Induction Of Heat Shock Proteins Research Articles

Deletion of UCP1 in Tg2576 Mice Increases Body Temperature and Exacerbates Alzheimer's Disease-Related Pathologies.

We previously demonstrated that the Alzheimer's disease (AD)-like model mice, Tg2576, housed at a high ambient temperature of 30 °C for 13 months, exhibited increased body temperature, which increased amyloid-β (Aβ) levels and tau stability, leading to tau phosphorylation and ultimately inducing memory impairment. Here, we aimed to exclude the possible effect of environmental factors associated with the difference in ambient temperature (23 °C vs. 30 °C) and to further clarify the effects of elevated body temperature on AD-like pathologies. We generated uncoupling protein 1 (UCP1) deletion in Tg2576 mice, Tg2576/UCP1-/-, because UCP1 deletion mice show a sustained rise in body temperature at normal room temperature. As expected, the body temperature in Tg2576/UCP1-/- mice was higher than that in Tg2576/ UCP1+/+ mice at 23 °C, which was accompanied by upregulated Aβ levels due to increased β-secretase (BACE1) and decreased neprilysin (NEP) protein levels in the brains of Tg2576/UCP1-/- mice compared with those in the Tg2576/ UCP1+/+ mice. Elevated body temperature also increased total tau levels, leading to enhanced phosphorylation, heat shock protein induction, and activated tau kinases. Furthermore, elevated body temperature enhanced glial activation and decreased synaptic protein levels in the brain. Taken together, these findings demonstrate that elevated body temperatures exacerbate AD-like pathologies.

Polycomb response elements reduce leaky expression of Cas9 under temperature-inducible Hsp70Bb promoter in Drosophila melanogaster.

Heat-shock-inducible expression of genes through the use of heat-inducible promoters is commonly used in research despite leaky expression of downstream genes of interest without targeted induction (i.e. heat shock). The development of non-leaky inducible expression systems is of broad interest for both basic and applied studies, to precisely control gene expression. Here we characterize the use of Polycomb response elements and the inducible Heat-shock protein 70Bb promoter, previously described as a non-leaky inducible system, to regulate Cas9 endonuclease levels and function in Drosophila melanogaster after varying both heat-shock durations and rearing temperatures. We show that Polycomb response elements can significantly reduce expression of Cas9 under Heat-shock protein 70Bb promoter control using a range of conditions, corroborating previously published results. We further demonstrate that this low transcript level of heat-induced Cas9 is sufficient to induce mutant mosaic phenotypes. Incomplete suppression of an inducible Cas9 system by Polycomb response elements with no heat-shock suggests that further regulatory elements are required to precisely control Cas9 expression and abundance.

Pharmacological heat-shock protein inducers and chemical chaperones inhibit upregulation of interleukin-8 by oxidized phospholipids

Oxidised phospholipids such as oxidised palmitoyl-arachidonoyl-phosphatidylcholine (OxPAPC) are increasingly recognised as danger-associated molecular patterns (DAMPs) inducing cyto- and chemokines. The pathological impact of oxidised phosphatidylcholine in vivo has been demonstrated in several animal models, as well as in human association studies. In this work, we have tested a number of small molecules with known or potential anti-inflammatory properties for their ability to inhibit secretion of interleukin-8 by OxPAPC-treated endothelial cells. Six compounds capable of inhibiting the induction of IL-8 were selected. Analysis of gene expression has shown that all these substances reduced the OxPAPC-induced elevation of IL-8 mRNA but potentiated induction of heat-shock proteins (HSPs). We further found that drug-like HSP inducers also prevented the induction of IL-8 by OxPAPC. Similar inhibitory action was demonstrated by two chemical chaperones, which stabilise proteins through physicochemical mechanisms thus mimicking effects of HSPs. Our data suggest that proteostatic stress plays an important mechanistic role in the pro-inflammatory effects of OxPAPC and that stabilisation of proteome by overexpression of HSPs or by chemical chaperones can reduce the pro-inflammatory effects of OxPLs.

Glutamine supplementation attenuates intestinal apoptosis by inducing heat shock protein 70 in heatstroke rats.

Heatstroke is the most hazardous heat-related illness and has a high fatality rate. We investigated whether glutamine supplementation could have a protective effect on heatstroke rats. Twenty-five 12-week-old male Wistar rats (weight 305±16 g) were randomly divided into a control group (n=5), heatstroke (HS) group (n=10), and heatstroke+glutamine (HSG) group (n=10). Seven days before heat exposure, glutamine (0.4 g/[kg·d]) was administered to the rats in the HSG group by gavage every day. Three hours after heat exposure, serum samples were collected to detect white blood cells, coagulation indicators, blood biochemical indicators, and inflammatory cytokines in the rats. The small intestine tissue was stained to analyze pathological structural changes and apoptosis. Finally, immunohistochemistry and Western blotting were used to analyze the expression levels of heat shock protein 70 (HSP70). Multiple comparisons were analyzed by using one-way analysis of variance, and the Bonferroni test was conducted for the post hoc comparisons. After heat exposure, the core temperature of the HS group (40.65±0.31 °C) was higher than the criterion of heatstroke, whereas the core temperature of the HSG group (39.45±0.14 °C) was lower than the criterion. Glutamine supplementation restored the increased white blood cells, coagulation indicators, blood biochemical indicators, and inflammatory cytokines that were induced by heatstroke to normal levels. The intestinal mucosa was injured, and the structure of tight junctions was damaged in the HS group; however, the structure of intestinal mucosal epithelial cells was stable in the HSG group. Glutamine supplementation alleviated intestinal apoptosis and up-regulated HSP70 expression. Glutamine supplementation may alleviate intestinal apoptosis by inducing the expression of HSP70 and have a protective effect on heatstroke rats.

Role of Heat Shock Proteins in Atrial Fibrillation: From Molecular Mechanisms to Diagnostic and Therapeutic Opportunities

Heat shock proteins (HSPs) are endogenous protective proteins and biomarkers of cell stress response, of which examples are HSP70, HSP60, HSP90, and small HSPs (HSPB). HSPs protect cells and organs, especially the cardiovascular system, against harmful and cytotoxic conditions. More recent attention has focused on the roles of HSPs in the irreversible remodeling of atrial fibrillation (AF), which is the most common arrhythmia in clinical practice and a significant contributor to mortality. In this review, we investigated the relationship between HSPs and atrial remodeling mechanisms in AF. PubMed was searched for studies using the terms "Heat Shock Proteins" and "Atrial Fibrillation" and their relevant abbreviations up to 10 July 2022. The results showed that HSPs have cytoprotective roles in atrial cardiomyocytes during AF by promoting reverse electrical and structural remodeling. Heat shock response (HSR) exhaustion, followed by low levels of HSPs, causes proteostasis derailment in cardiomyocytes, which is the basis of AF. Furthermore, potential implications of HSPs in the management of AF are discussed in detail. HSPs represent reliable biomarkers for predicting and staging AF. HSP inducers may serve as novel therapeutic modalities in postoperative AF. HSP induction, either by geranylgeranylacetone (GGA) or by other compounds presently in development, may therefore be an interesting new approach for upstream therapy for AF, a strategy that aims to prevent AF whilst minimizing the ventricular proarrhythmic risks of traditional anti-arrhythmic agents.

Native Size-Exclusion Chromatography–Based Mass Spectrometry Reveals New Components of the Early Heat Shock Protein 90 Inhibition Response Among Limited Global Changes

The molecular chaperone heat shock protein 90 (HSP90) works in concert with co-chaperones to stabilize its client proteins, which include multiple drivers of oncogenesis and malignant progression. Pharmacologic inhibitors of HSP90 have been observed to exert a wide range of effects on the proteome, including depletion of client proteins, induction of heat shock proteins, dissociation of co-chaperones from HSP90, disruption of client protein signaling networks, and recruitment of the protein ubiquitylation and degradation machinery—suggesting widespread remodeling of cellular protein complexes. However, proteomics studies to date have focused on inhibitor-induced changes in total protein levels, often overlooking protein complex alterations. Here, we use size-exclusion chromatography in combination with mass spectrometry (SEC-MS) to characterize the early changes in native protein complexes following treatment with the HSP90 inhibitor tanespimycin (17-AAG) for 8 h in the HT29 colon adenocarcinoma cell line. After confirming the signature cellular response to HSP90 inhibition (e.g., induction of heat shock proteins, decreased total levels of client proteins), we were surprised to find only modest perturbations to the global distribution of protein elution profiles in inhibitor-treated HT29 cells at this relatively early time-point. Similarly, co-chaperones that co-eluted with HSP90 displayed no clear difference between control and treated conditions. However, two distinct analysis strategies identified multiple inhibitor-induced changes, including known and unknown components of the HSP90-dependent proteome. We validate two of these—the actin-binding protein Anillin and the mitochondrial isocitrate dehydrogenase 3 complex—as novel HSP90 inhibitor-modulated proteins. We present this dataset as a resource for the HSP90, proteostasis, and cancer communities (https://www.bioinformatics.babraham.ac.uk/shiny/HSP90/SEC-MS/), laying the groundwork for future mechanistic and therapeutic studies related to HSP90 pharmacology. Data are available via ProteomeXchange with identifier PXD033459.

Onset of Adverse Abdominal Events Due to Intestinal Ischemia-Reperfusion Injury after Aortic Cross-Clamping Is Associated with Elevated HSP70 Serum Levels in the Early Postoperative Phase

Tissue injury of the viscera during open thoracoabdominal aortic (TAA) reconstructions has been reported as the aftermath of the ischemia-reperfusion mechanism following supracoeliac aortic cross-clamping. Abdominal complications after open aortic reconstructions, although rare through the intraoperative implementation of selective visceral artery blood perfusion, are associated with high rates of reinterventions and a poor prognosis. Recent animal experiments demonstrated that provoking mesenteric ischemia in rats induces the leukocyte-mediated transcription of heat-shock protein 70 (HSP70), a chaperone belonging to the danger-associated molecular pattern proteins (DAMPs). Translating these findings clinically, we investigated the serum levels of HSP70 in patients undergoing open aortic reconstructions with supracoeliac clamping. We postoperatively observed a relevant induction of HSP70, which remained significantly elevated in cases of postoperative abdominal complications (paralytic ileus, abdominal compartment syndrome, and visceral malperfusion). The receiver-operator curve analysis revealed the reliable prognostic accuracy of HSP70 as a biomarker for these complications as soon as 12 h post-operation (AUC 0.908, sensitivity 88.9%, specificity 83.3%). In conclusion, measuring HSP70 serum levels in the early postoperative phase may serve as a further adjutant in the diagnostic decision making for both the vascular surgeon and intensivist for the timely detection and management of abdominal complications following open TAA surgery.

Uptake of Flaxseed Dietary Linusorbs Modulates Regulatory Genes Including Induction of Heat Shock Proteins and Apoptosis.

Flaxseed (Linum usitatissimum L.) is gaining popularity as a superfood due to its health-promoting properties. Mature flax grain includes an array of biologically active cyclic peptides or linusorbs (LOs, also known as cyclolinopeptides) that are synthesized from three or more ribosome-derived precursors. Two flaxseed orbitides, [1-9-NαC]-linusorb B3 and [1-9-NαC]-linusorb B2, suppress immunity, induce apoptosis in a cell line derived from human epithelial cancer cells (Calu-3), and inhibit T-cell proliferation, but the mechanism of LO action is unknown. LO-induced changes in gene expression in both nematode cultures and human cancer cell lines indicate that LOs promoted apoptosis. Specific evidence of LO bioactivity included: (1) distribution of LOs throughout the organism after flaxseed consumption; (2) induction of heat shock protein (HSP) 70A, an indicator of stress; (3) induction of apoptosis in Calu-3 cells; and (4) modulation of regulatory genes (determined by microarray analysis). In specific cancer cells, LOs induced apoptosis as well as HSPs in nematodes. The uptake of LOs from dietary sources indicates that these compounds might be suitable as delivery platforms for a variety of biologically active molecules for cancer therapy.

Inhibition of Heat Shock Factor 1 Signaling Decreases Hepatoblastoma Growth via Induction of Apoptosis

Although rare compared with adult liver cancers, hepatoblastoma (HB) is the most common pediatric liver malignancy, and its incidence is increasing. Currently, the treatment includes surgical resection with or without chemotherapy, and in severe cases, liver transplantation in children. The effort to develop more targeted, HB-specific therapies has been stymied by the lack of fundamental knowledge about HB biology. Heat shock factor 1 (HSF1), a transcription factor, is a canonical inducer of heat shock proteins, which act as chaperone proteins to prevent or undo protein misfolding. Recent work has shown a role for HSF1 in cancer beyond the canonical heat shock response. The current study found increased HSF1 signaling in HB versus normal liver. It showed that less differentiated, more embryonic tumors had higher levels of HSF1 than more differentiated, more fetal-appearing tumors. Most strikingly, HSF1 expression levels correlated with mortality. This study used a mouse model of HB to test the effect of inhibiting HSF1 early in tumor development on cancer growth. HSF1 inhibition resulted in fewer and smaller tumors, suggesting HSF1 is needed for aggressive tumor growth. Moreover, HSF1 inhibition also increased apoptosis in tumor foci. These data suggest that HSF1 may be a viable pharmacologic target for HB treatment.

Dietary Tenebrio molitor Larvae Meal Inclusion Exerts Tissue-Specific Effects on Cellular, Metabolic, and Antioxidant Status in European Sea Bass (Dicentrarchus labrax) and Gilthead Seabream (Sparus aurata).

The present study addresses the effects of dietary Tenebrio molitor (TM) larvae meal inclusion on cytoprotective, cell death pathways, antioxidant defence, and intermediate metabolism in the heart, muscle, and digestive tract of gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax). Three experimental diets were formulated to contain 0%, 25%, or 50% inclusion TM levels. Heat Shock Proteins (HSPs) induction was apparent in both species' muscle at 50% inclusion. Conversely, p44/42 Mitogen-Activated Protein Kinase (MAPK) activation was increased (p < 0.05) in both species' muscle and digestive tract at 25% inclusion. Regarding the apoptotic machinery, TM inclusion exerted no influence on gilthead seabream, while suppression through autophagy may have occurred in the muscle. However, significant apoptosis (p < 0.05) was evident in European sea bass muscle and digestive tract. Both fish species' heart seemed to additionally rely on lipids compared to muscle and digestive tract. In contrast to gilthead seabream, European sea bass exhibited increased (p < 0.05) antioxidant activity at 50% TM inclusion. The present findings highlight the dietary derived induction of cellular responses in a species- and tissue-specific manner, whereas European sea bass appears to be more susceptible to TM inclusion.

Role of HSP and Leptin in Dairy Animals during Thermal Stress: A Review

Thermal stress is a unique and complex process which alters the normal physiological mechanisms. Heat shock proteins (HSPs) are known to be highly conserved and ubiquitous proteins synthesized in response to several stimuli. The HSP inducers have been categorized as environmental (heat shock, UV radiation, heavy metals, amino acids, oxidative stress, etc.) pathological (bacterial or parasitic infections, fever, inflammation, etc.) and physiological (growth factors, cell differentiation, hormonal stimulation or tissue development, caloric restriction, etc.). The HSPs play an important role for maintaining cellular functioning under environmental challenges and protein denaturation conditions. There is a great potential for using HSP72 expression to detect natural adaptation and exposure to stress in natural populations. Leptin is a 16 kDa polypeptide hormone secreted primarily from the cells of white adipose tissue. Leptin acts through both central and peripheral mechanisms to affect feeding behaviour, lipid and glucose metabolism, thermogenesis, reproductive and endocrine functions. Leptin also plays an important role in the regulation of body weight and composition, e.g. reduction in feed intake and increase in energy expenditure. Bovine lymphocytes express Ob-Rb gene (leptin receptor) and also express leptin. There are ample information on the central role of leptin in brain and neural tissue regulation. In dairy cattle, the increase in milk yield has been associated with a negative energy balance and a decrease in fertility during early lactation. The hormone leptin is involved in regulation of nutritional status and reproductive function.

Carbohydrate Metabolism in Diabetic Rat’s Heart – The Effects of Acetylsalicylic Acid and Heat Preconditioning as HSP70 Inducers

Abstract The myocardium of diabetic subjects displays reduced HSP70 protein level and weak myocardial protection. However, the heart possesses an ability to produce heat shock proteins (HSPs) after exposure to sublethal heat stress. Acetylsalicylicacid (ASA) has the property of pharmacological induction of HSPs. We evaluated the common effects of single dose ASA-pretreatment, prior to heat preconditioning (HP), over carbohydrate metabolism-related enzymes and substrates in the heart of diabetic rats. Streptozotocin-diabetes caused significant decrease of HSP70 protein level, stimulation of the gluconeogenic processes and inhibition of glycolytic processes in the heart. HP-diabetic hearts have significantly higher HSP70 protein level, lower glycogen, glucose-6-phosphate content, glycogen phosphorylase and hexokinase activity, and higher glucose levels and PFK activity. ASA-pretreatment of HP-diabetic animals caused additional increase of HSP70, additional decrease of glycogen, glucose-6-phosphate, glycogen phosphorylase and hexokinase, and additional increase of glucose and PFK in the heart. In conclusion, HP is physiological inducer of HSP70 level in heart and tends to reverse carbohydrate - related disturbances in diabetic rats. ASA, given prior to HP, is a potent HSP70 co-inducer and causes additional increase of HSP70 protein level in heart. ASA, given in a combination to HP, have shown more evident protective effects against subsequent intense of stress.

Synergistic effect of standardized extract of Asparagus officinalis stem and heat shock on progesterone synthesis with lipid droplets and mitochondrial function in bovine granulosa cells

Progesterone (P4) is a well-known steroid hormone that plays a key role in oocyte growth and the maintenance of pregnancy in mammals, including cattle. Heat stress (HS) has an adverse effect on P4 synthesis through an imbalance in the cellular redox status. We have recently revealed that a standardized extract of Asparagus officinalis stem (EAS) increases P4 through non-HS induction of heat shock protein 70 (HSP70) and a synergistic increase of HSP70 by enhancing the intracellular redox balance, which was adversely affected by HS in bovine granulosa cells (GCs). Bovine GCs collected from bovine ovarian follicles were cultured at 38.5 °C and 41 °C for 12 h with or without 5 mg/mL EAS. After treatment, cells and culture suppernatant were collected for the analysis. Enzyme-linked immunosorbent assay (ELISA) was performed to detect in P4 levels. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) was used to detect expression of steroidogenesis related genes. Fluorescence staining was used to detect mitochondrial activity and lipid droplet. P4 level was increased by EAS treatment in association with increase in steroidogenic acute regulatory protein (STAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), mitochondrial membrane activity and lipid droplet both under non-HS and HS conditions. Notably, synergistic effect of EAS with HS co-treatment was observed to show a greater increase in P4 synthesis when comparison with EAS treatment under non-HS condition. Furthermore, inhibition of HSP70 significantly reduced EAS-induced P4 synthesis, mitochondrial activity and synthesis of lipid droplets. These results suggest that P4 synthesis by EAS is mediated by the steroidogenesis pathway via HSP70-regulated activation of STAR and 3β-HSD, together with improved mitochondrial activity and lipid metabolism in bovine GCs. Moreover, effect of EAS has a synergistic effect of with HSP70-regulated steroidogenesis pathway.

Low Concentrations of Oxidized Phospholipids Increase Stress Tolerance of Endothelial Cells.

Oxidized phospholipids (OxPLs) are generated by enzymatic or autooxidation of esterified polyunsaturated fatty acids (PUFAs) residues. OxPLs are present in circulation and atherosclerotic plaques where they are thought to induce predominantly proinflammatory and toxic changes in endothelial (ECs) and other cell types. Unexpectedly, we found that low concentrations of OxPLs were not toxic but protected ECs from stress induced by serum deprivation or cytostatic drugs. The protective effect was observed in ECs obtained from different vessels and was monitored using a variety of readouts based on different biological and chemical principles. Analysis of the structure–activity relationship identified oxidized or missing fatty acid residue (OxPLs or Lyso-PLs, respectively) as a prerequisite for the protective action of a PL. Protective OxPLs or Lyso-PLs acquired detergent-like properties and formed in solution aggregates <10 nm in diameter (likely micelles), which were in striking contrast with large aggregates (>1000 nm, likely multilayer liposomes) produced by nonoxidized precursor PLs. Because surfactants, OxPLs, and Lyso-PLs are known to extract membrane cholesterol, we tested if this effect might trigger the protection of endothelial cells. The protective action of OxPLs and Lyso-PLs was inhibited by cotreatment with cholesterol and mimicked by cholesterol-binding beta-cyclodextrin but not inactive α-cyclodextrin. Wide-scale mRNA expression analysis in four types of ECs showed the induction of genes encoding for heat shock proteins (HSPs) and secreted prosurvival peptides and proteins. Inducers of HSPs, chemical chaperones, and pure prosurvival factors mimicked the protective action of OxPLs/Lyso-PLs. We hypothesize that oxidation changes the physicochemical properties of PLs, thus promoting membrane cholesterol redistribution or extraction leading to the expression of intra- and extracellular prosurvival factors.

Induction of stress defense response and quality retention in minimally processed peaches through the application of gamma irradiation treatments

Consumers demand fruit and vegetable products "on the go" that maintain color, flavor, nutritional and bioactive compounds almost equal to fresh products. Irradiation represents an effective technology traditionally used in fruit and vegetable as a phytosanitary treatment to preserve food quality and safety. In the present study we evaluated the effect of gamma irradiation treatments at several doses (0, 0.1, 0.3, 1.0, 2.5 kGy) on the quality and biochemical aspects of minimally processed peaches (Prunus persica L. Batsch) with low oxygen permeability packaging. During minimal processing, peach slices were treated in an antioxidant solution containing 1 % ascorbic acid and 0.5 % citric acid for 2 min. Trays of minimally processed peaches were irradiated packed inside cardboard boxes. Changes in color, firmness and polyphenoloxidase (PPO) and peroxidase (POD) activities of peaches were analyzed at different storage times (0, 7, 14 d) at 4 °C. In addition, the stress response of plant to these treatments was assessed by using the induction of heat shock proteins (HSP) as a biochemical marker. Results show that irradiation caused no substantial changes in chromatic parameters, although an immediate reduction in firmness and POD activity was observed, proportional to the increased doses applied. In turn, PPO activity remained stable while the activity of some of its isoenzymes decreased for doses higher than 0.3 kGy. The overexpression of HSP, only detected for irradiation doses of 0.1 and 0.3 kGy, in coincidence with the best performing treatments, constitutes a relevant finding not previously reported in fruit. Therefore, low doses of irradiation promoted the physiological and biochemical defense mechanisms of the fruit. HSP could thus be used in plant tissues as a biomarker of the stress brought about by exposure to irradiation, capable of preventing physiological damage. These preliminary results suggest that irradiation treatments (up to 1.0 kGy) in combination with modified atmosphere packaging (from 19 % and 10 % O2 at 0 d to 3 % and 15 % CO2 at 14 d of storage) could render high quality peach products with an extended shelf life.

Induced heat shock protein 70 confers biological tolerance in UV-B stress–adapted Myzus persicae (Hemiptera)

As an environmental stress factor, ultraviolet-B (UV-B) radiation directly affects insect growth, development, and reproduction. Heat shock protein 70s kDa (Hsp70s) plays an important role in the environmental adaptation of insects. To determine the role of MpHsp70s in the UV-B tolerance of Myzus persicae (Sulzer), we identified the complete complementary DNA sequences of seven MpHsp70s. They were found to be ubiquitously expressed during different developmental stages and were highly expressed in second-instar nymphs and wingless adults. The expression levels of the MpHsp70s were significantly upregulated when exposed to different durations of UV-B stress. Nanocarrier-mediated dsMpHsp70 suppressed the expression of the MpHsp70s and reduced the body length, weight, survival rate, and fecundity of M. persicae under UV-B exposure. When the combinational RNAi approach was adopted, the effects on the survival rate and fecundity were greater under UV-B stress, except for MpHsc70-4. These results suggest that MpHsp70s are essential for the resistance of M. persicae to UV-B stress.

HSP70 upregulation in nasal mucosa of symptomatic children with allergic rhinitis and potential risk of asthma development

Allergic rhinitis and asthma are the most common causes of chronic inflammation of the upper and lower airways in childhood. However, a nasal biomarker that can link to pulmonary inflammation is yet to be found. The present paper aims to investigate the possible role in inflammation of two inducible 70-kDa Heat Shock Proteins (HSP70) members, HSPA1A/B and HSPA6, in nasal mucosa cells of allergic children through their mRNA expression analysis, and their correlation to both spirometric and FeNO values. The relationship between FeNO in lower airways and ∆Cts of HSPA1A/B in nasal mucosa seems to be influenced by clinical symptoms regardless of age, sex, and sensitization patterns. Therefore, HSP70 expression, as well as FeNO levels, could have a predictive capability to identify lower airways inflammation and thus to recognize rhinitic children having a potential risk of asthma development.

Loss of heat shock factor 1 promotes hepatic stellate cell activation and drives liver fibrosis.

Liver fibrosis is an aberrant wound healing response that results from chronic injury and is mediated by hepatocellular death and activation of hepatic stellate cells (HSCs). While induction of oxidative stress is well established in fibrotic livers, there is limited information on stress‐mediated mechanisms of HSC activation. Cellular stress triggers an adaptive defense mechanism via master protein homeostasis regulator, heat shock factor 1 (HSF1), which induces heat shock proteins to respond to proteotoxic stress. Although the importance of HSF1 in restoring cellular homeostasis is well‐established, its potential role in liver fibrosis is unknown. Here, we show that HSF1 messenger RNA is induced in human cirrhotic and murine fibrotic livers. Hepatocytes exhibit nuclear HSF1, whereas stellate cells expressing alpha smooth muscle actin do not express nuclear HSF1 in human cirrhosis. Interestingly, despite nuclear HSF1, murine fibrotic livers did not show induction of HSF1 DNA binding activity compared with controls. HSF1‐deficient mice exhibit augmented HSC activation and fibrosis despite limited pro‐inflammatory cytokine response and display delayed fibrosis resolution. Stellate cell and hepatocyte‐specific HSF1 knockout mice exhibit higher induction of profibrogenic response, suggesting an important role for HSF1 in HSC activation and fibrosis. Stable expression of dominant negative HSF1 promotes fibrogenic activation of HSCs. Overactivation of HSF1 decreased phosphorylation of JNK and prevented HSC activation, supporting a protective role for HSF1. Our findings identify an unconventional role for HSF1 in liver fibrosis. Conclusion: Our results show that deficiency of HSF1 is associated with exacerbated HSC activation promoting liver fibrosis, whereas activation of HSF1 prevents profibrogenic HSC activation.

Overexpression of Heat Shock Protein 70 Ameliorates Meat Quality of Broilers Subjected to Pre-Slaughter Transport at High Ambient Temperatures by Improving Energy Status of Pectoralis Major Muscle and Antioxidant Capacity.

The induction of heat shock protein 70 (HSP70) potentially mediates meat-quality development under stress conditions. To investigate the effects and mechanism of HSP70 on the meat quality of the pectoralis major (PM) muscles of broilers exposed to pre-slaughter transport, a total of 168 broilers were intraperitoneally injected with L-glutamine (Gln) or saline. Twenty-four hours later, broilers were subjected to transport or held under normal living conditions. The results indicated that acute Gln supplementation significantly increased HSP70 expression in the PM of transported broilers (p < 0.05). The overexpression of HSP70 significantly alleviated the decreases in muscle pH and water-holding capacity and improved the shrinking of muscle fibers induced by transport (p < 0.05). HSP70 induction increased ATP content, decreased the activities of glycolytic enzymes, and lowered the phosphorylation level of AMP-activated protein kinase in transported broilers (p < 0.05). In addition, the overexpression of HSP70 greatly increased total superoxide dismutase and the total antioxidant capability and decreased the levels of reactive oxygen species, malonaldehyde, and carbonyls in the PM of transported broilers (p < 0.05). Overall, this work indicated that HSP70 could effectively improve the meat quality of transported broilers by improving the energy status, inhibiting glycolytic influx, and restoring redox homeostasis.

Inducible Heat Shock Protein 70 Levels in Patients and the mdx Mouse Affirm Regulation during Skeletal Muscle Regeneration in Muscular Dystrophy.

Stress-inducible heat shock protein 70 (HSP70) is both a protective chaperone involved in protein homeostasis and an immune regulator. In both capacities, HSP70 has been implicated in muscle disorders, yet with fragmented and differing results. In this study we aimed to compare results obtained in the mouse model for the severest form of muscular dystrophy (MD) equivalent to Duchenne MD, termed the mdx mouse, with results obtained in human MD. Skeletal muscle and serum samples were obtained from 11 healthy controls, 11 fully characterized patients diagnosed with Becker MD and limb girdle MD (LGMD), and six muscle disease controls. In addition, muscle extracts were prepared from tibialis anterior of mdx and control mice at ages 4, 8 and 12 weeks. The HSP70 levels were quantified using RT-PCR, western blotting and protein arrays, and localized in muscle tissue sections using double immunofluorescence. We found selective and significant 2.2-fold upregulation of HSP70 protein in mdx tibialis muscle at the earliest disease phase only. In LGMD and Becker MD patients, HSP70 protein levels were not significantly different from those of healthy muscle and serum. HSP70 was localized to regenerating muscle fibers both in mouse and human MD skeletal muscle tissues. Toll-like receptor (TLR) 2 and TLR4 expression was moderately increased on the sarcolemma in MD muscle, yet protein levels were not significantly different from normal controls. HSP70 upregulation in MD appears disease stage-dependent, marking the phase of most active muscle regeneration in the mdx mouse. We postulate that well-timed supportive therapeutic interventions with HSP70 agonists could potentially improve muscle tissue's regenerative capacities in MD, attenuating loss of muscle mass while we await gene therapies to become more widely available.