, SREBP-1c, and Cyclin D1, and triggers mTOR phosphorylation. In summary, our data reveal that ATAD3A regulates the mTOR, SREBP-1c, and Cyclin D1 signaling pathways for milk biosynthesis and cell proliferation. © 2018 International Federation for Cell Biology.

Operational Plasticity Enables Hsp104 to Disaggregate Diverse Amyloid and Non-Amyloid Clients

PubMed Central

DeSantis, Morgan E.; Leung, Eunice H.; Sweeny, Elizabeth A.; Jackrel, Meredith E.; Cushman-Nick, Mimi; Neuhaus-Follini, Alexandra; Vashist, Shilpa; Sochor, Matthew A.; Knight, M. Noelle; Shorter, James

2012-01-01

Summary It is not understood how Hsp104, a hexameric AAA+ ATPase from yeast, disaggregates diverse structures including stress-induced aggregates, prions, and α-synuclein conformers connected to Parkinson disease. Here, we establish that Hsp104 hexamers adapt different mechanisms of intersubunit collaboration to disaggregate stress-induced aggregates versus amyloid. To resolve disordered aggregates, Hsp104 subunits collaborate non-co-operatively via probabilistic substrate binding and ATP hydrolysis. To disaggregate amyloid, several subunits co-operatively engage substrate and hydrolyze ATP. Importantly, Hsp104 variants with impaired intersubunit communication dissolve disordered aggregates but not amyloid. Unexpectedly, prokaryotic ClpB subunits collaborate differently than Hsp104 and couple probabilistic substrate binding to cooperative ATP hydrolysis, which enhances disordered aggregate dissolution but sensitizes ClpB to inhibition and diminishes amyloid disaggregation. Finally, we establish that Hsp104 hexamers deploy more subunits to disaggregate Sup35 prion strains with more stable ‘cross-β’ cores. Thus, operational plasticity enables Hsp104 to robustly dissolve amyloid and non-amyloid clients, which impose distinct mechanical demands. PMID:23141537

Chromosome Synapsis Alleviates Mek1-Dependent Suppression of Meiotic DNA Repair

PubMed Central

Subramanian, Vijayalakshmi V.; MacQueen, Amy J.; Vader, Gerben; Shinohara, Miki; Sanchez, Aurore; Borde, Valérie; Shinohara, Akira; Hochwagen, Andreas

2016-01-01

Faithful meiotic chromosome segregation and fertility require meiotic recombination between homologous chromosomes rather than the equally available sister chromatid, a bias that in Saccharomyces cerevisiae depends on the meiotic kinase, Mek1. Mek1 is thought to mediate repair template bias by specifically suppressing sister-directed repair. Instead, we found that when Mek1 persists on closely paired (synapsed) homologues, DNA repair is severely delayed, suggesting that Mek1 suppresses any proximal repair template. Accordingly, Mek1 is excluded from synapsed homologues in wild-type cells. Exclusion requires the AAA+-ATPase Pch2 and is directly coupled to synaptonemal complex assembly. Stage-specific depletion experiments further demonstrate that DNA repair in the context of synapsed homologues requires Rad54, a repair factor inhibited by Mek1. These data indicate that the sister template is distinguished from the homologue primarily by its closer proximity to inhibitory Mek1 activity. We propose that once pairing or synapsis juxtaposes homologues, exclusion of Mek1 is necessary to avoid suppression of all templates and accelerate repair progression. PMID:26870961

Comparative analysis of activator-Eσ54 complexes formed with nucleotide-metal fluoride analogues

PubMed Central

Burrows, Patricia C.; Joly, Nicolas; Nixon, B. Tracy; Buck, Martin

2009-01-01

Bacterial RNA polymerase (RNAP) containing the major variant σ54 factor forms open promoter complexes in a reaction in which specialized activator proteins hydrolyse ATP. Here we probe binding interactions between σ54-RNAP (Eσ54) and the ATPases associated with various cellular activities (AAA+) domain of the Escherichia coli activator protein, PspF, using nucleotide-metal fluoride (BeF and AlF) analogues representing ground and transition states of ATP, which allow complexes (that are otherwise too transient with ATP) to be captured. We show that the organization and functionality of the ADP–BeF- and ADP–AlF-dependent complexes greatly overlap. Our data support an activation pathway in which the initial ATP-dependent binding of the activator to the Eσ54 closed complex results in the re-organization of Eσ54 with respect to the transcription start-site. However, the nucleotide-dependent binding interactions between the activator and the Eσ54 closed complex are in themselves insufficient for forming open promoter complexes when linear double-stranded DNA is present in the initial closed complex. PMID:19553192

α-SNAP interferes with the zippering of the SNARE protein membrane fusion machinery.

PubMed

Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

2014-06-06

Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

TRIP13 impairs mitotic checkpoint surveillance and is associated with poor prognosis in multiple myeloma

PubMed Central

Song, Dongliang; Hu, Liangning; Xie, Bingqian; Wang, Houcai; Gao, Lu; Gao, Minjie; Xu, Hongwei; Xu, Zhijian; Wu, Xiaosong; Zhang, Yiwen; Zhu, Weiliang; Zhan, Fenghuang; Shi, Jumei

2017-01-01

AAA-ATPase TRIP13 is one of the chromosome instability gene recently established in multiple myeloma (MM), the second most common and incurable hematological malignancy. However, the specific function of TRIP13 in MM is largely unknown. Using sequential gene expression profiling, we demonstrated that high TRIP13 expression levels were positively correlated with progression, disease relapse, and poor prognosis in MM patients. Overexpressing human TRIP13 in myeloma cells prompted cell growth and drug resistance, and overexpressing murine TRIP13, which shares 93% sequence identity with human TRIP13, led to colony formation of NIH/3T3 fibroblasts in vitro and tumor formation in vivo. Meanwhile, the knockdown of TRIP13 inhibited myeloma cell growth, induced cell apoptosis, and reduced tumor burden in xenograft MM mice. Mechanistically, we observed that the overexpression of TRIP13 abrogated the spindle checkpoint and induced proteasome-mediated degradation of MAD2 primarily through the Akt pathway. Thus, our results demonstrate that TRIP13 may serve as a biomarker for MM disease development and prognosis, making it a potential target for future therapies. PMID:28157697

Lon in maintaining mitochondrial and endoplasmic reticulum homeostasis.

PubMed

Yang, Jieyeqi; Chen, Wenying; Zhang, Boyang; Tian, Fengli; Zhou, Zheng; Liao, Xin; Li, Chen; Zhang, Yi; Han, Yanyan; Wang, Yan; Li, Yuzhe; Wang, Guo-Qing; Shen, Xiao Li

2018-06-01

As a vital member of AAA+ (ATPase associated with diverse cellular activities) protein superfamily, Lon, a homo-hexameric ring-shaped protein complex with a serine-lysine catalytic dyad, is highly conserved throughout almost all prokaryotic and eukaryotic organisms. Lon protease (LONP) plays an important role in maintaining mitoproteostasis through selectively recognizing and degrading oxidatively modified mitoproteins within mitochondrial matrix, such as oxidized aconitase, phosphorylated mitochondrial transcription factor A, etc. Furthermore, the up-regulated LONP increased mitochondrial ROS generation to promote cell survival, cell proliferation, epithelial-mesenchymal transition, and cell migration, which was attributed to the up-regulation of NADH:ubiquinone oxidoreductase core subunit S8 via interaction with chaperone Lon under hypoxic or oxidative stress in tumorigenesis. In addition, Lon also participated in protein kinase RNA (PKR)-like endoplasmic reticulum kinase signaling pathway under endoplasmic reticulum (ER) stress. In short, Lon, as a pivotal stress-responsive protein that involved in the crosstalks among mitochondria, ER and nucleus, participated in multifarious important cellular processes crucial for cell survival, such as the mitochondrial protein quality control system, the mitochondrial unfolded protein response, the mtDNA maintenance, and the ER unfolded protein response.

Mechanism of One-Way Traffic of Hexameric Phi29 DNA Packaging Motor with Four Electropositive Relaying Layers Facilitating Antiparallel Revolution

PubMed Central

2013-01-01

The importance of nanomotors in nanotechnology is akin to that of mechanical engines to daily life. The AAA+ superfamily is a class of nanomotors performing various functions. Their hexagonal arrangement facilitates bottom-up assembly for stable structures. The bacteriophage phi29 DNA translocation motor contains three coaxial rings: a dodecamer channel, a hexameric ATPase ring, and a hexameric pRNA ring. The viral DNA packaging motor has been believed to be a rotational machine. However, we discovered a revolution mechanism without rotation. By analogy, the earth revolves around the sun while rotating on its own axis. One-way traffic of dsDNA translocation is facilitated by five factors: (1) ATPase changes its conformation to revolve dsDNA within a hexameric channel in one direction; (2) the 30° tilt of the channel subunits causes an antiparallel arrangement between two helices of dsDNA and channel wall to advance one-way translocation; (3) unidirectional flow property of the internal channel loops serves as a ratchet valve to prevent reversal; (4) 5′–3′ single-direction movement of one DNA strand along the channel wall ensures single direction; and (5) four electropositive layers interact with one strand of the electronegative dsDNA phosphate backbone, resulting in four relaying transitional pauses during translocation. The discovery of a riding system along one strand provides a motion nanosystem for cargo transportation and a tool for studying force generation without coiling, friction, and torque. The revolution of dsDNA among 12 subunits offers a series of recognition sites on the DNA backbone to provide additional spatial variables for nucleotide discrimination for sensing applications. PMID:23510192

Role of the σ 54 Activator Interacting Domain in Bacterial Transcription Initiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegel, Alexander R.; Wemmer, David E.

Bacterial sigma factors are subunits of RNA polymerase that direct the holoenzyme to specific sets of promoters in the genome and are a central element of regulating transcription. Most polymerase holoenzymes open the promoter and initiate transcription rapidly after binding. However, polymerase containing the members of the σ 54 family must be acted on by a transcriptional activator before DNA opening and initiation occur. A key domain in these transcriptional activators forms a hexameric AAA + ATPase that acts through conformational changes brought on by ATP hydrolysis. Contacts between the transcriptional activator and σ 54 are primarily made through anmore » N-terminal σ 54 activator interacting domain (AID). To better understand this mechanism of bacterial transcription initiation, we characterized the σ 54 AID by NMR spectroscopy and other biophysical methods and show that it is an intrinsically disordered domain in σ 54 alone. In this paper, we identified a minimal construct of the Aquifex aeolicus σ 54 AID that consists of two predicted helices and retains native-like binding affinity for the transcriptional activator NtrC1. Using the NtrC1 ATPase domain, bound with the non-hydrolyzable ATP analog ADP-beryllium fluoride, we studied the NtrC1–σ 54 AID complex using NMR spectroscopy. We show that the σ 54 AID becomes structured after associating with the core loops of the transcriptional activators in their ATP state and that the primary site of the interaction is the first predicted helix. Finally, understanding this complex, formed as the first step toward initiation, will help unravel the mechanism of σ 54 bacterial transcription initiation.« less

An AAA-DDD triply hydrogen-bonded complex easily accessible for supramolecular polymers.

PubMed

Han, Yi-Fei; Chen, Wen-Qiang; Wang, Hong-Bo; Yuan, Ying-Xue; Wu, Na-Na; Song, Xiang-Zhi; Yang, Lan

2014-12-15

For a complementary hydrogen-bonded complex, when every hydrogen-bond acceptor is on one side and every hydrogen-bond donor is on the other, all secondary interactions are attractive and the complex is highly stable. AAA-DDD (A=acceptor, D=donor) is considered to be the most stable among triply hydrogen-bonded sequences. The easily synthesized and further derivatized AAA-DDD system is very desirable for hydrogen-bonded functional materials. In this case, AAA and DDD, starting from 4-methoxybenzaldehyde, were synthesized with the Hantzsch pyridine synthesis and Friedländer annulation reaction. The association constant determined by fluorescence titration in chloroform at room temperature is 2.09×10(7)  M(-1) . The AAA and DDD components are not coplanar, but form a V shape in the solid state. Supramolecular polymers based on AAA-DDD triply hydrogen bonded have also been developed. This work may make AAA-DDD triply hydrogen-bonded sequences easily accessible for stimuli-responsive materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

LMIP/AAA: Local Authentication, Authorization and Accounting (AAA) Protocol for Mobile IP

NASA Astrophysics Data System (ADS)

Chenait, Manel

Mobile IP represents a simple and scalable global mobility solution. However, it inhibits various vulnerabilities to malicious attacks and, therefore, requires the integration of appropriate security services. In this paper, we discuss two authentication schemes suggested for Mobile IP: standard authentication and Mobile IP/AAA authentication. In order to provide Mobile IP roaming services including identity verication, we propose an improvement to Mobile/AAA authentication scheme by applying a local politic key management in each domain, hence we reduce hando latency by avoiding the involvement of AAA infrastructure during mobile node roaming.

Sex differences in abdominal aortic aneurysms.

PubMed

Boese, Austin C; Chang, Lin; Yin, Ke-Jie; Chen, Y Eugene; Lee, Jean-Pyo; Hamblin, Milton H

2018-06-01

Abdominal aortic aneurysm (AAA) is a vascular disorder with a high case fatality rate in the instance of rupture. AAA is a multifactorial disease, and the etiology is still not fully understood. AAA is more likely to occur in men, but women have a greater risk of rupture and worse prognosis. Women are reportedly protected against AAA possibly by premenopausal levels of estrogen and are, on average, diagnosed at older ages than men. Here, we review the present body of research on AAA pathophysiology in humans, animal models, and cultured cells, with an emphasis on sex differences and sex steroid hormone signaling.

SMYD2 promoter DNA methylation is associated with abdominal aortic aneurysm (AAA) and SMYD2 expression in vascular smooth muscle cells.

PubMed

Toghill, Bradley J; Saratzis, Athanasios; Freeman, Peter J; Sylvius, Nicolas; Bown, Matthew J

2018-01-01

Abdominal aortic aneurysm (AAA) is a deadly cardiovascular disease characterised by the gradual, irreversible dilation of the abdominal aorta. AAA is a complex genetic disease but little is known about the role of epigenetics. Our objective was to determine if global DNA methylation and CpG-specific methylation at known AAA risk loci is associated with AAA, and the functional effects of methylation changes. We assessed global methylation in peripheral blood mononuclear cell DNA from 92 individuals with AAA and 93 controls using enzyme-linked immunosorbent assays, identifying hyper-methylation in those with large AAA and a positive linear association with AAA diameter ( P  < 0.0001, R 2  = 0.3175).We then determined CpG methylation status of regulatory regions in genes located at AAA risk loci identified in genome-wide association studies, using bisulphite next-generation sequencing (NGS) in vascular smooth muscle cells (VSMCs) taken from aortic tissues of 44 individuals (24 AAAs and 20 controls). In IL6R , 2 CpGs were hyper-methylated ( P  = 0.0145); in ERG , 13 CpGs were hyper-methylated ( P  = 0.0005); in SERPINB9 , 6 CpGs were hypo-methylated ( P  = 0.0037) and 1 CpG was hyper-methylated ( P  = 0.0098); and in SMYD2 , 4 CpGs were hypo-methylated ( P  = 0.0012).RT-qPCR was performed for each differentially methylated gene on mRNA from the same VSMCs and compared with methylation. This analysis revealed downregulation of SMYD2 and SERPINB9 in AAA, and a direct linear relationship between SMYD2 promoter methylation and SMYD2 expression ( P  = 0.038). Furthermore, downregulation of SMYD2 at the site of aneurysm in the aortic wall was further corroborated in 6 of the same samples used for methylation and gene expression analysis with immunohistochemistry. This study is the first to assess DNA methylation in VSMCs from individuals with AAA using NGS, and provides further evidence there is an epigenetic basis to AAA. Our study shows that methylation status of the SMYD2 promoter may be linked with decreased SMYD2 expression in disease pathobiology. In support of our work, downregulated SMYD2 has previously been associated with adverse cardiovascular physiology and inflammation, which are both hallmarks of AAA. The identification of such adverse epigenetic modifications could potentially contribute towards the development of epigenetic treatment strategies in the future.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Badkul, R; Nicolai, W; Pokhrel, D

Purpose: To compare the impact of Pencil Beam(PB) and Anisotropic Analytic Algorithm(AAA) dose calculation algorithms on OARs and planning target volume (PTV) in thoracic spine stereotactic body radiation therapy (SBRT). Methods: Ten Spine SBRT patients were planned on Brainlab iPlan system using hybrid plan consisting of 1–2 non-coplanar conformal-dynamic arcs and few IMRT beams treated on NovalisTx with 6MV photon. Dose prescription varied from 20Gy to 30Gy in 5 fractions depending on the situation of the patient. PB plans were retrospectively recalculated using the Varian Eclipse with AAA algorithm using same MUs, MLC pattern and grid size(3mm).Differences in dose volumemore » parameters for PTV, spinal cord, lung, and esophagus were analyzed and compared for PB and AAA algorithms. OAR constrains were followed per RTOG-0631. Results: Since patients were treated using PB calculation, we compared all the AAA DVH values with respect to PB plan values as standard, although AAA predicts the dose more accurately than PB. PTV(min), PTV(Max), PTV(mean), PTV(D99%), PTV(D90%) were overestimated with AAA calculation on average by 3.5%, 1.84%, 0.95%, 3.98% and 1.55% respectively as compared to PB. All lung DVH parameters were underestimated with AAA algorithm mean deviation of lung V20, V10, V5, and 1000cc were 42.81%,19.83%, 18.79%, and 18.35% respectively. AAA overestimated Cord(0.35cc) by mean of 17.3%; cord (0.03cc) by 12.19% and cord(max) by 10.5% as compared to PB. Esophagus max dose were overestimated by 4.4% and 5cc by 3.26% for AAA algorithm as compared to PB. Conclusion: AAA overestimated the PTV dose values by up to 4%.The lung DVH had the greatest underestimation of dose by AAA versus PB. Spinal cord dose was overestimated by AAA versus PB. Given the critical importance of accuracy of OAR and PTV dose calculation for SBRT spine, more accurate algorithms and validation of calculated doses in phantom models are indicated.« less

Flow stagnation volume and abdominal aortic aneurysm growth: Insights from patient-specific computational flow dynamics of Lagrangian-coherent structures.

PubMed

Joly, Florian; Soulez, Gilles; Garcia, Damien; Lessard, Simon; Kauffmann, Claude

2018-01-01

Abdominal aortic aneurysms (AAA) are localized, commonly-occurring dilations of the aorta. When equilibrium between blood pressure (loading) and wall mechanical resistance is lost, rupture ensues, and patient death follows, if not treated immediately. Experimental and numerical analyses of flow patterns in arteries show direct correlations between wall shear stress and wall mechano-adaptation with the development of zones prone to thrombus formation. For further insights into AAA flow topology/growth interaction, a workout of patient-specific computational flow dynamics (CFD) is proposed to compute finite-time Lyapunov exponents and extract Lagrangian-coherent structures (LCS). This computational model was first compared with 4-D phase-contrast magnetic resonance imaging (MRI) in 5 patients. To better understand the impact of flow topology and transport on AAA growth, hyperbolic, repelling LCS were computed in 1 patient during 8-year follow-up, including 9 volumetric morphologic AAA measures by computed tomography-angiography (CTA). LCS defined barriers to Lagrangian jet cores entering AAA. Domains enclosed between LCS and the aortic wall were considered to be stagnation zones. Their evolution was studied during AAA growth. Good correlation - 2-D cross-correlation coefficients of 0.65, 0.86 and 0.082 (min, max, SD) - was obtained between numerical simulations and 4-D MRI acquisitions in 6 specific cross-sections from 4 patients. In follow-up study, LCS divided AAA lumens into 3 dynamically-isolated zones: 2 stagnation volumes lying in dilated portions of the AAA, and circulating volume connecting the inlet to the outlet. The volume of each zone was tracked over time. Although circulating volume remained unchanged during 8-year follow-up, the AAA lumen and main stagnation zones grew significantly (8 cm 3 /year and 6 cm 3 /year, respectively). This study reveals that transient transport topology can be quantified in patient-specific AAA during disease progression by CTA, in parallel with lumen morphology. It is anticipated that analysis of the main AAA stagnation zones by patient-specific CFD on a yearly basis could help to predict AAA growth and rupture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional Differentiation of SWI/SNF Remodelers in Transcription and Cell Cycle Control▿ †

PubMed Central

Moshkin, Yuri M.; Mohrmann, Lisette; van Ijcken, Wilfred F. J.; Verrijzer, C. Peter

2007-01-01

Drosophila BAP and PBAP represent two evolutionarily conserved subclasses of SWI/SNF chromatin remodelers. The two complexes share the same core subunits, including the BRM ATPase, but differ in a few signature subunits: OSA defines BAP, whereas Polybromo (PB) and BAP170 specify PBAP. Here, we present a comprehensive structure-function analysis of BAP and PBAP. An RNA interference knockdown survey revealed that the core subunits BRM and MOR are critical for the structural integrity of both complexes. Whole-genome expression profiling suggested that the SWI/SNF core complex is largely dysfunctional in cells. Regulation of the majority of target genes required the signature subunit OSA, PB, or BAP170, suggesting that SWI/SNF remodelers function mostly as holoenzymes. BAP and PBAP execute similar, independent, or antagonistic functions in transcription control and appear to direct mostly distinct biological processes. BAP, but not PBAP, is required for cell cycle progression through mitosis. Because in yeast the PBAP-homologous complex, RSC, controls cell cycle progression, our finding reveals a functional switch during evolution. BAP mediates G2/M transition through direct regulation of string/cdc25. Its signature subunit, OSA, is required for directing BAP to the string/cdc25 promoter. Our results suggest that the core subunits play architectural and enzymatic roles but that the signature subunits determine most of the functional specificity of SWI/SNF holoenzymes in general gene control. PMID:17101803

Attenuation of aortic aneurysms with stem cells from different genders.

PubMed

Davis, John P; Salmon, Morgan; Pope, Nicolas H; Lu, Guanyi; Su, Gang; Sharma, Ashish K; Ailawadi, Gorav; Upchurch, Gilbert R

2015-11-01

No medical therapies are yet available to slow abdominal aortic aneurysm (AAA) growth. This study sought to investigate the effect of different genders of bone marrow-derived mesenchymal stem cells (MSC) on AAA growth in a murine AAA model. Given the decreased rate of AAA in women, it is hypothesized that female MSC would attenuate AAA growth more so than male MSC. Aortas of 8-10-wk-old male C57Bl/6 mice were perfused with purified porcine pancreatic elastase to induce AAA formation. Bone marrow-derived MSC from male and female mice were dosed via tail vein injection (3 million cells per dose, 500 μL of volume per injection) on postaortic perfusion days 1, 3, and 5. Aortas were harvested after 14 d. Mean aortic dilation in the elastase group was 121 ± 5.2% (mean ± standard error of the mean), while male MSC inhibited AAA growth (87.8 ± 6.9%, P = 0.008) compared with that of elastase. Female MSC showed the most marked attenuation of AAA growth (75.2 ± 8.3% P = 0.0004). Proinflammatory cytokines tumor necrosis factor α, interleukin 1β, and monocyte chemotactic protein-1 (MCP-1) were only decreased in tissues treated with female MSC (P = 0.017, P = 0.001, and P < 0.0001, respectively, when compared with elastase). These data exhibit that female MSC more strongly attenuate AAA growth in the murine model. Furthermore, female MSC and male MSC inhibit proinflammatory cytokines at varying levels. The effects of MSC on aortic tissue offer a promising insight into biologic therapies for future medical treatment of AAAs in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

Clinical Efficacy of Transthoracic Echocardiography for Screening Abdominal Aortic Aneurysm in Turkish Patients.

PubMed

Kilic, Salih; Saracoglu, Erhan; Cekici, Yusuf

2018-03-01

The objective of this study was to investigate the prevalence of abdominal aortic aneurysm (AAA) in Turkish patients aged ≥ 65 years, and to demonstrate the applicability of echocardiography to AAA screening. Transthoracic echocardiography (TTE) was performed in all consecutive patients aged ≥ 65 years who were referred to cardiology clinics or were referred from other outpatient clinics. The abdominal aorta (AA) of each patient was scanned using the same probe, and the time spent was recorded. Demographic and clinic characteristics of the patients were recorded at the end of the echocardiography. Among 1948 patients (mean age 70.9 ± 6 years; 49.8% male), the AA was visualized in 96.3%. AAA was identified in 3.7% (69/1878) of the patients, of whom AAA was previously known in 20.3% (n = 14). The prevalence of unknown AAA was 2.93%. The average time needed to scan and measure the AA was 1 minute and 3 seconds (±23 seconds). Aortic root diameters were significantly higher in the patients with AAA than in those without AAA (34.7 ± 4.2 vs. 29.8 ± 4.7; p < 0.001). Age (per 1 year increase) [odds ratio (OR), 1.245; p < 0.001], male gender (OR, 5.382; p < 0.001), smoking (OR, 2.118; p = 0.037), and aortic root diameter (per 1 mm increase) (OR, 1.299; p < 0.001) were independent predictors of AAA. This study is important in that it showed a high prevalence of AAA in Turkish patients aged ≥ 65 years, and demonstrated that AAA can be visualized in the majority of patients in as little as 1 minute during TTE.

Identification of a genetic variant associated with abdominal aortic aneurysms on chromosome 3p12.3 by genome wide association.

PubMed

Elmore, James R; Obmann, Melissa A; Kuivaniemi, Helena; Tromp, Gerard; Gerhard, Glenn S; Franklin, David P; Boddy, Amy M; Carey, David J

2009-06-01

The goal of this project was to identify genetic variants associated with abdominal aortic aneurysms (AAAs). A genome wide association study was carried out using pooled DNA samples from 123 AAA cases and 112 controls matched for age, gender, and smoking history using Affymetrix 500K single nucleotide polymorphism (SNP) arrays (Affymetrix, Inc, Santa Clara, Calif). The difference in mean allele frequency between cases and controls was calculated for each SNP and used to identify candidate genomic regions. Association of candidate SNPs with AAA was confirmed by individual TaqMan genotype assays in a total of 2096 cases and controls that included an independent replication sample set. A genome wide association study of AAA cases and controls identified a candidate AAA-associated haplotype on chromosome 3p12.3. By individual genotype analysis, four SNPs in this region were significantly associated with AAA in cases and controls from the original study population. One SNP in this region (rs7635818) was genotyped in a total of 502 cases and 736 controls from the original study population (P = .017) and 448 cases and 410 controls from an independent replication sample (P = .013; combined P value = .0028; combined odds ratio [OR] = 1.33). An even stronger association with AAA was observed in a subset of smokers (391 cases, 241 controls, P = .00041, OR = 1.80), which represent the highest risk group for AAA. The AAA-associated haplotype is located approximately 200 kbp upstream of the CNTN3 gene transcription start site. This study identifies a region on chromosome 3 that is significantly associated with AAA in 2 distinct study populations.

Inhibition of endoplasmic reticulum stress by intermedin1-53 attenuates angiotensin II-induced abdominal aortic aneurysm in ApoE KO Mice.

PubMed

Ni, Xian-Qiang; Lu, Wei-Wei; Zhang, Jin-Sheng; Zhu, Qing; Ren, Jin-Ling; Yu, Yan-Rong; Liu, Xiu-Ying; Wang, Xiu-Jie; Han, Mei; Jing, Qing; Du, Jie; Tang, Chao-Shu; Qi, Yong-Fen

2018-06-26

Endoplasmic reticulum stress (ERS) is involved in the development of abdominal aortic aneurysm (AAA). Since bioactive peptide intermedin (IMD)1-53 protects against AAA formation, here we investigated whether IMD1-53 attenuates AAA by inhibiting ERS. AAA model was induced by angiotensin II (AngII) in ApoE KO mouse background. AngII-treated mouse aortas showed increased ERS gene transcription of caspase12, eukaryotic translation initiation factor 2a (eIf2a) and activating transcription factor 4(ATF4).The protein level of ERS marker glucose regulated protein 94(GRP94), ATF4 and C/EBP homologous protein 10(CHOP) was also up-regulated by AngII. Increased ERS levels were accompanied by severe VSMC apoptosis in human AAA aorta. In vivo administration of IMD1-53 greatly reduced AngII-induced AAA and abrogated the activation of ERS. To determine whether IMD inhibited AAA by ameliorating ERS, we used 2 non-selective ERS inhibitors phenyl butyrate (4-PBA) and taurine (TAU). Similar to IMD, PBA, and TAU significantly reduced the incidence of AAA and AAA-related pathological disorders. In vitro, AngII infusion up-regulated CHOP, caspase12 expression and led to VSMC apoptosis. IMD siRNA aggravated the CHOP, caspase12-mediated VSMC apoptosis, which was abolished by ATF4 silencing. IMD infusion promoted the phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in aortas in ApoE KO mice, and the AMPK inhibitor compound C abolished the protective effect of IMD on VSMC ERS and apoptosis induced by AngII. In conclusion, IMD may protect against AAA formation by inhibiting ERS via activating AMPK phosphorylation.

Geometric analysis of ruptured and nonruptured abdominal aortic aneurysms.

PubMed

Kimura, Masaru; Hoshina, Katsuyuki; Miyahara, Kazuhiro; Nitta, Jun; Kobayashi, Masaharu; Yamamoto, Sota; Ohshima, Marie

2018-06-15

The objective of this study was to use parameters to determine the geometric differences between ruptured abdominal aortic aneurysms (AAAs) and nonruptured AAAs. Computed tomography data of 38 ruptured AAAs and 215 electively repaired (nonruptured) AAAs were collected from multiple institutes. We compared the ruptured AAA group and nonruptured AAA group with 1:1 matching by using the Mahalanobis distance, which was calculated using the patient's age, sex, and AAA diameter. We selected the longitudinal AAA image in multiplanar reconstruction view, placed a hypothetical ellipse on the aneurysm's protruded curve, and placed a circle on the portion connecting the aneurysm and the aorta. We then measured the aspect ratio (the vertical diameter divided by the horizontal diameter) and fillet radius (the radius of arc). The aspect ratio was significantly lower in the ruptured group than in the nonruptured group (2.02 ± 0.53 vs 2.60 ± 1.02; P = .002), as was the fillet radius (0.28 ± 0.18 vs 0.81 ± 0.44; P < .001). Receiver operating characteristic analysis revealed that the area under the curve of the aspect ratio was 0.688, and the optimal cutoff point was 2.23, with sensitivity and specificity of 0.55 and 0.76, respectively. The area under the curve of the fillet radius was 0.933, and the optimal cutoff was 0.347, with sensitivity and specificity of 0.97 and 0.87, respectively. The geometric analysis performed in this study revealed that ruptured AAAs had a smaller fillet radius and smaller aspect ratio than nonruptured AAAs did. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Plasma D-dimer as a predictor of the progression of abdominal aortic aneurysm.

PubMed

Vele, E; Kurtcehajic, A; Zerem, E; Maskovic, J; Alibegovic, E; Hujdurovic, A

2016-11-01

Essentials D-dimer could provide important information about abdominal aortic aneurysm (AAA) progression. The greatest diameter of the infrarenal aorta and the value of plasma D-dimer were determined. AAA progression is correlated with increasing plasma D-dimer levels. The increasing value of plasma D-dimer could be a predictor of aneurysm progression. Background The natural course of abdominal aortic aneurysm (AAA) is mostly asymptomatic and unpredictable. D-dimer could provide potentially important information about subsequent AAA progression. Objectives The aims of this study were to establish the relationship between the progression of an abdominal aortic aneurysm (AAA) and plasma D-dimer concentration over a 12-month period and determine the value of plasma D-dimer in patients with sub-aneurysmal aortic dilatation. Patients/Methods This was a prospective observational study that involved 33 patients with an AAA, 30 patients with sub-aneurysmal aortic dilatation and 30 control subjects. The greatest diameter of the infrarenal aorta, which was assessed by ultrasound, and the value of plasma D-dimer were determined for all subjects at baseline assessment, as well as after 12 months for those with an AAA. Results A positive correlation was found between the diameter of an AAA and plasma D-dimer concentration at the baseline and the control measurement stages. There was a strong positive correlation between AAA progression and increasing plasma D-dimer concentration over a 12-month period. Among patients with sub-aneurysmal aortic dilatation (n = 30), the value of plasma D-dimer was higher compared with matched controls (n = 30). Conclusions There is a strongly positive correlation between AAA progression and increasing plasma D-dimer concentration. The value of plasma D-dimer is higher in patients with sub-aneurysmal aortic dilatation than in control subjects. © 2016 International Society on Thrombosis and Haemostasis.

Variation in Death Rate After Abdominal Aortic Aneurysmectomy in the United States

PubMed Central

Dimick, Justin B.; Stanley, James C.; Axelrod, David A.; Kazmers, Andris; Henke, Peter K.; Jacobs, Lloyd A.; Wakefield, Thomas W.; Greenfield, Lazar J.; Upchurch, Gilbert R.

2002-01-01

Objective To determine whether high-volume hospitals (HVHs) have lower in-hospital death rates after abdominal aortic aneurysm (AAA) repair compared with low-volume hospitals (LVHs). Summary Background Data Select statewide studies have shown that HVHs have superior outcomes compared with LVHs for AAA repair, but they may not be representative of the true volume–outcome relationship for the entire United States. Methods Patients undergoing repair of intact or ruptured AAAs in the Nationwide Inpatient Sample (NIS) for 1996 and 1997 were included (n = 13,887) for study. The NIS represents a 20% stratified random sample representative of all U.S. hospitals. Unadjusted and case mix-adjusted analyses were performed. Results The overall death rate was 3.8% for intact AAA repair and 47% for ruptured AAA repair. For repair of intact AAAs, HVHs had a lower death rate than LVHs. The death rate after repair of ruptured AAA was also slightly lower at HVHs. In a multivariate analysis adjusting for case mix, having surgery at an LVH was associated with a 56% increased risk of in-hospital death. Other independent risk factors for in-hospital death included female gender, age older than 65 years, aneurysm rupture, urgent or emergent admission, and comorbid disease. Conclusions This study from a representative national database documents that HVHs have a significantly lower death rate than LVHs for repair of both intact and ruptured AAA. These data support the regionalization of patients to HVHs for AAA repair. PMID:11923615

Comparison of Conscious Sedation and Asleep-Awake-Asleep Techniques for Awake Craniotomy.

PubMed

Dilmen, Ozlem Korkmaz; Akcil, Eren Fatma; Oguz, Abdulvahap; Vehid, Hayriye; Tunali, Yusuf

2017-01-01

Since awake craniotomy (AC) has become a standard of care for supratentorial tumour resection, especially in the motor and language cortex, determining the most appropriate anaesthetic protocol is very important. The aim of this retrospective study is to compare the effectiveness of conscious sedation (CS) to "awake-asleep-awake" (AAA) techniques for supratentorial tumour resection. Forty-two patients undergoing CS and 22 patients undergoing AAA were included in the study. The primary endpoint was to compare the CS and AAA techniques with respect to intraoperative pain and agitation in patients undergoing supratentorial tumour resection. The secondary endpoint was comparison of the other intraoperative complications. This study results show that the incidence of intraoperative agitation and seizure were lower in the AAA group than in the CS group. Intraoperative blood pressures were significantly higher in the CS group than in the AAA group during the pinning and incision, but the level of blood pressures did not need antihypertensive treatment. Otherwise, blood pressures were significantly higher in the AAA group than in the CS group during the neurological examination and the severity of hypertension needed statistically significant more antihypertensive treatment in the AAA group. As a result of hypertension, the amount of intraoperative bleeding was higher in the AAA group than in the CS group. In conclusion, the AAA technique may provide better results with respect to agitation and seizure, but intraoperative hypertension needed a vigilant follow-up especially in the wake-up period. Copyright © 2016 Elsevier Ltd. All rights reserved.

Statins: the holy grail of Abdominal Aortic Aneurysm (AAA) growth attenuation? A systematic review of the literature.

PubMed

Dunne, Jonathan A; Bailey, Marc A; Griffin, Kathryn J; Sohrabi, Soroush; Coughlin, Patrick A; Scott, D Julian A

2014-01-01

In the era of Abdominal Aortic Aneurysm (AAA) screening, pharmacotherapies to attenuate AAA growth are sought. HMG Co-A reductase inhibitors (statins) have pleiotropic actions independent of their lipid lowering effects and have been suggested as potential treatment for small AAAs. We systematically review the clinical evidence for this effect. Medline, EMBASE and the Cochrane Central Register of Controlled Trials (1950-2011) were searched for studies reporting data on the role of statin therapy on AAA growth rate. No language restrictions were placed on the search. References of retrieved articles and pertinent journals were hand searched. Included studies were reviewed by 2 independent observers. The search retrieved 164 papers, 100 were irrelevant based on their title, 47 were reviews and 1 was a letter. 8 studies were excluded based on review of their abstract leaving 8 for inclusion in the study. Eight observational clinical studies with a total of 4,466 patients were reviewed. Four studies demonstrated reduced AAA expansion in statin users while 4 studies failed to demonstrate this effect. The method of determining AAA growth rates varied significantly between the studies and the ability of many studies to control for misclassification bias was poor. The claim that statins attenuate AAA growth remains questionable. Further prospective studies with stringent identification and verification of statin usage and a standardised method of estimating AAA growth rates are required. Statin type and dose also merit consideration.

Association between osteopontin and human abdominal aortic aneurysm.

PubMed

Golledge, Jonathan; Muller, Juanita; Shephard, Neil; Clancy, Paula; Smallwood, Linda; Moran, Corey; Dear, Anthony E; Palmer, Lyle J; Norman, Paul E

2007-03-01

In vitro and animal studies have implicated osteopontin (OPN) in the pathogenesis of aortic aneurysm. The relationship between serum concentration of OPN and variants of the OPN gene with human abdominal aortic aneurysm (AAA) was investigated. OPN genotypes were examined in 4227 subjects in which aortic diameter and clinical risk factors were measured. Serum OPN was measured by ELISA in two cohorts of 665 subjects. The concentration of serum OPN was independently associated with the presence of AAA. Odds ratios (and 95% confidence intervals) for upper compared with lower OPN tertiles in predicting presence of AAA were 2.23 (1.29 to 3.85, P=0.004) for the population cohort and 4.08 (1.67 to 10.00, P=0.002) for the referral cohort after adjusting for other risk factors. In 198 patients with complete follow-up of aortic diameter at 3 years, initial serum OPN predicted AAA growth after adjustment for other risk factors (standardized coefficient 0.24, P=0.001). The concentration of OPN in the aortic wall was greater in patients with small AAAs (30 to 50 mm) than those with aortic occlusive disease alone. There was no association between five single nucleotide polymorphisms or haplotypes of the OPN gene and aortic diameter or AAA expansion. Serum and tissue concentrations of OPN are associated with human AAA. We found no relationship between variation of the OPN gene and AAA. OPN may be a useful biomarker for AAA presence and growth.

Epidemiology and contemporary management of abdominal aortic aneurysms.

PubMed

Ullery, Brant W; Hallett, Richard L; Fleischmann, Dominik

2018-05-01

Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.

Protein quality control in organelles - AAA/FtsH story.

PubMed

Janska, Hanna; Kwasniak, Malgorzata; Szczepanowska, Joanna

2013-02-01

This review focuses on organellar AAA/FtsH proteases, whose proteolytic and chaperone-like activity is a crucial component of the protein quality control systems of mitochondrial and chloroplast membranes. We compare the AAA/FtsH proteases from yeast, mammals and plants. The nature of the complexes formed by AAA/FtsH proteases and the current view on their involvement in degradation of non-native organellar proteins or assembly of membrane complexes are discussed. Additional functions of AAA proteases not directly connected with protein quality control found in yeast and mammals but not yet in plants are also described shortly. Following an overview of the molecular functions of the AAA/FtsH proteases we discuss physiological consequences of their inactivation in yeast, mammals and plants. The molecular basis of phenotypes associated with inactivation of the AAA/FtsH proteases is not fully understood yet, with the notable exception of those observed in m-AAA protease-deficient yeast cells, which are caused by impaired maturation of mitochondrial ribosomal protein. Finally, examples of cytosolic events affecting protein quality control in mitochondria and chloroplasts are given. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids. Copyright © 2012 Elsevier B.V. All rights reserved.

Abdominal aortic aneurysm: novel mechanisms and therapies.

PubMed

Davis, Frank M; Rateri, Debra L; Daugherty, Alan

2015-11-01

Abdominal aortic aneurysm (AAA) is a pathological condition of permanent dilation that portends the potentially fatal consequence of aortic rupture. This review emphasizes recent advances in mechanistic insight into aneurysm pathogenesis and potential pharmacologic therapies that are on the horizon for AAAs. An increasing body of evidence demonstrates that genetic factors, including 3p12.3, DAB2IP, LDLr, LRP1, matrix metalloproteinase (MMP)-3, TGFBR2, and SORT1 loci, are associated with AAA development. Current human studies and animal models have shown that many leukocytes and inflammatory mediators, such as IL-1, IL-17, TGF-β, and angiotensin II, are involved in the pathogenesis of AAAs. Leukocytic infiltration into aortic media leads to smooth muscle cell depletion, generation of reactive oxygen species, and extracellular matrix fragmentation. Preclinical investigations into pharmacological therapies for AAAs have provided intriguing insight into the roles of microRNAs in regulating many pathological pathways in AAA development. Several large clinical trials are ongoing, seeking to translate preclinical findings into therapeutic options. Recent studies have identified many potential mechanisms involved in AAA pathogenesis that provide insight into the development of a medical treatment for this disease.

The m-AAA Protease Associated with Neurodegeneration Limits MCU Activity in Mitochondria.

PubMed

König, Tim; Tröder, Simon E; Bakka, Kavya; Korwitz, Anne; Richter-Dennerlein, Ricarda; Lampe, Philipp A; Patron, Maria; Mühlmeister, Mareike; Guerrero-Castillo, Sergio; Brandt, Ulrich; Decker, Thorsten; Lauria, Ines; Paggio, Angela; Rizzuto, Rosario; Rugarli, Elena I; De Stefani, Diego; Langer, Thomas

2016-10-06

Mutations in subunits of mitochondrial m-AAA proteases in the inner membrane cause neurodegeneration in spinocerebellar ataxia (SCA28) and hereditary spastic paraplegia (HSP7). m-AAA proteases preserve mitochondrial proteostasis, mitochondrial morphology, and efficient OXPHOS activity, but the cause for neuronal loss in disease is unknown. We have determined the neuronal interactome of m-AAA proteases in mice and identified a complex with C2ORF47 (termed MAIP1), which counteracts cell death by regulating the assembly of the mitochondrial Ca 2+ uniporter MCU. While MAIP1 assists biogenesis of the MCU subunit EMRE, the m-AAA protease degrades non-assembled EMRE and ensures efficient assembly of gatekeeper subunits with MCU. Loss of the m-AAA protease results in accumulation of constitutively active MCU-EMRE channels lacking gatekeeper subunits in neuronal mitochondria and facilitates mitochondrial Ca 2+ overload, mitochondrial permeability transition pore opening, and neuronal death. Together, our results explain neuronal loss in m-AAA protease deficiency by deregulated mitochondrial Ca 2+ homeostasis. Copyright © 2016 Elsevier Inc. All rights reserved.

Benefits and harms of screening men for abdominal aortic aneurysm in Sweden: a registry-based cohort study.

PubMed

Johansson, Minna; Zahl, Per Henrik; Siersma, Volkert; Jørgensen, Karsten Juhl; Marklund, Bertil; Brodersen, John

2018-06-16

Large reductions in the incidence of abdominal aortic aneurysm (AAA) and AAA-related mortality mean that results from randomised trials of screening for the disorder might be out-dated. The aim of this study was to estimate the effect of AAA screening in Sweden on disease-specific mortality, incidence, and surgery. Individual data on the incidence of AAA, AAA mortality, and surgery for AAA in a cohort of men aged 65 years who were invited to screening between 2006 and 2009, were compared with data from an age-matched contemporaneous cohort of men who were not invited for AAA screening. We also analysed national data for all men aged 40-99 years between Jan 1, 1987, and Dec 31, 2015, to explore background trends. Adjustment for confounding was done by weighting the analyses with a propensity score obtained from a logistic regression model on cohort year, marital status, educational level, income, and whether the patient already had an AAA diagnosis at baseline. Adjustment for differential attrition was also done by weighting the analyses with the inverse probability of still being in the cohort 6 years after screening. Generalised estimating equations were used to adjust the variance for repeated measurement and in response to the weighting. AAA mortality in Swedish men has decreased from 36 to ten deaths per 100 000 men aged 65-74 years between the early 2000s and 2015. Mortality decreased at similar rates in all Swedish counties, irrespective of whether AAA screening was offered. After 6 years with screening, we found a non-significant reduction in AAA mortality associated with screening (adjusted odds ratio [aOR] 0·76, 95% CI 0·38-1·51), which means that two men (95% CI -3 to 7) avoid death from AAA for every 10 000 men offered screening. Screening was associated with increased odds of AAA diagnosis (aOR 1·52, 95% CI 1·16-1·99; p=0·002) and an increased risk of elective surgery (aOR 1·59, 95% CI 1·20-2·10; p=0·001), such that for every 10 000 men offered screening, 49 men (95% CI 25-73) were likely to be overdiagnosed, 19 of whom (95% CI 1-37) had avoidable surgery that increased their risk of mortality and morbidity. AAA screening in Sweden did not contribute substantially to the large observed reductions in AAA mortality. The reductions were mostly caused by other factors, probably reduced smoking. The small benefit and substantially less favourable benefit-to-harm balance call the continued justification of the intervention into question. Research Unit and Section for General Practice, FoUU-centrum Fyrbodal, Sweden, and the region of Västra Götaland, Sweden. Copyright © 2018 Elsevier Ltd. All rights reserved.

Studies on the role of six enzymes in the metabolism of kinetin in mustard aphid, Lipaphis erysimi (Kalt.).

PubMed

Rup, Pushpinder J; Sohal, S K; Kaur, H

2006-07-01

The activity of catalase, glutathione peroxidase, superoxide dismutase, O-demethylase, ATPase and succinate dehydrogenase, belonging to two main classes of detoxification enzymes (i.e. hydrolases and oxido-reductases), mostly involved in metabolism and degradation of xenobiotics in insects, were assessed under the influence of kinetin, a plant growth regulator (PGR). The nymphs (48-52 hr old) of Lipaphis erysimi (Kalt.) were permitted to feed on radish plant, Raphanus sativus L. treated with kinetin (400 ppm) for 13, 25 and 37 hr. It was found that the activity of catalase, glutathione peroxidase and superoxide dismutase increased significantly when compared with the control of the same age group, which indicated that these enzymes might be playing a significant role in the metabolism of kinetin in this insect. The activity of O-demethylase showed an increase up to 25 hr of the treatment but it decreased under prolonged treatment whereas the activity of succinate dehydrogenase fluctuated insignificantly. ATPase showed a decrease in the activity with the treatment suggesting kinetin's interference in synthesis of ATPase.

Protective Effect of Eburicoic Acid of the Chicken of the Woods Mushroom, Laetiporus sulphureus (Higher Basidiomycetes), Against Gastric Ulcers in Mice.

PubMed

Wang, Junzhi; Sun, Wenjun; Luo, Huajun; He, Haibo; Deng, Weiqiao; Zou, Kun; Liu, Can; Song, Jing; Huang, Wenfeng

2015-01-01

In this study, we investigated the anti-inflammatory and tumor-inhibiting effects of eburicoic acid, the main bioactive component in the Laetiporus sulphureus, on gastric ulcers. A total of 48 Kunming mice were randomly divided into six groups: control, model, OL (omeprazole, 20 mg/kg/day, orally), EA-L (eburicoic acid, 10 mg/kg/day, orally), EA-M (eburicoic acid, 20 mg/kg/day, orally), and EA-H (eburicoic acid, 40 mg/kg/day, orally). Gastric ulcers were induced in mice by administering 80% ethanol containing 15 mg/mL aspirin (10.0 mL/kg, i.g.) 4 hours after drug administration on day 5. The ulcer index and H+/K+-ATPase activity were evaluated in vivo. Computer-aided molecular docking simulated the interaction between eburicoic acid and H+/K+-ATPase. The results showed that the oral administration of eburicoic acid protected the gastric mucosa from gastric lesions morphologically and especially attenuated H+/K+-ATPase activity. The results of this study indicate that the gastric protective effect of eburicoic acid might inhibit gastric acid.

Low prevalence of abdominal aortic aneurysm in the Seychelles population aged 50 to 65 years.

PubMed

Yerly, Patrick; Madeleine, George; Riesen, Walter; Bovet, Pascal

2013-03-01

The prevalence of abdominal aortic aneurysm (AAA) and its risk factors are well known in Western countries but few data are available from low- and middle- income countries. We are not aware of systematically collected population- based data on AAA in the African region. We evaluated the prevalence of AAA in a population- based cardiovascular survey conducted in the Republic of Seychelles in 2004 (Indian Ocean, African region). Among the 353 participants aged 50 to 64 years and screened with ultrasound, the prevalence of AAA was 0.3% (95% CI: 0- 0.9) and the prevalence of ectatic dilatations of the abdominal aorta was 1.5% (95% CI: 0.2- 2.8). The prevalence of AAA in the general population seemed lower in Seychelles than in Western countries, despite a high prevalence in Seychelles of risk factors of AAA, such as smoking (in men), high blood pressure and hypercholesterolaemia.

Recent Advances in Molecular Mechanisms of Abdominal Aortic Aneurysm Formation

PubMed Central

Annambhotla, Suman; Bourgeois, Sebastian; Wang, Xinwen; Lin, Peter H.; Yao, Qizhi; Chen, Changyi

2010-01-01

Abdominal Aortic Aneurysm (AAA) is an increasingly common clinical condition with fatal implications. It is associated with advanced age, male gender, cigarette smoking, atherosclerosis, hypertension, and genetic predisposition. Although significant evidence has emerged in the last decade, the molecular mechanisms of AAA formation remains poorly understood. Currently, the treatment for AAA remains primarily surgical with the lone innovation of endovascular therapy. With advance in the human genome, understanding precisely which molecules and genes mediate AAA development and blocking their activity at the molecular level could lead to important new discoveries and therapies. This review summarizes recent updates in molecular mechanisms of AAA formation including animal models, autoimmune components, infection, key molecules and cytokines, mechanical forces, genetics and pharmacotherapy. This review will be helpful to those who want to recognize the newest endeavors within the field and identify possible lines of investigation in AAA. PMID:18259804

In vivo topical application of acetyl aspartic acid increases fibrillin-1 and collagen IV deposition leading to a significant improvement of skin firmness.

PubMed

Gillbro, J M; Merinville, E; Cattley, K; Al-Bader, T; Hagforsen, E; Nilsson, M; Mavon, A

2015-10-01

Acetyl aspartic acid (A-A-A) was discovered through gene array analysis with corresponding Cmap analysis. We found that A-A-A increased keratinocyte regeneration, inhibited dermal matrix metalloprotease (MMP) expression and relieved fibroblast stiffness through reduction of the fibroblast stiffness marker F-actin. Dermal absorption studies showed successful delivery to both the epidermal and dermal regions, and in-use trial demonstrated that 1% A-A-A was well tolerated. In this study, the aim was to investigate whether A-A-A could stimulate the synthesis of extracellular matrix supporting proteins in vivo and thereby improving the viscoelastic properties of human skin by conducting a dual histological and biophysical clinical study. Two separate double-blind vehicle-controlled in vivo studies were conducted using a 1% A-A-A containing oil-in-water (o/w) emulsion. In the histological study, 16 female volunteers (>55 years of age) exhibiting photodamaged skin on their forearm were included, investigating the effect of a 12-day treatment of A-A-A on collagen IV (COLIV) and fibrillin-1. In a subsequent pilot study, 0.1% retinol was used for comparison to A-A-A (1%). The biomechanical properties of the skin were assessed in a panel of 16 women (>45 years of age) using the standard Cutometer MPA580 after topical application of the test products for 28 days. The use of multiple suction enabled the assessment of F4, an area parameter specifically representing skin firmness. Twelve-day topical application of 1% A-A-A significantly increased COLIV and fibrillin with 13% and 6%, respectively, compared to vehicle. 1% A-A-A and 0.1% retinol were found to significantly reduce F4 after 28 days of treatment by 15.8% and 14.7%, respectively, in the pilot Cutometer study. No significant difference was found between retinol and A-A-A. However, only A-A-A exhibited a significant effect vs. vehicle on skin firmness which indicated the incremental benefit of A-A-A as a skin-firming active ingredient. In this study, we showed the in vivo efficacy of 1% A-A-A both on a protein level (fibrillin and collagen IV) and on a clinical end point, specifically skin firmness, providing proof that, acetyl aspartic acid has a strong potential as an anti-ageing 'cosmeceutical' ingredient answering the needs of our key consumer base. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Antagonistic actions of renal dopamine and 5-hydroxytryptamine: increase in Na+, K(+)-ATPase activity in renal proximal tubules via activation of 5-HT1A receptors.

PubMed Central

Soares-da-Silva, P.; Pinto-do-O, P. C.; Bertorello, A. M.

1996-01-01

1. 5-Hydroxytryptamine (5-HT) is antinatriuretic. Since this effect of 5-HT is not accomplished by changes in glomerular haemodynamics, we have examined in this study whether 5-HT may influence sodium excretion by affecting the Na+, K(+)-ATPase activity in renal cortical tubules. 2. Na+, K(+)-ATPase activity was determined as the rate of [32P]-ATP hydrolysis in renal cortical tubules in suspension. Basal Na+, K(+)-ATPase activity in renal tubules was 4.8 +/- 0.4 mumol Pi mg-1 protein h-1 (n = 8). The 5-HT1A receptor agonist, (+/-)-8-hydroxy-2-(di-n-propylamino) tetraline (8-OH-DPAT) (10 to 3000 nM) induced a concentration-dependent increase (P < 0.05) in Na+, K(+)-ATPase activity with an EC50 value of 355 nM (95% confidence limits: 178, 708). Maximal stimulation elicited by 3000 nM of 8-OH-DPAT was antagonized by the selective 5-HT1A receptor antagonist, (+)-WAY 100135 10 to 1000 nM) with an IC50 value of 20 nM (14, 29); 0.3 microM (+)-WAY 100135 completely abolished (P < 0.01) the stimulatory effect of 8-OH-DPAT. The stimulatory effect of 8-OH-DPAT was found to be time-dependent (15 +/- 2% and 66 +/- 7% increase at 2.5 and 5.0 min, respectively). The 5-HT2 receptor agonist alpha-methyl-5-HT (100 to 3000 nM) did not induce any significant changes in Na+, K(+)-ATPase activity (5.0 +/- 1.5 mumol Pi mg-1 protein h-1; n = 4). 3. The stimulatory effect 8-OH-DPAT was absent when homogenates were used. Stimulation occurred at a Vmax concentration (70 mM) of sodium supporting the notion that stimulation occurs independently of increasing sodium permeability. 4. The inhibitory effect of dopamine (P < 0.05) on Na+, K(+)-ATPase activity was blunted by co-incubation with 8-OH-DPAT (0.5 microM). 5. It is concluded that activation of 5-HT1A receptors increases Na+, K(+)-ATPase activity in renal cortical tubules; this effect may represent an important cellular mechanism, at the tubule level, responsible for the antinatriuretic effect of 5-HT. Images Figure 4 PMID:8882616

Ruptured Abdominal Aortic Aneurysm: Prediction of Mortality From Clinical Presentation and Glasgow Aneurysm Score.

PubMed

Weingarten, Toby N; Thompson, Lauren T; Licatino, Lauren K; Bailey, Christopher H; Schroeder, Darrell R; Sprung, Juraj

2016-04-01

To examine association of presenting clinical acuity and Glasgow Aneurysm Score (GAS) with perioperative and 1-year mortality. Retrospective chart review. Major tertiary care facility. Patients with ruptured abdominal aortic aneurysm (rAAA) from 2003 through 2013. Emergency repair of rAAA. The authors reviewed outcomes after stable versus unstable presentation and by GAS. Unstable presentation included hypotension, cardiac arrest, loss of consciousness, and preoperative tracheal intubation. In total, 125 patients (40 stable) underwent repair. Perioperative mortality rates were 41% and 12% in unstable and stable patients, respectively (p<0.001). Unstable status had 88% sensitivity and 41% specificity for predicting perioperative mortality. Using logistic regression, higher GAS was associated with perioperative mortality (p<0.001). Using receiver operating characteristic analysis, the area under the curve was 0.72 (95% CI, 0.62-0.82) and cutoff GAS≥96 had 63% and 72% sensitivity and specificity, respectively. Perioperative mortality for GAS≥96 was 51% (25/49), whereas it was 20% (15/76) for GAS≤95. The estimated 1-year survival (95% CI) was 75% (62%-91%) for stable patients and 48% (38%-60%) for unstable patients. Estimated 1-year survival (95% CI) was 23% (13%-40%) for GAS≥96 and 77% (67%-87%) for GAS≤95. Clinical presentation and GAS identified patients with rAAA who were likely to have a poor surgical outcome. GAS≥96 was associated with poor long-term survival, but>20% of these patients survived 1 year. Thus, neither clinical presentation nor GAS provided reliable guidance for decisions regarding futility of surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

The Relationship Between Serum Interleukin-1α and Asymptomatic Infrarenal Abdominal Aortic Aneurysm Size, Morphology, and Growth Rates.

PubMed

Ahmad, Mehtab; Kuravi, Sahithi; Hodson, James; Rainger, G Ed; Nash, Gerard B; Vohra, Rajiv K; Bradbury, Andrew W

2018-02-16

In a pilot study, a relationship between abdominal aortic aneurysm (AAA) diameter and serum interleukin (IL)-1α levels was reported, and that endothelial cell (EC) activation in vitro in response to serum from patients with AAA was blocked by anti-IL-1α antibodies. The aim of the present study was to further investigate the relationship between serum IL-1α and asymptomatic infrarenal AAA size, morphology, and growth rates. Serum IL-1α was measured using enzyme linked immunosorbent assay in 101 patients with asymptomatic, infrarenal AAA and related to aneurysm size, morphology, and growth rates. IL-1α was measured in 101 patients. There was no statistically significant difference in mean age between men and women. IL-1α was detectable in 62.4% of patients; median IL-1α titre was 3.26 pg/mL. There was no statistically significant relationship between IL-1α and maximum AAA antero-posterior diameter as measured by ultrasound (p = .649), AAA morphology (aortic length [p = .394], sac [p = .369], and thrombus volume [p = .629]) as measured on computed tomography, absolute increase in AAA diameter (p = .214), or AAA growth rate (p = .230). IL-1α is detectable in the majority of patients with infrarenal AAA, but the cause and clinical significance of this novel observation remains unknown. Copyright © 2018 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Endothelial and smooth muscle cells from abdominal aortic aneurysm have increased oxidative stress and telomere attrition.

PubMed

Cafueri, Giuseppe; Parodi, Federica; Pistorio, Angela; Bertolotto, Maria; Ventura, Francesco; Gambini, Claudio; Bianco, Paolo; Dallegri, Franco; Pistoia, Vito; Pezzolo, Annalisa; Palombo, Domenico

2012-01-01

Abdominal aortic aneurysm (AAA) is a complex multi-factorial disease with life-threatening complications. AAA is typically asymptomatic and its rupture is associated with high mortality rate. Both environmental and genetic risk factors are involved in AAA pathogenesis. Aim of this study was to investigate telomere length (TL) and oxidative DNA damage in paired blood lymphocytes, aortic endothelial cells (EC), vascular smooth muscle cells (VSMC), and epidermal cells from patients with AAA in comparison with matched controls. TL was assessed using a modification of quantitative (Q)-FISH in combination with immunofluorescence for CD31 or α-smooth muscle actin to detect EC and VSMC, respectively. Oxidative DNA damage was investigated by immunofluorescence staining for 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG). Telomeres were found to be significantly shortened in EC, VSMC, keratinocytes and blood lymphocytes from AAA patients compared to matched controls. 8-oxo-dG immunoreactivity, indicative of oxidative DNA damage, was detected at higher levels in all of the above cell types from AAA patients compared to matched controls. Increased DNA double strand breaks were detected in AAA patients vs controls by nuclear staining for γ-H2AX histone. There was statistically significant inverse correlation between TL and accumulation of oxidative DNA damage in blood lymphocytes from AAA patients. This study shows for the first time that EC and VSMC from AAA have shortened telomeres and oxidative DNA damage. Similar findings were obtained with circulating lymphocytes and keratinocytes, indicating the systemic nature of the disease. Potential translational implications of these findings are discussed.

Abdominal aortic aneurysm screening program using hand-held ultrasound in primary healthcare

PubMed Central

Kostov, Belchin; Navarro González, Marta; Cararach Salami, Daniel; Pérez Jiménez, Alfonso; Gilabert Solé, Rosa; Bru Saumell, Concepció; Donoso Bach, Lluís; Villalta Martí, Mireia; González-de Paz, Luis; Ruiz Riera, Rafael; Riambau Alonso, Vicenç; Acar-Denizli, Nihan; Farré Almacellas, Marta; Ramos-Casals, Manuel; Benavent Àreu, Jaume

2017-01-01

We determined the feasibility of abdominal aortic aneurysm (AAA) screening program led by family physicians in public primary healthcare setting using hand-held ultrasound device. The potential study population was 11,214 men aged ≥ 60 years attended by three urban, public primary healthcare centers. Participants were recruited by randomly-selected telephone calls. Ultrasound examinations were performed by four trained family physicians with a hand-held ultrasound device (Vscan®). AAA observed were verified by confirmatory imaging using standard ultrasound or computed tomography. Cardiovascular risk factors were determined. The prevalence of AAA was computed as the sum of previously-known aneurysms, aneurysms detected by the screening program and model-based estimated undiagnosed aneurysms. We screened 1,010 men, with mean age of 71.3 (SD 6.9) years; 995 (98.5%) men had normal aortas and 15 (1.5%) had AAA on Vscan®. Eleven out of 14 AAA-cases (78.6%) had AAA on confirmatory imaging (one patient died). The total prevalence of AAA was 2.49% (95%CI 2.20 to 2.78). The median aortic diameter at diagnosis was 3.5 cm in screened patients and 4.7 cm (p<0.001) in patients in whom AAA was diagnosed incidentally. Multivariate logistic regression analysis identified coronary heart disease (OR = 4.6, 95%CI 1.3 to 15.9) as the independent factor with the highest odds ratio. A screening program led by trained family physicians using hand-held ultrasound was a feasible, safe and reliable tool for the early detection of AAA. PMID:28453577

Salinity acclimation enhances salinity tolerance in tadpoles living in brackish water through increased Na⁺ , K⁺ -ATPase expression.

PubMed

Wu, Chi-Shiun; Yang, Wen-Kai; Lee, Tsung-Han; Gomez-Mestre, Ivan; Kam, Yeong-Choy

2014-01-01

Amphibians are highly susceptible to osmotic stress but, nonetheless, some species can adapt locally to withstand moderately high levels of salinity. Maintaining the homeostasis of body fluids by efficient osmoregulation is thus critical for larval survival in saline environments. We studied the role of acclimation in increased physiological tolerance to elevated water salinity in the Indian rice frog (Fejervarya limnocharis) tadpoles exposed to brackish water. We quantified the effects of salinity acclimation on tadpole survival, osmolality, water content, and gill Na⁺ , K⁺ -ATPase (NKA) expression. Tadpoles did not survive over 12 hr if directly transferred to 11 ppt (parts per thousand) whereas tadpoles previously acclimated for 48 hr in 7  ppt survived at least 48 hr. We reared tadpoles in 3 ppt and then we transferred them to one of (a) 3 ppt, (b) 11  ppt, and (c) 7  ppt for 48 hr and then 11 ppt. In the first 6 hr after transfer to 11 ppt, tadpole osmolality sharply increased and tadpole water content decreased. Tadpoles pre-acclimated for 48 hr in 7 ppt were able to maintain lower and more stable osmolality within the first 3 hr after transfer. These tadpoles initially lost water content, but over the next 6 hr gradually regained water and stabilized. In addition, they had a higher relative abundance of NKA proteins than tadpoles in other treatments. Pre-acclimation to 7 ppt for 48 hr was hence sufficient to activate NKA expression, resulting in increased survivorship and reduced dehydration upon later transfer to 11 ppt. J © 2013 Wiley Periodicals, Inc.

Disparities in outcomes for Hispanic patients undergoing endovascular and open abdominal aortic aneurysm repair.

PubMed

Williams, Timothy K; Schneider, Eric B; Black, James H; Lum, Ying Wei; Freischlag, Julie A; Perler, Bruce A; Abularrage, Christopher J

2013-01-01

Previous studies have demonstrated racial and ethnic disparities associated with the outcomes of abdominal aortic aneurysm (AAA) repair, although little is known about the influence of race and ethnicity on the costs associated with these disparities. The current study was undertaken to examine the influence of race and ethnicity on the outcomes of endovascular (EVAR) and open repair (open AAA) of unruptured AAA and its effect on costs in contemporary practice. The Nationwide Inpatient Sample (2005 to 2008) was queried using ICD-9-CM codes for unruptured AAA (441.4). The primary outcomes were mortality and total hospital charges. Multivariate analyses were performed adjusting for age, gender, race, comorbidities (Charlson index), year, insurance type, and hospital characteristics. A total of 62,728 patients underwent EVAR and 24,253 patients underwent open AAA. White patients (72%) were more likely to undergo EVAR than Hispanic (69%) or black patients (69%; P = 0.02). On univariate analysis, in-hospital mortality after EVAR was increased in Hispanic patients compared with white patients (1% vs 2%; P = 0.02). There were no differences in mortality after EVAR between white and black patients, and there were no racial or ethnic differences in mortality after open AAA. Hispanic ethnicity remained an independent risk factor for increased mortality after AAA repair on multivariate analysis (RR 1.64; 95% CI [1.05 to 2.57]; P = 0.03). Hispanic ethnicity was associated with increased hospital charges compared with white ethnicity after both EVAR ($108,886 vs $77,748; P < 0.001) and open AAA ($134,356 vs $85,536; P < 0.001) and for black patients after open AAA ($101,168 vs $85,536; P = 0.04). Hispanic ethnicity is an independent risk factor for mortality after AAA repair independent of insurance type or hospital characteristics. There were dramatic disparities in hospital costs for Hispanic patients undergoing either EVAR or open AAA and for black patients after open AAA compared with white patients. This observation seems unrelated to length of stay, postoperative complications, and admission status. Further studies are needed to determine whether these disparities extend beyond the primary hospitalization. Copyright © 2013 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

Safety assessment of a novel active ingredient, acetyl aspartic acid, according to the EU Cosmetics Regulation and the Scientific Committee on Consumer Safety guidelines.

PubMed

Daly, P; Moran, G

2015-10-01

Acetyl aspartic acid (A-A-A) was proposed as a new novel active ingredient for use in cosmetics. The safety of A-A-A was assessed by following an in-house-developed 'New Ingredient Testing Strategy', which was designed in accordance with the Scientific Committee on Consumer Safety (SCCS) notes of guidance and the requirements of Annex I of the EU Cosmetics Regulation. The aim of the project was to determine whether A-A-A was safe for use in cosmetics and to determine a maximum permitted safe level in the formulations. A literature review was conducted, consulting over 40 different information sources. This highlighted a number of gaps which required testing data. A-A-A was tested for phototoxicity according to OECD test guideline 432, skin irritation according to OECD test guideline 439 and eye irritation according to OECD test guideline 437. Dermal absorption of A-A-A was measured according to OECD test guideline 428 and was used to calculate the margin of safety (MoS). Finally, A-A-A was tested in a human repeat insult patch test (HRIPT) and a 14-day in-use tolerance study. A-A-A was non-phototoxic and was non-irritating to skin and eyes in in vitro testing. Dermal absorption was calculated to be 5%. The MoS for A-A-A was 351, at a level of 5%, for all cosmetic product types, indicating no systemic safety toxicity concern. A-A-A at 5% under occlusive patch on a panel of 50 adult volunteers induced no skin irritation or allergic reaction in the HRIPT study. Finally, repeated application of A-A-A to the periocular area, twice per day for 14 days, in 21 female volunteers, demonstrated that 1% A-A-A was well tolerated following dermatological and ophthalmological assessment in a cosmetic formulation. A-A-A was assessed as safe by the cosmetic safety assessor for use in cosmetics at a level of 5% in all cosmetic product types, in line with the requirements of the EU Cosmetics Regulation and in accordance with the SCCS notes of guidance. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Inflammatory Cells and Proteases in Abdominal Aortic Aneurysm and its Complications.

PubMed

Haiying, Jiang; Sasaki, Takeshi; Jin, Enze; Kuzuya, Masafumi; Cheng, Xianwu

2018-05-30

Abdominal aortic aneurysm (AAA), a common disease among elderly individuals, involves the progressive dilatation of the abdominal aorta as a consequence of degeneration. The mechanisms of AAA formation, development and rupture are largely unknown. Surgical repair is the only available method of treatment since the lack of knowledge regarding the pathogenesis of AAA has hindered the development of suitable medical treatments, particularly the development of drugs. In this review, we describe the inflammatory cells and proteases that may be involved in the formation and development of AAA. This knowledge can contribute to the development of new drugs for AAA. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Associations of Diabetes and Obesity with Risk of Abdominal Aortic Aneurysm in Men.

PubMed

Wang, Lu; Djousse, Luc; Song, Yiqing; Akinkuolie, Akintunde O; Matsumoto, Chisa; Manson, JoAnn E; Gaziano, J Michael; Sesso, Howard D

2017-01-01

Background. The associations of diabetes and obesity with the risk of abdominal aortic aneurysm (AAA) are inconclusive in previous studies. Subjects/Methods. We conducted prospective analysis in the Physicians' Health Study. Among 25,554 male physicians aged ≥ 50 years who reported no AAA at baseline, 471 reported a newly diagnosed AAA during a mean of 10.4 years' follow-up. Results. Compared with men who had baseline body mass index (BMI) < 25 kg/m 2 , the multivariable hazard ratio (HR [95% CI]) of newly diagnosed AAA was 1.30 [1.06-1.59] for BMI 25-<30 kg/m 2 and 1.69 [1.24-2.30] for BMI ≥ 30 kg/m 2 . The risk of diagnosed AAA was significantly higher by 6% with each unit increase in baseline BMI. This association was consistent regardless of the other known AAA risk factors and preexisting vascular diseases. Overall, baseline history of diabetes tended to be associated with a lower risk of diagnosed AAA (HR = 0.79 [0.57-1.11]); this association appeared to vary by follow-up time (HR = 1.56 and 0.63 during ≤ and >2 years' follow-up, resp.). Conclusion. In a large cohort of middle-aged and older men, obesity was associated with a higher risk, while history of diabetes tended to associate with a lower risk of diagnosed AAA, particularly over longer follow-up.

Impact of isotropic constitutive descriptions on the predicted peak wall stress in abdominal aortic aneurysms.

PubMed

Man, V; Polzer, S; Gasser, T C; Novotny, T; Bursa, J

2018-03-01

Biomechanics-based assessment of Abdominal Aortic Aneurysm (AAA) rupture risk has gained considerable scientific and clinical momentum. However, computation of peak wall stress (PWS) using state-of-the-art finite element models is time demanding. This study investigates which features of the constitutive description of AAA wall are decisive for achieving acceptable stress predictions in it. Influence of five different isotropic constitutive descriptions of AAA wall is tested; models reflect realistic non-linear, artificially stiff non-linear, or artificially stiff pseudo-linear constitutive descriptions of AAA wall. Influence of the AAA wall model is tested on idealized (n=4) and patient-specific (n=16) AAA geometries. Wall stress computations consider a (hypothetical) load-free configuration and include residual stresses homogenizing the stresses across the wall. Wall stress differences amongst the different descriptions were statistically analyzed. When the qualitatively similar non-linear response of the AAA wall with low initial stiffness and subsequent strain stiffening was taken into consideration, wall stress (and PWS) predictions did not change significantly. Keeping this non-linear feature when using an artificially stiff wall can save up to 30% of the computational time, without significant change in PWS. In contrast, a stiff pseudo-linear elastic model may underestimate the PWS and is not reliable for AAA wall stress computations. Copyright © 2018 IPEM. Published by Elsevier Ltd. All rights reserved.

Effect of AMPK signal pathway on pathogenesis of abdominal aortic aneurysms

PubMed Central

Yang, Le; Shen, Lin; Gao, Peixian; Li, Gang; He, Yuxiang; Wang, Maohua; Zhou, Hua; Yuan, Hai; Jin, Xing; Wu, Xuejun

2017-01-01

Background and aims Determine the effect of AMPK activation and inhibition on the development of AAA (abdominal aortic aneurysm). Methods AAA was induced in ApoE−/− mice by Ang II (Angiotensin II)-infusion. AICAR (5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside) was used as AMPK activator and Compound C was used as AMPK inhibitor. We further investigate the effect of metformin, a widely used anti-diabetic drug which could activate AMPK signal pathway, on the pathogenesis of aneurysm. Results Phospho-AMPK level was significantly decreased in AAA tissue compared with control aortas. AICAR significantly reduced the incidence, severity and mortality of aneurysm in the Ang II-infusion model. AICAR also alleviated macrophage infiltration and neovascularity in Ang II infusion model at day 28. The expression of pro-inflammatory factors, angiogenic factors and the activity of MMPs were also alleviated by AICAR during AAA induction. On the other hand, Compound C treatment did not exert obvious protective effect. AMPK activation may inhibit the activation of nuclear factor-κB (NF-κB) and signal transducer and activator of transcription-3 (STAT-3) during AAA induction. Administration of metformin also activated AMPK signal pathway and retarded AAA progression in Ang II infusion model. Conclusions Activation of AMPK signaling pathway may inhibit the Ang II-induced AAA in mice. Metformin may be a promising approach to the treatment of AAA. PMID:29190959

Assessment of the accuracy of AortaScan for detection of abdominal aortic aneurysm (AAA).

PubMed

Abbas, A; Smith, A; Cecelja, M; Waltham, M

2012-02-01

AortaScan AMI 9700 is a portable 3D ultrasound device that automatically measures the maximum diameter of the abdominal aorta without the need for a trained sonographer. It is designed to rapidly diagnose or exclude an AAA and may have particular use in screening programs. Our objective was to determine its accuracy to detect AAA. Subjects from our AAA screening and surveillance programs were examined. The aorta was scanned using the AortaScan and computed tomography (CT). Ninety-one subjects underwent imaging (44 AAA on conventional ultrasound surveillance and 47 controls). The largest measurement obtained by AortaScan was compared against the CT-aortic measurement. The mean aortic diameter was 2.8 cm. The CT scan confirmed the diagnosis of AAA in 43 subjects. There was one false positive measurement on conventional ultrasound. AortaScan missed the diagnosis of AAA in eight subjects. There were thirteen false positive measurements. The sensitivity, specificity, positive and negative predictive values were 81%, 72%, 72% and 81% respectively. A device to detect AAA without the need for a trained operator would have potential in a community-based screening programme. The AortaScan, however, lacks adequate sensitivity and significant technical improvement is necessary before it could be considered a replacement for trained screening personnel. Copyright © 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

On the potential increase of the oxidative stress status in patients with abdominal aortic aneurysm.

PubMed

Pincemail, J; Defraigne, J O; Cheramy-Bien, J P; Dardenne, N; Donneau, A F; Albert, A; Labropoulos, N; Sakalihasan, N

2012-01-01

Abdominal aortic aneurysm (AAA) is a major cause of preventable deaths in older patients. Oxidative stress has been suggested to play a key role in the pathogenesis of AAA. However, only few studies have been conducted to evaluate the blood oxidative stress status of AAA patients. Twenty seven AAA patients (mean age of 70 years) divided into two groups according to AAA size (≤ 50 or > 50 mm) were compared with an age-matched group of 18 healthy subjects. Antioxidants (vitamins C and E, β-carotene, glutathione, thiols, and ubiquinone), trace elements (selenium, copper, zinc, and copper/zinc ratio) and markers of oxidative damage to lipids (lipid peroxides, antibodies against oxidized patients, and isoprostanes) were measured in each subject. The comparison of the three groups by ordinal logistic regression showed a significant decrease of the plasma levels of vitamin C (P = 0.011), α-tocopherol (P = 0.016) but not when corrected for cholesterol values, β-carotene (P = 0.0096), ubiquinone (P = 0.014), zinc (P = 0.0035), and of selenium (P = 0.0038), as AAA size increased. By contrast, specific markers of lipid peroxidation such as the Cu/Zn ratio (P = 0.046) and to a lesser extent isoprostanes (P = 0.052) increased. The present study emphasizes the potential role of the oxidative stress in AAA disease and suggests that an antioxidant therapy could be of interest to delay AAA progression.

Abdominal Aortic Aneurysms in “High-Risk” Surgical Patients

PubMed Central

Jordan, William D.; Alcocer, Francisco; Wirthlin, Douglas J.; Westfall, Andrew O.; Whitley, David

2003-01-01

Objective To evaluate the early results of endovascular grafting for high-risk surgical candidates in the treatment of abdominal aortic aneurysms (AAA). Summary Background Data Since the approval of endoluminal grafts for treatment of AAA, endovascular repair of AAA (EVAR) has expanded to include patients originally considered too ill for open AAA repair. However, some concern has been expressed regarding technical failure and the durability of endovascular grafts. Methods The University of Alabama at Birmingham (UAB) Computerized Vascular Registry identified all patients who underwent abdominal aneurysm repair between January 1, 2000, and June 12, 2002. Patients were stratified by type of repair (open AAA vs. EVAR) and were classified as low risk or high risk. Patients with at least one of the following classifications were classified as high risk: age more than 80 years, chronic renal failure (creatinine > 2.0), compromised cardiac function (diminished ventricular function or severe coronary artery disease), poor pulmonary function, reoperative aortic procedure, a “hostile” abdomen, or an emergency operation. Death, systemic complications, and length of stay were tabulated for each group. Results During this 28-month period, 404 patients underwent AAA repair at UAB. Eighteen patients (4.5%) died within 30 days of their repair or during the same hospitalization. Two hundred seventeen patients (53%) were classified as high risk. Two hundred fifty-nine patients (64%) underwent EVAR repair, and 130 (50%) of these were considered high-risk patients (including four emergency procedures). One hundred forty-five patients (36%) underwent open AAA repair, including 15 emergency operations. All deaths occurred in the high-risk group: 12 (8.3%) died after open AAA repair and 6 (2.3%) died after EVAR repair. Postoperative length of stay was shorter for EVAR repair compared to open AAA. Conclusions High-risk and low-risk patients can undergo EVAR repair with a lower rate of short-term systemic complications and a shorter length of stay compared to open AAA. Despite concern regarding the durability of EVAR, high-risk patients should be evaluated for EVAR repair before committing to open AAA repair. PMID:12724628

SU-F-T-609: Impact of Dosimetric Variation for Prescription Dose Using Analytical Anisotropic Algorithm (AAA) in Lung SBRT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawai, D; Takahashi, R; Kamima, T

Purpose: Actual irradiated prescription dose to patients cannot be verified. Thus, independent dose verification and second treatment planning system are used as the secondary check. AAA dose calculation engine has contributed to lung SBRT. We conducted a multi-institutional study to assess variation of prescription dose for lung SBRT when using AAA in reference to using Acuros XB and Clarkson algorithm. Methods: Six institutes in Japan participated in this study. All SBRT treatments were planed using AAA in Eclipse and Adaptive Convolve (AC) in Pinnacle3. All of the institutes used a same independent dose verification software program (Simple MU Analysis: SMU,more » Triangle Product, Ishikawa, Japan), which implemented a Clarkson-based dose calculation algorithm using CT image dataset. A retrospective analysis for lung SBRT plans (73 patients) was performed to compute the confidence limit (CL, Average±2SD) in dose between the AAA and the SMU. In one of the institutes, a additional analysis was conducted to evaluate the variations between the AAA and the Acuros XB (AXB). Results: The CL for SMU shows larger systematic and random errors of 8.7±9.9 % for AAA than the errors of 5.7±4.2 % for AC. The variations of AAA correlated with the mean CT values in the voxels of PTV (a correlation coefficient : −0.7) . The comparison of AXB vs. AAA shows smaller systematic and random errors of −0.7±1.7%. The correlation between dose variations for AXB and the mean CT values in PTV was weak (0.4). However, there were several plans with more than 2% deviation of AAPM TG114 (Maximum: −3.3 %). Conclusion: In comparison for AC, prescription dose calculated by AAA may be more variable in lung SBRT patient. Even AXB comparison shows unexpected variation. Care should be taken for the use of AAA in lung SBRT. This research is partially supported by Japan Agency for Medical Research and Development (AMED)« less

A knowledge-based design framework for airplane conceptual and preliminary design

NASA Astrophysics Data System (ADS)

Anemaat, Wilhelmus A. J.

The goal of work described herein is to develop the second generation of Advanced Aircraft Analysis (AAA) into an object-oriented structure which can be used in different environments. One such environment is the third generation of AAA with its own user interface, the other environment with the same AAA methods (i.e. the knowledge) is the AAA-AML program. AAA-AML automates the initial airplane design process using current AAA methods in combination with AMRaven methodologies for dependency tracking and knowledge management, using the TechnoSoft Adaptive Modeling Language (AML). This will lead to the following benefits: (1) Reduced design time: computer aided design methods can reduce design and development time and replace tedious hand calculations. (2) Better product through improved design: more alternative designs can be evaluated in the same time span, which can lead to improved quality. (3) Reduced design cost: due to less training and less calculation errors substantial savings in design time and related cost can be obtained. (4) Improved Efficiency: the design engineer can avoid technically correct but irrelevant calculations on incomplete or out of sync information, particularly if the process enables robust geometry earlier. Although numerous advancements in knowledge based design have been developed for detailed design, currently no such integrated knowledge based conceptual and preliminary airplane design system exists. The third generation AAA methods are tested over a ten year period on many different airplane designs. Using AAA methods will demonstrate significant time savings. The AAA-AML system will be exercised and tested using 27 existing airplanes ranging from single engine propeller, business jets, airliners, UAV's to fighters. Data for the varied sizing methods will be compared with AAA results, to validate these methods. One new design, a Light Sport Aircraft (LSA), will be developed as an exercise to use the tool for designing a new airplane. Using these tools will show an improvement in efficiency over using separate programs due to the automatic recalculation with any change of input data. The direct visual feedback of 3D geometry in the AAA-AML, will lead to quicker resolving of problems as opposed to conventional methods.

Prospective Observational Evaluation of Time-Dependency of Adalimumab Immunogenicity and Drug Concentrations: The Poetic Study.

PubMed

Ungar, Bella; Engel, Tal; Yablecovitch, Doron; Lahat, Adi; Lang, Alon; Avidan, Benjamin; Har-Noy, Ofir; Carter, Dan; Levhar, Nina; Selinger, Limor; Neuman, Sandra; Natour, Ola Haj; Yavzori, Miri; Fudim, Ella; Picard, Orit; Kopylov, Uri; Chowers, Yehuda; Naftali, Timna; Broide, Efrat; Shachar, Eyal; Eliakim, Rami; Ben-Horin, Shomron

2018-06-01

Adalimumab is usually self-injected at home, making prospective serial-sampling studies challenging and scarce. This has led to a gap in knowledge about evolution of anti-adalimumab antibodies (AAAs) over time and its correlation with clinical and inflammatory outcomes. A program for home visits by physicians at induction, every 3 months and at event of relapse, was established prospectively for Crohn's disease (CD) patients. At each visit, patients' clinical scores were determined and sera were obtained for C-reactive protein, drug, and AAA levels. This cohort was compared to a parallel prospective cohort of infliximab-treated CD patients. In a subgroup of 29 patients, trough and in-between-trough levels were compared, to elucidate the importance of timing of sampling during the injection cycle. Ninety-eight CD patients starting adalimumab were prospectively followed (median follow-up 44 weeks) and 621 serum samples were analyzed. Thirty-three patients (32%) developed AAA; 18/33 (55%) of them as early as week 2, and 26/33 (79%) by week 14. Induction period AAAs were strongly associated with primary non-response (odds ratio (OR) = 5.4, 95% confidence interval (CI): 1.6-17.8, p = 0.005). As compared to antibodies-to-infliximab (ATI), AAA formation rate over time was significantly lower (p = 0.01) and AAA were much more specific-85% of AAA events were associated with loss-of-response compared with 58% rate for ATI (p = 0.01). In 29 patients sampled serially during an injection cycle, levels of drug and AAA seemed comparable between four time-points during a single cycle both in patients with or without AAA (n = 8, n = 21, respectively). When followed prospectively and serially, AAAs are found to arise earlier than previously appreciated and their impact may be more pronounced for primary rather than secondary, non-response. Drug and AAA levels were similar both at trough and in-between injections, enabling to simplify therapeutic drug monitoring of adalimumab.

Adalimumab for Treatment of Noninfectious Uveitis: Immunogenicity and Clinical Relevance of Measuring Serum Drug Levels and Antidrug Antibodies.

PubMed

Cordero-Coma, Miguel; Calleja-Antolín, Sara; Garzo-García, Irene; Nuñez-Garnés, Ana M; Álvarez-Castro, Carolina; Franco-Benito, Manuel; Ruiz de Morales, Jose G

2016-12-01

To evaluate the rate of immunogenicity induced by adalimumab and its relationship with drug serum levels and clinical responses in patients with noninfectious uveitis. Prospective observational study. Consecutive patients from 1 referral center who initiated treatment with adalimumab for active noninfectious uveitis resistant to conventional therapy. All patients received 40 mg adalimumab every other week. Patients were evaluated clinically and immunologically before and after 4, 8, and 24 weeks of treatment. Clinical evaluation included assessment of changes in visual acuity, degree of inflammation in the anterior chamber and vitreous cavity, central macular thickness, and retinal angiographic leakage. Immunologic evaluation included assessment of serum trough adalimumab and antibodies against adalimumab (AAA) levels and class II HLA typing. Twenty-five patients were enrolled. Overall, 18 of 25 patients (72%) showed a favorable clinical response to adalimumab therapy. Eleven patients (44%) achieved a complete response and 7 (28%) achieved a partial response. However, 7 of 25 patients (28%) were considered nonresponders. Median trough adalimumab serum levels were higher in responders than in nonresponders (P < 0.001). We observed AAA positivity (AAA+) at least 1 time point in 8 of 25 patients (32%), including 4 with transitory AAA and 4 with permanent AAA. In all patients with permanent AAA+, trough adalimumab levels became undetectable (P < 0.001). However, in patients who demonstrated transitory AAA+, no correlation was observed between AAA titers and adalimumab trough levels (P = 0.2).Concomitant immunosuppression did not show any protective effect on adalimumab immunogenicity in our cohort. An association between the presence of AAA+ and a worse uveitis outcome was observed only in patients with permanent AAA+, which correlated with undetectable adalimumab trough levels (P = 0.014). Treatment of noninfectious uveitis with adalimumab is associated with high rates of favorable clinical response. Overall, adalimumab trough levels were higher in responder patients. Development of permanent AAA was associated with undetectable trough adalimumab levels and worse uveitis outcome. Immunogenicity was more common in patients in whom uveitis was associated with a systemic disease and was not influenced by concomitant immunosuppressors. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Uranium series dating of human skeletal remains from the Del Mar and Sunnyvale sites, California

USGS Publications Warehouse

Bischoff, J.L.; Rosenbauer, R.J.

1981-01-01

Uranium series analyses of human bone samples from the Del Mar and Sunnyvale sites indicate ages of 11,000 and 8,300 years, respectively. The dates are supported by internal concordancy between thorium-230 and protactinium-231 decay systems. These ages are significantly younger than the estimates of 48,000 and 70,000 years based on amino acid racemization, and indicate that the individuals could derive from the population waves that came across the Bering Strait during the last sea-level low. Copyright ?? 1981 AAAS.

Abortion surveillance--United States, 1998.

PubMed

Herndon, Joy; Strauss, Lilo T; Whitehead, Sara; Parker, Wilda Y; Bartlett, Linda; Zane, Suzanne

2002-06-07

In 1969, CDC began abortion surveillance to document the number and characteristics of women obtaining legal induced abortions, to monitor unintended pregnancy, and to assist efforts to identify and reduce preventable causes of morbidity and mortality associated with abortions. This report summarizes and reviews information reported to CDC regarding legal induced abortions obtained in the United States in 1998. For each year since 1969, CDC has compiled abortion data by occurrence. From 1973 to 1997, data were received from or estimated for 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City. In 1998, CDC compiled abortion data from only 48 reporting areas; Alaska, California, New Hampshire, and Oklahoma did not report. In 1998, 884,273 legal induced abortions were reported to CDC, representing a 2% decrease from the 900,171 legal induced abortions reported by the same 48 reporting areas for 1997. The abortion ratio, defined as the number of abortions per 1,000 live births, was 264, compared with 274 in 1997 (for the same 48 areas); the abortion rate for these 48 areas was 17 per 1,000 women aged 15-44 years for both 1997 and 1998. The availability of information about characteristics of women who obtained an abortion in 1998 varied by state and by the number of states reporting each characteristic. The total number of legal induced abortions by state is reported by state of residence and state of occurrence; characteristics of women obtaining abortions in 1998 are reported by state of occurrence. Women undergoing an abortion were likely to be young (i.e., age < 25 years), white, and unmarried; slightly more than one half were obtaining an abortion for the first time. Of all abortions for which gestational age was reported, 56% were performed at < or = 8 weeks of gestation, and 88% were performed before 13 weeks. Overall, 19% of abortions were performed at the earliest weeks of gestation (< or = 6 weeks), 18% at 7 weeks, and 19% at 8 weeks. From 1992 (when this information was first collected) through 1998, an increasing percentage of abortions were performed at the very early weeks of gestation. Few abortions were provided after 15 weeks of gestation; 4% were obtained at 16-20 weeks, and 1.4% were obtained at > or = 21 weeks. A total of 24 reporting areas submitted information stating that they performed medical (nonsurgical) procedures (two of these areas categorized medical abortions with "other" procedures), making up < 1% of all procedures reported from all states. From 1993 through 1997 (years for which data have not been published previously and the most recent years for which such data are available), 36 women died as a result of complications from known legal induced abortion, and three deaths were associated with known illegal abortion. The annual case-fatality rate of legal induced abortion ranged from 0.3 to 0.8 abortion-related deaths per 100,000 reported legal induced abortions. From 1990 through 1995, the number of abortions declined each year; in 1996, the number increased slightly, but in 1997, it declined to its lowest level since 1978. In 1998, the number of abortions continued to decrease when comparing the 48 reporting areas. In 1997, as in previous years, deaths related to legal induced abortions occurred rarely. PUBLIC HEALTH ACTIONS TAKEN: The number and characteristics of women who obtain abortions in the United States should continue to be monitored so that trends in induced abortion can be assessed and efforts to prevent unintended pregnancy can be evaluated.

Clinical implementation and evaluation of the Acuros dose calculation algorithm.

PubMed

Yan, Chenyu; Combine, Anthony G; Bednarz, Greg; Lalonde, Ronald J; Hu, Bin; Dickens, Kathy; Wynn, Raymond; Pavord, Daniel C; Saiful Huq, M

2017-09-01

The main aim of this study is to validate the Acuros XB dose calculation algorithm for a Varian Clinac iX linac in our clinics, and subsequently compare it with the wildely used AAA algorithm. The source models for both Acuros XB and AAA were configured by importing the same measured beam data into Eclipse treatment planning system. Both algorithms were validated by comparing calculated dose with measured dose on a homogeneous water phantom for field sizes ranging from 6 cm × 6 cm to 40 cm × 40 cm. Central axis and off-axis points with different depths were chosen for the comparison. In addition, the accuracy of Acuros was evaluated for wedge fields with wedge angles from 15 to 60°. Similarly, variable field sizes for an inhomogeneous phantom were chosen to validate the Acuros algorithm. In addition, doses calculated by Acuros and AAA at the center of lung equivalent tissue from three different VMAT plans were compared to the ion chamber measured doses in QUASAR phantom, and the calculated dose distributions by the two algorithms and their differences on patients were compared. Computation time on VMAT plans was also evaluated for Acuros and AAA. Differences between dose-to-water (calculated by AAA and Acuros XB) and dose-to-medium (calculated by Acuros XB) on patient plans were compared and evaluated. For open 6 MV photon beams on the homogeneous water phantom, both Acuros XB and AAA calculations were within 1% of measurements. For 23 MV photon beams, the calculated doses were within 1.5% of measured doses for Acuros XB and 2% for AAA. Testing on the inhomogeneous phantom demonstrated that AAA overestimated doses by up to 8.96% at a point close to lung/solid water interface, while Acuros XB reduced that to 1.64%. The test on QUASAR phantom showed that Acuros achieved better agreement in lung equivalent tissue while AAA underestimated dose for all VMAT plans by up to 2.7%. Acuros XB computation time was about three times faster than AAA for VMAT plans, and computation time for other plans will be discussed at the end. Maximum difference between dose calculated by AAA and dose-to-medium by Acuros XB (Acuros_D m,m ) was 4.3% on patient plans at the isocenter, and maximum difference between D 100 calculated by AAA and by Acuros_D m,m was 11.3%. When calculating the maximum dose to spinal cord on patient plans, differences between dose calculated by AAA and Acuros_D m,m were more than 3%. Compared with AAA, Acuros XB improves accuracy in the presence of inhomogeneity, and also significantly reduces computation time for VMAT plans. Dose differences between AAA and Acuros_D w,m were generally less than the dose differences between AAA and Acuros_D m,m . Clinical practitioners should consider making Acuros XB available in clinics, however, further investigation and clarification is needed about which dose reporting mode (dose-to-water or dose-to-medium) should be used in clinics. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Shared Genetic Risk Factors of Intracranial, Abdominal, and Thoracic Aneurysms.

PubMed

van 't Hof, Femke N G; Ruigrok, Ynte M; Lee, Cue Hyunkyu; Ripke, Stephan; Anderson, Graig; de Andrade, Mariza; Baas, Annette F; Blankensteijn, Jan D; Böttinger, Erwin P; Bown, Matthew J; Broderick, Joseph; Bijlenga, Philippe; Carrell, David S; Crawford, Dana C; Crosslin, David R; Ebeling, Christian; Eriksson, Johan G; Fornage, Myriam; Foroud, Tatiana; von Und Zu Fraunberg, Mikael; Friedrich, Christoph M; Gaál, Emília I; Gottesman, Omri; Guo, Dong-Chuan; Harrison, Seamus C; Hernesniemi, Juha; Hofman, Albert; Inoue, Ituro; Jääskeläinen, Juha E; Jones, Gregory T; Kiemeney, Lambertus A L M; Kivisaari, Riku; Ko, Nerissa; Koskinen, Seppo; Kubo, Michiaki; Kullo, Iftikhar J; Kuivaniemi, Helena; Kurki, Mitja I; Laakso, Aki; Lai, Dongbing; Leal, Suzanne M; Lehto, Hanna; LeMaire, Scott A; Low, Siew-Kee; Malinowski, Jennifer; McCarty, Catherine A; Milewicz, Dianna M; Mosley, Thomas H; Nakamura, Yusuke; Nakaoka, Hirofumi; Niemelä, Mika; Pacheco, Jennifer; Peissig, Peggy L; Pera, Joanna; Rasmussen-Torvik, Laura; Ritchie, Marylyn D; Rivadeneira, Fernando; van Rij, Andre M; Santos-Cortez, Regie Lyn P; Saratzis, Athanasios; Slowik, Agnieszka; Takahashi, Atsushi; Tromp, Gerard; Uitterlinden, André G; Verma, Shefali S; Vermeulen, Sita H; Wang, Gao T; Han, Buhm; Rinkel, Gabriël J E; de Bakker, Paul I W

2016-07-14

Intracranial aneurysms (IAs), abdominal aortic aneurysms (AAAs), and thoracic aortic aneurysms (TAAs) all have a familial predisposition. Given that aneurysm types are known to co-occur, we hypothesized that there may be shared genetic risk factors for IAs, AAAs, and TAAs. We performed a mega-analysis of 1000 Genomes Project-imputed genome-wide association study (GWAS) data of 4 previously published aneurysm cohorts: 2 IA cohorts (in total 1516 cases, 4305 controls), 1 AAA cohort (818 cases, 3004 controls), and 1 TAA cohort (760 cases, 2212 controls), and observed associations of 4 known IA, AAA, and/or TAA risk loci (9p21, 18q11, 15q21, and 2q33) with consistent effect directions in all 4 cohorts. We calculated polygenic scores based on IA-, AAA-, and TAA-associated SNPs and tested these scores for association to case-control status in the other aneurysm cohorts; this revealed no shared polygenic effects. Similarly, linkage disequilibrium-score regression analyses did not show significant correlations between any pair of aneurysm subtypes. Last, we evaluated the evidence for 14 previously published aneurysm risk single-nucleotide polymorphisms through collaboration in extended aneurysm cohorts, with a total of 6548 cases and 16 843 controls (IA) and 4391 cases and 37 904 controls (AAA), and found nominally significant associations for IA risk locus 18q11 near RBBP8 to AAA (odds ratio [OR]=1.11; P=4.1×10(-5)) and for TAA risk locus 15q21 near FBN1 to AAA (OR=1.07; P=1.1×10(-3)). Although there was no evidence for polygenic overlap between IAs, AAAs, and TAAs, we found nominally significant effects of two established risk loci for IAs and TAAs in AAAs. These two loci will require further replication. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Genetic analysis of abdominal aortic aneurysms (AAA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

St. Jean, P.L.; Hart, B.K.; Zhang, X.C.

1994-09-01

The association between AAA and gender, smoking (SM), hypertension (HTN) and inguinal herniation (IH) was examined in 141 AAA probands and 139 of their 1st degree relatives with aortic exam (36 affected, 103 unaffected). There was no significant difference between age at diagnosis of affecteds and age at exam of unaffecteds. Of 181 males, 142 had AAA; of 99 females, 35 had AAA. Using log-linear modeling AAA was significantly associated at the 5% level with gender, SM and HTN but not IH. The association of AAA with SM and HTN held when males and females were analyzed separately. HTN wasmore » -1.5 times more common in both affected males and females, while SM was 1.5 and 2 times more common in affected males and females, respectively. Tests of association and linkage analyses were performed with relevant candidate genes: 3 COL3A1 polymorphisms (C/T, ALA/THR, AvaII), 2 ELN polymorphisms (SER/GLY, (CA)n), FBN1(TAAA)n, 2 APOB polymorphisms (Xbal,Ins/Del), CLB4B (CA)n, PI and markers D1S243 (CA)n, HPR (CA)n and MFD23(CA)n. The loci were genotyped in > 100 AAA probands and > 95 normal controls. No statistically significant evidence of association at the 5% level was obtained for any of the loci using chi-square test of association. 28 families with 2 or more affecteds were analyzed using the affected pedigree member method (APM) and lod-score analyses. There was no evidence for linkage with any loci using APM. Lod-score analysis under an autosomal recessive model resulted in excluding linkage (lod score < -2) of all loci to AAA at {theta}=0.0. Under an autosomal dominant model, linkage was excluded at {theta}=0.0 to ELN, APOB, CLG4B, D1S243, HPR and MFD23. The various genes previously proposed in AAA pathogenesis are neither associated nor casually related in our study population.« less

Characterization of the mechanical behavior and pathophysiological state of abdominal aortic aneurysms based on 4D ultrasound strain imaging

NASA Astrophysics Data System (ADS)

Wittek, Andreas; Blase, Christopher; Derwich, Wojciech; Schmitz-Rixen, Thomas; Fritzen, Claus-Peter

2017-06-01

Abdominal aortic aneurysms (AAA) are a degenerative disease of the human aortic wall that may lead to weakening and eventually rupture of the wall with high mortality rates. Since the currently established criterion for surgical or endovascular treatment of the disease is imprecise in the individual case and treatment is not free of complications, the need for additional patient-individual biomarkers for short-term AAA rupture risk as basis for improved clinical decision making. Time resolved 3D ultrasound combined with speckle tracking algorithms is a novel non-invasive medical imaging technique that provides full-field displacement and strain measurements of aortic and aneurysmal wall motion. This is patient-individual information that has not been used so far to assess wall strength and rupture risk. The current study uses simple statistical indices of the heterogeneous spatial distribution of in-plane strain components as biomarkers for the pathological state of the aortic and aneurysmal wall. The pathophysiological rationale behind this approach are the known changes in microstructural composition of the aortic wall with progression of AAA development that results in increased stiffening and heterogeneity of the walls mechanical properties and in decreased wall strength. In a comparative analysis of the aortic wall motion of young volunteers without known cardiovascular diseases, aged arteriosclerotic patients without AAA, and AAA patients, mean values of all in-plane strain components were significantly reduced, and the heterogeneity of circumferential strain was significantly increased in the AAA group compared to both other groups. The capacity of the proposed method to differentiate between wall motion of aged, arteriosclerotic patients and AAA patients is a promising step towards a new method for in vivo assessment of AAA wall strength or stratification of AAA rupture risk as basis for improved clinical decision making on surgical or endovascular treatment of AAA.

Prevalence of abdominal aortic aneurysm (AAA) in a population undergoing computed tomography colonography in Canterbury, New Zealand.

PubMed

Khashram, M; Jones, G T; Roake, J A

2015-08-01

There is compelling level 1 evidence in support of screening men for abdominal aortic aneurysm (AAA) to reduce AAA mortality. However, New Zealand (NZ) lacks data on AAA prevalence, and national screening has not been implemented. The aim of this study was to determine the prevalence of AAA in a population undergoing a computed tomography colonography (CTC) for gastrointestinal symptoms. This was an observational study; all consecutive CTCs performed in three regions of the South Island of NZ over a 4 year period were reviewed. Data on abdominal and thoracic aorta diameters ≥30 mm, and iliac and femoral aneurysms ≥20 mm were recorded. Previous aortic surgical grafts or endovascular stents were also documented. Demographics, survival, and AAA related outcomes were collected and used for analysis. Included were 4,893 scans on 4,644 patients (1,933 men [41.6%], 2,711 women [58.4%]) with a median age of 69.3 years (range 17.0-97.0 years). There were 309 scans on 289 patients (75.4% men) who had either an aneurysm or a previous aortic graft with a median age of 79.6 years (range 57.0-96.0 years). Of these, 223 had a native AAA ≥30 mm. The prevalence of AAA rose with age from 1.3% in men aged 55-64 years, to 9.1% in 65-74 year olds, 16.8% in 75-84 year olds, and 22.0% in ≥85 year olds. The corresponding figures in women were 0.4%, 2%, 3.9%, and 6.2%, respectively. In this observational study, the prevalence of AAA was high and warrants further evaluation. The results acquired help to define a population that may benefit from a national AAA screening programme. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Abdominal Aortic Aneurysm: Novel Mechanisms and Therapies

PubMed Central

Davis, Frank M.; Rateri, Debra L.; Daugherty, Alan

2015-01-01

Purpose of review Abdominal aortic aneurysm (AAA) is a pathological condition of permanent dilation that portends the potentially fatal consequence of aortic rupture. This review emphasizes recent advances in mechanistic insight into aneurysm pathogenesis and potential pharmacologic therapies that are on the horizon for AAAs. Recent Findings An increasing body of evidence demonstrates that genetic factors, including 3p12.3, DAB2IP, LDLr, LRP1, MMP3, TGFβR2 and SORT1 loci, are associated with AAA development. Current human studies and animal models have shown that many leukocytes and inflammatory mediators, such as IL-1, IL-17, TGF-β and angiotensin II, are involved in the pathogenesis of AAAs. Leukocytic infiltration into aortic media leads to smooth muscle cell depletion, generation of reactive oxygen species, and extracellular matrix fragmentation. Recent preclinical investigations into pharmacological therapies for AAAs have provided intriguing insight for roles of microRNAs to regulate many pathological pathways in AAA development. Several large clinical trials are ongoing seeking to translate preclinical findings into therapeutic options. Summary Recent studies have identified many potential mechanisms involved in AAA pathogenesis that provide insight for the development of a medical treatment for this disease. PMID:26352243

CDC Kerala 5: Developmental therapy clinic experience--use of Child Development Centre grading for motor milestones.

PubMed

Nair, M K C; Resmi, V R; Krishnan, Rajee; Harikumaran Nair, G S; Leena, M L; Bhaskaran, Deepa; George, Babu; Russell, Paul Swamidhas Sudhakar

2014-12-01

To document the experiences of the intervention given to children who attended the developmental therapy clinic of Child Development Centre (CDC) Kerala, a specialized clinic for providing developmental intervention/therapy for babies less than two years with developmental delay/disability. All the babies referred to this speciality clinic from developmental screening/evaluation clinics of CDC were registered in the clinic and re-evaluation was done using CDC grading for head holding, sitting, standing, Amiel Tison passive angles, and Trivandrum Developmental Screening Chart (TDSC) 0-2 y. Out of a total of 600 consecutive babies below 2 y with developmental delay/disability referred to developmental therapy clinic, on comparing the test results at enrollment and after 6 mo of intervention, a statistically significant reduction was observed (i) in the 2-4 mo age group with regard to abnormal TDSC (25.5%), (ii) in the 4-8 mo age group with regard to abnormal head holding grade (87.1%) and abnormal TDSC (19.4%), (iii) in the 8-12 mo age group, with regard to abnormal sitting grade (71.7%) and (iv) in the above 12 mo age group with regard to abnormal sitting grade (35.3%) and abnormal standing grade (78.8%). The experience of organizing the developmental intervention/therapy clinic at CDC Kerala has shown that therapy services by developmental therapists in a centre and supportive therapy by mother at home is useful in improving the developmental status of children with developmental delay.

Clostridium difficile colonization and infection in patients with hepatic cirrhosis.

PubMed

Yan, Dong; Chen, Yunbo; Lv, Tao; Huang, Yandi; Yang, Jiezuan; Li, Yongtao; Huang, Jianrong; Li, Lanjuan

2017-10-01

The aim of this study was to investigate the toxigenic Clostridium difficile colonization (CDC, colonization with toxigenic C. difficile but without symptoms) and C. difficile infection (CDI, active C. difficile infection resulting in disease symptoms) in hepatic cirrhosis patients, identify the risk factors of CDC, and determine the correlation between CDC and CDI. The strains of toxigenic C. difficile were isolated from patients with hepatic cirrhosis within 48 h after admission, followed by multilocus sequence typing (MLST). Patients were divided into toxigenic CDC group and noncolonized (NC) group according to the colonization. Logistic regression analysis was performed to analyse the risk factors for the CDC. Besides, the CDI incidence was compared between the two groups. Colonization of toxigenic C. difficile was identified in 104 cases (19.8 %). Eighteen sequence types (STs) were identified, among which ST-3, ST-54, ST-35 and ST-37 were the predominant types. Child-Pugh class C(relative risk, RR, 3.025; 95 % CI: 1.410-6.488), decrease of prothrombin time activity (PTA) (RR 2.180; 95 % CI: 1.368-3.476), decrease of platelet (RR 2.746; 95 % CI: 0.931-8.103) and concurrent hepatic encephalopathy (RR 1.740; 95 % CI: 1.012-2.990) were identified as the risk factors for the hepatic cirrhosis patients with CDC. The CDI incidence in the CDC group was also significantly higher than that of the NC group (26.0 % vs 1.7 %, P<0.001). An carriage rate of 19.8 % was reported in the hepatic cirrhosis patients with C. difficile colonization. Child's class C, decrease of PTA and platelet, and concurrent hepatic encephalopathy were the risk factors for the hepatic cirrhosis patients with C. difficile colonization. Hepatic cirrhosis patients with C. difficile colonization were more susceptible to CDI.

The preventive and curative effects of melatonin against abdominal aortic aneurysm in rats.

PubMed

Tekin, Gözde; İsbir, Selim; Şener, Göksel; Çevik, Özge; Çetinel, Şule; Dericioğlu, Okan; Arsan, Sinan; Çobanoğlu, Adnan

2018-05-01

Oxygen free radicals are important components involved in the histopathologic tissue alterations observed during abdominal aortic aneurysms (AAAs). This study examined whether melatonin has protective or therapeutic effects against AAAs. Sprague-Dawley rats were divided into four groups. A CaCl 2 model was used to induce AAA. Starting on the operation day (Mel+AAA+Mel group) or 4 weeks after the operation (AAA+Mel group), the rats received intraperitoneal melatonin (10 mg/kg/day) for 6 and 2 weeks, respectively. The control and AAA groups received vehicle for 2 weeks after the sham operation and AAA induction, respectively. Angiographic measurements were recorded at the beginning, week 4, and week 6 of the study. After decapitation, aorta tissues were taken for the measurement of malondialdehyde, 8-hydroxy-2'-deoxyguanosine, glutathione levels, and myeloperoxidase and caspase-3 activity. Matrix metalloproteinase (MMP)-2, MMP-9, tumor necrosis factor-α, and inducible nitric oxide synthase protein expressions were analyzed by Western blot technique. Aortic tissues were also examined by light microscopy. CaCl 2 caused an inflammatory response and oxidative damage indicated by rises in malondialdehyde and 8-hydroxy-2'-deoxyguanosine levels. Myeloperoxidase and caspase-3 activities were increased, but glutathione levels were reduced. On the one hand, MMP-2, MMP-9, tumor necrosis factor-α, and inducible nitric oxide synthase protein expressions were increased in the vehicle-treated AAA group. On the other hand, melatonin treatment reversed all of these biochemical indices and histopathologic alterations. According to the data, although melatonin tended to reverse the biochemical parameters given on week 4, the preventive effect is more pronounced when given concomitantly with AAA induction because values were closer to the control levels. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Awake Craniotomy Anesthesia: A Comparison of the Monitored Anesthesia Care and Asleep-Awake-Asleep Techniques.

PubMed

Eseonu, Chikezie I; ReFaey, Karim; Garcia, Oscar; John, Amballur; Quiñones-Hinojosa, Alfredo; Tripathi, Punita

2017-08-01

Commonly used sedation techniques for an awake craniotomy include monitored anesthesia care (MAC), using an unprotected airway, and the asleep-awake-asleep (AAA) technique, using a partially or totally protected airway. We present a comparative analysis of the MAC and AAA techniques, evaluating anesthetic management, perioperative outcomes, and complications in a consecutive series of patients undergoing the removal of an eloquent brain lesion. Eighty-one patients underwent awake craniotomy for an intracranial lesion over a 9-year period performed by a single-surgeon and a team of anesthesiologists. Fifty patients were treated using the MAC technique, and 31 were treated using the AAA technique. A retrospective analysis evaluated anesthetic management, intraoperative complications, postoperative outcomes, pain management, and complications. The MAC and AAA groups had similar preoperative patient and tumor characteristics. Mean operative time was shorter in the MAC group (283.5 minutes vs. 313.3 minutes; P = 0.038). Hypertension was the most common intraoperative complication seen (8% in the MAC group vs. 9.7% in the AAA group; P = 0.794). Intraoperative seizure occurred at a rate of 4% in the MAC group and 3.2% in the AAA group (P = 0.858). Awake cases were converted to general anesthesia in no patients in the MAC group and in 1 patient (3.2%) in the AAA group (P = 0.201). No cases were aborted in either group. The mean hospital length of stay was 3.98 days in the MAC group and 3.84 days in the AAA group (P = 0.833). Both the MAC and AAA sedation techniques provide an efficacious and safe method for managing awake craniotomy cases and produce similar perioperative outcomes, with the MAC technique associated with shorter operative time. Copyright © 2017 Elsevier Inc. All rights reserved.

Ultraviolet B Exposure Inhibits Angiotensin II-Induced Abdominal Aortic Aneurysm Formation in Mice by Expanding CD4+Foxp3+ Regulatory T Cells.

PubMed

Hayashi, Tomohiro; Sasaki, Naoto; Yamashita, Tomoya; Mizoguchi, Taiji; Emoto, Takuo; Amin, Hilman Zulkifli; Yodoi, Keiko; Matsumoto, Takuya; Kasahara, Kazuyuki; Yoshida, Naofumi; Tabata, Tokiko; Kitano, Naoki; Fukunaga, Atsushi; Nishigori, Chikako; Rikitake, Yoshiyuki; Hirata, Ken-Ichi

2017-08-31

Pathogenic immune responses are known to play an important role in abdominal aortic aneurysm (AAA) development. Ultraviolet B (UVB) irradiation has been demonstrated to have therapeutic potential not only for cutaneous diseases but also for systemic inflammatory diseases in mice by suppressing immunoinflammatory responses. We investigated the effect of UVB irradiation on experimental AAA. We used an angiotensin II-induced AAA model in apolipoprotein E-deficient mice fed a high-cholesterol diet. Mice aged 10 weeks were irradiated with 5 kJ/m 2 UVB once weekly for 6 weeks (UVB-irradiated, n=38; nonirradiated, n=42) and were euthanized for evaluation of AAA formation at 16 weeks. Overall, 93% of angiotensin II-infused mice developed AAA, with 60% mortality possibly because of aneurysm rupture. UVB irradiation significantly decreased the incidence (66%) and mortality (29%) of AAA ( P =0.004 and P =0.006, respectively). UVB-irradiated mice had significantly smaller diameter AAA ( P =0.008) and fewer inflammatory cells in the aortic aneurysm tissue than nonirradiated mice, along with systemic expansion of CD4 + Foxp3 + regulatory T cells and decreased effector CD4 + CD44 high CD62L low T cells in para-aortic lymph nodes. Genetic depletion of regulatory T cells abrogated these beneficial effects of UVB treatment, demonstrating a critical role of regulatory T cells. Our data suggest that UVB-dependent expansion of regulatory T cells has beneficial effects on experimental AAA and may provide a novel strategy for the treatment of AAA. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Oxidative Stress in Aortas of Patients with Advanced Occlusive and Aneurysmal Diseases.

PubMed

Lucas, Márcio L; Carraro, Cristina C; Belló-Klein, Adriane; Kalil, Antônio N; Aerts, Newton R; Carvalho, Fabiano B; Fernandes, Marilda C; Zettler, Claudio G

2018-06-06

Aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA) are very important cardiovascular diseases that present different aspects of pathophysiology; however, oxidative stress and inflammatory response seem be relevant in both of them. Our objective was to evaluate oxidative damage and degree of inflammatory infiltrate in aortas of patients surgically treated for AOD and AAA. Levels of reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and myeloperoxidase (MPO) expression as well as nitrite levels and superoxide dismutase (SOD) and catalase (CAT) activities were evaluated in aortas of patients with AOD (n = 16) or AAA (n = 14), while the control group was formed by cadaveric organ donors (n = 10). We also analyzed the degree of inflammatory infiltrate in these aortas. There was an increase in ROS levels and NADPH oxidase activity in patients with AOD and AAA when compared with the control group, and the AOD group demonstrated higher ROS production and NADPH oxidase activity and also nitrite levels when compared with the AAA group (P < 0.001). On the other hand, an increase of SOD activity in the AOD group and CAT activity in the AAA group was observed. Inflammatory infiltrate and MPO expression were higher in the AOD group when compared with the control group (P < 0.05). Oxidative stress is relevant in both AOD and AAA, though AOD presented higher ROS levels and NADPH activity. Increased activities of antioxidant enzymes may be a compensatory phenomenon which occurs in aortas of patients with AOD and AAA. Perhaps, a relationship between oxidative stress and degree of inflammatory infiltrate may exist in the pathophysiology of AOD and AAA. Copyright © 2018 Elsevier Inc. All rights reserved.

Obesity is not an independent risk factor for adverse perioperative and long-term clinical outcomes following open AAA repair or EVAR.

PubMed

Park, Brian; Dargon, Phong; Binette, Christopher; Babic, Bruna; Thomas, Tina; Divinagracia, Thomas; Dahn, Michael S; Menzoian, James O

2011-10-01

Moderate (body mass index [BMI] ≥30) and morbid obesity (BMI ≥35) is increasing at an alarming rate in vascular surgery patients. The objective of this study was to determine the impact of obesity on perioperative and long-term clinical outcomes following open abdominal aortic aneurysm (AAA) repair or endovascular aneurysm repair (EVAR). This review includes patients that underwent open AAA repair (n = 403) or EVAR (n = 223) from 1999 to 2009. Specific patient characteristics such as comorbid diseases, medications, and body mass index (BMI) were assessed. Specific perioperative outcomes such as length of stay, myocardial infarctions, and mortality were reviewed. In addition, long-term outcomes such as rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days were also assessed. The incidence of obesity in open AAA patients was 25.3% (documented incidence 1.5%) and for EVAR was 24.6% (documented incidence 4%). Moderate and morbid obesity was associated with longer intensive care unit (ICU) admissions for both open AAA or EVAR patients (P < .05). However, no significant differences in perioperative outcomes in terms of overall length of stay, myocardial infarction, acute renal failure, wound infections, or mortality were noted between obese and nonobese patients underoing open AAA repair or EVAR (P > .05). Similarly, moderate and morbid obesity was not associated with significant differences in rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days for patients undergoing open AAA repair or EVAR (P > .05). The results of this study indicate that moderate and morbid obesity are not independently associated with adverse perioperative and long-term clinical outcomes for patients undergoing open AAA repair or EVAR. Therefore, either open AAA repair or EVAR can be accomplished safely in moderately obese and morbidly obese patients.

Role of Interleukin-1 Signaling in a Mouse Model of Kawasaki Disease-Associated Abdominal Aortic Aneurysm.

PubMed

Wakita, Daiko; Kurashima, Yosuke; Crother, Timothy R; Noval Rivas, Magali; Lee, Youngho; Chen, Shuang; Fury, Wen; Bai, Yu; Wagner, Shawn; Li, Debiao; Lehman, Thomas; Fishbein, Michael C; Hoffman, Hal M; Shah, Prediman K; Shimada, Kenichi; Arditi, Moshe

2016-05-01

Kawasaki disease (KD) is the most common cause of acquired cardiac disease in US children. In addition to coronary artery abnormalities and aneurysms, it can be associated with systemic arterial aneurysms. We evaluated the development of systemic arterial dilatation and aneurysms, including abdominal aortic aneurysm (AAA) in the Lactobacillus casei cell-wall extract (LCWE)-induced KD vasculitis mouse model. We discovered that in addition to aortitis, coronary arteritis and myocarditis, the LCWE-induced KD mouse model is also associated with abdominal aorta dilatation and AAA, as well as renal and iliac artery aneurysms. AAA induced in KD mice was exclusively infrarenal, both fusiform and saccular, with intimal proliferation, myofibroblastic proliferation, break in the elastin layer, vascular smooth muscle cell loss, and inflammatory cell accumulation in the media and adventitia. Il1r(-/-), Il1a(-/-), and Il1b(-/-) mice were protected from KD associated AAA. Infiltrating CD11c(+) macrophages produced active caspase-1, and caspase-1 or NLRP3 deficiency inhibited AAA formation. Treatment with interleukin (IL)-1R antagonist (Anakinra), anti-IL-1α, or anti-IL-1β mAb blocked LCWE-induced AAA formation. Similar to clinical KD, the LCWE-induced KD vasculitis mouse model can also be accompanied by AAA formation. Both IL-1α and IL-1β play a key role, and use of an IL-1R blocking agent that inhibits both pathways may be a promising therapeutic target not only for KD coronary arteritis, but also for the other systemic arterial aneurysms including AAA that maybe seen in severe cases of KD. The LCWE-induced vasculitis model may also represent an alternative model for AAA disease. © 2016 American Heart Association, Inc.

Evaluation of the relationship between plasma lipids and abdominal aortic aneurysm: A Mendelian randomization study.

PubMed

Weng, Lu-Chen; Roetker, Nicholas S; Lutsey, Pamela L; Alonso, Alvaro; Guan, Weihua; Pankow, James S; Folsom, Aaron R; Steffen, Lyn M; Pankratz, Nathan; Tang, Weihong

2018-01-01

Studies have reported that higher circulating levels of total cholesterol (TC), low-density lipoprotein (LDL) cholesterol and lower of high-density lipoprotein (HDL) cholesterol may be associated with increased risk of abdominal aortic aneurysm (AAA). Whether dyslipidemia causes AAA is still unclear and is potentially testable using a Mendelian randomization (MR) approach. We investigated the associations between blood lipids and AAA using two-sample MR analysis with SNP-lipids association estimates from a published genome-wide association study of blood lipids (n = 188,577) and SNP-AAA association estimates from European Americans (EAs) of the Atherosclerosis Risk in Communities (ARIC) study (n = 8,793). We used inverse variance weighted (IVW) MR as the primary method and MR-Egger regression and weighted median MR estimation as sensitivity analyses. Over a median of 22.7 years of follow-up, 338 of 8,793 ARIC participants experienced incident clinical AAA. Using the IVW method, we observed positive associations of plasma LDL cholesterol and TC with the risk of AAA (odds ratio (OR) = 1.55, P = 0.02 for LDL cholesterol and OR = 1.61, P = 0.01 for TC per 1 standard deviation of lipid increment). Using the MR-Egger regression and weighted median methods, we were able to validate the association of AAA risk with TC, although the associations were less consistent for LDL cholesterol due to wider confidence intervals. Triglycerides and HDL cholesterol were not associated with AAA in any of the MR methods. Assuming instrumental variable assumptions are satisfied, our finding suggests that higher plasma TC and LDL cholesterol are causally associated with the increased risk of AAA in EAs.

Time-specific and population-level differences in physiological responses of fathead minnows (Pimephales promelas) and golden shiners (Notemigonus crysoleucas) exposed to copper.

PubMed

Peles, John D; Pistole, David H; Moffe, Mickey C

2012-03-01

The influence of exposure time on gill Na+/K+ ATPase activity and metabolic rate in populations of fathead minnows (Pimephales promelas) and golden shiners (Notemigonus crysoleucas) hatcheries in Ohio (OH) and Pennsylvania (PA) when exposed to sublethal concentrations of copper (Cu) was examined. The pattern of change in gill Na+/K+ ATPase activity was similar in all species/populations and results support expectations based on the concept of acclimation. In all populations, Na+/K+ ATPase activity declined significantly compared to reference values within 24 h, recovered by 48 h, and then continued to increase before exceeding reference values by 192 h. With the exception of PA fathead minnows, Na+/K+ ATPase activities returned to reference levels by 384 h. Although metabolic rates of individual fish were not strongly correlated with Na+/K+ ATPase activities, the pattern of change in mean values of these physiological parameters was very similar. However, OH populations of both fathead minnows and golden shiners demonstrated much more dramatic changes in metabolic rate compared to PA fish. At 24 h, metabolic rate of PA fathead minnows had decreased by 16% compared to the reference value whereas the OH population had decreased by 31%; metabolic rate of PA golden shiners declined by 23% compared to 59% in OH shiners at 24 h. Similar differences were observed in the maximum metabolic rates achieved at 192 h. While the increased sensitivity of OH fish to Cu is not readily explainable by genetic or environmental factors, results suggest the need for considering population level differences when evaluating the physiological effects of toxicants. Copyright © 2011 Elsevier B.V. All rights reserved.

Impact of surgeon and hospital experience on outcomes of abdominal aortic aneurysm repair in New York State.

PubMed

Meltzer, Andrew J; Connolly, Peter H; Schneider, Darren B; Sedrakyan, Art

2017-09-01

This study aimed to assess the impact of the surgeon's and hospital's experience on the outcomes of open surgical repair (OSR) and endovascular aneurysm repair (EVAR) of intact and ruptured abdominal aortic aneurysms (AAAs) in New York State. New York Statewide Planning and Research Cooperative System data were used to identify patients undergoing AAA repair from 2000 to 2011. Characteristics of the provider and hospital were determined by linkage to the New York Office of Professions and National Provider Identification databases. Distinct hierarchical logistic regression models for EVAR and OSR for intact and ruptured AAAs were created to adjust for the patient's comorbidities and to evaluate the impact of the surgeon's and hospital's experience on outcomes. The provider's years since medical school graduation as well as annual volume of the facility and provider are examined in tertiles. Adjusted odds ratios and 95% confidence intervals are presented. A total of 18,842 patients underwent AAA repair by a vascular surgeon. For intact AAAs (n = 17,118), 26.2% of patients underwent OSR and 73.8% underwent EVAR. For ruptured AAAs (n = 1724), 63.9% underwent OSR and 36.1% underwent EVAR. After intact AAA repair, OSR adjusted outcomes were significantly influenced by the surgeon's annual volume but not by the facility's volume or the surgeon's age. The lowest volume providers (1-4 OSRs) had higher in-hospital mortality rates than high-volume (>11 OSRs) surgeons (adjusted odds ratio, 1.87 [95% confidence interval, 1.1-3.17]). Low-volume providers also had higher odds of major complications (1.23 [1-1.51]). For patients with intact AAA undergoing EVAR, mortality was higher at low-volume facilities (2.6 [1.3-5.3] and 2.7 [1.5-4.8] for <33 EVARs and 34-81 EVARs, respectively). After OSR for ruptured AAA, treatment at a low-volume facility (<9 OSRs for ruptured AAA) was associated with greater mortality than at high-volume (>27 OSRs for ruptured AAA) centers (1.56 [1.02-2.39]), whereas low-volume physicians (<4 OSRs for ruptured AAA) had higher odds of major complications (1.58 [1.04-2.41]). In the case of EVAR for rupture, there were no characteristics of the hospital or surgeon significantly associated with poorer outcomes. For intact AAA, the surgeon's volume was an important factor for OSR outcomes, whereas low facility volume was associated with worse outcomes after EVAR. For ruptured AAA, low-volume surgeons and low-volume facilities had worse outcomes after OSR but not after EVAR. The interaction between the surgeon's volume and the hospital's volume is complex and varies on the basis of the acuity of presentation and treatment modality. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Abdominal aortic aneurysms: an autoimmune disease?

PubMed

Jagadesham, Vamshi P; Scott, D Julian A; Carding, Simon R

2008-12-01

Abdominal aortic aneurysms (AAAs) are a multifactorial degenerative vascular disorder. One of the defining features of the pathophysiology of aneurysmal disease is inflammation. Recent developments in vascular and molecular cell biology have increased our knowledge on the role of the adaptive and innate immune systems in the initiation and propagation of the inflammatory response in aortic tissue. AAAs share many features of autoimmune disease, including genetic predisposition, organ specificity and chronic inflammation. Here, this evidence is used to propose that the chronic inflammation observed in AAAs is a consequence of a dysregulated autoimmune response against autologous components of the aortic wall that persists inappropriately. Identification of the molecular and cellular targets involved in AAA formation will allow the development of therapeutic agents for the treatment of AAA.

Pathophysiology of AAA: heredity vs environment.

PubMed

Björck, Martin; Wanhainen, Anders

2013-01-01

Abdominal aortic aneurysm (AAA) has a complex pathophysiology, in which both environmental and genetic factors play important roles, the most important being smoking. The recently reported falling prevalence rates of AAA in northern Europe and Australia/New Zeeland are largely explained by healthier smoking habits. Dietary factors and obesity, in particular abdominal obesity, are also of importance. A family history of AAA among first-degree relatives is present in approximately 13% of incident cases. The probability that a monozygotic twin of a person with an AAA has the disease is 24%, 71 times higher than that for a monozygotic twin of a person without AAA. Approximately 1000 SNPs in 100 candidate genes have been studied, and three genome-wide association studies were published, identifying different diverse weak associations. An example of interaction between environmental and genetic factors is the effect of cholesterol, where genetic and dietary factors affect levels of both HDL and LDL. True epigenetic studies have not yet been published. Copyright © 2013 Elsevier Inc. All rights reserved.

Gender Differences in CDC Guideline Compliance for STIs in Emergency Departments.

PubMed

Kane, Bryan G; Guillaume, Alexander W D; Evans, Elizabeth M; Goyke, Terrence E; Eygnor, Jessica K; Semler, Lauren; Dusza, Stephen W; Greenberg, Marna Rayl

2017-04-01

Sexually transmitted infections (STIs) are a common reason for emergency department (ED) visits. The objective of this study was to determine if there were gender differences in adherence to Centers for Disease Control and Prevention (CDC) STI diagnosis and treatment guidelines, as documented by emergency providers. We performed a retrospective chart review to identify patients treated for urethritis, cervicitis, and pelvic inflammatory disease (PID) in the EDs of three hospitals in a Pennsylvania network during a calendar year. Cases were reviewed to assess for compliance with CDC guidelines. We used descriptive statistics to assess the distributions of study variables by patient sex. In the analysis we used Student's t-tests, chi-square tests, and logistic regression. Statistical significance was set at p ≤ 0.05. We identified 286 patient records. Of these, we excluded 39 for the following reasons: incorrect disease coding; the patient was admitted and treated as an inpatient for his/her disease; or the patient left the ED after refusing care. Of the 247 participants, 159 (64.4%) were female. Females were significantly younger (26.6 years, SD=8.0) than males (31.2, SD=11.5%), (95% confidence interval [CI] [2.0- 7.0], p=0.0003). All of the males (n=88) in the cohort presented with urethritis; 25.8% of females presented with cervicitis, and 74.2% with PID. Physician compliance for the five CDC criteria ranged from 68.8% for patient history to 93.5% for patient diagnostic testing, including urine pregnancy and gonorrhea/chlamydia cultures. We observed significant differences by patient sex. Fifty-four percent of the charts had symptoms recorded for female patients that were consistent with CDC characteristics for diagnostic criteria compared to over 95% for males, OR=16.9; 95% CI [5.9-48.4], p<0.001. Similar results were observed for patient discharge instructions, with physicians completely documenting delivery of discharge instructions to 51.6% of females compared to 97.7% of complete documentation in males, OR=42.3; 95% CI [10.0-178.6] p<0.001). We observed no significant sex differences in physician documentation for physical exam or for therapeutic antibiotic treatment. This retrospective study found patient gender differences in how emergency providers complied with documenting with regard to the 2010 CDC guidelines for the diagnosis and treatment of urethritis, cervicitis, and PID. Specifically medical records of men were more likely to have complete documentation of symptoms recorded (95% CI 5.9-48.4) and to have discharge instruction documentation (95% CI 10.0-178.6) than records of women.

Outcomes for Symptomatic Abdominal Aortic Aneurysms in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP)

PubMed Central

Soden, Peter A.; Zettervall, Sara L.; Ultee, Klaas H.J.; Darling, Jeremy D.; Buck, Dominique B.; Hile, Chantel N.; Hamdan, Allen D.; Schermerhorn, Marc L.

2016-01-01

Introduction Historically symptomatic AAAs were found to have intermediate mortality compared to asymptomatic and ruptured AAAs but, with wider EVAR use, a more recent study suggested mortality of symptomatic aneurysms were similar to asymptomatic AAAs. These prior studies were limited by small numbers. The purpose of this study is to evaluate the mortality and morbidity associated with symptomatic AAA repair in a large contemporary population. Methods All patients undergoing infrarenal AAA repair were identified in the 2011–2013 ACS-NSQIP, Vascular Surgery targeted module. We excluded acute conversions to open repair and those for whom the surgical indication was embolization, dissection, thrombosis, or not documented. We compared 30-day mortality and major adverse events (MAE) for asymptomatic, symptomatic, and ruptured AAA repair, stratified by EVAR and open repair, with univariate analysis and multivariable logistic regression. Results 5502 infrarenal AAAs were identified, 4495 asymptomatic (830 open repair, 3665 [82%] EVAR), 455 symptomatic (143 open, 312 [69%] EVAR), and 552 ruptured aneurysms (263 open, 289 [52%] EVAR). Aneurysm diameter was similar between asymptomatic and symptomatic AAAs, when stratified by procedure type, but larger for ruptured aneurysms (EVAR symptomatic 5.8cm ±1.6 vs. ruptured 7.5cm ±2.0, P<.001; open repair symptomatic 6.4cm ±1.9 vs. ruptured 8.0cm ±1.9, P<.001). The proportion of females was similar in symptomatic and ruptured AAA (27% vs. 23%, P=.14, respectively), but lower in asymptomatic AAA (20%, P<.001). Symptomatic AAAs had intermediate 30-day mortality compared to asymptomatic and ruptured aneurysms after both EVAR (asymptomatic 1.4% vs. symptomatic 3.8%, P=.001; symptomatic vs. 22% ruptured, P<.001) and open repair (asymptomatic 4.3% vs. symptomatic 7.7% , P=.08; symptomatic vs. 57% ruptured, P<.001). After adjustment for age, gender, repair type, dialysis dependence, and history of severe COPD, patients undergoing repair of symptomatic AAAs were twice as likely to die within 30-days compared to those with asymptomatic aneurysms (OR 2.1, 95%CI 1.3–3.5). When stratified by repair type the effect size and direction of the odds ratios were similar (EVAR OR 2.4, CI 1.2–4.7; open repair OR 1.8, CI 0.86–3.9), although not significant for open repair. Patients with ruptured aneurysms had a sevenfold increased risk of 30-day mortality compared to symptomatic patients (OR 6.5, CI 4.1–10.6). Conclusion Patients with symptomatic AAAs had a two-fold increased risk of perioperative mortality, compared to asymptomatic aneurysms undergoing repair. Furthermore, patients with ruptured aneurysms have a seven-fold increased risk of mortality compared to symptomatic aneurysms. PMID:27146791

Simultaneous repair of abdominal aortic aneurysm and resection of unexpected, associated abdominal malignancies.

PubMed

Illuminati, Giulio; Calio', Francesco G; D'Urso, Antonio; Lorusso, Riccardo; Ceccanei, Gianluca; Vietri, Francesco

2004-12-15

The management of unexpected intra-abdominal malignancy, discovered at laparotomy for elective treatment of an abdominal aortic aneurysm (AAA), is controversial. It is still unclear whether both conditions should be treated simultaneously or a staged approach is to be preferred. To contribute in improving treatment guidelines, we retrospectively reviewed the records of patients undergoing laparotomy for elective AAA repair. From January 1994 to March 2003, 253 patients underwent elective, trans-peritoneal repair of an AAA. In four patients (1.6%), an associated, unexpected neoplasm was detected at abdominal exploration, consisting of one renal, one gastric, one ileal carcinoid, and one ascending colon tumor. All of them were treated at the same operation, after aortic repair and careful isolation of the prosthetic graft. The whole series' operative mortality was 3.6%. None of the patients simultaneously treated for AAA and tumor resection died in the postoperative period. No graft-related infections were observed. Simultaneous treatment of AAA and tumor did not prolong significantly the mean length of stay in the hospital, compared to standard treatment of AAA alone. Except for malignancies of organs requiring major surgical resections, simultaneous AAA repair and resection of an associated, unexpected abdominal neoplasm can be safely performed, in most of the patients, sparing the need for a second procedure. Endovascular grafting of the AAA can be a valuable tool in simplifying simultaneous treatment, or in staging the procedures with a very short delay.

Functional characterization of T cells in abdominal aortic aneurysms.

PubMed

Forester, Nerys D; Cruickshank, Sheena M; Scott, D Julian A; Carding, Simon R

2005-06-01

Abdominal aortic aneurysms (AAA) exhibit features of a chronic inflammatory disorder. The functional attributes of the T cells in AAA tissue are unclear, with little quantitative or functional data. Using a novel, non-enzymatic method to isolate viable cells from AAA tissue, functional properties of AAA T cells were investigated for the first time. Composition and phenotype of AAA T cells was determined by flow cytometry and verified by immunohistochemistry. Tissue mononuclear cells (MNCs) were cultured in the presence of T-cell mitogens, and cell cycle analysis and cytokine production assessed. Typical cell yield was 4.5 x 10(6) cells per gram of AAA tissue. The majority (58.1+/-5.3%) of haematopoietic (CD45+) cells recovered were CD3+ T cells, B cells comprised 41.1+/-5.7%, natural killer cells 7.3+/-2.5%, and macrophages 2%. Freshly isolated T cells were in resting (G1) state, with 25% expressing the activation-associated cell surface antigens major histocompatibility complex II and CD25. When stimulated in vitro, a significant proportion entered S and G2 phase of the cell cycle, up-regulated CD25, and secreted tumour necrosis factor-alpha, interferon-gamma, interleukin (IL)-5 and IL-6. Despite patient differences, the composition of the AAA inflammatory infiltrate was remarkably consistent, and when re-stimulated ex-vivo T cells produced a stereotypical cytokine response, consistent with the hypothesis that AAA T cells can promote tissue inflammation by secretion of proinflammatory cytokines, and in addition provide signals for B-cell help.

Distinct Effect of Benzalkonium Chloride on the Esterase and Aryl Acylamidase Activities of Butyrylcholinesterase.

PubMed

Jaganathan; Boopathy

2000-08-01

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) from vertebrates, other than their predominant acylcholine hydrolase (esterase) activity, display a genuine aryl acylamidase activity (AAA) capable of hydrolyzing the synthetic substrate o-nitroacetanilide to o-nitroaniline. This AAA activity is strongly inhibited by classical cholinesterase (ChE) inhibitors. In the present study, benzalkonium chloride (BAC), a cationic detergent widely used as a preservative in pharmaceutical preparations, has been shown to distinctly modulate the esterase and AAA activities of BChEs. The detergent BAC was able to inhibit the esterase activity of human serum and horse serum BChEs and AChEs from electric eel and human erythrocyte. The remarkable property of BAC was its ability to profoundly activate the AAA activity of human serum and horse serum BChEs but not the AAA activity of AChEs. Thus BAC seem to preferentially activate the AAA activity of BChEs alone. Results of the study using the ChE active site-specific inhibitor diisopropyl phosphorofluoridate indicated that BAC binds to the active site of ChEs. Furthermore, studies using a structural homolog of BAC indicated that the alkyl group of BAC is essential not only for its interaction with ChEs but also for its distinct effect on the esterase and AAA activities of BChEs. This is the first report of a compound that inhibits the esterase activity, while simultaneously activating the AAA activity, of BChEs. Copyright 2000 Academic Press.

Peptide inhibitor of CXCL4-CCL5 heterodimer formation, MKEY, inhibits experimental aortic aneurysm initiation and progression.

PubMed

Iida, Yasunori; Xu, Baohui; Xuan, Haojun; Glover, Keith J; Tanaka, Hiroki; Hu, Xiaolei; Fujimura, Naoki; Wang, Wei; Schultz, Joshua R; Turner, Court R; Dalman, Ronald L

2013-04-01

Macrophages are critical contributors to abdominal aortic aneurysm (AAA) disease. We examined the ability of MKEY, a peptide inhibitor of CXCL4-CCL5 interaction, to influence AAA progression in murine models. AAAs were created in 10-week-old male C57BL/6J mice by transient infrarenal aortic porcine pancreatic elastase infusion. Mice were treated with MKEY via intravenous injection either (1) before porcine pancreatic elastase infusion or (2) after aneurysm initiation. Immunostaining demonstrated CCL5 and CCR5 expression on aneurysmal aortae and mural monocytes/macrophages, respectively. MKEY treatment partially inhibited migration of adaptively transferred leukocytes into aneurysmal aortae in recipient mice. Although all vehicle-pretreated mice developed AAAs, aneurysms formed in only 60% (3/5) and 14% (1/7) of mice pretreated with MKEY at 10 and 20 mg/kg, respectively. MKEY pretreatment reduced aortic diameter enlargement, preserved medial elastin fibers and smooth muscle cells, and attenuated mural macrophage infiltration, angiogenesis, and aortic metalloproteinase 2 and 9 expression after porcine pancreatic elastase infusion. MKEY initiated after porcine pancreatic elastase infusion also stabilized or reduced enlargement of existing AAAs. Finally, MKEY treatment was effective in limiting AAA formation after angiotensin II infusion in apolipoprotein E-deficient mice. MKEY suppresses AAA formation and progression in 2 complementary experimental models. Peptide inhibition of CXCL4-CCL5 interactions may represent a viable translational strategy to limit progression of human AAA disease.

SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamichhane, N; Studenski, M

2016-06-15

Purpose: It is essential to assess the lung dose during TBI to reduce toxicity. Here we characterize the accuracy of the AAA and Acuros algorithms when using cerrobend lung shielding blocks at an extended distance for TBI. Methods: We positioned a 30×30×30 cm3 solid water slab phantom at 400 cm SSD and measured PDDs (Exradin A12 and PTW parallel plate ion chambers). A 2 cm thick, 10×10 cm2 cerrobend block was hung 2 cm in front of the phantom. This geometry was reproduced in the planning system for both AAA and Acuros. In AAA, the mass density of the cerrobendmore » block was forced to 9.38 g/cm3 and in Acuros it was forced to 8.0 g/cm3 (limited to selecting stainless steel). Three different relative electron densities (RED) were tested for each algorithm; 4.97, 6.97, and 8.97. Results: PDDs from both Acuros and AAA underestimated the delivered dose. AAA calculated that depth dose was higher for RED of 4.97 as compared to 6.97 and 8.97 but still lower than measured. There was no change in the percent depth dose with changing relative electron densities for Acuros. Conclusion: Care should be taken before using AAA or Acuros with cerrobend blocks as the planning system underestimates dose. Acuros limits the ability to modify RED when compared to AAA.« less

Histopathological analysis of cellular localization of cathepsins in abdominal aortic aneurysm wall.

PubMed

Lohoefer, Fabian; Reeps, Christian; Lipp, Christina; Rudelius, Martina; Zimmermann, Alexander; Ockert, Stefan; Eckstein, Hans-Henning; Pelisek, Jaroslav

2012-08-01

An important feature of abdominal aortic aneurysm (AAA) is the destruction of vessel wall, especially elastin and collagen. Besides matrix metalloproteinases, cathepsins are the most potent elastolytic enzymes. The expression of cathepsins with known elastolytic and collagenolytic activities in the individual cells within AAA has not yet been determined. The vessel wall of 32 AAA patients and 10 organ donors was analysed by immunohistochemistry for expression of cathepsins B, D, K, L and S, and cystatin C in all cells localized within AAA. Luminal endothelial cells (ECs) of AAA were positive for cathepsin D and partially for cathepsins B, K and S. Endothelial cells of the neovessels and smooth muscle cells in the media were positive for all cathepsins tested, especially for cathepsin B. In the inflammatory infiltrate all cathepsins were expressed in the following pattern: B > D = S > K = L. Macrophages showed the highest staining intensity for all cathepsins. Furthermore, weak overall expression of cystatin C was observed in all the cells localized in the AAA with the exception of the ECs. There is markedly increased expression of the various cathepsins within the AAA wall compared to healthy aorta. Our data are broadly consistent with a role for cathepsins in AAA; and demonstrate expression of cathepsins D, B and S in phagocytic cells in the inflammatory infiltrate; and also may reveal a role for cathepsin B in lymphocytes. © 2012 The Authors. International Journal of Experimental Pathology © 2012 International Journal of Experimental Pathology.

Associations of Diabetes and Obesity with Risk of Abdominal Aortic Aneurysm in Men

PubMed Central

Djousse, Luc; Song, Yiqing; Akinkuolie, Akintunde O.; Matsumoto, Chisa; Manson, JoAnn E.; Gaziano, J. Michael; Sesso, Howard D.

2017-01-01

Background. The associations of diabetes and obesity with the risk of abdominal aortic aneurysm (AAA) are inconclusive in previous studies. Subjects/Methods. We conducted prospective analysis in the Physicians' Health Study. Among 25,554 male physicians aged ≥ 50 years who reported no AAA at baseline, 471 reported a newly diagnosed AAA during a mean of 10.4 years' follow-up. Results. Compared with men who had baseline body mass index (BMI) < 25 kg/m2, the multivariable hazard ratio (HR [95% CI]) of newly diagnosed AAA was 1.30 [1.06–1.59] for BMI 25–<30 kg/m2 and 1.69 [1.24–2.30] for BMI ≥ 30 kg/m2. The risk of diagnosed AAA was significantly higher by 6% with each unit increase in baseline BMI. This association was consistent regardless of the other known AAA risk factors and preexisting vascular diseases. Overall, baseline history of diabetes tended to be associated with a lower risk of diagnosed AAA (HR = 0.79 [0.57–1.11]); this association appeared to vary by follow-up time (HR = 1.56 and 0.63 during ≤ and >2 years' follow-up, resp.). Conclusion. In a large cohort of middle-aged and older men, obesity was associated with a higher risk, while history of diabetes tended to associate with a lower risk of diagnosed AAA, particularly over longer follow-up. PMID:28326193

Abortion surveillance--United States, 2002.

PubMed

Strauss, Lilo T; Herndon, Joy; Chang, Jeani; Parker, Wilda Y; Bowens, Sonya V; Berg, Cynthia J

2005-11-25

CDC began abortion surveillance in 1969 to document the number and characteristics of women obtaining legal induced abortions. This report summarizes and describes data voluntarily reported to CDC regarding legal induced abortions obtained in the United States in 2002. For each year since 1969, CDC has compiled abortion data by state or area of occurrence. During 1973-1997, data were received from or estimated for 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City. In 1998 and 1999, CDC compiled abortion data from 48 reporting areas. Alaska, California, New Hampshire, and Oklahoma did not report, and data for these states were not estimated. For 2000-2002, Oklahoma again reported these data, increasing the number of reporting areas to 49. A total of 854,122 legal induced abortions were reported to CDC for 2002 from 49 reporting areas, representing a 0.1% increase from the 853,485 legal induced abortions reported by the same 49 reporting areas for 2001. The abortion ratio, defined as the number of abortions per 1,000 live births, was 246 in 2002, the same as reported for 2001. The abortion rate was 16 per 1,000 women aged 15-44 years for 2002, the same as for 2001. For the same 48 reporting areas, the abortion rate remained relatively constant during 1997-2002. The highest percentages of reported abortions were for women who were unmarried (82%), white (55%), and aged <25 years (51%). Of all abortions for which gestational age was reported, 60% were performed at < or =8 weeks' gestation and 88% at <13 weeks. From 1992 (when detailed data regarding early abortions were first collected) through 2002, steady increases have occurred in the percentage of abortions performed at < or =6 weeks' gestation. A limited number of abortions was obtained at >15 weeks' gestation, including 4.1% at 16-20 weeks and 1.4% at > or =21 weeks. A total of 35 reporting areas submitted data stating that they performed and enumerated medical (nonsurgical) procedures, accounting for 5.2% of all known reported procedures from the 45 areas with adequate reporting on type of procedure. During 1990-1997, the number of legal induced abortions gradually declined. When the same 48 reporting areas were compared, the number of abortions decreased during 1996-2001, then slightly increased in 2002. In 2000 and 2001, even with one additional reporting state, the number of abortions declined slightly, with a minimal increase in 2002. Abortion surveillance in the United States continues to provide the data necessary for examining trends in numbers and characteristics of women who obtain legal induced abortions and to increase understanding of this pregnancy outcome. Policymakers and program planners use these data to improve the health and well-being of women and infants.

Abortion surveillance--United States, 1999.

PubMed

Elam-Evans, Laurie D; Strauss, Lilo T; Herndon, Joy; Parker, Wilda Y; Whitehead, Sara; Berg, Cynthia J

2002-11-29

CDC began abortion surveillance in 1969 to document the number and characteristics of women obtaining legal induced abortions and to monitor unintended pregnancy. This report summarizes and describes data reported to CDC regarding legal induced abortions obtained in the United States in 1999. For each year since 1969, CDC has compiled abortion data by state or area of occurrence. From 1973 through 1997, data were received from or estimated for 52 reporting areas in the United States: 50 states, the District of Columbia, and New York City. Beginning in 1998, CDC compiled abortion data from 48 reporting areas. Alaska, California, New Hampshire, and Oklahoma did not report, and data for these areas were not estimated. The availability of data regarding the characteristics of women who obtained an abortion in 1999 varied by state and by the number of states reporting each characteristic. The total number of legal induced abortions is reported by state of residence and also by state of occurrence for most areas; characteristics of women obtaining abortions in 1999 are reported by state of occurrence. A total of 861,789 legal induced abortions were reported to CDC for 1999, representing a 2.5% decrease from the 884,273 legal induced abortions reported by the same 48 reporting areas for 1998. The abortion ratio, defined as the number of abortions per 1,000 live births, was 256 in 1999, compared with 264 reported for 1998; the abortion rate for these 48 reporting areas was 17 per 1,000 women aged 15-44 years for 1999, the same as in 1997 and 1998. The highest percentages of abortions were reported for women aged < 25 years, women who were white, and unmarried women; slightly more than half were obtaining an abortion for the first time. Fifty-eight percent of all abortions for which gestational age was reported were performed at < or = 8 weeks of gestation, and 88% were performed before 13 weeks. From 1992 (when these data were first collected) through 1999, increases have occurred in the percentage of abortions performed at < or = 6 weeks of gestation. Few abortions were provided after 15 weeks of gestation; 4.3% were obtained at 16-20 weeks and 1.5% were obtained at > or = 21 weeks. A total of 27 reporting areas submitted data stating that they performed medical (nonsurgical) procedures (two of these areas categorized medical abortions with "other" procedures), making up < 1.0% of all procedures reported from all reporting areas. In 1998 (for which data have not been published previously and the most recent year for which such data are available), nine women died as a result of complications from known legal induced abortion; no deaths were associated with known illegal abortion. From 1990 through 1997, the number of legal induced abortions gradually declined. In 1998 and in 1999, the number of abortions continued to decrease when comparing the same 48 reporting areas. In 1998, as in previous years, deaths related to legal induced abortions occurred rarely. Abortion surveillance in the United States should continue so that trends and characteristics of women who obtain legal induced abortions can be examined and efforts to prevent unintended pregnancy can be enhanced.

Abdominal aortic aneurysm: An update

PubMed

Chuen, Jason; Theivendran, Mayo

2018-05-01

Abdominal aortic aneurysm (AAA) remains one of the hallmark pathologies in vascular surgery and an area of intense research interest. Treatment options have expanded in recent years to increase the range of morphology suitable for endovascular aneurysm repair (EVAR), and with potential implications on treatment thresholds. This article is the first of two that will outline current treatment options for AAA, including areas of controversy and research in AAA disease, to inform the development of Australasian clinical guidelines and health policy. Medical therapy options remain limited and no aneurysm-specific pharmacotherapy is currently available. Recent years have witnessed a significant shift in AAA surgery from open repair to EVAR and expansion of EVAR techniques. General management of cardiovascular risk factors remains key to reducing all-cause mortality for patients with AAA.

Advanced Oxidation Protein Products and Carbonylated Proteins as Biomarkers of Oxidative Stress in Selected Atherosclerosis-Mediated Diseases.

PubMed

Gryszczyńska, Bogna; Formanowicz, Dorota; Budzyń, Magdalena; Wanic-Kossowska, Maria; Pawliczak, Elżbieta; Formanowicz, Piotr; Majewski, Wacław; Strzyżewski, Krzysztof Wojciech; Kasprzak, Magdalena P; Iskra, Maria

2017-01-01

The main question of this study was to evaluate the intensity of oxidative protein modification shown as advanced oxidation protein products (AOPP) and carbonylated proteins, expressed as protein carbonyl content (C=O) in abdominal aortic aneurysms (AAA), aortoiliac occlusive disease (AIOD), and chronic kidney disease (CKD). The study was carried out in a group of 35 AAA patients and 13 AIOD patients. However, CKD patients were divided into two groups: predialysis (PRE) included 50 patients or hemodialysis (HD) consisted of 34 patients. AOPP and C=O were measured using colorimetric assay kit, while C-reactive protein concentration was measured by high-sensitivity assay (hsCRP). The concentration of AOPP in both AAA and AIOD groups was higher than in PRE and HD groups according to descending order: AAA~AIOD > HD > PRE. The content of C=O was higher in the PRE group in comparison to AIOD and AAA according to the descending order: PRE~HD > AAA~AIOD. AAA, AIOD, and CKD-related atherosclerosis (PRE and HD) contribute to the changes in the formation of AOPP and C=O. They may promote modification of proteins in a different way, probably due to the various factors that influence oxidative stress here.

CFD modelling of abdominal aortic aneurysm on hemodynamic loads using a realistic geometry with CT.

PubMed

Soudah, Eduardo; Ng, E Y K; Loong, T H; Bordone, Maurizio; Pua, Uei; Narayanan, Sriram

2013-01-01

The objective of this study is to find a correlation between the abdominal aortic aneurysm (AAA) geometric parameters, wall stress shear (WSS), abdominal flow patterns, intraluminal thrombus (ILT), and AAA arterial wall rupture using computational fluid dynamics (CFD). Real AAA 3D models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 5 patients. Based on 3D AAA models, high quality volume meshes were created using an optimal tetrahedral aspect ratio for the whole domain. In order to quantify the WSS and the recirculation inside the AAA, a 3D CFD using finite elements analysis was used. The CFD computation was performed assuming that the arterial wall is rigid and the blood is considered a homogeneous Newtonian fluid with a density of 1050 kg/m(3) and a kinematic viscosity of 4 × 10(-3) Pa·s. Parallelization procedures were used in order to increase the performance of the CFD calculations. A relation between AAA geometric parameters (asymmetry index ( β ), saccular index ( γ ), deformation diameter ratio ( χ ), and tortuosity index ( ε )) and hemodynamic loads was observed, and it could be used as a potential predictor of AAA arterial wall rupture and potential ILT formation.

Porphyromonas gingivalis Participates in Pathogenesis of Human Abdominal Aortic Aneurysm by Neutrophil Activation. Proof of Concept in Rats

PubMed Central

Delbosc, Sandrine; Alsac, Jean-Marc; Journe, Clement; Louedec, Liliane; Castier, Yves; Bonnaure-Mallet, Martine; Ruimy, Raymond; Rossignol, Patrick; Bouchard, Philippe; Michel, Jean-Baptiste; Meilhac, Olivier

2011-01-01

Background Abdominal Aortic Aneurysms (AAAs) represent a particular form of atherothrombosis where neutrophil proteolytic activity plays a major role. We postulated that neutrophil recruitment and activation participating in AAA growth may originate in part from repeated episodes of periodontal bacteremia. Methods and Findings Our results show that neutrophil activation in human AAA was associated with Neutrophil Extracellular Trap (NET) formation in the IntraLuminal Thrombus, leading to the release of cell-free DNA. Human AAA samples were shown to contain bacterial DNA with high frequency (11/16), and in particular that of Porphyromonas gingivalis (Pg), the most prevalent pathogen involved in chronic periodontitis, a common form of periodontal disease. Both DNA reflecting the presence of NETs and antibodies to Pg were found to be increased in plasma of patients with AAA. Using a rat model of AAA, we demonstrated that repeated injection of Pg fostered aneurysm development, associated with pathological characteristics similar to those observed in humans, such as the persistence of a neutrophil-rich luminal thrombus, not observed in saline-injected rats in which a healing process was observed. Conclusions Thus, the control of periodontal disease may represent a therapeutic target to limit human AAA progression. PMID:21533243

Meta-Analysis of Genome-Wide Association Studies for Abdominal Aortic Aneurysm Identifies Four New Disease-Specific Risk Loci

PubMed Central

Tromp, Gerard; Kuivaniemi, Helena; Gretarsdottir, Solveig; Baas, Annette F.; Giusti, Betti; Strauss, Ewa; van‘t Hof, Femke N.G.; Webb, Thomas R.; Erdman, Robert; Ritchie, Marylyn D.; Elmore, James R.; Verma, Anurag; Pendergrass, Sarah; Kullo, Iftikhar J.; Ye, Zi; Peissig, Peggy L.; Gottesman, Omri; Verma, Shefali S.; Malinowski, Jennifer; Rasmussen-Torvik, Laura J.; Borthwick, Kenneth M.; Smelser, Diane T.; Crosslin, David R.; de Andrade, Mariza; Ryer, Evan J.; McCarty, Catherine A.; Böttinger, Erwin P.; Pacheco, Jennifer A.; Crawford, Dana C.; Carrell, David S.; Gerhard, Glenn S.; Franklin, David P.; Carey, David J.; Phillips, Victoria L.; Williams, Michael J.A.; Wei, Wenhua; Blair, Ross; Hill, Andrew A.; Vasudevan, Thodor M.; Lewis, David R.; Thomson, Ian A.; Krysa, Jo; Hill, Geraldine B.; Roake, Justin; Merriman, Tony R.; Oszkinis, Grzegorz; Galora, Silvia; Saracini, Claudia; Abbate, Rosanna; Pulli, Raffaele; Pratesi, Carlo; Saratzis, Athanasios; Verissimo, Ana R.; Bumpstead, Suzannah; Badger, Stephen A.; Clough, Rachel E.; Cockerill, Gillian; Hafez, Hany; Scott, D. Julian A.; Futers, T. Simon; Romaine, Simon P.R.; Bridge, Katherine; Griffin, Kathryn J.; Bailey, Marc A.; Smith, Alberto; Thompson, Matthew M.; van Bockxmeer, Frank M.; Matthiasson, Stefan E.; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Blankensteijn, Jan D.; Teijink, Joep A.W.; Wijmenga, Cisca; de Graaf, Jacqueline; Kiemeney, Lambertus A.; Lindholt, Jes S.; Hughes, Anne; Bradley, Declan T.; Stirrups, Kathleen; Golledge, Jonathan; Norman, Paul E.; Powell, Janet T.; Humphries, Steve E.; Hamby, Stephen E.; Goodall, Alison H.; Nelson, Christopher P.; Sakalihasan, Natzi; Courtois, Audrey; Ferrell, Robert E.; Eriksson, Per; Folkersen, Lasse; Franco-Cereceda, Anders; Eicher, John D.; Johnson, Andrew D.; Betsholtz, Christer; Ruusalepp, Arno; Franzén, Oscar; Schadt, Eric E.; Björkegren, Johan L.M.; Lipovich, Leonard; Drolet, Anne M.; Verhoeven, Eric L.; Zeebregts, Clark J.; Geelkerken, Robert H.; van Sambeek, Marc R.; van Sterkenburg, Steven M.; de Vries, Jean-Paul; Stefansson, Kari; Thompson, John R.; de Bakker, Paul I.W.; Deloukas, Panos; Sayers, Robert D.; Harrison, Seamus C.; van Rij, Andre M.; Samani, Nilesh J.

2017-01-01

Rationale: Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA. Objective: To identify additional AAA risk loci using data from all available genome-wide association studies. Methods and Results: Through a meta-analysis of 6 genome-wide association study data sets and a validation study totaling 10 204 cases and 107 766 controls, we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches, we observed no new associations between the lead AAA single nucleotide polymorphisms and coronary artery disease, blood pressure, lipids, or diabetes mellitus. Network analyses identified ERG, IL6R, and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9. Conclusions: The 4 new risk loci for AAA seem to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease. PMID:27899403

A pull-back algorithm to determine the unloaded vascular geometry in anisotropic hyperelastic AAA passive mechanics.

PubMed

Riveros, Fabián; Chandra, Santanu; Finol, Ender A; Gasser, T Christian; Rodriguez, Jose F

2013-04-01

Biomechanical studies on abdominal aortic aneurysms (AAA) seek to provide for better decision criteria to undergo surgical intervention for AAA repair. More accurate results can be obtained by using appropriate material models for the tissues along with accurate geometric models and more realistic boundary conditions for the lesion. However, patient-specific AAA models are generated from gated medical images in which the artery is under pressure. Therefore, identification of the AAA zero pressure geometry would allow for a more realistic estimate of the aneurysmal wall mechanics. This study proposes a novel iterative algorithm to find the zero pressure geometry of patient-specific AAA models. The methodology allows considering the anisotropic hyperelastic behavior of the aortic wall, its thickness and accounts for the presence of the intraluminal thrombus. Results on 12 patient-specific AAA geometric models indicate that the procedure is computational tractable and efficient, and preserves the global volume of the model. In addition, a comparison of the peak wall stress computed with the zero pressure and CT-based geometries during systole indicates that computations using CT-based geometric models underestimate the peak wall stress by 59 ± 64 and 47 ± 64 kPa for the isotropic and anisotropic material models of the arterial wall, respectively.

Beneficial Effects of Pre-operative Exercise Therapy in Patients with an Abdominal Aortic Aneurysm: A Systematic Review.

PubMed

Pouwels, S; Willigendael, E M; van Sambeek, M R H M; Nienhuijs, S W; Cuypers, P W M; Teijink, J A W

2015-01-01

The impact of post-operative complications in abdominal aortic aneurysm (AAA) surgery is substantial, and increases with age and concomitant co-morbidities. This systematic review focuses on the possible effects of pre-operative exercise therapy (PET) in patients with AAA on post-operative complications,aerobic capacity, physical fitness, and recovery. A systematic search on PET prior to AAA surgery was conducted. The methodological quality of the included studies was rated using the Physiotherapy Evidence Database scale. The agreement between the reviewers was assessed with Cohen's kappa. Five studies were included, with a methodological quality ranging from moderate to good. Cohen's kappa was 0.79. Three studies focused on patients with an AAA (without indication for surgical repair) with physical fitness as the outcome measure. One study focused on PET in patients awaiting AAA surgery and one study focused on the effects of PET on post-operative complications, length of stay, and recovery. PET has beneficial effects on various physical fitness variables of patients with an AAA. Whether this leads to less complications or faster recovery remains unclear. In view of the large impact of post-operative complications, it is valuable to explore the possible benefits of a PET program in AAA surgery.

Hyperhomocysteinaemia is an independent risk factor of abdominal aortic aneurysm in a Chinese Han population

PubMed Central

Liu, Jie; Wei Zuo, Shang; Li, Yue; Jia, Xin; Jia, Sen Hao; Zhang, Tao; Xiang Song, Yu; Qi Wei, Ying; Xiong, Jiang; Hua Hu, Yong; Guo, Wei

2016-01-01

The associations between hyperhomocysteinaemia (HHcy), methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, and abdominal aortic aneurysm (AAA) remain controversial, with only few studies focused on these associations within the Chinese population. We performed subgroup and interaction analyses in a Chinese Han population to investigate these associations. In all, 155 AAA patients and 310 control subjects were evaluated for serum total homocysteine levels and MTHFR C677T polymorphisms. Multiple logistic regression models were used to evaluate the aforementioned associations. Interaction and stratified analyses were conducted according to age, sex, smoking status, drinking status, and chronic disease histories. The multiple logistic analyses showed a significant association between HHcy and AAA but no significant association between MTHFR C677T polymorphism and AAA. The interaction analysis showed that age and peripheral arterial disease played an interactive role in the association between HHcy and AAA, while drinking status played an interactive role in the association between MTHFR C677T polymorphism and AAA. In conclusion, HHcy is an independent risk factor of AAA in a Chinese Han population, especially in the elderly and peripheral arterial disease subgroups. Longitudinal studies and clinical trials aimed to reduce homocysteine levels are warranted to assess the causal nature of these relationships PMID:26865327

48 CFR 302.7000 - Common HHSAR acronyms and abbreviations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... acronyms and abbreviations. (a) The HHSAR cites numerous acquisition-related and organizational acronyms...-3(b)(3). CDC Centers for Disease Control and Prevention 301.270(b). CFR Code of Federal Regulations....1300(c). PSC Program Support Center (in OS) 301.270(b). R&D research and development 301.607-72(b). RFI...

The root application of a purified leonardite humic acid modifies the transcriptional regulation of the main physiological root responses to Fe deficiency in Fe-sufficient cucumber plants.

PubMed

Aguirre, Elena; Elena, Aguirre; Leménager, Diane; Diane, Leménager; Bacaicoa, Eva; Eva, Bacaicoa; Fuentes, Marta; Marta, Fuentes; Baigorri, Roberto; Roberto, Baigorri; Zamarreño, Angel Ma; García-Mina, José Ma

2009-03-01

The aim of this study is to investigate the effect of a well-characterized purified humic acid (non-measurable concentrations of the main plant hormones were detected) on the transcriptional regulation of the principal molecular agents involved in iron assimilation. To this end, non-deficient cucumber plants were treated with different concentrations of a purified humic acid (PHA) (2, 5, 100 and 250 mg of organic carbonL(-1)) and harvested 4, 24, 48, 76 and 92 h from the onset of the treatment. At harvest times, the mRNA transcript accumulation of CsFRO1 encoding for Fe(III) chelate-reductase (EC 1.16.1.7); CsHa1 and CsHa2 encoding for plasma membrane H+-ATPase (EC 3.6.3.6); and CsIRT1 encoding for Fe(II) high-affinity transporter, was quantified by real-time RT-PCR. Meanwhile, the respective enzyme activity of the Fe(III) chelate-reductase and plasma membrane H+-ATPase was also investigated. The results obtained indicated that PHA root treatments affected the regulation of the expression of the studied genes, but this effect was transient and differed (up-regulation or down-regulation) depending on the genes studied. Thus, principally the higher doses of PHA caused a transient increase in the expression of the CsHa2 isoform for 24 and 48 h whereas the CsHa1 isoform was unaffected or down-regulated. These effects were accompanied by an increase in the plasma membrane H+-ATPase activity for 4, 48 and 96 h. Likewise, PHA root treatments (principally the higher doses) up-regulated CsFRO1 and CsIRT1 expression for 48 and 72 h; whereas these genes were down-regulated by PHA for 96 h. These effects were associated with an increase in the Fe(III) chelate-reductase activity for 72 h. These effects were not associated with a significant decrease in the Fe root or leaf concentrations, although an eventual effect on the Fe root assimilation pattern cannot be ruled out. These results stress the close relationships between the effects of humic substances on plant development and iron nutrition. However, further studies are needed in order to elucidate if these effects at molecular level are caused by mechanisms involving hormone-like actions and/or nutritional factors.

Diabetes mellitus increases the risk of ruptured abdominal aortic aneurysms.

PubMed

Wierzba, Waldemar; Sliwczynski, Andrzej; Pinkas, Jaroslaw; Jawien, Arkadiusz; Karnafel, Waldemar

2017-09-01

The publication is a polemical response to reports that present data that diabetes reduces the risk of rupture of abdominal aortic aneurysm (AAA). The study analyzed all cases of developing AAA in patients with and without diabetes in 2012 in Poland. Data for the analysis were obtained with a unique and complete resources of the National Health Fund (NFZ) and population data from the Central Statistical Office (GUS). In Poland during 2012 2,227,453 patients with diabetes were treated, 975,364 males and 1,252,089 females. The incidence of AAA without rupture in patients without diabetes calculated per 100,000 of the non-diabetes general population was 25.0 +/- 9.0 in males and 5.6 +/- 2.3 in females. The incidence of ruptured AAA in the general population without diabetes was 3.6 +/- 0.9 in males, and 0.6 +/- 0.3 in females calculated per 100,000 of inhabitants without diabetes. The incidence of AAA without rupture in patients with diabetes was 184.897 +/- 70.653 in males and 35.364 +/- 24.925 in females calculated per 100,000 of patients diagnosed with diabetes. The incidence of ruptured AAA in patients with diabetes was 21.090 +/- 6.050 in males and 5.170 +/- 3.053 in females calculated per 100,000 of patients diagnosed with diabetes. The incidence rate for ruptured AAA in 2012 in Poland is statistically higher both in females and males in the population with diabetes. The incidence rate for AAA without rupture in 2012 in Poland is statistically higher in patients diagnosed with diabetes.

Total laparorobotic repair of abdominal aortic aneurysm with sac exclusion obliteration and aortobifemoral bypass.

PubMed

Wu, Timothy; Prema, Jateen; Zagaja, Gregory; Shalhav, Arieh; Bassiouny, Hisham S

2009-01-01

A 65-year-old man with coronary artery disease, hypertension, and peripheral vascular disease was found to have an asymptomatic abdominal aortic aneurysm (AAA) of 5.5 cm on surveillance for his peripheral vascular disease. Cardiac stress testing demonstrated no evidence of myocardial ischemia, and he opted to undergo open repair of his aneurysm. Laparorobotic repair of the infrarenal AAA using the da Vinci robotic system was performed with an aortobifemoral bypass. We describe a novel technique for AAA exclusion using a cerclage method, which greatly facilitates repair of infrarenal AAAs using laparorobotic techniques. Laparorobotic repair of infrarenal AAA can be greatly facilitated by AAA sac exclusion and obliteration without the need to ligate all lumbar arteries or to open the aneurysm. This virtually avoids blood loss from the sac and minimizes the possibility for open conversion as a result of poor visualization. Minimally invasive aortic intervention for aneurysmal disease using laparascopic methods has been reported in the literature. Problems associated with this technique include a prolonged learning curve and difficulty completing intracorporeal anastomoses. Robotic surgery provides an advantage over laparoscopic surgery in its ability to provide greater degrees of freedom in a relatively small field of view along with superior high-definition, three-dimensional visualization. To date, there have been no known reports of using robotic surgery in the United States as a sole method for repair of AAA. We report our technique of combining robotic surgery with a novel procedure for sac exclusion and obliteration to successfully repair AAA without the need for opening the aneurysm sac and endoaneurysmorrhaphy.

Functional characterization of T cells in abdominal aortic aneurysms

PubMed Central

Forester, Nerys D; Cruickshank, Sheena M; Scott, D Julian A; Carding, Simon R

2005-01-01

Abdominal aortic aneurysms (AAA) exhibit features of a chronic inflammatory disorder. The functional attributes of the T cells in AAA tissue are unclear, with little quantitative or functional data. Using a novel, non-enzymatic method to isolate viable cells from AAA tissue, functional properties of AAA T cells were investigated for the first time. Composition and phenotype of AAA T cells was determined by flow cytometry and verified by immunohistochemistry. Tissue mononuclear cells (MNCs) were cultured in the presence of T-cell mitogens, and cell cycle analysis and cytokine production assessed. Typical cell yield was 4·5 × 106 cells per gram of AAA tissue. The majority (58·1 ± 5·3%) of haematopoietic (CD45+) cells recovered were CD3+ T cells, B cells comprised 41·1 ± 5·7%, natural killer cells 7·3 ± 2·5%, and macrophages 2%. Freshly isolated T cells were in resting (G1) state, with 25% expressing the activation-associated cell surface antigens major histocompatibility complex II and CD25. When stimulated in vitro, a significant proportion entered S and G2 phase of the cell cycle, up-regulated CD25, and secreted tumour necrosis factor-α, interferon-γ, interleukin (IL)-5 and IL-6. Despite patient differences, the composition of the AAA inflammatory infiltrate was remarkably consistent, and when re-stimulated ex-vivo T cells produced a stereotypical cytokine response, consistent with the hypothesis that AAA T cells can promote tissue inflammation by secretion of proinflammatory cytokines, and in addition provide signals for B-cell help. PMID:15885133

Atmospheric Pressure and Abdominal Aortic Aneurysm Rupture: Results From a Time Series Analysis and Case-Crossover Study.

PubMed

Penning de Vries, Bas B L; Kolkert, Joé L P; Meerwaldt, Robbert; Groenwold, Rolf H H

2017-10-01

Associations between atmospheric pressure and abdominal aortic aneurysm (AAA) rupture risk have been reported, but empirical evidence is inconclusive and largely derived from studies that did not account for possible nonlinearity, seasonality, and confounding by temperature. Associations between atmospheric pressure and AAA rupture risk were investigated using local meteorological data and a case series of 358 patients admitted to hospital for ruptured AAA during the study period, January 2002 to December 2012. Two analyses were performed-a time series analysis and a case-crossover study. Results from the 2 analyses were similar; neither the time series analysis nor the case-crossover study showed a significant association between atmospheric pressure ( P = .627 and P = .625, respectively, for mean daily atmospheric pressure) or atmospheric pressure variation ( P = .464 and P = .816, respectively, for 24-hour change in mean daily atmospheric pressure) and AAA rupture risk. This study failed to support claims that atmospheric pressure causally affects AAA rupture risk. In interpreting our results, one should be aware that the range of atmospheric pressure observed in this study is not representative of the atmospheric pressure to which patients with AAA may be exposed, for example, during air travel or travel to high altitudes in the mountains. Making firm claims regarding these conditions in relation to AAA rupture risk is difficult at best. Furthermore, despite the fact that we used one of the largest case series to date to investigate the effect of atmospheric pressure on AAA rupture risk, it is possible that this study is simply too small to demonstrate a causal link.

Animal-assisted activity and emotional status of patients with Alzheimer's disease in day care.

PubMed

Mossello, Enrico; Ridolfi, Alessandro; Mello, Anna Maria; Lorenzini, Giulia; Mugnai, Francesca; Piccini, Carolina; Barone, Domenico; Peruzzi, Anna; Masotti, Giulio; Marchionni, Niccolò

2011-08-01

Preliminary studies suggest beneficial effects of animal-assisted activities (AAA) on behavioral and psychological symptoms of dementia (BPSD), but data are inconsistent. This study aimed to assess the effect of AAA with dogs on cognition, BPSD, emotional status and motor activity in severe Alzheimer's disease (AD). Ten patients attending an Alzheimer Day Care Center (ADCC) participated in a repeated measures study, which included: two weeks' pre-intervention, three weeks' control activity with plush dogs (CA), and three weeks' AAA. Cognitive function (Severe Impairment Battery), mood (Cornell Scale for Depression in Dementia; CSDD), BPSD (Neuropsychiatric Inventory; NPI) and agitation (Cohen-Mansfield Agitation Inventory; CMAI) were assessed at baseline and after each period. Observed Emotion Rating Scale (OERS) for emotional status, Agitated Behavior Mapping Instrument (ABMI) and a checklist for motor activity were completed across the study periods, both during intervention sessions and after three hours. Cognition and NPI were unchanged across the study. Declines in the CMAI and CSDD scores after AAA were not significant, while the NPI anxiety item score decreased in comparison with CA (CA 3.1±2.3, AAA 1.5±2.7, p = 0.04). OERS "sadness" decreased (p = 0.002), while "pleasure" (p = 0.016) and "general alertness" (p = 0.003) increased during AAA compared with CA sessions, and observed sadness remained lower after three hours (p = 0.002). Motor activity increased significantly during AAA. In this sample of severe AD patients in ADCC, AAA was associated with a decrease in anxiety and sadness and an increase in positive emotions and motor activity in comparison with a control activity.

Characterization of the binding specificity of Anguilla anguilla agglutinin (AAA) in comparison to Ulex europaeus agglutinin I (UEA-I).

PubMed

Baldus, S E; Thiele, J; Park, Y O; Hanisch, F G; Bara, J; Fischer, R

1996-08-01

Using immunochemical and immunohistochemical methods, the binding site of Anguilla anguilla agglutinin (AAA) was characterized and compared with the related fucose-specific lectin from Ulex europaeus (UEA-I). In solid-phase enzyme-linked immunoassays, the two lectins recognized Fuc alpha 1-2Gal beta-HSA. AAA additionally cross-reacted with neoglycolipids bearing lacto-N-fucopentaose (LNFP) I [H type 1] and II [Le(a)] and lactodifucotetraose (LDFT) as glycan moieties. UEA-I, on the other hand, bound to a LDFT-derived neoglycolipid but not to the other neoglycolipids tested. Binding of AAA to gastric mucin was competitively neutralized by Le(a)-specific monoclonal antibodies. UEA-I binding, on the other hand, was reduced after co-incubation with H type 2- and Le(y)-specific monoclonal antibodies. According to our results, AAA reacts with fucosylated type 1 chain antigens, whereas UEA-I binds only to the alpha 1-2-fucosylated LDFT-derived neoglycolipid. In immunohistochemical studies, the reactivity of AAA and UEA-I in normal pyloric mucosa from individuals with known Lewis and secretor status was analysed. AAA showed a broad reaction in the superficial pyloric mucosa from secretors and non-secretors, but AAA reactivity was more pronounced in Le(a+b-) individuals. On the other hand, UEA-I stained the superficial pyloric mucosa only from secretor individuals. A staining of deep mucous glands by the lectins was found in all specimens. Both reacted with most human carcinomas of different origin. Slight differences in their binding pattern were observed and may be explained by the different fine-specificities of the lectins.

Quantitative expression and localization of cysteine and aspartic proteases in human abdominal aortic aneurysms

PubMed Central

Lohoefer, Fabian; Reeps, Christian; Lipp, Christina; Rudelius, Martina; Haertl, Felix; Matevossian, Edouard; Zernecke, Alma; Eckstein, Hans-Henning; Pelisek, Jaroslav

2014-01-01

Cysteine and aspartic proteases possess high elastolytic activity and might contribute to the degradation of the abdominal aortic aneurysm (AAA) wall. The aim of this study was to analyze, in detail, the proteases (cathepsins B, D, K, L and S, and inhibitor cystatin C) found in human AAA and healthy aortic tissue samples. The vessel walls from AAA patients (n=36) and nonaneurysmal aortae (n=10) were retrieved using conventional surgical repair and autopsy methods. Serum samples from the same AAA patients and 10 healthy volunteers were also collected. Quantitative expression analyses were performed at the mRNA level using real-time reverse transcriptase-PCR (RT–PCR). Furthermore, analyses at the protein level included western blot and immunoprecipitation analyses. Cellular sources of cysteine/aspartic proteases and cystatin C were identified by immunohistochemistry (IHC). All cysteine/aspartic proteases and cystatin C were detected in the AAA and control samples. Using quantitative RT–PCR, a significant increase in expression was observed for cathepsins B (P=0.021) and L (P=0.018), compared with the controls. Cathepsin B and cystatin C were also detected in the serum of AAA patients. Using IHC, smooth muscle cells (SMCs) and macrophages were positive for all of the tested cathepsins, as well as cystatin C; in addition, the lymphocytes were mainly positive for cathepsin B, followed by cathepsins D and S. All cysteine/aspartic proteases analyzed in our study were detected in the AAA and healthy aorta. The highest expression was found in macrophages and SMCs. Consequently, cysteine/aspartic proteases might play a substantial role in AAA. PMID:24833013

Leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent regeneration.

PubMed

Takayama, Kazuya; Muto, Akihiko; Kikuchi, Yutaka

2018-05-29

In animal regeneration, control of position-dependent cell proliferation is crucial for the complete restoration of patterned appendages in terms of both, shape and size. However, detailed mechanisms of this process are largely unknown. In this study, we identified leucine/glutamine and v-ATPase/lysosomal acidification, via mechanistic target of rapamycin complex 1 (mTORC1) activation, as effectors of amputation plane-dependent zebrafish caudal fin regeneration. mTORC1 activation, which functions in cell proliferation, was regulated by lysosomal acidification possibly via v-ATPase activity at 3 h post amputation (hpa). Inhibition of lysosomal acidification resulted in reduced growth factor-related gene expression and suppression of blastema formation at 24 and 48 hpa, respectively. Along the proximal-distal axis, position-dependent lysosomal acidification and mTORC1 activation were observed from 3 hpa. We also report that Slc7a5 (L-type amino acid transporter), whose gene expression is position-dependent, is necessary for mTORC1 activation upstream of lysosomal acidification during fin regeneration. Furthermore, treatment with leucine and glutamine, for both proximal and distal fin stumps, led to an up-regulation in cell proliferation via mTORC1 activation, indicating that leucine/glutamine signaling possesses the ability to change the position-dependent regeneration. Our findings reveal that leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent zebrafish fin regeneration.

77 FR 13608 - Proposed Data Collections Submitted for Public Comment and Recommendations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-07

... Against AIDS (AAA) in 2009, a 5-year, multifaceted communication campaign consisting of several campaigns targeting various high-risk populations. The overall goals of AAA are to increase HIV/AIDS awareness and reduce HIV incidence in the United States. Each AAA campaign uses mass media and direct-to-consumer...

Advanced, Analytic, Automated (AAA) Measurement of Engagement during Learning

ERIC Educational Resources Information Center

D'Mello, Sidney; Dieterle, Ed; Duckworth, Angela

2017-01-01

It is generally acknowledged that engagement plays a critical role in learning. Unfortunately, the study of engagement has been stymied by a lack of valid and efficient measures. We introduce the advanced, analytic, and automated (AAA) approach to measure engagement at fine-grained temporal resolutions. The AAA measurement approach is grounded in…

Common iliac artery aneurysms in patients with abdominal aortic aneurysms.

PubMed

Armon, M P; Wenham, P W; Whitaker, S C; Gregson, R H; Hopkinson, B R

1998-03-01

To determine the incidence of common iliac artery (CIA) aneurysms in patients with abdominal aortic aneurysms (AAA) and to evaluate the relationship between AAA and CIA diameter. Spiral CT angiography was used to measure the maximum diameters of the abdominal aorta and the common iliac arteries of 215 patients with AAA. The median CIA diameter was 1.7 cm--significantly greater than the published mean of 1.25 (2 S.D. = 0.85-1.65) cm of an age-matched, non-vascular population. Thirty-four patients (16%) had unilateral and 26 patients (12%) bilateral CIA aneurysms > or = 2.4 cm diameter. Eight-six vessels (20%) were affected. Right CIA diameters were wider than left CIA diameters (p < 0.0001, Wilcoxon matched-pairs signed rank test). The correlation between AAA size and CIA diameter was weak. The AAA population has abnormally dilated common iliac arteries. In this population, common iliac artery aneurysms should be defined as those greater than 2.4 cm diameter. 20% of CIAs in patients with AAA are aneurysmal according to this definition.

m-AAA and i-AAA complexes coordinate to regulate OMA1, the stress-activated supervisor of mitochondrial dynamics.

PubMed

Consolato, Francesco; Maltecca, Francesca; Tulli, Susanna; Sambri, Irene; Casari, Giorgio

2018-04-09

The proteolytic processing of dynamin-like GTPase OPA1, mediated by the activity of both YME1L1 [intermembrane (i)-AAA protease complex] and OMA1, is a crucial step in the regulation of mitochondrial dynamics. OMA1 is a zinc metallopeptidase of the inner mitochondrial membrane that undergoes pre-activating proteolytic and auto-proteolytic cleavage after mitochondrial import. Here, we identify AFG3L2 [matrix (m) - AAA complex] as the major protease mediating this event, which acts by maturing the 60 kDa pre-pro-OMA1 to the 40 kDa pro-OMA1 form by severing the N-terminal portion without recognizing a specific consensus sequence. Therefore, m - AAA and i - AAA complexes coordinately regulate OMA1 processing and turnover, and consequently control which OPA1 isoforms are present, thus adding new information on the molecular mechanisms of mitochondrial dynamics and neurodegenerative diseases affected by these phenomena.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

AAA (2010) CAPD clinical practice guidelines: need for an update.

PubMed

DeBonis, David A

2017-09-01

Review and critique of the clinical value of the AAA CAPD guidance document in light of criteria for credible and useful guidance documents, as discussed by Field and Lohr. A qualitative review of the of the AAA CAPD guidelines using a framework by Field and Lohr to assess their relative value in supporting the assessment and management of CAPD referrals. Relevant literature available through electronic search tools and published texts were used along with the AAA CAPD guidance document and the chapter by Field and Lohr. The AAA document does not meet many of the key requirements discussed by Field and Lohr. It does not reflect the current literature, fails to help clinicians understand for whom auditory processing testing and intervention would be most useful, includes contradictory suggestions which reduce clarity and appears to avoid conclusions that might cast the CAPD construct in a negative light. It also does not include input from diverse affected groups. All of these reduce the document's credibility. The AAA CAPD guidance document will need to be updated and re-conceptualised in order to provide meaningful guidance for clinicians.

Adipocytes and abdominal aortic aneurysm: Putative potential role of adipocytes in the process of AAA development.

PubMed

Kugo, Hirona; Moriyama, Tatsuya; Zaima, Nobuhiro

2018-01-15

Background Adipose tissue plays a role in the storage of excess energy as triglycerides (TGs). Excess fat accumulation causes various metabolic and cardiovascular diseases. It has been reported that ectopic fat deposition and excess TG accumulation in non-adipose tissue might be important predictors of cardiometabolic and vascular risk. For example, ectopic fat in perivascular tissue promotes atherosclerotic plaque formation in the arterial wall. Objective Recently, it has been reported that ectopic fat (adipocyte) in the vascular wall of an abdominal aortic aneurysm (AAA) is present in both human and experimental animal models. The pathological significance of adipocytes in the AAA wall has not been fully understood. In this review, we summarized the functions of adipocytes and discussed potential new drugs that target vascular adipocytes for AAA treatment. Result Previous studies suggest that adipocytes in vascular wall play an important role in the development of AAA. Conclusion Adipocytes in the vascular wall could be novel targets for the development of AAA therapeutic drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Epidemiology of abdominal aortic aneurysms in the Asian community.

PubMed

Spark, J I; Baker, J L; Vowden, P; Wilkinson, D

2001-03-01

Studies relating to the ethnic origin of patients with an abdominal aortic aneurysm (AAA) are few and are mainly concerned with the differences between black and white Americans. The purpose of this study was to determine whether the incidence of AAA among the Asian population of Bradford is different from that in the Caucasian population. A retrospective study of patients with an AAA was carried out between 1990 and 1997 using data collected by the Patient Administrative Service, personal databases of the vascular consultants and theatre records. Information about the ethnic composition of the population of Bradford was obtained from the 1991 national census. Demographic data, including ethnic origin and clinical details, were obtained from patient notes. Two hundred and thirty-three patients with an AAA were identified during the study interval. The Asian population comprised 14.0 per cent of the total population of Bradford. Twenty-eight AAAs would be expected per year. All of the aneurysms identified occurred in the Caucasian population and none in the Asian community. These early results suggest that AAA is rare among the Asian population.

Mouse Na+/K+-ATPase β1-subunit has a K+-dependent cell adhesion activity for β-GlcNAc-terminating glycans

PubMed Central

Kitamura, Noriaki; Ikekita, Masahiko; Sato, Takeshi; Akimoto, Yoshihiro; Hatanaka, Yasumaru; Kawakami, Hayato; Inomata, Mitsushi; Furukawa, Kiyoshi

2005-01-01

A 48-kDa β-N-acetylglucosamine (GlcNAc)-binding protein was isolated from mouse brain by GlcNAc-agarose column chromatography. The N-terminal amino acid residues showed the protein to be a mouse Na+/K+-ATPase β1-subunit. When the recombinant FLAG-β1-subunit expressed in Sf-9 cells was applied to a GlcNAc-agarose column, only the glycosylated 38- and 40-kDa proteins bound to the column. In the absence of KCl, little of the proteins bound to a GlcNAc-agarose column, but the 38- and 40-kDa proteins bound in the presence of KCl at concentrations above 1 mM. Immunohistochemical study showed that the β1-subunit and GlcNAc-terminating oligosaccharides are at the cell contact sites. Inclusion of anti-β1-subunit antibody or chitobiose in cell aggregation assays using mouse neural cells resulted in inhibition of cell aggregation. These results indicate that the Na+/K+-ATPase β1-subunit is a potassium-dependent lectin that binds to GlcNAc-terminating oligosaccharides: it may be involved in neural cell interactions. PMID:15705719

PASCAL/48 reference manual

NASA Technical Reports Server (NTRS)

Knight, J. C.; Hamm, R. W.

1984-01-01

PASCAL/48 is a programming language for the Intel MCS-48 series of microcomputers. In particular, it can be used with the Intel 8748. It is designed to allow the programmer to control most of the instructions being generated and the allocation of storage. The language can be used instead of ASSEMBLY language in most applications while allowing the user the necessary degree of control over hardware resources. Although it is called PASCAL/48, the language differs in many ways from PASCAL. The program structure and statements of the two languages are similar, but the expression mechanism and data types are different. The PASCAL/48 cross-compiler is written in PASCAL and runs on the CDC CYBER NOS system. It generates object code in Intel hexadecimal format that can be used to program the MCS-48 series of microcomputers. This reference manual defines the language, describes the predeclared procedures, lists error messages, illustrates use, and includes language syntax diagrams.

Prohibitin (PHB) roles in granulosa cell physiology

PubMed Central

Chowdhury, Indrajit; Thomas, Kelwyn; Thompson, Winston E.

2015-01-01

Ovarian granulosa cells (GC) play an important role in the growth and development of the follicle in the process known as folliculogenesis. In the present review, we focus on the recent developments in prohibitin (PHB) research in relation to GC physiological functions. PHB is a member of highly conserved eukaryotic protein family containing the repressor of estrogen activity (REA)/stomatin/prohibitin/flotillin/HflK/C (SPFH) domain [also known as the PHB domain] found in divergent species from prokaryotes to eukaryotes. PHB is ubiquitously expressed either in circulating free form or is present in multiple cellular compartments including mitochondria, nucleus and plasma membrane. In mitochondria, PHB is anchored to the mitochondrial inner membrane (IMM), and form complexes with the ATPases Associated with diverse cellular Activities (m-AAA) proteases. PHB continuously shuttles between the mitochondria, cytosol and nucleus. In the nucleus, PHB interacts with various transcription factors and modulate transcriptional activity directly or through interactions with chromatin remodeling proteins. Multiple functions have been attributed to the mitochondrial and nuclear prohibitin complexes such as cellular differentiation, anti-proliferation, morphogenesis and maintaining the functional integrity of the mitochondria. However, to date, the regulation of PHB expression patterns and GC physiological functions are not completely understood. PMID:26496733

TorsinA controls TAN line assembly and the retrograde flow of dorsal perinuclear actin cables during rearward nuclear movement

PubMed Central

Saunders, Cosmo A.; Harris, Nathan J.; Willey, Patrick T.; Woolums, Brian M.; Wang, Yuexia; McQuown, Alex J.; Schoenhofen, Amy; Dauer, William T.

2017-01-01

The nucleus is positioned toward the rear of most migratory cells. In fibroblasts and myoblasts polarizing for migration, retrograde actin flow moves the nucleus rearward, resulting in the orientation of the centrosome in the direction of migration. In this study, we report that the nuclear envelope–localized AAA+ (ATPase associated with various cellular activities) torsinA (TA) and its activator, the inner nuclear membrane protein lamina-associated polypeptide 1 (LAP1), are required for rearward nuclear movement during centrosome orientation in migrating fibroblasts. Both TA and LAP1 contributed to the assembly of transmembrane actin-associated nuclear (TAN) lines, which couple the nucleus to dorsal perinuclear actin cables undergoing retrograde flow. In addition, TA localized to TAN lines and was necessary for the proper mobility of EGFP-mini–nesprin-2G, a functional TAN line reporter construct, within the nuclear envelope. Furthermore, TA and LAP1 were indispensable for the retrograde flow of dorsal perinuclear actin cables, supporting the recently proposed function for the nucleus in spatially organizing actin flow and cytoplasmic polarity. Collectively, these results identify TA as a key regulator of actin-dependent rearward nuclear movement during centrosome orientation. PMID:28242745

Reptin drives tumour progression and resistance to chemotherapy in non-small cell lung cancer.

PubMed

Mikesch, Jan-Henrik; Schwammbach, Daniela; Hartmann, Wolfgang; Schmidt, Lars H; Schliemann, Christoph; Angenendt, Linus; Wiewrodt, Rainer; Marra, Alessandro; Thoennissen, Nils H; Wardelmann, Eva; Köhler, Gabriele; Lenz, Georg; Müller-Tidow, Carsten; Berdel, Wolfgang E; Arteaga, Maria-Francisca

2018-05-31

While targeted non-small cell lung cancer (NSCLC) therapies improved outcome of defined disease subtypes, prognosis of most of the patients remains poor. We found the AAA+ ATPase Reptin to be highly expressed in the vast majority of 278 NSCLC tumour samples. Thus, the objective of the study was to assess the role of Reptin in NSCLC.Survival analyses of 1,145 NSCLC patients revealed that high RNA expression levels of Reptin are associated with adverse outcome. Knock down of Reptin in human NSCLC cells impaired growth ex vivo and eliminated engraftment in a xenograft model. We uncovered direct interaction of Reptin with histone deacetylase 1 (HDAC1), as the critical mechanism driving NSCLC tumour progression. Pharmacological disruption of Reptin/HDAC1 complex resulted in substantial decrease of NSCLC cell proliferation and induced significant sensitization to cisplatin.In conclusion, our results identify Reptin as a novel independent prognostic factor and as a key regulator mediating proliferation and clonal growth of human NSCLC cells ex vivo and in vivo We unveil a Reptin/HDAC1 protein complex whose pharmacological disruption sensitizes NSCLC cells to cisplatin, suggesting this approach for application in clinical trials. Copyright ©ERS 2018.

[Ultrasound screening of abdominal aortic aneurysm: Lessons from Vesale 2013].

PubMed

Laroche, J P; Becker, F; Baud, J M; Miserey, G; Jaussent, A; Picot, M C; Bura-Rivière, A; Quéré, I

2015-12-01

Although aneurysm of the abdominal infra-renal aorta (AAA) meets criteria warranting B mode ultrasound screening, the advantages of mass screening versus selective targeted opportunistic screening remain a subject of debate. In France, the French Society of Vascular Medicine (SFMV) and the Health Authority (HAS) published recommendations for targeted opportunistic screening in 2006 and 2013 respectively. The SFMV held a mainstream communication day on November 21, 2013 in France involving participants from metropolitan France and overseas departments that led to a proposal for free AAA ultrasound screening: the Vesalius operation. Being a consumer operation, the selection criteria were limited to age (men and women between 60 and 75 years); the age limit was lowered to 50 years in case of direct family history of AAA. More than 7000 people (as many women as men) were screened in 83 centers with a 1.70% prevalence of AAA in the age-based target population (3.12% for men, 0.27% for women). The median diameter of detected AAA was 33 mm (range 20 to 74 mm). The prevalence of AAA was 1.7% in this population. Vesalius data are consistent with those of the literature both in terms of prevalence and for cardiovascular risk factors with the important role of smoking. Lessons from Vesalius to take into consideration are: screening is warranted in men 60 years and over, especially smokers, and in female smokers. Screening beyond 75 years should be discussed. Given the importance of screening, the SFMV set up a year of national screening for AAA (Vesalius operation 2014/2015) in order to increase public and physician awareness about AAA detection, therapeutic management, and monitoring. AAA is a serious, common, disease that kills 6000 people each year. The goal of screening is cost-effective reduction in the death toll. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Combination Therapy with Atorvastatin and Amlodipine Suppresses Angiotensin II-Induced Aortic Aneurysm Formation

PubMed Central

Takahashi, Kikuyo; Matsumoto, Yasuharu; Do.e, Zhulanqiqige; Kanazawa, Masanori; Satoh, Kimio; Shimizu, Takuya; Sato, Akira; Fukumoto, Yoshihiro; Shimokawa, Hiroaki

2013-01-01

Background Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease. It is controversial whether statin and calcium channel blockers (CCBs) has an inhibitory effect on the expansion of AAA. Some studies reported that CCBs have an inhibitory effect on Rho-kinase activity. Rho-kinase plays an important role in the pathogenesis of various cardiovascular diseases. However, there is no study reporting of the association between Rho-kinase and human AAAs. Methods and Results Experimental AAA was induced in Apolipoprotein E-deficient (ApoE-/-) mice infused with angiotensin II (AngII) for 28 days. They were randomly divided into the following 5 groups; saline infusion alone (sham), AngII infusion alone, AngII infusion plus atorvastatin (10 mg/kg/day), AngII infusion plus amlodipine (1 mg/kg/day), and AngII infusion plus combination therapy with atorvastatin (10 mg/kg/day) and amlodipine (1 mg/kg/day). The combination therapy significantly suppressed AngII-induced increase in maximal aortic diameter as compared with sham, whereas each monotherapy had no inhibitory effects. The combination therapy significantly reduced AngII-induced apoptosis and elastin degradation at the AAA lesion, whereas each monotherapy did not. Moreover, Rho-kinase activity, as evaluated by the extent of phosphorylation of myosin-binding subunit (a substrate of Rho-kinase) and matrix metalloproteinase activity were significantly increased in the AngII-induced AAA lesion as compared with sham, both of which were again significantly suppressed by the combination therapy. In human aortic samples, immunohistochemistory revealed that the activity and expression of Rho-kinase was up-regulated in AAA lesion as compared with abdominal aorta from control subjects. Conclusions Rho-kinase is up-regulated in the aortic wall of human AAA. The combination therapy with amlodipine and Atorvastatin, but not each monotherapy, suppresses AngII-induced AAA formation in mice in vivo, for which Rho-kinase inhibition may be involved. PMID:23967318

Human serum cholinesterase from liver pathological samples exhibit highly elevated aryl acylamidase activity.

PubMed

Boopathy, Rathanam; Rajesh, Ramanna Valmiki; Darvesh, Sultan; Layer, Paul G

2007-05-01

Although aspartate aminotransferase (AST) and gamma-glutamyltransferase (gamma GT) enzymes are widely used as markers for liver disorders, the ubiquitous enzyme butyrylcholinesterase (BChE), synthesized in liver is also used as marker in the assessment of liver pathophysiology. This BChE enzyme in addition to its esterase activity has yet another enzymatic function designated as aryl acylamidase (AAA) activity. It is determined in in vitro based on the hydrolysis of the synthetic substrate o-nitroacetanilide. In the present study, human serum cholinesterase (BChE) activity was studied with respect to its AAA activity on the BChE protein (AAA(BChE)) in patients with liver disorders. AST and gamma GT values were taken into account in this study as known markers for liver disorders. Blood samples were grouped into 3 based on esterase activity associated with BChE protein. They are normal, low, and very low BChE activity but with markedly increased AST and gamma GT levels. These samples were tested for their respective AAA function. Association of AAA with BChE from samples was proved using BChE monoclonal antibody precipitation experiment. The absolute levels of AAA were increased as BChE activity decreased while deviating from normal samples and such deviation was directly proportional to the severity of the liver disorder. Differences between these groups became prominent after determining the ratios of AAA(BChE) to BChE activities. Samples showing very high AAA(BChE) to BChE ratio were also showing high to very high gamma GT values. These findings establish AAA(BChE) as an independently regulated enzymatic activity on BChE especially in liver disorders. Moreover, since neither the low esterase activity of BChE by itself nor increased levels of AST/gamma GT are sufficient pathological indicators, this pilot study merits replication with large sample numbers.

Angiotensin-Induced Abdominal Aortic Aneurysms in Hypercholesterolemic Mice: Role of Serum Cholesterol and Temporal Effects of Exposure

PubMed Central

Prins, Petra A.; Hill, Michael F.; Airey, David; Nwosu, Sam; Perati, Prudhvidhar R.; Tavori, Hagai; F. Linton, MacRae; Kon, Valentina; Fazio, Sergio; Sampson, Uchechukwu K.

2014-01-01

Objective Understanding variations in size and pattern of development of angiotensin II (Ang II)-induced abdominal aortic aneurysms (AAA) may inform translational research strategies. Thus, we sought insight into the temporal evolution of AAA in apolipoprotein (apo)E−/− mice. Approach A cohort of mice underwent a 4-week pump-mediated infusion of saline (n = 23) or 1500 ng/kg/min of Ang II (n = 85) and AAA development was tracked via in vivo ultrasound imaging. We adjusted for hemodynamic covariates in the regression models for AAA occurrence in relation to time. Results The overall effect of time was statistically significant (p<0.001). Compared to day 7 of AngII infusion, there was no decrease in the log odds of AAA occurrence by day 14 (−0.234, p = 0.65), but compared to day 21 and 28, the log odds decreased by 9.07 (p<0.001) and 2.35 (p = 0.04), respectively. Hemodynamic parameters were not predictive of change in aortic diameter (Δ) (SBP, p = 0.66; DBP, p = 0.66). Mean total cholesterol (TC) was higher among mice with large versus small AAA (601 vs. 422 mg/ml, p<0.0001), and the difference was due to LDL. AngII exposure was associated with 0.43 mm (95% CI, 0.27 to 0.61, p<0.0001) increase in aortic diameter; and a 100 mg/dl increase in mean final cholesterol level was associated with a 12% (95% CI, 5.68 to 18.23, p<0.0001) increase in aortic diameter. Baseline cholesterol was not associated with change in aortic diameter (p = 0.86). Conclusions These are the first formal estimates of a consistent pattern of Ang II-induced AAA development. The odds of AAA occurrence diminish after the second week of Ang II infusion, and TC is independently associated with AAA size. PMID:24465413

Increased 18F-FDG Uptake Is Predictive of Rupture in a Novel Rat Abdominal Aortic Aneurysm Rupture Model

PubMed Central

English, Sean J.; Piert, Morand R.; Diaz, Jose A.; Gordon, David; Ghosh, Abhijit; D'Alecy, Louis G.; Whitesall, Steven E.; Sharma, Ashish K.; DeRoo, Elise P.; Watt, Tessa; Su, Gang; Henke, Peter K.; Eliason, Jonathan L.; Ailawadi, Gorav; Upchurch, Gilbert R.

2015-01-01

Objective To determine whether 18F-fluorodeoxyglucose (18F-FDG) micro–positron emission tomography (micro-PET) can predict abdominal aortic aneurysm (AAA) rupture. Background An infrarenal AAA model is needed to study inflammatory mechanisms that drive rupture. 18F-FDG PET can detect vascular inflammation in animal models and patients. Methods After exposing Sprague-Dawley rats to intra-aortic porcine pancreatic elastase (PPE) (12 U/mL), AAA rupture was induced by daily, subcutaneous, β-aminopropionitrile (BAPN, 300 mg/kg, N = 24) administration. Negative control AAA animals (N = 15) underwent daily saline subcutaneous injection after PPE exposure. BAPN-exposed animals that did not rupture served as positive controls [nonruptured AAA (NRAAA) 14d, N = 9]. Rupture was witnessed using radiotelemetry. Maximum standard uptakes for 18F-FDG micro-PET studies were determined. Aortic wall PAI-1, uPA, and tPA concentrations were determined by western blot analyses. Interleukin (IL)-1β, IL-6, IL-10, and MIP-2 were determined by Bio-Plex bead array. Neutrophil and macrophage populations per high-power field were quantified. Matrix metalloproteinase (MMP) activities were determined by zymography. Results When comparing ruptured AAA (RAAA) to NRAAA 14d animals, increased focal 18F-FDG uptakes were detected at subsequent sites of rupture (P = 0.03). PAI-1 expression was significantly less in RAAA tissue (P = 0.01), with comparable uPA and decreased tPA levels (P = 0.02). IL-1β (P = 0.04), IL-6 (P = 0.001), IL-10 (P = 0.04), and MIP-2 (P = 0.02)expression, neutrophil (P = 0.02) and macrophage presence (P = 0.002), and MMP9 (P < 0.0001) activity were increased in RAAA tissue. Conclusions With this AAA rupture model, increased prerupture 18F-FDG uptake on micro-PET imaging was associated with increased inflammation in the ruptured AAA wall. 18F-FDG PET imaging may be used to monitor inflammatory changes before AAA rupture. PMID:24651130

Dosimetric comparison of peripheral NSCLC SBRT using Acuros XB and AAA calculation algorithms.

PubMed

Ong, Chloe C H; Ang, Khong Wei; Soh, Roger C X; Tin, Kah Ming; Yap, Jerome H H; Lee, James C L; Bragg, Christopher M

2017-01-01

There is a concern for dose calculation in highly heterogenous environments such as the thorax region. This study compares the quality of treatment plans of peripheral non-small cell lung cancer (NSCLC) stereotactic body radiation therapy (SBRT) using 2 calculation algorithms, namely, Eclipse Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB), for 3-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT). Four-dimensional computed tomography (4DCT) data from 20 anonymized patients were studied using Varian Eclipse planning system, AXB, and AAA version 10.0.28. A 3DCRT plan and a VMAT plan were generated using AAA and AXB with constant plan parameters for each patient. The prescription and dose constraints were benchmarked against Radiation Therapy Oncology Group (RTOG) 0915 protocol. Planning parameters of the plan were compared statistically using Mann-Whitney U tests. Results showed that 3DCRT and VMAT plans have a lower target coverage up to 8% when calculated using AXB as compared with AAA. The conformity index (CI) for AXB plans was 4.7% lower than AAA plans, but was closer to unity, which indicated better target conformity. AXB produced plans with global maximum doses which were, on average, 2% hotter than AAA plans. Both 3DCRT and VMAT plans were able to achieve D95%. VMAT plans were shown to be more conformal (CI = 1.01) and were at least 3.2% and 1.5% lower in terms of PTV maximum and mean dose, respectively. There was no statistically significant difference for doses received by organs at risk (OARs) regardless of calculation algorithms and treatment techniques. In general, the difference in tissue modeling for AXB and AAA algorithm is responsible for the dose distribution between the AXB and the AAA algorithms. The AXB VMAT plans could be used to benefit patients receiving peripheral NSCLC SBRT. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

SU-E-T-538: Evaluation of IMRT Dose Calculation Based on Pencil-Beam and AAA Algorithms.

PubMed

Yuan, Y; Duan, J; Popple, R; Brezovich, I

2012-06-01

To evaluate the accuracy of dose calculation for intensity modulated radiation therapy (IMRT) based on Pencil Beam (PB) and Analytical Anisotropic Algorithm (AAA) computation algorithms. IMRT plans of twelve patients with different treatment sites, including head/neck, lung and pelvis, were investigated. For each patient, dose calculation with PB and AAA algorithms using dose grid sizes of 0.5 mm, 0.25 mm, and 0.125 mm, were compared with composite-beam ion chamber and film measurements in patient specific QA. Discrepancies between the calculation and the measurement were evaluated by percentage error for ion chamber dose and γ〉l failure rate in gamma analysis (3%/3mm) for film dosimetry. For 9 patients, ion chamber dose calculated with AAA-algorithms is closer to ion chamber measurement than that calculated with PB algorithm with grid size of 2.5 mm, though all calculated ion chamber doses are within 3% of the measurements. For head/neck patients and other patients with large treatment volumes, γ〉l failure rate is significantly reduced (within 5%) with AAA-based treatment planning compared to generally more than 10% with PB-based treatment planning (grid size=2.5 mm). For lung and brain cancer patients with medium and small treatment volumes, γ〉l failure rates are typically within 5% for both AAA and PB-based treatment planning (grid size=2.5 mm). For both PB and AAA-based treatment planning, improvements of dose calculation accuracy with finer dose grids were observed in film dosimetry of 11 patients and in ion chamber measurements for 3 patients. AAA-based treatment planning provides more accurate dose calculation for head/neck patients and other patients with large treatment volumes. Compared with film dosimetry, a γ〉l failure rate within 5% can be achieved for AAA-based treatment planning. © 2012 American Association of Physicists in Medicine.

Association of high sensitivity C-reactive protein and abdominal aortic aneurysm: a meta-analysis and systematic review.

PubMed

Wang, Yunpeng; Shen, Guanghui; Wang, Haiyang; Yao, Ye; Sun, Qingfeng; Jing, Bao; Liu, Gaoyan; Wu, Jia; Yuan, Chao; Liu, Siqi; Liu, Xinyu; Li, Shiyong; Li, Haocheng

2017-12-01

To evaluate the association of high sensitivity C-reactive protein (hsCRP) with the presence of abdominal aortic aneurysm (AAA). Medline, Cochrane, Embase, and Google Scholar databases were searched until 22 June 2016 using the keywords predictive factors, biomarkers, abdominal aortic aneurysm, prediction, high sensitivity C-reactive protein, and hsCRP. Prospective studies, retrospective studies, and cohort studies were included. Twelve case-control studies were included in the meta-analysis with a total of 8345 patients (1977 in the AAA group and 6368 in the control group). The pooled results showed that AAA patients had higher hsCRP value than the control group (difference in means = 1.827, 95% CI = 0.010 to 3.645, p = .049). Subgroup analysis found AAA patients with medium or small aortic diameter (<50 mm) had higher hsCRP plasma levels than the control group (difference in means = 1.301, 95% CI = 0.821 to 1.781, p < .001). In patients with large aortic diameter (≥50 mm), no difference was observed in hsCRP levels between the AAA and control groups (difference in means = 1.769, 95% CI = -1.387 to 4.925, p = .272). Multi-regression analysis found the difference in means of hsCRP plasma levels between AAA and control groups decreased as aortic diameter increased (slope = -0.04, p < .001), suggesting that hsCRP levels may be inversely associated with increasing aneurysm size. Our findings suggest that hsCRP levels may possibly be used as a diagnostic biomarker for AAA patients with medium or small aortic diameter but not for AAA patients with large aortic diameter. The correlation between serum hsCRP level and AAA aneurysm is not conclusive due to the small number of included articles and between-study heterogeneity.

Anatomic characteristics of ruptured abdominal aortic aneurysm on conventional CT scans: Implications for rupture risk.

PubMed

Fillinger, Mark F; Racusin, Jessica; Baker, Robert K; Cronenwett, Jack L; Teutelink, Arno; Schermerhorn, Marc L; Zwolak, Robert M; Powell, Richard J; Walsh, Daniel B; Rzucidlo, Eva M

2004-06-01

The purpose of this study was to analyze anatomic characteristics of patients with ruptured abdominal aortic aneurysms (AAAs), with conventional two-dimensional computed tomography (CT), including comparison with control subjects matched for age, gender, and size. Records were reviewed to identify all CT scans obtained at Dartmouth-Hitchcock Medical Center or referring hospitals before emergency AAA repair performed because of rupture or acute severe pain (RUP group). CT scans obtained before elective AAA repair (ELEC group) were reviewed for age and gender match with patients in the RUP group. More than 40 variables were measured on each CT scan. Aneurysm diameter matching was achieved by consecutively deleting the largest RUP scan and the smallest ELEC scan to prevent bias. CT scans were analyzed for 259 patients with AAAs: 122 RUP and 137 ELEC. Patients were well matched for age, gender, and other demographic variables or risk factors. Maximum AAA diameter was significantly different in comparisons of all patients (RUP, 6.5 +/- 2 cm vs ELEC, 5.6 +/- 1 cm; P <.0001), and mean diameter of ruptured AAAs was 5 mm smaller in female patients (6.1 +/- 2 cm vs 6.6 +/- 2 cm; P =.007). Two hundred patients were matched for diameter, gender, and age (100 from each group; maximum AAA diameter, 6.0 +/- 1 cm vs 6.0 +/- 1 cm). Analysis of diameter-matched AAAs indicated that most variables were statistically similar in the two groups, including infrarenal neck length (17 +/- 1 mm vs 19 +/- 1 mm; P =.3), maximum thrombus thickness (25 +/- 1 mm vs 23 +/- 1 mm, P =.4), and indices of body habitus, such as [(maximum AAA diameter)/(normal suprarenal aorta diameter)] or [(maximum AAA diameter)/(L3 transverse diameter)]. Multivariate analysis controlling for gender indicated that the most significant variables for rupture were aortic tortuosity (odds ratio [OR] 3.3, indicating greater risk with no or mild tortuosity), diameter asymmetry (OR, 3.2 for a 1-cm difference in major-minor axis), and current smoking (OR, 2.7, with the greater risk in current smokers). When matched for age, gender, and diameter, ruptured AAAs tend to be less tortuous, yet have greater cross-sectional diameter asymmetry. On conventional two-dimensional CT axial sections, it appears that when diameter asymmetry is associated with low aortic tortuosity, the larger diameter on axial sections more accurately reflects rupture risk, and when diameter asymmetry is associated with moderate or severe aortic tortuosity, the smaller diameter on axial sections more accurately reflects rupture risk. Current smoking is significantly associated with rupture, even when controlling for gender and AAA anatomy.

Selective Intra-procedural AAA sac Embolization During EVAR Reduces the Rate of Type II Endoleak.

PubMed

Mascoli, C; Freyrie, A; Gargiulo, M; Gallitto, E; Pini, R; Faggioli, G; Serra, C; De Molo, C; Stella, A

2016-05-01

The pre-treatment presence of at least six efferent patent vessels (EPV) from the AAA sac and/or AAA thrombus volume ratio (VR%) <40% are considered to be positive predictive factors for persistent type II endoleak (ELIIp). The aim of the present study was to evaluate the effectiveness of sac embolization during EVAR in patients with pre-operative morphological risk factors (p-MRF) for ELIIp. Patients undergoing EVAR and intra-procedural AAA sac embolization (Group A, 2012-2013) were retrospectively selected and compared with a control group of patients with the same p-MRF, who underwent EVAR without intra-procedural sac embolization (Group B, 2008-2010). The presence of ELIIp was evaluated by duplex ultrasound at 0 and 6 months, and by contrast enhanced ultrasound at 12 months. The association between AAA diameter, age, COPD, smoking, anticoagulant therapy, and AAA sac embolization with ELIIp was evaluated using multiple logistic regression. The primary endpoint was the effectiveness of the intra-procedural AAA sac embolization for ELIIp prevention. Secondary endpoints were AAA sac evolution and freedom from ELIIp and embolization related re-interventions at 6-12 months. Seventy patients were analyzed: 26 Group A and 44 Group B; the groups were homogeneous for clinical/morphological characteristics. In Group A the median number of coils positioned in AAA sac was 4.1 (IQR 1). There were no complications related to the embolization procedures. A significantly lower number of ELIIp was detected in Group A than in Group B (8/26 vs. 33/44, respectively, p < .001) at discharge, and this was confirmed at 6-12 months (7/26 vs. 30/44 respectively, p = .001, and 5/25 vs. 32/44, respectively, p < .001). On multivariate analysis, intra-procedural AAA sac embolization was the only factor independently associated with freedom from ELIIp at 6 (OR 0.196, 95% CI 0.06-0.63; p = .007) and 12 months (OR 0.098, 95% CI 0.02-0.35; p < .001). No differences in median AAA sac diameter shrinkage were detected between the two groups at 6-12 months (p = .42 and p = .58, respectively). Freedom from ELIIp related and embolization related re-interventions was 100% in both groups, at 6 and 12 months. Selective intra-procedural AAA sac embolization in patients with p-MRF is safe and could be an effective method to reduce ELIIp. Further studies are mandatory to support these results at long-term follow up. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

3D analysis of vortical structures in an abdominal aortic aneurysm by stereoscopic PIV

NASA Astrophysics Data System (ADS)

Deplano, Valérie; Guivier-Curien, Carine; Bertrand, Eric

2016-11-01

The present work presents an experimental in vitro three-dimensional analysis of the flow dynamics in an abdominal aortic aneurysm (AAA) through stereoscopic particle image velocimetry (SPIV) measurements. The experimental set-up mimics the pathophysiological context involving a shear thinning blood analogue fluid, compliant AAA and aorto-iliac bifurcation walls and controlled inlet and outlet flow rate and pressure waveforms as well as working fluid temperature. SPIV was carefully calibrated and conducted to assess the three velocity components in the AAA volume. For the first time in the literature, the 3D vortex ring genesis, propagation, and vanishing in the AAA bulge are experimentally described and quantified. In comparison with classical 2-component PIV measurements (2C PIV), the third component of the velocity vector was shown to be of importance in such a geometry, especially, during the deceleration phase of the flow rate. The 3D velocity magnitude reached up more than 20 % of the 2D one showing that 2C PIV are definitively not accurate enough to provide a complete description of flow behaviour in an AAA. In addition to potential clinical implications of a full 3D vortex ring description in AAA evolution, the 3D in vitro experimental quantification of the flow dynamics carried out in the present study offers an interesting tool for the validation of fluid-structure interaction numerical studies dealing with AAA.

Abdominal aorta aneurysm (AAA): Is there a role for prevention and therapy using antioxidants?

PubMed

Pincemail, Joël; Defraigne, Jean-Olivier; Courtois, Audrey; Albert, Adelin; Cheramy-Bien, Jean-Paul; Sakalihasan, Natzi

2017-09-18

Abdominal aortic aneurysm (AAA) is a degenerative disease that cause mortality in people aged > 65 years. Increased reactive oxygen species (ROS) and oxidative stress seems to play a pivotal role in AAA pathogenesis. Several sources of ROS have been identified in aortic tissues using experimental models: inflammation, increased activity of NAD(P)H or NOX, over-expression of inducible nitric oxide synthase (iNOS), uncoupled endothelial nitric oxide synthase (eNOS), platelets activation and iron release from hemoglobin. Reducing oxidative stress by antioxidants has been shown to be a potential strategy for limiting AAA development. Human studies confirmed that oxidative stress and endothelial dysfunction are well associated with AAA development. Unfortunately, there is currently no evidence showing that strategies using low molecular weight antioxidants (vitamins C and E, β-carotene) as target for ROS is effective to reduce human AAA progression. However, recent epidemiological data have highlighted the positive role of a diet enriched in fruits which contain high amounts of antioxidant polyphenols. By their ability to restore endothelial function but also their capacity to stimulate enzymatic antioxidants trough activation of the Keap1/Nrf2/ARE pathway, polyphenols can represent a promising treatment target for reducing human AAA progression. Clinical studies are therefore urgently necessary to confirm such a suggestion. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The Mitochondrial m-AAA Protease Prevents Demyelination and Hair Greying.

PubMed

Wang, Shuaiyu; Jacquemyn, Julie; Murru, Sara; Martinelli, Paola; Barth, Esther; Langer, Thomas; Niessen, Carien M; Rugarli, Elena I

2016-12-01

The m-AAA protease preserves proteostasis of the inner mitochondrial membrane. It ensures a functional respiratory chain, by controlling the turnover of respiratory complex subunits and allowing mitochondrial translation, but other functions in mitochondria are conceivable. Mutations in genes encoding subunits of the m-AAA protease have been linked to various neurodegenerative diseases in humans, such as hereditary spastic paraplegia and spinocerebellar ataxia. While essential functions of the m-AAA protease for neuronal survival have been established, its role in adult glial cells remains enigmatic. Here, we show that deletion of the highly expressed subunit AFG3L2 in mature mouse oligodendrocytes provokes early-on mitochondrial fragmentation and swelling, as previously shown in neurons, but causes only late-onset motor defects and myelin abnormalities. In contrast, total ablation of the m-AAA protease, by deleting both Afg3l2 and its paralogue Afg3l1, triggers progressive motor dysfunction and demyelination, owing to rapid oligodendrocyte cell death. Surprisingly, the mice showed premature hair greying, caused by progressive loss of melanoblasts that share a common developmental origin with Schwann cells and are targeted in our experiments. Thus, while both neurons and glial cells are dependant on the m-AAA protease for survival in vivo, complete ablation of the complex is necessary to trigger death of oligodendrocytes, hinting to cell-autonomous thresholds of vulnerability to m-AAA protease deficiency.

Polymorphisms of the matrix metalloproteinase 9 gene and abdominal aortic aneurysm.

PubMed

Smallwood, L; Allcock, R; van Bockxmeer, F; Warrington, N; Palmer, L J; Iacopetta, B; Golledge, J; Norman, P E

2008-10-01

Increased matrix metalloproteinase (MMP) 9 activity has been implicated in the formation of abdominal aortic aneurysm (AAA). The aim was to explore the association between potentially functional variants of the MMP-9 gene and AAA. The -1562C > T and -1811A > T variants of the MMP-9 gene were genotyped in 678 men with an AAA (at least 30 mm in diameter) and 659 control subjects (aortic diameter 19-22 mm) recruited from a population-based trial of screening for AAA. Levels of MMP-9 were measured in a random subset of 300 cases and 84 controls. The association between genetic variants (including haplotypes) and AAA was assessed by multivariable logistic regression. There was no association between the MMP-9-1562C > T (odds ratio (OR) 0.70 (95 per cent confidence interval (c.i.) 0.27 to 1.82)) or -1811A > T (OR 0.71 (95 per cent c.i. 0.28 to 1.85)) genotypes, or the most common haplotype (OR 0.81 (95 per cent c.i. 0.62 to 1.05)) and AAA. The serum MMP-9 concentration was higher in cases than controls, and in minor allele carriers in cases and controls, although the differences were not statistically significant. In this study, the genetic tendency to higher levels of circulating MMP-9 was not associated with AAA.

Polymorphisms of the MMP-9 gene and abdominal aortic aneurysm

PubMed Central

Smallwood, Linda; Allcock, Richard; van Bockxmeer, Frank; Warrington, Nicole; Palmer, Lyle J; Iacopetta, Barry; Golledge, Jonathan; Norman, Paul E

2008-01-01

Background Increased matrix metalloproteinase-9 (MMP-9) activity has been implicated in the formation of abdominal aortic aneurysms (AAAs). The aim of the present study was to explore the association between potentially functional variants of the MMP-9 gene and AAA. Method The −1562C>T and −1811A>T variants of the MMP-9 gene were genotyped in 678 men with AAAs (>30mm in diameter) and 659 controls (aortic diameter 19−22mm) recruited from a population-based trial of screening for AAAs. The levels of MMP-9 were measured in a random subset of 300 cases and 84 controls. The association between genetic variants (including haplotypes) and AAA was assessed using multivariate logistic regression. Results There was no association between the MMP-9 −1562C>T (OR 0.70 95%CI 0.27, 1.82) or −1811A>T (OR 0.71, 95%CI 0.28, 1.85) genotypes, or the most common haplotype (OR 0.81 95%CI 0.62, 1.05), and AAA. The serum MMP-9 concentration (ng/mL) was higher in cases than controls and in minor allele carriers in cases and controls although the differences were not statistically significant. Conclusion The results suggest that a genetic tendency to have higher levels of circulating MMP-9 is not associated with AAAs. PMID:18763261

Analysis of a Typical Chinese High School Biology Textbook Using the AAAS Textbook Standards

ERIC Educational Resources Information Center

Liang, Ye; Cobern, William W.

2013-01-01

The purpose of this study was to evaluate a typical Chinese high school biology textbook using the textbook standards of the American Association for the Advancement of Science (AAAS). The data were composed of three chapters selected from the textbook. Each chapter was analyzed and rated using the AAAS textbook standards. Pearson correlations…

40 CFR 78.1 - Purpose and scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., subparts AAA through III of part 96 of this chapter or State regulations approved under § 51.124(o)(1) or... HHHH of part 60 of this chapter, subparts AA through II of part 96 of this chapter, subparts AAA... chapter. (8) Under subparts AAA through III of part 96 of this chapter, (i) The decision on the deduction...

40 CFR 280.104 - Local government bond rating test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... million or more, excluding refunded obligations, with a Moody's rating of Aaa, Aa, A, or Baa, or a Standard & Poor's rating of AAA, AA, A, or BBB. Where a local government has multiple outstanding issues... bonds of $1 million or more, excluding refunded issues and by also having a Moody's rating of Aaa, A, A...

Measurement Challenges at Low Blood Lead Levels.

PubMed

Caldwell, Kathleen L; Cheng, Po-Yung; Jarrett, Jeffery M; Makhmudov, Amir; Vance, Kathryn; Ward, Cynthia D; Jones, Robert L; Mortensen, Mary E

2017-08-01

In 2012, the Centers for Disease Control and Prevention (CDC) adopted its Advisory Committee on Childhood Lead Poisoning Prevention recommendation to use a population-based reference value to identify children and environments associated with lead hazards. The current reference value of 5 μg/dL is calculated as the 97.5th percentile of the distribution of blood lead levels (BLLs) in children 1 to 5 years old from 2007 to 2010 NHANES data. We calculated and updated selected percentiles, including the 97.5th percentile, by using NHANES 2011 to 2014 blood lead data and examined demographic characteristics of children whose blood lead was ≥90th percentile value. The 97.5th percentile BLL of 3.48 µg/dL highlighted analytical laboratory and clinical interpretation challenges of blood lead measurements ≤5 μg/dL. Review of 5 years of results for target blood lead values <11 µg/dL for US clinical laboratories participating in the CDC's voluntary Lead and Multi-Element Proficiency quality assurance program showed 40% unable to quantify and reported a nondetectable result at a target blood lead value of 1.48 µg/dL, compared with 5.5% at a target BLL of 4.60 µg/dL. We describe actions taken at the CDC's Environmental Health Laboratory in the National Center for Environmental Health, which measures blood lead for NHANES, to improve analytical accuracy and precision and to reduce external lead contamination during blood collection and analysis. Copyright © 2017 by the American Academy of Pediatrics.

External validation of Vascular Study Group of New England risk predictive model of mortality after elective abdominal aorta aneurysm repair in the Vascular Quality Initiative and comparison against established models.

PubMed

Eslami, Mohammad H; Rybin, Denis V; Doros, Gheorghe; Siracuse, Jeffrey J; Farber, Alik

2018-01-01

The purpose of this study is to externally validate a recently reported Vascular Study Group of New England (VSGNE) risk predictive model of postoperative mortality after elective abdominal aortic aneurysm (AAA) repair and to compare its predictive ability across different patients' risk categories and against the established risk predictive models using the Vascular Quality Initiative (VQI) AAA sample. The VQI AAA database (2010-2015) was queried for patients who underwent elective AAA repair. The VSGNE cases were excluded from the VQI sample. The external validation of a recently published VSGNE AAA risk predictive model, which includes only preoperative variables (age, gender, history of coronary artery disease, chronic obstructive pulmonary disease, cerebrovascular disease, creatinine levels, and aneurysm size) and planned type of repair, was performed using the VQI elective AAA repair sample. The predictive value of the model was assessed via the C-statistic. Hosmer-Lemeshow method was used to assess calibration and goodness of fit. This model was then compared with the Medicare, Vascular Governance Northwest model, and Glasgow Aneurysm Score for predicting mortality in VQI sample. The Vuong test was performed to compare the model fit between the models. Model discrimination was assessed in different risk group VQI quintiles. Data from 4431 cases from the VSGNE sample with the overall mortality rate of 1.4% was used to develop the model. The internally validated VSGNE model showed a very high discriminating ability in predicting mortality (C = 0.822) and good model fit (Hosmer-Lemeshow P = .309) among the VSGNE elective AAA repair sample. External validation on 16,989 VQI cases with an overall 0.9% mortality rate showed very robust predictive ability of mortality (C = 0.802). Vuong tests yielded a significant fit difference favoring the VSGNE over then Medicare model (C = 0.780), Vascular Governance Northwest (0.774), and Glasgow Aneurysm Score (0.639). Across the 5 risk quintiles, the VSGNE model predicted observed mortality significantly with great accuracy. This simple VSGNE AAA risk predictive model showed very high discriminative ability in predicting mortality after elective AAA repair among a large external independent sample of AAA cases performed by a diverse array of physicians nationwide. The risk score based on this simple VSGNE model can reliably stratify patients according to their risk of mortality after elective AAA repair better than other established models. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Does continuous trusted adult support in childhood impart life-course resilience against adverse childhood experiences - a retrospective study on adult health-harming behaviours and mental well-being.

PubMed

Bellis, Mark A; Hardcastle, Katie; Ford, Kat; Hughes, Karen; Ashton, Kathryn; Quigg, Zara; Butler, Nadia

2017-03-23

Adverse childhood experiences (ACEs) including child abuse and household problems (e.g. domestic violence) increase risks of poor health and mental well-being in adulthood. Factors such as having access to a trusted adult as a child may impart resilience against developing such negative outcomes. How much childhood adversity is mitigated by such resilience is poorly quantified. Here we test if access to a trusted adult in childhood is associated with reduced impacts of ACEs on adoption of health-harming behaviours and lower mental well-being in adults. Cross-sectional, face-to-face household surveys (aged 18-69 years, February-September 2015) examining ACEs suffered, always available adult (AAA) support from someone you trust in childhood and current diet, smoking, alcohol consumption and mental well-being were undertaken in four UK regions. Sampling used stratified random probability methods (n = 7,047). Analyses used chi squared, binary and multinomial logistic regression. Adult prevalence of poor diet, daily smoking and heavier alcohol consumption increased with ACE count and decreased with AAA support in childhood. Prevalence of having any two such behaviours increased from 1.8% (0 ACEs, AAA support, most affluent quintile of residence) to 21.5% (≥4 ACEs, lacking AAA support, most deprived quintile). However, the increase was reduced to 7.1% with AAA support (≥4 ACEs, most deprived quintile). Lower mental well-being was 3.27 (95% CIs, 2.16-4.96) times more likely with ≥4 ACEs and AAA support from someone you trust in childhood (vs. 0 ACE, with AAA support) increasing to 8.32 (95% CIs, 6.53-10.61) times more likely with ≥4 ACEs but without AAA support in childhood. Multiple health-harming behaviours combined with lower mental well-being rose dramatically with ACE count and lack of AAA support in childhood (adjusted odds ratio 32.01, 95% CIs 18.31-55.98, ≥4 ACEs, without AAA support vs. 0 ACEs, with AAA support). Adverse childhood experiences negatively impact mental and physical health across the life-course. Such impacts may be substantively mitigated by always having support from an adult you trust in childhood. Developing resilience in children as well as reducing childhood adversity are critical if low mental well-being, health-harming behaviours and their combined contribution to non-communicable disease are to be reduced.

Engineering Silicone Rubbers for In vitro Studies: Creating AAA Models and ILT Analogues with Physiological Properties

PubMed Central

Corbett, T.J.; Doyle, B.J.; Callanan, A.; Walsh, M.T.; McGloughlin, T.M

2010-01-01

Background In vitro studies of abdominal aortic aneurysm (AAA) have been widely reported. Frequently mock artery models with intraluminal thrombus (ILT) analogues are used to mimic the AAA in vivo. While the models used may be physiological, their properties are frequently either not reported or investigated. Method of Approach This study is concerned with the testing and characterisation of previously used vessel analogue materials and the development of new materials for the manufacture of AAA models. These materials were used in conjunction with a previously validated injection moulding technique to manufacture AAA models of ideal geometry. To determine the model properties (stiffness (β) and compliance) the diameter change of each AAA model was investigated under incrementally increasing internal pressures and compared to published in vivo studies to determine if the models behaved physiologically. A FEA study was implemented to determine if the pressure – diameter change behaviour of the models could be predicted numerically. ILT analogues were also manufactured and characterised. Ideal models were manufactured with ILT analogue internal to the aneurysm region and the effect of the ILT analogue on the model compliance and stiffness was investigated. Results The wall materials had similar properties to aortic tissue at physiological pressures (Einit 2.22MPa and 1.57MPa (aortic tissue: 1.8MPa)). ILT analogues had similar Young’s modulus to the medial layer of ILT (0.24 and 0.33MPa (ILT: 0.28MPa)). All models had aneurysm sac compliance in the physiological range (2.62 – 8.01×10-4/mmHg (AAA in vivo: 1.8 – 9.4×10-4/mmHg)). The necks of our AAA models had similar stiffness to healthy aortas (20.44 – 29.83 (healthy aortas in vivo: 17.5±5.5)). Good agreement was seen between the diameter changes due to pressurisation in the experimental and FEA wall models with a maximum error of 7.3% at 120mmHg. It was also determined that the inclusion of ILT analogue in the sac of our models could have an effect on the compliance of the model neck. Conclusions Ideal AAA models with physiological properties were manufactured. The behaviour of these models due to pressurisation was predicted using FEA, validating this technique for the future design of realistic, physiological AAA models. Addition of ILT analogues in the aneurysm sac was shown to affect neck behaviour. This could have implications for endovascular AAA repair due to the importance of the neck for stent-graft fixation. PMID:20524746

Cost-effectiveness of intensive smoking cessation therapy among patients with small abdominal aortic aneurysms.

PubMed

Mani, Kevin; Wanhainen, Anders; Lundkvist, Jonas; Lindström, David

2011-09-01

Smoking cessation is one of the few available strategies to decrease the risk for expansion and rupture of small abdominal aortic aneurysms (AAAs). The cost-effectiveness of an intensive smoking cessation therapy in patients with small AAAs identified at screening was evaluated. A Markov cohort simulation model was used to compare an 8-week smoking cessation intervention with adjuvant pharmacotherapy and annual revisits vs nonintervention among 65-year-old male smokers with a small AAA identified at screening. The smoking cessation rate was tested in one-way sensitivity analyses in the intervention group (range, 22%-57%) and in the nonintervention group (range, 3%-30%). Literature data on the effect of smoking on AAA expansion and rupture was factored into the model. The intervention was cost-effective in all tested scenarios and sensitivity analyses. The smoking cessation intervention was cost-effective due to a decreased need for AAA repair and decreased rupture rate even when disregarding the positive effects of smoking cessation on long-term survival. The incremental cost/effectiveness ratio reached the willingness-to-pay threshold value of €25,000 per life-year gained when assuming an intervention cost of > €3250 or an effect of ≤ 1% difference in long-term smoking cessation between the intervention and nonintervention groups. Smoking cessation resulted in a relative risk reduction for elective AAA repair by 9% and for rupture by 38% over 10 years of follow-up. An adequate smoking cessation intervention in patients with small AAAs identified at screening can cost-effectively increase long-term survival and decrease the need for AAA repair. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension

PubMed Central

Manela, Neta; Oliva, Moran; Ovadia, Rinat; Sikron-Persi, Noga; Ayenew, Biruk; Fait, Aaron; Galili, Gad; Perl, Avichai; Weiss, David; Oren-Shamir, Michal

2015-01-01

Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA) pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG*) of the shikimate pathway under a constitutive promoter. The presence of AroG* protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG* transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids, and phenylpropanoid pathways showed that transcription was not affected by AroG*. This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG* cells, and the relative frequencies of the different anthocyanins changed as well. PMID:26236327

Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension.

PubMed

Manela, Neta; Oliva, Moran; Ovadia, Rinat; Sikron-Persi, Noga; Ayenew, Biruk; Fait, Aaron; Galili, Gad; Perl, Avichai; Weiss, David; Oren-Shamir, Michal

2015-01-01

Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA) pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG (*)) of the shikimate pathway under a constitutive promoter. The presence of AroG(*) protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG (*) transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids, and phenylpropanoid pathways showed that transcription was not affected by AroG (*). This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG(*) cells, and the relative frequencies of the different anthocyanins changed as well.

Editor's Choice - Inequalities in Abdominal Aortic Aneurysm Screening in England: Effects of Social Deprivation and Ethnicity.

PubMed

Jacomelli, J; Summers, L; Stevenson, A; Lees, T; Earnshaw, J J

2017-06-01

Population screening for abdominal aortic aneurysm (AAA) in men is currently ongoing in several countries. The aim was to examine the effects of deprivation and ethnicity on uptake of screening for abdominal aortic aneurysm (AAA) and prevalence of AAA. This was a review of outcomes from a population screening programme using data collected contemporaneously on a bespoke national database. Men aged 65 in two annual cohorts (2013/14 and 2014/15) were invited for AAA screening. Attendance and prevalence of AAA (aortic diameter >2.9 cm) were recorded. Results were compared according to measures of social deprivation and recorded ethnicity. Some 593,032 men were invited and 461,898 attended for ultrasound screening; uptake 77.9%. Uptake was related to social deprivation: 65.1% in the most deprived decile, 84.1% in the least deprived: OR for least deprived 2.84, 95% CI 2.76-2.92, p<.0001. Men in deprived areas were more likely to actively decline screening: 6% versus 3.8% in the least deprived decile. AAA were twice as common in the most deprived compared with the least deprived decile: OR 2.1, 95% CI 1.77-2.27, p<.0001. AAA were more common in white British men than in black (OR 0.46, 95% CI 0.31-0.71) or Asian (OR 0.18, 95% CI 0.13-0.26) men. There was considerable local variation in all findings. Social deprivation affects uptake of AAA screening in 65 year old men. Local factors are the most important determinants of uptake, so solutions to improve uptake must be designed at local, not national level. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Somatic HLA Mutations Expose the Role of Class I-Mediated Autoimmunity in Aplastic Anemia and its Clonal Complications.

PubMed

Babushok, Daria V; Duke, Jamie L; Xie, Hongbo M; Stanley, Natasha; Atienza, Jamie; Perdigones, Nieves; Nicholas, Peter; Ferriola, Deborah; Li, Yimei; Huang, Hugh; Ye, Wenda; Morrissette, Jennifer J D; Kearns, Jane; Porter, David L; Podsakoff, Gregory M; Eisenlohr, Laurence C; Biegel, Jaclyn A; Chou, Stella T; Monos, Dimitrios S; Bessler, Monica; Olson, Timothy S

2017-10-10

Acquired aplastic anemia (aAA) is an acquired deficiency of early hematopoietic cells, characterized by inadequate blood production, and a predisposition to myelodysplastic syndrome (MDS) and leukemia. Although its exact pathogenesis is unknown, aAA is thought to be driven by Human Leukocyte Antigen (HLA)-restricted T cell immunity, with earlier studies favoring HLA class II-mediated pathways. Using whole exome sequencing (WES), we recently identified two aAA patients with somatic mutations in HLA class I genes. We hypothesized that HLA class I mutations are pathognomonic for autoimmunity in aAA, but were previously underappreciated because the Major Histocompatibility Complex (MHC) region is notoriously difficult to analyze by WES. Using a combination of targeted deep sequencing of HLA class I genes and single nucleotide polymorphism array (SNP-A) genotyping we screened 66 aAA patients for somatic HLA class I loss. We found somatic HLA loss in eleven patients (17%), with thirteen loss-of-function mutations in HLA-A *33:03, HLA-A *68:01, HLA-B *14:02 and HLA-B *40:02 alleles. Three patients had more than one mutation targeting the same HLA allele. Interestingly, HLA-B *14:02 and HLA-B *40:02 were significantly overrepresented in aAA patients, compared to ethnicity-matched controls. Patients who inherited the targeted HLA alleles, regardless of HLA mutation status, had a more severe disease course with more frequent clonal complications as assessed by WES, SNP-A, and metaphase cytogenetics, and more frequent secondary MDS. The finding of recurrent HLA class I mutations provides compelling evidence for a predominant HLA class I-driven autoimmunity in aAA, and establishes a novel link between aAA patients' immunogenetics and clonal evolution.

Circulating cadmium concentration and risk of aortic aneurysms: A nested case-control study within the Malmö Diet and Cancer cohort.

PubMed

Fagerberg, Björn; Borné, Yan; Sallsten, Gerd; Smith, J Gustav; Acosta, Stefan; Persson, Margaretha; Melander, Olle; Forsgard, Niklas; Gottsäter, Anders; Hedblad, Bo; Barregard, Lars; Engström, Gunnar

2017-06-01

Diet and smoking expose the general population to cadmium (Cd), which is a toxic metal that accumulates in the arterial wall. In experimental studies, Cd causes reductions in proliferation of smooth muscle cells and cellular synthesis of procollagen. The aim of this study was to examine whether blood Cd levels, a valid measure of Cd exposure, are associated with increased risk of abdominal aortic aneurysm (AAA). All middle-aged men and women enrolled in the Malmö Diet and Cancer study (n = 30 447) were followed from the baseline examination in 1991-1996 through 2009. A total of 297 cases with AAA and two randomly selected control subjects for each case, matched for age and sex, were included. Blood Cd was analysed by inductively coupled plasma mass spectrometry. Diagnoses of AAA, thoracic aortic aneurysm and aortic dissection were obtained from registers. Increased blood Cd was associated with increased risk of incident AAA after adjustment for smoking and other established risk factors for AAA. The highest tertile of blood Cd concentrations had a rate ratio of 2.5 (95% confidence interval 1.3, 5.0) for incident AAA. Concentration of blood Cd (log transformed) was not associated with AAA in never-smokers (n = 24). Blood Cd levels corresponding to the upper tertile of the distribution in the age- and sex-matched control group were associated with a 2.5-fold increase in rate ratio for incident AAA. This relationship was not found in the small group of never-smokers. Copyright © 2017. Published by Elsevier B.V.

Somatic HLA mutations expose the role of class I–mediated autoimmunity in aplastic anemia and its clonal complications

PubMed Central

Duke, Jamie L.; Xie, Hongbo M.; Stanley, Natasha; Atienza, Jamie; Perdigones, Nieves; Nicholas, Peter; Ferriola, Deborah; Li, Yimei; Huang, Hugh; Ye, Wenda; Morrissette, Jennifer J. D.; Kearns, Jane; Porter, David L.; Podsakoff, Gregory M.; Eisenlohr, Laurence C.; Biegel, Jaclyn A.; Chou, Stella T.; Monos, Dimitrios S.; Bessler, Monica; Olson, Timothy S.

2017-01-01

Acquired aplastic anemia (aAA) is an acquired deficiency of early hematopoietic cells, characterized by inadequate blood production, and a predisposition to myelodysplastic syndrome (MDS) and leukemia. Although its exact pathogenesis is unknown, aAA is thought to be driven by human leukocyte antigen (HLA)–restricted T cell immunity, with earlier studies favoring HLA class II-mediated pathways. Using whole-exome sequencing (WES), we recently identified 2 patients with aAA with somatic mutations in HLA class I genes. We hypothesized that HLA class I mutations are pathognomonic for autoimmunity in aAA, but were previously underappreciated because the major histocompatibility complex (MHC) region is notoriously difficult to analyze by WES. Using a combination of targeted deep sequencing of HLA class I genes and single nucleotide polymorphism array (SNP-A) genotyping, we screened 66 patients with aAA for somatic HLA class I loss. We found somatic HLA loss in 11 patients (17%), with 13 loss-of-function mutations in HLA-A*33:03, HLA-A*68:01, HLA-B*14:02, and HLA-B*40:02 alleles. Three patients had more than 1 mutation targeting the same HLA allele. Interestingly, HLA-B*14:02 and HLA-B*40:02 were significantly overrepresented in patients with aAA compared with ethnicity-matched controls. Patients who inherited the targeted HLA alleles, regardless of HLA mutation status, had a more severe disease course with more frequent clonal complications as assessed by WES, SNP-A, and metaphase cytogenetics, and more frequent secondary MDS. The finding of recurrent HLA class I mutations provides compelling evidence for a predominant HLA class I-driven autoimmunity in aAA and establishes a novel link between immunogenetics and clonal evolution of patients with aAA. PMID:28971166