NMR-based metabonomic analysis of the hepatotoxicity induced by combined exposure to PCBs and TCDD in rats

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

Lu Chunfeng; Department of Pharmacology, Basic Medical College, Jiamusi University, Jiamusi 154007; Wang Yimei

2010-11-01

A metabonomic approach using {sup 1}H NMR spectroscopy was adopted to investigate the metabonomic pattern of rat urine after oral administration of environmental endocrine disruptors (EDs) polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) alone or in combination and to explore the possible hepatotoxic mechanisms of combined exposure to PCBs and TCDD. {sup 1}H NMR spectra of urines collected 24 h before and after exposure were analyzed via pattern recognition by using principal component analysis (PCA). Serum biochemistry and liver histopathology indicated significant hepatotoxicity in the rats of the combined group. The PCA scores plots of urinary {sup 1}H NMR datamore » showed that all the treatment groups could be easily distinguished from the control group, so could the PCBs or TCDD group and the combined group. The loadings plots of the PCA revealed remarkable increases in the levels of lactate, glucose, taurine, creatine, and 2-hydroxy-isovaleric acid and reductions in the levels of 2-oxoglutarate, citrate, succinate, hippurate, and trimethylamine-N-oxide in rat urine after exposure. These changes were more striking in the combined group. The changed metabolites may be considered possible biomarker for the hepatotoxicity. The present study demonstrates that combined exposure to PCBs and TCDD induced significant hepatotoxicity in rats, and mitochondrial dysfunction and fatty acid metabolism perturbations might contribute to the hepatotoxicity. There was good conformity between changes in the urine metabonomic pattern and those in serum biochemistry and liver histopathology. These results showed that the NMR-based metabonomic approach may provide a promising technique for the evaluation of the combined toxicity of EDs.« less

TCDD alters medial epithelial cell differentiation during palatogenesis

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

Abbott, B.D.; Birnbaum, L.S.

1989-06-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widely distributed, persistent environmental contaminant that is teratogenic in mice, where it induces hydronephrosis and cleft palate. The incidence of clefting has been shown to be dose dependent after exposure on either gestation Day (GD) 10 or 12, although the embryo is more susceptible on GD 12. TCDD-exposed palatal shelves meet but do not fuse, and programmed cell death of the medial epithelial cells is inhibited. The mechanism of action through which TCDD alters the program of medial cell development has not been examined in earlier studies, and it is not known whether the mechanism ismore » the same regardless of the dose or developmental stage of exposure. In this study, C57BL/6N mice, a strain sensitive to TCDD, were dosed orally on GD 10 or 12 with 0, 6, 12, 24, or 30 micrograms/kg body wt, in 10 ml corn oil/kg. Embryonic palatal shelves were examined on GD 14, 15, or 16. The degree of palatal closure, epithelial surface morphology, and cellular ultrastructure, the incorporation of (3H)TdR, the expression of EGF receptors, and the binding of 125I-EGF were assessed. After exposure on GD 10 or 12, TCDD altered the differentiation pathway of the medial epithelial cells. The palatal shelves were of normal size and overall morphology, but fusion of the medial epithelia of the opposing shelves did not occur. TCDD prevented programmed cell death of the medial peridermal cells. The expression of EGF receptors by medial cells continued through Day 16 and the receptors were able to bind ligand. The medial cells differentiated into a stratified, squamous, keratinizing epithelium. The shift in phenotype to an oral-like epithelium occurred after exposure on either GD 10 or 12. At the lower dose (6 micrograms/kg), fewer cleft palates were produced, but those shelves which did respond had a fully expressed shift in differentiation.« less

TERATOGENIC RESPONSES OF TGFALPHA KNOCKOUT FETUSES TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

EPA Science Inventory

ABBOTT1, B.D., A.R. BUCKALEW1, and P.L. BRYANT2. 1Reproductive Toxicology Division, EPA, RAP, NC; 2Dept. Environ. Sciences & Engineering, UNC, Chapel Hill, NC. Teratogenic responses of TGF knockout fetuses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

TCDD induces cl...

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced cytotoxicity accompanied by oxidative stress in rat Sertoli cells: Possible role of mitochondrial fractions of Sertoli cells

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

Aly, Hamdy A.A., E-mail: hamdyaali@yahoo.com; Khafagy, Rasha M.

2011-05-01

TCDD, as an endocrine disruptor, is known to impair testicular functions and fertility. To elucidate the mechanism(s) underlying the testicular effects of TCDD, the potential toxicity of TCDD on Sertoli cells was investigated. Furthermore, the study aims to delineate whether mitochondrial fractions of Sertoli cells are involved in mediating the testicular effects of TCDD. Adult rat Sertoli cells were incubated with (5, 10 or 15 nM) of TCDD for 6, 12 or 24 h. Cell viability, lactate and LDH leakage into media along with lipid peroxidation, ROS generation, SOD, CAT, GPx, GR, {gamma}-GT and {beta}-glucuronidase activities, GSH content and {Delta}{psi}{submore » m} were measured. Superoxide anion production, COX and cardiolipin content were measured in mitochondrial fractions. Cell viability was significantly decreased while lactate and LDH leakage into media were increased. ROS generation along with lipid peroxidation was also increased. SOD, CAT, GPx, GR activities and GSH content were significantly decreased. {gamma}-GT and {beta}-glucuronidase activities were also decreased. Superoxide anion production was increased while COX activity and cardiolipin content were decreased in mitochondrial fractions. Moreover, the {Delta}{psi}{sub m} was significantly decreased as measured in Sertoli cells. In conclusion, TCDD impairs Sertoli cell functions and this effect is, at least in part, attributed to oxidative stress. We have also found that TCDD increases mitochondrial superoxide anion production and decreases {Delta}{psi}{sub m}, COX activity and mitochondrial cardiolipin content. Our findings suggest that mitochondria may play an important role in ROS production, leading to the TCDD-induced oxidative stress response and resulting toxicological consequences in rat Sertoli cells.« less

TCDD Inhibition of Canonical Wnt Signaling Disrupts Prostatic Bud Formation in Mouse Urogenital Sinus

PubMed Central

Peterson, Richard E.

2013-01-01

In mice, in utero exposure to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD) reduces the number of dorsolateral prostatic buds resulting in a smaller dorsolateral prostate and prevents formation of ventral buds culminating in ventral prostate agenesis. The genes and signaling pathways affected by TCDD that are responsible for disrupting prostate development are largely unknown. Here we show that treatment of urogenital sinus (UGS) organ cultures with known inhibitors of canonical Wnt signaling also inhibits prostatic bud formation. In support of the hypothesis that TCDD decreases canonical Wnt signaling, we identify inhibitory effects of TCDD on multiple components of the canonical Wnt signaling pathway in the UGS that temporally coincide with the inhibitory effect of TCDD on prostatic bud formation: (1) expression of R-spondins (Rspo2 and Rspo3) that promote canonical Wnt signaling is reduced; (2) expression of Lef1, Tcf1, and Wif1, established canonical Wnt target genes, is decreased; (3) expression of Lgr5, a RSPO receptor that activates canonical Wnt signaling, is reduced; and (4) expression of Dickkopfs (Dkks), inhibitors of canonical Wnt signaling, is not increased by TCDD. Thus, the TCDD-induced reduction in canonical Wnt signaling is associated with a decrease in activators (Rspo2 and Rspo3) rather than an increase in inhibitors (Dkk1 and Dkk2) of the pathway. This study focuses on determining whether treatment of TCDD-exposed UGS organ cultures with RSPO2 and/or RSPO3 is capable of rescuing the inhibitory effects of TCDD on canonical Wnt signaling and prostatic bud formation. We discovered that each RSPO alone or in combination partially rescues TCDD inhibition of both canonical Wnt signaling and prostatic bud formation. PMID:23429912

TCDD inhibition of canonical Wnt signaling disrupts prostatic bud formation in mouse urogenital sinus.

PubMed

Branam, Amanda M; Davis, Nicole M; Moore, Robert W; Schneider, Andrew J; Vezina, Chad M; Peterson, Richard E

2013-05-01

In mice, in utero exposure to 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD) reduces the number of dorsolateral prostatic buds resulting in a smaller dorsolateral prostate and prevents formation of ventral buds culminating in ventral prostate agenesis. The genes and signaling pathways affected by TCDD that are responsible for disrupting prostate development are largely unknown. Here we show that treatment of urogenital sinus (UGS) organ cultures with known inhibitors of canonical Wnt signaling also inhibits prostatic bud formation. In support of the hypothesis that TCDD decreases canonical Wnt signaling, we identify inhibitory effects of TCDD on multiple components of the canonical Wnt signaling pathway in the UGS that temporally coincide with the inhibitory effect of TCDD on prostatic bud formation: (1) expression of R-spondins (Rspo2 and Rspo3) that promote canonical Wnt signaling is reduced; (2) expression of Lef1, Tcf1, and Wif1, established canonical Wnt target genes, is decreased; (3) expression of Lgr5, a RSPO receptor that activates canonical Wnt signaling, is reduced; and (4) expression of Dickkopfs (Dkks), inhibitors of canonical Wnt signaling, is not increased by TCDD. Thus, the TCDD-induced reduction in canonical Wnt signaling is associated with a decrease in activators (Rspo2 and Rspo3) rather than an increase in inhibitors (Dkk1 and Dkk2) of the pathway. This study focuses on determining whether treatment of TCDD-exposed UGS organ cultures with RSPO2 and/or RSPO3 is capable of rescuing the inhibitory effects of TCDD on canonical Wnt signaling and prostatic bud formation. We discovered that each RSPO alone or in combination partially rescues TCDD inhibition of both canonical Wnt signaling and prostatic bud formation.

CHANGES IN EXPRESSION OF PHOSPHORYLATED AND TOTAL ERK 1/2 IN TCDD-EXPOSED EMBRYONIC MOUSE PALATES

EPA Science Inventory

CHANGES IN EXPRESSION OF PHOSPHORYLATED AND TOTAL ERK1/2 IN TCDD-EXPOSED EMBRYONIC MOUSE PALATES.
C Wolf and B Abbott, USEPA, ORD, NHEERL, Reproductive Toxicology Division, Research Triangle Park, NC 27711

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces cleft palate...

TCDD disrupts posterior palatogenesis and causes cleft palate.

PubMed

Yamada, Tomohiro; Hirata, Azumi; Sasabe, Eri; Yoshimura, Tomohide; Ohno, Seiji; Kitamura, Naoya; Yamamoto, Tetsuya

2014-01-01

Dioxins (e.g. 2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) cause cleft palate at a high rate. A post-fusional split may contribute to the pathogenesis, and tissue fragility may be a concern. The objective of this study was to investigate the effects of TCDD on the palatal epithelium, bone and muscle, which contribute to tissue integrity. ICR mice (10-12 weeks old) were used. TCDD was administered on E12.5 at 40 mg/kg. Immunohistochemical staining for AhR, ER-α, laminin, collagen IV, osteopontin, Runx2, MyoD, and desmin were performed. Furthermore, western blot analysis for osteopontin, Runx2, MyoD, and desmin were performed to evaluate protein expression in the palatal tissue. Immunohistologically, there was little difference in the collagen IV and laminin localization in the palatal epithelium between control versus TCDD-treated mice. Runx2 and osteopontin immunoreactivity decreased in the TCDD-treated palatal bone, and MyoD and desmin decreased in the TCDD-treated palatal muscle. AhR and ER-α immunoreactivity were localized to the normal palatal bone, but ER-α was diminished in the TCDD-treated palate. On western blot analysis, Runx2, MyoD, and desmin were all downregulated in the TCDD-treated palate. TCDD may suppress palatal osteogenesis and myogenesis via AhR, and cause cleft palates via a post-fusional split mechanism, in addition to a failure of palatal fusion. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

HYDRONEPHROSIS IN MICE EXPOSED TO TCDD-CONTAMINATED BREAST MILK: IDENTIFICATION OF THE PEAK PERIOD OF SENSITIVITY AND ASSESSMENT OF POTENTIAL RECOVERY

EPA Science Inventory

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent inducer of hydronephrosis in mice both pre- and post-natally. ritical period of sensitivity to TCDD could not be identified for the hydronephrotic response induced prenatally since the urinary tract appeared equally sensitive...

ANALYSIS OF 2,3,7,8-TCDD TUMOR PROMOTION ACTIVITY ...

EPA Pesticide Factsheets

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has a high estimated cancer potency in animals which has been reasoned to imply that TCDD might be carcinogenic to man. The animal cancer data show that TCDD can act in a solitary manner causing tumors without the participation of other known factors. owever, there exist animal cancer data indicating that TCDD can act as a tumor-promoting compound. This analysis examines which type of carcinogen and which mechanism best characterize TCDD cancer activity. It is suggested that TCDD acts by a hormonal mechanism to cause cancer in solitary manner, at low doses, in two species, and in a number of different organs, including rare sites. These observations in toto characterize TCDD as a complete carcinogen, which by definition encompasses both initiation and promotion carcinogenic activities. This analysis examines which type of carcinogen and which mechanism best characterize TCDD cancer activity. It is suggested that TCDD acts by a hormonal mechanism to cause cancer in solitary manner, at low doses, in two species, and in a number of different organs, including rare sites

Effects of selected food phytochemicals in reducing the toxic actions of TCDD and p,p′-DDT in U937 macrophages

PubMed Central

Sciullo, Eric M.; Vogel, Christoph F.; Wu, Dalei; Murakami, Akira; Ohigashi, Hajime

2010-01-01

To assess the effectiveness of selected food phytochemicals in reducing the toxic effects of the environmental toxicants, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and p,p′-DDT (DDT), we tested the potencies of auraptene, nobiletin, zerumbone, and (±)-13-hydroxy-10-oxo-trans-11-octadecenoic acid (13-HOA) in reversing the inflammatory action of these toxicants in U937 human macrophages. Using quantitative RT–PCR as the initial screening assay, we identified antagonistic actions of zerumbone and auraptene against the action of TCDD and DDT in up-regulating the mRNA expressions of COX-2 and VEGF. The functional significance of the inhibitory action of zerumbone on COX-2 expression was confirmed by demonstrating its suppression of TCDD-induced activation of COX-2 gene expression in mouse MMDD1 cells. We tested auraptene on DDT-induced reactive oxygen species (ROS) formation in U937 macrophages and found that auraptene is a powerful agent antagonizing this action of DDT. To confirm the significance of these actions of zerumbone and auraptene at the cellular level, we assessed their influence on TCDD-induced apoptosis resistance in intact U937 macrophages and found that they are capable of reversing this action of TCDD. In conclusion, zerumbone and auraptene were identified to be the most effective agents in protecting U937 macrophages from developing these cell toxic effects of TCDD and DDT. PMID:20865247

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and long term immunologic memory.

PubMed

Sherr, David H

2004-06-01

The highlighted article by B. Paige Lawrence and Beth Vorderstrasse addresses an oft forgotten aspect of immunotoxicity, the effects of environmental toxins on immunologic memory. Here, the authors take a step towards filling that information gap by evaluating the effects of a prototypic environmental toxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on memory responses to a real-world pathogen, influenza A virus, presented to an animal model in a physiologically relevant manner. Multiple outcomes are evaluated, the vast majority of which suggest important and long-term TCDD-induced changes in the immune system after both primary and secondary exposure to this pathogen. The implications of these studies with regard to the immuno-competence of TCDD-exposed individuals are far reaching.

Endocrine and metabolic aspects of the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

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

Gorski, J.R.

1988-01-01

Toxic responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were characterized in male Sprague-Dawley rats in order to elucidate the mechanism of acute toxicity of this potent halogenated hydrocarbon. Studies in TCDD-treated, pair-fed control and ad libitum-fed control rates, as well as in thyroidectomized, adrenalectomized and hypophysectomized, revealed differential hormonal, toxicologic and histophathologic responses suggesting that these manifestations of TCDD exposure are the results of an insult to intermediary metabolism. Tissue specific alterations in de novo fatty acid synthesis were directly related to differential changes observed in thyroid hormone homeostasis. The increased hepatic de novo fatty acid synthesis provided a likely mechanism for themore » documented fact that TCDD-treated rats lose more body weight than corresponding pair-fed controls because de novo fatty acid synthesis represents an energy inefficient metabolic process. Experiments in adrenalectomized and hypophysectomized rats led to the hypothesis that severe hypoglycemia due to inhibition of gluconeogenesis is the cause of TCDD-induced death. A subsequent characterization of gluconeogenesis in TCDD-treated rats confirmed this hypothesis.« less

TCDD, FICZ, and Other High Affinity AhR Ligands Dose-Dependently Determine the Fate of CD4+ T Cell Differentiation.

PubMed

Ehrlich, Allison K; Pennington, Jamie M; Bisson, William H; Kolluri, Siva K; Kerkvliet, Nancy I

2018-02-01

FICZ and TCDD, two high-affinity AhR ligands, are reported to have opposite effects on T cell differentiation with TCDD inducing regulatory T cells and FICZ inducing Th17 cells. This dichotomy has been attributed to ligand-intrinsic differences in AhR activation, although differences in sensitivity to metabolism complicate the issue. TCDD is resistant to AhR-induced metabolism and produces sustained AhR activation following a single dose in the μg/kg range, whereas FICZ is rapidly metabolized and AhR activation is transient. Nonetheless, prior studies comparing FICZ with TCDD have generally used the same 10-50 μg/kg dose range, and thus the two ligands would not equivalently activate AhR. We hypothesized that high-affinity AhR ligands can promote CD4+ T cell differentiation into both Th17 cells and Tregs, with fate depending on the extent and duration of AhR activation. We compared the immunosuppressive effects of TCDD and FICZ, along with two other rapidly metabolized ligands (ITE and 11-Cl-BBQ) in an acute alloresponse mouse model. The dose and timing of administration of each ligand was optimized for TCDD-equivalent Cyp1a1 induction. When optimized, all of the ligands suppressed the alloresponse in conjunction with the induction of Foxp3- Tr1 cells on day 2 and the expansion of natural Foxp3+ Tregs on day 10. In contrast, a low dose of FICZ induced transient expression of Cyp1a1 and did not induce Tregs or suppress the alloresponse but enhanced IL-17 production. Interestingly, low doses of the other ligands, including TCDD, also increased IL-17 production on day 10. These findings support the conclusion that the dose and the duration of AhR activation by high-affinity AhR ligands are the primary factors driving the fate of T cell differentiation. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Hepatic transcriptomic responses to TCDD in dioxin-sensitive and dioxin-resistant rats during the onset of toxicity

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

Boutros, Paul C.; Yao, Cindy Q.; Watson, John D.

2011-03-01

The dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a wide range of toxic effects in rodent species, all of which are mediated by a ligand-dependent transcription-factor, the aryl hydrocarbon receptor (AHR). The Han/Wistar (Kuopio) (H/W) strain shows exceptional resistance to many TCDD-induced toxicities; the LD{sub 50} of > 9600 {mu}g/kg for H/W rats is higher than for any other wild-type mammal known. We previously showed that this resistance primarily results from H/W rats expressing a variant AHR isoform that has a substantial portion of the AHR transactivation domain deleted. Despite this large deletion, H/W rats are not entirely refractory to the effectsmore » of TCDD; the variant AHR in these animals remains fully competent to up-regulate well-known dioxin-inducible genes. TCDD-sensitive (Long-Evans, L-E) and resistant (H/W) rats were treated with either corn-oil (with or without feed-restriction) or 100 {mu}g/kg TCDD for either four or ten days. Hepatic transcriptional profiling was done using microarrays, and was validated by RT-PCR analysis of 41 genes. A core set of genes was altered in both strains at all time points tested, including CYP1A1, CYP1A2, CYP1B1, Nqo1, Aldh3a1, Tiparp, Exoc3, and Inmt. Outside this core, the strains differed significantly in the breadth of response: three-fold more genes were altered in L-E than H/W rats. At ten days almost all expressed genes were dysregulated in L-E rats, likely reflecting emerging toxic responses. Far fewer genes were affected by feed-restriction, suggesting that only a minority of the TCDD-induced changes are secondary to the wasting syndrome.« less

COMPARING ENVIRONMENTALLY RELEVANT PCBS TO TCDD

EPA Science Inventory

COMPARING ENVIRONMENTALLY RELEVANT PCBS TO TCDD. D E Burgin1, J J Diliberto2 and L S Birnbaum3.1UNC, Chapel Hill, NC, USA; 2USEPA/ORD/NHEERL, ETD, RTP, NC, USA

Environmental exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) always occur as part of a complex mixture. ...

Mitochondrial damage elicits a TCDD-inducible poly(ADP-ribose) polymerase-mediated antiviral response

PubMed Central

Kozaki, Tatsuya; Komano, Jun; Kanbayashi, Daiki; Takahama, Michihiro; Misawa, Takuma; Satoh, Takashi; Takeuchi, Osamu; Kawai, Taro; Shimizu, Shigeomi; Matsuura, Yoshiharu; Akira, Shizuo; Saitoh, Tatsuya

2017-01-01

The innate immune system senses RNA viruses by pattern recognition receptors (PRRs) and protects the host from virus infection. PRRs mediate the production of immune modulatory factors and direct the elimination of RNA viruses. Here, we show a unique PRR that mediates antiviral response. Tetrachlorodibenzo-p-dioxin (TCDD)-inducible poly(ADP ribose) polymerase (TIPARP), a Cysteine3 Histidine (CCCH)-type zinc finger-containing protein, binds to Sindbis virus (SINV) RNA via its zinc finger domain and recruits an exosome to induce viral RNA degradation. TIPARP typically localizes in the nucleus, but it accumulates in the cytoplasm after SINV infection, allowing targeting of cytoplasmic SINV RNA. Redistribution of TIPARP is induced by reactive oxygen species (ROS)-dependent oxidization of the nuclear pore that affects cytoplasmic-nuclear transport. BCL2-associated X protein (BAX) and BCL2 antagonist/killer 1 (BAK1), B-cell leukemia/lymphoma 2 (BCL2) family members, mediate mitochondrial damage to generate ROS after SINV infection. Thus, TIPARP is a viral RNA-sensing PRR that mediates antiviral responses triggered by BAX- and BAK1-dependent mitochondrial damage. PMID:28213497

TCDD dysregulation of 13 AHR-target genes in rat liver

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

Watson, John D., E-mail: john.watson@oicr.on.ca; Prokopec, Stephenie D., E-mail: stephenie.prokopec@oicr.on.ca; Smith, Ashley B., E-mail: ashleyblaines@gmail.com

2014-02-01

Despite several decades of research, the complete mechanism by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other xenobiotic agonists of the aryl hydrocarbon receptor (AHR) cause toxicity remains unclear. While it has been shown that the AHR is required for all major manifestations of toxicity, the specific downstream changes involved in the development of toxic phenotypes remain unknown. Here we examine a panel of 13 genes that are AHR-regulated in many species and tissues. We profiled their hepatic mRNA abundances in two rat strains with very different sensitivities to TCDD: the TCDD-sensitive Long–Evans (Turku/AB; L–E) and the TCDD-resistant Han/Wistar (Kuopio; H/W). We evaluatedmore » doses ranging from 0 to 3000 μg/kg at 19 h after TCDD exposure and time points ranging from 1.5 to 384 h after exposure to 100 μg/kg TCDD. Twelve of 13 genes responded to TCDD in at least one strain, and seven of these showed statistically significant inter-strain differences in the time course analysis (Aldh3a1, Cyp1a2, Cyp1b1, Cyp2a1, Fmo1, Nfe2l2 and Nqo1). Cyp2s1 did not respond to TCDD in either rat strain. Five genes exhibited biphasic responses to TCDD insult (Ahrr, Aldh3a1, Cyp1b1, Nfe2l2 and Nqo1), suggesting a secondary event, such as association with additional transcriptional modulators. Of the 12 genes that responded to TCDD during the dose–response analysis, none had an ED{sub 50} equivalent to that of Cyp1a1, the most sensitive gene in this study, while nine genes responded to doses at least 10–100 fold higher, in at least one strain (Ahrr (L–E), Aldh3a1 (both), Cyp1a2 (both), Cyp1b1 (both), Cyp2a1 (L–E), Inmt (both), Nfe2l2 (L–E), Nqo1 (L–E) and Tiparp (both)). These data shed new light on the association of the AHR target genes with TCDD toxicity, and in particular the seven genes exhibiting strain-specific differences represent strong candidate mediators of Type-II toxicities. - Highlights: • NanoString measured hepatic m

TCDD influences reservoir of antibiotic resistance genes in murine gut microbiome.

PubMed

Stedtfeld, Robert D; Stedtfeld, Tiffany M; Fader, Kelly A; Williams, Maggie R; Bhaduri, Prianca; Quensen, John; Zacharewski, Timothy R; Tiedje, James M; Hashsham, Syed A

2017-05-01

Dysbiosis of the gut microbiome via antibiotics, changes in diet and infection can select for bacterial groups that more frequently harbor antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs). However, the impact of environmental toxicants on the reservoir of ARGs in the gut microbiome has received less attention. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent aryl hydrocarbon receptor (AhR) agonist with multiple toxic health effects including immune dysfunction. The selective pressure of TCDD on the abundance of ARG and MGE-harboring gut populations was examined using C57BL/6 mice exposed to 0-30 μg/kg TCDD for 28 and 92 days with the latter having a 30-day recovery period. DNA extracted from temporally collected fecal pellets was characterized using a qPCR array with 384 assays targeting ARGs and MGEs. Fourteen genes, typically observed in Enterobacteriaceae, increased significantly within 8 days of initial dosing, persisted throughout the treatment period, and remained induced 30 days post dosing. A qPCR primer set targeting Enterobacteriaceae also showed 10- to 100-fold higher abundance in TCDD-treated groups, which was further verified using metagenomics. Results show a bloom of ARG-harboring bacterial groups in the gut due to a xenobiotic compound that is not a metal, biocide or antimicrobial. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evaluation of TCDD biodegradability under different redox conditions.

PubMed

Kao, C M; Chen, S C; Liu, J K; Wu, M J

2001-09-01

Polychlorinated dibenzo-p-dioxins have been generated as unwanted by-products in many industrial processes. Although their widespread distribution in different environmental compartments has been recognized, little is known about their fate in the ultimate environment sinks. The highly stable dioxin isomer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been called the most toxic compound known to man. In this laboratory microcosm study, TCDD bioavailability was evaluated under five reduction/oxidation (redox) conditions including aerobic biodegradation, aerobic cometabolism, methanogenesis, iron reduction, and reductive dechlorination. Activated sludge and aquifer sediments from a TCDD and a pentachlorophenol (PCP) contaminated site were used as the inocula. Acetate, sludge cake, and cane molasses were used as the primary substrates (carbon sources) in cometabolism and reductive dechlorination microcosms. After a 90-day incubation period, microcosms constructed under reductive dechlorination conditions were the only treatment showing promising remediation results. The highest TCDD degradation rate [up to 86% of TCDD removal (with an initial concentration of 96 microg/kg of soil)] was observed in the microcosms with anaerobic activated sludge as the microbial inocula and sludge cakes as the primary substrates. Except for reductive dechlorination microcosms, no significant TCDD removal was observed in the microcosms prepared under other conditions. Thus, application of an effective primary substrate to enhance the reductive dechlorination process is a feasible method for TCDD bioremediation. Bioremediation expense can be significantly reduced by the supplement of some less expensive alternative substrates (e.g., sludge cakes, cane molasses). Results would be useful in designing a scale-up in situ or on-site bioremediation system such as bioslurry reactor for field application.

Differential susceptibilities of Holtzman and Sprague-Dawley rats to fetal death and placental dysfunction induced by 2,3,7,8-teterachlorodibenzo-p-dioxin (TCDD) despite the identical primary structure of the aryl hydrocarbon receptor

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

Kawakami, Takashige; Department of Hygiene-Chemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510; Ishimura, Ryuta

2006-05-01

A single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioin (TCDD) administered to pregnant Holtzman (HLZ) rats on gestational days 15 (GD15) caused placental dysfunction, resulting in fetal death (Ishimura, R., Ohsako, S., Miyabara, Y., Sakaue, M., Kawakami, T., Aoki, Y., Yonemoto, J., Tohyama, C., 2002a. Increased glycogen content and glucose transporter 3 mRNA level in the placenta of Holtzman rats after exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol. Appl. Pharmacol. 178, 161-171; Ishimura, R., Ohsako, S., Kawakami, T., Sakaue, M., Aoki, Y., Tohyama, C., 2002b. Altered protein profile and possible hypoxia in the placenta of 2,3,7,8-tetrachlorodibenzo-p-dioxin-exposed rats. Toxicol. Appl. Pharmacol. 185, 197-206). In order to investigatemore » the mechanism underlying the TCDD-induced fetal death, we compared two outbred strains of rats, namely, the HLZ and the Sprague-Dawley International Genetic Standard rats (SD-IGS), a strain with characteristics resembling those of the HLZ rats. Pregnant HLZ and SD-IGS rats were administered TCDD as a single dose by gavage on GD15, as described within the parentheses (HLZ, 0, 1.6 {mu}g TCDD/kg; SD-IGS, 0, 2, 5, 10 {mu}g TCDD/kg). Whereas a high incidence (14%) of fetal death was observed on GD20 in the HLZ rats, no fetal deaths occurred in the SD-IGS rats, even at the highest dose of TCDD. A histological marker of cellular abnormality at the placental junctional zone, i.e., delay in the disappearance of the glycogen cells and cysts filled with an eosinophilic material (GC-EM), which normally disappear by GD20, was observed in the HLZ rats after exposure to the lowest dose of TCDD (1.6 {mu}g TCDD/kg), but not in the SD-IGS rats even after exposure to the highest dose of TCDD. Furthermore, maternal blood sinusoids in the labyrinth zone were constricted following exposure to TCDD in the HLZ, but not SD-IGS rats. These observations indicate that HLZ rats are more susceptible to the adverse effects of TCDD on fetal

New insights to the role of aryl hydrocarbon receptor in bone phenotype and in dioxin-induced modulation of bone microarchitecture and material properties

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

Herlin, Maria, E-mail: maria.herlin@ki.se; Finnilä, Mikko A.J., E-mail: mikko.finnila@oulu.fi; Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu

Bone is a target for high affinity aryl hydrocarbon receptor (AHR) ligands, such as dioxins. Although bone morphology, mineral density and strength are sensitive endpoints of dioxin toxicity, less is known about effects on bone microarchitecture and material properties. This study characterizes TCDD-induced modulations of bone tissue, and the role of AHR in dioxin-induced bone toxicity and for normal bone phenotype. Six AHR-knockout (Ahr{sup −/−}) and wild-type (Ahr{sup +/+}) mice of both genders were exposed to TCDD weekly for 10 weeks, at a total dose of 200 μg/kg bw. Bones were examined with micro-computed tomography, nanoindentation and biomechanical testing. Serummore » levels of bone remodeling markers were analyzed, and the expression of genes related to osteogenic differentiation was profiled using PCR array. In Ahr{sup +/+} mice, TCDD-exposure resulted in harder bone matrix, thinner and more porous cortical bone, and a more compact trabecular bone compartment. Bone remodeling markers and altered expression of a number of osteogenesis related genes indicated imbalanced bone remodeling. Untreated Ahr{sup −/−} mice displayed a slightly modified bone phenotype as compared with untreated Ahr{sup +/+} mice, while TCDD exposure caused only a few changes in bones of Ahr{sup −/−} mice. Part of the effects of both TCDD-exposure and AHR-deficiency were gender dependent. In conclusion, exposure of adult mice to TCDD resulted in harder bone matrix, thinner cortical bone, mechanically weaker bones and most notably, increased trabecular bone volume fraction in Ahr{sup +/+} mice. AHR is involved in bone development of a normal bone phenotype, and is crucial for manifestation of TCDD-induced bone alterations. - Highlights: • TCDD disrupts bone remodeling resulting in altered cortical and trabecular bone. • In trabecular bone an anabolic effect is observed. • Cortical bone is thinner, more porous, harder, stiffer and mechanically weaker. • AHR

TCDD AND EGF AFFECT MAPK PATHWAY ACTIVATION IN MURINE EMBRYONIC PALATE

EPA Science Inventory

Palatal fusion occurs on GD 14-15 in the mouse, accompanied by a decrease in EGF receptor (EGFR) at the medial edge of the palatal shelves. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces cleft palate and maintains EGF and EGF receptor (EGFR) expression levels in the medial ed...

COMPARISONS OF THE EFFECTS OF TCDD AND HYDROCORTISONE (HC) ON GROWTH FACTOR EXPRESSION PROVIDE INSIGHT INTO THE SYNERGISTIC INTERACTION OCCURRING IN EMBRYONIC PALATES

EPA Science Inventory

Cleft palate (CP) can be Induced In embryonic mice by a Wide range of compounds, including glucocorticoids and 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD). ydrocortisone (HC), a glucocorticoid, retards embryonic growth producing small palatal shelves, while TCDD exposure blocks t...

An enhanced postnatal autoimmune profile in 24 week-old C57BL/6 mice developmentally exposed to TCDD

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

Mustafa, A.; Holladay, S.D.; Goff, M.

Developmental exposure of mice to the environmental contaminant and AhR agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), causes persistent postnatal suppression of T cell-mediated immune responses. The extent to which prenatal TCDD may induce or exacerbate postnatal autoimmune disease remains unknown. In the present study, time-pregnant high affinity AhR C57BL/6 mice received a single oral administration of 0, 2.5, or 5 {mu}g/kg TCDD on gestation day (gd) 12. Offspring of these mice (n = 5/gender/treatment) were evaluated at 24 weeks-of-age and showed considerable immune dysregulation that was often gender-specific. Decreased thymic weight and percentages of CD4{sup +}CD8{sup +} thymocytes, and increased CD4{sup +}CD8{sup -}more » thymocytes, were present in the female but not male offspring. Males but not females showed decreased CD4{sup -}CD8{sup +} T cells, and increased V{beta}3{sup +} and V{beta}17a{sup +} T cells, in the spleen. Males but not females also showed increased percentages of bone marrow CD24{sup -}B220{sup +} B cell progenitors. Antibody titers to dsDNA, ssDNA and cardiolipin displayed increasing trends in both male and female mice, reaching significance for anti-dsDNA in both genders and for ssDNA in males at 5 {mu}g/kg TCDD. Immunofluorescent staining of IgG and C3 deposition in kidney glomeruli increased in both genders of prenatal TCDD-exposed mice, suggestive of early stages of autoimmune glomerulonephritis. Collectively, these results show that exposure to TCDD during immune system development causes persistent humoral immune dysregulation as well as altered cell-mediated responses, and induces an adult profile of changes suggestive of increased risk for autoimmune disease.« less

USE OF A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL (PBPK) FOR RATS TO STUDY THE INFLUENCE OF BODY FAT MASS AND INDUCTION OF CYP1A2 ON THE PHARMACOKINETICS OF TCDD

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly lipophilic chemical which distributes into adipose tissue, especially at low doses. However, at high doses TCDD sequesters in liver because it induces CYP1A2 that binds TCDD. A physiologically based pharmacokinetic (PBPK) mod...

Comparison of mathematically-predicted toxic equivalents (TEQs) and bioassay-derived dioxin-equivalents (TCDD-EQs) in heron embryos

USGS Publications Warehouse

Rattner, B.; Hatfield, J.; Melancon, M.; Custer, T.; Tillitt, D.

1995-01-01

Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from an uncontaminated site (Chincoteague National Wildlife Refuge,VA) and three polluted sites (Cat Island, Green Bay, WI; Bair and West Marin Islands, San Francisco Bay, CA). Hepatic microsomal monooxygenases were induced up to 85-fold relative to the reference site, and was associated with concentrations of total PCBs and 11 PCB congeners that are presumed to concern.to express toxicity through the Ah receptor. TEQs [mathematically predicted; summed product of PCB congener concentrations using 5 different sets of toxic equivalency factors (TEFs)] were compared to TCDD-EQs [derived by bioassay; ethoxyresorufin-O-dealkylase activity of treated H411E rat hepatoma cells]. Although TEQs were up to 15-fold greater than TCDD-EQs, the pattern among sites was consistent and TEQs were highly correlated with TCDD-EQs. TEFs based on single congener mammalian studies yielded TEQs that greatly exceeded values from the H411E bioassay of field sample. TEFs generated from avian egg injection studies yielded TEQs that most closely approximated bioassay-derived TCDD-EQs. Cytochrome P450 parameters were related to TEQs and TCDD-EQs; adjusted r2 often exceeded 0.5 for the relation among mathematically predicted TEQs and cytochrome P450 measurements. These data document the general predictive value of TEQs and TCDD-EQs for P450 induction in field collected samples, but also indicate the need for development of TEFs for the species and biological end point of concern.

Hydronephrosis in mice exposed to TCDD-contaminated breast milk: Identification of the peak period of sensitivity and assessment of potential recovery

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

Couture-Haws, L.; Harris, M.W.; McDonald, M.M.

1991-01-01

2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent inducer of hydronephrosis in mice both pre- and post-natally. To identify the critical period of susceptibility for development of TCDD-induced hydronephrosis in neonatal mice, as well as to characterize the potential for recovery from this renal lesion, dose-response and time-course studies were conducted using lactational exposure. Pregnant C57BL/6N mice were allowed natural delivery. In the dose-response phase of the investigation, mothers were administered 0, 3, 6, or 12 microgram TCDD/kg once by gavage on post natal day (pnd) 1, 4, 8, or 14, and dams and pups were sacrificed on pnd 26.more » In the time-course studies, dams were given a single oral dose of 0 or 9 microgram TCDD/kg on pnd 1, and mothers and litters were subsequently sacrificed on pnd 7, 13, 19, or 26. Neonatal kidneys were examined, and hydronephrotic severity was scored. The incidence and severity of hydronephrosis were significantly elevated above controls at all dose levels on pnd 26 following treatment on pnds 1 and 4, while treatment on pnd 8 or 14 was ineffective at inducing hydronephrosis.« less

2,3,7,8-TCDD effects on visual structure and function in swim-up rainbow trout

USGS Publications Warehouse

Carvalho, Paulo S. M.

2004-01-01

An understanding of mechanisms of contaminant effects across levels of biological organization is essential in ecotoxicology if we are to generate predictive models for population-level effects. We applied a suite of biochemical, histological, and behavioral end points related to visual structure and function and foraging behavior to evaluate effects of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) on swim-up rainbow trout. We detected a dose-dependent decrease in densities of retinal ganglion cells (RGC), key retinal neurons that link the eye with the brain. These changes resulted in corresponding deficits in visual/motor function including reductions in visual acuity and in scotopic and photopic thresholds due to TCDD. The loss of RGCs suggests an increase in convergence of synapses from photoreceptors to RGCs as a cellular mechanism for the visual deficits. Dose-dependent increases in immunohistochemical detection of CYP1A protein in the vasculature of the brain and eye choroid was proportional with decreased ganglion cell densities in the retina. TCDD-induced AHR-regulated effects on these tissues might be involved in the detected decrease in ganglion cell densities. Prey capture rate decreased after TCDD exposure only at the highest treatment groups evaluated. Collectively, these results show that TCDD causes biochemical and structural changes in the eye and brain of rainbow trout that are associated with behavioral deficits leading to decreased individual fitness.

Severe 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) intoxication: kinetics and trials to enhance elimination in two patients.

PubMed

Geusau, Alexandra; Schmaldienst, Sabine; Derfler, Kurt; Päpke, Olaf; Abraham, Klaus

2002-06-01

In spring 1998, two women were diagnosed with severe 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) intoxication. Over the following 3 years, TCDD levels were monitored under various attempts to enhance its elimination, and the half-lives were evaluated. Olestra, a non-digestible, non-absorbable dietary fat substitute, was continuously administered to the patients either as pure substance or in potato-chips. Additionally, in the more severely contaminated patient, we studied whether low-density lipoprotein (LDL)-apheresis, an extracorporeal means of blood lipid elimination, was effective in reducing the TCDD body burden. The blood concentrations initially measured in spring 1998 were 144,000 pg/g blood fat in patient 1 and 26,000 pg/g in patient 2, the highest levels ever measured in adults. In March 2001, concentrations in blood fat were 35,900 and 9,500 pg/g, corresponding to overall elimination half-lives of 560 days (1.5 years) in patient 1 and 1050 days (2.9 years) in patient 2, which are considerably shorter than median values of 7-9 years reported for background and moderate exposure levels. Calculations of the TCDD half-lives and measurements of TCDD elimination via different routes allowed the calculation of an unidentified route of elimination, representing 78 and 62% of the overall elimination in patient 1 and 2, respectively, probably due to an induced hepatic metabolism caused by the high TCDD exposure. As previously reported, administration of olestra was found to be effective in increasing the fecal excretion of TCDD. Due to the short half-lives in our patients, the effect of olestra on the overall elimination was relatively small, but is expected to be much greater for 'normal' half-lives. LDL-apheresis was shown to eliminate TCDD, corresponding to the eliminated blood fat. When employed twice a week, the amount of TCDD excreted by this method was comparable to fecal excretion. In view of costs and time involved, LDL-apheresis does not seem to be

Comparison of hepatic NRF2 and AHR binding in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treated mice demonstrates NRF2-independent PKM2 induction.

PubMed

Nault, Rance; Doskey, Claire M; Fader, Kelly A; Rockwell, Cheryl E; Zacharewski, Timothy R

2018-05-11

2,3,7,8-Tetrachlorodibenzo- p -dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies showed TCDD induced pyruvate kinase muscle isoform 2 ( Pkm2 ) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 ( Nrf2 ) and the AhR in the induction of Pkm2 , hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h after TCDD treatment identified genome-wide NRF2 enrichment. Approximately 842 NRF2 enriched regions were located in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis of regions with overlapping NRF2 and AhR enrichment showed over-representation of either antioxidant or dioxin response elements (ARE and DRE, respectively), although 18 possessed both motifs. NRF2 exhibited negligible enrichment within a closed Pkm chromatin region while the AhR was enriched 29-fold. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate to regulate numerous antioxidant gene expression responses, the induction of Pkm2 by TCDD is independent of ROS-mediated NRF2 activation. The American Society for Pharmacology and Experimental Therapeutics.

ROLES OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF-A) IN MEDIATION OF DIOXIN (TCDD)-INDUCED DELAYS IN DEVELOPMENT OF THE MOUSE MAMMARY GLAND

EPA Science Inventory

Roles of Epidermal Growth Factor (EGF) and Transforming Growth Factor-alpha (TGF-a) in Mediation of Dioxin (TCDD)-Induced Delays in Development of the Mouse Mammary Gland.
Suzanne E. Fenton, Barbara Abbott, Lamont Bryant, and Angela Buckalew. U.S. EPA, NHEERL, Reproductive Tox...

Malformation of certain brain blood vessels caused by TCDD activation of Ahr2/Arnt1 signaling in developing zebrafish.

PubMed

Teraoka, Hiroki; Ogawa, Akira; Kubota, Akira; Stegeman, John J; Peterson, Richard E; Hiraga, Takeo

2010-08-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). The AHR also plays important roles in normal development in mice, and AHR(-/-) mice show abnormal development of vascular structures in various blood vessels. Our previous studies revealed that Ahr type 2 (Ahr2) activation by TCDD and beta-naphthoflavone (BNF) caused a significant decrease in blood flow in the dorsal midbrain of zebrafish embryos. Here we report effects of TCDD exposure on the morphology of some blood vessels in the head of developing zebrafish. TCDD caused concentration-dependent anatomical rearrangements in the shape of the prosencephalic artery in zebrafish larvae. In contrast, no major vascular defects were recognized in the trunk and tail regions following exposure to TCDD at least at the concentrations used. Essentially, the same observations were also confirmed in BNF-exposed larvae. Knock-down of either Ahr2 or Ahr nuclear translocator type 1 (Arnt1) by morpholino oligonucleotides (MOs) protected larvae against abnormal shape of the prosencephalic artery caused by TCDD and BNF. On the other hand, knock-down of Ahr2 or Arnt1 in vehicle-exposed zebrafish larvae had no clear effect on morphology of the prosencephalic artery or trunk vessels. Ascorbic acid, an antioxidant, protected against the TCDD-induced decrease in blood flow through the prosencephalic artery, but not the abnormal morphological changes in the shape of this artery. These results indicate that activation of Ahr2/Arnt1 pathway by TCDD and BNF affects the shape of certain blood vessels in the brain of developing zebrafish. (c) 2010 Elsevier B.V. All rights reserved.

A critical review of the epidemiology of Agent Orange/TCDD and prostate cancer.

PubMed

Chang, Ellen T; Boffetta, Paolo; Adami, Hans-Olov; Cole, Philip; Mandel, Jack S

2014-10-01

To inform risk assessment and regulatory decision-making, the relationship between 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and prostate cancer requires clarification. This article systematically and critically reviews the epidemiologic evidence on the association between exposure to TCDD or Agent Orange, a TCDD-contaminated herbicide used during the Vietnam War, and prostate cancer risk. Articles evaluated include 11 studies of three cohorts, four case-control or cross-sectional studies, and three case-only studies of military veterans with information on estimated Agent Orange or TCDD exposure; 13 studies of seven cohorts, one case-control study, and eight proportionate morbidity or mortality studies of Vietnam veterans without information on Agent Orange exposure; 11 cohort studies of workers with occupational exposure to TCDD; and two studies of one community cohort with environmental exposure to TCDD. The most informative studies, including those of Vietnam veterans involved in Agent Orange spraying or other handling, herbicide manufacturing or spraying workers with occupational TCDD exposure, and community members exposed to TCDD through an industrial accident, consistently reported no significant increase in prostate cancer incidence or mortality. Only some potentially confounded studies of Vietnam veterans compared with the general population, studies with unreliable estimates of Agent Orange exposure, and analyses of selected subgroups of Vietnam veterans reported positive associations. Overall, epidemiologic research offers no consistent or convincing evidence of a causal relationship between exposure to Agent Orange or TCDD and prostate cancer. More accurate exposure assessment is needed in large epidemiologic studies to rule out a causal association more conclusively.

Sox9b Is Required for Epicardium Formation and Plays a Role in TCDD-Induced Heart Malformation in Zebrafish

PubMed Central

Hofsteen, Peter; Plavicki, Jessica; Johnson, Shaina D.; Peterson, Richard E.

2013-01-01

Activation of the transcription factor aryl hydrocarbon receptor by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) prevents the formation of the epicardium and leads to severe heart malformations in developing zebrafish (Danio rerio). The downstream genes that cause heart malformation are not known. Because TCDD causes craniofacial malformations in zebrafish by downregulating the sox9b gene, we hypothesized that cardiotoxicity might also result from sox9b downregulation. We found that sox9b is expressed in the developing zebrafish heart ventricle and that TCDD exposure markedly reduces this expression. Furthermore, we found that manipulation of sox9b expression could phenocopy many but not all of the effects of TCDD at the heart. Loss of sox9b prevented the formation of epicardium progenitors comprising the proepicardium on the pericardial wall, and prevented the formation and migration of the epicardial layer around the heart. Zebrafish lacking sox9b showed pericardial edema, an elongated heart, and reduced blood circulation. Fish lacking sox9b failed to form valve cushions and leaflets. Sox9b is one of two mammalian Sox9 homologs, sox9b and sox9a. Knock down of sox9a expression did not cause cardiac malformations, or defects in epicardium development. We conclude that the decrease in sox9b expression in the heart caused by TCDD plays a role in many of the observed signs of cardiotoxicity. We find that while sox9b is expressed in myocardial cells, it is not normally expressed in the affected epicardial cells or progenitors. We therefore speculate that sox9b is involved in signals between the cardiomyocytes and the nascent epicardial cells. PMID:23775563

TCDD and a putative endogenous AhR ligand, ITE, elicit the same immediate changes in gene expression in mouse lung fibroblasts.

PubMed

Henry, Ellen C; Welle, Stephen L; Gasiewicz, Thomas A

2010-03-01

The aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, mediates toxicity of several classes of xenobiotics and also has important physiological roles in differentiation, reproduction, and immunity, although the endogenous ligand(s) mediating these functions is/are as yet unidentified. One candidate endogenous ligand, 2-(1'H-indolo-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), is a potent AhR agonist in vitro, activates the murine AhR in vivo, but does not induce toxicity. We hypothesized that ITE and the toxic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may modify transcription of different sets of genes to account for their different toxicity. To test this hypothesis, primary mouse lung fibroblasts were exposed to 0.5muM ITE, 0.2nM TCDD, or vehicle for 4 h, and total gene expression was evaluated using microarrays. After this short-term and low-dose treatment, several hundred genes were changed significantly, and the response to ITE and TCDD was remarkably similar, both qualitatively and quantitatively. Induced gene sets included the expected battery of AhR-dependent xenobiotic-metabolizing enzymes, as well as several sets that reflect the inflammatory role of lung fibroblasts. Real time quantitative RT-qPCR assay of several selected genes confirmed these microarray data and further suggested that there may be kinetic differences in expression between ligands. These data suggest that ITE and TCDD elicit an analogous change in AhR conformation such that the initial transcription response is the same. Furthermore, if the difference in toxicity between TCDD and ITE is mediated by differences in gene expression, then it is likely that secondary changes enabled by the persistent TCDD, but not by the shorter lived ITE, are responsible.

TCDD and a Putative Endogenous AhR Ligand, ITE, Elicit the Same Immediate Changes in Gene Expression in Mouse Lung Fibroblasts

PubMed Central

Henry, Ellen C.; Welle, Stephen L.; Gasiewicz, Thomas A.

2010-01-01

The aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, mediates toxicity of several classes of xenobiotics and also has important physiological roles in differentiation, reproduction, and immunity, although the endogenous ligand(s) mediating these functions is/are as yet unidentified. One candidate endogenous ligand, 2-(1′H-indolo-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), is a potent AhR agonist in vitro, activates the murine AhR in vivo, but does not induce toxicity. We hypothesized that ITE and the toxic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may modify transcription of different sets of genes to account for their different toxicity. To test this hypothesis, primary mouse lung fibroblasts were exposed to 0.5μM ITE, 0.2nM TCDD, or vehicle for 4 h, and total gene expression was evaluated using microarrays. After this short-term and low-dose treatment, several hundred genes were changed significantly, and the response to ITE and TCDD was remarkably similar, both qualitatively and quantitatively. Induced gene sets included the expected battery of AhR-dependent xenobiotic-metabolizing enzymes, as well as several sets that reflect the inflammatory role of lung fibroblasts. Real time quantitative RT-qPCR assay of several selected genes confirmed these microarray data and further suggested that there may be kinetic differences in expression between ligands. These data suggest that ITE and TCDD elicit an analogous change in AhR conformation such that the initial transcription response is the same. Furthermore, if the difference in toxicity between TCDD and ITE is mediated by differences in gene expression, then it is likely that secondary changes enabled by the persistent TCDD, but not by the shorter lived ITE, are responsible. PMID:19933214

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters the endogenous metabolism of all-trans-retinoic acid in the rat.

PubMed

Schmidt, Carsten K; Hoegberg, Pi; Fletcher, Nicholas; Nilsson, Charlotte B; Trossvik, Christina; Håkansson, Helen; Nau, Heinz

2003-07-01

2,3,7,8-Tetrachlorodibenzo- p-dioxin (TCDD) is known to influence vitamin A homeostasis. In order to investigate the mechanism behind this retinoid disruption, male Sprague-Dawley rats were exposed to TCDD at doses ranging from 0.1 to 100 micro g/kg body weight, and were killed 3 days after exposure. Additional groups of rats were killed 1 and 28 days after a single oral dose of 10 micro g TCDD/kg body weight. Serum, kidney, and liver were investigated for retinoid levels, as well as gene expression and enzyme activities relevant for retinoid metabolism. Besides the well known effects of TCDD on apolar retinoids, i.e. decreased hepatic and increased renal retinyl ester (RE) levels, we have found dose-dependent elevation of all- trans-retinoic acid (all- trans-RA) levels in all investigated tissues. In the liver, 9- cis-4-oxo-13,14-dihydro-RA was drastically decreased by TCDD in a dose-dependent manner. In serum, cis-isomers of all- trans-RA, including 9,13-di- cis-RA, were significantly reduced already at the lowest dose level. Protein and mRNA levels of cellular retinol binding protein I (CRBP-I) in liver or kidneys were not significantly altered by TCDD exposure at doses at which retinoid levels were affected, making CRBP-I an unlikely candidate to account for the alterations in retinoid metabolism caused by TCDD. The expression and activities of relevant cytochrome P450 (CYP) enzymes with potential roles in all- trans-RA synthesis and/or degradation (CYP1A1, 1A2, and 2B1/2) were also monitored. A possible role of CYP1A1 in TCDD-induced all- trans-RA synthesis is suggested from the time-course relationship between CYP1A1 activity and all- trans-RA levels in liver and kidney. The significant alteration of the all- trans-RA metabolism has the potential to contribute significantly to the toxicity of TCDD.

ITE and TCDD differentially regulate the vascular remodeling of rat placenta via the activation of AhR.

PubMed

Wu, Yanming; Chen, Xiao; Zhou, Qian; He, Qizhi; Kang, Jiuhong; Zheng, Jing; Wang, Kai; Duan, Tao

2014-01-01

Vascular remodeling in the placenta is essential for normal fetal development. The previous studies have demonstrated that in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an environmental toxicant) induces the intrauterine fetal death in many species via the activation of aryl hydrocarbon receptor (AhR). In the current study, we compared the effects of 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) and TCDD on the vascular remodeling of rat placentas. Pregnant rats on gestational day (GD) 15 were randomly assigned into 5 groups, and were exposed to a single dose of 1.6 and 8.0 mg/kg body weight (bw) ITE, 1.6 and 8.0 µg/kg bw TCDD, or an equivalent volume of the vehicle, respectively. The dams were sacrificed on GD20 and the placental tissues were gathered. The intrauterine fetal death was observed only in 8.0 µg/kg bw TCDD-exposed group and no significant difference was seen in either the placental weight or the fetal weight among all these groups. The immunohistochemical and histological analyses revealed that as compared with the vehicle-control, TCDD, but not ITE, suppressed the placental vascular remodeling, including reduced the ratio of the placental labyrinth zone to the basal zone thickness (at least 0.71 fold of control), inhibited the maternal sinusoids dilation and thickened the trophoblastic septa. However, no marked difference was observed in the density of fetal capillaries in the labyrinth zone among these groups, although significant differences were detected in the expression of angiogenic growth factors between ITE and TCDD-exposed groups, especially Angiopoietin-2 (Ang-2), Endoglin, Interferon-γ (IFN-γ) and placenta growth factor (PIGF). These results suggest ITE and TCDD differentially regulate the vascular remodeling of rat placentas, as well as the expression of angiogenic factors and their receptors, which in turn may alter the blood flow in the late gestation and partially resulted in

ITE and TCDD Differentially Regulate the Vascular Remodeling of Rat Placenta via the Activation of AhR

PubMed Central

Zhou, Qian; He, Qizhi; Kang, Jiuhong; Zheng, Jing; Wang, Kai; Duan, Tao

2014-01-01

Vascular remodeling in the placenta is essential for normal fetal development. The previous studies have demonstrated that in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an environmental toxicant) induces the intrauterine fetal death in many species via the activation of aryl hydrocarbon receptor (AhR). In the current study, we compared the effects of 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) and TCDD on the vascular remodeling of rat placentas. Pregnant rats on gestational day (GD) 15 were randomly assigned into 5 groups, and were exposed to a single dose of 1.6 and 8.0 mg/kg body weight (bw) ITE, 1.6 and 8.0 µg/kg bw TCDD, or an equivalent volume of the vehicle, respectively. The dams were sacrificed on GD20 and the placental tissues were gathered. The intrauterine fetal death was observed only in 8.0 µg/kg bw TCDD-exposed group and no significant difference was seen in either the placental weight or the fetal weight among all these groups. The immunohistochemical and histological analyses revealed that as compared with the vehicle-control, TCDD, but not ITE, suppressed the placental vascular remodeling, including reduced the ratio of the placental labyrinth zone to the basal zone thickness (at least 0.71 fold of control), inhibited the maternal sinusoids dilation and thickened the trophoblastic septa. However, no marked difference was observed in the density of fetal capillaries in the labyrinth zone among these groups, although significant differences were detected in the expression of angiogenic growth factors between ITE and TCDD-exposed groups, especially Angiopoietin-2 (Ang-2), Endoglin, Interferon-γ (IFN-γ) and placenta growth factor (PIGF). These results suggest ITE and TCDD differentially regulate the vascular remodeling of rat placentas, as well as the expression of angiogenic factors and their receptors, which in turn may alter the blood flow in the late gestation and partially resulted in

Plasma Cytokine Concentrations in Workers Exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

PubMed Central

Saberi Hosnijeh, Fatemeh; Boers, Daisy; Portengen, Lützen; Bueno-de-Mesquita, H. Bas; Heederik, Dick; Vermeulen, Roel

2012-01-01

Objectives: Few epidemiological studies have studied the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on blood cytokine levels. In this study we investigated changes in plasma levels of a large panel of cytokines, chemokines, and growth factors among workers from a Dutch historical cohort occupationally exposed to chlorophenoxy herbicides and contaminants including TCDD. Methods: Eighty-five workers who had been exposed to either high (n = 47) or low (n = 38) TCDD levels more than 30 years before serum collection were included in the current investigation. Plasma level of 16 cytokines, 10 chemokines, and 6 growth factors were measured. Current plasma levels of TCDD (TCDDcurrent) were determined by high-resolution gas chromatography/isotope-dilution high-resolution mass spectrometry. TCDD blood levels at the time of last exposure (TCDDmax) were estimated using a one-compartment first order kinetic model. Results: Blood levels of most analytes had a negative association with current and estimated past maximum TCDD levels. These decreases reached formal statistical significance for fractalkine, transforming growth factor alpha (TGF-α), and fibroblast growth factor 2 (FGF2) with increasing TCDD levels. Conclusion: Our study showed a general reduction in most analyte levels with the strongest effects for fractalkine, FGF2, and TGF-α. These findings suggest that TCDD exposure could suppress the immune system and that chemokine and growth factor-dependent cellular pathway changes by TCDD may play role in TCDD toxicity and associated health effects. PMID:22655272

ASSESSING TCDD WASTING SYNDROME IN AN IN VIVO OBESITY MODEL

EPA Science Inventory

TCDD is a by-product of incineration commonly found as a microcontaminant in the food supply. The TCDD wasting syndrome, characterized by prolonged weight loss, has been examined for decades. Much of this work has focused on high dose in vivo and in vitro studies....

DEVELOPMENTAL TOXICITY OF TCDD AND RELATED COMPOUNDS: SENSITIVITIES AND DIFFERENCES

EPA Science Inventory

The issue of the developmental toxicity of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) and related compounds has been the subject of two recent reviews (Morrissey and Schwetz, 1989; Couture et al., 1990a). here is little doubt that TCDD is one of the most potent developmental tox...

Obesity and perinatal TCDD exposure increases mammary tumors in FVB mice

EPA Science Inventory

Risk of breast cancer has been consistently shown to correlate to total lifetime exposure to estrogens. Because both TCDD exposure and the state of obesity interact with the estrogen pathway, we wanted to investigate how TCDD and obesity interact with mammary cancer susceptibili...

MECHANISMS OF TCDD-INDUCTION OF CLEFT PALATE: INSIGHTS FROM IN VIVO AND IN VITRO APPROACHES

EPA Science Inventory

TCDD induced cleft palate (CP) in C57BL6N embryos by altering proliferation and differentiation of palatal medial epithelial cells. hese effects correlated with altered expression of the growth factors, TGF-a,EGF. TGF-B1 and TGF-B2, and the EGF receptor. ynergistic interactions b...

TCDD and cancer: A critical review of epidemiologic studies

PubMed Central

Boffetta, Paolo; Mundt, Kenneth A; Adami, Hans-Olov; Cole, Philip; Mandel, Jack S

2011-01-01

The authors reviewed the epidemiologic studies on exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and cancer risk, published since the last full-scale review made by the International Agency for Research on Cancer Monographs program in 1997. The update of a cohort of US herbicide producers generated negative results overall; the internal analysis provided evidence of an increased “all-cancer” risk in the highest exposure category, with a statistically significant exposure-response association in some of the many analyses performed.The update of a similar Dutch cohort did not confirm the previously observed association with TCDD exposure. The updated surveillance of the Seveso population provided evidence of increased all-cancer mortality 15-20 years after exposure among those living in the most contaminated area but might also reflect random variation, as overall excesses in the most recent follow-up were not observed. Corresponding data on cancer incidence offer little support to the mortality results. Updated results from cohort studies of Vietnam veterans potentially exposed to TCDD did not consistently suggest an increased risk of cancer. Results of additional, smaller studies of other occupational groups potentially exposed to TCDD, and of community-based case-control studies, did not provide consistent evidence of an increased cancer risk. In conclusion, recent epidemiological evidence falls far short of conclusively demonstrating a causal link between TCDD exposure and cancer risk in humans. The emphasis on results for overall cancer risk—rather than risk for specific neoplasms—is notjustified on epidemiologic grounds and is nota reason for ignoring the weaknesses of the available evidence. PMID:21718216

Induction of a chloracne phenotype in an epidermal equivalent model by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is dependent on aryl hydrocarbon receptor activation and is not reproduced by aryl hydrocarbon receptor knock down.

PubMed

Forrester, Alison R; Elias, Martina S; Woodward, Emma L; Graham, Mark; Williams, Faith M; Reynolds, Nick J

2014-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent activator of the aryl hydrocarbon receptor (AhR) and causes chloracne in humans. The pathogenesis and role of AhR in chloracne remains incompletely understood. To elucidate the mechanisms contributing to the development of the chloracne-like phenotype in a human epidermal equivalent model and identify potential biomarkers. Using primary normal human epidermal keratinocytes (NHEK), we studied AhR activation by XRE-luciferase, AhR degradation and CYP1A1 induction. We treated epidermal equivalents with high affinity TCDD or two non-chloracnegens: β-naphthoflavone (β-NF) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Using Western blotting and immunochemistry for filaggrin (FLG), involucrin (INV) and transglutaminase-1 (TGM-1), we compared the effects of the ligands on keratinocyte differentiation and development of the chloracne-like phenotype by H&E. In NHEKs, activation of an XRE-luciferase and CYP1A1 protein induction correlated with ligand binding affinity: TCDD>β-NF>ITE. AhR degradation was induced by all ligands. In epidermal equivalents, TCDD induced a chloracne-like phenotype, whereas β-NF or ITE did not. All three ligands induced involucrin and TGM-1 protein expression in epidermal equivalents whereas FLG protein expression decreased following treatment with TCDD and β-NF. Inhibition of AhR by α-NF blocked TCDD-induced AhR activation in NHEKs and blocked phenotypic changes in epidermal equivalents; however, AhR knock down did not reproduce the phenotype. Ligand-induced CYP1A1 and AhR degradation did not correlate with their chloracnegenic potential, indicating that neither CYP1A1 nor AhR are suitable biomarkers. Mechanistic studies showed that the TCDD-induced chloracne-like phenotype depends on AhR activation whereas AhR knock down did not appear sufficient to induce the phenotype. Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier

SHP-1 is directly activated by the aryl hydrocarbon receptor and regulates BCL-6 in the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

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

Phadnis-Moghe, Ashwini S.; Li, Jinpeng

2016-11-01

The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which is a strong AHR agonist, causes significant suppression of human B cell activation and differentiation. The current studies describe the identification of Src homology phosphatase 1 (SHP-1) encoded by the gene PTPN6 as a putative regulator of TCDD-mediated suppression of B cell activation. Shp-1 was initially identified through a genome-wide analysis of AHR binding in mouse B cells in the presence of TCDD. The binding of AHR to the PTPN6 promoter was further confirmed using electrophoretic mobility shift assays in which, specific binding of AHR was detected at four putative DRE sites within PTPN6more » promoter. Time-course measurements performed in human B cells highlighted a significant increase in SHP-1 mRNA and protein levels in the presence of TCDD. The changes in the protein levels of SHP-1 were also observed in a TCDD concentration-dependent manner. The increase in SHP-1 levels was also seen to occur due to a change in early signaling events in the presence of TCDD. We have shown that BCL-6 regulates B cell activation by repressing activation marker CD80 in the presence of TCDD. TCDD-treatment led to a significant increase in the double positive (SHP-1{sup hi} BCL-6{sup hi}) population. Interestingly, treatment of naïve human B cells with SHP-1 inhibitor decreased BCL-6 protein levels suggesting possible regulation of BCL-6 by SHP-1 for the first time. Collectively, these results suggest that SHP-1 is regulated by AHR in the presence of TCDD and may, in part through BCL-6, regulate TCDD-mediated suppression of human B cell activation. - Highlights: • SHP-1 encoded by the gene PTPN6 is directly activated by the AHR. • AHR binds to dioxin response elements within the SHP-1 promoter in a TCDD-inducible manner. • TCDD-mediated increase in SHP-1 levels is observed in primary human B cells. • Higher SHP-1 levels help in maintaining high BCL-6 levels in the presence of TCDD

ANALYSIS OF 2,3,7,8-TCDD TUMOR PROMOTION ACTIVITY AND ITS RELATIONSHIP TO CANCER

EPA Science Inventory

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has a high estimated cancer potency in animals which has been reasoned to imply that TCDD might be carcinogenic to man. The animal cancer data show that TCDD can act in a solitary manner causing tumors without the participation of other ...

Obesity and perinatal TCDD exposure increases mammary tumor incidence in FVB mice

EPA Science Inventory

Breast cancer risk consistently correlates with total lifetime exposure to estrogens. Because both TCDD and adipocytes impact the estrogen pathway, we examined how TCDD and obesity interact to alter mammary cancer susceptibility. At 12.5 days post conception, we exposed FVB fema...

EVIDENCE FOR EGFR PATHWAY MEDIATION OF CLEFT PALATE INDUCTION BY TCDD

EPA Science Inventory

EVIDENCE FOR EGFR PATHWAY MEDIATION OF CLEFT PALATE INDUCTION BY TCDD. B D Abbott, A R Buckalew, and K E Leffler. RTD, NHEERL, ORD,US EPA, RTP, NC, USA.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is teratogenic in C57BL/6J mice, producing cleft palate (CP) after exposure...

LASER CAPTURE MICRODISSECTION AND GENE ARRAY ANALYSIS OF PALATAL EPITHELIAL AND MESENCHYMAL CELLS EXPOSED TO TCDD

EPA Science Inventory

Palatal shelves from embryos exposed on gestation day (GD) 12 to either retinoic acid (RA) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) contact but fail to fuse. It is of interest to know if diverse agents that induce clefting via the same etiology also activate the same biochem...

THE INFLUENCE OF VARIABLE ELIMINATION RATE AND BODY FAT MASS IN A PBPK MODEL FOR TCDD IN PREDICTING THE SERUM TCDD CONCENTRATIONS FROM VETERANS OF OPERATION RANCH HAND

EPA Science Inventory

The Influence of Variable Elimination Rate and Body Fat Mass in a PBPK Model for TCDD in Predicting the Serum TCDD Concentrations from Veterans of Operation Ranch Hand.
C Emond1,2, LS Birnbaum2, JE Michalek3, MJ DeVito2
1 National Research Council, National Academy of Scien...

Agent Orange Exposure and 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) in Human Milk.

PubMed

Scialli, Anthony R; Watkins, Deborah K; Ginevan, Michael E

2015-06-01

Agent Orange was sprayed in parts of southern Vietnam during the U.S.-Vietnam war and was a mixture of two chlorophenoxy herbicides. The mixture was contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD and other dioxins and furans are measurable in the milk of Vietnamese women. We explored whether the TCDD in milk from these women was from Agent Orange and whether lactational exposure can be a mode of transgenerational effects of TCDD from Agent Orange. A review of the world's literature on milk concentrations of polychlorinated compounds showed the presence of TCDD and other dioxins and furans in all countries that have been assessed. The congener profile of these chemicals, that is, the proportion of different congeners in the sample, can be used to assess the source of milk contamination. Measurements in most countries, including contemporary measurements in Vietnam, are consistent with non-Agent Orange exposure sources, including industrial activities and incineration of waste. Models and supporting human data suggest that TCDD from breastfeeding does not persist in a child past adolescence and that the adult body burden of TCDD is independent of whether the individual was breast- or bottle-fed as a child. These findings suggest that exposure to Agent Orange in Vietnam did not result in persistent transgenerational exposure through human milk. © 2015 Wiley Periodicals, Inc.

Morbidity in New Zealand pesticide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

PubMed

't Mannetje, Andrea; Eng, Amanda; Walls, Chris; Dryson, Evan; Douwes, Jeroen; Bertazzi, Pier; Ryder-Lewis, Simon; Scott, David; Brooks, Collin; McLean, Dave; Cheng, Soo; Pearce, Neil

2018-01-01

To conduct a cross-sectional morbidity survey among 245 former employees of a pesticide production plant exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in New Zealand. Demographic factors and health information were collected in face-to-face interviews. TCDD, lipids, thyroid hormones, glucose and immunoglobulin G (IgG) were determined in non-fasting blood. For 111 participants, a neurological examination was conducted. Associations between health outcomes and working in a TCDD exposed job (prevalence 49%) and serum TCDD concentration≥10pg/g lipid (18%) were assessed using logistic regression whilst controlling for age, gender, smoking, body mass index and ethnicity. Diabetes was more common in those who had worked in TCDD exposed jobs (OR 4.0, 95%CI 1.0-15.4) and in those with serum TCDD ≥10pg/g (OR 3.1, 95%CI 0.9-10.7). Non-fasting glucose levels >6.6mmol/l were more common in those with TCDD exposed jobs (OR 3.6, 95%CI 1.0-12.9), as were serum free thyroxine 4<12.8pmol/l (OR 4.5, 95%CI 1.4-14.4), triglycerides >1.7mmol/l (OR 2.5, 95%CI 1.1-5.7) and high density lipoprotein cholesterol (HDL) <1mmol/l (OR 4.0, 95%CI 1.2-13.2). IgG was negatively associated with TCDD (linear regression p=0.05). The neurological examination revealed a higher frequency of abnormal reflexes in those with serum TCDD ≥10pg/g (OR 4.8, 95%CI 1.1-21.0). In this occupationally exposed population, TCDD was associated with an increased risk of diabetes and a range of subclinical responses in multiple systems (peripheral nervous system, immune system, thyroid hormones and lipid metabolism), several decades after last exposure. These results need to be interpreted with caution due to the small study size and the cross-sectional nature of the study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Induction of a chloracne phenotype in an epidermal equivalent model by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is dependent on aryl hydrocarbon receptor activation and is not reproduced by aryl hydrocarbon receptor knock down

PubMed Central

Forrester, Alison R.; Elias, Martina S.; Woodward, Emma L.; Graham, Mark; Williams, Faith M.; Reynolds, Nick J.

2014-01-01

Background 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent activator of the aryl hydrocarbon receptor (AhR) and causes chloracne in humans. The pathogenesis and role of AhR in chloracne remains incompletely understood. Objective To elucidate the mechanisms contributing to the development of the chloracne-like phenotype in a human epidermal equivalent model and identify potential biomarkers. Methods Using primary normal human epidermal keratinocytes (NHEK), we studied AhR activation by XRE-luciferase, AhR degradation and CYP1A1 induction. We treated epidermal equivalents with high affinity TCDD or two non-chloracnegens: β-naphthoflavone (β-NF) and 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Using Western blotting and immunochemistry for filaggrin (FLG), involucrin (INV) and transglutaminase-1 (TGM-1), we compared the effects of the ligands on keratinocyte differentiation and development of the chloracne-like phenotype by H&E. Results In NHEKs, activation of an XRE-luciferase and CYP1A1 protein induction correlated with ligand binding affinity: TCDD > β-NF > ITE. AhR degradation was induced by all ligands. In epidermal equivalents, TCDD induced a chloracne-like phenotype, whereas β-NF or ITE did not. All three ligands induced involucrin and TGM-1 protein expression in epidermal equivalents whereas FLG protein expression decreased following treatment with TCDD and β-NF. Inhibition of AhR by α-NF blocked TCDD-induced AhR activation in NHEKs and blocked phenotypic changes in epidermal equivalents; however, AhR knock down did not reproduce the phenotype. Conclusion Ligand-induced CYP1A1 and AhR degradation did not correlate with their chloracnegenic potential, indicating that neither CYP1A1 nor AhR are suitable biomarkers. Mechanistic studies showed that the TCDD-induced chloracne-like phenotype depends on AhR activation whereas AhR knock down did not appear sufficient to induce the phenotype. PMID:24161567

Proteomic analysis of human bladder epithelial cells by 2D blue native SDS-PAGE reveals TCDD-induced alterations of calcium and iron homeostasis possibly mediated by nitric oxide.

PubMed

Verma, Nisha; Pink, Mario; Petrat, Frank; Rettenmeier, Albert W; Schmitz-Spanke, Simone

2015-01-02

A proteomic analysis of the interaction among multiprotein complexes involved in 2,3,7,8-dibenzo-p-dioxin (TCDD)-mediated toxicity in urinary bladder epithelial RT4 cells was performed using two-dimensional blue native SDS-PAGE (2D BN/SDS-PAGE). To enrich the protein complexes, unexposed and TCDD-exposed cells were fractionated. BN/SDS-PAGE of the resulting fractions led to an effective separation of proteins and protein complexes of various origins, including cell membrane, mitochondria, and other intracellular compartments. Major differences between the proteome of control and exposed cells involved the alteration of many calcium-regulated proteins (calmodulin, protein S100-A2, annexin A5, annexin A10, gelsolin isoform b) and iron-regulated proteins (ferritin, heme-binding protein 2, transferrin). On the basis of these findings, the intracellular calcium concentration was determined, revealing a significant increase after 24 h of exposure to TCDD. Moreover, the concentration of the labile iron pool (LIP) was also significantly elevated in TCDD-exposed cells. This increase was strongly inhibited by the calmodulin (CaM) antagonist W-7, which pointed toward a possible interaction between iron and calcium signaling. Because nitric oxide (NO) production was significantly enhanced in TCDD-exposed cells and was also inhibited by W-7, we hypothesize that alterations in calcium and iron homeostasis upon exposure to TCDD may be linked through NO generated by CaM-activated nitric oxide synthase. In our model, we propose that NO produced upon TCDD exposure interacts with the iron centers of iron-regulatory proteins (IRPs) that modulate the alteration of ferritin and transferrin, resulting in an augmented cellular LIP and, hence, increased toxicity.

Correlation of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced apoptotic cell death in the embryonic vasculature with embryotoxicity

USGS Publications Warehouse

Cantrell, Susannah M.; Joy-Schlezinger, Jennifer; Stegeman, John J.; Tillitt, Donald E.; Hannington, Mark D.

1998-01-01

Vertebrate embryos are particularly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Identification of tissues that are susceptible to the adverse effects of TCDD is requisite for understanding the embryo toxic effects of TCDD. The objective of the present study was to quantitate the temporal appearance of and dose dependence of apoptosis in TCDD-exposed medaka embryos (Oryzias latipes). A fluorescent-based DNA end-labeling assay provided a sensitive method for detection of TCDD-induced apoptosis in tissue sections of medaka embryos. Apoptotic cells were readily apparent in the medial yolk vein at all observed embryonic stages in TCDD-exposed embryos. Slope-comparison analysis indicated that TCDD-induced programmed cell death in the embryonic medial yolk vein was mechanistically linked to embryo mortality. These data are consistent with the hypothesis that vascular damage contributes to the acute embryo toxic effects of TCDD. However, as sublethal concentrations of dioxin-like compounds are more typical of environmental exposures, tissue damage was also assessed in medaka fry that were exposed to low doses of TCDD during embryonic development. Cell death was detected in gill and digestive tissues in visibly healthy medaka fry that had been exposed to low doses of TCDD during embryonic development. Increased expression of cytochrome P450 1A is a major biochemical consequence of TCDD exposure and is often used as a biomarker for exposure to dioxin-like compounds. Therefore, we compared the tissue distribution of TCDD-induced P450 1A expression and TCDD-induced programmed cell death. TCDD-induced programmed cell death co-localized with TCDD-induced P450 1A expression in both embryos and in visibly healthy post-hatch fry. Our results suggest that aberrant programmed cell death may be a suitable marker for exposure of feral organisms to dioxin-like compounds.

DISPOSITION OF TCDD IN A MOUSE MODEL OF OBESITY AND TYPE II DIABETESE

EPA Science Inventory

Recent epidemiology studies have shown an association between type II diabetes and exposure to TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin). A possible explanation is that diabetics have a slower elimination of TCDD than non-diabetics. The objective of the present study was to ex...

Increases in levels of epoxyeicosatrienoic and dihydroxyeicosatrienoic acids (EETs and DHETs) in liver and heart in vivo by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and in hepatic EET:DHET ratios by cotreatment with TCDD and the soluble epoxide hydrolase inhibitor AUDA.

PubMed

Diani-Moore, Silvia; Ma, Yuliang; Gross, Steven S; Rifkind, Arleen B

2014-02-01

The environmental toxin and carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) binds and activates the transcription factor aryl hydrocarbon receptor (AHR), inducing CYP1 family cytochrome P450 enzymes. CYP1A2 and its avian ortholog CYP1A5 are highly active arachidonic acid epoxygenases. Epoxygenases metabolize arachidonic acid to four regioisomeric epoxyeicosatrienoic acids (EETs) and selected monohydroxyeicosatetraenoic acids (HETEs). EETs can be further metabolized by epoxide hydrolases to dihydroxyeicosatrienoic acids (DHETs). As P450-arachidonic acid metabolites affect vasoregulation, responses to ischemia, inflammation, and metabolic disorders, identification of their production in vivo is needed to understand their contribution to biologic effects of TCDD and other AHR activators. Here we report use of an acetonitrile-based extraction procedure that markedly increased the yield of arachidonic acid products by lipidomic analysis over a standard solid-phase extraction protocol. We show that TCDD increased all four EETs (5,6-, 8,9-, 11,12-, and 14,15-), their corresponding DHETs, and 18- and 20-HETE in liver in vivo and increased 5,6-EET, the four DHETs, and 18-HETE in heart, in a chick embryo model. As the chick embryo heart lacks arachidonic acid-metabolizing activity, the latter findings suggest that arachidonic acid metabolites may travel from their site of production to a distal organ, i.e., heart. To determine if the TCDD-arachidonic acid-metabolite profile could be altered pharmacologically, chick embryos were treated with TCDD and the soluble epoxide hydrolase inhibitor 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA). Cotreatment with AUDA increased hepatic EET-to-DHET ratios, indicating that the in vivo profile of P450-arachidonic acid metabolites can be modified for potential therapeutic intervention.

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) persistence in the Seveso (Milan, Italy) soil.

PubMed

Cerlesi, S; Di Domenico, A; Ratti, S

1989-10-01

Preliminary results of a new study on TCDD environmental persistence at Seveso (Milan, Italy) are presented. For this study, the most contaminated territory, Zone A, was divided into areas to fractionate the available TCDD levels in soil into data sets with reduced value spreads. In addition, various time subsets were defined for each area. Selected data were fitted with the exponential model y = y0.e-k.1. It was estimated that at least 1.2 kg TCDD was present in Zone A shortly after the accident. On average, a considerable portion (23%) of this amount lay on vegetation; TCDD which was not photodegraded or volatilized before the heavy rains of fall 1976, was later washed off and transferred to ground by water action. From this study, mean analytical underestimations affecting January 1977 and March 1978 contamination map data were on the order of 30 and 24%. All the above figures are considered optimistic. A few years after the accident, mean TCDD half-life in soil appeared to be 9.1y (t1/2-95% CLs, 6.2-17y).

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on development of anuran amphibians

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

Jung, R.E.; Walker, M.K.

1997-02-01

The authors exposed anuran eggs and tadpoles to vehicle control (0.7% acetone) or waterborne [{sup 3}H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 24 h and subsequently raised them in clean water. Neither American toads nor green frogs exhibited TCDD-related mortality, but leopard frogs showed significantly increased mortality over controls. Eggs and tadpoles eliminated TCDD relatively quickly compared with published data for other vertebrates, with t{sub {1/2}} of 1 to 5 d (American toad), 2 to 7 d (leopard frog), and 4 to 6 d (green frog). Elimination rates were slowest for tadpoles fed nothing, fastest for those fed a low-fat diet, and intermediate formore » those fed a high-fat diet. Although not significant, American toads exposed to {ge}0.03 {micro}g TCDD/L appeared to metamorphose earlier, and those exposed to higher TCDD treatments appeared to metamorphose at a larger body mass than controls. Comparisons of these results with studies of fish early life stages suggest that anuran eggs and tadpoles eliminate TCDD more rapidly and are 100- to 1,000-fold less sensitive to its deleterious effects during development. These differences may be related to differences in metabolic rate, patterns of lipid storage and utilization, and aryl hydrocarbon receptor binding and signal transduction.« less

SEVESO WOMEN'S HEALTH STUDY: DOES ZONE OF RESIDENCE PREDICT INDIVIDUAL TCDD EXPOSURE? (R824761)

EPA Science Inventory

The compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is produced as an unwanted by-product of various chemical reactions and combustion processes, including the manufacture of chlorinated phenols and derivatives. In animals, TCDD exposure is associated with toxic, car...

Adsorption of TCDD molecule onto CNTs and BNNTs: Ab initio van der Waals density-functional study

NASA Astrophysics Data System (ADS)

Darvish Ganji, M.; Alinezhad, H.; Soleymani, E.; Tajbakhsh, M.

2015-03-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCCD) is one of the most dangerous compounds that infect the environment and hence its removal is crucial for safety in human life. In this work, we have investigated the interaction of TCDD with boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) by using the density functional theory (DFT) calculations. Our first-principles results have been validated by experiment and also other theoretical values for the similar system. The adsorption energies for TCDD molecule on the BNNTs and CNT are calculated. It was found that TCDD adsorption ability of BNNT is slightly stronger than that of CNT and TCDD molecule prefers to be adsorbed on BNNTs with molecular axis parallel to the tube axis. The results obtained indicate that TCDD is weakly bound to the outer surface of all the considered nanotubes and the obtained adsorption energy values and binding distance are typical for the physisorption. We also evaluated the influence of curvature and introduced defects on the TCDD adsorption ability of BNNTs. Furthermore, we have analyzed the electronic structure and charge population for the energetically most favorable complexes and the results indicate that no significant hybridization between the respective orbitals of the two entities was accomplished.

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) persistence in the Seveso (Milan, Italy) soil

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

Cerlesi, S.; Di Domenico, A.; Ratti, S.

1989-10-01

Preliminary results of a new study on TCDD environmental persistence at Seveso (Milan, Italy) are presented. For this study, the most contaminated territory, Zone A, was divided into areas to fractionate the available TCDD levels in soil into data sets with reduced value spreads. In addition, various time subsets were defined for each area. Selected data were fitted with the exponential model y = y0.e-k.1. It was estimated that at least 1.2 kg TCDD was present in Zone A shortly after the accident. On average, a considerable portion (23%) of this amount lay on vegetation; TCDD which was not photodegradedmore » or volatilized before the heavy rains of fall 1976, was later washed off and transferred to ground by water action. From this study, mean analytical underestimations affecting January 1977 and March 1978 contamination map data were on the order of 30 and 24%. All the above figures are considered optimistic. A few years after the accident, mean TCDD half-life in soil appeared to be 9.1y (t1/2-95% CLs, 6.2-17y).« less

Tissue disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in maternal and developing long-evans rats following subchronic exposure.

PubMed

Hurst, C H; DeVito, M J; Birnbaum, L S

2000-10-01

Prenatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces alterations in the reproductive system of the developing pups. The objective of this study was to determine the disposition of TCDD in maternal and fetal Long-Evans (LE) rats following subchronic exposure, since the adverse reproductive and developmental effects have been extensively characterized in this strain of rat. LE rats were dosed by gavage with 1, 10, or 30 ng [(3)H]TCDD/kg in corn oil, 5 days/week for 13 weeks. At the end of 13 weeks, females were mated and dosing continued every day throughout gestation. Dams were sacrificed on gestation day (GD) 9, GD16, GD21, and post-natal day 4 and analyzed for [(3)H]TCDD-derived activity in maternal and fetal tissues. Maternal body burdens were equivalent at different time points, indicating that the dams were at steady state. Maternal body burdens were approximately 19, 120, and 300 ng TCDD/kg following doses of 1, 10, and 30 ng TCDD/kg, respectively. Individual embryo concentrations on GD9 were 1.6, 7, and 16 pg TCDD/g after maternal exposure of 1, 10, and 30 ng/kg/d, respectively. On GD 16, fetal liver, urogenital tract, head, and body concentrations were similar and averaged 1.4, 7.8, and 16.4 pg TCDD/g after administration of 1, 10, or 30 ng TCDD/kg/d, respectively, indicating no preferential sequestration within the different fetal tissues. These concentrations of TCDD within fetal tissues after subchronic exposure are comparable to those seen after a single dose of 50, 200, or 1000 ng TCDD/kg administered on GD15, a critical period of gestation.

TCDD causes stimulation of c-ras expression in the hepatic plasma membranes in vivo and in vitro.

PubMed

Tullis, K; Olsen, H; Bombick, D W; Matsumura, F; Jankun, J

1992-01-01

A series of in vivo and in vitro experiments were conducted to determine the effects of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) administered on the expression of c-ras. Differences in c-ras expression between control and TCDD treated groups were determined by immunoassay of p21ras protein, or indirectly measured by the specific binding of 3H-GTP to hepatic plasma membrane preparations. Intraperitoneal injection of sublethal doses of TCDD significantly elevated (P less than 0.05, Student t test) levels of hepatic p21ras protein in Sprague-Dawley rats and TCDD sensitive C57BL/6J mice. Such an increase occurred at an early stage of poisoning in the C57BL/6J mice. The earliest increase was detectable 6 hr after dosing, and the difference became statistically significant by 12 and 24 hr after dosing. In contrast, TCDD tolerant DBA/2J mice had only a marginal increase in hepatic p21ras protein which did not become statistically significant even at 24 hr host-dosing. TCDD evoked increases in hepatic p21ras protein of C57BL/6J mice were accompanied by the increase in the specific binding of GTP to hepatic plasma membranes. Column chromatography of solubilized rat hepatic membrane proteins on sephadex G-50 showed TCDD administration increased levels of a 3H-GTP binding protein with MW of approximately 21 Kd. 3H-GTP binding in total hepatic membranes was also elevated (P less than 0.05, Fisher PLSD multiple comparison test) 6 hr and 24 hr after dosing of C57BL/6J mice, but as expected the effect of TCDD was not as conspicuous as that found in the plasma membrane. TCDD treatment increased levels of a 21 Kd protein found in the in vitro translation products of RNA purified from guinea pig liver. This protein was identified as a c-ras protein based upon its ability to bind GTP, precipitation by a polyclonal antibody against the rasHa and Ki proteins and subsequent SDS-PAGE which showed a single protein band of approximately 21 Kd.

LACK OF EXPRESSION OF EGF AND TGF-ALPHA IN THE FETAL MOUSE ALTERS FORMATION OF PROSTATIC EPITHELIAL BUDS AND INFLUENCES THE RESPONSE TO TCDD

EPA Science Inventory

Lack of Expression of EGF and TGF in the Fetal Mouse Alters Formation of Prostatic Epithelial Buds and Responsiveness to TCDD-Induced Impairment of Prostatic Bud Formation.

Barbara D. Abbott, Tien-Min Lin, Nathan T. Rasmussen, Robert W. Moore,
Ralph M. Albrecht, Judi...

COMPARATIVE SENSITIVITY OF DIFFERENT LIFE-STAGES OF MEDAKA AND SALMONID FISHES TO 2,3,7,8-TCDD

EPA Science Inventory

The early life stages of fish are known to be more sensitive than the adults to the toxicological effects of 2,3,7,8-tetrachlorodibenzo(p)dioxin (TCDD). Embryo larval stages of medake, for example, experience 50% lethality when TCDD residues in the eggs are 1396 pg/g. By contrast...

Progesterone-dependent Regulation of Endometrial Cannabinoid Receptor Type 1 (CB1-R) Expression is Disrupted in Women with Endometriosis and in Isolated Stromal Cells Exposed to TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)

PubMed Central

Resuehr, David; Glore, Dana R.; Taylor, Hugh S.; Bruner-Tran, Kaylon L.; Osteen, Kevin G.

2012-01-01

Objective To examine the differentiation-related expression of CB1-R mRNA and protein in endometrial tissue obtained from women with and without endometriosis and to determine the impact of acute TCDD exposure on CB1-R gene expression in isolated endometrial stromal cells. Design Laboratory-based study Setting University-affiliated medical center Patients Women with and without endometriosis undergoing volunteer endometrial biopsies after informed consent. Interventions None Main Outcome Measures Analysis of in vivo CB1-R mRNA and protein expression in human endometrial tissues and mRNA expression in isolated stromal cells following exposure to TCDD or a progesterone receptor antagonist (Onapristone). Results CB1-R mRNA and protein expression was highest during the progesterone-dominated secretory phase in control women, while expression was minimal in endometrial tissues acquired from women with endometriosis, regardless of the cycle phase. Although progesterone was found to induce CB1-R mRNA expression in endometrial stromal cells from control donors, steroid-induced expression of this gene was inhibited by co-treatment with either TCDD or Onapristone. Conclusions Our studies reveal a role for the anti-inflammatory actions of progesterone in regulating endometrial cannabinoid signaling, which is disrupted in women with endometriosis. Significantly, our studies demonstrate, for the first time, that acute TCDD exposure disrupts cannabinoid signaling in the human endometrium. PMID:22789143

Receptor-dependent mechanisms of glucocorticoid and dioxin-induced cleft palate

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

Pratt, R.M.

1985-09-01

Glucocorticoids (triamcinolone) and dioxins (TCDD) are highly specific teratogens in the mouse, in that cleft palate is the major malformation observed. Glucocorticoids and TCDD both readily cross the yolk sac and placenta and appear in the developing secondary palate. Structure-activity relationships for glucocorticoid- and TCDD-induced cleft palate suggest a receptor involvement. Receptors for glucocorticoids and TCDD are present in the palate and their levels in various mouse strains are highly correlated with their sensitivity to cleft palate induction. Receptors for glucocorticoids appear to be more prevalent in the palatal mesenchymal cells whereas those for TCDD are probably located in themore » palatal epithelial cells. Glucocorticoids exert their teratogenic effect on the palate by inhibiting the growth of the palatal mesenchymal cells whereas TCDD alters the terminal cell differentiation of the media palatal epithelial cells. 71 references.« less

EFFECTS OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) ON FETAL MOUSE URINARY TRACT EPITHELIUM IN VITRO

EPA Science Inventory

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), produces hydronephrosis by altering the differentiation and proliferation of ureteric epithelial cells in the embryonic C57BL/6N mouse urinary tract. This study examines the effects of TCDD on late gestation fetal urinary tract cells u...

Toxicogenomic investigation of Tetrahymena thermophila exposed to dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

PubMed

Chang, Yue; Feng, LiFang; Miao, Wei

2011-07-01

Dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are persistent in the environment and cause continuous toxic effects in humans and aquatic life. Tetrahymena thermophila has the potential for use as a model for research regarding toxicants. In this study, this organism was used to analyze a genome-wide microarray generated from cells exposed to DDT, TBT and TCDD. To accomplish this, genes differentially expressed when treated with each toxicant were identified, after which their functions were categorized using GO enrichment analysis. The results suggested that the responses of T. thermophila were similar to those of multicellular organisms. Additionally, the context likelihood of relatedness method (CLR) was applied to construct a TCDD-relevant network. The T-shaped network obtained could be functionally divided into two subnetworks. The general functions of both subnetworks were related to the epigenetic mechanism of TCDD. Based on analysis of the networks, a model of the TCDD effect on T. thermophila was inferred. Thus, Tetrahymena has the potential to be a good unicellular eukaryotic model for toxic mechanism research at the genome level.

TCDD decreases ATP levels and increases reactive oxygen production through changes in mitochondrial F F{sub 1}-ATP synthase and ubiquinone

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

Shertzer, Howard G.; Genter, Mary Beth; Shen, Dongxiao

2006-12-15

Mitochondria generate ATP and participate in signal transduction and cellular pathology and/or cell death. TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) decreases hepatic ATP levels and generates mitochondrial oxidative DNA damage, which is exacerbated by increasing mitochondrial glutathione redox state and by inner membrane hyperpolarization. This study identifies mitochondrial targets of TCDD that initiate and sustain reactive oxygen production and decreased ATP levels. One week after treating mice with TCDD, liver ubiquinone (Q) levels were significantly decreased, while rates of succinoxidase and Q-cytochrome c oxidoreductase activities were increased. However, the expected increase in Q reduction state following TCDD treatment did not occur; instead, Q wasmore » more oxidized. These results could be explained by an ATP synthase defect, a premise supported by the unusual finding that TCDD lowers ATP/O ratios without concomitant changes in respiratory control ratios. Such results suggest either a futile cycle in ATP synthesis, or hydrolysis of newly synthesized ATP prior to release. The TCDD-mediated decrease in Q, concomitant with an increase in respiration, increases complex 3 redox cycling. This acts in concert with glutathione to increase membrane potential and reactive oxygen production. The proposed defect in ATP synthase explains both the greater respiratory rates and the lower tissue ATP levels.« less

The tertiary structures of porcine AhR and ARNT proteins and molecular interactions within the TCDD/AhR/ARNT complex.

PubMed

Orlowska, Karina; Molcan, Tomasz; Swigonska, Sylwia; Sadowska, Agnieszka; Jablonska, Monika; Nynca, Anna; Jastrzebski, Jan P; Ciereszko, Renata E

2016-06-01

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activated by structurally diverse synthetic and natural chemicals, including toxic environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In the present study, homology models of the porcine AhR-ligand binding domain (LBD) and the porcine aryl hydrocarbon receptor nuclear translocator-ligand binding domain (ARNT-LBD) were created on the basis of structures of closely related respective proteins i.e., human Hif-2α and ARNT. Molecular docking of TCDD to the porcine AhR-LBD model revealed high binding affinity (-8.8kcal/mol) between TCDD and the receptor. Moreover, formation of the TCDD/AhR-LBD complex was confirmed experimentally with the use of electrophoretic mobility shift assay (EMSA). It was found that TCDD (10nM, 2h of incubation) not only bound to the AhR in the porcine granulosa cells but also activated the receptor. The current study provides a framework for examining the key events involved in the ligand-dependent activation of the AhR. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of vitamin B12 on cleft palate induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and dexamethasone in mice*

PubMed Central

Zhao, Shu-fan; Chai, Mao-zhou; Wu, Min; He, Yong-hong; Meng, Tian; Shi, Bing

2014-01-01

The purpose of this study was to investigate the effect of vitamin B12 on palatal development by co-administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dexamethasone (DEX). We examined the morphological and histological features of the palatal shelf and expression levels of key signaling molecules (transforming growth factor-β3 (TGF-β3) and TGF-β type I receptor (activin receptor-like kinase 5, ALK5)) during palatogenesis among a control group (Group A), TCDD+DEX exposed group (Group B), and TCDD+DEX+vitamin B12 exposed group (Group C). While we failed to find that vitamin B12 decreased the incidence of cleft palate induced by TCDD+DEX treatment, the expression levels of key signaling molecules (TGF-β3 and ALK5) during palatogenesis were significantly modulated. In TCDD+DEX exposed and TCDD+DEX+vitamin B12 exposed groups, palatal shelves could not contact in the midline due to their small sizes. Our results suggest that vitamin B12 may inhibit the expression of some cleft palate inducers such as TGF-β3 and ALK5 in DEX+TCDD exposed mice, which may be beneficial against palatogenesis to some degree, even though we were unable to observe a protective role of vitamin B12 in morphological and histological alterations of palatal shelves induced by DEX and TCDD. PMID:24599693

Effect of vitamin B12 on cleft palate induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and dexamethasone in mice.

PubMed

Zhao, Shu-Fan; Chai, Mao-Zhou; Wu, Min; He, Yong-Hong; Meng, Tian; Shi, Bing

2014-03-01

The purpose of this study was to investigate the effect of vitamin B12 on palatal development by co-administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dexamethasone (DEX). We examined the morphological and histological features of the palatal shelf and expression levels of key signaling molecules (transforming growth factor-β3 (TGF-β3) and TGF-β type I receptor (activin receptor-like kinase 5, ALK5)) during palatogenesis among a control group (Group A), TCDD+DEX exposed group (Group B), and TCDD+DEX+vitamin B12 exposed group (Group C). While we failed to find that vitamin B12 decreased the incidence of cleft palate induced by TCDD+DEX treatment, the expression levels of key signaling molecules (TGF-β3 and ALK5) during palatogenesis were significantly modulated. In TCDD+DEX exposed and TCDD+DEX+vitamin B12 exposed groups, palatal shelves could not contact in the midline due to their small sizes. Our results suggest that vitamin B12 may inhibit the expression of some cleft palate inducers such as TGF-β3 and ALK5 in DEX+TCDD exposed mice, which may be beneficial against palatogenesis to some degree, even though we were unable to observe a protective role of vitamin B12 in morphological and histological alterations of palatal shelves induced by DEX and TCDD.

Exposure reconstruction for the TCDD-exposed NIOSH cohort using a concentration- and age-dependent model of elimination.

PubMed

Aylward, Lesa L; Brunet, Robert C; Starr, Thomas B; Carrier, Gaétan; Delzell, Elizabeth; Cheng, Hong; Beall, Colleen

2005-08-01

Recent studies demonstrating a concentration dependence of elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest that previous estimates of exposure for occupationally exposed cohorts may have underestimated actual exposure, resulting in a potential overestimate of the carcinogenic potency of TCDD in humans based on the mortality data for these cohorts. Using a database on U.S. chemical manufacturing workers potentially exposed to TCDD compiled by the National Institute for Occupational Safety and Health (NIOSH), we evaluated the impact of using a concentration- and age-dependent elimination model (CADM) (Aylward et al., 2005) on estimates of serum lipid area under the curve (AUC) for the NIOSH cohort. These data were used previously by Steenland et al. (2001) in combination with a first-order elimination model with an 8.7-year half-life to estimate cumulative serum lipid concentration (equivalent to AUC) for these workers for use in cancer dose-response assessment. Serum lipid TCDD measurements taken in 1988 for a subset of the cohort were combined with the NIOSH job exposure matrix and work histories to estimate dose rates per unit of exposure score. We evaluated the effect of choices in regression model (regression on untransformed vs. ln-transformed data and inclusion of a nonzero regression intercept) as well as the impact of choices of elimination models and parameters on estimated AUCs for the cohort. Central estimates for dose rate parameters derived from the serum-sampled subcohort were applied with the elimination models to time-specific exposure scores for the entire cohort to generate AUC estimates for all cohort members. Use of the CADM resulted in improved model fits to the serum sampling data compared to the first-order models. Dose rates varied by a factor of 50 among different combinations of elimination model, parameter sets, and regression models. Use of a CADM results in increases of up to five-fold in AUC estimates for the more

Integration of Genome-Wide Computation DRE Search, AhR ChIP-chip and Gene Expression Analyses of TCDD-Elicited Responses in the Mouse Liver

PubMed Central

2011-01-01

Background The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor (TF) that mediates responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Integration of TCDD-induced genome-wide AhR enrichment, differential gene expression and computational dioxin response element (DRE) analyses further elucidate the hepatic AhR regulatory network. Results Global ChIP-chip and gene expression analyses were performed on hepatic tissue from immature ovariectomized mice orally gavaged with 30 μg/kg TCDD. ChIP-chip analysis identified 14,446 and 974 AhR enriched regions (1% false discovery rate) at 2 and 24 hrs, respectively. Enrichment density was greatest in the proximal promoter, and more specifically, within ± 1.5 kb of a transcriptional start site (TSS). AhR enrichment also occurred distal to a TSS (e.g. intergenic DNA and 3' UTR), extending the potential gene expression regulatory roles of the AhR. Although TF binding site analyses identified over-represented DRE sequences within enriched regions, approximately 50% of all AhR enriched regions lacked a DRE core (5'-GCGTG-3'). Microarray analysis identified 1,896 number of TCDD-responsive genes (|fold change| ≥ 1.5, P1(t) > 0.999). Integrating this gene expression data with our ChIP-chip and DRE analyses only identified 625 differentially expressed genes that involved an AhR interaction at a DRE. Functional annotation analysis of differentially regulated genes associated with AhR enrichment identified overrepresented processes related to fatty acid and lipid metabolism and transport, and xenobiotic metabolism, which are consistent with TCDD-elicited steatosis in the mouse liver. Conclusions Details of the AhR regulatory network have been expanded to include AhR-DNA interactions within intragenic and intergenic genomic regions. Moreover, the AhR can interact with DNA independent of a DRE core suggesting there are alternative mechanisms of AhR-mediated gene regulation. PMID:21762485

GFP Transgenic Medaka (Oryzias latipes) under the Inducible cyp1a Promoter Provide a Sensitive and Convenient Biological Indicator for the Presence of TCDD and Other Persistent Organic Chemicals

PubMed Central

Ng, Grace Hwee Boon; Gong, Zhiyuan

2013-01-01

Persistent organic pollutants (POPs) are resistant to environmental degradation and can cause multitude of health problems. Cytochrome P450 1A (Cyp1a) is often up-regulated by POPs through the activation of aryl hydrocarbon receptor (AhR) pathway and is thus usually used as a biomarker for xenobiotics exposure. To develop a convenient in vivo tool to monitor xenobiotic contamination in the water, we have established GFP transgenic medaka using the inducible cyp1a promoter, Tg(cyp1a:gfp). Here we tested Tg(cyp1a:gfp) medaka at three different stages, prehatching embryos, newly hatched fry and adult with 2,3,7,8-tetrachlorodiebnzo-p-dioxin (TCDD), a dioxin. While GFP induction was observed in all three stages, newly hatched fry were the most sensitive with the lowest observed effective concentration of 0.005 nM or 16.1 ng/L. The highly sensitive organs included the kidney, liver and intestine. With high concentrations of TCDD, several other organs such as the olfactory pit, tail fin, gills, lateral line neuromast cells and blood vessels also showed GFP expression. In addition, Tg(cyp1a:gfp) medaka fry also responded to two other AhR agonists, 3-methylcholanthrene and benzo[a]pyrene, for GFP induction, but no significant GFP induction was observed towards several other chemicals tested, indicating the specificity of this transgenic line. The GFP inducibility of Tg(cyp1a:gfp) medaka at both fry and adult stages may be useful for development of high-throughput assays as well as online water monitoring system to detect xenobiotic toxicity. PMID:23700472

Immunological characterization of the aryl hydrocarbon receptor (AHR) knockout rat in the presence and absence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

PubMed

Phadnis-Moghe, Ashwini S; Chen, Weimin; Li, Jinpeng; Crawford, Robert B; Bach, Anthony; D'Ingillo, Shawna; Kovalova, Natalia; Suarez-Martinez, Jose E; Kaplan, Barbara L F; Harrill, Joshua A; Budinsky, Robert; Rowlands, J Craig; Thomas, Russell S; Kaminski, Norbert E

2016-08-10

The aryl hydrocarbon receptor (AHR) has been extensively characterized for the essential role it plays in mediating the toxic responses elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Despite similarities across animal species, species-specific differences exist in the profile of toxicity and sensitivity to TCDD owing, in part, to differences in the AHR. Newer reports have implicated the importance of AHR in the development and regulation of the immune system. Our present studies seek to further explore the essential role of AHR in lymphoid tissue composition, B cell function and the immunological responses after TCDD administration using the recently established AHR KO rats. Comprehensive immune cell phenotyping showed a decrease in the CD8 + T cell, CD11c + populations and an increase in NKT cells in 3-week-old AHR KO rats compared to the WT controls. The lipopolysaccharide-induced IgM response and proliferation was markedly suppressed in the WT but not in the AHR KO B cells in the presence of TCDD. However, the percentage of LPS-activated IgM + B cells was significantly higher in the AHR KO B cells as compared to that of WT suggesting the role of AHR in regulating the IgM response. The use of an AHR antagonist further alluded to the endogenous role of AHR in regulating B cell responses in the rat. Overall, the studies report for the first time, comprehensive immune cell phenotyping of the AHR KO rat and the endogenous role of AHR in the regulation of B cell function in the rat. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

TCDD and omeprazole prime platelets through the aryl hydrocarbon receptor (AhR) non-genomic pathway.

PubMed

Pombo, Mónica; Lamé, Michael W; Walker, Naomi J; Huynh, Danh H; Tablin, Fern

2015-05-19

The role of the aryl hydrocarbon receptor (AhR) in hemostasis has recently gained increased attention. Here, we demonstrate, by qRT-PCR and western blot, that human platelets express both AhR mRNA and AhR protein. AhR protein levels increase in a dose dependent manner when incubated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or omeprazole. Treatment of platelets with puromycin blocks increased AhR protein synthesis in the presence of AhR activators. Additionally, treatment of platelets with either activator results in phosphorylation of p38MAPK and cPLA2, two key signaling molecules in platelet activation pathways. Using the AhR competitive inhibitors alpha naphthoflavone and CH-223191, we show that phosphorylation of p38MAPK is AhR dependent. Further, inhibition of p38MAPK blocks downstream cPLA2 phosphorylation induced by TCDD or omeprazole. Treatment with AhR activators results in platelet priming, as demonstrated by increased platelet aggregation, which is inhibited by AhR antagonists. Our data support a model of the platelet AhR non-genomic pathway in which treatment with AhR activators results in increased expression of the AhR, phosphorylation of p38MAPK and cPLA2, leading to platelet priming in response to agonist. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-mediated deregulation of myeloid and sebaceous gland stem/progenitor cell homeostasis.

PubMed

Bock, Karl Walter

2017-06-01

Studies of TCDD toxicity stimulated identification of the responsible aryl hydrocarbon receptor (AHR), a multifunctional, ligand-activated transcription factor of the basic helix-loop-helix/Per-Arnt-Sim family. Accumulating evidence suggests a role of this receptor in homeostasis of stem/progenitor cells, in addition to its known role in xenobiotic metabolism. (1) Regulation of myelopoiesis is complex. As one example, AHR-mediated downregulation of human CD34+ progenitor differentiation to monocytes/macrophages is discussed. (2) Accumulation of TCDD in sebum leads to deregulation of sebocyte differentiation via Blimp1-mediated inhibition of c-Myc signaling and stimulation of Wnt-mediated proliferation of interfollicular epidermis. The resulting sebaceous gland atrophy and formation of dermal cysts may explain the pathogenesis of chloracne, the hallmark of TCDD toxicity. (3) TCDD treatment of confluent liver stem cell-like rat WB-F344 cells leads to release from cell-cell contact inhibition via AHR-mediated crosstalk with multiple signaling pathways. Further work is needed to delineate AHR function in crosstalk with other signaling pathways.

INTERACTION OF ESTRADIOL AND 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) IN AN OVULATION MODEL: EVIDENCE FOR SYSTEMIC POTENTIATION AND LOCAL OVARIAN EFFECTS. (R826132)

EPA Science Inventory

Immature rats were treated with estradiol cypionate, (ECP, 0, 0.1, 1, or 2 mg/kg s.c.) followed 24 h later by TCDD (0 or 10 g/kg orally). Follicular development was induced with eC...

Sulforaphane inhibits CYP1A1 activity and promotes genotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in vitro

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

Yang, Fangxing, E-mail: fxyang@zju.edu.cn; Zhuang, Shulin; Zhang, Chao

2013-06-15

Increasing environmental pollution by carcinogens such as some of persistent organic pollutants (POPs) has prompted growing interest in searching for chemopreventive compounds which are readily obtainable. Sulforaphane (SFN) is isolated from cruciferous vegetables and has the potentials to reduce carcinogenesis through various pathways. In this study, we studied the effects of SFN on CYP1A1 activity and genotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The results showed that SFN inhibited TCDD-induced CYP1A1 activity in H4IIE cells by directly inhibiting CYP1A1 activity, probably through binding to aryl hydrocarbon receptor and/or CYP1A1 revealed by molecular docking. However, SFN promoted TCDD-induced DNA damage in yeast cellsmore » and reduced the viability of initiated yeast cells. Besides, it is surprising that SFN also failed to reduce genotoxicity induced by other genotoxic reagents which possess different mechanisms to lead to DNA damage. Currently, it is difficult to predict whether SFN has the potentials to reduce the risk of TCDD based on the conflicting observations in the study. Therefore, further studies should be urgent to reveal the function and mechanism of SFN in the stress of such POPs on human health. - Highlights: • Sulforaphane inhibited TCDD-induced CYP1A1 activity in H4IIE cells. • Sulforaphane may bind to aryl hydrocarbon receptor and/or CYP1A1. • Sulforaphane promoted TCDD-induced DNA damage in yeast cells. • Sulforaphane may promote DNA damage by DNA strand breaks or DNA alkylation.« less

TCDD-MEDIATED OXIDATIVE STRESS IN MALE RAT PUPS FOLLOWING PERINATAL EXPOSURE

EPA Science Inventory

TCDD is a highly persistent trace environmental contaminant and is one of the most potent toxicants known to man. Our laboratory has previously reported an increase in the production of reactive oxygen species (ROS) in the brain of female B6C3F1 mice following subchronic exposur...

COMPARATIVE SENSITIVITY OF DIFFERENT LIFE-STAGES OF MEDAKA (ORYZIAS LATIPES) AND BROOK TROUT (SALVELINUS FONTINALIS) TO 2,3,7,8-TCDD

EPA Science Inventory

The early life stages of fish are known to be more sensitive than the adults to the toxicological effects of 2,3,7,8-tetrachlorodibenzo(p)dioxide (TCDD). TCDD concentrations in surface waters are sufficiently low that direct exposure of the developing embryo is unlikely to be o...

Phase matrix induced symmetrics for multiple scattering using the matrix operator method

NASA Technical Reports Server (NTRS)

Hitzfelder, S. J.; Kattawar, G. W.

1973-01-01

Entirely rigorous proofs of the symmetries induced by the phase matrix into the reflection and transmission operators used in the matrix operator theory are given. Results are obtained for multiple scattering in both homogeneous and inhomogeneous atmospheres. These results will be useful to researchers using the method since large savings in computer time and storage are obtainable.

POSTNATAL DISPOSITION OF TCDD IN LONG EVANS RATS FOLLOWING GESTATIONAL EXPOSURE

EPA Science Inventory

POSTNATAL DISPOSITION OF TCDD IN LONG EVANS RATS FOLLOWING GESTATIONAL EXPOSURE.
J J Diliberto', J T Hamm'.2, F McQuaid', and L S Birnbaum'. 'US EPA, ORD/NHEERL/ETD, RTP, NC; 2Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC.
2,3,7,8-Tetrachlorodibenz...

Exposure to the environmental endocrine disruptor TCDD and human reproductive dysfunction: Translating lessons from murine models.

PubMed

Bruner-Tran, Kaylon L; Gnecco, Juan; Ding, Tianbing; Glore, Dana R; Pensabene, Virginia; Osteen, Kevin G

2017-03-01

Humans and other animals are exposed to a wide array of man-made toxicants, many of which act as endocrine disruptors that exhibit differential effects across the lifespan. In humans, while the impact of adult exposure is known for some compounds, the potential consequences of developmental exposure to endocrine disrupting chemicals (EDCs) is more difficult to ascertain. Animal studies have revealed that exposure to EDCs prior to puberty can lead to adult reproductive disease and dysfunction. Specifically, in adult female mice with an early life exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), we demonstrated a transgenerational occurrence of several reproductive diseases that have been linked to endometriosis in women. Herein, we review the evidence for TCDD-associated development of adult reproductive disease as well as known epigenetic alterations associated with TCDD and/or endometriosis. We will also introduce new "Organ-on-Chip" models which, combined with our established murine model, are expected to further enhance our ability to examine alterations in gene-environment interactions that lead to heritable disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Exposure to the Environmental Endocrine Disruptor TCDD and Human Reproductive Dysfunction: Translating Lessons from Murine Models

PubMed Central

Bruner-Tran, Kaylon L.; Gnecco, Juan; Ding, Tianbing; Glore, Dana R.; Pensabene, Virginia; Osteen, Kevin G.

2016-01-01

Humans and other animals are exposed to a wide array of man-made toxicants, many of which act as endocrine disruptors that exhibit differential effects across the lifespan. In humans, while the impact of adult exposure is known for some compounds, the potential consequences of developmental exposure to endocrine disrupting chemicals (EDCs) is more difficult to ascertain. Animal studies have revealed that exposure to EDCs prior to puberty can lead to adult reproductive disease and dysfunction. Specifically, in adult female mice with an early life exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), we demonstrated a transgenerational occurrence of several reproductive diseases that have been linked to endometriosis in women. Herein, we review the evidence for TCDD-associated development of adult reproductive disease as well as known epigenetic alterations associated with TCDD and/or endometriosis. We will also introduce new “Organ-on-Chip” models which, combined with our established murine model, are expected to further enhance our ability to examine alterations in gene-environment interactions that lead to heritable disease. PMID:27423904

Dioxin (TCDD) Induces Epigenetic Transgenerational Inheritance of Adult Onset Disease and Sperm Epimutations

PubMed Central

Manikkam, Mohan; Tracey, Rebecca; Guerrero-Bosagna, Carlos; Skinner, Michael K.

2012-01-01

Environmental compounds can promote epigenetic transgenerational inheritance of adult-onset disease in subsequent generations following ancestral exposure during fetal gonadal sex determination. The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations. PMID:23049995

Adsorption of TCDD with 1-butyl-3-methylimidazolium dicyanamide ionic liquid: a combined molecular dynamics simulation and quantum chemistry study.

PubMed

Pan, Wenxiao; Qi, Yuanyuan; Wang, Ruoxi; Han, Zhe; Zhang, Dongju; Zhan, Jinhua

2013-04-01

The effective abatement of flue gas emissions, especially polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), is one of the challenging issues in the field of environmental science currently. Imidazolium-based dicyanamide ionic liquids (ILs) were proposed to have potential in controlling the emissions of PCDD/Fs. However, the relevant mechanism at the molecular level still remains unclear. To address this subject, we here present a combined molecular dynamics (MD) simulation and quantum chemical (QM) study on the adsorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener among PCDD/F family, by 1-butyl-3-methylimidazolium dicyanamide IL, a representative imidazolium dicyanoamide ILs, which were demonstrated to possess high capture capability for PCDD/Fs. The MD simulation results show that TCDD molecules can be effectively adsorbed on the IL surface to form a dense layer, but cannot enter the interior of the IL. The results of QM calculations show that the adsorption of TCDDs on the IL surface occurs via intra-molecular hydrogen bond interactions. The calculated interaction energy of the anion with TCDD molecule is two times more than that of the cation, implying that the IL anion dominates the interaction with TCDD molecules, while the cation plays a secondary role. Based on the calculated results, we propose that imidazolium dicyanamide IL films/membranes may be better materials than the corresponding bulk for capturing TCDD. The present theoretical results may be helpful to designing the functional ILs which effectively capture and concentrate PCDD/F compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

2,3,7,8-Tetrachlorodibenzo-p-dioxin induces apoptotic cell death and cytochrome P4501A expression in developing Fundulus heteroclitus embryos

USGS Publications Warehouse

Toomey, B.H.; Bello, S.; Hahn, M.E.; Cantrell, S.; Wright, P.; Tillitt, D.E.; Di Giulio, R.T.

2001-01-01

Fundulus heteroclitus embryos were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during early development using nanoinjection or water bath exposure. TCDD caused developmental abnormalities that included hemorrhaging, loss of vascular integrity, edema, stunted development and death. The LC50 and LD50 of TCDD for Fundulus embryos were ???19.7??9.5 pg TCDD/??l (water bath) and 0.25??0.09 ng TCDD/g embryo (nanoinjection). To identify a possible cause for these developmental abnormalities we analyzed the effects of TCDD on apoptotic cell death and cytochrome P4501A (CYP1A) expression in the embryos. TCDD exposure increased apoptotic cell death in several tissues including brain, eye, gill, kidney, tail, intestine, heart, and vascular tissue. CYP1A expression was also increased in the TCDD-exposed embryos predominantly in liver, kidney, gill, heart, intestine, and in vascular tissues throughout the embryo. There was co-occurrence of TCDD-induced apoptosis and CYP1A expression in some, but not all, cell types. In addition the dose response relationships for apoptosis and mortality were similar, while CYP1A expression appeared more sensitive to TCDD induction. Copyright ?? 2001 Elsevier Science B.V.

Comparative Analysis of AhR-Mediated TCDD-Elicited Gene Expression in Human Liver Adult Stem Cells

PubMed Central

Kim, Suntae; Dere, Edward; Burgoon, Lyle D.; Chang, Chia-Cheng; Zacharewski, Timothy R.

2009-01-01

Time course and dose-response studies were conducted in HL1-1 cells, a human liver cell line with stem cell–like characteristics, to assess the differential gene expression elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) compared with other established models. Cells were treated with 0.001, 0.01, 0.1, 1, 10, or 100nM TCDD or dimethyl sulfoxide vehicle control for 12 h for the dose-response study, or with 10nM TCDD or vehicle for 1, 2, 4, 8, 12, 24, or 48 h for the time course study. Elicited changes were monitored using a human cDNA microarray with 6995 represented genes. Empirical Bayes analysis identified 144 genes differentially expressed at one or more time points following treatment. Most genes exhibited dose-dependent responses including CYP1A1, CYP1B1, ALDH1A3, and SLC7A5 genes. Comparative analysis of HL1-1 differential gene expression to human HepG2 data identified 74 genes with comparable temporal expression profiles including 12 putative primary responses. HL1-1–specific changes were related to lipid metabolism and immune responses, consistent with effects elicited in vivo. Furthermore, comparative analysis of HL1-1 cells with mouse Hepa1c1c7 hepatoma cell lines and C57BL/6 hepatic tissue identified 18 and 32 commonly regulated orthologous genes, respectively, with functions associated with signal transduction, transcriptional regulation, metabolism and transport. Although some common pathways are affected, the results suggest that TCDD elicits species- and model-specific gene expression profiles. PMID:19684285

Role of the cyclooxygenase 2-thromboxane pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced decrease in mesencephalic vein blood flow in the zebrafish embryo

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

Teraoka, Hiroki; Kubota, Akira; Dong, Wu

2009-01-01

Previously, we reported that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) evoked developmental toxicity required activation of aryl hydrocarbon receptor type 2 (AHR2), using zebrafish embryos. However, the downstream molecular targets of AHR2 activation are largely unknown and are the focus of the present investigation. TCDD induces cyclooxygenase 2 (COX2), a rate-limiting enzyme for prostaglandin synthesis in certain cells. In the present study, we investigated the role of the COX2-thromboxane pathway in causing a specific endpoint of TCDD developmental toxicity in the zebrafish embryo, namely, a decrease in regional blood flow in the dorsal midbrain. It was found that the TCDD-induced reduction in mesencephalic veinmore » blood flow was markedly inhibited by selective COX2 inhibitors, NS-398 and SC-236, and by a general COX inhibitor, indomethacin, but not by a selective COX1 inhibitor, SC-560. Gene knock-down of COX2 by two different types of morpholino antisense oligonucleotides, but not by their negative homologs, also protected the zebrafish embryos from mesencephalic vein circulation failure caused by TCDD. This inhibitory effect of TCDD on regional blood flow in the dorsal midbrain was also blocked by selective antagonists of the thromboxane receptor (TP). Treatment of control zebrafish embryos with a TP agonist also caused a reduction in mesencephalic vein blood flow and it too was blocked by a TP antagonist, without any effect on trunk circulation. Finally, gene knock-down of thromboxane A synthase 1 (TBXS) with morpholinos but not by the morpholinos' negative homologs provided significant protection against TCDD-induced mesencephalic circulation failure. Taken together, these results point to a role of the prostanoid synthesis pathway via COX2-TBXS-TP in the local circulation failure induced by TCDD in the dorsal midbrain of the zebrafish embryo.« less

Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver.

PubMed

Amenya, Hesbon Z; Tohyama, Chiharu; Ohsako, Seiichiroh

2016-10-07

The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress.

Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

NASA Astrophysics Data System (ADS)

Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

2016-10-01

The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress.

Handler, bystander and reentry exposure to TCDD from application of Agent Orange by C-123 aircraft during the Vietnam War.

PubMed

Ross, John H; Hewitt, Andrew; Armitage, James; Solomon, Keith; Watkins, Deborah K; Ginevan, Michael E

2015-02-01

Using validated models and methods routinely employed by pesticide regulatory agencies, the absorbed dosages of Agent Orange (AO) herbicide contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were estimated for mixer/loaders, applicators, and individuals in the vicinity of applications of AO by C-123 aircraft during the Vietnam War. Resulting dosages of TCDD were then transformed to estimates of adipose residues, and compared to population biomonitoring of known mixer/loaders and applicators as well as ground troops in Vietnam and civilians in the U.S. Results demonstrate that mixer/loaders and applicators had the greatest exposures and their measured residues of TCDD in adipose were consistent with the estimated exposures. Further, the potentially exposed ground troops, including those who could have been directly sprayed during aerial defoliation, had measured adipose residues that were consistent with those in civilian U.S. populations with no defined source of exposure exposures and both of those cohorts had orders of magnitude less exposure than the mixer/loaders or applicators. Despite the availability of validated exposure modeling methods for decades, the quantitative TCDD dose estimates presented here are the first of their kind for the Vietnam conflict. Copyright © 2014 Elsevier B.V. All rights reserved.

Sex ratio of the offspring of Sprague-Dawley rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in utero and lactationally in a three-generation study

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

Rowlands, J.C.; Budinsky, R.A.; Aylward, L.L.

Reports of a decreased male/female sex ratio in children born to males exposed to TCDD in Seveso, Italy, at a young age have sparked examinations of this endpoint in other populations exposed to TCDD or related compounds. Overall, the male/female sex ratio results reported in these studies, with slightly different age-exposed male populations, have shown mixed results. Experimental studies of the effects of in utero exposure to TCDD in laboratory animals have reported no effect on the f{sub 1} sex ratio and mixed results for the sex ratio of the f{sub 2} generation. In order to better understand the potentialmore » effects of TCDD on second generation sex ratio, we retrieved archived data from a comprehensive three-generation feeding study of TCDD in rats that was conducted and published in the 1970s, but which did not publish data on sex ratio of the offspring [Murray, F.J., Smith, F.A., Nitschke, K.D., Humiston, C.G., Kociba, R.J., Schwetz, B.A., 1979. Three-generation reproduction study of rats given 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the diet. Toxicol. Appl. Pharmacol. 50, 241-252]. A re-examination of the original Murray et al. data found no statistically significant treatment-related changes in postnatal day 1 sex ratio in any generation of treated animals, consistent with one other relatively large study reporting on this endpoint. We discuss mechanistic data underlying a potential effect of TCDD on this endpoint. We conclude that the inconsistency in findings on sex ratio of the offspring of male rats exposed to TCDD in utero is likely due to random variation associated with a relatively small sample size, although differences between studies in strain of rat, dose regimen, and day of ascertainment of sex ratio cannot be ruled out.« less

COMPARING MIXTURES OF DIOXIN-LIKE AND NON DIOXIN-LIKE PCBS TO TCDD

EPA Science Inventory

COMPARING MIXTURES OF DIOXIN-LIKE AND NON DIOXIN-LIKE PCBS TO TCDD. D E Burgin1, J J Diliberto2 and L S Birnbaum3.1University of North Carolina/Toxicology, Chapel Hill, NC, USA; 2USEPA/ORD/NHEERL, ETD, Research Triangle Park, NC, USA; 3USEPA/ORD/NHEERL, HSD, Chapel Hill, NC, USA....

Exposure to TCDD from base perimeter application of Agent Orange in Vietnam.

PubMed

Ross, John H; Hewitt, Andrew; Armitage, James; Solomon, Keith; Watkins, Deborah K; Ginevan, Michael E

2015-04-01

Using recognized methods routinely employed by pesticide regulatory agencies, the exposures of military personnel that were mixer/loader/applicators (M/L/A) of Agent Orange (AO) for perimeter foliage at bases during the Vietnam War were estimated. From the fraction of TCDD in AO, absorbed dosage of the manufacturing contaminant was estimated. Dermal exposure estimated from spray drift to residents of the bases was calculated using internationally recognized software that accounted for proximity, foliar density of application site, droplet size and wind speed among other factors, and produced estimates of deposition. Those that directly handled AO generally had much higher exposures than those further from the areas of use. The differences in exposure potential varied by M/L/A activity, but were typically orders of magnitude greater than bystanders. However, even the most-exposed M/L/A involved in perimeter application had lifetime exposures comparable to persons living in the U.S. at the time, i.e., ~1.3 to 5 pg TCDD/kg bodyweight. Copyright © 2014 Elsevier B.V. All rights reserved.

2,3,7, 8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)-MEDIATED OXIDATIVE STRESS IN FEMALE CYP1A-2 KNOCKOUT (CYP1A2-/-) MICE

EPA Science Inventory

2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD)-Mediated Oxidative Stress in Female CYP1A2 Knockout (CYP1A2-/-) Mice

Deborah Burgin1, Janet Diliberto2, Linda Birnbaum2
1UNC Toxicology; 2USEPA/ORD/NHEERL, RTP, NC

Most of the effects due to TCDD exposure are mediated via...

Long overlooked historical information on Agent Orange and TCDD following massive applications of 2,4,5-T-containing herbicides, Eglin Air Force Base, Florida.

PubMed

Young, Alvin L; Newton, Michael

2004-01-01

From 1961-1971, The Air Development Test Center, Eglin Air Force Base (AFB), Florida, developed, tested, and calibrated the aerial spray systems used in support of Operation RANCH HAND and the US Army Chemical Corps in Vietnam. Twenty major test and evaluation projects of aerial spray equipment were conducted on four fully instrumented test grids, each uniquely arrayed to match the needs of fixed-wing, helicopter, or jet aircraft. Each of the grids was established within the boundary of Test Area 52A of the Eglin Reservation. The tests, conducted under climatic and environmental conditions similar to those in Vietnam, included the use of the military herbicides (Agents) Orange, Purple, White, and Blue. Approximately 75,000 kg of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 76,000 kg of 2,4-dichlorophenoxyacetic acid (2,4-D) were aerially disseminated on an area of less than 3 km2 during the period 1962-1970. Data from the analysis of archived samples suggested that an estimated 3.1 kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), present as a contaminant, were aerially released in the test area. Because most of the vegetation had been removed before establishing the test site in 1961, there was an opportunity to follow ground-based residues independent of canopy interception, and the resulting high solar exposure of initial residues. Studies of the soils, fauna, flora, and aquatic ecosystems of the test grids and associated perimeters of Test Area C-52A (an area totally more than 8 km2) were initiated in 1969 and concluded in 1984. Data from soil samples collected from 1974 through 1984 suggested that less than one percent of the TCDD that was present in soil when sampling began persisted through the ten-year period of sampling. More than 340 species of organisms were observed and identified within the test area. More than 300 biological samples were analyzed for TCDD and detectable residues were found in 16 of 45 species examined. Examination of the ecological

A Mouse Strain Less Responsive to Dioxin-Induced Prostaglandin E2 Synthesis Is Resistant to the Onset of Neonatal Hydronephrosis

PubMed Central

Kawaguchi, Tatsuya; Ohsako, Seiichiroh; Tohyama, Chiharu

2014-01-01

Dioxin is a ubiquitous environmental pollutant that induces toxicity when bound to the aryl hydrocarbon receptor (AhR). Significant differences in susceptibility of mouse strains to dioxin toxicity are largely accounted for by the dissociation constant of binding to dioxins of AhR subtypes encoded by different alleles. We showed that cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1), components of a prostanoid synthesis pathway, play essential roles in the onset of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced hydronephrosis of neonatal mice. Although C57BL/6J and BALB/cA mice harbor AhR receptors highly responsive to TCDD, they were found by chance to differ significantly in the incidence of TCDD-induced hydronephrosis. Therefore, the goal of the present study was to determine the molecular basis of this difference in susceptibility to TCDD toxicity. For this purpose, we administered C57BL/6J and BALB/cA dams’ TCDD at an oral dose of 15 or 80 μg/kg on postnatal day (PND) 1 to expose pups to TCDD via lactation, and the pups’ kidneys were collected on PND 7. The incidence of hydronephrosis in C57BL/6J pups (64%) was greater than in BALB/cA pups (0%, p < 0.05), despite similarly increased levels of COX-2 mRNA. The incidence of hydronephrosis in these mouse strains paralleled the levels of renal mPGES-1 mRNA and early growth response 1 (Egr-1) that modulates mPGES-1 gene expression, as well as PGE2 concentrations in urine. Although these mouse strains possess AhR alleles tightly bound to TCDD, their difference in incidence and severity of hydronephrosis can be explained, in part, by differences in the expression of mPGES-1 and Egr-1. PMID:25015655

Metabolomics identifies an inflammatory cascade involved in dioxin- and diet-induced steatohepatitis

PubMed Central

Matsubara, Tsutomu; Tanaka, Naoki; Krausz, Kristopher W.; Manna, Soumen K.; Kang, Dong Wook; Anderson, Erik R.; Luecke, Hans; Patterson, Andrew D.; Shah, Yatrik M.; Gonzalez, Frank J.

2012-01-01

Summary 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is among the most potent environmentally toxic compounds. Serum metabolomics identified azelaic acid-mono esters as significantly increased metabolites after TCDD treatment, due to down-regulation of hepatic carboxylesterase 3 (CES3, also known as triglyceride hydrolase) expression in an arylhydrocarbon receptor (AhR)-dependent manner in mice. The decreased CES3 expression was accomplished by TCDD-stimulated TGFβ-SMAD3 and IL6-STAT3 signaling, but not by direct AhR signaling. Methionine- and choline-deficient (MCD) diet-treated mice also showed enhanced serum azelaic acid-mono ester levels following attenuation of hepatic CES3 expression, while db/db mice did not, thus suggesting an association with steatohepatitis. Forced expression of CES3 reversed serum azelaic acid-mono ester/azelaic acid ratios and hepatic TGFβ mRNA levels in TCDD- and MCD diet-treated mice and ameliorated steatohepatitis induced by MCD diet. These results support the view that azelaic acid-mono esters are possible indicators of TCDD exposure and steatohepatitis, and suggest a link between CES3, TGFβ, and steatohepatitis. PMID:23140643

Mechanisms of Cellular Membrane Effects of TCDD (2,3,7,8-Tetrachlorodibenzo-p-Dioxin) Selected Perfluorinated Acids and Polyhalogenated Aromatic Hydrocarbons.

DTIC Science & Technology

1986-10-15

tetrachloro dibenzo-p-dioxin (TCDD); dioxin; perfluoro -n-decanoic acid ( PFDA ); perfluoro -n-octanoic acid ( PFOA ); 3,31,4,41,5,51 hexachlorobiphenyl (345PCB) and...analysis of livers from rats treated with perfluoro -n-decanoic acid ( PFDA ) showed a decrease in stearic acid and an increase in 18 carbon unsaturates...effects of TCDD, PHAH and perfluorinated acids ( PFA ) on mammalian cell membrane function by examing the phenomenon of metabolic cooperation. Metabolic

Interactive effects of n-TiO2 and 2,3,7,8-TCDD on the marine bivalve Mytilus galloprovincialis.

PubMed

Canesi, Laura; Frenzilli, Giada; Balbi, Teresa; Bernardeschi, Margherita; Ciacci, Caterina; Corsolini, Simonetta; Della Torre, Camilla; Fabbri, Rita; Faleri, Claudia; Focardi, Silvano; Guidi, Patrizia; Kočan, Anton; Marcomini, Antonio; Mariottini, Michela; Nigro, Marco; Pozo-Gallardo, Karla; Rocco, Lucia; Scarcelli, Vittoria; Smerilli, Arianna; Corsi, Ilaria

2014-08-01

Despite the growing concern over the potential biological impact of nanoparticles (NPs) in the aquatic environment, little is known about their interactions with other pollutants. The bivalve Mytilus sp, largely utilized as a sentinel for marine contamination, has been shown to represent a significant target for different types of NP, including n-TiO2, one of the most widespread in use. In this work, the possible interactive effects of n-TiO2 and 2,3,7,8-TCDD, chosen as models of NP and organic contaminant, respectively, were investigated in Mytilus galloprovincialis. In vitro experiments with n-TiO2 and TCDD, alone and in combination, were carried out in different conditions (concentrations and times of exposure), depending on the target (hemocytes, gill cells and biopsies) and the endpoint measured. Mussels were also exposed in vivo to n-TiO2 (100 μg L(-1)) or to TCDD (0.25 μg L(-1)), alone and in combination, for 96 h. A wide range of biomarkers, from molecular to tissue level, were measured: lysosomal membrane stability and phagocytosis in hemocytes, ATP-binding cassette efflux transporters in gills (gene transcription and efflux activity), several biomarkers of genotoxicity in gill and digestive cells (DNA damage, random amplified polymorphic DNA-RAPD changes), lysosomal biomarkers and transcription of selected genes in the digestive gland. The results demonstrate that n-TiO2 and TCDD can exert synergistic or antagonistic effects, depending on experimental condition, cell/tissue and type of measured response. Some of these interactions may result from a significant increase in TCDD accumulation in whole mussel organisms in the presence of n-TiO2, indicating a Trojan horse effect. The results represent the most extensive data obtained so far on the sub-lethal effects of NPs and organic contaminants in aquatic organisms. Moreover, these data extend the knowledge on the molecular and cellular targets of NPs in bivalves. Copyright © 2013 Elsevier B.V. All

Modulation of ovarian follicle maturation and effects on apoptotic cell death in Holtzman rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in utero and lactationally.

PubMed

Heimler, I; Trewin, A L; Chaffin, C L; Rawlins, R G; Hutz, R J

1998-01-01

Recent reports have described the reproduction-modulating and endocrine-disrupting effects following exposure to toxic substances such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Herein, we set out (1) to determine whether TCDD exposure exerts detrimental effects on follicle maturation in the Holtzman rat ovary and (2) to determine whether the effects of TCDD are mediated in part via apoptotic cell death. In certain species, dioxin exposure is correlated with reduced fecundity, reduced ovulatory rate, an increased incidence of endometriosis, and various reproductive cancers. Although some of the effects of TCDD are mediated via the hypothalamic-pituitary axis, direct effects on the ovary have also been observed. In the present study, an oral dose of 1 microgram TCDD/kg maternal body weight was administered on Day 15 of gestation. Female pups were sacrificed on Postnatal Day 21/22, and the ovaries were excised, fixed for histologic analysis, and analyzed in a double-blind paradigm. The analysis included a count and measurement and classification of preantral and antral follicles throughout the entire ovary. The contralateral ovary from each animal was analyzed for DNA fragmentation indicative of apoptotic cell death. The results indicate that TCDD treatment significantly reduced the number of antral follicles in the size classes 50,000 to 74,999 microns2 and > 100,000 microns2. We also observed a reduction in the number of preantral follicles less than 50,000 microns2. No difference was observed in the degree of apoptotic cell death in antral (50,000 to > 100,000 microns2) and preantral follicles (50,000 microns2 to > 75,000 microns2) between TCDD-treated and control-treated tissues. These data support the hypothesis that TCDD results in a diminution in the number of antral and preantral follicles of certain size classes in animals exposed during critical periods of development, but that apoptosis does not appear to be the underlying mechanism in these particular

Environmental fate and dietary exposures of humans to TCDD as a result of the spraying of Agent Orange in upland forests of Vietnam.

PubMed

Armitage, James M; Ginevan, Michael E; Hewitt, Andrew; Ross, John H; Watkins, Deborah K; Solomon, Keith R

2015-02-15

The fate and transport of 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD) released into the environment of South Vietnam (SVN) as a consequence of the aerial application of the herbicidal defoliant Agent Orange (AO) were simulated for a generic upland forest scenario and followed over a 50-year period (1965, 1968 and 1970 onwards). Modeled concentrations of TCDD in the environment were then used as inputs to a human exposure model, which focused on long-term exposures via the food chain. Intake rates and body burdens of TCDD were estimated for adult males over the course of the simulation period and compared to available biomonitoring data. One of the most important factors determining the magnitude of the simulated human exposure to TCDD was the fraction of the chemical deposited directly to soil (where it was assumed to have a degradation half-life of 10 or 15years) relative to the fraction assumed to remain on/in the forest canopy following the spray application (where it was assumed to have a degradation half-life of ≤48h). The simulated body burdens under the various scenarios considered were broadly consistent with the biomonitoring data from SVN collected in the mid-1980s to late 1990s. Taken together, the modeling results and empirical data suggest that highly elevated exposures to TCDD (i.e., body burdens in the several 100s of pg/g lipid range and greater) were not common among people inhabiting upland forest locations in SVN sprayed with AO and that peak and average body burdens were broadly similar to those of the general population of the U.S. in the 1970s and early 1980s. The model-based assessment is consistent with the 'hot spot' hypothesis i.e., potential exposures to TCDD linked to activities conducted on or near former bases where AO was stored are greater than potential exposures in areas subjected to aerial spraying. Copyright © 2014 Elsevier B.V. All rights reserved.

The aryl hydrocarbon receptor (AhR) mediates resistance to apoptosis induced in breast cancer cells.

PubMed

Bekki, Kanae; Vogel, Helena; Li, Wen; Ito, Tomohiro; Sweeney, Colleen; Haarmann-Stemmann, Thomas; Matsumura, Fumio; Vogel, Christoph F A

2015-05-01

The aryl hydrocarbon receptor (AhR) is well known as a ligand binding transcription factor regulating various biological effects. Previously we have shown that long-term exposure to estrogen in breast cancer cells caused not only down regulation of estrogen receptor (ER) but also overexpression of AhR. The AhR interacts with several cell signaling pathways associated with induction of tyrosine kinases, cytokines and growth factors which may support the survival roles of AhR escaping from apoptosis elicited by a variety of apoptosis inducing agents in breast cancer. In this study, we studied the anti-apoptotic role of AhR in different breast cancer cells when apoptosis was induced by exposure to UV light and chemotherapeutic agents. Activation of AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in AhR overexpressing breast cancer cells effectively suppressed the apoptotic response induced by UV-irradiation, doxorubicin, lapatinib and paclitaxel. The anti-apoptotic response of TCDD was uniformly antagonized by the treatment with 3'methoxy-4'nitroflavone (MNF), a specific antagonist of AhR. TCDD's survival action of apoptosis was accompanied with the induction of well-known inflammatory genes, such as cyclooxygenase-2 (COX-2) and NF-κB subunit RelB. Moreover, TCDD increased the activity of the immunosuppressive enzyme indoleamine 2, 3-dioxygenase (IDO), which metabolizes tryptophan to kynurenine (Kyn) and mediates tumor immunity. Kyn also acts as an AhR ligand like TCDD, and kyn induced an anti-apoptotic response in breast cancer cells. Accordingly, our present study suggests that AhR plays a pivotal role in the development of breast cancer via the suppression of apoptosis, and provides an idea that the use of AhR antagonists with chemotherapeutic agents may effectively synergize the elimination of breast cancer cells. Copyright © 2014 Elsevier Inc. All rights reserved.

EXPRESSION OF AHR AND ARNT MRNA IN CULTURED HUMAN ENDOMETRIAL EXPLANTS EXPOSED TO TCDD

EPA Science Inventory

Expression of AhR and ARNT mRNA in cultured human endometrial explants exposed to TCDD.

Pitt JA, Feng L, Abbott BD, Schmid J, Batt RE, Costich TG, Koury ST, Bofinger DP.

Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC 27599, USA.

Endom...

A mouse strain less responsive to dioxin-induced prostaglandin E2 synthesis is resistant to the onset of neonatal hydronephrosis.

PubMed

Aida-Yasuoka, Keiko; Yoshioka, Wataru; Kawaguchi, Tatsuya; Ohsako, Seiichiroh; Tohyama, Chiharu

2014-10-01

Dioxin is a ubiquitous environmental pollutant that induces toxicity when bound to the aryl hydrocarbon receptor (AhR). Significant differences in susceptibility of mouse strains to dioxin toxicity are largely accounted for by the dissociation constant of binding to dioxins of AhR subtypes encoded by different alleles. We showed that cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1), components of a prostanoid synthesis pathway, play essential roles in the onset of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced hydronephrosis of neonatal mice. Although C57BL/6J and BALB/cA mice harbor AhR receptors highly responsive to TCDD, they were found by chance to differ significantly in the incidence of TCDD-induced hydronephrosis. Therefore, the goal of the present study was to determine the molecular basis of this difference in susceptibility to TCDD toxicity. For this purpose, we administered C57BL/6J and BALB/cA dams' TCDD at an oral dose of 15 or 80 μg/kg on postnatal day (PND) 1 to expose pups to TCDD via lactation, and the pups' kidneys were collected on PND 7. The incidence of hydronephrosis in C57BL/6J pups (64%) was greater than in BALB/cA pups (0%, p < 0.05), despite similarly increased levels of COX-2 mRNA. The incidence of hydronephrosis in these mouse strains paralleled the levels of renal mPGES-1 mRNA and early growth response 1 (Egr-1) that modulates mPGES-1 gene expression, as well as PGE2 concentrations in urine. Although these mouse strains possess AhR alleles tightly bound to TCDD, their difference in incidence and severity of hydronephrosis can be explained, in part, by differences in the expression of mPGES-1 and Egr-1. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Peroxiredoxin I protein, a potential biomarker of hydronephrosis in fetal mice exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

PubMed

Liu, Mingxue; Liu, Jing; Liu, Xing; Wei, Guanghui

2014-06-01

In previous studies, we established an animal model of human congenital hydronephrosis with exposure of developing mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), but the etiopathogenesis is not entirely clear. The present study was to identify the changes that may be involved in the etiology at the protein level. C57BL/6J mice fetuses were treated with TCDD. Comparative proteomic analysis was adopted to identify the proteins associated with hydronephrosis induced by TCDD. Two-dimensional electrophoresis display revealed that 19 protein spots were differentially expressed in the upper urinary tract tissues in fetal mice after exposure to TCDD. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) identified 12 up-regulated proteins: peroxiredoxin I (Prx I), cadherin 6, gamma-actin, radixin, desmin, type II transforming growth factor-beta receptor, chromogranin B, serum albumin precursor, transferrin, hypothetical protein LOC70984, lipk protein, and zinc finger protein 336. Histochemical staining indicated that Prx I protein was positively expressed in the ureteric epithelium in the treated group, and not in the control group, which is consistent with MALDI-TOF-MS. Prx I protein may be a potential biomarker or responsive protein of hydronephrosis in fetal mice induced by TCDD. Copyright © 2013 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

4-Methoxyestradiol-induced oxidative injuries in human lung epithelial cells

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

Cheng Yahsin; Chang, Louis W.; Cheng Lichuan

2007-05-01

Epidemiological studies indicated that people exposed to dioxins were prone to the development of lung diseases including lung cancer. Animal studies demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increased liver tumors and promoted lung metaplasia in females. Metabolic changes in 17{beta}-estradiol (E{sub 2}) resulted from an interaction between TCDD and E{sub 2} could be associated with gender difference. Previously, we reported that methoxylestradiols (MeOE{sub 2}), especially 4-MeOE{sub 2}, accumulated in human lung cells (BEAS-2B) co-treated with TCDD and E{sub 2}. In the present study, we demonstrate unique accumulation of 4-MeOE{sub 2}, as a result of TCDD/E{sub 2} interaction and revealed its bioactivity inmore » human lung epithelial cell line (H1355). 4-Methoxyestradiol treatment significantly decreased cell growth and increased mitotic index. Elevation of ROS and SOD activity, with a concomitant decrease in the intracellular GSH/GSSG ratio, was also detected in 4-MeOE{sub 2}-treated cells. Quantitative comet assay showed increased oxidative DNA damage in the 4-MeOE{sub 2}-treated H1355 cells, which could be significantly reduced by the anti-oxidant N-acetylcysteine (NAC). However, inhibition of cell growth and increase in mitotic arrest induced by 4-MeOE{sub 2} were unaffected by NAC. We concluded that 4-MeOE{sub 2} accumulation resulting from TCDD and E{sub 2} interaction would contribute to the higher vulnerability on lung pathogenesis in females when exposed to TCDD.« less

COMPARING ENVIRONMENTALLY RELEVANT PCBS TO TCDD IN CYP1A2 NULL AND WILDTYPE MICE

EPA Science Inventory

The role of CYP1A2 on the interactions of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, dioxin), dioxin-like (DL) and non-dioxin-like (NDL) polychlorinated biphenyls (PCBs) was compared in multiple responses of different laboratory-defined mixtures, based on mass ratios found in...

Comparison of the in vitro effects of TCDD, PCB 126 and PCB 153 on thyroid-restricted gene expression and thyroid hormone secretion by the chicken thyroid gland.

PubMed

Katarzyńska, Dorota; Hrabia, Anna; Kowalik, Kinga; Sechman, Andrzej

2015-03-01

The aim of this study was to compare the in vitro effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4',5-pentachlorobiphenyl (PCB 126; a coplanar PCB congener) and 2,2'4,4',5,5'-hexachlorobiphenyl (PCB153; non-coplanar PCB) on mRNA expression of thyroid-restricted genes, i.e. sodium iodide symporter (NIS), thyroid peroxidase (TPO) and thyroglobulin (TG), and thyroid hormone secretion from the thyroid gland of the laying chicken. Relative expression levels of NIS, TG and TPO genes and thyroxine (T4) and triiodothyronine (T3) secretion from the thyroidal explants were quantified by the real-time qPCR and RIA methods, respectively. In comparison with the control group, TCDD and PCB 126 significantly increased mRNA expression of TPO and TG genes. TCDD did not affect NIS mRNA levels, but PCB 126 decreased its expression. No effect of PCB 153 on the expression of these genes was observed. TCDD and PCB 126 significantly decreased T4 and T3 secretion. There was no significant effect of PCB 153 on these hormone secretions. In conclusion, the results obtained show that in comparison with non-coplanar PCB 153, TCDD and coplanar PCB 126 can directly affect thyroid hormone synthesis and secretion, and in consequence, they may disrupt the endocrine function of the thyroid gland of the laying chicken. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of PFDA (Perfluoro-n-Decanoic Acid) and TCDD on Heart Membranes.

DTIC Science & Technology

1986-06-18

AD-A171 960 COMPARISON OF PFDA ( PERFLUORO -N-DECANOIC ACID) AND TCDD 1/1 ON HEART NEMBRANES(U) WRIGHT STATE UNIY DAYTON OH SCHOOL OF MEDICINE A E...1986) Toxicol. Appl. Pharmacol. Perfluoro -n-decanoic acid ( PFDA ) is a synthetic chemical resembling a 10 carbon fatty acid. Several studies have...3 INTRODUCTION Perfluoro -n-decanoic acid ( PFDA ; nonadecafluorodecanoic acid, C10 F19 0 2H) is a straight-chain 10 carbon carboxylic acid with fluorine

ADVERSE EFFECTS OF TCDD ON MAMMARY GLAND DEVELOPMENT IN LONG EVANS RATS: A TWO GENERATIONAL STUDY

EPA Science Inventory

Recent studies have demonstrated variable effects on mammary gland development in rat offspring exposed to TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, 1 ug/kg, gavage) on day 15 of gestation. We have characterized these effects in Long Evans rats, in both one and two-generational...

Molokhia (Corchorus olitorius L.) extract suppresses transformation of the aryl hydrocarbon receptor induced by dioxins.

PubMed

Nishiumi, Shin; Yabushita, Yoshiyuki; Fukuda, Itsuko; Mukai, Rie; Yoshida, Ken-Ichi; Ashida, Hitoshi

2006-02-01

Dioxins enter the body mainly through diet and cause the various toxicological effects by binding to the cytosolic aryl hydrocarbon receptor (AhR) followed by its transformation. In recent reports, it has been shown that certain natural compounds suppress AhR transformation in vitro. In this study, we demonstrated that ethanolic extract from molokhia, known as Egyptian spinach, showed the strongest suppressive effect on AhR transformation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in cell-free system using rat hepatic cytosol among 41 kinds of extracts from vegetables and fruits. The molokhia extract also suppressed TCDD-induced AhR transformation in mouse hepatoma Hepa-1c1c7 cells and in intestinal permeability system constructed with human colon adenocarcinoma Caco-2 cells and human hepatoma HepG2 cells. Moreover, oral administration of the molokhia extract (100mg/kg body weight) decreased 3-methylcholanthrene-induced AhR transformation to the control level by inhibiting translocation of the AhR from cytosol into the nucleus in the liver of rats. The molokhia extract-administered rat liver showed a tolerance to TCDD-induced AhR transformation by ex vivo experiment. These results indicate that molokhia is an attractive food for isolation and identification of a natural antagonist for the AhR.

INFLUENCE OF TYPE II DIABETES AND OBESITY ON THE DISPOSITION AND ELIMINATION OF TCDD IN MICE

EPA Science Inventory

INFLUENCE OF TYPE II DIABETES AND OBESITY ON THE DISPOSTION AND ELIMINATION OF TCDD IN MICE. MJ DeVito', JJ Diliberto', DG Ross', C Emond2, VM Richardson', and LS Birnbaum', 'ETD, NHEERL, ORD, US EPA, RTP, NC, 27711, USA, 2National Research Council.
One possible explanation fo...

The effect of dose on 2,3,7,8-TCDD tissue distribution, metabolism and elimination in CYP1A2(-/_) knockout and C57BL/6N parental strains of mice

EPA Science Inventory

Numerous metabolism studies have demonstrated that the toxic contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is poorly metabolized. A hallmark feature of TCDD exposure is induction of hepatic CYP1A2 and subsequent sequestration leading to high liver-to-fat concentration ra...

Compound- and sex-specific effects on programming of energy and immune homeostasis in adult C57BL/6JxFVB mice after perinatal TCDD and PCB 153

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

Esterik, J.C.J. van, E-mail: joantine.van.esterik@rivm.nl; Department of Chemistry and Biology, Institute for Environmental Studies; Verharen, H.W., E-mail: henny.verharen@rivm.nl

Early life exposure to endocrine disrupting compounds has been linked to chronic diseases later in life, like obesity and related metabolic disorders. We exposed C57BL/6JxFVB hybrid mice to the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the constitutive androstane receptor/pregnane X receptor agonist polychlorinated biphenyl 153 (PCB 153) in an experimental design relevant for human exposure. Exposure occurred during gestation and lactation via maternal feed to a wide dose range (TCDD: 10–10,000 pg/kg body weight/day; PCB 153: 0.09–1406 μg/kg body weight/d). Then exposure was ceased and offspring were followed up to 1 year of age. Metabolic parameters like body weight,more » fat pad weights, glucose tolerance, endocrine serum profile, and neurobehavioral and immunological parameters were determined. Body weight was transiently affected by both compounds throughout the follow-up. TCDD-exposed males showed decreased fat pad and spleen weights and an increase in IL-4 production of splenic immune cells. In contrast, females showed increased fat pad weights and production of IFNγ. PCB 153-exposed males showed an increase in glucose, whereas females showed an increase in glucagon, a decrease in pancreas weight, and an increase in thymus weight. In conclusion, early life exposure to TCDD appears to affect programming of energy and immune homeostasis in offspring, whereas the effects of perinatal PCB 153 were mainly on programming of glucose homeostasis. Both compounds act sex-specifically. Lowest derived BMDLs (lower bounds of the (two sided) 90%-confidence interval for the benchmark dose) for both compounds are not lower than current tolerable daily intakes. - Highlights: • Early life exposure to TCDD affects programming of energy and immune homeostasis. • Early life exposure to PCB 153 affects programming of energy homeostasis. • Both compounds act sex-specifically. • Lowest derived BMDLs for both TCDD and PCB 153

Percutaneous Absorption of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (TCDD) From Soil (Journal Article)

EPA Science Inventory

Eight dermal absorption (two in vivo; six in vitro) and one intravenous experiment were conducted using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) either neat (high dose at ~250 µg/cm2 and low dose at 10 ng/cm2) or sorbed on a low organic (LOS) or high organic (HOS) soil at 1 ppm...

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

Cheng, Xingguo, E-mail: chengx@stjohns.edu; Vispute, Saurabh G.; Liu, Jie

The toxic effects of dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mainly through activation of the aryl hydrocarbon receptor (AhR) are well documented. Fibroblast growth factor (Fgf) 21 plays critical roles in metabolic adaptation to fasting by increasing lipid oxidation and ketogenesis in the liver. The present study was performed to determine whether activation of the AhR induces Fgf21 expression. In mouse liver, TCDD increased Fgf21 mRNA in both dose- and time-dependent manners. In addition, TCDD markedly increased Fgf21 mRNA expression in cultured mouse and human hepatocytes. Moreover, TCDD increased mRNA (in liver) and protein levels (in both liver and serum) ofmore » Fgf21 in wild-type mice, but not in AhR-null mice. Chromatin immunoprecipitation assays showed that TCDD increased AhR protein binding to the Fgf21 promoter (− 105/+ 1 base pair). Fgf21-null mice administered 200 μg/kg of TCDD died within 20 days, whereas wild-type mice receiving the same treatment were still alive at one month after administration. This indicates that TCDD-induced Fgf21 expression protects against TCDD toxicity. Diethylhexylphthalate (DEHP) pretreatment attenuated TCDD-induced Fgf21 expression in mouse liver and white adipose tissue, which may explain a previous report that DEHP pretreatment decreases TCDD-induced wasting. In conclusion, Fgf21 appears to be a target gene of AhR-signaling pathway in mouse and human liver. - Highlights: • TCDD induced Fgf21 expression at both mRNA and protein levels. • Fgf21 induction by TCDD is AhR-dependent. • DEHP attenuated TCDD-induced Fgf21 expression.« less

Deformities, PCBs, and TCDD-equivalents in double-crested cormorants (Phalacrocorax auritus) and Caspian terns (Hydroprogne caspia) of the Upper Great Lakes 1986–1991: Testing a cause-effect hypothesis

USGS Publications Warehouse

Ludwig, James P.; Kurita-Matsuba, Hiroko; Auman, Heidi J.; Ludwig, Matthew E.; Summer, Cheryl L.; Giesy, John P.; Tillitt, Donald E.; Jones, Paul D.

1996-01-01

Deformities have been reported in many species of colonial waterbirds from several localities on the Laurentian Great Lakes. The hypothesis that deformities were caused by either polychlorinated biphenyls (PCBs) or contaminants measured as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQs) is tested in this review of available data on concentrations of contaminants in eggs and observed deformities in embryos and chicks of double-crested cormorants (Phalacrocorax auritus) and Caspian terns (Hydroprogne caspia) between 1986 and 1991. Hatched chicks, live and dead eggs retrieved from 37 colonies in the upper Great Lakes were assessed for gross anatomical deformities. Rates of embryo death from seven regions of the upper Great Lakes were measured annually between 1986–1991. Half the embryos found dead in eggs were deformed. Nineteen types of abnormalities or deformities were observed. Subcutaneous edema in cormorants and gastroschisis in terns were the most common abnormalities in live or dead eggs. One of ten crossed-billed cormorant embryos survived to hatch. No bill-deformed terns hatched, although tern embryos had a greater rate of crossed-bills than cormorants. The suite of deformities and abnormalities found was similar to that produced in chickens by exposure to planar polychlorinated biphenyl (pPCB) and dioxin congeners. Hatching and deformity rates were correlated with concentrations ofpPCBs and TCDD-EQs. Planar PCB congeners that contributed most of the TCDD-EQs were present at concentrations sufficient to cause the observed effects. TCDD-EQs measured by H4IIE rat hepatoma cell 7-ethoxyresorufin O-deethylase (EROD) bioassay were highly correlated with deformity rates observed in cormorant chicks, live and dead eggs, and egg death rates. Similar correlations of TCDD-EQs with deformity rates were found in hatched tern chicks, dead eggs, and egg death rates, but not in live eggs. TCDD-EQs were more highly correlated to deformity and embryo death rates

The Effect of Dose on 2,3,7,8-TCDD Tissue Distribution, Metabolism and Elimination in CYP1A2 (-/-) Knockout and C57BL/6N Parental Strains of Mice

USDA-ARS?s Scientific Manuscript database

Numerous metabolism studies have demonstrated that the highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is poorly metabolized. A hallmark feature of TCDD exposure is induction of hepatic CYP1A2 and subsequent sequestration leading to high liver to fat concentration ratios. This study was in...

Effects of freezing-induced cell-fluid-matrix interactions on the cells and extracellular matrix of engineered tissues.

PubMed

Teo, Ka Yaw; DeHoyos, Tenok O; Dutton, J Craig; Grinnell, Frederick; Han, Bumsoo

2011-08-01

The two most significant challenges for successful cryopreservation of engineered tissues (ETs) are preserving tissue functionality and controlling highly tissue-type dependent preservation outcomes. In order to address these challenges, freezing-induced cell-fluid-matrix interactions should be understood, which determine the post-thaw cell viability and extracellular matrix (ECM) microstructure. However, the current understanding of this tissue-level biophysical interaction is still limited. In this study, freezing-induced cell-fluid-matrix interactions and their impact on the cells and ECM microstructure of ETs were investigated using dermal equivalents as a model ET. The dermal equivalents were constructed by seeding human dermal fibroblasts in type I collagen matrices with varying cell seeding density and collagen concentration. While these dermal equivalents underwent an identical freeze/thaw condition, their spatiotemporal deformation during freezing, post-thaw ECM microstructure, and cellular level cryoresponse were characterized. The results showed that the extent and characteristics of freezing-induced deformation were significantly different among the experimental groups, and the ETs with denser ECM microstructure experienced a larger deformation. The magnitude of the deformation was well correlated to the post-thaw ECM structure, suggesting that the freezing-induced deformation is a good indicator of post-thaw ECM structure. A significant difference in the extent of cellular injury was also noted among the experimental groups, and it depended on the extent of freezing-induced deformation of the ETs and the initial cytoskeleton organization. These results suggest that the cells have been subjected to mechanical insult due to the freezing-induced deformation as well as thermal insult. These findings provide insight on tissue-type dependent cryopreservation outcomes, and can help to design and modify cryopreservation protocols for new types of tissues from

Aryl hydrocarbon receptor suppresses the osteogenesis of mesenchymal stem cells in collagen-induced arthritic mice through the inhibition of β-catenin

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

Tong, Yulong; Niu, Menglin; Department of Blood Transfusion, Peking University Cancer Hospital & Institute, No. 52 Fucheng Rd., Beijing 100142

The contributions of aryl hydrocarbon receptor (Ahr) to the pathogenesis of rheumatoid arthritis (RA), particularly bone loss, have not been clearly explored. The imbalance between osteoblasts and osteoclasts is a major reason for bone loss. The dysfunction of osteoblasts, which are derived from mesenchymal stem cells (MSCs), induced bone erosion occurs earlier and is characterized as more insidious. Here, we showed that the nuclear expression and translocation of Ahr were both significantly increased in MSCs from collagen-induced arthritis (CIA) mice. The enhanced Ahr suppressed the mRNA levels of osteoblastic markers including Alkaline phosphatase (Alp) and Runt-related transcription factor 2 (Runx2)more » in the differentiation of MSCs to osteoblasts in CIA. The 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated activation of Ahr dose-dependently suppressed the expression of osteoblastic markers. In addition, the expression of β-catenin was reduced in CIA MSCs compared with control, and the TCDD-mediated activation of the Ahr significantly inhibited β-catenin expression. The Wnt3a-induced the activation of Wnt/β-catenin pathway partly rescued the osteogenesis decline induced by TCDD. Taken together, these results indicate that activated Ahr plays a negative role in CIA MSCs osteogenesis, possibly by suppressing the expression of β-catenin. - Highlights: • The Ahr pathway displays an activated profile in CIA MSCs. • The activation of Ahr suppresses osteogenesis in CIA MSCs. • TCDD suppresses osteogenesis in a dose-dependent manner. • The activation of Ahr inhibits β-catenin expression to exacerbate bone erosion.« less

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

Fullerton, Aaron M., E-mail: fuller22@msu.edu; Roth, Robert A., E-mail: rothr@msu.edu; Ganey, Patricia E., E-mail: ganey@msu.edu

Inflammation plays a major role in immune-mediated liver injury, and exposure to environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been reported to alter the inflammatory response as well as affect immune cell activity. In this study, we tested the hypothesis that TCDD pretreatment exacerbates hepatotoxicity in a murine model of immune-mediated liver injury induced by concanavalin A (Con A) administration. Mice were pretreated with 30 μg/kg TCDD or vehicle control on day zero and then given either Con A or saline intravenously on day four. Mice treated with TCDD did not develop liver injury; however, TCDD pretreatment increased liver injurymore » resulting from moderate doses of Con A (4–10 mg/kg). TCDD-pretreated mice had altered plasma concentrations of inflammatory cytokines, including interferon gamma (IFNγ), and TCDD/Con A-induced hepatotoxicity was attenuated in IFNγ knockout mice. At various times after treatment, intrahepatic immune cells were isolated, and expression of cell activation markers as well as cytolytic proteins was determined. TCDD pretreatment increased the proportion of activated natural killer T (NKT) cells and the percent of cells expressing Fas ligand (FasL) after Con A administration. In addition FasL knockout mice and mice treated with CD18 antiserum were both protected from TCDD/Con A-induced hepatotoxicity, suggesting a requirement for direct cell–cell interaction between effector immune cells and parenchymal cell targets in the development of liver injury from TCDD/Con A treatment. In summary, exposure to TCDD increased NKT cell activation and exacerbated immune-mediated liver injury induced by Con A through a mechanism involving IFNγ and FasL expression. -- Highlights: ► TCDD pretreatment sensitizes mice to Con A-induced hepatotoxicity. ► TCDD pretreatment increased concentration of IFNγ in plasma after Con A. ► Con A-induced activation of NKT cells was increased by TCDD pretreatment. �

Dioxin-induced up-regulation of the active form of vitamin D is the main cause for its inhibitory action on osteoblast activities, leading to developmental bone toxicity

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

Nishimura, Noriko; Nishimura, Hisao; Ito, Tomohiro

2009-05-01

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) is known to cause bone toxicity, particularly during animal development, although its action mechanism to cause this toxicity has yet to be elucidated. Mouse pups were exposed to TCDD via dam's milk that were administered orally with 15 {mu}g TCDD/kg b.w. on postnatal day 1. Here we report that TCDD causes up-regulation of vitamin D 1{alpha}-hydroxylase in kidney, resulting in a 2-fold increase in the active form of vitamin D, 1,25-dihydroxyvitamin D{sub 3}, in serum. This action of TCDD is not caused by changes in parathyroid hormone, a decrease in vitamin D degrading enzyme, vitamin D 24-hydroxylase,more » or alterations in serum Ca{sup 2+} concentration. Vitamin D is known to affect bone mineralization. Our data clearly show that TCDD-exposed mice exhibit a marked decrease in osteocalcin and collagen type 1 as well as alkaline phosphatase gene expression in tibia by postnatal day 21, which is accompanied with a mineralization defect in the tibia, lowered activity of osteoblastic bone formation, and an increase in fibroblastic growth factor-23, a sign of increased vitamin D effect. Despite these significant effects of TCDD on osteoblast activities, none of the markers of osteoclast activities was found to be affected. Histomorphometry confirmed that osteoblastic activity, but not bone resorption activity, was altered by TCDD. A prominent lesion commonly observed in these TCDD-treated mice was impaired bone mineralization that is characterized by an increased volume and thickness of osteoids lining both the endosteum of the cortical bone and trabeculae. Together, these data suggest that the impaired mineralization resulting from reduction of the osteoblastic activity, which is caused by TCDD-induced up-regulation of vitamin D, is responsible for its bone developmental toxicity.« less

Solvent-induced dimensional changes in EDTA-demineralized dentin matrix.

PubMed

Pashley, D H; Agee, K A; Nakajima, M; Tay, F R; Carvalho, R M; Terada, R S; Harmon, F J; Lee, W K; Rueggeberg, F A

2001-08-01

The purpose of this study was to test the null hypothesis that the re-expansion of dried matrix and the shrinkage of moist, demineralized dentin is not influenced by polar solvents. Dentin disks were prepared from midcoronal dentin of extracted human third molars. After complete demineralization in 0.5M of EDTA (pH 7), the specimens were placed in the well of a device that measures changes in matrix height in real time. Dry, collapsed matrices were created by blowing dry N(2) on the specimens until they shrank to a stable plateau. Polar solvents [water, methanol, ethanol, n-propanol, n-butanol, formamide, ethylene glycol, hydroxyethyl methacrylate (HEMA), or mixtures of water-HEMA] as model primers then were added and the degree of re-expansion measured. These same solvents also were applied to moist, expanded matrices and the solvent-induced shrinkages measured. Regression analysis was used to test the correlations between matrix height and Hansen's dispersive, polar, hydrogen bonding, and total solubility parameters (delta(d), delta(p), delta(h), delta(t)). The results indicate that water-free polar solvents of low hydrogen bonding (H-bond) ability (e.g., neat HEMA) do not re-expand dried matrices and that they shrink moist matrices. When HEMA was mixed with progressively higher water concentrations, the model water-HEMA primers expanded the dried matrix in proportion to their water concentrations and they produced less shrinkage of moist matrices. Solvents with higher H-bonding capacities (methanol, ethanol, ethylene glycol, formamide, and water) re-expanded the dried matrix in proportion to their solubility parameters for H-bonding (delta(h)). They also induced small transient shrinkages of moist matrices, which slowly re-expanded. The results require rejection of the null hypothesis. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 56: 273-281, 2001

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

Gao, Zhan

Cleft palate is caused by the failure of palatal midline epithelial cells to disintegrate, which is necessary for palatal mesenchymal confluence. Although 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure is linked to cleft palate at a high rate, the mechanism remains to be elucidated. The present study was designed to determine the effects of TCDD on the fate of epithelial cell isolated from human fetal palatal shelves (hFPECs). We demonstrate that TCDD increased cell proliferation and promoted the progression of cells from G1 to S phase as well as increased the number of cells entering the G2/M phase. We found that TCDD has nomore » measurable effect on apoptosis of hFPECs. The protein level assays revealed that TCDD increased cyclin-dependent kinases 4 (cdk4), cyclin D1, cyclin E and p21 (Waf1/Cip1) but not cdk2, bcl-2, cyclin B1 and cyclin A. Furthermore, TCDD activated PI3K/AKT signaling, and the PI3K inhibitor, LY294002, partially abrogated TCDD-induced cell proliferation and gene modulations. TCDD treatment increased CYP1A1 mRNA and protein levels, which indicated the activation of AhR signaling. Knockdown of the AhR with siRNA suppressed TCDD-induced cell proliferation and PI3K/AKT signaling activation. Taken together, these data demonstrated that TCDD is able to promote growth of hFPECs through AhR-dependent activation of the PI3K/AKT pathway, which may account for the underlying mechanism by which TCDD causes a failure of palatal fusion. - Highlights: • TCDD promoted the cell growth with a character of significant accumulation of cells in G2/M. • TCDD treatment induced a various profile of cell cycle regulatory proteins. • PI3K/AKT pathway was involved in TCDD-induced cell proliferation and gene modifications. • AhR knockdown blocked TCDD-induced cell proliferation and PI3K/Akt signaling activation.« less

Role of cells in freezing-induced cell-fluid-matrix interactions within engineered tissues.

PubMed

Seawright, Angela; Ozcelikkale, Altug; Dutton, Craig; Han, Bumsoo

2013-09-01

During cryopreservation, ice forms in the extracellular space resulting in freezing-induced deformation of the tissue, which can be detrimental to the extracellular matrix (ECM) microstructure. Meanwhile, cells dehydrate through an osmotically driven process as the intracellular water is transported to the extracellular space, increasing the volume of fluid for freezing. Therefore, this study examines the effects of cellular presence on tissue deformation and investigates the significance of intracellular water transport and cell-ECM interactions in freezing-induced cell-fluid-matrix interactions. Freezing-induced deformation characteristics were examined through cell image deformetry (CID) measurements of collagenous engineered tissues embedded with different concentrations of MCF7 breast cancer cells versus microspheres as their osmotically inactive counterparts. Additionally, the development of a biophysical model relates the freezing-induced expansion of the tissue due to the cellular water transport and the extracellular freezing thermodynamics for further verification. The magnitude of the freezing-induced dilatation was found to be not affected by the cellular water transport for the cell concentrations considered; however, the deformation patterns for different cell concentrations were different suggesting that cell-matrix interactions may have an effect. It was, therefore, determined that intracellular water transport during freezing was insignificant at the current experimental cell concentrations; however, it may be significant at concentrations similar to native tissue. Finally, the cell-matrix interactions provided mechanical support on the ECM to minimize the expansion regions in the tissues during freezing.

Defining suitable reference genes for RT-qPCR analysis on human sertoli cells after 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure.

PubMed

Ribeiro, Mariana Antunes; dos Reis, Mariana Bisarro; de Moraes, Leonardo Nazário; Briton-Jones, Christine; Rainho, Cláudia Aparecida; Scarano, Wellerson Rodrigo

2014-11-01

Quantitative real-time RT-PCR (qPCR) has proven to be a valuable molecular technique to quantify gene expression. There are few studies in the literature that describe suitable reference genes to normalize gene expression data. Studies of transcriptionally disruptive toxins, like tetrachlorodibenzo-p-dioxin (TCDD), require careful consideration of reference genes. The present study was designed to validate potential reference genes in human Sertoli cells after exposure to TCDD. 32 candidate reference genes were analyzed to determine their applicability. geNorm and NormFinder softwares were used to obtain an estimation of the expression stability of the 32 genes and to identify the most suitable genes for qPCR data normalization.

TERATOGENICITY OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) IN MICE LACKING THE EXPRESSION OF EGF AND/OR TGFALPHA

EPA Science Inventory

Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure produces hydronephrosis and cleft palate in mice. These responses are correlated with disruption of expression of epidermal growth factor (EGF) receptor ligands, primarily EGF and transforming growth factor-alpha ...

Studies of matrix vesicle-induced mineralization in a gelatin gel

NASA Technical Reports Server (NTRS)

Boskey, A. L.; Boyan, B. D.; Doty, S. B.; Feliciano, A.; Greer, K.; Weiland, D.; Swain, L. D.; Schwartz, Z.

1992-01-01

Matrix vesicles isolated from fourth-passage cultures of chondrocytes were tested for their ability to induce hydroxyapatite formation in a gelatin gel in order to gain insight into the function of matrix vesicles in in situ mineralization. These matrix vesicles did not appear to be hydroxyapatite nucleators per se since the extent of mineral accumulation in the gel diffusion system was not altered by the presence of matrix vesicles alone, and in the vesicle containing gels, mineral crystals were formed whether associated with vesicles or not. In gels with these matrix vesicles and beta-glycerophosphate, despite the presence of alkaline phosphatase activity, there was no increase in mineral deposition. This suggested that in the gel system these culture-derived vesicles did not increase local phosphate concentrations. However, when known inhibitors of mineral crystal formation and growth (proteoglycan aggregates [4 mg/ml], or ATP [1 mM], or both proteoglycan and ATP) were included in the gel, more mineral was deposited in gels with the vesicles than in comparable gels without vesicles, indicating that enzymes within these vesicles were functioning to remove the inhibition. These data support the suggestion that one function of the extracellular matrix vesicles is to transport enzymes for matrix modification.

Effects of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected into the yolks of chicken (Gallus domesticus) eggs prior to incubation

USGS Publications Warehouse

Powell, D.C.; Aulerich, R.J.; Meadows, J.C.; Tillitt, D.E.; Giesy, J.P.; Stromborg, K.L.; Bursian, S.J.

1996-01-01

The yolks of White Leghorn chicken (Gallus domesticus) eggs were injected prior to incubation with either 3,3′,4,4′,5- pentachlorobiphenyl (PCB 126) at doses ranging from 0.1 to 12.8 μg/kg egg or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at doses ranging from 0.04 to 0.64 μg/kg egg. Chicks were subjected to necropsy within 24 h of hatching. The brain, bursa, heart, liver, and spleen were removed and weighed. Assessment of the rate of hatching indicated an LD50±S.E. of 2.3±0.19 μg/kg egg (7.1±0.58 nmol/kg egg) for PCB 126 and 0.15±0.012 μg/kg egg (0.47±0.037 nmol/kg egg) for TCDD. No significant differences in the incidence of developmental abnormalities (structural defects and edema) were observed in TCDD-exposed embryos, while PCB 126 caused significantly more developmental abnormalities at 3.2, 6.4, and 12.8 μg/kg egg than the vehicle control. PCB 126 caused lower hatchling weights and greater relative brain, heart, and liver weights when compared to the vehicle control group at a dose of 3.2 μg/kg egg which is greater than the LD50. TCDD at 0.08 μg/kg egg caused relative bursa weights to be less than those of the vehicle control. A toxic equivalency factor (TEF) of 0.07 was determined for PCB 126 in relation to TCDD based on overt lethality.

Developmental Exposure of Mice to TCDD Elicits a Similar Uterine Phenotype in Adult Animals as Observed in Women with Endometriosis

PubMed Central

Nayyar, Tultul; Bruner-Tran, Kaylon L.; Piestrzeniewicz-Ulanska, Dagmara; Osteen, Kevin G.

2007-01-01

Whether environmental toxicants impact an individual woman’s risk for developing endometriosis remains uncertain. Although the growth of endometrial glands and stroma at extra-uterine sites is associated with retrograde menstruation, our studies suggest that reduced responsiveness to progesterone may increase the invasive capacity of endometrial tissue in women with endometriosis. Interestingly, our recent studies using isolated human endometrial cells in short-term culture suggest that experimental exposure to the environmental contaminant 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) can alter the expression of progesterone receptor isotypes. Compared to adult exposure, toxicant exposure during development can exert a significantly greater biological impact, potentially affecting the incidence of endometriosis in adults. To address this possibility, we exposed mice to TCDD at critical developmental time points and subsequently examined uterine progesterone receptor expression and steroid responsive transforming growth factor-β2 expression in adult animals. We find that the uterine phenotype of toxicant-exposed mice is markedly similarly to the endometrial phenotype of women with endometriosis. PMID:17056225

PERSISTENT ABNORMALITIES IN THE RAT MAMMARY GLAND FOLLOWING GESTATIONAL AND LACTATIONAL EXPOSURE TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

EPA Science Inventory

SUMMARY

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure during gestation has revealed reproductive anomalies in rat offspring, including inconclusive reports of stunted mammary development in females (Brown et al., 1998, Lewis et al., 2001). The current studies wer...

2,3,7,8-Tetrachlorodibenzo-P-Dioxin (TCDD) Dose-Response Studies: Preliminary Literature Search Results and Request for Additional Studies

EPA Science Inventory

EPA invited the public to comment on the preliminary list of in vivo mammalian dose-response citations for 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD). This list was compiled as a first step in the development of EPA’s response to the National Academy of Sciences comments (NAS, 2...

Expression of extracellular matrix metalloproteinase inducer in odontogenic cysts.

PubMed

Ali, Mohammad Abdulhadi Abbas

2008-08-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) is known to induce matrix metalloproteinase (MMP) production. The expression of EMMPRIN in odontogenic cysts has not been previously studied. This study was done to determine the presence and the variability of EMMPRIN expression in various types of odontogenic cysts. An immunohistochemical study using a polyclonal anti-EMMPRIN antibody was done using 48 odontogenic cyst cases: 13 odontogenic keratocysts (OKCs), 18 dentigerous cysts (DCs), and 17 periapical cysts (PAs). Twelve cases of normal dental follicles (DFs) were also included in this study for comparison. EMMPRIN immunoreactivity was detected in all of the cysts and DFs studied. In odontogenic cysts, EMMPRIN immunoreactivity was generally higher in basal cells than in suprabasal cells. The overall EMMPRIN expression in the epithelial lining of the 3 different types of odontogenic cyst was significantly higher than in the DFs. Overall EMMPRIN expression was also found to be significantly higher in the epithelial lining of OKCs than in the other types of cysts. This study confirmed that EMMPRIN is present in odontogenic cysts and DFs. The higher EMMPRIN expression in OKCs suggests that it may be involved in the aggressive behavior of this type of cyst.

In utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure: Effects on fetal and adult cardiac gene expression and adult cardiac and renal morphology

USDA-ARS?s Scientific Manuscript database

The mouse heart is a target of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during fetal development, and microarray analysis demonstrates significant changes in expression of cardiac genes involved in extracellular matrix (ECM) remodeling. We tested the hypothesis that developmental TCDD exposure wo...

Compound- and sex-specific effects on programming of energy and immune homeostasis in adult C57BL/6JxFVB mice after perinatal TCDD and PCB 153.

PubMed

van Esterik, J C J; Verharen, H W; Hodemaekers, H M; Gremmer, E R; Nagarajah, B; Kamstra, J H; Dollé, M E T; Legler, J; van der Ven, L T M

2015-12-01

Early life exposure to endocrine disrupting compounds has been linked to chronic diseases later in life, like obesity and related metabolic disorders. We exposed C57BL/6JxFVB hybrid mice to the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the constitutive androstane receptor/pregnane X receptor agonist polychlorinated biphenyl 153 (PCB 153) in an experimental design relevant for human exposure. Exposure occurred during gestation and lactation via maternal feed to a wide dose range (TCDD: 10-10,000 pg/kg body weight/day; PCB 153: 0.09-1406 μg/kg body weight/d). Then exposure was ceased and offspring were followed up to 1 year of age. Metabolic parameters like body weight, fat pad weights, glucose tolerance, endocrine serum profile, and neurobehavioral and immunological parameters were determined. Body weight was transiently affected by both compounds throughout the follow-up. TCDD-exposed males showed decreased fat pad and spleen weights and an increase in IL-4 production of splenic immune cells. In contrast, females showed increased fat pad weights and production of IFNγ. PCB 153-exposed males showed an increase in glucose, whereas females showed an increase in glucagon, a decrease in pancreas weight, and an increase in thymus weight. In conclusion, early life exposure to TCDD appears to affect programming of energy and immune homeostasis in offspring, whereas the effects of perinatal PCB 153 were mainly on programming of glucose homeostasis. Both compounds act sex-specifically. Lowest derived BMDLs (lower bounds of the (two sided) 90%-confidence interval for the benchmark dose) for both compounds are not lower than current tolerable daily intakes.

EMERGING TECHNOLOGY REPORT: BENCH-SCALE TESTING OF PHOTOLYSIS, CHEMICAL OXIDATION AND BIODEGRADATION OF PCB CONTAMINATED SOILS AND PHOTOLYSIS OF TCDD CONTAMINATED SOILS

EPA Science Inventory

This report presents the results of bench-scale testing on degradation of 2,3,7,8-TCDD using W photolysis, and PCB degradation using UV photolysis, chemical oxidation and biological treatment. Bench-scale tests were conducted to investigate the feasibility of a two-phase detoxifi...

2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) DISRUPTS EARLY MORPHOGENETIC EVENTS THAT FORM THE LOWER REPRODUCTIVE TRACT IN FEMALE RAT FETUSES

EPA Science Inventory

In female rats, in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during critical periods of organogenesis causes a permanent thread of tissue across the vaginal opening, which consists of a core of mesenchyme surrounded by keratinized epithelia. The objective of t...

Aryl Hydrocarbon Receptor Protects Lungs from Cockroach Allergen-Induced Inflammation by Modulating Mesenchymal Stem Cells.

PubMed

Xu, Ting; Zhou, Yufeng; Qiu, Lipeng; Do, Danh C; Zhao, Yilin; Cui, Zhuang; Wang, Heng; Liu, Xiaopeng; Saradna, Arjun; Cao, Xu; Wan, Mei; Gao, Peisong

2015-12-15

Exposure to cockroach allergen leads to allergic sensitization and increased risk of developing asthma. Aryl hydrocarbon receptor (AhR), a receptor for many common environmental contaminants, can sense not only environmental pollutants but also microbial insults. Mesenchymal stem cells (MSCs) are multipotent progenitor cells with the capacity to modulate immune responses. In this study, we investigated whether AhR can sense cockroach allergens and modulate allergen-induced lung inflammation through MSCs. We found that cockroach allergen-treated AhR-deficient (AhR(-/-)) mice showed exacerbation of lung inflammation when compared with wild-type (WT) mice. In contrast, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an AhR agonist, significantly suppressed allergen-induced mouse lung inflammation. MSCs were significantly reduced in cockroach allergen-challenged AhR(-/-) mice as compared with WT mice, but increased in cockroach allergen-challenged WT mice when treated with TCDD. Moreover, MSCs express AhR, and AhR signaling can be activated by cockroach allergen with increased expression of its downstream genes cyp1a1 and cyp1b1. Furthermore, we tracked the migration of i.v.-injected GFP(+) MSCs and found that cockroach allergen-challenged AhR(-/-) mice displayed less migration of MSCs to the lungs compared with WT. The AhR-mediated MSC migration was further verified by an in vitro Transwell migration assay. Epithelial conditioned medium prepared from cockroach extract-challenged epithelial cells significantly induced MSC migration, which was further enhanced by TCDD. The administration of MSCs significantly attenuated cockroach allergen-induced inflammation, which was abolished by TGF-β1-neutralizing Ab. These results suggest that AhR plays an important role in protecting lungs from allergen-induced inflammation by modulating MSC recruitment and their immune-suppressive activity. Copyright © 2015 by The American Association of Immunologists, Inc.

Hydrogen sulfide inhibits high glucose-induced NADPH oxidase 4 expression and matrix increase by recruiting inducible nitric oxide synthase in kidney proximal tubular epithelial cells.

PubMed

Lee, Hak Joo; Lee, Doug Yoon; Mariappan, Meenalakshmi M; Feliers, Denis; Ghosh-Choudhury, Goutam; Abboud, Hanna E; Gorin, Yves; Kasinath, Balakuntalam S

2017-04-07

High-glucose increases NADPH oxidase 4 (NOX4) expression, reactive oxygen species generation, and matrix protein synthesis by inhibiting AMP-activated protein kinase (AMPK) in renal cells. Because hydrogen sulfide (H 2 S) inhibits high glucose-induced matrix protein increase by activating AMPK in renal cells, we examined whether H 2 S inhibits high glucose-induced expression of NOX4 and matrix protein and whether H 2 S and NO pathways are integrated. High glucose increased NOX4 expression and activity at 24 h in renal proximal tubular epithelial cells, which was inhibited by sodium hydrosulfide (NaHS), a source of H 2 S. High glucose decreased AMPK phosphorylation and activity, which was restored by NaHS. Compound C, an AMPK inhibitor, prevented NaHS inhibition of high glucose-induced NOX4 expression. NaHS inhibition of high glucose-induced NOX4 expression was abrogated by N (ω)-nitro-l-arginine methyl ester, an inhibitor of NOS. NaHS unexpectedly augmented the expression of inducible NOS (iNOS) but not endothelial NOS. iNOS siRNA and 1400W, a selective iNOS inhibitor, abolished the ameliorative effects of NaHS on high glucose-induced NOX4 expression, reactive oxygen species generation, and, matrix laminin expression. Thus, H 2 S recruits iNOS to generate NO to inhibit high glucose-induced NOX4 expression, oxidative stress, and matrix protein accumulation in renal epithelial cells; the two gasotransmitters H 2 S and NO and their interaction may serve as therapeutic targets in diabetic kidney disease. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Developmental toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in artificially fertilized crucian carp (Carassius auratus) embryo.

PubMed

Park, Yong Joo; Lee, Min Jee; Kim, Ha Ryong; Chung, Kyu Hyuck; Oh, Seung Min

2014-09-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent bioaccumulative environmental contaminant that is an endocrine disruptor. Embryos of various fish species are responsive to TCDD and have been used as an alternative method to the acute toxicity test with juvenile and adult fish. The TCDD test has similar endpoints of developmental toxicity. However, their sensitivity and signs of TCDD-induced toxicity are different depending on fish species and its habit. Crucian carp (Carassius auratus) - the sentinel species for persistent organic pollutants and a common foodfish in China, Japan, and Korea - was used to identify the developmental toxicity of TCDD. We obtained the fertilized eggs from the artificial fertilization of crucian carp (97.45% success rate). Embryos at 3h post fertilization (hpf) were exposed to no vehicle, vehicle (dimethylsulfoxide, 0.1% v/v) or TCDD (0.128, 0.32, 0.8, 2 and 5 μg/L) for 1h and then fresh water was changed and aerated. Embryonic development and toxicity were monitored until 150 hpf. TCDD-exposed group showed no effects on embryo mortality and hatching rate from 6 to 126 hpf. On the other hand, the post-hatching mortality rate in TCDD-exposed group was increased in a dose-dependent manner, especially at high doses (0.8, 2 and 5 μg/L). The LD50 for larval mortality was calculated to 0.24 ng TCDD/g embryo. Pericardial edema was continuously observed in larvae of TCDD-exposed groups from hatching complete time (78 hpf), followed by the onset of yolk sac edema. Hemorrhage and edema showed a significant increase depending on exposure concentration and time. Expression of TCDD-related CYP1A genes was evaluated quantitatively. Embryo and larvae in TCDD-exposed groups displayed a significant increase of CYP1A gene expression. Overall, we defined TCDD-induced toxicity in artificially fertilized crucian carp embryo and these results suggest that crucian carp can be applied as an early life stage model of TCDD-induced toxicity. Copyright

EXPRESSION OF EGFR AND ITS LIGANDS IN RESPONSE TO TCDD OR RETINOIC ACID IN EGF AND TGFALPHA KO FETAL MOUSE PALATE

EPA Science Inventory

EXPRESSION OF EGFR AND ITS LIGANDS IN RESPONSE TO TCDD OR RETINOIC ACID IN EGF AND TGF" KO FETAL MOUSE PALATE. Abbott, Barbara D.1; Boyd, Hadiya2; Wood, Carmen1; Held, Gary1. 1.EPA, ORD, NHEERL, RTD, US EPA, Research Triangle Park, NC, USA. 2MARC Program, NCCU, Durham, NC, USA. <...

Critical review of the developmental toxicity and teratogenicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin: Recent advances toward understanding the mechanism

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

Couture, L.A.; Abbott, B.D.; Birnbaum, L.S.

1990-01-01

A specific teratogenic response is elicited in the mouse as a result of exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin). The characteristic spectrum of structural malformations induced in mice following exposure to TCDD and structurally-related congeners is highly reproducible and includes both hydronephrosis and cleft palate. In addition, prenatal exposure to TCDD has been shown to induce thymic hypoplasia. The three abnormalities occur at doses well below those producing maternal or embryo/fetal toxicity, and are among the most sensitive indicators of dioxin toxicity. In all other laboratory species tested, TCDD causes maternal and embryo/fetal toxicity, but does not induce a significant increasemore » in the incidence of structural abnormalities even at toxic dose levels. Developmental toxicity occurs in a similar dose range across species, however, mice are particularly susceptible to development of TCDD-induced terata. Recent experiments using an organ culture were an attempt to address the issue of species and organ differences in sensitivity to TCDD. Human palatal shelves were examined in this in vitro system, and were found to approximate the rat in terms of sensitivity for induction of cleft palate.« less

Functional and phenotypic effects of AhR activation in inflammatory dendritic cells

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

Bankoti, Jaishree; Center for Environmental Health Sciences, University of Montana, Missoula, MT; Rase, Ben

2010-07-15

Aryl hydrocarbon receptor (AhR) activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immune suppression. Dendritic cells (DCs) are key antigen presenting cells governing T cell activation and differentiation. However, the consequences of AhR activation in DCs are not fully defined. We hypothesized that AhR activation alters DC differentiation and generates dysfunctional DCs. To test this hypothesis, inflammatory bone marrow-derived DCs (BMDCs) from C57Bl/6 mice were generated in the presence of vehicle or TCDD. TCDD decreased CD11c expression but increased MHC class II, CD86 and CD25 expression on the BMDCs. The effects of TCDD were strictly AhR-dependent but not exclusively DRE-mediated. Similar effects weremore » observed with two natural AhR ligands, 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid (ITE). TCDD increased LPS- and CpG-induced IL-6 and TNF-{alpha} production by BMDCs but decreased their NO production. TCDD decreased CpG-induced IL-12p70 production by BMDCs but did not affect their secretion of IL-10. TCDD downregulated LPS- and CpG-induced NF-kB p65 levels and induced a trend towards upregulation of RelB levels in the BMDCs. AhR activation by TCDD modulated BMDC uptake of both soluble and particulate antigens. Induction of indoleamine-2,3-dioxygenase (IDO) and TGF-{beta}3 has been implicated in the generation of regulatory T cells following AhR activation. TCDD increased IDO1, IDO2 and TGF-{beta}3 mRNA levels in BMDCs as compared to vehicle. Despite the induction of regulatory mediators, TCDD-treated BMDCs failed to suppress antigen-specific T cell activation. Thus, AhR activation can directly alter the differentiation and innate functions of inflammatory DCs without affecting their ability to successfully interact with T cells.« less

Hot flue-gas spiking and recovery study for tetrachlorodibenzodioxins (TCDD) using Modified Method 5 and SASS (Source Assessment Sampling System) sampling with a simulated incinerator. Final report, May 1981-February 1982

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

Cooke, M.; DeRoos, F.; Rising, B.

1984-10-01

The report gives results of an evaluation of the sampling and analysis of ultratrace levels of dibenzodioxins using EPA's recommended source sampling procedures (Modified Method 5 (MM5) train and the Source Assessment Sampling System--SASS). A gas-fired combustion system was used to simulate incineration flue gas, and a precision liquid injection system was designed for the program. The precision liquid injector was used to administer dilute solutions of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD) directly into a hot--260C (500F)--flue gas stream. Injections occurred continuously during the sampling episode so that very low gas-phase concentrations of 1,2,3,4-TCDD were continuously mixed with the flue gases. Recoveries weremore » measured for eight burn experiments. For all but one, the recoveries could be considered quantitative, demonstrating efficient collection by the EPA sampling systems. In one study, the components and connecting lines from a sampling device were analyzed separately to show where the 1,2,3,4-TCDD deposited in the train.« less

Regulation of Extracellular Matrix Remodeling Proteins by Osteoblasts in Titanium Nanoparticle-Induced Aseptic Loosening Model.

PubMed

Xie, Jing; Hou, Yanhua; Fu, Na; Cai, Xiaoxiao; Li, Guo; Peng, Qiang; Lin, Yunfeng

2015-10-01

Titanium (Ti)-wear particles, formed at the bone-implant interface, are responsible for aseptic loosening, which is a main cause of total joint replacement failure. There have been many studies on Ti particle-induced function changes in mono-cultured osteoblasts and synovial cells. However, little is known on extracellular matrix remodeling displayed by osteoblasts when in coexistence with Synovial cells. To further mimic the bone-implant interface environment, we firstly established a nanoscaled-Ti particle-induced aseptic loosening system by co-culturing osteoblasts and Synovial cells. We then explored the impact of the Synovial cells on Ti particle-engulfed osteoblasts in the mimicked flamed niche. The matrix metalloproteinases and lysyl oxidases expression levels, two protein families which are critical in osseointegration, were examined under induction by tumor necrosis factor-alpha. It was found that the co-culture between the osteoblasts and Synovial cells markedly increased the migration and proliferation of the osteoblasts, even in the Ti-particle engulfed osteoblasts. Importantly, the Ti-particle engulfed osteoblasts, induced by TNF-alpha after the co-culture, enhanced the release of the matrix metalloproteinases and reduced the expressions of lysyl oxidases. The regulation of extracellular matrix remodeling at the protein level was further assessed by investigations on gene expression of the matrix metalloproteinases and lysyl oxidases, which also suggested that the regulation started at the genetic level. Our research work has therefore revealed the critical role of multi cell-type interactions in the extracellular matrix remodeling within the peri-prosthetic tissues, which provides new insights on aseptic loosening and brings new clues about incomplete osseointegration between the implantation materials and their surrounding bones.

Biofilm matrix exoproteins induce a protective immune response against Staphylococcus aureus biofilm infection.

PubMed

Gil, Carmen; Solano, Cristina; Burgui, Saioa; Latasa, Cristina; García, Begoña; Toledo-Arana, Alejandro; Lasa, Iñigo; Valle, Jaione

2014-03-01

The Staphylococcus aureus biofilm mode of growth is associated with several chronic infections that are very difficult to treat due to the recalcitrant nature of biofilms to clearance by antimicrobials. Accordingly, there is an increasing interest in preventing the formation of S. aureus biofilms and developing efficient antibiofilm vaccines. Given the fact that during a biofilm-associated infection, the first primary interface between the host and the bacteria is the self-produced extracellular matrix, in this study we analyzed the potential of extracellular proteins found in the biofilm matrix to induce a protective immune response against S. aureus infections. By using proteomic approaches, we characterized the exoproteomes of exopolysaccharide-based and protein-based biofilm matrices produced by two clinical S. aureus strains. Remarkably, results showed that independently of the nature of the biofilm matrix, a common core of secreted proteins is contained in both types of exoproteomes. Intradermal administration of an exoproteome extract of an exopolysaccharide-dependent biofilm induced a humoral immune response and elicited the production of interleukin 10 (IL-10) and IL-17 in mice. Antibodies against such an extract promoted opsonophagocytosis and killing of S. aureus. Immunization with the biofilm matrix exoproteome significantly reduced the number of bacterial cells inside a biofilm and on the surrounding tissue, using an in vivo model of mesh-associated biofilm infection. Furthermore, immunized mice also showed limited organ colonization by bacteria released from the matrix at the dispersive stage of the biofilm cycle. Altogether, these data illustrate the potential of biofilm matrix exoproteins as a promising candidate multivalent vaccine against S. aureus biofilm-associated infections.

Polyphosphate induces matrix metalloproteinase-3-mediated proliferation of odontoblast-like cells derived from induced pluripotent stem cells

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

Ozeki, Nobuaki; Hase, Naoko; Yamaguchi, Hideyuki

2015-05-01

Inorganic polyphosphate [Poly(P)] may represent a physiological source of phosphate and has the ability to induce bone differentiation in osteoblasts. We previously reported that cytokine-induced matrix metalloproteinase (MMP)-3 accelerates the proliferation of purified odontoblast-like cells. In this study, MMP-3 small interfering RNA (siRNA) was transfected into odontoblast-like cells derived from induced pluripotent stem cells to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation and differentiation into odontoblast-like cells. Treatment with Poly(P) led to an increase in both cell proliferation and additional odontoblastic differentiation. Poly(P)-treated cells showed a small but significant increase in dentin sialophosphoproteinmore » (DSPP) and dentin matrix protein-1 (DMP-1) mRNA expression, which are markers of mature odontoblasts. The cells also acquired additional odontoblast-specific properties including adoption of an odontoblastic phenotype typified by high alkaline phosphatase (ALP) activity and a calcification capacity. In addition, Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity. MMP-3 siRNA-mediated disruption of the expression of these effectors potently suppressed the expression of odontoblastic biomarkers ALP, DSPP, and DMP-1, and blocked calcification. Interestingly, upon siRNA-mediated silencing of MMP-3, we noted a potent and significant decrease in cell proliferation. Using specific siRNAs, we revealed that a unique signaling cascade, Poly(P)→MMP-3→DSPP and/or DMP-1, was intimately involved in the proliferation of odontoblast-like cells. - Highlights: • Polyphosphate increases proliferation of iPS cell-derived odontoblast-like cells. • Polyphosphate-induced MMP-3 results in an increase of cell proliferation. • Induced cell proliferation involves MMP-3, DSPP, and/or DMP-1 sequentially. • Induced MMP-3 also results in an increase of

Tumorigenic Potential of Extracellular Matrix Metalloproteinase Inducer

PubMed Central

Zucker, Stanley; Hymowitz, Michelle; Rollo, Ellen E.; Mann, Richard; Conner, Cathleen E.; Cao, Jian; Foda, Hussein D.; Tompkins, David C.; Toole, Bryan P.

2001-01-01

Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycoprotein present on the cancer cell plasma membrane, enhances fibroblast synthesis of matrix metalloproteinases (MMPs). The demonstration that peritumoral fibroblasts synthesize most of the MMPs in human tumors rather than the cancer cells themselves has ignited interest in the role of EMMPRIN in tumor dissemination. In this report we have demonstrated a role for EMMPRIN in cancer progression. Human MDA-MB-436 breast cancer cells, which are tumorigenic but slow growing in vivo, were transfected with EMMPRIN cDNA and injected orthotopically into mammary tissue of female NCr nu/nu mice. Green fluorescent protein was used to visualize metastases. In three experiments, breast cancer cell clones transfected with EMMPRIN cDNA were considerably more tumorigenic and invasive than plasmid-transfected cancer cells. Increased gelatinase A and gelatinase B expression (demonstrated by in situ hybridization and gelatin substrate zymography) was demonstrated in EMMPRIN-enhanced tumors. In contrast to de novo breast cancers in humans, human tumors transplanted into mice elicited minimal stromal or inflammatory cell reactions. Based on these experimental studies and our previous demonstration that EMMPRIN is prominently displayed in human cancer tissue, we propose that EMMPRIN plays an important role in cancer progression by increasing synthesis of MMPs. PMID:11395366

PERSISTENT SUPPRESSION OF CONTACT HYPERSENSITIVITY, AND ALTERED T-CELL PARAMETERS IN F344 RATS EXPOSED PERINATALLY TO 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

EPA Science Inventory

Abstract
The outcome of perinatal low-level TCDD exposure on the T cell-mediated contact hypersensitivity response (CHS) in adult F344 rats was investigated. Suppression of the 2,4- dinitrofluorobenzene (DNFB)-specific contact hypersensitivity reponse occurred in mature off...

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

Kovalova, Natalia, E-mail: kovalova@msu.edu

Previous studies have demonstrated that most of the intraspecies variation in sensitivity to the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), including suppression of antibody responses, in murine models is due to single nucleotide polymorphisms (SNPs) within the aryl hydrocarbon receptor (AhR) gene. The underlying reason for variation in sensitivity to TCDD-induced suppression of IgM responses among humans is not well understood, but is thought, in part, to be a result of different polymorphic forms of the AhR expressed by different individuals. In this study, the functional properties of six (P517S, R554K, V570I, V570I + P517S, R554K + V570I and P517S +more » R554K + V570I) human AhR variants were examined in the human B cell line, SKW 6.4. TCDD-induced Cyp1B1 and Cyp1A2 mRNA expression levels and Cyp1B1-regulated reporter gene activity, used for comparative purposes, were markedly lower in SKW cells containing the R554K SNP than in SKW-AHR{sup +} (control AhR) cells. Furthermore, all AhR variants were able to mediate TCDD-induced suppression of the IgM response; however, a combined P517S + R554K + V570I variant partially reduced sensitivity to TCDD-mediated suppression of IgM secretion. Collectively, our findings show that the R554K human AhR SNP alone altered sensitivity of human B cells to TCDD-mediated induction of Cyp1B1 and Cyp1A2. By contrast, attenuation of TCDD-induced IgM suppression required a combination of all three SNPs P517S, R554K, and V570I. - Highlights: • Mouse, rat and SKW-AHR{sup +} B cells have a similar window of sensitivity to TCDD. • R554K AhR SNP alters B cell sensitivity to TCDD-mediated Cyp1B1 and Cyp1A2 induction. • Combination of P517S, R554K, and V570I SNPs attenuates TCDD-induced IgM suppression.« less

Multiscale alterations in bone matrix quality increased fragility in steroid induced osteoporosis

PubMed Central

Karunaratne, A.; Xi, L.; Bentley, L.; Sykes, D.; Boyde, A.; Esapa, C.T.; Terrill, N.J.; Brown, S.D.M.; Cox, R.D.; Thakker, R.V.; Gupta, H.S.

2016-01-01

A serious adverse clinical effect of glucocorticoid steroid treatment is secondary osteoporosis, enhancing fracture risk in bone. This rapid increase in bone fracture risk is largely independent of bone loss (quantity), and must therefore arise from degradation of the quality of the bone matrix at the micro- and nanoscale. However, we lack an understanding of both the specific alterations in bone quality n steroid-induced osteoporosis as well as the mechanistic effects of these changes. Here we demonstrate alterations in the nanostructural parameters of the mineralized fibrillar collagen matrix, which affect bone quality, and develop a model linking these to increased fracture risk in glucocorticoid induced osteoporosis. Using a mouse model with an N-ethyl-N-nitrosourea (ENU)-induced corticotrophin releasing hormone promoter mutation (Crh− 120/+) that developed hypercorticosteronaemia and osteoporosis, we utilized in situ mechanical testing with small angle X-ray diffraction, synchrotron micro-computed tomography and quantitative backscattered electron imaging to link altered nano- and microscale deformation mechanisms in the bone matrix to abnormal macroscopic mechanics. We measure the deformation of the mineralized collagen fibrils, and the nano-mechanical parameters including effective fibril modulus and fibril to tissue strain ratio. A significant reduction (51%) of fibril modulus was found in Crh− 120/+ mice. We also find a much larger fibril strain/tissue strain ratio in Crh− 120/+ mice (~ 1.5) compared to the wild-type mice (~ 0.5), indicative of a lowered mechanical competence at the nanoscale. Synchrotron microCT show a disruption of intracortical architecture, possibly linked to osteocytic osteolysis. These findings provide a clear quantitative demonstration of how bone quality changes increase macroscopic fragility in secondary osteoporosis. PMID:26657825

Thermomechanical analysis of freezing-induced cell-fluid-matrix interactions in engineered tissues

PubMed Central

Han, Bumsoo; Teo, Ka Yaw; Ghosh, Soham; Dutton, J. Craig; Grinnell, Frederick

2012-01-01

Successful cryopreservation of functional engineered tissues (ETs) is significant to tissue engineering and regenerative medicine, but it is extremely challenging to develop a successful protocol because the effects of cryopreservation parameters on the post-thaw functionality of ETs are not well understood. Particularly, the effects on the microstructure of their extracellular matrix (ECM) have not been well studied, which determines many functional properties of the ETs. In this study, we investigated the effects of two key cryopreservation parameters – i) freezing temperature and corresponding cooling rate; and ii) the concentration of cryoprotective agent (CPA) on the ECM microstructure as well as the cellular viability. Using dermal equivalent as a model ET and DMSO as a model CPA, freezing-induced spatiotemporal deformation and post-thaw ECM microstructure of ETs was characterized while varying the freezing temperature and DMSO concentrations. The spatial distribution of cellular viability and the cellular actin cytoskeleton was also examined. The results showed that the tissue dilatation increased significantly with reduced freezing temperature (i.e., rapid freezing). A maximum limit of tissue deformation was observed for preservation of ECM microstructure, cell viability and cell-matrix adhesion. The dilatation decreased with the use of DMSO, and a freezing temperature dependent threshold concentration of DMSO was observed. The threshold DMSO concentration increased with lowering freezing temperature. In addition, an analysis was performed to delineate thermodynamic and mechanical components of freezing-induced tissue deformation. The results are discussed to establish a mechanistic understanding of freezing-induced cell-fluid-matrix interaction and phase change behavior within ETs in order to improve cryopreservation of ETs. PMID:23246556

EGF AND TGF ALPHA EXPRESSION INFLUENCE THE DEVELOPMENTAL TOXICITY OF TCDD: DOSE RESPONSE AND AHR PHENOTYPE IN EGF, TGF ALPHA AND EGF+TGF ALPHA KNOCKOUT MICE

EPA Science Inventory

Abstract
The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate (CP) and hydronephrosis (HN) in mice. The etiology of these defects involves hyperproliferation of epithelial cells of the secondary palatal shelf and ureter, respectively. ...

Transcriptional profiling of rat white adipose tissue response to 2,3,7,8-tetrachlorodibenzo-ρ-dioxin

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

Houlahan, Kathleen E.; Prokopec, Stephenie D.; Sun, Ren X.

Polychlorinated dibenzodioxins are environmental contaminants commonly produced as a by-product of industrial processes. The most potent of these, 2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD), is highly lipophilic, leading to bioaccumulation. White adipose tissue (WAT) is a major site for energy storage, and is one of the organs in which TCDD accumulates. In laboratory animals, exposure to TCDD causes numerous metabolic abnormalities, including a wasting syndrome. We therefore investigated the molecular effects of TCDD exposure on WAT by profiling the transcriptomic response of WAT to 100 μg/kg of TCDD at 1 or 4 days in TCDD-sensitive Long-Evans (Turku/AB; L-E) rats. A comparative analysis was conductedmore » simultaneously in identically treated TCDD-resistant Han/Wistar (Kuopio; H/W) rats one day after exposure to the same dose. We sought to identify transcriptomic changes coinciding with the onset of toxicity, while gaining additional insight into later responses. More transcriptional responses to TCDD were observed at 4 days than at 1 day post-exposure, suggesting WAT shows mostly secondary responses. Two classic AHR-regulated genes, Cyp1a1 and Nqo1, were significantly induced by TCDD in both strains, while several genes involved in the immune response, including Ms4a7 and F13a1 were altered in L-E rats alone. We compared genes affected by TCDD in rat WAT and human adipose cells, and observed little overlap. Interestingly, very few genes involved in lipid metabolism exhibited altered expression levels despite the pronounced lipid mobilization from peripheral fat pads by TCDD in L-E rats. Of these genes, the lipolysis-associated Lpin1 was induced slightly over 2-fold in L-E rat WAT on day 4. - Highlights: • Exposure to TCDD causes wasting syndrome in L-E rats but not in H/W rats. • We examined the transcriptome of TCDD-treated L-E and H/W rat white adipose tissue. • L-E WAT demonstrated altered abundance of several genes involved in immune response. �

Role of zebrafish cytochrome P450 CYP1C genes in the reduced mesencephalic vein blood flow caused by activation of AHR2

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

Kubota, Akira, E-mail: akubota@whoi.edu; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; Stegeman, John J.

2011-06-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). We previously reported a sensitive and useful endpoint of TCDD developmental toxicity in zebrafish, namely a decrease in blood flow in the dorsal midbrain, but downstream genes involved in the effect are not known. The present study addressed the role of zebrafish cytochrome P450 1C (CYP1C) genes in association with a decrease in mesencephalic vein (MsV) blood flow. The CYP1C subfamily was recently discovered in fish and includes the paralogues CYP1C1 and CYP1C2, both of which are induced viamore » AHR2 in zebrafish embryos. We used morpholino antisense oligonucleotides (MO or morpholino) to block initiation of translation of the target genes. TCDD-induced mRNA expression of CYP1Cs and a decrease in MsV blood flow were both blocked by gene knockdown of AHR2. Gene knockdown of CYP1C1 by two different morpholinos and CYP1C2 by two different morpholinos, but not by their 5 nucleotide-mismatch controls, was effective in blocking reduced MsV blood flow caused by TCDD. The same CYP1C-MOs prevented reduction of blood flow in the MsV caused by {beta}-naphthoflavone (BNF), representing another class of AHR agonists. Whole-mount in situ hybridization revealed that mRNA expression of CYP1C1 and CYP1C2 was induced by TCDD most strongly in branchiogenic primordia and pectoral fin buds. In situ hybridization using head transverse sections showed that TCDD increased the expression of both CYP1Cs in endothelial cells of blood vessels, including the MsV. These results indicate a potential role of CYP1C1 and CYP1C2 in the local circulation failure induced by AHR2 activation in the dorsal midbrain of the zebrafish embryo. - Research Highlights: > We examine the roles of zebrafish CYP1C1 and CYP1C2 in TCDD developmental toxicity. > TCDD induces mRNA expression of both CYP1Cs in the mesencephalic vein. > Knockdown

Cytochrome P4501A1 is Required for Vascular Dysfunction and Hypertension Induced by 2,3,7,8-Tetrachlorodibenzo-p-dioxin

USDA-ARS?s Scientific Manuscript database

National Health and Nutrition Examination Survey data show an association between hypertension and exposure to dioxin-like halogenated aromatic hydrocarbons (HAH). Further, chronic exposure of mice to the prototypical HAH, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), induces reactive oxygen species (...

Internal damping due to dislocation movements induced by thermal expansion mismatch between matrix and particles in metal matrix composites. [Al/SiC

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

Girand, C.; Lormand, G.; Fougeres, R.

In metal matrix composites (MMCs), the mechanical 1 of the reinforcement-matrix interface is an important parameter because it governs the load transfer from matrix to particles, from which the mechanical properties of these materials are derived. Therefore, it would be useful to set out an experimental method able to characterize the interface and the adjacent matrix behaviors. Thus, a study has been undertaken by means of internal damping (I.D.) measurements, which are well known to be very sensitive for studying irreversible displacements at the atomic scale. More especially, this investigation is based on the fact that, during cooling of MMC's,more » stress concentrations originating from differences in coefficients of thermal expansion (C.T.E.) of matrix and particles should induce dislocation movements in the matrix surrounding the reinforcement; that is, local microplastic strains occur. Therefore, during I.D. measurements vs temperature these movements should contribute to MMCs I.D. in a process similar to those involved around first order phase transitions in solids. The aim of this paper is to present, in the case of Al/SiC particulate composites, new developments of this approach that has previously led to promising results in the case of Al-Si alloys.« less

Inhibition of leptin-induced vascular extracellular matrix remodelling by adiponectin.

PubMed

Zhang, Zhi; Wang, Fang; Wang, Bing-Jian; Chu, Guang; Cao, Qunan; Sun, Bao-Gui; Dai, Qiu-Yan

2014-10-01

Vascular extracellular matrix (ECM) remodelling, which is the result of disruption in the balance of ECM synthesis and degradation, induces vessel fibrosis and thereby leads to hypertension. Leptin is known to promote tissue fibrosis, while adiponectin has recently been demonstrated to be anti-fibrogenic in tissue fibrosis. In this study, we aimed to evaluate the leptin-antagonist function of adiponectin and to further elucidate the mechanisms through which adiponectin dampens leptin signalling in vascular smooth muscle cells, thus preventing excess ECM production, in our already established 3D co-culture vessel models. Our 3D co-culture vessel model, which mimics true blood vessels, is composed of vascular endothelial cells, vascular smooth muscle cells and collagen type I. We validated the profibrogenic effects of leptin and analysed matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase 1 (TIMP1) and collagen types II/IV secretion in 3D vessel models. The protective/inhibitory effects of adiponectin were re-analysed by inhibiting adiponectin receptor 1 (AdipoR) and AdipoR2 expression in endothelial cells using RNAi technology. In the 3D vessel models, adiponectin blocked the leptin-stimulated secretion of collagen types II/IV and TIMP1 while significantly increasing MMP2/9 activity. In endothelial cells, adiponectin induced phosphorylation of AMPK, thereby suppressing leptin-mediated STAT3 phosphorylation through induction of SOCS3 in smooth muscle cells. Our findings indicate that adiponectin disrupted the leptin-induced vascular ECM remodelling via AdipoR1 and enhanced AMPK signalling in endothelial cells, which, in turn, promoted SOCS3 up-regulation in smooth muscle cells to repress leptin-stimulated phosphorylation of STAT3. © 2014 The authors.

Inhibition of leptin-induced vascular extracellular matrix remodelling by adiponectin

PubMed Central

Zhang, Zhi; Wang, Fang; Wang, Bing-jian; Chu, Guang; Cao, Qunan; Sun, Bao-Gui; Dai, Qiu-Yan

2014-01-01

Vascular extracellular matrix (ECM) remodelling, which is the result of disruption in the balance of ECM synthesis and degradation, induces vessel fibrosis and thereby leads to hypertension. Leptin is known to promote tissue fibrosis, while adiponectin has recently been demonstrated to be anti-fibrogenic in tissue fibrosis. In this study, we aimed to evaluate the leptin-antagonist function of adiponectin and to further elucidate the mechanisms through which adiponectin dampens leptin signalling in vascular smooth muscle cells, thus preventing excess ECM production, in our already established 3D co-culture vessel models. Our 3D co-culture vessel model, which mimics true blood vessels, is composed of vascular endothelial cells, vascular smooth muscle cells and collagen type I. We validated the profibrogenic effects of leptin and analysed matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase 1 (TIMP1) and collagen types II/IV secretion in 3D vessel models. The protective/inhibitory effects of adiponectin were re-analysed by inhibiting adiponectin receptor 1 (AdipoR) and AdipoR2 expression in endothelial cells using RNAi technology. In the 3D vessel models, adiponectin blocked the leptin-stimulated secretion of collagen types II/IV and TIMP1 while significantly increasing MMP2/9 activity. In endothelial cells, adiponectin induced phosphorylation of AMPK, thereby suppressing leptin-mediated STAT3 phosphorylation through induction of SOCS3 in smooth muscle cells. Our findings indicate that adiponectin disrupted the leptin-induced vascular ECM remodelling via AdipoR1 and enhanced AMPK signalling in endothelial cells, which, in turn, promoted SOCS3 up-regulation in smooth muscle cells to repress leptin-stimulated phosphorylation of STAT3. PMID:24982243

Highly purified hexachlorobenzene induces cytochrome P4501A in primary cultures of chicken embryo hepatocytes

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

Mundy, Lukas J.; Environment Canada, National Wildlife Research Centre, Ottawa, Ontario; Jones, Stephanie P.

Some uncertainty exists regarding the purity of hexachlorobenzene (HCB) used in past toxicity studies. It has been suggested that reported toxic and biochemical effects initially attributed to HCB exposure may have actually been elicited by contamination of HCB by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Herein, primary cultures of chicken embryo hepatocytes (CEH) were used to compare the potencies of two lots of reagent-grade hexachlorobenzene (HCB-old [HCB-O] and HCB-new [HCB-N]), highly purified HCB (HCB-P) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as inducers of ethoxyresorufin O-deethylase (EROD) activity, cytochrome P4501A4 (CYP1A4) messenger ribonucleic acid (mRNA) and CYP1A5 mRNA. The study also compared themore » EROD- and CYP1A4/5 mRNA-inducing potencies of HCB to the potencies of two mono-ortho substituted polychlorinated biphenyls (PCBs), 2,3,3',4,4'-pentachlorobiphenyl (PCB 105) and 2,3'4,4',5-pentachlorobiphenyl (PCB 118). HCB-O, HCB-N and HCB-P all induced EROD activity and up-regulated CYP1A4 and CYP1A5 mRNAs. Induction was not caused by contamination of HCB with PCDDs or PCDFs. Based upon a comparison of the EC{sub 50} and EC{sub threshold} values for EROD and CYP1A4/5 mRNA concentration-response curves, the potency of HCB relative to the potency of TCDD was 0.0001, and was similar to that of PCB 105 and PCB 118. The maximal EROD activity and CYP1A4/5 mRNA expression differed greatly between HCB and TCDD, and may contribute to an overestimation of the ReP value calculated for highly purified HCB.« less

Creep-induced residual stress strengthening in a Nicalon-fiber-reinforced BMAS-glass-ceramic-matrix composite

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

Widjaja, S.; Jakus, K.; Ritter, J.E.

The feasibility of inducing a compressive residual stress in the matrix of a Nicalon-fiber-reinforced BMAS-glass-ceramic-matrix composite through a creep-load transfer treatment was studied. Specimens were crept at 1100 C under constant tensile load to cause load transfer from the matrix to the fibers, then cooled under load. Upon removal of the load at room temperature, the matrix was put into compression by the elastic recovery of the fibers. This compressive residual stress in the matrix increased the room-temperature proportional limit stress of the composite. The increase in the proportional limit stress was found to be dependent upon the applied creepmore » stress, with an increase in creep stress resulting in an increase in the proportional limit stress. Acoustic emission results showed that the onset of significant matrix cracking correlated closely to the proportional limit stress. Changes in the state of residual stress in the matrix were supported by X-ray diffraction results. Fracture surfaces of all specimens exhibited fiber pullout behavior, indicating that the creep-load transfer process did not embrittle the fiber/matrix interface.« less

Loss of the Mono-ADP-ribosyltransferase, Tiparp, Increases Sensitivity to Dioxin-induced Steatohepatitis and Lethality*

PubMed Central

Ahmed, Shaimaa; Bott, Debbie; Gomez, Alvin; Tamblyn, Laura; Rasheed, Adil; Cho, Tiffany; MacPherson, Laura; Sugamori, Kim S.; Yang, Yang; Grant, Denis M.; Cummins, Carolyn L.; Matthews, Jason

2015-01-01

The aryl hydrocarbon receptor (AHR) mediates the toxic effects of the environmental contaminant dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a range of toxic responses, including hepatic damage, steatohepatitis, and a lethal wasting syndrome; however, the mechanisms are still unknown. Here, we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (Tiparp), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity, steatohepatitis, and lethality. Tiparp−/− mice given a single injection of 100 μg/kg dioxin did not survive beyond day 5; all Tiparp+/+ mice survived the 30-day treatment. Dioxin-treated Tiparp−/− mice exhibited increased liver steatosis and hepatotoxicity. Tiparp ADP-ribosylated AHR but not its dimerization partner, the AHR nuclear translocator, and the repressive effects of TIPARP on AHR were reversed by the macrodomain containing mono-ADP-ribosylase MACROD1 but not MACROD2. These results reveal previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR-mediated steatohepatitis and lethality in response to dioxin. PMID:25975270

Dietary Omega-3 Polyunsaturated Fatty Acids Prevent Vascular Dysfunction and Attenuate Cytochrome P4501A1 Expression by 2,3,7,8-Tetrachlorodibenzo-P-Dioxin.

PubMed

Wiest, Elani F; Walsh-Wilcox, Mary T; Rothe, Michael; Schunck, Wolf-Hagen; Walker, Mary K

2016-11-01

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) found in fish protect against cardiovascular morbidity and mortality; however, many individuals avoid fish consumption due to concerns about pollutants. We tested the hypothesis that n-3 PUFAs would prevent vascular dysfunction induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). C57Bl/6 male mice were fed a chow or n-3 PUFA diet for 10 weeks and were exposed to vehicle or 300 ng/kg/d TCDD during the final 2 weeks on each diet. Aortic vasoconstriction mediated by arachidonic acid (AA) ± SKF525 (P450 inhibitor) or SQ29548 (thromboxane/prostanoid [TP] receptor antagonist) was assessed. RBC fatty acids and expression of n-3 and n-6 PUFA metabolites were analyzed. Cytochrome P4501A1 (CYP1A1), CYP1B1, and aryl hydrocarbon receptor (AHR) expression was measured. TCDD significantly increased AA-mediated vasoconstriction on a chow diet by increasing the contribution of P450s and TP receptor to the constriction response. In contrast, the n-3 PUFA diet prevented the TCDD-induced increase in AA vasoconstriction and normalized the contribution of P450s and TP receptor. Although TCDD increased the levels of AA vasoconstrictors on the chow diet, this increase was prevent by the n-3 PUFA diet. Additionally, the n-3 PUFA diet significantly increased the levels of n-3 PUFA-derived vasodilators and TCDD increased these levels further. Interestingly, the n-3 PUFA diet significantly attenuated CYP1A1 induction by TCDD without a significant effect on AHR expression. These data suggest that n-3 PUFAs can prevent TCDD-induced vascular dysfunction by decreasing vasoconstrictors, increasing vasodilators, and attenuating CYP1A1 induction, which has been shown previously to contribute to TCDD-induced vascular dysfunction. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

Hwang, Hye Jin

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor within the Per-Arnt-Sim (PAS) domain superfamily. Exposure to the most potent AHR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is associated with various pathological effects including metabolic syndrome. While research over the last several years has demonstrated a role for oxidative stress and metabolic dysfunction in AHR-dependent TCDD-induced toxicity, the role of the mitochondria in this process has not been fully explored. Our previous research suggested that a portion of the cellular pool of AHR could be found in the mitochondria (mitoAHR). Using a protease protection assay with digitonin extraction, we have now shownmore » that this mitoAHR is localized to the inter-membrane space (IMS) of the organelle. TCDD exposure induced a degradation of mitoAHR similar to that of cytosolic AHR. Furthermore, siRNA-mediated knockdown revealed that translocase of outer-mitochondrial membrane 20 (TOMM20) was involved in the import of AHR into the mitochondria. In addition, TCDD altered cellular respiration in an AHR-dependent manner to maintain respiratory efficiency as measured by oxygen consumption rate (OCR). Stable isotope labeling by amino acids in cell culture (SILAC) identified a battery of proteins within the mitochondrial proteome influenced by TCDD in an AHR-dependent manner. Among these, 17 proteins with fold changes ≥ 2 are associated with various metabolic pathways, suggesting a role of mitochondrial retrograde signaling in TCDD-mediated pathologies. Collectively, these studies suggest that mitoAHR is localized to the IMS and AHR-dependent TCDD-induced toxicity, including metabolic dysfunction, wasting syndrome, and hepatic steatosis, involves mitochondrial dysfunction. - Highlights: • The mitoAHR is localized in the mitochondrial intermembrane space. • TOMM20 participates in mitoAHR translocation. • AHR contributes to the maintenance of respiratory control ratio

A critical view of the mechanism(s) of toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin. Implications for human safety assessment.

PubMed

Rozman, K

1989-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been an important issue in occupational and environmental health for nearly two decades. During this period scientists have studied its possible impacts on exposed human populations. At the same time enormous efforts were made to elucidate the mechanism of TCDD action in various biological models. This paper provides a critical view of the advances made towards understanding the mechanism of TCDD action. Major topics discussed include the Ah-receptor hypothesis, TCDD as a thyroid hormone agonist, TCDD and vitamin A deficiency, TCDD's effect on receptor regulation, and its effect on intermediary metabolism including related hormonal responses. Although the exact mechanism of TCDD action is not yet known, more information is available on the toxicity of this compound than perhaps on that of any other substance. This wealth of information allows important conclusions regarding the assessment of acute, as well as of chronic, toxicities of TCDD for humans. There is no documented case of human death as a result of exposure to TCDD. It appears that humans are acutely less sensitive to TCDD than some animal species. The cause of TCDD-induced lethality in rats is a progressive lethal hypoglycemia due to inhibition of gluconeogenesis. Regulation of this metabolic pathway is quite different amongst species, although primates share great similarities. The assumption that the cause of TCDD-induced death in primates, in analogy to rats, is inhibition of gluconeogenesis would suggest that the acute toxicity of TCDD in humans would be in the range seen in rhesus monkeys (70-300 micrograms/kg). These values are about midway between the most (guinea pig) and least (hamster) sensitive species. TCDD is not a genotoxic agent and not an initiator, but promoter of tumor formation. There is considerable evidence that promotion of cancer, like any other chronic end point of toxicity, is a threshold-type biological process. Therefore, a linear

Perinatal development of conjugative enzyme systems.

PubMed Central

Lucier, G W

1976-01-01

The problems and priorities involved in studying the role of conjugagive enzymes in developmental pharmacology are discussed and evaluated. The relative rates of UDP glucuronyltransferase and beta-glucuronidase were studied during perinatal development in hepatic and extrahepatic tissues to determine the net balance of glucuronidation or deglucuronidation at different developmental stages. In general, deglucuronidation predominated over glucuronidation in fetal tissues whereas the converse was evident in adults. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an extremely toxic contaminant of some organochlorine compounds, was shown to be a potent inducer of some hepatic and extrahepatic drug-metabolizing enzymes. TCDD, administered during gestation, induced the postnatal activities of p-nitrophenol glucuronyltransferase and benzpyrene hydroxylase in rats. Foster mother experiments revealed that the postnatal induction was caused primarily by newborn exposure to TCDD in the mother's milk. Tissue distribution experiments with TCDD-14C confirmed these findings. Although TCDD induced non-steroid glucuronidation, no significant effects were evident on the postnatal development of steroid glucuronidation. The synthetic estrogen diethylstilbestrol (DES) is metabolized primarily by glucuronidation. The postnatal development of DES glucuronidation, like the steroid pathway, was not affected by gestational TCDD treatment. The fetal distribution of DES and DES-glucuronide, at different stages of development, correlated well with the perinatal development of steroid glucuronyltransferase activity. PMID:829487

Matrix Stiffness Corresponding to Strictured Bowel Induces a Fibrogenic Response in Human Colonic Fibroblasts

PubMed Central

Johnson, Laura A.; Rodansky, Eva S.; Sauder, Kay L.; Horowitz, Jeffrey C.; Mih, Justin D.; Tschumperlin, Daniel J.; Higgins, Peter D.

2013-01-01

Background Crohn’s disease is characterized by repeated cycles of inflammation and mucosal healing which ultimately progress to intestinal fibrosis. This inexorable progression towards fibrosis suggests that fibrosis becomes inflammation-independent and auto-propagative. We hypothesized that matrix stiffness regulates this auto-propagation of intestinal fibrosis. Methods The stiffness of fresh ex vivo samples from normal human small intestine, Crohn’s disease strictures, and the unaffected margin were measured with a microelastometer. Normal human colonic fibroblasts were cultured on physiologically normal or pathologically stiff matrices corresponding to the physiological stiffness of normal or fibrotic bowel. Cellular response was assayed for changes in cell morphology, α-smooth muscle actin (αSMA) staining, and gene expression. Results Microelastometer measurements revealed a significant increase in colonic tissue stiffness between normal human colon and Crohn’s strictures as well as between the stricture and adjacent tissue margin. In Ccd-18co cells grown on stiff matrices corresponding to Crohn’s strictures, cellular proliferation increased. Pathologic stiffness induced a marked change in cell morphology and increased αSMA protein expression. Growth on a stiff matrix induced fibrogenic gene expression, decreased matrix metalloproteinase and pro-inflammatory gene expression, and was associated with nuclear localization of the transcriptional cofactor MRTF-A. Conclusions Matrix stiffness, representative of the pathological stiffness of Crohn’s strictures, activates human colonic fibroblasts to a fibrogenic phenotype. Matrix stiffness affects multiple pathways suggesting the mechanical properties of the cellular environment are critical to fibroblast function and may contribute to autopropagation of intestinal fibrosis in the absence of inflammation, thereby contributing to the intractable intestinal fibrosis characteristic of Crohn’s disease. PMID

Pirfenidone inhibits transforming growth factor β1-induced extracellular matrix production in nasal polyp-derived fibroblasts.

PubMed

Shin, Jae-Min; Park, Joo-Hoo; Park, Il-Ho; Lee, Heung-Man

2015-01-01

Pirfenidone has been shown to have antifibrotic and anti-inflammatory effects in the lungs. The purpose of this study was to evaluate the inhibitory effects of pirfenidone on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and extracellular matrix accumulation. We also determined the molecular mechanisms of pirfenidone in nasal polyp-derived fibroblasts (NPDF). NPDFs were isolated from nasal polyps from eight patients who had chronic rhinosinusitis with nasal polyp. Pirfenidone was used to treat TGF-β1-induced NPDFs. Cytotoxicity was evaluated by using a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Fibroblast migration was evaluated with scratch assays. Expression levels of α-smooth muscle actin (SMA), fibronectin, and phosphorylated Smad2/3 were determined by Western blot and/or reverse transcription-polymerase chain reaction and immunofluorescent staining. Total collagen production was analyzed with the Sircol collagen assay and contractile activity was measured by a collagen gel contraction assay. Pirfenidone (0-2 mg/mL) has no significant cytotoxic effects in TGF-β1-induced NPDFs. Migration of NPDFs was significantly inhibited by pirfenidone treatment. The expression levels of α-SMA and fibronectin were significantly reduced in pirfenidone-treated NPDFs. Collagen contraction and production were also significantly decreased by pirfenidone treatment. Finally, pirfenidone significantly inhibited phosphorylation of the Smad2/3 pathway in TGF-β1-induced NPDFs. Pirfenidone has an inhibitory effect on TGF-β1-induced migration, myofibroblast differentiation (α-SMA), extracellular matrix accumulation, and collagen contraction by blocking the phosphorylation of Smad2/3 pathways in NPDFs. Thus, pirfenidone may inhibit TGF-β1-induced extracellular matrix by regulating Smad2/3.

Loss of Matrix Metalloproteinase-13 Attenuates Murine Radiation-Induced Pulmonary Fibrosis

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

Flechsig, Paul; Hartenstein, Bettina; Teurich, Sybille

2010-06-01

Purpose: Pulmonary fibrosis is a disorder of the lungs with limited treatment options. Matrix metalloproteinases (MMPs) constitute a family of proteases that degrade extracellular matrix with roles in fibrosis. Here we studied the role of MMP13 in a radiation-induced lung fibrosis model using a MMP13 knockout mouse. Methods and Materials: We investigated the role of MMP13 in lung fibrosis by investigating the effects of MMP13 deficiency in C57Bl/6 mice after 20-Gy thoracic irradiation (6-MV Linac). The morphologic results in histology were correlated with qualitative and quantitative results of volume computed tomography (VCT), magnetic resonance imaging (MRI), and clinical outcome. Results:more » We found that MMP13 deficient mice developed less pulmonary fibrosis than their wildtype counterparts, showed attenuated acute pulmonary inflammation (days after irradiation), and a reduction of inflammation during the later fibrogenic phase (5-6 months after irradiation). The reduced fibrosis in MMP13 deficient mice was evident in histology with reduced thickening of alveolar septi and reduced remodeling of the lung architecture in good correlation with reduced features of lung fibrosis in qualitative and quantitative VCT and MRI studies. The partial resistance of MMP13-deficient mice to fibrosis was associated with a tendency towards a prolonged mouse survival. Conclusions: Our data indicate that MMP13 has a role in the development of radiation-induced pulmonary fibrosis. Further, our findings suggest that MMP13 constitutes a potential drug target to attenuate radiation-induced lung fibrosis.« less

Osteoblasts extracellular matrix induces vessel like structures through glycosylated collagen I

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

Palmieri, D.; Valli, M.; Viglio, S.

2010-03-10

Extracellular matrix (ECM) plays a fundamental role in angiogenesis affecting endothelial cells proliferation, migration and differentiation. Vessels-like network formation in vitro is a reliable test to study the inductive effects of ECM on angiogenesis. Here we utilized matrix deposed by osteoblasts as substrate where the molecular and structural complexity of the endogenous ECM is preserved, to test if it induces vessel-like network formation by endothelial cells in vitro. ECM is more similar to the physiological substrate in vivo than other substrates previously utilized for these studies in vitro. Osteogenic ECM, prepared in vitro from mature osteoblasts at the phase ofmore » maximal deposition and glycosylation of collagen I, induces EAhy926, HUVEC, and HDMEC endothelial cells to form vessels-like structures and promotes the activation of metalloproteinase-2 (MMP-2); the functionality of the p-38/MAPK signaling pathway is required. Osteogenic ECM also induces a transient increase of CXCL12 and a decrease of the receptor CXCR4. The induction of vessel-like networks is dependent from proper glycosylation of collagens and does not occur on osteogenic ECMs if deglycosylated by -galactosidase or on less glycosylated ECMs derived from preosteoblasts and normal fibroblasts, while is sustained on ECM from osteogenesis imperfecta fibroblasts only when their mutation is associated with over-glycosylation of collagen type I. These data support that post-translational glycosylation has a role in the induction in endothelial cells in vitro of molecules conductive to self-organization in vessels-like structures.« less

The aryl hydrocarbon receptor-mediated disruption of vitellogenin synthesis in the fish liver: Cross-talk between AHR- and ERα-signalling pathways

PubMed Central

Bemanian, Vahid; Male, Rune; Goksøyr, Anders

2004-01-01

Background In the fish liver, the synthesis of egg yolk protein precursor vitellogenin (VTG) is under control of the estrogen receptor alpha (ERα). Environmental contaminants such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) are suspected to have antiestrogenic effects. The aryl hydrocarbon receptor (AHR) is the initial cellular target for TCDD and related compounds. The AHR is a ligand-activated transcription factor that stimulates the expression of the genes encoding xenobiotic metabolizing enzymes, such as cytochrome P450 1A (CYP1A). In this study, the effects of activation of AHR on the hepatic expression of VTG and ERα genes, in primary cultured salmon hepatocytes, have been investigated. Results The expression of the genes encoding VTG and ERα were strongly induced by 17β-estradiol (E2). However, the expression of VTG was disrupted by exposure of the cells to TCDD while CYP1A expression was enhanced. The effect of TCDD on VTG and CYP1A expression was annulled by the AHR-inhibitor α-naphthoflavone. Furthermore, exposure of the cells to TCDD abolished E2-induced accumulation of ERα mRNA. The AHR-mediated inhibitory effects on the expression of the VTG and ERα genes may occur at transcriptional and/or post-transcriptional levels. Nuclear run-off experiments revealed that simultaneous exposure of the cells to E2 and TCDD strongly inhibited the initiation of transcription of the VTG and ERα genes. In addition, inhibition of RNA synthesis by actinomycin D treatment showed that post-transcriptional levels of VTG and ERα mRNAs were not significantly altered upon treatment of the cells with TCDD. These results suggested that activation of AHR may inhibit the transactivation capacity of the ERα. Further, electrophoretic mobility shift assays using nuclear extracts prepared from cells treated for one or two hours with E2, alone or in mixture with TCDD, showed a strong reduction in the DNA binding activities upon TCDD treatment. These results also suggested

Identification of the Aryl Hydrocarbon Receptor Target Gene TiPARP as a Mediator of Suppression of Hepatic Gluconeogenesis by 2,3,7,8-Tetrachlorodibenzo-p-dioxin and of Nicotinamide as a Corrective Agent for This Effect*

PubMed Central

Diani-Moore, Silvia; Ram, Payal; Li, Xintian; Mondal, Prosenjit; Youn, Dou Yeon; Sauve, Anthony A.; Rifkind, Arleen B.

2010-01-01

The environmental toxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, dioxin) produces diverse toxic effects including a lethal wasting syndrome whose hallmark is suppressed hepatic gluconeogenesis. All TCDD toxicities require activation of the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor. Whereas the mechanism for AHR induction of target genes is well understood, it is not known how AHR activation produces any TCDD toxicity. This report identifies for the first time an AHR target gene, TiPARP (TCDD-inducible poly(ADP-ribose) polymerase, PARP7) that can mediate a TCDD toxicity, i.e. suppression of hepatic gluconeogenesis. TCDD suppressed hepatic glucose production, expression of key gluconeogenic genes, phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase (G6Pase), and NAD+ levels, and increased PARP activity and TiPARP expression. TCDD also increased acetylation and ubiquitin-dependent proteosomal degradation of the peroxisome proliferator-activated receptor γ coactivator 1 α (PGC1α), a coactivator of PEPCK and G6Pase transcription. TiPARP overexpression reproduced TCDD effects on glucose output and NAD+ levels whereas TiPARP silencing diminished them. TiPARP overexpression also increased PGC1α acetylation and decreased PGC1α levels. In contrast, silencing of cytochromes P450 (CYP) 1A, main AHR-induced genes, did not alter TCDD suppression of gluconeogenesis. The vitamin B3 constituent, nicotinamide (NAM), prevented TCDD suppression of glucose output, NAD+, and gluconeogenic genes and stabilized PGC1α. The corrective effects of NAM could be attributed to increased NAD+ levels and suppression of AHR target gene induction. The results reveal that TiPARP can mediate a TCDD effect, that the AHR is linked to PGC1α function and stability and that NAM has novel AHR antagonist activity. PMID:20876576

Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

NASA Astrophysics Data System (ADS)

Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

1999-05-01

We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

Graphene nanoplatelets induced heterogeneous bimodal structural magnesium matrix composites with enhanced mechanical properties

PubMed Central

Xiang, Shulin; Wang, Xiaojun; Gupta, Manoj; Wu, Kun; Hu, Xiaoshi; Zheng, Mingyi

2016-01-01

In this work, graphene nanoplatelets (GNPs) reinforced magnesium (Mg) matrix composites were synthesised using the multi-step dispersion route. Well-dispersed but inhomogeneously distributed GNPs were obtained in the matrix. Compared with the monolithic alloy, the nanocomposites exhibited dramatically enhanced Young’s modulus, yield strength and ultimate tensile strength and relatively high plasticity, which mainly attributed to the significant heterogeneous laminated microstructure induced by the addition of GNPs. With increasing of the concentration of GNPs, mechanical properties of the composites were gradually improved. Especially, the strengthening efficiency of all the composites exceeded 100%, which was significantly higher than that of carbon nanotubes reinforced Mg matrix composites. The grain refinement and load transfer provided by the two-dimensional and wrinkled surface structure of GNPs were the dominated strengthening mechanisms of the composites. This investigation develops a new method for incorporating GNPs in metals for fabricating high-performance composites. PMID:27941839

Graphene nanoplatelets induced heterogeneous bimodal structural magnesium matrix composites with enhanced mechanical properties

NASA Astrophysics Data System (ADS)

Xiang, Shulin; Wang, Xiaojun; Gupta, Manoj; Wu, Kun; Hu, Xiaoshi; Zheng, Mingyi

2016-12-01

In this work, graphene nanoplatelets (GNPs) reinforced magnesium (Mg) matrix composites were synthesised using the multi-step dispersion route. Well-dispersed but inhomogeneously distributed GNPs were obtained in the matrix. Compared with the monolithic alloy, the nanocomposites exhibited dramatically enhanced Young’s modulus, yield strength and ultimate tensile strength and relatively high plasticity, which mainly attributed to the significant heterogeneous laminated microstructure induced by the addition of GNPs. With increasing of the concentration of GNPs, mechanical properties of the composites were gradually improved. Especially, the strengthening efficiency of all the composites exceeded 100%, which was significantly higher than that of carbon nanotubes reinforced Mg matrix composites. The grain refinement and load transfer provided by the two-dimensional and wrinkled surface structure of GNPs were the dominated strengthening mechanisms of the composites. This investigation develops a new method for incorporating GNPs in metals for fabricating high-performance composites.

Force-Induced Unfolding of Fibronectin in the Extracellular Matrix of Living Cells

PubMed Central

Smith, Michael L; Gourdon, Delphine; Little, William C; Kubow, Kristopher E; Eguiluz, R. Andresen; Luna-Morris, Sheila; Vogel, Viola

2007-01-01

Whether mechanically unfolded fibronectin (Fn) is present within native extracellular matrix fibrils is controversial. Fn extensibility under the influence of cell traction forces has been proposed to originate either from the force-induced lengthening of an initially compact, folded quaternary structure as is found in solution (quaternary structure model, where the dimeric arms of Fn cross each other), or from the force-induced unfolding of type III modules (unfolding model). Clarification of this issue is central to our understanding of the structural arrangement of Fn within fibrils, the mechanism of fibrillogenesis, and whether cryptic sites, which are exposed by partial protein unfolding, can be exposed by cell-derived force. In order to differentiate between these two models, two fluorescence resonance energy transfer schemes to label plasma Fn were applied, with sensitivity to either compact-to-extended conformation (arm separation) without loss of secondary structure or compact-to-unfolded conformation. Fluorescence resonance energy transfer studies revealed that a significant fraction of fibrillar Fn within a three-dimensional human fibroblast matrix is partially unfolded. Complete relaxation of Fn fibrils led to a refolding of Fn. The compactly folded quaternary structure with crossed Fn arms, however, was never detected within extracellular matrix fibrils. We conclude that the resting state of Fn fibrils does not contain Fn molecules with crossed-over arms, and that the several-fold extensibility of Fn fibrils involves the unfolding of type III modules. This could imply that Fn might play a significant role in mechanotransduction processes. PMID:17914904

Combined effect of fluoride and 2,3,7,8-tetrachlorodibenzo-p-dioxin on mouse dental hard tissue formation in vitro.

PubMed

Salmela, Eija; Lukinmaa, Pirjo-Liisa; Partanen, Anna-Maija; Sahlberg, Carin; Alaluusua, Satu

2011-08-01

Fluoride interferes with enamel matrix secretion and mineralization and dentin mineralization. The most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), also impairs dental hard tissue formation and mineralization in vitro and in vivo. Our aim was to investigate in vitro whether the combined effect of sodium fluoride (NaF) and TCDD on dental hard tissue formation is potentiative. For this purpose, mandibular first and second molar tooth germs of E18 mouse embryos were cultured for 5-12 days with NaF and TCDD alone at various concentrations (2.5, 5, 10, 12.5, 15, and 20 μM and 5, 10, 12.5, and 15 nM, respectively) to determine the highest concentrations, which alone cause no or negligible effects. Morphological changes were studied from the whole tooth photographs and histological tissue sections. The concentrations found were 15 μM for NaF and 10 nM for TCDD. While at these concentrations, the effects of NaF and TCDD alone were barely detectable, the effect of simultaneous exposure on dentin and enamel formation was overt; mineralization of predentin to dentin and enamel matrix secretion and mineralization were impaired. Immunohistochemical analysis revealed that the combined exposure modified amelogenin expression by odontoblasts. Morphology of ameloblasts and the expression of amelogenin indicated that ameloblasts were still secretory. The results show that NaF and TCDD have potentiative, harmful effects on the formation of dental hard tissues. Since children can be exposed to subclinical levels of fluoride and dioxins during early childhood, coincidently with mineralization of the first permanent teeth, this finding may have clinical significance.

UTILIZATION OF A PBPK MODEL TO PREDICT THE DISTRIBUTION OF 2, 3, 7-8 TETRACHLORODIBENZO-P-DIOXIN (TCDD) IN HUMANS DURING CRITICAL WINDOWS OF DEVELOPMENT

EPA Science Inventory

Utilization of A PBPK model to predict the distribution of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) in humans during critical windows of development.
C Emond1, MJ DeVito2 and LS Birnbaum2
1National Research Council, US EPA, ORD, NHEERL, (ETD, PK), RTP, NC, 27711, USA 2 US...

Protective effect of naringin on 3-nitropropionic acid-induced neurodegeneration through the modulation of matrix metalloproteinases and glial fibrillary acidic protein.

PubMed

Gopinath, Kulasekaran; Sudhandiran, Ganapasam

2016-01-01

Naringin (4',5,7-trihydroxy-flavonone-7-rhamnoglucoside), a flavonone present in grapefruit, has recently been reported to protect against neurodegeration, induced with 3-nitropropionic acid (3-NP), through its antioxidant, anti-inflammatory, and antiapoptotic properties. This study used a rat model of 3-NP-induced neurodegeneration to investigate the neuroprotective effects of naringin exerted by modulating the expression of matrix metalloproteinases and glial fibrillary acidic protein. Neurodegeneration was induced with 3-NP (10 mg/kg body mass, by intraperitoneal injection) once a day for 2 weeks, and induced rats were treated with naringin (80 mg/kg body mass, by oral gavage, once a day for 2 weeks). Naringin ameliorated the motor abnormalities caused by 3-NP, and reduced blood-brain barrier dysfunction by decreasing the expression of matrix metalloproteinases 2 and 9, along with increasing the expression of the tissue inhibitors of metalloproteinases 1 and 2 in 3-NP-induced rats. Further, naringin reduced 3-NP-induced neuroinflammation by decreasing the expression of nuclear factor-kappa B and glial fibrillary acidic protein. Thus, naringin exerts protective effects against 3-NP-induced neurodegeneration by ameliorating the expressions of matrix metalloproteinases and glial fibrillary acidic protein.

The Extracellular Matrix Protein TGFBI Induces Microtubule Stabilization and Sensitizes Ovarian Cancers to Paclitaxel

PubMed Central

Ahmed, Ahmed Ashour; Mills, Anthony D.; Ibrahim, Ashraf E.K.; Temple, Jillian; Blenkiron, Cherie; Vias, Maria; Massie, Charlie E.; Iyer, N. Gopalakrishna; McGeoch, Adam; Crawford, Robin; Nicke, Barbara; Downward, Julian; Swanton, Charles; Bell, Stephen D.; Earl, Helena M.; Laskey, Ronald A.; Caldas, Carlos; Brenton, James D.

2007-01-01

Summary The extracellular matrix (ECM) can induce chemotherapy resistance via AKT-mediated inhibition of apoptosis. Here, we show that loss of the ECM protein TGFBI (transforming growth factor beta induced) is sufficient to induce specific resistance to paclitaxel and mitotic spindle abnormalities in ovarian cancer cells. Paclitaxel-resistant cells treated with recombinant TGFBI protein show integrin-dependent restoration of paclitaxel sensitivity via FAK- and Rho-dependent stabilization of microtubules. Immunohistochemical staining for TGFBI in paclitaxel-treated ovarian cancers from a prospective clinical trial showed that morphological changes of paclitaxel-induced cytotoxicity were restricted to areas of strong expression of TGFBI. These data show that ECM can mediate taxane sensitivity by modulating microtubule stability. PMID:18068629

The extracellular matrix protein TGFBI induces microtubule stabilization and sensitizes ovarian cancers to paclitaxel.

PubMed

Ahmed, Ahmed Ashour; Mills, Anthony D; Ibrahim, Ashraf E K; Temple, Jillian; Blenkiron, Cherie; Vias, Maria; Massie, Charlie E; Iyer, N Gopalakrishna; McGeoch, Adam; Crawford, Robin; Nicke, Barbara; Downward, Julian; Swanton, Charles; Bell, Stephen D; Earl, Helena M; Laskey, Ronald A; Caldas, Carlos; Brenton, James D

2007-12-01

The extracellular matrix (ECM) can induce chemotherapy resistance via AKT-mediated inhibition of apoptosis. Here, we show that loss of the ECM protein TGFBI (transforming growth factor beta induced) is sufficient to induce specific resistance to paclitaxel and mitotic spindle abnormalities in ovarian cancer cells. Paclitaxel-resistant cells treated with recombinant TGFBI protein show integrin-dependent restoration of paclitaxel sensitivity via FAK- and Rho-dependent stabilization of microtubules. Immunohistochemical staining for TGFBI in paclitaxel-treated ovarian cancers from a prospective clinical trial showed that morphological changes of paclitaxel-induced cytotoxicity were restricted to areas of strong expression of TGFBI. These data show that ECM can mediate taxane sensitivity by modulating microtubule stability.

SUPPRESSION OF HUMORAL IMMUNE RESPONSES BY 2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN INTERCALATED IN SMECTITE CLAY

PubMed Central

Boyd, Stephen A.; Johnston, Cliff T.; Pinnavaia, Thomas J.; Kaminski, Norbert E.; Teppen, Brian J.; Li, Hui; Khan, Bushra; Crawford, Robert B.; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L.F.

2018-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. PMID:21994089

Cardiotrophin-1 Induces Matrix Metalloproteinase-1 in Human Aortic Endothelial Cells

PubMed Central

Tokito, Akinori; Jougasaki, Michihisa; Ichiki, Tomoko; Hamasaki, Shuichi

2013-01-01

Rupture of an atherosclerotic plaque is a key event in the development of cardiovascular disorders, in which matrix metalloproteinase-1 (MMP-1) plays a crucial role by degradation of extracellular matrix resulting in plaque instability. Cardiotrophin-1 (CT-1), a member of interleukin-6-type proinflammatory cytokines, has potent cardiovascular actions and is highly expressed in vascular endothelium, however its role in atherosclerosis has not been fully elucidated to date. The present study was designed to investigate whether CT-1 induces MMP-1 in human aortic endothelial cells (HAECs). Ribonuclease protection assay demonstrated that MMP-1 gene level in HAECs was enhanced by the treatment of CT-1 in a dose- and time-dependent manner. Immunocytochemical staining, Western immunoblot analysis and enzyme-linked immunosorbent assay revealed that CT-1 augmented MMP-1 protein synthesis and secretion. MMP-1 activity assay revealed that MMP-1 present in the supernatant of HAECs was exclusively precursor form. Casein zymography disclosed proteolytic activity in the supernatant of HAECs, which was enhanced by CT-1 treatment. Furthermore, pharmacological inhibitor study indicated the important roles of extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen-activated protein (MAP) kinase, c-Jun N-terminal kinase (JNK) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathways in mediating CT-1-induced MMP-1 gene and protein expression. These data reveal for the first time that CT-1 induces the proteolytic potential in HAECs by upregulating MMP-1 expression through ERK1/2, p38 MAP kinase, JNK and JAK/STAT pathways, and suggest that CT-1 may play an important role in the pathophysiology of atherosclerosis and plaque instability. PMID:23935888

Extracellular matrix metalloproteinase inducer (EMMPRIN) remodels the extracellular matrix through enhancing matrix metalloproteinases (MMPs) and inhibiting tissue inhibitors of MMPs expression in HPV-positive cervical cancer cells.

PubMed

Xu, Q; Cao, X; Pan, J; Ye, Y; Xie, Y; Ohara, N; Ji, H

2015-01-01

PUPOSE OF INVESTIGATION: To study the expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteinases (MMPs), and tissue inhibitors of MMP (TIMPs) in uterine cervical cancer cell lines in vitro. EMMPRIN, MMPs, and TIMPs expression were assessed by Western blot and real-time RT-PCR from cervical carcinoma SiHa, HeLa, and C33-A cells. EMMPRIN recombinant significantly increased MMP-2, MMP-9 protein and mRNA expression in SiHa and Hela cells, but not in C33-A cells by Western blot analysis and real-time RT-PCR. EMMPRIN recombinant significantly inhibited TIMP-1 protein and mRNA levels in SiHa and Hela cells, but not in C33-A cells. There was no difference on the TIMP-2 expression in those cells with the treatment of EMMPRIN recombinant. EMMPRIN RNAi decreased MMP-2 and MMP-9 and increased TIMP-1 expression in SiHa and HeLa cells, but not in C33-A cells. There was no change on the expression of TIMP-2 mRNA levels in SiHa, HeLa and C33-A cells transfected with siEMMPRIN. EMMPRIN may induce MMP-2 and MMP-9, and downregulate TIMP-1 in HPV-positive cervical cancer cells in vitro.

Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Liaw, Benjamin; Zeichner, Glenn; Liu, Yanxiong; Bowles, Kenneth J. (Technical Monitor)

2000-01-01

The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Currently, impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.

Doxycycline inhibits TGF-β1-induced extracellular matrix production in nasal polyp-derived fibroblasts.

PubMed

Shin, Jae-Min; Park, Joo-Hoo; Park, Il-Ho; Lee, Heung-Man

2016-03-01

Doxycycline has been shown to have antibacterial and anti-inflammatory effects and suppresses collagen biosynthesis. The purpose of this study was to evaluate the effects of doxycycline on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and extracellular matrix production in nasal polyp-derived fibroblasts (NPDFs). We also determined the molecular mechanisms of action for doxycycline. NPDFs were isolated from nasal polyps from 8 patients. Doxycycline was used to pretreat TGF-β1-induced NPDFs. Cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-tetrazolium bromide assay. Expression levels of α-smooth muscle actin (SMA) and fibronectin were measured using Western blot, reverse-transcription polymerase chain reaction, and immunofluorescence staining. Total collagen production was analyzed with the Sircol collagen assay, while mitogen-activated protein kinase (MAPK) and NF-κB activation were determined using Western blot analysis. Luciferase assay was used to evaluate the transcriptional activity of NF-κB. Although doxycycline (0 to 40 μg/mL) had no significant cytotoxic effects in TGF-β1-induced NPDFs, it significantly reduced the expression levels of α-SMA, fibronectin, and collagen in TGF-β1-induced NPDFs in a dose-dependent manner. Doxycycline also inhibited the TGF-β1-induced activation of p38, c-Jun NH2 -terminal kinase (JNK), and NF-κB, and its inhibitory effects were similar to those of the specific inhibitors for each. Doxycycline has an inhibitory effect on TGF-β1-induced myofibroblast differentiation and extracellular matrix production via the p38 and JNK/NF-κB signal pathways in NPDFs. © 2015 ARS-AAOA, LLC.

Activation of aryl hydrocarbon receptor regulates the LPS/IFNγ-induced inflammatory response by inducing ubiquitin-proteosomal and lysosomal degradation of RelA/p65.

PubMed

Domínguez-Acosta, O; Vega, L; Estrada-Muñiz, E; Rodríguez, M S; Gonzalez, F J; Elizondo, G

2018-06-21

Several studies have identified the aryl hydrocarbon receptor (AhR) as a negative regulator of the innate and adaptive immune responses. However, the molecular mechanisms by which this transcription factor exerts such modulatory effects are not well understood. Interaction between AhR and RelA/p65 has previously been reported. RelA/p65 is the major NFκB subunit that plays a critical role in immune responses to infection. The aim of the present study was to determine whether the activation of AhR disrupted RelA/p65 signaling in mouse peritoneal macrophages by decreasing its half-life. The data demonstrate that the activation of AhR by TCDD and β-naphthoflavone (β-NF) decreased protein levels of the pro-inflammatory cytokines TFN-α, IL-6 and IL-12 after macrophage activation with LPS/IFNγ. In an AhR-dependent manner, TCDD treatment induces RelA/p65 ubiquitination and proteosomal degradation, an effect dependent on AhR transcriptional activity. Activation of AhR also induced lysosome-like membrane structure formation in mouse peritoneal macrophages and RelA/p65 lysosome-dependent degradation. In conclusion, these results demonstrate that AhR activation promotes RelA/p65 protein degradation through the ubiquitin proteasome system, as well as through the lysosomes, resulting in decreased pro-inflammatory cytokine levels in mouse peritoneal macrophages. Copyright © 2018. Published by Elsevier Inc.

PKA-induced receptor activator of NF-kappaB ligand (RANKL) expression in vascular cells mediates osteoclastogenesis but not matrix calcification.

PubMed

Tseng, Wendy; Graham, Lucia S; Geng, Yifan; Reddy, Aneela; Lu, Jinxiu; Effros, Rita B; Demer, Linda; Tintut, Yin

2010-09-24

Vascular calcification is a predictor of cardiovascular mortality and is prevalent in patients with atherosclerosis and chronic renal disease. It resembles skeletal osteogenesis, and many bone cells as well as bone-related factors involved in both formation and resorption have been localized in calcified arteries. Previously, we showed that aortic medial cells undergo osteoblastic differentiation and matrix calcification both spontaneously and in response to PKA agonists. The PKA signaling pathway is also involved in regulating bone resorption in skeletal tissue by stimulating osteoblast-production of osteoclast regulating cytokines, including receptor-activator of nuclear κB ligand (RANKL) and interleukins. Therefore, we investigated whether PKA activators regulate osteoclastogenesis in aortic smooth muscle cells (SMC). Treatment of murine SMC with the PKA agonist forskolin stimulated RANKL expression at both mRNA and protein levels. Forskolin also stimulated expression of interleukin-6 but not osteoprotegerin (OPG), an inhibitor of RANKL. Consistent with these results, osteoclastic differentiation was induced when monocytic preosteoclasts (RAW264.7) were cocultured with forskolin-treated aortic SMC. Oxidized phospholipids also slightly induced RANKL expression in T lymphocytes, another potential source of RANKL in the vasculature. Because previous studies have shown that RANKL treatment alone induces matrix calcification of valvular and vascular cells, we next examined whether RANKL mediates forskolin-induced matrix calcification by aortic SMC. RANKL inhibition with OPG had little or no effect on osteoblastic differentiation and matrix calcification of aortic SMC. These findings suggest that, as in skeletal tissues, PKA activation induces bone resorptive factors in the vasculature and that aortic SMC calcification specifically induced by PKA, is not mediated by RANKL.

Effect of anthocyanins on expression of matrix metalloproteinase-2 in naproxen-induced gastric ulcers.

PubMed

Kim, Sun-Joong; Park, Young Sam; Paik, Hyun-Dong; Chang, Hyo Ihl

2011-12-01

Non-steroidal anti-inflammatory drugs cause gastric ulceration through a number of mechanisms including inhibition of PG synthesis, generation of reactive oxygen species (ROS) and induction of apoptosis. Recently, matrix metalloproteinases (MMP) have been suggested to play a crucial role in these mechanisms. The present study investigated the protective effect of anthocyanins isolated from black rice bran (Heugjinjubyeo) against naproxen-induced gastric mucosal injury in rats. The oral administration of anthocyanins (5, 25 or 50 mg/kg body weight) showed significant protection against naproxen (80 mg/kg body weight)-induced gastric ulcer and inhibited lipid peroxidation in the gastric mucosa. In addition, pretreatment with anthocyanins resulted in a significant increase in the activities of radical-scavenging enzymes such as superoxide dismutase, catalase and glutathione peroxidase. Also biochemical and zymographic analyses suggested that the administration of anthocyanins gives a significant protection against naproxen-induced gastric antral ulcer through scavenging ROS and regulation of matrix metalloproteinase-2 (MMP-2) activity. The results of intracellular radical activation show that anthocyanins suppress the generation of intracellular ROS and attenuate the suppression of MMP-2 activity by naproxen. These results suggest that anthocyanins extracted from black rice may offer potential remedy of gastric antral ulceration.

Suppression of humoral immune responses by 2,3,7,8-tetrachlorodibenzo-p-dioxin intercalated in smectite clay.

PubMed

Boyd, Stephen A; Johnston, Cliff T; Pinnavaia, Thomas J; Kaminski, Norbert E; Teppen, Brian J; Li, Hui; Khan, Bushra; Crawford, Robert B; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L F

2011-12-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. Copyright © 2011 SETAC.

Critical role of cyclooxygenase-2 activation in pathogenesis of hydronephrosis caused by lactational exposure of mice to dioxin

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

Nishimura, Noriko; Matsumura, Fumio; Vogel, Christopher F.A.

2008-09-15

Congenital hydronephrosis is a serious disease occurring among infants and children. Besides the intrinsic genetic factors, in utero exposure to a xenobiotic, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has been suggested to induce hydronephrosis in rodents owing to anatomical obstruction in the ureter. Here, we report that hydronephrosis induced in mouse pups exposed lactationally to TCDD is not associated with anatomical obstruction, but with abnormal alterations in the subepithelial mesenchyma of the ureter. In the kidneys of these pups, the expressions of a battery of inflammatory cytokines including monocyte chemoattractant protein (MCP)-1, tumor necrosis factor {alpha} (TNF{alpha}) and interleukin (IL) -1{beta} were up-regulated asmore » early as postnatal day (PND) 7. The amounts of cyclooxygenase (COX) -2 mRNA and protein as well as prostaglandin E2 (PGE{sub 2}) were conspicuously up-regulated in an arylhydrocarbon-receptor-dependent manner in the TCDD-induced hydronephrotic kidney, with a subsequent down-regulation of the gene expressions of Na{sup +} and K{sup +} transporters, NKCC2 and ROMK. Daily administration of a COX-2 selective inhibitor to newborns until PND 7 completely abrogated the TCDD-induced PGE{sub 2} synthesis and gene expressions of inflammatory cytokines and electrolyte transporters, and eventually prevented the onset of hydronephrosis. These findings suggest an essential role of COX-2 in mediating the TCDD action of inducing hydronephrosis through the functional impairment rather than the anatomical blockade of the ureter.« less

Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Liaw, Benjamin; Villars, Esther; Delmont, Frantz; Bowles, Kenneth J. (Technical Monitor)

2001-01-01

The main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Impact-induced damage mechanisms in GLARE and ARALL fiber-metal laminates subject to instrumented drop-weight impacts at various temperatures were studied. GLARE and ARALL are hybrid composites made of alternating layers of aluminum and glass (for GLARE) and aramid- (for ARALL) fiber-reinforced epoxy. Damage in pure aluminum panels impacted by foreign objects was mainly characterized by large plastic deformation surrounding a deep penetration dent. On the other hand, plastic deformation in fiber-metal laminates was often not as severe although the penetration dent was still produced. The more stiff fiber-reinforced epoxy layers provided better bending rigidity; thus, enhancing impact damage tolerance. Severe cracking, however, occurred due to the use of these more brittle fiber-reinforced epoxy layers. Fracture patterns, e.g., crack length and delamination size, were greatly affected by the lay-up configuration rather than by the number of layers, which implies that thickness effect was not significant for the panels tested in this study. Immersion ultrasound techniques were then used to assess damages generated by instrumented drop-weight impacts onto these fiber-metal laminate panels as well as 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy. Depending on several parameters, such as impact velocity, mass, temperature, laminate configuration, sandwich construction, etc., various types of impact damage were observed, including plastic deformation, radiating cracks emanating from the impact site

Kidney stone matrix proteins ameliorate calcium oxalate monohydrate induced apoptotic injury to renal epithelial cells.

PubMed

Narula, Shifa; Tandon, Simran; Singh, Shrawan Kumar; Tandon, Chanderdeep

2016-11-01

Kidney stone formation is a highly prevalent disease, affecting 8-10% of the human population worldwide. Proteins are the major constituents of human kidney stone's organic matrix and considered to play critical role in the pathogenesis of disease but their mechanism of modulation still needs to be explicated. Therefore, in this study we investigated the effect of human kidney stone matrix proteins on the calcium oxalate monohydrate (COM) mediated cellular injury. The renal epithelial cells (MDCK) were exposed to 200μg/ml COM crystals to induce injury. The effect of proteins isolated from human kidney stone was studied on COM injured cells. The alterations in cell-crystal interactions were examined by phase contrast, polarizing, fluorescence and scanning electron microscopy. Moreover, its effect on the extent of COM induced cell injury, was quantified by flow cytometric analysis. Our study indicated the antilithiatic potential of human kidney stone proteins on COM injured MDCK cells. Flow cytometric analysis and fluorescence imaging ascertained that matrix proteins decreased the extent of apoptotic injury caused by COM crystals on MDCK cells. Moreover, the electron microscopic studies of MDCK cells revealed that matrix proteins caused significant dissolution of COM crystals, indicating cytoprotection against the impact of calcium oxalate injury. The present study gives insights into the mechanism implied by urinary proteins to restrain the pathogenesis of kidney stone disease. This will provide a better understanding of the formation of kidney stones which can be useful for the proper management of the disease. Copyright © 2016 Elsevier Inc. All rights reserved.

2,3,7,8-Tetrachlorodibenzo-p-dioxin specifically reduces mRNA for the mineralization-related dentin sialophosphoprotein in cultured mouse embryonic molar teeth

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

Kiukkonen, Anu; Sahlberg, Carin; Lukinmaa, Pirjo-Liisa

2006-11-01

Previous studies show that the most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), interferes with mineralization of the dental matrices in developing mouse and rat teeth. Culture of mouse embryonic molar teeth with TCDD leads to the failure of enamel to be deposited and dentin to undergo mineralization. Lactationally exposed rats show defectively matured enamel and retardation of dentin mineralization. To see if the impaired mineralization is associated with changes in the expression of dentin sialophosphoprotein (Dspp), Bono1 and/or matrix metalloproteinase-20 (MMP-20), thought to be involved in mineralization of the dental hard tissues, we cultured mouse (NMRI) E18 mandibular molars for 3,more » 5 or 7 days and exposed them to 1 {mu}M TCDD after 2 days of culture. As detected by in situ hybridization of tissue sections, localization and intensity of Bono1 and MMP-20 expression showed no definite difference between the control and exposed tooth explants, suggesting that TCDD does not affect their expression. On the contrary, TCDD reduced or prevented the expression of Dspp in secretory odontoblasts and decreased it in presecretory ameloblasts. The results suggest that the retardation of dentin mineralization by TCDD in mouse molar teeth involves specific interference with Dspp expression.« less

Specific Caleosin/Peroxygenase and Lipoxygenase Activities Are Tissue-Differentially Expressed in Date Palm (Phoenix dactylifera L.) Seedlings and Are Further Induced Following Exposure to the Toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin.

PubMed

Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad; Rahman, Farzana; Hassan, Mehedi; Murphy, Denis J

2016-01-01

Two caleosin/peroxygenase isoforms from date palm, Phoenix dactylifera L., PdCLO2 and PdCLO4, were characterized with respect to their tissue expression, subcellular localization, and oxylipin pathway substrate specificities in developing seedlings. Both PdCLO2 and PdCLO4 had peroxygenase activities that peaked at the mid-stage (radicle length of 2.5 cm) of seedling growth and were associated with the lipid droplet (LD) and microsomal fractions. Recombinant PdCLO2 and PdCLO4 proteins heterologously expressed in yeast cells were localized in both LD and microsomal fractions. Each of the purified recombinant proteins exhibited peroxygenase activity but they were catalytically distinct with respect to their specificity and product formation from fatty acid epoxide and hydroxide substrates. We recently showed that date palm CLO genes were upregulated following exposure to the potent toxin, 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) (Hanano et al., 2016), and we show here that transcripts of 9- and 13-lipoxygenase (LOX) genes were also induced by TCDD exposure. At the enzyme level, 9-LOX and 13-LOX activities were present in a range of seedling tissues and responded differently to TCDD exposure, as did the 9- and 13-fatty acid hydroperoxide reductase activities. This demonstrates that at least two branches of the oxylipin pathway are involved in responses to the environmental organic toxin, TCDD in date palm.

Specific Caleosin/Peroxygenase and Lipoxygenase Activities Are Tissue-Differentially Expressed in Date Palm (Phoenix dactylifera L.) Seedlings and Are Further Induced Following Exposure to the Toxin 2,3,7,8-tetrachlorodibenzo-p-dioxin

PubMed Central

Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad; Rahman, Farzana; Hassan, Mehedi; Murphy, Denis J.

2017-01-01

Two caleosin/peroxygenase isoforms from date palm, Phoenix dactylifera L., PdCLO2 and PdCLO4, were characterized with respect to their tissue expression, subcellular localization, and oxylipin pathway substrate specificities in developing seedlings. Both PdCLO2 and PdCLO4 had peroxygenase activities that peaked at the mid-stage (radicle length of 2.5 cm) of seedling growth and were associated with the lipid droplet (LD) and microsomal fractions. Recombinant PdCLO2 and PdCLO4 proteins heterologously expressed in yeast cells were localized in both LD and microsomal fractions. Each of the purified recombinant proteins exhibited peroxygenase activity but they were catalytically distinct with respect to their specificity and product formation from fatty acid epoxide and hydroxide substrates. We recently showed that date palm CLO genes were upregulated following exposure to the potent toxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (Hanano et al., 2016), and we show here that transcripts of 9- and 13-lipoxygenase (LOX) genes were also induced by TCDD exposure. At the enzyme level, 9-LOX and 13-LOX activities were present in a range of seedling tissues and responded differently to TCDD exposure, as did the 9- and 13-fatty acid hydroperoxide reductase activities. This demonstrates that at least two branches of the oxylipin pathway are involved in responses to the environmental organic toxin, TCDD in date palm. PMID:28111588

Comparison of aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase induction by polycyclic aromatic compounds in human and mouse cell lines.

PubMed

Jaiswal, A K; Nebert, D W; Eisen, H W

1985-08-01

The human MCF-7 and the mouse Hepa-1 cell culture lines were compared for aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase inducibility by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and benzo[a]anthracene (BA) and TCDD- and BA-specific binding in the cytosol and nucleus. The effective concentration of BA in the growth medium required to induce either enzyme to 50% of its maximally inducible activity (EC50) was the same (5-11 microM) in both MCF-7 and Hepa-1 cells. On the other hand, the EC50 for TCDD in MCF-7 cells (5-25 nM) was more than 40-fold greater than that in Hepa-1 cells (0.4 to 0.6 nM). P1-450- and P3-450-specific mouse cDNA probes were used to quantitate mRNA induction in the Hepa-1 cell line. P1-450 mRNA was induced markedly by TCDD and benzo[a] anthracene, whereas P3-450 mRNA was induced negligibly. A P1-450-specific human cDNA probe was used to quantitate P1-450 mRNA induction in the MCF-7 cell line. Aryl hydrocarbon hydroxylase inducibility by TCDD or BA always paralleled P1-450 mRNA inducibility in either the mouse or human line. Although the cytosolic Ah receptor in Hepa-1 cells was easily detected by sucrose density gradient centrifugation, gel permeation chromatography, and anion-exchange high-performance liquid chromatography, the cytosolic receptor cannot be detected in MCF-7 cells. Following in vivo exposure of cultures to radiolabeled TCDD, the intranuclear concentration of inducer-receptor complex was at least fifty times greater in Hepa-1 than MCF-7 cultures. The complete lack of measurable cytosolic receptor and almost totally absent inducer-receptor complex in the nucleus of MCF-7 cells was, therefore, out of proportion to its capacity for aryl hydrocarbon hydroxylase and acetanilide 4-hydroxylase inducibility. This MCF-7 line should provide an interesting model for a better understanding of the mechanisms of drug-metabolizing enzyme induction by polycyclic aromatic compounds, including the Ah receptor-mediated mechanism.

Lower concentrations of receptor for advanced glycation end products and epiregulin in amniotic fluid correlate to chemically induced cleft palate in mice.

PubMed

Wang, Xinhuan; Zhu, Jingjing; Fang, Yanjun; Bian, Zhuan; Meng, Liuyan

2017-04-01

This study investigated the correlation between differentially expressed proteins in amniotic fluid (AF) and cleft palate induced by all-trans retinoic acid (atRA), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. Seven proteins were differentially expressed at embryonic day (E) 16.5 in atRA and control groups as revealed by label-based mouse antibody array. Enzyme-linked immunosorbent assay was further used to detect the expression levels of these proteins in AF from E13.5 to E16.5 in atRA, TCDD, and control groups. The cleft palate groups showed lower concentrations of receptor for advanced glycation end products (RAGE) and epiregulin at E16.5. RAGE immunostaining obviously decreased in palatal tissue sections obtained from E14.5 to E16.5 in the cleft palate groups as revealed by immunohistochemistry. These findings indicate that reduced levels of RAGE and epiregulin in AF are correlated to chemically induced cleft palate in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

The extracellular matrix metalloproteinase inducer EMMPRIN is a target of nitric oxide in myocardial ischemia/reperfusion.

PubMed

Tarin, Carlos; Lavin, Begoña; Gomez, Monica; Saura, Marta; Diez-Juan, Antonio; Zaragoza, Carlos

2011-07-15

Nitric oxide (NO) is an important defense against myocardial ischemia/reperfusion (I/R) injury. Although matrix metalloproteinase (MMP)-mediated necrosis of cardiac myocytes is well characterized, the role of inducible NO synthase (iNOS)-derived NO in this process is poorly understood. I/R injury was increased in iNOS-deficient mice and in mice treated with 1400 W (a pharmacological iNOS inhibitor) and was associated with significantly increased expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and EMMPRIN-associated MMPs. Transcriptional activity of an EMMPRIN luciferase promoter reporter expressed in cardiac myocytes was inhibited by NO in a cGMP-dependent manner, and this transcriptional inhibition was abolished by mutation of a putative E2F site. Consistent with these findings, EMMPRIN null mice, in which iNOS is normally induced, are partially protected against I/R injury. Pharmacological inhibition of iNOS in EMMPRIN null mice had no additional protective effect, suggesting that EMMPRIN is a downstream target of NO. Administration of anti-EMMPRIN neutralizing antibodies partly reduced the excess heart damage and MMP-9 expression induced by I/R in iNOS null mice, indicating that regulation of EMMPRIN is an important mechanism of NO-mediated cardioprotection. Copyright © 2011 Elsevier Inc. All rights reserved.

Prediction of thermal cycling induced cracking in polmer matrix composites

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1994-01-01

The work done in the period August 1993 through February 1994 on the 'Prediction of Thermal Cycling Induced Cracking In Polymer Matrix Composites' program is summarized. Most of the work performed in this period, as well as the previous one, is described in detail in the attached Master's thesis, 'Analysis of Thermally Induced Damage in Composite Space Structures,' by Cecelia Hyun Seon Park. Work on a small thermal cycling and aging chamber was concluded in this period. The chamber was extensively tested and calibrated. Temperatures can be controlled very precisely, and are very uniform in the test chamber. Based on results obtained in the previous period of this program, further experimental progressive cracking studies were carried out. The laminates tested were selected to clarify the differences between the behaviors of thick and thin ply layers, and to explore other variables such as stacking sequence and scaling effects. Most specimens tested were made available from existing stock at Langley Research Center. One laminate type had to be constructed from available prepreg material at Langley Research Center. Specimens from this laminate were cut and prepared at MIT. Thermal conditioning was carried out at Langley Research Center, and at the newly constructed MIT facility. Specimens were examined by edge inspection and by crack configuration studies, in which specimens were sanded down in order to examine the distribution of cracks within the specimens. A method for predicting matrix cracking due to decreasing temperatures and/or thermal cycling in all plies of an arbitrary laminate was implemented as a computer code. The code also predicts changes in properties due to the cracking. Extensive correlations between test results and code predictions were carried out. The computer code was documented and is ready for distribution.

Synergistic cellular effects including mitochondrial destabilization, autophagy and apoptosis following low-level exposure to a mixture of lipophilic persistent organic pollutants.

PubMed

Rainey, Nathan E; Saric, Ana; Leberre, Alexandre; Dewailly, Etienne; Slomianny, Christian; Vial, Guillaume; Zeliger, Harold I; Petit, Patrice X

2017-07-05

Humans are exposed to multiple exogenous environmental pollutants. Many of these compounds are parts of mixtures that can exacerbate harmful effects of the individual mixture components. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is primarily produced via industrial processes including incineration and the manufacture of herbicides. Both endosulfan and TCDD are persistent organic pollutants which elicit cytotoxic effects by inducing reactive oxygen species generation. Sublethal concentrations of mixtures of TCDD and endosulfan increase oxidative stress, as well as mitochondrial homeostasis disruption, which is preceded by a calcium rise and, in fine, induce cell death. TCDD+Endosulfan elicit a complex signaling sequence involving reticulum endoplasmic destalilization which leads to Ca 2+ rise, superoxide anion production, ATP drop and late NADP(H) depletion associated with a mitochondrial induced apoptosis concomitant early autophagic processes. The ROS scavenger, N-acetyl-cysteine, blocks both the mixture-induced autophagy and death. Calcium chelators act similarly and mitochondrially targeted anti-oxidants also abrogate these effects. Inhibition of the autophagic fluxes with 3-methyladenine, increases mixture-induced cell death. These findings show that subchronic doses of pollutants may act synergistically. They also reveal that the onset of autophagy might serve as a protective mechanism against ROS-triggered cytotoxic effects of a cocktail of pollutants in Caco-2 cells and increase their tumorigenicity.

Regulation of Bach2 by the Aryl-hydrocarbon Receptor as a Mechanism for Suppression of B-cell Differentiation by 2,3,7,8-Tetrachlorodibenzo-p-dioxin

PubMed Central

De Abrew, K. Nadira; Phadnis, Ashwini S.; Crawford, Robert B.; Kaminski, Norbert E.; Thomas, Russell S.

2011-01-01

Exposure to the aryl hydrocarbon receptor (AHR) agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), alters B cell differentiation and suppresses antibody production. Previous genomic studies in mouse B cells identified Bach2 as a direct target of the AHR. Bach2 is known to repress expression of Prdm1, a key transcription factor involved in B cell differentiation, by binding to Maf elements (MAREs) in the regulatory regions of the gene. Chromatin immunopreciptiation followed by quantitative PCR in TCDD-treated lipopolysaccharide (LPS)-activated B cells showed increased binding of the AHR within the first intron in the Bach2 gene. The binding was further confirmed by electrophoretic mobility shift assay (EMSA). TCDD also induced expression of Bach2 in activated as well as resting B cells from 2 to 24 h post-treatment in a time and concentration-dependent manner. Expression of Prdm1 was decreased by TCDD at 24 h and was consistent with repression by Bach2. Increased DNA binding activity to the intron 5 MARE with increasing TCDD concentration was observed by EMSA. Supershifts identified the presence of Bach2 in the DNA binding complex associated with the intron5 MARE of Prdm1. Functional validation of the role of Bach2 in the suppression of B-cell differentiation by TCDD was performed using RNAi. Knockdown of Bach2 showed approximately 40% reversal in the TCDD-induced suppression of IgM secretion when compared to controls. The results suggest that the transcriptional regulation of Bach2 by the AHR is one of the mechanisms involved in the suppression of B-cell differentiation by TCDD. PMID:21296099

Developmental exposure to 2,3,7,8 tetrachlorodibenzo-p-dioxin attenuates later-life Notch1-mediated T cell development and leukemogenesis

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

Ahrenhoerster, Lori S.; Leuthner, Tess C.; Tate, Everett R.

2015-03-01

Over half of T cell acute lymphoblastic leukemia (T-ALL) patients have activating mutations in the Notch gene. Moreover, the contaminant 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is a known carcinogen that mediates its toxicity through the aryl hydrocarbon receptor (AHR), and crosstalk between activated AHR and Notch signaling pathways has previously been observed. Given the importance of Notch signaling in thymocyte development and T-ALL disease progression, we hypothesized that the activated AHR potentiates disease initiation and progression in an in vivo model of Notch1-induced thymoma. This hypothesis was tested utilizing adult and developmental exposure paradigms to TCDD in mice expressing a constitutively activemore » Notch1 transgene (Notch{sup ICN-TG}). Following exposure of adult Notch{sup ICN-TG} mice to a single high dose of TCDD, we observed a significant increase in the efficiency of CD8 thymocyte generation. We next exposed pregnant mice to 3 μg/kg of TCDD throughout gestation and lactation to elucidate effects of developmental AHR activation on later-life T cell development and T-ALL-like thymoma susceptibility induced by Notch1. We found that the vehicle-exposed Notch{sup ICN-TG} offspring have a peripheral T cell pool heavily biased toward the CD4 lineage, while TCDD-exposed Notch{sup ICN-TG} offspring were biased toward the CD8 lineage. Furthermore, while the vehicle-exposed NotchICN-TG mice showed increased splenomegaly and B to T cell ratios indicative of disease, mice developmentally exposed to TCDD were largely protected from disease. These studies support a model where developmental AHR activation attenuates later-life Notch1-dependent impacts on thymocyte development and disease progression. - Highlights: • Adult mice exposed to 30 μg/kg TCDD have higher efficiency of CD8 thymocyte generation. • Mice carrying a constitutively active Notch transgene were exposed to 3 μg/kg TCDD throughout development. • Progression of Notch-induced

α2 Integrin, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-3 act sequentially to induce differentiation of mouse embryonic stem cells into odontoblast-like cells

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

Ozeki, Nobuaki; Kawai, Rie; Hase, Naoko

We previously reported that interleukin 1β acts via matrix metalloproteinase (MMP)-3 to regulate cell proliferation and suppress apoptosis in α2 integrin-positive odontoblast-like cells differentiated from mouse embryonic stem (ES) cells. Here we characterize the signal cascade underpinning odontoblastic differentiation in mouse ES cells. The expression of α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and MMP-3 mRNA and protein were all potently increased during odontoblastic differentiation. Small interfering RNA (siRNA) disruption of the expression of these effectors potently suppressed the expression of the odontoblastic biomarkers dentin sialophosphoprotein, dentin matrix protein-1 and alkaline phosphatase, and blocked odontoblast calcification. Our siRNA, western blotmore » and blocking antibody analyses revealed a unique sequential cascade involving α2 integrin, Emmprin and MMP-3 that drives ES cell differentiation into odontoblasts. This cascade requires the interaction between α2 integrin and Emmprin and is potentiated by exogenous MMP-3. Finally, although odontoblast-like cells potently express α2, α6, αV, β1, and β3, integrins, we confirmed that β1 integrin acts as the trigger for ES cell differentiation, apparently in complex with α2 integrin. These results demonstrate a unique and unanticipated role for an α2 integrin-, Emmprin-, and MMP-3-mediated signaling cascade in driving mouse ES cell differentiation into odontoblast-like cells. - Highlights: • Odontoblast differentiation requires activation of α2 integrin, Emmprin and MMP-3. • α2 integrin, Emmprin and MMP-3 form a sequential signaling cascade. • β1 integrin acts a specific trigger for odontoblast differentiation. • The role of these effectors is highly novel and unanticipated.« less

Omentin-1 prevents cartilage matrix destruction by regulating matrix metalloproteinases.

PubMed

Li, Zhigang; Liu, Baoyi; Zhao, Dewei; Wang, BenJie; Liu, Yupeng; Zhang, Yao; Li, Borui; Tian, Fengde

2017-08-01

Matrix metalloproteinases (MMPs) play a crucial role in the degradation of the extracellular matrix and pathological progression of osteoarthritis (OA). Omentin-1 is a newly identified anti-inflammatory adipokine. Little information regarding the protective effects of omentin-1 in OA has been reported before. In the current study, our results indicated that omentin-1 suppressed expression of MMP-1, MMP-3, and MMP-13 induced by the proinflammatory cytokine interleukin-1β (IL-1β) at both the mRNA and protein levels in human chondrocytes. Importantly, administration of omentin-1 abolished IL-1β-induced degradation of type II collagen (Col II) and aggrecan, the two major extracellular matrix components in articular cartilage, in a dose-dependent manner. Mechanistically, omentin-1 ameliorated the expression of interferon regulatory factor 1 (IRF-1) by blocking the JAK-2/STAT3 pathway. Our results indicate that omentin-1 may have a potential chondroprotective therapeutic capacity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Comparison of destructive periodontal disease in blue iris mink to PCB 126-induced mandibular and maxillary squamous epithelial proliferation in natural dark mink.

PubMed

Ellick, Rachel M; Fitzgerald, Scott D; Link, Jane E; Bursian, Steven J

2013-01-01

Mink (Mustela vison) exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like chemicals have been reported to develop mandibular and maxillary squamous cell proliferation that results in the destruction of alveolar bone and eventual tooth loss. This jaw lesion has been reported in wild mink collected from areas contaminated with TCDD-like compounds and is a potential biomarker for exposure to these chemicals. The blue iris strain of domestic mink is prone to develop severe periodontal disease, which results in destruction of bone and tooth loss that is grossly similar to the lesion induced by exposure to TCDD-like chemicals. A histological assessment of jaws from blue iris mink and natural dark mink exposed to 3,3',4,4',5-pentachlorobiphenyl (PCB 126) was done to determine whether the oral lesions are similar. The jaw tissue from the blue iris mink had lesions indicative of lymphoplasmacytic gingivitis and osteomyelitis, caused by inflammation entering the dental sulcus, while the jaw tissue from the mink exposed to PCB 126 exhibited squamous epithelial proliferation. Therefore, it was determined that the tooth loss and bone destruction seen in these mink are of different origin despite the similarity of the gross clinical signs.

UV-tunable laser induced phototransformations of matrix isolated anethole.

PubMed

Krupa, Justyna; Wierzejewska, Maria; Nunes, Cláudio M; Fausto, Rui

2014-03-14

A matrix isolation study of the infrared spectra and structure of anethole (1-methoxy-4-(1-propenyl)benzene) has been carried out, showing the presence of two E conformers (AE1, AE2) of the molecule in the as-deposited matrices. Irradiation using ultraviolet-tunable laser light at 308-307 nm induced conformationally selective phototransformations of these forms into two less stable Z conformers (AZ1, AZ2). The back reactions were also detected upon irradiation at 301 nm. On the whole, the obtained results allow for full assignment of the infrared spectra of all the four experimentally observed anethole isomers and showed that the narrowband UV-induced E-Z photoisomerization is an efficient and selective way to interconvert the two isomers of anethole into each other, with conformational discrimination. Photolysis of anethole was observed as well, with initial methoxyl O-C bond cleavage and formation of CH3 and p-propenylphenoxy (AR) radicals, followed by radical recombination to form 2-methyl-4-propenyl-2,4-cyclohexadienone, which subsequently undergoes ring-opening generating several conformers of long-chain conjugated ketenes. Interpretation of the experimental observations was supported by density functional theory (B3LYP and B2PLYD) calculations.

Interference by 2,3,7,8-tetrachlorodibenzo-p-dioxin with cultured mouse submandibular gland branching morphogenesis involves reduced epidermal growth factor receptor signaling

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

Kiukkonen, Anu; Sahlberg, Carin; Partanen, Anna-Maija

2006-05-01

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to mouse embryonic teeth, sharing features of early development with salivary glands in common, involves enhanced apoptosis and depends on the expression of epidermal growth factor (EGF) receptor. EGF receptor signaling, on the other hand, is essential for salivary gland branching morphogenesis. To see if TCDD impairs salivary gland morphogenesis and if the impairment is associated with EGF receptor signaling, we cultured mouse (NMRI) E13 submandibular glands with TCDD or TCDD in combination with EGF or fibronectin (FN), both previously found to enhance branching morphogenesis. Explants were examined stereomicroscopically and processed to paraffin sections. TCDD exposuremore » impaired epithelial branching and cleft formation, resulting in enlarged buds. The glands were smaller than normal. EGF and FN alone concentration-dependently stimulated or inhibited branching morphogenesis but when co-administered with TCDD, failed to compensate for its effect. TCDD induced cytochrome P4501A1 expression in the glandular epithelium, indicating activation of the aryl hydrocarbon receptor. TCDD somewhat increased epithelial apoptosis as observed by terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labeling method but the increase could not be correlated with morphological changes. The frequency of proliferating cells was not altered. Corresponding to the reduced cleft sites in TCDD-exposed explants, FN immunoreactivity in the epithelium was reduced. The results show that TCDD, comparably with EGF and FN at morphogenesis-inhibiting concentrations, impaired salivary gland branching morphogenesis in vitro. Together with the failure of EGF and FN at morphogenesis-stimulating concentrations to compensate for the effect of TCDD this implies that TCDD toxicity to developing salivary gland involves reduced EGF receptor signaling.« less

Platelet-rich fibrin matrix improves wound angiogenesis via inducing endothelial cell proliferation.

PubMed

Roy, Sashwati; Driggs, Jason; Elgharably, Haytham; Biswas, Sabyasachi; Findley, Muna; Khanna, Savita; Gnyawali, Urmila; Bergdall, Valerie K; Sen, Chandan K

2011-11-01

The economic, social, and public health burden of chronic ulcers and other compromised wounds is enormous and rapidly increasing with the aging population. The growth factors derived from platelets play an important role in tissue remodeling including neovascularization. Platelet-rich plasma (PRP) has been utilized and studied for the last four decades. Platelet gel and fibrin sealant, derived from PRP mixed with thrombin and calcium chloride, have been exogenously applied to tissues to promote wound healing, bone growth, hemostasis, and tissue sealing. In this study, we first characterized recovery and viability of as well as growth factor release from platelets in a novel preparation of platelet gel and fibrin matrix, namely platelet-rich fibrin matrix (PRFM). Next, the effect of PRFM application in a delayed model of ischemic wound angiogenesis was investigated. The study, for the first time, shows the kinetics of the viability of platelet-embedded fibrin matrix. A slow and steady release of growth factors from PRFM was observed. The vascular endothelial growth factor released from PRFM was primarily responsible for endothelial mitogenic response via extracellular signal-regulated protein kinase activation pathway. Finally, this preparation of PRFM effectively induced endothelial cell proliferation and improved wound angiogenesis in chronic wounds, providing evidence of probable mechanisms of action of PRFM in healing of chronic ulcers. 2011 by the Wound Healing Society.

Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) promotes lung fibroblast proliferation, survival and differentiation to myofibroblasts.

PubMed

Hasaneen, Nadia A; Cao, Jian; Pulkoski-Gross, Ashleigh; Zucker, Stanley; Foda, Hussein D

2016-02-17

Idiopathic pulmonary fibrosis (IPF) is a chronic progressively fatal disease. Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) is a glycosylated transmembrane protein that induces the expression of some matrix metalloproteinase (MMP) in neighboring stromal cells through direct epithelial-stromal interactions. EMMPRIN is highly expressed in type II alveolar epithelial cells at the edges of the fibrotic areas in IPF lung sections. However, the exact role of EMMPRIN in IPF is unknown. To determine if EMMPRIN contributes to lung fibroblast proliferation, resistance to apoptosis, and differentiation to myofibroblasts, normal Human lung fibroblasts (NHLF) transiently transfected with either EMMPRIN/GFP or GFP were treated with TGF- β1 from 0 to 10 ng/ml for 48 h and examined for cell proliferation (thymidine incorporation), apoptosis (FACS analysis and Cell Death Detection ELISA assay), cell migration (Modified Boyden chamber) and differentiation to myofibroblasts using Western blot for α-smooth actin of cell lysates. The effect of EMMPRIN inhibition on NHLF proliferation, apoptosis, migration and differentiation to myofibroblasts after TGF- β1 treatment was examined using EMMPRIN blocking antibody. We examined the mechanism by which EMMPRIN induces its effects on fibroblasts by studying the β-catenin/canonical Wnt signaling pathway using Wnt luciferase reporter assays and Western blot for total and phosphorylated β-catenin. Human lung fibroblasts overexpressing EMMPRIN had a significant increase in cell proliferation and migration compared to control fibroblasts. Furthermore, EMMPRIN promoted lung fibroblasts resistance to apoptosis. Lung fibroblasts overexpressing EMMPRIN showed a significantly increased expression of α- smooth muscle actin, a marker of differentiation to myofibroblasts compared to control cells. TGF-β1 increased the expression of EMMPRIN in lung fibroblasts in a dose-dependent manner. Attenuation of EMMPRIN expression with the use of an

Nitric Oxide Induces Cardiac Protection by Preventing Extracellular Matrix Degradation through the Complex Caveolin-3/EMMPRIN in Cardiac Myocytes

PubMed Central

Cuadrado, Irene; Castejon, Borja; Martin, Ana M.; Saura, Marta; Reventun-Torralba, Paula; Zamorano, Jose Luis

2016-01-01

Inhibition of Extracellular Matrix degradation by nitric oxide (NO) induces cardiac protection against coronary ischemia/reperfusion (IR). Glycosylation of Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) stimulates enzymatic activation of matrix metalloproteinases (MMPs) in the heart, although the mechanisms leading to EMMPRIN glycosylation are poorly understood. We sought to determine if NO may induce cardiac protection by preventing glycosylation of EMMPRIN in a mouse model of IR. Here we found that Caveolin-3 binds to low glycosylated EMMPRIN (LG-EMMPRIN) in cardiac cells and in the hearts of healthy mice, whereas IR disrupted the complex in nitric oxide synthase 2 (NOS2) knockout (KO) mice. By contrast, the binding was partially restored when mice were fed with an NO donor (DEA-NO) in the drinking water, showing a significant reduction on infarct size (NOS2KO: 34.6±5 vs NOS2KO+DEA-NO: 20.7±9), in expression of matrix metalloproteinases, and cardiac performance was improved (left ventricular ejection fraction (LVEF). NOS2KO: 31±4 vs NOS2KO+DEA-NO: 46±6). The role of Caveolin-3/EMMPRIN in NO-mediated cardiac protection was further assayed in Caveolin-3 KO mice, showing no significant improvement on infarct size (Caveolin-3 KO: 34.8±3 vs Caveolin-3 KO+DEA-NO:33.7±5), or in the expression of MMPs, suggesting that stabilization of the complex Caveolin-3/LG-EMMPRIN may play a significant role in the cardioprotective effect of NO against IR. PMID:27649573

Nitric Oxide Induces Cardiac Protection by Preventing Extracellular Matrix Degradation through the Complex Caveolin-3/EMMPRIN in Cardiac Myocytes.

PubMed

Cuadrado, Irene; Castejon, Borja; Martin, Ana M; Saura, Marta; Reventun-Torralba, Paula; Zamorano, Jose Luis; Zaragoza, Carlos

2016-01-01

Inhibition of Extracellular Matrix degradation by nitric oxide (NO) induces cardiac protection against coronary ischemia/reperfusion (IR). Glycosylation of Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) stimulates enzymatic activation of matrix metalloproteinases (MMPs) in the heart, although the mechanisms leading to EMMPRIN glycosylation are poorly understood. We sought to determine if NO may induce cardiac protection by preventing glycosylation of EMMPRIN in a mouse model of IR. Here we found that Caveolin-3 binds to low glycosylated EMMPRIN (LG-EMMPRIN) in cardiac cells and in the hearts of healthy mice, whereas IR disrupted the complex in nitric oxide synthase 2 (NOS2) knockout (KO) mice. By contrast, the binding was partially restored when mice were fed with an NO donor (DEA-NO) in the drinking water, showing a significant reduction on infarct size (NOS2KO: 34.6±5 vs NOS2KO+DEA-NO: 20.7±9), in expression of matrix metalloproteinases, and cardiac performance was improved (left ventricular ejection fraction (LVEF). NOS2KO: 31±4 vs NOS2KO+DEA-NO: 46±6). The role of Caveolin-3/EMMPRIN in NO-mediated cardiac protection was further assayed in Caveolin-3 KO mice, showing no significant improvement on infarct size (Caveolin-3 KO: 34.8±3 vs Caveolin-3 KO+DEA-NO:33.7±5), or in the expression of MMPs, suggesting that stabilization of the complex Caveolin-3/LG-EMMPRIN may play a significant role in the cardioprotective effect of NO against IR.

Effects of in ovo exposure to 2,3,7,8-TCDD on F1 generation adult chickens (Gallus gallus).

PubMed

Alonso, K R; Peden-Adams, M M; Liu, J Y; Charbonneau, C; Henshel, D; Dickerson, R L

1998-01-01

White Leghorn chickens (Gallus gallus) were used as surrogate species for the resident wild turkeys found on the Times Beach, Missouri, Superfund site. Parental chickens were injected with concentrations of 2,3,7,8-TCDD which modeled soil concentrations before (200 ppb) and after remediation (1ppb)[1]. Offspring were followed through development to assess alterations in reproductive maturity through the use of a four-way breeding study. F1 adult females exposed to a maternal dose of 8.6 ng/day began egg production approximately two weeks later than did F1 control adult females. By week eight, however, egg production between groups was equivalent. No differences were observed in eggshell gland estrogen or progesterone receptor levels.

THE COMPARISON OF TWO VITRO PALATAL ORGAN CULTURE MODELS TO STUDY CELL SIGNALING PATHWAYS DURING PALATOGENESIS

EPA Science Inventory

This study was performed to determine the best palatal organ culture model to use in evaluating the role of epidermal growth factor (EGF) signaling in the response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Previous work has shown that TCDD and EGF can induce teratogenic effe...

Corticosterone stress response in tree swallows nesting near polychlorinated biphenyl- and dioxin-contaminated rivers

USGS Publications Warehouse

Franceschini, M.D.; Custer, Christine M.; Custer, T.W.; Reed, J.M.; Romero, L.M.

2008-01-01

We assayed baseline and stress-induced corticosterone concentrations from adult female and nestling tree swallows, Tachycineta bicolor, from New England, USA, sites with different levels of contamination with polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Corticosterone was compared over 2 years from a highly contaminated PCB site along the Housatonic River (Berkshire County, MA, USA), a midrange contaminated site upstream, and a reference site. Adult females (n = 29), sampled only in 2003, showed an inverted-U association with PCBs, with higher stress-induced corticosterone with midrange contamination than at the high-contamination site. In nestlings, stress-induced corticosterone was highest for the highly contaminated site compared with the other sites in 2003 (n = 53, 29 nests), with no difference among sites in 2004 (n = 93, 27 nests). In 2004, we began testing mechanisms underlying these changes in nestlings at the high- and low-PCB sites. Corticosterone response to dexamethasone injection (used to test negative feedback) was not different between sites, but stress-induced corticosterone was reduced at the contaminated site after adrenocorticotropin hormone injection (used to test adrenal responsiveness), suggesting an inhibited ability to mount a stress response. We also compared nestlings from a stretch of the Woonasquatucket River, Rhode Island, USA, heavily contaminated with TCDD (n = 80, 43 nests) with nestlings from an upstream site that had lower levels of TCDD and the Berkshire County reference site. Although there were no stress-induced differences, baseline corticosterone was lower at the higher TCDD site than at the reference site. Altogether these findings suggest that tree swallows chronically exposed to high PCB and TCDD levels exhibit altered baseline and stress-induced corticosterone responses, but the patterns of alteration might not be predictable. ?? 2008 SETAC.

High-Fat, High-Sugar Diet-Induced Subendothelial Matrix Stiffening is Mitigated by Exercise.

PubMed

Kohn, Julie C; Azar, Julian; Seta, Francesca; Reinhart-King, Cynthia A

2018-03-01

Consumption of a high-fat, high-sugar diet and sedentary lifestyle are correlated with bulk arterial stiffening. While measurements of bulk arterial stiffening are used to assess cardiovascular health clinically, they cannot account for changes to the tissue occurring on the cellular scale. The compliance of the subendothelial matrix in the intima mediates vascular permeability, an initiating step in atherosclerosis. High-fat, high-sugar diet consumption and a sedentary lifestyle both cause micro-scale subendothelial matrix stiffening, but the impact of these factors in concert remains unknown. In this study, mice on a high-fat, high-sugar diet were treated with aerobic exercise or returned to a normal diet. We measured bulk arterial stiffness through pulse wave velocity and subendothelial matrix stiffness ex vivo through atomic force microscopy. Our data indicate that while diet reversal mitigates high-fat, high-sugar diet-induced macro- and micro-scale stiffening, exercise only significantly decreases micro-scale stiffness and not macro-scale stiffness, during the time-scale studied. These data underscore the need for both healthy diet and exercise to maintain vascular health. These data also indicate that exercise may serve as a key lifestyle modification to partially reverse the deleterious impacts of high-fat, high-sugar diet consumption, even while macro-scale stiffness indicators do not change.

Osteochondral lesions of the ankle joint in professional soccer players: treatment with autologous matrix-induced chondrogenesis.

PubMed

Valderrabano, Victor; Barg, Alexej; Alattar, Abdulhameed; Wiewiorski, Martin

2014-12-01

Acute and recurrent ankle sprains and other trauma to the ankle joint are common injuries in soccer and can be accompanied by or result in osteochondral lesions of the ankle joint, majorly of the talus. Conservative treatment frequently fails. Several operative treatment techniques exist; however, the choice of the right procedure is difficult due to lack of literature with a high level of evidence. We present our treatment method for acute and chronic ankle osteochondral lesions with cystic formation approached by a new surgical technique combining bone plasty and a collagen matrix (autologous matrix-induced chondrogenesis). Therapeutic, Level IV: Case series. © 2014 The Author(s).

A COMPARISON OF THE METABOLISM OF METHOXYRESORUFIN, ACETANILIDE AND CAFFIENE IN RAT AND HUMAN CYP1A2 SUPERSOMES AND THEIR INHIBITION BY 2, 3, 7, 8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

EPA Science Inventory

A COMPARISON OF THE METABOLISM OF METHOXYRESORUFIN, ACETANILIDE AND CAFFIENE IN RAT AND HUMAN CYP1A2 SUPERSOMES AND THEIR INHIBITION BY 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD). DF Staskal1, DG Ross2, LS Birnbaum2 and MJ DeVito2 1Curriculum In Toxicology, UNC-CH, Chapel Hill ...

Predominant Role of Cytosolic Phospholipase A2α in Dioxin-induced Neonatal Hydronephrosis in Mice

PubMed Central

Yoshioka, Wataru; Kawaguchi, Tatsuya; Fujisawa, Nozomi; Aida-Yasuoka, Keiko; Shimizu, Takao; Matsumura, Fumio; Tohyama, Chiharu

2014-01-01

Hydronephrosis is a common disease characterized by dilation of the renal pelvis and calices, resulting in loss of kidney function in the most severe cases. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces nonobstructive hydronephrosis in mouse neonates through upregulation of prostaglandin E2 (PGE2) synthesis pathway consisting of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) by a yet unknown mechanism. We here studied possible involvement of cytosolic phospholipase A2α (cPLA2α) in this mechanism. To this end, we used a cPLA2α-null mouse model and found that cPLA2α has a significant role in the upregulation of the PGE2 synthesis pathway through a noncanonical pathway of aryl hydrocarbon receptor. This study is the first to demonstrate the predominant role of cPLA2α in hydronephrosis. Elucidation of the pathway leading to the onset of hydronephrosis using the TCDD-exposed mouse model will deepen our understanding of the molecular basis of nonobstructive hydronephrosis in humans. PMID:24509627

The direction of stretch-induced cell and stress fiber orientation depends on collagen matrix stress.

PubMed

Tondon, Abhishek; Kaunas, Roland

2014-01-01

Cell structure depends on both matrix strain and stiffness, but their interactive effects are poorly understood. We investigated the interactive roles of matrix properties and stretching patterns on cell structure by uniaxially stretching U2OS cells expressing GFP-actin on silicone rubber sheets supporting either a surface-adsorbed coating or thick hydrogel of type-I collagen. Cells and their actin stress fibers oriented perpendicular to the direction of cyclic stretch on collagen-coated sheets, but oriented parallel to the stretch direction on collagen gels. There was significant alignment parallel to the direction of a steady increase in stretch for cells on collagen gels, while cells on collagen-coated sheets did not align in any direction. The extent of alignment was dependent on both strain rate and duration. Stretch-induced alignment on collagen gels was blocked by the myosin light-chain kinase inhibitor ML7, but not by the Rho-kinase inhibitor Y27632. We propose that active orientation of the actin cytoskeleton perpendicular and parallel to direction of stretch on stiff and soft substrates, respectively, are responses that tend to maintain intracellular tension at an optimal level. Further, our results indicate that cells can align along directions of matrix stress without collagen fibril alignment, indicating that matrix stress can directly regulate cell morphology.

The Methoxyflavonoid Isosakuranetin Suppresses UV-B-Induced Matrix Metalloproteinase-1 Expression and Collagen Degradation Relevant for Skin Photoaging.

PubMed

Jung, Hana; Lee, Eunjoo H; Lee, Tae Hoon; Cho, Man-Ho

2016-09-01

Solar ultraviolet (UV) radiation is a main extrinsic factor for skin aging. Chronic exposure of the skin to UV radiation causes the induction of matrix metalloproteinases (MMPs), such as MMP-1, and consequently results in alterations of the extracellular matrix (ECM) and skin photoaging. Flavonoids are considered as potent anti-photoaging agents due to their UV-absorbing and antioxidant properties and inhibitory activity against UV-mediated MMP induction. To identify anti-photoaging agents, in the present study we examined the preventative effect of methoxyflavonoids, such as sakuranetin, isosakuranetin, homoeriodictyol, genkwanin, chrysoeriol and syringetin, on UV-B-induced skin photo-damage. Of the examined methoxyflavonoids, pretreatment with isosakuranetin strongly suppressed the UV-B-mediated induction of MMP-1 in human keratinocytes in a concentration-dependent manner. Isosakuranetin inhibited UV-B-induced phosphorylation of mitogen-activated protein kinase (MAPK) signaling components, ERK1/2, JNK1/2 and p38 proteins. This result suggests that the ERK1/2 kinase pathways likely contribute to the inhibitory effects of isosakuranetin on UV-induced MMP-1 production in human keratinocytes. Isosakuranetin also prevented UV-B-induced degradation of type-1 collagen in human dermal fibroblast cells. Taken together, our findings suggest that isosakuranetin has the potential for development as a protective agent for skin photoaging through the inhibition of UV-induced MMP-1 production and collagen degradation.

Dioxin-induced retardation of development through a reduction in the expression of pituitary hormones and possible involvement of an aryl hydrocarbon receptor in this defect: A comparative study using two strains of mice with different sensitivities to dioxin

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

Takeda, Tomoki; Taura, Junki; Hattori, Yukiko

We have previously revealed that treating pregnant rats with 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) reduces the expression of gonadotropins and growth hormone (GH) in the fetal and neonatal pituitary. A change in gonadotropin expression impairs the testicular expression of steroidogenic proteins in perinatal pups, and imprint defects in sexual behavior after reaching maturity. In this study, we examined whether TCDD also affects the expression of gonadotropin and GH in mice using C57BL/6J and DBA/2J strains which express the aryl hydrocarbon receptor (Ahr) exhibiting a different affinity for TCDD. When pregnant C57BL/6J mice at gestational day (GD) 12 were given oral TCDD (0.2–20 μg/kg),more » all doses significantly attenuated the pituitary expression of gonadotropin mRNAs in fetuses at GD18. On the other hand, in DBA/2J mice, a much higher dose of TCDD (20 μg/kg) was needed to produce a significant attenuation. Such reduction in the C57BL/6J strain continued until at least postnatal day (PND) 4. In agreement with this, TCDD reduced the testicular expression of steroidogenic proteins in C57BL/6J neonates at PND2 and 4, although the same did not occur in the fetal testis and ovary. Furthermore, TCDD reduced the perinatal expression of GH, litter size and the body weight of newborn pups only in the C57BL/6J strain. These results suggest that 1) also in mice, maternal exposure to TCDD attenuates gonadotropin-regulated steroidogenesis and GH expression leading to the impairment of pup development and sexual immaturity; and 2) Ahr activation during the late fetal and early postnatal stages is required for these defects. - Highlights: • The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on mouse growth was studied. • TCDD reduced the levels of luteinizing hormone and growth hormone in perinatal pups. • Maternal exposure to TCDD also attenuated testicular steroidogenesis in pups. • The above effects of TCDD were more pronounced in C57BL/6J than

Tangeretin inhibits high glucose-induced extracellular matrix accumulation in human glomerular mesangial cells.

PubMed

Chen, Fang; Ma, Yali; Sun, Zhiqiang; Zhu, Xiaoguang

2018-06-01

Tangeretin (5, 6, 7, 8, 4'-pentamethoxyflavone), a natural compound extracted from citrus plants, has been shown to possess a variety of pharmacological activities, including anti-oxidant, anti-tumor, cytostatic and anti-diabetic properties. However, the role of tangeretin in diabetic nephropathy (DN) has not yet been investigated. This study was undertaken to elucidate the effects of tangeretin on high glucose (HG)-induced oxidative stress and extracellular matrix (ECM) accumulation in human glomerular mesangial cells (MCs) and explore the underlying mechanisms. Our results showed that tangeretin significantly inhibited HG-induced the proliferation of MCs. In addition, tangeretin dramatically reduced the levels of reactive oxygen species (ROS) and malondialdhyde (MDA), and induced SOD activity, as well as inhibited the expression of fibronectin (FN) and collagen IV in HG-stimulated MCs. Furthermore, tangeretin efficiently prevented the activation of ERK signaling pathway in HG-stimulated MCs. Taken together, these data indicated that tangeretin inhibits HG-induced cell proliferation, oxidative stress and ECM expression in glomerular MCs, at least in part, through the inactivation of ERK signaling pathway. Therefore, tangeretin may be a potential agent in the treatment of DN. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Association of matrix metalloproteinase inducer (EMMPRIN) with the expression of matrix metalloproteinases-1, -2 and -9 during periapical lesion development.

PubMed

Sousa, Natália Guimarães Kalatzis; Cardoso, Cristina Ribeiro de Barros; Silva, João Satana da; Kuga, Milton Carlos; Tanomaru-Filho, Mário; Faria, Gisele

2014-09-01

To evaluate the expression of matrix metalloproteinase inducer (EMMPRIN) and its correlation with the expression of matrix metalloproteinases (MMPs)-1, -2 and -9 during the development of periapical lesion in mice. Periapical lesions were induced in the lower first molars of mice and after 7, 14, 21 and 42 days the mandibles were removed. The periapical lesions were measured by micro-computed tomography. The expression of EMMPRIN, MMPs-1, -2, and -9 genes were determined by real-time RT-PCR. The location and expression of EMMPRIN and MMPs were evaluated by immunohistochemistry. At 14 days, the periapical lesion area was higher than at 7 days. At 21 and 42 days no statistically significant bone loss was observed in comparison to 14 days. The control group showed discrete and occasional EMMPRIM, MMP-1, -2 and -9 immunostaining in the periodontal ligament fibroblasts. At 7, 14, 21 and 42 days intense immunoexpression was observed for EMMPRIN, MMPs-1, -2 and -9 in the region adjacent to the apical foramen. The EMMPRIN immunoexpression was higher at 7, 14, 21 and 42 days compared with the control. There was a positive correlation between gene expression of EMMPRIN and MMPs in the active phase of periapical lesion development. There is a high expression of EMMPRIM mainly by the inflammatory infiltrate in the region adjacent to the apical foramen during periapical lesion development. Furthermore, the positive correlation with MMP-1, -2, and -9 during the first days after periapical lesion induction indicates that EMMPRIM may be involved in the active phase of periapical lesions development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Regulation of Bach2 by the aryl hydrocarbon receptor as a mechanism for suppression of B-cell differentiation by 2,3,7,8-tetrachlorodibenzo-p-dioxin

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

De Abrew, K. Nadira; Phadnis, Ashwini S.; Genetics Program, Michigan State University, East Lansing, MI 48824

2011-04-15

Exposure to the aryl hydrocarbon receptor (AHR) agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters B-cell differentiation and suppresses antibody production. Previous genomic studies in mouse B cells identified Bach2 as a direct target of the AHR. Bach2 is known to repress expression of Prdm1, a key transcription factor involved in B-cell differentiation, by binding to Maf elements (MAREs) in the regulatory regions of the gene. Chromatin immunoprecipitation followed by quantitative PCR in TCDD-treated lipopolysaccharide (LPS)-activated B cells showed increased binding of the AHR within the first intron in the Bach2 gene. The binding was further confirmed by electrophoretic mobility shift assay (EMSA). TCDDmore » also induced expression of Bach2 in activated as well as resting B cells from 2 to 24 h post-treatment in a time- and concentration-dependent manner. Expression of Prdm1 was decreased by TCDD at 24 h and was consistent with repression by Bach2. Increased DNA binding activity to the intron 5 MARE with increasing TCDD concentrations was observed by EMSA. Supershifts identified the presence of Bach2 in the DNA binding complex associated with the intron 5 MARE of Prdm1. Functional validation of the role of Bach2 in the suppression of B-cell differentiation by TCDD was performed using RNA interference (RNAi). Knockdown of Bach2 showed approximately 40% reversal in the TCDD-induced suppression of IgM secretion when compared to controls. The results suggest that the transcriptional regulation of Bach2 by the AHR is one of the mechanisms involved in the suppression of B-cell differentiation by TCDD.« less

Attenuation of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity by resveratrol: a comparative study with different routes of administration.

PubMed

Ishida, Takumi; Takeda, Tomoki; Koga, Takayuki; Yahata, Masahiro; Ike, Ayako; Kuramoto, Chihiro; Taketoh, Junko; Hashiguchi, Isamu; Akamine, Akifumi; Ishii, Yuji; Yamada, Hideyuki

2009-05-01

The activation of aryl hydrocarbon receptor with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is known to be antagonized by co-treatment with resveratrol. However, such a protective effect has been suggested from studies using subcutaneous injection of this polyphenol. To evaluate the practical usefulness of resveratrol, this study examined the protective effect of oral resveratrol on the sub-acute toxic effects of TCDD in C57BL/6J mice. A TCDD-induced wasting syndrome was not alleviated by treating mice for 28 d with oral resveratrol. However, subcutaneous injection of resveratrol for 5 d significantly improved the symptoms. Neither oral nor subcutaneous administration of resveratrol alleviated TCDD-induced hepatomegaly and thymic atrophy. Steatosis produced by TCDD was markedly counteracted by co-treatment with oral resveratrol, whereas resveratrol injected subcutaneously had no effect. The reason for the lack of protective effect via the latter dosing route was assumed to be due to the minor accumulation of hepatic lipids 5 d after TCDD treatment. To clarify the mechanisms, the activity of ethoxyresorufin O-deethylase and the content of thiobarbituric acid-reactive substances in the liver were measured. Both indices increased by TCDD treatment were significantly suppressed by subcutaneous injection of resveratrol. In contrast, oral resveratrol failed to rescue them. In agreement with the greater protective effects of subcutaneously-injected resveratrol, pharmacokinetic studies indicated that the area under the curve extrapolated to infinity (AUC(infinity)) was 8.2-times greater following subcutaneous injection compared with oral administration. These data suggest that 1) oral resveratrol is attractive candidate as an agent capable of combating dioxin toxicity and 2) increasing the bioavailability of this polyphenol enhances its protective effect.

Periodic Mechanical Stress INDUCES Chondrocyte Proliferation and Matrix Synthesis via CaMKII-Mediated Pyk2 Signaling.

PubMed

Liang, Wenwei; Li, Zeng; Wang, Zhen; Zhou, Jinchun; Song, Huanghe; Xu, Shun; Cui, Weiding; Wang, Qing; Chen, Zhefeng; Liu, Feng; Fan, Weimin

2017-01-01

Periodic mechanical stress can promote chondrocyte proliferation and matrix synthesis to improve the quality of tissue-engineered cartilage. Although the integrin β1-ERK1/2 signal cascade has been implicated in periodic mechanical stress-induced mitogenic effects in chondrocytes, the precise mechanisms have not been fully established. The current study was designed to probe the roles of CaMKII and Pyk2 signaling in periodic mechanical stress-mediated chondrocyte proliferation and matrix synthesis. Chondrocytes were subjected to periodic mechanical stress, proliferation was assessed by direct cell counting and CCK-8 assay; gene expressions were analyzed using quantitative real-time PCR, protein abundance by Western blotting. Mechanical stress, markedly enhanced the phosphorylation levels of Pyk2 at Tyr402 and CaMKII at Thr286. Both suppression of Pyk2 with Pyk2 inhibitor PF431396 or Pyk2 shRNA and suppression of CaMKII with CaMKII inhibitor KN-93 or CaMKII shRNA blocked periodic mechanical stress-induced chondrocyte proliferation and matrix synthesis. Additionally, either pretreatment with KN-93 or shRNA targeted to CaMKII prevented the activation of ERK1/2 and Pyk2 under conditions of periodic mechanical stress. Interestingly, in relation to periodic mechanical stress, in the context of Pyk2 inhibition with PF431396 or its targeted shRNA, only the phosphorylation levels of ERK1/2 were abrogated, while CaMKII signal activation was not affected. Moreover, the phosphorylation levels of CaMKII- Thr286 and Pyk2- Tyr402 were abolished after pretreatment with blocking antibody against integrinβ1 exposed to periodic mechanical stress. Our results collectively indicate that periodic mechanical stress promotes chondrocyte proliferation and matrix synthesis through the integrinβ1-CaMKII-Pyk2-ERK1/2 signaling cascade. © 2017 The Author(s). Published by S. Karger AG, Basel.

On the thermally-induced residual stresses in thick fiber-thermoplastic matrix (PEEK) cross-ply laminated plates

NASA Technical Reports Server (NTRS)

Hu, Shoufeng; Nairn, John A.

1992-01-01

An analytical method for calculating thermally-induced residual stresses in laminated plates is applied to cross-ply PEEK laminates. We considered three cooling procedures: slow cooling (uniform temperature distribution); convective and radiative cooling; and rapid cooling by quenching (constant surface temperature). Some of the calculated stresses are of sufficient magnitude to effect failure properties such as matrix microcracking.

Involvement of SREBPs in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced disruption of lipid metabolism in male guinea pig

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

Nishiumi, Shin; Yabushita, Yoshiyuki; Furuyashiki, Takashi

2008-06-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has multiple toxic effects causing a wasting syndrome characterized by a loss of body weight accompanied by a decrease in adipose tissue weight. To elucidate the mechanism behind this syndrome, we investigated the changes in lipid metabolism 7 and 21 days after a single intraperitoneal injection of TCDD at 1 {mu}g/kg body weight to male guinea pigs. TCDD caused the symptoms of the syndrome, body weight loss with a decrease in adipose tissue weight, while it increased the levels of triacylglycerols, total cholesterols, and free fatty acids in plasma. On day 7, TCDD decreased the levels of CCAAT/enhancermore » binding protein (C/EBP) {alpha}, peroxisome proliferator activated receptor {gamma}, and glucose transporter 4, adipogenesis-related factors, in adipose tissue, whereas the levels of retinoid X receptor {alpha}, C/EBP{beta}, C/EBP{delta}, and c-Myc remained unchanged. TCDD also reduced the levels of both p125 precursor and p68 active forms of sterol regulatory element binding protein (SREBP)-1 and -2, the lypogenesis-related factors, and downregulated their DNA binding activity in adipose tissue, while it raised the levels of their p68 active forms and increased their DNA binding activity in the liver. TCDD decreased mRNA and protein levels of acetyl-CoA carboxylase and HMG-CoA synthase in the liver and adipose tissue. Similar results were obtained on day 21. These results suggest that TCDD disrupts lipid metabolism through changes in the expression levels of the adipogenesis-related and lipogenesis-related proteins in the liver and adipose tissue, and SREBPs would be involved in the development of the wasting syndrome.« less

Downregulated Smad4 Affects Extracellular Matrix Remodeling in Ventilator-induced Lung Injury.

PubMed

Huang, Xiaofang; Zhou, Wei; Ding, Shifang

2016-09-01

To explore the effect of Smad4 on the extracellular matrix remodeling in ventilator-induced lung injury (VILI). We randomized 24 C57BL/6 mice to 4 groups for treatment (n=6/group): control, ventilation, non-targeted (scramble) lentivirus transfection plus ventilation, and Smad4 small interfering RNA (siRNA) lentivirus transfection plus ventilation. Lentivirus was delivered by intranasal instillation. Four weeks later, the 3 ventilated groups underwent high tidal volume (VT 40mL/kg) ventilation to induce lung injury. After 72 hours, lungs were collected from the anesthetized live mice. Histological changes in lungs were evaluated by hematoxylin and eosin and Masson's staining. The expression of α-smooth muscle actin (α-SMA) was determined by immunohistochemistry, and the mRNA and protein levels of Smad4, α-SMA, and collagen I and III were detected by quantitative real-time PCR and western blotting analysis. Smad4 siRNAs significantly knocked down Smad4 expression (P<.05), which was increased with ventilation, thereby alleviating inflammatory cell infiltration. It also inhibited accumulation of α-SMA-positive myofibroblasts and pulmonary fibrosis, as seen by reduced collagen I and III expression (P<.05), induced by ventilation. Scramble siRNA treatment had no effect (P>.05). Smad4 gene silencing may be a therapeutic target for treating ventilator-induced lung injury and pulmonary fibrosis. © 2016 by the Association of Clinical Scientists, Inc.

The aryl hydrocarbon receptor is indispensable for dioxin-induced defects in sexually-dimorphic behaviors due to the reduction in fetal steroidogenesis of the pituitary-gonadal axis in rats.

PubMed

Hattori, Yukiko; Takeda, Tomoki; Nakamura, Arisa; Nishida, Kyoko; Shioji, Yuko; Fukumitsu, Haruki; Yamada, Hideyuki; Ishii, Yuji

2018-05-16

Many forms of the toxic effects produced by dioxins and related chemicals take place following activation of the aryl hydrocarbon receptor (AHR). Our previous studies have demonstrated that treating pregnant rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic dioxin, attenuates the pituitary expression of gonadotropins to reduce testicular steroidogenesis during the fetal stage, resulting in the impairment of sexually-dimorphic behaviors after the offspring reach maturity. To investigate the contribution of AHR to these disorders, we examined the effects of TCDD on AHR-knockout (AHR-KO) Wistar rats. When pregnant AHR-heterozygous rats were given an oral dose of 1 µg/kg TCDD at gestational day (GD) 15, TCDD reduced the expression of pituitary gonadotropins and testicular steroidogenic proteins in male wild-type fetuses at GD20 without affecting body weight, sex ratio and litter size. However, the same defect did not occur in AHR-KO fetuses. Further, fetal exposure to TCDD impaired the activity of masculine sexual behavior after reaching adulthood only in the wild-type offspring. Also, in female offspring, not only the fetal gonadotropins production but also sexual dimorphism, such as saccharin preference, after growing up were suppressed by TCDD only in the wild-type. Interestingly, in the absence of TCDD, deleting AHR reduced masculine sexual behavior, as well as fetal steroidogenesis of the pituitary-gonadal axis. These results provide novel evidence that 1) AHR is required for TCDD-produced defects in sexually-dimorphic behaviors of the offspring, and 2) AHR signaling plays a role in gonadotropin synthesis during the developmental stage to acquire sexual dimorphism after reaching adulthood. Copyright © 2018 Elsevier Inc. All rights reserved.

Enhanced endothelial cell senescence by lithium-induced matrix metalloproteinase-1 expression.

PubMed

Struewing, Ian T; Durham, Samuel N; Barnett, Corey D; Mao, Catherine D

2009-06-26

Endothelial cell (EC) senescence and dysfunction occurring after chronic injury and inflammation are highly associated with the development and progression of cardiovascular diseases. However, the factors involved in the establishment of EC senescence remain poorly understood. We have previously shown that lithium, an inhibitor of glycogen synthase kinase (GSK)-3beta and activator of the Wnt/beta-catenin signaling pathway, induces an EC senescent-like phenotype. Herein, we show that lithium induces a rapid and pronounced up-regulation of the matrix metalloproteinase (MMP)-1, an inflammation and senescent cell marker, at the mRNA and protein levels, whereas the induction of two other senescent cell markers is either weak (interleukin-8) or delayed (plasminogen activator inhibitor-1). Lithium effect on MMP-1 expression is also specific among other MMPs and not mediated by GSK3beta inhibition. Lithium affects MMP-1 expression mainly at the transcriptional level but neither the AP1/Ets regulatory sites nor the redox sensitive (-1607/2G) site in MMP-1 promoter are involved in lithium-dependent MMP-1 regulation. However, down-regulation of p53, a target of lithium in EC, dampens both basal and lithium-induced MMP-1 expression, which further links MMP-1 up-regulation with the establishment of cell senescence. Although increased MMP-1 levels are usually associated with angiogenesis in enabled proliferative EC, the exogenous addition of activated MMP-1 on lithium- arrested EC increases the number of EC positive for the senescent-associated-beta-galactosidase marker. Conversely, down-regulation of MMP-1 expression by small interfering RNAs blunts the lithium-dependent increase in senescent-associated-beta-galactosidase positive cells. Altogether our data indicate that lithium-induced MMP-1 may participate in the reinforcement of EC senescence and reveal a novel mechanism for lithium-induced tissue remodeling.

Neuropsychotoxicity of abused drugs: involvement of matrix metalloproteinase-2 and -9 and tissue inhibitor of matrix metalloproteinase-2 in methamphetamine-induced behavioral sensitization and reward in rodents.

PubMed

Mizoguchi, Hiroyuki; Yamada, Kiyofumi; Nabeshima, Toshitaka

2008-01-01

Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) function to remodel the pericellular environment. We have investigated the role of the MMP/TIMP system in methamphetamine (METH) dependence in rodents, in which the remodeling of neural circuits may be crucial. Repeated METH treatment induced behavioral sensitization, which was accompanied by an increase in MMP-2/-9/TIMP-2 activity in the brain. An antisense TIMP-2 oligonucleotide enhanced the sensitization, which was associated with a potentiation of the METH-induced release of dopamine in the nucleus accumbens (NAc). MMP-2/-9 inhibitors blocked the METH-induced behavioral sensitization and conditioned place preference (CPP), a measure of the rewarding effect of a drug, and reduced the METH-increased dopamine release in the NAc. In MMP-2- and MMP-9-deficient mice, METH-induced behavioral sensitization and CPP as well as dopamine release were attenuated. The MMP/TIMP system may be involved in METH-induced sensitization and reward by regulating extracellular dopamine levels.

A potential endogenous ligand for the aryl hydrocarbon receptor has potent agonist activity in vitro and in vivo.

PubMed

Henry, E C; Bemis, J C; Henry, O; Kende, A S; Gasiewicz, T A

2006-06-01

The aryl hydrocarbon receptor (AhR) is best known as a mediator of toxicity of a diverse family of xenobiotic chemicals such as dioxins and PCBs. However, many naturally occurring compounds also activate AhR. One such compound, 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), was isolated from tissue and found to be potent in preliminary tests [J. Song, M. Clagett-Dame, R.E. Peterson, M.E. Hahn, W.M. Westler, R.R. Sicinski, H.F. DeLuca, Proc. Natl. Acad. Sci. USA 99 (2002) 14694-14699]. We have synthesized ITE and [(3)H]ITE and further evaluated its AhR activity in several in vitro and in vivo assays in comparison with the toxic ligand, TCDD. AhR in Hepa1c1c7 cell cytosol bound [(3)H]ITE with high affinity and the AhR.ITE complex formed in vitro bound dioxin response element (DRE) oligonucleotide as potently as TCDD.AhR. In cells treated with ITE, nuclear translocation of AhR, and induction of CYP1A1 protein and of a DRE-dependent luciferase reporter gene were observed. ITE administered to pregnant DRE-LacZ transgenic mice activated fetal AhR, observed as X-gal staining in the same sites as in TCDD-treated mice. However, unlike TCDD, ITE did not induce cleft palate or hydronephrosis. TCDD but not ITE induced thymic atrophy in young adult mice, but both ITE and TCDD caused similar loss of cells and alterations of cell profiles in cultured fetal thymi. These data demonstrate that ITE is a potent AhR agonist in cell extracts, cultured cells, and intact animals, but does not cause the toxicity associated with the more stable xenobiotic ligand, TCDD.

2,3,7,8-Tetrachlorodibenzo-p-dioxin activates the aryl hydrocarbon receptor and alters sex steroid hormone secretion without affecting growth of mouse antral follicles in vitro

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

Karman, Bethany N., E-mail: bklement@illinois.edu; Basavarajappa, Mallikarjuna S., E-mail: mbshivapur@gmail.com; Craig, Zelieann R., E-mail: zelieann@illinois.edu

The persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an ovarian toxicant. These studies were designed to characterize the actions of TCDD on steroidogenesis and growth of intact mouse antral follicles in vitro. Specifically, these studies tested the hypothesis that TCDD exposure leads to decreased sex hormone production/secretion by antral follicles as well as decreased growth of antral follicles in vitro. Since TCDD acts through binding to the aryl hydrocarbon receptor (AHR), and the AHR has been identified as an important factor in ovarian function, we also conducted experiments to confirm the presence and activation of the AHR in our tissue culturemore » system. To do so, we exposed mouse antral follicles for 96 h to a series of TCDD doses previously shown to have effects on ovarian tissues and cells in culture, which also encompass environmentally relevant and pharmacological exposures (0.1–100 nM), to determine a dose response for TCDD in our culture system for growth, hormone production, and expression of the Ahr and Cyp1b1. The results indicate that TCDD decreases progesterone, androstenedione, testosterone, and estradiol levels in a non-monotonic dose response manner without altering growth of antral follicles. The addition of pregnenolone substrate (10 μM) restores hormone levels to control levels. Additionally, Cyp1b1 levels were increased by 3–4 fold regardless of the dose of TCDD exposure, evidence of AHR activation. Overall, these data indicate that TCDD may act prior to pregnenolone formation and through AHR transcriptional control of Cyp1b1, leading to decreased hormone levels without affecting growth of antral follicles. -- Highlights: ►TCDD disrupts sex steroid hormone levels, but not growth of antral follicles. ►Pregnenolone co-treatment by-passes TCDD-induced steroid hormone disruption. ►TCDD affects steroid hormone levels through an AHR pathway in antral follicles.« less

Effects of embryonic and adult exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin on hepatic microsomal testosterone hydroxylase activities in great blue herons (Ardea herodias)

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

Sanderson, J.T.; Giesy, J.P.; Janz, D.M.

In a continuing effort to evaluate biomarkers of exposure of great blue herons (Ardea herodias) to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related halogenated aromatic hydrocarbons, the authors examined the effect of TCDD on hepatic microsomal testosterone hydroxylase activities. Heron embryos were exposed in ovo to 2 {micro}g TCDD/kg egg (or corn oil vehicle) and sacrificed at hatch or 7 d posthatch. Adult herons were exposed intraperitoneally to 20 {micro}g TCDD/kg and sacrificed 2 weeks later. The sex of the birds was known for the adults only. Hepatic microsomes of herons of each age group were able to hydroxylate testosterone at the 2{beta},more » 6{beta}, 15{alpha}, 16{alpha}, or 16{beta} positions. In 7-d-old chicks, an additional unidentified compound was formed. The age of the untreated herons had a strong influence on the activities of the five hydroxylases, with changes of up to 17-fold. The TCDD significantly induced 2{beta}-, 6{beta}, and 15{alpha}-testosterone hydroxylase activities in the adult females, 15{alpha} in the adult males, and 6{beta}-testosterone hydroxylase activity in the hatchlings. In the 7-d-old chicks, induction was no longer apparent. A significant correlation existed between hepatic microsomal ethoxyresorufin O-deethylase (EROD) and 6{beta}-testosterone hydroxylase activity in hatchlings and adult female herons. The TCDD-induced changes in testosterone hydroxylase activities occurred at doses that resulted in tissue concentrations and levels of EROD induction that were environmentally relevant, but did not result in overt toxicities.« less

Relationships among cytochromes P450 and dioxin equivalents in pipping heron embryos from Virginia, the Great Lakes and San Francisco Bay

USGS Publications Warehouse

Rattner, B.A.; Hatfield, J.S.; Melancon, M.J.; Custer, T.W.; Tillett, D.E.

1993-01-01

Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from undisturbed (Chincoteague National Wildlife Refuge, VA) and industrialized (Cat Island, Green Bay, WI; San Francisco Bay, CA) locations. Hepatic P450 associated monooxygenases (AHH, EROD, BROD, ECOD) and P450 proteins (CYP1A, CYP2B) were induced up to 85-fold, and were associated with burdens of total PCBs and 11 AHH-active PCB congeners. Dioxin equivalents (TCDD-EQs) of sample extracts, derived by bioassay (H4I1E rat hepatoma cell) and mathematically (product of PCB congener concentration and relative TCDD potency), revealed greatest TCDD-EQs in Cat Island samples. TCDD-EQs were associated with P450s, especially BROD, EROD and CYP1A (r2 = 0.35 to 0.66). TCDD-EQs derived by bioassay were highly correlated with TCDD-EQs derived mathematically (r2 = 0.58 to 0.67) . Multiple regressions were also performed to investigate relationships among P450s and PCB congeners. In summary, these data demonstrate that hepatic P450s of heron embryos are biomarkers of exposure to dioxin-like compounds and provide further evidence that this species has considerable value for assessing wetland and estuarine contamination.

INFLUENCE OF TYPE II DIABETES, OBESITY, AND EXPOSURE TO 2, 3, 7, 8-TETRACHLORODIBENZO-P-DIOXIN (TCDD) EXPOSURE ON THE EXPRESSION OF HEPATIC CYP1A2 IN A MURIN MODEL OF TYPE II DIABETES

EPA Science Inventory

Influence of type II diabetes, obesity and exposure 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure on the expression of hepatic CYPIA2 in a murine model of type II diabetes. SJ Godin', VM Richardson2, JJ Diliberto2, LS Birnbaum', MJ DeVito2; 'Curriculum In Toxicology, UNC-CH...

Dioxin inhibition of swim bladder development in zebrafish: is it secondary to heart failure?

PubMed

Yue, Monica S; Peterson, Richard E; Heideman, Warren

2015-05-01

The swim bladder is a gas-filled organ that is used for regulating buoyancy and is essential for survival in most teleost species. In zebrafish, swim bladder development begins during embryogenesis and inflation occurs within 5 days post fertilization (dpf). Embryos exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) before 96 h post fertilization (hpf) developed swim bladders normally until the growth/elongation phase, at which point growth was arrested. It is known that TCDD exposure causes heart malformations that lead to heart failure in zebrafish larvae, and that blood circulation is a key factor in normal development of the swim bladder. The adverse effects of TCDD exposure on the heart occur during the same period of time that swim bladder development and growth occurs. Based on this coincident timing, and the dependence of swim bladder development on proper circulatory development, we hypothesized that the adverse effects of TCDD on swim bladder development were secondary to heart failure. We compared swim bladder development in TCDD-exposed embryos to: (1) silent heart morphants, which lack cardiac contractility, and (2) transiently transgenic cmlc2:caAHR-2AtRFP embryos, which mimic TCDD-induced heart failure via heart-specific, constitutive activation of AHR signaling. Both of these treatment groups, which were not exposed to TCDD, developed hypoplastic swim bladders of comparable size and morphology to those found in TCDD-exposed embryos. Furthermore, in all treatment groups swim bladder development was arrested during the growth/elongation phase. Together, these findings support a potential role for heart failure in the inhibition of swim bladder development caused by TCDD. Copyright © 2015 Elsevier B.V. All rights reserved.

Heat- and light-induced transformations of Yb trapping sites in an Ar matrix

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

Tao, L.-G.; Lambo, R., E-mail: lambo@mail.ustc.edu.cn; Zhou, X.-G.

2015-11-07

The low-lying electronic states of Yb isolated in a solid Ar matrix grown at 4.2 K are characterized through absorption and emission spectroscopy. Yb atoms are found to occupy three distinct thermally stable trapping sites labeled “red,” “blue,” and “violet” according to the relative positions of the absorption features they produce. Classical simulations of the site structure and relative stability broadly reproduced the experimentally observed matrix-induced frequency shifts and thus identified the red, blue, and violet sites as due to respective single substitutional (SS), tetravacancy (TV), and hexavacancy (HV) occupation. Prolonged excitation of the {sup 1}S → {sup 1}P transitionmore » was found to transfer the Yb population from HV sites into TV and SS sites. The process showed reversibility in that annealing to 24 K predominantly transferred the TV population back into HV sites. Population kinetics were used to deduce the effective rate parameters for the site transformation processes. Experimental observations indicate that the blue and violet sites lie close in energy, whereas the red one is much less stable. Classical simulations identify the blue site as the most stable one.« less

Prediction of thermal cycling induced matrix cracking

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1992-01-01

Thermal fatigue has been observed to cause matrix cracking in laminated composite materials. A method is presented to predict transverse matrix cracks in composite laminates subjected to cyclic thermal load. Shear lag stress approximations and a simple energy-based fracture criteria are used to predict crack densities as a function of temperature. Prediction of crack densities as a function of thermal cycling is accomplished by assuming that fatigue degrades the material's inherent resistance to cracking. The method is implemented as a computer program. A simple experiment provides data on progressive cracking of a laminate with decreasing temperature. Existing data on thermal fatigue is also used. Correlations of the analytical predictions to the data are very good. A parametric study using the analytical method is presented which provides insight into material behavior under cyclical thermal loads.

Hypertension, Cardiac Hypertrophy, and Impaired Vascular Relaxation Induced by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin are Associated with Increased Superoxide

USDA-ARS?s Scientific Manuscript database

The mechanisms by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) increases the incidence of human cardiovascular disease are not known. We investigated the degree to which cardiovascular disease develops in mice following subchronic TCDD exposure. Adult male C57BL/6 mice were dosed with vehicle o...

USE OF CYP1A2(-/-) KNOCKOUT AND CYP1A2(+/+) C57BL/6N PARENTAL STRAINS OF MICE TO COMPARE METABOLISM OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD)

EPA Science Inventory

USE OF CYP1A2 (-/-) KNOCKOUT AND CYP1A2 (+/+) C57BL/6N PARENTAL STRAINS OF MICE TO COMPARE METABOLISM OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN (TCDD). J J Diliberto1 and H Hakk2. 1USEPA ORD, NHEERL, ETD, PKB, Research Triangle Park, NC, USA; 2USDA-ARS, BRL, Fargo, ND, USA. Spons...

Myc-induced anchorage of the rDNA IGS region to nucleolar matrix modulates growth-stimulated changes in higher-order rDNA architecture

PubMed Central

Shiue, Chiou-Nan; Nematollahi-Mahani, Amir; Wright, Anthony P.H.

2014-01-01

Chromatin domain organization and the compartmentalized distribution of chromosomal regions are essential for packaging of deoxyribonucleic acid (DNA) in the eukaryotic nucleus as well as regulated gene expression. Nucleoli are the most prominent morphological structures of cell nuclei and nucleolar organization is coupled to cell growth. It has been shown that nuclear scaffold/matrix attachment regions often define the base of looped chromosomal domains in vivo and that they are thereby critical for correct chromosome architecture and gene expression. Here, we show regulated organization of mammalian ribosomal ribonucleic acid genes into distinct chromatin loops by tethering to nucleolar matrix via the non-transcribed inter-genic spacer region of the ribosomal DNA (rDNA). The rDNA gene loop structures are induced specifically upon growth stimulation and are dependent on the activity of the c-Myc protein. Matrix-attached rDNA genes are hypomethylated at the promoter and are thus available for transcriptional activation. rDNA genes silenced by methylation are not recruited to the matrix. c-Myc, which has been shown to induce rDNA transcription directly, is physically associated with rDNA gene looping structures and the intergenic spacer sequence in growing cells. Such a role of Myc proteins in gene activation has not been reported previously. PMID:24609384

Expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and its expected roles in the bovine endometrium during gestation.

PubMed

Mishra, B; Kizaki, K; Koshi, K; Ushizawa, K; Takahashi, T; Hosoe, M; Sato, T; Ito, A; Hashizume, K

2012-02-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) and its induced matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling during the peri-implantation period. However, the role of EMMPRIN in the bovine placenta is still unclear. We have postulated that EMMPRIN might play a regulatory role in trophoblastic cell functions during gestation by itself or through the regulation of MMP expression. In this study, EMMPRIN mRNA was detected in the bovine placentome and interplacentome throughout gestation, and its expression was significantly higher in the cotyledon during late gestation. In situ hybridization showed that EMMPRIN mRNA was expressed in the caruncular epithelium and the cotyledonary epithelium, including binucleate cells. Western blot analysis detected a band representing a protein of approximately 65 kDa in the caruncular and cotyledonary tissues, and the intensity of its expression was increased in both of these tissues during late gestation. The expression levels of MMP-2 and MMP-14 in the bovine placenta were higher during late gestation, as was observed for EMMPRIN. Therefore, EMMPRIN might regulate trophoblastic cell functions, especially those of binucleate cells, through MMP expression in the bovine placenta. Copyright © 2012 Elsevier Inc. All rights reserved.

Tumor necrosis factor-α inhibits effects of aryl hydrocarbon receptor ligands on cell death in human lymphocytes.

PubMed

Ghatrehsamani, Mahdi; Soleimani, Masoud; Esfahani, Behjat A Moayedi; Shirzad, Hedayatollah; Hakemi, Mazdak G; Mossahebimohammadi, Majid; Eskandari, Nahid; Adib, Minoo

2015-01-01

Activation of aryl hydrocarbon receptor (AhR) leads to diverse outcome in various kinds of cells. AhR activation may induce apoptosis or prevent of apoptosis and cell death. Recent studies suggest that apoptosis effects of AhR can be modulated by inflammatory cytokine like tumor necrosis factor alpha (TNF-α). In this study, we try to investigate the possible interaction of TNF-α with the 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), a ligand of AhR, on peripheral lymphocytes. Human peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood by discontinuous density gradient centrifugation on ficoll. Isolated PBMCs were divided into four groups: Control group, TNF-α administered group, TCDD administered group, co-administered group with TCDD and TNF-α. Cells were maintained for a week in lymphocyte culture condition. Then, TNF-α was added to group 2 and 4. Finally, apoptosis and necrosis were analyzed in all samples using flowcytometry. In group 4, the mean percent of necrosis and apoptosis in TCDD treatment groups was significantly larger than other groups; (P < 0.05). Furthermore, there was no significant difference between the mean percent of cell death in TNF-α administered group and TCDD administered group (P > 0.05). However, the mean percent of cell death in co-administered group with TCDD and TNF-α was significantly lower than other groups; (P < 0.05). TNF-α could significantly inhibit effects of TCDD on lymphocytes apoptosis. Combination effects of TNF-α and TCDD on lymphocyte increase cell survival.

The use of semipermeable membrane devices (SPMDs) to concentrate inducers of fish hepatic mixed function oxygenase (MFO): Chapter 12

USGS Publications Warehouse

Parrott, Joanne L.; Tillitt, Donald E.

1997-01-01

Semipermeable membrane devices (SPMDs) are sampling and concentrating devices comprised of a thin polyethylene membrane containing a small quantity of triolein. They have previously been used to sample air, water and sediments and have concentrated fish tainting compounds from pulp mill effluents. The ability to induce mixed function oxygenases (MFOs) is a property of a variety of organic effluents, but the compound(s) responsible for induction have not been identified. We wanted to see if SPMDs would accumulate the MFO-inducing chemical(s) from pulp mill effluents and oil refinery effluents. Dialysates of effluent-exposed SPMDs induced ethoxyresorufin-O-deethylase (EROD) activity in a fish (Poeciliopsis lucida) hepatoma cell line, PLHC-1. In pulp mill effluents and oil sands mining and refining wastewaters, potencies varied greatly, from a few to thousands of pg TCDD-EQ/g SPMD. Low levels of inducers were seen in four pulp mills on the Athabasca R., and higher levels at one New Brunswick bleached sulphite and two Ontario bleached kraft pulp mills. The highest levels of MFO inducers were in SPMDs deployed for 14 days in wastewater from an oil sands upgrading facility, as well as SPMDs deployed at two sites on Athabasca River tributaries in the oil sands area. This suggests that natural erosion and weathering, as well as industrial processing of the oil sands, can release potent MFO inducers. Background (reference) induction by SPMD extracts ranged from non-detectable (<1) to 20 pg TCDD-EQ/g SPMD. Reactive clean-up of one of the bleached kraft mill effluent-exposed SPMD extracts on a sulfuric acid/silica gel column resulted in loss of the inducer(s), which suggested a polyaromatic hydrocarbon-type of inducing chemical(s), rather than a dioxin or furan inducer. SPMD deployments proved useful in the detection of inducers within the pulp mill process streams as extracts of SPMDs exposed to untreated bleached sulphite effluent were ten to twenty times as potent as those

Perilla frutescens leaves extract ameliorates ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin.

PubMed

Bae, Jung-Soo; Han, Mira; Shin, Hee Soon; Kim, Min-Kyoung; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

2017-01-04

Perilla frutescens (L.) Britt. (Lamiaceae) is a traditional herb that is consumed in East Asian countries as a traditional medicine. This traditional herb has been documented for centuries to treat various diseases such as depression, allergies, inflammation and asthma. However, the effect of Perilla frutescens on skin has not been characterized well. The present study aimed to investigate the effect of Perilla frutescens leaves extract (PLE) on ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin. Human dermal fibroblasts and Skh-1 hairless mice were irradiated with UV and treated with PLE. Protein and mRNA levels of various target molecules were analyzed by western blotting and quantitative RT-PCR, respectively. Histological changes of mouse skin were analyzed by H&E staining. To elucidate underlying mechanism of PLE, activator protein-1 (AP-1) DNA binding assay and the measurement of reactive oxygen species (ROS) were performed. PLE significantly inhibited basal and UV-induced MMP-1 and MMP-3 expression dose-dependently, and also decreased UV-induced phosphorylation of extracellular signal-regulated kinases and c-Jun N-terminal kinases. This inhibitory effects of PLE on MMP-1 and MMP-3 were mediated by reduction of ROS generation and AP-1 DNA binding activity induced by UV. Furthermore, PLE promoted type I procollagen production irrespective of UV irradiation. In the UV-irradiated animal model, PLE significantly reduced epidermal skin thickness and MMP-13 expression induced by UV. Our results demonstrate that PLE has the protective effect against UV-induced dermal matrix damage. Therefore, we suggest that PLE can be a potential agent for prevention of skin aging. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Fetal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin induces expression of the chemokine genes Cxcl4 and Cxcl7 in the perinatal mouse brain.

PubMed

Mitsui, Tetsuo; Taniguchi, Naofumi; Kawasaki, Nobuchika; Kagami, Yoshihiro; Arita, Jun

2011-04-01

Fetal exposure to dioxins affects brain development and influences behaviors in human and laboratory animals. However, the cellular target and mechanisms of the neurotoxic action of dioxins are largely unknown. To investigate the molecular basis for the neurotoxicity of dioxins, pregnant C57BL/6 mice were exposed to 5 µg kg(-1) body weight of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by a single gavage on gestational day 12.5 (GD 12.5), and gene expression of the whole fetal brain at GD 18.5 was profiled by DNA microarray analysis. The analysis revealed that the expression of two chemokine genes, Cxcl4 and Cxcl7, was up-regulated by TCDD exposure. Real-time PCR analysis verified that they were up-regulated by TCDD in both male and female brains, while the mRNA levels of a majority of other chemokines and their receptor genes were not affected. The up-regulation was TCDD dose-dependent and peaked at GD 15.5-18.5. In situ hybridization analysis showed that the Cxcl4 mRNA expression was localized in part of the surface of cerebral cortex and that the level was increased by TCDD treatment. These results suggest that Cxcl4 and Cxcl7 play a role in the development of neurobehavioral alterations that are triggered by in utero TCDD exposure and later surface in adults. Copyright © 2011 John Wiley & Sons, Ltd.

Dexamethasone ameliorates H₂S-induced acute lung injury by alleviating matrix metalloproteinase-2 and -9 expression.

PubMed

Wang, Jun; Zhang, Huazhong; Su, Chenglei; Chen, Junjie; Zhu, Baoli; Zhang, Hengdong; Xiao, Hang; Zhang, Jinsong

2014-01-01

Acute lung injury (ALI) is one of the fatal outcomes after exposure to high levels of hydrogen sulfide (H2S), and the matrix metalloproteinases (MMPs) especially MMP-2 and MMP-9 are believed to be involved in the development of ALI by degrading the extracellular matrix (ECM) of blood-air barrier. However, the roles of MMP-2 and MMP-9 in H2S-induced ALI and the mechanisms of dexamethasone (DXM) in treating ALI in clinical practice are still largely unknown. The present work was aimed to investigate the roles of MMP-2 and MMP-9 in H2S-induced ALI and the protective effects of DXM. In our study, SD rats were exposed to H2S to establish the ALI model and in parallel, A549 cells were incubated with NaHS (a H2S donor) to establish cell model. The lung HE staining, immunohistochemisty, electron microscope assay and wet/dry ratio were used to identify the ALI induced by H2S, then the MMP-2 and MMP-9 expression in both rats and A549 cells were detected. Our results revealed that MMP-2 and MMP-9 were obviously increased in both mRNA and protein level after H2S exposure, and they could be inhibited by MMP inhibitor doxycycline (DOX) in rat model. Moreover, DXM significantly ameliorated the symptoms of H2S-induced ALI including alveolar edema, infiltration of inflammatory cells and the protein leakage in BAFL via up-regulating glucocorticoid receptor(GR) to mediate the suppression of MMP-2 and MMP-9. Furthermore, the protective effects of DXM in vivo and vitro study could be partially blocked by co-treated with GR antagonist mifepristone (MIF). Our results, taken together, demonstrated that MMP-2 and MMP-9 were involved in the development of H2S-induced ALI and DXM exerted protective effects by alleviating the expression of MMP-2 and MMP-9. Therefore, MMP-2 and MMP-9 might represent novel pharmacological targets for the treatment of H2S and other hazard gases induced ALI.

Effects of aging on resistance to Trichinella spiralis infection in rodents exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

PubMed

Luebke, R W; Copeland, C B; Andrews, D L

1999-08-13

Immune function, including resistance to infection, decreases as humans and rodents age. We have shown that preinfection exposure of young (9-11 weeks) mice or rats to TCDD decreased resistance to Trichinella spiralis (Ts) infection, expressed as delayed onset or completion of parasite elimination and as increased muscle burdens of larvae. It has also been shown that aged mice express lower constitutive levels of resistance to Ts infection, compared to young adult animals. This study tested the hypothesis that the age-related decrease in constitutive levels of resistance to Ts infection exacerbates the decreased resistance to infection that follows TCDD exposure. This hypothesis addresses the concern that TCDD may pose a greater threat to the elderly than to the population at large. Animals were given a single oral dose of 1, 10, or 30 microg TCDD/kg, 7 days before infection. Eleven days later, young (approximately 10 weeks) control rodents had eliminated a greater proportion of the original parasite burden from the intestine than aged control animals. Nevertheless, parasite elimination was decreased by TCDD exposure only in young rodents. The effect of TCDD exposure on numbers of encysted larvae was evaluated only in rats. Increased larvae burdens occurred in young rats at 30 microg TCDD/kg and at 10 or 30 microg TCDD/kg in aged rats. Parasite-specific splenocyte and lymph node cell proliferation was suppressed following dioxin exposure in young mice; cells from aged mice were markedly less responsive to stimulation, yet less sensitive to TCDD exposure. The response to parasite antigens was not affected in aged rats exposed to TCDD, although elevated mitogen-driven B-cell proliferation was observed. These results indicate that age-related constitutive immunosuppression did not exacerbate TCDD-induced suppression of T-cell mediated adult parasite expulsion; rather, advanced age provided some degree of protection. On the other hand, a lower dose of TCDD was required

Altered Liver Proteoglycan/Glycosaminoglycan Structure as a Manifestation of Extracellular Matrix Remodeling upon BCG-induced Granulomatosis in Mice.

PubMed

Kim, L B; Shkurupy, V A; Putyatina, A N

2017-01-01

Experimental BCG-induced granulomatosis in mice was used to study changes in the dynamics of individual liver proteoglycan components reflecting phasic extracellular matrix remodeling, determined by the host-parasite interaction and associated with granuloma development. In the early BCG-granulomatosis period, the increase in individual proteoglycan components promotes granuloma formation, providing conditions for mycobacteria adhesion to host cells, migration of phagocytic cells from circulation, and cell-cell interaction leading to granuloma development and fibrosis. Later, reduced reserve capacity of the extracellular matrix, development of interstitial fibrosis and granuloma fibrosis can lead to trophic shortage for cells within the granulomas, migration of macrophages out of them, and development of spontaneous necrosis and apoptosis typical of tuberculosis.

Urinary Amino Acid Alterations in 3-Year-Old Children with Neurodevelopmental Effects due to Perinatal Dioxin Exposure in Vietnam: A Nested Case-Control Study for Neurobiomarker Discovery

PubMed Central

Nishijo, Muneko; Tai, Pham The; Anh, Nguyen Thi Nguyet; Nghi, Tran Ngoc; Nakagawa, Hideaki; Van Luong, Hoang; Anh, Tran Hai; Morikawa, Yuko; Waseda, Tomoo; Kido, Teruhiko; Nishijo, Hisao

2015-01-01

In our previous study of 3-year-old children in a dioxin contamination hot spot in Vietnam, the high total dioxin toxic equivalent (TEQ-PCDDs/Fs)-exposed group during the perinatal period displayed lower Bayley III neurodevelopmental scores, whereas the high 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-exposed group displayed increased autistic traits. In autistic children, urinary amino acid profiles have revealed metabolic alterations in the amino acids that serve as neurotransmitters in the developing brain. Therefore, our present study aimed to investigate the use of alterations in urinary amino acid excretion as biomarkers of dioxin exposure-induced neurodevelopmental deficits in highly exposed 3-year-old children in Vietnam. A nested case-control study of urinary analyses was performed for 26 children who were selected from 111 3-year-old children whose perinatal dioxin exposure levels and neurodevelopmental status were examined in follow-up surveys conducted in a dioxin contaminated hot spot. We compared urinary amino acid levels between the following 4 groups: (1) a high TEQ-PCDDs/Fs and high TCDD-exposed group; (2) a high TEQ-PCDDs/Fs but low TCDD-exposed group; (3) a low TEQ-PCDDs/Fs exposed and poorly developed group; and (4) a low TEQ-PCDDs/Fs exposed and well-developed group. Urinary levels of histidine and tryptophan were significantly decreased in the high TEQ-PCDDs/Fs and high TCDD group, as well as in the high TEQ-PCDDs/Fs but low TCDD group, compared with the low TEQ-PCDDs/Fs and well-developed group. However, the ratio of histidine to glycine was significantly lower only in the high TEQ-PCDDs/Fs and high TCDD group. Furthermore, urinary histidine levels and the ratio of histidine to glycine were significantly correlated with neurodevelopmental scores, particularly for language and fine motor skills. These results indicate that urinary histidine is specifically associated with dioxin exposure-induced neurodevelopmental deficits, suggesting that

Urinary amino acid alterations in 3-year-old children with neurodevelopmental effects due to perinatal dioxin exposure in Vietnam: a nested case-control study for neurobiomarker discovery.

PubMed

Nishijo, Muneko; Tai, Pham The; Anh, Nguyen Thi Nguyet; Nghi, Tran Ngoc; Nakagawa, Hideaki; Van Luong, Hoang; Anh, Tran Hai; Morikawa, Yuko; Waseda, Tomoo; Kido, Teruhiko; Nishijo, Hisao

2015-01-01

In our previous study of 3-year-old children in a dioxin contamination hot spot in Vietnam, the high total dioxin toxic equivalent (TEQ-PCDDs/Fs)-exposed group during the perinatal period displayed lower Bayley III neurodevelopmental scores, whereas the high 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-exposed group displayed increased autistic traits. In autistic children, urinary amino acid profiles have revealed metabolic alterations in the amino acids that serve as neurotransmitters in the developing brain. Therefore, our present study aimed to investigate the use of alterations in urinary amino acid excretion as biomarkers of dioxin exposure-induced neurodevelopmental deficits in highly exposed 3-year-old children in Vietnam. A nested case-control study of urinary analyses was performed for 26 children who were selected from 111 3-year-old children whose perinatal dioxin exposure levels and neurodevelopmental status were examined in follow-up surveys conducted in a dioxin contaminated hot spot. We compared urinary amino acid levels between the following 4 groups: (1) a high TEQ-PCDDs/Fs and high TCDD-exposed group; (2) a high TEQ-PCDDs/Fs but low TCDD-exposed group; (3) a low TEQ-PCDDs/Fs exposed and poorly developed group; and (4) a low TEQ-PCDDs/Fs exposed and well-developed group. Urinary levels of histidine and tryptophan were significantly decreased in the high TEQ-PCDDs/Fs and high TCDD group, as well as in the high TEQ-PCDDs/Fs but low TCDD group, compared with the low TEQ-PCDDs/Fs and well-developed group. However, the ratio of histidine to glycine was significantly lower only in the high TEQ-PCDDs/Fs and high TCDD group. Furthermore, urinary histidine levels and the ratio of histidine to glycine were significantly correlated with neurodevelopmental scores, particularly for language and fine motor skills. These results indicate that urinary histidine is specifically associated with dioxin exposure-induced neurodevelopmental deficits, suggesting that

2,3,7,8-tetrachlorodibenzo-p-dioxin potentially attenuates the gene expression of pituitary gonadotropin β-subunits in a fetal age-specific fashion: a comparative study using cultured pituitaries.

PubMed

Takeda, Tomoki; Yamamoto, Midori; Himeno, Masaru; Takechi, Shinji; Yamaguchi, Tadatoshi; Ishida, Takumi; Ishii, Yuji; Yamada, Hideyuki

2011-04-01

Our previous studies have demonstrated that maternal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a reduction in gonadotropin biosynthesis in the fetal pituitary, resulting in the attenuated expression of steroidogenic proteins in the fetal gonads and the impairment of sexual behaviors in adulthood. However, the mechanism of the attenuation remains unknown. To address this issue, we investigated whether TCDD affects the pituitary production of gonadotropins, using cultured pituitary. In the absence of gonadotropin-releasing hormone (GnRH), a regulator of gonadotropin biosynthesis, TCDD did not affect the expression of gonadotropin mRNAs both in fetal and postnatal pituitaries. On the other hand, in the presence of GnRH, TCDD interfered with the synthesis of gonadotropin β-subunit mRNAs only in the fetal pituitary. A protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate) and a PKA activator (8-bromoadenosine-3' 5'-cyclic monophosphate) induced the expression of gonadotropin mRNAs in the fetal pituitary. Among the subunits, only the induction of β-subunit was reduced by TCDD treatment. These results suggest that TCDD reduces gonadotropin biosynthesis via damage to GnRH-stimulated PKC and PKA signaling in a β-subunit- and fetal age-specific manner.

Human kidney stone matrix: Latent potential to restrain COM induced cytotoxicity and inflammatory response.

PubMed

Narula, Shifa; Tandon, Simran; Baligar, Prakash; Singh, Shrawan Kumar; Tandon, Chanderdeep

2017-12-25

Kidney stone disease is a multi-factorial disorder resulting from the interplay of various risk factors including lifestyle, environment and genetics along with metabolic activities inside the body. However, it is difficult to determine how these factors converge to promote stone disease. Extensive investigations of kidney stone composition at the molecular level have been carried out however; its impact on the complex mechanism of stone formation is still obscure. Hence, an in vitro study was designed to investigate the attenuation of calcium oxalate toxicity by human kidney stone matrix proteins on NRK-52E cells using flowcytometry, Western blotting, RT-PCR and immunofluorescence assays. Morphological alterations in cell-crystal interaction were assessed using scanning electron microscopy. Microscopic studies showed profound impairment of COM crystal structure as a consequence of protein-crystal interactions. RT-PCR analysis and immunocytochemistry of NRK-52E cells revealed the up-regulation of inflammatory and stress biomarkers OPN and HSP-70, respectively, in response to COM toxicity; which diminished significantly in the presence of kidney stone matrix proteins. The results of present study propose that the mechanism undertaken by matrix proteins to attenuate COM induced cytotoxicity could be attributed to the modulation of crystal structure, which subsequently restraint the inflammatory response and apoptotic cell death. The inference drawn through this study could provide better understanding of the intricate process of kidney stone formation. Copyright © 2017 Elsevier B.V. All rights reserved.

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a potential biomarker of angiogenesis in proliferative diabetic retinopathy.

PubMed

Abu El-Asrar, Ahmed M; Ahmad, Ajmal; Alam, Kaiser; Siddiquei, Mohammad Mairaj; Mohammad, Ghulam; Hertogh, Gert De; Mousa, Ahmed; Opdenakker, Ghislain

2017-11-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) promotes angiogenesis through matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) production. We investigated the expression levels of EMMPRIN and correlated these levels with VEGF, MMP-1 and MMP-9 in proliferative diabetic retinopathy (PDR). In addition, we examined the expression of EMMPRIN in the retinas of diabetic rats and the effect of EMMPRIN on the induction of angiogenesis regulatory factors in human retinal microvascular endothelial cells (HRMECs). Vitreous samples from 40 PDR and 19 non-diabetic patients, epiretinal membranes from 12 patients with PDR, retinas of rats and HRMECs were studied by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, Western blot analysis, zymography analysis and RT-PCR. We showed a significant increase in the expression of EMMPRIN, VEGF, MMP-1 and MMP-9 in vitreous samples from PDR patients compared with non-diabetic controls (p < 0.0001; p = 0.001; p = 0.009; p < 0.0001, respectively). Significant positive correlations were found between the levels of EMMPRIN and the levels of VEGF (r = 0.38; p = 0.003), MMP-1 (r = 0.36; p = 0.005) and MMP-9 (r = 0.46; p = 0.003). In epiretinal membranes, EMMPRIN was expressed in vascular endothelial cells and stromal cells. Significant increase of EMMPRIN mRNA was detected in rat retinas after induction of diabetes. EMMPRIN induced hypoxia-inducible factor-1α, VEGF and MMP-1 expression in HRMEC. These results suggest that EMMPRIN/MMPs/VEGF pathway is involved in PDR angiogenesis. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin administration and high-fat diet on the body weight and hepatic estrogen metabolism in female C3H/HeN mice

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

Zhu Baoting; Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers-State University of New Jersey, 164 Frelinghuysen Road, Piscataway, NJ 08854; Gallo, Michael A.

We studied the effect of administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by i.p. injection once every 2 weeks in combination with a high-fat (HF) diet for 8 or 16 weeks on the body and organ weight changes as well as on the hepatic enzyme activity for estrogen metabolism in C3H/HeN female mice. Administration of TCDD at 100 {mu}g/kg b.w. once every 2 weeks for 8 weeks increased the body weight by 46% in the HF diet-fed animals, but not in the regular diet-fed animals. This is the first observation suggesting that TCDD at a high dose (100 {mu}g/kg b.w.), but not atmore » lower doses (1 or 10 {mu}g/kg b.w.), may have a strong obesity-inducing effect in C3H/HeN mice fed an HF diet. While TCDD increased liver weight and decreased thymus weight in animals, these effects were enhanced by feeding animals an HF diet. Metabolism studies showed that TCDD administration for 8 or 16 weeks increased the liver microsomal activity for the 2- and 4-hydroxylation of 17{beta}-estradiol in animals fed a control diet, but surprisingly not in animals fed an HF diet. Treatment with TCDD dose-dependently increased the hepatic activity for the O-methylation of catechol estrogens in both control and HF diet-fed animals, and it also decreased the levels of liver microsomal sulfatase activity for hydrolysis of estrone-3-sulfate. TCDD did not significantly affect the hepatic enzyme activity for the glucuronidation or esterification of endogenous estrogens. It is suggested that enhanced metabolic inactivation of endogenous estrogens by hepatic estrogen-metabolizing enzymes in TCDD-treated, control diet-fed animals contributes importantly to the reduced incidence of estrogen-associated tumors in animals treated with TCDD.« less

Differential expression of lactic acid isomers, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-8 in vaginal fluid from women with vaginal disorders.

PubMed

Beghini, J; Linhares, I M; Giraldo, P C; Ledger, W J; Witkin, S S

2015-11-01

Do metabolites in vaginal samples vary between women with different vaginal disorders. Cross-sectional study. Campinas, Brazil. Seventy-seven women (39.9%) with no vaginal disorder, 52 women (26.9%) with vulvovaginal candidiasis (VVC), 43 women (22.3%) with bacterial vaginosis (BV), and 21 women (10.9%) with cytolytic vaginosis (CTV). Concentrations of D- and L-lactic acid, extracellular matrix metalloproteinase inducer (EMMPRIN), and matrix metalloproteinase-8 (MMP-8), and the influence of Candida albicans on EMMPRIN production by cultured vaginal epithelial cells, were determined by enzyme-linked immunosorbent assay (ELISA). Associations were determined by the Mann-Whitney U-test and by Spearman's rank correlation test. Metabolite levels and their correlation with diagnoses. Vaginal concentrations of D- and L-lactic acid were reduced from control levels in BV (P < 0.0001); L-lactic acid levels were elevated in CTV (P = 0.0116). EMMPRIN and MMP-8 concentrations were elevated in VVC (P < 0.0001). EMMPRIN and L-lactic acid concentrations (P ≤ 0.008), but not EMMPRIN and D-lactic acid, were correlated in all groups. EMMPRIN also increased in proportion with the ratio of L- to D-lactic acid in controls and in women with BV (P ≤ 0.009). Concentrations of EMMPRIN and MMP-8 were correlated in controls and women with VVC (P ≤ 0.0002). Candida albicans induced EMMPRIN release from vaginal epithelial cells. Vaginal secretions from women with BV are deficient in D- and L-lactic acid, women with VVC have elevated EMMPRIN and MMP-8 levels, and women with CTV have elevated L-lactic acid levels. These deviations may contribute to the clinical signs, symptoms, and sequelae that are characteristic of these disorders. © 2014 Royal College of Obstetricians and Gynaecologists.

Memantine inhibits degradation of the articular cartilage extracellular matrix induced by advanced glycation end products (AGEs).

PubMed

Zhao, Jijun; Yu, Yinghao; Wu, Zhaofeng; Wang, Ling; Li, Wei

2017-07-01

The accumulation of inflammation and cartilage damage induced by advanced glycation end products (AGEs) are important hallmarks of osteoarthritis (OA). Memantine is a clinically licensed drug used for the treatment of moderate and severe Alzheimer's disease. To date, little information has been reported regarding the effects of memantine on cartilage destruction. In this study, we investigated the protective effects of memantine on AGE-induced degradation of collagen II and aggrecans in human SW1353 chondrocytes. Our results indicate that memantine ameliorated AGE-induced degradation of collagen II and aggrecan at the post-translational level in SW1353 cells, which were mediated by matrix metalloproteinase-13 (MMP-13) and A disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4), respectively. Mechanistically, memantine was found to attenuate the upregulation of the transcriptional factor interferon response factor-1 (IRF-1) induced by AGEs, as well as activation of the JAK2/STAT1 pathway. Our findings suggest that memantine may have a potential therapeutic effect in OA. Copyright © 2017. Published by Elsevier Masson SAS.

Prediction of thermal cycling induced cracking in polymer matrix composites

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1993-01-01

This report summarizes the work done in the period February 1993 through July 1993 on the 'Prediction of Thermal Cycling Induced Cracking In Polymer Matrix Composites' program. An oral presentation of this work was given to Langley personnel in September of 1993. This document was prepared for archival purposes. Progress studies have been performed on the effects of spatial variations in material strength. Qualitative agreement was found with observed patterns of crack distribution. These results were presented to NASA Langley personnel in November 1992. The analytical methodology developed by Prof. McManus in the summer of 1992 (under an ASEE fellowship) has been generalized. A method for predicting matrix cracking due to decreasing temperatures and/or thermal cycling in all plies of an arbitrary laminate has been implemented as a computer code. The code also predicts changes in properties due to the cracking. Experimental progressive cracking studies on a variety of laminates were carried out at Langley Research Center. Results were correlated to predictions using the new methods. Results were initially mixed. This motivated an exploration of the configuration of cracks within laminates. A crack configuration study was carried out by cutting and/or sanding specimens in order to examine the distribution of cracks within the specimens. These investigations were supplemented by dye-penetrant enhanced X-ray photographs. The behavior of thin plies was found to be different from the behavior of thicker plies (or ply groups) on which existing theories are based. Significant edge effects were also noted, which caused the traditional metric of microcracking (count of cracks on a polished edge) to be very inaccurate in some cases. With edge and configuration taken into account, rough agreement with predictions was achieved. All results to date were reviewed with NASA Langley personnel in September 1993.

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts

PubMed Central

Seok, Jin Kyung

2015-01-01

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging. PMID:25954129

p-Coumaric Acid Attenuates UVB-Induced Release of Stratifin from Keratinocytes and Indirectly Regulates Matrix Metalloproteinase 1 Release from Fibroblasts.

PubMed

Seok, Jin Kyung; Boo, Yong Chool

2015-05-01

Ultraviolet (UV) radiation-induced loss of dermal extracellular matrix is associated with skin photoaging. Recent studies demonstrated that keratinocyte-releasable stratifin (SFN) plays a critical role in skin collagen metabolism by inducing matrix metalloproteinase 1 (MMP1) expression in target fibroblasts. In the present study, we examined whether SFN released from UVB-irradiated epidermal keratinocytes increases MMP1 release from dermal fibroblasts, and whether these events are affected by p-coumaric acid (p-CA), a natural phenolic compound with UVB-shielding and antioxidant properties. HaCaT cells were exposed to UVB in the absence and presence of p-CA, and the conditioned medium was used to stimulate fibroblasts in medium transfer experiments. The cells and media were analyzed to determine the expressions/releases of SFN and MMP1. UVB exposure increased SFN release from keratinocytes into the medium. The conditioned medium of UVB-irradiated keratinocytes increased MMP1 release from fibroblasts. The depletion of SFN using a siRNA rendered the conditioned medium of UVB-irradiated keratinocytes ineffective at stimulating fibroblasts to release MMP1. p-CA mitigated UVB-induced SFN expression in keratinocytes, and attenuated the MMP1 release by fibroblasts in medium transfer experiments. In conclusion, the present study demonstrated that the use of UV absorbers such as p-CA would reduce UV-induced SFN-centered signaling events involved in skin photoaging.

Calcifying Cystic Odontogenic Tumour: immunohistochemical expression of matrix metalloproteinases, their inhibitors (TIMPs and RECK) and inducer (EMMPRIN).

PubMed

Prosdócimi, Fábio C; Rodini, Camila O; Sogayar, Mari C; Sousa, Suzana C O M; Xavier, Flávia C A; Paiva, Katiúcia B S

2014-08-01

Calcifying cyst odontogenic tumour (CCOT) is a rare benign cystic neoplasm of odontogenic origin. MMPs are responsible for extracellular matrix remodelling and, together their inhibitors and inducer, determinate the level of its turnover in pathological processes, leading to an auspicious microenvironment for tumour development. Thus, our goal was to evaluate matrix metalloproteinases (MMPs-2, -7, -9 and -14), their inhibitors (TIMPs-2, -3, -4 and RECK) and its inductor (EMMPRIN) expression in CCOT. We used 18 cases of CCOT submitted to immunolocalization of the target proteins and analysed in both neoplastic odontogenic epithelial and stromal compartments. All molecules evaluated were expressed in both compartments in CCOT. In epithelial layer, immunostaining for MMPs, TIMPs, RECK and EMMPRIN was found in basal, suprabasal spindle and stellate cells surrounding ghost cells and ghost cells themselves, except for MMP-9 and TIMP-2 which were only expressed by ghost cells. In stromal compartment, extracellular matrix, mesenchymal (MC) and endothelial cells (EC) were positive for MMP-2, -7, TIMP-3 and -4, while MMP-9, TIMP-2 and RECK were positive only in MC and MMP-14 only in EC. Statistical significance difference was found between both compartments for MMP-9 (P < 0.001), RECK (P = 0.004) and EMMPRIN (P < 0.001), being more expressed in epithelium than in stroma. Positive correlation between both stromal EMMPRIN and RECK expression was found (R = 0.661, P = 0.003). We concluded that these proteins/enzymes are differentially expressed in both epithelium and stroma of CCOT, suggesting an imbalance between MMPs and their inducer/inhibitors may contribute on the tumour behaviour. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Myc-induced anchorage of the rDNA IGS region to nucleolar matrix modulates growth-stimulated changes in higher-order rDNA architecture.

PubMed

Shiue, Chiou-Nan; Nematollahi-Mahani, Amir; Wright, Anthony P H

2014-05-01

Chromatin domain organization and the compartmentalized distribution of chromosomal regions are essential for packaging of deoxyribonucleic acid (DNA) in the eukaryotic nucleus as well as regulated gene expression. Nucleoli are the most prominent morphological structures of cell nuclei and nucleolar organization is coupled to cell growth. It has been shown that nuclear scaffold/matrix attachment regions often define the base of looped chromosomal domains in vivo and that they are thereby critical for correct chromosome architecture and gene expression. Here, we show regulated organization of mammalian ribosomal ribonucleic acid genes into distinct chromatin loops by tethering to nucleolar matrix via the non-transcribed inter-genic spacer region of the ribosomal DNA (rDNA). The rDNA gene loop structures are induced specifically upon growth stimulation and are dependent on the activity of the c-Myc protein. Matrix-attached rDNA genes are hypomethylated at the promoter and are thus available for transcriptional activation. rDNA genes silenced by methylation are not recruited to the matrix. c-Myc, which has been shown to induce rDNA transcription directly, is physically associated with rDNA gene looping structures and the intergenic spacer sequence in growing cells. Such a role of Myc proteins in gene activation has not been reported previously. © 2014 The Author(s). Published by Oxford University Press [on behalf of Nucleic Acids Research].

Aryl hydrocarbon receptor-mediated activity of atmospheric particulate matter from an urban and a rural site in Switzerland

NASA Astrophysics Data System (ADS)

Wenger, Daniela; Gerecke, Andreas C.; Heeb, Norbert V.; Hueglin, Christoph; Seiler, Cornelia; Haag, Regula; Naegeli, Hanspeter; Zenobi, Renato

Atmospheric particulate matter (PM) is an air-suspended mixture of solid and liquid particles that vary in size, shape, and chemical composition. Long-term exposure to elevated concentrations of fine atmospheric particles is considered to pose a health threat to humans and animals. In this context, it has been hypothesized that toxic chemicals such as polycyclic aromatic hydrocarbons (PAHs) play an important role. Some PAHs are known to be carcinogenic and it has been shown that carcinogenic effects of PAHs are mediated by the aryl hydrocarbon receptor (AhR). In this study, PM1 was collected at a rural and an urban traffic site during an intense winter smog period, in which concentration of PM1 often exceeded 50 μg m -3. We applied an in vitro reporter gene assay (DR-CALUX) to detect and quantify PM1-associated chemicals that induce AhR-mediated gene expression. This activity was expressed as CALUX equivalents of 2,3,7,8-tetrachlorodibenzodioxin (PM-TCDD-CEQs). In addition, concentrations of PAHs in the PM1 extracts were determined using gas chromatography/high-resolution mass spectrometry. Concentrations of PM-TCDD-CEQs ranged from 10 to 85 pg m -3 and from 19 to 87 pg m -3 at the urban and rural site, respectively. By the use of known relative potency factors, the measured concentration of a PAH was converted into a PAH-TCDD-CEQ concentration. ΣPAH-TCDD-CEQ and PM-TCDD-CEQ were highly correlated at both sites ( r2 = 0.90 and 0.69). The calculated ΣPAH-TCDD-CEQs explain between 2% and 20% of the measured PM-TCDD-CEQs. Benzo[ k]fluoranthene was the most important PAH causing approximately 60% of the total ΣPAH-TCDD-CEQ activity. In contrast to NO, CO, PM10, and PM1, the concentration of PM-TCDD-CEQs showed no significant difference between the two sites. No indications were found that road traffic emissions caused elevated concentrations of PM-TCDD-CEQs at the urban traffic site.

Epigenetic Programming of Breast Cancer and Nutrition Prevention

DTIC Science & Technology

2011-05-01

is to test the role of xenobiotics and food compounds that bind the aromatic hydrocarbon receptor (AhR). AhR-ligands include the dioxin -like and...tumor promoter 2,3,7,8 tetrachlorobenzo-p- dioxin (TCDD). The activated AhR regulates transcription through binding to xenobiotic response elements (XRE...phytoalexin resveratrol, selected as a prototype dietary AhR antagonist, antagonizes at physiologically relevant doses (1  mol /L) the TCDD-induced

Cigarette smoke extract induces select matrix metalloproteinases and integrin expression in periodontal ligament fibroblasts.

PubMed

Bulmanski, Zachary; Brady, Matthew; Stoute, Diana; Lallier, Thomas E

2012-06-01

The periodontal ligament (PDL) is the connective tissue that anchors the cementum of the teeth to the alveolar bone. PDL fibroblasts are responsible for the production of collagen and remodeling of the PDL. Periodontal disease is increased among smokers in both incidence and severity. This study examines the direct effect of smoking on PDL fibroblasts and their production of various matrix components and remodeling enzymes. PDL cells were plated for 1 day and then treated with various concentrations of cigarette smoke extract (CSE). Survival of PDL cells was quantified after exposure to CSE, and their ability to contract three-dimensional collagen gels was examined. Changes in transcript expression after CSE treatment was compared using reverse transcription-polymerase chain reaction analysis for matrix metalloproteinases (MMPs), collagens, and integrins. Treatment with CSE-induced cell death at concentrations of ≥5%. PDL-cell-induced collagen gel contraction was reduced at concentrations of 1.5% CSE. Treatment with CSE selectively increased the expression of collagen Vα3 and decreased collagen XIα1. CSE increased the expression of MMP1 and MMP3 and, to a lesser extent, MMP2 and MMP8. CSE also increased the expression of integrins α1, α2, and α10 (collagen receptors) and α9 (a tenascin receptor). This study shows that cigarette smoking has local effects on the cells of the PDL. CSE reduced survival of PDL cells and their ability to contract collagen matrices. CSE also altered the expression of molecules known to provide the structural integrity of the ligament by altering collagen synthesis and remodeling as well as cell adhesion.

Peptide-matrix-mediated gene transfer of an oxygen-insensitive hypoxia-inducible factor-1alpha variant for local induction of angiogenesis.

PubMed

Trentin, Diana; Hall, Heike; Wechsler, Sandra; Hubbell, Jeffrey A

2006-02-21

Hypoxia-inducible factor (HIF) constitutes a target in therapeutic angiogenesis. HIF-1alpha functions as a sensor of hypoxia and induces expression of vascular endothelial growth factor (VEGF), which then induces angiogenesis. To explore the potential of HIF-1alpha gene therapy in stimulating wound healing, we delivered a gene encoding a stabilized form of HIF-1alpha, lacking the oxygen-sensitive degradation domain, namely HIF-1alpha deltaODD, by using a previously characterized peptide-based gene delivery vector in fibrin as a surgical matrix. The peptide vector consisted of multiple domains: (i) A cysteine-flanked lysine hexamer provided DNA interactions that were stable extracellularly but destabilized intracellularly after reduction of the formed disulfide bonds. This DNA-binding domain was fused to either (ii) a fibrin-binding peptide for entrapment within the matrix or (iii) a nuclear localization sequence for efficient nuclear targeting. The HIF-1alpha deltaODD gene was expressed and translocated to the nucleus under normoxic conditions, leading to up-regulation of vascular endothelial growth factor (VEGF)-A165 mRNA and protein levels in vitro. When the peptide-DNA nanoparticles entrapped in fibrin matrices were applied to full-thickness dermal wounds in the mouse (10 microg per wound in 30 microl of fibrin), angiogenesis was increased comparably strongly to that induced by VEGF-A165 protein (1.25 microg per wound in 30 microl of fibrin). However, the maturity of the vessels induced by HIF-1alpha deltaODD was significantly higher than that induced by VEGF-A165 protein, as shown by stabilization of the neovessels with smooth muscle. Nonviral, local administration of this potent angiogenesis-inducing gene by using this peptide vector represents a powerful approach in tissue engineering and therapeutic angiogenesis.

Twinning-induced plasticity (TWIP) and work hardening in Ti-based metallic glass matrix composites.

PubMed

Fan, J; Qiao, J W; Wang, Z H; Rao, W; Kang, G Z

2017-05-12

The present study demonstrates that Ti-based metallic glass matrix composites (MGMCs) with a normal composition of Ti 43 Zr 32 Ni 6 Ta 5 Be 14 containing ductile dendrites dispersed in the glass matrix has been developed, and deformation mechanisms about the tensile property have been investigated by focusing on twinning-induced plasticity (TWIP) effect. The Ti-based MGMC has excellent tensile properties and pronounced tensile work-hardening capacity, with a yield strength of 1100 MPa and homogeneous elongation of 4%. The distinguished strain hardening is ascribed to the formation of deformation twinning within the dendrites. Twinning generated in the dendrites works as an obstacle for the rapid propagation of shear bands, and then, the localized necking is avoided, which ensures the ductility of such kinds of composites. Besides, a finite-element model (FEM) has been established to explain the TWIP effect which brings out a work-hardening behavior in the present MGMC instead of a localized strain concentration. According to the plasticity theory of traditional crystal materials and some new alloys, TWIP effect is mainly controlled by stacking fault energy (SFE), which has been analyzed intensively in the present MGMC.

Laser-induced breakdown spectroscopy for quantitative spectrochemical analysis of geological materials: effects of the matrix and simultaneous determination.

PubMed

Anzano, Jesús M; Villoria, Mark A; Ruíz-Medina, Antonio; Lasheras, Roberto J

2006-08-11

A microscopic laser-induced breakdown spectrometer was used to evaluate the analytical matrix effect commonly observed in the analysis of geological materials. Samples were analyzed in either the powder or pressed pellet forms. Calibration curves of a number of iron and aluminum compounds showed a linear relationship between the elemental concentration and peak intensity. A direct determination of elemental content can thus be made from extrapolation on these calibration curves. To investigate matrix effects, synthetic model samples were prepared from various iron and aluminum compounds spiked with SiO2 and CaCO3. The addition of these matrices had a pronounced analytical effect on those compounds prepared as pressed pellets. However, results indicated the absence of matrix effects when the samples were presented to the laser as loose powders on tape and results were compared to certified values, indicating the reliability of this approach for accurate analysis, provided the sample particle diameters are greater than approximately 100 microm. Finally, the simultaneous analysis of two different elements was demonstrated using powders on tape.

Dry Arthroscopy With a Retraction System for Matrix-Aided Cartilage Repair of Patellar Lesions

PubMed Central

Sadlik, Boguslaw; Wiewiorski, Martin

2014-01-01

Several commercially available cartilage repair techniques use a natural or synthetic matrix to aid cartilage regeneration (e.g., autologous matrix–induced chondrogenesis or matrix-induced cartilage implantation). However, the use of matrix-aided techniques during conventional knee joint arthroscopy under continuous irrigation is challenging. Insertion and fixation of the matrix can be complicated by the presence of fluid and the confined patellofemoral joint space with limited access to the lesion. To overcome these issues, we developed a novel arthroscopic approach for matrix-aided cartilage repair of patellar lesions. This technical note describes the use of dry arthroscopy assisted by a minimally invasive retraction system. An autologous matrix–induced chondrogenesis procedure is used to illustrate this novel approach. PMID:24749035

AhR-mediated gene expression in the developing mouse telencephalon.

PubMed

Gohlke, Julia M; Stockton, Pat S; Sieber, Stella; Foley, Julie; Portier, Christopher J

2009-11-01

We hypothesize that TCDD-induced developmental neurotoxicity is modulated through an AhR-dependent interaction with key regulatory neuronal differentiation pathways during telencephalon development. To test this hypothesis we examined global gene expression in both dorsal and ventral telencephalon tissues in E13.5 AhR-/- and wildtype mice exposed to TCDD or vehicle. Consistent with previous biochemical, pathological and behavioral studies, our results suggest TCDD initiated changes in gene expression in the developing telencephalon are primarily AhR-dependent, as no statistically significant gene expression changes are evident after TCDD exposure in AhR-/- mice. Based on a gene regulatory network for neuronal specification in the developing telencephalon, the present analysis suggests differentiation of GABAergic neurons in the ventral telencephalon is compromised in TCDD exposed and AhR-/- mice. In addition, our analysis suggests Sox11 may be directly regulated by AhR based on gene expression and comparative genomics analyses. In conclusion, this analysis supports the hypothesis that AhR has a specific role in the normal development of the telencephalon and provides a mechanistic framework for neurodevelopmental toxicity of chemicals that perturb AhR signaling.

Creep and stress relaxation induced by interface diffusion in metal matrix composites

NASA Astrophysics Data System (ADS)

Li, Yinfeng; Li, Zhonghua

2013-03-01

An analytical solution is developed to predict the creep rate induced by interface diffusion in unidirectional fiber-reinforced and particle reinforced composites. The driving force for the interface diffusion is the normal stress acting on the interface, which is obtained from rigorous Eshelby inclusion theory. The closed-form solution is an explicit function of the applied stress, volume fraction and radius of the fiber, as well as the modulus ratio between the fiber and the matrix. It is interesting that the solution is formally similar to that of Coble creep in polycrystalline materials. For the application of the present solution in the realistic composites, the scale effect is taken into account by finite element analysis based on a unit cell. Based on the solution, a closed-form solution is also given as a description of stress relaxation induced by interfacial diffusion under constant strain. In addition, the analytical solution for the interface stress presented in this study gives some insight into the relationship between the interface diffusion and interface slip. This work was supported by the financial support from the Nature Science Foundation of China (No. 10932007), the National Basic Research Program of China (No. 2010CB631003/5), and the Doctoral Program of Higher Education of China (No. 20100073110006).

Irradiation of skin with visible light induces reactive oxygen species and matrix-degrading enzymes.

PubMed

Liebel, Frank; Kaur, Simarna; Ruvolo, Eduardo; Kollias, Nikiforos; Southall, Michael D

2012-07-01

Daily skin exposure to solar radiation causes cells to produce reactive oxygen species (ROS), which are a primary factor in skin damage. Although the contribution of the UV component to skin damage has been established, few studies have examined the effects of non-UV solar radiation on skin physiology. Solar radiation comprises <10% of UV, and thus the purpose of this study was to examine the physiological response of skin to visible light (400-700 nm). Irradiation of human skin equivalents with visible light induced production of ROS, proinflammatory cytokines, and matrix metalloproteinase (MMP)-1 expression. Commercially available sunscreens were found to have minimal effects on reducing visible light-induced ROS, suggesting that UVA/UVB sunscreens do not protect the skin from visible light-induced responses. Using clinical models to assess the generation of free radicals from oxidative stress, higher levels of free radical activity were found after visible light exposure. Pretreatment with a photostable UVA/UVB sunscreen containing an antioxidant combination significantly reduced the production of ROS, cytokines, and MMP expression in vitro, and decreased oxidative stress in human subjects after visible light irradiation. Taken together, these findings suggest that other portions of the solar spectrum aside from UV, particularly visible light, may also contribute to signs of premature photoaging in skin.

Portrait of Matrix Gene Expression in Candida glabrata Biofilms with Stress Induced by Different Drugs

PubMed Central

2018-01-01

(1) Background: Candida glabrata is one of the most significant Candida species associated with severe cases of candidiasis. Biofilm formation is an important feature, closely associated with antifungal resistance, involving alterations of gene expression or mutations, which can result in the failure of antifungal treatments. Hence, the main goal of this work was to evaluate the role of a set of genes, associated with matrix production, in the resistance of C. glabrata biofilms to antifungal drugs. (2) Methods: the determination of the expression of BGL2, XOG1, FKS1, FKS2, GAS2, KNH1, UGP1, and MNN2 genes in 48-h biofilm’s cells of three C. glabrata strains was performed through quantitative real-time PCR (RT-qPCR), after contact with Fluconazole (Flu), Amphotericin B (AmB), Caspofungin (Csf), or Micafungin (Mcf). (3) Results: Mcf induced a general overexpression of the selected genes. It was verified that the genes related to the production of β-1,3-glucans (BGL2, XOG1, GAS2) had the highest expressions. (4) Conclusion: though β-1,6-glucans and mannans are an essential part of the cell and biofilm matrix, C. glabrata biofilm cells seem to contribute more to the replacement of β-1,3-glucans. Thus, these biopolymers seem to have a greater impact on the biofilm matrix composition and, consequently, a role in the biofilm resistance to antifungal drugs. PMID:29642649

PEP-1-SIRT2-induced matrix metalloproteinase-1 and -13 modulates type II collagen expression via ERK signaling in rabbit articular chondrocytes.

PubMed

Eo, Seong-Hui; Choi, Soo Young; Kim, Song Ja

2016-11-01

Matrix metalloproteinases (MMPs) are critical for the degradation of the extracellular matrix (ECM), which includes cartilage-specific collagen types I, II and XI. We previously found that PEP-1-sirtuin (SIRT)2 could induce dedifferentiation of articular chondrocytes; however, the underlying mechanisms remains unclear. We addressed this in the present study by examining the association between PEP-1-SIRT2 and the expression of MMP-1 and MMP-13 and type II collagen in rabbit articular chondrocytes. We found that PEP-1-SIRT2 increased MMP-1 and -13 expression in a dose- and time-dependent manner, as determined by western blotting. A similar trend in MMP-1 and -13 levels was observed in cultures during expansion to four passages. Pharmacological inhibition of MMP-1 and -13 blocked the PEP-1-SIRT2-induced decrease in type II collagen level. Phosphorylation of extracellular regulated kinase (ERK) was increased by PEP-1-SIRT2; however, treatment with the mitogen-activated protein kinase inhibitor PD98059 suppressed PEP-1-SIRT2-induced MMP-1 and -13 expression and dedifferentiation while restoring type II collagen expression in passage 2 cells. These results suggest that PEP-1-SIRT2 promotes MMP-induced dedifferentiation via ERK signaling in articular chondrocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

Increased expression of matrix metalloproteinases mediates thromboxane A2-induced invasion in lung cancer cells.

PubMed

Li, Xiuling; Tai, Hsin-Hsiung

2012-07-01

Thromboxane A(2) receptor (TP) has been shown to play an important role in multiple aspects of cancer development including regulation of tumor growth, survival and metastasis. Here we report that TP mediates cancer cell invasion by inducing expression of matrix metalloproteinases (MMPs). TP agonist, I-BOP, significantly elevated MMP-1, MMP-3, MMP-9 and MMP-10 mRNA levels in A549 human lung adenocarcinoma cells overexpressing TPα or TPβ. The secretion of MMP-1 and MMP-9 in conditioned media was determined using Western blot analysis and zymographic assay. Signaling pathways of I-BOP-induced MMP-1 expression were examined in further detail as a model system for MMPs induction. Signaling molecules involved in I-BOP-induced MMP-1 expression were identified by using specific inhibitors including small interfering (si)-RNAs of signaling molecules and promoter reporter assay. The results indicate that I-BOP-induced MMP-1 expression is mediated by protein kinase C (PKC), extracellular signal-regulated kinase (ERK)-activator protein-1(AP-1) and ERK-CCAAT/enhancer-binding protein β (C/EBPβ) pathways. I-BOP-induced cellular invasiveness of A549 cells expressing TPα or TPβ was determined by invasion assay. GM6001, a general inhibitor of MMPs, decreased basal and I-BOP-induced cell invasion. Knockdown of MMP-1 and MMP-9 by their respective siRNA partially reduced I-BOP-stimulated cell invasion suggesting that other MMPs induced by I-BOP were also involved. Our studies establish the relationship between TP and MMPs in cancer cell invasion and suggest that the thromboxane A(2) (TXA(2))-TP signaling is a potential therapeutic target for cancer invasion and metastasis.

Role of extracellular matrix in regulation of staurosporine-induced apoptosis in breast cancer cells.

PubMed

Vasaturo, F; Malacrino, C; Sallusti, E; Coppotelli, G; Birarelli, P; Giuffrida, A; Albonici, L; Simonelli, L; Modesti, A; Modesti, M; Scarpa, S

2005-04-01

Autocrine and paracrine mechanisms modulate the synthesis and secretion of extracellular matrix (ECM); moreover, each component of the ECM is capable of modulating the synthesis and release of other ECM molecules. Therefore, the synthesis of ECM glycoprotein fibronectin and laminin was studied in the human breast cancer cell lines MCF7 and MDA MB 23, plated on different ECM. Our results showed that the cells plated on a fibronectin substrate increased laminin synthesis: this event correlated with an increase in alpha2 and alpha3 integrin subunits. Staurosporine-induced apoptosis was then analyzed in the cell lines plated on different ECM. Staurosporine treatment determined the apoptosis of 35 and 33% respectively of MDA MB 231 and MCF7; these values increased to 60 and 64% in cells plated on laminin, to 48 and 63% in cells plated on fibronectin and to 64 and 69% in cells plated on matrigel. Moreover, staurosporine treatment decreased bcl-2 expression in the cells plated on fibronectin and laminin. Yet, staurosporine treatment determined PARP cleavage and PARP partial disappearance when the cells were plated on matrigel. Finally, a partial loss of function mutant Ras protein that activated only Raf pathway, was expressed in MCF7, in order to identify whether the increase of apoptosis induced by extracellular matrix involved the Raf/MAP kinase pathway. The increase of apoptosis of the cells plated on matrigel suggested that the activation of the Raf pathway is probably involved in the decrease of survival on matrigel. These data demonstrate that the modification of ECM modulates the apoptotic process of breast cancer cells and suggest that it is worthwhile to dissect the role of ECM in the control of apoptotic process.

Betaine prevents homocysteine-induced memory impairment via matrix metalloproteinase-9 in the frontal cortex.

PubMed

Kunisawa, K; Nakashima, N; Nagao, M; Nomura, T; Kinoshita, S; Hiramatsu, M

2015-10-01

Betaine plays important roles that include acting as a methyl donor and converting homocysteine (Hcy) to methionine. Elevated plasma Hcy levels are known as hyperhomocysteinemia (HHcy) and contribute to impairments of learning and memory. Although it is commonly known that betaine plays an important role in Hcy metabolism, the effects of betaine on Hcy-induced memory impairment have not been investigated. Previously, we demonstrated the beneficial effects of betaine on acute stress and lipopolysaccharide-induced memory impairment. In the present study, we investigated whether betaine ameliorates Hcy-induced memory impairment and the underlying mechanisms of this putative effect. Mice were treated with Hcy (0.162mg/kg, s.c.) twice a day for nine days, and betaine (25mg/kg, s.c.) was administered 30min before the Hcy injections. The memory functions were evaluated using a spontaneous alternation performance test (Y-maze) at seven days and a step-down type passive avoidance test (SD) at nine and ten days after Hcy injection. We found that betaine suppressed the memory impairment induced by repeated Hcy injections. However, the blood concentrations of Hcy were significantly increased in the Hcy-treated mice immediately after the passive avoidance test, and betaine did not prevent this increase. Furthermore, Hcy induces redox stress in part by activating matrix metalloproteinase-9 (MMP-9), which leads to BBB dysfunction. Therefore, we tested whether betaine affected MMP-9 activity. Interestingly, treatment with betaine significantly inhibited Hcy-induced MMP-9 activity in the frontal cortex but not in the hippocampus after acute Hcy injection. These results suggest that the changes in MMP-9 activity after betaine treatment might have been partially responsible for the amelioration of the memory deficits and that MMP-9 might be a candidate therapeutic target for HHcy. Copyright © 2015 Elsevier B.V. All rights reserved.

Fibroblast growth factor receptor inhibition induces loss of matrix MCL1 and necrosis in cholangiocarcinoma.

PubMed

Kabashima, Ayano; Hirsova, Petra; Bronk, Steven F; Hernandez, Matthew C; Truty, Mark J; Rizvi, Sumera; Kaufmann, Scott H; Gores, Gregory J

2018-03-08

Myeloid cell leukemia 1 (MCL1), a prosurvival member of the BCL2 protein family, has a pivotal role in human cholangiocarcinoma (CCA) cell survival. We previously reported that fibroblast growth factor receptor (FGFR) signalling mediates MCL1-dependent survival of CCA cells in vitro and in vivo. However, the mode and mechanisms of cell death in this model were not delineated. Human CCA cell lines were treated with the pan-FGFR inhibitor LY2874455 and the mode of cell death examined by several complementary assays. Mitochondrial oxidative metabolism was examined using a XF24 extracellular flux analyser. The efficiency of FGFR inhibition in patient-derived xenografts (PDX) was also assessed. CCA cells expressed two species of MCL1, a full-length form localised to the outer mitochondrial membrane, and an N terminus-truncated species compartmentalised within the mitochondrial matrix. The pan-FGFR inhibitor LY2874455 induced non-apoptotic cell death in the CCA cell lines associated with cellular depletion of both MCL1 species. The cell death was accompanied by failure of mitochondrial oxidative metabolism and was most consistent with necrosis. Enforced expression of N terminus-truncated MCL1 targeted to the mitochondrial matrix, but not full-length MCL1 targeted to the outer mitochondrial membrane, rescued cell death and mitochondrial function. LY2874455 treatment of PDX-bearing mice was associated with tumour cell loss of MCL1 and cell necrosis. FGFR inhibition induces loss of matrix MCL1, resulting in cell necrosis. These observations support a heretofore unidentified, alternative MCL1 survival function, namely prevention of cell necrosis, and have implications for treatment of human CCA. Herein, we report that therapeutic inhibition of a cell receptor expressed by bile duct cancer cells resulted in the loss of a critical survival protein termed MCL1. Cellular depletion of MCL1 resulted in the death of the cancer cells by a process characterised by cell rupture. Cell

Rosmarinic acid induces rabbit articular chondrocyte differentiation by decreases matrix metalloproteinase-13 and inflammation by upregulating cyclooxygenase-2 expression.

PubMed

Eo, Seong-Hui; Kim, Song Ja

2017-09-18

Matrix metalloproteinases (MMPs) are known to play an important role in the degradation of the extracellular matrix and the pathological progression of osteoarthritis (OA). The natural polyphenolic compound rosmarinic acid (Ros. A) has been shown to suppress the inhibitory activity of matrix metalloproteinases (MMPs). However, the effects of Ros. A on OA have not been investigated. In the current study, primary articular chondrocytes were cultured from rabbit articular cartilage and treated with Ros. A. Phenotypic characterization was performed by western blotting to assess specific markers, prostaglandin E 2 (PGE 2 ) assays, and alcian blue staining to measure sulfated-proteoglycan production. We report that in rabbit articular chondrocytes, Ros. A increased type II collagen, sulfated-proteoglycan, cyclooxygenase-2 (COX-2), and PGE 2 production in a dose- and time-dependent manner. Furthermore, Ros. A suppressed the expression of MMP-13. In addition, treatment with Ros A activated extracellular signal-regulated kinase (ERK)-1/2 and p38 kinase signaling pathways. Inhibition of MMP-13 enhanced Ros. A-induced type II collagen expression and sulfated-proteoglycan synthesis but COX-2 and PGE 2 production were unchanged. Ros. A-mediated up-regulation of ERK phosphorylation was abolished by the MEK inhibitor, PD98059, which prevented induction of the associated inflammatory response. Inhibition of p38 kinase with SB203580 enhanced the increase in type II collagen expression via Ros. A-mediated down-regulation of MMP-13. Results suggest that ERK-1/2 regulates Ros. A-induced inflammation and that p38 regulates differentiation by inhibiting MMP-13 in rabbit articular chondrocytes.

Nicotine-induced retardation of chondrogenesis through down-regulation of IGF-1 signaling pathway to inhibit matrix synthesis of growth plate chondrocytes in fetal rats

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

Deng, Yu; Cao, Hong; Cu, Fenglong

Previous studies have confirmed that maternal tobacco smoking causes intrauterine growth retardation (IUGR) and skeletal growth retardation. Among a multitude of chemicals associated with cigarette smoking, nicotine is one of the leading candidates for causing low birth weights. However, the possible mechanism of delayed chondrogenesis by prenatal nicotine exposure remains unclear. We investigated the effects of nicotine on fetal growth plate chondrocytes in vivo and in vitro. Rats were given 2.0 mg/kg·d of nicotine subcutaneously from gestational days 11 to 20. Prenatal nicotine exposure increased the levels of fetal blood corticosterone and resulted in fetal skeletal growth retardation. Moreover, nicotinemore » exposure induced the inhibition of matrix synthesis and down-regulation of insulin-like growth factor 1 (IGF-1) signaling in fetal growth plates. The effects of nicotine on growth plates were studied in vitro by exposing fetal growth plate chondrocytes to 0, 1, 10, or 100 μM of nicotine for 10 days. Nicotine inhibited matrix synthesis and down-regulated IGF-1 signaling in chondrocytes in a concentration-dependent manner. These results suggest that prenatal nicotine exposure induces delayed chondrogenesis and that the mechanism may involve the down-regulation of IGF-1 signaling and the inhibition of matrix synthesis by growth plate chondrocytes. The present study aids in the characterization of delayed chondrogenesis caused by prenatal nicotine exposure, which might suggest a candidate mechanism for intrauterine origins of osteoporosis and osteoarthritis. - Highlights: ► Prenatal nicotine-exposure could induce delayed chondrogenesis in fetal rats. ► Nicotine inhibits matrix synthesis of fetal growth plate chondrocytes. ► Nicotine inhibits IGF-1 signaling pathway in fetal growth plate chondrocytes.« less

Differential expression profiling of the hepatic proteome in a rat model of dioxin resistance: correlation with genomic and transcriptomic analyses.

PubMed

Pastorelli, Roberta; Carpi, Donatella; Campagna, Roberta; Airoldi, Luisa; Pohjanvirta, Raimo; Viluksela, Matti; Hakansson, Helen; Boutros, Paul C; Moffat, Ivy D; Okey, Allan B; Fanelli, Roberto

2006-05-01

One characteristic feature of acute 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity is dramatic interspecies and interstrain variability in sensitivity. This complicates dioxin risk assessment for humans. However, this variability also provides a means of characterizing mechanisms of dioxin toxicity. Long-Evans (Turku/AB) rats are orders of magnitude more susceptible to TCDD lethality than Han/Wistar (Kuopio) rats, and this difference constitutes a very useful model for identifying mechanisms of dioxin toxicity. We adopted a proteomic approach to identify the differential effects of TCDD exposure on liver protein expression in Han/Wistar rats as compared with Long-Evans rats. This allows determination of which, if any, protein markers are indicative of differences in dioxin susceptibility and/or responsible for conferring resistance. Differential protein expression in total liver protein was assessed using two-dimensional gel electrophoresis, computerized gel image analysis, in-gel digestion, and mass spectrometry. We observed significant changes in the abundance of several proteins, which fall into three general classes: (i) TCDD-independent and exclusively strain-specific (e.g. isoforms of the protein-disulfide isomerase A3, regucalcin, and agmatine ureohydrolase); (ii) strain-independent and only dependent on TCDD exposure (e.g. aldehyde dehydrogenase 3A1 and rat selenium-binding protein 2); (iii) dependent on both TCDD exposure and strain (e.g. oxidative stress-related proteins, apoptosis-inducing factor, and MAWD-binding protein). By integrating transcriptomic (microarray) data and genomic data (computational search of regulatory elements), we found that protein expression levels were mainly controlled at the level of transcription. These results reveal, for the first time, a subset of hepatic proteins that are differentially regulated in response to TCDD in a strain-specific manner. Some of these differential responses may play a role in establishing the

Fundamental study of hydrogen-attachment-induced peptide fragmentation occurring in the gas phase and during the matrix-assisted laser desorption/ionization process.

PubMed

Asakawa, Daiki; Takahashi, Hidenori; Iwamoto, Shinichi; Tanaka, Koichi

2018-05-09

Mass spectrometry with hydrogen-radical-mediated fragmentation techniques has been used for the sequencing of proteins/peptides. The two methods, matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) and hydrogen attachment/abstraction dissociation (HAD) are known as hydrogen-radical-mediated fragmentation techniques. MALDI-ISD occurs during laser induced desorption processes, whereas HAD utilizes the association of hydrogen with peptide ions in the gas phase. In this study, the general mechanisms of MALDI-ISD and HAD of peptides were investigated. We demonstrated the fragmentation of four model peptides and investigated the fragment formation pathways using density functional theory (DFT) calculations. The current experimental and computational joint study indicated that MALDI-ISD and HAD produce aminoketyl radical intermediates, which immediately undergo radical-induced cleavage at the N-Cα bond located on the C-terminal side of the radical site, leading to the c'/z˙ fragment pair. In the case of MALDI-ISD, the z˙ fragments undergo a subsequent reaction with the matrix to give z' and matrix adducts of the z fragments. In contrast, the c' and z˙ fragments react with hydrogen atoms during the HAD processes, and various fragment species, such as c˙, c', z˙ and z', were observed in the HAD-MS/MS mass spectra.

Stable Boron Nitride Interphases for Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Morscher, Gregory N.

1999-01-01

Ceramic matrix composites (CMC's) require strong fibers for good toughness and weak interphases so that cracks which are formed in the matrix debond and deflect around the fibers. If the fibers are strongly bonded to the matrix, CMC's behave like monolithic ceramics (e.g., a ceramic coffee cup), and when subjected to mechanical loads that induce cracking, such CMC's fail catastrophically. Since CMC's are being developed for high temperature corrosive environments such as the combustor liner for advanced High Speed Civil Transport aircraft, the interphases need to be able to withstand the environment when the matrix cracks.

Rhubarb Antagonizes Matrix Metalloproteinase-9-induced Vascular Endothelial Permeability

PubMed Central

Cui, Yun-Liang; Zhang, Sheng; Tian, Zhao-Tao; Lin, Zhao-Fen; Chen, De-Chang

2016-01-01

Background: Intact endothelial structure and function are critical for maintaining microcirculatory homeostasis. Dysfunction of the latter is an underlying cause of various organ pathologies. In a previous study, we showed that rhubarb, a traditional Chinese medicine, protected intestinal mucosal microvascular endothelial cells in rats with metastasizing septicemia. In this study, we investigated the effects and mechanisms of rhubarb on matrix metalloproteinase-9 (MMP9)-induced vascular endothelial (VE) permeability. Methods: Rhubarb monomers were extracted and purified by a series of chromatography approaches. The identity of these monomers was analyzed by hydrogen-1 nuclear magnetic resonance (NMR), carbon-13 NMR, and distortionless enhancement by polarization transfer magnetic resonance spectroscopy. We established a human umbilical vein endothelial cell (HUVEC) monolayer on a Transwell insert. We measured the HUVEC permeability, proliferation, and the secretion of VE-cadherin into culture medium using fluorescein isothiocyanate-dextran assay, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, and enzyme-linked immunosorbent assay, respectively, in response to treatment with MMP9 and/or rhubarb monomers. Results: A total of 21 rhubarb monomers were extracted and identified. MMP9 significantly increased the permeability of the HUVEC monolayer, which was significantly reduced by five individual rhubarb monomer (emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl)-β-D-glucose, daucosterol linoleate, and rhein) or a combination of all five monomers (1 μmol/L for each monomer). Mechanistically, the five-monomer mixture at 1 μmol/L promoted HUVEC proliferation. In addition, MMP9 stimulated the secretion of VE-cadherin into the culture medium, which was significantly inhibited by the five-monomer mixture. Conclusions: The rhubarb mixture of emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2

Black rice (Oryza sativa L.) extract modulates ultraviolet-induced expression of matrix metalloproteinases and procollagen in a skin cell model.

PubMed

Han, Mira; Bae, Jung-Soo; Ban, Jae-Jun; Shin, Hee Soon; Lee, Dong Hun; Chung, Jin Ho

2018-05-01

Exposure of the skin to ultraviolet (UV) radiation causes extracellular matrix (ECM) collapse in the dermis, owing to an increase in matrix metalloproteinase (MMP) production in both the epidermis and dermis, and a decrease in type I collagen expression in the dermis. Recently, black rice (Oryza sativa L.) was reported to have a wide range of pharmacological effects in various settings. However, the effects of black rice extract (BRE) on UV‑irradiated skin cells have not yet been characterized. BRE treatment did not affect cell morphology and viability of HaCaT and human dermal fibroblasts (HDF). We demonstrated that BRE downregulated basal and UV‑induced MMP‑1 expression in HaCaT cells. Furthermore, BRE significantly increased type I procollagen expression, and decreased MMP‑1 and MMP‑3 expression in UV‑irradiated HDF. The underlying mechanisms of these results involve a decrease in p38 and c‑Jun N‑terminal kinase activity, and suppression of UV‑induced activation of activator protein‑1 (AP‑1). BRE reduced UV‑induced reactive oxygen species production in HaCaT cells in a dose‑dependent manner. Indeed, mass spectrometry revealed that BRE contained antioxidative flavonoid components such as cyanidin‑3‑O‑β‑D‑glycoside and taxifolin‑7‑O‑glucoside. These findings suggest that BRE attenuates UV‑induced ECM damage by modulating mitogen‑activated protein kinase and AP‑1 signaling, and could be used as an active ingredient for preventing photoaging of the skin.

FEL-FTIR spectroscopy of matrix-isolated formic acid

NASA Astrophysics Data System (ADS)

Henderson, Don O.; Mu, Richard; Silberman, Enrique; Berryman, Kenneth W.; Rella, Chris W.

1994-07-01

Infrared spectral hole burning studies have provided a wealth of information concerning site reorientation of defects in solids and vibrational relaxation dynamics. The most investigated systems appear to be impurities trapped in alkali halides. Limited studies on molecules trapped in noble gas matrices have demonstrated that these systems are good candidates for investigating persistent spectral holes. However, most infrared spectral hole burning studies have been limited by the tunability of commercially available infrared lasers which in turn restricts the spectral feature which can be burned. On the other hand, the tunability of Infrared Free Electron Lasers (IR-FELs) allows for targeting radiation into vibrational of the molecular system under study. We have used the Free Electron Laser-Fourier Transform Infrared Spectroscopy to investigate infrared hole burning of formic acid (HCOOD) isolated in an Ar matrix at a matrix/sample ratio of 4000/1. The results of the FEL radiation tuned to v2 mode of HCOOD are discussed together with matrix induced frequency shifts and matrix induced band splittings.

Photochemical isomerizations of thiosemicarbazide, a matrix isolation study.

PubMed

Rostkowska, Hanna; Lapinski, Leszek; Kozankiewicz, Boleslaw; Nowak, Maciej J

2012-10-11

Two thione conformers of monomeric thiosemicarbazide were trapped from the gas phase into a low-temperature Ar matrix. A phototransformation converting the less stable form of the compound into the most stable conformer was induced by irradiation with near-IR (λ = 1462 nm) or UV (λ > 320 nm) light. This photoeffect allowed separation of the IR spectra of the observed thione forms. The structures of both observed isomers were identified by comparison of the separated experimental IR spectra with the spectra theoretically predicted for two most stable forms of the compound. The population ratio of the two conformers in an Ar matrix, prior to any irradiation, was estimated to be equal ≈2:1. Irradiation of matrix-isolated thiosemicarbazide with shorter-wavelength UV (λ > 270 nm) light induced a phototautomeric reaction generating thiol forms of the compound.

Minocycline attenuates experimental colitis in mice by blocking expression of inducible nitric oxide synthase and matrix metalloproteinases

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

Huang, T.-Y.; Division of Gastroenterology and Hepatology, Tri-Service General Hospital, Taipei, Taiwan; Chu, H.-C.

2009-05-15

In addition to its antimicrobial activity, minocycline exerts anti-inflammatory effects in several disease models. However, whether minocycline affects the pathogenesis of inflammatory bowel disease has not been determined. We investigated the effects of minocycline on experimental colitis and its underlying mechanisms. Acute and chronic colitis were induced in mice by treatment with dextran sulfate sodium (DSS) or trinitrobenzene sulfonic acid (TNBS), and the effect of minocycline on colonic injury was assessed clinically and histologically. Prophylactic and therapeutic treatment of mice with minocycline significantly diminished mortality rate and attenuated the severity of DSS-induced acute colitis. Mechanistically, minocycline administration suppressed inducible nitricmore » oxide synthase (iNOS) expression and nitrotyrosine production, inhibited proinflammatory cytokine expression, repressed the elevated mRNA expression of matrix metalloproteinases (MMPs) 2, 3, 9, and 13, diminished the apoptotic index in colonic tissues, and inhibited nitric oxide production in the serum of mice with DSS-induced acute colitis. In DSS-induced chronic colitis, minocycline treatment also reduced body weight loss, improved colonic histology, and blocked expression of iNOS, proinflammatory cytokines, and MMPs from colonic tissues. Similarly, minocycline could ameliorate the severity of TNBS-induced acute colitis in mice by decreasing mortality rate and inhibiting proinflammatory cytokine expression in colonic tissues. These results demonstrate that minocycline protects mice against DSS- and TNBS-induced colitis, probably via inhibition of iNOS and MMP expression in intestinal tissues. Therefore, minocycline is a potential remedy for human inflammatory bowel diseases.« less

Influence des melanges complexes organiques sur le sort des dioxines et furanes: Implications dans le developpement de facteurs de caracterisation en analyse du cycle de vie

NASA Astrophysics Data System (ADS)

Taing, Eric

The environmental fate of dioxins and furans, or polychlorodibenzo-p-dioxins and -furans (PCDD/Fs), leaching from wood poles treated with pentachlorophenol (PCP) oil is modified by the presence of oil. Interactions between co-contaminants, which also exist for other pollutants within the mixtures, were shown in the specific context of risk analysis, but have never been taken into account for the generic context of life cycle assessment (LCA). This decision-making tool relies on characterization factors (CF) to estimate the potential impacts of an emitted amount of a pollutant in different impact categories such as aquatic ecotoxicity and human toxicity. For these two impact categories, CFs are calculated from a cause-effect chain that models the environmental fate, exposure and effects of the pollutant (represented by a matrix of fate FF, exposure XF and effect EF, respectively), meaning that a modification of PCDD/Fs fate induces a change in PCDD/Fs CFs. The research question is therefore as follows: In life cycle impact assessment (LCIA), to what extent would the potential impacts of PCDD/Fs on aquatic ecotoxicity and human toxicity change when taking into account the influence of a complex organic mixture on PCDD/Fs fate?. Thus, the main objective is to develop CFs of PCDD/Fs when their fate is influenced by PCP oil and compare them with the CFs of PCDD/Fs without oil for the aquatic ecotoxicity and human toxicity impact categories. A mathematic approach is established to determine the new environmental distribution of PCDD/Fs in the presence of oil and a new FF' matrix is calculated from this new distribution to obtain new CFs' integrating oil influence. FF' and CF' are then compared to FF and CF of PCDD/Fs without the oil. Finally, potential (eco)toxic impacts of the PCDD/F Canadian emissions are calculated with the new CFs' of PCDD/Fs in presence of oil. By only focusing on the results for an emission into air, freshwater and natural soil on a continental

Anomalous expansion of Nb nanowires in a NiTi matrix under high pressure

DOE PAGES

Yu, Cun; Ren, Yang; Cui, Lishan; ...

2016-10-17

Under high pressure, materials usually shrink during compression as described by an equation of state. Here, we present the anomalous volume expansion behavior of a one-dimensional Nb nanowire embedded in a NiTi transforming matrix, while the matrix undergoes a pressure-induced martensitic transformation. The Nb volume expansion depends on the NiTi transition pressure range from the matrix, which is controlled by the shear strain induced by different pressure transmitting media. The transformation-induced interfacial stresses between Nb and NiTi may play a major role in this anomaly. In conclusion, our discovery sheds new light on the nano-interfacial effect on mechanical anomalies inmore » heterogeneous systems during a pressure-induced phase transition.« less

Inelastic behaviour of collagen networks in cell–matrix interactions and mechanosensation

PubMed Central

Mohammadi, Hamid; Arora, Pamma D.; Simmons, Craig A.; Janmey, Paul A.; McCulloch, Christopher A.

2015-01-01

The mechanical properties of extracellular matrix proteins strongly influence cell-induced tension in the matrix, which in turn influences cell function. Despite progress on the impact of elastic behaviour of matrix proteins on cell–matrix interactions, little is known about the influence of inelastic behaviour, especially at the large and slow deformations that characterize cell-induced matrix remodelling. We found that collagen matrices exhibit deformation rate-dependent behaviour, which leads to a transition from pronounced elastic behaviour at fast deformations to substantially inelastic behaviour at slow deformations (1 μm min−1, similar to cell-mediated deformation). With slow deformations, the inelastic behaviour of floating gels was sensitive to collagen concentration, whereas attached gels exhibited similar inelastic behaviour independent of collagen concentration. The presence of an underlying rigid support had a similar effect on cell–matrix interactions: cell-induced deformation and remodelling were similar on 1 or 3 mg ml−1 attached collagen gels while deformations were two- to fourfold smaller in floating gels of high compared with low collagen concentration. In cross-linked collagen matrices, which did not exhibit inelastic behaviour, cells did not respond to the presence of the underlying rigid foundation. These data indicate that at the slow rates of collagen compaction generated by fibroblasts, the inelastic responses of collagen gels, which are influenced by collagen concentration and the presence of an underlying rigid foundation, are important determinants of cell–matrix interactions and mechanosensation. PMID:25392399

Infrared Matrix-Isolation Study of New Noble-Gas Compounds

NASA Astrophysics Data System (ADS)

Zhu, Cheng; Räsänen, Markku; Khriachtchev, Leonid

2016-06-01

We identify new noble-gas compounds in solid matrices using IR spectroscopy. The compounds under study belong to two types: HNgY and YNgY' where Ng is a noble-gas atom and Y and Y' are electronegative fragments. The experimental assignments are supported by ab initio calculations at the MP2(full) and CCSD(T) levels of theory with the def2-TZVPPD basis set. We have prepared and characterized two new HNgY compounds (noble-gas hydrides): HKrCCCl in a Kr matrix and HXeCCCl in a Xe matrix.I The synthesis of these compounds includes two steps: UV photolysis of HCCCl in a noble-gas matrix to form the H + CCCl fragments and annealing of the matrix to mobilize H atoms and to promote the H + Ng + CCCl = HNgCCCl reaction. An interesting observation in the experiments on HXeCCCl in a Xe matrix is the temperature-induced transformation of the three H-Xe stretching bands. This observation is explained by temperature-induced changes of local matrix morphology around the embedded HXeCCCl molecule. In these experiments, we have also obtained the IR spectrum of the CCCl radical, which is produced by photodecomposition of HCCCl. We have identified three new YNgY' compounds (fluorinated noble-gas cyanides): FKrCN in a Kr matrix and FXeCN and FXeNC in a Xe matrix.II These molecule are formed by photolysis of FCN in a noble-gas matrix due to locality of this process. The amount of these molecules increases upon thermal mobilization of the F atoms in the photolyzed matrix featuring the F + Ng + CN reaction.

Elasto-plastic analysis of interface layers for fiber reinforced metal matrix composites

NASA Technical Reports Server (NTRS)

Doghri, I.; Leckie, F. A.

1991-01-01

The mismatch in coefficients of thermal expansion (CTE) of fiber and matrix in metal matrix composites reinforced with ceramic fibers induces high thermal stresses in the matrix. Elasto-plastic analyses - with different degrees of simplification and modelization - show that an interface layer with a sufficiently high CTE can reduce the tensile hoop stress in the matrix substantially.

Chronic Exposure to Carbon Nanotubes Induces Invasion of Human Mesothelial Cells through Matrix Metalloproteinase-2

PubMed Central

Lohcharoenkal, Warangkana; Wang, Liying; Stueckle, Todd A.; Dinu, Cerasela Zoica; Castranova, Vincent; Liu, Yuxin; Rojanasakul, Yon

2013-01-01

Malignant mesothelioma is one of the most aggressive forms of cancer known. Recent studies have shown that carbon nanotubes (CNTs) are biopersistent and induce mesothelioma in animals, but the underlying mechanisms are not known. Here, we investigate the effect of long-term exposure to high aspect ratio CNTs on the aggressive behaviors of human pleural mesothelial cells, the primary cellular target of human lung mesothelioma. We show that chronic exposure (4 months) to single- and multi-walled CNTs induced proliferation, migration and invasion of the cells similar to that observed in asbestos-exposed cells. An upregulation of several key genes known to be important in cell invasion, notably matrix metalloproteinase-2 (MMP-2), was observed in the exposed mesothelial cells as determined by real-time PCR. Western blot and enzyme activity assays confirmed the increased expression and activity of MMP-2. Whole genome microarray analysis further indicated the importance of MMP-2 in the invasion gene signaling network of the exposed cells. Knockdown of MMP-2 in CNT and asbestos-exposed cells by shRNA-mediated gene silencing effectively inhibited the aggressive phenotypes. This study demonstrates CNT-induced cell invasion and indicates the role of MMP-2 in the process. PMID:23924264

SLC6A19 is a novel putative gene, induced by dioxins via AhR in human hepatoma HepG2 cells.

PubMed

Tian, Wenjing; Fu, Hualing; Xu, Tuan; Xu, Sherry Li; Guo, Zhiling; Tian, Jijing; Tao, Wuqun; Xie, Heidi Qunhui; Zhao, Bin

2018-06-01

The aryl hydrocarbon receptor (AhR) plays an important role in mediating dioxins toxicity. Currently, genes of P450 families are major research interests in studies on AhR-mediated gene alterations caused by dioxins. Genes related to other metabolic pathways or processes may be also responsive to dioxin exposures. Amino acid transporter B0AT1 (encoded by SLC6A19) plays a decisive role in neutral amino acid transport which is present in kidney, intestine and liver. However, effects of dioxins on its expression are still unknown. In the present study, we focused on the effects of dioxin and dioxin-like compounds on SLC6A19 expression in HepG2 cells. We identified SLC6A19 as a novel putative target gene of AhR activation in HepG2 cells. 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) increased the expression of SLC6A19 in time- and concentration-dependent manners. Using AhR antagonist CH223191 and/or siRNA assays, we demonstrated that certain AhR agonists upregulated SLC6A19 expression via AhR, including TCDD, 1,2,3,7,8-pentachlorodibenzo-p-dioxin (1,2,3,7,8-PeCDD), 2,3,4,7,8- pentachlorodibenzofuran (2,3,4,7,8-PeCDF) and PCB126. In addition, the expression of B0AT1 was also significantly induced by TCDD in HepG2 cells. Our study suggested that dioxins might affect the transcription and translation of SLC6A19 in HepG2 cells, which might be a novel putative gene to assess dioxins' toxicity in amino acid transport and metabolism in liver. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mechanoresponsive, omni-directional and local matrix-degrading actin protrusions in human mesenchymal stem cells microencapsulated in a 3D collagen matrix.

PubMed

Ho, Fu Chak; Zhang, Wei; Li, Yuk Yin; Chan, Barbara Pui

2015-01-01

Cells are known to respond to multiple niche signals including extracellular matrix and mechanical loading. In others and our own studies, mechanical loading has been shown to induce the formation of cell alignment in 3D collagen matrix with random meshwork, challenging our traditional understanding on the necessity of having aligned substrates as the prerequisite of alignment formation. This motivates our adventure in deciphering the mechanism of loading-induced cell alignment and hence the discovery of the novel protrusive functional structure at the cell-matrix interface. Here we report the formation of mechanoresponsive, omni-directional and local matrix-degrading actin protrusions in human mesenchymal stem cells (hMSCs) microencapsulated in collagen following a shifted actin assembly/disassembly balance. These actin protrusive structures exhibit morphological and compositional similarity to filopodia and invadopodia but differ from them in stability, abundance, signaling and function. Without ruling out the possibility that these structures may comprise special subsets of filopodia and invadopodia, we propose to name them as mechanopodia so as to reveal their mechano-inductive mechanism. We also suggest that more intensive investigations are needed to delineate the functional significance and physiological relevance of these structures. This work identifies a brand new target for cell-matrix interaction and mechanoregulation studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Matrix remodeling maintains ESC self-renewal by activating Stat3

PubMed Central

Przybyla, Laralynne M.; Theunissen, Thorold W.; Jaenisch, Rudolf; Voldman, Joel

2013-01-01

While a variety of natural and synthetic matrices have been used to influence embryonic stem cell (ESC) self-renewal or differentiation, and ESCs also deposit a rich matrix of their own, the mechanisms behind how extracellular matrix affects cell fate are largely unexplored. The ESC matrix is continuously remodeled by matrix metalloproteinases (MMPs), a process that we find is enhanced by the presence of mouse embryonic fibroblast feeders in a paracrine manner. Matrix remodeling by MMPs aids in the self-renewal of ESCs, as inhibition of MMPs inhibits the ability of ESCs to self-renew. We also find that addition of the interstitial collagenase MMP1 is sufficient to maintain long-term LIF-independent mESC self-renewal in a dose-dependent manner. This remarkable ability is due to the presence of endogenously produced self-renewal-inducing signals, including the LIF-family ligand CNTF, that are normally trapped within the ECM and become exposed upon MMP-induced matrix remodeling to signal through JAK and Stat3. These results uncover a new role for feeder cells in maintaining self-renewal and show that mESCs normally produce sufficient levels of autocrine-acting pro-self-renewal ligands. PMID:23404867

The Feasibility of Analytic Models for Academic Planning: A Preliminary Analysis of Seven Quarters of Observations on the "Induced Course Load Matrix."

ERIC Educational Resources Information Center

Jewett, Frank I.; And Others

This paper reports on a project undertaken at Humboldt State College, California, to estimate the coefficients of the so-called "induced course load matrix," perhaps the single most vital component of some models that are being developed to aid administrative planning and decisionmaking in institutions of higher education. Chapter I, the…

Reproductive and Developmental Toxicity of Dioxin in Fish1

PubMed Central

King-Heiden, Tisha C.; Mehta, Vatsal; Xiong, Kong M.; Lanham, Kevin A.; Antkiewicz, Dagmara S.; Ganser, Alissa; Heideman, Warren

2011-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD or dioxin) is a global environmental contaminant and the prototypical ligand for investigating aryl hydrocarbon receptor (AHR)-mediated toxicity. Environmental exposure to TCDD results in developmental and reproductive toxicity in fish, birds and mammals. To resolve the ecotoxicological relevance and human health risks posed by exposure to dioxin-like AHR agonists, a vertebrate model is needed that allows for toxicity studies at various levels of biological organization, assesses adverse reproductive and developmental effects and establishes appropriate integrative correlations between different levels of effects. Here we describe the reproductive and developmental toxicity of TCDD in feral fish species and summarize how using the zebrafish model to investigate TCDD toxicity has enabled us to characterize the AHR signaling in fish and to better understand how dioxin-like chemicals induce toxicity. We propose that such studies can be used to predict the risks that AHR ligands pose to feral fish populations and provide a platform for integrating risk assessments for both ecologically relevant organisms and humans. PMID:21958697

Activation of peroxisome proliferator-activated receptor δ inhibits angiotensin II-induced activation of matrix metalloproteinase-2 in vascular smooth muscle cells.

PubMed

Ham, Sun Ah; Lee, Hanna; Hwang, Jung Seok; Kang, Eun Sil; Yoo, Taesik; Paek, Kyung Shin; Do, Jeong Tae; Park, Chankyu; Oh, Jae-Wook; Kim, Jin-Hoi; Han, Chang Woo; Seo, Han Geuk

2014-01-01

We investigated the role of peroxisome proliferator-activated receptor (PPAR) δ on angiotensin (Ang) II-induced activation of matrix metalloproteinase (MMP)-2 in vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand for PPARδ, attenuated Ang II-induced activation of MMP-2 in a concentration-dependent manner. GW501516 also inhibited the generation of reactive oxygen species in VSMCs treated with Ang II. A marked increase in the mRNA levels of tissue inhibitor of metalloproteinase (TIMP)-2 and -3, endogenous antagonists of MMPs, was also observed in GW501516-treated VSMCs. These effects were markedly reduced in the presence of siRNAs against PPARδ, indicating that the effects of GW501516 are PPARδ dependent. Among the protein kinases inhibited by GW501516, suppression of phosphatidylinositol 3-kinase/Akt signaling was shown to have the greatest effect on activation of MMP-2 in VSMCs treated with Ang II. Concomitantly, GW501516-mediated inhibition of MMP-2 activation in VSMCs treated with Ang II was associated with the suppression of cell migration to levels approaching those in cells not exposed to Ang II. Thus, activation of PPARδ confers resistance to Ang II-induced degradation of the extracellular matrix by upregulating expression of its endogenous inhibitor TIMP and thereby modulating cellular responses to Ang II in vascular cells. © 2014 S. Karger AG, Basel.

Inelastic behaviour of collagen networks in cell-matrix interactions and mechanosensation.

PubMed

Mohammadi, Hamid; Arora, Pamma D; Simmons, Craig A; Janmey, Paul A; McCulloch, Christopher A

2015-01-06

The mechanical properties of extracellular matrix proteins strongly influence cell-induced tension in the matrix, which in turn influences cell function. Despite progress on the impact of elastic behaviour of matrix proteins on cell-matrix interactions, little is known about the influence of inelastic behaviour, especially at the large and slow deformations that characterize cell-induced matrix remodelling. We found that collagen matrices exhibit deformation rate-dependent behaviour, which leads to a transition from pronounced elastic behaviour at fast deformations to substantially inelastic behaviour at slow deformations (1 μm min(-1), similar to cell-mediated deformation). With slow deformations, the inelastic behaviour of floating gels was sensitive to collagen concentration, whereas attached gels exhibited similar inelastic behaviour independent of collagen concentration. The presence of an underlying rigid support had a similar effect on cell-matrix interactions: cell-induced deformation and remodelling were similar on 1 or 3 mg ml(-1) attached collagen gels while deformations were two- to fourfold smaller in floating gels of high compared with low collagen concentration. In cross-linked collagen matrices, which did not exhibit inelastic behaviour, cells did not respond to the presence of the underlying rigid foundation. These data indicate that at the slow rates of collagen compaction generated by fibroblasts, the inelastic responses of collagen gels, which are influenced by collagen concentration and the presence of an underlying rigid foundation, are important determinants of cell-matrix interactions and mechanosensation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Regulation of zebrafish CYP3A65 transcription by AHR2

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

Chang, Chin-Teng; Chung, Hsin-Yu; Su, Hsiao-Ting

2013-07-15

CYP3A proteins are the most abundant CYPs in the liver and intestines, and they play a pivotal role in drug metabolism. In mammals, CYP3A genes are induced by various xenobiotics through processes mediated by PXR. We previously identified zebrafish CYP3A65 as a CYP3A ortholog that is constitutively expressed in gastrointestinal tissues, and is upregulated by treatment with dexamethasone, rifampicin or tetrachlorodibenzo-p-dioxin (TCDD). However, the underlying mechanism of TCDD-mediated CYP3A65 transcription is unclear. Here we generated two transgenic zebrafish, Tg(CYP3A65S:EGFP) and Tg(CYP3A65L:EGFP), which contain 2.1 and 5.4 kb 5′ flanking sequences, respectively, of the CYP3A65 gene upstream of EGFP. Both transgenicmore » lines express EGFP in larval gastrointestinal tissues in a pattern similar to that of the endogenous CYP3A65 gene. Moreover, EGFP expression can be significantly induced by TCDD exposure during the larval stage. In addition, EGFP expression can be stimulated by kynurenine, a putative AHR ligand produced during tryptophan metabolism. AHRE elements in the upstream regulatory region of the CYP3A65 gene are indispensible for basal and TCDD-induced transcription. Furthermore, the AHR2 DNA and ligand-binding domains are required to mediate effective CYP3A65 transcription. AHRE sequences are present in the promoters of many teleost CYP3 genes, but not of mammalian CYP3 genes, suggesting that AHR/AHR2-mediated transcription is likely a common regulatory mechanism for teleost CYP3 genes. It may also reflect the different environments that terrestrial and aquatic organisms encounter. - Highlights: • Tg(CYP3A65:EGFP) and CYP3A65 exhibits identical expression pattern. • CYP3A65 can be significantly induced by TCDD or kynurenine. • The AHRE elements are required to mediate CYP3A65 transcription. • The AHR2 DNA and ligand-binding domains are required for CYP3A65 transcription. • AHRE elements are present in many teleost CYP3 genes, but not in

A Candida Biofilm-Induced Pathway for Matrix Glucan Delivery: Implications for Drug Resistance

PubMed Central

Taff, Heather T.; Nett, Jeniel E.; Zarnowski, Robert; Ross, Kelly M.; Sanchez, Hiram; Cain, Mike T.; Hamaker, Jessica; Mitchell, Aaron P.; Andes, David R.

2012-01-01

Extracellular polysaccharides are key constituents of the biofilm matrix of many microorganisms. One critical carbohydrate component of Candida albicans biofilms, β-1,3 glucan, has been linked to biofilm protection from antifungal agents. In this study, we identify three glucan modification enzymes that function to deliver glucan from the cell to the extracellular matrix. These enzymes include two predicted glucan transferases and an exo-glucanase, encoded by BGL2, PHR1, and XOG1, respectively. We show that the enzymes are crucial for both delivery of β-1,3 glucan to the biofilm matrix and for accumulation of mature matrix biomass. The enzymes do not appear to impact cell wall glucan content of biofilm cells, nor are they necessary for filamentation or biofilm formation. We demonstrate that mutants lacking these genes exhibit enhanced susceptibility to the commonly used antifungal, fluconazole, during biofilm growth only. Transcriptional analysis and biofilm phenotypes of strains with multiple mutations suggest that these enzymes act in a complementary fashion to distribute matrix downstream of the primary β-1,3 glucan synthase encoded by FKS1. Furthermore, our observations suggest that this matrix delivery pathway works independently from the C. albicans ZAP1 matrix formation regulatory pathway. These glucan modification enzymes appear to play a biofilm-specific role in mediating the delivery and organization of mature biofilm matrix. We propose that the discovery of inhibitors for these enzymes would provide promising anti-biofilm therapeutics. PMID:22876186

Matrix metalloproteinase inhibitor attenuates cochlear lateral wall damage induced by intratympanic instillation of endotoxin.

PubMed

Choi, Cheol Hee; Jang, Chul Ho; Cho, Yong Bum; Jo, Si Young; Kim, Min Young; Park, Byung Young

2012-04-01

Oxytetracycline and ilomastat are inhibitors of matrix metalloproteinases (MMPs). Their efficacy in protecting against cochlear damage induced by the intratympanic instillation of lipopolysaccharide (LPS), as a means of inducing labyrinthitis, was investigated. Experiments were performed in 21 young male guinea pigs. Intratympanic instillation of LPS was done in the control group (n=7). Intratympanic instillation of oxytetracycline or ilomastat was done after LPS instillation in the experimental group. Measurements of auditory brainstem response (ABR) and cochlear blood flow (CBF) were performed. The organ of Corti was evaluated by field emission scanning electron microscopy (FE-SEM). The blood-labyrinth barrier (BLB) integrity was evaluated with Evans blue uptake. Gelatin zymography was used to assess the expression of active MMP-2 and MMP-9. Ears treated with MMP inhibitors were significantly protected from hearing loss compared to the LPS group. In LPS group, there was a significant decrease of CBF. However, experimental group displayed a statistically significant recovery of CBF. FE-SEM revealed hair cell damage in the LPS-treated group, but hair cells presented a normal appearance in MMP inhibitors. The LPS group showed a marked increase of Evans blue extravasation in the cochlea. However, MMP inhibitors significantly reduced the BLB opening. Active MMP-9 was expressed in the LPS group. Treatment with MMP inhibitors attenuated active MMP-9 expression. The MMP inhibitors oxytetracycline and ilomastat protect from cochlear lateral wall damage caused by LPS-induced labyrinthitis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Evidence-Based Practice: A Matrix for Predicting Phonological Generalization

ERIC Educational Resources Information Center

Gierut, Judith A.; Hulse, Lauren E.

2010-01-01

This paper describes a matrix for clinical use in the selection of phonological treatment targets to induce generalization, and in the identification of probe sounds to monitor during the course of intervention. The matrix appeals to a set of factors that have been shown to promote phonological generalization in the research literature, including…

Effects of CYP1A2 on disposition of 2,3,7, 8-tetrachlorodibenzo-p-dioxin, 2,3,4,7,8-pentachlorodibenzofuran, and 2,2',4,4',5,5'-hexachlorobiphenyl in CYP1A2 knockout and parental (C57BL/6N and 129/Sv) strains of mice.

PubMed

Diliberto, J J; Burgin, D E; Birnbaum, L S

1999-08-15

TCDD is the prototype and most potent member of the highly lipophilic polyhalogenated aromatic hydrocarbons (PHAHs), which are persistent and ubiquitous environmental contaminants. In both acute and subchronic animal studies, there is a specific accumulation of TCDD in liver greater than in adipose tissue. The inducible hepatic binding protein responsible for this hepatic sequestration of TCDD and its congeners has been shown by our laboratory to be CYP1A2 (J. J. Diliberto, D. Burgin, and L. S. Birnbaum, 1997, Biochem. Biophys. Res. Commun. 236, 431-433). The present study was conducted using knockout (KO) mice lacking expression of CYP1A2 (CYP1A2-/-) in order to investigate the role of CYP1A2 gene on the disposition of TCDD, 4-PeCDF (a dioxin-like PHAH), and PCB 153 (a nondioxin-like PCB) in KO (CYP1A2-/-) mice and age-matched parental mice strains (C57BL/6N: CYP1A2+/+, Ah(b/b) and 129/Sv: CYP1A2+/+, Ah(d/d)). Mice were dosed (25 microgram [(3)H]TCDD/kg, 300 microgram [(14)C]4-PeCDF/kg, or 35.8 mg [(14)C]PCB 153/kg bw in a corn oil vehicle) orally and terminated after 4 days. Residues of administered compounds in collected tissues and daily excreta were quantitated using (3)H or (14)C activity. Results demonstrated differential effects in disposition for the various treatments within the three genetically different groups of mice. In KO mice, TCDD, 4-PeCDF, and PCB 153 had very little hepatic localization of chemical, and the major depot was adipose tissue. In contrast, parental strains demonstrated hepatic sequestration of TCDD and 4-PeCDF, whereas disposition of PCB 153 in parental strains was similar to that in KO mice. Another difference between KO mice and parental strains was the enhanced urinary excretion of 4-PeCDF. This study demonstrates the importance of CYP1A2 in pharmacokinetic behavior and mechanistic issues for TCDD and related compounds. Copyright 1999 Academic Press.

Extracellular matrix metalloproteinase inducer expression in the baboon endometrium: menstrual cycle and endometriosis

PubMed Central

Braundmeier, A G; Fazleabas, A T; Nowak, R A

2016-01-01

Extracellular matrix metalloproteinase inducer (EMMPRIN; BSG) regulates tissue remodeling through matrix metalloproteinases (MMPs). In human and non-human primates, endometrial remodeling is important for menstruation and the pathogenesis of endometriosis. We hypothesized that as in humans, BSG and MMPs are expressed in the endometrium of cycling baboons, and their expression is hormonally regulated by ovarian hormones, but endometriosis disrupts this regulation. BSG expression was evaluated in the baboon endometrium by q-PCR and immunohistochemistry. In the endometrium of control cycling animals, BSG mRNA levels were highest in late secretory stage tissue. BSG protein localized to glandular epithelial cells during the proliferative phase; whereas, secretory stage tissues expressed BSG in glandular and luminal epithelia with weak stromal staining. Several MMPs were differentially expressed throughout the menstrual cycle with the highest levels found during menstruation. In ovariectomized animals, BSG endometrial mRNA levels were highest with treatment of both estrogen and progesterone than that with only estrogen. Estrogen alone resulted in BSG protein localization primarily in the endometrial glandular epithelia, while estrogen and progesterone treatment displayed BSG protein localization in both the glandular and stromal cells. Exogenous hormone treatment resulted in differential expression patterns of all MMPs compared with the control cycling animals. In the eutopic endometrium of endometriotic animals, BSG mRNA levels and protein were elevated early but decreased later in disease progression. Endometriosis elevated the expression of all MMPs except MMP7 compared with the control animals. In baboons, BSG and MMP endometrial expression is regulated by both ovarian hormones, and their expression patterns are dysregulated in endometriotic animals. PMID:20841363

Toxicity of Polychlorinated Diphenyl Ethers in Hydra Attenuata and in Rat Whole Embryo Culture

DTIC Science & Technology

1991-05-01

shown that 2,3,7,8-tetrachlorodibenzo- p-dioxin (2,3,7,8-TCDD) is a potent inducer of cleft palate and hydronephrosis in mice (Poland and Glover, 1980...predominant malformations detected with 3,3’,4,4",5,5’-hexachlorobi- phenyl were cleft palate and hydronephrosis (Marks et al., 1981). Oral... hydronephrosis in mice (Poland and Glover, 1980), although differences in sensitivity of mice to 2,3,7,8-TCDD have been identified. C57BL,/6J mice are a

Developmental exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin alters DNA methyltransferase (dnmt) expression in zebrafish (Danio rerio)

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

Aluru, Neelakanteswar, E-mail: naluru@whoi.edu; Kuo, Elaine; Stanford University, 450 Serra Mall, Stanford, CA 94305

2015-04-15

DNA methylation is one of the most important epigenetic modifications involved in the regulation of gene expression. The DNA methylation reaction is catalyzed by DNA methyltransferases (DNMTs). Recent studies have demonstrated that toxicants can affect normal development by altering DNA methylation patterns, but the mechanisms of action are poorly understood. Hence, we tested the hypothesis that developmental exposure to TCDD affects dnmt gene expression patterns. Zebrafish embryos were exposed to 5 nM TCDD for 1 h from 4 to 5 h post-fertilization (hpf) and sampled at 12, 24, 48, 72, and 96 hpf to determine dnmt gene expression and DNAmore » methylation patterns. We performed a detailed analysis of zebrafish dnmt gene expression during development and in adult tissues. Our results demonstrate that dnmt3b genes are highly expressed in early stages of development, and dnmt3a genes are more abundant in later stages. TCDD exposure upregulated dnmt1 and dnmt3b2 expression, whereas dnmt3a1, 3b1, and 3b4 are downregulated following exposure. We did not observe any TCDD-induced differences in global methylation or hydroxymethylation levels, but the promoter methylation of aryl hydrocarbon receptor (AHR) target genes was altered. In TCDD-exposed embryos, AHR repressor a (ahrra) and c-fos promoters were differentially methylated. To characterize the TCDD effects on DNMTs, we cloned the dnmt promoters with xenobiotic response elements and conducted AHR transactivation assays using a luciferase reporter system. Our results suggest that ahr2 can regulate dnmt3a1, dnmt3a2, and dnmt3b2 expression. Overall, we demonstrate that developmental exposure to TCDD alters dnmt expression and DNA methylation patterns. - Highlights: • TCDD altered the dnmt expression in a gene and developmental time-specific manner. • TCDD hypermethylated ahrra and hypomethylated c-fos proximal promoter regions. • Functional analysis suggests that ahr2 can regulate dnmt3a1, 3a2, and 3b2 expression

Low molecular-weight gel fraction of Aloe vera exhibits gastroprotection by inducing matrix metalloproteinase-9 inhibitory activity in alcohol-induced acute gastric lesion tissues.

PubMed

Park, Chul-Hong; Son, Hyeong-U; Yoo, Chi-Yeol; Lee, Sang-Han

2017-12-01

Aloe has been used for the prevention and cure of various diseases and symptoms including burns, injuries, oedema and pain. This study determines the specific inhibitory activity of matrix metalloproteinase (MMP)-9 induced by the low molecular-weight gel fraction of Aloe vera (L.) Burm.f. (lgfAv) on alcohol-induced acute gastric lesions. We examined the protective effects of oral (p.o.) administration of lgfAv (molecular weight cutoff <50.0 kDa, 150.0 mg/kg body weight) in a Balb/c mouse model of alcohol-induced acute gastritis for 1 h exposure. By measuring ulcer index, we compared the antiulcerative activity of the fraction. mRNA expression and immunohistochemical analysis of various biomarkers were performed. The lgfAv-treated mice exhibited drastically fewer ulcer lesions than the untreated control mice did. It featured that lgfAv lessened the ulcer lesions than their relevant controls. Moreover, the transcriptional level of MMP-9 was completely alleviated by lgfAv treatment in alcohol-treated gastritis-induced mice. The transcriptional level of MMP-9 was significantly alleviated by lgfAv treatment of the model. However, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry experiments revealed that lgfAv treatment in mucosal tissues had the potential to inhibit the mRNA and protein expression levels of MMP-9, respectively. The protein expression of MMP-9 was closely associated with lgfAv-induced gastroprotection against alcohol-induced gastric lesions. The present findings suggest that lgfAv has the potential to alleviate alcohol-induced acute gastric lesions, which is mediated in part, mainly by the suppression of the mRNA expression of MMP-9.

Investigation of the Matrix Effect on the Accuracy of Quantitative Analysis of Trace Metals in Liquids Using Laser-Induced Breakdown Spectroscopy with Solid Substrates.

PubMed

Xiu, Junshan; Dong, Lili; Qin, Hua; Liu, Yunyan; Yu, Jin

2016-12-01

The detection limit of trace metals in liquids has been improved greatly by laser-induced breakdown spectroscopy (LIBS) using solid substrate. A paper substrate and a metallic substrate were used as a solid substrate for the detection of trace metals in aqueous solutions and viscous liquids (lubricating oils) respectively. The matrix effect on quantitative analysis of trace metals in two types of liquids was investigated. For trace metals in aqueous solutions using paper substrate, the calibration curves established for pure solutions and mixed solutions samples presented large variation on both the slope and the intercept for the Cu, Cd, and Cr. The matrix effects among the different elements in mixed solutions were observed. However, good agreement was obtained between the measured and known values in real wastewater. For trace metals in lubricating oils, the matrix effect between the different oils is relatively small and reasonably negligible under the conditions of our experiment. A universal calibration curve can be established for trace metals in different types of oils. The two approaches are verified that it is possible to develop a feasible and sensitive method with accuracy results for rapid detection of trace metals in industrial wastewater and viscous liquids by laser-induced breakdown spectroscopy. © The Author(s) 2016.

Cell–material interactions on biphasic polyurethane matrix

PubMed Central

Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

2013-01-01

Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

Adaptive changes in global gene expression profile of lung carcinoma A549 cells acutely exposed to distinct types of AhR ligands.

PubMed

Procházková, Jiřina; Strapáčová, Simona; Svržková, Lucie; Andrysík, Zdeněk; Hýžďalová, Martina; Hrubá, Eva; Pěnčíková, Kateřina; Líbalová, Helena; Topinka, Jan; Kléma, Jiří; Espinosa, Joaquín M; Vondráček, Jan; Machala, Miroslav

2018-08-01

Exposure to persistent ligands of aryl hydrocarbon receptor (AhR) has been found to cause lung cancer in experimental animals, and lung adenocarcinomas are often associated with enhanced AhR expression and aberrant AhR activation. In order to better understand the action of toxic AhR ligands in lung epithelial cells, we performed global gene expression profiling and analyze TCDD-induced changes in A549 transcriptome, both sensitive and non-sensitive to CH223191 co-treatment. Comparison of our data with results from previously reported microarray and ChIP-seq experiments enabled us to identify candidate genes, which expression status reflects exposure of lung cancer cells to TCDD, and to predict processes, pathways (e.g. ER stress, Wnt/β-cat, IFNɣ, EGFR/Erbb1), putative TFs (e.g. STAT, AP1, E2F1, TCF4), which may be implicated in adaptive response of lung cells to TCDD-induced AhR activation. Importantly, TCDD-like expression fingerprint of selected genes was observed also in A549 cells exposed acutely to both toxic (benzo[a]pyrene, benzo[k]fluoranthene) and endogenous AhR ligands (2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid methyl ester and 6-formylindolo[3,2-b]carbazole). Overall, our results suggest novel cellular candidates, which could help to improve monitoring of AhR-dependent transcriptional activity during acute exposure of lung cells to distinct types of environmental pollutants. Copyright © 2018 Elsevier B.V. All rights reserved.

Doxycycline and HIV Infection Suppress Tuberculosis-induced Matrix Metalloproteinases

PubMed Central

Walker, Naomi F.; Clark, Simon O.; Oni, Tolu; Andreu, Nuria; Tezera, Liku; Singh, Shivani; Saraiva, Luísa; Pedersen, Bernadette; Kelly, Dominic L.; Tree, Julia A.; D'Armiento, Jeanine M.; Meintjes, Graeme; Mauri, Francesco A.; Williams, Ann; Wilkinson, Robert J.; Friedland, Jon S.

2012-01-01

Rationale: Tuberculosis kills more than 1.5 million people per year, and standard treatment has remained unchanged for more than 30 years. Tuberculosis (TB) drives matrix metalloproteinase (MMP) activity to cause immunopathology. In advanced HIV infection, tissue destruction is reduced, but underlying mechanisms are poorly defined and no current antituberculous therapy reduces host tissue damage. Objectives: To investigate MMP activity in patients with TB with and without HIV coinfection and to determine the potential of doxycycline to inhibit MMPs and decrease pathology. Methods: Concentrations of MMPs and cytokines were analyzed by Luminex array in a prospectively recruited cohort of patients. Modulation of MMP secretion and Mycobacterium tuberculosis growth by doxycycline was studied in primary human cells and TB-infected guinea pigs. Measurements and Main Results: HIV coinfection decreased MMP concentrations in induced sputum of patients with TB. MMPs correlated with clinical markers of tissue damage, further implicating dysregulated protease activity in TB-driven pathology. In contrast, cytokine concentrations were no different. Doxycycline, a licensed MMP inhibitor, suppressed TB-dependent MMP-1 and -9 secretion from primary human macrophages and epithelial cells by inhibiting promoter activation. In the guinea pig model, doxycycline reduced lung TB colony forming units after 8 weeks in a dose-dependent manner compared with untreated animals, and in vitro doxycycline inhibited mycobacterial proliferation. Conclusions: HIV coinfection in patients with TB reduces concentrations of immunopathogenic MMPs. Doxycycline decreases MMP activity in a cellular model and suppresses mycobacterial growth in vitro and in guinea pigs. Adjunctive doxycycline therapy may reduce morbidity and mortality in TB. PMID:22345579

Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines.

PubMed

Vorrink, Sabine U; Severson, Paul L; Kulak, Mikhail V; Futscher, Bernard W; Domann, Frederick E

2014-02-01

The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degrees of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB 126). Exposure to 1% O2 prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity. Copyright © 2013 Elsevier Inc. All rights reserved.

Structure-function relationship of avian eggshell matrix proteins: a comparative study of two major eggshell matrix proteins, ansocalcin and OC-17.

PubMed

Lakshminarayanan, Rajamani; Joseph, Jeremiah S; Kini, R Manjunatha; Valiyaveettil, Suresh

2005-01-01

The role of individual matrix proteins in avian eggshell calcification is poorly understood despite numerous attempts to characterize and localize their presence in the eggshell matrix. Ansocalcin, the major matrix protein from goose eggshell, was found to induce the formation of calcite crystal aggregates under in vitro. Owing to its high similarity with the chicken eggshell matrix protein ovocleidin 17 (OC-17), a comparative investigation has been carried out to understand the structure-function relationship. RP-HPLC shows that ansocalcin is the major component in extracts of goose eggshells before and after bleach treatment. However, OC-17 was observed in minute quantities in the extract of bleach-treated chicken eggshells. In vitro crystal growth experiments showed that OC-17 and ansocalcin interact differently with the calcite crystals formed. Circular dichroism, intrinsic tryptophan fluorescence, and dynamic light scattering studies showed that, under the conditions used in our experiments, OC-17 does not aggregate in solution or induce the nucleation of calcite aggregates in the concentration range used. These observations indicate that OC-17 and ansocalcin play different roles in the eggshell calcification. To our knowledge, this is the first report on the comparison of properties of homologous eggshell proteins that belong to the same phylogeny.

Mitochondrial unfolded protein response controls matrix pre-RNA processing and translation.

PubMed

Münch, Christian; Harper, J Wade

2016-06-30

The mitochondrial matrix is unique in that it must integrate the folding and assembly of proteins derived from the nuclear and mitochondrial genomes. In Caenorhabditis elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial-matrix-localized ornithine transcarbamylase induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 (ref. 8) or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response encompasses widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing caused by transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3 (ref. 10). This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt.

DFT study of the adsorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin on pristine and Ni-doped boron nitride nanotubes.

PubMed

Wang, Ruoxi; Zhang, Dongju; Liu, Chengbu

2017-02-01

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are highly toxic to humans and the environment. Developing efficient methods to detect or remove these pollutants is particularly important and urgent. Boron nitride nanotubes (BNNTs) with low dimension and high surface-to-volume ratio might be one of promising materials for the adsorption of PCDD/Fs. Here we present a density functional theory (DFT) study on the interaction of the pristine and Ni doped (8,0) single-walled BNNTs with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener among PCDD/F family. The calculated results show that the pristine BNNT intrinsically interacts with TCDD via physisorption with π-π stacking interaction, in contrast, the Ni-doped BNNT presents much higher reactivities toward TCDD. The impurity Ni atom plays a crucial role for capturing TCDD molecule. We also find that the Ni doping introduces the local electronic states within the band gap of the BNNT and induces magnetism in the doped systems. The present results are expected to provide useful guidance for the potential application of BNNTs as adsorption materials for detecting or removing dioxin pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Extracellular matrix remodeling and matrix metalloproteinase inhibition in visceral adipose during weight cycling in mice.

PubMed

Caria, Cíntia Rabelo E Paiva; Gotardo, Érica Martins Ferreira; Santos, Paola Souza; Acedo, Simone Coghetto; de Morais, Thainá Rodrigues; Ribeiro, Marcelo Lima; Gambero, Alessandra

2017-10-15

Extracellular matrix (ECM) remodeling is necessary for a health adipose tissue (AT) expansion and also has a role during weight loss. We investigate the ECM alteration during weight cycling (WC) in mice and the role of matrix metalloproteinases (MMPs) was assessed using GM6001, an MMP inhibitor, during weight loss (WL). Obesity was induced in mice by a high-fat diet. Obese mice were subject to caloric restriction for WL followed by reintroduction to high-fat diet for weight regain (WR), resulting in a WC protocol. In addition, mice were treated with GM6001 during WL period and the effects were observed after WR. Activity and expression of MMPs was intense during WL. MMP inhibition during WL results in inflammation and collagen content reduction. MMP inhibition during WL period interferes with the period of subsequent expansion of AT resulting in improvements in local inflammation and systemic metabolic alterations induced by obesity. Our results suggest that MMPs inhibition could be an interesting target to improve adipose tissue inflammation during WL and to support weight cyclers. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of novel lysosomal matrix proteins by proteome analysis.

PubMed

Kollmann, Katrin; Mutenda, Kudzai E; Balleininger, Martina; Eckermann, Ellen; von Figura, Kurt; Schmidt, Bernhard; Lübke, Torben

2005-10-01

The lysosomal matrix is estimated to contain about 50 different proteins. Most of the matrix proteins are acid hydrolases that depend on mannose 6-phosphate receptors (MPR) for targeting to lysosomes. Here, we describe a comprehensive proteome analysis of MPR-binding proteins from mouse. Mouse embryonic fibroblasts defective in both MPR (MPR 46-/- and MPR 300-/-) are known to secrete the lysosomal matrix proteins. Secretions of these cells were affinity purified using an affinity matrix derivatized with MPR46 and MPR300. In the protein fraction bound to the affinity matrix and eluted with mannose 6-phosphate, 34 known lysosomal matrix proteins, 4 candidate proteins of the lysosomal matrix and 4 non-lysosomal contaminants were identified by mass spectrometry after separation by two-dimensional gel electrophoresis or by multidimensional protein identification technology. For 3 of the candidate proteins, mammalian ependymin-related protein-2 (MERP-2), retinoid-inducible serine carboxypeptidase (RISC) and the hypothetical 66.3-kDa protein we could verify that C-terminally tagged forms bound in an M6P-dependent manner to an MPR-affinity matrix and were internalized via MPR-mediated endocytosis. Hence these 3 proteins are likely to represent hitherto unrecognized lysosomal matrix proteins.

Effects of 3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected cormorant eggs injected into double-crested cormorant (Phalacrocorax auritus) eggs

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

Powell, D.C.; Aulerich, R.J.; Powell, J.F.

1997-07-01

Double-crested cormorant (Phalacrocorax auritus) eggs were injected with either 3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected double-crested cormorant eggs. These compounds were injected into the yolks of cormorant eggs from an isolated colony on Lake Winnipegosis, Manitoba, Canada. Upon hatching, chicks were necropsied. The brain, bursa, heart, liver, and spleen were removed and weighed. An approximate median lethal dose (LD50) of 158 {micro}g/kg egg was determined for PCB 126, which is 69 times greater than the LD50 determined for the chicken (Gallus domesticus) in a previous study. A significantly greater mortality occurred at the highest dosemore » of TCDD when compared to the vehicle control. However, the mortality data did not provide sufficient information for the determination of an LD50. The cormorant egg extract did not adversely affect hatchability. No significant increases were observed in the incidence of developmental abnormalities, including pronounced edema, in any of the treatment groups, nor were there any relevant effects on body and organ weights. Based on the results from this study, the cormorant appears to be considerably less sensitive to polyhalogenated diaromatic hydrocarbons than the chicken, which has been the typical species used for egg injection studies.« less

Effects of 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected cormorant eggs injected into double-crested cormorant (Phalacrocorax auritus) eggs

USGS Publications Warehouse

Powell, Debra C.; Aulerich, Richard J.; Meadows, John C.; Tillitt, Donald E.; Powell, Jon F.; Restum, Janelle C.; Stromborg, Kenneth L.; Giesy, John P.; Bursian, Steven J.

1997-01-01

Double-crested cormorant (Phalacrocorax auritus) eggs were injected with either 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), or an extract derived from field-collected double-crested cormorant eggs. These compounds were injected into the yolks of cormorant eggs from an isolated colony on Lake Winnipegosis, Manitoba, Canada. Upon hatching, chicks were necropsied. The brain, bursa, heart, liver, and spleen were removed and weighed. An approximate median lethal dose (LD50) of 158 μg/kg egg was determined for PCB 126, which is 69 times greater than the LD50 determined for the chicken (Gallus domesticus) in a previous study. A significantly greater mortality occurred at the highest dose of TCDD (4.0 μg/kg egg) when compared to the vehicle control. However, the mortality data did not provide sufficient information for the determination of an LD50. The cormorant egg extract did not adversely affect hatchability. No significant increases were observed in the incidence of developmental abnormalities, including pronounced edema, in any of the treatment groups, nor were there any relevant effects on body and organ weights. Based on the results from this study, the cormorant appears to be considerably less sensitive to polyhalogenated diaromatic hydrocarbons than the chicken, which has been the typical species used for egg injection studies.

Regulation of proximal tubular cell differentiation and proliferation in primary culture by matrix stiffness and ECM components.

PubMed

Chen, Wan-Chun; Lin, Hsi-Hui; Tang, Ming-Jer

2014-09-15

To explore whether matrix stiffness affects cell differentiation, proliferation, and transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) in primary cultures of mouse proximal tubular epithelial cells (mPTECs), we used a soft matrix made from monomeric collagen type I-coated polyacrylamide gel or matrigel (MG). Both kinds of soft matrix benefited primary mPTECs to retain tubular-like morphology with differentiation and growth arrest and to evade TGF-β1-induced EMT. However, the potent effect of MG on mPTEC differentiation was suppressed by glutaraldehyde-induced cross-linking and subsequently stiffening MG or by an increasing ratio of collagen in the soft mixed gel. Culture media supplemented with MG also helped mPTECs to retain tubular-like morphology and a differentiated phenotype on stiff culture dishes as soft MG did. We further found that the protein level and activity of ERK were scaled with the matrix stiffness. U-0126, a MEK inhibitor, abolished the stiff matrix-induced dedifferentiation and proliferation. These data suggest that the ERK signaling pathway plays a vital role in matrix stiffness-regulated cell growth and differentiation. Taken together, both compliant property and specific MG signals from the matrix are required for the regulation of epithelial differentiation and proliferation. This study provides a basic understanding of how physical and chemical cues derived from the extracellular matrix regulate the physiological function of proximal tubules and the pathological development of renal fibrosis. Copyright © 2014 the American Physiological Society.

Extracellular Matrix from Periodontal Ligament Cells Could Induce the Differentiation of Induced Pluripotent Stem Cells to Periodontal Ligament Stem Cell-Like Cells.

PubMed

Hamano, Sayuri; Tomokiyo, Atsushi; Hasegawa, Daigaku; Yoshida, Shinichiro; Sugii, Hideki; Mitarai, Hiromi; Fujino, Shoko; Wada, Naohisa; Maeda, Hidefumi

2018-01-15

The periodontal ligament (PDL) plays an important role in anchoring teeth in the bone socket. Damage to the PDL, such as after severe inflammation, can be treated with a therapeutic strategy that uses stem cells derived from PDL tissue (PDLSCs), a strategy that has received intense scrutiny over the past decade. However, there is an insufficient number of PDLSCs within the PDL for treating such damage. Therefore, we sought to induce the differentiation of induced pluripotent stem (iPS) cells into PDLSCs as an initial step toward PDL therapy. To this end, we first induced iPS cells into neural crest (NC)-like cells. We then captured the p75 neurotrophic receptor-positive cells (iPS-NC cells) and cultured them on an extracellular matrix (ECM) produced by human PDL cells (iPS-NC-PDL cells). These iPS-NC-PDL cells showed reduced expression of embryonic stem cell and NC cell markers as compared with iPS and iPS-NC cells, and enrichment of mesenchymal stem cell markers. The cells also had a higher proliferative capacity, multipotency, and elevated expression of PDL-related markers than iPS-NC cells cultured on fibronectin and laminin (iPS-NC-FL cells) or ECM produced by human skin fibroblast cells (iPS-NC-SF cells). Overall, we present a culture method to produce high number of PDLSC-like cells from iPS cells as a first step toward a strategy for PDL regeneration.

Generation of Tg(cyp1a:gfp) Transgenic Zebrafish for Development of a Convenient and Sensitive In Vivo Assay for Aryl Hydrocarbon Receptor Activity.

PubMed

Xu, Hongyan; Li, Caixia; Li, Yan; Ng, Grace Hwee Boon; Liu, Chunsheng; Zhang, Xiaoyan; Gong, Zhiyuan

2015-12-01

Both dioxins/dioxin-like compounds and polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants and cause multiple adverse health effects on human and wildlife. Cyp1a is the most commonly used biomarker induced by these pollutants through activation of the aryl hydrocarbon receptor (AhR) pathway. Here we generated Tg(cyp1a:gfp) transgenic zebrafish for establishing a convenient in vivo assay for analysing these xenobiotic compounds. The Tg(cyp1a:gfp) larvae at 4 day post-fertilization were tested with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and GFP induction was observed mainly in the kidney, liver and gut. Similar GFP expression was also induced strongly by two dioxin-like chemicals, co-planar polychlorinated biphenyl (PCB126) and polychlorinated dibenzo-p-furan (PeCDF) and relatively weakly by two PAHs, 3-methylcholanthrene (3-MC) and benzo[a]pyrene (BAP). The lowest observed effective concentration (LOEC) of TCDD was estimated to be ∼1 pM and the EC50 (effective concentration to induce GFP in 50 % of Tg(cyp1a:gfp) larvae) was ∼10 pM. PCB126 and PeCDF had ∼10× lower potencies in GFP induction than TCDD, while the potencies for 3-MC and BAP were at least 1000× lower. The sensitivity of Tg(cyp1a:gfp) larvae to respond TCDD was also favourable compared to that of ethoxyresorufin-O-deethylase (EROD) assay in both zebrafish larvae and adult livers. As GFP-based assay in transgenic zebrafish can be easily accommodated in multi-well dishes, the Tg(cyp1a:gfp) zebrafish should provide not only a valuable biomonitoring tool for aquatic contaminants but also a potential high-throughput chemical screening platform for identification of new AhR agonists.

Charge retention characteristics of silicide-induced crystallized polycrystalline silicon floating gate thin-film transistors for active matrix organic light-emitting diode.

PubMed

Park, Jae Hyo; Son, Se Wan; Byun, Chang Woo; Kim, Hyung Yoon; Joo, So Na; Lee, Yong Woo; Yun, Seung Jae; Joo, Seung Ki

2013-10-01

In this work, non-volatile memory thin-film transistor (NVM-TFT) was fabricated by nickel silicide-induced laterally crystallized (SILC) polycrystalline silicon (poly-Si) as the active layer. The nickel seed silicide-induced crystallized (SIC) poly-Si was used as storage layer which is embedded in the gate insulator. The novel unit pixel of active matrix organic light-emitting diode (AMOLED) using NVM-TFT is proposed and investigated the electrical and optical performance. The threshold voltage shift showed 17.2 V and the high reliability of retention characteristic was demonstrated until 10 years. The retention time can modulate the recharge refresh time of the unit pixel of AMOLED up to 5000 sec.

Analysis of delamination in cross ply laminates initiating from impact induced matrix cracking

NASA Technical Reports Server (NTRS)

Salpekar, S. A.

1991-01-01

Several two dimensional finite element analyses of (0 sub 2/90 sub 8/0 sub 2) glass/epoxy and graphite-epoxy composite laminates were performed to study some of the characteristics of damage development due to an impact load. A cross section through the thickness of the laminate with fixed ends, and carrying a transverse load in the center was analyzed. Inclined matrix cracks such as those produced by low velocity impact were modeled in the 90 deg ply group. The introduction of the matrix cracks caused large interlaminar tension and shear stresses in the vicinity of both crack tips in the 0/90 and 90/0 interfaces. The large interlaminar stresses at the ends of the matrix cracks indicate that matrix cracking may give rise to delamination. The ratio of mode I to total strain energy release rate at the beginning of delamination calculated at the two matrix crack tips was 60 and 28 pct., respectively, in the glass/epoxy laminate. The corresponding ratio was 97 and 77 pct. in the graphite-epoxy laminate. Thus, a significant mode I component of strain energy release rate may be present at the delamination initiation due to an impact load.

Protective effects of levamisole, acetylsalicylic acid, and α-tocopherol against dioxin toxicity measured as the expression of AhR and COX-2 in a chicken embryo model.

PubMed

Gostomska-Pampuch, Kinga; Ostrowska, Alicja; Kuropka, Piotr; Dobrzyński, Maciej; Ziółkowski, Piotr; Kowalczyk, Artur; Łukaszewicz, Ewa; Gamian, Andrzej; Całkosiński, Ireneusz

2017-04-01

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are classed as persistent organic pollutants and have adverse effects on multiple functions within the body. Dioxins are known carcinogens, immunotoxins, and teratogens. Dioxins are transformed in vivo, and interactions between the products and the aryl hydrocarbon receptor (AhR) lead to the formation of proinflammatory and toxic metabolites. The aim of this study was to determine whether α-tocopherol (vitamin E), acetylsalicylic acid (ASA), and levamisole can decrease the amount of damage caused by dioxins. Fertile Hubbard Flex commercial line chicken eggs were injected with solutions containing 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or containing TCDD and the test compounds. The chicken embryos and organs were analyzed after 7 and 13 days. The levels at which AhR and cyclooxygenase-2 (COX-2) proteins (which are induced during inflammation) were expressed were evaluated by performing immunohistochemical analyses on embryos treated with TCDD alone or with TCDD and the test compounds. TCDD caused developmental disorders and increased AhR and COX-2 expression in the chicken embryo tissues. Vitamin E, levamisole, ASA, and ASA plus vitamin E inhibited AhR and COX-2 expression in embryos after 7 days and decreased AhR and COX-2 expression in embryos after 13 days. ASA, levamisole, and ASA plus vitamin E weakened the immune response and prevented multiple organ changes. Vitamin E was not fully protective against developmental changes in the embryos.

Pairing matrix elements and pairing gaps with bare, effective, and induced interactions

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

Barranco, F.; Bortignon, P.F.; Colo, G.

2005-11-01

The dependence on the single-particle states of the pairing matrix elements of the Gogny force and of the bare low-momentum nucleon-nucleon potential v{sub low-k}--designed so as to reproduce the low-energy observables avoiding the use of a repulsive core--is studied for a typical finite, superfluid nucleus ({sup 120}Sn). It is found that the matrix elements of v{sub low-k} follow closely those of v{sub Gogny} on a wide range of energy values around the Fermi energy e{sub F}, those associated with v{sub low-k} being less attractive. This result explains the fact that around e{sub F} the pairing gap {delta}{sub Gogny} associated withmore » the Gogny interaction (and with a density of single-particle levels corresponding to an effective k mass m{sub k}{approx_equal}0.7 m) is a factor of about 2 larger than {delta}{sub low-k}, being in agreement with {delta}{sub exp}=1.4 MeV. The exchange of low-lying collective surface vibrations among pairs of nucleons moving in time-reversal states gives rise to an induced pairing interaction v{sub ind} peaked at e{sub F}. The interaction (v{sub low-k}+v{sub ind}) Z{sub {omega}} arising from the renormalization of the bare nucleon-nucleon potential and of the single-particle motion ({omega}-mass and quasiparticle strength Z{sub {omega}}) associated with the particle-vibration coupling mechanism, leads to a value of the pairing gap at the Fermi energy {delta}{sub ren} that accounts for the experimental value. An important question that remains to be studied quantitatively is to what extent {delta}{sub Gogny}, which depends on average parameters, and {delta}{sub ren}, which explicitly depends on the parameters describing the (low-energy) nuclear structure, display or not a similar isotopic dependence and whether this dependence is borne out by the data.« less

An intracellular matrix metalloproteinase-2 isoform induces tubular regulated necrosis: implications for acute kidney injury.

PubMed

Ceron, Carla S; Baligand, Celine; Joshi, Sunil; Wanga, Shaynah; Cowley, Patrick M; Walker, Joy P; Song, Sang Heon; Mahimkar, Rajeev; Baker, Anthony J; Raffai, Robert L; Wang, Zhen J; Lovett, David H

2017-06-01

Acute kidney injury (AKI) causes severe morbidity, mortality, and chronic kidney disease (CKD). Mortality is particularly marked in the elderly and with preexisting CKD. Oxidative stress is a common theme in models of AKI induced by ischemia-reperfusion (I-R) injury. We recently characterized an intracellular isoform of matrix metalloproteinase-2 (MMP-2) induced by oxidative stress-mediated activation of an alternate promoter in the first intron of the MMP-2 gene. This generates an NH 2 -terminal truncated MMP-2 (NTT-MMP-2) isoform that is intracellular and associated with mitochondria. The NTT-MMP-2 isoform is expressed in kidneys of 14-mo-old mice and in a mouse model of coronary atherosclerosis and heart failure with CKD. We recently determined that NTT-MMP-2 is induced in human renal transplants with delayed graft function and correlated with tubular cell necrosis. To determine mechanism(s) of action, we generated proximal tubule cell-specific NTT-MMP-2 transgenic mice. Although morphologically normal at the light microscopic level at 4 mo, ultrastructural studies revealed foci of tubular epithelial cell necrosis, the mitochondrial permeability transition, and mitophagy. To determine whether NTT-MMP-2 expression enhances sensitivity to I-R injury, we performed unilateral I-R to induce mild tubular injury in wild-type mice. In contrast, expression of the NTT-MMP-2 isoform resulted in a dramatic increase in tubular cell necrosis, inflammation, and fibrosis. NTT-MMP-2 mice had enhanced expression of innate immunity genes and release of danger-associated molecular pattern molecules. We conclude that NTT-MMP-2 "primes" the kidney to enhanced susceptibility to I-R injury via induction of mitochondrial dysfunction. NTT-MMP-2 may be a novel AKI treatment target.

Chondrites: The Compaction of Fine Matrix and Matrix-like Chondrule Rims

NASA Astrophysics Data System (ADS)

Wasson, J. T.

1995-09-01

these two classes that I will assume that they can be treated as parts of a single statistical population. Published SEM images of matrix lumps and matrix-like rims show them to be relatively compact. Although some porosity is surely present as indicated by broad-beam electron-probe analysis totals <100%, it never reaches values comparable to those expected from low-velocity collisions in the solar nebula. Most chondrite researchers seem to hold that the low porosities reflect efficient packing of each grain as it accreted to the assemblage (i.e., as micrometer-size grains gradually covered the surface of a chondrule to form the matrix-like rim). I find this process very difficult to envision. If the velocities are low, the fluffy structures of Dodd and Meakin (1) should result; if the velocities are high, then rim erosion would seem to be more probable than growth. A possible scenario that avoids this dilemma is to form cm to m-size fluffy structures in low-turbulence regions of the nebular midplane. During accretion of these larger objects these experienced enough compaction to form tough, low-porosity (but unequilibrated) chondrites. If no chondrules were in a region, matrix lumps formed; if chondrules were widely separated, a matrix-like rim resulted. And, if chondrules were close to other chondrules or chondrule fragments, only small amounts of intervening fine-grained materials now separate them from their neighbors. During the compaction event, gas and dust migration occurred, and matrix filled all interstices, as now observed in the most primitive chondrites. According to this picture there could have been more diversity in the fine-grained nebular component before compaction occurred. These differences would be best preserved in matrix-like rims and matrix lumps. Much of the interchondrule matrix should consist of homogenized dust that was mixed during compaction-induced transport. References: [1] Donn B. and Meakin P. (1989) Proc. LPSC 19th, 577-580. [2

Salient Object Detection via Structured Matrix Decomposition.

PubMed

Peng, Houwen; Li, Bing; Ling, Haibin; Hu, Weiming; Xiong, Weihua; Maybank, Stephen J

2016-05-04

Low-rank recovery models have shown potential for salient object detection, where a matrix is decomposed into a low-rank matrix representing image background and a sparse matrix identifying salient objects. Two deficiencies, however, still exist. First, previous work typically assumes the elements in the sparse matrix are mutually independent, ignoring the spatial and pattern relations of image regions. Second, when the low-rank and sparse matrices are relatively coherent, e.g., when there are similarities between the salient objects and background or when the background is complicated, it is difficult for previous models to disentangle them. To address these problems, we propose a novel structured matrix decomposition model with two structural regularizations: (1) a tree-structured sparsity-inducing regularization that captures the image structure and enforces patches from the same object to have similar saliency values, and (2) a Laplacian regularization that enlarges the gaps between salient objects and the background in feature space. Furthermore, high-level priors are integrated to guide the matrix decomposition and boost the detection. We evaluate our model for salient object detection on five challenging datasets including single object, multiple objects and complex scene images, and show competitive results as compared with 24 state-of-the-art methods in terms of seven performance metrics.

The initiation and growth of delaminations induced by matrix microcracks in laminated composites

NASA Technical Reports Server (NTRS)

Nairn, J. A.; Hu, S.

1992-01-01

A recent variational mechanics analysis of microcracking damage in cross-ply laminates of the form /(S)/90n/s, where (S) is any orthotropic sublaminate much stiffer than /90n/, has been extended to account for the presence of delaminations emanating from the tips of microcracks in the /90 2n/T sublaminate. The new two-dimensional stress analysis is used to calculate the total strain energy, effective modulus, and longitudinal thermal expansion coefficient for a laminate having microcracks and delaminations. These results are used to calculate the energy release rate for the initiation and growth of a delamination induced by a matrix microcrack. At low crack densities, /(S)/90n/s laminates are expected to fail by microcracking and to show little or no delamination. At some critical crack density, which is a function of laminate structure and material properties, the energy release rate for delamination exceeds that for microcracking and delamination is predicted to dominate over microcracking. A quasi-three-dimensional model is used to predict the propagation of arbitrarily shaped delamination fronts. All predictions agree with experimental observations.

Exogenous steroid substrate modifies the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on estradiol production of human luteinized granulosa cells in vitro.

PubMed

Morán, F M; Lohstroh, P; VandeVoort, C A; Chen, J; Overstreet, J W; Conley, A J; Lasley, B L

2003-01-01

The in vitro effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on steroid metabolism in human luteinized granulosa cells (hLGC) have been summarized as a decreased estradiol (E(2)) production without altering either E(2) metabolism or cytochrome P450 aromatase activity. In the present study, hLGC were used to analyze the fate of different substrates for cytochrome P450 17alpha-hydroxylase/17,20-lyase (P450(c17)) in the presence or absence of TCDD. Human LGCs were plated directly on plastic culture dishes in medium supplemented with 2 IU/ml of hCG. TCDD (10 nM) or its solvent was added directly to the cells at the time of medium change, every 48 h for 8 days. The objective of the experiment was to test the hypothesis that exogenous steroid, substrate for P450(c17), would reduce the TCDD effects on E(2) synthesis. With dehydroepiandrosterone (DHEA) (a P450(c17) product), a dose-related increase in E(2) production was observed and the effect of TCDD on lowering E(2) production disappeared. In contrast, with increasing doses, up to 10 micro M, of pregnenolone (P(5)), no change in E(2) production was observed. However, 17alpha-hydroxypregnenolone (17P(5)) at 10 micro M produced a modest but significant increase in the E(2) production. Treatments with P(5) and 17P(5) did not alter the effect of TCDD on E(2) production. Radiolabeled substrate utilization by hLGC suggests that the principal metabolic pathway for Delta5 substrates is the conversion to a Delta4 product probably by a very active 3beta-hydroxysteroid dehydrogenase. We conclude that estrogen production by hLGC is limited at the level of lyase activity. Thus, these data suggest that the most likely target for the TCDD-induced inhibition of estrogen synthesis by hLGC is the 17,20-lyase activity of the P450(c17) enzyme complex.

Leptin produced by joint white adipose tissue induces cartilage degradation via upregulation and activation of matrix metalloproteinases.

PubMed

Hui, Wang; Litherland, Gary J; Elias, Martina S; Kitson, Gareth I; Cawston, Tim E; Rowan, Andrew D; Young, David A

2012-03-01

To investigate the effect of leptin on cartilage destruction. Collagen release was assessed in bovine cartilage explant cultures, while collagenolytic and gelatinolytic activities in culture supernatants were determined by bioassay and gelatin zymography. The expression of matrix metalloproteinases (MMP) was analysed by real-time RT-PCR. Signalling pathway activation was studied by immunoblotting. Leptin levels in cultured osteoarthritic joint infrapatellar fat pad or peri-enthesal deposit supernatants were measured by immunoassay. Leptin, either alone or in synergy with IL-1, significantly induced collagen release from bovine cartilage by upregulating collagenolytic and gelatinolytic activity. In chondrocytes, leptin induced MMP1 and MMP13 expression with a concomitant activation of STAT1, STAT3, STAT5, MAPK (JNK, Erk, p38), Akt and NF-κB signalling pathways. Selective inhibitor blockade of PI3K, p38, Erk and Akt pathways significantly reduced MMP1 and MMP13 expression in chondrocytes, and reduced cartilage collagen release induced by leptin or leptin plus IL-1. JNK inhibition had no effect on leptin-induced MMP13 expression or leptin plus IL-1-induced cartilage collagen release. Conditioned media from cultured white adipose tissue (WAT) from osteoarthritis knee joint fat pads contained leptin, induced cartilage collagen release and increased MMP1 and MMP13 expression in chondrocytes; the latter being partly blocked with an anti-leptin antibody. Leptin acts as a pro-inflammatory adipokine with a catabolic role on cartilage metabolism via the upregulation of proteolytic enzymes and acts synergistically with other pro-inflammatory stimuli. This suggests that the infrapatellar fat pad and other WAT in arthritic joints are local producers of leptin, which may contribute to the inflammatory and degenerative processes in cartilage catabolism, providing a mechanistic link between obesity and osteoarthritis.

Laser-induced emission spectroscopy of matrix-isolated carbon molecules: Experimental setup and new results on C3

NASA Astrophysics Data System (ADS)

Čermák, Ivo; Förderer, Markus; Čermáková, Iva; Kalhofer, Stefan; Stopka-Ebeler, Helmut; Monninger, Gerold; Krätschmer, Wolfgang

1998-06-01

We have studied small carbon molecules using a matrix-isolation technique. Our experimental setup is described in detail. The carbon clusters were produced by evaporating graphite and trapping the carbon-vapor molecules in solid argon, where molecular growth could be induced by controlled matrix annealing. To identify the produced molecules, absorption spectroscopy in the ultraviolet (UV)-visible and infrared (IR) spectral ranges was applied. Additional characterization of the excited and ground states of the molecules was obtained from emission and excitation spectra. The molecules were excited by a pulsed dye laser system and the emission spectra were recorded with a high-sensitivity photodiode-array spectrometer. We present our measurements on linear C3. The à 1Πu excited state of linear C3 was populated by the electronic transition à 1Πu←X˜ 1Σg+, and the corresponding excitation spectra of the C3 fluorescence (à 1Πu→X˜ 1Σg+) and phosphorescence (ã 3Πu→X˜ 1Σg+) were studied. Comparison of excitation and absorption spectra yielded information on site effects due to the matrix environment. Emission bands in the fluorescence and phosphorescence spectra up to vibrational energies of 8500 cm-1 could be observed. The radiation lifetime of the à 1Πu excited state of C3 in solid argon was found to be shorter than 10 ns. The phosphorescence transition ã 3Πu→X˜ 1Σg+ decays in about 10 ms and its rise indicates fast vibrational relaxation within the triplet system. Our data support a linear ground state geometry for C3 also in solid argon.

Vascular lysyl oxidase over-expression alters extracellular matrix structure and induces oxidative stress.

PubMed

Varona, Saray; García-Redondo, Ana B; Martínez-González, Jose; Salaices, Mercedes; Briones, Ana M; Rodríguez, Cristina

Lysyl oxidase (LOX) participates in the assembly of collagen and elastin fibres. The impact of vascular LOX over-expression on extracellular matrix (ECM) structure and its contribution to oxidative stress has been analysed. Studies were conducted on mice over-expressing LOX (Tg), specifically in smooth muscle cells (VSMC). Gene expression was assessed by real-time PCR analysis. Sirius Red staining, H 2 O 2 production and NADPH oxidase activity were analysed in different vascular beds. The size and number of fenestra of the internal elastic lamina were determined by confocal microscopy. LOX activity was up-regulated in VSMC of transgenic mice compared with cells from control animals. At the same time, transgenic cells deposited more organised elastin fibres and their supernatants induced a stronger collagen assembly in in vitro assays. Vascular collagen cross-linking was also higher in Tg mice, which showed a decrease in the size of fenestrae and an enhanced expression of Fibulin-5. Interestingly, higher H 2 O 2 production and NADPH oxidase activity was detected in the vascular wall from transgenic mice. The H 2 O 2 scavenger catalase attenuated the stronger deposition of mature elastin fibres induced by LOX transgenesis. LOX over-expression in VSMC was associated with a change in the structure of collagen and elastin fibres. LOX could constitute a novel source of oxidative stress that might participate in elastin changes and contribute to vascular remodelling. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

Serum, liver, and lung levels of the major extracellular matrix components at the early stage of BCG-induced granulomatosis depending on the infection route.

PubMed

Kim, L B; Shkurupy, V A; Putyatina, A N

2015-01-01

Experiments on the model of mouse BCG-induced granulomatous showed that the content of glycosaminoglycans and proteoglycans in the extracellular matrix of the liver and lungs are changed at the early stages of inflammation (days 3 and 30 postinfection) before cell destruction in the organs begins. This is related to degradation of extracellular matrix structures. Their high content in the blood and interstitium probably contributes to the formation of granulomas, fibroblast proliferation and organ fibrosis. These processes depend on the infection route that determines different conditions for generalization of the inflammation process. Intravenous method of vaccine injection is preferable to use when designing the experiments simulating tuberculosis granulomatosis, especially for the analysis of its early stages.

Dioxin exposure reduces the steroidogenic capacity of mouse antral follicles mainly at the level of HSD17B1 without altering atresia

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

Karman, Bethany N., E-mail: bklement@illinois.edu; Basavarajappa, Mallikarjuna S., E-mail: mbshivapur@gmail.com; Hannon, Patrick, E-mail: phannon2@illinois.edu

2012-10-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent ovarian toxicant. Previously, we demonstrated that in vitro TCDD (1 nM) exposure decreases production/secretion of the sex steroid hormones progesterone (P4), androstenedione (A4), testosterone (T), and 17β-estradiol (E2) in mouse antral follicles. The purpose of this study was to determine the mechanism by which TCDD inhibits steroidogenesis. Specifically, we examined the effects of TCDD on the steroidogenic enzymes, atresia, and the aryl hydrocarbon receptor (AHR) protein. TCDD exposure for 48 h increased levels of A4, without changing HSD3B1 protein, HSD17B1 protein, estrone (E1), T or E2 levels. Further, TCDD did not alter atresia ratings comparedmore » to vehicle at 48 h. TCDD, however, did down regulate the AHR protein at 48 h. TCDD exposure for 96 h decreased transcript levels for Cyp11a1, Cyp17a1, Hsd17b1, and Cyp19a1, but increased Hsd3b1 transcript. TCDD exposure particularly lowered both Hsd17b1 transcript and HSD17B1 protein. However, TCDD exposure did not affect levels of E1 in the media nor atresia ratings at 96 h. TCDD, however, decreased levels of the proapoptotic factor Bax. Collectively, these data suggest that TCDD exposure causes a major block in the steroidogenic enzyme conversion of A4 to T and E1 to E2 and that it regulates apoptotic pathways, favoring survival over death in antral follicles. Finally, the down‐regulation of the AHR protein in TCDD exposed follicles persisted at 96 h, indicating that the activation and proteasomal degradation of this receptor likely plays a central role in the impaired steroidogenic capacity and altered apoptotic pathway of exposed antral follicles. -- Highlights: ► TCDD disrupts steroidogenic enzymes in mouse antral follicles. ► TCDD particularly affects the HSD17B1 enzyme in mouse antral follicles. ► TCDD does not affect atresia ratings in mouse antral follicles. ► TCDD decreases levels of the proapoptitic factor Bax in mouse antral

Doxycycline down-regulates matrix metalloproteinase expression and inhibits NF-κB signaling in LPS-induced PC3 cells.

PubMed

Ogut, Deniz; Reel, Buket; Gonen Korkmaz, Ceren; Arun, Mehmet Zuhuri; Cilaker Micili, Serap; Ergur, Bekir Ugur

2016-01-01

Matrix metalloproteinase enzymes (MMPs) play important role in inflammation, malignant cell proliferation, invasion and angiogenesis by mediating extracellular matrix degradation. Doxycycline, a synthetic tetracycline, behaves as a MMP inhibitor at a subantimicrobial dose and inhibits tumor cell proliferation, invasion and angiogenesis. The aberrant activity of nuclear factor kappa B (NF-κB) causes activation of MMPs and thereby proliferation and invasion of cancer cells. The aim of this study was to investigate the effects of doxycycline on the expression of MMPs in lipopolysaccharide (LPS)-induced PC3 human prostate cancer cells and the possible role of NF-κB signaling. PC3 cells were incubated with LPS (0.5 μg/mL) for 24 h in the presence or absence of doxycycline (5 μg/mL). The effects of LPS and doxycycline on the expressions of MMP-2, MMP-8, MMP-9, MMP-10, NF-κB/p65, IκB-α, p-IκB-α, IKK-β were examined by Western blotting and immunohistochemistry in PC3 cells. Furthermore, relative proteinase activities of MMP-2 and MMP-9 were determined by gelatin zymography. LPS increased expression and activity of MMP-9 and expression of MMP-8, MMP-10, NF-κB /p65, p-IκB-α, IKK-β and doxycycline down-regulated its effects with the exception of MMP-10 expression. The expression of MMP-2 and IκB-α was affected by neither LPS nor doxycycline. Our findings indicate that doxycycline inhibits the expression of various MMPs and NF-κB signaling may play a role in the regulation of MMPs expression in LPS-induced PC3 human prostate cancer cells.

Hyaluronan Induces the Selective Accumulation of Matrix- and Cell-Associated Proteoglycans by Mesangial Cells

PubMed Central

Kastner, Sabine; Thomas, Gareth J.; Jenkins, Robert H.; Davies, Malcolm; Steadman, Robert

2007-01-01

Mesangial cells (MCs) are essential for normal renal function through the synthesis of their own extracellular matrix, which forms the structural support of the renal glomerulus. In many renal diseases this matrix is reorganized in response to a variety of cytokines and growth factors. This study examines proteoglycan and hyaluronan (HA) synthesis by MCs triggered by proinflammatory agents and investigates the effect of an exogenous HA matrix on matrix synthesis by MCs. Metabolic labeling, ion exchange and size exclusion chromatography, Western blotting, and immunocytochemistry were used to identify changes in matrix accumulation. When incubated with interleukin-1, platelet-derived growth factor, or fetal calf serum, MCs initiated rapid HA synthesis associated with the up-regulation of HA synthase-2 and increased the synthesis of versican, perlecan, and decorin/biglycan. HA was both released into the medium and incorporated into extensive pericellular coats. Adding exogenous HA to unstimulated cells that had undetectable pericellular coats of HA selectively reduced perlecan and versican turnover, whereas other proteoglycans were unaffected. These results suggest that high levels of HA in the mesangium in disease is a mechanism controlling the accumulation of specific mesangial matrix components. HA may thus be an attractive target for therapeutic intervention. PMID:17974600

Sub-inhibitory tigecycline concentrations induce extracellular matrix binding protein Embp dependent Staphylococcus epidermidis biofilm formation and immune evasion.

PubMed

Weiser, Julian; Henke, Hanae A; Hector, Nina; Both, Anna; Christner, Martin; Büttner, Henning; Kaplan, Jeffery B; Rohde, Holger

2016-09-01

Biofilm-associated Staphylococcus epidermidis implant infections are notoriously reluctant to antibiotic treatment. Here we studied the effect of sub-inhibitory concentrations of penicillin, oxacillin, vancomycin, daptomycin, linezolid and tigecycline on S. epidermidis 1585 biofilm formation, expression of extracellular matrix binding protein (Embp) and potential implications for S. epidermidis - macrophage interactions. Penicillin, vancomycin, daptomycin, and linezolid had no biofilm augmenting effect at any of the concentrations tested. In contrast, at sub-inhibitory concentrations tigecycline and oxacillin exhibited significant biofilm inducing activity. In S. epidermidis 1585, SarA is a negative regulator of giant 1 MDa Embp, and down regulation of sarA induces Embp-dependent assembly of a multi-layered biofilm architecture. Dot blot immune assays, confocal laser scanning microscopy, and qPCR showed that under biofilm inducing conditions, tigecycline augmented embp expression compared to the control grown without antibiotics. Conversely, expression of regulator sarA was suppressed, suggesting that tigecycline exerts its effects on embp expression through SarA. Tigecycline failed to induce biofilm formation in embp transposon mutant 1585-M135, proving that under these conditions Embp up-regulation is necessary for biofilm accumulation. As a functional consequence, tigecycline induced biofilm formation significantly impaired the up-take of S. epidermidis by mouse macrophage-like cell line J774A.1. Our data provide novel evidence for the molecular basis of antibiotic induced biofilm formation, a phenotype associated with inherently increased antimicrobial tolerance. While this could explain failure of antimicrobial therapies, persistence of S. epidermidis infections in the presence of sub-inhibitory antimicrobials is additionally propelled by biofilm-related impairment of macrophage-mediated pathogen eradication. Copyright © 2016 Elsevier GmbH. All rights

The extracellular matrix in myocardial injury, repair, and remodeling

PubMed Central

2017-01-01

The cardiac extracellular matrix (ECM) not only provides mechanical support, but also transduces essential molecular signals in health and disease. Following myocardial infarction, dynamic ECM changes drive inflammation and repair. Early generation of bioactive matrix fragments activates proinflammatory signaling. The formation of a highly plastic provisional matrix facilitates leukocyte infiltration and activates infarct myofibroblasts. Deposition of matricellular proteins modulates growth factor signaling and contributes to the spatial and temporal regulation of the reparative response. Mechanical stress due to pressure and volume overload and metabolic dysfunction also induce profound changes in ECM composition that contribute to the pathogenesis of heart failure. This manuscript reviews the role of the ECM in cardiac repair and remodeling and discusses matrix-based therapies that may attenuate remodeling while promoting repair and regeneration. PMID:28459429

Porphyromonas gingivalis-mediated shedding of extracellular matrix metalloproteinase inducer (EMMPRIN) by oral epithelial cells: a potential role in inflammatory periodontal disease.

PubMed

Feldman, Mark; La, Vu Dang; Lombardo Bedran, Telma Blanca; Palomari Spolidorio, Denise Madalena; Grenier, Daniel

2011-12-01

Extracellular matrix metalloproteinase inducer (EMMPRIN) or CD147 is a transmembrane glycoprotein expressed by various cell types, including oral epithelial cells. Recent studies have brought evidence that EMMPRIN plays a role in periodontitis. In the present study, we investigated the effect of Porphyromonas gingivalis, a major pathogen in chronic periodontitis, on the shedding of membrane-anchored EMMPRIN and on the expression of the EMMPRIN gene by oral epithelial cells. A potential contribution of shed EMMPRIN to the inflammatory process of periodontitis was analyzed by evaluating the effect of recombinant EMMPRIN on cytokine and matrix metalloproteinase (MMP) secretion by human gingival fibroblasts. ELISA and immunofluorescence analyses revealed that P. gingivalis mediated the shedding of epithelial cell-surface EMMPRIN in a dose- and time-dependent manner. Cysteine proteinase (gingipain)-deficient P. gingivalis mutants were used to demonstrate that both Arg- and Lys-gingipain activities are involved in EMMPRIN shedding. Real-time PCR showed that P. gingivalis had no significant effect on the expression of the EMMPRIN gene in epithelial cells. Recombinant EMMPRIN induced the secretion of IL-6 and MMP-3 by gingival fibroblasts, a phenomenon that appears to involve mitogen activated protein kinases. The present study brought to light a new mechanism by which P. gingivalis can promote the inflammatory response during periodontitis. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

ERK-regulated αB-crystallin induction by matrix detachment inhibits anoikis and promotes lung metastasis in vivo.

PubMed

Malin, D; Strekalova, E; Petrovic, V; Rajanala, H; Sharma, B; Ugolkov, A; Gradishar, W J; Cryns, V L

2015-11-05

Evasion of extracellular matrix detachment-induced apoptosis ('anoikis') is a defining characteristic of metastatic tumor cells. The ability of metastatic carcinoma cells to survive matrix detachment and escape anoikis enables them to disseminate as viable circulating tumor cells and seed distant organs. Here we report that αB-crystallin, an antiapoptotic molecular chaperone implicated in the pathogenesis of diverse poor-prognosis solid tumors, is induced by matrix detachment and confers anoikis resistance. Specifically, we demonstrate that matrix detachment downregulates extracellular signal-regulated kinase (ERK) activity and increases αB-crystallin protein and messenger RNA (mRNA) levels. Moreover, we show that ERK inhibition in adherent cancer cells mimics matrix detachment by increasing αB-crystallin protein and mRNA levels, whereas constitutive ERK activation suppresses αB-crystallin induction during matrix detachment. These findings indicate that ERK inhibition is both necessary and sufficient for αB-crystallin induction by matrix detachment. To examine the functional consequences of αB-crystallin induction in anoikis, we stably silenced αB-crystallin in two different metastatic carcinoma cell lines. Strikingly, silencing αB-crystallin increased matrix detachment-induced caspase activation and apoptosis but did not affect cell viability of adherent cancer cells. In addition, silencing αB-crystallin in metastatic carcinoma cells reduced the number of viable circulating tumor cells and inhibited lung metastasis in two orthotopic models, but had little or no effect on primary tumor growth. Taken together, our findings point to αB-crystallin as a novel regulator of anoikis resistance that is induced by matrix detachment-mediated suppression of ERK signaling and promotes lung metastasis. Our results also suggest that αB-crystallin represents a promising molecular target for antimetastatic therapies.

Epithelial expression of extracellular matrix metalloproteinase inducer/CD147 and matrix metalloproteinase-2 in neoplasms and precursor lesions derived from cutaneous squamous cells: An immunohistochemical study.

PubMed

Ayva, Sebnem Kupana; Karabulut, Ayse Anil; Akatli, Ayşe Nur; Atasoy, Pinar; Bozdogan, Onder

2013-10-01

Extracellular matrix metalloproteinase inducer (CD147) is a transmembrane glycoprotein involved in the regulation of matrix metalloproteinases (MMPs). The study investigated CD147 and MMP-2 expression in epidermis of cutaneous squamous lesions. CD147 and MMP-2 expressions were evaluated immunohistochemically in 44 specimens: 18 actinic keratoses (AK), 6 squamous cell carcinomas in situ (SCCIS), 13 squamous cell carcinomas (SCC; peritumoral and invasive portions assessed), and 7 normal skins. Patterns of expression were assessed, with MMP-2 in nuclei (MMP-2n) and cytoplasm (MMP-2c) evaluated separately. The expression of each marker was quantified using a calculated immunohistochemical/histologic score (H-score). Correlations were analyzed for the marker H-scores in each study group. Associations between H-scores and histopathologic parameters were also evaluated. CD147 H-score was the highest in SCC (invasive islands), followed by AK, SCCIS, and control specimens, respectively. MMP-2n and MMP-2c H-scores were the highest in AK, followed by SCCIS, SCC, and control specimens, respectively. MMP-2c and MMP-2n H-scores were significantly higher in peritumoral epidermis than in invasive islands of SCC. MMP-2c and CD147 H-scores were positively correlated in the peritumoral SCCs. CD147 H-score was positively correlated with tumor differentiation in SCC. The findings suggest that overexpression of CD147 plays a role in the development of SCC. Copyright © 2013 Elsevier GmbH. All rights reserved.

Matrix completion by deep matrix factorization.

PubMed

Fan, Jicong; Cheng, Jieyu

2018-02-01

Conventional methods of matrix completion are linear methods that are not effective in handling data of nonlinear structures. Recently a few researchers attempted to incorporate nonlinear techniques into matrix completion but there still exists considerable limitations. In this paper, a novel method called deep matrix factorization (DMF) is proposed for nonlinear matrix completion. Different from conventional matrix completion methods that are based on linear latent variable models, DMF is on the basis of a nonlinear latent variable model. DMF is formulated as a deep-structure neural network, in which the inputs are the low-dimensional unknown latent variables and the outputs are the partially observed variables. In DMF, the inputs and the parameters of the multilayer neural network are simultaneously optimized to minimize the reconstruction errors for the observed entries. Then the missing entries can be readily recovered by propagating the latent variables to the output layer. DMF is compared with state-of-the-art methods of linear and nonlinear matrix completion in the tasks of toy matrix completion, image inpainting and collaborative filtering. The experimental results verify that DMF is able to provide higher matrix completion accuracy than existing methods do and DMF is applicable to large matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro model to study the effects of matrix stiffening on Ca2+ handling and myofilament function in isolated adult rat cardiomyocytes

PubMed Central

Najafi, Aref; Fontoura, Dulce; Valent, Erik; Goebel, Max; Kardux, Kim; Falcão‐Pires, Inês; van der Velden, Jolanda

2017-01-01

Key points This paper describes a novel model that allows exploration of matrix‐induced cardiomyocyte adaptations independent of the passive effect of matrix rigidity on cardiomyocyte function.Detachment of adult cardiomyocytes from the matrix enables the study of matrix effects on cell shortening, Ca2+ handling and myofilament function.Cell shortening and Ca2+ handling are altered in cardiomyocytes cultured for 24 h on a stiff matrix.Matrix stiffness‐impaired cardiomyocyte contractility is reversed upon normalization of extracellular stiffness.Matrix stiffness‐induced reduction in unloaded shortening is more pronounced in cardiomyocytes isolated from obese ZSF1 rats with heart failure with preserved ejection fraction compared to lean ZSF1 rats. Abstract Extracellular matrix (ECM) stiffening is a key element of cardiac disease. Increased rigidity of the ECM passively inhibits cardiac contraction, but if and how matrix stiffening also actively alters cardiomyocyte contractility is incompletely understood. In vitro models designed to study cardiomyocyte–matrix interaction lack the possibility to separate passive inhibition by a stiff matrix from active matrix‐induced alterations of cardiomyocyte properties. Here we introduce a novel experimental model that allows exploration of cardiomyocyte functional alterations in response to matrix stiffening. Adult rat cardiomyocytes were cultured for 24 h on matrices of tuneable stiffness representing the healthy and the diseased heart and detached from their matrix before functional measurements. We demonstrate that matrix stiffening, independent of passive inhibition, reduces cell shortening and Ca2+ handling but does not alter myofilament‐generated force. Additionally, detachment of adult cultured cardiomyocytes allowed the transfer of cells from one matrix to another. This revealed that stiffness‐induced cardiomyocyte changes are reversed when matrix stiffness is normalized. These matrix stiffness‐induced

Disposition of toxic PCB congeners in snapping turtle eggs: expressed as toxic equivalents of TCDD

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

Bryan, A.M.; Stone, W.B.; Olafsson, P.G.

1987-11-01

Studies of snapping turtles, taken from the region of the Upper Hudson River, in New York State, revealed exceedingly high levels of PCBs in the adipose tissue. There is evidence to suggest that large reserves of fat provide protection against chlorinated hydrocarbon toxicity. Such storage may protect snapping turtle eggs from disposition of toxic PCB congeners and account for the apparent absence of reports regarding detrimental effects on the hatchability of eggs from turtles living in the vicinity of the upper Hudson River. The present study was undertaken to determine if indeed these eggs are protected against disposition of toxicmore » PCB congeners by the presence of large reserves of fat. Although tissue volumes play an important role in determining the initial site of disposition, the major factor controlling the elimination of these compounds involves metabolism. For simple halogenated benzenes as well as for more complex halogenated biphenyls, oxidative metabolism catalyzed by P-448, occurs primarily at the site of two adjacent unsubstituted carbon atoms via arene oxide formation leading to the formation of water soluble metabolites. Toxicological studies have demonstrated that the most toxic PCB congeners, isosteriomers of tetrachlorodibenzo-p-dioxin (TCDD), require no metabolic activation. These compounds have chlorine atoms in the meta and para positions of both rings. It may be concluded that the structures of PCB congeners and isomers which favor induction of cytochrome P-448 are also those which are toxic and resist metabolism. It is the objective of the present study to determine if the heavy fat bodies of the female turtle provide a sufficiently large sink to retain the toxic congeners and prevent their incorporation into the eggs.« less

Acetylcholine-induced activation of M3 muscarinic receptors stimulates robust matrix metalloproteinase gene expression in human colon cancer cells.

PubMed

Xie, Guofeng; Cheng, Kunrong; Shant, Jasleen; Raufman, Jean-Pierre

2009-04-01

Previously, we showed that ACh-induced proliferation of human colon cancer cells is mediated by transactivation of epidermal growth factor (EGF) receptors (EGFRs). In the present study, we elucidate the molecular mechanism underlying this action. ACh-induced proliferation of H508 colon cancer cells, which express exclusively M3 muscarinic receptors (M3Rs), was attenuated by anti-EGFR ligand binding domain antibody, a broad-spectrum matrix metalloproteinase (MMP) inhibitor, anti-MMP7 antibody, a diphtheria toxin analog that blocks release of an EGFR ligand [heparin-binding EGF-like growth factor (HBEGF)], and anti-HBEGF antibody. Conditioned media from ACh-treated H508 cells induced proliferation of SNU-C4 colon cancer cells that express EGFR but not M3R. These actions were attenuated by an EGFR inhibitor and by anti-EGFR and anti-HBEGF antibodies. In H508, but not SNU-C4, colon cancer cells, ACh caused a striking dose- and time-dependent increase in levels of MMP7 mRNA and MMP7 protein. Similarly, ACh induced robust MMP1 and MMP10 gene transcription. ACh-induced MMP1, MMP7, and MMP10 gene transcription was attenuated by atropine, anti-EGFR antibody, and chemical inhibitors of EGFR and ERK activation. In contrast, inhibitors of phosphatidylinositol 3-kinase and NF-kappaB activation did not alter MMP gene transcription. Collectively, these findings indicate that MMP7-catalyzed release of HBEGF mediates ACh-induced transactivation of EGFR and consequent proliferation of colon cancer cells. ACh-induced activation of EGFR and downstream ERK signaling also regulates transcriptional activation of MMP7, thereby identifying a novel feed-forward mechanism for neoplastic cell proliferation.

Acetylcholine-induced activation of M3 muscarinic receptors stimulates robust matrix metalloproteinase gene expression in human colon cancer cells

PubMed Central

Xie, Guofeng; Cheng, Kunrong; Shant, Jasleen; Raufman, Jean-Pierre

2009-01-01

Previously, we showed that ACh-induced proliferation of human colon cancer cells is mediated by transactivation of epidermal growth factor (EGF) receptors (EGFRs). In the present study, we elucidate the molecular mechanism underlying this action. ACh-induced proliferation of H508 colon cancer cells, which express exclusively M3 muscarinic receptors (M3Rs), was attenuated by anti-EGFR ligand binding domain antibody, a broad-spectrum matrix metalloproteinase (MMP) inhibitor, anti-MMP7 antibody, a diphtheria toxin analog that blocks release of an EGFR ligand [heparin-binding EGF-like growth factor (HBEGF)], and anti-HBEGF antibody. Conditioned media from ACh-treated H508 cells induced proliferation of SNU-C4 colon cancer cells that express EGFR but not M3R. These actions were attenuated by an EGFR inhibitor and by anti-EGFR and anti-HBEGF antibodies. In H508, but not SNU-C4, colon cancer cells, ACh caused a striking dose- and time-dependent increase in levels of MMP7 mRNA and MMP7 protein. Similarly, ACh induced robust MMP1 and MMP10 gene transcription. ACh-induced MMP1, MMP7, and MMP10 gene transcription was attenuated by atropine, anti-EGFR antibody, and chemical inhibitors of EGFR and ERK activation. In contrast, inhibitors of phosphatidylinositol 3-kinase and NF-κB activation did not alter MMP gene transcription. Collectively, these findings indicate that MMP7-catalyzed release of HBEGF mediates ACh-induced transactivation of EGFR and consequent proliferation of colon cancer cells. ACh-induced activation of EGFR and downstream ERK signaling also regulates transcriptional activation of MMP7, thereby identifying a novel feed-forward mechanism for neoplastic cell proliferation. PMID:19221016

Leptospira interrogans induces uterine inflammatory responses and abnormal expression of extracellular matrix proteins in dogs.

PubMed

Wang, Wei; Gao, Xuejiao; Guo, Mengyao; Zhang, Wenlong; Song, Xiaojing; Wang, Tiancheng; Zhang, Zecai; Jiang, Haichao; Cao, Yongguo; Zhang, Naisheng

2014-10-01

Leptospira interrogans (L. interrogans), a worldwide zoonosis, infect humans and animals. In dogs, four syndromes caused by leptospirosis have been identified: icteric, hemorrhagic, uremic (Stuttgart disease) and reproductive (abortion and premature or weak pups), and also it caused inflammation. Extracellular matrix (ECM) is a complex mixture of matrix molecules that is crucial to the reproduction. Both inflammatory response and ECM are closed relative to reproductive. The aim of this study was to clarify how L. interrogans affected the uterus of dogs, by focusing on the inflammatory responses, and ECM expression in dogs uterine tissue infected by L. interrogans. In the present study, 27 dogs were divided into 3 groups, intrauterine infusion with L. interrogans, to make uterine infection, sterile EMJH, and normal saline as a control, respectively. The uteruses were removed by surgical operation in 10, 20, and 30 days, respectively. The methods of histopathological analysis, ELISA, Western blot and qPCR were used. The results showed that L. interrogans induced significantly inflammatory responses, which were characterized by inflammatory cellular infiltration and high expression levels of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in uterine tissue of these dogs. Furthermore, L. interrogans strongly down-regulated the expression of ECM (collagens (CL) IV, fibronectins (FN) and laminins (LN)) in mRNA and protein levels. These data indicated that strongly inflammatory responses, and abnormal regulation of ECM might contribute to the proliferation of dogs infected by L. interrogans. Copyright © 2014 Elsevier Ltd. All rights reserved.

Embryo toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the wood duck (Aix sponsa)

USGS Publications Warehouse

Augspurger, T.P.; Tillitt, D.E.; Bursian, S.J.; Fitzgerald, S.D.; Hinton, D.E.; Di Giulio, R.T.

2008-01-01

We examined the sensitivity of the wood duck (Aix sponsa) embryo to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by injecting the toxicant into their eggs. Six groups of wood duck eggs (n = 35 to 211 per trial) were injected with 0 to 4600 pg TCDD/g egg between 2003 and 2005. Injections were made into yolk prior to incubation, and eggs were subsequently incubated and assessed weekly for mortality. Significant TCDD-induced mortality was not observed through day 25 (90% of incubation). Liver, heart, eye, and brain histology were generally unremarkable. Hepatic ethoxyresorufin-O-deethylase activity, a biomarker of dioxin-like compound exposure, was induced by 12-fold in the 4600 pg/g treatment relative to controls. The median lethal dose for chicken (Gallus domesticus) eggs we dosed identically to wood duck eggs was about 100 pg/g, similar to other assessments of chickens. Among dioxin-like compound embryo lethality data for 15 avian genera, the wood duck 4600 pg/g no-observed-effect level ranks near the middle. Because no higher doses were tested, wood ducks may be like other waterfowl (order Anseriformes), which are comparatively tolerant to embryo mortality from polychlorinated dibenzo-p-dioxins and dibenzofurans when exposed by egg injection. ?? 2008 US Government.

Matrix-specific protein kinase A signaling regulates p21 activated kinase activation by flow in endothelial cells

PubMed Central

Funk, Steven Daniel; Yurdagul, Arif; Green, Jonette M.; Jhaveri, Krishna A.; Schwartz, Martin Alexander; Orr, A. Wayne

2010-01-01

Rationale Atherosclerosis is initiated by blood flow patterns that activate inflammatory pathways in endothelial cells. Activation of inflammatory signaling by fluid shear stress is highly dependent on the composition of the subendothelial extracellular matrix. The basement membrane proteins laminin and collagen found in normal vessels suppress flow-induced p21 activated kinase (PAK) and NF-κB activation. By contrast, the provisional matrix proteins fibronectin and fibrinogen found in wounded or inflamed vessels support flow-induced PAK and NF-κB activation. PAK mediates both flow-induced permeability and matrix-specific activation of NF-κB. Objective To elucidate the mechanisms regulating matrix-specific PAK activation. Methods and Results We now show that matrix composition does not affect the upstream pathway by which flow activates PAK (integrin activation, Rac). Instead basement membrane proteins enhance flow-induced protein kinase A (PKA) activation, which suppresses PAK. Inhibiting PKA restored flow-induced PAK and NF-κB activation in cells on basement membrane proteins, whereas stimulating PKA inhibited flow-induced activation of inflammatory signaling in cells on fibronectin. PKA suppressed inflammatory signaling through PAK inhibition. Activating PKA by injection of the PGI2 analog iloprost reduced PAK activation and inflammatory gene expression at sites of disturbed flow in vivo, whereas inhibiting PKA by PKI injection enhanced PAK activation and inflammatory gene expression. Inhibiting PAK prevented the enhancement of inflammatory gene expression by PKI. Conclusions Basement membrane proteins inhibit inflammatory signaling in endothelial cells via PKA-dependent inhibition of PAK. PMID:20224042

In vitro model to study the effects of matrix stiffening on Ca2+ handling and myofilament function in isolated adult rat cardiomyocytes.

PubMed

van Deel, Elza D; Najafi, Aref; Fontoura, Dulce; Valent, Erik; Goebel, Max; Kardux, Kim; Falcão-Pires, Inês; van der Velden, Jolanda

2017-07-15

This paper describes a novel model that allows exploration of matrix-induced cardiomyocyte adaptations independent of the passive effect of matrix rigidity on cardiomyocyte function. Detachment of adult cardiomyocytes from the matrix enables the study of matrix effects on cell shortening, Ca 2+ handling and myofilament function. Cell shortening and Ca 2+ handling are altered in cardiomyocytes cultured for 24 h on a stiff matrix. Matrix stiffness-impaired cardiomyocyte contractility is reversed upon normalization of extracellular stiffness. Matrix stiffness-induced reduction in unloaded shortening is more pronounced in cardiomyocytes isolated from obese ZSF1 rats with heart failure with preserved ejection fraction compared to lean ZSF1 rats. Extracellular matrix (ECM) stiffening is a key element of cardiac disease. Increased rigidity of the ECM passively inhibits cardiac contraction, but if and how matrix stiffening also actively alters cardiomyocyte contractility is incompletely understood. In vitro models designed to study cardiomyocyte-matrix interaction lack the possibility to separate passive inhibition by a stiff matrix from active matrix-induced alterations of cardiomyocyte properties. Here we introduce a novel experimental model that allows exploration of cardiomyocyte functional alterations in response to matrix stiffening. Adult rat cardiomyocytes were cultured for 24 h on matrices of tuneable stiffness representing the healthy and the diseased heart and detached from their matrix before functional measurements. We demonstrate that matrix stiffening, independent of passive inhibition, reduces cell shortening and Ca 2+ handling but does not alter myofilament-generated force. Additionally, detachment of adult cultured cardiomyocytes allowed the transfer of cells from one matrix to another. This revealed that stiffness-induced cardiomyocyte changes are reversed when matrix stiffness is normalized. These matrix stiffness-induced changes in cardiomyocyte

Calibration approach for extremely variable laser induced plasmas and a strategy to reduce the matrix effect in general

NASA Astrophysics Data System (ADS)

Lazic, V.; De Ninno, A.

2017-11-01

The laser induced plasma spectroscopy was applied on particles attached on substrate represented by a silica wafer covered with a thin oil film. The substrate itself weakly interacts with a ns Nd:YAG laser (1064 nm) while presence of particles strongly enhances the plasma emission, here detected by a compact spectrometer array. Variations of the sample mass from one laser spot to another exceed one order of magnitude, as estimated by on-line photography and the initial image calibration for different sample loadings. Consequently, the spectral lines from particles show extreme intensity fluctuations from one sampling point to another, between the detection threshold and the detector's saturation in some cases. In such conditions the common calibration approach based on the averaged spectra, also when considering ratios of the element lines i.e. concentrations, produces errors too large for measuring the sample compositions. On the other hand, intensities of an analytical and the reference line from single shot spectra are linearly correlated. The corresponding slope depends on the concentration ratio and it is weakly sensitive to fluctuations of the plasma temperature inside the data set. A use of the slopes for constructing the calibration graphs significantly reduces the error bars but it does not eliminate the point scattering caused by the matrix effect, which is also responsible for large differences in the average plasma temperatures among the samples. Well aligned calibration points were obtained after identifying the couples of transitions less sensitive to variations of the plasma temperature, and this was achieved by simple theoretical simulations. Such selection of the analytical lines minimizes the matrix effect, and together with the chosen calibration approach, allows to measure the relative element concentrations even in highly unstable laser induced plasmas.

10-Hydroxy-2-decenoic acid prevents ultraviolet A-induced damage and matrix metalloproteinases expression in human dermal fibroblasts.

PubMed

Zheng, Jinfen; Lai, Wei; Zhu, Guoxing; Wan, Miaojian; Chen, Jian; Tai, Yan; Lu, Chun

2013-10-01

10-Hydroxy-2-decenoic acid (10-HDA) is a major fatty acid component of royal jelly, which has been reported to have a variety of beneficial pharmacological characteristics. However, the effects of 10-HDA on skin photoageing and its potential mechanism of action are unclear. We investigated the protective effects of 10-HDA on ultraviolet (UV) A-induced damage in human dermal fibroblasts (HDFs). We then explored the inhibitory effects of 10-HDA on UVA-induced matrix metalloproteinases (MMPs) expression and elucidated the signalling pathways controlling MMPs inhibition. Primary human dermal fibroblasts were exposed to UVA. Cell proliferation, cellular senescent state and collagen content were analysed using CCK-8, senescence-associated β-galactosidase staining and Sircol collagen assay, respectively. Fluorometric assays were performed to detect the formation of reactive oxygen species (ROS) in the cells. The mRNA levels of MMP-1, MMP-3 and type I (α1) collagen were determined by quantitative real-time PCR. Western blot was applied to detect the expression of MMP-1, MMP-3, JNK and p38 MAPK. HDFs treated with 10-HDA were significantly protected from UVA-induced cytotoxicity, ROS, cellular senescence and stimulated collagen production. Moreover, 10-HDA suppressed the UVA-induced expression of MMP-1 and MMP-3 at both the transcriptional and protein levels. Treatment with 10-HDA also reduced the UVA-induced activation of the JNK and p38 MAPK pathways. The data obtained in this study provide evidence that 10-HDA could prevent UVA-induced damage and inhibit MMP-1 and MMP-3 expressions. Therefore, 10-HDA may be a potential agent for the prevention and treatment of skin photoageing. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology © 2012 European Academy of Dermatology and Venereology.

Interplay of matrix metalloproteinases, tissue inhibitors of metalloproteinases and their regulators in cardiac matrix remodeling.

PubMed

Li, Y Y; McTiernan, C F; Feldman, A M

2000-05-01

Myocardial fibrosis due to maladaptive extracellular matrix remodeling contributes to dysfunction of the failing heart. Further elucidation of the mechanism by which myocardial fibrosis and dilatation can be prevented or even reversed remains of great interest as a potential means to limit myocardial remodeling and dysfunction. Matrix metalloproteinases (MMPs) are the driving force behind extracellular matrix degradation during remodeling and are increased in the failing human heart. MMPs are regulated by a variety of growth factors, cytokines, and matrix fragments such as matrikines. In the present report, we discuss the regulation of MMPs, the role of MMPs in the development of cardiac fibrosis, and the modulation of MMP activity using gene transfer and knockout technologies. We also present recent findings from our laboratory on the regulation of the extracellular MMP inducer (EMMPRIN), MMPs, and transforming growth factor-beta(1) in the failing human heart before and after left ventricular assist device support, as well as the possibility of preventing ventricular fibrosis using different anti-MMP strategies. Several studies suggest that such modulation of MMP activity can alter ventricular remodeling, myocardial dysfunction, and the progression of heart failure. It is therefore suggested that the interplay of MMPs and their regulators is important in the development of the heart failure phenotype, and myocardial fibrosis in heart failure may be modified by modulating MMP activity.

Increased arylhydrocarbon receptor expression offers a potential therapeutic target for pancreatic cancer.

PubMed

Koliopanos, Alexander; Kleeff, Jörg; Xiao, Yi; Safe, Stephen; Zimmermann, Arthur; Büchler, Markus W; Friess, Helmut

2002-09-05

The arylhydrocarbon receptor (AhR) was initially identified as a member of the adaptive metabolic and toxic response pathway to polycyclic aromatic hydrocarbons and to halogenated dibenzo-p-dioxins and dibenzofurans. In the present study, we sought to determine the functional significance of the AhR pathway in pancreatic carcinogenesis. AhR expression was analysed by Northern blotting. The exact site of AhR expression was analysed by in situ hybridization and immunohistochemistry. The effects of TCDD and four selective AhR agonists on pancreatic cancer cell lines were investigated by growth assays, apoptosis assays, and induction of the cyclin-dependent kinase inhibitor p21. There was strong AhR mRNA expression in 14 out of 15 pancreatic cancer samples, weak expression in chronic pancreatitis tissues, and faint expression in all normal pancreata. In pancreatic cancer tissues, AhR mRNA and protein expression were localized in the cytoplasm of pancreatic cancer cells. TCDD and the four AhR agonists inhibited pancreatic cancer cell growth in a dose-dependent manner, and decreased anchorage-independent cell growth. DAPI staining did not reveal nuclear fragmentation and CYP1A1 and was not induced by TCDD and AhR agonists. In contrast, TCDD and AhR agonists induced the expression of the cyclin-dependent kinase inhibitor p21. In conclusion, the relatively non-toxic AhR agonists caused growth inhibition in pancreatic cancer cells with high AhR expression levels via cell cycle arrest. In addition, almost all human pancreatic cancer tissues expressed this receptor at high levels, suggesting that these or related compounds may play a role in the therapy of pancreatic cancer in the future.

Procollagen III N-terminal Propeptide and Desmosine are Released by Matrix Destruction in Pulmonary Tuberculosis

PubMed Central

Seddon, Jo; Kasprowicz, Victoria; Walker, Naomi F.; Yuen, Ho Ming; Sunpath, Henry; Tezera, Liku; Meintjes, Graeme; Wilkinson, Robert J.; Bishai, William R.; Friedland, Jon S.; Elkington, Paul T.

2013-01-01

Background. Tuberculosis is transmitted by patients with pulmonary disease. Matrix metalloproteinases (MMPs) drive lung destruction in tuberculosis but the resulting matrix degradation products (MDPs) have not been studied. We investigate the hypothesis that MMP activity generates matrix turnover products as correlates of lung pathology. Methods. Induced sputum and plasma were collected prospectively from human immunodeficiency virus (HIV) positive and negative patients with pulmonary tuberculosis and controls. Concentrations of MDPs and MMPs were analyzed by ELISA and Luminex array in 2 patient cohorts. Results. Procollagen III N-terminal propeptide (PIIINP) was 3.8-fold higher in induced sputum of HIV-uninfected tuberculosis patients compared to controls and desmosine, released during elastin degradation, was 2.4-fold higher. PIIINP was elevated in plasma of tuberculosis patients. Plasma PIIINP correlated with induced sputum MMP-1 concentrations and radiological scores, demonstrating that circulating MDPs reflect lung destruction. In a second patient cohort of mixed HIV seroprevalence, plasma PIIINP concentration was increased 3.0-fold above controls (P < .001). Plasma matrix metalloproteinase-8 concentrations were also higher in tuberculosis patients (P = .001). Receiver operating characteristic analysis utilizing these 2 variables demonstrated an area under the curve of 0.832 (P < .001). Conclusions. In pulmonary tuberculosis, MMP-driven immunopathology generates matrix degradation products. PMID:23922364

UV-induced inhibition of adipokine production in subcutaneous fat aggravates dermal matrix degradation in human skin.

PubMed

Kim, Eun Ju; Kim, Yeon Kyung; Kim, Min-Kyoung; Kim, Sungsoo; Kim, Jin Yong; Lee, Dong Hun; Chung, Jin Ho

2016-05-10

Ultraviolet (UV) exposure to the human skin reduces triglycerides contents and lipid synthesis in the subcutaneous (SC) fat. Because adiponectin and leptin are the most abundant adipokines from the SC fat, we aim to investigate how they interact with UV exposure and skin aging. The expressions of adiponectin and leptin were significantly decreased in SC fat of sun-exposed forearm skin, in comparison with that of sun-protected buttock skin of the same elderly individuals, indicating that chronic UV exposure decreases both adipokines. Acute UV irradiation also decreased the expressions of adiponectin and leptin in SC fat. The expressions of adiponectin receptor 1/2 and leptin receptor were significantly decreased in the dermis as well as in SC fat. Moreover, while exogenous adiponectin and leptin administration prevented UV- and TNF-α induced matrix metalloproteinase (MMP)-1 expression, they also increased UV- and TNF-α induced reduction of type 1 procollagen production. Silencing of adiponectin, leptin or their receptors led to an increased MMP-1 and a decreased type 1 procollagen expression, which was reversed by treatment with recombinant human adiponectin or leptin. In conclusion, UV exposure decreases the expression of adiponectin and leptin, leading to the exacerbation of photoaging by stimulating MMP-1 expression and inhibiting procollagen synthesis.

Minocycline Attenuates Neonatal Germinal-Matrix-Hemorrhage-Induced Neuroinflammation and Brain Edema by Activating Cannabinoid Receptor 2.

PubMed

Tang, Jun; Chen, Qianwei; Guo, Jing; Yang, Liming; Tao, Yihao; Li, Lin; Miao, Hongping; Feng, Hua; Chen, Zhi; Zhu, Gang

2016-04-01

Germinal matrix hemorrhage (GMH) is the most common neurological disease of premature newborns leading to detrimental neurological sequelae. Minocycline has been reported to play a key role in neurological inflammatory diseases by controlling some mechanisms that involve cannabinoid receptor 2 (CB2R). The current study investigated whether minocycline reduces neuroinflammation and protects the brain from injury in a rat model of collagenase-induced GMH by regulating CB2R activity. To test this hypothesis, the effects of minocycline and a CB2R antagonist (AM630) were evaluated in male rat pups that were post-natal day 7 (P7) after GMH. We found that minocycline can lead to increased CB2R mRNA expression and protein expression in microglia. Minocycline significantly reduced GMH-induced brain edema, microglial activation, and lateral ventricular volume. Additionally, minocycline enhanced cortical thickness after injury. All of these neuroprotective effects of minocycline were prevented by AM630. A cannabinoid CB2 agonist (JWH133) was used to strengthen the hypothesis, which showed the identical neuroprotective effects of minocycline. Our study demonstrates, for the first time, that minocycline attenuates neuroinflammation and brain injury in a rat model of GMH, and activation of CBR2 was partially involved in these processes.

Dynamic laser-induced effects in nanocomposite systems based on the cadmium sulfide quantum dots in a silicate matrix.

PubMed

Voznesenskiy, S S; Sergeev, A A; Postnova, I V; Galkina, A N; Shchipunov, Yu A; Kulchin, Yu N

2015-02-23

In this paper we study the laser-induced modification of optical properties of nanocomposite based on cadmium sulphide quantum dots encapsulated into thiomalic acid shell which were embedded into a porous silica matrix. It was found that exposure to laser radiation at λ = 405.9 nm leads to modification of optical properties of nanocomposite. For this exposed area there is a significant amount of photodynamic changes under subsequent exposure to laser radiation at λ = 405.9 nm, namely photoabsorption and photorefraction which were studied at λ = 633 nm. The value of these effects dependent on the concentration of quantum dots and modifying radiation parameters. Moreover, it has dependence from polarization of exposure radiation.

Pressure-Induced Amorphization and a New High Density Amorphous Metallic Phase in Matrix-Free Ge Nanoparticles.

PubMed

Corsini, Niccolo R C; Zhang, Yuanpeng; Little, William R; Karatutlu, Ali; Ersoy, Osman; Haynes, Peter D; Molteni, Carla; Hine, Nicholas D M; Hernandez, Ignacio; Gonzalez, Jesus; Rodriguez, Fernando; Brazhkin, Vadim V; Sapelkin, Andrei

2015-11-11

Over the last two decades, it has been demonstrated that size effects have significant consequences for the atomic arrangements and phase behavior of matter under extreme pressure. Furthermore, it has been shown that an understanding of how size affects critical pressure-temperature conditions provides vital guidance in the search for materials with novel properties. Here, we report on the remarkable behavior of small (under ~5 nm) matrix-free Ge nanoparticles under hydrostatic compression that is drastically different from both larger nanoparticles and bulk Ge. We discover that the application of pressure drives surface-induced amorphization leading to Ge-Ge bond overcompression and eventually to a polyamorphic semiconductor-to-metal transformation. A combination of spectroscopic techniques together with ab initio simulations were employed to reveal the details of the transformation mechanism into a new high density phase-amorphous metallic Ge.

Matrix metalloproteinases-2 and -9 in Campylobacter jejuni-induced paralytic neuropathy resembling Guillain-Barré syndrome in chickens.

PubMed

Nyati, Kishan Kumar; Prasad, Kashi Nath; Agrawal, Vinita; Husain, Nuzhat

2017-10-01

Inflammation in Guillain-Barré syndrome (GBS) is manifested by changes in matrix metalloproteinase (MMP) and pro-inflammatory cytokine expression. We investigated the expression of MMP-2, -9 and TNF-α and correlated it with pathological changes in sciatic nerve tissue from Campylobacter jejuni-induced chicken model for GBS. Campylobacter jejuni and placebo were fed to chickens and assessed for disease symptoms. Sciatic nerves were examined by histopathology and immunohistochemistry. Expressions of MMPs and TNF-α, were determined by real-time PCR, and activities of MMPs by zymography. Diarrhea developed in 73.3% chickens after infection and 60.0% of them developed GBS like neuropathy. Pathology in sciatic nerves showed perinodal and/or patchy demyelination, perivascular focal lymphocytic infiltration and myelin swelling on 10th- 20th post infection day (PID). MMP-2, -9 and TNF-α were up-regulated in progressive phase of the disease. Enhanced MMP-2, -9 and TNF-α production in progressive phase correlated with sciatic nerve pathology in C. jejuni-induced GBS chicken model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Swelling-induced optical anisotropy of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate): deswelling kinetics probed by quantitative Mueller matrix polarimetry.

PubMed

Patil, Nagaraj; Soni, Jalpa; Ghosh, Nirmalya; De, Priyadarsi

2012-11-29

Thermodynamically favored polymer-water interactions below the lower critical solution temperature (LCST) caused swelling-induced optical anisotropy (linear retardance) of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate). This was exploited to study the macroscopic deswelling kinetics quantitatively by a generalized polarimetry analysis method, based on measurement of the Mueller matrix and its subsequent inverse analysis via the polar decomposition approach. The derived medium polarization parameters, namely, linear retardance (δ), diattenuation (d), and depolarization coefficient (Δ), of the hydrogels showed interesting differences between the gels prepared by conventional free radical polymerization (FRP) and reversible addition-fragmentation chain transfer polymerization (RAFT) and also between dry and swollen state. The effect of temperature, cross-linking density, and polymerization technique employed to synthesize hydrogel on deswelling kinetics was systematically studied via conventional gravimetry and corroborated further with the corresponding Mueller matrix derived quantitative polarimetry characteristics (δ, d, and Δ). The RAFT gels exhibited higher swelling ratio and swelling-induced optical anisotropy compared to FRP gels and also deswelled faster at 30 °C. On the contrary, at 45 °C, deswelling was significantly retarded for the RAFT gels due to formation of a skin layer, which was confirmed and quantified via the enhanced diattenuation and depolarization parameters.

Application of Laser Induced Breakdown Spectroscopy to Monitor Rare Earth Ions in Glass Matrix

NASA Astrophysics Data System (ADS)

Sharma, Prakash; Carter, Michael; Kumar, Akshaya

2013-05-01

The Laser Induced breakdown spectroscopy (LIBS) is a real time online technique that can be used to monitor the concentration of rare earth ions in amorphous glass matrix. This study has significant application in the glass industry where the composition of the glass can be monitored in real time using LIBS technology for quality control. The Eu3 + ions doped silicate glasses were developed via sol gel method. The glasses of varying molar percentages of Eu3 + (0.02, 0.05 and 0.08 mole percent), were prepared to study the effect of variation in concentration of Eu3 + ions on the LIBS signal and to calculate its limit of detection (LOD). The spectral assignment of the observed LIBS spectrum has been made. In order to find the maximum signal to noise ratio, we also recorded the intensity of LIBS signal for various integration start delay (ISD) time at a constant power of (pulsed Nd: YAG) laser. The ocean optics LIBS 2500plus spectrometer along with a Q switched Nd:YAG laser (Quantel, Big Sky) were used to record the LIBS spectrum.

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

Jenny, Matthew J.; Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487; Aluru, Neelakanteswar

development. -- Highlights: ► Zebrafish embryos were exposed to TCDD at two different developmental timepoints. ► Compared different methods in detecting global changes in microRNA expression. ► TCDD caused significant changes in microRNA expression in zebrafish embryos. ► Differentially expressed microRNAs have roles related to TCDD-induced phenotypes.« less

In utero and lactational exposure of male rats to 2,3,7,8-tetrachlorodibenzo-p-dioxin. 3. Effects on spermatogenesis and reproductive capability.

PubMed

Mably, T A; Bjerke, D L; Moore, R W; Gendron-Fitzpatrick, A; Peterson, R E

1992-05-01

reserves caused by perinatal TCDD exposure since rats produce and ejaculate far more sperm than are required for normal fertility. The TCDD-induced reduction in spermatogenesis cannot be accounted for by concurrent effects on plasma follicle-stimulating hormone or androgen concentrations or by undernutrition. To investigate the nature of the spermatogenic lesion, leptotene spermatocyte to Sertoli cell ratios were determined.(ABSTRACT TRUNCATED AT 400 WORDS)

Transplantation of transduced chondrocytes protects articular cartilage from interleukin 1-induced extracellular matrix degradation.

PubMed Central

Baragi, V M; Renkiewicz, R R; Jordan, H; Bonadio, J; Hartman, J W; Roessler, B J

1995-01-01

Gene therapy used in the context of delivering a therapeutic gene(s) to chondrocytes offers a new approach for treating chondrocyte-mediated cartilage degradation associated with various human arthropathies including osteoarthritis. In this study, gene delivery to human osteoarthritis chondrocytes in monolayer culture was demonstrated using two adenoviral vectors (Ad.CMVlacZ and Ad.RSVntlacZ) carrying the Escherichia coli beta-galactosidase marker gene, and a third vector (Ad.RSV hIL-1ra) containing the cDNA for human interleukin-1 receptor antagonist. At an moi of 10(3) plaque-forming units/chondrocyte, > 90% of the infected cells stained positive for E. coli beta-galactosidase activity, indicating a high efficiency of transduction. Genetically modified chondrocytes were then transplanted onto the articular surface of osteoarthritic cartilage organ cultures with and without the underlying subchondral bone. Both in situ staining of the cartilage organ cultures for E. coli beta-galactosidase activity and examination by scanning electron microscopy indicated that the transplanted chondrocytes adhered and integrated into the articular surface and continued to express transgenic protein. Chondrocytes transduced with Ad.RSV hIL-1ra and seeded onto the surface of osteoarthritic cartilage secreted high levels of biologically active IL-1 receptor antagonist. The Ad.RSV hIL-1ra-treated cartilage samples were resistant to IL1-induced proteoglycan degradation over 10 d of sustained organ culture. These data demonstrate that transplantation of transduced chondrocytes onto the articular surface protects cartilage from IL-1-induced extracellular matrix degradation. Images PMID:7593634

Polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in fishes from Saginaw Bay, Michigan

USGS Publications Warehouse

Giesy, John P.; Jude, David J.; Tillitt, Donald E.; Gale, Robert W.; Meadows, John C.; Zajieck, James L.; Peterman, Paul H.; Verbrugge, David A.; Sanderson, J. Thomas; Schwartz, Ted R.; Tuchman, Marc L.

1997-01-01

Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated naphthalenes (PCNs), polychlorinated dibenzothiophenes (PCDTs), and 2,3,7,8-tetrachlo-rodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents were measured in composite samples of forage fishes and several sizes of walleyes (Stizostedion vitreum) and common carp (Cyprinus carpio) collected from Saginaw Bay, Michigan, USA. The concentrations of 2,3,7,8-TCDD equivalents determined from the use of TCDD equivalency factors (TEFs) and instrumentally determined concentrations of individual congeners were designated TEq. The 2,3,7,8-TCDD equivalents determined on the same extracts with the H4IIE bioassay were defined as TCDD-EQ. Concentrations of TCDD-EQ and TEq were significantly, but poorly correlated (R2 = 0.44). Concentrations of TCDD-EQ and TEq ranged from 10.6 to 348 and 13.5 to 69.5 ng/kg, wet weight, respectively. The ratio of TCDD-EQ to TEq ranged from 0.5 to 5.0, with the greatest ratio observed in common carp but the average ratio between TEq and TCDD-EQ was approximately 1.0. In common carp, larger walleye, and medium-sized alewife (Alosa pseudoharengus) there were significant concentrations of TCDD-EQ that could not be accounted for by TEq calculated from an additive model of PCBs, PCDDs, or PCDFs. As much as 75% of the TCDD-EQ in some samples could not be accounted for by TEqs. It is unlikely that PCNs, PCDTs, or polychlorinated diphenyl ethers (PCDEs) occurred at concentrations that were, based on their relative potencies, great enough to contribute significant quantities of TCDD-EQ. The discrepency between TCDD-EQs and TEqs was not due to antagonisms among congeners or extraction efficiencies.

Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations

PubMed Central

Najbauer, Eszter E.; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

2018-01-01

The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, 6 conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-live of (3.7±0.5)·103 s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser induced conversions revealed that the excitation of the stretching overtone of both the side-chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations. PMID:26201050

Oriented nanofibers embedded in a polymer matrix

NASA Technical Reports Server (NTRS)

Barrera, Enrique V. (Inventor); Lozano, Karen (Inventor); Rodriguez-Macias, Fernando J. (Inventor); Chibante, Luis Paulo Felipe (Inventor); Stewart, David Harris (Inventor)

2011-01-01

A method of forming a composite of embedded nanofibers in a polymer matrix is disclosed. The method includes incorporating nanofibers in a plastic matrix forming agglomerates, and uniformly distributing the nanofibers by exposing the agglomerates to hydrodynamic stresses. The hydrodynamic said stresses force the agglomerates to break apart. In combination or additionally elongational flow is used to achieve small diameters and alignment. A nanofiber reinforced polymer composite system is disclosed. The system includes a plurality of nanofibers that are embedded in polymer matrices in micron size fibers. A method for producing nanotube continuous fibers is disclosed. Nanofibers are fibrils with diameters of 100 nm, multiwall nanotubes, single wall nanotubes and their various functionalized and derivatized forms. The method includes mixing a nanofiber in a polymer; and inducing an orientation of the nanofibers that enables the nanofibers to be used to enhance mechanical, thermal and electrical properties. Orientation is induced by high shear mixing and elongational flow, singly or in combination. The polymer may be removed from said nanofibers, leaving micron size fibers of aligned nanofibers.

Defining the Borders of Dose Addition: Mixture Effects of 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Dibutyl phthalate on Male Rat Reproductive Tract Development

EPA Science Inventory

In utero exposure to either dibutyl phthalate (DBP) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) disrupts male rat reproductive tract differentiation. However, they act via different modes of toxicity and induce distinct postnatal phenotypes. DBP exposure decreases anogenital di...

The infrared spectrum of matrix isolated hydrogen and deuterium

NASA Technical Reports Server (NTRS)

Warren, J. A.; Smith, G. R.; Guillory, W. A.

1980-01-01

The induced infrared spectra of H2 and D2, trapped in matrices of Ar, Kr, N2, CO, have been investigated. It is found that in Ar and Kr, the pure rotation spectrum is always readily observable. Portions of the fundamental region, however, are induced by impurities, while the entire spectrum is impurity induced in N2 matrices. These results are discussed in light of a recent Raman study of this system, and in comparison with several single crystal studies. Effective rotational and vibrational constants for matrix isolated H2 are also given.

Membrane Type 1–Matrix Metalloproteinase/Akt Signaling Axis Modulates TNF-α-Induced Procoagulant Activity and Apoptosis in Endothelial Cells

PubMed Central

Ohkawara, Hiroshi; Ishibashi, Toshiyuki; Sugimoto, Koichi; Ikeda, Kazuhiko; Ogawa, Kazuei; Takeishi, Yasuchika

2014-01-01

Membrane type 1–matrix metalloproteinase (MT1-MMP) functions as a signaling molecule in addition to a proteolytic enzyme. Our hypothesis was that MT1-MMP cooperates with protein kinase B (Akt) in tumor necrosis factor (TNF)-α-induced signaling pathways of vascular responses, including tissue factor (TF) procoagulant activity and endothelial apoptosis, in cultured human aortic endothelial cells (ECs). TNF-α (10 ng/mL) induced a decrease in Akt phosphorylation within 60 minutes in ECs. A chemical inhibitor of MMP, TIMP-2 and selective small interfering RNA (siRNA)-mediated suppression of MT1-MMP reversed TNF-α-triggered transient decrease of Akt phosphorylation within 60 minutes, suggesting that MT1-MMP may be a key regulator of Akt phosphorylation in TNF-α-stimulated ECs. In the downstream events, TNF-α increased TF antigen and activity, and suppressed the expression of thrombomodulin (TM) antigen. Inhibition of Akt markedly enhanced TNF-α-induced expression of TF antigen and activity, and further reduced the expression of TM antigen. Silencing of MT1-MMP by siRNA also reversed the changed expression of TF and TM induced by TNF-α. Moreover, TNF-α induced apoptosis of ECs through Akt- and forkhead box protein O1 (FoxO1)-dependent signaling pathway and nuclear factor-kB (NF-kB) activation. Knockdown of MT1-MMP by siRNA reversed apoptosis of ECs by inhibiting TNF-α-induced Akt-dependent regulation of FoxO1 in TNF-α-stimulated ECs. Immunoprecipitation demonstrated that TNF-α induced the changes in the associations between the cytoplasmic fraction of MT1-MMP and Akt in ECs. In conclusion, we show new evidence that MT1-MMP/Akt signaling axis is a key modifier for TNF-α-induced signaling pathways for modulation of procoagulant activity and apoptosis of ECs. PMID:25162582

Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Gyekanyesi, John (Technical Monitor); Liaw, Benjamin; Villars, Esther; Delmont, Frantz

2003-01-01

The main objective of this NASA Faculty Awards for Research (FAR) project is to conduct ultrasonic assessment of impact-induced damage and microcracking in fiber-metal laminated (FML) composites at various temperatures. It is believed that the proposed study of impact damage assessment on FML composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Impact-induced damage mechanisms in GLARE and ARALL fiber-metal laminates subject to instrumented drop-weight impacts at various temperatures were studied. GLARE and ARALL are hybrid composites made of alternating layers of aluminum and glass- (for GLARE) and aramid- (for ARALL) fiber reinforced epoxy. Damage in pure aluminum panels impacted by foreign objects was mainly characterized by large plastic deformation surrounding a deep penetration dent. On the other hand, plastic deformation in fiber-metal laminates was often not as severe although the penetration dent was still produced. The more stiff fiber-reinforced epoxy layers provided better bending rigidity; thus, enhancing impact damage tolerance. Severe cracking, however, occurred due to the use of these more brittle fiber-reinforced epoxy layers. Fracture patterns, e.g., crack length and delamination size, were greatly affected by the lay-up configuration rather than by the number of layers, which implies that thickness effect was not significant for the panels tested in this study. Immersion ultrasound techniques were then used to assess damages generated by instrumented drop-weight impacts onto these fiber-metal laminate panels as well as 2024-T3 aluminum/cast acrylic sandwich plates adhered by epoxy. Depending on several parameters, such as impact velocity, mass, temperature, laminate configuration, sandwich construction, etc., various types of impact damage were observed, including plastic deformation, radiating

Synergistic effects of tributyltin and 2,3,7,8-tetrachlorodibenzo-p-dioxin on differentiating osteoblasts and osteoclasts.

PubMed

Koskela, Antti; Viluksela, Matti; Keinänen, Meeri; Tuukkanen, Juha; Korkalainen, Merja

2012-09-01

The purpose of this study was to examine the effects of the persistent and accumulative environmental pollutants tributyltin (TBT) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) individually and in combination on differentiating bone cells. TBT and TCDD are chemically distinct compounds with different mechanisms of toxicity, but they typically have the same sources of exposure and both have been shown to affect bone development at low exposure levels. Bone marrow stem cells were isolated from femurs and tibias of C57BL/6J mice, differentiated in culture into osteoblasts or osteoclasts and exposed to 0.1-10nM TBT, 0.01-1nM TCDD or 10nM TBT+ 1nM TCDD. In osteoblasts, the combined exposure to TBT and TCDD significantly decreased the mRNA expression of alkaline phosphatase and osteocalcin more than TBT or TCDD alone. PCR array showed different gene expression profiles for TBT and TCDD individually, and the combination evoked several additional alterations in gene expression. Expression of aryl hydrocarbon receptor repressor (AHRR) was increased by TCDD as expected, but simultaneous exposure to TBT prevented the increase thus potentially strengthening AHR-mediated effects of TCDD. The number of osteoclasts was reduced by TCDD alone and in combination with TBT, but TBT alone had no effect. However, the total area of resorbed bone was remarkably lower after combined exposure than after TBT or TCDD alone. In conclusion, very low concentrations of TBT and TCDD have synergistic deleterious effects on bone formation and additive effects on bone resorption. Copyright © 2012 Elsevier Inc. All rights reserved.

Thyroid Hormone Induces Apoptosis in Primary Cell Cultures of Tadpole Intestine: Cell Type Specificity and Effects of Extracellular Matrix

PubMed Central

Su, Yuan; Shi, Yufang; Stolow, Melissa A.; Shi, Yun-Bo

1997-01-01

Thyroid hormone (T3 or 3,5,3′-triiodothyronine) plays a causative role during amphibian metamorphosis. To investigate how T3 induces some cells to die and others to proliferate and differentiate during this process, we have chosen the model system of intestinal remodeling, which involves apoptotic degeneration of larval epithelial cells and proliferation and differentiation of other cells, such as the fibroblasts and adult epithelial cells, to form the adult intestine. We have established in vitro culture conditions for intestinal epithelial cells and fibroblasts. With this system, we show that T3 can enhance the proliferation of both cell types. However, T3 also concurrently induces larval epithelial apoptosis, which can be inhibited by the extracellular matrix (ECM). Our studies with known inhibitors of mammalian cell death reveal both similarities and differences between amphibian and mammalian cell death. These, together with gene expression analysis, reveal that T3 appears to simultaneously induce different pathways that lead to specific gene regulation, proliferation, and apoptotic degeneration of the epithelial cells. Thus, our data provide an important molecular and cellular basis for the differential responses of different cell types to the endogenous T3 during metamorphosis and support a role of ECM during frog metamorphosis. PMID:9396758

Fiber pushout and interfacial shear in metal-matrix composites

NASA Technical Reports Server (NTRS)

Koss, Donald A.; Hellmann, John R.; Kallas, M. N.

1993-01-01

Recent thin-slice pushout tests have suggested that MMC matrix-fiber interface failure processes depend not only on such intrinsic factors as bond strength and toughness, and matrix plasticity, but such extrinsic factors as specimen configuration, thermally-induced residual stresses, and the mechanics associated with a given test. After detailing the contrasts in fiber-pullout and fiber-pushout mechanics, attention is given to selected aspects of thin-slice fiber pushout behavior illustrative of the physical nature of interfacial shear response and its dependence on both intrinsic and extrinsic factors.

Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization.

PubMed

Lee, Chuping; Lu, I-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

2016-09-01

In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser. Graphical Abstract ᅟ.

Quantitative methods for compensation of matrix effects and self-absorption in Laser Induced Breakdown Spectroscopy signals of solids

NASA Astrophysics Data System (ADS)

Takahashi, Tomoko; Thornton, Blair

2017-12-01

This paper reviews methods to compensate for matrix effects and self-absorption during quantitative analysis of compositions of solids measured using Laser Induced Breakdown Spectroscopy (LIBS) and their applications to in-situ analysis. Methods to reduce matrix and self-absorption effects on calibration curves are first introduced. The conditions where calibration curves are applicable to quantification of compositions of solid samples and their limitations are discussed. While calibration-free LIBS (CF-LIBS), which corrects matrix effects theoretically based on the Boltzmann distribution law and Saha equation, has been applied in a number of studies, requirements need to be satisfied for the calculation of chemical compositions to be valid. Also, peaks of all elements contained in the target need to be detected, which is a bottleneck for in-situ analysis of unknown materials. Multivariate analysis techniques are gaining momentum in LIBS analysis. Among the available techniques, principal component regression (PCR) analysis and partial least squares (PLS) regression analysis, which can extract related information to compositions from all spectral data, are widely established methods and have been applied to various fields including in-situ applications in air and for planetary explorations. Artificial neural networks (ANNs), where non-linear effects can be modelled, have also been investigated as a quantitative method and their applications are introduced. The ability to make quantitative estimates based on LIBS signals is seen as a key element for the technique to gain wider acceptance as an analytical method, especially in in-situ applications. In order to accelerate this process, it is recommended that the accuracy should be described using common figures of merit which express the overall normalised accuracy, such as the normalised root mean square errors (NRMSEs), when comparing the accuracy obtained from different setups and analytical methods.

In vitro endocrine disruption and TCDD-like effects of three novel brominated flame retardants: TBPH, TBB, & TBCO.

PubMed

Saunders, David M V; Higley, Eric B; Hecker, Markus; Mankidy, Rishikesh; Giesy, John P

2013-11-25

The novel brominated flame retardants (NBFRs), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), Bis(2-ethylhexyl)-2,3,4,5-tetrabromophtalate (TBPH), and 1,2,5,6-tetrabromocyclooctane (TBCO) are components of flame retardant mixtures including Firemaster 550 and Saytex BC-48. Despite the detection of these NBFRs in environmental and biotic matrices, studies regarding their toxicological effects are poorly represented in the literature. The present study examined endocrine disruption by these three NBFRs using the yeast YES/YAS reporter assay and the mammalian H295R steroidogenesis assay. Activation of the aryl hydrocarbon receptor (AhR) was also assessed using the H4IIE reporter assay. The NBFRs produced no TCDD-like effects in the H4IIE assay or agonistic effects in the YES/YAS assays. TBB produced a maximal antiestrogenic effect of 62% at 0.5mgL(-1) in the YES assay while TBPH and TBCO produced maximal antiandrogenic effects of 74% and 59% at 300mgL(-1) and 1500mgL(-1), respectively, in the YAS assay. Significant effects were also observed in the H295R assay. At 0.05mgL(-1), 15mgL(-1), and 15mgL(-1) TBB, TBPH, and TBCO exposures, respectively resulted in a 2.8-fold, 5.4-fold, and 3.3-fold increase in concentrations of E2. This is one of the first studies to demonstrate the in vitro endocrine disrupting potentials of TBB, TBPH, and TBCO. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

FAP-overexpressing fibroblasts produce an extracellular matrix that enhances invasive velocity and directionality of pancreatic cancer cells

PubMed Central

2011-01-01

Background Alterations towards a permissive stromal microenvironment provide important cues for tumor growth, invasion, and metastasis. In this study, Fibroblast activation protein (FAP), a serine protease selectively produced by tumor-associated fibroblasts in over 90% of epithelial tumors, was used as a platform for studying tumor-stromal interactions. We tested the hypothesis that FAP enzymatic activity locally modifies stromal ECM (extracellular matrix) components thus facilitating the formation of a permissive microenvironment promoting tumor invasion in human pancreatic cancer. Methods We generated a tetracycline-inducible FAP overexpressing fibroblastic cell line to synthesize an in vivo-like 3-dimensional (3D) matrix system which was utilized as a stromal landscape for studying matrix-induced cancer cell behaviors. A FAP-dependent topographical and compositional alteration of the ECM was characterized by measuring the relative orientation angles of fibronectin fibers and by Western blot analyses. The role of FAP in the matrix-induced permissive tumor behavior was assessed in Panc-1 cells in assorted matrices by time-lapse acquisition assays. Also, FAP+ matrix-induced regulatory molecules in cancer cells were determined by Western blot analyses. Results We observed that FAP remodels the ECM through modulating protein levels, as well as through increasing levels of fibronectin and collagen fiber organization. FAP-dependent architectural/compositional alterations of the ECM promote tumor invasion along characteristic parallel fiber orientations, as demonstrated by enhanced directionality and velocity of pancreatic cancer cells on FAP+ matrices. This phenotype can be reversed by inhibition of FAP enzymatic activity during matrix production resulting in the disorganization of the ECM and impeded tumor invasion. We also report that the FAP+ matrix-induced tumor invasion phenotype is β1-integrin/FAK mediated. Conclusion Cancer cell invasiveness can be affected by

Conformational isomerism of pyridoxal. Infrared matrix isolation and theoretical studies.

PubMed

Kwiatek, Anna; Mielke, Zofia

2015-01-25

A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(2p,2d) study of pyridoxal was performed. The calculations resulted in five stable PLHB conformers stabilized by intramolecular O-H⋯O bonding between phenolic OH and carbonyl C=O groups and another thirteen conformers in which OH or/and aldehyde groups are rotated by 180° around CO or/and CC bonds leading, respectively, to formation of PLO, PLA and PLOA conformers. The analysis of the spectra of the as-deposited matrix indicated that two most stable PLHB1 and PLHB2 conformers with intramolecular hydrogen bond are present in the matrix. The exposure of the PL/Ar matrix to mercury lamp radiation (λ>345 nm) induced conformational change of PLHB isomers to PLOA ones. Copyright © 2014 Elsevier B.V. All rights reserved.

An Aryl Hydrocarbon Receptor from the Salamander Ambystoma mexicanum Exhibits Low Sensitivity to 2,3,7,8-Tetrachlorodibenzo-p-dioxin.

PubMed

Shoots, Jenny; Fraccalvieri, Domenico; Franks, Diana G; Denison, Michael S; Hahn, Mark E; Bonati, Laura; Powell, Wade H

2015-06-02

Structural features of the aryl hydrocarbon receptor (AHR) can underlie species- and population-specific differences in its affinity for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). These differences often explain variations in TCDD toxicity. Frogs are relatively insensitive to dioxin, and Xenopus AHRs bind TCDD with low affinity. Weak TCDD binding results from the combination of three residues in the ligand-binding domain: A354 and A370, and N325. Here we sought to determine whether this mechanism of weak TCDD binding is shared by other amphibian AHRs. We isolated an AHR cDNA from the Mexican axolotl (Ambystoma mexicanum). The encoded polypeptide contains identical residues at positions that confer low TCDD affinity to X. laevis AHRs (A364, A380, and N335), and homology modeling predicts they protrude into the binding cavity. Axolotl AHR bound one-tenth the TCDD of mouse AHR in velocity sedimentation analysis, and in transactivation assays, the EC50 for TCDD was 23 nM, similar to X. laevis AHR1β (27 nM) and greater than AHR containing the mouse ligand-binding domain (0.08 nM). Sequence, modeled structure, and function indicate that axolotl AHR binds TCDD weakly, predicting that A. mexicanum lacks sensitivity toTCDD toxicity. We hypothesize that this characteristic of axolotl and Xenopus AHRs arose in a common ancestor of the Caudata and Anura.

Analysis of delamination in cross-ply laminates initiating from impact induced matrix cracking

NASA Technical Reports Server (NTRS)

Salpekar, S. A.

1993-01-01

Two-dimensional finite element analyses of (02/90(8)/02) glass/epoxy and graphite/epoxy composite laminates were performed to investigate some of the characteristics of damage development due to an impact load. A cross section through the thickness of the laminate with fixed ends, and carrying a transverse load in the center, was analyzed. Inclined matrix cracks, such as those produced by a low-velocity impact, were modeled in the 90 deg ply group. The introduction of the matrix cracks caused large interlaminar tensile and shear stresses in the vicinity of both crack tips in the 0/90 and 90/0 interfaces, indicating that matrix cracking may give rise to delamination. The ratio of Mode I to total strain energy release rate, G(I)/G(total), at the beginning of delamination, calculated at the two (top and bottom) matrix crack tips was 60 and 28 percent, respectively, in the glass/epoxy laminate. The corresponding ratio was 97 and 77 percent in the graphite/epoxy laminate. Thus, a significant Mode I component of strain energy release rate may be present at the delamination initiation due to an impact load. The value of strain energy release rate at either crack tip increased due to an increase in the delamination length at the other crack tip and may give rise to an unstable delamination growth under constant load.

Influence of irradiation on the osteoinductive potential of demineralized bone matrix.

PubMed

Wientroub, S; Reddi, A H

1988-04-01

Samples of demineralized bone matrix (DBM) were exposed to graduated doses of radiation (1-15 Megarad) (Mrad) utilizing a linear accelerator and then implanted into the thoracic region of Long-Evans rats. Subcutaneous implantation of DBM into allogenic rats induces endochondral bone. In response to matrix implantation, a cascade of events ensues; mesenchymal cell proliferation on day 3 postimplantation, chondrogenesis on day 7, calcification of the cartilagenous matrix and chondrolysis on day 9, and osteogenesis on day 11 resulting in formation of an ossicle containing active hemopoietic tissue. Bone formation was assessed by measuring alkaline phosphatase activity, the rate of mineralization was determined by measuring 45Ca incorporation to bone mineral, and 40Ca content measured the extent of mineralization; acid phosphatase activity was used as a parameter for bone resorption. The dose of radiation (2.5 Mrad) currently used by bone banks for sterilization of bone tissue did not destroy the bone induction properties of DBM. Furthermore, radiation of 3-5 Mrad even enhanced bone induction, insofar as it produced more bone at the same interval of time than was obtained from unirradiated control samples. None of the radiation doses used in these experiments abolished bone induction, although the response induced by matrix irradiated with doses higher than 5 Mrad was delayed.

Effects of rosuvastatin on the production and activation of matrix metalloproteinase-2 and migration of cultured rat vascular smooth muscle cells induced by homocysteine.

PubMed

Shi, Ya-fei; Chi, Ju-fang; Tang, Wei-liang; Xu, Fu-kang; Liu, Long-bin; Ji, Zheng; Lv, Hai-tao; Guo, Hang-yuan

2013-08-01

To test the influence of homocysteine on the production and activation of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) and on cell migration of cultured rat vascular smooth muscle cells (VSMCs). Also, to explore whether rosuvastatin can alter the abnormal secretion and activation of MMP-2 and TIMP-2 and migration of VSMCs induced by homocysteine. Rat VSMCs were incubated with different concentrations of homocysteine (50-5000 μmol/L). Western blotting and gelatin zymography were used to investigate the expressions and activities of MMP-2 and TIMP-2 in VSMCs in culture medium when induced with homocysteine for 24, 48, and 72 h. Transwell chambers were employed to test the migratory ability of VSMCs when incubated with homocysteine for 48 h. Different concentrations of rosuvastatin (10(-9)-10(-5) mol/L) were added when VSMCs were induced with 1000 μmol/L homocysteine. The expressions and activities of MMP-2 and TIMP-2 were examined after incubating for 24, 48, and 72 h, and the migration of VSMCs was also examined after incubating for 48 h. Homocysteine (50-1000 μmol/L) increased the production and activation of MMP-2 and expression of TIMP-2 in a dose-dependent manner. However, when incubated with 5000 μmol/L homocysteine, the expression of MMP-2 was up-regulated, but its activity was down-regulated. Increased homocysteine-induced production and activation of MMP-2 were reduced by rosuvastatin in a dose-dependent manner whereas secretion of TIMP-2 was not significantly altered by rosuvastatin. Homocysteine (50-5000 μmol/L) stimulated the migration of VSMCs in a dose-dependent manner, but this effect was eliminated by rosuvastatin. Homocysteine (50-1000 μmol/L) significantly increased the production and activation of MMP-2, the expression of TIMP-2, and the migration of VSMCs in a dose-dependent manner. Additional extracellular rosuvastatin can decrease the excessive expression and activation of MMP-2 and

Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines

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

Vorrink, Sabine U.; Department of Radiation Oncology, The University of Iowa, Iowa City, IA; Severson, Paul L.

2014-02-01

The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degreesmore » of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126). Exposure to 1% O{sub 2} prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity. - Highlights: • Significant crosstalk exists between AhR and HIF-1α signaling. • Hypoxia perturbs PCB 126 induced Ah

Immunohistochemical evidence of rapid extracellular matrix remodeling after iron-particle irradiation of mouse mammary gland

NASA Technical Reports Server (NTRS)

Ehrhart, E. J.; Gillette, E. L.; Barcellos-Hoff, M. H.; Chaterjee, A. (Principal Investigator)

1996-01-01

High-LET radiation has unique physical and biological properties compared to sparsely ionizing radiation. Recent studies demonstrate that sparsely ionizing radiation rapidly alters the pattern of extracellular matrix expression in several tissues, but little is known about the effect of heavy-ion radiation. This study investigates densely ionizing radiation-induced changes in extracellular matrix localization in the mammary glands of adult female BALB/c mice after whole-body irradiation with 0.8 Gy 600 MeV iron particles. The basement membrane and interstitial extracellular matrix proteins of the mammary gland stroma were mapped with respect to time postirradiation using immunofluorescence. Collagen III was induced in the adipose stroma within 1 day, continued to increase through day 9 and was resolved by day 14. Immunoreactive tenascin was induced in the epithelium by day 1, was evident at the epithelial-stromal interface by day 5-9 and persisted as a condensed layer beneath the basement membrane through day 14. These findings parallel similar changes induced by gamma irradiation but demonstrate different onset and chronicity. In contrast, the integrity of epithelial basement membrane, which was unaffected by sparsely ionizing radiation, was disrupted by iron-particle irradiation. Laminin immunoreactivity was mildly irregular at 1 h postirradiation and showed discontinuities and thickening from days 1 to 9. Continuity was restored by day 14. Thus high-LET radiation, like sparsely ionizing radiation, induces rapid-remodeling of the stromal extracellular matrix but also appears to alter the integrity of the epithelial basement membrane, which is an important regulator of epithelial cell proliferation and differentiation.

Ferulic acid, a phenolic phytochemical, inhibits UVB-induced matrix metalloproteinases in mouse skin via posttranslational mechanisms.

PubMed

Staniforth, Vanisree; Huang, Wen-Ching; Aravindaram, Kandan; Yang, Ning-Sun

2012-05-01

Matrix metalloproteinases MMP-2 and -9 are known to be overexpressed in ultraviolet B (UVB)-irradiated skin tissues and contribute to the acceleration of photoaging and the development of skin cancer. But the specific molecular mechanisms that can control or interfere with the expression and regulation of these MMP-2 and -9 activities in skin are not clearly understood. The aim of the present study was to analyze the suppressive effects of ferulic acid (FA), an abundant phenolic compound present in various dietary and medicinal plants, on UVB radiation-induced MMP-2 and -9 activities in mouse skin. For attenuation of chronic UVB irradiation damage to skin, inhibition of MMP-2 and -9 protein expression was detected using immunohistochemistry analysis. However, the in situ suppressive effects of FA did not interfere with the transcription or translation of MMP-2 and -9, suggesting that its action could be mediated via the proteasome pathway. Histological analyses showed that FA attenuates the degradation of collagen fibers, abnormal accumulation of elastic fibers and epidermal hyperplasia induced by UVB, demonstrating the functional and physiological relevance of FA effects in UVB-irradiated skin tissues. Together, our findings provide a novel and increased insight into the in vivo action of FA and suggest a possible clinical application in skin pathophysiological conditions associated with overexpression of MMP-2 and -9. Copyright © 2012 Elsevier Inc. All rights reserved.

Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

PubMed

Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

2017-09-01

Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

Effects of in Utero Exposure of C57BL/6J Mice to 2,3,7,8-Tetrachlorodibenzo-p-dioxin on Epidermal Permeability Barrier Development and Function

PubMed Central

Muenyi, Clarisse S.; Carrion, Sandra Leon; Jones, Lynn A.; Kennedy, Lawrence H.; Slominski, Andrzej T.

2014-01-01

Background: Development of the epidermal permeability barrier (EPB) is essential for neonatal life. Defects in this barrier are found in many skin diseases such as atopic dermatitis. Objective: We investigated the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the development and function of the EPB. Methods: Timed-pregnant C57BL/6J mice were gavaged with corn oil or TCDD (10 μg/kg body weight) on gestation day 12. Embryos were harvested on embryonic day (E) 15, E16, E17, and postnatal day (PND) 1. Results: A skin permeability assay showed that TCDD accelerated the development of the EPB, beginning at E15. This was accompanied by a significant decrease in transepidermal water loss (TEWL), enhanced stratification, and formation of the stratum corneum (SC). The levels of several ceramides were significantly increased at E15 and E16. PND1 histology revealed TCDD-induced acanthosis and epidermal hyperkeratosis. This was accompanied by disrupted epidermal tight junction (TJ) function, with increased dye leakage at the terminal claudin-1–staining TJs of the stratum granulosum. Because the animals did not have enhanced rates of TEWL, a commonly observed phenotype in animals with TJ defects, we performed tape-stripping. Removal of most of the SC resulted in a significant increase in TEWL in TCDD-exposed PND1 pups compared with their control group. Conclusions: These findings demonstrate that in utero exposure to TCDD accelerates the formation of an abnormal EPB with leaky TJs, warranting further study of environmental exposures, epithelial TJ integrity, and atopic disease. Citation: Muenyi CS, Leon Carrion S, Jones LA, Kennedy LH, Slominski AT, Sutter CH, Sutter TR. 2014. Effects of in utero exposure of C57BL/6J mice to 2,3,7,8-tetrachlorodibenzo-p-dioxin on epidermal permeability barrier development and function. Environ Health Perspect 122:1052–1058; http://dx.doi.org/10.1289/ehp.1308045 PMID:24904982

Galectin-1 induces cell adhesion to the extracellular matrix and apoptosis of non-adherent human colon cancer Colo201 cells.

PubMed

Horiguchi, Natsuko; Arimoto, Kei-ichiro; Mizutani, Atsushi; Endo-Ichikawa, Yoko; Nakada, Hiroshi; Taketani, Shigeru

2003-12-01

To isolate cDNAs for molecules involved in cell adhesion to the extracellular matrix, expression cloning with non-adherent colon cancer Colo201 cells was carried out. Four positive clones were isolated and, when sequenced, one was found to be galectin-1, a beta-galactoside-binding protein. When cultured on fibronectin-, laminin-, and collagen-coated and non-coated dishes, the adherent galectin-1 cDNA-transfected Colo201 cells increased and spread somewhat. Immunofluorescence staining revealed that galectin-1 was expressed inside and outside of Colo201 cells. The adhesion was dependent on the carbohydrate-recognition domain of galectin-1 since lactose inhibited the adhesion and exogenously-added galectin-1 caused the adhesion. PD58059, an inhibitor of mitogen-activated protein kinase, or LY294002, a phosphoinositide 3-OH kinase inhibitor, decreased the adhesion. Furthermore, the expression of galectin-1 in Colo201 cells induced apoptotic cell death, while exogenously-added galectin-1 did not cause apoptosis. These results indicate that galectin-1 plays a role in both cell-matrix interactions and the inhibition of Colo201 cell proliferation, and suggest that galectin-1 expressed in cells could be associated with apoptosis.

Are calcifying matrix vesicles in atherosclerotic lesions of cellular origin?

PubMed

Bobryshev, Yuri V; Killingsworth, Murray C; Huynh, Thuan G; Lord, Reginald S A; Grabs, Anthony J; Valenzuela, Stella M

2007-03-01

Over recent years, the role of matrix vesicles in the initial stages of arterial calcification has been recognized. Matrix calcifying vesicles have been isolated from atherosclerotic arteries and the biochemical composition of calcified vesicles has been studied. No studies have yet been carried out to examine the fine structure of matrix vesicles in order to visualize the features of the consequent stages of their calcification in arteries. In the present work, a high resolution ultrastructural analysis has been employed and the study revealed that matrix vesicles in human atherosclerotic lesions are heterogeneous with two main types which we classified. Type I calcified vesicles were presented by vesicles surrounded by two electron-dense layers and these vesicles were found to be resistant to the calcification process in atherosclerotic lesions in situ. Type II matrix vesicles were presented by vesicles surrounded by several electron-dense layers and these vesicles were found to represent calcifying vesicles in atherosclerotic lesions. To test the hypothesis that calcification of matrix vesicles surrounded by multilayer sheets may occur simply as a physicochemical process, independently from the cell regulation, we produced multilamellar liposomes and induced their calcification in vitro in a manner similar to that occurring in matrix vesicles in atherosclerotic lesions in situ.

All-Arthroscopic Autologous Matrix-Induced Chondrogenesis-Aided Repair of a Patellar Cartilage Defect Using Dry Arthroscopy and a Retraction System.

PubMed

Sadlik, Boguslaw; Puszkarz, Mariusz; Kosmalska, Lidia; Wiewiorski, Martin

2017-11-01

The technique of all-arthroscopic autologous matrix-induced chondrogenesis (AMIC)-aided repair of patellar cartilage lesions using a retraction system and dry arthroscopy has been recently described. We report the first clinical and radiological data at a short-term follow-up. Twelve patients underwent AMIC-aided cartilage repair for a patellar lesion. All steps of the procedure were performed arthroscopically, which include the use of an intra-articularly placed retraction plate for distraction of the patellofemoral joint and evacuation of saline solution for collagen matrix insertion and fixation. Clinical assessment performed before surgery and at a mean follow-up time of 38 months (range: 24-70) included the following scores: Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), and visual analog scale (VAS). Magnetic resonance imaging was performed at the follow-up examination, including the magnetic resonance observation of cartilage repair tissue (MOCART) score. The mean KOOS and IKDC scores increased significantly ( p  < 0.01) from 50.3 and 37.4 points preoperatively to 90.1 and 79.4 postoperatively. The VAS score decreased from 7.8 to 2.3 points. Mean MOCART score at follow-up was 58.3 points. Cartilage repair of patellar lesions aided by a retraction system in a dry arthroscopy setup is a promising approach. Further studies are needed to evaluate this procedure and compare it to existing matrix implantation techniques. The level of evidence for the study is 4 (case series). Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Nonlinear laminate analysis for metal matrix fiber composites

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Sinclair, J. H.

1981-01-01

A nonlinear laminate analysis is described for predicting the mechanical behavior (stress-strain relationships) of angleplied laminates in which the matrix is strained nonlinearly by both the residual stress and the mechanical load and in which additional nonlinearities are induced due to progressive fiber fractures and ply relative rotations. The nonlinear laminate analysis (NLA) is based on linear composite mechanics and a piece wise linear laminate analysis to handle the nonlinear responses. Results obtained by using this nonlinear analysis on boron fiber/aluminum matrix angleplied laminates agree well with experimental data. The results shown illustrate the in situ ply stress-strain behavior and synergistic strength enhancement.

Conformers, infrared spectrum and UV-induced photochemistry of matrix-isolated furfuryl alcohol.

PubMed

Araujo-Andrade, C; Gómez-Zavaglia, A; Reva, I D; Fausto, R

2012-03-08

The infrared spectra of furfuryl alcohol (2-furanmethanol, FFA) were investigated for FFA monomers isolated in low-temperature argon matrices. The structural interpretation of the obtained experimental spectra was assisted by analysis of the molecule's conformational landscape. According to the DFT(B3LYP)/6-311++G(d,p) calculations, five different minimum energy structures were found on the potential energy surface of the molecule. They can be defined by the orientation of the OCCO and CCOH dihedral angles: GG', GG, TG, TT, GT (G = +gauche, G' = -gauche, T = trans) and have a symmetry equivalent configuration: GG' = G'G, GG = G'G', TG = TG', GT = G'T. When zero-point energies are taken into account, only three (GG', GG, and TT) out of the five unique minima correspond to stable structures. The most stable conformer GG' (OCCO, 72.7°; CCOH, -59.3°), which in gas phase at room temperature accounts for ∼65% of the total population, was the only form isolated in the argon matrices at 14 K. The other two relevant forms convert into conformer GG' during matrix deposition. The low temperature glassy and crystalline states of FFA were also obtained and their infrared spectra assigned, suggesting the sole existence of the GG' conformer also in these phases. The photochemical behavior of FFA induced in situ, by tunable UV-laser, was also studied. The longest wavelength resulting in photochemical changes in the structure of the irradiated sample was found to be λ = 229 nm. Such UV irradiation of the matrix-isolated FFA led to production of formaldehyde and different isomeric C(4)H(4)O species. Cycloprop-2-ene-1-carbaldehyde and buta-2,3-dienal (two conformers) are the main initial C(4)H(4)O photoproducts formed upon short-time excitation at λ = 229 nm. But-3-ynal (two conformers) was the principal photoproduct resulting from prolonged excitation at λ= 229 nm, being consumed upon irradiation at shorter wavelengths (λ < 227.5 nm). Vinyl ketene is produced from FFA in the

Matrix Metalloproteinase-9–Null Mice Are Resistant to TGF-β–Induced Anterior Subcapsular Cataract Formation

PubMed Central

Korol, Anna; Pino, Giuseppe; Dwivedi, Dhruva; Robertson, Jennifer V.; Deschamps, Paula A.; West-Mays, Judith A.

2015-01-01

Epithelial-mesenchymal transition (EMT) is associated with fibrotic diseases in the lens, such as anterior subcapsular cataract (ASC) formation. Often mediated by transforming growth factor (TGF)-β, EMT in the lens involves the transformation of lens epithelial cells into a multilayering of myofibroblasts, which manifest as plaques beneath the lens capsule. TGF-β–induced EMT and ASC have been associated with the up-regulation of two matrix metalloproteinases (MMPs): MMP-2 and MMP-9. The current study used MMP-2 and MMP-9 knockout (KO) mice to further determine their unique roles in TGF-β–induced ASC formation. Adenoviral injection of active TGF-β1 into the anterior chamber of all wild-type and MMP-2 KO mice led to the formation of distinct ASC plaques that were positive for α-smooth muscle actin, a marker of EMT. In contrast, only a small proportion of the MMP-9 KO eyes injected with adenovirus-expressing TGF-β1 exhibited ASC plaques. Isolated lens epithelial explants from wild-type and MMP-2 KO mice that were treated with TGF-β exhibited features indicative of EMT, whereas those from MMP-9 KO mice did not acquire a mesenchymal phenotype. MMP-9 KO mice were further bred onto a TGF-β1 transgenic mouse line that exhibits severe ASC formation, but shows a resistance to ASC formation in the absence of MMP-9. These findings suggest that MMP-9 expression is more critical than MMP-2 in mediating TGF-β–induced ASC formation. PMID:24814605

[Three-dimensional parallel collagen scaffold promotes tendon extracellular matrix formation].

PubMed

Zheng, Zefeng; Shen, Weiliang; Le, Huihui; Dai, Xuesong; Ouyang, Hongwei; Chen, Weishan

2016-03-01

To investigate the effects of three-dimensional parallel collagen scaffold on the cell shape, arrangement and extracellular matrix formation of tendon stem cells. Parallel collagen scaffold was fabricated by unidirectional freezing technique, while random collagen scaffold was fabricated by freeze-drying technique. The effects of two scaffolds on cell shape and extracellular matrix formation were investigated in vitro by seeding tendon stem/progenitor cells and in vivo by ectopic implantation. Parallel and random collagen scaffolds were produced successfully. Parallel collagen scaffold was more akin to tendon than random collagen scaffold. Tendon stem/progenitor cells were spindle-shaped and unified orientated in parallel collagen scaffold, while cells on random collagen scaffold had disorder orientation. Two weeks after ectopic implantation, cells had nearly the same orientation with the collagen substance. In parallel collagen scaffold, cells had parallel arrangement, and more spindly cells were observed. By contrast, cells in random collagen scaffold were disorder. Parallel collagen scaffold can induce cells to be in spindly and parallel arrangement, and promote parallel extracellular matrix formation; while random collagen scaffold can induce cells in random arrangement. The results indicate that parallel collagen scaffold is an ideal structure to promote tendon repairing.

Protective Effects of LSGYGP from Fish Skin Gelatin Hydrolysates on UVB-Induced MEFs by Regulation of Oxidative Stress and Matrix Metalloproteinase Activity.

PubMed