Zinc alleviates the heat stress of primary cultured hepatocytes of broiler embryos via enhancing the antioxidant ability and attenuating the heat shock responses

Zinc(Zn)has been shown to attenuate the adverse effects of heat stress on broilers,but the mechanisms involving this process remain unclear.We aimed to investigate possible protective mechanisms of Zn on primary cultured hepatocytes of broiler embryos subjected to heat stress.Three experiments were conducted.In Exp.1,hepatocytes were treated with 0,50,100,200,or 400μmol/L added Zn as inorganic Zn sulfate(iZn)for 12,24 or 48 h.In Exp.2,cells were exposed to 40℃(a normal temperature[NT])and 44℃(a high temperature[HT])for 1,2,4,6,or 8 h.In Exp.3,cells were preincubated with 0 or 50μmol/L Zn as iZn or organic Zn lysine chelate(oZn)for 8 h under NT,and then incubated with the same Zn treatments under NT or HT for 4 or 6 h.The biomarkers of antioxidative status and heat stress in cells were measured.The results in Exp.1 indicated that 50μmol/L Zn and 12 h incubation were the optimal conditions for increasing antioxidant ability of hepatocytes.In Exp.2,the 4 or 6 h incubation under HT was effective in inducing heat shock responses of hepatocytes.In Exp.3,HT elevated(P<0.01)malondialdehyde content and expressions of heat shock protein 70(HSP70)mRNA and protein,as well as HSP90 mRNA.However,Zn supplementation increased(P<0.05)copper zinc superoxide dismutase(CuZnSOD)activity and metallothionein mRNA expression,and effectively decreased(P<0.05)the ex-pressions of HSP70 mRNA and protein,as well as HSP90 mRNA.Furthermore,oZn was more effective(P<0.05)than iZn in enhancing CuZnSOD activity of hepatocytes under HT.It was concluded that Zn(especially oZn)could alleviate heat stress of broiler hepatocytes via enhancing their antioxidant ability and attenuating heat shock responses.

Subversion of cellular stress responses by poxviruses

Cellular stress responses are powerful mechanisms that prevent and cope with the accumulation of macromolecular damage in the cells and also boost host defenses against pathogens. Cells can initiate either protective or destructive stress responses depending, to a large extent, on the nature and duration of the stressing stimulus as well as the cell type. The productive replication of a virus within a given cell places inordinate stress on the metabolism machinery of the host and, to assure the continuity of its replication, many viruses have developed ways to modulate the cell stress responses. Poxviruses are among the viruses that have evolved a large number of strategies to manipulate host stress responses in order to control cell fate and enhance their replicative success. Remarkably, nearly every step of the stress responses that is mounted during infection can be targeted by virally encoded functions. The fine-tuned interactions between poxviruses and the host stress responses has aided virologists to understand specific aspects of viral replication; has helped cell biologists to evaluate the role of stress signaling in the uninfected cell; and has tipped immunologists on how these signals contribute to alert the cells against pathogen invasionand boost subsequent immune responses. This review discusses the diverse strategies that poxviruses use to subvert host cell stress responses.

Induction of Antioxidant and Heat Shock Protein Responses During Torpor in the Gray Mouse Lemur, Microcebus murinus

A natural tolerance of various environmental stresses is typically supported by various cytoprotective mechanisms that protect macromolecules and promote extended viability. Among these are antioxidant defenses that help to limit damage from reactive oxygen species and chaperones that help to minimize protein misfolding or unfolding under stress conditions. To understand the molecular mechanisms that act to protect cells during primate torpor, the present study characterizes antioxidant and heat shock protein（HSP） responses in various organs of control（aroused）and torpid gray mouse lemurs, Microcebus murinus. Protein expression of HSP70 and HSP90 a was elevated to 1.26 and 1.49 fold, respectively, in brown adipose tissue during torpor as compared with control animals, whereas HSP60 in liver of torpid animals was 1.15 fold of that in control（P 〈 0.05）. Among antioxidant enzymes, protein levels of thioredoxin 1 were elevated to 2.19 fold in white adipose tissue during torpor, whereas Cu–Zn superoxide dismutase 1 levels rose to 1.1 fold in skeletal muscle（P 〈 0.05）. Additionally, total antioxidant capacity was increased to 1.6 fold in liver during torpor（P 〈 0.05）, while remaining unchanged in the five other tissues. Overall, our data suggest that antioxidant and HSP responses are modified in a tissue-specific manner during daily torpor in gray mouse lemurs. Furthermore, our data also show that cytoprotective strategies employed during primate torpor are distinct from the strategies in rodent hibernation as reported in previous studies.

Increased expression of heat shock protein 70 and heat shock factor 1 in chronic dermal ulcer tissues treated with laser-aided therapy

Background Chronic dermal ulcers are also referred to as refractory ulcers. This study was conducted to elucidate the therapeutic effect of laser on chronic dermal ulcers and the induced expression of heat shock factor 1 （HSF1） and heat shock protein 70 （HSP70） in wound tissues. Methods Sixty patients with 84 chronic dermal ulcers were randomly divided into traditional therapy and laser therapy groups. Laser treatment was performed in addition to traditional therapy in the laser therapy group. The treatment efficacy was evaluated after three weeks. Five tissue sections of healing wounds were randomly collected along with five normal skin sections as controls. HSP70-positive cells from HSP70 immunohistochemical staining were counted and the gray scale of positive cells was measured for statistical analysis. Reverse transcription-polymerase chain reaction （RT-PCR） and Western blotting were performed to determine the mRNA and protein expressions of HSF1 and HSP70. Results The cure rate of the wounds and the total efficacy in the laser therapy group were significantly higher than those in the traditional therapy group （P 〈0.05, P 〈0.01, respectively）. Immunohistochemical staining revealed that the HSP70-positive cell count was significantly higher in laser therapy group than those in the traditional therapy group and controls （P 〈0.01）, and the gray scale of the cell signal was obviously lower than traditional therapy group and controls （P 〈0.05）. By contrast, the traditional therapy group and the control group were not significantly different. The RNA levels of HSF1 and HSP70 were higher in the laser therapy group by RT-PCR, but very low in normal skin and the traditional therapy group. The analysis on the gray scale of the Western blot bands indicated that the expression of HSF1 and HSP70 in the laser therapy group was significantly higher than in the traditional therapy group and the control group （P 〈0.01）, and the expression in the traditional therapy group was also higher than in the control group （P 〈0.05）. Conclusion Laser-aided therapy of chronic dermal ulcers plays a facilitating role in healing due to the mechanism of laser-activated endogenous heat shock protection in cells in wound surfaces.

Characterization of three transcripts encoding small heat shock proteins expressed in the codling moth, Cydia pomonella （Lepidoptera： Tortricidae）

Codling moth is a major pest of apples and pears worldwide. Increasing knowledge of how this insect responds to environmental stress will improve field and postharvest control measures used against it. The small heat shock proteins （sHsps） play a maj or role in cellular responses to environmental stressors. A degenerate oligonucleotide primer, designed against the conserved α-crystallin domain, was used in 3＇ rapid amplification of complementary DNA （cDNA） ends reactions to amplify transcripts encoding sHsps expressed in the codling moth cell line, Cp169, subjected to heat shock. Three full-length cDNAs were cloned from Cp169 cells that contained open reading frames encoding sHsps. The cDNA for CpHsp 19.8 was 795 bp encoding 177 amino acids. The cDNA for CpHsp 19.9 was 749 bp encoding 175 amino acids. The cDNA for CpHsp22.2 was 737 bp encoding 192 amino acids. Analysis of the protein sequences of the three CpHsps indicated the presence of 83 amino acids with homology to the α-crystallin domain. For each of the CpHsps, the α-crystallin domain was surrounded by divergent N- and C-terminal regions, consistent with the conserved structural features of sHsps. Real-time polymerase chain reaction, used to determine the expression patterns of each of the sHsps in different developmental stages of codling moth revealed the presence of transcripts in all stages tested. Consistent with characteristics of other sHsps, expression of CpHsp transcripts were greatly enhanced when insects were subjected to heat shock. The results of this research can be used as a guide to study the roles of sHsps in codling moth control using various post-harvest treatments.

Ribosome Profiling Reveals Genome-wide Cellular Translational Regulation upon Heat Stress in Escherichia coli

Heat shock response is a classical stress-induced regulatory system in bacteria, character- ized by extensive transcriptional reprogramming. To compare the impact of heat stress on the tran- scriptome and translatome in Escherich＆ coli, we conducted ribosome profiling in parallel with RNA-Seq to investigate the alterations in transcription and translation efficiency when E. coli cells were exposed to a mild heat stress （from 30 ~C to 45 ~C）. While general changes in ribosome foot- prints correlate with the changes of mRNA transcripts upon heat stress, a number of genes show differential changes at the transcription and translation levels. Translation efficiency of a few genes that are related to environment stimulus response is up-regulated, and in contrast, some genes func- tioning in mRNA translation and amino acid biosynthesis are down-regulated at the translation level in response to heat stress. Moreover, our ribosome occupancy data suggest that in generalribosomes accumulate remarkably in the starting regions of ORFs upon heat stress. This study pro- vides additional insights into bacterial gene expression in response to heat stress, and suggests the presence of stress-induced but yet-to-be characterized cellular regulatory mechanisms of gene expression at translation level.

Exercise Training for the Elderly:Inflammaging and the Central Role for HSP70

Inflammation is a common feature of aging tissues,being involved in most,if not all,age-related diseases.The origin of a low-grade inflammation state in aging(inflammaging)is multifactorial and may involve changes in body composition,immunosenescence,autophagy,microbiota modification and loss of proteostasis.The heat shock response pathway(HSR,and HSP70 expression)plays an important role as a mechanism of resolution of inflammation and proteostasis control.In this review,we sought to discuss the mechanisms that may lead to inflammaging,and the importance of the HSP70 in this process.Besides,we also discuss how physical exercise,particularly resistance training,can improve the HSR and the inflammatory balance of elderly people.