Selenium-binding protein 2, the major hepatic target for acetaminophen, shows sex differences in protein abundance

Proteomic analysis of mouse liver lesions at all three stages of Echinococcus granulosus infection

Echinococcus granulosus, a zoonotic parasite, can severely damage host health or even lead to host death. In humans, early diagnosis of E. granulosus infection is difficult because the initial stages of the infection tend to be asymptomatic, this delays treatment and worsens prognosis in most patients. Herein, we present a comprehensive, temporal proteomic atlas of the liver at three stages of E. granulosus infection and analyze the changes in the proteome of host focal lesions; this atlas may provide an overview of the effects of E. granulosus in the host, as well as the interactions between them. We identified 3,197 proteins from mice model at 1, 3, and 6 months after E. granulosus infection; of these proteins, 760 were differentially expressed (520 upregulated; 240 downregulated). Moreover, 228 differentially expressed proteins were screened through cluster analysis and classified into four clusters according to their changing trends. Subsequently, candidate molecules related to cyst invasion, growth, candidate pathways and proteins related to angiogenesis were noted to demonstrate important value in mouse liver. Next, we used western blotting to verify the presence of the aforementioned proteins in mouse liver. In the later stages, E. granulosus infection was noted to result in significant enrichment of crucial proteins facilitating protoscoleces growth and development and inhibition of amino acid and lipid metabolic enzyme expression in mouse liver; it was also noted to transform host metabolism by weakening oxidative phosphorylation and enhancing glycolysis. In conclusion, we explored the molecular mechanisms underlying the parasitic processes of E. granulosus through proteomic analysis. Our results provide evidence that may enable the exploration of core regulatory targets for early and effective diagnosis and immunotherapy of E. granulosus infection, as well as parasite-host interactions involved in cystic echinococcosis development.

Chronic Aroclor 1260 exposure alters the mouse liver proteome, selenoproteins, and metals in steatotic liver disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to increase due in part to the obesity epidemic and to environmental exposures to metabolism disrupting chemicals. A single gavage exposure of male mice to Aroclor 1260 (Ar1260), an environmentally relevant mixture of non-dioxin-like polychlorinated biphenyls (PCBs), resulted in steatohepatitis and altered RNA modifications in selenocysteine tRNA 34 weeks post-exposure. Unbiased approaches identified the liver proteome, selenoproteins, and levels of 25 metals. Ar1260 altered the abundance of 128 proteins. Enrichment analysis of the liver Ar1260 proteome included glutathione metabolism and translation of selenoproteins. Hepatic glutathione peroxidase 4 (GPX4) and Selenoprotein O (SELENOO) were increased and Selenoprotein F (SELENOF), Selenoprotein S (SELENOS), Selenium binding protein 2 (SELENBP2) were decreased with Ar1260 exposure. Increased copper, selenium (Se), and zinc and reduced iron levels were detected. These data demonstrate that Ar1260 exposure alters the (seleno)proteome, Se, and metals in MASLD-associated pathways.

The relationship between postmortem interval and protein changes in mice

Postmortem interval (PMI) estimation is important for forensic pathological autopsy. It has been reported that there is a correlation between certain protein changes in cadavers and PMI. However, no specific protein(s) has been used to determine the PMI so far. In this study, the total protein contents of mouse liver and spleen at different time of death were measured. The data showed that they were negatively correlated with the PMI. The degradation of β-actin was found to be positively correlated with the PMI in the liver. Additionally, proteomic technique was used to study the changes of protein expression related to PMI in the liver of mice. By using Two-dimensional electrophoresis, the expressions of four proteins were found to be significantly decreased and those of other three proteins were unchanged with the increase of PMI. Among the seven proteins, six were identified with peptide mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The three altered proteins were SBP2, ENOA, ALDH2 and three unchanged ones were 3HAO, TPIS, CATA, respectively. In the future, those unchanged proteins could be used as internal references to more accurately and reliably infer the time of death by assessing the level of changed proteins.

Proteomic analysis of the effect of high-fat-diet and voluntary physical activity on mouse liver

Nonalcoholic fatty liver disease (NALFD), characterized by an abnormal accumulation of triglycerides in hepatocytes, is closely linked to insulin resistance, metabolic syndrome, and changes in lipogenesis in the liver. The accumulation of hepatic lipids can lead to a range of pathologies from mild steatosis to severe cirrhosis. Endurance exercise is known to ameliorate the adverse health effects of NAFLD. Therefore, we aimed to investigate the effect of voluntary wheel running (VWR) on the metabolic changes in the livers of high-fat diet (HFD)-induced NAFLD mice and used LC-MS/MS (Liquid chromatography–mass spectrometry) to determine whether the tested intervention affected the protein expression profiles of the mouse livers. Male C57BL/6 mice were randomly divided into three groups: control (CON), high-fat diet sedentary group (HFD), high-fat diet VWR group (HFX). HFX group performed voluntary wheel running into individually cages, given a high-fat diet for 12 weeks. Food consumption, body weight, and running distance were measured every week. Using 2D (2-dimensional)-gel electrophoresis, we detected and quantitatively analyzed the protein expression with >2.0-fold change in the livers of HFD-fed mice, HFD-fed exercise (HFX) mice, and chow-fed mice. Body weight was significantly increased in HFD compared to CON (P < 0.05). The 2D-gel electrophoresis analysis indicated that there was a difference between CON and HFD groups, showing 31 increased and 27 decreased spots in the total 302 paired spots in the HFD group compared to CON. The analysis showed 43 increased and 17 decreased spots in the total 258 spots in the HFX group compared to CON. Moreover, 12 weeks of VWR showed an increase of 35 and a decrease of 8 spots in a total of 264 paired spots between HFD and HFX. LC-MS/MS of HFD group revealed that proteins involved in ketogenesis, lipid metabolism, and the metabolism of drugs and xenobiotics were upregulated, whereas detoxifying proteins, mitochondrial precursors, transport proteins, proteasomes, and proteins involved in amino acid metabolism were downregulated. On the other hand, VWR counteracted the protein expression profile of HFD-fed mice by upregulating molecular chaperones, gluconeogenesis-, detoxification-, proteasome-, and energy metabolism-related proteins. This study provided a molecular understanding of the HFD- and exercise-induced protein marker expression and presented the beneficial effects of exercise during pathophysiological conditions.

Biochemical and biophysical characterization of the selenium-binding and reducing site in Arabidopsis thaliana homologue to mammals selenium-binding protein 1

The function of selenium-binding protein 1 (SBP1), present in almost all organisms, has not yet been established. In mammals, SBP1 is known to bind the essential element selenium but the binding site has not been identified. In addition, the SBP family has numerous potential metal-binding sites that may play a role in detoxification pathways in plants. In Arabidopsis thaliana, AtSBP1 over-expression increases tolerance to two toxic compounds for plants, selenium and cadmium, often found as soil pollutants. For a better understanding of AtSBP1 function in detoxification mechanisms, we investigated the chelating properties of the protein toward different ligands with a focus on selenium using biochemical and biophysical techniques. Thermal shift assays together with inductively coupled plasma mass spectrometry revealed that AtSBP1 binds selenium after incubation with selenite (SeO3(2-)) with a ligand to protein molar ratio of 1:1. Isothermal titration calorimetry confirmed the 1:1 stoichiometry and revealed an unexpectedly large value of binding enthalpy suggesting a covalent bond between selenium and AtSBP1. Titration of reduced Cys residues and comparative mass spectrometry on AtSBP1 and the purified selenium-AtSBP1 complex identified Cys(21) and Cys(22) as being responsible for the binding of one selenium. These results were validated by site-directed mutagenesis. Selenium K-edge x-ray absorption near edge spectroscopy performed on the selenium-AtSBP1 complex demonstrated that AtSBP1 reduced SeO3(2-) to form a R-S-Se(II)-S-R-type complex. The capacity of AtSBP1 to bind different metals and selenium is discussed with respect to the potential function of AtSBP1 in detoxification mechanisms and selenium metabolism.

Intergenerational genomic DNA methylation patterns in mouse hybrid strains

Background

DNA methylation is a contributing factor to both rare and common human diseases, and plays a major role in development and gene silencing. While the variation of DNA methylation among individuals has been partially characterized, the degree to which methylation patterns are preserved across generations is still poorly understood. To determine the extent of methylation differences between two generations of mice we examined DNA methylation patterns in the livers of eight parental and F1 mice from C57BL/6J and DBA/2J mouse strains using bisulfite sequencing.

Results

We find a large proportion of reproducible methylation differences between C57BL/6J and DBA/2J chromosomes in CpGs, which are highly heritable between parent and F1 mice. We also find sex differences in methylation levels in 396 genes, and 11% of these are differentially expressed between females and males. Using a recently developed approach to identify allelically methylated regions independently of genotypic differences, we identify 112 novel putative imprinted genes and microRNAs, and validate imprinting at the RNA level in 10 of these genes.

Conclusions

The majority of DNA methylation differences among individuals are associated with genetic differences, and a much smaller proportion of these epigenetic differences are due to sex, imprinting or stochastic intergenerational effects. Epigenetic differences can be a determining factor in heritable traits and should be considered in association studies for molecular and clinical traits, as we observed that methylation differences in the mouse model are highly heritable and can have functional consequences on molecular traits such as gene expression.

Potential Role of Selenoenzymes and Antioxidant Metabolism in relation to Autism Etiology and Pathology

Autism and autism spectrum disorders (ASDs) are behaviorally defined, but the biochemical pathogenesis of the underlying disease process remains uncharacterized. Studies indicate that antioxidant status is diminished in autistic subjects, suggesting its pathology is associated with augmented production of oxidative species and/or compromised antioxidant metabolism. This suggests ASD may result from defects in the metabolism of cellular antioxidants which maintain intracellular redox status by quenching reactive oxygen species (ROS). Selenium-dependent enzymes (selenoenzymes) are important in maintaining intercellular reducing conditions, particularly in the brain. Selenoenzymes are a family of ~25 genetically unique proteins, several of which have roles in preventing and reversing oxidative damage in brain and endocrine tissues. Since the brain's high rate of oxygen consumption is accompanied by high ROS production, selenoenzyme activities are particularly important in this tissue. Because selenoenzymes can be irreversibly inhibited by many electrophiles, exposure to these organic and inorganic agents can diminish selenoenzyme-dependent antioxidant functions. This can impair brain development, particularly via the adverse influence of oxidative stress on epigenetic regulation. Here we review the physiological roles of selenoproteins in relation to potential biochemical mechanisms of ASD etiology and pathology.

The link between selenium binding protein from Sinonovacula constricta and environmental pollutions exposure

Selenium binding proteins (SeBPs) play a crucial role in controlling the oxidation/reduction in many physiological processes. Here we reported the isolation and characterization of a cDNA of SeBP gene from Sinonovacula constricta (denoted as ScSeBP). The full-length cDNA of ScSeBP was of 2345 bp, consisting of a 5'UTR of 246 bp, a 3' UTR of 626 bp, and a complete ORF of 1473 bp encoding a polypeptide with 491 amino acid residues. The predicted molecular mass of deduced amino acid of ScSeBP was 54.85 kDa and the theoretical pI was 6.44. Tissue distribution analysis of the ScSeBP revealed that the mRNA transcripts of ScSeBP were constitutively expressed in all examined tissues with the higher expressions in gill, gonad and the haemocytes. The temporal expression of ScSeBP in gill and haemocytes after B[α]P and heavy metals exposure were recorded by qPCR. B[α]P exposure at 0.5 and 5 mg L(-1) caused significant increase in mRNA expression of ScSeBP in haemocytes, but down-regulated ScSeBP mRNA expression in gill. Concerning heavy metals stresses, the suppressed expression patterns were detected in gill and haemocyte except lower concentration of PbCl2 exposure in haemocytes at 12 h. All our results indicated that ScSeBP was one of key effectors in mediating B[α]P and heavy metals exposure.

Proteomic profiling of differentially expressed proteins from Bax inhibitor-1 knockout and wild type mice

Bax inhibitor-1 (BI-1) is an anti-apoptotic protein located in the endoplasmic reticulum (ER). The role of BI-1 has been studied in different physiopathological models including ischemia, diabetes, liver regeneration and cancer. However, fundamental knowledge about the effects of BI-1 deletion on the proteome is lacking. To further explore this protein, we compared the levels of different proteins in bi-1 (-/-) and bi-1 (+/+) mouse tissues by two-dimensional electrophoresis (2-DE) and mass spectrometry (MS). In several bi-1 (-/-) mice, glucose-regulated protein 75 (GRP75/mortalin/ PBP74/mthsp70), peroxiredoxin6 (Prx6) and fumarylacetoacetate hydrolase (FAH) showed a pI shift that could be attributed to post-translational modifications. Selenium-binding protein 2 (SBP2) and ferritin light chain 1 levels were significantly increased. Phosphatidylethanolamine-binding protein-1 (PEBP-1) was dramatically decreased in bi-1 (-/-) mice, which was confirmed by Western blotting. The phosphorylation of GRP75, Prx6 and FAH were compared between bi-1 (+/+) and bi-1 (-/-) mice using liver tissue lysates. Of these three proteins, only one exhibited modified phosphorylation; Tyr phosphorylation of Prx6 was increased in bi-1 (-/-) mice. Our protein profiling results provide fundamental knowledge about the physiopathological function of BI-1.

Aniline-induced nitrosative stress in rat spleen: proteomic identification of nitrated proteins

Aniline exposure is associated with toxicity to the spleen which is characterized by splenomegaly, hyperplasia, fibrosis, and a variety of sarcomas on chronic exposure in rats. However, mechanisms by which aniline elicits splenotoxic responses are not well understood. Earlier we have shown that aniline exposure leads to increased nitration of proteins in the spleen. However, nitrated proteins remain to be characterized. Therefore, in the current study using proteomic approaches, we focused on characterizing the nitrated proteins in the spleen of aniline-exposed rats. Aniline exposure led to increased tyrosine nitration of proteins, as determined by 2D Western blotting with anti-3-nitrotyrosine specific antibody, compared to the controls. The analyzed nitrated proteins were found in the molecular weight range of 27.7 to 123.6kDa. A total of 37 nitrated proteins were identified in aniline-treated and control spleens. Among them, 25 were found only in aniline-treated rats, 11 were present in both aniline-treated and control rats, while one was found in controls only. The nitrated proteins identified mainly represent skeletal proteins, chaperones, ferric iron transporter, enzymes, nucleic acids binding protein, and signaling and protein synthesis pathways. Furthermore, aniline exposure led to significantly increased iNOS mRNA and protein expression in the spleen, suggesting its role in increased reactive nitrogen species formation and contribution to increased nitrated proteins. The identified nitrated proteins provide a global map to further investigate alterations in their structural and functional properties, which will lead to a better understanding of the role of protein nitration in aniline-mediated splenic toxicity.

Decreased selenium-binding protein 1 in esophageal adenocarcinoma results from posttranscriptional and epigenetic regulation and affects chemosensitivity

PURPOSE

The chemopreventive effects of selenium have been extensively examined, but its role in cancer development or as a chemotherapeutic agent has only recently been explored. Because selenium-binding protein 1 (SELENBP1, SBP1, hSP56) has been shown to bind selenium covalently and selenium deficiency has been associated with esophageal adenocarcinoma (EAC), we examined its role in EAC development and its potential effect on chemosensitivity in the presence of selenium.

EXPERIMENTAL DESIGN

SELENBP1 expression level and copy number variation were determined by oligonucleotide microarrays, real-time reverse transcription-PCR, tissue microarrays, immunoblotting, and single-nucleotide polymorphism arrays. Bisulfite sequencing and sequence analysis of reverse transcription-PCR-amplified products explored epigenetic and posttranscriptional regulation of SELENBP1 expression, respectively. WST-1 cell proliferation assays, senescence-associated beta-galactosidase staining, immunoblotting, and flow cytometry were done to evaluate the biological significance of SELENBP1 overexpression in selenium-supplemented EAC cells.

RESULTS

SELENBP1 expression decreased significantly in Barrett's esophagus to adenocarcinoma progression. Both epigenetic and posttranscriptional mechanisms seemed to modulate SELENBP1 expression. Stable overexpression of SELENBP1 in methylseleninic acid-supplemented Flo-1 cells resulted in enhanced apoptosis, increased cellular senescence, and enhanced cisplatin cytotoxicity. Although inorganic sodium selenite similarly enhanced cisplatin cytotoxicity, these two forms of selenium elicited different cellular responses.

CONCLUSIONS

SELENBP1 expression may be an important predictor of response to chemoprevention or chemosensitization with certain forms of selenium in esophageal tissues. AACR.

Integrated hepatic transcriptome and proteome analysis of mice with high-fat diet-induced nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease in the US and refers to a wide spectrum of liver damage, including simple steatosis, steatohepatitis, fibrosis and cirrhosis. The goal of the present study was to achieve a more detailed understanding of the molecular changes in response to high fat-induced liver steatosis through the identification of a differentially expressed liver transcriptome and proteome. Male C57/BL6 mice fed a high-fat lard diet for 8 weeks developed visceral obesity and hepatic steatosis characterized by significantly increased liver and plasma free fatty acid and triglyceride levels and plasma alanine aminotransferase activities. Transcriptome analysis demonstrated that, compared to the control diet (CD), high-fat diet changed the expression of 309 genes (132 up- and 177 down-regulated; by a twofold change and more, P<.05). Multiple genes encoding proteins involved in lipogenesis were down-regulated, whereas genes involved in fatty acid oxidation were up-regulated. Proteomic analysis revealed 12 proteins which were differentially expressed. Of these, glutathione S-transferases mu1 and pi1 and selenium-binding protein 2 were decreased at both the gene and protein levels. This is the first study to perform a parallel transcriptomic and proteomic analysis of diet-induced hepatic steatosis. Several key pathways involving xenobiotic and lipid metabolism, the inflammatory response and cell-cycle control were identified. These pathways provide targets for future mechanistic and therapeutic studies as related to the development and prevention of NAFLD.

Arabidopsis putative selenium-binding protein1 expression is tightly linked to cellular sulfur demand and can reduce sensitivity to stresses requiring glutathione for tolerance

Selenium-Binding Protein1 (SBP1) gene expression was studied in Arabidopsis (Arabidopsis thaliana) seedlings challenged with several stresses, including cadmium (Cd), selenium {selenate [Se(VI)] and selenite [Se(IV)]}, copper (Cu), zinc (Zn), and hydrogen peroxide (H(2)O(2)) using transgenic lines expressing the luciferase (LUC) reporter gene under the control of the SBP1 promoter. In roots and shoots of SBP1LUC lines, LUC activity increased in response to Cd, Se(VI), Cu, and H(2)O(2) but not in response to Se(IV) or Zn. The pattern of expression of SBP1 was similar to that of PRH43, which encodes the 5'-Adenylylphosphosulfate Reductase2, a marker for the induction of the sulfur assimilation pathway, suggesting that an enhanced sulfur demand triggers SBP1 up-regulation. Correlated to these results, SBP1 promoter showed enhanced activity in response to sulfur starvation. The sulfur starvation induction of SBP1 was abolished by feeding the plants with glutathione (GSH) and was enhanced when seedlings were treated simultaneously with buthionine sulfoxide, which inhibits GSH synthesis, indicating that GSH level participates in the regulation of SBP1 expression. Changes in total GSH level were observed in seedlings challenged with Cd, Se(VI), and H(2)O(2). Accordingly, cad2-1 seedlings, affected in GSH synthesis, were more sensitive than wild-type plants to these three stresses. Moreover, wild-type and cad2-1 seedlings overexpressing SBP1 showed a significant enhanced tolerance to Se(VI) and H(2)O(2) in addition to the previously described resistance to Cd, highlighting that SBP1 expression decreases sensitivity to stress requiring GSH for tolerance. These results are discussed with regard to the potential regulation and function of SBP1 in plants.

A systematic proteomic study of irradiated DNA repair deficient Nbn-mice

Background

The NBN gene codes for the protein nibrin, which is involved in the detection and repair of DNA double strand breaks (DSBs). The NBN gene is essential in mammals.

Methodology/Principal Findings

We have used a conditional null mutant mouse model in a proteomics approach to identify proteins with modified expression levels after 4 Gy ionizing irradiation in the absence of nibrin in vivo. Altogether, amongst ∼8,000 resolved proteins, 209 were differentially expressed in homozygous null mutant mice in comparison to control animals. One group of proteins significantly altered in null mutant mice were those involved in oxidative stress and cellular redox homeostasis (p<0.0001). In substantiation of this finding, analysis of Nbn null mutant fibroblasts indicated an increased production of reactive oxygen species following induction of DSBs.

Conclusions/Significance

In humans, biallelic hypomorphic mutations in NBN lead to Nijmegen breakage syndrome (NBS), an autosomal recessive genetic disease characterised by extreme radiosensitivity coupled with growth retardation, immunoinsufficiency and a very high risk of malignancy. This particularly high cancer risk in NBS may be attributable to the compound effect of a DSB repair defect and oxidative stress.

The impact of surfactant protein-A on ozone-induced changes in the mouse bronchoalveolar lavage proteome

Background

Ozone is a major component of air pollution. Exposure to this powerful oxidizing agent can cause or exacerbate many lung conditions, especially those involving innate immunity. Surfactant protein-A (SP-A) plays many roles in innate immunity by participating directly in host defense as it exerts opsonin function, or indirectly via its ability to regulate alveolar macrophages and other innate immune cells. The mechanism(s) responsible for ozone-induced pathophysiology, while likely related to oxidative stress, are not well understood.

Methods

We employed 2-dimensional difference gel electrophoresis (2D-DIGE), a discovery proteomics approach, coupled with MALDI-ToF/ToF to compare the bronchoalveolar lavage (BAL) proteomes in wild type (WT) and SP-A knockout (KO) mice and to assess the impact of ozone or filtered air on the expression of BAL proteins. Using the PANTHER database and the published literature most identified proteins were placed into three functional groups.

Results

We identified 66 proteins and focused our analysis on these proteins. Many of them fell into three categories: defense and immunity; redox regulation; and protein metabolism, modification and chaperones. In response to the oxidative stress of acute ozone exposure (2 ppm; 3 hours) there were many significant changes in levels of expression of proteins in these groups. Most of the proteins in the redox group were decreased, the proteins involved in protein metabolism increased, and roughly equal numbers of increases and decreases were seen in the defense and immunity group. Responses between WT and KO mice were similar in many respects. However, the percent change was consistently greater in the KO mice and there were more changes that achieved statistical significance in the KO mice, with levels of expression in filtered air-exposed KO mice being closer to ozone-exposed WT mice than to filtered air-exposed WT mice.

Conclusion

We postulate that SP-A plays a role in reactive oxidant scavenging in WT mice and that its absence in the KO mice in the presence or absence of ozone exposure results in more pronounced, and presumably chronic, oxidative stress.

Proteomic analysis of the rat ovary following chronic low-dose exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitously distributed endocrine-disrupting chemical and reproductive toxicant. In order to elucidate low-dose TCDD-mediated effects on reproductive or endocrine functions, female Sprague-Dawley rats were orally administered various concentrations (20, 50, or 125 ng/kg once weekly) TCDD for 29 wk. A proteomic analysis of the ovaries by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry showed distinct changes in the levels of several proteins that are relevant markers of TCDD toxicity. Serum estradiol (E2) levels of TCDD-treated animals were markedly lower than control. There were no significant differences in bone mineral density (BMD) of femurs. The body weight of the 125-ng/kg TCDD group was significantly decreased relative to control and there was also a significant reduction in absolute and relative ovarian weights. Expressions of selenium binding protein 2, glutathione S-transferase mu type 3, Lrpap1 protein, NADPH, and peptidylprolyl isomerase D were upregulated, while prohibitin and N-ethylmaleimide-sensitive factor expression levels were downregulated. Data provide further insight into the mechanisms by which TCDD disrupts ovarian function by indicating which differential protein expressions following low-dose TCDD exposure.

Gender-specific proteomic responses in zebrafish liver following exposure to a selected mixture of brominated flame retardants

Proteomic effect screening in zebrafish liver was performed to generate hypotheses following exposure (21 days) to a structurally diverse mixture of brominated flame retardants (BFRs). Fish were exposed to two doses (10 and 100 nmol/g feed). Two-dimensional gel-electrophoresis, image analysis and MALDI-TOF mass-spectrometry revealed 13 and 19 significant responses in males and females, respectively. Effects on proteins related to cellular maintenance and stress were observed in both genders. Regulated proteins were gender-specific, but functionally indicated common protective responses (peroxiredoxin 6 and Zgc:92891 in males and transketolase in females) suggesting oxidative stress. Betaine homocysteine methyltransferase (BHMT) was induced in both genders. In addition a female-specific downregulation of ironhomeostatic proteins (iron-regulatory protein 1 and transferrin) were observed. Our proteomic approach revealed novel responses that suggest important gender-specific sensitivity to BFRs that should be considered when interpreting adverse effects of BFRs.

The Arabidopsis putative selenium-binding protein family: expression study and characterization of SBP1 as a potential new player in cadmium detoxification processes

In Arabidopsis (Arabidopsis thaliana), the putative selenium-binding protein (SBP) gene family is composed of three members (SBP1-SBP3). Reverse transcription-polymerase chain reaction analyses showed that SBP1 expression was ubiquitous. SBP2 was expressed at a lower level in flowers and roots, whereas SBP3 transcripts were only detected in young seedling tissues. In cadmium (Cd)-treated seedlings, SBP1 level of expression was rapidly increased in roots. In shoots, SBP1 transcripts accumulated later and for higher Cd doses. SBP2 and SBP3 expression showed delayed or no responsiveness to Cd. In addition, luciferase (LUC) activity recorded on Arabidopsis lines expressing the LUC gene under the control of the SBP1 promoter further showed dynamic regulation of SBP1 expression during development and in response to Cd stress. Western-blot analysis using polyclonal antibodies raised against SBP1 showed that SBP1 protein accumulated in Cd-exposed tissues in correlation with SBP1 transcript amount. The sbp1 null mutant displayed no visible phenotype under normal and stress conditions that was explained by the up-regulation of SBP2 expression. SBP1 overexpression enhanced Cd accumulation in roots and reduced sensitivity to Cd in wild type and, more significantly, in Cd-hypersensitive cad mutants that lack phytochelatins. Similarly, in Saccharomyces cerevisiae, SBP1 expression led to increased Cd tolerance of the Cd-hypersensitive ycf1 mutant. In vitro experiments showed that SBP1 has the ability to bind Cd. These data highlight the importance of maintaining the adequate SBP protein level under healthy and stress conditions and suggest that, during Cd stress, SBP1 accumulation efficiently helps to detoxify Cd potentially through direct binding.

Changes of the hepatic proteome in murine models for toxically induced fibrogenesis and sclerosing cholangitis

We investigated the changes in the hepatic proteome in murine models for toxic-induced fibrogenesis and sclerosing cholangitis. A comprehensive comparison of protein changes observed is made and the mechanistical basis of the expression changes is discussed. Hepatic fibrosis was induced by repetitive intraperitoneal CCl4 treatment of BALB/c mice or developed spontaneously in BALB/c-ATP-binding cassette, subfamily B, member 4 (Abcb4) knock out mice. Fibrosis was verified by a morphometric score and assessment of hydroxyproline content of liver tissue, respectively. The innovative difference in-gel electrophoresis (DIGE) technique was used to analyse protein expression levels of the mouse proteome. Results were confirmed by Western blotting and real-time RT-PCR. In CCl4-induced fibrosis 20 out of 40 and in BALB/c-Abcb4(-/-) mice 8 out of 28 differentially expressed proteins were identified utilizing DIGE. Only two proteins, selenium-binding protein (Sbp2) and carbonic anhydrase 3, have been unidirectionally expressed (i.e. down-regulated) in both models. Relevant differences in the pathogenesis of toxically induced liver fibrosis and sclerosing cholangitis exist. The only novel protein with regard to liver fibrosis depicting a unidirectional expression pattern in both animal models was Sbp2. An explicit protein function could not be clarified yet.

Stress resistance and aging: influence of genes and nutrition

Previous studies have shown that dermal fibroblast cell lines derived from young adult mice of the long-lived Snell dwarf (dw/dw), Ames dwarf (df/df) and growth hormone receptor knockout (GHR-KO) mouse stocks are resistant, in vitro, to the cytotoxic effects of hydrogen peroxide, cadmium, ultraviolet light, paraquat, and heat. Here we show that, in contrast, fibroblasts from mice on low-calorie (CR) or low methionine (Meth-R) diets are not stress resistant in culture, despite the longevity induced by both dietary regimes. A second approach, involving induction of liver cell death in live animals using acetaminophen (APAP), documented hepatotoxin resistance in the CR and Meth-R mice, but dw/dw and GHR-KO mutant mice were not resistant to this agent, and were in fact more susceptible than littermate controls to the toxic effects of APAP. These data thus suggest that while resistance to stress is a common characteristic of experimental life span extension in mice, the cell types showing resistance may differ among the various models of delayed or decelerated aging.