Pneumocytes are distinguished by highly elevated expression of the ER stress biomarker GRP78, a co-receptor for SARS-CoV-2, in COVID-19 autopsies

Vaccinations are widely credited with reducing death rates from COVID-19, but the underlying host-viral mechanisms/interactions for morbidity and mortality of SARS-CoV-2 infection remain poorly understood. Acute respiratory distress syndrome (ARDS) describes the severe lung injury, which is pathologically associated with alveolar damage, inflammation, non-cardiogenic edema, and hyaline membrane formation. Because proteostatic pathways play central roles in cellular protection, immune modulation, protein degradation, and tissue repair, we examined the pathological features for the unfolded protein response (UPR) using the surrogate biomarker glucose-regulated protein 78 (GRP78) and co-receptor for SARS-CoV-2. At autopsy, immunostaining of COVID-19 lungs showed highly elevated expression of GRP78 in both pneumocytes and macrophages compared with that of non-COVID control lungs. GRP78 expression was detected in both SARS-CoV-2-infected and un-infected pneumocytes as determined by multiplexed immunostaining for nucleocapsid protein. In macrophages, immunohistochemical staining for GRP78 from deceased COVID-19 patients was increased but overlapped with GRP78 expression taken from surgical resections of non-COVID-19 controls. In contrast, the robust in situ GRP78 immunostaining of pneumocytes from COVID-19 autopsies exhibited no overlap and was independent of age, race/ethnicity, and gender compared with that from non-COVID-19 controls. Our findings bring new insights for stress-response pathways involving the proteostatic network implicated for host resilience and suggest that targeting of GRP78 expression with existing therapeutics might afford an alternative therapeutic strategy to modulate host-viral interactions during SARS-CoV-2 infections.

Vaspin, a novel adipokine in woman granulosa cells physiology and PCOS pathogenesis?

Vaspin is a novel adipokine mainly expressed in visceral adipose tissue and closely related to obesity and insulin-resistance. Currently, data about its ovarian expression are limited to animal models and its role in human reproduction is largely unexplored. Our study's aims were then to characterise vaspin expression in the human ovary and to study in vitro its effects on granulosa cells physiology. Secondly, we assessed vaspin and its receptor GRP78 variations in granulosa cells and follicular fluid of a cohort of 112 infertile women undergoing an in vitro fertilisation procedure and allocated to three groups, each including normal-weight and obese subjects: 34 PCOS patients, 33 women with isolated polycystic ovary morphology (ECHO group) and 45 controls. Vaspin and GRP78 expression in the ovary was assessed by immunohistochemistry, RT-qPCR and Western blot. Granulosa cells and follicular fluid were analysed by RT-qPCR and ELISA, respectively. In vitro, granulosa cells metabolism was studied after stimulation with recombinant human vaspin, with and without a siRNA directed against GRP78. Vaspin was highly expressed in the human ovary and concentration-dependently enhanced granulosa cells steroidogenesis, proliferation and viability through GRP78 (P < 0.0001). Vaspin levels in both granulosa cells and follicular fluid were significantly higher in obese women (P < 0.0001) and in the normal-weight ECHO group (P < 0.001), which also had the highest expression rates of GRP78 (P < 0.05). Although further investigation is needed, vaspin appears as a novel modulator of human granulosa cells physiology and possibly plays a role in PCOS pathogenesis, notably protecting from insulin-resistance induced complications.

Cluster analyses of the TCGA and a TMA dataset using the coexpression of HSP27 and CRYAB improves alignment with clinical-pathological parameters of breast cancer and suggests different epichaperome influences for each sHSP

Our cluster analysis of the Cancer Genome Atlas for co-expression of HSP27 and CRYAB in breast cancer patients identified three patient groups based on their expression level combination (high HSP27 + low CRYAB; low HSP27 + high CRYAB; similar HSP27 + CRYAB). Our analyses also suggest that there is a statistically significant inverse relationship between HSP27 and CRYAB and known clinicopathological markers in breast cancer. Screening an unbiased 248 breast cancer patient tissue microarray (TMA) for the protein expression of HSP27 and phosphorylated HSP27 (HSP27-82pS) with CRYAB also identified three patient groups based on HSP27 and CRYAB expression levels. TMA24 also had recorded clinical-pathological parameters, such as ER and PR receptor status, patient survival, and TP53 mutation status. High HSP27 protein levels were significant with ER and PR expression. HSP27-82pS associated with the best patient survival (Log Rank test). High CRYAB expression in combination with wild-type TP53 was significant for patient survival, but a different patient outcome was observed when mutant TP53 was combined with high CRYAB expression. Our data suggest that HSP27 and CRYAB have different epichaperome influences in breast cancer, but more importantly evidence the value of a cluster analysis that considers their coexpression. Our approach can deliver convergence for archival datasets as well as those from recent treatment and patient cohorts and can align HSP27 and CRYAB expression to important clinical-pathological features of breast cancer.

Prognosis and predictive value of heat-shock proteins expression in oral cancer: A PRISMA-compliant meta-analysis

BACKGROUND

Heat-shock proteins (HSP) is a key chaperone protein which maintains intracellular proteostasis and is expressed on the surface of solid and hematological malignancies. Several studies have reported paradoxical evidence of the association between HSP expression and prognosis of oral cancer. To address the discrepancy, we carried out the meta-analysis to assess the role of HSP such as: HSP70, HSP90, HSP27, HSP60, and HSP105 in susceptibility, progression, and prognosis of oral cancer.

MATERIALS AND METHODS

We retrieved the PubMed, Embase, Web of science, China National Knowledge Infrastructure (CNKI), and Wanfang databases to acquire the eligible studies which were associated with HSP70, HSP90, HSP27, HSP60, and HSP105 protein expression and oral cancer. We applied hazard ratio (HR) and its 95% confidence interval (95% CI) to assess the value of HSP protein expression in overall survival of oral cancer; odds ratio (OR) and its 95% CI were used to evaluate the association of risk and clinical features of oral cancer. Funnel plot, Begg test, and Egger line regression test were utilized to observe publication bias among studies. All statistical analysis was performed with Stata 14.0 software (Stata Corporation, College Station, TX).

RESULTS

A total of 26 studies were included in the present meta-analysis. On based of the results, HSP70 and HSP27 had no significant association with progression of oral cancer. However, the pooled HR and 95% CI revealed a significant well effects of HSP70 and HSP27 expression on survival of oral cancer. Moreover, the susceptibility of oral cancer was significantly associated with HSP70 and HSP60 overexpression.

CONCLUSION

HSP70 and HSP27 protein overexpression might be valuable biomarkers for the prognosis of oral cancer. And HSP70 and HSP60 might have potential predictive effects on the risk of oral cancer.

Molecular characterization and expression patterns of heat shock proteins in Spodoptera littoralis, heat shock or immune response?

The Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.), is a major agricultural lepidopterous pest causing extensive damage in a variety of crops including vegetable, cotton, fodder, and fiber crops. Heat shock protein (HSP) family members play important roles in protecting insects against environmental stressors. In this study, we characterized three putative heat shock proteins (SpliHsp70, SpliHsp90, and SpliHSF) from S. littoralis and analyzed their expression levels in response to heat, cold, ultraviolet irradiation, Bacillus thuringiensis, and Spodoptera littoralis nucleopolyhedrovirus treatments. Significant upregulation of SpliHsp70 was observed in female pupae, while the highest expression levels of SpliHsp90 and SpliHSF were found in female adults. Heat shock triggered increases in SpliHsp levels compared to cold treatment. SpliHsp90 exhibited the highest expression levels during the first 30 min of UV treatment. Both bacterial and viral pathogenic agents effected the regulation of Hsps in S. littoralis. These findings suggest that SpliHsp genes might play significant roles in the response to biotic and abiotic stress, as well as in the regulation of developmental stages.

Development of molecular and histological methods to evaluate stress oxidative biomarkers in sea bass (Dicentrarchus labrax)

In aquaculture, fish species may experience stressful episodes caused by poor farming conditions. The exponential increase of global aquaculture has raised the number of research studies aimed at demonstrating the sensitivity of aquatic animals in confined environments. The development of a real-time PCR and immunohistochemistry methods were investigated to evaluate the presence, localization, and quantity of biomarkers of oxidative stress in European sea bass (Dicentrarchus labrax). In particular, stress tests such as manipulation and temperature changes were conducted through molecular methods to identify the expression level of heat shock protein 70 (HSP70) in stressed animals compared with a control group. The immunohistochemical technique was also applied to locate and study the trends-levels of nitrotyrosine (NT), heat shock protein 70 (HSP70), malondialdehyde (MDA), and 4-hydroxy-2-nonenal (HNE) in different tissues from stressed animals and control group. The presence of the rodlet cell (RCs) was evaluated by histology in both a control and stressed group. Our results show that the real-time PCR method developed is specific for the evaluated target gene and that manipulation and temperature increase are strong stressors for animals. Relative quantification data revealed a gene expression increase of HSP70 in the stressed group of animals compared to the control group. The antibodies used for the immunohistochemical staining were efficient, and it was possible to appreciate the increase of immunoprecipitates in European sea bass either manipulated or stressed by temperature increase. The present study can be a starting point to allow the quantification of HSP70 and the identification of other stress biomarkers in D. labrax.

Heat shock proteins (HSP 90, 70, 60, and 27) in Galleria mellonella (Lepidoptera) hemolymph are affected by infection with Conidiobolus coronatus (Entomophthorales)

Invertebrates are becoming more popular models for research on the immune system. The innate immunity possessed by insects shows both structural and functional similarity to the resistance displayed by mammals, and many processes occurring in insect hemocytes are similar to those that occur in mammals. The humoral immune response in insects acts by melanization, clotting and the production of reactive oxygen species and antimicrobial peptides, while the cellular immunity system is based on nodulation, encapsulation and phagocytosis. An increasingly popular insect model in biological research is Galleria mellonella, whose larvae are sensitive to infection by the entomopathogenic fungus Conidiobolus coronatus, which can also be dangerous to humans. One group of factors that modulate the response of the immune system during infection in mammals are heat shock proteins (HSPs). The aim of this study was to investigate whether infection by C. coronatus in G. mellonella hemolymph is accompanied by an increase of HSP90, HSP70, HSP60 and HSP27. Larvae (five-day-old last instar) were exposed for 24 hours to fully-grown and sporulating fungus. Hemolymph was collected either immediately after termination of exposure (F24) or 24 hours later (F48). The concentration of the HSPs in hemolymph was determined using ELISA. Immunolocalization in hemocytes was performed using fluorescence microscopy and flow cytometry. HSP90, HSP70, HSP60 and HSP27 were found to be present in the G. mellonella hemocytes. HSP60 and HSP90 predominated in healthy insects, with HSP70 and HSP27 being found in trace amounts; HSP60 and HSP27 were elevated in F24 and F48, and HSP90 was elevated in F48. The fungal infection had no effect on HSP70 levels. These findings shed light on the mechanisms underlying the interaction between the innate insect immune response and entomopathogen infection. The results of this innovative study may have a considerable impact on research concerning innate immunology and insect physiology.

Proteomic changes of the porcine skeletal muscle in response to chronic heat stress

BACKGROUND

Heat stress (HS) has an adverse effect on meat quality; however, the underlying molecular mechanisms altering meat quality due to muscle responses to stress remain unclear. Sixteen castrated male crossbreeds between Landrace × Yorkshire sows and Duroc boars (79.00 ± 1.50 kg body weight) were exposed to either thermal neutral (22 °C, n = 8) or HS (30 °C, n = 8) conditions for 3 weeks. Subsequently, the longissimus dorsi (LD) muscle of all pigs was assayed for meat quality parameters and proteome analysis.

RESULTS

HS decreased post mortem (24 h) pH and intramuscular fat, changed ultimate L*, a* and b* values and increased drip loss and shear force. Proteome analysis of the LD was conducted by two-dimensional gel electrophoresis and mass spectrometry. A total of 23 differentially expressed proteins were identified, of which three were verified by western blotting analysis. The identified proteins were involved in six types of biological process: carbohydrate metabolism, myofibrillar and cytoskeleton structure, stress response, antioxidant and detoxification, calcium binding and cellular apoptosis. Interestingly, HS induced higher levels of heat shock protein, antioxidants and calcium binding proteins, which are involved in the mechanisms of defense and homeostasis.

CONCLUSION

The results indicate that HS-induced changes in the expression of myofibrillar proteins, glucose and energy metabolism-related proteins, heat shock protein and antioxidant enzymes might, at least partly, contribute to increase in meat tenderness. These findings will provide the foundation for developing future mitigating solutions and preventative therapies to reduce the detrimental effects of chronic HS on muscle function, metabolism and meat quality. © 2017 Society of Chemical Industry.

Chronic Intermittent Hypobaric Hypoxia Improves Cardiac Function through Inhibition of Endoplasmic Reticulum Stress

We investigated the role of endoplasmic reticulum stress (ERS) in chronic intermittent hypobaric hypoxia (CIHH)-induced cardiac protection. Adult male Sprague-Dawley rats were exposed to CIHH treatment simulating 5000 m altitude for 28 days, 6 hours per day. The heart was isolated and perfused with Langendorff apparatus and subjected to 30-min ischemia followed by 60-min reperfusion. Cardiac function, infarct size, and lactate dehydrogenase (LDH) activity were assessed. Expression of ERS molecular chaperones (GRP78, CHOP and caspase-12) was assayed by western blot analysis. CIHH treatment improved the recovery of left ventricular function and decreased cardiac infarct size and activity of LDH after I/R compared to control rats. Furthermore, CIHH treatment inhibited over-expression of ERS-related factors including GRP78, CHOP and caspase-12. CIHH-induced cardioprotection and inhibition of ERS were eliminated by application of dithiothreitol, an ERS inducer, and chelerythrine, a protein kinase C (PKC) inhibitor. In conclusion CIHH treatment exerts cardiac protection against I/R injury through inhibition of ERS via PKC signaling pathway.

Fine-tuning of actin dynamics by the HSPB8-BAG3 chaperone complex facilitates cytokinesis and contributes to its impact on cell division

The small heat shock protein HSPB8 and its co-chaperone BAG3 are proposed to regulate cytoskeletal proteostasis in response to mechanical signaling in muscle cells. Here, we show that in dividing cells, the HSPB8-BAG3 complex is instrumental to the accurate disassembly of the actin-based contractile ring during cytokinesis, a process required to allow abscission of daughter cells. Silencing of HSPB8 markedly decreased the mitotic levels of BAG3 in HeLa cells, supporting its crucial role in BAG3 mitotic functions. Cells depleted of HSPB8 were delayed in cytokinesis, remained connected via a disorganized intercellular bridge, and exhibited increased incidence of nuclear abnormalities that result from failed cytokinesis (i.e., bi- and multi-nucleation). Such phenotypes were associated with abnormal accumulation of F-actin at the intercellular bridge of daughter cells at telophase. Remarkably, the actin sequestering drug latrunculin A, like the inhibitor of branched actin polymerization CK666, normalized F-actin during cytokinesis and restored proper cell division in HSPB8-depleted cells, implicating deregulated actin dynamics as a cause of abscission failure. Moreover, this HSPB8-dependent phenotype could be corrected by rapamycin, an autophagy-promoting drug, whereas it was mimicked by drugs impairing lysosomal function. Together, the results further support a role for the HSPB8-BAG3 chaperone complex in quality control of actin-based structure dynamics that are put under high tension, notably during cell cytokinesis. They expand a so-far under-appreciated connection between selective autophagy and cellular morphodynamics that guide cell division.

Silver nanoparticles and dissolved silver activate contrasting immune responses and stress-induced heat shock protein expression in sea urchin

Using immune cells of sea urchin Strongylocentrotus droebachiensis in early development as a model, the cellular protective mechanisms against ionic and poly(allylamine)-coated silver nanoparticle (AgNPs; 14 ± 6 nm) treatments at 100 μg L^-1 were investigated. Oxidative stress, heat shock protein expression, and pigment production by spherulocytes were determined as well as AgNP translocation pathways and their multiple effects on circulating coelomocytes. Sea urchins showed an increasing resilience to Ag over time because ionic Ag is accumulated in a steady way, although nanoAg levels dropped between 48 h and 96 h. A clotting reaction emerged on tissues injured by dissolved Ag (present as chloro-complexes in seawater) between 12 h and 48 h. Silver contamination and nutritional state influenced the production of reactive oxygen species. After passing through coelomic sinuses and gut, AgNPs were found in coelomocytes. Inside blood vessels, apoptosis-like processes appeared in coelomocytes highly contaminated by poly(allylamine)-coated AgNPs. Increasing levels of Ag accumulated by urchins once exposed to AgNPs pointed to a Trojan-horse mechanism operating over 12-d exposure. However, under short-term treatments, physical interactions of poly(allylamine)-coated AgNPs with cell structures might be, at some point, predominant and responsible for the highest levels of stress-related proteins detected. The present study is the first report detailing nano-translocation in a marine organism and multiple mechanisms by which sea urchin cells can deal with toxic AgNPs. Environ Toxicol Chem 2017;36:1872-1886. © 2016 SETAC.

Gene Expression Profiling of Mouse Condylar Cartilage during Mastication by Means of Laser Microdissection and cDNA Array

Little is known about the mechanisms of mandibular condylar growth. In this study, gene expression in the mandibular condylar cartilage of young post-natal mice was monitored by means of a cDNA microarray, real-time PCR, and laser microdissection before and after the initiation of mastication (newborn, 7 days, 21 days, initiation of mastication, and 35 days). Insulin-like growth factor-1 (IGF-I), transforming-growth-factor-beta-2 (TGFbeta2), and aggrecan mRNAs were clearly expressed at 21 days, while the expression of osteopontin mRNAs was most clear at 35 days. Parathyroid-hormone-related protein (PTHrP), Indian-hedgehog (Ihh), and insulin-like growth factor-2 (IGF-2) mRNAs were clearly expressed during lactation (newborn and 7 days). Heat-shock-protein 84 (HSP-84) and heat-shock-protein 86 (HSP-86) were clearly expressed at 35 days. These results revealed that gene expression changed during mandibular condylar cartilage growth, and that, interestingly, these changes coincided with the initiation of mastication.

A Novel Class of Hsp90 C-Terminal Modulators Have Pre-Clinical Efficacy in Prostate Tumor Cells Without Induction of a Heat Shock Response

BACKGROUND

While there is compelling rationale to use heat shock protein 90 (Hsp90) inhibitors for treatment of advanced prostate cancer, agents that target the N-terminal ATP-binding site of Hsp90 have shown little clinical benefit. These N-terminal binding agents induce a heat shock response that activates compensatory heat shock proteins, which is believed to contribute in part to the agents' lack of efficacy. Here, we describe the functional characterization of two novel agents, SM253 and SM258, that bind the N-middle linker region of Hsp90, resulting in reduced client protein activation and preventing C-terminal co-chaperones and client proteins from binding to Hsp90.

METHODS

Inhibition of Hsp90 activity in prostate cancer cells by SM253 and SM 258 was assessed by pull-down assays. Cell viability, proliferation and apoptosis were assayed in prostate cancer cell lines (LNCaP, 22Rv1, PC-3) cultured with N-terminal Hsp90 inhibitors (AUY922, 17-AAG), SM253 or SM258. Expression of HSR heat shock proteins, Hsp90 client proteins and co-chaperones was assessed by immunoblotting. Efficacy of the SM compounds was evaluated in human primary prostate tumors cultured ex vivo by immunohistochemical detection of Hsp70 and Ki67.

RESULTS

SM253 and SM258 exhibit antiproliferative and pro-apoptotic activity in multiple prostate cancer cell lines (LNCaP, 22Rv1, and PC-3) at low micromolar concentrations. Unlike the N-terminal inhibitors AUY922 and 17-AAG, these SM agents do not induce expression of Hsp27, Hsp40, or Hsp70, proteins that are characteristic of the heat shock response, in any of the prostate cell lines analyzed. Notably, SM258 significantly reduced proliferation within 2 days in human primary prostate tumors cultured ex vivo, without the significant induction of Hsp70 that was caused by AUY922 in the tissues.

CONCLUSIONS

Our findings provide the first evidence of efficacy of this class of C-terminal modulators of Hsp90 in human prostate tumors, and indicate that further evaluation of these promising new agents is warranted. Prostate 76:1546-1559, 2016. © 2016 Wiley Periodicals, Inc.

Accumulation and detoxification dynamics of microcystin-LR and antioxidant responses in male red swamp crayfish Procambarus clarkii

MC-LR is one of major microcystin isoforms with potent hepatotoxicity. In the present study, we aim to: 1) explore the dynamics of MC-LR accumulation and elimination in different tissues of male red swamp crayfish Procambarus clarkii; 2) reveal the mechanisms underlying hepatic antioxidation and detoxification. In the semi-static toxicity tests under the water temperature of 25±2°C, P. clarkii were exposed to 0.1, 1, 10 and 100μg/L MC-LR for 7days for accumulation and subsequently relocated to freshwater for another 7days to depurate MC-LR. MC-LR was measured in the hepatopancreas, intestine, abdominal muscle and gill by HPLC. The enzyme activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST), content of glutathione (GSH), and transcripts of Mn-sod, cat, gpx1, Mu-gst, heat shock protein90 (hsp90), hsp70 and hsp60 in hepatopancreas were detected. The results showed that P. clarkii accumulated more MC-LR in intestine, and less in abdominal muscle and gill during accumulation period and eliminated the toxin more quickly in gill and abdominal muscle, and comparatively slowly in intestine during depuration period. The fast increase of SOD and CAT activities at early stage, subsequent decrease at later stage of accumulation period and then fast increase during depuration period were partially consistent with the transcriptional changes of their respective genes. GPx was activated by longer MC-LR exposure and gpx1 mRNA expression showed uncoordinated regulation pattern compared with its enzyme. Hsp genes were up-regulated when P. clarkii was exposed to MC-LR.

Exosomes secreted under hypoxia enhance invasiveness and stemness of prostate cancer cells by targeting adherens junction molecules

Hypoxic conditions in prostate cancer (PCA) are associated with poor prognosis; however, precise mechanism/s through which hypoxia promotes malignant phenotype remains unclear. Here, we analyzed the role of exosomes from hypoxic PCA cells in enhancing the invasiveness and stemness of naïve PCA cells, as well as in promoting cancer-associated fibroblast (CAF) phenotype in prostate stromal cells (PrSC). Human PCA LNCaP and PC3 cells were exposed to hypoxic (1% O2 ) or normoxic (21% O2 ) conditions, and exosomes secreted under hypoxic (Exo(Hypoxic) ) and normoxic (Exo(Normoxic) ) conditions were isolated from conditioned media. Nanoparticle tracking analysis revealed that Exo(Hypoxic) have smaller average size as compared to Exo(Normoxic) . Immunoblotting results showed a higher level of tetraspanins (CD63 and CD81), heat shock proteins (HSP90 and HSP70), and Annexin II in Exo(Hypoxic) compared to Exo(Normoxic) . Co-culturing with Exo(Hypoxic) increased the invasiveness and motility of naïve LNCaP and PC3 cells, respectively. Exo(Hypoxic) also promoted prostasphere formation by both LNCaP and PC3 cells, and enhanced α-SMA (a CAF biomarker) expression in PrSC. Compared to Exo(Normoxic) , Exo(Hypoxic) showed higher metalloproteinases activity and increased level of diverse signaling molecules (TGF-β2, TNF1α, IL6, TSG101, Akt, ILK1, and β-catenin). Furthermore, proteome analysis revealed a higher number of proteins in Exo(Hypoxic) (160 proteins) compared to Exo(Normoxic) (62 proteins), primarily associated with the remodeling of epithelial adherens junction pathway. Importantly, Exo(Hypoxic) targeted the expression of adherens junction proteins in naïve PC3 cells. These findings suggest that Exo(Hypoxic) are loaded with unique proteins that could enhance invasiveness, stemness, and induce microenvironment changes; thereby, promoting PCA aggressiveness.

Melatonin induces class A1 heat-shock factors (HSFA1s) and their possible involvement of thermotolerance in Arabidopsis

Melatonin (N-acetyl-5-methoxytryptamine) serves as an important signal molecule during plant developmental processes and multiple abiotic stress responses. However, the involvement of melatonin in thermotolerance and the underlying molecular mechanism in Arabidopsis were largely unknown. In this study, we found that the endogenous melatonin level in Arabidopsis leaves was significantly induced by heat stress treatment, and exogenous melatonin treatment conferred improved thermotolerance in Arabidopsis. The transcript levels of class A1 heat-shock factors (HSFA1s), which serve as the master regulators of heat stress responses, were significantly upregulated by heat stress and exogenous melatonin treatment in Arabidopsis. Notably, exogenous melatonin-enhanced thermotolerance was largely alleviated in HSFA1s quadruple knockout (QK) mutants, and HSFA1s-activated transcripts of heat-responsive genes (HSFA2, heat stress-associated 32 (HSA32), heat-shock protein 90 (HSP90), and 101 (HSP101)) might be contributed to melatonin-mediated thermotolerance. Taken together, this study provided direct link between melatonin and thermotolerance and indicated the involvement of HSFA1s-activated heat-responsive genes in melatonin-mediated thermotolerance in Arabidopsis.

Endoplasmic reticulum stress and oxidative stress are involved in ZnO nanoparticle-induced hepatotoxicity

Zinc oxide nanoparticles (Nano-ZnO) are widely used in sunscreens, clothes, medicine and electronic devices. However, the potential risks of human exposure and the potential for adverse health impacts are not well understood. Previous studies have demonstrated that exposure to Nano-ZnO caused liver damage and hepatocyte apoptosis through oxidative stress, but the molecular mechanisms that are involved in Nano-ZnO-induced hepatotoxicity are still unclear. Endoplasmic reticulum (ER) is sensitive to oxidative stress, and also plays a crucial role in oxidative stress-induced damage. Previous studies showed that ER stress was involved in many chemical-induced liver injuries. We hypothesized that exposure to Nano-ZnO caused oxidative stress and ER stress that were involved in Nano-ZnO-induced liver injury. To test our hypothesis, mice were gavaged with 200 mg/kg or 400 mg/kg of Nano-ZnO once a day for a period of 90 days, and blood and liver tissues were obtained for study. Our results showed that exposure to Nano-ZnO caused liver injury that was reflected by focal hepatocellular necrosis, congestive dilation of central veins, and significantly increased alanine transaminase (ALT) and aspartate transaminase (AST) levels. Exposure to Nano-ZnO also caused depletion of glutathione (GSH) in the liver tissues. In addition, our electron microscope results showed that ER swelling and ribosomal degranulation were observed in the liver tissues from mice treated with Nano-ZnO. The mRNA expression levels of ER stress-associated genes (grp78, grp94, pdi-3, xbp-1) were also up-regulated in Nano-ZnO-treated mice. Nano-ZnO caused increased phosphorylation of RNA-dependent protein kinase-like ER kinase (PERK) and eukaryotic initiation factor 2α (eIF2α). Finally, we found that exposure to Nano-ZnO caused increased ER stress-associated apoptotic protein levels, such as caspase-3, caspase-9, caspase-12, phosphorylation of JNK, and CHOP/GADD153, and up-regulation of pro-apoptotic genes (chop and bax). These results suggest that oxidative stress and ER stress-induced apoptosis are involved in Nano-ZnO-induced hepatotoxicity in mice.

ARTC1-mediated ADP-ribosylation of GRP78/BiP: a new player in endoplasmic-reticulum stress responses

Protein mono-ADP-ribosylation is a reversible post-translational modification of cellular proteins. This scheme of amino-acid modification is used not only by bacterial toxins to attack host cells, but also by endogenous ADP-ribosyltransferases (ARTs) in mammalian cells. These latter ARTs include members of three different families of proteins: the well characterised arginine-specific ecto-enzymes (ARTCs), two sirtuins, and some members of the poly(ADP-ribose) polymerase (PARP/ARTD) family. In the present study, we demonstrate that human ARTC1 is localised to the endoplasmic reticulum (ER), in contrast to the previously characterised ARTC proteins, which are typical GPI-anchored ecto-enzymes. Moreover, using the "macro domain" cognitive binding module to identify ADP-ribosylated proteins, we show here that the ER luminal chaperone GRP78/BiP (glucose-regulated protein of 78 kDa/immunoglobulin heavy-chain-binding protein) is a cellular target of human ARTC1 and hamster ARTC2. We further developed a procedure to visualise ADP-ribosylated proteins using immunofluorescence. With this approach, in cells overexpressing ARTC1, we detected staining of the ER that co-localises with GRP78/BiP, thus confirming that this modification occurs in living cells. In line with the key role of GRP78/BiP in the ER stress response system, we provide evidence here that ARTC1 is activated during the ER stress response, which results in acute ADP-ribosylation of GRP78/BiP paralleling translational inhibition. Thus, this identification of ARTC1 as a regulator of GRP78/BiP defines a novel, previously unsuspected, player in GRP78-mediated ER stress responses.

The effect of heat stress on skeletal muscle contractile properties

An elevated heat-shock protein (HSP) content protects cells and tissues, including skeletal muscles, from certain stressors. We determined if heat stress and the elevated HSP content that results is correlated with protection of contractile characteristics of isolated fast and slow skeletal muscles when contracting at elevated temperatures. To elevate muscle HSP content, one hindlimb of Sprague-Dawley rats (21-28 days old, 70-90 g) was subjected to a 15 min 42 °C heat-stress. Twenty-four hours later, both extensor digitorum longus (EDL) and soleus muscles were removed, mounted in either 20 °C or 42 °C Krebs-Ringer solution, and electrically stimulated. Controls consisted of the same muscles from the contra-lateral (non-stressed) hindlimbs as well as muscles from other (unstressed) animals. Isolated muscles were twitched and brought to tetanus every 5 min for 30 min. As expected, HSP content was elevated in muscles from the heat-stressed limbs when compared with controls. Regardless of prior treatment, both EDL and soleus twitch tensions were lower at 42 °C when compared with 20 °C. In addition, when incubated at 42 °C, both muscles showed a drop in twitch tension between 5 and 30 min. For tetanic tension, both muscles also showed an increase in tension between 5 and 30 min when stimulated at 20 °C regardless of treatment but when stimulated at 42 °C no change was observed. No protective effect of an elevated HSP content was observed for either muscle. In conclusion, although heat stress caused an elevation in HSP content, no protective effects were conferred to isolated contracting muscles.

Recombinant Leishmania infantum heat shock protein 83 for the serodiagnosis of cutaneous, mucosal, and visceral leishmaniases

Routine serological diagnoses for leishmaniases, except in visceral cases, are performed using whole-parasite antigens. We used enzyme-linked immunosorbent assay (ELISA) to evaluate the performance of Leishmania infantum rHsp83 compared with L. major-like total promastigote antigen in the diagnosis of cutaneous (CL), mucosal (ML), and visceral leishmaniases (VL). ELISA-rHsp83 was significantly more sensitive than ELISA–L. major-like when considering either CL/ML (P = 0.041) or all leishmaniasis patients (P = 0.013). When samples from other infectious disease patients were evaluated for cross-reactivity, ELISA-rHsp83 was more specific than ELISA–L. major-like, specifically for Chagas disease samples (P < 0.001). We also evaluated the anti-rHsp83 antibody titers months after treatment and observed no significant difference in ML (P = 0.607) or CL (P = 0.205). We recommend ELISA–L. infantum-rHsp83 as a routine confirmatory serological assay for the diagnosis of Leishmania infection because of the high sensitivity, the specificity, and the insignificant cross-reactivity with other infectious diseases.

Impact of exposure to low concentrations of nitric oxide on protein profile in murine and human pancreatic islet cells

Homeostatic levels of nitric oxide (NO) protect efficiently against apoptotic death in both human and rodent pancreatic β cells, but the protein profile of this action remains to be determined. We have applied a 2 dimensional LC-MS-MALDI-TOF/TOF-based analysis to study the impact of protective NO in rat insulin-producing RINm5F cell line and in mouse and human pancreatic islets (HPI) exposed to serum deprivation condition. 24 proteins in RINm5F and 22 in HPI were identified to undergo changes in at least one experimental condition. These include stress response mitochondrial proteins (UQCRC2, VDAC1, ATP5C1, ATP5A1) in RINm5F cells and stress response endoplasmic reticulum proteins (HSPA5, PDIA6, VCP, GANAB) in HPI. In addition, metabolic and structural proteins, oxidoreductases and chaperones related with protein metabolism are also regulated by NO treatment. Network analysis of differentially expressed proteins shows their interaction in glucocorticoid receptor and NRF2-mediated oxidative stress response pathways and eNOS signaling. The results indicate that exposure to exogenous NO counteracts the impact of serum deprivation on pancreatic β cell proteome. Species differences in the proteins involved are apparent.

Role of prostate apoptosis response 4 in translocation of GRP78 from the endoplasmic reticulum to the cell surface of trophoblastic cells

Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) molecular chaperone that belongs to the heat shock protein 70 family. GRP78 is also present on the cell surface membrane of trophoblastic cells, where it is associated with invasive or fusion properties of these cells. Impaired mechanism of GRP78 relocation from ER to the cell surface was observed in preeclamptic cytotrophoblastic cells (CTB) and could take part in the pathogenesis of preeclampsia. In this study, we have investigated whether prostate apoptosis response 4 (Par-4), a protein identified as a partner of GRP78 relocation to the cell surface in prostate cancer cells, is present in trophoblastic cells and is involved in the translocation of GRP78 to the cell surface of CTB. Par-4 is indeed present in trophoblastic cells and its expression correlates with expression of membrane GRP78. Moreover, overexpression of Par-4 led to an increase of cell surface expression of GRP78 and decreased Par-4 gene expression reduced cell surface localization of GRP78 confirming a role of Par-4 in relocation of GRP78 from ER to the cell surface. Accordingly, invasive property was modified in these cells. In conclusion, we show that Par-4 is expressed in trophoblastic cells and is involved in transport of GRP78 to the cell surface and thus regulates invasive property of extravillous CTB.

[Effects of erythropoietin on cardiomyocyte apoptosis and endoplasmic reticulum stress-related proteins in neonatal rats with asphyxia]

OBJECTIVE

To study the effects of erythropoietin (EPO) on cardiomyocyte apoptosis and endoplasmic reticulum stress (ERS)-related proteins, glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), in neonatal rats with asphyxia.

METHODS

A total of 120 newborn Sprague-Dawley rats (7 days old) were randomly divided into sham-operated (n=40), asphyxia (n=40) and EPO-treated asphyxia groups (n=40). A neonatal rat model of normobaric asphyxia was established in the asphyxia and EPO-treated asphyxia groups. The rats in the EPO-treated asphyxia group received intraperitoneal injection of recombinant human erythropoietin (500 U/mL) immediately after the model was established, while the other two groups received the same volume of normal saline (0.9%). Heart blood and myocardial tissue samples were collected from 8 rats in each group at 2, 6, 12, 24 or 48 hours after the model was established. Serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels were measured; cardiomyocyte apoptosis was evaluated, and expression of myocardial GRP78 and CHOP was measured.

RESULTS

Compared with the sham-operated and EPO-treated asphyxia groups, the asphyxia group had significantly increased serum CK and LDH levels, number of apoptotic cells, and expression of myocardial GRP78 and CHOP at each time point (P<0.01), and all the indices were significantly higher in the EPO-treated asphyxia group than in the sham-operated group (P<0.01). At 24 hours after asphyxia, the expression of myocardial CHOP was positively correlated with the myocardial apoptosis index (r=0.944, P<0.01).

CONCLUSIONS

EPO exerts a protective effect on the myocardium of neonatal rats with hypoxic-ischemic injury by regulating ERS-related proteins GRP78 and CHOP and reducing cardiomyocyte apoptosis.

Comparative proteomic analysis of off-type and normal phenotype somatic plantlets derived from somatic embryos of Feijoa (Acca sellowiana (O. Berg) Burret)

Morphological disorders in a relevant portion of emerged somatic embryos have been a limiting factor in the true-to-type plantlet formation in Acca sellowiana. In this sense, the present study undertook a comparison between normal phenotype and off-type somatic plantlets protein profiles by means of the 2-D DIGE proteomics approach. Off-type and normal phenotype somatic plantlets obtained at 10 and 20 days conversion were evaluated. Results indicated 12 exclusive spots between normal and off-type plantlets at 10 days conversion, and 17 exclusive spots at 20 days conversion. Also at 20 days conversion, 4 spots were differentially expressed, up- or down-regulated. Two proteins related to carbohydrate metabolism were only expressed in off-types at 10 days conversion, suggesting a more active respiratory pathway. A vicilin-like storage protein was only found in off-types at 20 days conversion, indicating that plantlets may present an abnormality in the mobilization of storage compounds, causing reduced vigor in the development of derived plantlets. The presence of heat shock proteins were only observed during formation of normal phenotype somatic plantlets, indicating that these proteins may be involved in normal morphogenesis of plantlets formed. These new findings shed light on possible genetic or epigenetic mechanisms governing A. sellowiana morphogenesis.

Exposure system and dosimetry for in vitro studies of biocompatibility of pulse-modulated RF signals of ultrahigh field MRI

A new setup for exposure of human cells in vitro at 37 °C to pulse-modulated 300 and 500 MHz signals of future magnetic resonance imaging (MRI) systems is designed, built up, and characterized. Two dipole antennas, specifically designed for ultrahigh field MRI, are used as radiating structures. The electromagnetic (EM) field distribution inside the incubator containing the cells is computed, and it is shown to be in a good agreement with measurements. The electric field at the cell level is quantified numerically. Local, 1-g average, and averaged over the culture medium volume SAR are provided along with the standard deviation values for each well. Temperature increments are measured inside the culture medium during the exposure using an optical fiber thermometer. Then, we identify the pulse parameters corresponding to the thermal threshold of 1 °C, usually considered as a threshold for thermally induced biological effects. For these parameters, the induction of heat shock proteins is assessed to biologically verify a potential thermal response of cells. The data demonstrate that, under the considered experimental conditions, exposure to pulse-modulated radiations emulating typical ultrahigh field MRI signals, corresponding to temperature increments below 1 °C, does not trigger any heat shock response in human brain cells.

Quantitative analyses of postmortem heat shock protein mRNA profiles in the occipital lobes of human cerebral cortices: implications in cause of death

Quantitative RNA analyses of autopsy materials to diagnose the cause and mechanism of death are challenging tasks in the field of forensic molecular pathology. Alterations in mRNA profiles can be induced by cellular stress responses during supravital reactions as well as by lethal insults at the time of death. Here, we demonstrate that several gene transcripts encoding heat shock proteins (HSPs), a gene family primarily responsible for cellular stress responses, can be differentially expressed in the occipital region of postmortem human cerebral cortices with regard to the cause of death. HSPA2 mRNA levels were higher in subjects who died due to mechanical asphyxiation (ASP), compared with those who died by traumatic injury (TI). By contrast, HSPA7 and A13 gene transcripts were much higher in the TI group than in the ASP and sudden cardiac death (SCD) groups. More importantly, relative abundances between such HSP mRNA species exhibit a stronger correlation to, and thus provide more discriminative information on, the death process than does routine normalization to a housekeeping gene. Therefore, the present study proposes alterations in HSP mRNA composition in the occipital lobe as potential forensic biological markers, which may implicate the cause and process of death.

Endoplasmic reticulum stress is involved in podocyte apoptosis induced by saturated fatty acid palmitate

BACKGROUND

Podocyte apoptosis is recently indicated as an early phenomenon of diabetic nephropathy. Pancreatic β-cells exposed to saturated free fatty acid palmitate undergo irreversible endoplasmic reticulum (ER) stress and consequent apoptosis, contributing to the onset of diabetes. We hypothesized that palmitate could induce podocyte apoptosis via ER stress, which initiates or aggravates proteinuria in diabetic nephropathy.

METHODS

Podocyte apoptosis was detected by 4',6-diamidio-2-phenylindole (DAPI) stained apoptotic cell count and Annexin V-PI stain. The expressions of ER molecule chaperone glucose-regulated protein 78 (GRP78), indicators of ER-associated apoptosis C/EBP homologous protein (CHOP), and Bcl-2 were assayed by Western blotting and real-time PCR. GRP78 and synaptopodin were co-localized by immunofluorescence stain.

RESULTS

Palmitate significantly increased the percentage of cultured apoptotic murine podocytes time-dependently when loading 0.75 mmol/L (10 hours, 13 hours, and 15 hours compared with 0 hour, P < 0.001) and dose-dependently when loading palmitate ranging from 0.25 to 1.00 mmol/L for 15 hours (compared to control, P < 0.001). Palmitate time-dependently and dose-dependently increased the protein expression of GRP78 and CHOP, and decreased that of Bcl-2. Palmitate loading ranging from 0.5 to 1.0 mmol/L for 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to control (P < 0.001), with the maximum concentration being 0.75 mmol/L. Palmitate 0.5 mmol/L loading for 3 hours, 8 hours, and 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to 0 hour (P < 0.001), with the maximum effect at 3 hours. Confocal microscopy demonstrated that GRP78 expression was significantly increased when exposed to 0.5 mmol/L of palmitate for 8 hours compared to control.

CONCLUSION

Palmitate could induce podocyte apoptosis via ER stress, suggesting podocyte apoptosis and consequent proteinuria caused by lipotoxic free fatty acid could be ameliorated by relief of ER stress.

Comprehensive proteome analysis in Cenococcum geophilum Fr. as a tool to discover drought-related proteins

Cenococcum geophilum is a widely distributed ectomycorrhizal fungus potentially playing a significant role in resistance and resilience mechanisms of its tree hosts exposed to drought stress. In this study, we performed a large scale protein analysis in pure cultures of C. geophilum in order to gain first global insights into the proteome assembly of this fungus. Using 1-D gel electrophoresis coupled with ESI-MS/MS, we indentified 638 unique proteins. Most of these proteins were related to the metabolic and cellular processes, and the transport machinery of cells. In a second step, we examined the influence of water deprivation on the proteome of C. geophilum pure cultures at three time points of gradually imposed drought. The results indicated that 12 proteins were differentially abundant in mycelia subjected to drought compared to controls. The induced responses in C. geophilum point towards regulation of osmotic stress, maintainance of cell integrity, and counteracting increased levels of reactive oxygen species formed during water deprivation.

Effects of chronic heat stress on the expressions of heat shock proteins 60, 70, 90, A2, and HSC70 in the rabbit testis

Few studies have focused on the expression of heat shock proteins (HSPs) after chronic heat stress. The objective of this study was to investigate the effect of chronic high temperature-humidity index treatment on the expressions of HSP60, HSP70, HSP90, HSPA2 and HSC70, in the Rex rabbit testis and the expressions of these proteins after recovery from the chronic heat shock. Thirty mature male rabbits of the same age were randomly divided into three groups: control, heat stress, and recovery. The western blot results showed that the expressional levels of HSP60, HSP90, and HSC70 increased significantly and HSPA2 was elevated slightly after a 9-week heat treatment. HSP70 was absent in the control testis and had a high level of expression after heat stress. All of these proteins partially reverted back to normal levels after a 9-week recovery. The immunohistochemical results indicated that the expression patterns of HSP60, HSP90, HSPA2, and HSC70 did not change.

Proteomics of rice in response to heat stress and advances in genetic engineering for heat tolerance in rice

Rice is the most important food crop worldwide. Global warming inevitably affects the grain yields of rice. Recent proteomics studies in rice have provided evidence for better understanding the mechanisms of thermal adaptation. Heat stress response in rice is complicated, involving up- or down-regulation of numerous proteins related to different metabolic pathways. The heat-responsive proteins mainly include protection proteins, proteins involved in protein biosynthesis, protein degradation, energy and carbohydrate metabolism, and redox homeostasis. In addition, increased thermotolerance in transgenic rice was obtained by overexpression of rice genes and genes from other plants. On the other hand, heterologous expression of some rice proteins led to enhanced thermotolerance in bacteria and other easily transformed plants. In this paper, we review the proteomic characterization of rice in response to high temperature and achievements of genetic engineering for heat tolerance in rice.

Identification and validation of rice reference proteins for western blotting

Studies of rice protein expression have increased considerably with the development of rice functional genomics. In order to obtain reliable expression results in western blotting, information on appropriate reference proteins is necessary for data normalization. To date, no published study has identified and systematically validated reference proteins suitable for the investigation of rice protein expression. In this study, nine candidate proteins were selected and their specific antibodies were obtained through immunization of rabbits with either recombinant proteins expressed in Escherichia coli or synthesized peptides. Western blotting was carried out to detect the expression of target proteins in a set of 10 rice samples representing different rice tissues/organs at different developmental stages. The expression stability of the proteins was analysed using geNorm and Microcal Origin 6.0 software. The results indicated that heat shock protein (HSP) and elongation factor 1-α (eEF-1α) were the most constantly expressed among all rice proteins tested throughout all developmental stages, while the proteins encoded by conventional internal reference genes fluctuated in amount. Comparison among the profiling of translation and transcription [expressed sequence tags (EST) and massively parallel signature sequencing (MPSS)] revealed that a correlation existed. Based on the standard curves derived from the antigen-antibody reaction, the concentrations of HSP and eEF-1α proteins in rice leaves were ∼0.12%. Under the present experimental conditions, the lower limits of detection for HSP and eEF-1α proteins in rice were 0.24 ng and 0.06 ng, respectively. In conclusion, the reference proteins selected in this study, and the corresponding antibodies, can be used in qualitative and quantitative analysis of rice proteins.

Capturing cold-stress-related sequence diversity from a wild relative of common bean (Phaseolus angustissimus)

One restriction to the cultivation of common bean, Phaseolus vulgaris L., is its limited tolerance to low temperatures. In the present study, subtraction suppression hybridization was employed to enrich for stress responsive genes in both a chilling-susceptible common bean and a relatively more chilling-tolerant wild bean species, Phaseolus angustissimus. For each species, approximately 11 000 expressed sequence tags were generated. Comparative sequence analysis of the EST collection with the available annotated genome sequences of the model Fabaceae species Medicago truncatula and Glycine max identified protein homologues for approximately 65% and 80% of the Phaseolus sequences, respectively. This difference reflects the closer phylogenetic relationship between the genera Phaseolus and Glycine compared with Medicago. Annotation of the Phaseolus sequences was facilitated through this comparative analysis and indicated that several heat shock proteins, cytochrome P450s, and DNA binding factors were uniquely found among the sequences from the wild species P. angustissimus. The Phaseolus sequences have been made available on a GBrowse implementation using M. truncatula as the reference genome, providing rapid access to the sequence data and associated comparative genome data.

Differential levels of stress proteins (HSPs) in male and female Daphnia magna in response to thermal stress: a consequence of sex-related behavioral differences?

In two independent experiments, we compared: (1) water depth selection (and accompanying temperature selection) by male and female Daphnia magna under different kinds of environmental stress, including the presence of filamentous cyanobacteria, the risk of predation from fish, and the presence of toxic compounds; and (2) sex-dependent production of heat shock proteins (HSP60, 70, and 90) in response to a sudden change in temperature. Male D. magna selected deep water strata, which offer a relatively stable environment, and thereby avoided the threat of predation and the presence of toxic compounds in surface waters. Correlated with this behavior, males reduce their molecular defenses against stress, such as the production of heat shock proteins (HSPs), and do not maintain the physiological machinery that triggers an increase in HSP levels in response to stress. In contrast, female D. magna actively select habitats that offer optimal conditions for growth and production of offspring. Consequently, females are exposed to variable environmental conditions that may be associated with increased stress. To permit survival in these different habitats, D. magna females require molecular mechanisms to protect their cells from rapid changes in stress levels. Thus, they maintain high constitutive levels of the heat shock proteins from HSP 60, 70, and 90 families, and they have the potential to further enhance the production of the majority of these proteins under stress conditions. The results of this study indicate that the separate habitats selected by male and female D. magna result in different patterns of HSP production, leading us to hypothesize that that male and female Daphnia magna adopt different strategies to maximize the fitness of the species.

GRP78/BiP modulation of GRP78/BiP in altering sensitivity to chemotherapy

The glucose-regulated protein 78 (GRP78) is a key regulator of the endoplasmic reticulum (ER) stress response. This chapter discusses how GRP78 may be measured in vitro and in vivo. Because of the authors' expertise and experience with brain tumors, most of our work on GRP78 has focused on malignant gliomas. Here, we present our methodology for determining GRP78 in vitro using glioma cell lines and primary cell cultures, and in measuring GRP78 expression in tissue sections from rodent glioma models and human brain tumors. After discussion of measurement of GRP78 levels, modulation of GRP78 in vitro is demonstrated using glioma cell lines. Lastly, in vivo modulation of GRP78 levels via chemotherapy is determined using intracranial rodent models.

Stress-related proteins compared in diapause and in activated, anoxic encysted embryos of the animal extremophile, Artemia franciscana

Previous work indicated similarities between diapause and anoxic quiescence in encysted embryos (cysts) of the brine shrimp Artemia franciscana. That possibility was examined further in the present study through an immunochemical study of the following stress-related proteins in low speed supernatants and pellets: hsc70, artemin, p26, hsp21, LEA Group 1 protein and p8. Changes in the amounts and locations of these proteins occurred during the initial period after release of diapause cysts from females, and after activated (diapause-terminated) cysts were made anoxic. However, with the passage of incubation time the patterns seen in both kinds of cysts were more similar than different, lending further support to the possibility that activated anoxic embryos retain many of the mechanisms operative in the previous diapause condition.

Influence of yeast macromolecules on sweetness in dry wines: role of the saccharomyces cerevisiae protein Hsp12

Yeast autolysis during lees contact influences the organoleptic properties of wines especially by increasing their sweet taste. Although observed by winemakers, this phenomenon is poorly explained in enology. Moreover, the compounds responsible for sweetness in wine remain unidentified. This work provides new insights in this way by combining sensorial, biochemical and genetic approaches. First, we verified by sensory analysis that yeast autolysis in red wine has a significant effect on sweetness. Moderate additions of ethanol or glycerol did not have the same effect. Second, a sapid fraction was isolated from lees extracts by successive ultrafiltrations and HPLC purifications. Using nano-LC-MS/MS, peptides released by the yeast heat shock protein Hsp12p were distinctly identified in this sample. Third, we confirmed the sweet contribution of this protein by sensorial comparison of red wines incubated with two kinds of yeast strains: a wild-type strain containing the native Hsp12p and a deletion mutant strain that lacks the Hsp12p protein (Δ°HSP12 strain). Red wines incubated with wild-type strain showed a significantly higher sweetness than control wines incubated with Δ°HSP12 strains. These results demonstrated the contribution of protein Hsp12p in the sweet perception consecutive to yeast autolysis in wine.

[Screen and identify of differential proteins expressed in the placenta of Down's syndrome]

OBJECTIVE

To discuss protein marks expressed differentially in placenta of Down's syndrome by means of proteomics.

METHODS

We collected placenta of 18 patients (from March 2009 to December 2009 at Beijing Obstetrics and Gynecology Hospital), and divided them into two groups, one was 10 patients with fetal Down's syndrome, the other was normal pregnancies (normal chromosome) with other diseases. We separated proteins expressed in placentas of two groups by two-dimensional difference gel electrophoresis (2D-DIGE), and then analyzed the differential protein spots by software Decyder 6.5, then, spots differentially expressed by 1.5 fold or more were analyzed by matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). In the end, the differential expressional levels of partially identified proteins were validated by western blot analysis.

RESULTS

(1) Differential proteins of two groups protein spots of placentas separated by 2D-DIGE were analyzed by software Decyder 6.5 (these colored lights scattered in the image were protein spots), a total of 56 spots out of 352 were differentially expressed (P < 0.05) in two groups. We analyzed 17 protein spots (12 protein spots were over-expressed and 5 protein spots were down-expressed) differentially expressed by 1.5 fold or more by MALDI-TOF-MS. (2) Protein matching after searching protein database, 17 protein spots turn out to be 10 proteins. Four kinds [superoxide dismutase 1 (SOD1), peroxiredoxin 6 (PRDX6), heat shock protein 27 (HSP27), endoplasmic reticulum protein 29 (ERP29)] of them were validated by western blot analysis, the group of fetal Down's syndrome were 0.74 ± 0.12, 0.29 ± 0.10, 0.53 ± 0.16, 0.20 ± 0.09, the group of normal pregnancies were 0.51 ± 0.08, 0.34 ± 0.16, 0.18 ± 0.07, 0.35 ± 0.09, the results confirmed the observed changes in proteomics.

CONCLUSIONS

Compared with normal pregnancies, there were differential proteins expressed in placenta of Down's syndrome. This approach might provide new screening markers in use for prediction of Down's syndrome, however, further study should be done to make these 4 proteins (SOD1, HSP27, ERP29, PRDX6) be new screening markers.

[Expression of GRP78 and GRP94 in the liver tissues and their clinicopathological significance in children with hepatoblastoma]

OBJECTIVE

To study the expression of glucose-regulated protin 78 (GRP78) and glucose-regulated protin 94 (GRP94) in the liver tissues from children with hepatoblastoma (HB) and to investigate the possible clinicopathological values of GRP78 and GRP94 in HB.

METHODS

Liver tissue specimens from 15 children with HB and 10 specimens of normal liver tissues were obtained. EnVison immunohistochemistry was used to detect the expression of GRP78 and GRP94 in the conventional paraffin-embedded liver sections.

RESULTS

The positive rates of GRP78 expression (53% vs 10%; P<0.05) and GRP94 expression (60% vs 10%; P<0.05) in HB liver tissues were significantly higher than those in the normal liver tissues. The positive rates of GRP78 expression in the cases without lymphnode metastasis or in clinical stage I-II were significantly lower than those in the cases with lymphnode metastasis or in clinical stage III-IV (P<0.05). GRP94 showed a decreased tendency of positive expression in the cases without lymphnode metastasis or in clinical stage I-II when compared with the cases with lymphnode metastasis or in clinical stage III-IV, although there were no statistical differences between them.

CONCLUSIONS

GRP78 and GRP94 expression might play important roles in the pathogenesis and progression of pediatric HB.

[Study on rapid detection techniques of PCR-ELISA for Listeria monocytogenes]

OBJECTIVE

To develop rapid PCR-ELISA methods for detecting Listeria monocytogenes, and detect food samples artificially contaminated with Listeria monocytogenes.

METHODS

Specific primers for Listeria monocytogenes pathogenic gene hlyA were selected based on the Genbank data by using molecular biological software DNAman6.0. Digoxigenin-labeled hlyA fragments were obtained by using commercial kit. Specific capture probes were obtained by comparing bacterial pathogenic gene sequences in the Genbank. PCR-ELISA methods were developed and the Listeria monocytogenes isolates with different serotypes were detected. The sensitivity of PCR and PCR-ELISA was determined by artificially inoculating Listeria monocytogenes strains in milk.

RESULTS

It took 6 hours to detect Listeria monocytogenes in food samples by PCR-ELISA. The accordance rate to the bacteriological method was 100%. After 12 h pre-enrichment, the detection limit of PCR-ELISA method was 1 CFU/25 ml milk. The sensitivity of PCR-ELISA method was 10-100 times as PCR.

CONCLUSION

The PCR-ELISA method for rapidly detecting Listeria monocytogenes was established. The sensitivity, specificity and reliability of the method proved to be good. It would be valuable to improve the precaution and prediction abilities of food-borne diseases and enhance the chronergy and accuracy of detection method.

Peripheral leukocyte response to oncological radiotherapy: Expression of heat shock proteins

PURPOSE

To study Heat Shock Proteins (HSP) expression in patients subjected to radiotherapy and their potential use as biomarkers for radiation tolerance. An evaluation is also made of whether irradiated volume is critical to the outcome of normal tissue injury using polymorphonuclear neutrophils as biosensors, and whether HSP antibodies (Ab) may be involved in post-radiotherapy disease.

MATERIAL AND METHODS

Twelve patients receiving the same total dose of radiotherapy, but in three different volumes, and four healthy volunteers used as controls were analysed. hsp27 and 70i mRNA were determined by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and Southern-blot, HSP by flow cytometry, and HSP-Ab by Enzyme-linked Immnoadsorbent Assay (ELISA). The clinical protocol included radiation related toxicity based on clinical and analytical scales.

RESULTS

Radiotherapy caused hsp downregulation, maximum in patients with the largest irradiated volumes, and a decrease in intracellular HSP content. Patients with greatest intraleukocyte HSP levels before treatment suffered more severe radiation morbidity. Patients with endocrine neoplasms presented the highest HSP-Ab titers.

CONCLUSIONS

Radiotherapy downregulates hsp27 and 70i, which would enhance radiosensitivity. HSP content prior to treatment is suggested as a prognostic biomarker for radiation tolerance, with circulating leukocytes as biosensors. HSP-Ab may be biomarkers of tumor disease, but do not seem to be involved in the morbidity of acute post-radiotherapy disease, which is closely related to the volumes irradiated.

Proteomic analysis of the nuclear matrix in the early stages of rat liver carcinogenesis: identification of differentially expressed and MAR-binding proteins

Tumor progression is characterized by definite changes in the protein composition of the nuclear matrix (NM). The interactions of chromatin with the NM occur via specific DNA sequences called MARs (matrix attachment regions). In the present study, we applied a proteomic approach along with a Southwestern assay to detect both differentially expressed and MAR-binding NM proteins, in persistent hepatocyte nodules (PHN) in respect with normal hepatocytes (NH). In PHN, the NM undergoes changes both in morphology and in protein composition. We detected over 500 protein spots in each two dimensional map and 44 spots were identified. Twenty-three proteins were differentially expressed; among these, 15 spots were under-expressed and 8 spots were over-expressed in PHN compared to NH. These changes were synchronous with several modifications in both NM morphology and the ability of NM proteins to bind nuclear RNA and/or DNA containing MARs sequences. In PHN, we observed a general decrease in the expression of the basic proteins that bound nuclear RNA and the over-expression of two species of Mw 135 kDa and 81 kDa and pI 6.7-7.0 and 6.2-7.4, respectively, which exclusively bind to MARs. These results suggest that the deregulated expression of these species might be related to large-scale chromatin reorganization observed in the process of carcinogenesis by modulating the interaction between MARs and the scaffold structure.

Identification of 5-fluorouracil response proteins in colorectal carcinoma cell line SW480 by two-dimensional electrophoresis and MALDI-TOF mass spectrometry

Colorectal cancer (CRC) is the second most prevalent cause of cancer-related deaths in the Western world. 5-Fluorouracil (5-FU) is a standard chemotherapeutic drug to treat CRC. However, the response rate is less than 20% and patients who have responded to 5-FU may become resistant. Therefore there is an urgent need to examine the 5-FU response proteins so that patients with no response to 5-FU can change to other treatment strategies promptly. In this study, the proteomic expression profile in a CRC cell line SW480 before and after 5-FU treatment was examined using 2-dimensional electrophoresis technology. Fourteen proteins with differential expression were identified using mass spectrometry and 7 of them were validated using immunocytochemical (ICC) staining. Protein identification indicated that cyclophilin A, cytokeratin 19 (CK19), cytokeratin 8 (CK8), ras-related nuclear protein, heat shock protein 27 (hsp27) and peroxiredoxin 6 (Prx 6) were upregulated whereas heat shock protein 60 (hsp60), cytokeratin 18 (CK18), cytokeratin 9 (CK9), carbamoylphosphate synthetase I, alpha-enolase, heat shock protein 70 (hsp70), nm23 and beta-actin were down-regulated. Seven of the 14 proteins detected were validated by ICC staining, which showed that the expression of hsp27, Prx 6 and hsp70 correlated with that from proteomics profiling. Our results suggest that hsp27, Prx 6 and hsp70 are potential 5-FU response proteins and they may represent potential targets for further evaluation in other 5-FU-sensitive and -resistant CRC cell lines.

Irradiation leads to apoptosis of Kupffer cells by a Hsp27-dependant pathway followed by release of TNF-alpha

In a previous publication, we were able to show that irradiation of Kupffer cells, the liver resident macrophages, leads to an increased TNF-alpha concentration in the culture medium. The pathomechanisms underlying this phenomenon, however, remained to be elucidated. Here, we show that following irradiation of Kupffer cells, the apoptosis rate increased drastically within 48 h. At the same time, the total TNF-alpha concentration in cell lysates of Kupffer cells attached to the culture plate decreased. However, normalization of the TNF-alpha concentration with respect to cell number revealed that TNF-alpha concentration per attached cell remained constant during the observation period. Western blot analysis showed that heat shock protein 27 (Hsp27) is strongly downregulated and bax is upregulated in irradiated Kupffer cells as compared to sham-irradiated cells. Overexpression of Hsp27 in Kupffer cells was shown to prevent the effect of irradiation on bax expression, apoptosis and, at the same time, on increase of TNF-alpha concentration in the Kupffer cell medium. We conclude that irradiation of Kupffer cells leads to apoptosis because of downregulation of Hsp27 and consecutive upregulation of bax expression. Furthermore, we suggest that apoptosis of Kupffer cells leads to an increase of TNF-alpha concentration in the culture medium which may be due to cell death rather than active release or synthesis.

Use of primers based on the heat shock protein genes hsp70, hsp40, and hsp10, for the detection of bovine mastitis pathogens Streptococcus agalactiae, Streptococcus uberis and Streptococcus bovis

Streptococcus agalactiae, Streptococcus uberis, and Streptococcus bovis are three of the major pathogens which cause mastitis in dairy herds. Since conventional methods for the detection of these mastitis pathogens are laborious and time-consuming, rapid methods are needed. With an attempt to know if heat shock protein (HSP) genes other than HSP60 gene, could be used for PCR primer designing, in this study, we tried to design PCR primers based on the heat shock protein genes hsp70, hsp40, and hsp10 for the specific detection of S. agalactiae, S. uberis, and S. bovis, respectively. Using these primers, all the randomly selected target strains could be specifically detected. Bacterial species other than the target organisms, including strains of other Streptococcus spp., and strains of non-Streptococcus spp., would not generate any false positive results. As these PCR primers were used for direct detection of mastitis pathogens, the detection limit was N (N=1-9) x 10(3)CFU/ml of cell dilutions. If a 10h pre-enrichment step was performed, the detection limit was N x 10(0)CFU/ml. Thus, these primers could be used for the specific and sensitive detection of bovine mastitis bacteria.

Application of heat shock protein assay and proteome assay to water from wastewater treatment plant

In this study we applied bioassay using Chinese hamster ovary (CHO) cells with a heat shock protein (HSP) 47 promoter to the effluent of the wastewater treatment plants in Sapporo and we observed the statistically significant HSP production. This implied the effluent contained some organic matter which can stress the CHO cells. To investigate the possible causes of the toxicity of the effluent, we applied the assay to the rejected water from the sludge treatment plant, the mixtures of sewage and rejected water. The evolution of HSP production during the aerobic decay process and thickening process of sludge was also examined. These assay results showed that dissolved microbial products generated and/or released from activated sludge during its decay process in the aeration tank and during thickening and dewatering process in the sludge treatment train contributed to develop HSP production. The proteomics analysis was also applied to the effluent and detected the production of elongation factor 1beta. This result implies that the effluent from wastewater treatment plants may cause changes in cell proteins involved in allergic reaction.

Proteomics finding heat shock protein 27 as a biomarker for resistance of pancreatic cancer cells to gemcitabine

Pancreatic cancer remains a devastating disease and >96% of patients with pancreatic cancer do not survive for more than 5 years. Gemcitabine (2'-deoxy-2'-difluoro-deoxycytidine: Gemzar) appears to be the only clinically effective drug for pancreatic cancer, but it has little impact on outcome. Proteomic analysis of gemcitabine-sensitive cells (KLM1) and resistant pancreatic cells (KLM1-R) was performed to identify target proteins of the gemcitabine. We found seven proteins, HSP27, peroxiredoxin 2, endoplasmic reticulum protein ERp29 precursor, 6-phosphogluconolactonase, triosphospate isomerase, alpha enolase, and nucleophosmine that could play a role in determining the sensitivity of pancreatic cancer to gemcitabine. We knocked down HSP27 in KLM1-R and the sensitivity to gemcitabine was restored. In addition, increased HSP27 expression in tumor specimens was related to higher resistibility to gemcitabine in patients of pancreatic cancer. HSP27 may play an important role in the resistibility to gemcitabine, and it could also be a possible biomarker for predicting the response of pancreatic cancer patients to treatment with gemcitabine.

GRP78 as a novel predictor of responsiveness to chemotherapy in breast cancer

The discovery of predictive factors for chemoresistance is critical for improving adjuvant therapy for cancer patients. The 78-kDa glucose-regulated protein (GRP78), widely used as an indicator of the unfolded protein response (UPR), is induced in the tumor microenvironment. In vitro studies suggest that GRP78 confers chemoresistance to topoisomerase inhibitors, such as Adriamycin (doxorubicin). Here, we report on a retrospective cohort study of 127 stage II and III breast cancer patients who were treated with Adriamycin-based chemotherapy. Archival tumor specimens were available for analysis and the relationship of GRP78 expression level to "time to recurrence" (TTR), used as a surrogate marker for drug resistance, was examined. Our data show that 67% of the study subjects expressed high level of GRP78 in their tumors before the initiation of chemotherapy and suggest an association between GRP78 positivity and shorter TTR [hazard ratio (HR), 1.78; P = 0.16]. Interestingly, subgroup analysis reveals that the HR for the GRP78-positive group increased significantly among patients who did not receive further taxane treatment (HR, 3.00; P = 0.022) and among mastectomy patients (HR, 3.33; P = 0.027). The HR was even stronger among mastectomy patients who did not receive further taxane treatment (HR, 4.82; P = 0.010). The use of GRP78 as a predictor for chemoresponsiveness and the potential interaction of GRP78 and/or the UPR pathways with taxanes warrant larger studies.

Photodynamic therapy resistant human colon carcinoma HT29 cells show cross-resistance to UVA but not UVC light

The isolation of photodynamic therapy (PDT)-resistant HT29 human colon adenocarcinoma cells has been reported previously. These PDT-resistant variants show increased expression of the Hsp27 and BNip3 proteins and a decreased expression of mutant p53 protein compared with parental HT29 cells. Because mutant p53 and increased expression of Hsp27 have been associated with resistance to various chemotherapeutic agents, whereas BNip3 is a potent inducer of apoptosis, we were interested in determining whether these PDT-resistant cells were cross-resistant to other cytotoxic agents. In the present report, we examined the colony survival of the PDT-resistant HT29 variants and several other clonal variants of HT29 cells to ultraviolet light (UV) treatment. The HT29 PDT-resistant variants showed cross-resistance to long-wavelength UVA (320-400 nm) but not to short-wavelength UVC (200-280 nm) light. Cell sensitivity to UVA or UVC was then correlated with Hsp27, BNip3 and mutant p53 protein levels in the PDT-resistant variants as well as in several clonal variants of HT29 cells that express different levels of Hsp27, BNip3 and mutant p53. We show that increased expression of Hsp27 and BNip3 and decreased expression of mutant p53 correlated with increased resistance to UVA. In contrast, increased expression of Hsp27 and BNip3 correlated with increased sensitivity to UVC, whereas increased expression of mutant p53 showed no significant correlation with sensitivity to UVC. These results suggest that the PDT-resistant HT29 cell variants are differentially sensitized to UVA compared with UVC due, in part at least, through the altered expression levels of BNip3, Hsp27 and mutant p53.

Expression of heat shock proteins and stress fiber formation within the arterial vascular tree of adult rats under normal physiological conditions

In this study, we investigated heat shock protein (HSP) expression and stress fiber (SF) formation in endothelial cells (ECs) within the arterial vascular tree of adult rats under normal physiological conditions. Using quantitative immunofluorescence microscopy, we found no significant differences in expression of HSPs 25, 60, 70, and 90 among ECs in the straight portions of rat arteries. In these regions, ECs appeared spindle-shaped and contained short bundles of central SFs. In contrast, ECs in the curved portions or the branch sites of the arteries, exhibited striking differences in HSP expression. ECs with higher HSP expression were localized at the lesser curvature in the curved portions or the distal site of the branch ostia. Moreover, the ECs became polygonal and contained irregular central SFs at the lesser curvature. At the branch sites, downstream ECs became spear-shaped and contained long, thick bundles of central SFs. Curved portions or branch sites are the regions of disturbed flow at which early atherosclerotic lesions are often found. Our results demonstrate these positional differences in HSP expression associated with changes in SF formation within the arterial vascular tree under non-pathological conditions. Our study provides basic information for understanding stress responses via HSP expression and SF formation in vascular ECs and the pathogenesis of atherosclerotic disease.

IgG antibody patterns in aqueous humor of patients with primary open angle glaucoma and pseudoexfoliation glaucoma

PURPOSE

There has been growing body of evidence indicating an immunological component in the pathogenesis of glaucoma. Several studies found specific antibodies in sera of glaucoma patients. Recently, we detected antibody profiles in aqueous humor of patients with normal tension glaucoma that showed significant differences when compared to control subjects. The aim of this study was to compare the IgG antibody patterns against retinal antigens in aqueous humor of patients with primary open angle glaucoma, pseudoexfoliation glaucoma, and control subjects then to identify some of the important biomarkers of this study.

METHODS

Aqueous humor of 44 patients was analyzed: 15 patients with primary open angle glaucoma (POAG), 14 patients with pseudoexfoliation glaucoma (PEX), and 15 control subjects (CO). The aqueous was tested against western blots of bovine retinal antigens. The IgG antibody patterns were analyzed by multivariate statistical techniques. Some of the important biomarkers were identified via mass spectrometry (Maldi-TOFTOF).

RESULTS

All patients showed complex patterns of IgG antibodies against retinal antigens. The discriminant analysis revealed a statistically significant difference between the antibody profiles of the POAG and the CO group (p=0.00018). There was also a statistically significant difference between the antibody profiles of the PEX and the CO group (p=0.0013). Not only were up-regulations in the glaucoma groups observed, compared to controls, but also down-regulations. There was no significant difference between the antibody patterns of the POAG and PEX group. The identified biomarkers included heat shock protein 27, alpha-enolase, actin, and GAPDH.

CONCLUSIONS

We could show significant differences between the IgG antibody profiles of the glaucoma groups (PEX and POAG) and controls. The analysis of intraocular antibodies could provide further hints for autoimmune involvement in glaucoma.