Increase In Hsp70 Research Articles

Alleviation of cold stress induced oxidative stress in White Leghorn Chicken by Chromium and Vitamin C supplementation

White Leghorn layer chicken experienced cold stress during December, 2019 to January, 2020 with lowestminimum AT and lowest average temperature during later part of January, 2020. Cold stress caused increasein HSP70 and SOD of White Leghorn layer chicken. Supplementation of chromium picolinate (@ 400 μg/kgfeed) and vitamin C (@ 250 mg/kg of feed) alleviated cold stress and cold induced oxidative stress in White Leghornchicken. Alleviation of stress by supplementation of chromium picolinate and vitamin C could be estimated bythe measure of drop in HSP70 and SOD. Supplementation of chromium picolinate and vitamin C also had beneficialimpacts on egg length during cold stress. Combination of chromium picolinate and vitamin C was best to alleviatecold stress while vitamin C was best to lower oxidative stress in layer.

Astaxanthin supplementation impacts the cellular HSP expression profile during passive heating.

Astaxanthin is a powerful carotenoid antioxidant prevalent in marine organisms and approved as a food supplement. Recent studies have demonstrated Astaxanthin's beneficial attributes in various health states. Following initial reports of potential heat protective properties in Astaxanthin supplemented rats, we present here results of a novel study examining the effect of Astaxanthin supplementation on the heat shock response in rats in relation to core temperature (Tc) and the ensuing physiological strain. Two hours of heat stress at 41°C during which rats developed their thermoregulatory hyperthermic plateau resulted in progressive increases in HSP72 and HSP27 in the Astaxanthin (Oleoresin)-treated group but not in the control (Olive oil) group. Enhanced elevation in HSPs suggests that Astaxanthin supplementation may augment the cellular stress protective response to heat stress.

Hsp72 and Hsp90α mRNA transcription is characterised by large, sustained changes in core temperature during heat acclimation.

Increased intracellular heat shock protein-72 (Hsp72) and heat shock protein-90α (Hsp90α) have been implicated as important components of acquired thermotolerance, providing cytoprotection during stress. This experiment determined the physiological responses characterising increases in Hsp72 and Hsp90α mRNA on the first and tenth day of 90-min heat acclimation (in 40.2°C, 41.0% relative humidity (RH)) or equivalent normothermic training (in 20°C, 29% RH). Pearson's product-moment correlation and stepwise multiple regression were performed to determine relationships between physiological [e.g. (Trec, sweat rate (SR) and heart rate (HR)] and training variables (exercise duration, exercise intensity, work done), and the leukocyte Hsp72 and Hsp90α mRNA responses via reverse transcription quantitative polymerase chain reaction (RT-QPCR) (n=15). Significant (p<0.05) correlations existed between increased Hsp72 and Hsp90α mRNA (r=0.879). Increased core temperature was the most important criteria for gene transcription with ΔTrec (r=0.714), SR (r=0.709), Trecfinal45 (r=0.682), area under the curve where Trec≥38.5°C (AUC38.5°C; r=0.678), peak Trec (r=0.661), duration Trec≥38.5°C (r=0.650) and ΔHR (r=0.511) each demonstrating a significant (p<0.05) correlation with the increase in Hsp72 mRNA. The Trec AUC38.5°C (r=0.729), ΔTrec (r=0.691), peak Trec (r=0.680), Trecfinal45 (r=0.678), SR (r=0.660), duration Trec≥38.5°C (r=0.629), the rate of change in Trec (r=0.600) and ΔHR (r=0.531) were the strongest correlate with the increase in Hsp90α mRNA. Multiple regression improved the model for Hsp90α mRNA only, when Trec AUC38.5°C and SR were combined. Training variables showed insignificant (p>0.05) weak (r<0.300) relationships with Hsp72 and Hsp90α mRNA. Hsp72 and Hsp90α mRNA correlates were comparable on the first and tenth day. When transcription of the related Hsp72 and Hsp90α mRNA is important, protocols should rapidly induce large, prolonged changes in core temperature.

Heat Shock Factor Activation in Skeletal Muscle Following Lengthening Contractions

Heat shock proteins (HSPs) are integral for the maintenance of proteostasis and allowing cells to cope with episodes of stress. HSPs are regulated by transcription factors known as heat shock transcription factors (HSFs). Given that when skeletal muscles are subjected to lengthening contractions (LCs) both muscle damage and HSPs are increased, it was of interest to investigate the mechanism of the LC‐induced increase in HSPs and assess the role of HSFs in this process. Thus, the purpose of this study was to determine if HSF activation (HSF trimerization and DNA binding) is elevated in rat skeletal muscle following exposure to 60 LCs. To do this, male sprague‐dawley rats were anaesthetized and one tibialis anterior (TA) muscle was subjected to 60 LCs (3 sets of 20 LCs with 5 minutes rest between sets) and removed at 0, 1, 3, or 24 hours after LCs, while the non‐stimulated contralateral TA served as a control. Hsp72 and Hsp25 content, HSF activation, muscle damage, and muscle glycogen content were assessed at various time points. Following 60 LCs, electrophoretic shift assay showed a transient increase in HSF activation (0–3 hours) that was followed by a significant (p&lt;0.001) increase in Hsp72 (3.4±0.21 fold) and Hsp25 (3.2±1.2 fold) content 24 hours later as assessed by western blotting. Histological assessment of the TA muscle revealed evidence of muscle damage (measured as necrotic fibers and inflammatory infiltrates) and glycogen depletion. Taken together, the results suggest LCs induce structural and metabolic stress that results in muscle damage, increased HSF activation and the accumulation of Hsp72 and Hsp25.Support or Funding InformationNo external funding

Cardiac molecular markers of programmed cell death are activated in end-stage heart failure patients supported by left ventricular assist device.

Cardiomyocyte apoptosis increases in heart failure (HF) and is implicated in disease progression. The apoptotic cell is not inevitably committed to death, and appropriate therapy like left ventricular assist device (LVAD) support could offer a rescue of cellular functions. Literature data regarding the modulation of the apoptotic process during LVAD support are still controversial. To assess whether LVAD implantation modifies the apoptotic profile in the heart, cardiac tissue was collected from end-stage HF patients before LVAD implant (pre-LVAD, n=22) and at LVAD removal (post-LVAD, n=6) and from stable HF patients on medical therapy without prior circulatory support (HTx, n=7) at heart transplantation as control. Caspase (Casp)-3, Bax, Bcl-2, and Hsp72 cardiac mRNA and protein expression were evaluated by real-time polymerase chain reaction and Western blotting (WB) in the three groups of patients. Immunohistochemical analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, and DNA laddering analysis were performed; cellular size and interstitial fibrosis content were also determined. All the apoptotic indices were increased in the post-LVAD group compared to pre-LVAD, specially antiapoptotic Hsp72 and proapoptotic Bax (Hsp72: 3.27±0.41 vs. 0.76±0.14, P<.001; Bax: 2.15±0.38 vs. 1.10 ± 0.29, P=.035; post-LVAD vs. pre-LVAD, respectively). The significant increase in Hsp72 was confirmed by WB and immunohistochemical analysis. LVAD appears to induce an activation of apoptotic mediators, mainly at the mitochondrial level, while the following activation of Casp-3 is reduced by the significant increase of Hsp72, whose enhancement could be an important factor in cardiac remodeling associated with LVAD support.

Modulation of stress related protein genes in the bass (Epinephelus guaza) caught from the Gulf of Suez, the Red Sea, Egypt

Impact of chemical pollution on expression of stress protein genes in the bass Epinephelus guaga collected from several locations including Suez Oil Production Port (Floating port), Atakah Fishing Port, Adabiya Port and Tawfik Port in Suez Governorate, Egypt, was investigated. In the current study, levels of polycyclic aromatic hydrocarbons (PAHs) in water and fish samples collected from Suez Gulf were assessed. In addition, gills and liver tissues of caught bass fish were used to address the interaction between pollution status and the expression of stress-related genes (Hsp70a, Hsp70b, Hsp47, MT and CYP1A). Our analysis demonstrated that levels of PAHs in Floating and Tawfik ports were higher than those found in the Atakah Fishing Port and the Adabiya Port. In addition, MDA and PC contents were significantly higher in gills and liver tissues collected from Floating and Tawfik ports than those collected from Adabiya and Atakah ports. In correlation to the above results, all fish collected from the Floating and Tawfik ports presented a significant increase in Hsp-, MT- and CYP1A—mRNAs. On the other hand, fish samples collected from the Atakah Fishing and Adabiya ports showed no induction of the stress-related genes transcription in such tissues. In conclusion, the current research demonstrates that remarkable increase in PAH contaminants levels in Floating and Tawfik ports are correlated with the levels stress protein-related genes transcription in E. guaga gills and liver tissues.

Realgar bioleaching solution suppress ras excessive activation by increasing ROS in Caenorhabditis elegans

Although realgar bioleaching solution (RBS) has been proved to be a potential candidate for cancer therapy, the mechanisms of RBS anticancer are still far from being completely understood. Dosed with RBS in C. elegans, the multivulva phenotype resulting from oncogenic ras gain-of-function was inhibited in a dose dependent manner. It could be abrogated by concurrent treatment C. elegans with RBS and the radical scavenger DMSO. However, RBS could not induce DAF-16 nuclear translocation in TJ356 or the increase of HSP 16.2 expression in CL2070, which both could be aroused visible GFP fluorescent variation to represent for oxidative stress generation. Treatment C. elegans with superoxide anion generator paraquat, similar results were also obtained. Our results indicated that RBS suppress excessive activated ras by increasing reactive oxygen species (ROS) in C. elegans. Secondly, ROS induced by RBS significantly accumulated on a higher level in C. elegans with a mutational ras than that with wild ras, thus leading to oxidative stress on ras gain-of-function background rather than on normal ras context. Our results firstly demonstrated that using C. elegans as a model organism for evaluating prooxidant drug candidates for cancer therapy.

Physical Exercise Induces Excess Hsp72 Expression and Delays the Development of Hyperalgesia and Allodynia in Painful Diabetic Neuropathy Rats

The underlying mechanism of exercise on the development of diabetes-associated neuropathic pain is not well understood. We investigated in rats whether exercise regulates the functional recovery and heat shock protein 72 (Hsp72), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 expression in streptozotocin (STZ)-induced diabetes. Male Wistar rats were divided into 4 groups: normal sedentary rats, normal rats with exercise, sedentary STZ-diabetic (SS) rats, and STZ-diabetic rats with exercise. Diabetes was induced with STZ (65 mg/kg IV). The trained rats ran daily on a treadmill 30 to 60 min/d with an intensity of 20 to 25 m/min. We monitored thermal withdrawal latency and mechanical withdrawal threshold as well as Hsp72, TNF-α, and IL-6 expression in the spinal cord and peripheral nerves. Two weeks after STZ injection, sedentary rats exhibited a marked and sustained hypersensitivity to von Frey tactile and heat stimuli. In contrast, diabetic rats undergoing exercise demonstrated delayed progress of tactile and thermal hypersensitivity. Exercise significantly suppressed diabetes-induced blood glucose levels and body weight loss, although they were not restored to control levels. Compared with normal sedentary rats, SS rats displayed significantly higher TNF-α and IL-6 levels in the spinal cord and peripheral nerves. The STZ-diabetic rats with exercise group showed greater Hsp72 expression and similar TNF-α or IL-6 level compared with the SS group in the spinal cord and peripheral nerves on day 14 after STZ treatment. These results suggest that progressive exercise training markedly decreases diabetes-associated neuropathic pain, including thermal hyperalgesia and mechanical allodynia. In rats, this protective effect is related to the increase of Hsp72, but not TNF-α and IL-6, expression in the spinal cord and peripheral nerves of STZ-induced diabetes.

Effect of Treadmill Exercise and Ferula gummosa on Myocardial HSP72, Vascular Function, and Antioxidant Defenses in Spontaneously Hypertensive Rats

This study evaluates the effect of treadmill exercise and Ferula gummosa (FG) on heat shock protein (HSP72), biomarkers related to vascular function, and oxidant/antioxidant system in the heart tissue of spontaneously hypertensive rats treated with N(ω)-nitro-l–arginine-methyl ester (l–NAME). Fifty adult male Wistar rats are randomly classified into five groups: treadmill exercise, FG, combination of treadmill exercise + FG, l–NAME, and saline. Treadmill exercise was performed between 25 and 64 minutes at the speed of 15–22 m per minute for 8 weeks and five sessions a week. The FG will be fed through gavage with 90 mg/kg dosage. Hypertension was induced by l–NAME (10 mg/kg) for 8 weeks and six sessions a week. Administration of l–NAME for 8 weeks caused significant increase in HSP72, angiotensin-converting enzyme (ACE), and protein carbonyl (PC), and significant decrease in glutathione peroxidase (GPx) and nitric oxide (NO) level, when compared with the saline group. In contrast, both treadmill exercise and/or FG protocols, in particular, the combined protocol, led to the improvement in HSP72 and balance in oxidant/antioxidant process and inhibited vascular dysfunction, when compared with the l–NAME group. Moreover, no significant differences were detected in the HSP72 level between rats in the treadmill exercise and FG groups. These results provide a rationale for an inhibitory role and a cardioprotective effect of lifestyle related to the health in the attenuation of hypertension-induced cardiotoxicity.

Heat exposure induces tissue stress in heat-intolerant, but not heat-tolerant, mice

We investigated the association of systemic and local tissue stress responses with heat–tolerant (TOL) levels in mice. Thirty-eight mice were assigned into control and three heat exposure groups—TOL, moderately tolerant, and intolerant (INT), based on their overall thermal responses. Real-time core temperature, blood pressure, and heart rate (HR) were assessed during heat exposure (39.5°C) under conscious condition. Tissue samples were collected 18–22 h following heat exposure. INT mice had significantly higher peak mean arterial pressure and HR than TOL mice during heat exposure. Plasma corticosterone levels were significantly higher in INT than in control mice. No significant changes in plasma cytokines or markers of oxidative status were observed. INT mice showed significant increases in HSP72 and HSP90 protein and mRNA levels in liver, heart, and gastrocnemius muscles compared to TOL and control mice. In contrast, INT mice had significantly lower heat shock factor 1 and glucocorticoid receptor protein and mRNA levels in these tissues than TOL and control mice. These results indicate that acute heat exposure induces stress responses in various tissues of INT mice, but not TOL mice. Upregulation of stress proteins by acute heat exposure involves both transcriptional and translational pathways.

Heat exposure causes a complex stress response in heat‐intolerant mice

We investigated the association between heat‐induced stress responses and heat tolerance levels in mice. Thirty‐eight mice were assigned into control and three heat exposure groups ‐ tolerant (TOL), moderately tolerant (MT) and intolerant (INT), based on their thermal responses. Real‐time core temperature, blood pressure, and heart rate were assessed during heat exposure (120 min at 39.5°C) under conscious condition. Tissue samples were collected 18–22 hours following heat exposure. INT mice had significantly higher peak mean arterial pressure and heart rate than TOL mice during heat exposure. Plasma corticosterone levels were significantly higher in INT than control mice. No changes in plasma cytokines or markers of oxidative status were observed. INT mice showed significant increases in HSP72 and HSP90 protein and mRNA levels in liver, heart and gastrocnemius muscles compared to TOL and control mice. In contrast, INT mice had significantly lower HSF1 and glucocorticoid receptor protein and mRNA levels in these tissues than TOL and control mice. These results suggest that heat exposure causes an extensive stress response in mice with heat intolerance. Complex transcriptional and translational processes are involved in mediation of heat‐induced stress. (supported by ONR N0001411MP20025 and USUHS R091EH)

Hypoxia-mediated prior induction of monocyte-expressed HSP72 and HSP32 provides protection to the disturbances to redox balance associated with human sub-maximal aerobic exercise

HSP72 is rapidly expressed in response to a variety of stressors in vitro and in vivo (including hypoxia). This project sought a hypoxic stimulus to elicit increases in HSP72 and HSP32 in attempts to confer protection to the sub-maximal aerobic exercise-induced disturbances to redox balance. Eight healthy recreationally active male subjects were exposed to five consecutive days of once-daily hypoxia (2,980 m, 75 min). Seven days prior to the hypoxic acclimation period, subjects performed 60 min of cycling on a cycle ergometer (exercise bout 1-EXB1), and this exercise bout was repeated 1 day post-cessation of the hypoxic period (exercise bout 2-EXB2). Blood samples were taken immediately pre- and post-exercise and 1, 4 and 8 h post-exercise for HSP72 and immediately pre, post and 1 h post-exercise for HSP32, TBARS and glutathione [reduced (GSH), oxidised (GSSG) and total (TGSH)], with additional blood samples obtained immediately pre-day 1 and post-day 5 of the hypoxic acclimation period for the same indices. Monocyte-expressed HSP32 and HSP72 were analysed by flow cytometry, with measures of oxidative stress accessed by commercially available kits. There were significant increases in HSP72 (P < 0.001), HSP32 (P = 0.03), GSSG (t = 9.5, P < 0.001) and TBARS (t = 5.6, P = 0.001) in response to the 5-day hypoxic intervention, whereas no significant changes were observed for GSH (P = 0.22) and TGSH (P = 0.25). Exercise-induced significant increases in HSP72 (P < 0.001) and HSP32 (P = 0.003) post-exercise in EXB1; this response was absent for HSP72 (P ≥ 0.79) and HSP32 (P ≥ 0.99) post-EXB2. The hypoxia-mediated increased bio-available HSP32 and HSP72 and favourable alterations in glutathione redox, prior to exercise commencing in EXB2 compared to EXB1, may acquiesce the disturbances to redox balance encountered during the second physiologically identical exercise bout.

Atherosclerosis induced by arsenic in drinking water in rats through altering lipid metabolism

Arsenic in drinking water is a global environmental health problem, and the exposure may increase cardiovascular and cerebrovascular diseases mortalities, most likely through causing atherosclerosis. However, the mechanism of atherosclerosis formation after arsenic exposure is still unclear. To study the mechanism of atherosclerosis formation after arsenic exposure and explore the role of high cholesterol diet (HCD) in this process, we fed spontaneous hypertensive rats and Wistar Kyoto rats with basal diet or HCD and provided with them drinking water containing arsenic at different ages and orders for 20 consecutive weeks. We measured high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), total cholesterol, triglycerides, heat shock protein 70 (HSP 70), and high sensitive C-reactive protein (hs-CRP) at predetermined intervals and determined expressions of cholesteryl ester transfer protein-1 (CETP-1) and liver X receptor β (LXRβ) in the liver. Atherosclerosis was determined by examining the aorta with hematoxylin and eosin stain. After 20 weeks, we found arsenic, alone or combined with HCD, may promote atherosclerosis formation with transient increases in HSP 70 and hs-CRP. Early combination exposure decreased the HDL-C/LDL-C ratio without changing the levels of total cholesterol and triglyceride until 30 weeks old. Both CETP-1 and LXRβ activities were suppressed, most significantly in early combination exposure. In conclusion, arsenic exposure may induce atherosclerosis through modifying reverse cholesterol transport in cholesterol metabolism and suppressing LXRβ and CEPT-1 expressions. For decreasing atherosclerosis related mortality associated with arsenic, preventing exposure from environmental sources in early life is an important element.

Hold Me Tight

Hold Me Tight

Cardiomyoplasty: preservation of the latissimus dorsi muscle.

Muscle necrosis has been frequently observed in cardiomyoplasty patients and in experimental animal studies. The purpose of this study was to determine if heat shock could provide protection to skeletal muscle as has been shown in cardiac muscle. A 15-minute heat shock at 42 degrees C resulted in an immediate increase in HSP72 mRNA and was followed within 3 hours by a two-fold increase in HSP72. Surgical dissection of the latissimus dorsi muscle (LDM) followed by an ischemic period resulted in a two-fold increase in HSP72 in control LDM, whereas the already high levels in the heat-shocked LDM increased only slightly with surgery and ischemia. Citrate synthase activity and tissue histology indicated that heat shock did not protect the LDM from the imposed surgical trauma and ischemia insults used in this study.

Heat Shock Protein in Developing Grains in Relation to Thermotolerance for Grain Growth in Wheat

AbstractWheat (Triticum aestivum L.) cvs DL 153‐2 and HD 2285 (relatively tolerant), HD 2329 and WH 542 (relatively susceptible), were grown under normal (27 November) and late (28 December) sown conditions. In another experiment, these cultivars were grown under normal sowing and at anthesis stage, they were transferred to control (C) and heated (H) open top chambers (OTCs). Under late sowing, wheat cultivars were exposed to a mean maximum temperature of up to 3.6 °C higher than normal sowing and in H‐OTCs, mean maximum temperature was 3.2 °C higher than C‐OTCs during grain growth period. Heat susceptibility index (S) for grain growth and grain yield was determined at maturity in both the experiments. The level of heat shock protein (HSP 18) in the developing grains was determined in C‐ and H‐OTC grown plants and in normal and late sown plants by Western blot analysis. The moderately high temperature exposure increased the accumulation of HSP 18 in the developing grains. The relatively tolerant cultivars, as also revealed from S, showed a greater increase in HSP 18 compared with susceptible types in response to moderate heat stress. An association of HSP 18 with thermotolerance for grain growth in wheat was indicated.

Both heat shock and water deprivation trigger Hsp70 expression in the olfactory lobe of the crab Chasmagnathus granulatus

Heat-shock proteins (Hsp) are synthesized in the central nervous system in response to traumas but also after physical exercise and psychophysiological stress. Therefore, an increase in Hsp expression is a good marker of changes in metabolic activity. In the crab Chasmagnathus, a powerful memory paradigm has been established. Memory modulation is possible by water shortage. The brain areas activated by either training protocols and/or water-deprivation are still unknown. Hsp expression might be a marker to sensing the increase in metabolic activity in crab Chasmagnathus brain neuropils engaged in the physiological responses triggered by water deprivation and cognitive processing. Here, we observed an increase in brain Hsp of 70kDa (Hsp70) expression after a heat-shock treatment. Additionally, immunohistochemistry analysis revealed that, under basal conditions, some glomeruli of the olfactory lobes showed Hsp70 immunoreactivity in an on-off manner. Both a hot environment and water deprivation increased the number of glomeruli expressing Hsp70. This marker of neuropil's activity might turn out to be a powerful tool to test whether crustacean olfactory lobes not only process olfactory information but also integrate multimodal signals.

Does Whole Body Heat Acclimation Change Peripheral Blood Mononuclear Cell Thermotolerance?

In isolated cell and animal studies, a single exposure to sublethal heat stress protects them from a subsequent lethal heat shock. This increase in thermotolerance is associated with intracellular accumulation of heat shock protein 72 (Hsp72). In humans, whole body heat acclimation (HA), which involves exercise in hot environments for several days, increases intracellular Hsp72. However, it is not known if whole body HA is able to increase thermotolerance in isolated human peripheral blood mononuclear cells (PBMC). PURPOSE: To determine if HA alters in vitro PBMC thermotolerance. We hypothesized that HA would increase PBMC tolerance to heat. METHODS: 7 male and 2 female subjects (mean ± SD, age 24 ± 3 yrs, 75 ± 5 kg, 53 ± 8 mL.kg-1.min−1) were heat acclimated by walking or running on a treadmill (56% VO2max) for 100 minutes (two 50 min exercise bouts separated by 15 min of rest) in a hot environment (42°C and 30% rh) for 10 days. Blood was drawn, and PBMC were separated and cultured on days 1 and 10 of HA pre-and post-exercise. 24 hours later, pre-exercise PBMC were incubated in a hot water bath (42.5°C for 2 hours). Intracellular Hsp72 was assayed by ELISA. Lactate dehydrogenase (LDH) was measured as a marker of cell damage. RESULTS: HA was confirmed by the classic signs of attenuated (p<0.05) peak heart rate, skin and core temperatures on day 1 vs. day 10 of HA. LDH release increased (p<0.05) after 42.5°C for 2 hours but it was not different between days 1 and 10 of HA (1.11 ± 0.08 and 1.10 ± 0.10 relative LDH release, respectively). Pre-exercise Hsp72 was higher (p<0.05) on day 10 compared to day 1 of HA (13 ± 5 and 8 ± 5 ng.mL−1, respectively). Post-exercise Hsp72 was not different (p>0.05) on day 1 compared to day 10 of HA (13 ± 5 and 17 ± 8 ng.mL−1, respectively). Heat stressing the pre-exercise PBMC to 42.5°C for 2 hours induced a greater increase in Hsp72 than post-exercise (p<0.05), and it was greater on day 1 than day 10 of HA (129 ± 46 and 80 ± 32 ng.mL−1, respectively). CONCLUSION: Whole body HA increases intracellular Hsp72 but it does not reduce cell damage to heat, as measured by LDH. We suggest that the heat stress applied during HA is not sufficient to induce enough Hsp72 to improve cell thermotolerance. Supported by GSSI student award and NIH grant AR40771.

Reverse Regulation of Endothelial Cells and Myointimal Hyperplasia on Cell Proliferation by a Heatshock Protein-Coinducer After Hypoxia

Myointimal hyperplasia (MIH) cells are related to permanent upregulated proliferation as tumor-like cells. The aim of this study is to assess whether treatment of cells after hypoxia by Iroxanadine heat-shock protein (HSP-coinducer) predicts recovery through cell proliferation. Vascular smooth muscle cells (VSMC) and brain capillary endothelial cells (HBEC) were isolated from human origin and MIH-cells from early carotid restenosis after surgery. Cell proliferation was quantified by bromuridine (BrdU) incorporation after hypoxia/reoxygenation. HSP72 and cyclin-dependent kinase (CDKN1A) mRNA expression was assessed by reverse transcription-polymerase chain reaction (PCR) and cell cycle distribution by flow cytometry (FACS) analysis. After hypoxia/reoxygenation, the proliferation of MIH-cells increased, whereas endothelial cells decreased (MIH: 0.266+/-0.016 versus 0.336+/-0.024; P<0.05; HBEC: 1.249+/-0.10 versus 0.878+/-0.11; P<0.05). Whereas augmented proliferation of MIH-cells was reduced (40% to 45%) by HSP-coinducer, diminished HBEC proliferation increased (46.2%). Stress-activated-protein-kinase (SAPK)p38-dependent cell cycle redistribution was generated by an increase in HSP72 and CDKN1A mRNA levels in MIH-cells. The 2 key players of early restenosis (MIH, EC) were oppositely regulated and correspondingly after treatment by HSP-coinducer reverse recovered. Drug candidate may have therapeutic potential in (re)restenosis.

Hsp72 is neuroprotective in the the anoxia tolerant turtle, Trachemys scripta elegans

Cardiac ischemia, stroke and some neurodegenerative disorders are all characterized by cell damage and death due to low oxygen levels. Heat shock proteins, Hsp72 in particular, are neuroprotective in species from the fruit fly to humans. While increases in Hsp72 and Hsc73 have been reported in anoxia in the highly anoxia-tolerant turtle Trachemys scripta, the protective role of these stress proteins in cell death has yet to be determined. We examined the levels of Hsp72 in neuronally enriched primary cell cultures established from the turtle, and utilized siRNA to knockdown Hsp72 in vitro. Hsp72 protein and RNA levels increased during late anoxia (4 hours) and prolonged anoxia (16hour) with respect to normoxic controls. As in the whole brain, significant levels of Hsp72 protein were observed even in normoxia, which increased 2 to 3-fold after 16 hours of anoxia (P<0.05) indicating a probable role in long-term anoxic cell survival. SiRNA mediated knockdown of Hsp72 resulted in increased cell death compared to controls in both anoxic cells and following reoxygenation after 4 hours anoxia, as evidenced by Propidium Iodide (PI) staining. Hsp72 knockdown has also resulted in increased ROS release upon reoxygenation (P<0.05) in a dose dependent manner, implicating Hsp72 as a key element of anoxic and reoxygenation cell survival that does play a role in the suppression of ROS production. The mechanisms by which Hsp72 promotes neuronal survival in anoxia and reoxygenation are currently under investigation.