Hsp70 and cardiac surgery: molecular chaperone and inflammatory regulator with compartmentalized effects

Mitochondrial unfolded protein response mechanism and its cardiovascular protective effects

The mitochondrial unfolded protein response (UPRmt) is a cytoprotective response in response to cellular stress that is activated in response to mitochondrial stress to maintain intra-protein homeostasis, thereby protecting the cell from a variety of stimuli. The activation of this response has been linked to cardiovascular diseases. Here, we reviewed the current understanding of UPRmt and discussed its specific molecular mechanism, mainly in mammals, as well as addressing its protective role against cardiovascular diseases, so as to provide direction for further research on UPRmt and therapies targeting cardiovascular diseases in the future.

Pre-exercise hot water immersion increased circulatory heat shock proteins but did not alter muscle damage markers or endurance capacity after eccentric exercise

Pre-exercise passive heating attenuates muscle damage caused by eccentric exercise in rats where the induction of heat shock proteins (HSPs) confers a myoprotective effect. We investigated whether pre-exercise hot water immersion (HWI) confers similar benefits in humans. Eleven recreational male athletes were immersed in 41°C water up to 60 min or until rectal temperatures reached 39.5°C. After a 6 h rest, the participants performed an eccentric downhill run for 1 h at -4% gradient to induce muscle damage. An endurance capacity test at 75% VO2max was conducted 18 h later. The control trial was similar except that participants were immersed at 34°C. Blood samples were collected to assess HSPs levels, creatine kinase, and lactate dehydrogenase activities. Plasma eHSP70 was higher post-immersion in HWI trials (1.3 ± 0.4 vs 1.1 ± 0.4; p = 0.005). Plasma eHSP27 was higher before (p = 0.049) and after (p = 0.015) endurance test in HWI. Leukocytic p-HSP27 was increased 18 h after HWI (0.97 ± 0.14 vs 0.67 ± 0.11; p = 0.04). Creatine kinase and lactate dehydrogenase activities were increased by 3-fold and 1.5-fold, respectively, after endurance test in HWI but did not differ across trials (p > 0.05). Mean heart rates were higher during eccentric run and endurance test in HWI as compared to control (p < 0.05). Endurance capacity was similar between trials (57.3 ± 11.5 min vs 55.0 ± 13.5 min; p = 0.564). Pre-exercise heating increased the expression of plasma eHSPs and leukocytic p-HSP27 but did not reduce muscle damage nor enhance endurance capacity.

Emerging role of heat shock proteins in cardiovascular diseases

Heat Shock Proteins (HSPs) are evolutionarily conserved proteins from prokaryotes to eukaryotes. They are ubiquitous proteins involved in key physiological and cellular pathways (viz. inflammation, immunity and apoptosis). Indeed, the survivability of the cells under various stressful conditions depends on appropriate levels of HSP expression. There is a growing line of evidence for the role of HSPs in regulating cardiovascular diseases (CVDs) (viz. hypertension, atherosclerosis, atrial fibrillation, cardiomyopathy and heart failure). Furthermore, studies indicate that a higher concentration of circulatory HSP antibodies correlate to CVDs; some are even potential markers for CVDs. The multifaceted roles of HSPs in regulating cellular signaling necessitate unraveling their links to pathophysiology of CVDs. This review aims to consolidate our understanding of transcriptional (via multiple transcription factors including HSF-1, NF-κB, CREB and STAT3) and post-transcriptional (via microRNAs including miR-1, miR-21 and miR-24) regulation of HSPs. The cytoprotective nature of HSPs catapults them to the limelight as modulators of cell survival. Yet another attractive prospect is the development of new therapeutic strategies against cardiovascular diseases (from hypertension to heart failure) by targeting the regulation of HSPs. Moreover, this review provides insights into how genetic variation of HSPs can contribute to the manifestation of CVDs. It would also offer a bird's eye view of the evolving role of different HSPs in the modulation and manifestation of cardiovascular disease.

Relationship between HSPA1A-regulated gene expression and alternative splicing in mouse cardiomyocytes and cardiac hypertrophy

Background

Cardiac hypertrophy may be classified as either physiological or pathological. Pathological hypertrophy has a complex etiology and is genetically regulated. In this study, we used a mouse model of cardiac hypertrophy to explore the mechanisms of gene regulation, in particular, modulation of the expression of target genes through transcription factor activity, regulation of immune and inflammation-associated genes and regulation of the alternative splicing of transcription factors.

Methods

Mouse models of pathological cardiac hypertrophy were established by transverse aortic constriction (TAC). We overexpressed HSPA1A in mouse cardiac HL-1 cells. GO and KEGG pathway annotation database was used to analyze all DEGs.

Results

The expression of HSPA1A differed significantly between TAC + dantrolene vs. sham + dantrolene (Sham was the non-TAC group, and DMSO was the contrast agent), and TAC + DMSO vs. sham + DMSO. The RNA-binding protein Zfp36 was found to be differentially expressed between both TAC + dantrolene vs. sham + dantrolene and TAC + DMSO vs. sham + DMSO. The expression of mki67 and gm5619 was significantly different between TAC + dantrolene and TAC + DMSO. HSPA1A was found to selectively regulate the expression of non-coding RNAs related to cardiac hypertrophy, including Rn7sk and RMRP. The downregulated genes were mainly related to inflammation and the immune response. HSPA1A negatively regulated alternative splicing of Asxl2 and positively regulated alternative splicing of Runx1.

Conclusions

HSPA1A was closely related to cardiac hypertrophy. Zfp36 was also related to cardiac hypertrophy. Dantrolene may delay cardiac hypertrophy and ventricular remodeling by regulating the expression of the RNA-binding protein genes mki67 and gm5619. HSPA1A positively regulated the expression of the non-coding RNAs RN7SK and RMRP while negatively regulating the expression of inflammation- and immune response-related genes. HSPA1A can play a role in cardiac hypertrophy by regulating the alternative splicing of asxl2 and runx1.

Heat Shock Proteins: Connectors between Heart and Kidney

Over the development of eukaryotic cells, intrinsic mechanisms have been developed in order to provide the ability to defend against aggressive agents. In this sense, a group of proteins plays a crucial role in controlling the production of several proteins, guaranteeing cell survival. The heat shock proteins (HSPs), are a family of proteins that have been linked to different cellular functions, being activated under conditions of cellular stress, not only imposed by thermal variation but also toxins, radiation, infectious agents, hypoxia, etc. Regarding pathological situations as seen in cardiorenal syndrome (CRS), HSPs have been shown to be important mediators involved in the control of gene transcription and intracellular signaling, in addition to be an important connector with the immune system. CRS is classified as acute or chronic and according to the first organ to suffer the injury, which can be the heart (CRS type 1 and type 2), kidneys (CRS type 3 and 4) or both (CRS type 5). In all types of CRS, the immune system, redox balance, mitochondrial dysfunction, and tissue remodeling have been the subject of numerous studies in the literature in order to elucidate mechanisms and propose new therapeutic strategies. In this sense, HSPs have been targeted by researchers as important connectors between kidney and heart. Thus, the present review has a focus to present the state of the art regarding the role of HSPs in the pathophysiology of cardiac and renal alterations, as well their role in the kidney–heart axis.

Heat Shock Protein 70 (HSP70) Induction: Chaperonotherapy for Neuroprotection after Brain Injury

The 70 kDa heat shock protein (HSP70) is a stress-inducible protein that has been shown to protect the brain from various nervous system injuries. It allows cells to withstand potentially lethal insults through its chaperone functions. Its chaperone properties can assist in protein folding and prevent protein aggregation following several of these insults. Although its neuroprotective properties have been largely attributed to its chaperone functions, HSP70 may interact directly with proteins involved in cell death and inflammatory pathways following injury. Through the use of mutant animal models, gene transfer, or heat stress, a number of studies have now reported positive outcomes of HSP70 induction. However, these approaches are not practical for clinical translation. Thus, pharmaceutical compounds that can induce HSP70, mostly by inhibiting HSP90, have been investigated as potential therapies to mitigate neurological disease and lead to neuroprotection. This review summarizes the neuroprotective mechanisms of HSP70 and discusses potential ways in which this endogenous therapeutic molecule could be practically induced by pharmacological means to ultimately improve neurological outcomes in acute neurological disease.

Edaravone-Loaded Macrophage-Derived Exosomes Enhance Neuroprotection in the Rat Permanent Middle Cerebral Artery Occlusion Model of Stroke

Edaravone (Edv) can inhibit tissue damage, cause cerebral edema, and delay neuronal death caused by acute cerebral infarction. Exosomes are considered as cargo carriers for intercellular communication and serve as important regulators in many pathological processes. Here, we developed macrophage-derived exosomes (Exo) containing Edv (Exo + Edv) to improve the bioavailability of Edv and enhance the neuroprotective effects in a rat model of permanent middle cerebral artery occlusion (PMCAO). The results showed that Exo + Edv significantly improved the bioavailability of Edv and prolonged half-life (t_1/2). At the same time, Exo + Edv made Edv more easily reach the ischemic side of rats with PMCAO and was localized with neuronal cells and microglia, thus reducing the death of neuronal cells and promoting the polarization of microglia from M1 to M2. Taken together, Exo + Edv may become a potential clinical treatment option for PMCAO.

Inhibition of heat shock protein 70 blocks the development of cardiac hypertrophy by modulating the phosphorylation of histone deacetylase 2

AIMS

Previously, we reported that phosphorylation of histone deacetylase 2 (HDAC2) and the resulting activation causes cardiac hypertrophy. Through further study of the specific binding partners of phosphorylated HDAC2 and their mechanism of regulation, we can better understand how cardiac hypertrophy develops. Thus, in the present study, we aimed to elucidate the function of one such binding partner, heat shock protein 70 (HSP70).

METHODS AND RESULTS

Primary cultures of rat neonatal ventricular cardiomyocytes and H9c2 cardiomyoblasts were used for in vitro cellular experiments. HSP70 knockout (KO) mice and transgenic (Tg) mice that overexpress HSP70 in the heart were used for in vivo analysis. Peptide-precipitation and immunoprecipitation assay revealed that HSP70 preferentially binds to phosphorylated HDAC2 S394. Forced expression of HSP70 increased phosphorylation of HDAC2 S394 and its activation, but not that of S422/424, whereas knocking down of HSP70 reduced it. However, HSP70 failed to phosphorylate HDAC2 in the cell-free condition. Phosphorylation of HDAC2 S394 by casein kinase 2α1 enhanced the binding of HSP70 to HDAC2, whereas dephosphorylation induced by the catalytic subunit of protein phosphatase 2A (PP2CA) had the opposite effect. HSP70 prevented HDAC2 dephosphorylation by reducing the binding of HDAC2 to PP2CA. HSP70 KO mouse hearts failed to phosphorylate S394 HDAC2 in response to isoproterenol infusion, whereas Tg overexpression of HSP70 increased the phosphorylation and activation of HDAC2. 2-Phenylethynesulfonamide (PES), an HSP70 inhibitor, attenuated cardiac hypertrophy induced either by phenylephrine in neonatal ventricular cardiomyocytes or by aortic banding in mice. PES reduced HDAC2 S394 phosphorylation and its activation by interfering with the binding of HSP70 to HDAC2.

CONCLUSION

These results demonstrate that HSP70 specifically binds to S394-phosphorylated HDAC2 and maintains its phosphorylation status, which results in HDAC2 activation and the development of cardiac hypertrophy. Inhibition of HSP70 has possible application as a therapeutic.

Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress

The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (-11 to 43 °C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42 °C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.

Heat shock protein signaling in brain ischemia and injury

Heat shock proteins (HSPs) are chaperones that catalyze the refolding of denatured proteins. In addition to their ability to prevent protein denaturation and aggregation, the HSPs have also been shown to modulate many signaling pathways. Among HSPs, the inducible 70 kDa HSP (HSP70) has especially been shown to improve neurological outcome in experimental models of brain ischemia and injury. HSP70 can modulate various aspects of the programmed cell death pathways and inflammation. This review will focus on potential mechanisms of the neuroprotective effects of HSP70 in stroke and brain trauma models. We also comment on potential ways in which HSP70 could be translated into clinical therapies.

Extracellular Hsp70 modulates the inflammatory response of cigarette smoke extract in NCI-H292 cells

NEW FINDINGS

What is the central question of this study? Does extracellular heat shock protein 70 (eHsp70) alter cigarette smoke extract (CSE)-induced inflammatory responses in NCI-H292 bronchial epithelial cells? What is the main finding and its importance? eHsp70 modulates inflammatory responses and TLR2, TLR4 and Hsp70 gene expression, and protects NCI-H292 cells against CSE-induced cytotoxicity. eHsp70 might be implicated in development of inflammatory diseases affected by cigarette smoke, such as COPD.

ABSTRACT

One of the major risk factors for development of chronic obstructive pulmonary disease (COPD) is cigarette smoke. Extracellular Hsp70 (eHsp70) is increased in sera of COPD patients, and can act as damage-associated molecular pattern (DAMP). In this study, we explored inflammatory parameters (cytokine concentrations, Toll-like receptor (TLR) 2 and 4 and Hsp70 expression, mitogen-activated protein kinases (MAPKs) and nuclear factor κB (NF-κB) activation, and cytotoxicity) after exposure of bronchial-epithelial NCI-H292 cells to cigarette smoke extract (CSE) alone (2.5 and 15%) and in combinations with recombinant human (rh) Hsp70 (0.3, 1 and 3 μg ml^-1 ). We applied specific MAPKs, NF-κB and Hsp70 inhibitors to elucidate rhHsp70 inflammation-associated responses. CSE alone and combinations of 15% CSE with rhHsp70 stimulated IL-1α, IL-6 and IL-8 release. However, rhHsp70 applied with 2.5% CSE decreased secretion of cytokines indicating antagonistic effects. Individual and combined treatments with 2.5% CSE suppressed TLR2 expression. CSE at 15% induced TLR2 and TLR4 gene expression, whereas rhHsp70 abolished that effect. rhHsp70 and 15% CSE alone reduced, while their combination increased, intracellular Hsp70 mRNA level. CSE alone and in combination with rhHsp70 activated extracellular signal-regulated kinase and p38 MAPKs, while inhibition of MAPKs, NF-κB and Hsp70 attenuated IL-6 and IL-8 secretion. CSE at 15% reduced cell viability and induced apoptosis, as shown by MTS and caspases-3/7 assays. CSE at 2.5% alone stimulated lactate dehydrogenase release, but cellular membrane integrity remained intact in co-treatments with rhHsp70. rhHsp70 might modulate the inflammatory response of CSE and could also protect NCI-H292 cells against CSE cytotoxicity. Those effects are implemented via MAPK and NF-κB signalling pathways.

Camel whey protein protects lymphocytes from apoptosis via the PI3K–AKT, NF-κB, ATF-3, and HSP-70 signaling pathways in heat-stressed male mice

Heat stress (HS) is an environmental factor that depresses the immune systems that mediate dysfunctional immune cells. Camel whey protein (CWP) can scavenge free radicals and enhance immunity. This study investigated the impact of dietary supplementation with CWP on immune dysfunction induced by exposure to HS. Male mice (n = 45) were distributed among 3 groups: control group; HS group; and HS mice that were orally administered CWP (HS + CWP group). The HS group exhibited elevated levels of reactive oxygen species (ROS) and pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumor necrosis factor-α) as well as a significant reduction in the IL-2 and IL-4 levels. Exposure to HS resulted in impaired phosphorylation of AKT and IκB-α (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha); increased expression of activating transcription factor 3 (ATF-3) and 70 kDa heat shock proteins (HSP70); and aberrant distribution of CD3+ T cells and CD20+ B cells in the thymus and spleen. Interestingly, HS mice treated with CWP presented significantly restored levels of reactive oxygen species and pro-inflammatory cytokines near the levels observed in the control mice. Furthermore, supplementation of HS mice with CWP enhanced the phosphorylation of AKT and IκB-α; attenuated the expression of ATF-3, HSP70, and HSP90; and improved T and B cell distributions in the thymus and spleen. Our findings reveal a potential immunomodulatory effect of CWP in attenuating immune dysfunction induced by exposure to thermal stress.

The role of heat shock proteins and co-chaperones in heart failure

The ongoing contractile and metabolic demands of the heart require a tight control over protein quality control, including the maintenance of protein folding, turnover and synthesis. In heart disease, increases in mechanical and oxidative stresses, post-translational modifications (e.g., phosphorylation), for example, decrease protein stability to favour misfolding in myocardial infarction, heart failure or ageing. These misfolded proteins are toxic to cardiomyocytes, directly contributing to the common accumulation found in human heart failure. One of the critical class of proteins involved in protecting the heart against these threats are molecular chaperones, including the heat shock protein70 (HSP70), HSP90 and co-chaperones CHIP (carboxy terminus of Hsp70-interacting protein, encoded by the Stub1 gene) and BAG-3 (BCL2-associated athanogene 3). Here, we review their emerging roles in the maintenance of cardiomyocytes in human and experimental models of heart failure, including their roles in facilitating the removal of misfolded and degraded proteins, inhibiting apoptosis and maintaining the structural integrity of the sarcomere and regulation of nuclear receptors. Furthermore, we discuss emerging evidence of increased expression of extracellular HSP70, HSP90 and BAG-3 in heart failure, with complementary independent roles from intracellular functions with important therapeutic and diagnostic considerations. While our understanding of these major HSPs in heart failure is incomplete, there is a clear potential role for therapeutic modulation of HSPs in heart failure with important contextual considerations to counteract the imbalance of protein damage and endogenous protein quality control systems.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

The 70-kDa heat shock protein (Hsp70) as a therapeutic target for stroke

INTRODUCTION

The 70-kDa heat shock protein (Hsp70) is a cytosolic chaperone which facilitates protein folding, degradation, complex assembly, and translocation. Following stroke, these functions have the potential to lead to cytoprotection, and this has been demonstrated using genetic mutant models, direct gene transfer or the induction of Hsp70 via heat stress, approaches which limit its translational utility. Recently, the investigation of Hsp70-inducing pharmacological compounds, which, through their ability to inhibit Hsp90, has obvious clinical implications in terms of potential therapies to mitigate cell death and inflammation, and lead to neuroprotection from brain injury. Areas covered: In this review, we will focus on the role of Hsp70 in cell death and inflammation, and the current literature surrounding the pharmacological induction in acute ischemic stroke models with comments on potential applications at the clinical level. Expert opinion: Such neuroprotectants could be used to synergistically improve neurological outcome or to extend the time window of existing interventions, thus increasing the numbers of stroke victims eligible for treatment.

Correlation between blood, physiological and behavioral parameters in beef calves under heat stress

Objective

The performance, health, and behaviour of cattle can be strongly affected by climate. The objective of this study was to determine the effect of heat stress on blood parameters, blood proteins (haptoglobin [Hp]; heat shock protein 70 [HSP70]), rectal temperature (RT), heart rate (HR) and rumination time in Korean native beef calves.

Methods

Thirty-two Korean native beef calves were randomly assigned to 8 groups with 4 animals per group. They were kept in environmental condition with temperature-humidity index (THI) ranging from 70.01 to 87.72 in temperature-humidity controlled chamber for 7 days.

Results

Their HR, RT, and serum cortisol and HSP70 levels were increased (p<0.05) in high THI compared to those at low THI. But, serum Hp level was decreased (p<0.05) in high THI compared to these at low THI. In addition, HR, RT, serum cortisol and HSP70 were positively correlated with THI (R² = 0.8368, p<0.01; R² = 0.6162, p<0.01; R² = 0.581, p<0.01; R² = 0.2241, p = 0.0062, respectively). There was also positive association between HR and cortisol (R² = 0.4697, p<0.01). Similarly, RT and cortisol were positively associated (R² = 0.4581, p<0.01). But, THI and HR were negatively correlated with Hp (R² = 0.2157, p = 0.02; R² = 0.3362, p = 0.003). Hematology and metabolites results were different among treatment groups. Standing position was higher (p<0.05) in the high THI group compared to that in the low THI group.

Conclusion

Based on these results, it can be concluded that HR, RT, blood parameters (Cortisol, HSP70, Hp) and standing position are closely associated with heat stress. These parameters can be consolidated to develop THI chart for Korean native beef calves.

Anti-inflammatory effect of lovastatin is mediated via the modulation of NF-κB and inhibition of HDAC1 and the PI3K/Akt/mTOR pathway in RAW264.7 macrophages

Lovastatin is a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor that is clinically used for the prevention of cardiovascular diseases. Although it has been reported that lovastatin has anti-inflammatory properties in several studies, how lovastatin regulates the inflammation is still unclear. To evaluate the effect of lovastatin on nitric oxide production (NO) in RAW264.7 macrophages, NO production assay was performed. Also, cell viability was measured to confirm cytotoxicity. Level of tumor necrosis factor-α (TNF-α) transcription was measured by reverse transcription polymerase chain reaction (RT-PCR) from total RNA in RAW264.7 cells. Western blot analysis and immunofluorescence staining were used to investigate the regulation of lovastatin on the expression, phosphorylation, and nuclear translocation of cellular proteins. The results of the present study revealed that lovastatin reduced nitric oxide production via the reduction of inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. The mRNA level of TNF-α was reduced in presence of lovastatin. In addition, lovastatin downregulated histone deacetylase 1 (HDAC1), resulting in the accumulation of acetylated histone H3 and heat shock protein 70. Furthermore, the expression of phosphoinositide 3-kinase catalytic subunits α and β was reduced under lovastatin treatment, and the phosphorylation of Akt and mammalian target of rapamycin was consequently inhibited. Lovastatin also inhibited the phosphorylation of inhibitor of nuclear factor (NF)-κBα and the translocation of NF-κB into the nucleus. Therefore, the present study demonstrates that lovastatin inhibits the expression of pro-inflammatory mediators, including iNOS and TNF-α, through the suppression of HDAC1 expression, PI3K/Akt phosphorylation and NF-κB translocation in LPS-stimulated RAW264.7 macrophage cells.

Heart irradiation reduces microvascular density and accumulation of HSPA1 in mice

PURPOSE

Improvement of radiotherapy techniques reduces the exposure of normal tissues to ionizing radiation. However, the risk of radiation-related late effects remains elevated. In the present study, we investigated long-term effects of radiation on heart muscle morphology.

MATERIALS AND METHODS

We established a mouse model to study microvascular density (MVD), deposition of collagen fibers, and changes in accumulation of heat shock 70 kDa protein 1 (HSPA1) in irradiated heart tissue. Hearts of C57BL/6 mice received a single dose of X‑ray radiation in the range 0.2-16 Gy. Analyses were performed 20, 40, and 60 weeks after irradiation.

RESULTS

Reduction in MD was revealed as a long-term effect observed 20-60 weeks after irradiation. Moreover, a significant and dose-dependent increase in accumulation of HSPA1, both cytoplasmic and nuclear, was observed in heart tissues collected 20 weeks after irradiation. We also noticed an increase in collagen deposition in hearts treated with higher doses.

CONCLUSIONS

This study shows that some changes induced by radiation in the heart tissue, such as reduction in microvessel density, increase in collagen deposition, and accumulation of HSPA1, are observed as long-term effects which might be associated with late radiation cardiotoxicity.

HSP70: therapeutic potential in acute and chronic cardiac disease settings

Heat shock proteins are a family of proteins that are produced by cells in response to exposure to stressful conditions. The best studied heat shock protein is HSP70, which is known to act as a molecular chaperone to maintain cellular homeostasis and inhibit protein aggregation in response to stress. While early animal studies suggested that increasing HSP70 in the heart (using a transgenic, gene transfer or pharmacological approach) provided cardiac protection against acute cardiac stress, recent studies have found no benefit of increasing HSP70 in mouse models of chronic cardiac stress. As HSP70 has been considered a potential therapeutic target, it is important to comprehensively assess HSP70 therapies in preclinical models of acute and chronic cardiac disease.

Expression of HSP70 genes in skin of zebu (Tharparkar) and crossbred (Karan Fries) cattle during different seasons under tropical climatic conditions

Skin is most important environmental interface providing a protective envelope to animals. It's always under the influence of both internal and external stressors. Heat shock proteins (HSP) are highly conserved stress proteins which play crucial roles in environmental stress tolerance and thermal adaptation. Present study was planned to observe the relative mRNA expression of inducible (HSP70.1 and HSP70.2) and constitutive (HSP70.8) HSP in skin of zebu (Tharparkar) and crossbred (Karan Fries) cattle during different seasons. Skin biopsies were collected from rump region of each animal, aseptically during winter, spring and summer season. Quantitative real time polymerase chain reaction was performed to examine the gene expression of constitutive (HSP70.8) and inducible (HSP70.1 and HSP70.2) HSP in skin of both the breeds during different seasons. Present study observed higher expression of both constitutive and inducible HSP genes in both the breeds during summer and winter than spring season, but magnitude of increase was higher during summer than winter. During summer season, expression pattern of HSPs in skin showed breed differences, where constitutive HSP expression was higher in Tharparkar than Karan Fries and that of inducible HSP was higher in Karan Fries than Tharparkar. Hence, present study suggested that HSP may be conveniently used as biomarkers for assessing protective response of skin against heat stress in zebu and crossbred cattle. Variation in expression between breeds is associated with their heat tolerance and thermal adaptability. In summary, skin of zebu cattle (Tharparkar) is more resistant to summer stress than crossbred (Karan Fries), providing greater protection against heat stress during summer season. Superior skin protective mechanism of zebu (Tharparkar) than crossbred (Karan-Fries) cattle against heat stress may contribute to superior adaptability of zebu cattle to tropical climatic conditions than crossbreed.

Heat shock protein 72 may improve hypotension by increasing cardiac mechanical efficiency and arterial elastance in heatstroke rats

OBJECTIVE

We attempted to test the hypothesis that preinduction of heat shock protein (HSP) 72 in the heart would improve left ventricular performance in rat heatstroke.

METHODS

Cardiac expression of HSP 72 was quantitatively evaluated by western blot analysis in rats 0h, 12h, or 72h after mild heat preconditioning (MHP; 43°C for 30min). They were subjected to severe heat stress (SHS; 43°C for 70min) to induce heatstroke. A 1.2F catheter-tip pressure transducer was inserted into the left ventricle of these group rats under general anesthesia to record hemodynamic in the closed chest with a pressure-volume loop module data recording and analysis system.

RESULTS

At the time point of heatstroke onset, compared with normothermic controls, group rats with 12h post-MHP had significantly increased cardiac HSP 72, decreased hyperthermia, decreased hypotension, decreased bradycardia, increased end-systolic pressure, increased end-diastolic pressure, increased stroke volume, decreased end-systolic volume, decreased end-diastolic pressure, increased cardiac output, increased ejection fraction, increased stroke work, increased arterial elastance, and decreased time constant of fall in ventricular pressure by Glantz-methods. With the loss of cardiac HSP 72 expression observed at 72h in post-MHP group rats, an insignificant protection against left ventricular performance was observed.

CONCLUSION

Preinduction of cardiac HSP 72 may improve hypotension in heatstroke rats by increasing both cardiac mechanical efficiency and arterial elastance.

An in vitro model to consider the effect of 2 mM glutamine and KNK437 on endotoxin-stimulated release of heat shock protein 70 and inflammatory mediators

OBJECTIVE

Glutamine has been shown to promote the release of heat shock protein 70 (HSP70) both within experimental in vitro models of sepsis and in adults with septic shock. This study aimed to investigate the effects of 2 mM glutamine and an inhibitor of HSP70 (KNK437) on the release of HSP70 and inflammatory mediators in healthy adult volunteers.

METHODS

An in vitro whole blood endotoxin stimulation assay was used.

RESULTS

The addition of 2 mM glutamine significantly increased HSP70 levels over time (P < 0.05). HSP70 release had a positive correlation at 4 h with IL-1 β (r = 0.51, P = 0.03) and an inverse correlation with TNF-α (r = -0.56, P = 0.02) and IL-8 levels (r = -0.52, P = 0.03), and there were no significant correlations between HSP70 and IL6 or IL-10 or glutamine. Glutamine supplementation significantly (P < 0.05) attenuated the release of IL-10 at 4 h and IL-8 at 24 h, compared with conditions without glutamine. In endotoxin-stimulated blood there were no significant differences in the release of IL-6, TNF-α, and IL-1 β with glutamine supplementation at 4 and 24 h. However, glutamine supplementation (2 mM) appeared to attenuate the release of inflammatory mediators (IL-1 β, IL-6, TNF-α), although this effect was not statistically significant. The addition of KNK437, a HSP70 inhibitor, significantly diminished HSP70 release, which resulted in lower levels of inflammatory mediators (P < 0.05).

CONCLUSION

Glutamine supplementation promotes HSP70 release in an experimental model of sepsis. After the addition of KNK437, the effects of glutamine on HSP70 and inflammatory mediator release appear to be lost, suggesting that HSP70 in part orchestrates the inflammatory mediator response to sepsis. The clinical implications require further investigation.

Cardiac and hepatic role of r-AtHSP70: basal effects and protection against ischemic and sepsis conditions

Heat shock proteins (HSPs), highly conserved in all organisms, act as molecular chaperones activated by several stresses. The HSP70 class of stress-induced proteins is the most studied subtype in cardiovascular and inflammatory disease. Because of the high similarity between plant and mammalian HSP70, the aim of this work was to evaluate whether recombinant HSP70 of plant origin (r-AtHSP70) was able to protect rat cardiac and hepatic function under ischemic and sepsis conditions. We demonstrated for the first time that, in ex vivo isolated and perfused rat heart, exogenous r-AtHSP70 exerted direct negative inotropic and lusitropic effects via Akt/endothelial nitric oxide synthase pathway, induced post-conditioning cardioprotection via Reperfusion Injury Salvage Kinase and Survivor Activating Factor Enhancement pathways, and did not cause hepatic damage. In vivo administration of r-AtHSP70 protected both heart and liver against lipopolysaccharide-dependent sepsis, as revealed by the reduced plasma levels of interleukin-1β, tumour necrosis factor alpha, aspartate aminotransferase and alanine aminotransferase. These results suggest exogenous r-AtHSP70 as a molecular modulator able to protect myocardial function and to prevent cardiac and liver dysfunctions during inflammatory conditions.

Does pharmacotherapy influence the inflammatory responses during cardiopulmonary bypass in children?

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response syndrome (SIRS) by factors such as contact of the blood with the foreign surface of the extracorporeal circuit, hypothermia, reduction of pulmonary blood flow during CPB and endotoxemia. SIRS is maintained in the postoperative phase, co-occurring with a counter anti-inflammatory response syndrome. Research on the effects of drugs administered before the surgery, especially in the induction phase of anesthesia, as well as drugs used during extracorporeal circulation, has revealed that they greatly influence these postoperative inflammatory responses. A better understanding of these processes may not only improve postoperative recovery but also enable tailor-made pharmacotherapy, with both health and economic benefits. In this review, we describe the pathophysiology of SIRS and counter anti-inflammatory response syndrome in the light of CPB in children and the influence of drugs used on these syndromes.

Calcitriol exerts anti-inflammatory effects in keratinocytes treated with autoantibodies from a patient with bullous pemphigoid

BACKGROUND

The hormonally active vitamin D metabolite calcitriol and its analogues exert potent effects on cellular differentiation and regulation of immune responses. Although topical vitamin D analogues are widely used for treatment of psoriasis and vitamin D has been increasingly implicated in prevention and protection from several autoimmune diseases, experimental and clinical data in autoimmune bullous diseases are generally lacking.

OBJECTIVE

Here, we investigated the effects of calcitriol on keratinocytes treated by bullous pemphigoid (BP) autoantibodies.

METHODS

Human keratinocyte (HaCaT) cells were treated with purified human BP or normal IgG from one BP patient and healthy subject, respectively, in the absence or presence of calcitriol and effects on (i) cell viability, (ii) IL-6 and IL-8 secretion, (iii) STAT3 and NFκB activation, (iv) heat shock protein 70 (Hsp70) level, and (v) vitamin D receptor (VDR) expression were studied.

RESULTS

We found that BP IgG-induced IL-6 and IL-8 release from HaCaT cells was reduced in the presence of non-toxic doses of calcitriol. Additionally, calcitriol blunted BP IgG-mediated STAT3 phosphorylation and NFκB activity, whereas Hsp70 and VDR expression were not affected.

CONCLUSION

Although the results of this study are based on autoantibodies prepared from a single patient, they show that calcitriol protects from BP IgG-induced inflammatory processes in vitro, thus favouring its potential inclusion into the therapeutic repertoire of BP.

Oxidative stress-induced expression of HSP70 contributes to the inhibitory effect of 15d-PGJ2 on inducible prostaglandin pathway in chondrocytes

The inhibitory effect of 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) on proinflammatory gene expression has been extensively documented and frequently ascribed to its ability to prevent NF-κB pathway activation. We and others have previously demonstrated that it was frequently independent of the peroxisome proliferator activated receptor (PPAR)γ activation. Here, we provide evidence that induction of intracellular heat shock protein (HSP)70 by oxidative stress is an additional regulatory loop supporting the anti-inflammatory effect of 15d-PGJ2 in chondrocytes. Using real-time quantitative PCR and Western blotting, we showed that 15d-PGJ2 stimulated HSP70, but not HSP27 expression while increasing oxidative stress as measured by spectrofluorimetry and confocal spectral imaging. Using N-acetylcysteine (NAC) as an antioxidant, we demonstrated further that oxidative stress was thoroughly responsible for the increased expression of HSP70. Finally, using an HSP70 antisense strategy, we showed that the inhibitory effect of 15d-PGJ2 on IL-1-induced activation of the NF-κB pathway, COX-2 and mPGES-1 expression, and PGE2 synthesis was partly supported by HSP70. These data provide a new anti-inflammatory mechanism to support the PPARγ-independent effect of 15d-PGJ2 in chondrocyte and suggest a possible feedback regulatory loop between oxidative stress and inflammation via intracellular HSP70 up-regulation. This cross talk is consistent with 15d-PGJ2 as a putative negative regulator of the inflammatory reaction.

Hsp90 blockade modulates bullous pemphigoid IgG-induced IL-8 production by keratinocytes

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering skin disease characterized by autoantibodies against the hemidesmosomal proteins BP180 and BP230. The cell stress chaperone heat shock protein 90 (Hsp90) has been implicated in inflammatory responses, and recent evidence suggests that it represents a novel treatment target in autoimmune bullous diseases. The aim of the study was to investigate the contribution of Hsp90 to the proinflammatory cytokine production in keratinocytes induced by autoantibodies to BP180 from BP patient serum. HaCaT cells were treated with purified human BP or normal IgG in the absence or presence of the Hsp90 blocker 17-DMAG and effects on viability, interleukin 6 (IL-6) and IL-8 (cytokines critical for BP pathology), NFκB (their major transcription factor), and Hsp70 (marker of effective Hsp90 inhibition and potent negative regulator of inflammatory responses) were investigated. We found that BP IgG stimulated IL-6 and IL-8 release from HaCaT cells and that non-toxic doses of 17-DMAG inhibited this IL-8, but not IL-6 secretion in a dose- and time-dependent fashion. Inhibition of this IL-8 production was also observed at the transcriptional level. In addition, 17-DMAG treatment blunted BP IgG-mediated upregulation of NFκB activity and was associated with Hsp70 induction. This study provides important insights that Hsp90 is involved as crucial regulator in anti-BP180 IgG-induced production of keratinocyte-derived IL-8. By adding to the knowledge of the multimodal anti-inflammatory effects of Hsp90 blockade, our data further support the introduction of Hsp90 inhibitors into the clinical setting for treatment of autoimmune diseases, especially for BP.

Lysosomal storage diseases and the heat shock response: convergences and therapeutic opportunities

Lysosomes play a vital role in the maintenance of cellular homeostasis through the recycling of cell constituents, a key metabolic function which is highly dependent on the correct function of the lysosomal hydrolases and membrane proteins, as well as correct membrane lipid stoichiometry and composition. The critical role of lysosomal functionality is evident from the severity of the diseases in which the primary lesion is a genetically defined loss-of-function of lysosomal hydrolases or membrane proteins. This group of diseases, known as lysosomal storage diseases (LSDs), number more than 50 and are associated with severe neurodegeneration, systemic disease, and early death, with only a handful of the diseases having a therapeutic option. Another key homeostatic system is the metabolic stress response or heat shock response (HSR), which is induced in response to a number of physiological and pathological stresses, such as protein misfolding and aggregation, endoplasmic reticulum stress, oxidative stress, nutrient deprivation, elevated temperature, viral infections, and various acute traumas. Importantly, the HSR and its cardinal members of the heat shock protein 70 family has been shown to protect against a number of degenerative diseases, including severe diseases of the nervous system. The cytoprotective actions of the HSR also include processes involving the lysosomal system, such as cell death, autophagy, and protection against lysosomal membrane permeabilization, and have shown promise in a number of LSDs. This review seeks to describe the emerging understanding of the interplay between these two essential metabolic systems, the lysosomes and the HSR, with a particular focus on their potential as a therapeutic target for LSDs.

Inhibitory effects of heat shock protein 90 blockade on proinflammatory human Th1 and Th17 cell subpopulations

Background

Heat shock protein 90 (Hsp90), a chaperone that regulates activity of many client proteins responsible for cellular growth, differentiation, and apoptosis, has been proposed as an important clinical and preclinical therapeutic target in a number of malignancies and autoimmune diseases, respectively. In this study, we evaluated the effects of pharmacological Hsp90 inhibition on human proinflammatory T cell responses.

Findings

Using anti-CD3 antibody-stimulated human peripheral blood mononuclear cell cultures, we observed that Hsp90 inhibition by non-toxic concentrations of the geldanamycin derivative 17-DMAG significantly blocked T cell proliferation, reduced IFN-γ and IL-17 expression on CD4⁺ T lymphocytes, and arrested secretion of proinflammatory IFN-γ, TNF-α, and IL-17, cytokines characteristic of Th1 and Th17 cells, respectively. These effects were associated with inhibition of NF-kB activity, upregulation of Hsp70 protein expression, and disruption of T cell-specific nonreceptor tyrosine kinase Lck activation.

Conclusions

Our results further support the potential use of Hsp90 inhibitors in patients with autoimmune diseases where uncontrolled Th1 or Th17 activation frequently occurs.

Cancer in heart disease patients: what are the limitations in the treatment strategy?

Cardiovascular disease and cancer are leading causes of morbidity and mortality, and can both be present in one patient. In patients with simultaneous disease, the most threatening disease should be treated first. This is usually heart disease, but this can pose specific problems. If percutaneous coronary intervention is preferred, bleeding and thrombotic tendencies have to be taken into account in the subsequent treatment of the malignancy. With coronary artery bypass grafting, the advantages and disadvantages of one- or two-stage procedures, and the use of extracorporeal circulation have to be balanced. Development of heart disease after treatment of malignancy could be due to radiotherapy and chemotherapy. The effects of these cancer treatments have to be taken into account for the treatment options of the heart disease and the postoperative prognosis.

Control and target gene selection for studies on UV-induced genotoxicity in whales

BACKGROUND

Despite international success in reducing ozone-depleting emissions, ultraviolet radiation (UV) is not expected to decrease for several decades. Thus, it is pressing to implement tools that allow investigating the capacity of wildlife to respond to excessive UV, particularly species like cetaceans that lack anatomical or physiological protection. One approach is to examine epidermal expression of key genes involved in genotoxic stress response pathways. However, quantitation of mRNA transcripts requires previous standardization, with accurate selection of control and target genes. The latter is particularly important when working with environmental stressors such as UV that can activate numerous genes.

RESULTS

Using 20 epidermal biopsies from blue, fin and sperm whale, we found that the genes encoding the ribosomal proteins L4 and S18 (RPL4 and RPS18) were the most suitable to use as controls, followed by the genes encoding phosphoglycerate kinase 1 (PGK1) and succinate dehydrogenase complex subunit A (SDHA). A careful analysis of the transcription pathways known to be activated by UV-exposure in humans and mice led us to select as target genes those encoding for i) heat shock protein 70 (HSP70) an indicator of general cell stress, ii) tumour suppressor protein P53 (P53), a transcription factor activated by UV and other cell stressors, and iii) KIN17 (KIN), a cell cycle protein known to be up-regulated following UV exposure. These genes were successfully amplified in the three species and quantitation of their mRNA transcripts was standardised using RPL4 and RPS18. Using a larger sample set of 60 whale skin biopsies, we found that the target gene with highest expression was HSP70 and that its levels of transcription were correlated with those of KIN and P53. Expression of HSP70 and P53 were both related to microscopic sunburn lesions recorded in the whales' skin.

CONCLUSION

This article presents groundwork data essential for future qPCR-based studies on the capacity of wildlife to resolve or limit UV-induced damage. The proposed target genes are HSP70, P53 and KIN, known to be involved in genotoxic stress pathways, and whose expression patterns can be accurately assessed by using two stable control genes, RPL4 and RPS18.

The long pentraxin PTX3: a candidate anti-inflammatory mediator in cardiac surgery

Coronary artery bypass grafting (CABG) is performed with the use of cardiopulmonary bypass (CPB) and cardioplegic arrest (CA) of the heart. The advantage of this technique, alternatively referred to as “on-pump” surgery, resides, for the surgeon, in relatively easy access to and manipulation with the non-beating, bloodless heart. However, the advantage that is, thereby, gained by the patient is paid off by an increased susceptibility to postoperative systemic inflammatory response syndrome (SIRS). Under unfavorable conditions, the inflammatory syndrome may develop into life-threatening forms of MODS (multiple organ dysfunction syndrome) or even MOFS (multiple organ failure syndrome). Deliberate avoidance of CPB, also known as “off-pump” surgery, attenuates early postoperative inflammation throughout its trajectory of SIRS→MODS→MOFS, but, in the long run, there appears to be no substantial difference in the overall mortality rates. In the last years, our knowledge of the pathophysiology of surgical inflammation has increased considerably. Recent findings, highlighting the as yet rather obscure role of pentraxin 3 (PTX3) in these processes, are discussed in this review article.

Toll-like receptors and opportunities for new sepsis therapeutics

Serious infection and the patient's response (sepsis) is a serious health problem that, even today, is associated with a mortality rate of 30 %-50 %. The phases of severe sepsis include an early hyperinflammatory response to pathogens and a late immunosuppressed phase. Toll-like receptors (TLRs) are a family of transmembrane innate immune receptors that play a major role in both phases of sepsis. Here, their physiology and the therapeutic strategies employed to date are reviewed. Currently, there are no approved therapies targeting TLRs, but it is anticipated that in the future, the less-studied TLRs, such as TLR3, TLR7, and TLR9, will evolve therapeutic targets, perhaps predominantly with agonists, versus the usual antagonist strategies. Furthermore, accurately characterizing the stage of sepsis will be essential to directing appropriate therapeutic choices.

The role of heat shock protein 90 in modulating ischemia-reperfusion injury in the kidney

INTRODUCTION

Kidney transplantation is the gold standard treatment for end-stage renal disease. Ischemia-reperfusion injury (IRI) is an unavoidable consequence of the transplantation procedure and is responsible for delayed graft function and poorer long-term outcomes.

AREAS COVERED

Pharmacological induction of heat shock protein (Hsp) expression is an emerging pre-conditioning strategy aimed at reducing IRI following renal transplantation. Hsp90 inhibition up-regulates protective Hsps (especially Hsp70) and potentially down-regulates NF-κB by disruption of the IκB kinase (IKK) complex. However, the clinical application of Hsp90 inhibitors is currently limited by their toxicity profile and the exact mechanism of protection conferred is unknown. Toll-like receptor 4 (TLR4) is a further regulator of NF-κB and recent studies suggest TLR4 plays a dominant role in mediating kidney damage following IRI. The full interaction of Hsps with TLRs is yet to be delineated and whether TLR4 signalling can be targeted by Hsp90 inhibition in IRI remains uncertain.

EXPERT OPINION

Pharmacological pre-conditioning by Hsp90 inhibition involves direct treatment to the kidney donor and/or organ, which aims to reduce injury prior to the onset of ischemia. The major challenges going forward are to establish the exact mechanism of protection offered by these drugs and the investgiation of less toxic analogues that could be safely translated into human studies.

Heat shock protein 70 induced by heat stress protects heterotopically transplanted hearts in rats

Heat shock protein 70 (HSP70) protects cardiac function against ischemia-reperfusion injury through gene transfection, although it is not a clinically practical and economical method. This study investigated whether heat stress-induced HSP70 protects heterotopically transplanted donor hearts. A total of 60 donor rats were randomly divided into 6 groups. Five of those received heat stress and one was a control group. Donor hearts were heterotopically transplanted into recipient rats at five time points, following the heat stress (0, 24, 48, 96 and 192 h). The levels of HSP70 expression in donor hearts and the variation of myocardial enzymes in receptor blood or donor hearts were measured 24 h after transplantation. The donated hearts were also examined under a microscope for pathological changes. HSP70 expression was the highest in the 24-h group (p≤0.01) and decreased gradually in the 48- and 96-h groups. No statistically significant difference was found in the HSP70 expression in the control, the 0- and 192-h groups (p≥0.05). Of all the groups, the 24-h group had the lowest lactate dehydrogenase and creatine kinase muscle band concentrations in receptor blood. Moreover, this group showed the lowest malondialdehyde concentration and the highest atriphosphate concentration (p≤0.01), demonstrated by the mildest inflammatory injury in the transplanted hearts. We found a time-dose-effect relationship among heat stress, HSP70 and the protection of donor hearts. Heat stress is a practical method that can be clinically applied to protect donor hearts against ischemia-reperfusion injury by inducing endogenous HSP70, which indicates the future direction of clinical practice.

The Toll-like receptor 9 ligand CPG-C attenuates acute inflammatory cardiac dysfunction

Stimulation of toll-like receptor 9 (TLR9) by CpG-C containing oligonucleotides attenuates ischemic injury in the brain and liver. In this study, we investigate whether any of the three classes of CpG (A, B, or C) mitigate ischemia-induced cardiac dysfunction. We measured left ventricular ejection fraction (LVEF) in C57BL/6 mice using transthoracic echocardiography. Using LPS as an inflammatory stimulus, CpG-C was uniquely able to prevent cardiac dysfunction; its activity was confirmed through nuclear factor κB transcriptional activity assay in HL-1 cardiomyocytes. We went on to investigate CpG-C's efficacy and mechanism in the treatment of ischemia-reperfusion. Compared with baseline, no class of CpG significantly altered LVEF at 6 or 24 h; 40 mg/kg LPS induced a rapid, profound suppression of LVEF compared with baseline (26% ± 1.4% vs. 65% ± 1.4%), whereas pretreatment with CpG demonstrated that of the three classes, only CpG-C prevented the LPS -induced decrease in LVEF (51% ± 5.8%). In separate mice, 1-h ischemia followed by reperfusion of the left anterior descending artery resulted in a 7-day suppression of the LVEF (66% ± 5.2% at baseline; 46% ± 4.7% at day 1, and 46% ± 4.0% at day 7), whereas mice either pretreated with or begun on an infusion of CpG-C during the ischemia had no significant decline in LVEF. Gene expression microarray of CpG-C-stimulated cells revealed upregulation of the nuclear factor κB pathway inhibitors TNFAIP3, NFKBIA, TRIM30, and TNIP1. These may play a role in attenuation of cardiac inflammation. The TLR9 ligand CpG-C attenuates the acute inflammatory cardiac dysfunction induced by both LPS and ischemia-reperfusion of the left anterior descending artery.

Heat shock protein 90 inhibition by 17-DMAG lessens disease in the MRL/lpr mouse model of systemic lupus erythematosus

Elevated expression of heat shock protein 90 (HSP90) has been found in kidneys and serum of systemic lupus erythematosus (SLE) patients and MRL/Mp-Fas(lpr)/Fas(lpr) (MRL/lpr) autoimmune mice. We investigated if inhibition of HSP90 would reduce disease in MRL/lpr mice. In vitro, pretreatment of mesangial cells with HSP90 inhibitor Geldanamycin prior to immune-stimulation showed reduced expression of IL-6, IL-12 and NO. In vivo, we found HSP90 expression was elevated in MRL/lpr kidneys when compared to C57BL/6 mice and MRL/lpr mice treated with HSP90 inhibitor 17-DMAG. MRL/lpr mice treated with 17-DMAG showed decreased proteinuria and reduced serum anti-dsDNA antibody production. Glomerulonephritis and glomerular IgG and C3 were not significantly affected by administration of 17-DMAG in MRL/lpr. 17-DMAG increased CD8(+) T cells, reduced double-negative T cells, decreased the CD4/CD8 ratio and reduced follicular B cells. These studies suggest that HSP90 may play a role in regulating T-cell differentiation and activation and that HSP90 inhibition may reduce inflammation in lupus.

Heat shock proteins: conditional mediators of inflammation in tumor immunity

Heat shock protein (HSP)-based anticancer vaccines have undergone successful preclinical testing and are now entering clinical trial. Questions still remain, however regarding the immunological properties of HSPs. It is now accepted that many of the HSPs participate in tumor immunity, at least in part by chaperoning tumor antigenic peptides, introducing them into antigen presenting cells such as dendritic cells (DC) that display the antigens on MHC class I molecules on the cell surface and stimulate cytotoxic lymphocytes (CTL). However, in order for activated CD8+ T cells to function as effective CTL and kill tumor cells, additional signals must be induced to obtain a sturdy CTL response. These include the expression of co-stimulatory molecules on the DC surface and inflammatory events that can induce immunogenic cytokine cascades. That such events occur is indicated by the ability of Hsp70 vaccines to induce antitumor immunity and overcome tolerance to tumor antigens such as mucin1. Secondary activation of CTL can be induced by inflammatory signaling through Toll-like receptors and/or by interaction of antigen-activated T helper cells with the APC. We will discuss the role of the inflammatory properties of HSPs in tumor immunity and the potential role of HSPs in activating T helper cells and DC licensing.

Heat shock attenuates VEGF expression in three-dimensional myoblast sheets deteriorating therapeutic efficacy in heart failure

Background

Myoblast sheet transplantation is a promising novel treatment for ischemic heart failure. The aim of this study was to test the hypothesis that heat shock (HS) pre-treatment affects the angiogenic properties of myoblast sheets in vivo and in vitro.

Material/Methods

We studied HS preconditioning of L6 myoblast sheets in relation to their apoptosis, proliferation, and vascular endothelial growth factor (VEGF)-associated responses under normoxia and under hypoxia in vitro. In vivo evaluation of their therapeutic effect was performed with 60 male Wistar rats divided into 3 groups (20 each): sole left anterior descending (LAD) ligation (control); LAD ligation and non-conditioned sheet transplantation (L6 No-Shock); and LAD ligation and L6-heat shock conditioned sheet transplantation (L6 Heat-Shock). Left ventricular function was evaluated by echocardiography after 3, 10, and 28 days.

Results

Expression of HSP70/72 was strongly induced 24 hours after HS, and thereafter it decreased notably during 72 hours in hypoxia. Under normal growth conditions, HSP70/72 expression remained stable. HS delayed apoptosis-associated caspase-3 expression during 24-hour hypoxia compared to non-treated controls. However, VEGF expression reduced significantly in the heat shock pretreated sheets. Ejection fraction of the L6-myoblast HS pre-treatment group (L6 Heat-Shock) decreased gradually during follow-up, in the same pattern as the controls. However, these functional parameters improved in the L6-myoblast normal sheet group (L6 No-Shock) at the tenth day and remained significantly better.

Conclusions

HS protects myoblast sheets from hypoxia-associated apoptosis in vitro, but reduces VEGF expression of the sheet, leading to lower therapeutic effect in heart failure.

Prevention and treatment of alopecia areata with quercetin in the C3H/HeJ mouse model

Alopecia areata (AA) is an autoimmune non-scarring hair loss disorder. AA can be acute, recurrent, or chronic. Current therapeutic options for AA are limited, and there is no effective prevention for recurrent AA. We have previously shown a correlation between the expression of HSP70 (HSPA1A/B), a heat shock protein involved in the inflammatory response, and the onset of AA in the C3H/HeJ mouse model. In this study, we tested the effects of quercetin, a bioflavonoid with anti-inflammatory properties, on AA development and HSP70 expression in the C3H/HeJ model. Mice with spontaneous AA were treated with subcutaneous quercetin or sham injections. Hair regrowth was observed in lesional areas in all the quercetin-treated mice, but in none of the sham-treated mice. In addition, non-alopecic C3H/HeJ mice were heat-treated to induce alopecia, along with quercetin or sham injections. Whereas 24% of the heat-treated mice with sham injections developed alopecia, none of the mice receiving quercetin injections did. As expected, the level of HSP70 expression in quercetin-treated areas was comparable to control. Furthermore, we showed that systemic delivery of quercetin by intraperitoneal injections prevented/reduced spontaneous onset of AA. Our results demonstrated that quercetin provided effective treatment for AA as well as prevention of onset of AA in the C3H/HeJ model, and warrant further clinical studies to determine whether quercetin may provide both treatment for preexisting AA and prevention of recurrent AA. The ready availability of quercetin as a dietary supplement may lead to increased patient compliance and positive outcomes for AA.

HSP90 inhibition by 17-DMAG reduces inflammation in J774 macrophages through suppression of Akt and nuclear factor-κB pathways

OBJECTIVE

This study was designed to determine whether inhibition of heat shock protein 90 (HSP90) reduces pro-inflammatory mediator production by decreasing the nuclear factor (NF)-κB and Akt signaling pathways in immune-stimulated macrophages.

METHODS

J774A.1 murine macrophages were treated with the HSP90 inhibitor 17-DMAG (0.01, 0.1 or 1 μM) prior to immune stimulation with lipopolysaccharide and interferon-γ. Expression of Akt, inhibitor of κB kinase (IKK), and heat shock proteins were measured in whole cell lysates by Western blotting. Phosphorylated Akt and inhibitor of κB (IκB) were measured in whole cell lysates by ELISA. Cell supernatants were analyzed for interleukin (IL)-6, tumor necrosis factor (TNF)-α and nitric oxide (NO). Translocation of NF-κB and heat shock factor (HSF)-1 was assessed by immunofluorescence.

RESULTS

Treating cells with 17-DMAG reduced expression of Akt and IKK in immune-stimulated cells. 17-DMAG reduced nuclear translocation of NF-κB and reduced immune-stimulated production of IL-6, TNF-α and NO, but did not decrease inducible nitric oxide synthase expression.

CONCLUSIONS

Our studies show that the immune-mediated NF-κB inflammatory cascade is blocked by the HSP90 inhibitor 17-DMAG. Due to the broad interaction of HSP90 with many pro-inflammatory kinase cascades, inhibition of HSP90 may provide a novel approach to reducing chronic inflammation.

Salvianolic acid B inhibits the TLR4-NFκB-TNFα pathway and attenuates neonatal rat cardiomyocyte injury induced by lipopolysaccharide

OBJECTIVE

To investigate the role of the TLR4-NFκB-TNFα inflammation pathway on: lipopolysaccharide (LPS)-induced neonatal rat cardiomyocyte injury and the possible protective effects of salvianolic acid B (Sal B).

METHODS

Wistar rat (1-2 days old) cardiomyocytes were isolated and cultured. Sal B 10(-5)mol/L, 10(-6)mol/L and 10(-7)mol/L were pre-treated for 6 h in the culture medium. LPS (1 μg/mL) was added to mol/the culture medium and kept for 6 h to induce inflammation injury. The concentration of lactate dehydrogenase (LDH) in the supernatant was detected by spectrophotometry. The concentrations of tumor necrosis factor α (TNFα) and heat shock protein 70 (HSP70) in the supernatant were detected by enzyme linked immunosorbent assay. The protein expressions of toll, such as receptor 4 (TLR4) and nuclear factor kappa B (NFκB) were detected by immunohistochemistry. The mRNA expressions of TLR4 and NFκB were detected by real-realtime reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

(1) The concentrations of LDH and: TNFα in the LPS control group were significantly higher than those in the control group (561.41±67.39 U/L and 77.94±15.08 pg/mL, versus 292.13±26.02 U/L and 25.39±16.53 pg/mL, respectively, P<0.01, P<0.05). Compared with the LPS control group, the concentrations of LDH and TNFα were significantly decreased in the Sal B 10(-5)mol/L pre-treated group (451.76±83.96 U/L and 34.00±10.38 pg/mL, respectively, P<0.05). (2) The TLR4 and NFκB protein expression area in the LPS control group were significantly higher than those in the control group (1712.41±410.12 μm(2) and 2378.15±175.29 μm(2), versus 418.62±24.42 μm(2) and 1721.74±202.87 μm(2), respectively, P<0.01). The TLR4 and NFκB protein expression internal optical density (IOD) values in the LPS control group were also significantly higher than those in the control group (3.06±0.33 and 7.20±1.04, versus 0.91±0.21 and 4.24±0.48, respectively, P<0.05 and P<0.01). Compared with the LPS control group, the TLR4 and NFκB protein expression areas were significantly decreased in the Sal B 10(-5)mol/L pre-treated group (1251.54±133.82 μm(2) and 1996.37±256.67 μm(2), respectively, P<0.05), the TLR4 and NFκB protein expression IOD values were also significantly decreased in the Sal B 10(-5)mol/L pre- mol/pretreated group (1.92±0.28 and 5.17±0.77, respectively, treated P<0.05). (3) The TLR4 and NFκB mRNA expressions (2(-ΔΔ)CT value) in the LPS control group were significantly higher than those in the control group (3.16±0.38 and 5.03±0.43 versus 1.04±0.19 and 1.08±0.21, respectively, P<0.01). Compared with the LPS control group, the TLR4 and NFκB mRNA expressions (2(-ΔΔ) -CT value) were significantly decreased in the Sal B 10(-5)mol/L pre- mol/pretreated group (1.34±0.22 and 1.74±0.26, respectively, treated P<0.05). The concentration of HSP70 did not show any <statistical differences in all groups (P>0.05).

CONCLUSIONS

The TLR4-NFκB-TNFα pathway was quickly activated: and was independent of HSP70 in the early phase of neonatal cardiomyocyte injury induced by LPS. The protective effects of Sal B may be through inhibiting the TLR4-NFκB-TNFα pathway and are dose-dependent.

Pediatric Sepsis - Part V: Extracellular Heat Shock Proteins: Alarmins for the Host Immune System

Heat shock proteins (HSPs) are molecular chaperones that facilitate the proper folding and assembly of nascent polypeptides and assist in the refolding and stabilization of damaged polypeptides. Through these largely intracellular functions, the HSPs maintain homeostasis and assure cell survival. However, a growing body of literature suggests that HSPs have important effects in the extracellular environment as well. Extracellular HSPs are released from damaged or stressed cells and appear to act as local "danger signals" that activate stress response programs in surrounding cells. Importantly, extracellular HSPs have been shown to activate the host innate and adaptive immune response. With this in mind, extracellular HSPs are commonly included in a growing list of a family of proteins known as danger-associated molecular patterns (DAMPs) or alarmins, which trigger an immune response to tissue injury, such as may occur with trauma, ischemia-reperfusion injury, oxidative stress, etc. Extracellular HSPs, including Hsp72 (HSPA), Hsp27 (HSPB1), Hsp90 (HSPC), Hsp60 (HSPD), and Chaperonin/Hsp10 (HSPE) are especially attractrive candidates for DAMPs or alarmins which may be particularly relevant in the pathophysiology of the sepsis syndrome.