The secreted factors responsible for pre-metastatic niche formation: old sayings and new thoughts.

PubMed

Peinado, Héctor; Lavotshkin, Simon; Lyden, David

2011-04-01

Metastasis is a multistep process that requires acquisition of malignant cell phenotypes which allow tumor cells to escape from the primary tumor site. Each of the steps during metastatic progression involves co-evolution of the tumor and its microenvironment. Although tumor cells are the driving force of metastasis, new findings suggest that the host cells within the tumor microenvironment play a key role in influencing metastatic behavior. Many of these contributing cells are derived from the bone marrow; in particular, recruited bone marrow progenitor cells generate the "pre-metastatic niche" to which the tumor cells metastasize. Analysis of the molecular mechanisms involved in pre-metastatic niche formation has revealed that secreted soluble factors are key players in bone marrow cell mobilization during metastasis. In addition, membrane vesicles derived from both tumor and host cells have recently been recognized as new candidates with important roles in the promotion of tumor growth and metastasis. This review describes old ideas and presents new insights into the role of tumor and bone marrow-derived microvesicles and exosomes in pre-metastatic niche formation and metastasis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Knockdown of stem cell regulator Oct4A in ovarian cancer reveals cellular reprogramming associated with key regulators of cytoskeleton-extracellular matrix remodelling

PubMed Central

Samardzija, Chantel; Greening, David W.; Escalona, Ruth; Chen, Maoshan; Bilandzic, Maree; Luwor, Rodney; Kannourakis, George; Findlay, Jock K.; Ahmed, Nuzhat

2017-01-01

Oct4A is a master regulator of self-renewal and pluripotency in embryonic stem cells. It is a well-established marker for cancer stem cell (CSC) in malignancies. Recently, using a loss of function studies, we have demonstrated key roles for Oct4A in tumor cell survival, metastasis and chemoresistance in in vitro and in vivo models of ovarian cancer. In an effort to understand the regulatory role of Oct4A in tumor biology, we employed the use of an ovarian cancer shRNA Oct4A knockdown cell line (HEY Oct4A KD) and a global mass spectrometry (MS)-based proteomic analysis to investigate novel biological targets of Oct4A in HEY samples (cell lysates, secretomes and mouse tumor xenografts). Based on significant differential expression, pathway and protein network analyses, and comprehensive literature search we identified key proteins involved with biologically relevant functions of Oct4A in tumor biology. Across all preparations of HEY Oct4A KD samples significant alterations in protein networks associated with cytoskeleton, extracellular matrix (ECM), proliferation, adhesion, metabolism, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and drug resistance was observed. This comprehensive proteomics study for the first time presents the Oct4A associated proteome and expands our understanding on the biological role of this stem cell regulator in carcinomas. PMID:28406185

Unknown biological effects of L-glucose, ALA, and PUFA.

PubMed

Yamada, Katsuya; Sato, Daisuke; Nakamura, Takao; Amano, Hizuru; Morimoto, Yuji

2017-09-01

Key substrates including glucose, amino acids, and fatty acids play core roles in nutrient metabolism. In this review, we describe phenomena observed when key substrates are applied to cells. We focused on three promising substrates: L-glucose derivatives, 5-aminolevulinic acid, and polyunsaturated fatty acid. Since they are assumed to give a specific reaction when they are transported into cells or metabolized in cells, they are expected to be applied in a clinical setting. We provide the latest knowledge regarding their behaviors and effects on cells.

Exogenous FABP4 increases breast cancer cell proliferation and activates the expression of fatty acid transport proteins.

PubMed

Guaita-Esteruelas, Sandra; Bosquet, Alba; Saavedra, Paula; Gumà, Josep; Girona, Josefa; Lam, Eric W-F; Amillano, Kepa; Borràs, Joan; Masana, Lluís

2017-01-01

Adipose tissue plays an important role in tumor progression, because it provides nutrients and adipokines to proliferating cells. Fatty acid binding protein 4 (FABP4) is a key adipokine for fatty acid transport. In metabolic pathologies, plasma levels of FABP4 are increased. However, the role of this circulating protein is unknown. Recent studies have demonstrated that FABP4 might have a role in tumor progression, but the molecular mechanisms involved are still unclear. In this study, we analysed the role of eFABP4 (exogenous FABP4) in breast cancer progression. MCF-7 and MDA-MB-231 breast cancer cells did not express substantial levels of FABP4 protein, but intracellular FABP4 levels increased after eFABP4 incubation. Moreover, eFABP4 enhanced the proliferation of these breast cancer cells but did not have any effect on MCF-7 and MDA-MB-231 cell migration. Additionally, eFABP4 induced the AKT and MAPK signaling cascades in breast cancer cells, and the inhibition of these pathways reduced the eFBAP4-mediated cell proliferation. Interestingly, eFABP4 treatment in MCF-7 cells increased levels of the transcription factor FoxM1 and the fatty acid transport proteins CD36 and FABP5. In summary, we showed that eFABP4 plays a key role in tumor proliferation and activates the expression of fatty acid transport proteins in MCF-7 breast cancer cells. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

MRAS: A Close but Understudied Member of the RAS Family.

PubMed

Young, Lucy C; Rodriguez-Viciana, Pablo

2018-01-08

MRAS is the closest relative to the classical RAS oncoproteins and shares most regulatory and effector interactions. However, it also has unique functions, including its ability to function as a phosphatase regulatory subunit when in complex with SHOC2 and protein phosphatase 1 (PP1). This phosphatase complex regulates a crucial step in the activation cycle of RAF kinases and provides a key coordinate input required for efficient ERK pathway activation and transformation by RAS. MRAS mutations rarely occur in cancer but deregulated expression may play a role in tumorigenesis in some settings. Activating mutations in MRAS (as well as SHOC2 and PP1) do occur in the RASopathy Noonan syndrome, underscoring a key role for MRAS within the RAS-ERK pathway. MRAS also has unique roles in cell migration and differentiation and has properties consistent with a key role in the regulation of cell polarity. Further investigations should shed light on what remains a relatively understudied RAS family member. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

The BTK Inhibitor Ibrutinib (PCI-32765) Blocks Hairy Cell Leukaemia Survival, Proliferation and BCR Signalling: A New Therapeutic Approach

PubMed Central

Sivina, Mariela; Kreitman, Robert J.; Arons, Evgeny; Ravandi, Farhad; Burger, Jan A.

2014-01-01

B cell receptor (BCR) signalling plays a critical role in the progression of several B-cell malignancies, but its role in hairy cell leukaemia (HCL) is ambiguous. Bruton tyrosine kinase (BTK), a key player in BCR signalling, migration and adhesion, can be targeted with ibrutinib, a selective, irreversible BTK inhibitor. We analysed BTK expression and function in HCL and analysed the effects of ibrutinib on HCL cells. We demonstrated uniform BTK protein expression in HCL cells. Ibrutinib significantly inhibited HCL proliferation and cell cycle progression. Accordingly, ibrutinib also reduced HCL cell survival after BCR triggering with anti-immunoglobulins (A, G, and M) and abrogated the activation of kinases downstream of the BCR (PI3K and MAPK). Ibrutinib also inhibited BCR-dependent secretion of the chemokines CCL3 and CCL4 by HCL cells. Interestingly, ibrutinib inhibited CXCL12-induced signalling, a key pathway for bone marrow homing. Collectively, our data support the clinical development of ibrutinib in patients with HCL. PMID:24697238

Role of regulatory T cell in the pathogenesis of inflammatory bowel disease.

PubMed

Yamada, Akiko; Arakaki, Rieko; Saito, Masako; Tsunematsu, Takaaki; Kudo, Yasusei; Ishimaru, Naozumi

2016-02-21

Regulatory T (Treg) cells play key roles in various immune responses. For example, Treg cells contribute to the complex pathogenesis of inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis during onset or development of that disease. Many animal models of IBD have been used to investigate factors such as pathogenic cytokines, pathogenic bacteria, and T-cell functions, including those of Treg cells. In addition, analyses of patients with IBD facilitate our understanding of the precise mechanism of IBD. This review article focuses on the role of Treg cells and outlines the pathogenesis and therapeutic strategies of IBD based on previous reports.

The nanoscale organization of signaling domains at the plasma membrane.

PubMed

Griffié, Juliette; Burn, Garth; Owen, Dylan M

2015-01-01

In this chapter, we present an overview of the role of the nanoscale organization of signaling domains in regulating key cellular processes. In particular, we illustrate the importance of protein and lipid nanodomains as triggers and mediators of cell signaling. As particular examples, we summarize the state of the art of understanding the role of nanodomains in the mounting of an immune response, cellular adhesion, intercellular communication, and cell proliferation. Thus, this chapter underlines the essential role the nanoscale organization of key signaling proteins and lipid domains. We will also see how nanodomains play an important role in the lifecycle of many pathogens relevant to human disease and therefore illustrate how these structures may become future therapeutic targets. Copyright © 2015 Elsevier Inc. All rights reserved.

Fibroblasts—a key host cell type in tumor initiation, progression, and metastasis

PubMed Central

Strell, Carina; Rundqvist, Helene

2012-01-01

Tumor initiation, growth, invasion, and metastasis occur as a consequence of a complex interplay between the host environment and cancer cells. Fibroblasts are now recognized as a key host cell type involved in host–cancer signaling. This review discusses some recent studies that highlight the roles of fibroblasts in tumor initiation, early progression, invasion, and metastasis. Some clinical studies describing the prognostic significance of fibroblast-derived markers and signatures are also discussed. PMID:22509805

Role of the DIP Molecules in DCC Signaling

DTIC Science & Technology

2001-03-01

DIP13 interacts with AKT , a key molecule for cell survival. Our results suggest that the DCC apoptotic signal is mediated by DIP13 that interferes with... AKT cell survival pathway, resulting in cell death. Finally, we have cloned DIP13 beta, suggesting that DIP13 represents a family of molecules with at...interacts with DCC through its PTB domain (Fig. 4). Interestingly, Mitsuuchi et al. (1999) identified a gene dubbed APPL that interacts with AKT , a key

Sirtuins, Bioageing, and Cancer

PubMed Central

McGuinness, D.; McGuinness, D. H.; McCaul, J. A.; Shiels, P. G.

2011-01-01

The Sirtuins are a family of orthologues of yeast Sir2 found in a wide range of organisms from bacteria to man. They display a high degree of conservation between species, in both sequence and function, indicative of their key biochemical roles. Sirtuins are heavily implicated in cell cycle, cell division, transcription regulation, and metabolism, which places the various family members at critical junctures in cellular metabolism. Typically, Sirtuins have been implicated in the preservation of genomic stability and in the prolongation of lifespan though many of their target interactions remain unknown. Sirtuins play key roles in tumourigenesis, as some have tumour-suppressor functions and others influence tumours through their control of the metabolic state of the cell. Their links to ageing have also highlighted involvement in various age-related and degenerative diseases. Here, we discuss the current understanding of the role of Sirtuins in age-related diseases while taking a closer look at their roles and functions in maintaining genomic stability and their influence on telomerase and telomere function. PMID:21766030

The bruton tyrosine kinase inhibitor ibrutinib (PCI-32765) blocks hairy cell leukaemia survival, proliferation and B cell receptor signalling: a new therapeutic approach.

PubMed

Sivina, Mariela; Kreitman, Robert J; Arons, Evgeny; Ravandi, Farhad; Burger, Jan A

2014-07-01

B cell receptor (BCR) signalling plays a critical role in the progression of several B-cell malignancies, but its role in hairy cell leukaemia (HCL) is ambiguous. Bruton tyrosine kinase (BTK), a key player in BCR signalling, as well as B cell migration and adhesion, can be targeted with ibrutinib, a selective, irreversible BTK inhibitor. We analysed BTK expression and function in HCL and analysed the effects of ibrutinib on HCL cells. We demonstrated uniform BTK protein expression in HCL cells. Ibrutinib significantly inhibited HCL proliferation and cell cycle progression. Accordingly, ibrutinib also reduced HCL cell survival after BCR triggering with anti-immunoglobulins and abrogated the activation of kinases downstream of the BCR (PI3K and MAPK). Ibrutinib also inhibited BCR-dependent secretion of the chemokines CCL3 and CCL4 by HCL cells. Interestingly, ibrutinib inhibited also CXCL12-induced signalling, a key pathway for bone marrow homing. Collectively, our data support the clinical development of ibrutinib in patients with HCL. © 2014 John Wiley & Sons Ltd.

The MqsRA Toxin-Antitoxin System from Xylella fastidiosa Plays a Key Role in Bacterial Fitness, Pathogenicity, and Persister Cell Formation.

PubMed

Merfa, Marcus V; Niza, Bárbara; Takita, Marco A; De Souza, Alessandra A

2016-01-01

Through the formation of persister cells, bacteria exhibit tolerance to multidrug and other environmental stresses without undergoing genetic changes. The toxin-antitoxin (TA) systems are involved in the formation of persister cells because they are able to induce cell dormancy. Among the TA systems, the MqsRA system has been observed to be highly induced in persister cells of Xylella fastidiosa (causal agent of citrus variegated chlorosis-CVC) activated by copper stress, and has been described in Escherichia coli as related to the formation of persister cells and biofilms. Thus, we evaluated the role of this TA system in X. fastidiosa by overexpressing the MqsR toxin, and verified that the toxin positively regulated biofilm formation and negatively cell movement, resulting in reduced pathogenicity in citrus plants. The overexpression of MqsR also increased the formation of persister cells under copper stress. Analysis of the gene and protein expression showed that this system likely has an autoregulation mechanism to express the toxin and antitoxin in the most beneficial ratio for the cell to oppose stress. Our results suggest that this TA system plays a key role in the adaptation and survival of X. fastidiosa and reveal new insights into the physiology of phytopathogen-host interactions.

The MqsRA Toxin-Antitoxin System from Xylella fastidiosa Plays a Key Role in Bacterial Fitness, Pathogenicity, and Persister Cell Formation

PubMed Central

Merfa, Marcus V.; Niza, Bárbara; Takita, Marco A.; De Souza, Alessandra A.

2016-01-01

Through the formation of persister cells, bacteria exhibit tolerance to multidrug and other environmental stresses without undergoing genetic changes. The toxin-antitoxin (TA) systems are involved in the formation of persister cells because they are able to induce cell dormancy. Among the TA systems, the MqsRA system has been observed to be highly induced in persister cells of Xylella fastidiosa (causal agent of citrus variegated chlorosis—CVC) activated by copper stress, and has been described in Escherichia coli as related to the formation of persister cells and biofilms. Thus, we evaluated the role of this TA system in X. fastidiosa by overexpressing the MqsR toxin, and verified that the toxin positively regulated biofilm formation and negatively cell movement, resulting in reduced pathogenicity in citrus plants. The overexpression of MqsR also increased the formation of persister cells under copper stress. Analysis of the gene and protein expression showed that this system likely has an autoregulation mechanism to express the toxin and antitoxin in the most beneficial ratio for the cell to oppose stress. Our results suggest that this TA system plays a key role in the adaptation and survival of X. fastidiosa and reveal new insights into the physiology of phytopathogen-host interactions. PMID:27375608

Mast Cells: Key Players in the Shadow in Oral Inflammation and in Squamous Cell Carcinoma of the Oral Cavity

PubMed Central

Gaje, Pusa Nela; Amalia Ceausu, Raluca; Jitariu, Adriana; Popovici, Ramona Amina; Raica, Marius

2016-01-01

Although mast cells (MCs) have been discovered over 130 years ago, their function was almost exclusively linked to allergic affections. At the time being, it is well known that MCs possess a great variety of roles, in both physiologic and pathologic conditions. In the oral tissues, MCs release different proinflammatory cytokines, tumor necrosis factor alpha (TNF-α), that promote leukocyte infiltration in various inflammatory states of the oral cavity. These cells play a key role in the inflammatory process and, as a consequence, their number changes in different pathologic conditions of the oral cavity, like gingivitis, periodontitis, and so on. MCs also represent a rich source of proteases, especially of mast cell tryptase and chymase, which directly degrade the extracellular matrix through their proteolytic activity and thus indirectly stimulate angiogenesis and facilitate invasion and metastasis. It may be stated that mast cells could have an impact on primary tumor development, progression, and metastases in oral squamous cell carcinoma. By understanding the role of mast cells in the pathogenesis of different inflammatory and tumor diseases of the oral cavity, these cells may become therapeutic targets that could possibly improve the prognosis and survival of these patients. PMID:27847826

Role of Mesenchymal Derived Stem Cells in Stimulating Dormant Tumor Cells to Proliferate and Form Clinical Metastases

DTIC Science & Technology

2017-07-01

that IL6 is elevated under these in vitro conditions using an ELISA -based system (Fig 1). We are now investigating the potential functional role of...narrowed our focus on DNMT1 which encodes for a DNA methyltransferase that is key in regulating global epigenetic methylation Figure 1. ELISA

Human CD134 (OX40) expressed on T cells plays a key role for human herpesvirus 6B replication after allogeneic hematopoietic stem cell transplantation.

PubMed

Nagamata, Satoshi; Nagasaka, Miwako; Kawabata, Akiko; Kishimoto, Kenji; Hasegawa, Daiichiro; Kosaka, Yoshiyuki; Mori, Takeshi; Morioka, Ichiro; Nishimura, Noriyuki; Iijima, Kazumoto; Yamada, Hideto; Kawamoto, Shinichiro; Yakushijin, Kimikazu; Matsuoka, Hiroshi; Mori, Yasuko

2018-05-01

CD134 (OX40), which is a cellular receptor for human herpesvirus-6B (HHV-6B) and expresses on activated T cells, may play a key role for HHV-6B replication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Therefore, we examined the CD134 expression on T cells and HHV-6B replication after allo-HSCT, and analyzed the correlation between them. Twenty-three patients after allo-HSCT were enrolled. The percentages of CD134-positive cells within the CD4 + and CD8 + cell populations were measured by flow cytometry, and the viral copy number of HHV-6B was simultaneously quantified by real-time PCR. The correlation between CD134 and HHV-6B viral load was then statistically analyzed. HHV-6B reactivation occurred in 11 of 23 patients (47.8%). CD134 expression was seen on T cells and was coincident with the time of peak viral load. The percentage of CD134-positive cells decreased significantly when HHV-6B DNA disappeared (p = .005 in CD4 + T cells, p = .02 in CD8 + T cells). In the 4 patients who underwent umbilical cord blood transplantation (UCBT), the viral load varied with the percentage of CD134-positive cells. In the comparison between the HHV-6B reactivation group and non-reactivation group, maximum percentages of CD134-positive cells among CD4 + T cells in reactivation group were significantly higher than those in non-reactivation group (p = .04). This is the first study to show that a correlation of CD134 expression on T cells with HHV-6B replication after allo-HSCT, especially in UCBT. The results possibly indicate that CD134 on T cells plays a key role for HHV-6B replication after allo-HSCT. Copyright © 2018 Elsevier B.V. All rights reserved.

The Snail Family in Normal and Malignant Haematopoiesis.

PubMed

Carmichael, Catherine L; Haigh, Jody J

2017-01-01

Snail family proteins are key inducers of the epithelial-mesenchymal transition (EMT), a critical process required for normal embryonic development. They have also been strongly implicated in regulating the EMT-like processes required for tumour cell invasion, migration, and metastasis. Whether these proteins also contribute to normal blood cell development, however, remains to be clearly defined. Increasing evidence supports a role for the Snail family in regulating cell survival, migration, and differentiation within the haematopoietic system, as well as potentially an oncogenic role in the malignant transformation of haematopoietic stem cells. This review will provide a broad overview of the Snail family, including key aspects of their involvement in the regulation and development of solid organ cancer, as well as a discussion on our current understanding of Snail family function during normal and malignant haematopoiesis. © 2017 S. Karger AG, Basel.

Developmental acquisition of regulomes underlies innate lymphoid cell functionality

USDA-ARS?s Scientific Manuscript database

Innate lymphoid cells (ILCs) play key roles in host defense, barrier integrity, and homeostasis, and they mirror adaptive CD4+ T helper (Th) cell subtypes in both usages of effector molecules and ·transcription factors. To better understand ILC subsets and their relationship with Th cells, we measur...

An essential role for IL-2 receptor in regulatory T cell function

PubMed Central

Levine, Andrew G; Fan, Xiying; Klein, Ulf; Zheng, Ye; Gasteiger, Georg; Feng, Yongqiang; Fontenot, Jason D.; Rudensky, Alexander Y.

2016-01-01

Regulatory T (Treg) cells, expressing abundant amounts of the IL-2 receptor (IL-2R), are reliant on IL-2 produced by activated T cells. This feature implied a key role for a simple network based on IL-2 consumption by Treg cells in their suppressor function. However, congenital deficiency in IL-2R results in reduced expression of the Treg cell lineage specification factor Foxp3, confounding experimental efforts to understand the role of IL-2R expression and signaling in Treg suppressor function. Using genetic gain and loss of function approaches, we demonstrate that IL-2 capture is dispensable for control of CD4+ T cells, but is important for limiting CD8+ T cell activation, and that IL-2R dependent STAT5 transcription factor activation plays an essential role in Treg cell suppressor function separable from T cell receptor signaling. PMID:27595233

MicroRNAs: key regulators of stem cells.

PubMed

Gangaraju, Vamsi K; Lin, Haifan

2009-02-01

The hallmark of a stem cell is its ability to self-renew and to produce numerous differentiated cells. This unique property is controlled by dynamic interplays between extrinsic signalling, epigenetic, transcriptional and post-transcriptional regulations. Recent research indicates that microRNAs (miRNAs) have an important role in regulating stem cell self-renewal and differentiation by repressing the translation of selected mRNAs in stem cells and differentiating daughter cells. Such a role has been shown in embryonic stem cells, germline stem cells and various somatic tissue stem cells. These findings reveal a new dimension of gene regulation in controlling stem cell fate and behaviour.

FANCD2 limits replication stress and genome instability in cells lacking BRCA2

PubMed Central

Buffa, Francesca M.; McDermott, Ultan; Tarsounas, Madalena

2016-01-01

The tumor suppressor BRCA2 plays a key role in genome integrity by promoting replication fork stability and homologous recombination (HR) DNA repair. Here we report that human cancer cells lacking BRCA2 rely on the Fanconi anemia protein FANCD2 to limit replication fork progression and genomic instability. Our results identify a novel role for FANCD2 in limiting constitutive replication stress in BRCA2-deficient cells, which impacts on cell survival and treatment responses. PMID:27322732

The Autoimmune Skin Disease Bullous Pemphigoid: The Role of Mast Cells in Autoantibody-Induced Tissue Injury

PubMed Central

Fang, Hui; Zhang, Yang; Li, Ning; Wang, Gang; Liu, Zhi

2018-01-01

Bullous pemphigoid (BP) is an autoimmune and inflammatory skin disease associated with subepidermal blistering and autoantibodies directed against the hemidesmosomal components BP180 and BP230. Animal models of BP were developed by passively transferring anti-BP180 IgG into mice, which recapitulates the key features of human BP. By using these in vivo model systems, key cellular and molecular events leading to the BP disease phenotype are identified, including binding of pathogenic IgG to its target, complement activation of the classical pathway, mast cell degranulation, and infiltration and activation of neutrophils. Proteinases released by infiltrating neutrophils cleave BP180 and other hemidesmosome-associated proteins, causing DEJ separation. Mast cells and mast cell-derived mediators including inflammatory cytokines and proteases are increased in lesional skin and blister fluids of BP. BP animal model evidence also implicates mast cells in the pathogenesis of BP. However, recent studies questioned the pathogenic role of mast cells in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and epidermolysis bullosa acquisita. This review highlights the current knowledge on BP pathophysiology with a focus on a potential role for mast cells in BP and mast cell-related critical issues needing to be addressed in the future. PMID:29545809

Vascular Endothelial Growth Factor (VEGF) Promotes Assembly of the p130Cas Interactome to Drive Endothelial Chemotactic Signaling and Angiogenesis.

PubMed

Evans, Ian M; Kennedy, Susan A; Paliashvili, Ketevan; Santra, Tapesh; Yamaji, Maiko; Lovering, Ruth C; Britton, Gary; Frankel, Paul; Kolch, Walter; Zachary, Ian C

2017-02-01

p130Cas is a polyvalent adapter protein essential for cardiovascular development, and with a key role in cell movement. In order to identify the pathways by which p130Cas exerts its biological functions in endothelial cells we mapped the p130Cas interactome and its dynamic changes in response to VEGF using high-resolution mass spectrometry and reconstruction of protein interaction (PPI) networks with the aid of multiple PPI databases. VEGF enriched the p130Cas interactome in proteins involved in actin cytoskeletal dynamics and cell movement, including actin-binding proteins, small GTPases and regulators or binders of GTPases. Detailed studies showed that p130Cas association of the GTPase-binding scaffold protein, IQGAP1, plays a key role in VEGF chemotactic signaling, endothelial polarization, VEGF-induced cell migration, and endothelial tube formation. These findings indicate a cardinal role for assembly of the p130Cas interactome in mediating the cell migratory response to VEGF in angiogenesis, and provide a basis for further studies of p130Cas in cell movement. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Do myoepithelial cells hold the key for breast tumorprogression?

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

Polyak, Kornelia; Hu, Min

2005-11-18

Mammary myoepithelial cells have been the foster child of breast cancer biology and have been largely ignored since they were considered to be less important for tumorigenesis than luminal epithelial cells from which most of breast carcinomas are thought to arise. In recent years as our knowledge in stem cell biology and the cellular microenvironment has been increasing myoepithelial cells are slowly starting to gain more attention. Emerging data raise the hypothesis if myoepithelial cells play a key role in breast tumor progression by regulating the in situ to invasive carcinoma transition and if myoepithelial cells are part of themore » mammary stem cell niche. Paracrine interactions between myoepithelial and luminal epithelial cells are known to be important for cell cycle arrest, establishing epithelial cell polarity, and inhibiting migration and invasion. Based on these functions normal mammary myoepithelial cells have been called ''natural tumor suppressors''. However, during tumor progression myoepithelial cells seem to loose these properties and eventually they themselves diminish as tumors become invasive. Better understanding of myoepithelial cell function and their role in tumor progression may lead to their exploitation for cancer therapeutic and preventative measures.« less

The impact of eicosanoids on the crosstalk between innate and adaptive immunity: the key roles of dendritic cells.

PubMed

Harizi, H; Gualde, N

2005-06-01

The innate immune response is essentially the first line of defense against an invading pathogen. Through specialized receptors, known as pattern recognition receptors, especially Toll-like receptors, specialized cells of myeloid origin, including macrophages and dendritic cells (DCs) are able to phagocytose microorganisms and induce an innate inflammatory response. Although B and T lymphocytes recognize tissue antigens with high specificity, they are unable to initiate immune responses. The decision to activate an appropriate immune response is made by unique DC, the most professional antigen-presenting cells (APCs) which control the responses of several types of lymphocytes and play central role in the transition between innate and adaptive immunity. Increased secretion of inflammatory endogenous mediators such as cytokines and arachidonic acid-derived lipid mediators, also termed eicosanoids, can activate APC, particularly DC, which in turn induce an adaptive immune response. There is an increasing evidence that eicosanoids play an important role in connecting innate and adaptive immunity by acting on cells of both systems. Prostanoids, a major class of eicosanoids, have a great impact on inflammatory and immune responses. PGE(2) is one of the best known and most well-characterized prostanoids in terms of immunomodulation. Although cytokines are known as key regulators of immunity, eicosanoids, including PGE(2), PGD(2), LTB(4), and LTC(4), may also affect cells of immune system by modulating cytokine release, cell differentiation, survival, migration, antigen presentation, and apoptosis. By acting on various aspects of immune and inflammatory reactions, these lipid mediators emerge as key regulators of the crosstalk between innate and adaptive immunity.

The Morphogenetic Role of Apoptosis.

PubMed

Monier, Bruno; Suzanne, Magali

2015-01-01

Beyond safeguarding the organism from cell misbehavior and controlling cell number, apoptosis (or programmed cell death) plays key roles during animal development. In particular, it has long been acknowledged that apoptosis participates in tissue remodeling. Yet, until recently, this contribution to morphogenesis was considered as "passive," consisting simply in the local removal of unnecessary cells leading to a new shape. In recent years, applying live imaging methods to study the dynamics of apoptosis in various contexts has considerably modified our vision, revealing that in fact, dying cells remodel their neighborhood actively. Here, we first focus on the intrinsic cellular properties of apoptotic cells during their dismantling, in particular the role of the cytoskeleton during their characteristic morphological changes. Second, we review the various roles of apoptosis during developmental morphogenetic processes and pinpoint the crucial role of live imaging in revealing new concepts, in particular apoptosis as a generator of mechanical forces to control tissue dynamics. © 2015 Elsevier Inc. All rights reserved.

DNA recombination protein-dependent mechanism of homoplasmy and its proposed functions.

PubMed

Shibata, Takehiko; Ling, Feng

2007-01-01

Homoplasmy is a basic genetic state of mitochondria, in which all of the hundreds to thousands of mitochondrial (mt)DNA copies within a cell or an individual have the same nucleotide-sequence. It was recently found that "vegetative segregation" to generate homoplasmic cells is an active process under genetic control. In the yeast Saccharomyces cerevisiae, the Mhr1 protein which catalyzes a key reaction in mtDNA homologous recombination, plays a pivotal role in vegetative segregation. Conversely, within the nuclear genome, homologous DNA recombination causes genetic diversity. Considering these contradictory roles of this key reaction in DNA recombination, possible functions of homoplasmy are discussed.

Intracellular GPCRs Play Key Roles in Synaptic Plasticity.

PubMed

Jong, Yuh-Jiin I; Harmon, Steven K; O'Malley, Karen L

2018-02-16

The trillions of synaptic connections within the human brain are shaped by experience and neuronal activity, both of which underlie synaptic plasticity and ultimately learning and memory. G protein-coupled receptors (GPCRs) play key roles in synaptic plasticity by strengthening or weakening synapses and/or shaping dendritic spines. While most studies of synaptic plasticity have focused on cell surface receptors and their downstream signaling partners, emerging data point to a critical new role for the very same receptors to signal from inside the cell. Intracellular receptors have been localized to the nucleus, endoplasmic reticulum, lysosome, and mitochondria. From these intracellular positions, such receptors may couple to different signaling systems, display unique desensitization patterns, and/or show distinct patterns of subcellular distribution. Intracellular GPCRs can be activated at the cell surface, endocytosed, and transported to an intracellular site or simply activated in situ by de novo ligand synthesis, diffusion of permeable ligands, or active transport of non-permeable ligands. Current findings reinforce the notion that intracellular GPCRs play a dynamic role in synaptic plasticity and learning and memory. As new intracellular GPCR roles are defined, the need to selectively tailor agonists and/or antagonists to both intracellular and cell surface receptors may lead to the development of more effective therapeutic tools.

Evidence for the Role of B Cells and Immunoglobulins in the Pathogenesis of Multiple Sclerosis

PubMed Central

Wootla, Bharath; Denic, Aleksandar; Keegan, B. Mark; Winters, Jeffrey L.; Astapenko, David; Warrington, Arthur E.; Bieber, Allan J.; Rodriguez, Moses

2011-01-01

The pathogenesis of multiple sclerosis (MS) remains elusive. Recent reports advocate greater involvement of B cells and immunoglobulins in the initiation and propagation of MS lesions at different stages of their ontogeny. The key role of B cells and immunoglobulins in pathogenesis was initially identified by studies in which patients whose fulminant attacks of demyelination did not respond to steroids experienced remarkable functional improvement following plasma exchange. The positive response to Rituximab in Phase II clinical trials of relapsing-remitting MS confirms the role of B cells. The critical question is how B cells contribute to MS. In this paper, we discuss both the deleterious and the beneficial roles of B cells and immunoglobulins in MS lesions. We provide alternative hypotheses to explain both damaging and protective antibody responses. PMID:21961063

The Role of Structural Extracellular Matrix Proteins in Urothelial Bladder Cancer (Review)

PubMed Central

Brunner, Andrea; Tzankov, Alexandar

2007-01-01

The extracellular matrix (ECM) plays a key role in the modulation of cancer cell invasion. In urothelial carcinoma of the bladder (UC) the role of ECM proteins has been widely studied. The mechanisms, which are involved in the development of invasion, progression and generalization, are complex, depending on the interaction of ECM proteins with each other as well as with cancer cells. The following review will focus on the pathogenetic role and prognostic value of structural proteins, such as laminins, collagens, fibronectin (FN), tenascin (Tn-C) and thrombospondin 1 (TSP1) in UC. In addition, the role of integrins mediating the interaction of ECM molecules and cancer cells will be addressed, since integrin-mediated FN, Tn-C and TSP1 interactions seem to play an important role during tumor cell invasion and angiogenesis. PMID:19662222

Green tea EGCG, T-cell function, and T-cell-mediated autoimmune encephalomyelitis

USDA-ARS?s Scientific Manuscript database

Autoimmune diseases are common, disabling immune disorders affecting millions of people. Recent studies indicate that dysregulated balance of different CD4+ T-cell subpopulations plays a key role in immune pathogenesis of several major autoimmune diseases. Green tea and its active ingredient, epigal...

The ULT trxG Fatcors play a role in Arabidopsis Fertilization

USDA-ARS?s Scientific Manuscript database

Trithorax group (trxG) and Polycomb group (PcG) proteins are epigenetic modifiers that play key roles in eukaryotic development by promoting active or repressive gene expression states, respectively. Although PcG proteins have well-defined roles in controlling developmental transitions, cell fate de...

A novel enteric neuron–glia coculture system reveals the role of glia in neuronal development

PubMed Central

Le Berre‐Scoul, Catherine; Chevalier, Julien; Oleynikova, Elena; Cossais, François; Talon, Sophie; Neunlist, Michel

2016-01-01

Key points Unlike astrocytes in the brain, the potential role of enteric glial cells (EGCs) in the formation of the enteric neuronal circuit is currently unknown.To examine the role of EGCs in the formation of the neuronal network, we developed a novel neuron‐enriched culture model from embryonic rat intestine grown in indirect coculture with EGCs.We found that EGCs shape axonal complexity and synapse density in enteric neurons, through purinergic‐ and glial cell line‐derived neurotrophic factor‐dependent pathways.Using a novel and valuable culture model to study enteric neuron–glia interactions, our study identified EGCs as a key cellular actor regulating neuronal network maturation. Abstract In the nervous system, the formation of neuronal circuitry results from a complex and coordinated action of intrinsic and extrinsic factors. In the CNS, extrinsic mediators derived from astrocytes have been shown to play a key role in neuronal maturation, including dendritic shaping, axon guidance and synaptogenesis. In the enteric nervous system (ENS), the potential role of enteric glial cells (EGCs) in the maturation of developing enteric neuronal circuit is currently unknown. A major obstacle in addressing this question is the difficulty in obtaining a valuable experimental model in which enteric neurons could be isolated and maintained without EGCs. We adapted a cell culture method previously developed for CNS neurons to establish a neuron‐enriched primary culture from embryonic rat intestine which was cultured in indirect coculture with EGCs. We demonstrated that enteric neurons grown in such conditions showed several structural, phenotypic and functional hallmarks of proper development and maturation. However, when neurons were grown without EGCs, the complexity of the axonal arbour and the density of synapses were markedly reduced, suggesting that glial‐derived factors contribute strongly to the formation of the neuronal circuitry. We found that these effects played by EGCs were mediated in part through purinergic P2Y1 receptor‐ and glial cell line‐derived neurotrophic factor‐dependent pathways. Using a novel and valuable culture model to study enteric neuron–glia interactions, our study identified EGCs as a key cellular actor required for neuronal network maturation. PMID:27436013

E-cadherin junction formation involves an active kinetic nucleation process

PubMed Central

Biswas, Kabir H.; Hartman, Kevin L.; Yu, Cheng-han; Harrison, Oliver J.; Song, Hang; Smith, Adam W.; Huang, William Y. C.; Lin, Wan-Chen; Guo, Zhenhuan; Padmanabhan, Anup; Troyanovsky, Sergey M.; Dustin, Michael L.; Shapiro, Lawrence; Honig, Barry; Zaidel-Bar, Ronen; Groves, Jay T.

2015-01-01

Epithelial (E)-cadherin-mediated cell−cell junctions play important roles in the development and maintenance of tissue structure in multicellular organisms. E-cadherin adhesion is thus a key element of the cellular microenvironment that provides both mechanical and biochemical signaling inputs. Here, we report in vitro reconstitution of junction-like structures between native E-cadherin in living cells and the extracellular domain of E-cadherin (E-cad-ECD) in a supported membrane. Junction formation in this hybrid live cell-supported membrane configuration requires both active processes within the living cell and a supported membrane with low E-cad-ECD mobility. The hybrid junctions recruit α-catenin and exhibit remodeled cortical actin. Observations suggest that the initial stages of junction formation in this hybrid system depend on the trans but not the cis interactions between E-cadherin molecules, and proceed via a nucleation process in which protrusion and retraction of filopodia play a key role. PMID:26290581

E-cadherin junction formation involves an active kinetic nucleation process

DOE PAGES

Biswas, Kabir H.; Hartman, Kevin L.; Yu, Cheng -han; ...

2015-08-19

Epithelial (E)-cadherin-mediated cell–cell junctions play important roles in the development and maintenance of tissue structure in multicellular organisms. E-cadherin adhesion is thus a key element of the cellular microenvironment that provides both mechanical and biochemical signaling inputs. Here, we report in vitro reconstitution of junction-like structures between native E-cadherin in living cells and the extracellular domain of E-cadherin in a supported membrane. Junction formation in this hybrid live cell-supported membrane configuration requires both active processes within the living cell and a supported membrane with low E-cad-ECD mobility. The hybrid junctions recruit α-catenin and exhibit remodeled cortical actin. Observations suggest thatmore » the initial stages of junction formation in this hybrid system depend on the trans but not the cis interactions between E-cadherin molecules, and proceed via a nucleation process in which protrusion and retraction of filopodia play a key role.« less

E-cadherin junction formation involves an active kinetic nucleation process

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

Biswas, Kabir H.; Hartman, Kevin L.; Yu, Cheng -han

Epithelial (E)-cadherin-mediated cell–cell junctions play important roles in the development and maintenance of tissue structure in multicellular organisms. E-cadherin adhesion is thus a key element of the cellular microenvironment that provides both mechanical and biochemical signaling inputs. Here, we report in vitro reconstitution of junction-like structures between native E-cadherin in living cells and the extracellular domain of E-cadherin in a supported membrane. Junction formation in this hybrid live cell-supported membrane configuration requires both active processes within the living cell and a supported membrane with low E-cad-ECD mobility. The hybrid junctions recruit α-catenin and exhibit remodeled cortical actin. Observations suggest thatmore » the initial stages of junction formation in this hybrid system depend on the trans but not the cis interactions between E-cadherin molecules, and proceed via a nucleation process in which protrusion and retraction of filopodia play a key role.« less

Complement-Mediated Regulation of Metabolism and Basic Cellular Processes.

PubMed

Hess, Christoph; Kemper, Claudia

2016-08-16

Complement is well appreciated as a critical arm of innate immunity. It is required for the removal of invading pathogens and works by directly destroying them through the activation of innate and adaptive immune cells. However, complement activation and function is not confined to the extracellular space but also occurs within cells. Recent work indicates that complement activation regulates key metabolic pathways and thus can impact fundamental cellular processes, such as survival, proliferation, and autophagy. Newly identified functions of complement include a key role in shaping metabolic reprogramming, which underlies T cell effector differentiation, and a role as a nexus for interactions with other effector systems, in particular the inflammasome and Notch transcription-factor networks. This review focuses on the contributions of complement to basic processes of the cell, in particular the integration of complement with cellular metabolism and the potential implications in infection and other disease settings. Copyright © 2016 Elsevier Inc. All rights reserved.

Movers and shakers: cell cytoskeleton in cancer metastasis.

PubMed

Fife, C M; McCarroll, J A; Kavallaris, M

2014-12-01

Metastasis is responsible for the greatest number of cancer deaths. Metastatic disease, or the movement of cancer cells from one site to another, is a complex process requiring dramatic remodelling of the cell cytoskeleton. The various components of the cytoskeleton, actin (microfilaments), microtubules (MTs) and intermediate filaments, are highly integrated and their functions are well orchestrated in normal cells. In contrast, mutations and abnormal expression of cytoskeletal and cytoskeletal-associated proteins play an important role in the ability of cancer cells to resist chemotherapy and metastasize. Studies on the role of actin and its interacting partners have highlighted key signalling pathways, such as the Rho GTPases, and downstream effector proteins that, through the cytoskeleton, mediate tumour cell migration, invasion and metastasis. An emerging role for MTs in tumour cell metastasis is being unravelled and there is increasing interest in the crosstalk between key MT interacting proteins and the actin cytoskeleton, which may provide novel treatment avenues for metastatic disease. Improved understanding of how the cytoskeleton and its interacting partners influence tumour cell migration and metastasis has led to the development of novel therapeutics against aggressive and metastatic disease. This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24. © 2014 The British Pharmacological Society.

Movers and shakers: cell cytoskeleton in cancer metastasis

PubMed Central

Fife, C M; McCarroll, J A; Kavallaris, M

2014-01-01

Metastasis is responsible for the greatest number of cancer deaths. Metastatic disease, or the movement of cancer cells from one site to another, is a complex process requiring dramatic remodelling of the cell cytoskeleton. The various components of the cytoskeleton, actin (microfilaments), microtubules (MTs) and intermediate filaments, are highly integrated and their functions are well orchestrated in normal cells. In contrast, mutations and abnormal expression of cytoskeletal and cytoskeletal-associated proteins play an important role in the ability of cancer cells to resist chemotherapy and metastasize. Studies on the role of actin and its interacting partners have highlighted key signalling pathways, such as the Rho GTPases, and downstream effector proteins that, through the cytoskeleton, mediate tumour cell migration, invasion and metastasis. An emerging role for MTs in tumour cell metastasis is being unravelled and there is increasing interest in the crosstalk between key MT interacting proteins and the actin cytoskeleton, which may provide novel treatment avenues for metastatic disease. Improved understanding of how the cytoskeleton and its interacting partners influence tumour cell migration and metastasis has led to the development of novel therapeutics against aggressive and metastatic disease. Linked Articles This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24 PMID:24665826

Over-expression of Thioredoxin-1 mediates growth, survival, and chemoresistance and is a druggable target in diffuse large B-cell lymphoma

PubMed Central

Li, Changping; Thompson, Michael A.; Tamayo, Archito T.; Zuo, Zhuang; Lee, John; Vega, Francisco; Ford, Richard J.; Pham, Lan V.

2012-01-01

Diffuse Large B cell lymphomas (DLBCL) are the most prevalent of the non-Hodgkin lymphomas and are currently initially treated fairly successfully, but frequently relapse as refractory disease, resulting in poor salvage therapy options and short survival. The greatest challenge in improving survival of DLBCL patients is overcoming chemo-resistance, whose basis is poorly understood. Among the potential mediators of DLBCL chemo-resistance is the thioredxoin (Trx) family, primarily because Trx family members play critical roles in the regulation of cellular redox homeostasis, and recent studies have indicated that dysregulated redox homeostasis also plays a key role in chemoresistance. In this study, we showed that most of the DLBCL-derived cell lines and primary DLBCL cells express higher basal levels of Trx-1 than normal B cells and that Trx-1 expression level is associated with decreased patients survival. Our functional studies showed that inhibition of Trx-1 by small interfering RNA or a Trx-1 inhibitor (PX-12) inhibited DLBCL cell growth, clonogenicity, and also sensitized DLBCL cells to doxorubicin-induced cell growth inhibition in vitro. These results indicate that Trx-1 plays a key role in cell growth and survival, as well as chemoresistance, and is a potential target to overcome drug resistance in relapsed/refractory DLBCL. PMID:22447839

On the role of autophagy in human diseases: a gender perspective

PubMed Central

Lista, Pasquale; Straface, Elisabetta; Brunelleschi, Sandra; Franconi, Flavia; Malorni, Walter

2011-01-01

Abstract Cytopathological features of cells from males and females, i.e. XX and XY isolated cells, have been demonstrated to represent a key variable in the mechanism underlying gender disparity in human diseases. Major insights came from the studies of gender differences in cell fate, e.g. in apoptotic susceptibility. We report here some novel insights recently emerged from literature that are referred as to a cytoprotection mechanism by which cells recycle cytoplasm and dispose of excess or defective organelles, i.e. autophagy. Autophagy and related genes have first been identified in yeast. Orthologue genes have subsequently been found in other organisms, including human beings. This stimulated the research in the field and, thanks to the use of molecular genetics and cell biology in different model systems, autophagy gained the attention of several research groups operating to analyse the pathogenetic mechanisms of human diseases. It remains unclear, however, whether autophagy can exert a protective effect or instead contribute to the pathogenesis of important human diseases. On the basis of the growing importance of sex/gender as key determinant of human pathology and of the known differences between males and females in the onset, progression, drug susceptibility and outcome of a plethora of diseases, the idea that autophagy could represent key and critical factor should be taken into account. In the review, we summarize our current knowledge about the role of autophagy in some paradigmatic human diseases (cancer, neurodegenerative, autoimmune, cardiovascular) and the role of ‘cell sex’ differences in this context. PMID:21362130

Satellite cells in human skeletal muscle plasticity

PubMed Central

Snijders, Tim; Nederveen, Joshua P.; McKay, Bryon R.; Joanisse, Sophie; Verdijk, Lex B.; van Loon, Luc J. C.; Parise, Gianni

2015-01-01

Skeletal muscle satellite cells are considered to play a crucial role in muscle fiber maintenance, repair and remodeling. Our knowledge of the role of satellite cells in muscle fiber adaptation has traditionally relied on in vitro cell and in vivo animal models. Over the past decade, a genuine effort has been made to translate these results to humans under physiological conditions. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair/remodeling in response to exercise. Mounting evidence indicates that aging has a profound impact on the regulation of satellite cells in human skeletal muscle. Yet, the precise role of satellite cells in the development of muscle fiber atrophy with age remains unresolved. This review seeks to integrate recent results from in vivo human studies on satellite cell function in muscle fiber repair/remodeling in the wider context of satellite cell biology whose literature is largely based on animal and cell models. PMID:26557092

The essential role of G protein-coupled receptor (GPCR) signaling in regulating T cell immunity.

PubMed

Wang, Dashan

2018-06-01

The aim of this paper is to clarify the critical role of GPCR signaling in T cell immunity. The G protein-coupled receptors (GPCRs) are the most common targets in current pharmaceutical industry, and represent the largest and most versatile family of cell surface communicating molecules. GPCRs can be activated by a diverse array of ligands including neurotransmitters, chemokines as well as sensory stimuli. Therefore, GPCRs are involved in many key cellular and physiological processes, such as sense of light, taste and smell, neurotransmission, metabolism, endocrine and exocrine secretion. In recent years, GPCRs have been found to play an important role in immune system. T cell is an important type of immune cell, which plays a central role in cell-mediated immunity. A variety of GPCRs and their signaling mediators (RGS proteins, GRKs and β-arrestin) have been found to express in T cells and involved T cell-mediated immunity. We will summarize the role of GPCR signaling and their regulatory molecules in T cell activation, homeostasis and function in this article. GPCR signaling plays an important role in T cell activation, homeostasis and function. GPCR signaling is critical in regulating T cell immunity.

Skin immune sentinels in health and disease

PubMed Central

Nestle, Frank O.; Di Meglio, Paola; Qin, Jian-Zhong; Nickoloff, Brian J.

2010-01-01

Human skin and its immune cells provide essential protection of the human body from injury and infection. Recent studies reinforce the importance of keratinocytes as sensors of danger through alert systems such as the inflammasome. In addition, newly identified CD103+ dendritic cells are strategically positioned for cross-presentation of skin-tropic pathogens and accumulating data highlight a key role of tissue-resident rather than circulating T cells in skin homeostasis and pathology. This Review focuses on recent progress in dissecting the functional role of skin immune cells in skin disease. PMID:19763149

Skin immune sentinels in health and disease.

PubMed

Nestle, Frank O; Di Meglio, Paola; Qin, Jian-Zhong; Nickoloff, Brian J

2009-10-01

Human skin and its immune cells provide essential protection of the human body from injury and infection. Recent studies reinforce the importance of keratinocytes as sensors of danger through alert systems such as the inflammasome. In addition, newly identified CD103(+) dendritic cells are strategically positioned for cross-presentation of skin-tropic pathogens and accumulating data highlight a key role of tissue-resident rather than circulating T cells in skin homeostasis and pathology. This Review focuses on recent progress in dissecting the functional role of skin immune cells in skin disease.

Glucose metabolism regulates T cell activation, differentiation, and functions.

PubMed

Palmer, Clovis S; Ostrowski, Matias; Balderson, Brad; Christian, Nicole; Crowe, Suzanne M

2015-01-01

The adaptive immune system is equipped to eliminate both tumors and pathogenic microorganisms. It requires a series of complex and coordinated signals to drive the activation, proliferation, and differentiation of appropriate T cell subsets. It is now established that changes in cellular activation are coupled to profound changes in cellular metabolism. In addition, emerging evidence now suggest that specific metabolic alterations associated with distinct T cell subsets may be ancillary to their differentiation and influential in their immune functions. The "Warburg effect" originally used to describe a phenomenon in which most cancer cells relied on aerobic glycolysis for their growth is a key process that sustain T cell activation and differentiation. Here, we review how different aspects of metabolism in T cells influence their functions, focusing on the emerging role of key regulators of glucose metabolism such as HIF-1α. A thorough understanding of the role of metabolism in T cell function could provide insights into mechanisms involved in inflammatory-mediated conditions, with the potential for developing novel therapeutic approaches to treat these diseases.

c-Myc plays a key role in TADs-induced apoptosis and cell cycle arrest in human hepatocellular carcinoma cells.

PubMed

Zhang, Dongdong; Qi, Junpeng; Liu, Rui; Dai, Bingling; Ma, Weina; Zhan, Yingzhuan; Zhang, Yanmin

2015-01-01

Cancer cell growth is complicated progression which is regulated and controlled by multiple factors including cell cycle, migration and apoptosis. In present study, we report that TADs, a novel derivative of taspine, has an essential role in resisting hepatocellular carcinoma growth (including arrest cell cycle) and migration, and inducing cell apoptosis. Our findings demonstrated that the TADs showed good inhibition on the hepatoma cell growth and migration, and good action on apoptosis induction. Using genome-wide microarray analysis, we found the down-regulated growth and apoptosis factors, and selected down-regulated genes were confirmed by Western blot. Knockdown of a checkpoint c-Myc by siRNA significantly attenuated tumor inhibition and apoptosis effects of TADs. Moreover, our results indicated TADs could simultaneously increase cyclin D1 protein levels and decrease amount of cyclin E, cyclin B1 and cdc2 of the cycle proteins, and also TADs reduced Bcl-2 expression, and upregulated Bad, Bak and Bax activities. In conclusion, these results illustrated that TADs is a key factor in growth and apoptosis signaling inhibitor, has potential in cancer therapy.

Learning from Science Text: Role of an Elaborate Analogy. Reading Research Report No. 71.

ERIC Educational Resources Information Center

Glynn, Shawn M.

A study examined the role that an elaborate analogy can play when high school students learn a concept from a leading science textbook. The elaborate analogy had graphic and text components that integrated and mapped key features from the analogy (a factory) to the target concept (an animal cell). The target features were parts of the cell and, by…

Problem-Solving Test: Analysis of the Role of Cyclin B

ERIC Educational Resources Information Center

Szeberenyi, Jozsef

2011-01-01

An experiment is described in this test that was designed to study the role of the cyclin B protein in a cell-free system. The work was performed in the lab of Tim Hunt who, together with Hartwell and Nurse, received the Nobel Prize in Physiology or Medicine in 2001 "for their discoveries of key chemicals that regulate the cell division cycle." It…

Connecting Teratogen-Induced Congenital Heart Defects to Neural Crest Cells and Their Effect on Cardiac Function

PubMed Central

Karunamuni, Ganga H.; Ma, Pei; Gu, Shi; Rollins, Andrew M.; Jenkins, Michael W.; Watanabe, Michiko

2014-01-01

Neural crest cells play many key roles in embryonic development, as demonstrated by the abnormalities that result from their specific absence or dysfunction. Unfortunately, these key cells are particularly sensitive to abnormalities in various intrinsic and extrinsic factors, such as genetic deletions or ethanol-exposure that lead to morbidity and mortality for organisms. This review discusses the role identified for a segment of neural crest is in regulating the morphogenesis of the heart and associated great vessels. The paradox is that their derivatives constitute a small proportion of cells to the cardiovascular system. Findings supporting that these cells impact early cardiac function raises the interesting possibility that they indirectly control cardiovascular development at least partially through regulating function. Making connections between insults to the neural crest, cardiac function, and morphogenesis is more approachable with technological advances. Expanding our understanding of early functional consequences could be useful in improving diagnosis and testing therapies. PMID:25220155

The role of aquaporins in the anti-glioblastoma capacity of the cold plasma-stimulated medium

NASA Astrophysics Data System (ADS)

Yan, Dayun; Xiao, Haijie; Zhu, Wei; Nourmohammadi, Niki; Zhang, Lijie Grace; Bian, Ka; Keidar, Michael

2017-02-01

The cold atmospheric plasma (CAP) is a promising novel anti-cancer method. Our previous study showed that the cold plasma-stimulated medium (PSM) exerted remarkable anti-cancer effect as effectively as the direct CAP treatment did. H2O2 has been identified as a key anti-cancer substance in PSM. However, the mechanisms underlying intracellular H2O2 regulation by cancer cells is largely unknown. Aquaporins (AQPs) are the confirmed membrane channels of H2O2. In this study, we first demonstrated that the anti-glioblastoma capacity of PSM could be inhibited by silencing the expression of AQP8 in glioblastoma cells (U87MG) or using the aquaporins-blocker silver atoms. This discovery illustrates the key intermediate role of AQPs in the toxicity of PSM on cancer cells. Because the expression of AQPs varies significantly among different cancer cell lines, this study may facilitate the understanding on the diverse responses of cancer cells to PSM or the direct CAP treatment.

Tissue Factor-Factor VII Complex As a Key Regulator of Ovarian Cancer Phenotypes.

PubMed

Koizume, Shiro; Miyagi, Yohei

2015-01-01

Tissue factor (TF) is an integral membrane protein widely expressed in normal human cells. Blood coagulation factor VII (fVII) is a key enzyme in the extrinsic coagulation cascade that is predominantly secreted by hepatocytes and released into the bloodstream. The TF-fVII complex is aberrantly expressed on the surface of cancer cells, including ovarian cancer cells. This procoagulant complex can initiate intracellular signaling mechanisms, resulting in malignant phenotypes. Cancer tissues are chronically exposed to hypoxia. TF and fVII can be induced in response to hypoxia in ovarian cancer cells at the gene expression level, leading to the autonomous production of the TF-fVII complex. Here, we discuss the roles of the TF-fVII complex in the induction of malignant phenotypes in ovarian cancer cells. The hypoxic nature of ovarian cancer tissues and the roles of TF expression in endometriosis are discussed. Arguments will be extended to potential strategies to treat ovarian cancers based on our current knowledge of TF-fVII function.

The role of stromal cells in the persistence of chronic inflammation

PubMed Central

Naylor, A J; Filer, A; Buckley, C D

2013-01-01

Inflammation is an unstable state; it either resolves or persists. Inflammatory reactions often have a propensity for specific anatomical sites. Why inflammation persists with specific tissue tropism remains obscure. Increasing evidence suggests that stromal cells which define tissue architecture are the key cells involved, and therefore make attractive therapeutic targets. Research on stromal cells in general and fibroblasts in particular has so far been hampered by a lack of fibroblast-specific cell markers. This review highlights our increasing understanding of the role of fibroblasts in inflammation, and suggests that these cells provide the cellular basis for site specific chronic inflammation. PMID:23199320

The T-cell-specific adapter protein family: TSAd, ALX, and SH2D4A/SH2D4B.

PubMed

Lapinski, Philip E; Oliver, Jennifer A; Bodie, Jennifer N; Marti, Francesc; King, Philip D

2009-11-01

Adapter proteins play key roles in intracellular signal transduction through complex formation with catalytically active signaling molecules. In T lymphocytes, the role of several different types of adapter proteins in T-cell antigen receptor signal transduction is well established. An exception to this is the family of T-cell-specific adapter (TSAd) proteins comprising of TSAd, adapter protein of unknown function (ALX), SH2D4A, and SH2D4B. Only recently has the function of these adapters in T-cell signal transduction been explored. Here, we discuss advances in our understanding of the role of this family of adapter proteins in T cells. Their function as regulators of signal transduction in other cell types is also discussed.

Inactivation of YAP oncoprotein by the Hippo pathway is involved in cell contact inhibition and tissue growth control

PubMed Central

Zhao, Bin; Wei, Xiaomu; Li, Weiquan; Udan, Ryan S.; Yang, Qian; Kim, Joungmok; Xie, Joe; Ikenoue, Tsuneo; Yu, Jindan; Li, Li; Zheng, Pan; Ye, Keqiang; Chinnaiyan, Arul; Halder, Georg; Lai, Zhi-Chun; Guan, Kun-Liang

2007-01-01

The Hippo pathway plays a key role in organ size control by regulating cell proliferation and apoptosis in Drosophila. Although recent genetic studies have shown that the Hippo pathway is regulated by the NF2 and Fat tumor suppressors, the physiological regulations of this pathway are unknown. Here we show that in mammalian cells, the transcription coactivator YAP (Yes-associated protein), is inhibited by cell density via the Hippo pathway. Phosphorylation by the Lats tumor suppressor kinase leads to cytoplasmic translocation and inactivation of the YAP oncoprotein. Furthermore, attenuation of this phosphorylation of YAP or Yorkie (Yki), the Drosophila homolog of YAP, potentiates their growth-promoting function in vivo. Moreover, YAP overexpression regulates gene expression in a manner opposite to cell density, and is able to overcome cell contact inhibition. Inhibition of YAP function restores contact inhibition in a human cancer cell line bearing deletion of Salvador (Sav), a Hippo pathway component. Interestingly, we observed that YAP protein is elevated and nuclear localized in some human liver and prostate cancers. Our observations demonstrate that YAP plays a key role in the Hippo pathway to control cell proliferation in response to cell contact. PMID:17974916

The Hippo signaling pathway in stem cell biology and cancer

PubMed Central

Mo, Jung-Soon; Park, Hyun Woo; Guan, Kun-Liang

2014-01-01

The Hippo signaling pathway, consisting of a highly conserved kinase cascade (MST and Lats) and downstream transcription coactivators (YAP and TAZ), plays a key role in tissue homeostasis and organ size control by regulating tissue-specific stem cells. Moreover, this pathway plays a prominent role in tissue repair and regeneration. Dysregulation of the Hippo pathway is associated with cancer development. Recent studies have revealed a complex network of upstream inputs, including cell density, mechanical sensation, and G-protein-coupled receptor (GPCR) signaling, that modulate Hippo pathway activity. This review focuses on the role of the Hippo pathway in stem cell biology and its potential implications in tissue homeostasis and cancer. PMID:24825474

A Novel and Multivalent Role of Pax6 in Cerebellar Development

PubMed Central

Yeung, Joanna; Ha, Thomas J.; Swanson, Douglas J.

2016-01-01

Pax6 is a prominent gene in brain development. The deletion of Pax6 results in devastated development of eye, olfactory bulb, and cortex. However, it has been reported that the Pax6-null Sey cerebellum only has minor defects involving granule cells despite Pax6 being expressed throughout cerebellar development. The present work has uncovered a requirement of Pax6 in the development of all rhombic lip (RL) lineages. A significant downregulation of Tbr1 and Tbr2 expression is found in the Sey cerebellum, these are cell-specific markers of cerebellar nuclear (CN) neurons and unipolar brush cells (UBCs), respectively. The examination of Tbr1 and Lmx1a immunolabeling and Nissl staining confirmed the loss of CN neurons from the Sey cerebellum. CN neuron progenitors are produced in the mutant but there is an enhanced death of these neurons as shown by increased presence of caspase-3-positive cells. These data indicate that Pax6 regulates the survival of CN neuron progenitors. Furthermore, the analysis of experimental mouse chimeras suggests a cell-extrinsic role of Pax6 in CN neuron survival. For UBCs, using Tbr2 immunolabeling, these cells are significantly reduced in the Sey cerebellum. The loss of UBCs in the mutant is due partly to cell death in the RL and also to the reduced production of progenitors from the RL. These results demonstrate a critical role for Pax6 in regulating the generation and survival of UBCs. This and previous work from our laboratory demonstrate a seminal role of Pax6 in the development of all cerebellar glutamatergic neurons. SIGNIFICANCE STATEMENT Pax6 is a key molecule in development. Pax6 is best known as the master control gene in eye development with mutations causing aniridia in humans. Pax6 also plays important developmental roles in the cortex and olfactory bulb. During cerebellar development, Pax6 is robustly expressed in the germinal zone of all glutamatergic neurons [cerebellar nuclear (CN) neurons, granule cells, and unipolar brush cells (UBCs)]. Past work has not found abnormalities in the CN and UBC populations. Our study reveals that the Pax6-null mutation dramatically affects these cells and identifies Pax6 as a key regulator of cell survival in CN neurons and of cell production in UBCs. The present study shows how Pax6 is key to the development of glutamatergic cells in the cerebellum. PMID:27581449

Targeting inflammation in pancreatic cancer: Clinical translation

PubMed Central

Steele, Colin William; Kaur Gill, Nina Angharad; Jamieson, Nigel Balfour; Carter, Christopher Ross

2016-01-01

Preclinical modelling studies are beginning to aid development of therapies targeted against key regulators of pancreatic cancer progression. Pancreatic cancer is an aggressive, stromally-rich tumor, from which few people survive. Within the tumor microenvironment cellular and extracellular components exist, shielding tumor cells from immune cell clearance, and chemotherapy, enhancing progression of the disease. The cellular component of this microenvironment consists mainly of stellate cells and inflammatory cells. New findings suggest that manipulation of the cellular component of the tumor microenvironment is possible to promote immune cell killing of tumor cells. Here we explore possible immunogenic therapeutic strategies. Additionally extracellular stromal elements play a key role in protecting tumor cells from chemotherapies targeted at the pancreas. We describe the experimental findings and the pitfalls associated with translation of stromally targeted therapies to clinical trial. Finally, we discuss the key inflammatory signal transducers activated subsequent to driver mutations in oncogenic Kras in pancreatic cancer. We present the preclinical findings that have led to successful early trials of STAT3 inhibitors in pancreatic adenocarcinoma. PMID:27096033

Leptin receptor signaling in T cells is required for Th17 differentiation.

PubMed

Reis, Bernardo S; Lee, Kihyun; Fanok, Melania H; Mascaraque, Cristina; Amoury, Manal; Cohn, Lillian B; Rogoz, Aneta; Dallner, Olof S; Moraes-Vieira, Pedro M; Domingos, Ana I; Mucida, Daniel

2015-06-01

The hormone leptin plays a key role in energy homeostasis, and the absence of either leptin or its receptor (LepR) leads to severe obesity and metabolic disorders. To avoid indirect effects and to address the cell-intrinsic role of leptin signaling in the immune system, we conditionally targeted LepR in T cells. In contrast with pleiotropic immune disorders reported in obese mice with leptin or LepR deficiency, we found that LepR deficiency in CD4(+) T cells resulted in a selective defect in both autoimmune and protective Th17 responses. Reduced capacity for differentiation toward a Th17 phenotype by lepr-deficient T cells was attributed to reduced activation of the STAT3 and its downstream targets. This study establishes cell-intrinsic roles for LepR signaling in the immune system and suggests that leptin signaling during T cell differentiation plays a crucial role in T cell peripheral effector function. Copyright © 2015 by The American Association of Immunologists, Inc.

Scientific and Regulatory Policy Committee (SRPC) Review: Interpretation and Use of Cell Proliferation Data in Cancer Risk Assessment

EPA Science Inventory

Increased cell proliferation is a defining feature of carcinogenesis and a central key event in the mode of action for many non-genotoxic carcinogens. Quantitative cell proliferation data thus play an important role in the safety assessment of many pharmaceutical and environment...

Immune-Stimulating Combinatorial Therapy for Prostate Cancer

DTIC Science & Technology

2016-10-01

infiltration. 2. Complementary to the studies in 1, we will sort myeloid, lymphoid and cancer cells from freshly dissociated tumors in cases where enough...MION) hyperthermia and external beam radiation therapy; and, 2) developed methodologies that will be used to elucidate the role of key immune cell ...radiation therapy, immunotherapy, prostate cancer, magnetic nanoparticle(s), abscopal effect, immune cells , tumor-infiltrating immune cells , T- cells , CD4

Apoptosis in lung injury and remodeling.

PubMed

Li, Xiaopeng; Shu, Ruijie; Filippatos, Gerasimos; Uhal, Bruce D

2004-10-01

The mode of cell death termed apoptosis, sometimes referred to as programmed cell death, is as critical a determinant of cell population size as is cell proliferation. Although best characterized in cells of the immune system, apoptosis is now known to be a key factor in the maintenance of normal cell turnover within structural cells in the parenchyma of virtually every organ. Recent interest in apoptosis in the lung has sparked a surge of investigations designed to determine the roles of apoptosis in lung development, injury, and remodeling. Of particular recent interest are the roles of apoptosis in disease pathogenesis and resolution, in which the concept of apoptosis as a "programmed" cell death, i.e., genetically determined, is often more accurately viewed as "inappropriate cell suicide" with regard to its extent and/or timing. Data accumulating over the past decade have made clear the complexity of the control of lung cell apoptosis; concepts of the regulation of apoptosis originally determined in classical cell culture models are often, but not always, applicable to structural cells. For this reason, each of the many cell types of the lung must be studied as a potentially new subject with its own idiosyncrasies yet to be discovered. In light of the large volume of literature now available, this article focuses on the roles of apoptosis in three pathophysiological contexts: acute respiratory distress syndrome, chronic obstructive pulmonary disease, and pulmonary fibrosis. Each section presents key data describing the evidence for apoptosis in the lung, its possible relevance to disease pathogenesis, and proposed mechanisms that might suggest potential avenues for therapeutic intervention.

Functional and Biomimetic Materials for Engineering of the Three-Dimensional Cell Microenvironment.

PubMed

Huang, Guoyou; Li, Fei; Zhao, Xin; Ma, Yufei; Li, Yuhui; Lin, Min; Jin, Guorui; Lu, Tian Jian; Genin, Guy M; Xu, Feng

2017-10-25

The cell microenvironment has emerged as a key determinant of cell behavior and function in development, physiology, and pathophysiology. The extracellular matrix (ECM) within the cell microenvironment serves not only as a structural foundation for cells but also as a source of three-dimensional (3D) biochemical and biophysical cues that trigger and regulate cell behaviors. Increasing evidence suggests that the 3D character of the microenvironment is required for development of many critical cell responses observed in vivo, fueling a surge in the development of functional and biomimetic materials for engineering the 3D cell microenvironment. Progress in the design of such materials has improved control of cell behaviors in 3D and advanced the fields of tissue regeneration, in vitro tissue models, large-scale cell differentiation, immunotherapy, and gene therapy. However, the field is still in its infancy, and discoveries about the nature of cell-microenvironment interactions continue to overturn much early progress in the field. Key challenges continue to be dissecting the roles of chemistry, structure, mechanics, and electrophysiology in the cell microenvironment, and understanding and harnessing the roles of periodicity and drift in these factors. This review encapsulates where recent advances appear to leave the ever-shifting state of the art, and it highlights areas in which substantial potential and uncertainty remain.

Functional hierarchy of the N-terminal tyrosines of SLP-76.

PubMed

Jordan, Martha S; Sadler, Jeffrey; Austin, Jessica E; Finkelstein, Lisa D; Singer, Andrew L; Schwartzberg, Pamela L; Koretzky, Gary A

2006-02-15

The adaptor protein Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) plays a central role in T cell activation and T cell development. SLP-76 has three functional modules: an acidic domain with three key tyrosines, a central proline-rich domain, and a C-terminal Src homology 2 domain. Of these, mutation of the three N-terminal tyrosines (Y112, Y128, and Y145) results in the most profound effects on T cell development and function. Y112 and Y128 associate with Vav and Nck, two proteins shown to be important for TCR-induced phosphorylation of proximal signaling substrates, Ca(2+) flux, and actin reorganization. Y145 has been shown to be important for optimal association of SLP-76 with inducible tyrosine kinase, a key regulator of T cell function. To investigate further the role of the phosphorylatable tyrosines of SLP-76 in TCR signaling, cell lines and primary T cells expressing SLP-76 with mutations in individual or paired tyrosine residues were analyzed. These studies show that Tyr(145) of SLP-76 is the most critical tyrosine for both T cell function in vitro and T cell development in vivo.

A HaemAtlas: characterizing gene expression in differentiated human blood cells.

PubMed

Watkins, Nicholas A; Gusnanto, Arief; de Bono, Bernard; De, Subhajyoti; Miranda-Saavedra, Diego; Hardie, Debbie L; Angenent, Will G J; Attwood, Antony P; Ellis, Peter D; Erber, Wendy; Foad, Nicola S; Garner, Stephen F; Isacke, Clare M; Jolley, Jennifer; Koch, Kerstin; Macaulay, Iain C; Morley, Sarah L; Rendon, Augusto; Rice, Kate M; Taylor, Niall; Thijssen-Timmer, Daphne C; Tijssen, Marloes R; van der Schoot, C Ellen; Wernisch, Lorenz; Winzer, Thilo; Dudbridge, Frank; Buckley, Christopher D; Langford, Cordelia F; Teichmann, Sarah; Göttgens, Berthold; Ouwehand, Willem H

2009-05-07

Hematopoiesis is a carefully controlled process that is regulated by complex networks of transcription factors that are, in part, controlled by signals resulting from ligand binding to cell-surface receptors. To further understand hematopoiesis, we have compared gene expression profiles of human erythroblasts, megakaryocytes, B cells, cytotoxic and helper T cells, natural killer cells, granulocytes, and monocytes using whole genome microarrays. A bioinformatics analysis of these data was performed focusing on transcription factors, immunoglobulin superfamily members, and lineage-specific transcripts. We observed that the numbers of lineage-specific genes varies by 2 orders of magnitude, ranging from 5 for cytotoxic T cells to 878 for granulocytes. In addition, we have identified novel coexpression patterns for key transcription factors involved in hematopoiesis (eg, GATA3-GFI1 and GATA2-KLF1). This study represents the most comprehensive analysis of gene expression in hematopoietic cells to date and has identified genes that play key roles in lineage commitment and cell function. The data, which are freely accessible, will be invaluable for future studies on hematopoiesis and the role of specific genes and will also aid the understanding of the recent genome-wide association studies.

A HaemAtlas: characterizing gene expression in differentiated human blood cells

PubMed Central

Gusnanto, Arief; de Bono, Bernard; De, Subhajyoti; Miranda-Saavedra, Diego; Hardie, Debbie L.; Angenent, Will G. J.; Attwood, Antony P.; Ellis, Peter D.; Erber, Wendy; Foad, Nicola S.; Garner, Stephen F.; Isacke, Clare M.; Jolley, Jennifer; Koch, Kerstin; Macaulay, Iain C.; Morley, Sarah L.; Rendon, Augusto; Rice, Kate M.; Taylor, Niall; Thijssen-Timmer, Daphne C.; Tijssen, Marloes R.; van der Schoot, C. Ellen; Wernisch, Lorenz; Winzer, Thilo; Dudbridge, Frank; Buckley, Christopher D.; Langford, Cordelia F.; Teichmann, Sarah; Göttgens, Berthold; Ouwehand, Willem H.

2009-01-01

Hematopoiesis is a carefully controlled process that is regulated by complex networks of transcription factors that are, in part, controlled by signals resulting from ligand binding to cell-surface receptors. To further understand hematopoiesis, we have compared gene expression profiles of human erythroblasts, megakaryocytes, B cells, cytotoxic and helper T cells, natural killer cells, granulocytes, and monocytes using whole genome microarrays. A bioinformatics analysis of these data was performed focusing on transcription factors, immunoglobulin superfamily members, and lineage-specific transcripts. We observed that the numbers of lineage-specific genes varies by 2 orders of magnitude, ranging from 5 for cytotoxic T cells to 878 for granulocytes. In addition, we have identified novel coexpression patterns for key transcription factors involved in hematopoiesis (eg, GATA3-GFI1 and GATA2-KLF1). This study represents the most comprehensive analysis of gene expression in hematopoietic cells to date and has identified genes that play key roles in lineage commitment and cell function. The data, which are freely accessible, will be invaluable for future studies on hematopoiesis and the role of specific genes and will also aid the understanding of the recent genome-wide association studies. PMID:19228925

Reverse engineering of TLX oncogenic transcriptional networks identifies RUNX1 as tumor suppressor in T-ALL.

PubMed

Della Gatta, Giusy; Palomero, Teresa; Perez-Garcia, Arianne; Ambesi-Impiombato, Alberto; Bansal, Mukesh; Carpenter, Zachary W; De Keersmaecker, Kim; Sole, Xavier; Xu, Luyao; Paietta, Elisabeth; Racevskis, Janis; Wiernik, Peter H; Rowe, Jacob M; Meijerink, Jules P; Califano, Andrea; Ferrando, Adolfo A

2012-02-26

The TLX1 and TLX3 transcription factor oncogenes have a key role in the pathogenesis of T cell acute lymphoblastic leukemia (T-ALL). Here we used reverse engineering of global transcriptional networks to decipher the oncogenic regulatory circuit controlled by TLX1 and TLX3. This systems biology analysis defined T cell leukemia homeobox 1 (TLX1) and TLX3 as master regulators of an oncogenic transcriptional circuit governing T-ALL. Notably, a network structure analysis of this hierarchical network identified RUNX1 as a key mediator of the T-ALL induced by TLX1 and TLX3 and predicted a tumor-suppressor role for RUNX1 in T cell transformation. Consistent with these results, we identified recurrent somatic loss-of-function mutations in RUNX1 in human T-ALL. Overall, these results place TLX1 and TLX3 at the top of an oncogenic transcriptional network controlling leukemia development, show the power of network analyses to identify key elements in the regulatory circuits governing human cancer and identify RUNX1 as a tumor-suppressor gene in T-ALL.

Insights into the key roles of proteoglycans in breast cancer biology and translational medicine

PubMed Central

Theocharis, Achilleas D.; Skandalis, Spyros S.; Neill, Thomas; Multhaupt, Hinke A. B.; Hubo, Mario; Frey, Helena; Gopal, Sandeep; Gomes, Angélica; Afratis, Nikos; Lim, Hooi Ching; Couchman, John R.; Filmus, Jorge; Sanderson, Ralph D.; Schaefer, Liliana; Iozzo, Renato V.; Karamanos, Nikos K.

2015-01-01

Proteoglycans control numerous normal and pathological processes, among which are morphogenesis, tissue repair, inflammation, vascularization and cancer metastasis. During tumor development and growth, proteoglycan expression is markedly modified in the tumor microenvironment. Altered expression of proteoglycans on tumor and stromal cell membranes affects cancer cell signaling, growth and survival, cell adhesion, migration and angiogenesis. Despite the high complexity and heterogeneity of breast cancer, the rapid evolution in our knowledge that proteoglycans are among the key players in the breast tumor microenvironment suggests their potential as pharmacological targets in this type of cancer. It has been recently suggested that pharmacological treatment may target proteoglycan metabolism, their utilization as targets for immunotherapy or their direct use as therapeutic agents. The diversity inherent in the proteoglycans that will be presented herein provides the potential for multiple layers of regulation of breast tumor behavior. This review summarizes recent developments concerning the biology of selected proteoglycans in breast cancer, and presents potential targeted therapeutic approaches based on their novel key roles in breast cancer. PMID:25829250

Pivotal roles of Kupffer cells in the progression and regression of DDC-induced chronic cholangiopathy.

PubMed

Jemail, Leila; Miyao, Masashi; Kotani, Hirokazu; Kawai, Chihiro; Minami, Hirozo; Abiru, Hitoshi; Tamaki, Keiji

2018-04-23

Kupffer cells (KCs) are key players in maintaining tissue homeostasis and are involved in various liver diseases. However, the roles of KCs in the pathogenesis of cholangiopathy are largely unknown. We aimed to investigate the precise roles of KCs in both the progression and regression phases of the 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-induced cholangiopathy model. In the early phase of DDC-induced cholangiopathy, the number of KCs significantly increased over time. Moreover, KCs were associated with abnormal phenotypic changes in other liver cells, such as hepatocytes, biliary epithelial cells, liver sinusoidal endothelial cells, and hepatic stellate cells. In contrast, KC depletion by clodronate administration suppressed the progression of the disease, and maintained the phenotypes of other cells. In the regression phase, the numbers of KCs significantly decreased, and the cells redifferentiated to their quiescent state. In contrast, KC depletion delayed the recovery of cells by maintaining other liver cells in an active state. These findings suggest that KCs play detrimental roles in the progression phase; however, they are beneficial in the regression phase by mediating interactions between other liver cells. Our data provide new insights into the roles of KCs in the pathogenesis of cholangiopathy.

Hallmarks of glycosylation in cancer.

PubMed

Munkley, Jennifer; Elliott, David J

2016-06-07

Aberrant glycosylation plays a fundamental role in key pathological steps of tumour development and progression. Glycans have roles in cancer cell signalling, tumour cell dissociation and invasion, cell-matrix interactions, angiogenesis, metastasis and immune modulation. Aberrant glycosylation is often cited as a 'hallmark of cancer' but is notably absent from both the original hallmarks of cancer and from the next generation of emerging hallmarks. This review discusses how glycosylation is clearly an enabling characteristic that is causally associated with the acquisition of all the hallmark capabilities. Rather than aberrant glycosylation being itself a hallmark of cancer, another perspective is that glycans play a role in every recognised cancer hallmark.

Hallmarks of glycosylation in cancer

PubMed Central

Munkley, Jennifer; Elliott, David J.

2016-01-01

Aberrant glycosylation plays a fundamental role in key pathological steps of tumour development and progression. Glycans have roles in cancer cell signalling, tumour cell dissociation and invasion, cell-matrix interactions, angiogenesis, metastasis and immune modulation. Aberrant glycosylation is often cited as a ‘hallmark of cancer’ but is notably absent from both the original hallmarks of cancer and from the next generation of emerging hallmarks. This review discusses how glycosylation is clearly an enabling characteristic that is causally associated with the acquisition of all the hallmark capabilities. Rather than aberrant glycosylation being itself a hallmark of cancer, another perspective is that glycans play a role in every recognised cancer hallmark. PMID:27007155

A novel adoptive transfer model of chronic lymphocytic leukemia suggests a key role for T lymphocytes in the disease

PubMed Central

Bagnara, Davide; Kaufman, Matthew S.; Calissano, Carlo; Marsilio, Sonia; Patten, Piers E. M.; Simone, Rita; Chum, Philip; Yan, Xiao-Jie; Allen, Steven L.; Kolitz, Jonathan E.; Baskar, Sivasubramanian; Rader, Christoph; Mellstedt, Hakan; Rabbani, Hodjattallah; Lee, Annette; Gregersen, Peter K.; Rai, Kanti R.

2011-01-01

Chronic lymphocytic leukemia (CLL) is an incurable adult disease of unknown etiology. Understanding the biology of CLL cells, particularly cell maturation and growth in vivo, has been impeded by lack of a reproducible adoptive transfer model. We report a simple, reproducible system in which primary CLL cells proliferate in nonobese diabetes/severe combined immunodeficiency/γcnull mice under the influence of activated CLL-derived T lymphocytes. By cotransferring autologous T lymphocytes, activated in vivo by alloantigens, the survival and growth of primary CFSE-labeled CLL cells in vivo is achieved and quantified. Using this approach, we have identified key roles for CD4+ T cells in CLL expansion, a direct link between CD38 expression by leukemic B cells and their activation, and support for CLL cells preferentially proliferating in secondary lymphoid tissues. The model should simplify analyzing kinetics of CLL cells in vivo, deciphering involvement of nonleukemic elements and nongenetic factors promoting CLL cell growth, identifying and characterizing potential leukemic stem cells, and permitting preclinical studies of novel therapeutics. Because autologous activated T lymphocytes are 2-edged swords, generating unwanted graph-versus-host and possibly autologous antitumor reactions, the model may also facilitate analyses of T-cell populations involved in immune surveillance relevant to hematopoietic transplantation and tumor cytoxicity. PMID:21385850

Numerical analysis of a red blood cell flowing through a thin micropore.

PubMed

Omori, Toshihiro; Hosaka, Haruki; Imai, Yohsuke; Yamaguchi, Takami; Ishikawa, Takuji

2014-01-01

Red blood cell (RBC) deformability plays a key role in microcirculation, especially in vessels that have diameters even smaller than the nominal cell size. In this study, we numerically investigate the dynamics of an RBC in a thin micropore. The RBC is modeled as a capsule with a thin hyperelastic membrane. In a numerical simulation, we employ a boundary element method for fluid mechanics and a finite element method for membrane mechanics. The resulting RBC deformation towards the flow direction is suppressed considerably by increased cytoplasm viscosity, whereas the gap between the cell membrane and solid wall becomes smaller with higher cytoplasm viscosity. We also measure the transit time of the RBC and find that nondimensional transit time increases nonlinearly with respect to the viscosity ratio, whereas it is invariant to the capillary number. In conclusion, cytoplasmic viscosity plays a key role in the dynamics of an RBC in a thin pore. The results of this study will be useful for designing a microfluidic device to measure cytoplasmic viscosity.

Bruton's Tyrosine Kinase: An Emerging Key Player in Innate Immunity.

PubMed

Weber, Alexander N R; Bittner, Zsofia; Liu, Xiao; Dang, Truong-Minh; Radsak, Markus Philipp; Brunner, Cornelia

2017-01-01

Bruton's tyrosine kinase (BTK) was initially discovered as a critical mediator of B cell receptor signaling in the development and functioning of adaptive immunity. Growing evidence also suggests multiple roles for BTK in mononuclear cells of the innate immune system, especially in dendritic cells and macrophages. For example, BTK has been shown to function in Toll-like receptor-mediated recognition of infectious agents, cellular maturation and recruitment processes, and Fc receptor signaling. Most recently, BTK was additionally identified as a direct regulator of a key innate inflammatory machinery, the NLRP3 inflammasome. BTK has thus attracted interest not only for gaining a more thorough basic understanding of the human innate immune system but also as a target to therapeutically modulate innate immunity. We here review the latest developments on the role of BTK in mononuclear innate immune cells in mouse versus man, with specific emphasis on the sensing of infectious agents and the induction of inflammation. Therapeutic implications for modulating innate immunity and critical open questions are also discussed.

Circadian clock gene plays a key role on ovarian cycle and spontaneous abortion.

PubMed

Li, Ruiwen; Cheng, Shuting; Wang, Zhengrong

2015-01-01

Circadian locomotor output cycles protein kaput (CLOCK) plays a key role in maintaining circadian rhythms and activation of downstream elements. However, its function on human female reproductive system remains unknown. To investigate the potential role of CLOCK, CLOCK-shRNAs were transfected into mouse 129 ES cells or injected into the ovaries of adult female mice. Western blotting was utilized to analyze the protein interactions and flow cytometry was used to assess apoptosis. The expression of CLOCK peaked at the 6th week in the healthy fetuses. However, an abnormal expression of CLOCK was detected in fetuses from spontaneous miscarriage. To determine the effect of CLOCK on female fertility, a small hairpin RNA (shRNA) strategy was used to specifically knockdown the CLOCK gene expression in vitro and in vivo. Knockdown of CLOCK induced apoptosis in mouse embryonic stem (mES) cells and inhibited the proliferation in mES cells in vitro. CLOCK knockdown also led to decreased release of oocytes and smaller litter size compared with control in vivo. Collectively, theses findings indicate that CLOCK plays an important role in fertility and that the CLOCK knockdown leads to reduction in reproduction and increased miscarriage risk. © 2015 S. Karger AG, Basel.

The multi-dimensional roles of astrocytes in ALS.

PubMed

Yamanaka, Koji; Komine, Okiru

2018-01-01

Despite significant progress in understanding the molecular and genetic aspects of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease characterized by the progressive loss of motor neurons, the precise and comprehensive pathomechanisms remain largely unknown. In addition to motor neuron involvement, recent studies using cellular and animal models of ALS indicate that there is a complex interplay between motor neurons and neighboring non-neuronal cells, such as astrocytes, in non-cell autonomous neurodegeneration. Astrocytes are key homeostatic cells that play numerous supportive roles in maintaining the brain environment. In neurodegenerative diseases such as ALS, astrocytes change their shape and molecular expression patterns and are referred to as reactive or activated astrocytes. Reactive astrocytes in ALS lose their beneficial functions and gain detrimental roles. In addition, interactions between motor neurons and astrocytes are impaired in ALS. In this review, we summarize growing evidence that astrocytes are critically involved in the survival and demise of motor neurons through several key molecules and cascades in astrocytes in both sporadic and inherited ALS. These observations strongly suggest that astrocytes have multi-dimensional roles in disease and are a viable therapeutic target for ALS. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

[The role of endothelial cells and endothelial precursor cells in angiogenesis].

PubMed

Poreba, Małgorzata; Usnarska-Zubkiewicz, Lidia; Kuliczkowski, Kazimierz

2006-01-01

Endothelium plays a key role in maintenance of vascular homeostasis in human organism. According to new data endothelial cells and hematopoietic cells have a common precursor in prenatal life--a hemangioblast, which explains the fact of sharing the same determinants on the surface of both type of cells. Circulating endothelial precursors were identified in adults and this suggests that hemangioblasts may be present not only during embriogenesis. In some clinical situations the increased numbers of endothelial cells and endothelial precursors were noted, and especially in patients with neoplastic diseases, which is probably the result of increased angiogenesis. Endothelial precursors are thought to be the promice for therapeutic purposes in future--to increase local angiogenesis.

[Genetic regulation of plant shoot stem cells].

PubMed

Al'bert, E V; Ezhova, T A

2013-02-01

This article describes the main features of plant stem cells and summarizes the results of studies of the genetic control of stem cell maintenance in the apical meristem of the shoot. It is demonstrated that the WUS-CLV gene system plays a key role in the maintenance of shoot apical stem cells and the formation of adventitious buds and somatic embryos. Unconventional concepts of plant stem cells are considered.

miR-150 Regulates Memory CD8 T Cell Differentiation via c-Myb.

PubMed

Chen, Zeyu; Stelekati, Erietta; Kurachi, Makoto; Yu, Sixiang; Cai, Zhangying; Manne, Sasikanth; Khan, Omar; Yang, Xiaolu; Wherry, E John

2017-09-12

MicroRNAs play an important role in T cell responses. However, how microRNAs regulate CD8 T cell memory remains poorly defined. Here, we found that miR-150 negatively regulates CD8 T cell memory in vivo. Genetic deletion of miR-150 disrupted the balance between memory precursor and terminal effector CD8 T cells following acute viral infection. Moreover, miR-150-deficient memory CD8 T cells were more protective upon rechallenge. A key circuit whereby miR-150 repressed memory CD8 T cell development through the transcription factor c-Myb was identified. Without miR-150, c-Myb was upregulated and anti-apoptotic targets of c-Myb, such as Bcl-2 and Bcl-xL, were also increased, suggesting a miR-150-c-Myb survival circuit during memory CD8 T cell development. Indeed, overexpression of non-repressible c-Myb rescued the memory CD8 T cell defects caused by overexpression of miR-150. Overall, these results identify a key role for miR-150 in memory CD8 T cells through a c-Myb-controlled enhanced survival circuit. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Elsevier Trophoblast Research Award Lecture: Unique properties of decidual T cells and their role in immune regulation during human pregnancy.

PubMed

Tilburgs, T; Claas, F H J; Scherjon, S A

2010-03-01

Maternal lymphocytes at the fetal-maternal interface play a key role in the immune acceptance of the allogeneic fetus. Most studies focus on decidual NK cells and their interaction with fetal trophoblasts, whereas limited data are available on the mechanisms of fetus specific immune recognition and immune regulation by decidual T cells at the fetal-maternal interface. The aim of this review is to describe the phenotypic characteristics of decidual T cell subsets present at the fetal-maternal interface, their interaction with HLA-C expressed by fetal trophoblasts and their role in immune recognition and regulation at the fetal-maternal interface during human pregnancy. Copyright 2010 Elsevier Ltd. All rights reserved.

Arginine Methylation: The Coming of Age.

PubMed

Blanc, Roméo S; Richard, Stéphane

2017-01-05

Arginine methylation is a common post-translational modification functioning as an epigenetic regulator of transcription and playing key roles in pre-mRNA splicing, DNA damage signaling, mRNA translation, cell signaling, and cell fate decision. Recently, a wealth of studies using transgenic mouse models and selective PRMT inhibitors helped define physiological roles for protein arginine methyltransferases (PRMTs) linking them to diseases such as cancer and metabolic, neurodegenerative, and muscular disorders. This review describes the recent molecular advances that have been uncovered in normal and diseased mammalian cells. Copyright © 2017 Elsevier Inc. All rights reserved.

c-Myc plays a key role in TADs-induced apoptosis and cell cycle arrest in human hepatocellular carcinoma cells

PubMed Central

Zhang, Dongdong; Qi, Junpeng; Liu, Rui; Dai, Bingling; Ma, Weina; Zhan, Yingzhuan; Zhang, Yanmin

2015-01-01

Cancer cell growth is complicated progression which is regulated and controlled by multiple factors including cell cycle, migration and apoptosis. In present study, we report that TADs, a novel derivative of taspine, has an essential role in resisting hepatocellular carcinoma growth (including arrest cell cycle) and migration, and inducing cell apoptosis. Our findings demonstrated that the TADs showed good inhibition on the hepatoma cell growth and migration, and good action on apoptosis induction. Using genome-wide microarray analysis, we found the down-regulated growth and apoptosis factors, and selected down-regulated genes were confirmed by Western blot. Knockdown of a checkpoint c-Myc by siRNA significantly attenuated tumor inhibition and apoptosis effects of TADs. Moreover, our results indicated TADs could simultaneously increase cyclin D1 protein levels and decrease amount of cyclin E, cyclin B1 and cdc2 of the cycle proteins, and also TADs reduced Bcl-2 expression, and upregulated Bad, Bak and Bax activities. In conclusion, these results illustrated that TADs is a key factor in growth and apoptosis signaling inhibitor, has potential in cancer therapy. PMID:26045987

The future is now: single-cell genomics of bacteria and archaea

PubMed Central

Blainey, Paul C.

2013-01-01

Interest in the expanding catalog of uncultivated microorganisms, increasing recognition of heterogeneity among seemingly similar cells, and technological advances in whole-genome amplification and single-cell manipulation are driving considerable progress in single-cell genomics. Here, the spectrum of applications for single-cell genomics, key advances in the development of the field, and emerging methodology for single-cell genome sequencing are reviewed by example with attention to the diversity of approaches and their unique characteristics. Experimental strategies transcending specific methodologies are identified and organized as a road map for future studies in single-cell genomics of environmental microorganisms. Over the next decade, increasingly powerful tools for single-cell genome sequencing and analysis will play key roles in accessing the genomes of uncultivated organisms, determining the basis of microbial community functions, and fundamental aspects of microbial population biology. PMID:23298390

Cancer metabolism and the Warburg effect: the role of HIF-1 and PI3K.

PubMed

Courtnay, Rupert; Ngo, Darleen C; Malik, Neha; Ververis, Katherine; Tortorella, Stephanie M; Karagiannis, Tom C

2015-04-01

Cancer cells have been shown to have altered metabolism when compared to normal non-malignant cells. The Warburg effect describes a phenomenon in which cancer cells preferentially metabolize glucose by glycolysis, producing lactate as an end product, despite being the presence of oxygen. The phenomenon was first described by Otto Warburg in the 1920s, and has resurfaced as a controversial theory, with both supportive and opposing arguments. The biochemical aspects of the Warburg effect outline a strong explanation for the cause of cancer cell proliferation, by providing the biological requirements for a cell to grow. Studies have shown that pathways such as phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) as well as hypoxia inducible factor-1 (HIF-1) are central regulators of glycolysis, cancer metabolism and cancer cell proliferation. Studies have shown that PI3K signaling pathways have a role in many cellular processes such as metabolism, inflammation, cell survival, motility and cancer progression. Herein, the cellular aspects of the PI3K pathway are described, as well as the influence HIF has on cancer cell metabolism. HIF-1 activation has been related to angiogenesis, erythropoiesis and modulation of key enzymes involved in aerobic glycolysis, thereby modulating key processes required for the Warburg effect. In this review we discuss the molecular aspects of the Warburg effect with a particular emphasis on the role of the HIF-1 and the PI3K pathway.

Microtubule actin crosslinking factor 1 promotes osteoblast differentiation by promoting β-catenin/TCF1/Runx2 signaling axis.

PubMed

Hu, Lifang; Su, Peihong; Yin, Chong; Zhang, Yan; Li, Runzhi; Yan, Kun; Chen, Zhihao; Li, Dijie; Zhang, Ge; Wang, Liping; Miao, Zhiping; Qian, Airong; Xian, Cory J

2018-02-01

Osteoblast differentiation is a multistep process delicately regulated by many factors, including cytoskeletal dynamics and signaling pathways. Microtubule actin crosslinking factor 1 (MACF1), a key cytoskeletal linker, has been shown to play key roles in signal transduction and in diverse cellular processes; however, its role in regulating osteoblast differentiation is still needed to be elucidated. To further uncover the functions and mechanisms of action of MACF1 in osteoblast differentiation, we examined effects of MACF1 knockdown (MACF1-KD) in MC3T3-E1 osteoblastic cells on their osteoblast differentiation and associated molecular mechanisms. The results showed that knockdown of MACF1 significantly suppressed mineralization of MC3T3-E1 cells, down-regulated the expression of key osteogenic genes alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2) and type I collagen α1 (Col Iα1). Knockdown of MACF1 dramatically reduced the nuclear translocation of β-catenin, decreased the transcriptional activation of T cell factor 1 (TCF1), and down-regulated the expression of TCF1, lymphoid enhancer-binding factor 1 (LEF1), and Runx2, a target gene of β-catenin/TCF1. In addition, MACF1-KD increased the active level of glycogen synthase kinase-3β (GSK-3β), which is a key regulator for β-catenin signal transduction. Moreover, the reduction of nuclear β-catenin amount and decreased expression of TCF1 and Runx2 were significantly reversed in MACF1-KD cells when treated with lithium chloride, an agonist for β-catenin by inhibiting GSK-3β activity. Taken together, these findings suggest that knockdown of MACF1 in osteoblastic cells inhibits osteoblast differentiation through suppressing the β-catenin/TCF1-Runx2 axis. Thus, a novel role of MACF1 in and a new mechanistic insight of osteoblast differentiation are uncovered. © 2017 Wiley Periodicals, Inc.

Regulation and Function of TIFAB in Myelodysplastic Syndrome

DTIC Science & Technology

2014-08-01

knockdown of TIFAB in human CD34+ hematopoietic stem /progenitor cells results in increased survival and proliferation, TIFAB inhibits TRAF6 protein...regulator of human hematopoietic cells . Our key observations show that knockdown of TIFAB in human CD34+ hematopoietic stem /progenitor cells results in...reveals an essential role of mTOR in hematopoietic stem cell engraftment and hematopoiesis. (2013). Haematologica,!98(9):!135381358.! PMID:!23716557

[The role of Th17 cells in anti-cancer immunity].

PubMed

Hus, Iwona; Maciag, Ewa; Roliński, Jacek

2010-05-25

Th17 cells are a newly identified population of CD4+ Th cells characterized by interleukin 17 production and are therefore named "Th17". Interleukin 17 (IL-17; IL-17A) is one of the key cytokines for the activation, recruitment, and migration of neutrophils, so Th17 cells have been suggested to play an important role in responses against extracellular bacteria and fungi, in which granulocyte infiltration is highly protective. Among the other cytokines secreted by Th17 cells are IL-22, IL-26, IL-6, and TNF-a. Th17 cells are considered to be involved in the pathogenesis of various inflammatory, autoimmune, and allergic diseases. Th17 cells were found in both mouse and human tumors; however, their role in the tumor microenvironment is still poorly understood IL-17, as a pleiotropic cytokine, may suppress or promote tumor growth since it was shown that it stimulated tumor growth by inducing tumor vascularization or enhancing inflammation, but some other studies revealed also opposite roles for Th17 cells in human tumors. It seems that Th17 cells may play distinct roles in cancer depending of tumor immunogenicity, the stage of development, and the impact of inflammation and angiogenesis on tumor pathogenesis.

Role of caspase-9 in the effector caspases and genome expressions, and growth of bovine skeletal myoblasts.

PubMed

Van Ba, Hoa; Hwang, Inho

2014-02-01

Caspase-9 has been reported as the key regulator of apoptosis, however, its role in skeletal myoblast development and molecular involvements during cell growth still remains unknown. The current study aimed to present the key role of caspase-9 in the expressions of apoptotic caspases and genome, and cell viability during myoblast growth using RNA interference mediated silencing. Three small interference RNA sequences (siRNAs) targeting caspase-9 gene was designed and ligated into pSilencer plasmid vector to construct shRNA expression constructs. Cells were transfected with the constructs for 48 h. Results indicated that all three siRNAs could silence the caspase-9 mRNA expression significantly. Particularly, the mRNA expression level of caspase-9 in the cells transfected by shRNA1, shRNA2 and shRNA3 constructs were reduced by 37.85%, 68.20% and 58.14%, respectively. Suppression of caspase-9 led to the significant increases in the mRNA and protein expressions of effector caspase-3, whereas the reduction in mRNA and protein expressions of caspase-7. The microarray results showed that the suppression of caspase-9 resulted in significant upregulations of cell proliferation-, adhesion-, growth-, development- and division-regulating genes, whereas the reduction in the expressions of cell death program- and stress response-regulating genes. Furthermore, cell viability was significantly increased following the transfection. These data suggest that caspase-9 could play an important role in the control of cell growth, and knockdown of caspase-9 may have genuine potential in the treatment of skeletal muscle atrophy. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

[Hyperosmolarity: Intracellular effects and implication in dry eye disease].

PubMed

Warcoin, E; Clouzeau, C; Brignole-Baudouin, F; Baudouin, C

2016-09-01

Dry eye disease is a multifactorial disease affecting the lacrimal functional unit and which has a significant impact on the quality of life of patients. This pathology works as a vicious circle at the ocular surface in which hyperosmolarity of the tear film plays a key role. This review intends to describe the different reported intracellular effects induced by hyperosmolarity in cells: alteration of cytoskeleton, cell cycle slowdown, adaptation mechanisms triggered as restoration of cell volume and accumulation of compatible osmolytes, the crucial role of the osmoprotectant factor Nuclear Factor of the Activated T cells-5 (NFAT5), apoptosis, as well as oxidative stress and inflammatory responses caused by this particular condition. Reported effects of hyperosmolarity in the experimental studies specific of dry eye disease concerning ocular surface cells will be described in parallel. Indeed, these data allow to understand a part of the pathophysiology of the disease, and specially the links between tear hyperosmolarity and inflammation of the ocular surface, the second key of the pathology phenomenon. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Erythropoietin and the use of a transgenic model of erythropoietin-deficient mice

PubMed Central

Pichon, Aurélien; Jeton, Florine; El Hasnaoui-Saadani, Raja; Hagström, Luciana; Launay, Thierry; Beaudry, Michèle; Marchant, Dominique; Quidu, Patricia; Macarlupu, Jose-Luis; Favret, Fabrice; Richalet, Jean-Paul; Voituron, Nicolas

2016-01-01

Despite its well-known role in red blood cell production, it is now accepted that erythropoietin (Epo) has other physiological functions. Epo and its receptors are expressed in many tissues, such as the brain and heart. The presence of Epo/Epo receptors in these organs suggests other roles than those usually assigned to this protein. Thus, the aim of this review is to describe the effects of Epo deficiency on adaptation to normoxic and hypoxic environments and to suggest a key role of Epo on main physiological adaptive functions. Our original model of Epo-deficient (Epo-TAgh) mice allowed us to improve our knowledge of the possible role of Epo in O2 homeostasis. The use of anemic transgenic mice revealed Epo as a crucial component of adaptation to hypoxia. Epo-TAgh mice survive well in hypoxic conditions despite low hematocrit. Furthermore, Epo plays a key role in neural control of ventilatory acclimatization and response to hypoxia, in deformability of red blood cells, in cerebral and cardiac angiogenesis, and in neuro- and cardioprotection. PMID:27800506

The Asymmetric Cell Division Regulators Par3, Scribble and Pins/Gpsm2 Are Not Essential for Erythroid Development or Enucleation

PubMed Central

Wölwer, Christina B.; Gödde, Nathan; Pase, Luke B.; Elsum, Imogen A.; Lim, Krystle Y. B.; Sacirbegovic, Faruk; Walkley, Carl R.; Ellis, Sarah; Ohno, Shigeo; Matsuzaki, Fumio; Russell, Sarah M.; Humbert, Patrick O.

2017-01-01

Erythroid enucleation is the process by which the future red blood cell disposes of its nucleus prior to entering the blood stream. This key event during red blood cell development has been likened to an asymmetric cell division (ACD), by which the enucleating erythroblast divides into two very different daughter cells of alternate molecular composition, a nucleated cell that will be removed by associated macrophages, and the reticulocyte that will mature to the definitive erythrocyte. Here we investigated gene expression of members of the Par, Scribble and Pins/Gpsm2 asymmetric cell division complexes in erythroid cells, and functionally tested their role in erythroid enucleation in vivo and ex vivo. Despite their roles in regulating ACD in other contexts, we found that these polarity regulators are not essential for erythroid enucleation, nor for erythroid development in vivo. Together our results put into question a role for cell polarity and asymmetric cell division in erythroid enucleation. PMID:28095473

A role for the ESCRT system in cell division in archaea.

PubMed

Samson, Rachel Y; Obita, Takayuki; Freund, Stefan M; Williams, Roger L; Bell, Stephen D

2008-12-12

Archaea are prokaryotic organisms that lack endomembrane structures. However, a number of hyperthermophilic members of the Kingdom Crenarchaea, including members of the Sulfolobus genus, encode homologs of the eukaryotic endosomal sorting system components Vps4 and ESCRT-III (endosomal sorting complex required for transport-III). We found that Sulfolobus ESCRT-III and Vps4 homologs underwent regulation of their expression during the cell cycle. The proteins interacted and we established the structural basis of this interaction. Furthermore, these proteins specifically localized to the mid-cell during cell division. Overexpression of a catalytically inactive mutant Vps4 in Sulfolobus resulted in the accumulation of enlarged cells, indicative of failed cell division. Thus, the archaeal ESCRT system plays a key role in cell division.

Role of Osmolytes in Regulating Immune System.

PubMed

Kumar, Tarun; Yadav, Manisha; Singh, Laishram Rajendrakumar

2016-01-01

The immune system has evolved to protect the host organism from diverse range of pathogenic microbes that are themselves constantly evolving. It is a complex network of cells, humoral factors, chemokines and cytokines. Dysregulation of immune system results in various kinds of immunological disorders. There are several external agents which govern the regulation of immune system. Recent studies have indicated the role of osmolytes in regulation of various immunological processes such as Ag-Ab interaction, Ig assembly, Ag presentation etc. In this present review, we have systematically discussed the role of osmolytes involved in regulation of several key immunological processes. Osmolytes are involved in the regulation of several key immunological processes such as immunoglobulin assembly and folding, immune cells proliferation, regulation of immune cells function, Ag-Ab interaction, antigen presentation, inflammatory response and protection against photo-immunosuppression. Hence, osmolytes and their transporters might be used as potential drug and drug targets respectively. This review is therefore designed to help clinicians in development of osmolyte based therapeutic strategies in the treatment of various immunological disorders. Appropriate future perspectives have also been included.

mTOR-Dependent Cell Proliferation in the Brain.

PubMed

Ryskalin, Larisa; Lazzeri, Gloria; Flaibani, Marina; Biagioni, Francesca; Gambardella, Stefano; Frati, Alessandro; Fornai, Francesco

2017-01-01

The mammalian Target of Rapamycin (mTOR) is a molecular complex equipped with kinase activity which controls cell viability being key in the PI3K/PTEN/Akt pathway. mTOR acts by integrating a number of environmental stimuli to regulate cell growth, proliferation, autophagy, and protein synthesis. These effects are based on the modulation of different metabolic pathways. Upregulation of mTOR associates with various pathological conditions, such as obesity, neurodegeneration, and brain tumors. This is the case of high-grade gliomas with a high propensity to proliferation and tissue invasion. Glioblastoma Multiforme (GBM) is a WHO grade IV malignant, aggressive, and lethal glioma. To date, a few treatments are available although the outcome of GBM patients remains poor. Experimental and pathological findings suggest that mTOR upregulation plays a major role in determining an aggressive phenotype, thus determining relapse and chemoresistance. Among several activities, mTOR-induced autophagy suppression is key in GBM malignancy. In this article, we discuss recent evidence about mTOR signaling and its role in normal brain development and pathological conditions, with a special emphasis on its role in GBM.

mTOR-Dependent Cell Proliferation in the Brain

PubMed Central

Lazzeri, Gloria; Frati, Alessandro

2017-01-01

The mammalian Target of Rapamycin (mTOR) is a molecular complex equipped with kinase activity which controls cell viability being key in the PI3K/PTEN/Akt pathway. mTOR acts by integrating a number of environmental stimuli to regulate cell growth, proliferation, autophagy, and protein synthesis. These effects are based on the modulation of different metabolic pathways. Upregulation of mTOR associates with various pathological conditions, such as obesity, neurodegeneration, and brain tumors. This is the case of high-grade gliomas with a high propensity to proliferation and tissue invasion. Glioblastoma Multiforme (GBM) is a WHO grade IV malignant, aggressive, and lethal glioma. To date, a few treatments are available although the outcome of GBM patients remains poor. Experimental and pathological findings suggest that mTOR upregulation plays a major role in determining an aggressive phenotype, thus determining relapse and chemoresistance. Among several activities, mTOR-induced autophagy suppression is key in GBM malignancy. In this article, we discuss recent evidence about mTOR signaling and its role in normal brain development and pathological conditions, with a special emphasis on its role in GBM. PMID:29259984

Distinct Cellular Locations of Carbonic Anhydrases Mediate Carbon Dioxide Control of Stomatal Movements1[OPEN

PubMed Central

Hu, Honghong; Rappel, Wouter-Jan; Occhipinti, Rossana; Ries, Amber; Böhmer, Maik; You, Lei; Xiao, Chuanlei; Engineer, Cawas B.; Boron, Walter F.; Schroeder, Julian I.

2015-01-01

Elevated carbon dioxide (CO2) in leaves closes stomatal apertures. Research has shown key functions of the β-carbonic anhydrases (βCA1 and βCA4) in rapid CO2-induced stomatal movements by catalytic transmission of the CO2 signal in guard cells. However, the underlying mechanisms remain unclear, because initial studies indicate that these Arabidopsis (Arabidopsis thaliana) βCAs are targeted to distinct intracellular compartments upon expression in tobacco (Nicotiana benthamiana) cells. Which cellular location of these enzymes plays a key role in native guard cells in CO2-regulated stomatal movements remains unknown. Here, we express fluorescently tagged CAs in guard cells of ca1ca4 double-mutant plants and show that the specific locations of βCA4 at the plasma membrane and βCA1 in native guard cell chloroplasts each can mediate rapid CO2 control of stomatal movements. Localization and complementation analyses using a mammalian αCAII-yellow fluorescent protein in guard cells further show that cytoplasmic localization is also sufficient to restore CO2 regulation of stomatal conductance. Mathematical modeling of cellular CO2 catalysis suggests that the dynamics of the intracellular HCO3− concentration change in guard cells can be driven by plasma membrane and cytoplasmic localizations of CAs but not as clearly by chloroplast targeting. Moreover, modeling supports the notion that the intracellular HCO3− concentration dynamics in guard cells are a key mechanism in mediating CO2-regulated stomatal movements but that an additional chloroplast role of CAs exists that has yet to be identified. PMID:26243620

Distinct Cellular Locations of Carbonic Anhydrases Mediate Carbon Dioxide Control of Stomatal Movements

DOE PAGES

Hu, Honghong; Rappel, Wouter-Jan; Occhipinti, Rossana; ...

2015-09-28

Elevated carbon dioxide (CO 2) in leaves closes stomatal apertures. Research has shown key functions of the β-carbonic anhydrases (βCA1 and βCA4) in rapid CO 2-induced stomatal movements by catalytic transmission of the CO 2 signal in guard cells. But, the underlying mechanisms remain unclear, because initial studies indicate that these Arabidopsis (Arabidopsis thaliana) βCAs are targeted to distinct intracellular compartments upon expression in tobacco (Nicotiana benthamiana) cells. Which cellular location of these enzymes plays a key role in native guard cells in CO 2-regulated stomatal movements remains unknown. We express fluorescently tagged CAs in guard cells of ca1ca4 double-mutantmore » plants and show that the specific locations of βCA4 at the plasma membrane and βCA1 in native guard cell chloroplasts each can mediate rapid CO 2 control of stomatal movements. Localization and complementation analyses using a mammalian αCAII-yellow fluorescent protein in guard cells further show that cytoplasmic localization is also sufficient to restore CO 2 regulation of stomatal conductance. Mathematical modeling of cellular CO 2 catalysis suggests that the dynamics of the intracellular HCO 3 - concentration change in guard cells can be driven by plasma membrane and cytoplasmic localizations of CAs but not as clearly by chloroplast targeting. Therefore, modeling supports the notion that the intracellular HCO 3 - concentration dynamics in guard cells are a key mechanism in mediating CO 2 -regulated stomatal movements but that an additional chloroplast role of CAs exists that has yet to be identified.« less

Roles of microRNA on cancer cell metabolism

PubMed Central

2012-01-01

Advanced studies of microRNAs (miRNAs) have revealed their manifold biological functions, including control of cell proliferation, cell cycle and cell death. However, it seems that their roles as key regulators of metabolism have drawn more and more attention in the recent years. Cancer cells display increased metabolic autonomy in comparison to non-transformed cells, taking up nutrients and metabolizing them in pathways that support growth and proliferation. MiRNAs regulate cell metabolic processes through complicated mechanisms, including directly targeting key enzymes or transporters of metabolic processes and regulating transcription factors, oncogenes / tumor suppressors as well as multiple oncogenic signaling pathways. MiRNAs like miR-375, miR-143, miR-14 and miR-29b participate in controlling cancer cell metabolism by regulating the expression of genes whose protein products either directly regulate metabolic machinery or indirectly modulate the expression of metabolic enzymes, serving as master regulators, which will hopefully lead to a new therapeutic strategy for malignant cancer. This review focuses on miRNA regulations of cancer cell metabolism,including glucose uptake, glycolysis, tricarboxylic acid cycle and insulin production, lipid metabolism and amino acid biogenesis, as well as several oncogenic signaling pathways. Furthermore, the challenges of miRNA-based strategies for cancer diagnosis, prognosis and therapeutics have been discussed. PMID:23164426

Homophilic and heterophilic polycystin 1 interactions regulate E-cadherin recruitment and junction assembly in MDCK cells

PubMed Central

Streets, Andrew J.; Wagner, Bart E.; Harris, Peter C.; Ward, Christopher J.; Ong, Albert C. M.

2009-01-01

Summary Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited human renal disease and is caused by mutations in two genes, PKD1 (85%) and PKD2 (15%). Cyst epithelial cells are characterised by a complex cellular phenotype including changes in proliferation, apoptosis, basement membrane composition and apicobasal polarity. Since polycystin 1 (PC1), the PKD1 protein, has been located in the basolateral membrane of kidney epithelial cells, we hypothesised that it might have a key role in mediating or stabilising cell-cell interactions. In non-ciliated L929 cells, stable or transient surface expression of the PC1 extracellular domain was sufficient to confer an adhesive phenotype and stimulate junction formation. In MDCK cells, we found that PC1 was recruited to the lateral membranes coincident with E-cadherin within 30 minutes after a `calcium switch'. Recruitment of both proteins was significantly delayed when cells were treated with a PC1 blocking antibody raised to the PKD domains. Finally, PC1 and E-cadherin could be coimmunoprecipitated together from MDCK cells. We conclude that PC1 has a key role in initiating junction formation via initial homophilic interactions and facilitates junction assembly and the establishment of apicobasal polarity by E-cadherin recruitment. PMID:19351715

STATs: An Old Story, Yet Mesmerizing.

PubMed

Abroun, Saeid; Saki, Najmaldin; Ahmadvand, Mohammad; Asghari, Farahnaz; Salari, Fatemeh; Rahim, Fakher

2015-01-01

Signal transducers and activators of transcription (STATs) are cytoplasmic transcription factors that have a key role in cell fate. STATs, a protein family comprised of seven members, are proteins which are latent cytoplasmic transcription factors that convey signals from the cell surface to the nucleus through activation by cytokines and growth factors. The signaling pathways have diverse biological functions that include roles in cell differentiation, proliferation, development, apoptosis, and inflammation which place them at the center of a very active area of research. In this review we explain Janus kinase (JAK)/STAT signaling and focus on STAT3, which is transient from cytoplasm to nucleus after phosphorylation. This procedure controls fundamental biological processes by regulating nuclear genes controlling cell proliferation, survival, and development. In some hematopoietic disorders and cancers, overexpression and activation of STAT3 result in high proliferation, suppression of cell differentiation and inhibition of cell maturation. This article focuses on STAT3 and its role in malignancy, in addition to the role of microRNAs (miRNAs) on STAT3 activation in certain cancers.

Mitochondria, calcium, and tumor suppressor Fus1: At the crossroad of cancer, inflammation, and autoimmunity

PubMed Central

Uzhachenko, Roman; Shanker, Anil; Yarbrough, Wendell G.; Ivanova, Alla V.

2015-01-01

Mitochondria present a unique set of key intracellular functions such as ATP synthesis, production of reactive oxygen species (ROS) and Ca2+ buffering. Mitochondria both encode and decode Ca2+ signals and these interrelated functions have a direct impact on cell signaling and metabolism. High proliferative potential is a key energy-demanding feature shared by cancer cells and activated T lymphocytes. Switch of a metabolic state mediated by alterations in mitochondrial homeostasis plays a fundamental role in maintenance of the proliferative state. Recent studies show that tumor suppressors have the ability to affect mitochondrial homeostasis controlling both cancer and autoimmunity. Herein, we discuss established and putative mechanisms of calcium–dependent regulation of both T cell and tumor cell activities. We use the mitochondrial protein Fus1 as a case of tumor suppressor that controls immune response and tumor growth via maintenance of mitochondrial homeostasis. We focus on the regulation of mitochondrial Ca2+ handling as a key function of Fus1 and highlight the mechanisms of a crosstalk between Ca2+ accumulation and mitochondrial homeostasis. Given the important role of Ca2+ signaling, mitochondrial Ca2+ transport and ROS production in the activation of NFAT and NF-κB transcription factors, we outline the importance of Fus1 activities in this context. PMID:26246474

Vesicle Docking Is a Key Target of Local PI(4,5)P2 Metabolism in the Secretory Pathway of INS-1 Cells.

PubMed

Ji, Chen; Fan, Fan; Lou, Xuelin

2017-08-08

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P 2 ) signaling is transient and spatially confined in live cells. How this pattern of signaling regulates transmitter release and hormone secretion has not been addressed. We devised an optogenetic approach to control PI(4,5)P 2 levels in time and space in insulin-secreting cells. Combining this approach with total internal reflection fluorescence microscopy, we examined individual vesicle-trafficking steps. Unlike long-term PI(4,5)P 2 perturbations, rapid and cell-wide PI(4,5)P 2 reduction in the plasma membrane (PM) strongly inhibits secretion and intracellular Ca 2+ concentration ([Ca 2+ ] i ) responses, but not sytaxin1a clustering. Interestingly, local PI(4,5)P 2 reduction selectively at vesicle docking sites causes remarkable vesicle undocking from the PM without affecting [Ca 2+ ] i . These results highlight a key role of local PI(4,5)P 2 in vesicle tethering and docking, coordinated with its role in priming and fusion. Thus, different spatiotemporal PI(4,5)P 2 signaling regulates distinct steps of vesicle trafficking, and vesicle docking may be a key target of local PI(4,5)P 2 signaling in vivo. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

IL-23 Blockade for Crohn s disease: next generation of anti-cytokine therapy.

PubMed

Furfaro, Federica; Gilardi, Daniela; Allocca, Mariangela; Cicerone, Clelia; Correale, Carmen; Fiorino, Gionata; Danese, Silvio

2017-05-01

Adaptive immunity in intestinal inflammation may play a key role in the pathogenesis of Crohn's disease. In particular, interleukin (IL)-23 may be a key mediator in chronic intestinal inflammation by inducing the differentiation of naïve CD4 + T cells into Th17, with the production of several pro-inflammatory cytokines. Furthermore, IL-23 induces interferon-γ (IFN- γ) production from activated T cells, a critical cytokine in innate and adaptive immunity against infections. Areas covered: We aim to review the available data from literature regarding the role of IL-23, with a more specific focus on the recent progresses in the therapeutic modulation of this cytokine. Expert commentary: Increased knowledge regarding the role of IL-23 has allowed for the development of effective therapeutic progresses by blocking the IL-23 mediated pathways. Primary or secondary loss of response to anti-TNF therapies in Crohn's disease patients during the first year is widely described in literature: the development of new drugs, with alternative mechanisms of action, is thus a key point to consider for the optimal management of these subjects. Drugs blocking the IL-12/23 pathway showed a good efficacy and safety profile in immune-mediated diseases Further studies are necessary regarding the role of the single blockade of IL-23.

Inhibitors of the proteasome suppress homologous DNA recombination in mammalian cells.

PubMed

Murakawa, Yasuhiro; Sonoda, Eiichiro; Barber, Louise J; Zeng, Weihua; Yokomori, Kyoko; Kimura, Hiroshi; Niimi, Atsuko; Lehmann, Alan; Zhao, Guang Yu; Hochegger, Helfrid; Boulton, Simon J; Takeda, Shunichi

2007-09-15

Proteasome inhibitors are novel antitumor agents against multiple myeloma and other malignancies. Despite the increasing clinical application, the molecular basis of their antitumor effect has been poorly understood due to the involvement of the ubiquitin-proteasome pathway in multiple cellular metabolisms. Here, we show that treatment of cells with proteasome inhibitors has no significant effect on nonhomologous end joining but suppresses homologous recombination (HR), which plays a key role in DNA double-strand break (DSB) repair. In this study, we treat human cells with proteasome inhibitors and show that the inhibition of the proteasome reduces the efficiency of HR-dependent repair of an artificial HR substrate. We further show that inhibition of the proteasome interferes with the activation of Rad51, a key factor for HR, although it does not affect the activation of ATM, gammaH2AX, or Mre11. These data show that the proteasome-mediated destruction is required for the promotion of HR at an early step. We suggest that the defect in HR-mediated DNA repair caused by proteasome inhibitors contributes to antitumor effect, as HR plays an essential role in cellular proliferation. Moreover, because HR plays key roles in the repair of DSBs caused by chemotherapeutic agents such as cisplatin and by radiotherapy, proteasome inhibitors may enhance the efficacy of these treatments through the suppression of HR-mediated DNA repair pathways.

The Roles of p53 in Mitochondrial Dynamics and Cancer Metabolism: The Pendulum between Survival and Death in Breast Cancer?

PubMed

Moulder, David E; Hatoum, Diana; Tay, Enoch; Lin, Yiguang; McGowan, Eileen M

2018-06-08

Cancer research has been heavily geared towards genomic events in the development and progression of cancer. In contrast, metabolic regulation, such as aberrant metabolism in cancer, is poorly understood. Alteration in cellular metabolism was once regarded simply as a consequence of cancer rather than as playing a primary role in cancer promotion and maintenance. Resurgence of cancer metabolism research has identified critical metabolic reprogramming events within biosynthetic and bioenergetic pathways needed to fulfill the requirements of cancer cell growth and maintenance. The tumor suppressor protein p53 is emerging as a key regulator of metabolic processes and metabolic reprogramming in cancer cells—balancing the pendulum between cell death and survival. This review provides an overview of the classical and emerging non-classical tumor suppressor roles of p53 in regulating mitochondrial dynamics: mitochondrial engagement in cell death processes in the prevention of cancer. On the other hand, we discuss p53 as a key metabolic switch in cellular function and survival. The focus is then on the conceivable roles of p53 in breast cancer metabolism. Understanding the metabolic functions of p53 within breast cancer metabolism will, in due course, reveal critical metabolic hotspots that cancers advantageously re-engineer for sustenance. Illustration of these events will pave the way for finding novel therapeutics that target cancer metabolism and serve to overcome the breast cancer burden.

Hepatic stellate cells: fibrogenic, regenerative or both? Heterogeneity and context are key.

PubMed

Bansal, Meena B

2016-11-01

Since their original identification, our understanding of the role of hepatic stellate cells in both health and disease continues to grow. Numerous studies have delineated the role of stellate cell activation in contributing to the pool of myofibroblasts responsible for liver fibrosis, and these have resulted in the development of a number of anti-fibrotic strategies targeting this cell. However, their potential role in liver regeneration, both initiation and termination, is also emerging and needs to be contemplated when considering targeted therapy. Perhaps what is most striking is the increasing recognition that this is not just one cell, but rather, a heterogenous population made up of a number of different subsets of cells, each with differentiated and specific functions. The tools are emerging for this dissection and are greatly needed to truly develop targeted therapies that will inhibit fibrosis while promoting liver regeneration and repair.

Innovative Strategies for Breast Cancer Immunotherapy

DTIC Science & Technology

2014-09-01

donors, percentages of CD4+ and CD8+ T cells as well as T regulatory cells ( Tregs : FOXP3 and CD25 positive) were determined in K-CAR T cells...obtained from BC patients or normal female donors, since Tregs are a component of the immune system that suppresses immune responses of other cells. A...immunosuppressive mechanisms that inhibit T cell activation (33). Suppression of CD8+ effector cells by CD4+CD25+FoxP3+ regulatory T cells ( Tregs ) plays a key role

Stomach development, stem cells and disease.

PubMed

Kim, Tae-Hee; Shivdasani, Ramesh A

2016-02-15

The stomach, an organ derived from foregut endoderm, secretes acid and enzymes and plays a key role in digestion. During development, mesenchymal-epithelial interactions drive stomach specification, patterning, differentiation and growth through selected signaling pathways and transcription factors. After birth, the gastric epithelium is maintained by the activity of stem cells. Developmental signals are aberrantly activated and stem cell functions are disrupted in gastric cancer and other disorders. Therefore, a better understanding of stomach development and stem cells can inform approaches to treating these conditions. This Review highlights the molecular mechanisms of stomach development and discusses recent findings regarding stomach stem cells and organoid cultures, and their roles in investigating disease mechanisms. © 2016. Published by The Company of Biologists Ltd.

Stomach development, stem cells and disease

PubMed Central

Kim, Tae-Hee; Shivdasani, Ramesh A.

2016-01-01

The stomach, an organ derived from foregut endoderm, secretes acid and enzymes and plays a key role in digestion. During development, mesenchymal-epithelial interactions drive stomach specification, patterning, differentiation and growth through selected signaling pathways and transcription factors. After birth, the gastric epithelium is maintained by the activity of stem cells. Developmental signals are aberrantly activated and stem cell functions are disrupted in gastric cancer and other disorders. Therefore, a better understanding of stomach development and stem cells can inform approaches to treating these conditions. This Review highlights the molecular mechanisms of stomach development and discusses recent findings regarding stomach stem cells and organoid cultures, and their roles in investigating disease mechanisms. PMID:26884394

Androgen receptor (AR) pathophysiological roles in androgen-related diseases in skin, bone/muscle, metabolic syndrome and neuron/immune systems: lessons learned from mice lacking AR in specific cells

PubMed Central

Chang, Chawnshang; Yeh, Shuyuan; Lee, Soo Ok; Chang, Ta-min

2013-01-01

The androgen receptor (AR) is expressed ubiquitously and plays a variety of roles in a vast number of physiological and pathophysiological processes. Recent studies of AR knockout (ARKO) mouse models, particularly the cell type- or tissue-specific ARKO models, have uncovered many AR cell type- or tissue-specific pathophysiological roles in mice, which otherwise would not be delineated from conventional castration and androgen insensitivity syndrome studies. Thus, the AR in various specific cell types plays pivotal roles in production and maturation of immune cells, bone mineralization, and muscle growth. In metabolism, the ARs in brain, particularly in the hypothalamus, and the liver appear to participate in regulation of insulin sensitivity and glucose homeostasis. The AR also plays key roles in cutaneous wound healing and cardiovascular diseases, including atherosclerosis and abdominal aortic aneurysm. This article will discuss the results obtained from the total, cell type-, or tissue-specific ARKO models. The understanding of AR cell type- or tissue-specific physiological and pathophysiological roles using these in vivo mouse models will provide useful information in uncovering AR roles in humans and eventually help us to develop better therapies via targeting the AR or its downstream signaling molecules to combat androgen/AR-related diseases. PMID:24653668

Loss of tight junction barrier function and its role in cancer metastasis.

PubMed

Martin, Tracey A; Jiang, Wen G

2009-04-01

As the most apical structure between epithelial and endothelial cells, tight junctions (TJ) are well known as functioning as a control for the paracellular diffusion of ions and certain molecules. It has however, become increasingly apparent that the TJ has a vital role in maintaining cell to cell integrity and that the loss of cohesion of the structure can lead to invasion and thus metastasis of cancer cells. This article will present data showing how modulation of expression of TJ molecules results in key changes in TJ barrier function leading to the successful metastasis of a number of different cancer types.

β-Cell-specific pyruvate dehydrogenase deficiency impairs glucose-stimulated insulin secretion

PubMed Central

Srinivasan, Malathi; Choi, Cheol S.; Ghoshal, Pushpankur; Pliss, Lioudmila; Pandya, Jignesh D.; Hill, David; Cline, Gary

2010-01-01

Glucose-stimulated insulin secretion (GSIS) by β-cells requires the generation of ATP from oxidation of pyruvate as well as generation of coupling factors involving three different pyruvate cycling shuttles. The roles of several key enzymes involved in pyruvate cycling in β-cells have been documented using isolated islets and β-cell clonal lines. To investigate the role of the pyruvate dehydrogenase (PDH) complex (PDC) in GSIS, a murine model of β-cell-specific PDH deficiency (β-PDHKO) was created. Pancreatic insulin content was decreased in 1-day-old β-PDHKO male pups and adult male mice. The plasma insulin levels were decreased and blood glucose levels increased in β-PDHKO male mice from neonatal life onward. GSIS was reduced in isolated islets from β-PDHKO male mice with about 50% reduction in PDC activity. Impairment in a glucose tolerance test and in vivo insulin secretion during hyperglycemic clamp was evident in β-PDHKO adults. No change in the number or size of islets was found in pancreata from 4-wk-old β-PDHKO male mice. However, an increase in the mean size of individual β-cells in islets of these mice was observed. These findings show a key role of PDC in GSIS by pyruvate oxidation. This β-PDHKO mouse model represents the first mouse model in which a mitochondrial oxidative enzyme deletion by gene knockout has been employed to demonstrate an altered GSIS by β-cells. PMID:20841503

New insights into the pathways initiating and driving pancreatitis

PubMed Central

Gukovskaya, Anna S.; Pandol, Stephen J.; Gukovsky, Ilya

2016-01-01

Purpose of review In this article, we discuss recent studies that advance our understanding of molecular and cellular factors initiating and driving pancreatitis, with the emphasis on the role of acinar cell organelle disorders. Recent findings The central physiologic function of the pancreatic acinar cell – to synthesize, store, and secrete digestive enzymes – critically relies on coordinated actions of the endoplasmic reticulum (ER), the endolysosomal system, mitochondria, and autophagy. Recent studies begin to unravel the roles of these organelles’ disordering in the mechanism of pancreatitis. Mice deficient in key autophagy mediators Atg5 or Atg7, or lysosome-associated membrane protein-2, exhibit dysregulation of multiple signaling and metabolic pathways in pancreatic acinar cells and develop spontaneous pancreatitis. Mitochondrial dysfunction caused by sustained opening of the permeability transition pore is shown to mediate pancreatitis in several clinically relevant experimental models, and its inhibition by pharmacologic or genetic means greatly reduces local and systemic pathologic responses. Experimental pancreatitis is also alleviated with inhibitors of ORAI1, a key component of the plasma membrane channel mediating pathologic rise in acinar cell cytosolic Ca2+. Pancreatitis-promoting mutations are increasingly associated with the ER stress. These findings suggest novel pathways and drug targets for pancreatitis treatment. In addition, the recent studies identify new mediators (e.g., neutrophil extracellular traps) of the inflammatory and other responses of pancreatitis. Summary The recent findings illuminate a critical role of organelles regulating the autophagic, endolysosomal, mitochondrial, and ER pathways in maintaining pancreatic acinar cell homeostasis and secretory function; provide compelling evidence that organelle disordering is a key pathogenic mechanism initiating and driving pancreatitis; and identify molecular and cellular factors that could be targeted to restore organellar functions and thus alleviate or treat pancreatitis. PMID:27428704

Novel Therapeutic Approaches Targeting MDSC in Myelodysplastic Syndrome

DTIC Science & Technology

2016-09-01

hematopoiesis and a propensity for progression to acute myeloid leukemia (AML). MDS are senescence-dependent myeloid malignancies with a rising prevalence owing... myeloid -derived suppressor cells (MDSCs), a heterogeneous group of immature myeloid cells, which play a critical role in MDS pathogenesis. A key...cell death of myeloid progenitors. MDSC-mediated suppressive activity is stimulated by the danger-associated molecular pattern (DAMP) heterodimer

GMI-1070, a novel pan-selectin antagonist, reverses acute vascular occlusions in sickle cell mice

PubMed Central

Chang, Jungshan; Patton, John T.; Sarkar, Arun; Ernst, Beat

2010-01-01

Leukocyte adhesion in the microvasculature influences blood rheology and plays a key role in vaso-occlusive manifestations of sickle cell disease. Notably, polymorphonuclear neutrophils (PMNs) can capture circulating sickle red blood cells (sRBCs) in inflamed venules, leading to critical reduction in blood flow and vaso-occlusion. Recent studies have suggested that E-selectin expression by endothelial cells plays a key role by sending activating signals that lead to the activation of Mac-1 at the leading edge of PMNs, thereby allowing RBC capture. Thus, the inhibition of E-selectin may represent a valuable target in this disease. Here, we have tested the biologic properties of a novel synthetic pan-selectin inhibitor, GMI-1070, with in vitro assays and in a humanized model of sickle cell vaso-occlusion analyzed by intravital microscopy. We have found that GMI-1070 predominantly inhibited E-selectin–mediated adhesion and dramatically inhibited sRBC-leukocyte interactions, leading to improved microcirculatory blood flow and improved survival. These results suggest that GMI-1070 may represent a valuable novel therapeutic intervention for acute sickle cell crises that should be further evaluated in a clinical trial. PMID:20508165

Chemokines beyond chemo-attraction: CXCL10 and its significant role in cancer and autoimmunity.

PubMed

Karin, Nathan; Razon, Hila

2018-09-01

Chemokines are mostly known for their chemotactic properties, and less for their ability to direct the biological function of target cells, including T cells. The current review focuses on a key chemokine named CXCL10 and its role in directing the migratory propertied and biological function of CD4+ and CD8+ T cells in the context of cancer and inflammatory autoimmunity. CXCR3 is a chemokine receptor that is abundant on CD4+ T cells, CD8+ T cells and NK cells. It has three known ligands: CXCL9, CXCL10 and CXCL11. Different studies, including those coming form our laboratory, indicated that aside of attracting CD8+ and CD4+ effector T cells to tumor sites and sites of inflammation CXCL10 directs the polarization and potentiates the biological function of these cells. This makes CXCL10 a "key driver chemokine" and a valid target for therapy of autoimmune diseases such as Inflammatory Bowl's Disease, Multiple Sclerosis, Rheumatoid arthritis and others. As for cancer this motivated different groups, including our group to develop CXCL10 based therapies for cancer due to its ability to enhance T-dependent anti cancer immunity. The current review summarizes these findings and their potential translational implication. Copyright © 2018 Elsevier Ltd. All rights reserved.

Glycolipid presentation to natural killer T cells differs in an organ-dependent fashion

NASA Astrophysics Data System (ADS)

Schmieg, John; Yang, Guangli; Franck, Richard W.; van Rooijen, Nico; Tsuji, Moriya

2005-01-01

It has been shown that dendritic cells (DCs) are able to present glycolipids to natural killer (NK) T cells in vivo. However, the essential role of DCs, as well as the role of other cells in glycolipid presentation, is unknown. Here, we show that DCs are the crucial antigen-presenting cells (APCs) for splenic NK T cells, whereas Kupffer cells are the key APCs for hepatic NK T cells. Both cell types stimulate cytokine production by NK T cells within 2 h of glycolipid administration, but only DCs are involved in the systemic, downstream responses to glycolipid administration. More specifically, CD8+ DCs produce IL-12 in response to glycolipid presentation, which stimulates secondary IFN- production by NK cells in different organs. Different APCs participate in glycolipid presentation to NK T cells in vivo but differ in their involvement in the overall glycolipid response. dendritic cell | Kupffer cell

Disruption of the Aspergillus fumigatus ECM33 homologue results in rapid conidial germination, antifungal resistance and hypervirulence.

PubMed

Romano, Jacob; Nimrod, Guy; Ben-Tal, Nir; Shadkchan, Yona; Baruch, Koti; Sharon, Haim; Osherov, Nir

2006-07-01

The ECM33/SPS2 family of glycosylphosphatidylinositol-anchored proteins plays an important role in maintaining fungal cell wall integrity and virulence. However, the precise molecular role of these proteins is unknown. In this work, AfuEcm33, the gene encoding the ECM33 homologue in the important pathogenic fungus Aspergillus fumigatus, has been cloned and its function analysed. It is shown that disruption of AfuEcm33 results in rapid conidial germination, increased cell-cell adhesion, resistance to the antifungal agent caspofungin and increased virulence in an immunocompromised mouse model for disseminated aspergillosis. These results suggest that the protein encoded by AfuEcm33 is involved in key aspects of cell wall morphogenesis and plays an important role in A. fumigatus virulence.

The Biology of TRAIL and the Role of TRAIL-Based Therapeutics in Infectious Diseases

PubMed Central

Shepard, Brett D.; Badley, Andrew D.

2011-01-01

TNF-related apoptosis inducing ligand (TRAIL) is a key mediator of the innate immune response to infection. While TRAIL-mediated apoptosis plays an essential role in the clearance of virus-infected cells, its physiologic role also includes immunosurveilance for cancer cells. Therapeutics that induce TRAIL-mediated apoptosis in cancer cells remain a focus of ongoing investigation in clinical trials, and much has been learned from these studies regarding the efficacy and toxicity of these interventions. These data, combined with data from numerous preclinical studies that detail the important and multifaceted role of TRAIL during infection with human immunodeficiency virus and other viruses, suggest that therapeutic exploitation of TRAIL signaling offers a novel and efficacious strategy for the management of infectious diseases. PMID:21857885

Catalase Has a Key Role in Protecting Cells from the Genotoxic Effects of Monomethylarsonous Acid, a Highly Active Metabolite of Arsenic

EPA Science Inventory

ABSTRACT Although it is widely known that arsenic-contaminated drinking water causes many diseases, arsenic’s exact mode of action (MOA) is not fully understood. Induction of oxidative stress has been proposed as an important key event in the toxic MOA of arsenic. The author's...

VEGF signaling inside vascular endothelial cells and beyond

PubMed Central

Eichmann, Anne; Simons, Michael

2014-01-01

Vascular endothelial growth factor-A (VEGF-A) has long been recognized as the key regulator of vascular development and function in health and disease. VEGF is a secreted polypeptide that binds to transmembrane tyrosine kinase VEGF receptors on the plasma membrane, inducing their dimerization, activation and assembly of a membrane-proximal signaling complex. Recent studies have revealed that many key events of VEGFR signaling occur inside the endothelial cell and are regulated by endosomal receptor trafficking. Plasma membrane VEGFR interacting molecules, including vascular guidance receptors Neuropilins and Ephrins also regulate VEGFR endocytosis and trafficking. VEGF signaling is increasingly recognized for its roles outside of the vascular system, notably during neural development, and blood vessels regulate epithelial branching morphogenesis. We review here recent advances in our understanding of VEGF signaling and its biological roles. PMID:22366328

Innate Lymphoid Cells: A Promising New Regulator in Fibrotic Diseases.

PubMed

Zhang, Yi; Tang, Jun; Tian, Zhiqiang; van Velkinburgh, Jennifer C; Song, Jianxun; Wu, Yuzhang; Ni, Bing

2016-09-02

Fibrosis is a consequence of chronic inflammation and the persistent accumulation of extracellular matrix, for which the cycle of tissue injury and repair becomes a predominant feature. Both the innate and adaptive immune systems play key roles in the progress of fibrosis. The recently identified subsets of innate lymphoid cells (ILCs), which are mainly localize to epithelial surfaces, have been characterized as regulators of chronic inflammation and tissue remodeling, representing a functional bridge between the innate and adaptive immunity. Moreover, recent research has implicated ILCs as potential contributing factors to several kinds of fibrosis diseases, such as hepatic fibrosis and pulmonary fibrosis. Here, we will summarize and discuss the key roles of ILCs and their related factors in fibrotic diseases and their potential for translation to the clinic.

The CCR4-NOT complex mediates deadenylation and degradation of stem cell mRNAs and promotes planarian stem cell differentiation.

PubMed

Solana, Jordi; Gamberi, Chiara; Mihaylova, Yuliana; Grosswendt, Stefanie; Chen, Chen; Lasko, Paul; Rajewsky, Nikolaus; Aboobaker, A Aziz

2013-01-01

Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology.

The CCR4-NOT Complex Mediates Deadenylation and Degradation of Stem Cell mRNAs and Promotes Planarian Stem Cell Differentiation

PubMed Central

Solana, Jordi; Gamberi, Chiara; Mihaylova, Yuliana; Grosswendt, Stefanie; Chen, Chen; Lasko, Paul; Rajewsky, Nikolaus; Aboobaker, A. Aziz

2013-01-01

Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology. PMID:24367277

Mast Cells: Key Contributors to Cardiac Fibrosis

PubMed Central

Widiapradja, Alexander

2018-01-01

Historically, increased numbers of mast cells have been associated with fibrosis in numerous cardiac pathologies, implicating mast cells in the development of cardiac fibrosis. Subsequently, several approaches have been utilised to demonstrate a causal role for mast cells in animal models of cardiac fibrosis including mast cell stabilising compounds, rodents deficient in mast cells, and inhibition of the actions of mast cell-specific proteases such as chymase and tryptase. Whilst most evidence supports a pro-fibrotic role for mast cells, there is evidence that in some settings these cells can oppose fibrosis. A major gap in our current understanding of cardiac mast cell function is identification of the stimuli that activate these cells causing them to promote a pro-fibrotic environment. This review will present the evidence linking mast cells to cardiac fibrosis, as well as discuss the major questions that remain in understanding how mast cells contribute to cardiac fibrosis. PMID:29329223

A novel enteric neuron-glia coculture system reveals the role of glia in neuronal development.

PubMed

Le Berre-Scoul, Catherine; Chevalier, Julien; Oleynikova, Elena; Cossais, François; Talon, Sophie; Neunlist, Michel; Boudin, Hélène

2017-01-15

Unlike astrocytes in the brain, the potential role of enteric glial cells (EGCs) in the formation of the enteric neuronal circuit is currently unknown. To examine the role of EGCs in the formation of the neuronal network, we developed a novel neuron-enriched culture model from embryonic rat intestine grown in indirect coculture with EGCs. We found that EGCs shape axonal complexity and synapse density in enteric neurons, through purinergic- and glial cell line-derived neurotrophic factor-dependent pathways. Using a novel and valuable culture model to study enteric neuron-glia interactions, our study identified EGCs as a key cellular actor regulating neuronal network maturation. In the nervous system, the formation of neuronal circuitry results from a complex and coordinated action of intrinsic and extrinsic factors. In the CNS, extrinsic mediators derived from astrocytes have been shown to play a key role in neuronal maturation, including dendritic shaping, axon guidance and synaptogenesis. In the enteric nervous system (ENS), the potential role of enteric glial cells (EGCs) in the maturation of developing enteric neuronal circuit is currently unknown. A major obstacle in addressing this question is the difficulty in obtaining a valuable experimental model in which enteric neurons could be isolated and maintained without EGCs. We adapted a cell culture method previously developed for CNS neurons to establish a neuron-enriched primary culture from embryonic rat intestine which was cultured in indirect coculture with EGCs. We demonstrated that enteric neurons grown in such conditions showed several structural, phenotypic and functional hallmarks of proper development and maturation. However, when neurons were grown without EGCs, the complexity of the axonal arbour and the density of synapses were markedly reduced, suggesting that glial-derived factors contribute strongly to the formation of the neuronal circuitry. We found that these effects played by EGCs were mediated in part through purinergic P2Y 1 receptor- and glial cell line-derived neurotrophic factor-dependent pathways. Using a novel and valuable culture model to study enteric neuron-glia interactions, our study identified EGCs as a key cellular actor required for neuronal network maturation. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Cellular and Synaptic Properties of Local Inhibitory Circuits.

PubMed

Hull, Court

2017-05-01

Inhibitory interneurons play a key role in sculpting the information processed by neural circuits. Despite the wide range of physiologically and morphologically distinct types of interneurons that have been identified, common principles have emerged that have shed light on how synaptic inhibition operates, both mechanistically and functionally, across cell types and circuits. This introduction summarizes how electrophysiological approaches have been used to illuminate these key principles, including basic interneuron circuit motifs, the functional properties of inhibitory synapses, and the main roles for synaptic inhibition in regulating neural circuit function. It also highlights how some key electrophysiological methods and experiments have advanced our understanding of inhibitory synapse function. © 2017 Cold Spring Harbor Laboratory Press.

Arabinogalactan-proteins and the research challenges for these enigmatic plant cell surface proteoglycans

PubMed Central

Tan, Li; Showalter, Allan M.; Egelund, Jack; Hernandez-Sanchez, Arianna; Doblin, Monika S.; Bacic, Antony

2012-01-01

Arabinogalactan-proteins (AGPs) are complex glycoconjugates that are commonly found at the cell surface and in secretions of plants. Their location and diversity of structures have made them attractive targets as modulators of plant development but definitive proof of their direct role(s) in biological processes remains elusive. Here we overview the current state of knowledge on AGPs, identify key challenges impeding progress in the field and propose approaches using modern bioinformatic, (bio)chemical, cell biological, molecular and genetic techniques that could be applied to redress these gaps in our knowledge. PMID:22754559

Gnostic cells in the 21st century.

PubMed

Quiroga, Rodrigo Quian

2013-01-01

In this short review, I revise the notion of gnostic cells posited by Konorski, together with similar arguments by James, Lettvin and Barlow--namely, the idea of pontifical, grandmother and cardinal cells, respectively. I then discuss whether the characteristics of the recently discovered concept cells, i.e. neurons in the human medial temporal lobe with a very high degree of specificity and invariance, fit the conjecture of gnostic or grandmother cells and then discuss the key role of concept cells in memory formation.

Critical role of mast cells and peroxisome proliferator-activated receptor gamma (PPARγ) in the induction of myeloid-derived suppressor cells by marijuana cannabidiol in vivo

PubMed Central

Hegde, Venkatesh L.; Singh, Udai P.; Nagarkatti, Prakash S.; Nagarkatti, Mitzi

2015-01-01

Cannabidiol (CBD) is a natural non-psychotropic cannabinoid from marijuana (Cannabis sativa) with anti-epileptic and anti-inflammatory properties. Effect of CBD on naïve immune system is not precisely understood. In this study, we observed that administering CBD into naïve mice triggers robust induction of CD11b+Gr-1+ MDSC in the peritoneum, which expressed functional Arg1, and potently suppressed T cell proliferation ex vivo. Further, CBD-MDSC suppressed LPS-induced acute inflammatory response upon adoptive transfer in vivo. CBD-induced suppressor cells were comprised of CD11b+Ly6-G+Ly6-C+ granulocytic and CD11b+Ly6-G−Ly6-C+ monocytic subtypes, with monocytic MDSC exhibiting higher T cell suppressive function. Induction of MDSC by CBD was markedly attenuated in Kit-mutant (KitW/W-v) mast cell-deficient mice. MDSC response was reconstituted upon transfer of WT bone marrow-derived mast cells in KitW/W-v mice suggesting the key role of cKit (CD117) as well as mast cells. Moreover, mast cell activator compound 48/80 induced significant levels of MDSC in vivo. CBD administration in mice induced G-CSF, CXCL1 and M-CSF, but not GM-CSF. G-CSF was found to play a key role in MDSC mobilization inasmuch as neutralizing G-CSF caused a significant decrease in MDSC. Lastly, CBD enhanced the transcriptional activity of PPARγ in luciferase reporter assay, and PPARγ selective antagonist completely inhibited MDSC induction in vivo suggesting its critical role. Together, the results suggest that CBD may induce activation of PPARγ in mast cells leading to secretion of G-CSF and consequent MDSC mobilization. CBD being a major component of Cannabis, our study indicates that marijuana may modulate or dysregulate the immune system by mobilizing MDSC. PMID:25917103

The Renin-Angiotensin-Aldosterone System in Vascular Inflammation and Remodeling

PubMed Central

Pacurari, Maricica; Kafoury, Ramzi; Tchounwou, Paul B.; Ndebele, Kenneth

2014-01-01

The RAAS through its physiological effectors plays a key role in promoting and maintaining inflammation. Inflammation is an important mechanism in the development and progression of CVD such as hypertension and atherosclerosis. In addition to its main role in regulating blood pressure and its role in hypertension, RAAS has proinflammatory and profibrotic effects at cellular and molecular levels. Blocking RAAS provides beneficial effects for the treatment of cardiovascular and renal diseases. Evidence shows that inhibition of RAAS positively influences vascular remodeling thus improving CVD outcomes. The beneficial vascular effects of RAAS inhibition are likely due to decreasing vascular inflammation, oxidative stress, endothelial dysfunction, and positive effects on regeneration of endothelial progenitor cells. Inflammatory factors such as ICAM-1, VCAM-1, TNFα, IL-6, and CRP have key roles in mediating vascular inflammation and blocking RAAS negatively modulates the levels of these inflammatory molecules. Some of these inflammatory markers are clinically associated with CVD events. More studies are required to establish long-term effects of RAAS inhibition on vascular inflammation, vascular cells regeneration, and CVD clinical outcomes. This review presents important information on RAAS's role on vascular inflammation, vascular cells responses to RAAS, and inhibition of RAAS signaling in the context of vascular inflammation, vascular remodeling, and vascular inflammation-associated CVD. Nevertheless, the review also equates the need to rethink and rediscover new RAAS inhibitors. PMID:24804145

P-glycoprotein binds to ezrin at amino acid residues 149-242 in the FERM domain and plays a key role in the multidrug resistance of human osteosarcoma.

PubMed

Brambilla, Daria; Zamboni, Silvia; Federici, Cristina; Lugini, Luana; Lozupone, Francesco; De Milito, Angelo; Cecchetti, Serena; Cianfriglia, Maurizio; Fais, Stefano

2012-06-15

Overexpression of the mdr1 gene encoding P-glycoprotein (Pgp) exerts a major role in reducing the effectiveness of cytotoxic therapy in osteosarcoma. The interaction between actin and Pgp has been shown to be instrumental in the establishment of multidrug resistance (MDR) in human tumor cells. The cytoskeleton linker ezrin exerts a pivotal role in maintaining the functional connection between actin and Pgp. We investigated the role of ezrin in a human multidrug-resistant osteosarcoma cell line overexpressing Pgp and compared it to its counterpart that overexpresses an ezrin deletion mutant. The results showed that Pgp binds at amino acid residues 149-242 of the N-terminal domain of ezrin. The interaction between ezrin and Pgp occurs in the plasma membrane of MDR cells, where they also co-localize with the ganglioside G(M1) located in lipid rafts. The overexpression of the ezrin deletion mutant entirely restored drug susceptibility of osteosarcoma cells, consistent with Pgp dislocation to cytoplasmic compartments and abrogation of G(M1) /Pgp co-localization at the plasma membrane. Our study provides evidence that ezrin exerts a key role in MDR of human osteosarcoma cells through a Pgp-ezrin-actin connection that is instrumental for the permanence of Pgp into plasma membrane lipid rafts. We also show for the first time that Pgp-binding site is localized to amino acid residues 149-242 of the ezrin Band 4.1, Ezrin/Radixin/Moesin (FERM) domain, thus proposing a specific target for future molecular therapy aimed at counteracting MDR in osteosarcoma patients. Copyright © 2011 UICC.

The Role of PGC-1α in Vascular Regulation: Implications for Atherosclerosis

PubMed Central

Kadlec, Andrew O.; Chabowski, Dawid S.; Ait-Aissa, Karima; Gutterman, David D.

2016-01-01

Mitochondrial dysfunction results in high levels of oxidative stress and mitochondrial damage, leading to disruption of endothelial homeostasis. Recent discoveries have clarified several pathways whereby mitochondrial dysregulation contributes to endothelial dysfunction and vascular disease burden. One such pathway centers around PGC-1α, a transcriptional coactivator linked to mitochondrial biogenesis and antioxidant defense, among other functions. Although primarily investigated for its therapeutic potential in obesity and skeletal muscle differentiation, the ability of PGC-1α to alter a multitude of cellular functions has sparked interest in its role in the vasculature. Within this context, recent studies demonstrate that PGC-1α plays a key role in endothelial cell and smooth muscle cell regulation through effects on oxidative stress, apoptosis, inflammation, and cell proliferation. The ability of PGC-1α to impact these parameters is relevant to vascular disease progression, particularly in relation to atherosclerosis. Upregulation of PGC-1α can prevent the development of, and even encourage regression of, atherosclerotic lesions. Therefore, PGC-1α is poised to serve as a promising target in vascular disease. This review details recent findings related to PGC-1α in vascular regulation, regulation of PGC-1α itself, the role of PGC-1α in atherosclerosis, and therapies that target this key protein. PMID:27312223

Insights into the key roles of epigenetics in matrix macromolecules-associated wound healing.

PubMed

Piperigkou, Zoi; Götte, Martin; Theocharis, Achilleas D; Karamanos, Nikos K

2017-10-24

Extracellular matrix (ECM) is a dynamic network of macromolecules, playing a regulatory role in cell functions, tissue regeneration and remodeling. Wound healing is a tissue repair process necessary for the maintenance of the functionality of tissues and organs. This highly orchestrated process is divided into four temporally overlapping phases, including hemostasis, inflammation, proliferation and tissue remodeling. The dynamic interplay between ECM and resident cells exerts its critical role in many aspects of wound healing, including cell proliferation, migration, differentiation, survival, matrix degradation and biosynthesis. Several epigenetic regulatory factors, such as the endogenous non-coding microRNAs (miRNAs), are the drivers of the wound healing response. microRNAs have pivotal roles in regulating ECM composition during wound healing and dermal regeneration. Their expression is associated with the distinct phases of wound healing and they serve as target biomarkers and targets for systematic regulation of wound repair. In this article we critically present the importance of epigenetics with particular emphasis on miRNAs regulating ECM components (i.e. glycoproteins, proteoglycans and matrix proteases) that are key players in wound healing. The clinical relevance of miRNA targeting as well as the delivery strategies designed for clinical applications are also presented and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Nitric Oxide Plays a Key Role in Ovariectomy-Induced Apoptosis in Anterior Pituitary: Interplay between Nitric Oxide Pathway and Estrogen.

PubMed

Ronchetti, Sonia A; Machiavelli, Leticia I; Quinteros, Fernanda A; Duvilanski, Beatriz H; Cabilla, Jimena P

2016-01-01

Changes in the estrogenic status produce deep changes in pituitary physiology, mainly because estrogens (E2) are one of the main regulators of pituitary cell population. Also, E2 negatively regulate pituitary neuronal nitric oxide synthase (nNOS) activity and expression and may thereby modulate the production of nitric oxide (NO), an important regulator of cell death and survival. Little is known about how ovary ablation affects anterior pituitary cell remodelling and molecular mechanisms that regulate this process have not yet been elucidated. In this work we used freshly dispersed anterior pituitaries as well as cell cultures from ovariectomized female rats in order to study whether E2 deficiency induces apoptosis in the anterior pituitary cells, the role of NO in this process and effects of E2 on the NO pathway. Our results showed that cell activity gradually decreases after ovariectomy (OVX) as a consequence of cell death, which is completely prevented by a pan-caspase inhibitor. Furthermore, there is an increase of fragmented nuclei and DNA cleavage thereby presenting the first direct evidence of the existence of apoptosis in the anterior pituitary gland after OVX. NO production and soluble guanylyl cyclase (sGC) expression in anterior pituitary cells increased concomitantly to the apoptosis. Inhibition of both, NO synthase (NOS) and sGC activities prevented the drop of cell viability after OVX, showing for the first time that increased NO levels and sGC activity observed post-OVX play a key role in the induction of apoptosis. Conversely, E2 and prolactin treatments decreased nNOS expression and activity in pituitary cells from OVX rats in a time- and E2 receptor-dependent manner, thus suggesting interplay between NO and E2 pathways in anterior pituitary.

Nitric Oxide Plays a Key Role in Ovariectomy-Induced Apoptosis in Anterior Pituitary: Interplay between Nitric Oxide Pathway and Estrogen

PubMed Central

Quinteros, Fernanda A.; Duvilanski, Beatriz H.; Cabilla, Jimena P.

2016-01-01

Changes in the estrogenic status produce deep changes in pituitary physiology, mainly because estrogens (E2) are one of the main regulators of pituitary cell population. Also, E2 negatively regulate pituitary neuronal nitric oxide synthase (nNOS) activity and expression and may thereby modulate the production of nitric oxide (NO), an important regulator of cell death and survival. Little is known about how ovary ablation affects anterior pituitary cell remodelling and molecular mechanisms that regulate this process have not yet been elucidated. In this work we used freshly dispersed anterior pituitaries as well as cell cultures from ovariectomized female rats in order to study whether E2 deficiency induces apoptosis in the anterior pituitary cells, the role of NO in this process and effects of E2 on the NO pathway. Our results showed that cell activity gradually decreases after ovariectomy (OVX) as a consequence of cell death, which is completely prevented by a pan-caspase inhibitor. Furthermore, there is an increase of fragmented nuclei and DNA cleavage thereby presenting the first direct evidence of the existence of apoptosis in the anterior pituitary gland after OVX. NO production and soluble guanylyl cyclase (sGC) expression in anterior pituitary cells increased concomitantly to the apoptosis. Inhibition of both, NO synthase (NOS) and sGC activities prevented the drop of cell viability after OVX, showing for the first time that increased NO levels and sGC activity observed post-OVX play a key role in the induction of apoptosis. Conversely, E2 and prolactin treatments decreased nNOS expression and activity in pituitary cells from OVX rats in a time- and E2 receptor-dependent manner, thus suggesting interplay between NO and E2 pathways in anterior pituitary. PMID:27611913

Signed weighted gene co-expression network analysis of transcriptional regulation in murine embryonic stem cells

PubMed Central

Mason, Mike J; Fan, Guoping; Plath, Kathrin; Zhou, Qing; Horvath, Steve

2009-01-01

Background Recent work has revealed that a core group of transcription factors (TFs) regulates the key characteristics of embryonic stem (ES) cells: pluripotency and self-renewal. Current efforts focus on identifying genes that play important roles in maintaining pluripotency and self-renewal in ES cells and aim to understand the interactions among these genes. To that end, we investigated the use of unsigned and signed network analysis to identify pluripotency and differentiation related genes. Results We show that signed networks provide a better systems level understanding of the regulatory mechanisms of ES cells than unsigned networks, using two independent murine ES cell expression data sets. Specifically, using signed weighted gene co-expression network analysis (WGCNA), we found a pluripotency module and a differentiation module, which are not identified in unsigned networks. We confirmed the importance of these modules by incorporating genome-wide TF binding data for key ES cell regulators. Interestingly, we find that the pluripotency module is enriched with genes related to DNA damage repair and mitochondrial function in addition to transcriptional regulation. Using a connectivity measure of module membership, we not only identify known regulators of ES cells but also show that Mrpl15, Msh6, Nrf1, Nup133, Ppif, Rbpj, Sh3gl2, and Zfp39, among other genes, have important roles in maintaining ES cell pluripotency and self-renewal. We also report highly significant relationships between module membership and epigenetic modifications (histone modifications and promoter CpG methylation status), which are known to play a role in controlling gene expression during ES cell self-renewal and differentiation. Conclusion Our systems biologic re-analysis of gene expression, transcription factor binding, epigenetic and gene ontology data provides a novel integrative view of ES cell biology. PMID:19619308

Regulation of Eosinophil Recruitment and Activation by Galectins in Allergic Asthma.

PubMed

Rao, Savita P; Ge, Xiao Na; Sriramarao, P

2017-01-01

Eosinophils are differentiated granulocytes that are recruited from the bone marrow to sites of inflammation via the vascular system. Allergic asthma is characterized by the presence of large numbers of eosinophils in the lungs and airways. Due to their capacity to rapidly release inflammatory mediators such as cytokines, chemokines, growth factors, and cytotoxic granule proteins upon stimulation, eosinophils play a critical role in pro-inflammatory processes in allergen-exposed lungs. Identifying key players and understanding the molecular mechanisms directing eosinophil trafficking and recruitment to inflamed airways is a key to developing therapeutic strategies to limit their influx. Recent studies have brought to light the important role of glycans and glycan binding proteins in regulating recruitment of eosinophils. In addition to the role of previously identified eosinophil- and endothelial-expressed adhesion molecules in mediating eosinophil trafficking and recruitment to the inflamed airways, studies have also indicated a role for galectins (galectin-3) in this process. Galectins are mammalian lectins expressed by various cell types including eosinophils. Intracellularly, they can regulate biological processes such as cell motility. Extracellularly, galectins interact with β-galactosides in cell surface-expressed glycans to regulate cellular responses like production of inflammatory mediators, cell adhesion, migration, and apoptosis. Eosinophils express galectins intracellularly or on the cell surface where they interact with cell surface glycoconjugate receptors. Depending on the type (galectin-1, -3, etc.) and location (extracellular or intracellular, endogenous or exogenously delivered), galectins differentially regulate eosinophil recruitment, activation, and apoptosis and thus exert a pro- or anti-inflammatory outcome. Here, we have reviewed information pertaining to galectins (galectin-1, -3 -9, and -10) that are expressed by eosinophils themselves and/or other cells that play a role in eosinophil recruitment and function in the context of allergic asthma and their potential use as disease biomarkers or therapeutic targets for immunomodulation.

Regulatory mechanism of protein metabolic pathway during the differentiation process of chicken male germ cell.

PubMed

Li, Dong; Zuo, Qisheng; Lian, Chao; Zhang, Lei; Shi, Qingqing; Zhang, Zhentao; Wang, Yingjie; Ahmed, Mahmoud F; Tang, Beibei; Xiao, Tianrong; Zhang, Yani; Li, Bichun

2015-08-01

We explored the regulatory mechanism of protein metabolism during the differentiation process of chicken male germ cells and provide a basis for improving the induction system of embryonic stem cell differentiation to male germ cells in vitro. We sequenced the transcriptome of embryonic stem cells, primordial germ cells, and spermatogonial stem cells with RNA sequencing (RNA-Seq), bioinformatics analysis methods, and detection of the key genes by quantitative reverse transcription PCR (qRT-PCR). Finally, we found 16 amino acid metabolic pathways enriched in the biological metabolism during the differentiation process of embryonic stem cells to primordial germ cells and 15 amino acid metabolic pathways enriched in the differentiation stage of primordial germ cells to spermatogonial stem cells. We found three pathways, arginine-proline metabolic pathway, tyrosine metabolic pathway, and tryptophan metabolic pathway, significantly enriched in the whole differentiation process of embryonic stem cells to spermatogonial stem cells. Moreover, for these three pathways, we screened key genes such as NOS2, ADC, FAH, and IDO. qRT-PCR results showed that the expression trend of these genes were the same to RNA-Seq. Our findings showed that the three pathways and these key genes play an important role in the differentiation process of embryonic stem cells to male germ cells. These results provide basic information for improving the induction system of embryonic stem cell differentiation to male germ cells in vitro.

Naive CD8 T-Cells Initiate Spontaneous Autoimmunity to a Sequestered Model Antigen of the Central Nervous System

ERIC Educational Resources Information Center

Na, Shin-Young; Cao, Yi; Toben, Catherine; Nitschke, Lars; Stadelmann, Christine; Gold, Ralf; Schimpl, Anneliese; Hunig, Thomas

2008-01-01

In multiple sclerosis, CD8 T-cells are thought play a key pathogenetic role, but mechanistic evidence from rodent models is limited. Here, we have tested the encephalitogenic potential of CD8 T-cells specific for the model antigen ovalbumin (OVA) sequestered in oligodendrocytes as a cytosolic molecule. We show that in these "ODC-OVA" mice, the…

Mesothelioma: Identification of the Key Molecular Events Triggered by BAP1

DTIC Science & Technology

2016-04-01

with 5ml of phosphate-buffered saline. The peritoneal cells obtained were pelleted and supernatant was removed for later cytokine analysis. Cells were...Interestingly, BAP1 has been recently shown to regulate the myeloid stem cell compartment via complex alterations of the transcriptional profile, possibly via...regulation of IL-6 activation by asbestos in lung epithelial cells : role of reactive oxygen species. J Immunol 1997; 159: 3921–3928. 43 Occupational

Integrins in T Cell Physiology

PubMed Central

Alabiso, Oscar; Galetto, Alessandra Silvia; Baldanzi, Gianluca

2018-01-01

From the thymus to the peripheral lymph nodes, integrin-mediated interactions with neighbor cells and the extracellular matrix tune T cell behavior by organizing cytoskeletal remodeling and modulating receptor signaling. LFA-1 (αLβ2 integrin) and VLA-4 (α4β1 integrin) play a key role throughout the T cell lifecycle from thymocyte differentiation to lymphocyte extravasation and finally play a fundamental role in organizing immune synapse, providing an essential costimulatory signal for the T cell receptor. Apart from tuning T cell signaling, integrins also contribute to homing to specific target organs as exemplified by the importance of α4β7 in maintaining the gut immune system. However, apart from those well-characterized examples, the physiological significance of the other integrin dimers expressed by T cells is far less understood. Thus, integrin-mediated cell-to-cell and cell-to-matrix interactions during the T cell lifespan still represent an open field of research. PMID:29415483

Sulforaphane plays common and different roles in tumorigenic and nontumorigenic colon cell growth

USDA-ARS?s Scientific Manuscript database

Sulforaphane (SFN) is a naturally occurring member of the isothiocyanate family of chemopreventive agents and the induction of cell cycle arrest and apoptosis is a key mechanism by which SFN exerts its colon cancer prevention. However, little is known about the differential effects of SFN on colon c...

Arsenic enhances the apoptosis induced by interferon gamma: key role of IRF-1.

PubMed

El Bougrini, J; Pampin, M; Chelbi-Alix, M K

2006-05-15

Interferons (IFNs) and arsenic trioxide (As2O3) are known inhibitors of cell proliferation and have been used in the treatment of certain forms of malignancy. IFNgamma treatment of cells leads to tyrosine phosphorylation of STAT1 followed by dimerization that accumulates in the nucleus. This is followed by DNA binding, activation of target gene transcription, dephosphorylation, and return to the cytoplasm. We have shown earlier that IFNgamma and As2O3 act synergistically in acute promyelocytic leukemia cells to upregulate IRF-1 expression and to induce apoptosis. Here, we show that in the human fibrosarcoma cell line 2fTGH, As2O3 prolongs IFNgamma-induced STAT1 phosphorylation resulting in persistent binding of STAT1 to GAS motif leading to an increase in IRF-1 expression which correlated with both higher anti-proliferative effect and increased apoptosis. These biological responses induced by IFNgamma alone or in combination with As2O3 were abolished when IRF-1 expression was down-regulated by RNA interference, thus demonstrating the key role of IRF-1.

Comparative detection of calcium fluctuations in single female sex cells of tobacco to distinguish calcium signals triggered by in vitro fertilization.

PubMed

Peng, Xiong-Bo; Sun, Meng-Xiang; Yang, Hong-Yuan

2009-08-01

Double fertilization is a key process of sexual reproduction in higher plants. The role of calcium in the activation of female sex cells through fertilization has recently received a great deal of attention. The establishment of a Ca(2+)-imaging technique for living, single, female sex cells is a difficult but necessary prerequisite for evaluating the role of Ca(2+) in the transduction of external stimuli, including the fusion with the sperm cell, to internal cellular processes. The present study describes the use of Fluo-3 for reporting the Ca(2+) signal in isolated, single, female sex cells, egg cells and central cells, of tobacco plants. A suitable loading protocol was optimized by loading the cells at pH 5.6 with 2 microM Fluo-3 for 30 min at 30 degrees C. Under these conditions, several key factors related to in vitro fertilization were also investigated in order to test their possible effects on the [Ca(2+)](cyt) of the female sex cells. The results indicated that the bovine serum albumin-fusion system was superior to the polyethlene glycol-fusion system for detecting calcium fluctuations in female sex cells during fertilization. The central cell was fertilized with the sperm cell in bovine serum albumin; however, no evident calcium dynamic was detected, implying that a transient calcium rise might be a specific signal for egg cell fertilization.

SIRT3 Enhances Glycolysis and Proliferation in SIRT3-Expressing Gastric Cancer Cells

PubMed Central

Cui, Yang; Qin, Lili; Wu, Jing; Qu, Xuan; Hou, Chen; Sun, Wenyan; Li, Shiyong; Vaughan, Andrew T. M.; Li, Jian Jian; Liu, Jiankang

2015-01-01

SIRT3 is a key NAD+-dependent protein deacetylase in the mitochondria of mammalian cells, functioning to prevent cell aging and transformation via regulation of mitochondrial metabolic homeostasis. However, SIRT3 is also found to express in some human tumors; its role in these SIRT3-expressing tumor cells needs to be elucidated. This study demonstrated that the expression of SIRT3 was elevated in a group of gastric cancer cells compared to normal gastric epithelial cells. Although SIRT3 expression levels were increased in the gastric tumor tissues compared to the adjacent non-tumor tissues, SIRT3 positive cancer cells were more frequently detected in the intestinal type gastric cancers than the diffuse type gastric cancers, indicating that SIRT3 is linked with subtypes of gastric cancer. Overexpression of SIRT3 promoted cell proliferation and enhanced ATP generation, glucose uptake, glycogen formation, MnSOD activity and lactate production, which were inhibited by SIRT3 knockdown, indicating that SIRT3 plays a role in reprogramming the bioenergetics in gastric tumor cells. Further analysis revealed that SIRT3 interacted with and deacetylated the lactate dehydrogenase A (LDHA), a key protein in regulating anaerobic glycolysis, enhancing LDHA activity. In consistence, a cluster of glycolysis-associated genes was upregulated in the SIRT3-overexpressing gastric tumor cells. Thus, in addition to the well-documented SIRT3-mediated mitochondrial homeostasis in normal cells, SIRT3 may enhance glycolysis and cell proliferation in SIRT3-expressing cancer cells. PMID:26121691

Cell cycle effects of L-sulforaphane, a major antioxidant from cruciferous vegetables: The role of the anaphase promoting complex.

PubMed

Shelley, Zhaoping; Royce, Simon G; Ververis, Katherine; Karagiannis, Tom C

2014-01-01

L-sulforaphane (LSF) is a natural isothiocyanate found in cruciferous vegetables particularly broccoli. LSF has been identified as a potent antioxidant and anti-cancer agent and is widely known to regulate phase II detoxifying enzymes and induce cell cycle arrest or apoptosis in malignant cells in vitro and in vivo. Previous studies have found significant G2/M cell cycle arrest in response to LSF in various model of cancer and results have mainly been attributed to increased cyclin B1 protein levels and increased p21expression. Using genome-wide mRNA-Seq analysis we provide insights into the molecular mechanisms of action of LSF to identify a key pathway in cell cycle progression - the role of the anaphase promoting complex (APC) pathway. We evaluated gene expression changes in human erythroleukemic K562 cells following treatment with 15 μM LSF for 48h and compared them to immortalized human keratinocytes, human microvascular endothelial cells (HMEC-1) cells and normal human umbilical endothelial cells (HUVEC). We identified disparate gene expression changes in response to LSF between malignant and normal cells and immortalized cell lines. The results highlight significant down-regulation of kinase CDK1 which is suggestive that the existence and activity of APC/CDC20 complex will be inhibited along with its associated down-stream degradation of key cell cycle regulators preventing cell cycle progression from mitotic exit.

Targeted mutation of NGN3 gene disrupts pancreatic endocrine cell development in pigs

USDA-ARS?s Scientific Manuscript database

The domestic pig is an attractive model for biomedical research because of the similarities in anatomy and physiology to humans. However, key gaps remain in our understanding of the role of developmental genes in pig, limiting its full potential. In this publication, the role of Neurogenin 3 (NGN3)...

The Role of Immune Escape and Immune Cell Infiltration in Breast Cancer.

PubMed

Steven, André; Seliger, Barbara

2018-03-01

While detailed analysis of aberrant cancer cell signaling pathways and changes in cancer cell DNA has dominated the field of breast cancer biology for years, there now exists increasing evidence that the tumor microenvironment (TME) including tumor-infiltrating immune cells support the growth and development of breast cancer and further facilitate invasion and metastasis formation as well as sensitivity to drug therapy. Furthermore, breast cancer cells have developed different strategies to escape surveillance from the adaptive and innate immune system. These include loss of expression of immunostimulatory molecules, gain of expression of immunoinhibitory molecules such as PD-L1 and HLA-G, and altered expression of components involved in apoptosis. Furthermore, the composition of the TME plays a key role in breast cancer development and treatment response. In this review we will focus on i) the different immune evasion mechanisms used by breast cancer cells, ii) the role of immune cell infiltration in this disease, and (iii) implication for breast cancer-based immunotherapies.

Stem Cells, Progenitor Cells, and Lineage Decisions in the Ovary

PubMed Central

Hummitzsch, Katja; Anderson, Richard A.; Wilhelm, Dagmar; Wu, Ji; Telfer, Evelyn E.; Russell, Darryl L.; Robertson, Sarah A.

2015-01-01

Exploring stem cells in the mammalian ovary has unleashed a Pandora's box of new insights and questions. Recent evidence supports the existence of stem cells of a number of the different cell types within the ovary. The evidence for a stem cell model producing mural granulosa cells and cumulus cells is strong, despite a limited number of reports. The recent identification of a precursor granulosa cell, the gonadal ridge epithelial-like cell, is exciting and novel. The identification of female germline (oogonial) stem cells is still very new and is currently limited to just a few species. Their origins and physiological roles, if any, are unknown, and their potential to produce oocytes and contribute to follicle formation in vivo lacks robust evidence. The precursor of thecal cells remains elusive, and more compelling data are needed. Similarly, claims of very small embryonic-like cells are also preliminary. Surface epithelial cells originating from gonadal ridge epithelial-like cells and from the mesonephric epithelium at the hilum of the ovary have also been proposed. Another important issue is the role of the stroma in guiding the formation of the ovary, ovigerous cords, follicles, and surface epithelium. Immune cells may also play key roles in developmental patterning, given their critical roles in corpora lutea formation and regression. Thus, while the cellular biology of the ovary is extremely important for its major endocrine and fertility roles, there is much still to be discovered. This review draws together the current evidence and perspectives on this topic. PMID:25541635

The roles of peptide hormones during plant root development.

PubMed

Yamada, Masashi; Sawa, Shinichiro

2013-02-01

Peptide hormones are a key mechanism that plants use for cell-cell interactions; these interactions function to coordinate development, growth, and environmental responses among different cells. Peptide signals are produced by one cell and received by receptors in neighboring cells. It has previously been reported that peptide hormones regulate various aspects of plant development. The mechanism of action of peptides in the shoot is well known. However, the function of peptides in the root has been relatively uncharacterized. Recent studies have discovered important roles for peptide hormones in the development of the root meristem, lateral roots, and nodules. In this review, we focus on current findings regarding the function of peptide hormones in root development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Key Role of MicroRNA in the Regulation of Granulocyte Macrophage Colony-stimulating Factor Expression in Murine Alveolar Epithelial Cells during Oxidative Stress*

PubMed Central

Sturrock, Anne; Mir-Kasimov, Mustafa; Baker, Jessica; Rowley, Jesse; Paine, Robert

2014-01-01

GM-CSF is an endogenous pulmonary cytokine produced by normal alveolar epithelial cells (AEC) that is a key defender of the alveolar space. AEC GM-CSF expression is suppressed by oxidative stress through alternations in mRNA turnover, an effect that is reversed by treatment with recombinant GM-CSF. We hypothesized that specific microRNA (miRNA) would play a key role in AEC GM-CSF regulation. A genome-wide miRNA microarray identified 19 candidate miRNA altered in primary AEC during oxidative stress with reversal by treatment with GM-CSF. Three of these miRNA (miR 133a, miR 133a*, and miR 133b) are also predicted to bind the GM-CSF 3′-untranslated region (UTR). PCR for the mature miRNA confirmed induction during oxidative stress that was reversed by treatment with GM-CSF. Experiments using a GM-CSF 3′-UTR reporter construct demonstrated that miR133a and miR133b effects on GM-CSF expression are through interactions with the GM-CSF 3′-UTR. Using lentiviral transduction of specific mimics and inhibitors in primary murine AEC, we determined that miR133a and miR133b suppress GM-CSF expression and that their inhibition both reverses oxidant-induced suppression of GM-CSF expression and increases basal expression of GM-CSF in cells in normoxia. In contrast, these miRNAs are not active in regulation of GM-CSF expression in murine EL4 T cells. Thus, members of the miR133 family play key roles in regulation of GM-CSF expression through effects on mRNA turnover in AEC during oxidative stress. Increased understanding of GM-CSF gene regulation may provide novel miRNA-based interventions to augment pulmonary innate immune defense in lung injury. PMID:24371146

Oxidation of cholesterol moiety of low density lipoprotein in the presence of human endothelial cells or Cu+2 ions: identification of major products and their effects.

PubMed

Bhadra, S; Arshad, M A; Rymaszewski, Z; Norman, E; Wherley, R; Subbiah, M T

1991-04-15

Oxidation of lipoproteins is believed to play a key role in atherogenesis. In this study, low density lipoproteins (LDL) was subjected to oxidation in the presence of either human umbilical vein endothelial cells or with Cu+2 ions and the major oxides formed were identified. While cholesterol-alpha-epoxide (C-alpha EP) was the major product of cholesterol peroxidation in the presence of endothelial cells, cholest-3,5-dien-7-one (CD) predominated in the presence of Cu+2 ion. Both steroids were identified by gas chromatography/mass spectrometry. HDL cholesterol was resistant to oxidation. When tested on human skin fibroblasts in culture C-alpha EP (10 micrograms/ml) caused marked stimulation of 14C-oleate incorporation into cholesterol esters, while CD stimulated cholesterol esterification only mildly. These studies show that a) C-alpha EP is the major peroxidation product of LDL cholesterol moiety in the presence of endothelial cells and b) it causes marked stimulation of cholesterol esterification in cells. C-alpha EP may play a key role in increasing cholesterol esterification noted in atherogenesis.

Study of AMPK-Regulated Metabolic Fluxes in Neurons Using the Seahorse XFe Analyzer.

PubMed

Marinangeli, Claudia; Kluza, Jérome; Marchetti, Philippe; Buée, Luc; Vingtdeux, Valérie

2018-01-01

AMP-activated protein kinase (AMPK) is the intracellular master energy sensor and metabolic regulator. AMPK is involved in cell energy homeostasis through the regulation of glycolytic flux and mitochondrial biogenesis. Interestingly, metabolic dysfunctions and AMPK deregulations are observed in many neurodegenerative diseases, including Alzheimer's. While these deregulations could play a key role in the development of these diseases, the study of metabolic fluxes has remained quite challenging and time-consuming. In this chapter, we describe the Seahorse XFe respirometry assay as a fundamental experimental tool to investigate the role of AMPK in controlling and modulating cell metabolic fluxes in living and intact differentiated primary neurons. The Seahorse XFe respirometry assay allows the real-time monitoring of glycolytic flux and mitochondrial respiration from different kind of cells, tissues, and isolated mitochondria. Here, we specify a protocol optimized for primary neuronal cells using several energy substrates such as glucose, pyruvate, lactate, glutamine, and ketone bodies. Nevertheless, this protocol can easily be adapted to monitor metabolic fluxes from other types of cells, tissues, or isolated mitochondria by taking into account the notes proposed for each key step of this assay.

Glial cells as key players in schizophrenia pathology: recent insights and concepts of therapy.

PubMed

Bernstein, Hans-Gert; Steiner, Johann; Guest, Paul C; Dobrowolny, Henrik; Bogerts, Bernhard

2015-01-01

The past decade has witnessed an explosion of knowledge on the impact of glia for the neurobiological foundation of schizophrenia. A plethora of studies have shown structural and functional abnormalities in all three types of glial cells. There is convincing evidence of reduced numbers of oligodendrocytes, impaired cell maturation and altered gene expression of myelin/oligodendrocyte-related genes that may in part explain white matter abnormalities and disturbed inter- and intra-hemispheric connectivity, which are characteristic signs of schizophrenia. Earlier reports of astrogliosis could not be confirmed by later studies, although the expression of a variety of astrocyte-related genes is abnormal in psychosis. Since astrocytes play a key role in the synaptic metabolism of glutamate, GABA, monoamines and purines, astrocyte dysfunction may contribute to certain aspects of disturbed neurotransmission in schizophrenia. Finally, increased densities of microglial cells and aberrant expression of microglia-related surface markers in schizophrenia suggest that immunological/inflammatory factors are of considerable relevance for the pathophysiology of psychosis. This review describes current evidence for the multifaceted role of glial cells in schizophrenia and discusses efforts to develop glia-directed therapies for the treatment of the disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Mammalian follicular development and atresia: role of apoptosis.

PubMed

Asselin, E; Xiao, C W; Wang, Y F; Tsang, B K

2000-01-01

The regulation of follicular development and atresia is a complex process and involves interactions between endocrine factors (gonadotropins) and intraovarian regulators (sex steroids, growth factors and cytokines) in the control of follicular cell fate (i.e. proliferation, differentiation and programmed cell death). Granulosa and theca cells are key players in this fascinating process. As atresia is the fate of most follicles, understanding of how these physiological regulators participate in determining the destiny of the follicle (to degenerate or to ovulate) at cellular and subcellular levels is fundamental. This short review summarizes the role of intraovarian modulators of programmed cell death in the induction of atresia during follicular development. Copyright 2000 S. Karger AG, Basel

Generation of SMURF2 knockout human cells using the CRISPR/Cas9 system.

PubMed

Manikoth Ayyathan, Dhanoop; Ilić, Nataša; Gil-Henn, Hava; Blank, Michael

2017-08-15

The HECT domain E3 ubiquitin ligase SMURF2 regulates stability of several key protein targets involved in tumorigenesis, cell proliferation, migration, differentiation, and senescence. While altered levels and aberrant cellular distribution of SMURF2 were reported in different types of cancer, its role in tumorigenesis is far from understood. To elucidate the role of SMURF2 in cancer, appropriate human cancer cell models are needed. Here, we describe approaches that can be used to generate human normal and cancer cell strains knocked-out for SMURF2 using the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene-editing technology. Copyright © 2017 Elsevier Inc. All rights reserved.

Induced pluripotent stem cell-derived myeloid phagocytes: disease modeling and therapeutic applications.

PubMed

Goodridge, Helen S

2014-06-01

Myeloid phagocytes (neutrophils, monocytes, macrophages and dendritic cells) have key roles in immune defense, as well as in tissue repair and remodeling. Defective or dysregulated myeloid phagocyte production or function can cause immune dysfunction, blood cell malignancies and inflammatory diseases. The tumor microenvironment can also condition myeloid phagocytes to promote tumor growth. Studies of their physiological and pathophysiological roles and the mechanisms regulating their production and function are crucial for the identification of novel therapeutic targets. In this review, we examine the use of induced pluripotent stem cells to study myeloid phagocytes in human diseases and develop future therapeutic strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nuclear Mechanics and Stem Cell Differentiation.

PubMed

Mao, Xinjian; Gavara, Nuria; Song, Guanbin

2015-12-01

Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.

CD14 is a key mediator of both lysophosphatidic acid and lipopolysaccharide induction of foam cell formation.

PubMed

An, Dong; Hao, Feng; Zhang, Fuqiang; Kong, Wei; Chun, Jerold; Xu, Xuemin; Cui, Mei-Zhen

2017-09-01

Macrophage uptake of oxidized low-density lipoprotein (oxLDL) plays an important role in foam cell formation and the pathogenesis of atherosclerosis. We report here that lysophosphatidic acid (LPA) enhances lipopolysaccharide (LPS)-induced oxLDL uptake in macrophages. Our data revealed that both LPA and LPS highly induce the CD14 expression at messenger RNA and protein levels in macrophages. The role of CD14, one component of the LPS receptor cluster, in LPA-induced biological functions has been unknown. We took several steps to examine the role of CD14 in LPA signaling pathways. Knockdown of CD14 expression nearly completely blocked LPA/LPS-induced oxLDL uptake in macrophages, demonstrating for the first time that CD14 is a key mediator responsible for both LPA- and LPS-induced oxLDL uptake/foam cell formation. To determine the molecular mechanism mediating CD14 function, we demonstrated that both LPA and LPS significantly induce the expression of scavenger receptor class A type I (SR-AI), which has been implicated in lipid uptake process, and depletion of CD14 levels blocked LPA/LPS-induced SR-AI expression. We further showed that the SR-AI-specific antibody, which quenches SR-AI function, blocked LPA- and LPS-induced foam cell formation. Thus, SR-AI is the downstream mediator of CD14 in regulating LPA-, LPS-, and LPA/LPS-induced foam cell formation. Taken together, our results provide the first experimental evidence that CD14 is a novel connecting molecule linking both LPA and LPS pathways and is a key mediator responsible for LPA/LPS-induced foam cell formation. The LPA/LPS-CD14-SR-AI nexus might be the new convergent pathway, contributing to the worsening of atherosclerosis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

The Role of Innate and Adaptive Immune Cells in the Immunopathogenesis of Chronic Obstructive Pulmonary Disease.

PubMed

Nurwidya, Fariz; Damayanti, Triya; Yunus, Faisal

2016-01-01

Chronic obstructive pulmonary disease (COPD) is a chronic and progressive inflammatory disease of the airways and lungs that results in limitations of continuous airflow and is caused by exposure to noxious gasses and particles. A major cause of morbidity and mortality in adults, COPD is a complex disease pathologically mediated by many inflammatory pathways. Macrophages, neutrophils, dendritic cells, and CD8+ T-lymphocytes are the key inflammatory cells involved in COPD. Recently, the non-coding small RNA, micro-RNA, have also been intensively investigated and evidence suggest that it plays a role in the pathogenesis of COPD. Here, we discuss the accumulated evidence that has since revealed the role of each inflammatory cell and their involvement in the immunopathogenesis of COPD. Mechanisms of steroid resistance in COPD will also be briefly discussed.

Potential role of macrophages as immunoregulators of pregnancy

PubMed Central

Mor, Gil; Abrahams, Vikki M

2003-01-01

The role of the maternal immune system during pregnancy has focused mainly on the aspect of immune tolerance to the invading trophoblast and, therefore, fetus. While this is a critical aspect of reproductive immunology, it is also important to consider the function of the maternal immune system in the promotion of implantation and maintenance of pregnancy. Apoptosis or cell death is not the final stage in tissue development. The quick and effective removal of apoptotic cells by tissue macrophages represents a vital process preventing "leak" of self-antigens and promoting the production of proliferative/survival factors. One of the key requirements of apoptotic cell clearance is the resolution of inflammatory conditions, which, as in the case of pregnancy, may have lethal consequences. This review will focus on decidual macrophages and their role on apoptosis and cell clearance during pregnancy. PMID:14651752

Innovative Strategies for Breast Cancer Immunotherapy

DTIC Science & Technology

2014-09-01

as well as T regulatory cells ( Tregs : FOXP3 and CD25 positive) were determined in K-CAR T cells obtained from BC patients or normal female donors...since Tregs are a component of the immune system that suppresses immune responses of other cells. A sample from a BC patient (#243, diagnosed with...33). Suppression of CD8+ effector cells by CD4+CD25+FoxP3+ regulatory T cells ( Tregs ) plays a key role in this immunosuppression (34). Our results

NAD and the aging process: Role in life, death and everything in between.

PubMed

Chini, Claudia C S; Tarragó, Mariana G; Chini, Eduardo N

2017-11-05

Life as we know it cannot exist without the nucleotide nicotinamide adenine dinucleotide (NAD). From the simplest organism, such as bacteria, to the most complex multicellular organisms, NAD is a key cellular component. NAD is extremely abundant in most living cells and has traditionally been described to be a cofactor in electron transfer during oxidation-reduction reactions. In addition to participating in these reactions, NAD has also been shown to play a key role in cell signaling, regulating several pathways from intracellular calcium transients to the epigenetic status of chromatin. Thus, NAD is a molecule that provides an important link between signaling and metabolism, and serves as a key molecule in cellular metabolic sensoring pathways. Importantly, it has now been clearly demonstrated that cellular NAD levels decline during chronological aging. This decline appears to play a crucial role in the development of metabolic dysfunction and age-related diseases. In this review we will discuss the molecular mechanisms responsible for the decrease in NAD levels during aging. Since other reviews on this subject have been recently published, we will concentrate on presenting a critical appraisal of the current status of the literature and will highlight some controversial topics in the field. In particular, we will discuss the potential role of the NADase CD38 as a driver of age-related NAD decline. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Lactate dehydrogenase-A is indispensable for vascular smooth muscle cell proliferation and migration.

PubMed

Kim, Ji-Hyun; Bae, Kwi-Hyun; Byun, Jun-Kyu; Lee, Sungwoo; Kim, Jung-Guk; Lee, In Kyu; Jung, Gwon-Soo; Lee, You Mie; Park, Keun-Gyu

2017-10-07

The proliferation and migration of vascular smooth muscle cells (VSMCs) have been implicated in the pathogenesis of atherosclerosis. Increased aerobic glycolysis is a key feature of cellular phenotypes including cancer and immune cells. However, the role of aerobic glycolysis in the atherogenic phenotype of VSMCs remains largely unknown. Here, we investigated the role of lactate dehydrogenase-A (LDHA), which is a key enzyme for glycolysis, in the proliferation and migration of VSMCs. Activation of primary rat VSMCs with fetal bovine serum (FBS) or platelet-derived growth factor (PDGF) increased their proliferation and migration, glycolytic activity, and expression of LDHA. Wound healing and transwell migration assays demonstrated that small interfering RNA-mediated knockdown of LDHA and pharmacological inhibition of LDHA by oxamate both effectively inhibited VSMC proliferation and migration. Inhibition of LDHA activity by oxamate reduced PDGF-stimulated glucose uptake, lactate production, and ATP production. Taken together, this study shows that enhanced glycolysis in PDGF- or FBS-stimulated VSMCs plays an important role in their proliferation and migration and suggests that LDHA is a potential therapeutic target to prevent vessel lumen constriction during the course of atherosclerosis and restenosis. Copyright © 2017 Elsevier Inc. All rights reserved.

STATs: An Old Story, Yet Mesmerizing

PubMed Central

Abroun, Saeid; Saki, Najmaldin; Ahmadvand, Mohammad; Asghari, Farahnaz; Salari, Fatemeh; Rahim, Fakher

2015-01-01

Signal transducers and activators of transcription (STATs) are cytoplasmic transcription factors that have a key role in cell fate. STATs, a protein family comprised of seven members, are proteins which are latent cytoplasmic transcription factors that convey signals from the cell surface to the nucleus through activation by cytokines and growth factors. The signaling pathways have diverse biological functions that include roles in cell differentiation, proliferation, development, apoptosis, and inflammation which place them at the center of a very active area of research. In this review we explain Janus kinase (JAK)/STAT signaling and focus on STAT3, which is transient from cytoplasm to nucleus after phosphorylation. This procedure controls fundamental biological processes by regulating nuclear genes controlling cell proliferation, survival, and development. In some hematopoietic disorders and cancers, overexpression and activation of STAT3 result in high proliferation, suppression of cell differentiation and inhibition of cell maturation. This article focuses on STAT3 and its role in malignancy, in addition to the role of microRNAs (miRNAs) on STAT3 activation in certain cancers. PMID:26464811

A crucial role for the phosphorylation of STRAP at Ser188 by MPK38 in STRAP-dependent cell death through ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways

PubMed Central

Seong, Hyun-A; Manoharan, Ravi; Ha, Hyunjung

2014-01-01

Serine-threonine kinase receptor-associated protein (STRAP) is a TGF-β receptor-interacting protein that participates in the regulation of cell proliferation and cell death in response to various stresses. Here, we demonstrate that STRAP phosphorylation plays an important role in determining the pro- or anti-apoptotic function of STRAP. Murine protein serine/threonine kinase 38 (MPK38) phosphorylates STRAP at Ser188 via direct interaction. Complex formation between STRAP and MPK38 is mediated by Cys152 and Cys270 of STRAP and Cys339 and Cys377 of MPK38, suggesting the redox dependency of this interaction. MPK38-mediated STRAP Ser188 phosphorylation contributes to the pro-apoptotic function of STRAP by modulating key steps in STRAP-dependent ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways. Moreover, knockdown of endogenous MPK38 using an inducible MPK38 shRNA system and in vivo activation of MPK38 by treatment of HEK293 and STRAP-null MEF cells with 1-chloro-2,4-dinitrobenzene (DNCB), a specific inhibitor of Trx reductase, provide evidence that STRAP Ser188 phosphorylation plays a key role in STRAP-dependent cell death. Adenoviral delivery of MPK38 in mice also demonstrates that STRAP Ser188 phosphorylation in the liver is tightly associated with cell death and proliferation through ASK1, TGF-β, p53, and PI3K/PDK1 pathways, resulting in apoptotic cell death. PMID:25485581

A crucial role for the phosphorylation of STRAP at Ser(188) by MPK38 in STRAP-dependent cell death through ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways.

PubMed

Seong, Hyun-A; Manoharan, Ravi; Ha, Hyunjung

2014-01-01

Serine-threonine kinase receptor-associated protein (STRAP) is a TGF-β receptor-interacting protein that participates in the regulation of cell proliferation and cell death in response to various stresses. Here, we demonstrate that STRAP phosphorylation plays an important role in determining the pro- or anti-apoptotic function of STRAP. Murine protein serine/threonine kinase 38 (MPK38) phosphorylates STRAP at Ser(188) via direct interaction. Complex formation between STRAP and MPK38 is mediated by Cys(152) and Cys(270) of STRAP and Cys(339) and Cys(377) of MPK38, suggesting the redox dependency of this interaction. MPK38-mediated STRAP Ser(188) phosphorylation contributes to the pro-apoptotic function of STRAP by modulating key steps in STRAP-dependent ASK1, TGF-β, p53, and PI3K/PDK1 signaling pathways. Moreover, knockdown of endogenous MPK38 using an inducible MPK38 shRNA system and in vivo activation of MPK38 by treatment of HEK293 and STRAP-null MEF cells with 1-chloro-2,4-dinitrobenzene (DNCB), a specific inhibitor of Trx reductase, provide evidence that STRAP Ser(188) phosphorylation plays a key role in STRAP-dependent cell death. Adenoviral delivery of MPK38 in mice also demonstrates that STRAP Ser(188) phosphorylation in the liver is tightly associated with cell death and proliferation through ASK1, TGF-β, p53, and PI3K/PDK1 pathways, resulting in apoptotic cell death.

VEGF signaling inside vascular endothelial cells and beyond.

PubMed

Eichmann, Anne; Simons, Michael

2012-04-01

Vascular endothelial growth factor-A (VEGF-A) has long been recognized as the key regulator of vascular development and function in health and disease. VEGF is a secreted polypeptide that binds to transmembrane tyrosine kinase VEGF receptors on the plasma membrane, inducing their dimerization, activation and assembly of a membrane-proximal signaling complex. Recent studies have revealed that many key events of VEGFR signaling occur inside the endothelial cell and are regulated by endosomal receptor trafficking. Plasma membrane VEGFR interacting molecules, including vascular guidance receptors Neuropilins and Ephrins also regulate VEGFR endocytosis and trafficking. VEGF signaling is increasingly recognized for its roles outside of the vascular system, notably during neural development, and blood vessels regulate epithelial branching morphogenesis. We review here recent advances in our understanding of VEGF signaling and its biological roles. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Functional Impact of the Intestinal Microbiome on Mucosal Immunity and Systemic Autoimmunity

PubMed Central

Longman, Randy S.; Littman, Dan R.

2016-01-01

Purpose of Review This review will highlight recent advances functionally linking the gut microbiome with mucosal and systemic immune cell activation potentially underlying autoimmunity. Recent Findings Dynamic interactions between the gut microbiome and environmental cues (including diet and medicines) shape the effector potential of the microbial organ. Key bacteria and viruses have emerged, that, in defined microenvironments, play a critical role in regulating effector lymphocyte functions. The coordinated interactions between these different microbial kingdoms—including bacteria, helminths, and viruses (termed transkingdom interactions)—play a critical role in shaping immunity. Emerging strategies to identify immunologically-relevant microbes with the potential to regulate immune cell functions both at mucosal sites and systemically will likely define key diagnostic and therapeutic targets. Summary The microbiome constitutes a critical microbial organ with coordinated interactions that shape host immunity. PMID:26002030

Dendritic cells: key to fetal tolerance?

PubMed

Blois, Sandra M; Kammerer, Ulrike; Alba Soto, Catalina; Tometten, Mareike C; Shaikly, Valerie; Barrientos, Gabriela; Jurd, Richard; Rukavina, Daniel; Thomson, Angus W; Klapp, Burghard F; Fernández, Nelson; Arck, Petra C

2007-10-01

Pregnancy is a unique event in which a fetus, despite being genetically and immunologically different from the mother (a hemi-allograft), develops in the uterus. Successful pregnancy implies avoidance of rejection by the maternal immune system. Fetal and maternal immune cells come into direct contact at the decidua, which is a highly specialized mucous membrane that plays a key role in fetal tolerance. Uterine dendritic cells (DC) within the decidua have been implicated in pregnancy maintenance. DC serve as antigen-presenting cells with the unique ability to induce primary immune responses. Just as lymphocytes comprise different subsets, DC subsets have been identified that differentially control lymphocyte function. DC may also act to induce immunologic tolerance and regulation of T cell-mediated immunity. Current understanding of DC immunobiology within the context of mammalian fetal-maternal tolerance is reviewed and discussed herein.

Immune heterogeneity in neuroinflammation: dendritic cells in the brain.

PubMed

Colton, Carol A

2013-03-01

Dendritic cells (DC) are critical to an integrated immune response and serve as the key link between the innate and adaptive arms of the immune system. Under steady state conditions, brain DC's act as sentinels, continually sampling their local environment. They share this function with macrophages derived from the same basic hemopoietic (bone marrow-derived) precursor and with parenchymal microglia that arise from a unique non-hemopoietic origin. While multiple cells may serve as antigen presenting cells (APCs), dendritic cells present both foreign and self-proteins to naïve T cells that, in turn, carry out effector functions that serve to protect or destroy. The resulting activation of the adaptive response is a critical step to resolution of injury or infection and is key to survival. In this review we will explore the critical roles that DCs play in the brain's response to neuroinflammatory disease with emphasis on how the brain's microenvironment impacts these actions.

LSD1 is Required for Hair Cell Regeneration in Zebrafish.

PubMed

He, Yingzi; Tang, Dongmei; Cai, Chengfu; Chai, Renjie; Li, Huawei

2016-05-01

Lysine-specific demethylase 1 (LSD1/KDM1A) plays an important role in complex cellular processes such as differentiation, proliferation, apoptosis, and cell cycle progression. It has recently been demonstrated that during development, downregulation of LSD1 inhibits cell proliferation, modulates the expression of cell cycle regulators, and reduces hair cell formation in the zebrafish lateral line, which suggests that LSD1-mediated epigenetic regulation plays a key role in the development of hair cells. However, the role of LSD1 in hair cell regeneration after hair cell loss remains poorly understood. Here, we demonstrate the effect of LSD1 on hair cell regeneration following neomycin-induced hair cell loss. We show that the LSD1 inhibitor trans-2-phenylcyclopropylamine (2-PCPA) significantly decreases the regeneration of hair cells in zebrafish after neomycin damage. In addition, immunofluorescent staining demonstrates that 2-PCPA administration suppresses supporting cell proliferation and alters cell cycle progression. Finally, in situ hybridization shows that 2-PCPA significantly downregulates the expression of genes related to Wnt/β-catenin and Fgf activation. Altogether, our data suggest that downregulation of LSD1 significantly decreases hair cell regeneration after neomycin-induced hair cell loss through inactivation of the Wnt/β-catenin and Fgf signaling pathways. Thus, LSD1 plays a critical role in hair cell regeneration and might represent a novel biomarker and potential therapeutic approach for the treatment of hearing loss.

The cells of cajal-retzius: still a mystery one century after.

PubMed

Soriano, Eduardo; Del Río, José Antonio

2005-05-05

Cajal-Retzius (CR) cells are an enigmatic class of neurons located at the surface of the cerebral cortex, playing a major role in cortical development. In this review, we discuss several distinct features of these neurons and the mechanisms by which they regulate cortical development. Many CR cells likely have extracortical origin and undergo cell death during development. Recent genetic studies report unique patterns of gene expression in CR cells, which may help to explain the developmental processes in which they participate. Moreover, a number of studies indicate that CR cells, and their secreted gene product, reelin, are involved in neuronal migration by acting on two key partners, migrating neurons and radial glial cells. Emerging data show that these neurons are a critical part of an early and complex network of neural activity in layer I, supporting the notion that CR cells modulate cortical maturation. Given these key and complex developmental properties, it is therefore conceivable for CR cells to be implicated in the pathogenesis of a variety of neurological disorders.

The Interactive Roles of Lipopolysaccharides and dsRNA/Viruses on Respiratory Epithelial Cells and Dendritic Cells in Allergic Respiratory Disorders: The Hygiene Hypothesis.

PubMed

Lin, Tsang-Hsiung; Su, Hsing-Hao; Kang, Hong-Yo; Chang, Tsung-Hsien

2017-10-23

The original hygiene hypothesis declares "more infections in early childhood protect against later atopy". According to the hygiene hypothesis, the increased incidence of allergic disorders in developed countries is explained by the decrease of infections. Epithelial cells and dendritic cells play key roles in bridging the innate and adaptive immune systems. Among the various pattern-recognition receptor systems of epithelial cells and dendritic cells, including toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) and others, TLRs are the key systems of immune response regulation. In humans, TLRs consist of TLR1 to TLR10. They regulate cellular responses through engagement with TLR ligands, e.g., lipopolysaccharides (LPS) acts through TLR4 and dsRNA acts through TLR3, but there are certain common components between these two TLR pathways. dsRNA activates epithelial cells and dendritic cells in different directions, resulting in allergy-related Th2-skewing tendency in epithelial cells, and Th1-skewing tendency in dendritic cells. The Th2-skewing effect by stimulation of dsRNA on epithelial cells could be suppressed by the presence of LPS above some threshold. When LPS level decreases, the Th2-skewing effect increases. It may be via these interrelated networks and related factors that LPS modifies the allergic responses and provides a plausible mechanism of the hygiene hypothesis. Several hygiene hypothesis-related phenomena, seemingly conflicting, are also discussed in this review, along with their proposed mechanisms.

Targeted inactivation of integrin-linked kinase in hair follicle stem cells reveals an important modulatory role in skin repair after injury.

PubMed

Nakrieko, Kerry-Ann; Rudkouskaya, Alena; Irvine, Timothy S; D'Souza, Sudhir J A; Dagnino, Lina

2011-07-15

Integrin-linked kinase (ILK) is key for normal epidermal morphogenesis, but little is known about its role in hair follicle stem cells and epidermal regeneration. Hair follicle stem cells are important contributors to newly formed epidermis following injury. We inactivated the Ilk gene in the keratin 15--expressing stem cell population of the mouse hair follicle bulge. Loss of ILK expression in these cells resulted in impaired cutaneous wound healing, with substantially decreased wound closure rates. ILK-deficient stem cells produced very few descendants that moved toward the epidermal surface and into the advancing epithelium that covers the wound. Furthermore, those few mutant cells that homed in the regenerated epidermis exhibited a reduced residence time. Paradoxically, ILK-deficient bulge stem cells responded to anagen growth signals and contributed to newly regenerated hair follicles during this phase of hair follicle growth. Thus ILK plays an important modulatory role in the normal contribution of hair follicle stem cell progeny to the regenerating epidermis following injury.

Targeted inactivation of integrin-linked kinase in hair follicle stem cells reveals an important modulatory role in skin repair after injury

PubMed Central

Nakrieko, Kerry-Ann; Rudkouskaya, Alena; Irvine, Timothy S.; D'souza, Sudhir J. A.; Dagnino, Lina

2011-01-01

Integrin-linked kinase (ILK) is key for normal epidermal morphogenesis, but little is known about its role in hair follicle stem cells and epidermal regeneration. Hair follicle stem cells are important contributors to newly formed epidermis following injury. We inactivated the Ilk gene in the keratin 15–expressing stem cell population of the mouse hair follicle bulge. Loss of ILK expression in these cells resulted in impaired cutaneous wound healing, with substantially decreased wound closure rates. ILK-deficient stem cells produced very few descendants that moved toward the epidermal surface and into the advancing epithelium that covers the wound. Furthermore, those few mutant cells that homed in the regenerated epidermis exhibited a reduced residence time. Paradoxically, ILK-deficient bulge stem cells responded to anagen growth signals and contributed to newly regenerated hair follicles during this phase of hair follicle growth. Thus ILK plays an important modulatory role in the normal contribution of hair follicle stem cell progeny to the regenerating epidermis following injury. PMID:21593206

Expanding Role of T Cells in Human Autoimmune Diseases of the Central Nervous System

PubMed Central

Pilli, Deepti; Zou, Alicia; Tea, Fiona; Dale, Russell C.; Brilot, Fabienne

2017-01-01

It is being increasingly recognized that a dysregulation of the immune system plays a vital role in neurological disorders and shapes the treatment of the disease. Aberrant T cell responses, in particular, are key in driving autoimmunity and have been traditionally associated with multiple sclerosis. Yet, it is evident that there are other neurological diseases in which autoreactive T cells have an active role in pathogenesis. In this review, we report on the recent progress in profiling and assessing the functionality of autoreactive T cells in central nervous system (CNS) autoimmune disorders that are currently postulated to be primarily T cell driven. We also explore the autoreactive T cell response in a recently emerging group of syndromes characterized by autoantibodies against neuronal cell-surface proteins. Common methodology implemented in T cell biology is further considered as it is an important determinant in their detection and characterization. An improved understanding of the contribution of autoreactive T cells expands our knowledge of the autoimmune response in CNS disorders and can offer novel methods of therapeutic intervention. PMID:28638382

NKT cell subsets as key participants in liver physiology and pathology

PubMed Central

Bandyopadhyay, Keya; Marrero, Idania; Kumar, Vipin

2016-01-01

Natural killer T (NKT) cells are innate-like lymphocytes that generally recognize lipid antigens and are enriched in microvascular compartments of the liver. NKT cells can be activated by self- or microbial-lipid antigens and by signaling through toll-like receptors. Following activation, NKT cells rapidly secrete pro-inflammatory or anti-inflammatory cytokines and chemokines, and thereby determine the milieu for subsequent immunity or tolerance. It is becoming clear that two different subsets of NKT cells—type I and type II—have different modes of antigen recognition and have opposing roles in inflammatory liver diseases. Here we focus mainly on the roles of both NKT cell subsets in the maintenance of immune tolerance and inflammatory diseases in liver. Furthermore, how the differential activation of type I and type II NKT cells influences other innate cells and adaptive immune cells to result in important consequences for tissue integrity is discussed. It is crucial that better reagents, including CD1d tetramers, be used in clinical studies to define the roles of NKT cells in liver diseases in patients. PMID:26972772

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

Salmina, Kristine, E-mail: kristine@biomed.lu.lv; Jankevics, Eriks, E-mail: eriks@biomed.lu.lv; Huna, Anda, E-mail: anima-l@inbox.lv

We have previously documented that transient polyploidy is a potential cell survival strategy underlying the clonogenic re-growth of tumour cells after genotoxic treatment. In an attempt to better define this mechanism, we recently documented the key role of meiotic genes in regulating the DNA repair and return of the endopolyploid tumour cells (ETC) to diploidy through reduction divisions after irradiation. Here, we studied the role of the pluripotency and self-renewal stem cell genes NANOG, OCT4 and SOX2 in this polyploidy-dependent survival mechanism. In irradiation-resistant p53-mutated lymphoma cell-lines (Namalwa and WI-L2-NS) but not sensitive p53 wild-type counterparts (TK6), low background expressionmore » of OCT4 and NANOG was up-regulated by ionising radiation with protein accumulation evident in ETC as detected by OCT4/DNA flow cytometry and immunofluorescence (IF). IF analysis also showed that the ETC generate PML bodies that appear to concentrate OCT4, NANOG and SOX2 proteins, which extend into complex nuclear networks. These polyploid tumour cells resist apoptosis, overcome cellular senescence and undergo bi- and multi-polar divisions transmitting the up-regulated OCT4, NANOG and SOX2 self-renewal cassette to their descendents. Altogether, our observations indicate that irradiation-induced ETC up-regulate key components of germ-line cells, which potentially facilitate survival and propagation of the tumour cell population.« less

Chromatin remodeling regulates catalase expression during cancer cells adaptation to chronic oxidative stress.

PubMed

Glorieux, Christophe; Sandoval, Juan Marcelo; Fattaccioli, Antoine; Dejeans, Nicolas; Garbe, James C; Dieu, Marc; Verrax, Julien; Renard, Patricia; Huang, Peng; Calderon, Pedro Buc

2016-10-01

Regulation of ROS metabolism plays a major role in cellular adaptation to oxidative stress in cancer cells, but the molecular mechanism that regulates catalase, a key antioxidant enzyme responsible for conversion of hydrogen peroxide to water and oxygen, remains to be elucidated. Therefore, we investigated the transcriptional regulatory mechanism controlling catalase expression in three human mammary cell lines: the normal mammary epithelial 250MK primary cells, the breast adenocarcinoma MCF-7 cells and an experimental model of MCF-7 cells resistant against oxidative stress resulting from chronic exposure to H 2 O 2 (Resox), in which catalase was overexpressed. Here we identify a novel promoter region responsible for the regulation of catalase expression at -1518/-1226 locus and the key molecules that interact with this promoter and affect catalase transcription. We show that the AP-1 family member JunB and retinoic acid receptor alpha (RARα) mediate catalase transcriptional activation and repression, respectively, by controlling chromatin remodeling through a histone deacetylases-dependent mechanism. This regulatory mechanism plays an important role in redox adaptation to chronic exposure to H 2 O 2 in breast cancer cells. Our study suggests that cancer adaptation to oxidative stress may be regulated by transcriptional factors through chromatin remodeling, and reveals a potential new mechanism to target cancer cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Cell cycle proteins in brain in mild cognitive impairment: insights into progression to Alzheimer disease.

PubMed

Keeney, Jeriel T R; Swomley, Aaron M; Harris, Jessica L; Fiorini, Ada; Mitov, Mihail I; Perluigi, Marzia; Sultana, Rukhsana; Butterfield, D Allan

2012-10-01

Recent studies have demonstrated the re-emergence of cell cycle proteins in brain as patients progress from the early stages of mild cognitive impairment (MCI) into Alzheimer's disease (AD). Oxidative stress markers present in AD have also been shown to be present in MCI brain suggesting that these events occur in early stages of the disease. The levels of key cell cycle proteins, such as CDK2, CDK5, cyclin G1, and BRAC1 have all been found to be elevated in MCI brain compared to age-matched control. Further, peptidyl prolyl cis-trans isomerase (Pin1), a protein that plays an important role in regulating the activity of key proteins, such as CDK5, GSK3-β, and PP2A that are involved in both the phosphorylation state of Tau and in the cell cycle, has been found to be oxidatively modified and downregulated in both AD and MCI brain. Hyperphosphorylation of Tau then results in synapse loss and the characteristic Tau aggregation as neurofibrillary tangles, an AD hallmark. In this review, we summarized the role of cell cycle dysregulation in the progression of disease from MCI to AD. Based on the current literature, it is tempting to speculate that a combination of oxidative stress and cell cycle dysfunction conceivably leads to neurodegeneration.

Impaired hair follicle morphogenesis and polarized keratinocyte movement upon conditional inactivation of integrin-linked kinase in the epidermis.

PubMed

Nakrieko, Kerry-Ann; Welch, Ian; Dupuis, Holly; Bryce, Dawn; Pajak, Agnieszka; St Arnaud, René; Dedhar, Shoukat; D'Souza, Sudhir J A; Dagnino, Lina

2008-04-01

Integrin-linked kinase (ILK) is key for cell survival, migration, and adhesion, but little is known about its role in epidermal development and homeostasis in vivo. We generated mice with conditional inactivation of the Ilk gene in squamous epithelia. These mice die perinatally and exhibit skin blistering and severe defects in hair follicle morphogenesis, including greatly reduced follicle numbers, failure to progress beyond very early developmental stages, and pronounced defects in follicular keratinocyte proliferation. ILK-deficient epidermis shows abnormalities in adhesion to the basement membrane and in differentiation. ILK-deficient cultured keratinocytes fail to attach and spread efficiently and exhibit multiple abnormalities in actin cytoskeletal organization. Ilk gene inactivation in cultured keratinocytes causes impaired ability to form stable lamellipodia, to directionally migrate, and to polarize. These defects are accompanied by abnormal distribution of active Cdc42 to cell protrusions, as well as reduced activation of Rac1 upon induction of cell migration in scraped keratinocyte monolayers. Significantly, alterations in cell spreading and forward movement in single cells can be rescued by expression of constitutively active Rac1 or RhoG. Our studies underscore a central and distinct role for ILK in hair follicle development and in polarized cell movements, two key aspects of epithelial morphogenesis and function.

Impaired Hair Follicle Morphogenesis and Polarized Keratinocyte Movement upon Conditional Inactivation of Integrin-linked Kinase in the Epidermis

PubMed Central

Nakrieko, Kerry-Ann; Welch, Ian; Dupuis, Holly; Bryce, Dawn; Pajak, Agnieszka; St. Arnaud, René; Dedhar, Shoukat

2008-01-01

Integrin-linked kinase (ILK) is key for cell survival, migration, and adhesion, but little is known about its role in epidermal development and homeostasis in vivo. We generated mice with conditional inactivation of the Ilk gene in squamous epithelia. These mice die perinatally and exhibit skin blistering and severe defects in hair follicle morphogenesis, including greatly reduced follicle numbers, failure to progress beyond very early developmental stages, and pronounced defects in follicular keratinocyte proliferation. ILK-deficient epidermis shows abnormalities in adhesion to the basement membrane and in differentiation. ILK-deficient cultured keratinocytes fail to attach and spread efficiently and exhibit multiple abnormalities in actin cytoskeletal organization. Ilk gene inactivation in cultured keratinocytes causes impaired ability to form stable lamellipodia, to directionally migrate, and to polarize. These defects are accompanied by abnormal distribution of active Cdc42 to cell protrusions, as well as reduced activation of Rac1 upon induction of cell migration in scraped keratinocyte monolayers. Significantly, alterations in cell spreading and forward movement in single cells can be rescued by expression of constitutively active Rac1 or RhoG. Our studies underscore a central and distinct role for ILK in hair follicle development and in polarized cell movements, two key aspects of epithelial morphogenesis and function. PMID:18234842

Copper chaperone Atox1 plays role in breast cancer cell migration.

PubMed

Blockhuys, Stéphanie; Wittung-Stafshede, Pernilla

2017-01-29

Copper (Cu) is an essential transition metal ion required as cofactor in many key enzymes. After cell uptake of Cu, the metal is transported by the cytoplasmic Cu chaperone Atox1 to P 1B -type ATPases in the Golgi network for incorporation into Cu-dependent enzymes in the secretory path. Cu is vital for many steps of cancer progression and Atox1 was recently suggested to have additional functionality as a nuclear transcription factor. We here investigated the expression level, cellular localization and role in cell migration of Atox1 in an aggressive breast cancer cell line upon combining immunostaining, microscopy and a wound healing assay. We made the unexpected discovery that Atox1 accumulates at lamellipodia borders of migrating cancer cells and Atox1 silencing resulted in migration defects as evidenced from reduced wound closure. Therefore, we have discovered an unknown role of the Cu chaperone Atox1 in breast cancer cell migration. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Innate immunity and the regulation and mobilization of keratinocyte stem cells: are the old players playing a new game?

PubMed

Singh, Ashok; Morris, Rebecca J

2012-09-01

The skin provides an anatomical barrier to physical, chemical and biological agents. Hence, it is not surprising that it has well-developed innate immunity. What we find surprising is that the CD49f(+) /CD34(+) hair follicle stem cells should have an enriched expression profile of so many genes involved in innate immunity. Do these stem cells require extra protection from environmental insults? Or, could there be a new role for these genes? To probe these questions, we first summarize the roles of some key players in epidermal innate immunity. We next focus on their expression in CD49f(+) /CD34(+) hair follicle stem cells. Then, we consider recent data suggesting a new role for these 'old players' in the regulation and mobilization of haematopoietic and mesenchymal stem cells. Finally, we hypothesize that the 'old players' in these hair follicle stem cells may be playing a 'new game'. © 2012 John Wiley & Sons A/S.

Plant parasitic nematode effectors target host defense and nuclear functions to establish feeding cells.

PubMed

Quentin, Michaëel; Abad, Pierre; Favery, Bruno

2013-01-01

Plant parasitic nematodes are microscopic worms, the most damaging species of which have adopted a sedentary lifestyle within their hosts. These obligate endoparasites have a biotrophic relationship with plants, in which they induce the differentiation of root cells into hypertrophied, multinucleate feeding cells (FCs). Effectors synthesized in the esophageal glands of the nematode are injected into the plant cells via the syringe-like stylet and play a key role in manipulating the host machinery. The establishment of specialized FCs requires these effectors to modulate many aspects of plant cell morphogenesis and physiology, including defense responses. This cell reprogramming requires changes to host nuclear processes. Some proteins encoded by parasitism genes target host nuclei. Several of these proteins were immunolocalized within FC nuclei or shown to interact with host nuclear proteins. Comparative genomics and functional analyses are gradually revealing the roles of nematode effectors. We describe here these effectors and their hypothesized roles in the unique feeding behavior of these pests.

Transcriptome-derived stromal and immune scores infer clinical outcomes of patients with cancer.

PubMed

Liu, Wei; Ye, Hua; Liu, Ying-Fu; Xu, Chao-Qun; Zhong, Yue-Xian; Tian, Tian; Ma, Shi-Wei; Tao, Huan; Li, Ling; Xue, Li-Chun; He, Hua-Qin

2018-04-01

The stromal and immune cells that form the tumor microenvironment serve a key role in the aggressiveness of tumors. Current tumor-centric interpretations of cancer transcriptome data ignore the roles of stromal and immune cells. The aim of the present study was to investigate the clinical utility of stromal and immune cells in tissue-based transcriptome data. The 'Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data' (ESTIMATE) algorithm was used to probe diverse cancer datasets and the fraction of stromal and immune cells in tumor tissues was scored. The association between the ESTIMATE scores and patient survival data was asessed; it was indicated that the two scores have implications for patient survival, metastasis and recurrence. Analysis of a colorectal cancer progression dataset revealed that decreased levels immune cells could serve an important role in cancer progression. The results of the present study indicated that trasncriptome-derived stromal and immune scores may be a useful indicator of cancer prognosis.

A critical role for beta cell M3 muscarinic acetylcholine receptors in regulating insulin release and blood glucose homeostasis in vivo.

PubMed

Gautam, Dinesh; Han, Sung-Jun; Hamdan, Fadi F; Jeon, Jongrye; Li, Bo; Li, Jian Hua; Cui, Yinghong; Mears, David; Lu, Huiyan; Deng, Chuxia; Heard, Thomas; Wess, Jürgen

2006-06-01

One of the hallmarks of type 2 diabetes is that pancreatic beta cells fail to release sufficient amounts of insulin in the presence of elevated blood glucose levels. Insulin secretion is modulated by many hormones and neurotransmitters including acetylcholine, the major neurotransmitter of the peripheral parasympathetic nervous system. The physiological role of muscarinic acetylcholine receptors expressed by pancreatic beta cells remains unclear at present. Here, we demonstrate that mutant mice selectively lacking the M3 muscarinic acetylcholine receptor subtype in pancreatic beta cells display impaired glucose tolerance and greatly reduced insulin release. In contrast, transgenic mice selectively overexpressing M3 receptors in pancreatic beta cells show a profound increase in glucose tolerance and insulin release. Moreover, these mutant mice are resistant to diet-induced glucose intolerance and hyperglycemia. These findings indicate that beta cell M3 muscarinic receptors play a key role in maintaining proper insulin release and glucose homeostasis.

The role of dendritic cells in cancer.

PubMed

Hansen, Morten; Andersen, Mads Hald

2017-04-01

Though present in low numbers, dendritic cells (DCs) are recognized as major players in the control of cancer by adaptive immunity. The roles of cytotoxic CD8 + T-cells and Th1 helper CD4 + T-cells are well-documented in murine models of cancer and associated with a profound prognostic impact when infiltrating human tumors, but less information is known about how these T-cells gain access to the tumor or how they are primed to become tumor-specific. Here, we highlight recent findings that demonstrate a vital role of CD103 + DCs, which have been shown to be experts in cross-priming and the induction of anti-tumor immunity. We also focus on two different mediators that impair the function of tumor-associated DCs: prostaglandin E 2 and β-catenin. Both of these mediators seem to be important for the exclusion of T-cells in the tumor microenvironment and may represent key pathways to target in optimized treatment regimens against cancer.

Rho-associated kinase (ROCK) function is essential for cell cycle progression, senescence and tumorigenesis.

PubMed

Kümper, Sandra; Mardakheh, Faraz K; McCarthy, Afshan; Yeo, Maggie; Stamp, Gordon W; Paul, Angela; Worboys, Jonathan; Sadok, Amine; Jørgensen, Claus; Guichard, Sabrina; Marshall, Christopher J

2016-01-14

Rho-associated kinases 1 and 2 (ROCK1/2) are Rho-GTPase effectors that control key aspects of the actin cytoskeleton, but their role in proliferation and cancer initiation or progression is not known. Here, we provide evidence that ROCK1 and ROCK2 act redundantly to maintain actomyosin contractility and cell proliferation and that their loss leads to cell-cycle arrest and cellular senescence. This phenotype arises from down-regulation of the essential cell-cycle proteins CyclinA, CKS1 and CDK1. Accordingly, while the loss of either Rock1 or Rock2 had no negative impact on tumorigenesis in mouse models of non-small cell lung cancer and melanoma, loss of both blocked tumor formation, as no tumors arise in which both Rock1 and Rock2 have been genetically deleted. Our results reveal an indispensable role for ROCK, yet redundant role for isoforms 1 and 2, in cell cycle progression and tumorigenesis, possibly through the maintenance of cellular contractility.

CBX3 promotes colon cancer cell proliferation by CDK6 kinase-independent function during cell cycle

PubMed Central

Fan, Yao; Li, Haiping; Liang, Xiaolong; Xiang, Zheng

2017-01-01

Heterochromatin protein 1γ (CBX3) links histone methylation marks to transcriptional silence, DNA repair and RNA splicing, but a role for CBX3 in cancer remains largely unknown. In this study, we show that CBX3 in colon cancer cells promotes the progression of the cell cycle and proliferation in vitro and in vivo. Cell cycle (G1 phase to S phase) related gene CDK6 and p21 were further identified as targets of CBX3. In addition, we found that enhancing CDK6 suppresses cell proliferation by upregulating inhibitor p21 in the absence of CBX3, and this function is independent of the kinase activity of CDK6. Our results demonstrate a key role of CBX3 in colon carcinogenesis via suppressing the expression of CDK6/p21, which may disrupt the role of CDK6 in transcriptionally regulating p21, as part of a negative feedback loop to limit CDK6 excessive activation. PMID:28193906

The Role of Gastrointestinal Hormones in Hepatic Lipid Metabolism

PubMed Central

Mells, Jamie Eugene; Anania, Frank A.

2014-01-01

Hepatocellular accumulation of free fatty acids (FFAs) in the form of triglycerides constitutes the metabolic basis for the development of nonalcoholic fatty liver disease (NAFLD). Recent data demonstrate that excess FFA hepatocyte storage is likely to lead to lipotoxicity and hepatocyte apoptosis. Hence, FFA-mediated hepatocyte injury is a key contributor to the pathogenesis of nonalcoholic steatohepatitis (NASH). Nonalcoholic steatohepatitis, obesity, type 2 diabetes, essential hypertension, and other common medical problems together comprise metabolic syndrome. Evidence suggests that peptide hormones from the L cells of the distal small intestine, which comprise the core of the enteroendocrine system (EES), play two key roles, serving either as incretins, or as mediators of appetite and satiety in the central nervous system. Recent data related to glucagon-like peptide-1 (GLP-1) and other known L-cell hormones have accumulated due to the increasing frequency of bariatric surgery, which increase delivery of bile salts to the hindgut. Bile acids are a key stimulus for the TGR5 receptor of the L cells. Enhanced bile-salt flow and subsequent EES stimulation may be central to elimination of hepatic steatosis following bariatric surgery. Although GLP-1 is a clinically relevant pharmacological analogue that drives pancreatic β-cell insulin output, GLP-1 analogues also have independent benefits via their effects on hepatocellular FFA metabolism. The authors also discuss recent data regarding the role of the major peptides released by the EES, which promote satiety and modulate energy homeostasis and utilization, as well as those that control fat absorption and intestinal permeability. Taken together, elucidating novel functions for EES-related peptides and pharmacologic development of peptide analogues offer potential far-ranging treatment for obesity-related human disease. PMID:24222092

ESCRT proteins

PubMed Central

Tu, Chun; Ahmad, Gulzar; Mohapatra, Bhopal; Bhattacharyya, Sohinee; Ortega-Cava, Cesar F; Chung, Byung Min; Wagner, Kay-Uwe; Raja, Srikumar M; Naramura, Mayumi; Band, Vimla

2011-01-01

ESCRT pathway proteins play a key role in sorting ubiquitinated membrane receptors towards lysosomes providing an important mechanism for attenuating cell surface receptor signaling. However, recent studies point to a positive role of ESCRT proteins in signal transduction in multiple species studied under physiological and pathological conditions. ESCRT components such as Tsg101 and Hrs are overexpressed in human cancers and Tsg101 depletion is detrimental for cell proliferation, survival and transformed phenotype of tumor cells. However, the mechanisms underlying the positive contributions of ESCRT pathway to surface receptor signaling have remained unclear. In a recent study, we showed that Tsg101 and Vps4 are essential for translocation of active Src from endosomes to focal adhesion and invadopodia, thereby revealing a role of ESCRT pathway in promoting Src-mediated migration and invasion. We discuss the implications of these and other recent studies which together suggest a role for the ESCRT pathway in recycling of endocytic cargo proteins, aside from its role in lysosomal targeting, potentially explaining the positive roles of ESCRT proteins in signal transduction. PMID:21866262

The role of natural killer cells in autoimmune blistering diseases.

PubMed

Zakka, L R; Fradkov, E; Keskin, D B; Tabansky, I; Stern, J N H; Ahmed, A R

2012-02-01

The major focus of this paper is to describe and evaluate current information on the role of natural killer cells (NK cells) in the pathogenesis of blistering diseases. Until now, only pemphigus vulgaris (PV) has been studied. One co-culture study demonstrated that CD4+ T cells from the peripheral blood or perilesional skin of patients with active disease proliferate and secrete cytokines in the presence of major histocompatibility class II-expressing NK cells loaded with antigenic desmoglein self-peptides. Another study showed that NK cells can contribute to a T helper type 2-biased immune response through impaired interleukins (IL)-12 signaling and upregulation of IL, IL-10 and IL-5. Although significant data on other blistering diseases are unavailable at present, some studies implicate NK cells in disease progression. For instance, information on the role of NK cells in psoriasis and their production of tumor necrosis factor-α (TNF-α) will be provided since several TNF-α-inhibitors are used in its treatment. Studies on alopecia areata are also included in this paper because NK cells seem to play a key role in its pathogenesis. This review highlights the potential importance of NK cells and NKT cells as members of the large repertoire of cells and soluble mediators that play a critical role in pathogenesis of blistering diseases and other autoimmune diseases involving the skin. Therefore, the authors advocate a greater focus and interest on the study of the interaction of NK cells and the skin.

Thioredoxin: a key regulator of cardiovascular homeostasis.

PubMed

Yamawaki, Hideyuki; Haendeler, Judith; Berk, Bradford C

2003-11-28

The thioredoxin (TRX) system (TRX, TRX reductase, and NADPH) is a ubiquitous thiol oxidoreductase system that regulates cellular reduction/oxidation (redox) status. The oxidation mechanism for disease pathogenesis states that an imbalance in cell redox state alters function of multiple cell pathways. In this study, we review the essential role for TRX to limit oxidative stress directly via antioxidant effects and indirectly by protein-protein interaction with key signaling molecules, such as apoptosis signal-regulating kinase 1. We propose that TRX and its endogenous regulators are important future targets to develop clinical therapies for cardiovascular disorders associated with oxidative stress.

Fuel Cell Technology and Its Importance to Society

ERIC Educational Resources Information Center

Hudak, Glenn A.

2005-01-01

Fuel cells may seem like a science fiction fantasy to many people, since they are an efficient and nonpolluting power source producing little noise and having no moving parts. But this futuristic energy source not only exists, it has played a key role in providing electricity on spacecraft since the 1960s. Currently, technologists are developing…

Cardiac stem cell biology: glimpse of the past, present, and future.

PubMed

Matsa, Elena; Sallam, Karim; Wu, Joseph C

2014-01-03

Cardiac regeneration strategies and de novo generation of cardiomyocytes have long been significant areas of research interest in cardiovascular medicine. In this review, we outline a variety of common cell sources and methods used to regenerate cardiomyocytes and highlight the important role that key Circulation Research articles have played in this flourishing field.

Center for Cancer Research plays key role in first FDA-approved drug for treatment of Merkel cell carcinoma | Center for Cancer Research

Cancer.gov

The Center for Cancer Research’s ability to rapidly deploy integrated basic and clinical research teams at a single site facilitated the rapid FDA approval of the immunotherapy drug avelumab for metastatic Merkel cell carcinoma, a rare, aggressive form of skin cancer. Learn more...  

HOX Genes as Potential Markers of Circulating Tumour Cells.

PubMed

Morgan, R; El-Tanani, M

2016-01-01

Circulating tumour cells (CTCs) have significant diagnostic potential as they can reflect both the presence and recurrence of a wide range of cancers. However, this potential continues to be limited by the lack of robust and accessible isolation technologies. An alternative to isolation might be their direct detection amongst other peripheral blood cells, although this would require markers that allow them to be distinguished from an exceptionally high background signal. This review assesses the potential role of HOX genes, a family of homeodomain containing transcription factors with key roles in both embryonic development and oncogenesis, as unique and possibly disease specific markers of CTCs.

The role of α9β1 integrin and its ligands in the development of autoimmune diseases.

PubMed

Kon, Shigeyuki; Uede, Toshimitsu

2018-03-01

Adhesion of cells to extracellular matrix proteins through integrins expressed on the cell surface is important for cell adhesion/motility, survival, and differentiation. Recently, α9β1 integrin was reported to be important for the development of autoimmune diseases including rheumatoid arthritis, multiple sclerosis, and their murine models. In addition, ligands for α9β1 integrin, such as osteopontin and tenascin-C, are well established as key regulators of autoimmune diseases. Therefore, this review focused on the role of interactions between α9β1 integrin and its ligands in the development of autoimmune diseases.

Genetic analysis of salt tolerance in Arabidopsis: Evidence for the role of Ca(2+)/H(+) transporter CAX1

USDA-ARS?s Scientific Manuscript database

Coordinate regulation of transporters at both the plasma membrane and vacuole contribute to plant cell's ability to adapt to a changing environment and play a key role in the maintenance of the chemiosmotic circuits required for cellular growth. The plasma membrane (PM) Na+/H+ antiporter SOS1 is inv...

MicroRNA expression profiling of Leishmania donovani-infected host cells uncovers the regulatory role of MIR30A-3p in host autophagy.

PubMed

Singh, Alok Kumar; Pandey, Rajeev Kumar; Shaha, Chandrima; Madhubala, Rentala

2016-10-02

Leishmania is an obligate intracellular parasite that replicates inside phagolysosomes or parasitophorous vacuoles (PV) of the monocyte/macrophage lineage. It reprograms macrophages and produces a metabolic state conducive to successful infection and multiplication. MicroRNAs (miRNAs), a class of small 22 to 24 nucleotide noncoding regulatory RNAs alter the gene expression and consequently proteome output by targeting mRNAs, may play a regulatory role in modulating host cell functions. In the present study, we demonstrate the novel regulatory role of host microRNA, MIR30A-3p in modulation of host cell macroautophagy/autophagy after infection with L. donovani. Our in vitro studies showed that MIR30A-3p expression was significantly enhanced after L. donovani infection in a time-dependent manner. Transient transfection with a MIR30A-3p inhibitor followed by L. donovani infection promoted the autophagic response and decreased the intracellular parasite burden in both THP-1 cells and human monocyte-derived macrophages (HsMDM). BECN1/Beclin 1, the mammalian ortholog of yeast Vps30/Atg6, is a key autophagy-promoting protein that plays a key role in the regulation of cell death and survival. We report BECN1-dependent modulation of host cell autophagy in response to L. donovani infection. Pretreatment of L. donovani-infected macrophages with the MIR30A-3p mimic decreased and with antagomir increased the expression of BECN1 protein. We demonstrate that BECN1 is a potential target of MIR30A-3p and this miRNA negatively regulates BECN1 expression. Our present study reveals for the first time a novel role of MIR30A-3p in regulating autophagy-mediated L. donovani elimination by targeting BECN1. The present study has significant impact for the treatment of visceral leishmaniasis.

Drug-tolerant persister cancer cells are vulnerable to GPX4 inhibition* | Office of Cancer Genomics

Cancer.gov

Acquired drug resistance prevents cancer therapies from achieving stable and complete responses. Emerging evidence implicates a key role for non-mutational drug resistance mechanisms underlying the survival of residual cancer 'persister' cells. The persister cell pool constitutes a reservoir from which drug-resistant tumours may emerge. Targeting persister cells therefore presents a therapeutic opportunity to impede tumour relapse. We previously found that cancer cells in a high mesenchymal therapy-resistant cell state are dependent on the lipid hydroperoxidase GPX4 for survival.

Untangling the mechanism of 3-methyladenine (3-MA) in enhancing the specific productivity: Transcriptome analysis of recombinant CHO cells treated with 3-MA.

PubMed

Baek, Eric; Lee, Jae Seong; Lee, Gyun Min

2018-06-25

3-Methyladenine (3-MA) is a chemical additive that enhances the specific productivity (q p ) in recombinant Chinese hamster ovary (rCHO) cell lines. Different from its widely known function of inhibiting autophagy, 3-MA has instead shown to increase autophagic flux in various rCHO cell lines. Thus, the mechanism by which 3-MA enhances the q p requires investigation. To evaluate the effect of 3-MA on transcriptome dynamics in rCHO cells, RNA-seq was performed with Fc-fusion protein-producing rCHO cells treated with 3-MA. By analyzing genes that were differentially expressed following the addition of 3-MA during culture, the role of 3-MA in the biological processes of rCHO cells was identified. One pathway markedly influenced by the addition of 3-MA was the unfolded protein response (UPR). Having a close relationship with autophagy, the UPR reestablishes protein folding homeostasis under endoplasmic reticulum (ER) stress. The addition of 3-MA increased the expression of key regulators of the UPR, such as Atf4, Ddit3, and Creb3l3, further supporting the idea that the enhancement of ER capacity acts as a key in increasing the q p . Consequently, the downstream effectors of UPR, which include autophagy-promoting genes, were upregulated as well. Hence, the role of 3-MA in increasing UPR pathway could have made a salient contribution to the increased autophagic flux in rCHO cells. Taken together, transcriptome analysis improved the understanding of the role of 3-MA in gene expression dynamics in rCHO cells and its mechanism in enhancing the q p . This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Diabetic Ketoacidosis

MedlinePlus

... key role in helping sugar (glucose) — a major source of energy for your muscles and other tissues — enter your ... can be fatal. Causes Sugar is a main source of energy for the cells that make up your muscles ...

MiR-23b controls ALDH1A1 expression in cervical cancer stem cells.

PubMed

Wang, Weiwen; Li, Yang; Liu, Na; Gao, Yu; Li, Long

2017-04-27

Cancer stem cells has been widely investigated due to its essential role in cancer progression and drug resistance. Here, we try to find a new therapeutic target for cervical cancer stem cells. We detected ALDH1A1-associated miRNAs expression in our isolated tumorspheres and their corresponding parental cells. Sphere formation assay was also used to determine stemness after cells were manipulated with miR-23b plasmid or miR-23b inhibitor. We found that miR-23b was under-expressed in cervical cancer stem cells to maintain high levels of ALDH1A1. Introduction of miR-23b into cervical cancer cells could alter stemness and cisplatin sensitivity. miR-23b plays key role in maintaining stemness of cervical cancer stem cells and can be developed as therapeutic target to better fight against cervical cancer.

Evidence that Meningeal Mast Cells Can Worsen Stroke Pathology in Mice

PubMed Central

Arac, Ahmet; Grimbaldeston, Michele A.; Nepomuceno, Andrew R.B.; Olayiwola, Oluwatobi; Pereira, Marta P.; Nishiyama, Yasuhiro; Tsykin, Anna; Goodall, Gregory J.; Schlecht, Ulrich; Vogel, Hannes; Tsai, Mindy; Galli, Stephen J.; Bliss, Tonya M.; Steinberg, Gary K.

2015-01-01

Stroke is the leading cause of adult disability and the fourth most common cause of death in the United States. Inflammation is thought to play an important role in stroke pathology, but the factors that promote inflammation in this setting remain to be fully defined. An understudied but important factor is the role of meningeal-located immune cells in modulating brain pathology. Although different immune cells traffic through meningeal vessels en route to the brain, mature mast cells do not circulate but are resident in the meninges. With the use of genetic and cell transfer approaches in mice, we identified evidence that meningeal mast cells can importantly contribute to the key features of stroke pathology, including infiltration of granulocytes and activated macrophages, brain swelling, and infarct size. We also obtained evidence that two mast cell-derived products, interleukin-6 and, to a lesser extent, chemokine (C-C motif) ligand 7, can contribute to stroke pathology. These findings indicate a novel role for mast cells in the meninges, the membranes that envelop the brain, as potential gatekeepers for modulating brain inflammation and pathology after stroke. PMID:25134760

Bacterial morphogenesis and the enigmatic MreB helix.

PubMed

Errington, Jeff

2015-04-01

Work over the past decade has highlighted the pivotal role of the actin-like MreB family of proteins in the determination and maintenance of rod cell shape in bacteria. Early images of MreB localization revealed long helical filaments, which were suggestive of a direct role in governing cell wall architecture. However, several more recent, higher-resolution studies have questioned the existence or importance of the helical structures. In this Opinion article, I navigate a path through these conflicting reports, revive the helix model and summarize the key questions that remain to be answered.

A new function for the yeast trehalose-6P synthase (Tps1) protein, as key pro-survival factor during growth, chronological ageing, and apoptotic stress.

PubMed

Petitjean, Marjorie; Teste, Marie-Ange; Léger-Silvestre, Isabelle; François, Jean M; Parrou, Jean-Luc

2017-01-01

Looking back to our recent work that challenged the paradigm of trehalose in stress resistance in yeast, our objective was to revisit the role of this disaccharide in chronological life span (CLS), and in the control of apoptosis. Using a catalytically dead variant of the trehalose-6-phosphate synthase (Tps1) protein, (the first enzyme in the trehalose biosynthetic pathway), and by manipulating intracellular trehalose independently of this pathway, we demonstrated that trehalose has no role in CLS or in the inhibition of acetic acid or H 2 0 2 -triggered cell death. We showed instead that, in the absence of any apoptotic stimulus, the Tps1 protein itself was necessary in preventing massive, spontaneous commitment of yeast cells to apoptosis during growth. Without Tps1p, the life span was shortened and cells were sensitized to acetic acid (AA) and H 2 0 2 , whereas the overexpression of the inactive variant of Tps1p almost abolished AA-triggered apoptosis. Genetic interaction analysis of TPS1 and genes such as YCA1, NUC1 and AIF1 indicated that these key executioners of cell death partially relayed tps1Δ-triggered signaling. Our results suggested that the pro-survival role of Tps1p could be connected with its ability to preserve ATP levels in yeast cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

PPAR-γ in innate and adaptive lung immunity.

PubMed

Nobs, Samuel Philip; Kopf, Manfred

2018-05-16

The transcription factor PPAR-γ (peroxisome proliferator-activated receptor-γ) is a key regulator of lung immunity exhibiting multiple cell type specific roles in controlling development and function of the lung immune system. It is strictly required for the generation of alveolar macrophages by controlling differentiation of fetal lung monocyte precursors. Furthermore, it plays an important role in lung allergic inflammation by licensing lung dendritic cell t helper 2 (Th2) priming capacity as well as acting as a master transcription factor for pathogenic Th2 cells. Due to this plethora of functions and its involvement in multiple pulmonary diseases including asthma and pulmonary alveolar proteinosis, understanding the role of PPAR-γ in lung immunity is an important subject of ongoing research. ©2018 Society for Leukocyte Biology.

The variable role of SIRT1 in the maintenance and differentiation of mesenchymal stem cells.

PubMed

Zainabadi, Kayvan

2018-04-01

SIRT1 is an NAD + -dependent deacetylase that acts as a nutrient sensitive regulator of longevity. SIRT1 also acts as a key regulator of mesenchymal stem cells (MSCs), adult stem cells that give rise to tissues such as bone, fat, muscle and cartilage. This review focuses on how SIRT1 regulates the self-renewal, multipotency and differentiation of MSCs. The variable role of SIRT1 in promoting the differentiation of MSCs towards certain lineages, while repressing others, will be examined within the broader context of aging, calorie restriction, and regenerative medicine. Finally, recent animal and human studies will be highlighted which paint an overall salutary role for SIRT1 in protecting MSCs (and resulting tissues) from age-related atrophy and dysfunction.

Role of calcium permeable channels in dendritic cell migration.

PubMed

Sáez, Pablo J; Sáez, Juan C; Lennon-Duménil, Ana-María; Vargas, Pablo

2018-06-01

Calcium ion (Ca 2+ ) is an essential second messenger involved in multiple cellular and subcellular processes. Ca 2+ can be released and sensed globally or locally within cells, providing complex signals of variable amplitudes and time-scales. The key function of Ca 2+ in the regulation of acto-myosin contractility has provided a simple explanation for its role in the regulation of immune cell migration. However, many questions remain, including the identity of the Ca 2+ stores, channels and upstream signals involved in this process. Here, we focus on dendritic cells (DCs), because their immune sentinel function heavily relies on their capacity to migrate within tissues and later on between tissues and lymphoid organs. Deciphering the mechanisms by which cytoplasmic Ca 2+ regulate DC migration should shed light on their role in initiating and tuning immune responses. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Role of Bitter and Sweet Taste Receptors in Upper Airway Immunity

PubMed Central

Workman, Alan D.; Palmer, James N.; Adappa, Nithin D.

2016-01-01

Over the past several years, taste receptors have emerged as key players in the regulation of innate immune defenses in the mammalian respiratory tract. Several cell types in the airway, including ciliated epithelial cells, solitary chemosensory cells, and bronchial smooth muscle cells, all display chemoresponsive properties that utilize taste receptors. A variety of bitter products secreted by microbes are detected with resultant downstream inflammation, increased mucous clearance, antimicrobial peptide secretion, and direct bacterial killing. Genetic variation of bitter taste receptors also appears to play a role in the susceptibility to infection in respiratory disease states, including that of chronic rhinosinusitis. Ongoing taste receptor research may yield new therapeutics that harness innate immune defenses in the respiratory tract and may offer alternatives to antibiotic treatment. The present review discusses taste receptor-protective responses and analyzes the role these receptors play in mediating airway immune function. PMID:26492878

Microglia and Beyond: Innate Immune Cells As Regulators of Brain Development and Behavioral Function.

PubMed

Lenz, Kathryn M; Nelson, Lars H

2018-01-01

Innate immune cells play a well-documented role in the etiology and disease course of many brain-based conditions, including multiple sclerosis, Alzheimer's disease, traumatic brain and spinal cord injury, and brain cancers. In contrast, it is only recently becoming clear that innate immune cells, primarily brain resident macrophages called microglia, are also key regulators of brain development. This review summarizes the current state of knowledge regarding microglia in brain development, with particular emphasis on how microglia during development are distinct from microglia later in life. We also summarize the effects of early life perturbations on microglia function in the developing brain, the role that biological sex plays in microglia function, and the potential role that microglia may play in developmental brain disorders. Finally, given how new the field of developmental neuroimmunology is, we highlight what has yet to be learned about how innate immune cells shape the development of brain and behavior.

The emerging roles of Notch signaling in leukemia and stem cells

PubMed Central

2013-01-01

The Notch signaling pathway plays a critical role in maintaining the balance between cell proliferation, differentiation and apoptosis, and is a highly conserved signaling pathway that regulates normal development in a context- and dose-dependent manner. Dysregulation of Notch signaling has been suggested to be key events in a variety of hematological malignancies. Notch1 signaling appears to be the central oncogenic trigger in T cell acute lymphoblastic leukemia (T-ALL), in which the majority of human malignancies have acquired mutations that lead to constitutive activation of Notch1 signaling. However, emerging evidence unexpectedly demonstrates that Notch signaling can function as a potent tumor suppressor in other forms of leukemia. This minireview will summarize recent advances related to the roles of activated Notch signaling in human lymphocytic leukemia, myeloid leukemia, stem cells and stromal microenvironment, and we will discuss the perspectives of Notch signaling as a potential therapeutic target as well. PMID:24252593

MOR23 promotes muscle regeneration and regulates cell adhesion and migration

PubMed Central

Griffin, Christine A.; Kafadar, Kimberly A.; Pavlath, Grace K.

2009-01-01

Summary Odorant receptors (ORs) in the olfactory epithelium bind to volatile small molecules leading to the perception of smell. ORs are expressed in many tissues but their functions are largely unknown. We show multiple ORs display distinct mRNA expression patterns during myogenesis in vitro and muscle regeneration in vivo. Mouse OR23 (MOR23) expression is induced during muscle regeneration when muscle cells are extensively fusing and plays a key role in regulating migration and adhesion of muscle cells in vitro, two processes common during tissue repair. A soluble ligand for MOR23 is secreted by muscle cells in vitro and muscle tissue in vivo. MOR23 is necessary for proper skeletal muscle regeneration as loss of MOR23 leads to increased myofiber branching, commonly associated with muscular dystrophy. Together these data identify a functional role for an OR outside of the nose and suggest a larger role for ORs during tissue repair. PMID:19922870

Immunological modes of pregnancy loss: inflammation, immune effectors, and stress.

PubMed

Kwak-Kim, Joanne; Bao, Shihua; Lee, Sung Ki; Kim, Joon Woo; Gilman-Sachs, Alice

2014-08-01

Inflammatory immune response plays a key role in reproductive failures such as multiple implantation failures (MIF), early pregnancy loss, and recurrent pregnancy losses (RPL). Cellular immune responses particularly mediated by natural killer (NK), and T cells are often dysregulated in these conditions. Excessive or inappropriate recruitment of peripheral blood NK cells to the uterus may lead to cytotoxic environment in utero, in which proliferation and differentiation of trophoblast is hampered. In addition, inadequate angiogenesis by uterine NK cells often leads to abnormal vascular development and blood flow patterns, which, in turn, leads to increased oxidative stress or ischemic changes in the invading trophoblast. T-cell abnormalities with increased Th1 and Th17 immunity, and decreased Th2 and T regulatory immune responses may play important roles in RPL and MIF. A possible role of stress in inflammatory immune response is also reviewed. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cerebellar neurodegeneration in the absence of microRNAs

PubMed Central

Schaefer, Anne; O'Carroll, Dónal; Tan, Chan Lek; Hillman, Dean; Sugimori, Mutsuyuki; Llinas, Rodolfo; Greengard, Paul

2007-01-01

Genome-encoded microRNAs (miRNAs) are potent regulators of gene expression. The significance of miRNAs in various biological processes has been suggested by studies showing an important role of these small RNAs in regulation of cell differentiation. However, the role of miRNAs in regulation of differentiated cell physiology is not well established. Mature neurons express a large number of distinct miRNAs, but the role of miRNAs in postmitotic neurons has not been examined. Here, we provide evidence for an essential role of miRNAs in survival of differentiated neurons. We show that conditional Purkinje cell–specific ablation of the key miRNA-generating enzyme Dicer leads to Purkinje cell death. Deficiency in Dicer is associated with progressive loss of miRNAs, followed by cerebellar degeneration and development of ataxia. The progressive neurodegeneration in the absence of Dicer raises the possibility of an involvement of miRNAs in neurodegenerative disorders. PMID:17606634

Type 2 Innate Lymphoid Cells: Friends or Foes—Role in Airway Allergic Inflammation and Asthma

PubMed Central

Pishdadian, Abbas; Varasteh, Abdol-Reza; Sankian, Mojtaba

2012-01-01

Innate-like lymphocytes (ILLs) and innate lymphoid cells (ILCs) are two newly characterized families of lymphocytes with limited and no rearranged antigen receptors, respectively. These soldiers provide a first line of defense against foreign insults by triggering a prompt innate immune response and bridging the gap of innate and adaptive immunity. Type 2 innate lymphoid cells (ILCs2) are newly identified members of the ILC family that play a key role in type 2 immune responses by prompt production of type 2 cytokines (especially IL-5 and IL-13) in response to antigen-induced IL-25/33 and by recruiting type 2 “immune franchise.” Regarding the two different roles of type 2 cytokines, helminth expulsion and type 2-related diseases, here we review the latest advances in ILC2 biology and examine the pivotal role of resident ILCs2 in allergen-specific airway inflammation and asthma. PMID:23209480

Type 2 innate lymphoid cells: friends or foes-role in airway allergic inflammation and asthma.

PubMed

Pishdadian, Abbas; Varasteh, Abdol-Reza; Sankian, Mojtaba

2012-01-01

Innate-like lymphocytes (ILLs) and innate lymphoid cells (ILCs) are two newly characterized families of lymphocytes with limited and no rearranged antigen receptors, respectively. These soldiers provide a first line of defense against foreign insults by triggering a prompt innate immune response and bridging the gap of innate and adaptive immunity. Type 2 innate lymphoid cells (ILCs2) are newly identified members of the ILC family that play a key role in type 2 immune responses by prompt production of type 2 cytokines (especially IL-5 and IL-13) in response to antigen-induced IL-25/33 and by recruiting type 2 "immune franchise." Regarding the two different roles of type 2 cytokines, helminth expulsion and type 2-related diseases, here we review the latest advances in ILC2 biology and examine the pivotal role of resident ILCs2 in allergen-specific airway inflammation and asthma.

Nrf2/Keap1 system regulates vascular smooth muscle cell apoptosis for vascular homeostasis: role in neointimal formation after vascular injury

PubMed Central

Ashino, Takashi; Yamamoto, Masayuki; Numazawa, Satoshi

2016-01-01

Abnormal increases in vascular smooth muscle cells (VSMCs) in the intimal region after a vascular injury is a key event in developing neointimal hyperplasia. To maintain vascular function, proliferation and apoptosis of VSMCs is tightly controlled during vascular remodeling. NF-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) system, a key component of the oxidative stress response that acts in maintaining homeostasis, plays an important role in neointimal hyperplasia after a vascular injury; however, the role of Nrf2/Keap1 in VSMC apoptosis has not been clarified. Here we report that 14 days after arterial injury in mice, TUNEL-positive VSMCs are detected in both the neointimal and medial layers. These layers contain cells expressing high levels of Nrf2 but low Keap1 expression. In VSMCs, Keap1 depletion induces features of apoptosis, such as positive TUNEL staining and annexin V binding. These changes are associated with an increased expression of nuclear Nrf2. Simultaneous Nrf2 depletion inhibits Keap1 depletion-induced apoptosis. At 14 days after the vascular injury, Nrf2-deficient mice demonstrated fewer TUNEL-positive cells and increased neointimal formation in the neointimal and medial areas. The results suggest that the Nrf2/Keap1 system regulates VSMC apoptosis during neointimal formation, thereby inhibiting neointimal hyperplasia after a vascular injury. PMID:27198574

Aid is a key regulator of myeloid/erythroid differentiation and DNA methylation in hematopoietic stem/progenitor cells

PubMed Central

Kunimoto, Hiroyoshi; McKenney, Anna Sophia; Meydan, Cem; Shank, Kaitlyn; Nazir, Abbas; Rapaport, Franck; Durham, Benjamin; Garrett-Bakelman, Francine E.; Pronier, Elodie; Shih, Alan H.; Melnick, Ari; Chaudhuri, Jayanta

2017-01-01

Recent studies have reported that activation-induced cytidine deaminase (AID) and ten-eleven-translocation (TET) family members regulate active DNA demethylation. Genetic alterations of TET2 occur in myeloid malignancies, and hematopoietic-specific loss of Tet2 induces aberrant hematopoietic stem cell (HSC) self-renewal/differentiation, implicating TET2 as a master regulator of normal and malignant hematopoiesis. Despite the functional link between AID and TET in epigenetic gene regulation, the role of AID loss in hematopoiesis and myeloid transformation remains to be investigated. Here, we show that Aid loss in mice leads to expansion of myeloid cells and reduced erythroid progenitors resulting in anemia, with dysregulated expression of Cebpa and Gata1, myeloid/erythroid lineage-specific transcription factors. Consistent with data in the murine context, silencing of AID in human bone marrow cells skews differentiation toward myelomonocytic lineage. However, in contrast to Tet2 loss, Aid loss does not contribute to enhanced HSC self-renewal or cooperate with Flt3-ITD to induce myeloid transformation. Genome-wide transcription and differential methylation analysis uncover the critical role of Aid as a key epigenetic regulator. These results indicate that AID and TET2 share common effects on myeloid and erythroid lineage differentiation, however, their role is nonredundant in regulating HSC self-renewal and in myeloid transformation. PMID:28077417

New immune cells in spondyloarthritis: Key players or innocent bystanders?

PubMed

Venken, Koen; Elewaut, Dirk

2015-12-01

The central role of the inflammatory cytokines such as TNF-α, IL-23, and IL-17 in the disease pathogenesis of spondyloarthritis (SpA) is unquestionable, given the strong efficacy of anti-cytokine therapeutics used in the treatment of SpA patients. These cytokines are produced by a diverse range of immune cells, some extending beyond the typical spectrum of lineage-defined subsets. Recently, a number of specialized cells, such as innate-like T-cells, innate lymphoid cells (ILCs) and natural killer receptor (NKR)-expressing T cells, have been marked to be involved in SpA pathology. In this chapter, we will elaborate on the unique characteristics of these particular immune subsets and critically evaluate their potential contribution to SpA disease, taking into account their role in joint and gut pathology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intracellular Fluid Mechanics: Coupling Cytoplasmic Flow with Active Cytoskeletal Gel

NASA Astrophysics Data System (ADS)

Mogilner, Alex; Manhart, Angelika

2018-01-01

The cell is a mechanical machine, and continuum mechanics of the fluid cytoplasm and the viscoelastic deforming cytoskeleton play key roles in cell physiology. We review mathematical models of intracellular fluid mechanics, from cytoplasmic fluid flows, to the flow of a viscous active cytoskeletal gel, to models of two-phase poroviscous flows, to poroelastic models. We discuss application of these models to cell biological phenomena, such as organelle positioning, blebbing, and cell motility. We also discuss challenges of understanding fluid mechanics on the cellular scale.

Interferon regulatory factors: A key to tumour immunity.

PubMed

Chen, Yan-Jie; Li, Jing; Lu, Nan; Shen, Xi-Zhong

2017-08-01

Interferon regulatory factors (IRFs), which have 10 members, belong to the transcription factor family and were named because of the regulation of interferon expression. They play important roles in the immune regulation, cell differentiation, cell apoptosis, and cell cycle regulation. This article will review the functional characteristics and immune activity of the family members, especially in the role of cell differentiation and autoimmune diseases. Intensive studies will help uncover the pathogenesis of the disease in a more comprehensive view, and provide novel targets for disease treatment. But the most important problems yet to solve is IRFs function in the development processes of tumour, and whether IRFs can be an important regulator in tumour immune treatment. Copyright © 2017. Published by Elsevier B.V.

Hippo signaling controls cell cycle and restricts cell plasticity in planarians

PubMed Central

de Sousa, Nídia; Rodríguez-Esteban, Gustavo; Rojo-Laguna, Jose Ignacio; Saló, Emili

2018-01-01

The Hippo pathway plays a key role in regulating cell turnover in adult tissues, and abnormalities in this pathway are consistently associated with human cancers. Hippo was initially implicated in the control of cell proliferation and death, and its inhibition is linked to the expansion of stem cells and progenitors, leading to larger organ size and tumor formation. To understand the mechanism by which Hippo directs cell renewal and promotes stemness, we studied its function in planarians. These stem cell–based organisms are ideal models for the analysis of the complex cellular events underlying tissue renewal in the whole organism. hippo RNA interference (RNAi) in planarians decreased apoptotic cell death, induced cell cycle arrest, and could promote the dedifferentiation of postmitotic cells. hippo RNAi resulted in extensive undifferentiated areas and overgrowths, with no effect on body size or cell number. We propose an essential role for hippo in controlling cell cycle, restricting cell plasticity, and thereby preventing tumoral transformation. PMID:29357350

Effect of aging on stem cells

PubMed Central

Ahmed, Abu Shufian Ishtiaq; Sheng, Matilda HC; Wasnik, Samiksha; Baylink, David J; Lau, Kin-Hing William

2017-01-01

Pluripotent stem cells have the remarkable self-renewal ability and are capable of differentiating into multiple diverse cells. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging-associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging-associated diseases. This review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging-associated stem cell defects. PMID:28261550

Pericytes of the neurovascular unit: Key functions and signaling pathways

PubMed Central

Sweeney, Melanie D.; Ayyadurai, Shiva; Zlokovic, Berislav V.

2017-01-01

Pericytes are vascular mural cells embedded in the basement membrane of blood microvessels. They extend their processes along capillaries, pre-capillary arterioles, and post-capillary venules. The central nervous system (CNS) pericytes are uniquely positioned within the neurovascular unit between endothelial cells, astrocytes, and neurons. They integrate, coordinate, and process signals from their neighboring cells to generate diverse functional responses that are critical for CNS functions in health and disease including regulation of the blood-brain barrier permeability, angiogenesis, clearance of toxic metabolites, capillary hemodynamic responses, neuroinflammation, and stem cell activity. Here, we examine the key signaling pathways between pericytes and their neighboring endothelial cells, astrocytes, and neurons that control neurovascular functions. We also review the role of pericytes in different CNS disorders including rare monogenic diseases and complex neurological disorders such as Alzheimer's disease and brain tumors. Finally, we discuss directions for future studies. PMID:27227366

Molecular Memory of Morphologies by Septins during Neuron Generation Allows Early Polarity Inheritance.

PubMed

Boubakar, Leila; Falk, Julien; Ducuing, Hugo; Thoinet, Karine; Reynaud, Florie; Derrington, Edmund; Castellani, Valérie

2017-08-16

Transmission of polarity established early during cell lineage history is emerging as a key process guiding cell differentiation. Highly polarized neurons provide a fascinating model to study inheritance of polarity over cell generations and across morphological transitions. Neural crest cells (NCCs) migrate to the dorsal root ganglia to generate neurons directly or after cell divisions in situ. Using live imaging of vertebrate embryo slices, we found that bipolar NCC progenitors lose their polarity, retracting their processes to round for division, but generate neurons with bipolar morphology by emitting processes from the same locations as the progenitor. Monitoring the dynamics of Septins, which play key roles in yeast polarity, indicates that Septin 7 tags process sites for re-initiation of process growth following mitosis. Interfering with Septins blocks this mechanism. Thus, Septins store polarity features during mitotic rounding so that daughters can reconstitute the initial progenitor polarity. Copyright © 2017 Elsevier Inc. All rights reserved.

NFIB-mediated repression of the epigenetic factor Ezh2 regulates cortical development.

PubMed

Piper, Michael; Barry, Guy; Harvey, Tracey J; McLeay, Robert; Smith, Aaron G; Harris, Lachlan; Mason, Sharon; Stringer, Brett W; Day, Bryan W; Wray, Naomi R; Gronostajski, Richard M; Bailey, Timothy L; Boyd, Andrew W; Richards, Linda J

2014-02-19

Epigenetic mechanisms are essential in regulating neural progenitor cell self-renewal, with the chromatin-modifying protein Enhancer of zeste homolog 2 (EZH2) emerging as a central player in promoting progenitor cell self-renewal during cortical development. Despite this, how Ezh2 is itself regulated remains unclear. Here, we demonstrate that the transcription factor nuclear factor IB (NFIB) plays a key role in this process. Nfib(-/-) mice exhibit an increased number of proliferative ventricular zone cells that express progenitor cell markers and upregulation of EZH2 expression within the neocortex and hippocampus. NFIB binds to the Ezh2 promoter and overexpression of NFIB represses Ezh2 transcription. Finally, key downstream targets of EZH2-mediated epigenetic repression are misregulated in Nfib(-/-) mice. Collectively, these results suggest that the downregulation of Ezh2 transcription by NFIB is an important component of the process of neural progenitor cell differentiation during cortical development.

The Role of RNA in Biological Phase Separations.

PubMed

Fay, Marta M; Anderson, Paul J

2018-05-10

Phase transitions that alter the physical state of ribonucleoprotein particles contribute to the spacial and temporal organization of the densely packed intracellular environment. This allows cells to organize biologically coupled processes as well as respond to environmental stimuli. RNA plays a key role in phase separation events that modulate various aspects of RNA metabolism. Here, we review the role that RNA plays in ribonucleoprotein phase separations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake

PubMed Central

Li, Wei; Podar, Mircea

2016-01-01

ABSTRACT The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activated cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (Flavobacteria and Methylobacteriaceae) were independently associated with two key MCM lake microalgae (Isochrysis and Chlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite of Chlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake. IMPORTANCE Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment. PMID:27084010

Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake.

PubMed

Li, Wei; Podar, Mircea; Morgan-Kiss, Rachael M

2016-06-15

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activated cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (Flavobacteria and Methylobacteriaceae) were independently associated with two key MCM lake microalgae (Isochrysis and Chlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite of Chlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake. Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake

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

Li, Wei; Podar, Mircea; Morgan-Kiss, Rachael M.

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activatedmore » cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (FlavobacteriaandMethylobacteriaceae) were independently associated with two key MCM lake microalgae (IsochrysisandChlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite ofChlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake. Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Ultimately, our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment.« less

Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake

DOE PAGES

Li, Wei; Podar, Mircea; Morgan-Kiss, Rachael M.

2016-04-15

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activatedmore » cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (FlavobacteriaandMethylobacteriaceae) were independently associated with two key MCM lake microalgae (IsochrysisandChlamydomonas, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite ofChlamydomonas, a dominate primary producer in the shallow, nutrient-poor layers of the lake. Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Ultimately, our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment.« less

The Transcription Factor Bright Plays a Role in Marginal Zone B Lymphocyte Development and Autoantibody Production

PubMed Central

Oldham, Athenia L.; Miner, Cathrine A.; Wang, Hong-Cheng; Webb, Carol F.

2011-01-01

Previous data suggested that constitutive expression of the transcription factor Bright (B cell regulator of immunoglobulin heavy chain transcription), normally tightly regulated during B cell differentiation, was associated with autoantibody production. Here we show that constitutive Bright expression results in skewing of mature B lineage subpopulations toward marginal zone cells at the expense of the follicular subpopulation. C57Bl/6 transgenic mice constitutively expressing Bright in B lineage cells generated autoantibodies that were not the result of global increases in immunoglobulin or of breaches in key tolerance checkpoints typically defective in other autoimmune mouse models. Rather, autoimmunity correlated with increased numbers of marginal zone B cells and alterations in the phenotype and gene expression profiles of lymphocytes within the follicular B cell compartment. These data suggest a novel role for Bright in the normal development of mature B cell subsets and in autoantibody production. PMID:21963220

Viral Evasion of Natural Killer Cell Activation

PubMed Central

Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

2016-01-01

Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections. PMID:27077876

Viral Evasion of Natural Killer Cell Activation.

PubMed

Ma, Yi; Li, Xiaojuan; Kuang, Ersheng

2016-04-12

Natural killer (NK) cells play a key role in antiviral innate defenses because of their abilities to kill infected cells and secrete regulatory cytokines. Additionally, NK cells exhibit adaptive memory-like antigen-specific responses, which represent a novel antiviral NK cell defense mechanism. Viruses have evolved various strategies to evade the recognition and destruction by NK cells through the downregulation of the NK cell activating receptors. Here, we review the recent findings on viral evasion of NK cells via the impairment of NK cell-activating receptors and ligands, which provide new insights on the relationship between NK cells and viral actions during persistent viral infections.

Novel role of MDA-9/syntenin in regulating urothelial cell proliferation by modulating EGFR signaling.

PubMed

Dasgupta, Santanu; Menezes, Mitchell E; Das, Swadesh K; Emdad, Luni; Janjic, Aleksandar; Bhatia, Shilpa; Mukhopadhyay, Nitai D; Shao, Chunbo; Sarkar, Devanand; Fisher, Paul B

2013-09-01

Urothelial cell carcinoma (UCC) rapidly progresses from superficial to muscle-invasive tumors. The key molecules involved in metastatic progression and its early detection require clarification. The present study defines a seminal role of the metastasis-associated gene MDA-9/Syntenin in UCC progression. Expression pattern of MDA-9/Syntenin was examined in 44 primary UCC and the impact of its overexpression and knockdown was examined in multiple cells lines and key findings were validated in primary tumors. Significantly higher (P=0.002-0.003) expression of MDA-9/Syntenin was observed in 64% (28 of 44) of primary tumors and an association was evident with stage (P=0.01), grade (P=0.03), and invasion status (P=0.02). MDA-9/Syntenin overexpression in nontumorigenic HUC-1 cells increased proliferation (P=0.0012), invasion (P=0.0001), and EGF receptor (EGFR), AKT, phosphoinositide 3-kinase (PI3K), and c-Src expression. Alteration of β-catenin, E-cadherin, vimentin, claudin-1, ZO-1, and T-cell factor-4 (TCF4) expression was also observed. MDA-9/Syntenin knockdown in three UCC cell lines reversed phenotypic and molecular changes observed in the HUC-1 cells and reduced in vivo metastasis. Key molecular changes observed in the cell lines were confirmed in primary tumors. A physical interaction and colocalization of MDA-9/Syntenin and EGFR was evident in UCC cell lines and primary tumors. A logistic regression model analysis revealed a significant correlation between MDA-9/Syntenin:EGFR and MDA-9/Syntenin:AKT expressions with stage (P=0.04, EGFR; P=0.01, AKT). A correlation between MDA-9/Syntenin:β-catenin coexpression with stage (P=0.03) and invasion (P=0.04) was also evident. Our findings indicate that MDA-9/Syntenin might provide an attractive target for developing detection, monitoring, and therapeutic strategies for managing UCC. ©2013 AACR.

Role of asymmetric cell division in lifespan control in Saccharomyces cerevisiae

PubMed Central

Higuchi-Sanabria, Ryo; Pernice, Wolfgang M A; Vevea, Jason D; Alessi Wolken, Dana M; Boldogh, Istvan R; Pon, Liza A

2014-01-01

Aging determinants are asymmetrically distributed during cell division in S. cerevisiae, which leads to production of an immaculate, age-free daughter cell. During this process, damaged components are sequestered and retained in the mother cell, and higher functioning organelles and rejuvenating factors are transported to and/or enriched in the bud. Here, we will describe the key quality control mechanisms in budding yeast that contribute to asymmetric cell division of aging determinants including mitochondria, endoplasmic reticulum (ER), vacuoles, extrachromosomal rDNA circles (ERCs), and protein aggregates. PMID:25263578

E-cadherin in contact inhibition and cancer.

PubMed

Mendonsa, Alisha M; Na, Tae-Young; Gumbiner, Barry M

2018-05-21

E-cadherin is a key component of the adherens junctions that are integral in cell adhesion and maintaining epithelial phenotype of cells. Homophilic E-cadherin binding between cells is important in mediating contact inhibition of proliferation when cells reach confluence. Loss of E-cadherin expression results in loss of contact inhibition and is associated with increased cell motility and advanced stages of cancer. In this review we discuss the role of E-cadherin and its downstream signaling in regulation of contact inhibition and the development and progression of cancer.

Induction and function of virus-specific CD4+ T cell responses

PubMed Central

Whitmire, Jason K.

2010-01-01

CD4+ T cells -- often referred to as T-helper cells -- play a central role in immune defense and pathogenesis. Virus infections and vaccines stimulate and expand populations of antigen-specific CD4+ T cells in mice and in man. These virus-specific CD4+ T cells are extremely important in antiviral protection: deficiencies in CD4+ T cells are associated with virus reactivation, generalized susceptibility to opportunistic infections, and poor vaccine efficacy. As described below, CD4+ T cells influence effector and memory CD8+ T cell responses, humoral immunity, and the antimicrobial activity of macrophages and are involved in recruiting cells to sites of infection. This review summarizes a few key points about the dynamics of the CD4+ T cell response to virus infection, the positive role of pro-inflammatory cytokines in the differentiation of virus-specific CD4+ T cells, and new areas of investigation to improve vaccines against virus infection. PMID:21236461

Host Gene Expression Analysis in Sri Lankan Melioidosis Patients

DTIC Science & Technology

2017-06-19

response genes and epigenetic regulators during melioidosis infection. Methods Patient enrollment Nationwide active surveillance for melioidosis... activator complex subunit 2 TR-17-140 Distribution Statement A: Approved for public release; distribution is unlimited. 13 PSMA5 Proteasome subunit...B-cell activation and T-cell proliferation, thus acting as a key regulator of humoral and adaptive immunity. Its role as an anti-inflammatory

Depletion of elongation initiation factor 4E binding proteins by CRISPR/Cas9 genome editing enhances antiviral response in porcine cells

USDA-ARS?s Scientific Manuscript database

Type I interferons (IFN) are key mediators of the innate antiviral response in mammalian cells. Elongation initiation factor 4E binding proteins (4E-BPs) are translational controllers of interferon regulatory factor 7 (IRF7), the master regulator of IFN transcription. The role of 4EBPs in the negat...

A key role for mitochondria in endothelial signaling by plasma cysteine/cystine redox potential

PubMed Central

Go, Young-Mi; Park, Heonyong; Koval, Michael; Orr, Michael; Reed, Matthew; Liang, Yongliang; Smith, Debra; Pohl, Jan; Jones, Dean P.

2011-01-01

The redox potential of the plasma cysteine/cystine couple (EhCySS) is oxidized in association with risk factors for cardiovascular disease (CVD), including age, smoking, type 2 diabetes, obesity, and alcohol abuse. Previous in vitro findings support a cause–effect relationship for extracellular EhCySS in cell signaling pathways associated with CVD, including those controlling monocyte adhesion to endothelial cells. In this study, we provide evidence that mitochondria are a major source of reactive oxygen species (ROS) in the signaling response to a more oxidized extracellular EhCySS. This increase in ROS was blocked by overexpression of mitochondrial thioredoxin-2 (Trx2) in endothelial cells from Trx2-transgenic mice, suggesting that mitochondrial thiol antioxidant status plays a key role in this redox signaling mechanism. Mass spectrometry-based redox proteomics showed that several classes of plasma membrane and cytoskeletal proteins involved in inflammation responded to this redox switch, including vascular cell adhesion molecule, integrins, actin, and several Ras family GTPases. Together, the data show that the proinflammatory effects of oxidized plasma EhCySS are due to a mitochondrial signaling pathway that is mediated through redox control of downstream effector proteins. PMID:19879942

Pursuing Intracellular Pathogens with Hyaluronan. From a 'Pro-Infection' Polymer to a Biomaterial for 'Trojan Horse' Systems.

PubMed

Montanari, Elita; Di Meo, Chiara; Oates, Angela; Coviello, Tommasina; Matricardi, Pietro

2018-04-18

Hyaluronan (HA) is among the most important bioactive polymers in mammals, playing a key role in a number of biological functions. In the last decades, it has been increasingly studied as a biomaterial for drug delivery systems, thanks to its physico-chemical features and ability to target and enter certain cells. The most important receptor of HA is ‘Cluster of Differentiation 44’ (CD44), a cell surface glycoprotein over-expressed by a number of cancers and heavily involved in HA endocytosis. Moreover, CD44 is highly expressed by keratinocytes, activated macrophages and fibroblasts, all of which can act as ‘reservoirs’ for intracellular pathogens. Interestingly, both CD44 and HA appear to play a key role for the invasion and persistence of such microorganisms within the cells. As such, HA is increasingly recognised as a potential target for nano-carriers development, to pursuit and target intracellular pathogens, acting as a ‘Trojan Horse’. This review describes the biological relationship between HA, CD44 and the entry and survival of a number of pathogens within the cells and the subsequent development of HA-based nano-carriers for enhancing the intracellular activity of antimicrobials.

Role for early-differentiated natural killer cells in infectious mononucleosis

PubMed Central

Azzi, Tarik; Lünemann, Anna; Murer, Anita; Ueda, Seigo; Béziat, Vivien; Malmberg, Karl-Johan; Staubli, Georg; Gysin, Claudine; Berger, Christoph; Münz, Christian

2014-01-01

A growing body of evidence suggests that the human natural killer (NK)-cell compartment is phenotypically and functionally heterogeneous and is composed of several differentiation stages. Moreover, NK-cell subsets have been shown to exhibit adaptive immune features during herpes virus infection in experimental mice and to expand preferentially during viral infections in humans. However, both phenotype and role of NK cells during acute symptomatic Epstein-Barr virus (EBV) infection, termed infectious mononucleosis (IM), remain unclear. Here, we longitudinally assessed the kinetics, the differentiation, and the proliferation of subsets of NK cells in pediatric IM patients. Our results indicate that acute IM is characterized by the preferential proliferation of early-differentiated CD56dim NKG2A+ immunoglobulin-like receptor- NK cells. Moreover, this NK-cell subset exhibits features of terminal differentiation and persists at higher frequency during at least the first 6 months after acute IM. Finally, we demonstrate that this NK-cell subset preferentially degranulates and proliferates on exposure to EBV-infected B cells expressing lytic antigens. Thus, early-differentiated NK cells might play a key role in the immune control of primary infection with this persistent tumor-associated virus. PMID:25205117

Role for early-differentiated natural killer cells in infectious mononucleosis.

PubMed

Azzi, Tarik; Lünemann, Anna; Murer, Anita; Ueda, Seigo; Béziat, Vivien; Malmberg, Karl-Johan; Staubli, Georg; Gysin, Claudine; Berger, Christoph; Münz, Christian; Chijioke, Obinna; Nadal, David

2014-10-16

A growing body of evidence suggests that the human natural killer (NK)-cell compartment is phenotypically and functionally heterogeneous and is composed of several differentiation stages. Moreover, NK-cell subsets have been shown to exhibit adaptive immune features during herpes virus infection in experimental mice and to expand preferentially during viral infections in humans. However, both phenotype and role of NK cells during acute symptomatic Epstein-Barr virus (EBV) infection, termed infectious mononucleosis (IM), remain unclear. Here, we longitudinally assessed the kinetics, the differentiation, and the proliferation of subsets of NK cells in pediatric IM patients. Our results indicate that acute IM is characterized by the preferential proliferation of early-differentiated CD56(dim) NKG2A(+) immunoglobulin-like receptor(-) NK cells. Moreover, this NK-cell subset exhibits features of terminal differentiation and persists at higher frequency during at least the first 6 months after acute IM. Finally, we demonstrate that this NK-cell subset preferentially degranulates and proliferates on exposure to EBV-infected B cells expressing lytic antigens. Thus, early-differentiated NK cells might play a key role in the immune control of primary infection with this persistent tumor-associated virus. © 2014 by The American Society of Hematology.

Expression and localization of insulin-like growth factor system in corpus luteum during different stages of estrous cycle in water buffaloes (Bubalus bubalis) and the effect of insulin-like growth factor I on production of vascular endothelial growth factor and progesterone in luteal cells cultured in vitro.

PubMed

Uniyal, S; Panda, R P; Chouhan, V S; Yadav, V P; Hyder, I; Dangi, S S; Gupta, M; Khan, F A; Sharma, G T; Bag, S; Sarkar, M

2015-01-01

This study investigated the expression and localization of insulin-like growth factor (IGF) system at different stages of buffalo CL and the role of IGF-I in stimulating vascular endothelial growth factor (VEGF) and progesterone (P4) production in cultured luteal cells. The mRNA expression of IGF system, VEGF, steroidogenic acute regulatory protein, P450scc, and hydroxysteroid dehydrogenase (HSD) was investigated by quantitative real-time polymerase chain reaction (PCR). Protein expression of IGF was demonstrated by Western blot and localization by immunohistochemistry. Progesterone and VEGF production was assayed using RIA and ELISA. A relatively high mRNA expression of IGF-I and IGF-II in early, mid- and late luteal phases with immunoreactivity mostly restricted to cytoplasm of large luteal cells indicates their autocrine role, whereas very weak immunoreactivity in endothelial cells during the mid-luteal phase indicates their paracrine role. Insulin-like growth factor receptors, IGF-IR and IGF-IIR, were restricted to large luteal cells with high mRNA and protein expressions in the mid-luteal phase. The significantly higher expression of insulin-like growth factor binding protein (IGFBP)-1, -3, -5, and -6 in the early or mid-luteal phase suggested their stimulatory role, whereas that of IGFBP-2 and -4 in mid-, late, and regressive luteal stages implied their inhibitory role. The mRNA expressions of key steroidogenic factors and VEGF were significantly higher (P < 0.05) when the culture medium was supplemented with 100 ng/mL of IGF-I for 72 hours. Moreover, IGF-I at a dose of 100 ng/mL increased P4 and VEGF production (P < 0.05). It can be concluded that IGF family members via their autocrine and paracrine effect play significant roles in promoting angiogenesis through the production of VEGF in luteal cells and steroid synthesis through the production of key steroidogenic factors. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunology and Immunotherapy of Head and Neck Cancer

PubMed Central

Ferris, Robert L.

2015-01-01

The immune system plays a key role in the development, establishment, and progression of head and neck squamous cell carcinoma (HNSCC). A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of HNSCC provides the basis for improved therapies and outcomes for patients. HNSCC cells evade the host immune system through manipulation of their own immunogenicity, production of immunosuppressive mediators, and promotion of immunomodulatory cell types. Through the tumor's influence on the microenvironment, the immune system can be exploited to promote metastasis, angiogenesis, and growth. This article provides a brief overview of key components of the immune infiltrating cells in the tumor microenvironment, reviewing immunological principles related to head and neck cancer, including the concept of cancer immunosurveillance and immune escape. Current immunotherapeutic strategies and emerging results from ongoing clinical trials are presented. PMID:26351330

Neuroinflammation in Parkinson's disease: role in neurodegeneration and tissue repair.

PubMed

Vivekanantham, Sayinthen; Shah, Savan; Dewji, Rizwan; Dewji, Abbas; Khatri, Chetan; Ologunde, Rele

2015-01-01

Neuroinflammation in Parkinson's disease [PD] is a process that occurs alongside the loss of dopaminergic neurons, and is associated with alterations to many cell types, most notably microglia. This review examines the key evidence contributing to our understanding of the role of inflammation-mediated degeneration of the dopaminergic (DA) nigrostriatal pathway in PD. It will consider the potential role inflammation plays in tissue repair within the brain, inflammation linked gene products that are associated with sporadic Parkinsonian phenotypes (alpha-synuclein, Parkin and Nurr 1), and developing anti-inflammatory drug treatments in PD. With growing evidence supporting the key role of neuroinflammation in PD pathogenesis, new molecular targets are being found that could potentially prevent or delay nigrostriatal DA neuron loss. Hence, this creates the opportunity for disease modifying treatment, to currently what is an incurable disease.

Constitutive BAK activation as a determinant of drug sensitivity in malignant lymphohematopoietic cells

PubMed Central

Dai, Haiming; Ding, Husheng; Meng, X. Wei; Peterson, Kevin L.; Schneider, Paula A.; Karp, Judith E.; Kaufmann, Scott H.

2015-01-01

Mitochondrial outer membrane permeabilization (MOMP), a key step in the intrinsic apoptotic pathway, is incompletely understood. Current models emphasize the role of BH3-only BCL2 family members in BAX and BAK activation. Here we demonstrate concentration-dependent BAK autoactivation under cell-free conditions and provide evidence that this autoactivation plays a key role in regulating the intrinsic apoptotic pathway in intact cells. In particular, we show that up to 80% of BAK (but not BAX) in lymphohematopoietic cell lines is oligomerized and bound to anti-apoptotic BCL2 family members in the absence of exogenous death stimuli. The extent of this constitutive BAK oligomerization is diminished by BAK knockdown and unaffected by BIM or PUMA down-regulation. Further analysis indicates that sensitivity of cells to BH3 mimetics reflects the identity of the anti-apoptotic proteins to which BAK is constitutively bound, with extensive BCLXL•BAK complexes predicting navitoclax sensitivity, and extensive MCL1•BAK complexes predicting A1210477 sensitivity. Moreover, high BAK expression correlates with sensitivity of clinical acute myelogenous leukemia to chemotherapy, whereas low BAK levels correlate with resistance and relapse. Collectively, these results inform current understanding of MOMP and provide new insight into the ability of BH3 mimetics to induce apoptosis without directly activating BAX or BAK. PMID:26494789

Absence of autophagy results in reactive oxygen species-dependent amplification of RLR signaling

PubMed Central

Tal, Michal Caspi; Sasai, Miwa; Lee, Heung Kyu; Yordy, Brian; Shadel, Gerald S.; Iwasaki, Akiko

2009-01-01

Autophagy is a highly conserved process that maintains homeostasis by clearing damaged organelles and long-lived proteins. The consequences of deficiency in autophagy manifest in a variety of pathological states including neurodegenerative diseases, inflammatory disorders, and cancer. Here, we studied the role of autophagy in the homeostatic regulation of innate antiviral defense. Single-stranded RNA viruses are recognized by the members of the RIG-I-like receptors (RLRs) in the cytosol. RLRs signal through IPS-1, resulting in the production of the key antiviral cytokines, type I IFNs. Autophagy-defective Atg5−/− cells exhibited enhanced RLR signaling, increased IFN secretion, and resistance to infection by vesicular stomatitis virus. In the absence of autophagy, cells accumulated dysfunctional mitochondria, as well as mitochondria-associated IPS-1. Reactive oxygen species (ROS) associated with the dysfunctional mitochondria were largely responsible for the enhanced RLR signaling in Atg5−/− cells, as antioxidant treatment blocked the excess RLR signaling. In addition, autophagy-independent increase in mitochondrial ROS by treatment of cells with rotenone was sufficient to amplify RLR signaling in WT cells. These data indicate that autophagy contributes to homeostatic regulation of innate antiviral defense through the clearance of dysfunctional mitochondria, and revealed that ROS associated with mitochondria play a key role in potentiating RLR signaling. PMID:19196953

Card9-dependent IL-1β regulates IL-22 production from group 3 innate lymphoid cells and promotes colitis-associated cancer.

PubMed

Bergmann, Hanna; Roth, Susanne; Pechloff, Konstanze; Kiss, Elina A; Kuhn, Sabine; Heikenwälder, Mathias; Diefenbach, Andreas; Greten, Florian R; Ruland, Jürgen

2017-08-01

Inflammatory bowel diseases (IBD) are key risk factors for the development of colorectal cancer, but the mechanisms that link intestinal inflammation with carcinogenesis are insufficiently understood. Card9 is a myeloid cell-specific signaling protein that regulates inflammatory responses downstream of various pattern recognition receptors and which cooperates with the inflammasomes for IL-1β production. Because polymorphisms in Card9 were recurrently associated with human IBD, we investigated the function of Card9 in a colitis-associated cancer (CAC) model. Card9 -/- mice develop smaller, less proliferative and less dysplastic tumors compared to their littermates and in the regenerating mucosa we detected dramatically impaired IL-1β generation and defective IL-1β controlled IL-22 production from group 3 innate lymphoid cells. Consistent with the key role of immune-derived IL-22 in activating STAT3 signaling during normal and pathological intestinal epithelial cell (IEC) proliferation, Card9 -/- mice also exhibit impaired tumor cell intrinsic STAT3 activation. Our results imply a Card9-controlled, ILC3-mediated mechanism regulating healthy and malignant IEC proliferation and demonstrates a role of Card9-mediated innate immunity in inflammation-associated carcinogenesis. © 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

miR-133 is a key negative regulator of CDC42-PAK pathway in gastric cancer.

PubMed

Cheng, Zhenguo; Liu, Funan; Wang, Guanqiao; Li, Yanshu; Zhang, Hongyan; Li, Feng

2014-12-01

Cell division cycle 42 (CDC42), an important member of the Ras homolog (Rho) family, plays a key role in regulating multiple cellular processes such as cell cycle progression, migration, cell cytoskeleton organization, cell fate determination and differentiation. Among the downstream effectors of CDC42, P21-activated kinases (PAKs) obtain the most attention. Although a large body of evidence indicates that CDC42/PAKs pathway plays important role in tumor growth, invasion and metastasis, the mechanism of their negative regulation remains unclear. Here, we identified CDC42, a PAKs activating factor, was a target of miR-133. Ectopic overexpression of miRNAs not only downregulated CDC42 expression and PAKs activation, but also inhibited cancer cell proliferation and migration. We also found that miR-133 was down-regulated in 180 pairs gastric cancer tissues. miR-133 expression was negatively associated with tumor size, invasion depth and peripheral organ metastasis. Besides, dysfunction of miR-133 was an independent prognosis factor for overall survival. Our findings could provide new insights into the molecular mechanisms of gastric carcinogenesis, and may help facilitating development of CDC42/PAK-based therapies for human cancer. Copyright © 2014 Elsevier Inc. All rights reserved.

Epigenetic regulation of hematopoietic stem cell aging

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

Beerman, Isabel, E-mail: isabel.beerman@childrens.harvard.edu; Department of Pediatrics, Harvard Medical School, Boston, MA 02115; Program in Cellular and Molecular Medicine, Division of Hematology/Oncology, Boston Children's Hospital, MA 02116

2014-12-10

Aging is invariably associated with alterations of the hematopoietic stem cell (HSC) compartment, including loss of functional capacity, altered clonal composition, and changes in lineage contribution. Although accumulation of DNA damage occurs during HSC aging, it is unlikely such consistent aging phenotypes could be solely attributed to changes in DNA integrity. Another mechanism by which heritable traits could contribute to the changes in the functional potential of aged HSCs is through alterations in the epigenetic landscape of adult stem cells. Indeed, recent studies on hematopoietic stem cells have suggested that altered epigenetic profiles are associated with HSC aging and playmore » a key role in modulating the functional potential of HSCs at different stages during ontogeny. Even small changes of the epigenetic landscape can lead to robustly altered expression patterns, either directly by loss of regulatory control or through indirect, additive effects, ultimately leading to transcriptional changes of the stem cells. Potential drivers of such changes in the epigenetic landscape of aged HSCs include proliferative history, DNA damage, and deregulation of key epigenetic enzymes and complexes. This review will focus largely on the two most characterized epigenetic marks – DNA methylation and histone modifications – but will also discuss the potential role of non-coding RNAs in regulating HSC function during aging.« less

Sex and hedgehog: roles of genes in the hedgehog signaling pathway in mammalian sexual differentiation.

PubMed

Franco, Heather L; Yao, Humphrey H-C

2012-01-01

The chromosome status of the mammalian embryo initiates a multistage process of sexual development in which the bipotential reproductive system establishes itself as either male or female. These events are governed by intricate cell-cell and interorgan communication that is regulated by multiple signaling pathways. The hedgehog signaling pathway was originally identified for its key role in the development of Drosophila, but is now recognized as a critical developmental regulator in many species, including humans. In addition to its developmental roles, the hedgehog signaling pathway also modulates adult organ function, and misregulation of this pathway often leads to diseases, such as cancer. The hedgehog signaling pathway acts through its morphogenetic ligands that signal from ligand-producing cells to target cells over a specified distance. The target cells then respond in a graded manner based on the concentration of the ligands that they are exposed to. Through this unique mechanism of action, the hedgehog signaling pathway elicits cell fate determination, epithelial-mesenchymal interactions, and cellular homeostasis. Here, we review current findings on the roles of hedgehog signaling in the sexually dimorphic development of the reproductive organs with an emphasis on mammals and comparative evidence in other species.

IL-33: biological properties, functions, and roles in airway disease.

PubMed

Drake, Li Yin; Kita, Hirohito

2017-07-01

Interleukin (IL)-33 is a key cytokine involved in type 2 immunity and allergic airway diseases. Abundantly expressed in lung epithelial cells, IL-33 plays critical roles in both innate and adaptive immune responses in mucosal organs. In innate immunity, IL-33 and group 2 innate lymphoid cells (ILC2s) provide an essential axis for rapid immune responses and tissue homeostasis. In adaptive immunity, IL-33 interacts with dendritic cells, Th2 cells, follicular T cells, and regulatory T cells, where IL-33 influences the development of chronic airway inflammation and tissue remodeling. The clinical findings that both the IL-33 and ILC2 levels are elevated in patients with allergic airway diseases suggest that IL-33 plays an important role in the pathogenesis of these diseases. IL-33 and ILC2 may also serve as biomarkers for disease classification and to monitor the progression of diseases. In this article, we reviewed the current knowledge of the biology of IL-33 and discussed the roles of the IL-33 in regulating airway immune responses and allergic airway diseases. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Catalase-Modulated Heterogeneous Fenton Reaction for Selective Cancer Cell Eradication: SnFe2O4 Nanocrystals as an Effective Reagent for Treating Lung Cancer Cells.

PubMed

Lee, Kuan-Ting; Lu, Yu-Jen; Mi, Fwu-Long; Burnouf, Thierry; Wei, Yi-Ting; Chiu, Shao-Chieh; Chuang, Er-Yuan; Lu, Shih-Yuan

2017-01-18

Heterogeneous Fenton reactions have been proven to be an effective and promising selective cancer cell treatment method. The key working mechanism for this method to achieve the critical therapeutic selectivity however remains unclear. In this study, we proposed and demonstrated for the first time the critical role played by catalase in realizing the therapeutic selectivity for the heterogeneous Fenton reaction-driven cancer cell treatment. The heterogeneous Fenton reaction, with the lattice ferric ions of the solid catalyst capable of converting H 2 O 2 to highly reactive hydroxyl radicals, can effectively eradicate cancer cells. In this study, SnFe 2 O 4 nanocrystals, a recently discovered outstanding heterogeneous Fenton catalyst, were applied for selective killing of lung cancer cells. The SnFe 2 O 4 nanocrystals, internalized into the cancer cells, can effectively convert endogenous H 2 O 2 into highly reactive hydroxyl radicals to invoke an intensive cytotoxic effect on the cancer cells. On the other hand, catalase, present at a significantly higher concentration in normal cells than in cancer cells, remarkably can impede the apoptotic cell death induced by the internalized SnFe 2 O 4 nanocrystals. According to the results obtained from the in vitro cytotoxicity study, the relevant oxidative attacks were effectively suppressed by the presence of normal physiological levels of catalase. The SnFe 2 O 4 nanocrystals were thus proved to effect apoptotic cancer cell death through the heterogeneous Fenton reaction and were benign to cells possessing normal physiological levels of catalase. The catalase modulation of the involved heterogeneous Fenton reaction plays the key role in achieving selective cancer cell eradication for the heterogeneous Fenton reaction-driven cancer cell treatment.

Hepatocytes and IL-15: a favorable microenvironment for T cell survival and CD8+ T cell differentiation.

PubMed

Correia, Margareta P; Cardoso, Elsa M; Pereira, Carlos F; Neves, Rui; Uhrberg, Markus; Arosa, Fernando A

2009-05-15

Human intrahepatic lymphocytes are enriched in CD1d-unrestricted T cells coexpressing NKR. Although the origin of this population remains controversial, it is possible to speculate that the hepatic microenvironment, namely epithelial cells or the cytokine milieu, may play a role in its shaping. IL-15 is constitutively expressed in the liver and has a key role in activation and survival of innate and tissue-associated immune cells. In this in vitro study, we examined whether hepatocyte cell lines and/or IL-15 could play a role in the generation of NK-like T cells. The results show that both HepG2 cells and a human immortalized hepatocyte cell line increase survival and drive basal proliferation of T cells. In addition, IL-15 was capable of inducing Ag-independent up-regulation of NKR, including NKG2A, Ig-like receptors, and de novo expression of CD56 and NKp46 in CD8(+)CD56(-) T cells. In conclusion, our study suggests that hepatocytes and IL-15 create a favorable microenvironment for T cells to growth and survive. It can be proposed that the increased percentage of intrahepatic nonclassical NKT cells could be in part due to a local CD8(+) T cell differentiation.

Targeting protein kinase-b3 (akt3) signaling in melanoma.

PubMed

Madhunapantula, SubbaRao V; Robertson, Gavin P

2017-03-01

Deregulated Akt activity leading to apoptosis inhibition, enhanced proliferation and drug resistance has been shown to be responsible for 35-70% of advanced metastatic melanomas. Of the three isoforms, the majority of melanomas have elevated Akt3 expression and activity. Hence, potent inhibitors targeting Akt are urgently required, which is possible only if (a) the factors responsible for the failure of Akt inhibitors in clinical trials is known; and (b) the information pertaining to synergistically acting targeted therapeutics is available. Areas covered: This review provides a brief introduction of the PI3K-Akt signaling pathway and its role in melanoma development. In addition, the functional role of key Akt pathway members such as PRAS40, GSK3 kinases, WEE1 kinase in melanoma development are discussed together with strategies to modulate these targets. Efficacy and safety of Akt inhibitors is also discussed. Finally, the mechanism(s) through which Akt leads to drug resistance is discussed in this expert opinion review. Expert opinion: Even though Akt play key roles in melanoma tumor progression, cell survival and drug resistance, many gaps still exist that require further understanding of Akt functions, especially in the (a) metastatic spread; (b) circulating melanoma cells survival; and (c) melanoma stem cells growth.

Emerging Roles for Eosinophils in the Tumor Microenvironment.

PubMed

Reichman, Hadar; Karo-Atar, Danielle; Munitz, Ariel

2016-11-01

Eosinophils are evolutionary conserved cells largely studied in the context of allergy. Although eosinophils were first described in tumors more than 120 years ago, their roles in cancer are often overlooked. This is puzzling given their potent immune modulatory, cytotoxic, and/or tissue repair capabilities, and recent studies demonstrating key roles for eosinophils in contexts far beyond their 'classical' field (e.g., metabolism, thermogenesis, and tissue regeneration). Recent data suggest that this frequently ignored cell is emerging as a potent immune effector and immune modulator in the tumor microenvironment. This review discusses the relevance of eosinophils to tumorigenesis and the potential to harness their function in cancer therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

The Ser/Thr Protein Kinase Protein-Protein Interaction Map of M. tuberculosis.

PubMed

Wu, Fan-Lin; Liu, Yin; Jiang, He-Wei; Luan, Yi-Zhao; Zhang, Hai-Nan; He, Xiang; Xu, Zhao-Wei; Hou, Jing-Li; Ji, Li-Yun; Xie, Zhi; Czajkowsky, Daniel M; Yan, Wei; Deng, Jiao-Yu; Bi, Li-Jun; Zhang, Xian-En; Tao, Sheng-Ce

2017-08-01

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, the leading cause of death among all infectious diseases. There are 11 eukaryotic-like serine/threonine protein kinases (STPKs) in Mtb, which are thought to play pivotal roles in cell growth, signal transduction and pathogenesis. However, their underlying mechanisms of action remain largely uncharacterized. In this study, using a Mtb proteome microarray, we have globally identified the binding proteins in Mtb for all of the STPKs, and constructed the first STPK protein interaction (KPI) map that includes 492 binding proteins and 1,027 interactions. Bioinformatics analysis showed that the interacting proteins reflect diverse functions, including roles in two-component system, transcription, protein degradation, and cell wall integrity. Functional investigations confirmed that PknG regulates cell wall integrity through key components of peptidoglycan (PG) biosynthesis, e.g. MurC. The global STPK-KPIs network constructed here is expected to serve as a rich resource for understanding the key signaling pathways in Mtb, thus facilitating drug development and effective control of Mtb. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Differentiated roles for MreB-actin isologues and autolytic enzymes in Bacillus subtilis morphogenesis.

PubMed

Domínguez-Cuevas, Patricia; Porcelli, Ida; Daniel, Richard A; Errington, Jeff

2013-09-01

Cell morphogenesis in most bacteria is governed by spatiotemporal growth regulation of the peptidoglycan cell wall layer. Much is known about peptidoglycan synthesis but regulation of its turnover by hydrolytic enzymes is much less well understood. Bacillus subtilis has a multitude of such enzymes. Two of the best characterized are CwlO and LytE: cells lacking both enzymes have a lethal block in cell elongation. Here we show that activity of CwlO is regulated by an ABC transporter, FtsEX, which is required for cell elongation, unlike cell division as in Escherichia coli. Actin-like MreB proteins are thought to play a key role in orchestrating cell wall morphogenesis. B. subtilis has three MreB isologues with partially differentiated functions. We now show that the three MreB isologues have differential roles in regulation of the CwlO and LytE systems and that autolysins control different aspects of cell morphogenesis. The results add major autolytic activities to the growing list of functions controlled by MreB isologues in bacteria and provide new insights into the different specialized functions of essential cell wall autolysins. © 2013 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

Adipose tissue stem cells in regenerative medicine

PubMed Central

Miana, Vanesa Verónica; González, Elio A Prieto

2018-01-01

Adipose tissue-derived stem cells (ADSCs) are mesenchymal cells with the capacity for self-renewal and multipotential differentiation. This multipotentiality allows them to become adipocytes, chondrocytes, myocytes, osteoblasts and neurocytes among other cell lineages. Stem cells and, in particular, adipose tissue-derived cells, play a key role in reconstructive or tissue engineering medicine as they have already proven effective in developing new treatments. The purpose of this work is to review the applications of ADSCs in various areas of regenerative medicine, as well as some of the risks associated with treatment with ADSCs in neoplastic disease. PMID:29662535

Role of nuclear progesterone receptor isoforms in uterine pathophysiology

PubMed Central

Patel, Bansari; Elguero, Sonia; Thakore, Suruchi; Dahoud, Wissam; Bedaiwy, Mohamed; Mesiano, Sam

2015-01-01

BACKGROUND Progesterone is a key hormonal regulator of the female reproductive system. It plays a major role to prepare the uterus for implantation and in the establishment and maintenance of pregnancy. Actions of progesterone on the uterine tissues (endometrium, myometrium and cervix) are mediated by the combined effects of two progesterone receptor (PR) isoforms, designated PR-A and PR-B. Both receptors function primarily as ligand-activated transcription factors. Progesterone action on the uterine tissues is qualitatively and quantitatively determined by the relative levels and transcriptional activities of PR-A and PR-B. The transcriptional activity of the PR isoforms is affected by specific transcriptional coregulators and by PR post-translational modifications that affect gene promoter targeting. In this context, appropriate temporal and cell-specific expression and function of PR-A and PR-B are critical for normal uterine function. METHODS Relevant studies describing the role of PRs in uterine physiology and pathology (endometriosis, uterine leiomyoma, endometrial cancer, cervical cancer and recurrent pregnancy loss) were comprehensively searched using PubMed, Cochrane Library, Web of Science, and Google Scholar and critically reviewed. RESULTS Progesterone, acting through PR-A and PR-B, regulates the development and function of the endometrium and induces changes in cells essential for implantation and the establishment and maintenance of pregnancy. During pregnancy, progesterone via the PRs promotes myometrial relaxation and cervical closure. Withdrawal of PR-mediated progesterone signaling triggers menstruation and parturition. PR-mediated progesterone signaling is anti-mitogenic in endometrial epithelial cells, and as such, mitigates the tropic effects of estrogen on eutopic normal endometrium, and on ectopic implants in endometriosis. Similarly, ligand-activated PRs function as tumor suppressors in endometrial cancer cells through inhibition of key cellular signaling pathways required for growth. In contrast, progesterone via PR activation appears to increase leiomyoma growth. The exact role of PRs in cervical cancer is unclear. PRs regulate implantation and therefore aberrant PR function may be implicated in recurrent pregnancy loss (RPL). PRs likely regulate key immunogenic factors involved in RPL. However, the exact role of PRs in the pathophysiology of RPL and the use of progesterone for therapeutic benefit remains uncertain. CONCLUSIONS PRs are key mediators of progesterone action in uterine tissues and are essential for normal uterine function. Aberrant PR function (due to abnormal expression and/or function) is a major cause of uterine pathophysiology. Further investigation of the underlying mechanisms of PR isoform action in the uterus is required, as this knowledge will afford the opportunity to create progestin/PR-based therapeutics to treat various uterine pathologies. PMID:25406186

Deciphering the Role of B Cells in Multiple Sclerosis—Towards Specific Targeting of Pathogenic Function

PubMed Central

Lehmann-Horn, Klaus; Kinzel, Silke; Weber, Martin S.

2017-01-01

B cells, plasma cells and antibodies may play a key role in the pathogenesis of multiple sclerosis (MS). This notion is supported by various immunological changes observed in MS patients, such as activation and pro-inflammatory differentiation of peripheral blood B cells, the persistence of clonally expanded plasma cells producing immunoglobulins in the cerebrospinal fluid, as well as the composition of inflammatory central nervous system lesions frequently containing co-localizing antibody depositions and activated complement. In recent years, the perception of a respective pathophysiological B cell involvement was vividly promoted by the empirical success of anti-CD20-mediated B cell depletion in clinical trials; based on these findings, the first monoclonal anti-CD20 antibody—ocrelizumab—is currently in the process of being approved for treatment of MS. In this review, we summarize the current knowledge on the role of B cells, plasma cells and antibodies in MS and elucidate how approved and future treatments, first and foremost anti-CD20 antibodies, therapeutically modify these B cell components. We will furthermore describe regulatory functions of B cells in MS and discuss how the evolving knowledge of these therapeutically desirable B cell properties can be harnessed to improve future safety and efficacy of B cell-directed therapy in MS. PMID:28946620

Integrative Genomic Analysis of In Vivo Muscle Regeneration After Severe Trauma

DTIC Science & Technology

2015-11-30

along with pro-inflammatory cytokines activate downstream target genes such as c-Myc, reported to drive satellite cell proliferation21 and repress...between the US Department of Energy and the US Army Medical Research and Materiel Command. The views, opinions, and/or findings of this report are...pathway member Yap plays a key role in influencing fate decisions in muscle satellite cells. J. Cell Sci. 125, 6009-6019 (2012). 27. McKinsey , T.A

WASH overexpression enhances cancer stem cell properties and correlates with poor prognosis of esophageal carcinoma.

PubMed

Huang, Lan; Lian, Jingyao; Chen, Xinfeng; Qin, Guohui; Zheng, Yujia; Zhang, Yi

2017-12-01

There is increasing evidence that cytoskeleton remodeling is involved in cancer progression. Wiskott-Aldrich syndrome protein (WASP) family represents a key regulator of actin cytoskeleton remodeling. However, the underlying mechanism of the WASP family in cancer progression remains elusive. Here, we studied the role of WASP and SCAR Homolog (WASH), a recently identified WASP family member, in human esophageal squamous cell carcinoma (ESCC). Using three human ESCC cell lines, we found that WASH expression was significantly elevated in cancer stem-like cells enriched by sphere formation assay. WASH knockdown decreased the sphere-forming capacity of esophageal cancer cells whereas WASH over-expression exhibited the opposite effect. Mechanistically, we identified interleukin-8 (IL-8) as a key downstream target of WASH. IL-8 knockdown completely attenuated tumor sphere formation induced by WASH overexpression. WASH knockdown also delayed the growth of human ESCC xenografts in BALB/c nude mice. Importantly, high WASH levels were associated with poor clinical prognosis in a total of 145 human ESCC tissues. Collectively, our results suggest an essential role of the WASH/IL-8 pathway in human ESCC by maintaining the stemness of cancer cells. Hence, targeting this pathway might represent a promising strategy to control human esophageal carcinoma. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Expression of transmembrane 4 superfamily (TM4SF) proteins and their role in hepatic stellate cell motility and wound healing migration.

PubMed

Mazzocca, Antonio; Carloni, Vinicio; Sciammetta, Silvia; Cordella, Claudia; Pantaleo, Pietro; Caldini, Anna; Gentilini, Paolo; Pinzani, Massimo

2002-09-01

Migration of activated hepatic stellate cells (HSC) is a key event in the progression of liver fibrosis. Little is known about transmembrane proteins involved in HSC motility. Tetraspanins (TM4SF) have been implicated in cell development, differentiation, motility and tumor cell invasion. We evaluated the expression and function of four TM4SF, namely CD9, CD81, CD63 and CD151, and their involvement in HSC migration, adhesion, and proliferation. All TM4SF investigated were highly expressed at the human HSC surface with different patterns of intracellular distribution. Monoclonal antibodies directed against the four TM4SF inhibited HSC migration induced by extracellular matrix proteins in both wound healing and haptotaxis assays. This inhibition was independent of the ECM substrates employed (collagen type I or IV, laminin), and was comparable to that obtained by incubating the cells with an anti-beta1 blocking mAb. Importantly, cell adhesion was unaffected by the incubation with the same antibodies. Co-immunoprecipitation studies revealed different patterns of association between the four TM4SF studied and beta1 integrin. Finally, anti-TM4SF antibodies did not affect HSC growth. These findings provide the first characterization of tetraspanins expression and of their role in HSC migration, a key event in liver tissue wound healing and fibrogenesis.

GSK-3β: A Bifunctional Role in Cell Death Pathways.

PubMed

Jacobs, Keith M; Bhave, Sandeep R; Ferraro, Daniel J; Jaboin, Jerry J; Hallahan, Dennis E; Thotala, Dinesh

2012-01-01

Although glycogen synthase kinase-3 beta (GSK-3β) was originally named for its ability to phosphorylate glycogen synthase and regulate glucose metabolism, this multifunctional kinase is presently known to be a key regulator of a wide range of cellular functions. GSK-3β is involved in modulating a variety of functions including cell signaling, growth metabolism, and various transcription factors that determine the survival or death of the organism. Secondary to the role of GSK-3β in various diseases including Alzheimer's disease, inflammation, diabetes, and cancer, small molecule inhibitors of GSK-3β are gaining significant attention. This paper is primarily focused on addressing the bifunctional or conflicting roles of GSK-3β in both the promotion of cell survival and of apoptosis. GSK-3β has emerged as an important molecular target for drug development.

Fatty acid synthase regulates the chemosensitivity of breast cancer cells to cisplatin-induced apoptosis.

PubMed

Al-Bahlani, Shadia; Al-Lawati, Hanaa; Al-Adawi, Moza; Al-Abri, Nadia; Al-Dhahli, Buthaina; Al-Adawi, Kawther

2017-06-01

Fatty acid synthase (FASN) is a key enzyme in fat biosynthesis that is over-expressed in advanced breast cancer stages. Cisplatin (CDDP) is a platinum-based drug used in the treatment of certain types of this disease. Although it was shown that FASN inhibition induced apoptosis by enhancing the cytotoxicity of certain drugs in breast cancer, its role in regulating the chemosensitivity of different types of breast cancer cells to CDDP-induced apoptosis is not established yet. Therefore, two different breast cancer cell lines; triple negative breast cancer (TNBC; MDA-MB-231) and triple positive breast cancer (TPBC; BT-474) cells were used to examine such role. We show that TNBC cells had naturally less fat content than TPBC cells. Subsequently, the fat content increased in both cells when treated with Palmitate rather than Oleate, whereas both fatty acids produced apoptotic ultra-structural effects and attenuated FASN expression. However, Oleate increased FASN expression in TPBC cells. CDDP decreased FASN expression and increased apoptosis in TNBC cells. These effects were further enhanced by combining CDDP with fatty acids. We also illustrate that the inhibition of FASN by either siRNA or exogenous inhibitor decreased CDDP-induced apoptosis in TPBC cells suggesting its role as an apoptotic factor, while an opposite finding was observed in TNBC cells when siRNA and fatty acids were used, suggesting its role as a survival factor. To our knowledge, we are the first to demonstrate a dual role of FASN in CDDP-induced apoptosis in breast cancer cells and how it can modulate their chemosensitivity.

Novel Role of MDA-9/Syntenin in Regulating Urothelial Cell Proliferation by Modulating EGFR Signaling

PubMed Central

Dasgupta, Santanu; Menezes, Mitchell E.; Das, Swadesh K.; Emdad, Luni; Janjic, Aleksandar; Bhatia, Shilpa; Mukhopadhyay, Nitai D; Shao, Chunbo; Sarkar, Devanand; Fisher, Paul B.

2013-01-01

Purpose Urothelial cell carcinoma (UCC) rapidly progresses from superficial to muscle-invasive tumors. The key molecules involved in metastatic progression and its early detection require clarification. The present study defines a seminal role of the metastasis-associated gene MDA-9/Syntenin in UCC progression. Experimental Design Expression pattern of MDA-9/Syntenin was examined in 44 primary UCC and the impact of its overexpression and knock down was examined in multiple cells lines and key findings were validated in primary tumors. Results Significantly higher (p= 0.002–0.003) expression of MDA-9/Syntenin was observed in 64% (28/44) of primary tumors and an association was evident with stage (p=0.01), grade (p=0.03) and invasion status (p=0.02). MDA-9/Syntenin overexpression in non-tumorigenic HUC-1 cells increased proliferation (p=0.0012), invasion (p=0.0001) and EGFR, AKT, PI3K and c-Src expression. Alteration of Beta-catenin, E-Cadherin, Vimentin, Claudin-1, ZO-1 and TCF4 expression were also observed. MDA-9/Syntenin knock down in 3 UCC cell lines reversed phenotypic and molecular changes observed in the HUC-1 cells and reduced in vivo metastasis. Key molecular changes observed in the cell lines were confirmed in primary tumors. A physical interaction and co-localization of MDA-9/Syntenin and EGFR was evident in UCC cell lines and primary tumors. A logistic regression model analysis revealed a significant correlation between MDA-9/Syntenin:EGFR and MDA-9/Syntenin: AKT expressions with stage (p=0.04, EGFR), (p=0.01, AKT). A correlation between MDA-9/Syntenin: β-catenin co-expression with stage (p=0.03) and invasion (p=0.04) was also evident. Conclusions Our findings indicate that MDA-9/Syntenin might provide an attractive target for developing detection, monitoring and therapeutic strategies for managing UCC. PMID:23873690

Identification of small molecule Hes1 modulators as potential anticancer chemotherapeutics.

PubMed

Sail, Vibhavari; Hadden, M Kyle

2013-03-01

Hes1 is a key transcriptional regulator primarily controlled by the Notch signaling pathway, and recent studies have demonstrated both an oncogenic and tumor suppressor role for Hes1, depending on the cell type. Small molecules that activate and inhibit Hes1 activity hold promise as future anticancer chemotherapeutics. We have utilized a cell-based dual luciferase assay to identify modulators of Hes1 expression in a medium-throughput format. A modest screen was performed in HCT-116 colon cancer cell lines, and two small molecules were identified and characterized as Hes1 regulators. Compound 3 induced Hes1 expression and exhibited anticancer effects in pulmonary carcinoid tumor cells, a cell type in which the upregulated Notch/Hes1 signaling plays a tumor suppressive role. Treatment of HCT-116 cells with compound 12 resulted in Hes1 downregulation and antitumor effects. © 2012 John Wiley & Sons A/S.

The involvement of plasmacytoid cells in HIV infection and pathogenesis.

PubMed

Aiello, Alessandra; Giannessi, Flavia; Percario, Zulema A; Affabris, Elisabetta

2018-04-01

Plasmacytoid dendritic cells (pDCs) are a unique dendritic cell subset that are specialized in type I interferon (IFN) production. pDCs are key players in the antiviral immune response and serve as bridge between innate and adaptive immunity. Although pDCs do not represent the main reservoir of the Human Immunodeficiency Virus (HIV), they are a crucial subset in HIV infection as they influence viral transmission, target cell infection and antigen presentation. pDCs act as inflammatory and immunosuppressive cells, thus contributing to HIV disease progression. This review provides a state of art analysis of the interactions between HIV and pDCs and their potential roles in HIV transmission, chronic immune activation and immunosuppression. A thorough understanding of the roles of pDCs in HIV infection will help to improve therapeutic strategies to fight HIV infection, and will further increase our knowledge on this important immune cell subset. Copyright © 2018 Elsevier Ltd. All rights reserved.

Novel functions for the transcription factor E2F4 in development and disease

PubMed Central

Sage, Julien

2016-01-01

ABSTRACT The E2F family of transcription factors is a key determinant of cell proliferation in response to extra- and intra-cellular signals. Within this family, E2F4 is a transcriptional repressor whose activity is critical to engage and maintain cell cycle arrest in G0/G1 in conjunction with members of the retinoblastoma (RB) family. However, recent observations challenge this paradigm and indicate that E2F4 has a multitude of functions in cells besides this cell cycle regulatory role, including in embryonic and adult stem cells, during regenerative processes, and in cancer. Some of these new functions are independent of the RB family and involve direct activation of target genes. Here we review the canonical functions of E2F4 and discuss recent evidence expanding the role of this transcription factor, with a focus on cell fate decisions in tissue homeostasis and regeneration. PMID:27753528

Structural-Functional Organization of the Eukaryotic Cell Nucleus and Transcription Regulation: Introduction to This Special Issue of Biochemistry (Moscow).

PubMed

Razin, S V

2018-04-01

This issue of Biochemistry (Moscow) is devoted to the cell nucleus and mechanisms of transcription regulation. Over the years, biochemical processes in the cell nucleus have been studied in isolation, outside the context of their spatial organization. Now it is clear that segregation of functional processes within a compartmentalized cell nucleus is very important for the implementation of basic genetic processes. The functional compartmentalization of the cell nucleus is closely related to the spatial organization of the genome, which in turn plays a key role in the operation of epigenetic mechanisms. In this issue of Biochemistry (Moscow), we present a selection of review articles covering the functional architecture of the eukaryotic cell nucleus, the mechanisms of genome folding, the role of stochastic processes in establishing 3D architecture of the genome, and the impact of genome spatial organization on transcription regulation.

High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis.

PubMed

Wang, Qiannan; An, Bang; Shi, Haitao; Luo, Hongli; He, Chaozu

2017-05-05

N -acetyl-5-methoxytryptamine (Melatonin), as a crucial messenger in plants, functions in adjusting biological rhythms, stress tolerance, plant growth and development. Several studies have shown the retardation effect of exogenous melatonin treatment on plant growth and development. However, the in vivo role of melatonin in regulating plant leaf growth and the underlying mechanism are still unclear. In this study, we found that high concentration of melatonin suppressed leaf growth in Arabidopsis by reducing both cell size and cell number. Further kinetic analysis of the fifth leaves showed that melatonin remarkably inhibited cell division rate. Additionally, flow cytometic analysis indicated that melatonin negatively regulated endoreduplication during leaf development. Consistently, the expression analysis revealed that melatonin regulated the transcriptional levels of key genes of cell cycle and ribosome. Taken together, this study suggests that high concentration of melatonin negatively regulated the leaf growth and development in Arabidopsis , through modulation of endoreduplication and the transcripts of cell cycle and ribosomal key genes.

High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis

PubMed Central

Wang, Qiannan; An, Bang; Shi, Haitao; Luo, Hongli; He, Chaozu

2017-01-01

N-acetyl-5-methoxytryptamine (Melatonin), as a crucial messenger in plants, functions in adjusting biological rhythms, stress tolerance, plant growth and development. Several studies have shown the retardation effect of exogenous melatonin treatment on plant growth and development. However, the in vivo role of melatonin in regulating plant leaf growth and the underlying mechanism are still unclear. In this study, we found that high concentration of melatonin suppressed leaf growth in Arabidopsis by reducing both cell size and cell number. Further kinetic analysis of the fifth leaves showed that melatonin remarkably inhibited cell division rate. Additionally, flow cytometic analysis indicated that melatonin negatively regulated endoreduplication during leaf development. Consistently, the expression analysis revealed that melatonin regulated the transcriptional levels of key genes of cell cycle and ribosome. Taken together, this study suggests that high concentration of melatonin negatively regulated the leaf growth and development in Arabidopsis, through modulation of endoreduplication and the transcripts of cell cycle and ribosomal key genes. PMID:28475148

The role of myosin II in glioma invasion: A mathematical model

PubMed Central

Lee, Wanho; Lim, Sookkyung; Kim, Yangjin

2017-01-01

Gliomas are malignant tumors that are commonly observed in primary brain cancer. Glioma cells migrate through a dense network of normal cells in microenvironment and spread long distances within brain. In this paper we present a two-dimensional multiscale model in which a glioma cell is surrounded by normal cells and its migration is controlled by cell-mechanical components in the microenvironment via the regulation of myosin II in response to chemoattractants. Our simulation results show that the myosin II plays a key role in the deformation of the cell nucleus as the glioma cell passes through the narrow intercellular space smaller than its nuclear diameter. We also demonstrate that the coordination of biochemical and mechanical components within the cell enables a glioma cell to take the mode of amoeboid migration. This study sheds lights on the understanding of glioma infiltration through the narrow intercellular spaces and may provide a potential approach for the development of anti-invasion strategies via the injection of chemoattractants for localization. PMID:28166231

Perspectives on Regulatory T Cell Therapies

PubMed Central

Probst-Kepper, Michael; Kröger, Andrea; Garritsen, Henk S.P.; Buer, Jan

2009-01-01

Summary Adoptive transfer in animal models clearly indicate an essential role of CD4+ CD25+ FOXP3+ regulatory T (Treg) cells in prevention and treatment of autoimmune and graft-versus-host disease. Thus, Treg cell therapies and development of drugs that specifically enhance Treg cell function and development represent promising tools to establish dominant tolerance. So far, lack of specific markers to differentiate human Treg cells from activated CD4+ CD25+ effector T cells, which also express FOXP3 at different levels, hampered such an approach. Recent identification of the orphan receptor glycoprotein-A repetitions predominant (GARP or LRRC32) as Treg cell-specific key molecule that dominantly controls FOXP3 via a positive feedback loop opens up new perspectives for molecular and cellular therapies. This brief review focuses on the role of GARP as a safeguard of a complex regulatory network of human Treg cells and its implications for regulatory T cell therapies in autoimmunity and graft-versus-host disease. PMID:21076548

Perspectives on Regulatory T Cell Therapies.

PubMed

Probst-Kepper, Michael; Kröger, Andrea; Garritsen, Henk S P; Buer, Jan

2009-01-01

Adoptive transfer in animal models clearly indicate an essential role of CD4+ CD25+ FOXP3+ regulatory T (T(reg)) cells in prevention and treatment of autoimmune and graft-versus-host disease. Thus, T(reg) cell therapies and development of drugs that specifically enhance T(reg) cell function and development represent promising tools to establish dominant tolerance. So far, lack of specific markers to differentiate human T(reg) cells from activated CD4+ CD25+ effector T cells, which also express FOXP3 at different levels, hampered such an approach. Recent identification of the orphan receptor glycoprotein-A repetitions predominant (GARP or LRRC32) as T(reg) cell-specific key molecule that dominantly controls FOXP3 via a positive feedback loop opens up new perspectives for molecular and cellular therapies. This brief review focuses on the role of GARP as a safeguard of a complex regulatory network of human T(reg) cells and its implications for regulatory T cell therapies in autoimmunity and graft-versus-host disease.

Advanced glycation end products increase carbohydrate responsive element binding protein expression and promote cancer cell proliferation.

PubMed

Chen, Hanbei; Wu, Lifang; Li, Yakui; Meng, Jian; Lin, Ning; Yang, Dianqiang; Zhu, Yemin; Li, Xiaoyong; Li, Minle; Xu, Ye; Wu, Yuchen; Tong, Xuemei; Su, Qing

2014-09-01

Diabetic patients have increased levels of advanced glycation end products (AGEs) and the role of AGEs in regulating cancer cell proliferation is unclear. Here, we found that treating colorectal and liver cancer cells with AGEs promoted cell proliferation. AGEs stimulated both the expression and activation of a key transcription factor called carbohydrate responsive element binding protein (ChREBP) which had been shown to promote glycolytic and anabolic activity as well as proliferation of colorectal and liver cancer cells. Using siRNAs or the antagonistic antibody for the receptor for advanced glycation end-products (RAGE) blocked AGEs-induced ChREBP expression or cell proliferation in cancer cells. Suppressing ChREBP expression severely impaired AGEs-induced cancer cell proliferation. Taken together, these results demonstrate that AGEs-RAGE signaling enhances cancer cell proliferation in which AGEs-mediated ChREBP induction plays an important role. These findings may provide new explanation for increased cancer progression in diabetic patients. Copyright © 2014. Published by Elsevier Ireland Ltd.

SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells

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

Bonifati, Serena; Daly, Michele B.; St Gelais, Corine

SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G{sub 1}/G{sub 0} phase and reduces apoptosis. These alterationsmore » correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection.« less

Live-cell imaging of migrating cells expressing fluorescently-tagged proteins in a three-dimensional matrix.

PubMed

Shih, Wenting; Yamada, Soichiro

2011-12-22

Traditionally, cell migration has been studied on two-dimensional, stiff plastic surfaces. However, during important biological processes such as wound healing, tissue regeneration, and cancer metastasis, cells must navigate through complex, three-dimensional extracellular tissue. To better understand the mechanisms behind these biological processes, it is important to examine the roles of the proteins responsible for driving cell migration. Here, we outline a protocol to study the mechanisms of cell migration using the epithelial cell line (MDCK), and a three-dimensional, fibrous, self-polymerizing matrix as a model system. This optically clear extracellular matrix is easily amenable to live-cell imaging studies and better mimics the physiological, soft tissue environment. This report demonstrates a technique for directly visualizing protein localization and dynamics, and deformation of the surrounding three-dimensional matrix. Examination of protein localization and dynamics during cellular processes provides key insight into protein functions. Genetically encoded fluorescent tags provide a unique method for observing protein localization and dynamics. Using this technique, we can analyze the subcellular accumulation of key, force-generating cytoskeletal components in real-time as the cell maneuvers through the matrix. In addition, using multiple fluorescent tags with different wavelengths, we can examine the localization of multiple proteins simultaneously, thus allowing us to test, for example, whether different proteins have similar or divergent roles. Furthermore, the dynamics of fluorescently tagged proteins can be quantified using Fluorescent Recovery After Photobleaching (FRAP) analysis. This measurement assays the protein mobility and how stably bound the proteins are to the cytoskeletal network. By combining live-cell imaging with the treatment of protein function inhibitors, we can examine in real-time the changes in the distribution of proteins and morphology of migrating cells. Furthermore, we also combine live-cell imaging with the use of fluorescent tracer particles embedded within the matrix to visualize the matrix deformation during cell migration. Thus, we can visualize how a migrating cell distributes force-generating proteins, and where the traction forces are exerted to the surrounding matrix. Through these techniques, we can gain valuable insight into the roles of specific proteins and their contributions to the mechanisms of cell migration.

Growth and development of the root apical meristem.

PubMed

Perilli, Serena; Di Mambro, Riccardo; Sabatini, Sabrina

2012-02-01

A key question in plant developmental biology is how cell division and cell differentiation are balanced to modulate organ growth and shape organ size. In recent years, several advances have been made in understanding how this balance is achieved during root development. In the Arabidopsis root meristem, stem cells in the apical region of the meristem self-renew and produce daughter cells that differentiate in the distal meristem transition zone. Several factors have been implicated in controlling the different functional zones of the root meristem to modulate root growth; among these, plant hormones have been shown to play a main role. In this review, we summarize recent findings regarding the role of hormone signaling and transcriptional networks in regulating root development. Copyright © 2011 Elsevier Ltd. All rights reserved.

Glycogen metabolism has a key role in the cancer microenvironment and provides new targets for cancer therapy.

PubMed

Zois, Christos E; Harris, Adrian L

2016-02-01

Metabolic reprogramming is a hallmark of cancer cells and contributes to their adaption within the tumour microenvironment and resistance to anticancer therapies. Recently, glycogen metabolism has become a recognised feature of cancer cells since it is upregulated in many tumour types, suggesting that it is an important aspect of cancer cell pathophysiology. Here, we provide an overview of glycogen metabolism and its regulation, with a focus on its role in metabolic reprogramming of cancer cells under stress conditions such as hypoxia, glucose deprivation and anticancer treatment. The various methods to detect glycogen in tumours in vivo as well as pharmacological modulators of glycogen metabolism are also reviewed. Finally, we discuss the therapeutic value of targeting glycogen metabolism as a strategy for combinational approaches in cancer treatment.

Rho-associated kinase (ROCK) function is essential for cell cycle progression, senescence and tumorigenesis

PubMed Central

Kümper, Sandra; Mardakheh, Faraz K; McCarthy, Afshan; Yeo, Maggie; Stamp, Gordon W; Paul, Angela; Worboys, Jonathan; Sadok, Amine; Jørgensen, Claus; Guichard, Sabrina

2016-01-01

Rho-associated kinases 1 and 2 (ROCK1/2) are Rho-GTPase effectors that control key aspects of the actin cytoskeleton, but their role in proliferation and cancer initiation or progression is not known. Here, we provide evidence that ROCK1 and ROCK2 act redundantly to maintain actomyosin contractility and cell proliferation and that their loss leads to cell-cycle arrest and cellular senescence. This phenotype arises from down-regulation of the essential cell-cycle proteins CyclinA, CKS1 and CDK1. Accordingly, while the loss of either Rock1 or Rock2 had no negative impact on tumorigenesis in mouse models of non-small cell lung cancer and melanoma, loss of both blocked tumor formation, as no tumors arise in which both Rock1 and Rock2 have been genetically deleted. Our results reveal an indispensable role for ROCK, yet redundant role for isoforms 1 and 2, in cell cycle progression and tumorigenesis, possibly through the maintenance of cellular contractility. DOI: http://dx.doi.org/10.7554/eLife.12203.001 PMID:26765561

Di-(2-ethylhexyl) phthalate could disrupt the insulin signaling pathway in liver of SD rats and L02 cells via PPARγ

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

Zhang, Wang; Shen, Xin-Yue; Zhang, Wen-wen

Di-(2-ethylhexyl)-phthalate (DEHP), a ubiquitous industrial pollutant in our daily life, has been reported to cause adverse effects on glucose homeostasis and insulin sensitivity in epidemiological studies previously. Recently, it has been reported to be an endocrine disrupter and ligand to peroxisome proliferator activated receptor, which could influence the homeostasis of liver metabolic systems and contribute to the development of type-2 diabetes. However, the potential mechanisms are not known yet. This study was designed to solve these problems with male SD rats and normal human hepatocyte line, L02 cells, exposed to DEHP for toxicological experiments. Adult male SD rats were dividedmore » into four groups, normal group fed with regular diets and three DEHP-treated groups (dissolved in olive oil at doses of 0.05, 5 and 500 mg/kg body weight, respectively, once daily through gastric intubations for 15 weeks). L02 cells were divided into 6 groups, normal group with 5, 10, 25, 50, and 100 μmol/l DEHP groups. DEHP-exposed rats exhibited significant liver damage, glucose tolerance, and insulin tolerance along with reduced expression of insulin receptor and GLUT4 proteins in the liver tissues. The results of in vitro experiments could determine that the DEHP-induced activation of peroxisome proliferator activated receptor γ (PPARγ) played a key role in the production of oxidative stress and down-regulated expression of insulin receptor and GLUT4 proteins in L02 cells. This conclusion could be supported by the results of in vitro experiments, in which the cells were exposed to DEHP with GW9662 (PPARγ inhibitor). In general, these results highlight the key role of PPARγ in the process of insulin resistance induced by DEHP. - Highlights: • DEHP exacerbates insulin resistance both in liver tissues and cells. • Expression of insulin receptor and GLUT4 were altered with PPARγ. • DEHP can induce oxidative stress to disrupt the metabolic homeostasis. • The dose of exposed DEHP is closed to daily exposure by human. • Determine the key role of PPARγ to insulin resistance.« less

DBC1 promotes castration-resistant prostate cancer by positively regulating DNA binding and stability of AR-V7.

PubMed

Moon, Sue Jin; Jeong, Byong Chang; Kim, Hwa Jin; Lim, Joung Eun; Kwon, Ghee Young; Kim, Jeong Hoon

2018-03-01

Constitutively active AR-V7, one of the major androgen receptor (AR) splice variants lacking the ligand-binding domain, plays a key role in the development of castration-resistant prostate cancer (CRPC) and anti-androgen resistance. However, our understanding of the regulatory mechanisms of AR-V7-driven transcription is limited. Here we report DBC1 as a key regulator of AR-V7 transcriptional activity and stability in CRPC cells. DBC1 functions as a coactivator for AR-V7 and is required for the expression of AR-V7 target genes including CDH2, a mesenchymal marker linked to CRPC progression. DBC1 is required for recruitment of AR-V7 to its target enhancers and for long-range chromatin looping between the CDH2 enhancer and promoter. Mechanistically, DBC1 enhances DNA-binding activity of AR-V7 by direct interaction and inhibits CHIP E3 ligase-mediated ubiquitination and degradation of AR-V7 by competing with CHIP for AR-V7 binding, thereby stabilizing and activating AR-V7. Importantly, DBC1 depletion suppresses the tumorigenic and metastatic properties of CRPC cells. Our results firmly establish DBC1 as a critical AR-V7 coactivator that plays a key role in the regulation of DNA binding and stability of AR-V7 and has an important physiological role in CRPC progression.

Reduced Autophagy by a microRNA-mediated Signaling Cascade in Diabetes-induced Renal Glomerular Hypertrophy.

PubMed

Deshpande, Supriya; Abdollahi, Maryam; Wang, Mei; Lanting, Linda; Kato, Mitsuo; Natarajan, Rama

2018-05-03

Autophagy plays a key role in the pathogenesis of kidney diseases, however its role in diabetic nephropathy (DN), and particularly in kidney glomerular mesangial cells (MCs) is not very clear. Transforming Growth Factor- β1 (TGF-β), a key player in the pathogenesis of DN, regulates expression of various microRNAs (miRNAs), some of which are known to regulate the expression of autophagy genes. Here we demonstrate that miR-192, induced by TGF-β signaling, plays an important role in regulating autophagy in DN. The expression of key autophagy genes was decreased in kidneys of streptozotocin-injected type-1 and type-2 (db/db) diabetic mice and this was reversed by treatment with Locked Nucleic Acid (LNA) modified miR-192 inhibitors. Changes in autophagy gene expression were also attenuated in kidneys of diabetic miR-192-KO mice. In vitro studies using mouse glomerular mesangial cells (MMCs) also showed a decrease in autophagy gene expression with TGF-β treatment. miR-192 mimic oligonucleotides also decreased the expression of certain autophagy genes. These results demonstrate that TGF-β and miR-192 decrease autophagy in MMCs under diabetic conditions and this can be reversed by inhibition or deletion of miR-192, further supporting miR-192 as a useful therapeutic target for DN.

Mechanisms of Oral Tolerance.

PubMed

Tordesillas, Leticia; Berin, M Cecilia

2018-02-27

Oral tolerance is a state of systemic unresponsiveness that is the default response to food antigens in the gastrointestinal tract, although immune tolerance can also be induced by other routes, such as the skin or inhalation. Antigen can be acquired directly by intestinal phagocytes, or pass through enterocytes or goblet cell-associated passages prior to capture by dendritic cells (DCs) in the lamina propria. Mucin from goblet cells acts on DCs to render them more tolerogenic. A subset of regulatory DCs expressing CD103 is responsible for delivery of antigen to the draining lymph node and induction of Tregs. These DCs also imprint gastrointestinal homing capacity, allowing the recently primed Tregs to home back to the lamina propria where they interact with macrophages that produce IL-10 and expand. Tregs induced by dietary antigen include Foxp3 + Tregs and Foxp3 - Tregs. In addition to Tregs, T cell anergy can also contribute to oral tolerance. The microbiota plays a key role in the development of oral tolerance, through regulation of macrophages and innate lymphoid cells that contribute to the regulatory phenotype of gastrointestinal dendritic cells. Absence of microbiota is associated with a susceptibility to food allergy, while presence of Clostridia strains can suppress development of food allergy through enhancement of Tregs and intestinal barrier function. It is not clear if feeding of antigens can also induce true immune tolerance after a memory immune response has been generated, but mechanistic studies of oral immunotherapy trials demonstrate shared pathways in oral tolerance and oral immunotherapy, with a role for Tregs and anergy. An important role for IgA and IgG antibodies in development of immune tolerance is also supported by studies of oral tolerance in humans. The elucidation of key pathways in oral tolerance could identify new strategies to increase efficacy of immunotherapy treatments for food allergy.

CDC-42 Orients Cell Migration during Epithelial Intercalation in the Caenorhabditis elegans Epidermis.

PubMed

Walck-Shannon, Elise; Lucas, Bethany; Chin-Sang, Ian; Reiner, David; Kumfer, Kraig; Cochran, Hunter; Bothfeld, William; Hardin, Jeff

2016-11-01

Cell intercalation is a highly directed cell rearrangement that is essential for animal morphogenesis. As such, intercalation requires orchestration of cell polarity across the plane of the tissue. CDC-42 is a Rho family GTPase with key functions in cell polarity, yet its role during epithelial intercalation has not been established because its roles early in embryogenesis have historically made it difficult to study. To circumvent these early requirements, in this paper we use tissue-specific and conditional loss-of-function approaches to identify a role for CDC-42 during intercalation of the Caenorhabditis elegans dorsal embryonic epidermis. CDC-42 activity is enriched in the medial tips of intercalating cells, which extend as cells migrate past one another. Moreover, CDC-42 is involved in both the efficient formation and orientation of cell tips during cell rearrangement. Using conditional loss-of-function we also show that the PAR complex functions in tip formation and orientation. Additionally, we find that the sole C. elegans Eph receptor, VAB-1, functions during this process in an Ephrin-independent manner. Using epistasis analysis, we find that vab-1 lies in the same genetic pathway as cdc-42 and is responsible for polarizing CDC-42 activity to the medial tip. Together, these data establish a previously uncharacterized role for polarized CDC-42, in conjunction with PAR-6, PAR-3 and an Eph receptor, during epithelial intercalation.

CDC-42 Orients Cell Migration during Epithelial Intercalation in the Caenorhabditis elegans Epidermis

PubMed Central

Lucas, Bethany; Chin-Sang, Ian; Reiner, David; Kumfer, Kraig

2016-01-01

Cell intercalation is a highly directed cell rearrangement that is essential for animal morphogenesis. As such, intercalation requires orchestration of cell polarity across the plane of the tissue. CDC-42 is a Rho family GTPase with key functions in cell polarity, yet its role during epithelial intercalation has not been established because its roles early in embryogenesis have historically made it difficult to study. To circumvent these early requirements, in this paper we use tissue-specific and conditional loss-of-function approaches to identify a role for CDC-42 during intercalation of the Caenorhabditis elegans dorsal embryonic epidermis. CDC-42 activity is enriched in the medial tips of intercalating cells, which extend as cells migrate past one another. Moreover, CDC-42 is involved in both the efficient formation and orientation of cell tips during cell rearrangement. Using conditional loss-of-function we also show that the PAR complex functions in tip formation and orientation. Additionally, we find that the sole C. elegans Eph receptor, VAB-1, functions during this process in an Ephrin-independent manner. Using epistasis analysis, we find that vab-1 lies in the same genetic pathway as cdc-42 and is responsible for polarizing CDC-42 activity to the medial tip. Together, these data establish a previously uncharacterized role for polarized CDC-42, in conjunction with PAR-6, PAR-3 and an Eph receptor, during epithelial intercalation. PMID:27861585

MicroRNAs in Control of Stem Cells in Normal and Malignant Hematopoiesis

PubMed Central

Roden, Christine; Lu, Jun

2016-01-01

Studies on hematopoietic stem cells (HSCs) and leukemia stem cells (LSCs) have helped to establish the paradigms of normal and cancer stem cell concepts. For both HSCs and LSCs, specific gene expression programs endowed by their epigenome functionally distinguish them from their differentiated progenies. MicroRNAs (miRNAs), as a class of small non-coding RNAs, act to control post-transcriptional gene expression. Research in the past decade has yielded exciting findings elucidating the roles of miRNAs in control of multiple facets of HSC and LSC biology. Here we review recent progresses on the functions of miRNAs in HSC emergence during development, HSC switch from a fetal/neonatal program to an adult program, HSC self-renewal and quiescence, HSC aging, HSC niche, and malignant stem cells. While multiple different miRNAs regulate a diverse array of targets, two common themes emerge in HSC and LSC biology: miRNA mediated regulation of epigenetic machinery and cell signaling pathways. In addition, we propose that miRNAs themselves behave like epigenetic regulators, as they possess key biochemical and biological properties that can provide both stability and alterability to the epigenetic program. Overall, the studies of miRNAs in stem cells in the hematologic contexts not only provide key understandings to post-transcriptional gene regulation mechanisms in HSCs and LSCs, but also will lend key insights for other stem cell fields. PMID:27547713

Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival

PubMed Central

Datta, Antara; Silverman, Lee; Phipps, Andrew J; Hiraragi, Hajime; Ratner, Lee; Lairmore, Michael D

2007-01-01

Background Human T-lymphotropic virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation. Results Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C), had enhanced checkpoint kinase 1 (Chk1) serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1), diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes. Conclusion Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T-cell survival. PMID:17634129

The Role of PD-1 Ligand in Immune Evasion by Breast Cancer

DTIC Science & Technology

2005-05-01

with anti-CD11c-PE and either anti-PD-L1-FITC or anti-PD-L2-FITC and an- alyzed by flow cytometry . 1260 BLOCKADE OF PD-L ON DC ENHANCES T CELL... surface staining. . In order to accomplish these epitope blocking studies, we made 300.19 and CHO cells transfected with PD-L1 or PD-L2. For anti...Key Research Accomplishments 1. PD-L1 but not PD-L2 is highly expressed on the cell surface of breast cancer cells but not on normal breast

IL-15/IL-15 receptor biology: a guided tour through an expanding universe.

PubMed

Budagian, Vadim; Bulanova, Elena; Paus, Ralf; Bulfone-Paus, Silvia

2006-08-01

The cytokine interleukin-15 (IL-15) has a key role in promoting survival, proliferation and activation of natural killer (NK) and CD8+ T cells. Despite its functional similarities to IL-2, IL-15 affects a wider range of target cell populations and utilizes different mechanisms of signaling. Here, we review recent advances in the IL-15-mediated signaling, and in the functional properties on cells besides T lymphocytes and NK cells. These are discussed in the context of their potential clinical and therapeutic relevance.

Changes in the Adult Vertebrate Auditory Sensory Epithelium After Trauma

PubMed Central

Oesterle, Elizabeth C.

2012-01-01

Auditory hair cells transduce sound vibrations into membrane potential changes, ultimately leading to changes in neuronal firing and sound perception. This review provides an overview of the characteristics and repair capabilities of traumatized auditory sensory epithelium in the adult vertebrate ear. Injured mammalian auditory epithelium repairs itself by forming permanent scars but is unable to regenerate replacement hair cells. In contrast, injured non-mammalian vertebrate ear generates replacement hair cells to restore hearing functions. Non-sensory support cells within the auditory epithelium play key roles in the repair processes. PMID:23178236

Adiponectin and Its Receptors in the Ovary: Further Evidence for a Link between Obesity and Hyperandrogenism in Polycystic Ovary Syndrome

PubMed Central

Comim, Fabio V.; Hardy, Kate; Franks, Stephen

2013-01-01

Polycystic ovary syndrome (PCOS), characterized by ovarian androgen excess, is the commonest endocrine disorder in women. Obesity increases androgen synthesis, a phenomenon attributed to the accompanying hyperinsulinemia. Our hypothesis was that adipokines, fat cell-derived hormones, play a direct role in modulating ovarian androgen secretion. Therefore, the aims of this study were to explore the effects of adipokines (in particular, adiponectin) on ovarian steroidogenesis and compare the expression of adiponectin receptors in ovaries from women with and without PCO. Sections of archived human ovaries (nine from women with normal ovaries and 16 with PCOS, classified histologically, with reference to menstrual history and ultrasound) were analysed by quantitative morphometry and the proportion of positive-labelling cells compared. In addition, studies of androgen production in relation to adipokine function in primary bovine theca cell culture were also performed. A significantly lower proportion of theca cells expressed adiponectin receptors 1 and 2 (AdipoR1, AdipoR2) in polycystic ovaries than in normal ovaries. In cultured theca cells, adiponectin suppressed androstenedione production and gene expression of LH receptor and key enzymes in the androgen synthesis pathway. Moreover, knockdown of genes for AdipoR1 and AdipoR2 was associated with increased androstenedione secretion by bovine theca cells. These results provide evidence for a direct link between fat cell metabolism and ovarian steroidogenesis, suggesting that disruption of adiponectin and/or its receptors plays a key role in pathogenesis of hyperandrogenism in PCOS. PMID:24260388

Quantitative cell polarity imaging defines leader-to-follower transitions during collective migration and the key role of microtubule-dependent adherens junction formation.

PubMed

Revenu, Céline; Streichan, Sebastian; Donà, Erika; Lecaudey, Virginie; Hufnagel, Lars; Gilmour, Darren

2014-03-01

The directed migration of cell collectives drives the formation of complex organ systems. A characteristic feature of many migrating collectives is a 'tissue-scale' polarity, whereby 'leader' cells at the edge of the tissue guide trailing 'followers' that become assembled into polarised epithelial tissues en route. Here, we combine quantitative imaging and perturbation approaches to investigate epithelial cell state transitions during collective migration and organogenesis, using the zebrafish lateral line primordium as an in vivo model. A readout of three-dimensional cell polarity, based on centrosomal-nucleus axes, allows the transition from migrating leaders to assembled followers to be quantitatively resolved for the first time in vivo. Using live reporters and a novel fluorescent protein timer approach, we investigate changes in cell-cell adhesion underlying this transition by monitoring cadherin receptor localisation and stability. This reveals that while cadherin 2 is expressed across the entire tissue, functional apical junctions are first assembled in the transition zone and become progressively more stable across the leader-follower axis of the tissue. Perturbation experiments demonstrate that the formation of these apical adherens junctions requires dynamic microtubules. However, once stabilised, adherens junction maintenance is microtubule independent. Combined, these data identify a mechanism for regulating leader-to-follower transitions within migrating collectives, based on the relocation and stabilisation of cadherins, and reveal a key role for dynamic microtubules in this process.

Curcumin may serve an anticancer role in human osteosarcoma cell line U-2 OS by targeting ITPR1.

PubMed

Luo, Zhanpeng; Li, Dawei; Luo, Xiaobo; Li, Litao; Gu, Suxi; Yu, Long; Ma, Yuanzheng

2018-04-01

The present study aimed to determine the mechanisms of action of curcumin in osteosarcoma. Human osteosarcoma U-2 OS cells was purchased from the Cell Bank of the Chinese Academy of Sciences. RNA sequencing analysis was performed for 2 curcumin-treated samples and 2 control samples using Illumina deep sequencing technology. The differentially expressed genes were identified using Cufflink software. Enrichment and protein-protein interaction network analyses were performed separately using cluster Profiler package and Cytoscape software to identify key genes. Then, the mRNA levels of key genes were detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR) in U-2 OS cells. Finally, cell apoptosis, proliferation, migration and invasion arrays were performed. In total, 201 DEGs were identified in the curcumin-treated group. EEF1A1 (degree=88), ATF7IP, HIF1A, SMAD7, CLTC, MCM10, ITPR1, ADAM15, WWP2 and ATP5C1, which were enriched in 'biological process', exhibited higher degrees than other genes in the PPI network. RT-qPCR demonstrated that treatment with curcumin was able to significantly increase the levels of CLTC and ITPR1 mRNA in curcumin-treated cells compared with control. In addition, targeting ITPR1 with curcumin significantly promoted apoptosis and suppressed proliferation, migration and invasion. Targeting ITPR1 via curcumin may serve an anticancer role by mediating apoptosis, proliferation, migration and invasion in U-2 OS cells.

The Role of ARX in Human Pancreatic Endocrine Specification

PubMed Central

Gage, Blair K.; Asadi, Ali; Baker, Robert K.; Webber, Travis D.; Wang, Rennian; Itoh, Masayuki; Hayashi, Masaharu; Miyata, Rie; Akashi, Takumi; Kieffer, Timothy J.

2015-01-01

The in vitro differentiation of human embryonic stem cells (hESCs) offers a model system to explore human development. Humans with mutations in the transcription factor Aristaless Related Homeobox (ARX) often suffer from the syndrome X-linked lissencephaly with ambiguous genitalia (XLAG), affecting many cell types including those of the pancreas. Indeed, XLAG pancreatic islets lack glucagon and pancreatic polypeptide-positive cells but retain somatostatin, insulin, and ghrelin-positive cells. To further examine the role of ARX in human pancreatic endocrine development, we utilized genomic editing in hESCs to generate deletions in ARX. ARX knockout hESCs retained pancreatic differentiation capacity and ARX knockout endocrine cells were biased toward somatostatin-positive cells (94% of endocrine cells) with reduced pancreatic polypeptide (rarely detected), glucagon (90% reduced) and insulin-positive (65% reduced) lineages. ARX knockout somatostatin-positive cells shared expression patterns with human fetal and adult δ-cells. Differentiated ARX knockout cells upregulated PAX4, NKX2.2, ISL1, HHEX, PCSK1, PCSK2 expression while downregulating PAX6 and IRX2. Re-expression of ARX in ARX knockout pancreatic progenitors reduced HHEX and increased PAX6 and insulin expression following differentiation. Taken together these data suggest that ARX plays a key role in pancreatic endocrine fate specification of pancreatic polypeptide, somatostatin, glucagon and insulin positive cells from hESCs. PMID:26633894

The Role of ARX in Human Pancreatic Endocrine Specification.

PubMed

Gage, Blair K; Asadi, Ali; Baker, Robert K; Webber, Travis D; Wang, Rennian; Itoh, Masayuki; Hayashi, Masaharu; Miyata, Rie; Akashi, Takumi; Kieffer, Timothy J

2015-01-01

The in vitro differentiation of human embryonic stem cells (hESCs) offers a model system to explore human development. Humans with mutations in the transcription factor Aristaless Related Homeobox (ARX) often suffer from the syndrome X-linked lissencephaly with ambiguous genitalia (XLAG), affecting many cell types including those of the pancreas. Indeed, XLAG pancreatic islets lack glucagon and pancreatic polypeptide-positive cells but retain somatostatin, insulin, and ghrelin-positive cells. To further examine the role of ARX in human pancreatic endocrine development, we utilized genomic editing in hESCs to generate deletions in ARX. ARX knockout hESCs retained pancreatic differentiation capacity and ARX knockout endocrine cells were biased toward somatostatin-positive cells (94% of endocrine cells) with reduced pancreatic polypeptide (rarely detected), glucagon (90% reduced) and insulin-positive (65% reduced) lineages. ARX knockout somatostatin-positive cells shared expression patterns with human fetal and adult δ-cells. Differentiated ARX knockout cells upregulated PAX4, NKX2.2, ISL1, HHEX, PCSK1, PCSK2 expression while downregulating PAX6 and IRX2. Re-expression of ARX in ARX knockout pancreatic progenitors reduced HHEX and increased PAX6 and insulin expression following differentiation. Taken together these data suggest that ARX plays a key role in pancreatic endocrine fate specification of pancreatic polypeptide, somatostatin, glucagon and insulin positive cells from hESCs.

Immunology and Immunotherapy of Head and Neck Cancer.

PubMed

Ferris, Robert L

2015-10-10

The immune system plays a key role in the development, establishment, and progression of head and neck squamous cell carcinoma (HNSCC). A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of HNSCC provides the basis for improved therapies and outcomes for patients. HNSCC cells evade the host immune system through manipulation of their own immunogenicity, production of immunosuppressive mediators, and promotion of immunomodulatory cell types. Through the tumor's influence on the microenvironment, the immune system can be exploited to promote metastasis, angiogenesis, and growth. This article provides a brief overview of key components of the immune infiltrating cells in the tumor microenvironment, reviewing immunological principles related to head and neck cancer, including the concept of cancer immunosurveillance and immune escape. Current immunotherapeutic strategies and emerging results from ongoing clinical trials are presented. © 2015 by American Society of Clinical Oncology.

Astrocyte elevated gene-1 regulates hepatocellular carcinoma development and progression

PubMed Central

Yoo, Byoung Kwon; Emdad, Luni; Su, Zao-zhong; Villanueva, Augusto; Chiang, Derek Y.; Mukhopadhyay, Nitai D.; Mills, Alan Scott; Waxman, Samuel; Fisher, Robert A.; Llovet, Josep M.; Fisher, Paul B.; Sarkar, Devanand

2009-01-01

Hepatocellular carcinoma (HCC) is a highly aggressive vascular cancer characterized by diverse etiology, activation of multiple signal transduction pathways, and various gene mutations. Here, we have determined a specific role for astrocyte elevated gene-1 (AEG1) in HCC pathogenesis. Expression of AEG1 was extremely low in human hepatocytes, but its levels were significantly increased in human HCC. Stable overexpression of AEG1 converted nontumorigenic human HCC cells into highly aggressive vascular tumors, and inhibition of AEG1 abrogated tumorigenesis by aggressive HCC cells in a xenograft model of nude mice. In human HCC, AEG1 overexpression was associated with elevated copy numbers. Microarray analysis revealed that AEG1 modulated the expression of genes associated with invasion, metastasis, chemoresistance, angiogenesis, and senescence. AEG1 also was found to activate Wnt/β-catenin signaling via ERK42/44 activation and upregulated lymphoid-enhancing factor 1/T cell factor 1 (LEF1/TCF1), the ultimate executor of the Wnt pathway, important for HCC progression. Inhibition studies further demonstrated that activation of Wnt signaling played a key role in mediating AEG1 function. AEG1 also activated the NF-κB pathway, which may play a role in the chronic inflammatory changes preceding HCC development. These data indicate that AEG1 plays a central role in regulating diverse aspects of HCC pathogenesis. Targeted inhibition of AEG1 might lead to the shutdown of key elemental characteristics of HCC and could lead to an effective therapeutic strategy for HCC. PMID:19221438

Sex-specific control of CNS autoimmunity by p38 MAPK signaling in myeloid cells

PubMed Central

Krementsov, Dimitry N.; Noubade, Rajkumar; Dragon, Julie A.; Otsu, Kinya; Rincon, Mercedes; Teuscher, Cory

2013-01-01

Objective Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), characterized by a global increasing incidence driven by relapsing-remitting disease in females. p38 MAP kinase (MAPK) has been described as a key regulator of inflammatory responses in autoimmunity, but its role in the sexual dimorphism in MS or MS models remains unexplored. Methods Toward this end, we used experimental autoimmune encephalomyelitis (EAE), the principal animal model of MS, combined with pharmacologic and genetic inhibition of p38 MAPK activity and transcriptomic analyses. Results Pharmacologic inhibition of p38 MAPK selectively ameliorated EAE in female mice. Conditional deletion studies demonstrated that p38α signaling in macrophages/myeloid cells, but not T cells or dendritic cells, recapitulated this sexual dimorphism. Analysis of CNS inflammatory infiltrates showed that female, but not male mice lacking p38α in myeloid cells exhibited reduced immune cell activation compared with controls, while peripheral T cell priming was unaffected in both sexes. Transcriptomic analyses of myeloid cells revealed differences in p38α-controlled transcripts comprising female- and male-specific gene modules, with greater p38α dependence of pro-inflammatory gene expression in females. Interpretation Our findings demonstrate a key role for p38α in myeloid cells in CNS autoimmunity and uncover important molecular mechanisms underlying sex differences in disease pathogenesis. Taken together, our results suggest that the p38 MAPK signaling pathway represents a novel target for much needed disease modifying therapies for MS. PMID:24027119

Comparative glycan profiling of Ceratopteris richardii ‘C-Fern’ gametophytes and sporophytes links cell-wall composition to functional specialization

PubMed Central

Eeckhout, Sharon; Leroux, Olivier; Willats, William G. T.; Popper, Zoë A.; Viane, Ronald L. L.

2014-01-01

Background and Aims Innovations in vegetative and reproductive characters were key factors in the evolutionary history of land plants and most of these transformations, including dramatic changes in life cycle structure and strategy, necessarily involved cell-wall modifications. To provide more insight into the role of cell walls in effecting changes in plant structure and function, and in particular their role in the generation of vascularization, an antibody-based approach was implemented to compare the presence and distribution of cell-wall glycan epitopes between (free-living) gametophytes and sporophytes of Ceratopteris richardii ‘C-Fern’, a widely used model system for ferns. Methods Microarrays of sequential diamino-cyclohexane-tetraacetic acid (CDTA) and NaOH extractions of gametophytes, spores and different organs of ‘C-Fern’ sporophytes were probed with glycan-directed monoclonal antibodies. The same probes were employed to investigate the tissue- and cell-specific distribution of glycan epitopes. Key Results While monoclonal antibodies against pectic homogalacturonan, mannan and xyloglucan widely labelled gametophytic and sporophytic tissues, xylans were only detected in secondary cell walls of the sporophyte. The LM5 pectic galactan epitope was restricted to sporophytic phloem tissue. Rhizoids and root hairs showed similarities in arabinogalactan protein (AGP) and xyloglucan epitope distribution patterns. Conclusions The differences and similarities in glycan cell-wall composition between ‘C-Fern’ gametophytes and sporophytes indicate that the molecular design of cell walls reflects functional specialization rather than genetic origin. Glycan epitopes that were not detected in gametophytes were associated with cell walls of specialized tissues in the sporophyte. PMID:24699895

Targeting vacuolar H+-ATPases as a new strategy against cancer.

PubMed

Fais, Stefano; De Milito, Angelo; You, Haiyan; Qin, Wenxin

2007-11-15

Growing evidence suggests a key role of tumor acidic microenvironment in cancer development, progression, and metastasis. As a consequence, the need for compounds that specifically target the mechanism(s) responsible for the low pH of tumors is increasing. Among the key regulators of the tumor acidic microenvironment, vacuolar H(+)-ATPases (V-ATPases) play an important role. These proteins cover a number of functions in a variety of normal as well as tumor cells, in which they pump ions across the membranes. We discuss here some recent results showing that a molecular inhibition of V-ATPases by small interfering RNA in vivo as well as a pharmacologic inhibition through proton pump inhibitors led to tumor cytotoxicity and marked inhibition of human tumor growth in xenograft models. These results propose V-ATPases as a key target for new strategies in cancer treatment.

STATs shape the active enhancer landscape of T cell populations.

PubMed

Vahedi, Golnaz; Takahashi, Hayato; Nakayamada, Shingo; Sun, Hong-Wei; Sartorelli, Vittorio; Kanno, Yuka; O'Shea, John J

2012-11-21

Signaling pathways are intimately involved in cellular differentiation, allowing cells to respond to their environment by regulating gene expression. Although enhancers are recognized as key elements that regulate selective gene expression, the interplay between signaling pathways and actively used enhancer elements is not clear. Here, we use CD4(+) T cells as a model of differentiation, mapping the activity of cell-type-specific enhancer elements in T helper 1 (Th1) and Th2 cells. Our data establish that STAT proteins have a major impact on the activation of lineage-specific enhancers and the suppression of enhancers associated with alternative cell fates. Transcriptome analysis further supports a functional role for enhancers regulated by STATs. Importantly, expression of lineage-defining master regulators in STAT-deficient cells fails to fully recover the chromatin signature of STAT-dependent enhancers. Thus, these findings point to a critical role of STATs as environmental sensors in dynamically molding the specialized enhancer architecture of differentiating cells. Copyright © 2012 Elsevier Inc. All rights reserved.

STATs Shape the Active Enhancer Landscape of T Cell Populations

PubMed Central

Vahedi, Golnaz; Takahashi, Hayato; Nakayamada, Shingo; Sun, Hong-wei; Sartorelli, Vittorio; Kanno, Yuka; O’Shea, John J.

2012-01-01

SUMMARY Signaling pathways are intimately involved in cellular differentiation, allowing cells to respond to their environment by regulating gene expression. While enhancers are recognized as key elements that regulate selective gene expression, the interplay between signaling pathways and actively used enhancer elements is not clear. Here, we use CD4+ T cells as a model of differentiation, mapping the acquisition of cell-type-specific enhancer elements in T-helper 1 (Th1) and Th2 cells. Our data establish that STAT proteins have a major impact on the acquisition of lineage-specific enhancers and the suppression of enhancers associated with alternative cell fates. Transcriptome analysis further supports a functional role for enhancers regulated by STATs. Importantly, expression of lineage-defining master regulators in STAT-deficient cells fails to fully recover the chromatin signature of STAT-dependent enhancers. Thus, these findings point to a critical role of STATs as environmental sensors in dynamically molding the specialized enhancer architecture of differentiating cells. PMID:23178119

Functional defect in regulatory T cells in myasthenia gravis

PubMed Central

Thiruppathi, Muthusamy; Rowin, Julie; Jiang, Qin Li; Sheng, Jian Rong; Prabhakar, Bellur S.; Meriggioli, Matthew N.

2012-01-01

Forkhead box P3 (FOXP3)+ is a transcription factor necessary for the function of regulatory T cells (Treg cells). Treg cells maintain immune homeostasis and self-tolerance, and play an important role in the prevention of autoimmune disease. Here, we discuss the role of Treg cells in the pathogenesis of myasthenia gravis (MG) and review evidence indicating that a significant defect in Treg cell in vitro suppressive function exists in MG patients, without an alteration in circulating frequency. This functional defect is associated with a reduced expression of key functional molecules such as FOXP3 on isolated Treg cells and appears to be more pronounced in immunosuppression-naive MG patients. In vitro administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced the suppressive function of Treg cells and up-regulated FOXP3 expression. These findings indicate a clinically relevant Treg cell–intrinsic defect in immune regulation in MG that may reveal a novel therapeutic target. PMID:23252899

Leptin enhances the invasive ability of glioma stem-like cells depending on leptin receptor expression.

PubMed

Han, Guosheng; Zhao, Wenyuan; Wang, Laixing; Yue, Zhijian; Zhao, Rui; Li, Yanan; Zhou, Xiaoping; Hu, Xiaowu; Liu, Jianmin

2014-01-16

Glioma stem-like cells have been demonstrated to have highly invasive activity, which is the major cause of glioma recurrence after therapy. Leptin plays a role in glioma invasion, however, whether and how leptin contributes to the biological properties of glioma stem-like cells, such as invasion, remains to be explored. In the current study, we aimed to explore the role of leptin during glioma stem-like cells invasion as well as the signaling pathway. We found that glioma stem-like cells exhibited high invasive potential, especially in the presence of leptin, Ob-R coexpressed with CD133 in glioma stem-like cells was showed to be responsible for leptin mediated invasion of glioma stem-like cells. Our results indicated that leptin served as a key intermediary linking the accumulation of excess adipokine to the invasion of glioma stem-like cells, which may be a novel therapeutic target for suppressing tumor invasion and recurrence. © 2013 Published by Elsevier B.V.

THE GERMLINE STEM CELL NICHE UNIT IN MAMMALIAN TESTES

PubMed Central

Oatley, Jon M.; Brinster, Ralph L.

2014-01-01

This review addresses current understanding of the germline stem cell niche unit in mammalian testes. Spermatogenesis is a classic model of tissue-specific stem cell function relying on self-renewal and differentiation of spermatogonial stem cells (SSCs). These fate decisions are influenced by a niche microenvironment composed of a growth factor milieu that is provided by several testis somatic support cell populations. Investigations over the last two decades have identified key determinants of the SSC niche including cytokines that regulate SSC functions and support cells providing these factors, adhesion molecules that influence SSC homing, and developmental heterogeneity of the niche during postnatal aging. Emerging evidence suggests that Sertoli cells are a key support cell population influencing the formation and function of niches by secreting soluble factors and possibly orchestrating contributions of other support cells. Investigations with mice have shown that niche influence on SSC proliferation differs during early postnatal development and adulthood. Moreover, there is mounting evidence of an age-related decline in niche function, which is likely influenced by systemic factors. Defining the attributes of stem cell niches is key to developing methods to utilize these cells for regenerative medicine. The SSC population and associated niche comprise a valuable model system for study that provides fundamental knowledge about the biology of tissue-specific stem cells and their capacity to sustain homeostasis of regenerating tissue lineages. While the stem cell is essential for maintenance of all self-renewing tissues and has received considerable attention, the role of niche cells is at least as important and may prove to be more receptive to modification in regenerative medicine. PMID:22535892

Identification of Fungal T Cell Epitopes by Mass Spectrometry-Based Proteomics.

PubMed

Roschitzki, Bernd; LeibundGut-Landmann, Salomé

2017-01-01

CD4 + T cells play a key role in host defense against many fungal infections. T cells are also implicated in vaccine immunity to fungi. To date, only a small number of fungal antigens have been identified. Knowing the antigenic determinants of fungi-specific T cells greatly facilitates the detection, enumeration and characterizes the antifungal T cells and it constitutes an important step toward the design and development of vaccination strategies. This chapter describes a method of MHC-II ligand elution and mass spectrometric analysis to identify naturally processed and presented fungal peptide epitopes.

Why proteomics is not the new genomics and the future of mass spectrometry in cell biology.

PubMed

Sidoli, Simone; Kulej, Katarzyna; Garcia, Benjamin A

2017-01-02

Mass spectrometry (MS) is an essential part of the cell biologist's proteomics toolkit, allowing analyses at molecular and system-wide scales. However, proteomics still lag behind genomics in popularity and ease of use. We discuss key differences between MS-based -omics and other booming -omics technologies and highlight what we view as the future of MS and its role in our increasingly deep understanding of cell biology. © 2017 Sidoli et al.

Tight junctions in cancer metastasis.

PubMed

Martin, Tracey A; Mason, Malcolm D; Jiang, Wen G

2011-01-01

Tight Junctions (TJ) are well known to function as a control for the paracellular diffusion of ions and certain molecules, it has however, become evident that the TJ has a vital role in maintaining cell to cell integrity. Loss of cohesion of the TJ structure can lead to invasion and ultimately to the metastasis of cancer cells. This review will discuss how modulation of expression of TJ molecules results in key changes in TJ barrier function leading to the progression of cancer and progression of metastasis.

Comparison of two strategies for detection of reactive oxygen species

NASA Astrophysics Data System (ADS)

Gao, Weidong; Zhou, Yuanshu; Gu, Yueqing

2014-09-01

Photodynamic therapy (PDT) is a clinically approved treatment that was applied to oncology , dermatology, and ophthalmology. Reactive oxygen species (ROS) play a important role in the efficacy of PDT. Online monitoring of reactive oxygen species is the key to understand effect of PDT treatment. We used Fluorescence probes DPBF and luminescent probe luminal to measure the ROS in cells. And we revaluate the relationship between the amount of light and cell survival. There is strongly correlated between the amount of light and cell kill.

Macrophages: Their Emerging Roles in Bone

PubMed Central

Sinder, Benjamin P; Pettit, Allison R; McCauley, Laurie K

2016-01-01

Macrophages are present in nearly all tissues and are critical for development, homeostasis, and regeneration. Resident tissue macrophages of bone, termed osteal macrophages, are recently classified myeloid cells that are distinct from osteoclasts. Osteal macrophages are located immediately adjacent to osteoblasts, regulate bone formation, and play diverse roles in skeletal homeostasis. Genetic or pharmacological modulation of macrophages in vivo results in significant bone phenotypes, and these phenotypes depend on which macrophage subsets are altered. Macrophages are also key mediators of osseous wound healing and fracture repair, with distinct roles at various stages of the repair process. A central function of macrophages is their phagocytic ability. Each day, billions of cells die in the body and efferocytosis (phagocytosis of apoptotic cells) is a critical process in both clearing dead cells and recruitment of replacement progenitor cells to maintain homeostasis. Recent data suggest a role for efferocytosis in bone biology and these new mechanisms are outlined. Finally, although macrophages have an established role in primary tumors, emerging evidence suggests that macrophages in bone support cancers which preferentially metastasize to the skeleton. Collectively, this developing area of osteoimmunology raises new questions and promises to provide novel insights into pathophysiologic conditions as well as therapeutic and regenerative approaches vital for skeletal health. PMID:26531055

Posttransplant Lymphoproliferative Disorders

PubMed Central

Ibrahim, Hazem A. H.; Naresh, Kikkeri N.

2012-01-01

Posttransplant lymphoproliferative disorders (PTLDs) are a group of diseases that range from benign polyclonal to malignant monoclonal lymphoid proliferations. They arise secondary to treatment with immunosuppressive drugs given to prevent transplant rejection. Three main pathologic subsets/stages of evolution are recognised: early, polymorphic, and monomorphic lesions. The pathogenesis of PTLDs seems to be multifactorial. Among possible infective aetiologies, the role of EBV has been studied in depth, and the virus is thought to play a central role in driving the proliferation of EBV-infected B cells that leads to subsequent development of the lymphoproliferative disorder. It is apparent, however, that EBV is not solely responsible for the “neoplastic” state. Accumulated genetic alterations of oncogenes and tumour suppressor genes (deletions, mutations, rearrangements, and amplifications) and epigenetic changes (aberrant hypermethylation) that involve tumour suppressor genes are integral to the pathogenesis. Antigenic stimulation also plays an evident role in the pathogenesis of PTLDs. Plasmacytoid dendritic cells (PDCs) that are critical to fight viral infections have been thought to play a pathogenetically relevant role in PTLDs. Furthermore, regulatory T cells (Treg cells), which are modulators of immune reactions once incited, seem to have an important role in PTLDs where antigenic stimulation is key for the pathogenesis. PMID:22570658

The pathophysiological role of PEDF in bone diseases.

PubMed

Broadhead, M L; Akiyama, T; Choong, P F M; Dass, C R

2010-04-01

First discovered in 1991 as a factor secreted by retinal pigment epithelial cells, the potency of pigment epithelium derived factor (PEDF) as an anti-angiogenic has led to examination of its role in active bone growth, repair and remodelling. In the musculoskeletal system, PEDF expression occurs particularly at sites of active bone formation. Expression has been noted in osteoblasts and to a lesser degree osteoclasts, the major classes of bone cells. In fact, PEDF is capable of inducing differentiation of precursor cells into mature osteoblasts. Expression and localisation are closely linked with that of vascular endothelial growth factor (VEGF). Studies at the epiphyseal plate have revealed that PEDF expression plays a key role in endochondral ossification, and beyond this may account for the epiphyseal plate's innate ability to resist neoplastic cell invasion. Collagen-1, the major protein in bone, is avidly bound by PEDF, implicating an important role played by this protein on PEDF function, possibly through MMP-2 and -9 activity. Surprisingly, the role of PEDF has not been evaluated more widely in bone disorders, so the challenge ahead lies in a more diverse evaluation of PEDF in various osteologic pathologies including osteoarthritis and fracture healing.

Cell Extrusion: A Stress-Responsive Force for Good or Evil in Epithelial Homeostasis.

PubMed

Ohsawa, Shizue; Vaughen, John; Igaki, Tatsushi

2018-02-05

Epithelial tissues robustly respond to internal and external stressors via dynamic cellular rearrangements. Cell extrusion acts as a key regulator of epithelial homeostasis by removing apoptotic cells, orchestrating morphogenesis, and mediating competitive cellular battles during tumorigenesis. Here, we delineate the diverse functions of cell extrusion during development and disease. We emphasize the expanding role for apoptotic cell extrusion in exerting morphogenetic forces, as well as the strong intersection of cell extrusion with cell competition, a homeostatic mechanism that eliminates aberrant or unfit cells. While cell competition and extrusion can exert potent, tumor-suppressive effects, dysregulation of either critical homeostatic program can fuel cancer progression. Copyright © 2018 Elsevier Inc. All rights reserved.

Inactive Gingipains from P. gingivalis Selectively Skews T Cells toward a Th17 Phenotype in an IL-6 Dependent Manner.

PubMed

Glowczyk, Izabela; Wong, Alicia; Potempa, Barbara; Babyak, Olena; Lech, Maciej; Lamont, Richard J; Potempa, Jan; Koziel, Joanna

2017-01-01

Gingipain cysteine proteases are considered key virulence factors of Porphyromonas gingivalis . They significantly influence antibacterial and homeostatic functions of macrophages, neutrophils, the complement system, and cytokine networks. Recent data indicate the role of P. gingivalis in T cell differentiation; however, the involvement of gingipains in this process remains elusive. Therefore, the aim of this study was to investigate the contribution of danger signals triggered by the gingipains on the generation of Th17 cells, which play a key role in protection against bacterial diseases but may cause chronic inflammation and bone resorption. To this end we compared the effects of the wild-type strain of P. gingivalis (W83) with its isogenic mutant devoid of gingipain activity (ΔKΔRAB), and bacterial cells pretreated with a highly-specific inhibitor of gingipains activity (KYTs). Antigen presenting cells (APCs), both professional (dendritic cells), and non-professional (gingival keratinocytes), exposed to viable bacteria expressed high amounts of cytokines (IL-6, IL-21, IL-23). These cytokines are reported to either stimulate or balance the Th17-dependent immune response. Surprisingly, cells infected with P. gingivalis devoid of gingipain activity showed increased levels of all tested cytokines compared to bacteria with fully active enzymes. The effect was dependent on both the reduction of cytokine proteolysis and the lack of cross-talk with other bacterial virulence factors, including LPS and fimbriae that induce de novo synthesis of cytokines. The profile of lymphocyte T differentiation from naive T cells showed enhanced generation of Th17 in response to bacteria with inactive gingipains. Moreover, we found that gingipain-dependent induction of Th17 cells was highly specific, since other T cell-subsets remained unchanged. Finally, inhibition of IL-6 signaling in dendritic cells led to a significant depletion of the Th17 population. Cumulatively, this study revealed a previously undisclosed role of gingipain activity in the process of Th17 differentiation reliant on blocking signaling through IL-6. Since inactivation of gingipains accelerates the skewing of T cells toward Th17 cells, which are detrimental in periodontitis, IL-6 signaling may serve as an attractive target for treatment of the disease.

Cell Cycle Control in the Early Embryonic Development of Aquatic Animal Species

PubMed Central

Siefert, Joseph C.; Clowdus, Emily A.; Sansam, Christopher L.

2016-01-01

The cell cycle is integrated with many aspects of embryonic development. Not only is proper control over the pace of cell proliferation important, but also the timing of cell cycle progression is coordinated with transcription, cell migration, and cell differentiation. Due to the ease with which the embryos of aquatic organisms can be observed and manipulated, they have been a popular choice for embryologists throughout history. In the cell cycle field, aquatic organisms have been extremely important because they have played a major role in the discovery and analysis of key regulators of the cell cycle. In particular, the frog Xenopus laevis has been instrumental for understanding how the basic embryonic cell cycle is regulated. More recently, the zebrafish has been used to understand how the cell cycle is remodeled during vertebrate development and how it is regulated during morphogenesis. This review describes how some of the unique strengths of aquatic species have been leveraged for cell cycle research and suggests how species such as Xenopus and zebrafish will continue to reveal the roles of the cell cycle in human biology and disease. PMID:26475527

Critical role of histone demethylase Jmjd3 in the regulation of CD4+ T cell differentiation

PubMed Central

Ding, Xilai; Chepelev, Iouri; Zhou, Xikun; Zhao, Wei; Wei, Gang; Cui, Jun; Zhao, Keji; Wang, Helen Y.; Wang, Rong-Fu

2014-01-01

Epigenetic factors have been implicated in the regulation of CD4+ T cell differentiation. Jmjd3 plays a role in many biological processes, but its in vivo function in T cell differentiation remains unknown. Here, we report that Jmjd3 ablation promotes CD4+ T cell differentiation into Th2 and Th17 cells in the small intestine and colon, and inhibits T cell differentiation into Th1 cells under different cytokine-polarizing conditions and in a Th1-dependent colitis model. Jmjd3 deficiency also restrains the plasticity of the conversion of Th2, Th17 or Treg cells to Th1 cells. The skewing of T cell differentiation is concomitant with changes in the expression of key transcription factors and cytokines. H3K27me3 and H3K4me3 levels in Jmjd3-deficient cells are correlated with altered gene expression through interactions with specific transcription factors. Our results identify Jmjd3 as an epigenetic factor in T cell differentiation via changes in histone methylation and target gene expression. PMID:25531312

Induced stem cell neoplasia in a cnidarian by ectopic expression of a POU domain transcription factor.

PubMed

Millane, R Cathriona; Kanska, Justyna; Duffy, David J; Seoighe, Cathal; Cunningham, Stephen; Plickert, Günter; Frank, Uri

2011-06-01

The evolutionary origin of stem cell pluripotency is an unresolved question. In mammals, pluripotency is limited to early embryos and is induced and maintained by a small number of key transcription factors, of which the POU domain protein Oct4 is considered central. Clonal invertebrates, by contrast, possess pluripotent stem cells throughout their life, but the molecular mechanisms that control their pluripotency are poorly defined. To address this problem, we analyzed the expression pattern and function of Polynem (Pln), a POU domain gene from the marine cnidarian Hydractinia echinata. We show that Pln is expressed in the embryo and adult stem cells of the animal and that ectopic expression in epithelial cells induces stem cell neoplasms and loss of epithelial tissue. Neoplasm cells downregulated the transgene but expressed the endogenous Pln gene and also Nanos, Vasa, Piwi and Myc, which are all known cnidarian stem cell markers. Retinoic acid treatment caused downregulation of Pln and the differentiation of neoplasm cells to neurosensory and epithelial cells. Pln downregulation by RNAi led to differentiation. Collectively, our results suggest an ancient role of POU proteins as key regulators of animal stem cells.

The adaptor protein SLP-76 regulates HIV-1 release and cell to cell transmission in T-cells

PubMed Central

Nagaraja, Tirumuru; Anand, Appakkudal R.; Zhao, Helong; Ganju, Ramesh K.

2014-01-01

HIV-1 infection in T-cells is regulated by T-cell receptor (TCR) activation. However, the cellular proteins of the TCR pathway that regulate HIV-1 infection are poorly characterized. Here, we elucidated the role of SLP-76, a key adaptor protein of the TCR signaling complex, in HIV-1 infection. We observed a significant reduction of HIV-1 virus production in SLP-76-deficient Jurkat T-cells compared to wild-type and SLP-76-reconstituted Jurkat T-cells. We further confirmed the role of SLP-76 in HIV-1 infection by siRNA-mediated knockdown in MT4 cells and PBMCs. Structural-functional analysis revealed that the amino-terminal domain of SLP-76 was important for regulating HIV-1 infection. Further mechanistic studies revealed that lack of SLP-76 impaired virus release, but did not affect viral entry, integration and transcription. We also showed that SLP-76 plays a critical role in cell-to-cell transmission of HIV-1. Signaling studies revealed that SLP-76 associated with viral Nef protein and multiple signaling molecules during HIV-1 infection. Furthermore, SLP-76 facilitated the association of Nef and F-actin, suggesting that SLP-76 mediates the formation of a signaling complex that may regulate viral release via cytoskeletal changes. Taken together, our studies demonstrate a novel role for the adaptor molecule, SLP-76 in regulating HIV-1 infection in T-cells with potential to develop innovative strategies against HIV-1. PMID:22323535

Insights into the role of components of the tumor microenvironment in oral carcinoma call for new therapeutic approaches

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

Salo, Tuula, E-mail: Tuula.salo@oulu.fi; Oulu University Central Hospital, Oulu; Institute of Dentistry, University of Helsinki, Helsinki

The research on oral cancer has focused mainly on the cancer cells, their genetic changes and consequent phenotypic modifications. However, it is increasingly clear that the tumor microenvironment (TME) has been shown to be in a dynamic state of inter-relations with the cancer cells. The TME contains a variety of components including the non-cancerous cells (i.e., immune cells, resident fibroblasts and angiogenic vascular cells) and the ECM milieu [including fibers (mainly collagen and fibronectin) and soluble factors (i.e., enzymes, growth factors, cytokines and chemokines)]. Thus, it is currently assumed that TME is considered a part of the cancerous tissue andmore » the functionality of its key components constitutes the setting on which the hallmarks of the cancer cells can evolve. Therefore, in terms of controlling a malignancy, one should control the growth, invasion and spread of the cancer cells through modifications in the TME components. This mini review focuses on the TME as a diagnostic approach and reports the recent insights into the role of different TME key components [such as carcinoma-associated fibroblasts (CAFs) and inflammation (CAI) cells, angiogenesis, stromal matrix molecules and proteases] in the molecular biology of oral carcinoma. Furthermore, the impact of TME components on clinical outcomes and the concomitant need for development of new therapeutic approaches will be discussed. - Highlights: • Tumor depth and budding, hypoxia and TME cells associate with worse prognosis. • Pro-tumoral CAFs and CAI cells aid proliferation, invasion and spread hypoxia. • Some ECM-bound factors exert pro-angiogenic or pro-tumor activities. • Tumor spread is greatly dependent on ECM proteolysis, mediated by TME cells. • Direct targeting of TME components for treatment is still experimental.« less

Attenuation of dexamethasone-induced cell death in multiple myeloma is mediated by miR-125b expression

PubMed Central

Murray, Megan Y.; Rushworth, Stuart A.; Zaitseva, Lyubov; Bowles, Kristian M.; MacEwan, David J.

2013-01-01

Dexamethasone is a key front-line chemotherapeutic for B-cell malignant multiple myeloma (MM). Dexamethasone modulates MM cell survival signaling but fails to induce marked cytotoxicity when used as a monotherapy. We demonstrate here the mechanism behind this insufficient responsiveness of MM cells toward dexamethasone, revealing in MM a dramatic anti-apoptotic role for microRNA (miRNA)-125b in the insensitivity toward dexamethasone-induced apoptosis. MM cells responding to dexamethasone exhibited enhanced expression of oncogenic miR-125b. Dexamethasone also induced expression of miR-34a, which acts to suppress SIRT1 deacetylase, and thus allows maintained acetylation and inactivation of p53. p53 mRNA is also suppressed by miR-125b targeting. Reporter assays showed that both these dexamethasone-induced miRNAs act downstream of their target genes to prevent p53 tumor suppressor actions and, ultimately, resist cytotoxic responses in MM. Use of antisense miR-125b transcripts enhanced expression of pro-apoptotic p53, repressed expression of anti-apoptotic SIRT1 and, importantly, significantly enhanced dexamethasone-induced cell death responses in MM. Pharmacological manipulations showed that the key regulation enabling complete dexamethasone sensitivity in MM cells lies with miR-125b. In summary, dexamethasone-induced miR-125b induces cell death resistance mechanisms in MM cells via the p53/miR-34a/SIRT1 signaling network and provides these cells with an enhanced level of resistance to cytotoxic chemotherapeutics. Clearly, such anti-apoptotic mechanisms will need to be overcome to more effectively treat nascent, refractory and relapsed MM patients. These mechanisms provide insight into the role of miRNA regulation of apoptosis and their promotion of MM cell proliferative mechanisms. PMID:23759586

Muscarinic receptor agonists stimulate human colon cancer cell migration and invasion.

PubMed

Belo, Angelica; Cheng, Kunrong; Chahdi, Ahmed; Shant, Jasleen; Xie, Guofeng; Khurana, Sandeep; Raufman, Jean-Pierre

2011-05-01

Muscarinic receptors (CHRM) are overexpressed in colon cancer. To explore a role for muscarinic receptor signaling in colon cancer metastasis, we used human H508 and HT29 colon cancer cells that coexpress epidermal growth factor (ERBB) and CHRM3 receptors. In a wound closure model, following 8-h incubation of H508 cells with 100 μM ACh we observed a threefold increase in cell migration indistinguishable from the actions of epidermal growth factor (EGF). Atropine blocked the actions of ACh but not of EGF. In SNU-C4 colon cancer cells that express ERBB but not CHRM, EGF caused a threefold increase in migration; ACh had no effect. ACh-induced cell migration was attenuated by chemical inhibitors of ERBB1 activation, by anti-ERBB1 antibody, and by inhibitors of ERK and phosphatidylinositol 3-kinase (PI3K) signaling. Consistent with matrix metalloproteinase-7 (MMP7)-mediated release of an ERBB1 ligand, heparin binding epidermal growth factor-like growth factor (HBEGF), ACh-induced migration was inhibited by an MMP inhibitor and by anti-MMP7 and -HBEGF antibodies. ACh-induced cell migration was blocked by inhibiting RhoA and ROCK, key proteins that interact with the actin cytoskeleton. ACh-induced RhoA activation was attenuated by agents that inhibit ERBB1, ERK, and PI3K activation. Collectively, these findings indicate that ACh-induced cell migration is mediated by MMP7-mediated release of HBEGF, an ERBB ligand that activates ERBB1 and downstream ERK and PI3K signaling. In a cell invasion model, ACh-induced HT29 cell invasion was blocked by atropine. In concert with previous observations, these findings indicate that muscarinic receptor signaling plays a key role in colon cancer cell proliferation, survival, migration, and invasion.

Muscarinic receptor agonists stimulate human colon cancer cell migration and invasion

PubMed Central

Belo, Angelica; Cheng, Kunrong; Chahdi, Ahmed; Shant, Jasleen; Xie, Guofeng; Khurana, Sandeep

2011-01-01

Muscarinic receptors (CHRM) are overexpressed in colon cancer. To explore a role for muscarinic receptor signaling in colon cancer metastasis, we used human H508 and HT29 colon cancer cells that coexpress epidermal growth factor (ERBB) and CHRM3 receptors. In a wound closure model, following 8-h incubation of H508 cells with 100 μM ACh we observed a threefold increase in cell migration indistinguishable from the actions of epidermal growth factor (EGF). Atropine blocked the actions of ACh but not of EGF. In SNU-C4 colon cancer cells that express ERBB but not CHRM, EGF caused a threefold increase in migration; ACh had no effect. ACh-induced cell migration was attenuated by chemical inhibitors of ERBB1 activation, by anti-ERBB1 antibody, and by inhibitors of ERK and phosphatidylinositol 3-kinase (PI3K) signaling. Consistent with matrix metalloproteinase-7 (MMP7)-mediated release of an ERBB1 ligand, heparin binding epidermal growth factor-like growth factor (HBEGF), ACh-induced migration was inhibited by an MMP inhibitor and by anti-MMP7 and -HBEGF antibodies. ACh-induced cell migration was blocked by inhibiting RhoA and ROCK, key proteins that interact with the actin cytoskeleton. ACh-induced RhoA activation was attenuated by agents that inhibit ERBB1, ERK, and PI3K activation. Collectively, these findings indicate that ACh-induced cell migration is mediated by MMP7-mediated release of HBEGF, an ERBB ligand that activates ERBB1 and downstream ERK and PI3K signaling. In a cell invasion model, ACh-induced HT29 cell invasion was blocked by atropine. In concert with previous observations, these findings indicate that muscarinic receptor signaling plays a key role in colon cancer cell proliferation, survival, migration, and invasion. PMID:21273532

Critical role of tissue mast cells in controlling long-term glucose sensor function in vivo.

PubMed

Klueh, Ulrike; Kaur, Manjot; Qiao, Yi; Kreutzer, Donald L

2010-06-01

Little is known about the specific cells, mediators and mechanisms involved in the loss of glucose sensor function (GSF) in vivo. Since mast cells (MC) are known to be key effector cells in inflammation and wound healing, we hypothesized that MC and their products are major contributors to the skin inflammation and wound healing that controls GSF at sites of sensor implantation. To test this hypothesis we utilized a murine model of continuous glucose monitoring (CGM) in vivo in both normal C57BL/6 mice (mast cell sufficient), as well as mast cell deficient B6.Cg-Kit(W-sh)/HNihrJaeBsmJ (Sash) mice over a 28 day CGM period. As expected, both strains of mice displayed excellent CGM for the first 7 days post sensor implantation (PSI). CGM in the mast cell sufficient C57BL/6 mice was erratic over the remaining 21 days PSI. CGM in the mast cell deficient Sash mice displayed excellent sensor function for the entire 28 day of CGM. Histopathologic evaluation of implantation sites demonstrated that tissue reactions in Sash mice were dramatically less compared to the reactions in normal C57BL/6 mice. Additionally, mast cells were also seen to be consistently associated with the margins of sensor tissue reactions in normal C57BL/6 mice. Finally, direct injection of bone marrow derived mast cells at sites of sensor implantation induced an acute and dramatic loss of sensor function in both C57BL/6 and Sash mice. These results demonstrate the key role of mast cells in controlling glucose sensor function in vivo. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

PEPCK Coordinates the Regulation of Central Carbon Metabolism to Promote Cancer Cell Growth.

PubMed

Montal, Emily D; Dewi, Ruby; Bhalla, Kavita; Ou, Lihui; Hwang, Bor Jang; Ropell, Ashley E; Gordon, Chris; Liu, Wan-Ju; DeBerardinis, Ralph J; Sudderth, Jessica; Twaddel, William; Boros, Laszlo G; Shroyer, Kenneth R; Duraisamy, Sekhar; Drapkin, Ronny; Powers, R Scott; Rohde, Jason M; Boxer, Matthew B; Wong, Kwok-Kin; Girnun, Geoffrey D

2015-11-19

Phosphoenolpyruvate carboxykinase (PEPCK) is well known for its role in gluconeogenesis. However, PEPCK is also a key regulator of TCA cycle flux. The TCA cycle integrates glucose, amino acid, and lipid metabolism depending on cellular needs. In addition, biosynthetic pathways crucial to tumor growth require the TCA cycle for the processing of glucose and glutamine derived carbons. We show here an unexpected role for PEPCK in promoting cancer cell proliferation in vitro and in vivo by increasing glucose and glutamine utilization toward anabolic metabolism. Unexpectedly, PEPCK also increased the synthesis of ribose from non-carbohydrate sources, such as glutamine, a phenomenon not previously described. Finally, we show that the effects of PEPCK on glucose metabolism and cell proliferation are in part mediated via activation of mTORC1. Taken together, these data demonstrate a role for PEPCK that links metabolic flux and anabolic pathways to cancer cell proliferation. Copyright © 2015 Elsevier Inc. All rights reserved.

Differentiation and Glucocorticoid Regulated Apopto-Phagocytic Gene Expression Patterns in Human Macrophages. Role of Mertk in Enhanced Phagocytosis

PubMed Central

Zahuczky, Gábor; Kristóf, Endre; Majai, Gyöngyike; Fésüs, László

2011-01-01

The daily clearance of physiologically dying cells is performed safely mainly by cells in the mononuclear phagocyte system. They can recognize and engulf dying cells utilizing several cooperative mechanisms. In our study we show that the expression of a broad range of apopto-phagocytic genes is strongly up-regulated during differentiation of human monocytes to macrophages with different donor variability. The glucocorticoid dexamethasone has a profound effect on this process by selectively up-regulating six genes and down-regulating several others. The key role of the up-regulated mer tyrosine kinase (Mertk) in dexamethasone induced enhancement of phagocytosis could be demonstrated in human monocyte derived macrophages by gene silencing as well as blocking antibodies, and also in a monocyte-macrophage like cell line. However, the additional role of other glucocorticoid induced elements must be also considered since the presence of autologous serum during phagocytosis could almost completely compensate for the blocked function of Mertk. PMID:21731712

Long Noncoding RNAs: New Players in the Osteogenic Differentiation of Bone Marrow- and Adipose-Derived Mesenchymal Stem Cells.

PubMed

Yang, Qiaolin; Jia, Lingfei; Li, Xiaobei; Guo, Runzhi; Huang, Yiping; Zheng, Yunfei; Li, Weiran

2018-06-01

Mesenchymal stem cells (MSCs) are an important population of multipotent stem cells that differentiate into multiple lineages and display great potential in bone regeneration and repair. Although the role of protein-coding genes in the osteogenic differentiation of MSCs has been extensively studied, the functions of noncoding RNAs in the osteogenic differentiation of MSCs are unclear. The recent application of next-generation sequencing to MSC transcriptomes has revealed that long noncoding RNAs (lncRNAs) are associated with the osteogenic differentiation of MSCs. LncRNAs are a class of non-coding transcripts of more than 200 nucleotides in length. Noncoding RNAs are thought to play a key role in osteoblast differentiation through various regulatory mechanisms including chromatin modification, transcription factor binding, competent endogenous mechanism, and other post-transcriptional mechanisms. Here, we review the roles of lncRNAs in the osteogenic differentiation of bone marrow- and adipose-derived stem cells and provide a theoretical foundation for future research.

Defining a Role for Acid Sphingomyelinase in the p38/Interleukin-6 Pathway*

PubMed Central

Perry, David M.; Newcomb, Benjamin; Adada, Mohamad; Wu, Bill X.; Roddy, Patrick; Kitatani, Kazuyuki; Siskind, Leah; Obeid, Lina M.; Hannun, Yusuf A.

2014-01-01

Acid sphingomyelinase (ASM) is one of the key enzymes involved in regulating the metabolism of the bioactive sphingolipid ceramide in the sphingolipid salvage pathway, yet defining signaling pathways by which ASM exerts its effects has proven difficult. Previous literature has implicated sphingolipids in the regulation of cytokines such as interleukin-6 (IL-6), but the specific sphingolipid pathways and mechanisms involved in inflammatory signaling need to be further elucidated. In this work, we sought to define the role of ASM in IL-6 production because our previous work showed that a parallel pathway of ceramide metabolism, acid β-glucosidase 1, negatively regulates IL-6. First, silencing ASM with siRNA abrogated IL-6 production in response to the tumor promoter, 4β-phorbol 12-myristate 13-acetate (PMA), in MCF-7 cells, in distinction to acid β-glucosidase 1 and acid ceramidase, suggesting specialization of the pathways. Moreover, treating cells with siRNA to ASM or with the indirect pharmacologic inhibitor desipramine resulted in significant inhibition of TNFα- and PMA-induced IL-6 production in MDA-MB-231 and HeLa cells. Knockdown of ASM was found to significantly inhibit PMA-dependent IL-6 induction at the mRNA level, probably ruling out mechanisms of translation or secretion of IL-6. Further, ASM knockdown or desipramine blunted p38 MAPK activation in response to TNFα, revealing a key role for ASM in activating p38, a signaling pathway known to regulate IL-6 induction. Last, knockdown of ASM dramatically blunted invasion of HeLa and MDA-MB-231 cells through Matrigel. Taken together, these results demonstrate that ASM plays a critical role in p38 signaling and IL-6 synthesis with implications for tumor pathobiology. PMID:24951586

Integrative analysis of DNA methylation and gene expression data identifies EPAS1 as a key regulator of COPD.

PubMed

Yoo, Seungyeul; Takikawa, Sachiko; Geraghty, Patrick; Argmann, Carmen; Campbell, Joshua; Lin, Luan; Huang, Tao; Tu, Zhidong; Foronjy, Robert F; Feronjy, Robert; Spira, Avrum; Schadt, Eric E; Powell, Charles A; Zhu, Jun

2015-01-01

Chronic Obstructive Pulmonary Disease (COPD) is a complex disease. Genetic, epigenetic, and environmental factors are known to contribute to COPD risk and disease progression. Therefore we developed a systematic approach to identify key regulators of COPD that integrates genome-wide DNA methylation, gene expression, and phenotype data in lung tissue from COPD and control samples. Our integrative analysis identified 126 key regulators of COPD. We identified EPAS1 as the only key regulator whose downstream genes significantly overlapped with multiple genes sets associated with COPD disease severity. EPAS1 is distinct in comparison with other key regulators in terms of methylation profile and downstream target genes. Genes predicted to be regulated by EPAS1 were enriched for biological processes including signaling, cell communications, and system development. We confirmed that EPAS1 protein levels are lower in human COPD lung tissue compared to non-disease controls and that Epas1 gene expression is reduced in mice chronically exposed to cigarette smoke. As EPAS1 downstream genes were significantly enriched for hypoxia responsive genes in endothelial cells, we tested EPAS1 function in human endothelial cells. EPAS1 knockdown by siRNA in endothelial cells impacted genes that significantly overlapped with EPAS1 downstream genes in lung tissue including hypoxia responsive genes, and genes associated with emphysema severity. Our first integrative analysis of genome-wide DNA methylation and gene expression profiles illustrates that not only does DNA methylation play a 'causal' role in the molecular pathophysiology of COPD, but it can be leveraged to directly identify novel key mediators of this pathophysiology.

Roles for Hedgehog signaling in adult organ homeostasis and repair

PubMed Central

Petrova, Ralitsa; Joyner, Alexandra L.

2014-01-01

The hedgehog (HH) pathway is well known for its mitogenic and morphogenic functions during development, and HH signaling continues in discrete populations of cells within many adult mammalian tissues. Growing evidence indicates that HH regulates diverse quiescent stem cell populations, but the exact roles that HH signaling plays in adult organ homeostasis and regeneration remain poorly understood. Here, we review recently identified functions of HH in modulating the behavior of tissue-specific adult stem and progenitor cells during homeostasis, regeneration and disease. We conclude that HH signaling is a key factor in the regulation of adult tissue homeostasis and repair, acting via multiple different routes to regulate distinct cellular outcomes, including maintenance of plasticity, in a context-dependent manner. PMID:25183867

Cell-stimulation therapy of lateral epicondylitis with frequency-modulated low-intensity electric current.

PubMed

Aliyev, R M; Geiger, G

2012-03-01

In addition to the routine therapy, the patients with lateral epicondylitis included into experimental group were subjected to a 12-week cell-stimulation therapy with low-intensity frequency-modulated electric current. The control group received the same routine therapy and sham stimulation (the therapeutic apparatus was not energized). The efficiency of this microcurrent therapy was estimated by comparing medical indices before therapy and at the end of a 12-week therapeutic course using a 10-point pain severity numeric rating scale (NRS) and Roles-Maudsley pain score. The study revealed high therapeutic efficiency of cell-stimulation with low-intensity electric current resulting probably from up-regulation of intracellular transmitters, interleukins, and prostaglandins playing the key role in the regulation of inflammation.

Metabolomic analysis of pancreatic β-cell insulin release in response to glucose.

PubMed

Huang, Mei; Joseph, Jamie W

2012-01-01

Defining the key metabolic pathways that are important for fuel-regulated insulin secretion is critical to providing a complete picture of how nutrients regulate insulin secretion. We have performed a detailed metabolomics study of the clonal β-cell line 832/13 using a gas chromatography-mass spectrometer (GC-MS) to investigate potential coupling factors that link metabolic pathways to insulin secretion. Mid-polar and polar metabolites, extracted from the 832/13 β-cells, were derivatized and then run on a GC/MS to identify and quantify metabolite concentrations. Three hundred fifty-five out of 527 chromatographic peaks could be identified as metabolites by our metabolomic platform. These identified metabolites allowed us to perform a systematic analysis of key pathways involved in glucose-stimulated insulin secretion (GSIS). Of these metabolites, 41 were consistently identified as biomarker for GSIS by orthogonal partial least-squares (OPLS). Most of the identified metabolites are from common metabolic pathways including glycolytic, sorbitol-aldose reductase pathway, pentose phosphate pathway, and the TCA cycle suggesting these pathways play an important role in GSIS. Lipids and related products were also shown to contribute to the clustering of high glucose sample groups. Amino acids lysine, tyrosine, alanine and serine were upregulated by glucose whereas aspartic acid was downregulated by glucose suggesting these amino acids might play a key role in GSIS. In summary, a coordinated signaling cascade elicited by glucose metabolism in pancreatic β-cells is revealed by our metabolomics platform providing a new conceptual framework for future research and/or drug discovery.

The TRPM1 Channel Is Required for Development of the Rod ON Bipolar Cell-AII Amacrine Cell Pathway in the Retinal Circuit.

PubMed

Kozuka, Takashi; Chaya, Taro; Tamalu, Fuminobu; Shimada, Mariko; Fujimaki-Aoba, Kayo; Kuwahara, Ryusuke; Watanabe, Shu-Ichi; Furukawa, Takahisa

2017-10-11

Neurotransmission plays an essential role in neural circuit formation in the central nervous system (CNS). Although neurotransmission has been recently clarified as a key modulator of retinal circuit development, the roles of individual synaptic transmissions are not yet fully understood. In the current study, we investigated the role of neurotransmission from photoreceptor cells to ON bipolar cells in development using mutant mouse lines of both sexes in which this transmission is abrogated. We found that deletion of the ON bipolar cation channel TRPM1 results in the abnormal contraction of rod bipolar terminals and a decreased number of their synaptic connections with amacrine cells. In contrast, these histological alterations were not caused by a disruption of total glutamate transmission due to loss of the ON bipolar glutamate receptor mGluR6 or the photoreceptor glutamate transporter VGluT1. In addition, TRPM1 deficiency led to the reduction of total dendritic length, branch numbers, and cell body size in AII amacrine cells. Activated Goα, known to close the TRPM1 channel, interacted with TRPM1 and induced the contraction of rod bipolar terminals. Furthermore, overexpression of Channelrhodopsin-2 partially rescued rod bipolar cell development in the TRPM1 -/- retina, whereas the rescue effect by a constitutively closed form of TRPM1 was lower than that by the native form. Our results suggest that TRPM1 channel opening is essential for rod bipolar pathway establishment in development. SIGNIFICANCE STATEMENT Neurotransmission has been recognized recently as a key modulator of retinal circuit development in the CNS. However, the roles of individual synaptic transmissions are not yet fully understood. In the current study, we focused on neurotransmission between rod photoreceptor cells and rod bipolar cells in the retina. We used genetically modified mouse models which abrogate each step of neurotransmission: presynaptic glutamate release, postsynaptic glutamate reception, or transduction channel function. We found that the TRPM1 transduction channel is required for the development of rod bipolar cells and their synaptic formation with subsequent neurons, independently of glutamate transmission. This study advances our understanding of neurotransmission-mediated retinal circuit refinement. Copyright © 2017 the authors 0270-6474/17/379889-12$15.00/0.

Nuclear and Membrane Actions of Estrogen Receptor Alpha: Contribution to the Regulation of Energy and Glucose Homeostasis.

PubMed

Guillaume, Maeva; Montagner, Alexandra; Fontaine, Coralie; Lenfant, Françoise; Arnal, Jean-François; Gourdy, Pierre

2017-01-01

Estrogen receptor alpha (ERα) has been demonstrated to play a key role in reproduction but also to exert numerous functions in nonreproductive tissues. Accordingly, ERα is now recognized as a key regulator of energy homeostasis and glucose metabolism and mediates the protective effects of estrogens against obesity and type 2 diabetes. This chapter attempts to summarize our current understanding of the mechanisms of ERα activation and their involvement in the modulation of energy balance and glucose metabolism. We first focus on the experimental studies that constitute the basis of the understanding of ERα as a nuclear receptor and more specifically on the key roles played by its two activation functions (AFs). We depict the consequences of the selective inactivation of these AFs in mouse models, which further underline the prominent role of nuclear ERα in the prevention of obesity and diabetes, as on the reproductive tract and the vascular system. Besides these nuclear actions, a fraction of ERα is associated with the plasma membrane and activates nonnuclear signaling from this site. Such rapid effects, called membrane-initiated steroid signals (MISS), have been characterized in a variety of cell lines and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS as well as the generation of mice expressing an ERα protein impeded for membrane localization has just begun to unravel the physiological role of MISS in vivo and their contribution to ERα-mediated metabolic protection. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators.

The influence of opioids on urokinase plasminogen activator on protein and mRNA level in MCF-7 breast cancer cell line.

PubMed

Gach, Katarzyna; Szemraj, Janusz; Fichna, Jakub; Piestrzeniewicz, Mariola; Delbro, Dick S; Janecka, Anna

2009-10-01

Urokinase plasminogen activator plays a key role in tumor-associated processes, increasing cancer cell invasion and metastasis, and is therefore used as a marker in cancer prognosis. In this study, we have determined the effect of mu-opioid receptor agonists and antagonists on the urokinase plasminogen activator secretion in MCF-7 cell line. It was shown that mu-opioid receptor agonists, such as morphine and endomorphins, greatly stimulate urokinase plasminogen activator secretion, while naloxone and MOR-selective antagonists elicit the opposite effect. The same tendency was observed also on the urokinase plasminogen activator mRNA level. However, neither agonists nor antagonists had any effect on proliferation of MCF-7 cells. The findings reported in this study may be useful in designing further experiments aimed at elucidating the role of the opioid system in cancer cells.

Possible Mitochondria-Associated Enzymatic Role in Non-Hodgkin Lymphoma Residual Disease

PubMed Central

Kusao, Ian; Troelstrup, David; Shiramizu, Bruce

2009-01-01

Background The mechanisms responsible for resistant or recurrent disease in childhood non-Hodgkin lymphoma (NHL) are not yet fully understood. A unique mechanism suggesting the role of the mitochondria as the key energy source responsible for residual cells has been assessed in the clinical setting on specimens from patients on therapy were found to have increased copies of mitochondrial DNA (mtDNA) associated with positive minimal residual disease and/or persistent disease (MRD/PD) status. The potential role of mtDNA in MRD/PD emphasizes queries into the contributions of relevant enzymatic pathways responsible for MRD/PD. This study hypothesized that in an in-vitro model, recovering or residual cells from chemotoxicity will exhibit an increase in both citrate synthase and isocitrate dehydrogenase expression and decrease in succinate dehydrogenase expression. Procedure Ramos cells (Burkitt lymphoma cell line) were exposed to varying concentrations of doxorubicin and vincristine for 1 hr; and allowing for recovery in culture over a 7-day period. cDNA was extracted on days 1 and 7 of the cell culture period to assess the relative expression of the aforementioned genes. Results Increase citrate synthase, increase isocitrate dehydrogenase and decrease succinate dehydrogenase expressions were found in recovering Ramos cells. Conclusion Recovering lymphoma cells appear to compensate by regulating enzymatic levels of appropriate genes in the Krebs Cycle suggesting an important role of the mitochondria in the presence of residual cells. PMID:19936279

APLP2 regulates neuronal stem cell differentiation during cortical development.

PubMed

Shariati, S Ali M; Lau, Pierre; Hassan, Bassem A; Müller, Ulrike; Dotti, Carlos G; De Strooper, Bart; Gärtner, Annette

2013-03-01

Expression of amyloid precursor protein (APP) and its two paralogues, APLP1 and APLP2 during brain development coincides with key cellular events such as neuronal differentiation and migration. However, genetic knockout and shRNA studies have led to contradictory conclusions about their role during embryonic brain development. To address this issue, we analysed in depth the role of APLP2 during neurogenesis by silencing APLP2 in vivo in an APP/APLP1 double knockout mouse background. We find that under these conditions cortical progenitors remain in their undifferentiated state much longer, displaying a higher number of mitotic cells. In addition, we show that neuron-specific APLP2 downregulation does not impact the speed or position of migrating excitatory cortical neurons. In summary, our data reveal that APLP2 is specifically required for proper cell cycle exit of neuronal progenitors, and thus has a distinct role in priming cortical progenitors for neuronal differentiation.

Regulation of tomato fruit pericarp development by an interplay between CDKB and CDKA1 cell cycle genes

PubMed Central

Czerednik, Anna; Busscher, Marco; Bielen, Bram A.M.; Wolters-Arts, Mieke; de Maagd, Ruud A.; Angenent, Gerco C.

2012-01-01

Growth of tomato fruits is determined by cell division and cell expansion, which are tightly controlled by factors that drive the core cell cycle. The cyclin-dependent kinases (CDKs) and their interacting partners, the cyclins, play a key role in the progression of the cell cycle. In this study the role of CDKA1, CDKB1, and CDKB2 in fruit development was characterized by fruit-specific overexpression and down-regulation. CDKA1 is expressed in the pericarp throughout development, but is strongly up-regulated in the outer pericarp cell layers at the end of the growth period, when CDKB gene expression has ceased. Overexpression of the CDKB genes at later stages of development and the down-regulation of CDKA1 result in a very similar fruit phenotype, showing a reduction in the number of cell layers in the pericarp and alterations in the desiccation of the fruits. Expression studies revealed that CDKA1 is down-regulated by the expression of CDKB1/2 in CDKB1 and CDKB2 overexpression mutants, suggesting opposite roles for these types of CDK proteins in tomato pericarp development. PMID:22282536

Role of protein phosphomannosylation in the Candida tropicalis-macrophage interaction.

PubMed

Hernández-Chávez, Marco J; Franco, Bernardo; Clavijo-Giraldo, Diana M; Hernández, Nahúm V; Estrada-Mata, Eine; Mora-Montes, Héctor Manuel

2018-04-27

Candida tropicalis is an opportunistic fungal pathogen responsible for mucosal and systemic infections. The cell wall is the initial contact point between a fungal cell and the host immune system, and mannoproteins are important components that play key roles when interacting with host cells. In C. albicans, mannans are modified by mannosyl-phosphate moieties, named phosphomannans, which can work as molecular scaffolds to synthesize β1,2-mannooligosaccharides, and MNN4 is a positive regulator of the phosphomannosylation pathway. Here, we showed that C. tropicalis also displays phosphomannans on the cell surface, but the amount of this cell wall component varies depending on the fungal strain. We also identified a functional ortholog of CaMNN4 in C. tropicalis. Disruption of this gene caused depletion of phosphomannan content. The C. tropicalis mnn4Δ did not show defects in the ability to stimulate cytokine production by human mononuclear cells but displayed virulence attenuation in an insect model of candidiasis. When the mnn4Δ-macrophage interaction was analyzed, results showed that presence of cell wall phosphomannan was critical for C. tropicalis phagocytosis. Finally, our results strongly suggest a differential role for phosphomannans during phagocytosis of C. albicans and C. tropicalis.

Directional cell elongation through filopodia-steered lamellipodial extension on patterned silk fibroin films.

PubMed

You, Renchuan; Li, Xiufang; Luo, Zuwei; Qu, Jing; Li, Mingzhong

2015-03-05

Micropatterned biomaterials have been used to direct cell alignment for specific tissue engineering applications. However, the understanding of how cells respond to guidance cues remains limited. Plasticity in protrusion formation has been proposed to enable cells to adapt their motility mode to microenvironment. In this study, the authors investigated the key role of protrusion response in cell guidance on patterned silk fibroin films. The results revealed that the ability to transform between filopodia and small lamellipodia played important roles in directional cell guidance. Filopodia did not show directional extension on patterned substrates prior to spreading, but they transduced topographical cues to the cell to trigger the formation of small lamellipodia along the direction of a microgrooved or parallel nanofiber pattern. The polar lamellipodia formation provided not only a path with directionality, but a driving force for directional cell elongation. Moreover, aligned nanofibers coating provided better mechanical support for the traction of filopodia and lamellipodia, promoting cell attachment, spreading, and migration. This study provides new insight into how cells respond to guidance cues and how filopodia and lamellipodia control cell contact guidance on micropatterned biomaterial surfaces.

Regulatory RNA Key Player in p53-Mediated Apoptosis in Embryonic Stem Cells | Center for Cancer Research

Cancer.gov

Embryonic stem cells (ESCs) must maintain the integrity of their genomes or risk passing potentially deleterious mutations on to numerous tissues. Thus, ESCs have a unique genome surveillance system and easily undergo apoptosis or differentiation when DNA damage is detected. The protein p53 is known to promote differentiation in mouse ESCs (mESCs), but its role in DNA

National Trauma Institute: A National Coordinating Center for Trauma Research Funding

DTIC Science & Technology

2013-10-01

identified as the key regulator of iron homeostasis, and plays a major role in how and why anemia develops. Hepcidin reduces iron availability by: (1...cells. High levels of hepcidin induce a state of functional iron deficiency . Hepcidin is increased in states of inflammation, and likely plays an...elevated in trauma, this will confirm that inability to use iron stores is key to the anemia of trauma. Dr Napolitano suspects that hepcidin will be

FOXP3 over-expression inhibits melanoma tumorigenesis via effects on proliferation and apoptosis.

PubMed

Tan, BeeShin; Anaka, Matthew; Deb, Siddhartha; Freyer, Claudia; Ebert, Lisa M; Chueh, Anderly C; Al-Obaidi, Sheren; Behren, Andreas; Jayachandran, Aparna; Cebon, Jonathan; Chen, Weisan; Mariadason, John M

2014-01-15

The Forkhead box P3 (FOXP3) transcription factor is the key driver of regulatory T cell (Treg cells) differentiation and immunosuppressive function. In addition, FOXP3 has been reported to be expressed in many tumors, including melanoma. However, its role in tumorigenesis is conflicting, with both tumor suppressive and tumor promoting functions described. The aim of the current study was to characterize the expression and function of FOXP3 in melanoma. FOXP3 expression was detected by immunohistochemistry (IHC) in 12% (18/146) of stage III and IV melanomas. However expression was confined to fewer than 1% of cells in these tumors. Stable over-expression of FOXP3 in the SK-MEL-28 melanoma cell line reduced cell proliferation and clonogenicity in vitro, and reduced xenograft growth in vivo. FOXP3 over-expression also increased pigmentation and the rate of apoptosis of SK-MEL-28 cells. Based on its infrequent expression in human melanoma, and its growth inhibitory and pro-apoptotic effect in over-expressing melanoma cells, we conclude that FOXP3 is not likely to be a key tumor suppressor or promoter in melanoma.

Incretin Receptor Null Mice Reveal Key Role of GLP-1 but Not GIP in Pancreatic Beta Cell Adaptation to Pregnancy

PubMed Central

Moffett, R. Charlotte; Vasu, Srividya; Thorens, Bernard; Drucker, Daniel J.; Flatt, Peter R.

2014-01-01

Islet adaptations to pregnancy were explored in C57BL6/J mice lacking functional receptors for glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). Pregnant wild type mice and GIPRKO mice exhibited marked increases in islet and beta cell area, numbers of medium/large sized islets, with positive effects on Ki67/Tunel ratio favouring beta cell growth and enhanced pancreatic insulin content. Alpha cell area and glucagon content were unchanged but prohormone convertases PC2 and PC1/3 together with significant amounts of GLP-1 and GIP were detected in alpha cells. Knockout of GLP-1R abolished these islet adaptations and paradoxically decreased pancreatic insulin, GLP-1 and GIP. This was associated with abolition of normal pregnancy-induced increases in plasma GIP, L-cell numbers, and intestinal GIP and GLP-1 stores. These data indicate that GLP-1 but not GIP is a key mediator of beta cell mass expansion and related adaptations in pregnancy, triggered in part by generation of intra-islet GLP-1. PMID:24927416

Ebola virus infection kinetics in chimeric mice reveal a key role of T cells as barriers for virus dissemination

PubMed Central

Lüdtke, Anja; Ruibal, Paula; Wozniak, David M.; Pallasch, Elisa; Wurr, Stephanie; Bockholt, Sabrina; Gómez-Medina, Sergio; Qiu, Xiangguo; Kobinger, Gary P.; Rodríguez, Estefanía; Günther, Stephan; Krasemann, Susanne; Idoyaga, Juliana; Oestereich, Lisa; Muñoz-Fontela, César

2017-01-01

Ebola virus (EBOV) causes severe systemic disease in humans and non-human primates characterized by high levels of viremia and virus titers in peripheral organs. The natural portals of virus entry are the mucosal surfaces and the skin where macrophages and dendritic cells (DCs) are primary EBOV targets. Due to the migratory properties of DCs, EBOV infection of these cells has been proposed as a necessary step for virus dissemination via draining lymph nodes and blood. Here we utilize chimeric mice with competent hematopoietic-driven immunity, to show that EBOV primarily infects CD11b+ DCs in non-lymphoid and lymphoid tissues, but spares the main cross-presenting CD103+ DC subset. Furthermore, depletion of CD8 and CD4 T cells resulted in loss of early control of virus replication, viremia and fatal Ebola virus disease (EVD). Thus, our findings point out at T cell function as a key determinant of EVD progress and outcome. PMID:28256637

Find-me and eat-me signals in apoptotic cell clearance: progress and conundrums

PubMed Central

2010-01-01

Everyday we turnover billions of cells. The quick, efficient, and immunologically silent disposal of the dying cells requires a coordinated orchestration of multiple steps, through which phagocytes selectively recognize and engulf apoptotic cells. Recent studies have suggested an important role for soluble mediators released by apoptotic cells that attract phagocytes (“find-me” signals). New information has also emerged on multiple receptors that can recognize phosphatidylserine, the key “eat-me” signal exposed on the surface of apoptotic cells. This perspective discusses recent exciting progress, gaps in our understanding, and the conflicting issues that arise from the newly acquired knowledge. PMID:20805564

Modelling heterogeneous interfaces for solar water splitting

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

Pham, Tuan Anh; Ping, Yuan; Galli, Giulia

2017-01-09

The generation of hydrogen from water and sunlight others a promising approach for producing scalable and sustainable carbon-free energy. The key of a successful solar-to-fuel technology is the design of efficient, long-lasting and low-cost photoelectrochemical cells, which are responsible for absorbing sunlight and driving water splitting reactions. To this end, a detailed understanding and control of heterogeneous interfaces between photoabsorbers, electrolytes and catalysts present in photoelectrochemical cells is essential. Here we review recent progress and open challenges in predicting physicochemical properties of heterogeneous interfaces for solar water splitting applications using first-principles-based approaches, and highlights the key role of these calculationsmore » in interpreting increasingly complex experiments.« less

Epigenetic reprogramming - is deamination key to active DNA demethylation?

PubMed Central

Teperek-Tkacz, Marta; Pasque, Vincent; Gentsch, George; Ferguson-Smith, Anne C.

2013-01-01

DNA demethylation processes are important for reproduction being central in epigenetic reprogramming during embryonic and germ cell development. While the enzymes methylating DNA have been known for many years, identification of factors capable of mediating active DNA demethylation has been challenging. Recent findings suggest that cytidine deaminases may be key players in active DNA demethylation. One of the most investigated candidates is AID (activation-induced cytidine deaminase) best known for its role in generating secondary antibody diversity in B cells. We evaluate evidence for cytidine deaminases in DNA demethylation pathways in vertebrates and discuss possible models for their targeting and activity regulation. These findings are also considered alongside alternative demethylation pathways involving hydroxymethylation. PMID:21911441

Taste receptors of the gut: emerging roles in health and disease.

PubMed

Depoortere, Inge

2014-01-01

Recent progress in unravelling the nutrient-sensing mechanisms in the taste buds of the tongue has triggered studies on the existence and role of chemosensory cells in the gut. Indeed, the gastrointestinal tract is the key interface between food and the human body and can sense basic tastes in much the same way as the tongue, through the use of similar G-protein-coupled taste receptors. These receptors 'taste' the luminal content and transmit signals that regulate nutrient transporter expression and nutrient uptake, and also the release of gut hormones and neurotransmitters involved in the regulation of energy and glucose homeostasis. Hence, they play a prominent role in the communication between the lumen, epithelium, smooth muscle cells, afferent nerve fibres and the brain to trigger adaptive responses that affect gastrointestinal function, food intake and glucose metabolism. This review summarises how sensing of nutrients by taste receptors along the gut plays a key role in the process of digestion, and how disturbances or adaptations of these chemosensory signalling pathways may contribute to the induction or resolution of a number of pathological conditions related to diabetes, obesity, or diet-induced symptom generation in irritable bowel syndrome. Targeting these receptors may represent a promising novel route for the treatment of a number of these diseases.

Constitutive BAK activation as a determinant of drug sensitivity in malignant lymphohematopoietic cells.

PubMed

Dai, Haiming; Ding, Husheng; Meng, X Wei; Peterson, Kevin L; Schneider, Paula A; Karp, Judith E; Kaufmann, Scott H

2015-10-15

Mitochondrial outer membrane permeabilization (MOMP), a key step in the intrinsic apoptotic pathway, is incompletely understood. Current models emphasize the role of BH3-only BCL2 family members in BAX and BAK activation. Here we demonstrate concentration-dependent BAK autoactivation under cell-free conditions and provide evidence that this autoactivation plays a key role in regulating the intrinsic apoptotic pathway in intact cells. In particular, we show that up to 80% of BAK (but not BAX) in lymphohematopoietic cell lines is oligomerized and bound to anti-apoptotic BCL2 family members in the absence of exogenous death stimuli. The extent of this constitutive BAK oligomerization is diminished by BAK knockdown and unaffected by BIM or PUMA down-regulation. Further analysis indicates that sensitivity of cells to BH3 mimetics reflects the identity of the anti-apoptotic proteins to which BAK is constitutively bound, with extensive BCLXL•BAK complexes predicting navitoclax sensitivity, and extensive MCL1•BAK complexes predicting A1210477 sensitivity. Moreover, high BAK expression correlates with sensitivity of clinical acute myelogenous leukemia to chemotherapy, whereas low BAK levels correlate with resistance and relapse. Collectively, these results inform current understanding of MOMP and provide new insight into the ability of BH3 mimetics to induce apoptosis without directly activating BAX or BAK. © 2015 Dai et al.; Published by Cold Spring Harbor Laboratory Press.

An adipoinductive role of inflammation in adipose tissue engineering: key factors in the early development of engineered soft tissues.

PubMed

Lilja, Heidi E; Morrison, Wayne A; Han, Xiao-Lian; Palmer, Jason; Taylor, Caroline; Tee, Richard; Möller, Andreas; Thompson, Erik W; Abberton, Keren M

2013-05-15

Tissue engineering and cell implantation therapies are gaining popularity because of their potential to repair and regenerate tissues and organs. To investigate the role of inflammatory cytokines in new tissue development in engineered tissues, we have characterized the nature and timing of cell populations forming new adipose tissue in a mouse tissue engineering chamber (TEC) and characterized the gene and protein expression of cytokines in the newly developing tissues. EGFP-labeled bone marrow transplant mice and MacGreen mice were implanted with TEC for periods ranging from 0.5 days to 6 weeks. Tissues were collected at various time points and assessed for cytokine expression through ELISA and mRNA analysis or labeled for specific cell populations in the TEC. Macrophage-derived factors, such as monocyte chemotactic protein-1 (MCP-1), appear to induce adipogenesis by recruiting macrophages and bone marrow-derived precursor cells to the TEC at early time points, with a second wave of nonbone marrow-derived progenitors. Gene expression analysis suggests that TNFα, LCN-2, and Interleukin 1β are important in early stages of neo-adipogenesis. Increasing platelet-derived growth factor and vascular endothelial cell growth factor expression at early time points correlates with preadipocyte proliferation and induction of angiogenesis. This study provides new information about key elements that are involved in early development of new adipose tissue.

Effects of Telomerase and Telomere Length on Epidermal Stem Cell Behavior

NASA Astrophysics Data System (ADS)

Flores, Ignacio; Cayuela, María L.; Blasco, María A.

2005-08-01

A key process in organ homeostasis is the mobilization of stem cells out of their niches. We show through analysis of mouse models that telomere length, as well as the catalytic component of telomerase, Tert, are critical determinants in the mobilization of epidermal stem cells. Telomere shortening inhibited mobilization of stem cells out of their niche, impaired hair growth, and resulted in suppression of stem cell proliferative capacity in vitro. In contrast, Tert overexpression in the absence of changes in telomere length promoted stem cell mobilization, hair growth, and stem cell proliferation in vitro. The effects of telomeres and telomerase on stem cell biology anticipate their role in cancer and aging.

Loss of centrioles causes chromosomal instability in vertebrate somatic cells.

PubMed

Sir, Joo-Hee; Pütz, Monika; Daly, Owen; Morrison, Ciaran G; Dunning, Mark; Kilmartin, John V; Gergely, Fanni

2013-12-09

Most animal cells contain a centrosome, which comprises a pair of centrioles surrounded by an ordered pericentriolar matrix (PCM). Although the role of this organelle in organizing the mitotic spindle poles is well established, its precise contribution to cell division and cell survival remains a subject of debate. By genetically ablating key components of centriole biogenesis in chicken DT40 B cells, we generated multiple cell lines that lack centrioles. PCM components accumulated in acentriolar microtubule (MT)-organizing centers but failed to adopt a higher-order structure, as shown by three-dimensional structured illumination microscopy. Cells without centrioles exhibited both a delay in bipolar spindle assembly and a high rate of chromosomal instability. Collectively, our results expose a vital role for centrosomes in establishing a mitotic spindle geometry that facilitates correct kinetochore-MT attachments. We propose that centrosomes are essential in organisms in which rapid segregation of a large number of chromosomes needs to be attained with fidelity.

Paracrine control of tissue regeneration and cell proliferation by Caspase-3

PubMed Central

Boland, K; Flanagan, L; Prehn, J HM

2013-01-01

Executioner caspases such as Caspase-3 and Caspase-7 have long been recognised as the key proteases involved in cell demolition during apoptosis. Caspase activation also modulates signal transduction inside cells, through activation or inactivation of kinases, phosphatases and other signalling molecules. Interestingly, a series of recent studies have demonstrated that caspase activation may also influence signal transduction and gene expression changes in neighbouring cells that themselves did not activate caspases. This review describes the physiological relevance of paracrine Caspase-3 signalling for developmental processes, tissue homeostasis and tissue regeneration, and discusses the role of soluble factors and microparticles in mediating these paracrine activities. While non-cell autonomous control of tissue regeneration by Caspase-3 may represent an important process for maintaining tissue homeostasis, it may limit the efficiency of current cancer therapy by promoting cell proliferation in those cancer cells resistant to radio- or chemotherapy. We discuss recent evidence in support of such a role for Caspase-3, and discuss its therapeutic implication. PMID:23846227

Cylindromatosis mediates neuronal cell death in vitro and in vivo.

PubMed

Ganjam, Goutham K; Terpolilli, Nicole Angela; Diemert, Sebastian; Eisenbach, Ina; Hoffmann, Lena; Reuther, Christina; Herden, Christiane; Roth, Joachim; Plesnila, Nikolaus; Culmsee, Carsten

2018-01-19

The tumor-suppressor cylindromatosis (CYLD) is a deubiquitinating enzyme and key regulator of cell proliferation and inflammation. A genome-wide siRNA screen linked CYLD to receptor interacting protein-1 (RIP1) kinase-mediated necroptosis; however, the exact mechanisms of CYLD-mediated cell death remain unknown. Therefore, we investigated the precise role of CYLD in models of neuronal cell death in vitro and evaluated whether CYLD deletion affects brain injury in vivo. In vitro, downregulation of CYLD increased RIP1 ubiquitination, prevented RIP1/RIP3 complex formation, and protected neuronal cells from oxidative death. Similar protective effects were achieved by siRNA silencing of RIP1 or RIP3 or by pharmacological inhibition of RIP1 with necrostatin-1. In vivo, CYLD knockout mice were protected from trauma-induced brain damage compared to wild-type littermate controls. These findings unravel the mechanisms of CYLD-mediated cell death signaling in damaged neurons in vitro and suggest a cell death-mediating role of CYLD in vivo.

Clathrin-Independent Endocytosis Suppresses Cancer Cell Blebbing and Invasion.

PubMed

Holst, Mikkel Roland; Vidal-Quadras, Maite; Larsson, Elin; Song, Jie; Hubert, Madlen; Blomberg, Jeanette; Lundborg, Magnus; Landström, Maréne; Lundmark, Richard

2017-08-22

Cellular blebbing, caused by local alterations in cell-surface tension, has been shown to increase the invasiveness of cancer cells. However, the regulatory mechanisms balancing cell-surface dynamics and bleb formation remain elusive. Here, we show that an acute reduction in cell volume activates clathrin-independent endocytosis. Hence, a decrease in surface tension is buffered by the internalization of the plasma membrane (PM) lipid bilayer. Membrane invagination and endocytosis are driven by the tension-mediated recruitment of the membrane sculpting and GTPase-activating protein GRAF1 (GTPase regulator associated with focal adhesion kinase-1) to the PM. Disruption of this regulation by depleting cells of GRAF1 or mutating key phosphatidylinositol-interacting amino acids in the protein results in increased cellular blebbing and promotes the 3D motility of cancer cells. Our data support a role for clathrin-independent endocytic machinery in balancing membrane tension, which clarifies the previously reported role of GRAF1 as a tumor suppressor. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Involvement of polyubiquitin chains via specific chain linkages in stress response in mammalian cells.

PubMed

Fujimuro, Masahiro; Nishiya, Tadashi; Nomura, Yasuyuki; Yokosawa, Hideyoshi

2005-12-01

Polyubiquitination plays key roles in various proteasome-dependent and independent cellular events. To elucidate roles in stress response of polyubiquitin chains formed via specific chain linkages in mammalian cells, we established NIH3T3 stable cell lines that are capable of conditionally expressing K29R, K48R and K63R ubiquitin mutants, in which the Lys29, Lys48 and Lys63 residues of ubiquitin had been changed to Arg, and we examined the effects of various stresses on their cell viabilities. The expression of K63R ubiquitin mutant decreased viability of the cells post-exposed to ethanol, H(2)O(2) and methyl methanesulfonate (MMS), while that of K48R mutant decreased viability of the cells post-exposed to heat shock as well as ethanol, H(2)O(2) and MMS. Thus, these results suggest that polyubiquitin chains formed via specific chain linkages are involved in the respective stress responses in mammalian cells.

Exosomes carrying immunoinhibitory proteins and their role in cancer.

PubMed

Whiteside, T L

2017-09-01

Recent emergence of exosomes as information carriers between cells has introduced us to a new previously unknown biological communication system. Multi-directional cross-talk mediated by exosomes carrying proteins, lipids and nucleic acids between normal cells, cells harbouring a pathogen or cancer and immune cells has been instrumental in determining outcomes of physiological as well as pathological conditions. Exosomes play a key role in the broad spectrum of human diseases. In cancer, tumour-derived exosomes carry multiple immunoinhibitory signals, disable anti-tumour immune effector cells and promote tumour escape from immune control. Exosomes delivering negative signals to immune cells in cancer, viral infections, autoimmune or other diseases may interfere with therapy and influence outcome. Exosomes can activate tissue cells to produce inhibitory factors and thus can suppress the host immune responses indirectly. Exosomes also promise to be non-invasive disease biomarkers with a dual capability to provide insights into immune dysfunction as well as disease progression and outcome. © 2017 British Society for Immunology.

Dysregulated choline metabolism in T-cell lymphoma: role of choline kinase-α and therapeutic targeting

PubMed Central

Xiong, J; Bian, J; Wang, L; Zhou, J-Y; Wang, Y; Zhao, Y; Wu, L-L; Hu, J-J; Li, B; Chen, S-J; Yan, C; Zhao, W-L

2015-01-01

Cancer cells have distinct metabolomic profile. Metabolic enzymes regulate key oncogenic signaling pathways and have an essential role on tumor progression. Here, serum metabolomic analysis was performed in 45 patients with T-cell lymphoma (TCL) and 50 healthy volunteers. The results showed that dysregulation of choline metabolism occurred in TCL and was related to tumor cell overexpression of choline kinase-α (Chokα). In T-lymphoma cells, pharmacological and molecular silencing of Chokα significantly decreased Ras-GTP activity, AKT and ERK phosphorylation and MYC oncoprotein expression, leading to restoration of choline metabolites and induction of tumor cell apoptosis/necropotosis. In a T-lymphoma xenograft murine model, Chokα inhibitor CK37 remarkably retarded tumor growth, suppressed Ras-AKT/ERK signaling, increased lysophosphatidylcholine levels and induced in situ cell apoptosis/necropotosis. Collectively, as a regulatory gene of aberrant choline metabolism, Chokα possessed oncogenic activity and could be a potential therapeutic target in TCL, as well as other hematological malignancies with interrupted Ras signaling pathways. PMID:25768400

The stat3/socs3a pathway is a key regulator of hair cell regeneration in zebrafish. [corrected].

PubMed

Liang, Jin; Wang, Dongmei; Renaud, Gabriel; Wolfsberg, Tyra G; Wilson, Alexander F; Burgess, Shawn M

2012-08-01

All nonmammalian vertebrates studied can regenerate inner ear mechanosensory receptors (i.e., hair cells) (Corwin and Cotanche, 1988; Lombarte et al., 1993; Baird et al., 1996), but mammals possess only a very limited capacity for regeneration after birth (Roberson and Rubel, 1994). As a result, mammals experience permanent deficiencies in hearing and balance once their inner ear hair cells are lost. The mechanisms of hair cell regeneration are poorly understood. Because the inner ear sensory epithelium is highly conserved in all vertebrates (Fritzsch et al., 2007), we chose to study hair cell regeneration mechanism in adult zebrafish, hoping the results would be transferrable to inducing hair cell regeneration in mammals. We defined the comprehensive network of genes involved in hair cell regeneration in the inner ear of adult zebrafish with the powerful transcriptional profiling technique digital gene expression, which leverages the power of next-generation sequencing ('t Hoen et al., 2008). We also identified a key pathway, stat3/socs3, and demonstrated its role in promoting hair cell regeneration through stem cell activation, cell division, and differentiation. In addition, transient pharmacological inhibition of stat3 signaling accelerated hair cell regeneration without overproducing cells. Taking other published datasets into account (Sano et al., 1999; Schebesta et al., 2006; Dierssen et al., 2008; Riehle et al., 2008; Zhu et al., 2008; Qin et al., 2009), we propose that the stat3/socs3 pathway is a key response in all tissue regeneration and thus an important therapeutic target for a broad application in tissue repair and injury healing.

Roles for miR-375 in Neuroendocrine Differentiation and Tumor Suppression via Notch Pathway Suppression in Merkel Cell Carcinoma.

PubMed

Abraham, Karan J; Zhang, Xiao; Vidal, Ricardo; Paré, Geneviève C; Feilotter, Harriet E; Tron, Victor A

2016-04-01

Dysfunction of key miRNA pathways regulating basic cellular processes is a common driver of many cancers. However, the biological roles and/or clinical applications of such pathways in Merkel cell carcinoma (MCC), a rare but lethal cutaneous neuroendocrine (NE) malignancy, have yet to be determined. Previous work has established that miR-375 is highly expressed in MCC tumors, but its biological role in MCC remains unknown. Herein, we show that elevated miR-375 expression is a specific feature of well-differentiated MCC cell lines that express NE markers. In contrast, miR-375 is strikingly down-regulated in highly aggressive, undifferentiated MCC cell lines. Enforced miR-375 expression in these cells induced NE differentiation, and opposed cancer cell viability, migration, invasion, and survival, pointing to tumor-suppressive roles for miR-375. Mechanistically, miR-375-driven phenotypes were caused by the direct post-transcriptional repression of multiple Notch pathway proteins (Notch2 and RBPJ) linked to cancer and regulation of cell fate. Thus, we detail a novel molecular axis linking tumor-suppressive miR-375 and Notch with NE differentiation and cancer cell behavior in MCC. Our findings identify miR-375 as a putative regulator of NE differentiation, provide insight into the cell of origin of MCC, and suggest that miR-375 silencing may promote aggressive cancer cell behavior through Notch disinhibition. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Airway Hyperresponsiveness through Synergy of γδ T Cells and NKT Cells1

PubMed Central

Jin, Niyun; Miyahara, Nobuaki; Roark, Christina L.; French, Jena D.; Aydintug, M. Kemal; Matsuda, Jennifer L.; Gapin, Laurent; O'Brien, Rebecca L.; Gelfand, Erwin W.; Born, Willi K.

2015-01-01

Mice sensitized and challenged with OVA were used to investigate the role of innate T cells in the development of allergic airway hyperresponsiveness (AHR). AHR, but not eosinophilic airway inflammation, was induced in T cell-deficient mice by small numbers of cotransferred γδ T cells and invariant NKT cells, whereas either cell type alone was not effective. Only Vγ1+Vδ5+ γδ T cells enhanced AHR. Surprisingly, OVA-specific αβ T cells were not required, revealing a pathway of AHR development mediated entirely by innate T cells. The data suggest that lymphocytic synergism, which is key to the Ag-specific adaptive immune response, is also intrinsic to T cell-dependent innate responses. PMID:17709511

Anti-inflammatory effects of vinpocetine in atherosclerosis and ischemic stroke: a review of the literature.

PubMed

Zhang, Linjie; Yang, Li

2014-12-26

Immune responses play an important role in the pathophysiology of atherosclerosis and ischemic stroke. Atherosclerosis is a common condition that increases the risk of stroke. Hyperlipidemia damages endothelial cells, thus initiating chemokine pathways and the release of inflammatory cytokines-this represents the first step in the inflammatory response to atherosclerosis. Blocking blood flow in the brain leads to ischemic stroke, and deprives neurons of oxygen and energy. Damaged neurons release danger-associated molecular patterns, which promote the activation of innate immune cells and the release of inflammatory cytokines. The nuclear factor κ-light-chain-enhancer of activated B cells κB (NF-κB) pathway plays a key role in the pathogenesis of atherosclerosis and ischemic stroke. Vinpocetine is believed to be a potent anti-inflammatory agent and has been used to treat cerebrovascular disorders. Vinpocetine improves neuronal plasticity and reduces the release of inflammatory cytokines and chemokines from endothelial cells, vascular smooth muscle cells, macrophages, and microglia, by inhibiting the inhibitor of the NF-κB pathway. This review clarifies the anti-inflammatory role of vinpocetine in atherosclerosis and ischemic stroke.

A critical review on gas diffusion micro and macroporous layers degradations for improved membrane fuel cell durability

NASA Astrophysics Data System (ADS)

Lapicque, Francois; Belhadj, Mariem; Bonnet, Caroline; Pauchet, Joël; Thomas, Yohann

2016-12-01

Formerly considered as a secondary component of fuel cell, gas diffusion layers (GDLs) have been shown to have a key role in gas transport to the catalyst layers and in water management: in particular, the microporous layer (MPL) deposited on the diffusion substrate has an active part in water distribution in the membrane electrode assembly and in its efficient removal from the cell. In addition to its perfect design for the targeted application and in combination with the macroporous substrate (MPS), the MPL structure and physicochemical properties have to contribute to the cell durability, which is still considered as insufficient for larger, massive commercialisation of this energy conversion system. The paper is aimed at reviewing the main knowledge gained on the role of the MPL on GDL operation and durability, with investigation of degradation phenomena of both MPL and MPS, together with the role played by the MPL in mitigating the occurrence of degradation phenomena that can occur in the whole fuel cell. In addition to the reviewing purpose, original data on ex-situ degradation of GDL are presented.

Myelination and mTOR

PubMed Central

Figlia, Gianluca; Gerber, Daniel

2017-01-01

Abstract Myelinating cells surround axons to accelerate the propagation of action potentials, to support axonal health, and to refine neural circuits. Myelination is metabolically demanding and, consistent with this notion, mTORC1—a signaling hub coordinating cell metabolism—has been implicated as a key signal for myelination. Here, we will discuss metabolic aspects of myelination, illustrate the main metabolic processes regulated by mTORC1, and review advances on the role of mTORC1 in myelination of the central nervous system and the peripheral nervous system. Recent progress has revealed a complex role of mTORC1 in myelinating cells that includes, besides positive regulation of myelin growth, additional critical functions in the stages preceding active myelination. Based on the available evidence, we will also highlight potential nonoverlapping roles between mTORC1 and its known main upstream pathways PI3K‐Akt, Mek‐Erk1/2, and AMPK in myelinating cells. Finally, we will discuss signals that are already known or hypothesized to be responsible for the regulation of mTORC1 activity in myelinating cells. PMID:29210103

GSK3 Inhibitor-BIO Regulates Proliferation of Immortalized Pancreatic Mesenchymal Stem Cells (iPMSCs)

PubMed Central

Cao, Hui; Chu, Yuankui; Lv, Xiao; Qiu, Pubin; Liu, Chao; Zhang, Huiru; Li, Dan; Peng, Sha; Dou, Zhongying; Hua, Jinlian

2012-01-01

Background The small molecule 6-bromoindirubin-30-oxime (BIO), a glycogen synthase kinase 3 (GSK3) inhibitor, is a pharmacological agent known to maintain self-renewal in human and mouse embryonic stem cells (ESCs). However, the precise role of GSK3 in immortalized pancreatic mesenchymal stem cells (iPMSCs) growth and survival is not completely understood at present. Results To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effect of BIO on iPMSCs. We found that the inactivation of GSK3 by BIO can robustly stimulate iPMSCs proliferation and mass formation as shown by QRT-PCR, western blotting, 5-Bromo-2-deoxyuridine (BrdU) immunostaining assay and tunel assay. However, we did not find the related roles of BIO on β cell differentiation by immunostaining, QRT-PCR assay, glucose-stimulated insulin release and C-peptide content analysis. Conclusions These results suggest that BIO plays a key role in the regulation of cell mass proliferation and maintenance of the undifferentiated state of iPMSCs. PMID:22384031

Hsa-Let-7g miRNA Targets Caspase-3 and Inhibits the Apoptosis Induced by ox-LDL in Endothelial Cells

PubMed Central

Zhang, Yefei; Chen, Naiyun; Zhang, Jihao; Tong, Yaling

2013-01-01

It has been well confirmed ox-LDL plays key roles in the development of atherosclerosis via binding to LOX-1 and inducing apoptosis in vascular endothelial cells. Recent studies have shown ox-LDL can suppress microRNA has-let-7g, which in turn inhibits the ox-LDL induced apoptosis. However, details need to be uncovered. To determine the anti-atherosclerosis effect of microRNA has-let-7g, and to evaluate the possibility of CASP3 as an anti-atherosclerotic drug target by has-let-7g, the present study determined the role of hsa-let-7g miRNA in ox-LDL induced apoptosis in the vascular endothelial cells. We found that miRNA has-let-7g was suppressed during the ox-LDL-induced apoptosis in EAhy926 endothelial cells. In addition, overexpression of has-let-7g negatively regulated apoptosis in the endothelial cells by targeting caspase-3 expression. Therefore, miRNA let-7g may play important role in endothelial apoptosis and atherosclerosis. PMID:24252910

β-Arrestin2 plays a key role in the modulation of the pancreatic beta cell mass in mice.

PubMed

Ravier, Magalie A; Leduc, Michele; Richard, Joy; Linck, Nathalie; Varrault, Annie; Pirot, Nelly; Roussel, Morgane M; Bockaert, Joël; Dalle, Stéphane; Bertrand, Gyslaine

2014-03-01

Beta cell failure due to progressive secretory dysfunction and limited expansion of beta cell mass is a key feature of type 2 diabetes. Beta cell function and mass are controlled by glucose and hormones/neurotransmitters that activate G protein-coupled receptors or receptor tyrosine kinases. We have investigated the role of β-arrestin (ARRB)2, a scaffold protein known to modulate such receptor signalling, in the modulation of beta cell function and mass, with a specific interest in glucagon-like peptide-1 (GLP-1), muscarinic and insulin receptors. β-arrestin2-knockout mice and their wild-type littermates were fed a normal or a high-fat diet (HFD). Glucose tolerance, insulin sensitivity and insulin secretion were assessed in vivo. Beta cell mass was evaluated in pancreatic sections. Free cytosolic [Ca(2+)] and insulin secretion were determined using perifused islets. The insulin signalling pathway was evaluated by western blotting. Arrb2-knockout mice exhibited impaired glucose tolerance and insulin secretion in vivo, but normal insulin sensitivity compared with wild type. Surprisingly, the absence of ARRB2 did not affect glucose-stimulated insulin secretion or GLP-1- and acetylcholine-mediated amplifications from perifused islets, but it decreased the islet insulin content and beta cell mass. Additionally, there was no compensatory beta cell mass expansion through proliferation in response to the HFD. Furthermore, Arrb2 deletion altered the islet insulin signalling pathway. ARRB2 is unlikely to be involved in the regulation of insulin secretion, but it is required for beta cell mass plasticity. Additionally, we provide new insights into the mechanisms involved in insulin signalling in beta cells.

FOXO1 expression in keratinocytes promotes connective tissue healing

PubMed Central

Zhang, Chenying; Lim, Jason; Liu, Jian; Ponugoti, Bhaskar; Alsadun, Sarah; Tian, Chen; Vafa, Rameen; Graves, Dana T.

2017-01-01

Wound healing is complex and highly orchestrated. It is well appreciated that leukocytes, particularly macrophages, are essential for inducing the formation of new connective tissue, which requires the generation of signals that stimulate mesenchymal stem cells (MSC), myofibroblasts and fibroblasts. A key role for keratinocytes in this complex process has yet to be established. To this end, we investigated possible involvement of keratinocytes in connective tissue healing. By lineage-specific deletion of the forkhead box-O 1 (FOXO1) transcription factor, we demonstrate for the first time that keratinocytes regulate proliferation of fibroblasts and MSCs, formation of myofibroblasts and production of collagen matrix in wound healing. This stimulation is mediated by a FOXO1 induced TGFβ1/CTGF axis. The results provide direct evidence that epithelial cells play a key role in stimulating connective tissue healing through a FOXO1-dependent mechanism. Thus, FOXO1 and keratinocytes may be an important therapeutic target where healing is deficient or compromised by a fibrotic outcome. PMID:28220813

SENP1 inhibition induces apoptosis and growth arrest of multiple myeloma cells through modulation of NF-κB signaling

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

Xu, Jun; Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing 100850; Sun, Hui-Yan

2015-05-01

SUMO/sentrin specific protease 1 (Senp1) is an important regulation protease in the protein sumoylation, which affects the cell cycle, proliferation and differentiation. The role of Senp1 mediated protein desumoylation in pathophysiological progression of multiple myeloma is unknown. In this study, we demonstrated that Senp1 is overexpressed and induced by IL-6 in multiple myeloma cells. Lentivirus-mediated Senp1 knockdown triggers apoptosis and reduces viability, proliferation and colony forming ability of MM cells. The NF-κB family members including P65 and inhibitor protein IkBα play important roles in regulation of MM cell survival and proliferation. We further demonstrated that Senp1 inhibition decreased IL-6-induced P65more » and IkBα phosphorylation, leading to inactivation of NF-kB signaling in MM cells. These results delineate a key role for Senp1in IL-6 induced proliferation and survival of MM cells, suggesting it may be a potential new therapeutic target in MM. - Highlights: • Senp1 is overexpressed and induced by IL-6 in multiple myeloma cells. • Senp1 knockdown triggers apoptosis and reduces proliferation of MM cells. • Senp1 inhibition decreased IL-6-induced P65 and IkBα phosphorylation.« less

Morphoregulatory functions of the RNA-binding motif protein 3 in cell spreading, polarity and migration.

PubMed

Pilotte, J; Kiosses, W; Chan, S W; Makarenkova, H P; Dupont-Versteegden, E; Vanderklish, P W

2018-05-09

RNA-binding proteins are emerging as key regulators of transitions in cell morphology. The RNA-binding motif protein 3 (RBM3) is a cold-inducible RNA-binding protein with broadly relevant roles in cellular protection, and putative functions in cancer and development. Several findings suggest that RBM3 has morphoregulatory functions germane to its roles in these contexts. For example, RBM3 helps maintain the morphological integrity of cell protrusions during cell stress and disease. Moreover, it is highly expressed in migrating neurons of the developing brain and in cancer invadopodia, suggesting roles in migration. We here show that RBM3 regulates cell polarity, spreading and migration. RBM3 was present in spreading initiation centers, filopodia and blebs that formed during cell spreading in cell lines and primary myoblasts. Reducing RBM3 triggered exaggerated spreading, increased RhoA expression, and a loss of polarity that was rescued by Rho kinase inhibition and overexpression of CRMP2. High RBM3 expression enhanced the motility of cells migrating by a mesenchymal mode involving extension of long protrusions, whereas RBM3 knockdown slowed migration, greatly reducing the ability of cells to extend protrusions and impairing multiple processes that require directional migration. These data establish novel functions of RBM3 of potential significance to tissue repair, metastasis and development.

Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase.

PubMed

Venkitachalam, Srividya; Chueh, Fu-Yu; Leong, King-Fu; Pabich, Samantha; Yu, Chao-Lan

2011-03-01

Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here, we report that among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine-inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identified the positive regulatory phosphotyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases.

Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase

PubMed Central

VENKITACHALAM, SRIVIDYA; CHUEH, FU-YU; LEONG, KING-FU; PABICH, SAMANTHA; YU, CHAO-LAN

2011-01-01

Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here we report that, among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine–inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identify the positive regulatory phospho-tyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases. PMID:21234523

Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells.

PubMed

Wang, Yizhou; Blatt, Michael R

2011-10-01

Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (malate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (I(Cl)) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect I(Cl), but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of ICl by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with I(Cl) through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes.

Highlights of the advances in basic immunology in 2011.

PubMed

Liu, Juan; Liu, Shuxun; Cao, Xuetao

2012-05-01

In this review, we summarize the major fundamental advances in immunological research reported in 2011. The highlights focus on the improved understanding of key questions in basic immunology, including the initiation and activation of innate responses as well as mechanisms for the development and function of various T-cell subsets. The research includes the identification of novel cytosolic RNA and DNA sensors as well as the identification of the novel regulators of the Toll-like receptor (TLR) and retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling pathway. Moreover, remarkable advances have been made in the developmental and functional properties of innate lymphoid cells (ILCs). Helper T cells and regulatory T (Treg) cells play indispensable roles in orchestrating adaptive immunity. There have been exciting discoveries regarding the regulatory mechanisms of the development of distinct T-cell subsets, particularly Th17 cells and Treg cells. The emerging roles of microRNAs (miRNAs) in T cell immunity are discussed, as is the recent identification of a novel T-cell subset referred to as follicular regulatory T (TFR) cells.

Highlights of the advances in basic immunology in 2011

PubMed Central

Liu, Juan; Liu, Shuxun; Cao, Xuetao

2012-01-01

In this review, we summarize the major fundamental advances in immunological research reported in 2011. The highlights focus on the improved understanding of key questions in basic immunology, including the initiation and activation of innate responses as well as mechanisms for the development and function of various T-cell subsets. The research includes the identification of novel cytosolic RNA and DNA sensors as well as the identification of the novel regulators of the Toll-like receptor (TLR) and retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling pathway. Moreover, remarkable advances have been made in the developmental and functional properties of innate lymphoid cells (ILCs). Helper T cells and regulatory T (Treg) cells play indispensable roles in orchestrating adaptive immunity. There have been exciting discoveries regarding the regulatory mechanisms of the development of distinct T-cell subsets, particularly Th17 cells and Treg cells. The emerging roles of microRNAs (miRNAs) in T cell immunity are discussed, as is the recent identification of a novel T-cell subset referred to as follicular regulatory T (TFR) cells. PMID:22522654

THESEUS 1, FERONIA and relatives: a family of cell wall-sensing receptor kinases?

PubMed

Cheung, Alice Y; Wu, Hen-Ming

2011-12-01

The plant cell wall provides form and integrity to the cell as well as a dynamic interface between a cell and its environment. Therefore mechanisms capable of policing changes in the cell wall, signaling cellular responses including those that would feedback regulate cell wall properties are expected to play important roles in facilitating growth and ensuring survival. Discoveries in the last few years that the Arabidopsis THESEUS 1 receptor-like kinase (RLK) may function as a sensor for cell wall defects to regulate growth and that its relatives FERONIA and ANXURs regulate pollen tube integrity imply strongly that they play key roles in cell wall-related processes. Furthermore, FERONIA acts as a cell surface regulator for RAC/ROP GTPases and activates production of reactive oxygen species which are, respectively, important molecular switches and mediators for diverse processes. These findings position the THESEUS 1/FERONIA family RLKs as surface regulators and potential cell wall sensors capable of broadly and profoundly impacting cellular pathways in response to diverse signals. Copyright © 2011 Elsevier Ltd. All rights reserved.

Regulation of cell-fate determination in Dictyostelium.

PubMed

Brown, J M; Firtel, R A

1999-12-15

A key step in the development of all multicellular organisms is the differentiation of specialized cell types. The eukaryotic microorganism Dictyostelium discoideum provides a unique experimental system for studying cell-type determination and spatial patterning in a developing multicellular organism. Unlike metazoans, which become multicellular by undergoing many rounds of cell division after fertilization of an egg, the social amoeba Dictyostelium achieves multicellularity by the aggregation of approximately 10(5) cells in response to nutrient depletion. Following aggregation, cell-type differentiation and morphogenesis result in a multicellular organism with only a few cell types that exhibit a defined patterning along the anterior-posterior axis of the organism. Analysis of the mechanisms that control these processes is facilitated by the relative simplicity of Dictyostelium development and the availability of molecular, genetic, and cell biological tools. Interestingly, analysis has shown that many molecules that play integral roles in the development of higher eukaryotes, such as PKA, STATs, and GSK-3, are also essential for cell-type differentiation and patterning in Dictyostelium. The role of these and other signaling pathways in the induction, maintenance, and patterning of cell types during Dictyostelium development is discussed.

Ubiquitin specific protease 2 acts as a key modulator for the regulation of cell cycle by adiponectin and leptin in cancer cells.

PubMed

Nepal, Saroj; Shrestha, Anup; Park, Pil-Hoon

2015-09-05

Adiponectin and leptin, both produced from adipose tissue, cause cell cycle arrest and progression, respectively in cancer cells. Ubiquitin specific protease-2 (USP-2), a deubiquitinating enzyme, is known to impair proteasome-induced degradation of cyclin D1, a critical cell cycle regulator. Herein, we investigated the effects of these adipokines on USP-2 expression and its potential role in the modulation of cell cycle. Treatment with globular adiponectin (gAcrp) decreased, whereas leptin increased USP-2 expression both in human hepatoma and breast cancer cells. In addition, overexpression or gene silencing of USP-2 affected cyclin D1 expression and cell cycle progression/arrest by adipokines. Adiponectin and leptin also modulated in vitro proteasomal activity, which was partially dependent on USP-2 expression. Taken together, our results reveal that modulation of USP-2 expression plays a crucial role in cell cycle regulation by adipokines. Thus, USP-2 would be a promising therapeutic target for the modulation of cancer cell growth by adipokines. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Lineage plasticity-mediated therapy resistance in prostate cancer.

PubMed

Blee, Alexandra M; Huang, Haojie

2018-06-12

Therapy resistance is a significant challenge for prostate cancer treatment in clinic. Although targeted therapies such as androgen deprivation and androgen receptor (AR) inhibition are effective initially, tumor cells eventually evade these strategies through multiple mechanisms. Lineage reprogramming in response to hormone therapy represents a key mechanism that is increasingly observed. The studies in this area have revealed specific combinations of alterations present in adenocarcinomas that provide cells with the ability to transdifferentiate and perpetuate AR-independent tumor growth after androgen-based therapies. Interestingly, several master regulators have been identified that drive plasticity, some of which also play key roles during development and differentiation of the cell lineages in the normal prostate. Thus, further study of each AR-independent tumor type and understanding underlying mechanisms are warranted to develop combinational therapies that combat lineage plasticity in prostate cancer.

Directional control of lamellipodia extension by constraining cell shape and orienting cell tractional forces

NASA Technical Reports Server (NTRS)

Parker, Kevin Kit; Brock, Amy Lepre; Brangwynne, Cliff; Mannix, Robert J.; Wang, Ning; Ostuni, Emanuele; Geisse, Nicholas A.; Adams, Josephine C.; Whitesides, George M.; Ingber, Donald E.

2002-01-01

Directed cell migration is critical for tissue morphogenesis and wound healing, but the mechanism of directional control is poorly understood. Here we show that the direction in which cells extend their leading edge can be controlled by constraining cell shape using micrometer-sized extracellular matrix (ECM) islands. When cultured on square ECM islands in the presence of motility factors, cells preferentially extended lamellipodia, filopodia, and microspikes from their corners. Square cells reoriented their stress fibers and focal adhesions so that tractional forces were concentrated in these corner regions. When cell tension was dissipated, lamellipodia extension ceased. Mechanical interactions between cells and ECM that modulate cytoskeletal tension may therefore play a key role in the control of directional cell motility.

Continued clearance of apoptotic cells critically depends on the phagocyte Ucp2 protein

PubMed Central

Park, Daeho; Han, Claudia; Elliott, Michael R.; Kinchen, Jason M.; Trampont, Paul C.; Das, Soumita; Collins, Sheila; Lysiak, Jeffrey J.; Hoehn, Kyle L.; Ravichandran, Kodi S.

2012-01-01

Rapid and efficient removal of apoptotic cells by phagocytes plays a key role during development, tissue homeostasis, and in controlling immune responses1–5. An important feature of efficient clearance is the capacity of a single phagocyte to ingest multiple apoptotic cells successively, and to process the increased load of corpse-derived cellular material6–9. However, factors that influence sustained phagocytic capacity or how they in turn influence continued clearance by phagocytes are not known. Here we identify that the ability of a phagocyte to control its mitochondrial membrane potential is a critical factor in the capacity of a phagocyte to engulf apoptotic cells. Changing the phagocyte mitochondrial membrane potential (genetically or pharmacologically) significantly affected phagocytosis, with lower potential enhancing engulfment and higher membrane potential inhibiting uptake. We then identified that Ucp2, a mitochondrial membrane protein that acts to lower the mitochondrial membrane potential10–12, is upregulated in phagocytes engulfing apoptotic cells (but not synthetic targets, bacteria, or yeast). Loss of Ucp2 limited the capacity of phagocytes to continually ingest apoptotic cells, while overexpression of Ucp2 increased the capacity for engulfment and the ability to engulf multiple apoptotic cells. Mutational and pharmacological inhibition of Ucp2 uncoupling activity reversed the positive effect of Ucp2 on engulfment capacity, suggesting a direct role for Ucp2-mediated mitochondrial function in phagocytosis. Macrophages from Ucp2-deficient mice13, 14 were impaired in their capacity to engulf apoptotic cells in vitro, and Ucp2-deficient mice displayed profound in vivo defects in clearing dying cells in the thymus and the testes. Collectively, these data suggest that phagocytes alter the mitochondrial membrane potential during engulfment to regulate uptake of sequential apoptotic cells, and that Ucp2 is a key molecular determinant of this step in vivo. Since Ucp2 function has also been linked to metabolic diseases and atherosclerosis14–16, these data identifying a new role for Ucp2 in regulating apoptotic cell clearance may provide additional insights toward understanding the complex etiology and pathogenesis of these diseases. PMID:21857682

Recent advances in our understanding of human host responses to tuberculosis

PubMed Central

Schluger, Neil W

2001-01-01

Tuberculosis remains one of the world's greatest public health challenges: 2 billion persons have latent infection, 8 million people develop active tuberculosis annually, and 2–3 million die. Recently, significant advances in our understanding of the human immune response against tuberculosis have occurred. The present review focuses on recent work in macrophage and T-cell biology that sheds light on the human immune response to tuberculosis. The role of key cytokines such as interferon-γ is discussed, as is the role of CD4+ and CD8+ T cells in immune regulation in tuberculosis, particularly with regard to implications for vaccine development and evaluation. PMID:11686880

Metabolic profiling reveals altered sugar and secondary metabolism in response to UGPase overexpression in Populus

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

Payyavula, Raja S.; Tschaplinski, Timothy J.; Jawdy, Sara

Background: UDP-glucose pyrophopharylase (UGPase) is a sugar metabolizing enzyme (E.C. 2.7.7.9) that catalyzes a reversible reaction of UDP-glucose and pyrophosphate from glucose-1-phosphate and uridine triphosphate glucose. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in woody plants such as Populus is poorly understood. Results: We characterized the functional role of UGPase in Populus deltoides by overexpressing a native gene. Overexpression of the native gene resulted in increased leaf area and leaf-to-shoot biomass ratio but decreased shoot and root growth. Metabolomic analyses showed that manipulation of UGPase results in perturbations inmore » primary as well as secondary metabolism resulting in reduced sugar and starch levels and increased phenolics such as caffeoyl- and feruloyl conjugates. While cellulose and lignin levels in the cell walls were not significantly altered, the syringyl-to-guaiacyl ratio was significantly reduced. Conclusions: These results demonstrate that UGPase plays a key role in the tightly coupled primary and secondary metabolic pathways and perturbation in its function results in pronounced effects on growth and metabolism outside of cell wall biosynthesis of Populus.« less

Metabolic profiling reveals altered sugar and secondary metabolism in response to UGPase overexpression in Populus

DOE PAGES

Payyavula, Raja S.; Tschaplinski, Timothy J.; Jawdy, Sara; ...

2014-10-07

Background: UDP-glucose pyrophopharylase (UGPase) is a sugar metabolizing enzyme (E.C. 2.7.7.9) that catalyzes a reversible reaction of UDP-glucose and pyrophosphate from glucose-1-phosphate and uridine triphosphate glucose. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in woody plants such as Populus is poorly understood. Results: We characterized the functional role of UGPase in Populus deltoides by overexpressing a native gene. Overexpression of the native gene resulted in increased leaf area and leaf-to-shoot biomass ratio but decreased shoot and root growth. Metabolomic analyses showed that manipulation of UGPase results in perturbations inmore » primary as well as secondary metabolism resulting in reduced sugar and starch levels and increased phenolics such as caffeoyl- and feruloyl conjugates. While cellulose and lignin levels in the cell walls were not significantly altered, the syringyl-to-guaiacyl ratio was significantly reduced. Conclusions: These results demonstrate that UGPase plays a key role in the tightly coupled primary and secondary metabolic pathways and perturbation in its function results in pronounced effects on growth and metabolism outside of cell wall biosynthesis of Populus.« less

Pleural mesothelial cells in pleural and lung diseases

PubMed Central

Antony, Veena B.

2015-01-01

During development, the mesoderm maintains a complex relationship with the developing endoderm giving rise to the mature lung. Pleural mesothelial cells (PMCs) derived from the mesoderm play a key role during the development of the lung. The pleural mesothelium differentiates to give rise to the endothelium and smooth muscle cells via epithelial-to-mesenchymal transition (EMT). An aberrant recapitulation of such developmental pathways can play an important role in the pathogenesis of disease processes such as idiopathic pulmonary fibrosis (IPF). The PMC is the central component of the immune responses of the pleura. When exposed to noxious stimuli, it demonstrates innate immune responses such as Toll-like receptor (TLR) recognition of pathogen associated molecular patterns as well as causes the release of several cytokines to activate adaptive immune responses. Development of pleural effusions occurs due to an imbalance in the dynamic interaction between junctional proteins, n-cadherin and β-catenin, and phosphorylation of adherens junctions between PMCs, which is caused in part by vascular endothelial growth factor (VEGF) released by PMCs. PMCs play an important role in defense mechanisms against bacterial and mycobacterial pleural infections, and in pathogenesis of malignant pleural effusion, asbestos related pleural disease and malignant pleural mesothelioma. PMCs also play a key role in the resolution of inflammation, which can occur with or without fibrosis. Fibrosis occurs as a result of disordered fibrin turnover and due to the effects of cytokines such as transforming growth factor-β, platelet-derived growth factor (PDGF), and basic fibroblast growth factor; which are released by PMCs. Recent studies have demonstrated a role for PMCs in the pathogenesis of IPF suggesting their potential as a cellular biomarker of disease activity and as a possible therapeutic target. Pleural-based therapies targeting PMCs for treatment of IPF and other lung diseases need further exploration. PMID:26150910

PINK1/Parkin-mediated mitophagy play a protective role in manganese induced apoptosis in SH-SY5Y cells.

PubMed

Zhang, Hong-Tao; Mi, Lan; Wang, Ting; Yuan, Lan; Li, Xue-Hui; Dong, Li-Sha; Zhao, Peng; Fu, Juan-Ling; Yao, Bi-Yun; Zhou, Zong-Can

2016-08-01

Manganese (Mn) as an environmental risk factor of Parkinson's disease (PD) is considered to cause manganism. Mitophagy is thought to play a key role in elimination the injured mitochondria. The goal of this paper was to explore whether the PINK1/Parkin-mediated mitophagy is activated and its role in Mn-induced mitochondrial dysfunction and cell death in SH-SY5Y cells. Here, we investigated effects of MnCl2 on ROS generation, mitochondrial membrane potential (MMP/ΔΨm) and apoptosis by FACS and examined PINK1/Parkin-mediated mitophagy by western-blotting and the co-localization of mitochondria and acidic lysosomes. Further, we explore the role of mitophagy in Mn-induced apoptosis by inhibition the mitophagy by knockdown Parkin level. Results show that MnCl2 dose-dependently caused ΔΨm decrease, ROS generation and apoptosis of dopaminergic SH-SY5Y cells. Moreover, Mn could induce mitophagy and PINK1/Parkin-mediated pathway was activated in SH-SY5Y cells. Transient transfection of Parkin siRNA knockdown the expressing level of parkin inhibited Mn-induced mitophagy and aggravated apoptosis of SH-SY5Y cells. In conclusion, our study demonstrated that Mn may induce PINK1/Parkin-mediated mitophagy, which may exert significant neuro-protective effect against Mn-induced dopaminergic neuronal cells apoptosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Role of Hemichannels in CNS Inflammation and the Inflammasome Pathway.

PubMed

Kim, Yeri; Davidson, Joanne O; Gunn, Katherine C; Phillips, Anthony R; Green, Colin R; Gunn, Alistair J

2016-01-01

Neurodegenerative, cardiovascular, and metabolic disorders, once triggered, share a number of common features, including sustained inflammatory cell activation and vascular disruption. These shared pathways are induced independently of any genetic predisposition to the disease or the precise external stimulus. Glial cells respond to injury with an innate immune response that includes release of proinflammatory cytokines and chemokines. Vascular endothelial cells may also be affected, leading to opening of the blood-brain barrier that facilitates invasion by circulating inflammatory cells. Inflammation can trigger acute neural injury followed by chronic inflammation that plays a key role in neurodegenerative conditions. Gap junction channels normally allow direct cell-to-cell communication. They are formed by the docking of two hemichannels, one contributed by each of the neighboring cells. While the opening probability of these channels is tightly controlled under resting conditions, hemichannels can open in response to injury or inflammatory factors, forming a large, relatively nonselective membrane pore. In this review, we consider the CNS immune system from the perspective that modulating connexin hemichannel opening can prevent tissue damage arising from excessive and uncontrolled inflammation. We discuss connexin channel roles in microglia, astrocytes, and endothelial cells in both acute and chronic inflammatory conditions, and in particular describe the role of connexin hemichannels in the inflammasome pathway where they contribute to both its activation and its spread to neighboring cells. Finally, we describe the benefits of hemichannel block in animal models of brain injury. © 2016 Elsevier Inc. All rights reserved.

Parkin New Cargos: a New ROS Independent Role for Parkin in Regulating Cell Division.

PubMed

Stieg, David C; Cooper, Katrina F

2016-01-01

Cell cycle progression requires the destruction of key cell cycle regulators by the multi-subunit E3 ligase called the anaphase promoting complex (APC/C). As the cell progresses through the cell cycle, the APC/C is sequentially activated by two highly conserved co-activators called Cdc20 and Cdh1. Importantly, APC/C Cdc20 is required to degrade substrates in G2/M whereas APC Cdh1 drives the cells into G1. Recently, Parkin, a monomeric E3 ligase that is required for ubiquitin-mediated mitophagy following mitochondrial stress, was shown to both bind and be activated by Cdc20 or Cdh1 during the cell cycle. This mitotic role for Parkin does not require an activating phosphorylation by its usual kinase partner PINK. Rather, mitotic Parkin activity requires phosphorylation on a different serine by the polo-like kinase Plk1. Interestingly, although Parkin Cdc20 and Parkin Cdh1 activity is independent of the APC/C, it mediates degradation of an overlapping subset of substrates. However, unlike the APC/C, Parkin is not necessary for cell cycle progression. Despite this, loss of Parkin activity accelerates genome instability and tumor growth in xenograft models. These findings provide a mechanism behind the previously described, but poorly understood, tumor suppressor role for Parkin. Taken together, studies suggest that the APC/C and Parkin have similar and unique roles to play in cell division, possibly being dependent upon the different subcellular address of these two ligases.

PKCalpha-mediated ERK, JNK and p38 activation regulates the myogenic program in human rhabdomyosarcoma cells.

PubMed

Mauro, Annunziata; Ciccarelli, Carmela; De Cesaris, Paola; Scoglio, Arianna; Bouché, Marina; Molinaro, Mario; Aquino, Angelo; Zani, Bianca Maria

2002-09-15

We have previously suggested that PKCalpha has a role in 12-O-Tetradecanoylphorbol-13-acetate (TPA)-mediated growth arrest and myogenic differentiation in human embryonal rhabdomyosarcoma cells (RD). Here, by monitoring the signalling pathways triggered by TPA, we demonstrate that PKCalpha mediates these effects by inducing transient activation of c-Jun N-terminal protein kinases (JNKs) and sustained activation of both p38 kinase and extracellular signal-regulated kinases (ERKs) (all referred to as MAPKs). Activation of MAPKs following ectopic expression of constitutively active PKCalpha, but not its dominant-negative form, is also demonstrated. We investigated the selective contribution of MAPKs to growth arrest and myogenic differentiation by monitoring the activation of MAPK pathways, as well as by dissecting MAPK pathways using MEK1/2 inhibitor (UO126), p38 inhibitor (SB203580) and JNK and p38 agonist (anisomycin) treatments. Growth-arresting signals are triggered either by transient and sustained JNK activation (by TPA and anisomycin, respectively) or by preventing both ERK and JNK activation (UO126) and are maintained, rather than induced, by p38. We therefore suggest a key role for JNK in controlling ERK-mediated mitogenic activity. Notably, sarcomeric myosin expression is induced by both TPA and UO126 but is abrogated by the p38 inhibitor. This finding indicates a pivotal role for p38 in controlling the myogenic program. Anisomycin persistently activates p38 and JNKs but prevents myosin expression induced by TPA. In accordance with this negative role, reactivation of JNKs by anisomycin, in UO126-pre-treated cells, also prevents myosin expression. This indicates that, unlike the transient JNK activation that occurs in the TPA-mediated myogenic process, long-lasting JNK activation supports the growth-arrest state but antagonises p38-mediated myosin expression. Lastly, our results with the MEK inhibitor suggest a key role of the ERK pathway in regulating myogenic-related morphology in differentiated RD cells.

BMP signaling in dermal papilla cells is required for their hair follicle-inductive properties

PubMed Central

Rendl, Michael; Polak, Lisa; Fuchs, Elaine

2008-01-01

Hair follicle (HF) formation is initiated when epithelial stem cells receive cues from specialized mesenchymal dermal papilla (DP) cells. In culture, DP cells lose their HF-inducing properties, but during hair growth in vivo, they reside within the HF bulb and instruct surrounding epithelial progenitors to orchestrate the complex hair differentiation program. To gain insights into the molecular program that maintains DP cell fate, we previously purified DP cells and four neighboring populations and defined their cell-type-specific molecular signatures. Here, we exploit this information to show that the bulb microenvironment is rich in bone morphogenetic proteins (BMPs) that act on DP cells to maintain key signature features in vitro and hair-inducing activity in vivo. By employing a novel in vitro/in vivo hybrid knockout assay, we ablate BMP receptor 1a in purified DP cells. When DPs cannot receive BMP signals, they lose signature characteristics in vitro and fail to generate HFs when engrafted with epithelial stem cells in vivo. These results reveal that BMP signaling, in addition to its key role in epithelial stem cell maintenance and progenitor cell differentiation, is essential for DP cell function, and suggest that it is a critical feature of the complex epithelial–mesenchymal cross-talk necessary to make hair. PMID:18281466

Collective dynamics of cell migration and cell rearrangements

NASA Astrophysics Data System (ADS)

Kabla, Alexandre

Understanding multicellular processes such as embryo development or cancer metastasis requires to decipher the contributions of local cell autonomous behaviours and long range interactions with the tissue environment. A key question in this context concerns the emergence of large scale coordination in cell behaviours, a requirement for collective cell migration or convergent extension. I will present a few examples where physical and mechanical aspects play a significant role in driving tissue scale dynamics.

Pivotal Role of Receptor-Interacting Protein Kinase 1 and Mixed Lineage Kinase Domain-Like in Neuronal Cell Death Induced by the Human Neuroinvasive Coronavirus OC43

PubMed Central

Meessen-Pinard, Mathieu; Le Coupanec, Alain

2016-01-01

ABSTRACT Human coronaviruses (HCoV) are respiratory pathogens with neuroinvasive, neurotropic, and neurovirulent properties, highlighting the importance of studying the potential implication of these viruses in neurological diseases. The OC43 strain (HCoV-OC43) was reported to induce neuronal cell death, which may participate in neuropathogenesis. Here, we show that HCoV-OC43 harboring two point mutations in the spike glycoprotein (rOC/Us183–241) was more neurovirulent than the wild-type HCoV-OC43 (rOC/ATCC) in mice and induced more cell death in murine and human neuronal cells. To evaluate the role of regulated cell death (RCD) in HCoV-OC43-mediated neural pathogenesis, we determined if knockdown of Bax, a key regulator of apoptosis, or RIP1, a key regulator of necroptosis, altered the percentage of neuronal cell death following HCoV-OC43 infection. We found that Bax-dependent apoptosis did not play a significant role in RCD following infection, as inhibition of Bax expression mediated by RNA interference did not confer cellular protection against the cell death process. On the other hand, we demonstrated that RIP1 and MLKL were involved in neuronal cell death, as RIP1 knockdown and chemical inhibition of MLKL significantly increased cell survival after infection. Taken together, these results indicate that RIP1 and MLKL contribute to necroptotic cell death after HCoV-OC43 infection to limit viral replication. However, this RCD could lead to neuronal loss in the mouse CNS and accentuate the neuroinflammation process, reflecting the severity of neuropathogenesis. IMPORTANCE Because they are naturally neuroinvasive and neurotropic, human coronaviruses are suspected to participate in the development of neurological diseases. Given that the strain OC43 is neurovirulent in mice and induces neuronal cell death, we explored the neuronal response to infection by characterizing the activation of RCD. Our results revealed that classical apoptosis associated with the Bax protein does not play a significant role in HCoV-OC43-induced neuronal cell death and that RIP1 and MLKL, two cellular proteins usually associated with necroptosis (an RCD back-up system when apoptosis is not adequately induced), both play a pivotal role in the process. As necroptosis disrupts cellular membranes and allows the release of damage-associated molecular patterns (DAMP) and possibly induces the production of proinflammatory cytokines, it may represent a proinflammatory cell death mechanism that contributes to excessive neuroinflammation and neurodegeneration and eventually to neurological disorders after a coronavirus infection. PMID:27795420

Phosphoinositide function in cytokinesis.

PubMed

Brill, Julie A; Wong, Raymond; Wilde, Andrew

2011-11-22

In systems as diverse as yeast, slime mold and animal cells, the levels and distribution of phosphatidylinositol phosphates (PIPs) must be strictly regulated for successful cell cleavage. The precise mechanism by which PIPs function in this process remains unknown. Recent experiments are beginning to shed light on the cellular pathways in which PIPs make key contributions during cytokinesis. In particular, PIPs promote proper actin cytoskeletal organization and direct membrane trafficking in dividing cells. Future research will uncover temporal and spatial regulation of the different PIPs, thus elucidating their role in cytoskeletal and membrane events that drive cell cleavage. Copyright © 2011 Elsevier Ltd. All rights reserved.

Experimental Proof for the Role of Nonlinear Photoionization in Plasmonic Phototherapy.

PubMed

Minai, Limor; Zeidan, Adel; Yeheskely-Hayon, Daniella; Yudovich, Shimon; Kviatkovsky, Inna; Yelin, Dvir

2016-07-13

Targeting individual cells within a heterogeneous tissue is a key challenge in cancer therapy, encouraging new approaches for cancer treatment that complement the shortcomings of conventional therapies. The highly localized interactions triggered by focused laser beams promise great potential for targeting single cells or small cell clusters; however, most laser-tissue interactions often involve macroscopic processes that may harm healthy nearby tissue and reduce specificity. Specific targeting of living cells using femtosecond pulses and nanoparticles has been demonstrated promising for various potential therapeutic applications including drug delivery via optoporation, drug release, and selective cell death. Here, using an intense resonant femtosecond pulse and cell-specific gold nanorods, we show that at certain irradiation parameters cell death is triggered by nonlinear plasmonic photoionization and not by thermally driven processes. The experimental results are supported by a physical model for the pulse-particle-medium interactions. A good correlation is found between the calculated total number and energy of the generated free electrons and the observed cell death, suggesting that femtosecond photoionization plays the dominant role in cell death.

Are nestin-positive mesenchymal stromal cells a better source of cells for CNS repair?

PubMed

Lindsay, Susan L; Barnett, Susan C

2017-06-01

In recent years there has been a great deal of research within the stem cell field which has led to the definition and classification of a range of stem cells from a plethora of tissues and organs. Stem cells, by classification, are considered to be pluri- or multipotent and have both self-renewal and multi-differentiation capabilities. Presently there is a great deal of interest in stem cells isolated from both embryonic and adult tissues in the hope they hold the therapeutic key to restoring or treating damaged cells in a number of central nervous system (CNS) disorders. In this review we will discuss the role of mesenchymal stromal cells (MSCs) isolated from human olfactory mucosa, with particular emphasis on their potential role as a candidate for transplant mediated repair in the CNS. Since nestin expression defines the entire population of olfactory mucosal derived MSCs, we will compare these cells to a population of neural crest derived nestin positive population of bone marrow-MSCs. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Role of Paracrine and Autocrine Signaling in the Early Phase of Adipogenic Differentiation of Adipose-derived Stem Cells

PubMed Central

Hemmingsen, Mette; Vedel, Søren; Skafte-Pedersen, Peder; Sabourin, David; Collas, Philippe; Bruus, Henrik; Dufva, Martin

2013-01-01

Introduction High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways. Methods and results Adipogenic differentiation of human adipose-derived stem cells (ASCs) cultured in a microfluidic system was investigated under perfusion conditions with an adipogenic medium or an adipogenic medium supplemented with supernatant from differentiating ASCs (conditioned medium). Conditioned medium increased adipogenic differentiation compared to adipogenic medium with respect to accumulation of lipid-filled vacuoles and gene expression of key adipogenic markers (C/EBPα, C/EBPβ, C/EBPδ, PPARγ, LPL and adiponectin). The positive effects of conditioned medium were observed early in the differentiation process. Conclusions Using different cell densities and microfluidic perfusion cell cultures to suppress the effects of cell-released factors, we have demonstrated the significant role played by auto- or paracrine signaling in adipocyte differentiation. The cell-released factor(s) were shown to act in the recruitment phase of the differentiation process. PMID:23723991

DISTAG/TBCCd1 Is Required for Basal Cell Fate Determination in Ectocarpus[OPEN

PubMed Central

Godfroy, Olivier; Uji, Toshiki; Nagasato, Chikako; Colin, Sebastien; Mignerot, Laure; Motomura, Taizo

2017-01-01

Brown algae are one of the most developmentally complex groups within the eukaryotes. As in many land plants and animals, their main body axis is established early in development, when the initial cell gives rise to two daughter cells that have apical and basal identities, equivalent to shoot and root identities in land plants, respectively. We show here that mutations in the Ectocarpus DISTAG (DIS) gene lead to loss of basal structures during both the gametophyte and the sporophyte generations. Several abnormalities were observed in the germinating initial cell in dis mutants, including increased cell size, disorganization of the Golgi apparatus, disruption of the microtubule network, and aberrant positioning of the nucleus. DIS encodes a TBCCd1 protein, which has a role in internal cell organization in animals, Chlamydomonas reinhardtii, and trypanosomes. Our study highlights the key role of subcellular events within the germinating initial cell in the determination of apical/basal cell identities in a brown alga and emphasizes the remarkable functional conservation of TBCCd1 in regulating internal cell organization across extremely distant eukaryotic groups. PMID:29208703

Autophagy triggered by magnolol derivative negatively regulates angiogenesis

PubMed Central

Kumar, S; Guru, S K; Pathania, A S; Kumar, A; Bhushan, S; Malik, F

2013-01-01

Angiogenesis has a key role in the tumor progression and metastasis; targeting endothelial cell proliferation has emerged as a promising therapeutic strategy for the prevention of cancer. Previous studies have revealed a complex association between the process of angiogenesis and autophagy and its outcome on tumorigenesis. Autophagy, also known as type-II cell death, has been identified as an alternative way of cell killing in apoptotic-resistant cancer cells. However, its involvement in chemoresistance and tumor promotion is also well known. In this study, we used a derivate of natural product magnolol (Ery5), a potent autophagy inducer, to study the association between the autophagy and angiogenesis in both in vitro and in vivo model system. We found that the robust autophagy triggered by Ery5, inhibited angiogenesis and caused cell death independent of the apoptosis in human umbilical cord vein endothelial cells and PC-3 cells. Ery5 induced autophagy effectively inhibited cell proliferation, migration, invasion and tube formation. We further demonstrated that Ery5-mediated autophagy and subsequent inhibition of angiogenesis was reversed when autophagy was inhibited through 3-methyl adenine and knocking down of key autophagy proteins ATG7 and microtubule-associated protein light chain 3. While evaluating the negative regulation of autophagy on angiogenesis, it was interesting to find that angiogenic environment produced by the treatment of VEGF and CoCl2 remarkably downregulated the autophagy and autophagic cell death induced by Ery5. These studies, while disclosing the vital role of autophagy in the regulation of angiogenesis, also suggest that the potent modulators of autophagy can lead to the development of effective therapeutics in apoptosis-resistant cancer. PMID:24176847

Simulated-microgravity induced G2/M arrest in zebrafish embryonic cell is regulated by dre-miR-22a and its target cep135

NASA Astrophysics Data System (ADS)

Hang, Xiaoming; Sun, Yeqing; Wu, Di; Li, Yixiao; Wang, Ruonan

2016-07-01

Microgravity has been recognized as a major environmental factor that can induce a number of adverse effects such as bone loss, skeletal muscle atrophy, cardiovascular problems and immune system dysregulation, etc. The underlying mechanisms are not absolutely identified yet. Our previous study demonstrated centrosomal protein of 135 kDa (CEP135) might be a microgravity sensitive molecule. In this study, the expression and regulation of CEP135 and its possible roles in cell cycle regulation under simulated microgravity (SMG) condition were investigated. SMG can induce significant increasing of cep135 in zebrafish embryos, detected by both in situ hybridization and RT-qPCR, while CEP135 protein level was significantly decreased, tested by western blot. The similar results were also obtained in zebrafish embryonic cells (ZF4) exposed to SMG. Accordingly, the expression level of dre-miR-22a, which might be the potential miRNA for targeting cep135, was significantly increased in SMG exposed ZF4 cells. By combining the results obtained from transfection and dual luciferase reporter assay, we firstly confirmed that dre-miR-22a regulated the expression of cep135 in ZF4 cells. Further investigation on cell cycle demonstrated SMG induced a significant arrest in G2/M phase. Transfection of dre-miR-22a also induced G2/M arrest in ZF4 cells. These results suggest that SMG induced G2/M arrest in ZF4 cells is via cep135, while dre-miR-22a plays a key role in modulating this effect. Key Words: Simulated-microgravity; cep135; dre-miR-22a; G2/M arrest; zebrafish embryonic cell

PD-1 suppresses development of humoral responses that protect against Tn-bearing tumors

PubMed Central

Haro, Marcela A.; Littrell, Chad A.; Yin, Zhaojun; Huang, Xuefei; Haas, Karen M.

2017-01-01

Tn is a carbohydrate antigen uniquely exposed on tumor mucins and thus, an ideal target for immunotherapy. However, it has been difficult to elicit protective antibody responses against Tn antigen and other tumor associated carbohydrate antigens. Our study demonstrates this can be attributed to PD-1 immuno-inhibition. Our data show a major role for PD-1 in suppressing mucin- and Tn-specific B-cell activation, expansion, and antibody production important for protection against Tn-bearing tumor cells. These Tn/mucin-specific B cells belong to the innate-like B-1b cell subset typically responsible for T cell–independent antibody responses. Interestingly, PD-1–mediated regulation is B cell–intrinsic and CD4+ cells play a key role in supporting Tn/mucin-specific B cell antibody production in the context of PD-1 deficiency. Mucin-reactive antibodies produced in the absence of PD-1 inhibition largely belong to the IgM subclass and elicit potent antitumor effects via a complement-dependent mechanism. The identification of this role for PD-1 in regulating B cell–dependent antitumor immunity to Tn antigen highlights an opportunity to develop new therapeutic strategies targeting tumor associated carbohydrate antigens. PMID:27856425

GLABROUS INFLORESCENCE STEMS regulates trichome branching by genetically interacting with SIM in Arabidopsis.

PubMed

Sun, Li-Li; Zhou, Zhong-Jing; An, Li-Jun; An, Yan; Zhao, Yong-Qin; Meng, Xiao-Fang; Steele-King, Clare; Gan, Yin-Bo

2013-07-01

Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first morphological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.

Chemokines and skin diseases.

PubMed

Sugaya, Makoto

2015-04-01

Chemokines are small molecules that induce chemotaxis and activation of certain subsets of leukocytes. The expression patterns of chemokines and chemokine receptors are specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases. CCL17 expressed by Langerhans cells, blood endothelial cells, and fibroblasts plays a key role in attracting Th2 cells and tumor cells of adult T-cell leukemia/lymphoma and mycosis fungoides/Sézary syndrome into the skin, developing various Th2-type inflammatory skin diseases as well as cutaneous lymphoma. CCL11 and CCL26 expressed by skin-resident cells, such as fibroblasts, blood endothelial cells, and keratinocytes, induce infiltration of CCR3-expressing cells such as Th2 cells and eosinophils. CCL11 may also serve as an autocrine as well as a paracrine in anaplastic large cell lymphoma. CX3CL1 expressed on blood endothelial cells leads to infiltration of CX3CR1(+) immune cells, such as mast cells, neutrophils, and macrophages, playing important roles in wound healing, tumor immunity, and vasculitis. Biologics targeting chemokines and their receptors are promising strategies for various skin diseases that are resistant to the current therapy.

Role of natural killer cells in lung cancer.

PubMed

Aktaş, Ozge Nur; Öztürk, Ayşe Bilge; Erman, Baran; Erus, Suat; Tanju, Serhan; Dilege, Şükrü

2018-06-01

One of the key immune cells involved in the pathogenesis of lung cancer is natural killer (NK) cells and these cells are novel targets for therapeutic applications in lung cancer. The purpose of this review is to summarize the current literature on lung cancer pathogenesis with a focus on the interaction between NK cells and smoking, how these factors are related to the pathogenesis of lung cancer and how NK cell-based immunotherapy effect lung cancer survival. The relevant literature from PubMed and Medline databases is reviewed in this article. The cytolytic potential of NK cells are reduced in lung cancer and increasing evidence suggests that improving NK cell functioning may induce tumor regression. Recent clinical trials on NK cell-based novel therapies such as cytokines including interleukin (IL)-15, IL-12 and IL-2, NK-92 cell lines and allogenic NK cell immunotherapy showed promising results with less adverse effects on the lung cancer survival. The NK cell targeting strategy has not yet been approved for lung cancer treatment. More clinical studies focusing on the role of NK cells in lung cancer pathogenesis are warranted to develop novel NK cell-based therapeutic approaches for the treatment of lung cancer.

G protein-coupled receptor kinase 2 positively regulates epithelial cell migration

PubMed Central

Penela, Petronila; Ribas, Catalina; Aymerich, Ivette; Eijkelkamp, Niels; Barreiro, Olga; Heijnen, Cobi J; Kavelaars, Annemieke; Sánchez-Madrid, Francisco; Mayor, Federico

2008-01-01

Cell migration requires integration of signals arising from both the extracellular matrix and messengers acting through G protein-coupled receptors (GPCRs). We find that increased levels of G protein-coupled receptor kinase 2 (GRK2), a key player in GPCR regulation, potentiate migration of epithelial cells towards fibronectin, whereas such process is decreased in embryonic fibroblasts from hemizygous GRK2 mice or upon knockdown of GRK2 expression. Interestingly, the GRK2 effect on fibronectin-mediated cell migration involves the paracrine/autocrine activation of a sphingosine-1-phosphate (S1P) Gi-coupled GPCR. GRK2 positively modulates the activity of the Rac/PAK/MEK/ERK pathway in response to adhesion and S1P by a mechanism involving the phosphorylation-dependent, dynamic interaction of GRK2 with GIT1, a key scaffolding protein in cell migration processes. Furthermore, decreased GRK2 levels in hemizygous mice result in delayed wound healing rate in vivo, consistent with a physiological role of GRK2 as a regulator of coordinated integrin and GPCR-directed epithelial cell migration. PMID:18369319

Fuel cell commercialization: The key to a hydrogen economy

NASA Astrophysics Data System (ADS)

Zegers, P.

With the current level of global oil production, oil reserves will be sufficient for 40 years. However, due to the fact that the global GDP will have increased by a factor seven in 2050, oil reserves are likely to be exhausted in a much shorter time period. The EU and car industry aim at a reduction of the consumption of oil, at energy savings (with a key role for fuel cells) and an increased use of hydrogen from natural gas and, possibly, coal, in the medium term. The discovery of huge methane resources as methane hydrates (20 times those of oil, gas and coal together) in oceans at 1000-3000 m depth could be of major importance. In the long term, the EU aims at a renewable energy-based energy supply. The European Hydrogen and Fuel Cell Technology Platform is expected to play a major role in bringing about a hydrogen economy. The availability of commercial fuel cells is here a prerequisite. However, after many years of research, fuel cells have not yet been commercialized. If they will not succeed to enter the market within 5 years there is a real danger that activities aiming at a hydrogen society will peter out. In a hydrogen strategy, high priority should therefore be given to actions which will bring about fuel cell commercialization within 5 years. They should include the identification of fuel cell types and (niche) markets which are most favorable for a rapid market introduction. These actions should include focused short-term RTD aiming at cost reduction and increased reliability.

A Counterregulatory Mechanism Impacting Androgen Suppression Therapy

DTIC Science & Technology

2016-03-01

lay audience can understand (Scientific American style). Testosterone, a steroid hormone , plays a key role in the development, growth , and...Sry, Sox9, Dmrt1) (20, 57–60), FSH signaling (Fshr) (61, 62), cell-cell interactions (Clmp, Cldn11, Cx30.2) (19, 38, 63), and peptide hormone ...including genes associated with sex determination (Sry, Sox9, and Dmrt1) (13–17), peptide hormone production (Inha, Inhba, and Amh) (18), gonadotropin

Multigenerational Breast Cancer Risk Factors in African-American Women

DTIC Science & Technology

1996-10-01

Estrogen is of special interest in breast cancer etiology. It’s role in breast cell multiplication, the total number of menstrual cycles and possible...genetic alterations in cells during this replication are thought to be important in disease development. The typical woman is thought to have...as a key source to collect information. Introduction activities, such as the use of tobacco and alcohol; and have less access to health care services

Rapid Translation of a Novel and Potent Vaccine in HER2+ Metastatic Breast Cancer Patients

DTIC Science & Technology

2013-10-01

Figure 1A). Instead, phosphorylation of Akt threonine 308 remained intact, implicating a role for PDK1-the kinase responsible for phosphorylating AktT308...including key regulators in signal transduction and cell cycle con- trol, steroid hormone receptors, and tyrosine and serine/ threonine kinases [7-9...xenograft experiments, cells were injected s.c. into the flank of nonobese diabetic severe combined immunodeficient (NOD/SCID) mice (at indicated

Challenges for fuel cells as stationary power resource in the evolving energy enterprise

NASA Astrophysics Data System (ADS)

Rastler, Dan

The primary market challenges for fuel cells as stationary power resources in evolving energy markets are reviewed. Fuel cell power systems have significant barriers to overcome in their anticipated role as decentralized energy power systems. Market segments for fuel cells include combined heat and power; low-cost energy, premium power; peak shaving; and load management and grid support. Understanding the role and fit of fuel cell systems in evolving energy markets and the highest value applications are a major challenge for developers and government funding organizations. The most likely adopters of fuel cell systems and the challenges facing each adopter in the target market segment are reviewed. Adopters include generation companies, utility distribution companies, retail energy service providers and end-users. Key challenges include: overcoming technology risk; achieving retail competitiveness; understanding high value markets and end-user needs; distribution and service channels; regulatory policy issues; and the integration of these decentralized resources within the electrical distribution system.

Small organelle, big responsibility: the role of centrosomes in development and disease

PubMed Central

Chavali, Pavithra L.; Pütz, Monika; Gergely, Fanni

2014-01-01

The centrosome, a key microtubule organizing centre, is composed of centrioles, embedded in a protein-rich matrix. Centrosomes control the internal spatial organization of somatic cells, and as such contribute to cell division, cell polarity and migration. Upon exiting the cell cycle, most cell types in the human body convert their centrioles into basal bodies, which drive the assembly of primary cilia, involved in sensing and signal transduction at the cell surface. Centrosomal genes are targeted by mutations in numerous human developmental disorders, ranging from diseases exclusively affecting brain development, through global growth failure syndromes to diverse pathologies associated with ciliary malfunction. Despite our much-improved understanding of centrosome function in cellular processes, we know remarkably little of its role in the organismal context, especially in mammals. In this review, we examine how centrosome dysfunction impacts on complex physiological processes and speculate on the challenges we face when applying knowledge generated from in vitro and in vivo model systems to human development. PMID:25047622

Tuning cancer fate: the unremitting role of host immunity

PubMed Central

Molon, B.; Viola, A.

2017-01-01

Host immunity plays a central and complex role in dictating tumour progression. Solid tumours are commonly infiltrated by a large number of immune cells that dynamically interact with the surrounding microenvironment. At first, innate and adaptive immune cells successfully cooperate to eradicate microcolonies of transformed cells. Concomitantly, surviving tumour clones start to proliferate and harness immune responses by specifically hijacking anti-tumour effector mechanisms and fostering the accumulation of immunosuppressive immune cell subsets at the tumour site. This pliable interplay between immune and malignant cells is a relentless process that has been concisely organized in three different phases: elimination, equilibrium and escape. In this review, we aim to depict the distinct immune cell subsets and immune-mediated responses characterizing the tumour landscape throughout the three interconnected phases. Importantly, the identification of key immune players and molecules involved in the dynamic crosstalk between tumour and immune system has been crucial for the introduction of reliable prognostic factors and effective therapeutic protocols against cancers. PMID:28404796

SATB1 plays an oncogenic role in esophageal cancer by up-regulation of FN1 and PDGFRB.

PubMed

Song, Guiqin; Liu, Kang; Yang, Xiaolin; Mu, Bo; Yang, Junbao; He, Lang; Hu, Xin; Li, Qiujiang; Zhao, Yunxia; Cai, Xiaoming; Feng, Gang

2017-03-14

Esophageal cancer is a highly aggressive malignancy with very poor overall prognosis. Given the strong clinical relevance of SATB1 in esophagus cancer and other cancers suggested by previous studies, the exact function of SATB1 in esophagus cancer development is still unknown. Here we showed that the knockdown of SATB1 in esophageal cancer cell lines diminished the cell proliferation, survival and invasion. Whole genome transcriptome analysis of SATB1 knockdown cells revealed the different gene expression profiles between TE-1 cells and MDA-MB-231 cells. Network analysis and functional experiments further identified FN1 and PDGFRB to be key downstream genes regulated by SATB1 in esophageal cancer cells. Importantly, FN1 and PDGFRB were found to be highly expressed in human esophageal cancer. In summary, we provided the first molecular evidence that SATB1 played an oncogenic role in esophageal cancer by up-regulation of FN1 and PDGFRB.

Clearance of Apoptotic Cells by Tissue Epithelia: A Putative Role for Hepatocytes in Liver Efferocytosis

PubMed Central

Davies, Scott P.; Reynolds, Gary M.; Stamataki, Zania

2018-01-01

Toxic substances and microbial or food-derived antigens continuously challenge the liver, which is tasked with their safe neutralization. This vital organ is also important for the removal of apoptotic immune cells during inflammation and has been previously described as a “graveyard” for dying lymphocytes. The clearance of apoptotic and necrotic cells is known as efferocytosis and is a critical liver function to maintain tissue homeostasis. Much of the research into this form of immunological control has focused on Kupffer cells, the liver-resident macrophages. However, hepatocytes (and other liver resident cells) are competent efferocytes and comprise 80% of the liver mass. Little is known regarding the mechanisms of apoptotic and necrotic cell capture by epithelia, which lack key receptors that mediate phagocytosis in macrophages. Herein, we discuss recent developments that increased our understanding of efferocytosis in tissues, with a special focus on the liver parenchyma. We discuss the impact of efferocytosis in health and in inflammation, highlighting the role of phagocytic epithelia. PMID:29422896

Effector and memory CD8+ T cell differentiation: toward a molecular understanding of fate determination.

PubMed

Belz, Gabrielle T; Kallies, Axel

2010-06-01

CD8(+) T cells play a key role in protecting the body against invading microorganisms. Their capacity to control infection relies on the development of peripheral effector and memory T cells. Much of our current knowledge has been gained by tracking alterations of the phenotype of CD8(+) T cells but the molecular understanding of the events that underpin the emergence of heterogeneous effector and memory CD8(+) T cells in response to infection has remained limited. This review focuses on the recent progress in our understanding of the molecular wiring of this differentiation process. Copyright 2010 Elsevier Ltd. All rights reserved.

A molecular imaging analysis of C×43 association with Cdo during skeletal myoblast differentiation

NASA Astrophysics Data System (ADS)

Nosi, Daniele; Mercatelli, Raffaella; Chellini, Flaminia; Soria, Silvia; Pini, Alessandro; Formigli, Lucia; Quercioli, Franco

2014-02-01

Cell-to-cell contacts are crucial for cell differentiation. The promyogenic cell surface protein, Cdo, functions as a component of multiprotein clusters to mediate cell adhesion signaling. Connexin43, the main connexin forming gap junctions, also plays a key role in myogenesis. At least part of its effects are independent of the intercellular channel function, but the mechanisms underlying are unknown. Here, using multiple optical approaches, we provided the first evidence that Cx43 physically interacts with Cdo to form dynamic complexes during myoblast differentiation, offering clues for considering this interaction a structural basis of the channel-independent function of Cx43.

Mechanical Regulation in Cell Division and in Neurotransmitter Release

NASA Astrophysics Data System (ADS)

Thiyagarajan, Sathish

During their lifecycle, cells must produce forces which play important roles in several subcellular processes. Force-producing components are organized into macromolecular assemblies of proteins that are often dynamic, and are constructed or disassembled in response to various signals. The forces themselves may directly be involved in subcellular mechanics, or they may influence mechanosensing proteins either within or outside these structures. These proteins play different roles: they may ensure the stability of the force-producing structure, or they may send signals to a coupled process. The generation and sensing of subcellular forces is an active research topic, and this thesis focusses on the roles of these forces in two key areas: cell division and neurotransmitter release. The first part of the thesis deals with the effect of force on cell wall growth regulation during division in the fission yeast Schizosaccharomyces pombe, a cigar-shaped, unicellular organism. During cytokinesis, the last stage of cell division in which the cell physically divides into two, a tense cytokinetic ring anchored to the cellular membrane assembles and constricts, accompanied by the inward centripetal growth of new cell wall, called septum, in the wake of the inward-moving membrane. The contour of the septum hole maintains its circularity as it reduces in size--an indication of regulated growth. To characterize the cell wall growth process, we performed image analysis on contours of the leading edge of the septum obtained via fluorescence microscopy in the labs of our collaborators. We quantified the deviations from circularity using the edge roughness. The roughness was spatially correlated, suggestive of regulated growth. We hypothesized that the cell wall growers are mechanosensitive and respond to the force exerted by the ring. A mathematical model based on this hypothesis then showed that this leads to corrections of roughness in a curvature-dependent fashion. Thus, one of the roles of ring tension is to communicate with the mechanosensitive septum growth processes and coordinate growth to ensure the daughter cells have a functional cell wall. The second part of the thesis deals with how ring tension is produced and sustained, using experimentally measured ultrastructure of the cytokinetic ring itself. Recent super-resolution experiments have revealed that several key proteins of the fission yeast constricting ring are organized into membrane-anchored complexes called nodes. The force producing protein myosin-II in these nodes exerts pulling forces on polymeric actin filaments that are synthesized from polymerizers residing in the nodes. How these forces are marshalled to generate ring tension, and how such an organization maintains its stability is unclear. Using a mathematical model with coarse-grained representations of actin and myosin, we showed that such a node-based organization reproduces previously measured ring tension values. The model explains the origin of experimentally observed bidirectional motion of the nodes in the ring, and showed that turnover of the nodes rescues the ring from inherent contractile instabilities that would be expected when a force-producing structure is made up of small object that effectively attract one another. Finally, the third part of the thesis deals with the role of forces produced by SNARE proteins at synapses between two neurons during neurotransmission. A key step here is synaptic release, where inside a neuron, membrane-bound compartments called vesicles filled with neurotransmitter fuse with the membrane of the neuron forming a transient fusion pore, and release their contents to the outside of the cell. These neurotransmitter molecules are sensed by another neuron that is physically separate from the neuron in question and this neuron propagates the signal henceforth. Thus, regulation of neurotransmitter release is a key step in neurotransmission. A fusion machinery consisting of several proteins facilitates membrane fusion, and pore nucleation requires the formation of a SNARE protein complex in this machinery, whose role during pore dilation is unclear. Using electrophysiological measurements, our collaborators experimentally measured the statistics of the size of single fusion pores in vitro, and observed that average pore sizes increased with the number of SNARE proteins. Using mathematical modeling, we showed that this effect was due to an entropic crowding force that expands the pore and increases with the number of SNAREs, and counteracts the energy barrier to fusion pore expansion.

Protein Kinase C-Related Kinase (PKN/PRK). Potential Key-Role for PKN1 in Protection of Hypoxic Neurons.

PubMed

Thauerer, Bettina; Zur Nedden, Stephanie; Baier-Bitterlich, Gabriele

2014-05-01

Serine/threonine protein kinase C-related kinase (PKN/PRK) is a family of three isoenzymes (PKN1, PKN2, PKN3), which are widely distributed in eukaryotic organisms and share the same overall domain structure. The Nterminal region encompasses a conserved repeated domain, termed HR1a-c as well as a HR2/C2 domain. The serine/threonine kinase domain is found in the C-terminal region of the protein and shows high sequence homology to other members of the PKC superfamily. In neurons, PKN1 is the most abundant isoform and has been implicated in a variety of functions including cytoskeletal organization and neuronal differentiation and its deregulation may contribute to neuropathological processes such as amyotrophic lateral sclerosis and Alzheimer's disease. We have recently identified a candidate role of PKN1 in the regulation of neuroprotective processes during hypoxic stress. Our key findings were that: 1) the activity of PKN1 was significantly increased by hypoxia (1% O2) and neurotrophins (nerve growth factor and purine nucleosides); 2) Neuronal cells, deficient of PKN1 showed a decrease of cell viability and neurite formation along with a disturbance of the F-actinassociated cytoskeleton; 3) Purine nucleoside-mediated neuroprotection during hypoxia was severely hampered in PKN1 deficient neuronal cells, altogether suggesting a potentially critical role of PKN1 in neuroprotective processes. This review gives an up-to-date overview of the PKN family with a special focus on the neuroprotective role of PKN1 in hypoxia.

Branches of the NF-κB signaling pathway regulate proliferation of oval cells in rat liver regeneration.

PubMed

Zhao, W M; Qin, Y L; Niu, Z P; Chang, C F; Yang, J; Li, M H; Zhou, Y; Xu, C S

2016-03-24

The NF-kB (nuclear factor kB) pathway is involved in the proliferation of many cell types. To explore the mechanism of the NF-kB signaling pathway underlying the oval cell proliferation during rat liver regeneration, the Rat Genome 230 2.0 Array was used to detect expression changes of NF-kB signaling pathway-related genes in oval cells. The results revealed that the expression levels of many genes in the NF-kB pathway were significantly changed. This included 48 known genes and 16 homologous genes, as well as 370 genes and 85 homologous genes related to cell proliferation. To further understand the biological significance of these changes, an expression profile function was used to analyze the potential biological processes. The results showed that the NF-kB pathway promoted oval cell proliferation mainly through three signaling branches; the tumor necrosis factor alpha branch (TNF-a pathway), the growth factor branch, and the chemokine branch. An integrated statistics method was used to define the key genes in the NF-kB pathway. Seven genes were identified to play vital roles in the NF-kB pathway. To confirm these results, the protein content, including two key genes (TNF and FGF11) and two non-key genes (CCL2 and TNFRSF12A), were analyzed using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry. The results were generally consistent with those of the array data. To conclude, three branches and seven key genes were involved in the NF-kB signaling pathway that regulates oval cell proliferation during rat liver regeneration.

MAPK1 is required for establishing the pattern of cell proliferation and for cell survival during lens development

PubMed Central

Upadhya, Dinesh; Ogata, Masato; Reneker, Lixing W.

2013-01-01

The mitogen-activated protein kinases (MAPKs; also known as ERKs) are key intracellular signaling molecules that are ubiquitously expressed in tissues and were assumed to be functionally equivalent. Here, we use the mouse lens as a model system to investigate whether MAPK1 plays a specific role during development. MAPK3 is known to be dispensable for lens development. We demonstrate that, although MAPK1 is uniformly expressed in the lens epithelium, its deletion significantly reduces cell proliferation in the peripheral region, an area referred to as the lens germinative zone in which most active cell division occurs during normal lens development. By contrast, cell proliferation in the central region is minimally affected by MAPK1 deletion. Cell cycle regulators, including cyclin D1 and survivin, are downregulated in the germinative zone of the MAPK1-deficient lens. Interestingly, loss of MAPK1 subsequently induces upregulation of phosphorylated MAPK3 (pMAPK3) levels in the lens epithelium; however, this increase in pMAPK3 is not sufficient to restore cell proliferation in the germinative zone. Additionally, MAPK1 plays an essential role in epithelial cell survival but is dispensable for fiber cell differentiation during lens development. Our data indicate that MAPK1/3 control cell proliferation in the lens epithelium in a spatially defined manner; MAPK1 plays a unique role in establishing the highly mitotic zone in the peripheral region, whereas the two MAPKs share a redundant role in controlling cell proliferation in the central region of the lens epithelium. PMID:23482492

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

Qian, Qinyi; Zhou, Hao; Chen, Yan

Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to addressmore » this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.« less

Akt signaling is critical for memory CD8+ T-cell development and tumor immune surveillance.

PubMed

Rogel, Anne; Willoughby, Jane E; Buchan, Sarah L; Leonard, Henry J; Thirdborough, Stephen M; Al-Shamkhani, Aymen

2017-02-14

Memory CD8 + T cells confer long-term immunity against tumors, and anticancer vaccines therefore should maximize their generation. Multiple memory CD8 + T-cell subsets with distinct functional and homing characteristics exist, but the signaling pathways that regulate their development are ill defined. Here we examined the role of the serine/threonine kinase Akt in the generation of protective immunity by CD8 + T cells. Akt is known to be activated by the T-cell antigen receptor and the cytokine IL-2, but its role in T-cell immunity in vivo has not been explored. Using CD8 + T cells from pdk1 K465E/K465E knockin mice, we found that decreased Akt activity inhibited the survival of T cells during the effector-to-memory cell transition and abolished their differentiation into C-X-C chemokine receptor 3 (CXCR3) lo CD43 lo effector-like memory cells. Consequently, antitumor immunity by CD8 + T cells that display defective Akt signaling was substantially diminished during the memory phase. Reduced memory T-cell survival and altered memory cell differentiation were associated with up-regulation of the proapoptotic protein Bim and the T-box transcription factor eomesodermin, respectively. These findings suggest an important role for effector-like memory CD8 + T cells in tumor immune surveillance and identify Akt as a key signaling node in the development of protective memory CD8 + T-cell responses.

Akt signaling is critical for memory CD8+ T-cell development and tumor immune surveillance

PubMed Central

Rogel, Anne; Willoughby, Jane E.; Buchan, Sarah L.; Leonard, Henry J.; Thirdborough, Stephen M.; Al-Shamkhani, Aymen

2017-01-01

Memory CD8+ T cells confer long-term immunity against tumors, and anticancer vaccines therefore should maximize their generation. Multiple memory CD8+ T-cell subsets with distinct functional and homing characteristics exist, but the signaling pathways that regulate their development are ill defined. Here we examined the role of the serine/threonine kinase Akt in the generation of protective immunity by CD8+ T cells. Akt is known to be activated by the T-cell antigen receptor and the cytokine IL-2, but its role in T-cell immunity in vivo has not been explored. Using CD8+ T cells from pdk1K465E/K465E knockin mice, we found that decreased Akt activity inhibited the survival of T cells during the effector-to-memory cell transition and abolished their differentiation into C-X-C chemokine receptor 3 (CXCR3)loCD43lo effector-like memory cells. Consequently, antitumor immunity by CD8+ T cells that display defective Akt signaling was substantially diminished during the memory phase. Reduced memory T-cell survival and altered memory cell differentiation were associated with up-regulation of the proapoptotic protein Bim and the T-box transcription factor eomesodermin, respectively. These findings suggest an important role for effector-like memory CD8+ T cells in tumor immune surveillance and identify Akt as a key signaling node in the development of protective memory CD8+ T-cell responses. PMID:28137869

T Cell Receptor Excision Circle (TREC) Monitoring after Allogeneic Stem Cell Transplantation; a Predictive Marker for Complications and Clinical Outcome

PubMed Central

Gaballa, Ahmed; Sundin, Mikael; Stikvoort, Arwen; Abumaree, Muhamed; Uzunel, Mehmet; Sairafi, Darius; Uhlin, Michael

2016-01-01

Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established treatment modality for a variety of malignant diseases as well as for inborn errors of the metabolism or immune system. Regardless of disease origin, good clinical effects are dependent on proper immune reconstitution. T cells are responsible for both the beneficial graft-versus-leukemia (GVL) effect against malignant cells and protection against infections. The immune recovery of T cells relies initially on peripheral expansion of mature cells from the graft and later on the differentiation and maturation from donor-derived hematopoietic stem cells. The formation of new T cells occurs in the thymus and as a byproduct, T cell receptor excision circles (TRECs) are released upon rearrangement of the T cell receptor. Detection of TRECs by PCR is a reliable method for estimating the amount of newly formed T cells in the circulation and, indirectly, for estimating thymic function. Here, we discuss the role of TREC analysis in the prediction of clinical outcome after allogeneic HSCT. Due to the pivotal role of T cell reconstitution we propose that TREC analysis should be included as a key indicator in the post-HSCT follow-up. PMID:27727179

PLAU inferred from a correlation network is critical for suppressor function of regulatory T cells

PubMed Central

He, Feng; Chen, Hairong; Probst-Kepper, Michael; Geffers, Robert; Eifes, Serge; del Sol, Antonio; Schughart, Klaus; Zeng, An-Ping; Balling, Rudi

2012-01-01

Human FOXP3+CD25+CD4+ regulatory T cells (Tregs) are essential to the maintenance of immune homeostasis. Several genes are known to be important for murine Tregs, but for human Tregs the genes and underlying molecular networks controlling the suppressor function still largely remain unclear. Here, we describe a strategy to identify the key genes directly from an undirected correlation network which we reconstruct from a very high time-resolution (HTR) transcriptome during the activation of human Tregs/CD4+ T-effector cells. We show that a predicted top-ranked new key gene PLAU (the plasminogen activator urokinase) is important for the suppressor function of both human and murine Tregs. Further analysis unveils that PLAU is particularly important for memory Tregs and that PLAU mediates Treg suppressor function via STAT5 and ERK signaling pathways. Our study demonstrates the potential for identifying novel key genes for complex dynamic biological processes using a network strategy based on HTR data, and reveals a critical role for PLAU in Treg suppressor function. PMID:23169000

Mosaic Expression of Thyroid Hormone Regulatory Genes Defines Cell Type-Specific Dependency in the Developing Chicken Cerebellum.

PubMed

Delbaere, Joke; Van Herck, Stijn L J; Bourgeois, Nele M A; Vancamp, Pieter; Yang, Shuo; Wingate, Richard J T; Darras, Veerle M

2016-12-01

The cerebellum is a morphologically unique brain structure that requires thyroid hormones (THs) for the correct coordination of key cellular events driving its development. Unravelling the interplay between the multiple factors that can regulate intracellular TH levels is a key step to understanding their role in the regulation of these cellular processes. We therefore investigated the regional/cell-specific expression pattern of TH transporters and deiodinases in the cerebellum using the chicken embryo as a model. In situ hybridisation revealed expression of the TH transporters monocarboxylate transporter 8 (MCT8) and 10 (MCT10), L-type amino acid transporter 1 (LAT1) and organic anion transporting polypeptide 1C1 (OATP1C1) as well as the inactivating type 3 deiodinase (D3) in the fourth ventricle choroid plexus, suggesting a possible contribution of the resulting proteins to TH exchange and subsequent inactivation of excess hormone at the blood-cerebrospinal fluid barrier. Exclusive expression of LAT1 and the activating type 2 deiodinase (D2) mRNA was found at the level of the blood-brain barrier, suggesting a concerted function for LAT1 and D2 in the direct access of active T 3 to the developing cerebellum via the capillary endothelial cells. The presence of MCT8 mRNA in Purkinje cells and cerebellar nuclei during the first 2 weeks of embryonic development points to a potential role of this transporter in the uptake of T 3 in central neurons. At later stages, together with MCT10, detection of MCT8 signal in close association with the Purkinje cell dendritic tree suggests a role of both transporters in TH signalling during Purkinje cell synaptogenesis. MCT10 was also expressed in late-born cells in the rhombic lip lineage with a clear hybridisation signal in the outer external granular layer, indicating a potential role for MCT10 in the proliferation of granule cell precursors. By contrast, expression of D3 in the first-born rhombic lip-derived population may serve as a buffering mechanism against high T 3 levels during early embryonic development, a hypothesis supported by the pattern of expression of a fluorescent TH reporter in this lineage. Overall, this study builds a picture of the TH dependency in multiple cerebellar cell types starting from early embryonic development.

Smooth muscle cell phenotypic switching in stroke.

PubMed

Poittevin, Marine; Lozeron, Pierre; Hilal, Rose; Levy, Bernard I; Merkulova-Rainon, Tatiana; Kubis, Nathalie

2014-06-01

Disruption of cerebral blood flow after stroke induces cerebral tissue injury through multiple mechanisms that are not yet fully understood. Smooth muscle cells (SMCs) in blood vessel walls play a key role in cerebral blood flow control. Cerebral ischemia triggers these cells to switch to a phenotype that will be either detrimental or beneficial to brain repair. Moreover, SMC can be primarily affected genetically or by toxic metabolic molecules. After stroke, this pathological phenotype has an impact on the incidence, pattern, severity, and outcome of the cerebral ischemic disease. Although little research has been conducted on the pathological role and molecular mechanisms of SMC in cerebrovascular ischemic diseases, some therapeutic targets have already been identified and could be considered for further pharmacological development. We examine these different aspects in this review.

An Overview of Lipid Droplets in Cancer and Cancer Stem Cells

PubMed Central

Seco, J.

2017-01-01

For decades, lipid droplets have been considered as the main cellular organelles involved in the fat storage, because of their lipid composition. However, in recent years, some new and totally unexpected roles have been discovered for them: (i) they are active sites for synthesis and storage of inflammatory mediators, and (ii) they are key players in cancer cells and tissues, especially in cancer stem cells. In this review, we summarize the main concepts related to the lipid droplet structure and function and their involvement in inflammatory and cancer processes. PMID:28883835

Molecular pathogenesis of ovarian clear cell carcinoma.

PubMed

Gounaris, Ioannis; Brenton, James D

2015-01-01

Ovarian clear cell carcinoma is a distinct subtype of epithelial ovarian cancer, characterized by an association with endometriosis, glycogen accumulation and resistance to chemotherapy. Key driver events, including ARID1A mutations and HNF1B overexpression, have been recently identified and their functional characterization is ongoing. Additionally, the role of glycogen in promoting the malignant phenotype is coming under scrutiny. Appreciation of the notion that ovarian clear cell carcinoma is essentially an ectopic uterine cancer will hopefully lead to improved animal models of the disease, in turn paving the way for effective treatments.

Role of acetylcholinesterase in lung cancer

PubMed Central

Xi, Hui-Jun; Wu, Ren-Pei; Liu, Jing-Jing; Zhang, Ling-Juan; Li, Zhao-Shen

2015-01-01

Acetylcholinesterase (AChE) plays a key role in catalytic hydrolysis of cholinergic neurotransmitters. Intensive research has proven the involvement of this protein in novel functions, such as cell adhesion, differentiation, and proliferation. In addition, several recent studies have indicated that acetylcholinesterase is potentially a marker and regulator of apoptosis. Importantly, AChE is also a promising tumor suppressor. In this review, we briefly summarize the involvement of AChE in apoptosis and cancer, focusing on the role of AChE in lung cancer, as well as the therapeutic consideration of AChE for cancer therapy. PMID:26273392

Integrative Analysis of DNA Methylation and Gene Expression Data Identifies EPAS1 as a Key Regulator of COPD

PubMed Central

Yoo, Seungyeul; Takikawa, Sachiko; Geraghty, Patrick; Argmann, Carmen; Campbell, Joshua; Lin, Luan; Huang, Tao; Tu, Zhidong; Feronjy, Robert; Spira, Avrum; Schadt, Eric E.; Powell, Charles A.; Zhu, Jun

2015-01-01

Chronic Obstructive Pulmonary Disease (COPD) is a complex disease. Genetic, epigenetic, and environmental factors are known to contribute to COPD risk and disease progression. Therefore we developed a systematic approach to identify key regulators of COPD that integrates genome-wide DNA methylation, gene expression, and phenotype data in lung tissue from COPD and control samples. Our integrative analysis identified 126 key regulators of COPD. We identified EPAS1 as the only key regulator whose downstream genes significantly overlapped with multiple genes sets associated with COPD disease severity. EPAS1 is distinct in comparison with other key regulators in terms of methylation profile and downstream target genes. Genes predicted to be regulated by EPAS1 were enriched for biological processes including signaling, cell communications, and system development. We confirmed that EPAS1 protein levels are lower in human COPD lung tissue compared to non-disease controls and that Epas1 gene expression is reduced in mice chronically exposed to cigarette smoke. As EPAS1 downstream genes were significantly enriched for hypoxia responsive genes in endothelial cells, we tested EPAS1 function in human endothelial cells. EPAS1 knockdown by siRNA in endothelial cells impacted genes that significantly overlapped with EPAS1 downstream genes in lung tissue including hypoxia responsive genes, and genes associated with emphysema severity. Our first integrative analysis of genome-wide DNA methylation and gene expression profiles illustrates that not only does DNA methylation play a ‘causal’ role in the molecular pathophysiology of COPD, but it can be leveraged to directly identify novel key mediators of this pathophysiology. PMID:25569234

Identification of a Novel Pathway That Selectively Modulates Apoptosis of Breast Cancer Cells

PubMed Central

Tinnikov, Alexander A.; Yeung, Kay T.; Das, Sharmistha; Samuels, Herbert H.

2014-01-01

Expression of the nuclear receptor interacting factor 3 (NRIF3) coregulator in a wide variety of breast cancer cells selectively leads to rapid caspase-2–dependent apoptotic cell death. A novel death domain (DD1) was mapped to a 30– amino acid region of NRIF3. Because the cytotoxicity of NRIF3 and DD1 seems to be cell type–specific, these studies suggest that breast cancer cells contain a novel “death switch” that can be specifically modulated by NRIF3 or DD1. Using an MCF-7 cell cDNA library in a yeast two-hybrid screen, we cloned a factor that mediates apoptosis by DD1 and refer to this factor as DD1-interacting factor-1 (DIF-1). DIF-1 is a transcriptional repressor that mediates its effect through SirT1, and this repression is attenuated by the binding of NRIF3/DD1. DIF-1 expression rescues breast cancer cells from NRIF3/DD1-induced apoptosis. Small interfering RNA (siRNA) knockdown of DIF-1 selectively leads to apoptosis of breast cancer cells, further suggesting that DIF-1 plays a key role in NRIF3/DD1-mediated apoptosis. A protein kinase A inhibitor (H89) also elicits apoptosis of breast cancer cells but not of the other cell types examined, and DIF-1 also protects these cells from H89-mediated apoptosis. In addition, H89 incubation results in a rapid increase in NRIF3 levels and siRNA knockdown of NRIF3 protects breast cancer cells from H89-mediated apoptosis. Our results indicate that DIF-1 plays a key role in breast cancer cell survival and further characterizing this pathway may provide important insights into developing novel therapies to selec tively target breast cancer cells for apoptosis. PMID:19190336

Cytoplasmic RAP1 mediates cisplatin resistance of non-small cell lung cancer.

PubMed

Xiao, Lu; Lan, Xiaoying; Shi, Xianping; Zhao, Kai; Wang, Dongrui; Wang, Xuejun; Li, Faqian; Huang, Hongbiao; Liu, Jinbao

2017-05-18

Cytotoxic chemotherapy agents (e.g., cisplatin) are the first-line drugs to treat non-small cell lung cancer (NSCLC) but NSCLC develops resistance to the agent, limiting therapeutic efficacy. Despite many approaches to identifying the underlying mechanism for cisplatin resistance, there remains a lack of effective targets in the population that resist cisplatin treatment. In this study, we sought to investigate the role of cytoplasmic RAP1, a previously identified positive regulator of NF-κB signaling, in the development of cisplatin resistance in NSCLC cells. We found that the expression of cytoplasmic RAP1 was significantly higher in high-grade NSCLC tissues than in low-grade NSCLC; compared with a normal pulmonary epithelial cell line, the A549 NSCLC cells exhibited more cytoplasmic RAP1 expression as well as increased NF-κB activity; cisplatin treatment resulted in a further increase of cytoplasmic RAP1 in A549 cells; overexpression of RAP1 desensitized the A549 cells to cisplatin, and conversely, RAP1 depletion in the NSCLC cells reduced their proliferation and increased their sensitivity to cisplatin, indicating that RAP1 is required for cell growth and has a key mediating role in the development of cisplatin resistance in NSCLC cells. The RAP1-mediated cisplatin resistance was associated with the activation of NF-κB signaling and the upregulation of the antiapoptosis factor BCL-2. Intriguingly, in the small portion of RAP1-depleted cells that survived cisplatin treatment, no induction of NF-κB activity and BCL-2 expression was observed. Furthermore, in established cisplatin-resistant A549 cells, RAP1 depletion caused BCL2 depletion, caspase activation and dramatic lethality to the cells. Hence, our results demonstrate that the cytoplasmic RAP1-NF-κB-BCL2 axis represents a key pathway to cisplatin resistance in NSCLC cells, identifying RAP1 as a marker and a potential therapeutic target for cisplatin resistance of NSCLC.

Bruton tyrosine kinase (Btk) suppresses osteoblastic differentiation.

PubMed

Kaneshiro, Shoichi; Ebina, Kosuke; Shi, Kenrin; Yoshida, Kiyoshi; Otsuki, Dai; Yoshikawa, Hideki; Higuchi, Chikahisa

2015-09-01

The Tec family of nonreceptor tyrosine kinases has been shown to play a key role in inflammation and bone destruction. Bruton tyrosine kinase (Btk) has been the most widely studied because of its critical role in B cells. Furthermore, recent evidence has demonstrated that blocking Btk signaling is effective in ameliorating lymphoma progression and experimental arthritis. The role of Btk in osteoblastic differentiation has not been well elucidated. In this study, we demonstrated the role of Btk in osteoblastic differentiation and investigated the effects of a Btk inhibitor on osteoblastic differentiation in mouse preosteoblastic MC3T3-E1 cells, primary calvarial osteoblasts, and bone marrow stromal ST2 cells. Btk expression was detected in all three cell lines. Btk inhibition stimulated mRNA expression of osteoblastic markers (alkaline phosphatase, osteocalcin, and osterix) and promoted mineralization of the extracellular matrix. In addition, Btk knockdown caused increased mRNA expression of osteoblastic markers. Furthermore, Btk inhibition suppressed the phosphorylation of mitogen-activated protein kinase (MAPK), nuclear factor kappa B (NFκB), and protein kinase Cα (PKCα). Our results indicate that Btk may regulate osteoblastic differentiation through the MAPK, NFκB, and PKCα signaling pathways.

Defining the roles for Vpr in HIV-1-associated neuropathogenesis

PubMed Central

James, Tony; Nonnemacher, Michael R.; Wigdahl, Brian; Krebs, Fred C.

2016-01-01

It is increasingly evident that the human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) has a unique role in neuropathogenesis. Its ability to induce G2/M arrest coupled with its capacity to increase viral gene transcription gives it a unique role in sustaining viral replication and aiding in the establishment and maintenance of a systemic infection. The requirement of Vpr for HIV-1 infection and replication in cells of monocytic origin (a key lineage of cells involved in HIV-1 neuroinvasion) suggests an important role in establishing and sustaining infection in the central nervous system (CNS). Contributions of Vpr to neuropathogenesis can be expanded further through (i) naturally occurring HIV-1 sequence variation that results in functionally divergent Vpr variants; (ii) the dual activities of Vpr as a intracellular protein delivered and expressed during HIV-1 infection and as an extracellular protein that can act on neighboring, uninfected cells; (iii) cell type-dependent consequences of Vpr expression and exposure, including cell cycle arrest, metabolic dysregulation, and cytotoxicity; and (iv) the effects of Vpr on exosome-based intercellular communication in the CNS. Revealing the effects of this pleiotropic viral protein is an essential part of a greater understanding of HIV-1-associated pathogenesis and potential approaches to treating and preventing disease caused by HIV-1 infection. PMID:27056720

PINK1/Parkin-mediated mitophagy alleviates chlorpyrifos-induced apoptosis in SH-SY5Y cells.

PubMed

Dai, Hongmei; Deng, Yuanying; Zhang, Jie; Han, Hailong; Zhao, Mingyi; Li, Ying; Zhang, Chen; Tian, Jing; Bing, Guoying; Zhao, Lingling

2015-08-06

Chlorpyrifos (CPF) is one of the most widely used organophosphorous insecticides. There are links between CPF exposure and neurological disorders. Mitochondrial damage has been implicated to play a key role in CPF-induced neurotoxicity. Mitophagy, the selective autophagic elimination of mitochondria, is an important mitochondrial quality control mechanism. However, the role of mitophagy in CPF-induced neurotoxicity remains unclear. In this study, CPF-caused mitochondrial damage, role and mechanism of mitophagy on CPF-induced neuroapoptosis were extensively studied by using SH-SY5Y cells. We showed that CPF treatment caused mitochondrial fragmentation, excessive ROS generation and mitochondrial depolarization, thus led to cell apoptosis. Moreover, CPF treatment also resulted in increased colocalizaton of mitochondria with LC3, decreased levels of mitochondrial proteins, PINK1 stabilization and mitochondrial accumulation of Parkin. These data suggested that CPF treatment induced PINK1/Parkin-mediated mitophagy in SH-SY5Y cells. Furthermore, knockdown of Parkin dramatically increased CPF-induced neuroapoptosis. On the other hand, overexpression of Parkin markedly alleviated CPF-induced SH-SY5Y cell apoptosis. Together, these findings implicate a protective role of PINK1/Parkin-mediated mitophagy against neuroapoptosis and that enhancing mitophagy provides a potential therapeutic strategy for CPF-induced neurological disorders. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Can hi-jacking hypoxia inhibit extracellular vesicles in cancer?

PubMed

Lowry, Michelle C; O'Driscoll, Lorraine

2018-06-01

Increasing evidence indicates that extracellular vesicles (EVs) are key players in undesirable cell-cell communication in cancer. However, the release of EVs is not unique to cancer cells; normal cells release EVs to perform physiological roles. Thus, selective inhibition of EV release from cancer cells is desirable. Hypoxia contributes to tumour development and aggressiveness. EV quantities and thus undesirable communications are substantially increased in hypoxia. Targeting hypoxia could selectively inhibit EV release from tumour cells without disturbing physiologically relevant EVs. The unfavourable association between hypoxia and EV release is evident in multiple tumour types; therefore, targeting hypoxia could have a broad therapeutic benefit. Copyright © 2018 Elsevier Ltd. All rights reserved.

Conditional knockdown of BCL2A1 reveals rate-limiting roles in BCR-dependent B-cell survival

PubMed Central

Sochalska, M; Ottina, E; Tuzlak, S; Herzog, S; Herold, M; Villunger, A

2016-01-01

Bcl2 family proteins control mitochondrial apoptosis and its members exert critical cell type and differentiation stage-specific functions, acting as barriers against autoimmunity or transformation. Anti-apoptotic Bcl2a1/Bfl1/A1 is frequently deregulated in different types of blood cancers in humans but its physiological role is poorly understood as quadruplication of the Bcl2a1 gene locus in mice hampers conventional gene targeting strategies. Transgenic overexpression of A1, deletion of the A1-a paralogue or constitutive knockdown in the hematopoietic compartment of mice by RNAi suggested rate-limiting roles in lymphocyte development, granulopoiesis and mast cell activation. Here we report on the consequences of conditional knockdown of A1 protein expression using a reverse transactivator (rtTA)-driven approach that highlights a critical role for this Bcl2 family member in the maintenance of mature B-cell homeostasis. Furthermore, we define the A1/Bim (Bcl-2 interacting mediator of cell death) axis as a target of key kinases mediating B-cell receptor (BCR)-dependent survival signals, such as, spleen tyrosine kinase (Syk) and Brutons tyrosine kinase (Btk). As such, A1 represents a putative target for the treatment of B-cell-related pathologies depending on hyperactivation of BCR-emanating survival signals and loss of A1 expression accounts, in part, for the pro-apoptotic effects of Syk- or Btk inhibitors that rely on the ‘BH3-only' protein Bim for cell killing. PMID:26450454

A mutation in the mitochondrial protein UQCRB promotes angiogenesis through the generation of mitochondrial reactive oxygen species

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

Chang, Junghwa; Jung, Hye Jin; Jeong, Seung Hun

2014-12-12

Highlights: • We constructed mitochondrial protein UQCRB mutant stable cell lines on the basis of a human case report. • These mutant cell lines exhibit pro-angiogenic activity with enhanced VEGF expression. • Proliferation of mutant cell lines was regulated by UQCRB inhibitors. • UQCRB may have a functional role in angiogenesis. - Abstract: Ubiquinol-cytochrome c reductase binding protein (UQCRB) is one of the subunits of mitochondrial complex III and is a target protein of the natural anti-angiogenic small molecule terpestacin. Previously, the biological role of UQCRB was thought to be limited to the maintenance of complex III. However, the identificationmore » and validation of UQCRB as a target protein of terpestacin enabled the role of UQCRB in oxygen sensing and angiogenesis to be elucidated. To explore the biological role of this protein further, UQCRB mutant stable cell lines were generated on the basis of a human case report. We demonstrated that these cell lines exhibited glycolytic and pro-angiogenic activities via mitochondrial reactive oxygen species (mROS)-mediated HIF1 signal transduction. Furthermore, a morphological abnormality in mitochondria was detected in UQCRB mutant stable cell lines. In addition, the proliferative effect of the UQCRB mutants was significantly regulated by the UQCRB inhibitors terpestacin and A1938. Collectively, these results provide a molecular basis for UQCRB-related biological processes and reveal potential key roles of UQCRB in angiogenesis and mitochondria-mediated metabolic disorders.« less

An Overview of Power Electronics Applications in Fuel Cell Systems: DC and AC Converters

PubMed Central

Ali, M. S.; Kamarudin, S. K.; Masdar, M. S.; Mohamed, A.

2014-01-01

Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter. PMID:25478581

An overview of power electronics applications in fuel cell systems: DC and AC converters.

PubMed

Ali, M S; Kamarudin, S K; Masdar, M S; Mohamed, A

2014-01-01

Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.

Mitochondrial Dynamics Impacts Stem Cell Identity and Fate Decisions by Regulating a Nuclear Transcriptional Program.

PubMed

Khacho, Mireille; Clark, Alysen; Svoboda, Devon S; Azzi, Joelle; MacLaurin, Jason G; Meghaizel, Cynthia; Sesaki, Hiromi; Lagace, Diane C; Germain, Marc; Harper, Mary-Ellen; Park, David S; Slack, Ruth S

2016-08-04

Regulated mechanisms of stem cell maintenance are key to preventing stem cell depletion and aging. While mitochondrial morphology plays a fundamental role in tissue development and homeostasis, its role in stem cells remains unknown. Here, we uncover that mitochondrial dynamics regulates stem cell identity, self-renewal, and fate decisions by orchestrating a transcriptional program. Manipulation of mitochondrial structure, through OPA1 or MFN1/2 deletion, impaired neural stem cell (NSC) self-renewal, with consequent age-dependent depletion, neurogenesis defects, and cognitive impairments. Gene expression profiling revealed ectopic expression of the Notch self-renewal inhibitor Botch and premature induction of transcription factors that promote differentiation. Changes in mitochondrial dynamics regulate stem cell fate decisions by driving a physiological reactive oxygen species (ROS)-mediated process, which triggers a dual program to suppress self-renewal and promote differentiation via NRF2-mediated retrograde signaling. These findings reveal mitochondrial dynamics as an upstream regulator of essential mechanisms governing stem cell self-renewal and fate decisions through transcriptional programming. Copyright © 2016 Elsevier Inc. All rights reserved.

Distinct but Concerted Roles of ATR, DNA-PK, and Chk1 in Countering Replication Stress during S Phase

PubMed Central

Buisson, Rémi; Boisvert, Jessica L.; Benes, Cyril H.; Zou, Lee

2015-01-01

The ATR-Chk1 pathway is critical for DNA damage responses and cell cycle progression. Chk1 inhibition is more deleterious to cycling cells than ATR inhibition, raising questions about ATR and Chk1 functions in the absence of extrinsic replication stress. Here, we show that a key role of ATR in S phase is to coordinate RRM2 accumulation and origin firing. ATR inhibitor (ATRi) induces massive ssDNA accumulation and replication catastrophe in a fraction of early S-phase cells. In other S-phase cells, however, ATRi induces moderate ssDNA and triggers a DNA-PK and Chk1-mediated backup pathway to suppress origin firing. The backup pathway creates a threshold such that ATRi selectively kills cells under high replication stress, whereas Chk1 inhibitor induces cell death at a lower threshold. The levels of ATRi-induced ssDNA correlate with ATRi sensitivity in a panel of cell lines, suggesting that ATRi-induced ssDNA could be predictive of ATRi sensitivity in cancer cells. PMID:26365377

B cell–derived IL-6 initiates spontaneous germinal center formation during systemic autoimmunity

PubMed Central

Arkatkar, Tanvi

2017-01-01

Recent studies have identified critical roles for B cells in triggering autoimmune germinal centers (GCs) in systemic lupus erythematosus (SLE) and other disorders. The mechanisms whereby B cells facilitate loss of T cell tolerance, however, remain incompletely defined. Activated B cells produce interleukin 6 (IL-6), a proinflammatory cytokine that promotes T follicular helper (TFH) cell differentiation. Although B cell IL-6 production correlates with disease severity in humoral autoimmunity, whether B cell–derived IL-6 is required to trigger autoimmune GCs has not, to our knowledge, been addressed. Here, we report the unexpected finding that a lack of B cell–derived IL-6 abrogates spontaneous GC formation in mouse SLE, resulting in loss of class-switched autoantibodies and protection from systemic autoimmunity. Mechanistically, B cell IL-6 production was enhanced by IFN-γ, consistent with the critical roles for B cell–intrinsic IFN-γ receptor signals in driving autoimmune GC formation. Together, these findings identify a key mechanism whereby B cells drive autoimmunity via local IL-6 production required for TFH differentiation and autoimmune GC formation. PMID:28899868

Laminins and cancer stem cells: Partners in crime?

PubMed

Qin, Yan; Rodin, Sergey; Simonson, Oscar E; Hollande, Frédéric

2017-08-01

As one of the predominant protein families within the extracellular matrix both structurally and functionally, laminins have been shown to be heavily involved in tumor progression and drug resistance. Laminins participate in key cellular events for tumor angiogenesis, cell invasion and metastasis development, including the regulation of epithelial-mesenchymal transition and basement membrane remodeling, which are tightly associated with the phenotypic characteristics of stem-like cells, particularly in the context of cancer. In addition, a great deal of studies and reports has highlighted the critical roles of laminins in modulating stem cell phenotype and differentiation, as part of the stem cell niche. Stemming from these discoveries a growing body of literature suggests that laminins may act as regulators of cancer stem cells, a tumor cell subpopulation that plays an instrumental role in long-term cancer maintenance, metastasis development and therapeutic resistance. The accumulating evidence in this emerging research area suggests that laminins represent potential therapeutic targets for anti-cancer treatments against cancer stem cells, and that they may be used as predictive and prognostic markers to inform clinical management and improve patient survival. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of airborne particulate matter on alternative pre-mRNA splicing in colon cancer cells.

PubMed

Buggiano, Valeria; Petrillo, Ezequiel; Alló, Mariano; Lafaille, Celina; Redal, María Ana; Alghamdi, Mansour A; Khoder, Mamdouh I; Shamy, Magdy; Muñoz, Manuel J; Kornblihtt, Alberto R

2015-07-01

Alternative pre-mRNA splicing plays key roles in determining tissue- and species-specific cell differentiation as well as in the onset of hereditary disease and cancer, being controlled by multiple post- and co-transcriptional regulatory mechanisms. We report here that airborne particulate matter, resulting from industrial pollution, inhibits expression and specifically affects alternative splicing at the 5' untranslated region of the mRNA encoding the bone morphogenetic protein BMP4 in human colon cells in culture. These effects are consistent with a previously reported role for BMP4 in preventing colon cancer development, suggesting that ingestion of particulate matter could contribute to the onset of colon cell proliferation. We also show that the underlying mechanism might involve changes in transcriptional elongation. This is the first study to demonstrate that particulate matter causes non-pleiotropic changes in alternative splicing. Copyright © 2015 Elsevier Inc. All rights reserved.

P21 and p27: roles in carcinogenesis and drug resistance.

PubMed

Abukhdeir, Abde M; Park, Ben Ho

2008-07-01

Human cancers arise from an imbalance of cell growth and cell death. Key proteins that govern this balance are those that mediate the cell cycle. Several different molecular effectors have been identified that tightly regulate specific phases of the cell cycle, including cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors. Notably, loss of expression or function of two G1-checkpoint CDK inhibitors - p21 (CDKN1A) and p27 (CDKN1B) - has been implicated in the genesis or progression of many human malignancies. Additionally, there is a growing body of evidence suggesting that functional loss of p21 or p27 can mediate a drug-resistance phenotype. However, reports in the literature have also suggested p21 and p27 can promote tumours, indicating a paradoxical effect. Here, we review historic and recent studies of these two CDK inhibitors, including their identification, function, importance to carcinogenesis and finally their roles in drug resistance.

Microtubule catastrophe and rescue.

PubMed

Gardner, Melissa K; Zanic, Marija; Howard, Jonathon

2013-02-01

Microtubules are long cylindrical polymers composed of tubulin subunits. In cells, microtubules play an essential role in architecture and motility. For example, microtubules give shape to cells, serve as intracellular transport tracks, and act as key elements in important cellular structures such as axonemes and mitotic spindles. To accomplish these varied functions, networks of microtubules in cells are very dynamic, continuously remodeling through stochastic length fluctuations at the ends of individual microtubules. The dynamic behavior at the end of an individual microtubule is termed 'dynamic instability'. This behavior manifests itself by periods of persistent microtubule growth interrupted by occasional switching to rapid shrinkage (called microtubule 'catastrophe'), and then by switching back from shrinkage to growth (called microtubule 'rescue'). In this review, we summarize recent findings which provide new insights into the mechanisms of microtubule catastrophe and rescue, and discuss the impact of these findings in regards to the role of microtubule dynamics inside of cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

Microglia and neuroprotection: implications for Alzheimer's disease.

PubMed

Streit, Wolfgang J

2005-04-01

The first part of this paper summarizes some of the key observations from experimental work in animals that support a role of microglia as neuroprotective cells after acute neuronal injury. These studies point towards an important role of neuronal-microglial crosstalk in the facilitation of neuroprotection. Conceptually, injured neurons are thought to generate rescue signals that trigger microglial activation and, in turn, activated microglia produce trophic or other factors that help damaged neurons recover from injury. Against this background, the second part of this paper summarizes recent work from postmortem studies conducted in humans that have revealed the occurrence of senescent, or dystrophic, microglial cells in the aged and Alzheimer's disease brain. These findings suggest that microglial cells become increasingly dysfunctional with advancing age and that a loss of microglial cell function may involve a loss of neuroprotective properties that could contribute to the development of aging-related neurodegeneration.

The role of nanostructured mesoporous silicon in discriminating in vitro calcification for electrospun composite tissue engineering scaffolds

NASA Astrophysics Data System (ADS)

Fan, Dongmei; Akkaraju, Giridhar R.; Couch, Ernest F.; CanhamCurrent Address, Intrinsiq Materials Ltd, Geraldine Road, Malvern Wr14 3SZ Uk, Leigh T.; Coffer, Jeffery L.

2011-02-01

The impact of mesoporous silicon (PSi) particles-embedded either on the surface, or totally encapsulated within electrospun poly (ε-caprolactone) (PCL) fibers-on its properties as a tissue engineering scaffold is assessed. Our findings suggest that the resorbable porous silicon component can sensitively accelerate the necessary calcification process in such composites. Calcium phosphate deposition on the scaffolds was measured via in vitro calcification assays both at acellular and cellular levels. Extensive attachment of fibroblasts, human adult mesenchymal stem cells, and mouse stromal cells to the scaffold were observed. Complementary cell differentiation assays and ultrastructural measurements were also carried out; the levels of alkaline phosphatase expression, a specific biomarker for mesenchymal stem cell differentiation, show that the scaffolds have the ability to mediate such processes, and that the location of the Si plays a key role in levels of expression.

The role of the cell wall in fungal pathogenesis

PubMed Central

Arana, David M.; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso‐Monge, Rebeca; Pla, Jesús

2009-01-01

Summary Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections. PMID:21261926

Rab22a enhances CD147 recycling and is required for lung cancer cell migration and invasion.

PubMed

Zhou, Yang; Wu, Bo; Li, Jiang-Hua; Nan, Gang; Jiang, Jian-Li; Chen, Zhi-Nan

2017-08-01

Rab22a is a member of the Ras-related small GTPase family, which plays a key role in regulating the recycling of cargo proteins entering cells through clathrin-independent endocytosis (CIE). Rab22a is overexpressed in different cancer types, including liver cancer, malignant melanoma, ovarian cancer and osteosarcoma. However, its oncogenic role remains unknown. In this study, we found that silencing of Rab22a suppressed the migration and invasion of lung cancer cells. Furthermore, Rab22a interacts with CD147, and knockdown of Rab22a blocks CD147 recycling and promotes CD147 degradation. Taken together, our findings indicate that Rab22a enhances recycling of CD147, which is required for lung cancer cell migration and invasion,and targeting CD147 recycling may be a rational strategy for lung cancer therapy. Copyright © 2017. Published by Elsevier Inc.

The role of syncytins in human reproduction and reproductive organ cancers.

PubMed

Soygur, Bikem; Sati, Leyla

2016-11-01

Human life begins with sperm and oocyte fusion. After fertilization, various fusion events occur during human embryogenesis and morphogenesis. For example, the fusion of trophoblastic cells constitutes a key process for normal placental development. Fusion in the placenta is facilitated by syncytin 1 and syncytin 2. These syncytins arose from retroviral sequences that entered the primate genome 25 million and more than 40 million years ago respectively. About 8% of the human genome consists of similar human endogenous retroviral (HERVs) sequences. Many are inactive because of mutations or deletions. However, the role of the few that remain transcriptionally active has not been fully elucidated. Syncytin proteins maintain cell-cell fusogenic activity based on ENV: gene-mediated viral cell entry. In this review, we summarize how syncytins and their receptors are involved in fusion events during human reproduction. The significance of syncytins in tumorigenesis is also discussed. © 2016 Society for Reproduction and Fertility.

Role of Cell Cycle Regulation and MLH1, A Key DNA Mismatch Repair Protein, In Adaptive Survival Responses. Final Report

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

David A. Boothman

1999-08-11

Due to several interesting findings on both adaptive survival responses (ASRs) and DNA mismatch repair (MMR), this grant was separated into two discrete Specific Aim sets (each with their own discrete hypotheses). The described experiments were simultaneously performed.

The cytokine macrophage migration inhibitory factor (MIF) acts as a neurotrophin in the developing inner ear of the zebrafish, Danio rerio

PubMed Central

Shen, Yu-chi; Thompson, Deborah L.; Kuah, Meng-Kiat; Wong, Kah-Loon; Wu, Karen L.; Linn, Stephanie A.; Jewett, Ethan M.; Shu-Chien, Alexander Chong; Barald, Kate F.

2012-01-01

Macrophage migration inhibitory factor (MIF) plays versatile roles in the immune system. MIF is also widely expressed during embryonic development, particularly in the nervous system, although its roles in neural development are only beginning to be understood. Evidence from frogs, mice and zebrafish suggests that MIF has a major role as a neurotrophin in the early development of sensory systems, including the auditory system. Here we show that the zebrafish mif pathway is required for both sensory hair cell (HC) and sensory neuronal cell survival in the ear, for HC differentiation, semicircular canal formation, statoacoustic ganglion (SAG) development, and lateral line HC differentiation. This is consistent with our findings that MIF is expressed in the developing mammalian and avian auditory systems and promotes mouse and chick SAG neurite outgrowth and neuronal survival, demonstrating key instructional roles for MIF in vertebrate otic development. PMID:22210003

Swimming motility plays a key role in the stochastic dynamics of cell clumping

NASA Astrophysics Data System (ADS)

Qi, Xianghong; Nellas, Ricky B.; Byrn, Matthew W.; Russell, Matthew H.; Bible, Amber N.; Alexandre, Gladys; Shen, Tongye

2013-04-01

Dynamic cell-to-cell interactions are a prerequisite to many biological processes, including development and biofilm formation. Flagellum induced motility has been shown to modulate the initial cell-cell or cell-surface interaction and to contribute to the emergence of macroscopic patterns. While the role of swimming motility in surface colonization has been analyzed in some detail, a quantitative physical analysis of transient interactions between motile cells is lacking. We examined the Brownian dynamics of swimming cells in a crowded environment using a model of motorized adhesive tandem particles. Focusing on the motility and geometry of an exemplary motile bacterium Azospirillum brasilense, which is capable of transient cell-cell association (clumping), we constructed a physical model with proper parameters for the computer simulation of the clumping dynamics. By modulating mechanical interaction (‘stickiness’) between cells and swimming speed, we investigated how equilibrium and active features affect the clumping dynamics. We found that the modulation of active motion is required for the initial aggregation of cells to occur at a realistic time scale. Slowing down the rotation of flagellar motors (and thus swimming speeds) is correlated to the degree of clumping, which is consistent with the experimental results obtained for A. brasilense.

Transient receptor potential cation channel, subfamily V, member 4 and airway sensory afferent activation: Role of adenosine triphosphate.

PubMed

Bonvini, Sara J; Birrell, Mark A; Grace, Megan S; Maher, Sarah A; Adcock, John J; Wortley, Michael A; Dubuis, Eric; Ching, Yee-Man; Ford, Anthony P; Shala, Fisnik; Miralpeix, Montserrat; Tarrason, Gema; Smith, Jaclyn A; Belvisi, Maria G

2016-07-01

Sensory nerves innervating the airways play an important role in regulating various cardiopulmonary functions, maintaining homeostasis under healthy conditions and contributing to pathophysiology in disease states. Hypo-osmotic solutions elicit sensory reflexes, including cough, and are a potent stimulus for airway narrowing in asthmatic patients, but the mechanisms involved are not known. Transient receptor potential cation channel, subfamily V, member 4 (TRPV4) is widely expressed in the respiratory tract, but its role as a peripheral nociceptor has not been explored. We hypothesized that TRPV4 is expressed on airway afferents and is a key osmosensor initiating reflex events in the lung. We used guinea pig primary cells, tissue bioassay, in vivo electrophysiology, and a guinea pig conscious cough model to investigate a role for TRPV4 in mediating sensory nerve activation in vagal afferents and the possible downstream signaling mechanisms. Human vagus nerve was used to confirm key observations in animal tissues. Here we show TRPV4-induced activation of guinea pig airway-specific primary nodose ganglion cells. TRPV4 ligands and hypo-osmotic solutions caused depolarization of murine, guinea pig, and human vagus and firing of Aδ-fibers (not C-fibers), which was inhibited by TRPV4 and P2X3 receptor antagonists. Both antagonists blocked TRPV4-induced cough. This study identifies the TRPV4-ATP-P2X3 interaction as a key osmosensing pathway involved in airway sensory nerve reflexes. The absence of TRPV4-ATP-mediated effects on C-fibers indicates a distinct neurobiology for this ion channel and implicates TRPV4 as a novel therapeutic target for neuronal hyperresponsiveness in the airways and symptoms, such as cough. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Identification of the Key Genes and Pathways in Esophageal Carcinoma.

PubMed

Su, Peng; Wen, Shiwang; Zhang, Yuefeng; Li, Yong; Xu, Yanzhao; Zhu, Yonggang; Lv, Huilai; Zhang, Fan; Wang, Mingbo; Tian, Ziqiang

2016-01-01

Objective . Esophageal carcinoma (EC) is a frequently common malignancy of gastrointestinal cancer in the world. This study aims to screen key genes and pathways in EC and elucidate the mechanism of it. Methods . 5 microarray datasets of EC were downloaded from Gene Expression Omnibus. Differentially expressed genes (DEGs) were screened by bioinformatics analysis. Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network construction were performed to obtain the biological roles of DEGs in EC. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the expression level of DEGs in EC. Results . A total of 1955 genes were filtered as DEGs in EC. The upregulated genes were significantly enriched in cell cycle and the downregulated genes significantly enriched in Endocytosis. PPI network displayed CDK4 and CCT3 were hub proteins in the network. The expression level of 8 dysregulated DEGs including CDK4, CCT3, THSD4, SIM2, MYBL2, CENPF, CDCA3, and CDKN3 was validated in EC compared to adjacent nontumor tissues and the results were matched with the microarray analysis. Conclusion . The significantly DEGs including CDK4, CCT3, THSD4, and SIM2 may play key roles in tumorigenesis and development of EC involved in cell cycle and Endocytosis.

Aryl hydrocarbon receptor (AHR) is a potential tumour suppressor in pituitary adenomas.

PubMed

Formosa, R; Borg, J; Vassallo, J

2017-08-01

Pituitary adenomas (PA) represent the largest group of intracranial neoplasms and yet the molecular mechanisms driving this disease remain largely unknown. The aim of this study was to use a high-throughput screening method to identify molecular pathways that may be playing a significant and consistent role in PA. RNA profiling using microarrays on eight local PAs identified the aryl hydrocarbon receptor (AHR) signalling pathway as a key canonical pathway downregulated in all PA types. This was confirmed by real-time PCR in 31 tumours. The AHR has been shown to regulate cell cycle progression in various cell types; however, its role in pituitary tissue has never been investigated. In order to validate the role of AHR in PA behaviour, further functional studies were undertaken. Over-expression of AHR in GH3 cells revealed a tumour suppressor potential independent of exogenous ligand activation by benzo α-pyrene (BαP). Cell cycle analysis and quantitative PCR of cell cycle regulator genes revealed that both unstimulated and BαP-stimulated AHR reduced E2F-driven transcription and altered expression of cell cycle regulator genes, thus increasing the percentage of cells in G 0 /G 1 phase and slowing the proliferation rate of GH3 cells. Co-immunoprecipitation confirmed the interaction between AHR and retinoblastoma (Rb1) protein supporting this as a functional mechanism for the observed reduction. Endogenous Ahr reduction using silencing RNA confirmed the tumour suppressive function of the Ahr. These data support a mechanistic pathway for the putative tumour suppressive role of AHR specifically in PA, possibly through its role as a cell cycle co-regulator, even in the absence of exogenous ligands. © 2017 The authors.

Aryl hydrocarbon receptor (AHR) is a potential tumour suppressor in pituitary adenomas

PubMed Central

Formosa, R; Borg, J

2017-01-01

Pituitary adenomas (PA) represent the largest group of intracranial neoplasms and yet the molecular mechanisms driving this disease remain largely unknown. The aim of this study was to use a high-throughput screening method to identify molecular pathways that may be playing a significant and consistent role in PA. RNA profiling using microarrays on eight local PAs identified the aryl hydrocarbon receptor (AHR) signalling pathway as a key canonical pathway downregulated in all PA types. This was confirmed by real-time PCR in 31 tumours. The AHR has been shown to regulate cell cycle progression in various cell types; however, its role in pituitary tissue has never been investigated. In order to validate the role of AHR in PA behaviour, further functional studies were undertaken. Over-expression of AHR in GH3 cells revealed a tumour suppressor potential independent of exogenous ligand activation by benzo α-pyrene (BαP). Cell cycle analysis and quantitative PCR of cell cycle regulator genes revealed that both unstimulated and BαP-stimulated AHR reduced E2F-driven transcription and altered expression of cell cycle regulator genes, thus increasing the percentage of cells in G0/G1 phase and slowing the proliferation rate of GH3 cells. Co-immunoprecipitation confirmed the interaction between AHR and retinoblastoma (Rb1) protein supporting this as a functional mechanism for the observed reduction. Endogenous Ahr reduction using silencing RNA confirmed the tumour suppressive function of the Ahr. These data support a mechanistic pathway for the putative tumour suppressive role of AHR specifically in PA, possibly through its role as a cell cycle co-regulator, even in the absence of exogenous ligands. PMID:28649092

A novel role for antizyme inhibitor 2 as a regulator of serotonin and histamine biosynthesis and content in mouse mast cells.

PubMed

Acosta-Andrade, Carlos; Lambertos, Ana; Urdiales, José L; Sánchez-Jiménez, Francisca; Peñafiel, Rafael; Fajardo, Ignacio

2016-10-01

Antizymes and antizyme inhibitors are key regulatory proteins of polyamine levels by affecting ornithine decarboxylase and polyamine uptake. Our previous studies indicated a metabolic interplay among polyamines, histamine and serotonin in mast cells, and demonstrated that polyamines are present in mast cell secretory granules, being important for histamine storage and serotonin levels. Recently, the novel antizyme inhibitor-2 (AZIN2) was proposed as a local regulator of polyamine biosynthesis in association with mast cell serotonin-containing granules. To gain insight into the role of AZIN2 in the biosynthesis and storage of serotonin and histamine, we have generated bone marrow derived mast cells (BMMCs) from both wild-type and transgenic Azin2 hypomorphic mice, and have analyzed polyamines, serotonin and histamine contents, and some elements of their metabolisms. Azin2 hypomorphic BMMCs did not show major mast cell phenotypic alterations as judged by morphology and specific mast cell proteases. However, compared to wild-type controls, these cells showed reduced spermidine and spermine levels, and diminished growth rate. Serotonin levels were also reduced, whereas histamine levels tended to increase. Accordingly, tryptophan hydroxylase-1 (TPH1; the key enzyme for serotonin biosynthesis) mRNA expression and protein levels were reduced, whereas histidine decarboxylase (the enzyme responsible for histamine biosynthesis) enzymatic activity was increased. Furthermore, microphtalmia-associated transcription factor, an element involved in the regulation of Tph1 expression, was reduced. Taken together, our results show, for the first time, an element of polyamine metabolism -AZIN2-, so far described as exclusively devoted to the control of polyamine concentrations, involved in regulating the biosynthesis and content of other amines like serotonin and histamine.

Mitofusin 1 degradation is induced by a disruptor of mitochondrial calcium homeostasis, CGP37157: a role in apoptosis in prostate cancer cells.

PubMed

Choudhary, Vivek; Kaddour-Djebbar, Ismail; Alaisami, Rabei; Kumar, M Vijay; Bollag, Wendy B

2014-05-01

Mitochondria constantly divide (mitochondrial fission) and fuse (mitochondrial fusion) in a normal cell. Disturbances in the balance between these two physiological processes may lead to cell dysfunction or to cell death. Induction of cell death is the prime goal of prostate cancer chemotherapy. Our previous study demonstrated that androgens increase the expression of a mitochondrial protein involved in fission and facilitate an apoptotic response to CGP37157 (CGP), an inhibitor of mitochondrial calcium efflux, in prostate cancer cells. However, the regulation and role of mitochondrial fusion proteins in the death of these cells have not been examined. Therefore, our objective was to investigate the effect of CGP on a key mitochondrial fusion protein, mitofusin 1 (Mfn1), and the role of Mfn1 in prostate cancer cell apoptosis. We used various prostate cancer cell lines and western blot analysis, qRT-PCR, siRNA, M30 apoptosis assay and immunoprecipitation techniques to determine mechanisms regulating Mfn1. Treatment of prostate cancer cells with CGP resulted in selective degradation of Mfn1. Mfn1 ubiquitination was detected following immunoprecipitation of overexpressed Myc-tagged Mfn1 protein from CGP-treated cells, and treatment with the proteasomal inhibitor lactacystin, as well as siRNA-mediated knockdown of the E3 ubiquitin ligase March5, protected Mfn1 from CGP-induced degradation. These data indicate the involvement of the ubiquitin-proteasome pathway in CGP-induced degradation of Mfn1. We also demonstrated that downregulation of Mfn1 by siRNA enhanced the apoptotic response of LNCaP cells to CGP, suggesting a likely pro-survival role for Mfn1 in these cells. Our results suggest that manipulation of mitofusins may provide a novel therapeutic advantage in treating prostate cancer.

Availability of the key metabolic substrates dictates the respiratory response of cancer cells to the mitochondrial uncoupling.

PubMed

Zhdanov, Alexander V; Waters, Alicia H C; Golubeva, Anna V; Dmitriev, Ruslan I; Papkovsky, Dmitri B

2014-01-01

Active glycolysis and glutaminolysis provide bioenergetic stability of cancer cells in physiological conditions. Under hypoxia, metabolic and mitochondrial disorders, or pharmacological treatment, a deficit of key metabolic substrates may become life-threatening to cancer cells. We analysed the effects of mitochondrial uncoupling by FCCP on the respiration of cells fed by different combinations of Glc, Gal, Gln and Pyr. In cancer PC12 and HCT116 cells, a large increase in O2 consumption rate (OCR) upon uncoupling was only seen when Gln was combined with either Glc or Pyr. Inhibition of glutaminolysis with BPTES abolished this effect. Despite the key role of Gln, addition of FCCP inhibited respiration and induced apoptosis in cells supplied with Gln alone or Gal/Gln. For all substrate combinations, amplitude of respiratory responses to FCCP did not correlate with Akt, Erk and AMPK phosphorylation, cellular ATP, and resting OCR, mitochondrial Ca(2+) or membrane potential. However, we propose that proton motive force could modulate respiratory response to FCCP by regulating mitochondrial transport of Gln and Pyr, which decreases upon mitochondrial depolarisation. As a result, an increase in respiration upon uncoupling is abolished in cells, deprived of Gln or Pyr (Glc). Unlike PC12 or HCT116 cells, mouse embryonic fibroblasts were capable of generating pronounced response to FCCP when deprived of Gln, thus exhibiting lower dependence on glutaminolysis. Overall, the differential regulation of the respiratory response to FCCP by metabolic environment suggests that mitochondrial uncoupling has a potential for substrate-specific inhibition of cell function, and can be explored for selective cancer treatment. © 2013.

Adipose tissue and breast epithelial cells: a dangerous dynamic duo in breast cancer.

PubMed

Wang, Yuan-Yuan; Lehuédé, Camille; Laurent, Victor; Dirat, Béatrice; Dauvillier, Stéphanie; Bochet, Ludivine; Le Gonidec, Sophie; Escourrou, Ghislaine; Valet, Philippe; Muller, Catherine

2012-11-28

Among the many different cell types surrounding breast cancer cells, the most abundant are those that compose mammary adipose tissue, mainly mature adipocytes and progenitors. New accumulating recent evidences bring the tumor-surrounding adipose tissue into the light as a key component of breast cancer progression. The purpose of this review is to emphasize the role that adipose tissue might play by locally affecting breast cancer cell behavior and subsequent clinical consequences arising from this dialog. Two particular clinical aspects are addressed: obesity that was identified as an independent negative prognostic factor in breast cancer and the oncological safety of autologous fat transfer used in reconstructive surgery for breast cancer patients. This is preceded by the overall description of adipose tissue composition and function with special emphasis on the specificity of adipose depots and the species differences, key experimental aspects that need to be taken in account when cancer is considered. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Impact of single-walled carbon nanotubes on the embryo: a brief review

PubMed Central

Al Moustafa, Ala-Eddin; Mfoumou, Etienne; Roman, Dacian E; Nerguizian, Vahe; Alazzam, Anas; Stiharu, Ion; Yasmeen, Amber

2016-01-01

Carbon nanotubes (CNTs) are considered one of the most interesting materials in the 21st century due to their unique physiochemical characteristics and applicability to various industrial products and medical applications. However, in the last few years, questions have been raised regarding the potential toxicity of CNTs to humans and the environment; it is believed that the physiochemical characteristics of these materials are key determinants of CNT interaction with living cells and hence determine their toxicity in humans and other organisms as well as their embryos. Thus, several recent studies, including ours, pointed out that CNTs have cytotoxic effects on human and animal cells, which occur via the alteration of key regulator genes of cell proliferation, apoptosis, survival, cell–cell adhesion, and angiogenesis. Meanwhile, few investigations revealed that CNTs could also be harmful to the normal development of the embryo. In this review, we will discuss the toxic role of single-walled CNTs in the embryo, which was recently explored by several groups including ours. PMID:26855573

Mitochondria and Endothelial Function

PubMed Central

Kluge, Matthew A.; Fetterman, Jessica L.; Vita, Joseph A.

2013-01-01

In contrast to their role in other cell types with higher energy demands, mitochondria in endothelial cells primarily function in signaling cellular responses to environmental cues. This article provides an overview of key aspects of mitochondrial biology in endothelial cells, including subcellular location, biogenesis, dynamics, autophagy, ROS production and signaling, calcium homeostasis, regulated cell death, and heme biosynthesis. In each section, we introduce key concepts and then review studies showing the importance of that mechanism to endothelial control of vasomotor tone, angiogenesis, and inflammatory activation. We particularly highlight the small number of clinical and translational studies that have investigated each mechanism in human subjects. Finally, we review interventions that target different aspects of mitochondrial function and their effects on endothelial function. The ultimate goal of such research is the identification of new approaches for therapy. The reviewed studies make it clear that mitochondria are important in endothelial physiology and pathophysiology. A great deal of work will be needed, however, before mitochondria-directed therapies are available for the prevention and treatment of cardiovascular disease. PMID:23580773

Design and synthesis of emodin derivatives as novel inhibitors of ATP-citrate lyase.

PubMed

Koerner, Steffi K; Hanai, Jun-Ichi; Bai, Sha; Jernigan, Finith E; Oki, Miwa; Komaba, Chieko; Shuto, Emi; Sukhatme, Vikas P; Sun, Lijun

2017-01-27

Aberrant cellular metabolism drives cancer proliferation and metastasis. ATP citrate lyase (ACL) plays a critical role in generating cytosolic acetyl CoA, a key building block for de novo fatty acid and cholesterol biosynthesis. ACL is overexpressed in cancer cells, and siRNA knockdown of ACL limits cancer cell proliferation and reduces cancer stemness. We characterized a new class of ACL inhibitors bearing the key structural feature of the natural product emodin. Structure-activity relationship (SAR) study led to the identification of 1d as a potent lead that demonstrated dose-dependent inhibition of proliferation and cancer stemness of the A549 lung cancer cell line. Computational modeling indicates this class of inhibitors occupies an allosteric binding site and blocks the entrance of the substrate citrate to its binding site. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Interactions between Innate Immunity, Microbiota, and Probiotics

PubMed Central

Giorgetti, GianMarco; Brandimarte, Giovanni; Fabiocchi, Federica; Ricci, Salvatore; Flamini, Paolo; Sandri, Giancarlo; Trotta, Maria Cristina; Elisei, Walter; Penna, Antonio; Lecca, Piera Giuseppina; Picchio, Marcello

2015-01-01

The term “microbiota” means genetic inheritance associated with microbiota, which is about 100 times larger than the guest. The tolerance of the resident bacterial flora is an important key element of immune cell function. A key role in the interaction between the host and the microbiota is played by Paneth cell, which is able to synthesize and secrete proteins and antimicrobial peptides, such as α/β defensins, cathelicidin, 14 β-glycosidases, C-type lectins, and ribonuclease, in response to various stimuli. Recent studies found probiotics able to preserve intestinal homeostasis by downmodulating the immune response and inducing the development of T regulatory cells. Specific probiotic strain, as well as probiotic-driven metabolic products called “postbiotics,” has been recently recognized and it is able to influence innate immunity. New therapeutic approaches based on probiotics are now available, and further treatments based on postbiotics will come in the future. PMID:26090492

Hepatic Inflammation and Fibrosis: Functional Links and Key Pathways

PubMed Central

Seki, Ekihiro; Schwabe, Robert F.

2014-01-01

Inflammation is one of the most characteristic features of chronic liver disease of viral, alcoholic, fatty and autoimmune origin. Inflammation is typically present in all disease stages, and associated with the development of fibrosis, cirrhosis and hepatocellular carcinoma. In the past decade, numerous studies have contributed to improved understanding of the links between hepatic inflammation and fibrosis. Here, we review mechanisms that link inflammation with the development of liver fibrosis, focusing on the role of inflammatory mediators in hepatic stellate cell (HSC) activation and HSC survival during fibrogenesis and fibrosis regression. We will summarize the contributions of different inflammatory cells, including hepatic macrophages, T- and B-lymphocytes, NK cells and platelets, as well as key effectors such as cytokines, chemokines, and damage-associated molecular patterns. Furthermore, we will discuss the relevance of inflammatory signaling pathways for clinical liver disease and for the development of anti-fibrogenic strategies. PMID:25066777

Role of dynamin‐related protein 1‐mediated mitochondrial fission in resistance of mouse C2C12 myoblasts to heat injury

PubMed Central

Yu, Tianzheng; Deuster, Patricia

2016-01-01

Key points Understanding how skeletal muscles respond to high temperatures may help develop strategies for improving exercise tolerance and preventing heat injury.Mitochondria regulate cell survival by constantly changing their morphology through fusion and fission in response to environmental stimuli. Little is known about the involvement of mitochondrial dynamics in tolerance of skeletal muscle against heat stress.Mild heat acclimation and moderate heat shock appear to have different effects on the mitochondrial morphology and fission protein Drp1 in skeletal muscle cells. Mitochondrial integrity plays a key role in cell survival under heat stress. Abstract The regulation of mitochondrial morphology is closely coupled to cell survival during stress. We examined changes in the mitochondrial morphology of mouse C2C12 skeletal muscle cells in response to heat acclimation and heat shock exposure. Acclimated cells showed a greater survival rate during heat shock exposure than non‐acclimated cells, and were characterized by long interconnected mitochondria and reduced expression of dynamin‐related protein 1 (Drp1) for their mitochondrial fractions. Exposure of C2C12 muscle cells to heat shock led to apoptotic death featuring activation of caspase 3/7, release of cytochrome c and loss of cell membrane integrity. Heat shock also caused excessive mitochondrial fragmentation, loss of mitochondrial membrane potential and production of reactive oxygen species in C2C12 cells. Western blot and immunofluorescence image analysis revealed translocation of Drp1 to mitochondria from the cytosol in C2C12 cells exposed to heat shock. Mitochondrial division inhibitor 1 or Drp1 gene silencer reduced mitochondrial fragmentation and increased cell viability during exposure to heat shock. These results suggest that Drp1‐dependent mitochondrial fission may regulate susceptibility to heat‐induced apoptosis in muscle cells and that Drp1 may serve as a target for the prevention of heat‐related injury. PMID:27730652