Mechanisms of HSP72 release

Oral CBD-rich hemp extract modulates sterile inflammation in female and male rats

Introduction: Cannabidiol (CBD) extract from the cannabis plant has biomedical and nutraceutical potential. Unlike tetrahydrocannabinol (THC), CBD products produce few psychoactive effects and pose little risk for abuse. There is emerging preclinical and clinical evidence that CBD is stress modulatory and may have anti-inflammatory properties. People across the United States legally ingest CBD-rich hemp extracts to manage mental and physical health problems, including stress and inflammation. Preclinical studies have revealed potential mechanisms for these effects; however, the impact of this prior work is diminished because many studies: 1) tested synthetic CBD rather than CBD-rich hemp extracts containing terpenes and/or other cannabinoids thought to enhance therapeutic benefits; 2) administered CBD via injection into the peritoneal cavity or the brain instead of oral ingestion; and 3) failed to examine potential sex differences. To address these gaps in the literature, the following study tested the hypothesis that the voluntary oral ingestion of CBD-rich hemp extract will attenuate the impact of stressor exposure on plasma and tissue inflammatory and stress proteins in females and males. Methods: Adult male and female Sprague Dawley rats (10-15/group) were randomly assigned to be given cereal coated with either vehicle (coconut oil) or CBD-rich hemp extract (L-M0717, CBDrx/Functional Remedies, 20.0 mg/kg). After 7 days, rats were exposed to a well-established acute model of stress (100, 1.5 mA, 5-s, intermittent tail shocks, 90 min total duration) or remained in home cages as non-stressed controls. Results: Stressor exposure induced a robust stress response, i.e., increased plasma corticosterone and blood glucose, and decreased spleen weight (a surrogate measure of sympathetic nervous system activation). Overall, stress-induced increases in inflammatory and stress proteins were lower in females than males, and oral CBD-rich hemp extract constrained these responses in adipose tissue (AT) and mesenteric lymph nodes (MLN). Consistent with previous reports, females had higher levels of stress-evoked corticosterone compared to males, which may have contributed to the constrained inflammatory response measured in females. Discussion: Results from this study suggest that features of the acute stress response are impacted by oral ingestion of CBD-rich hemp extract in female and male rats, and the pattern of changes may be sex and tissue dependent.

Heat shock protein A2 is a novel extracellular vesicle-associated protein

70-kDa Heat Shock Proteins (HSPA/HSP70) are chaperones playing a central role in the proteostasis control mechanisms. Their basal expression can be highly elevated as an adaptive response to environmental and pathophysiological stress conditions. HSPA2, one of poorly characterised chaperones of the HSPA/HSP70 family, has recently emerged as epithelial cells differentiation-related factor. It is also commonly expressed in cancer cells, where its functional significance remains unclear. Previously, we have found that proteotoxic stress provokes a decrease in HSPA2 levels in cancer cells. In the present study we found that proteasome inhibition-related loss of HSPA2 from cancer cells neither is related to a block in the gene transcription nor does it relate to increased autophagy-mediated disposals of the protein. Proteotoxic stress stimulated extracellular release of HSPA2 in extracellular vesicles (EVs). Interestingly, EVs containing HSPA2 are also released by non-stressed cancer and normal cells. In human urinary EVs levels of HSPA2 were correlated with the levels of TSG101, one of the main EVs markers. We conclude that HSPA2 may constitute basic components of EVs. Nevertheless, its specific role in EVs and cell-to-cell communication requires further investigation.

Potential Role of Chronic Physical Exercise as a Treatment in the Development of Vitiligo

Vitiligo is an autoimmune disease characterized by progressive skin depigmentation and the appearance of white patches throughout the body caused by significant apoptosis of epidermal melanocytes. Despite not causing any physical pain, vitiligo can originate several psychosocial disorders, drastically reducing patients' quality of life. Emerging evidence has shown that vitiligo is associated with several genetic polymorphisms related to auto-reactivity from the immune system to melanocytes. Melanocytes from vitiligo patients suffer from excess reactive oxygen species (ROS) produced by defective mitochondria besides a poor endogenous antioxidant system (EAS). This redox imbalance results in dramatic melanocyte oxidative stress (OS), causing significant damage in proteins, lipid membranes, and DNA. The damaged melanocytes secret damage-associated molecular pattern (DAMPs), inducing and increasing inflammatory gene expression response that ultimately leads to melanocytes apoptosis. Vitiligo severity has been also associated with increasing the prevalence and incidence of metabolic syndrome (MetS) or associated disorders such as insulin resistance and hypercholesterolemia. Thus, suggesting that in genetically predisposed individuals, the environmental context that triggers MetS (i.e., sedentary lifestyle) may also be an important trigger for the development and severity of vitiligo disease. This paper will discuss the relationship between the immune system and epidermal melanocytes and their interplay with the redox system. Based on state-of-the-art evidence from the vitiligo research, physical exercise (PE) immunology, and redox system literature, we will also propose chronic PE as a potential therapeutic strategy to treat and prevent vitiligo disease progression. We will present evidence that chronic PE can change the balance of inflammatory to an anti-inflammatory state, improve both EAS and the mitochondrial structure and function (resulting in the decrease of OS). Finally, we will highlight clinically relevant markers that can be analyzed in a new research avenue to test the potential applicability of chronic PE in vitiligo disease.

Loss of the neuronal genome organizer and transcription factor CTCF induces neuronal death and reactive gliosis in the anterior cingulate cortex

CCCTC-binding factor (CTCF) is a genome organizer that regulates gene expression through transcription and chromatin structure regulation. CTCF also plays an important role during the developmental and adult stages. Cell-specific CTCF deletion studies have shown that a reduction in CTCF expression leads to the development of distinct clinical features and cognitive disorders. Therefore, we knocked out Ctcf (CTCF cKO) in the excitatory neurons of the forebrain in a Camk2a-Cre mouse strain to examine the role of CTCF in cell death and gliosis in the cortex. CTCF cKO mice were viable, but they demonstrated an age-dependent increase in reactive gliosis of astrocytes and microglia in the anterior cingulate cortex (ACC) from 16 weeks of age prior to neuronal loss observed at over 20 weeks of age. Consistent with these data, qRT-PCR analysis of the CTCF cKO ACC revealed changes in the expression of inflammation-related genes (Hspa1a, Prokr2 and Itga8) linked to gliosis and neuronal death. Our results suggest that prolonged Ctcf gene deficiency in excitatory neurons results in neuronal cell death and gliosis, possibly through functional changes in inflammation-related genes.

Association of Plasma Heat Shock Protein 70 with Disease Severity, Smoking and Lung Function of Patients with Chronic Obstructive Pulmonary Disease

Extracellular heat shock protein 70 (eHsp70) might modulate immune responses in chronic obstructive pulmonary disease (COPD). The aim of the study was to explore eHsp70 concentration in stable COPD, its association with disease severity and smoking status as well as its diagnostic performance in COPD assessment. Plasma samples were collected from 137 COPD patients and 95 healthy individuals, and concentration of eHsp70 was assessed by commercially available enzyme-linked immunosorbent assay (ELISA) kit (Enzo Life Science, Farmingdale, NY, USA). COPD patients were subdivided regarding airflow obstruction severity and symptoms severity according to the Global Initiative for COPD (GOLD) guidelines. eHsp70 concentration increased in COPD patients when compared to controls and increased with the severity of airflow limitation as well as symptoms burden and exacerbation history. eHsp70 concentration did not differ among COPD patients based on smoking status, yet it increased in healthy smokers compared to healthy nonsmokers. In addition, eHsp70 negatively correlated with lung function parameters forced expiratory volume in one second (FEV1) and FEV1/ forced vital capacity (FVC), and positively with COPD multicomponent indices BODCAT (BMI, airflow obstruction, dyspnea, CAT score), BODEx (BMI, airflow obstruction, dyspnea, previous exacerbations), CODEx (Charlson's comorbidity index, airflow obstruction, dyspnea, previous exacerbations) and DOSE (dyspnea, airflow obstruction, smoking status, previous exacerbations) With great predictive value (OR = 7.63) obtained from univariate logistic regression, eHsp70 correctly classified 76% of cases. eHsp70 is associated with COPD prediction and disease severity and might have the potential for becoming an additional biomarker in COPD assessment.

The relationship between stress and vitiligo: Evaluating perceived stress and electronic medical record data

Vitiligo is a T-cell mediated skin disorder characterized by progressive loss of skin color. In individuals genetically predisposed to the disease, various triggers contribute to the initiation of vitiligo. Precipitating factors can stress the skin, leading to T-cell activation and recruitment. Though hereditary factors are implicated in the pathogenesis of vitiligo, it is unknown whether precipitating, stressful events play a role in vitiligo. To understand this, we utilized a validated perceived stress scale (PSS) to measure this parameter in vitiligo patients compared to persons without vitiligo. Additionally, we probed a clinical database, using a knowledge linking software called ROCKET, to gauge stress-related conditions in the vitiligo patient population. From a pool of patients in an existing database, a hundred individuals with vitiligo and twenty-five age- and sex-matched comparison group of individuals without vitiligo completed an online survey to quantify their levels of perceived stress. In parallel, patients described specifics of their disease condition, including the affected body sites, the extent, duration and activity of their vitiligo. Perceived stress was significantly higher among vitiligo individuals compared to those without vitiligo. ROCKET analyses suggested signs of metabolic-related disease (i.e., ‘stress’) preceding vitiligo development. No correlation was found between perceived stress and the stage or the extent of disease, suggesting that elevated stress may not be a consequence of pigment loss alone. The data provide further support for stress as a precipitating factor in vitiligo development.

Role of heat shock protein and cytokine expression as markers of clinical outcomes with glutamine-supplemented parenteral nutrition in surgical ICU patients

BACKGROUND

Nutrients, such as glutamine (GLN), have been shown to effect levels of a family of protective proteins termed heat shock proteins (HSPs) in experimental and clinical critical illness. HSPs are believed to serve as extracellular inflammatory messengers and intracellular cytoprotective molecules. Extracellular HSP70 (eHSP70) has been termed a chaperokine due to ability to modulate the immune response. Altered levels of eHSP70 are associated with various disease states. Larger clinical trial data on GLN effect on eHSP expression and eHSP70's association with inflammatory mediators and clinical outcomes in critical illness are limited.

OBJECTIVE

Explore effect of longitudinal change in serum eHSP70, eHSP27 and inflammatory cytokine levels on clinical outcomes such as pneumonia and mortality in adult surgical intensive care unit (SICU) patients. Further, evaluate effect of parenteral nutrition (PN) supplemented with GLN (GLN-PN) versus GLN-free, standard PN (STD-PN) on serum eHSP70 and eHSP27 concentrations.

METHODS

Secondary observational analysis of a multicenter clinical trial in 150 adults after cardiac, vascular, or gastrointestinal surgery requiring PN support and SICU care conducted at five academic medical centers. Patients received isocaloric, isonitrogenous PN, with or without GLN dipeptide. Serum eHSP70 and eHSP27, interleukin-6 (IL-6), and 8 (IL-8) concentrations were analyzed in patient serum at baseline (prior to study PN) and over 28 days of follow up.

RESULTS

eHSP70 declined over time in survivors during 28 days follow-up, but non-survivors had significantly higher eHSP70 concentrations compared to survivors. In patients developing pneumonia, eHSP70, eHSP27, IL-8, and IL-6 were significantly elevated. Adjusted relative risk for hospital mortality was reduced 75% (RR = 0.25, p = 0.001) for SICU patients with a faster decline in eHSP70. The area under the receiver operating characteristic curve was 0.85 (95% CI: 0.76 to 0.94) for the final model suggesting excellent discrimination between SICU survivors and non-survivors. GLN-PN did not alter eHSP70 or eHSP27 serum concentrations over time compared to STD-PN.

CONCLUSION

Our results suggest that serum HSP70 concentration may be an important marker for severity of illness and likelihood of recovery in the SICU. GLN-supplemented-PN did not increase eHSP70.

A longitudinal study of neurotrophic, oxidative, and inflammatory markers in first-onset depression in midlife women

Prospective studies have shown during the years preceding and following menopause, also known as "menopause transition", that midlife women are at higher risk for developing first-onset major depressive disorder (MDD). The biological factors associated with risk and resilience in this population are, however, largely unknown. Considering the growing body of evidence suggesting that inflammation, oxidative stress, and brain-derived neurotrophic factor (BDNF) are associated with the pathophysiology of MDD, we investigated serum levels of protein carbonyl, lipid peroxidation (thiobarbituric acid reactive substances-TBARS), thiol group content, BDNF, 3-nitrotyrosine, and heat shock protein 70 (HSP70) in a longitudinal cohort of first-onset MDD. One hundred and forty-eight women from the Harvard Study of Moods and Cycles, a prospective study of midlife women monitored throughout the transition to menopause, were studied. Within- and between-groups analyses of these peripheral markers were conducted in 37 women who developed and 111 women that did not develop MDD during the 3-year follow-up period. In women who developed MDD, HSP70 and 3-nitrotyrosine were elevated at baseline, whereas TBARS were elevated 6 months prior to development of MDD, as compared to those who did not develop MDD. Within-group analyses showed that HSP70, 3-nitrotyrosine, and BDNF decreased over time, whereas protein carbonyl was elevated only at 12 months prior to development of MDD. In women who did not develop MDD, HSP70 and thiol decreased over time. The development of MDD in midlife women may be associated with a systemic cascade of pro-oxidative and pro-inflammatory events including increased HSP70, 3-nitrotyrosine, protein carbonyl, and lipid peroxidation and decreased BDNF.

Subacute exposure to residual oil fly ash (ROFA) increases eHSP70 content and extracellular-to-intracellular HSP70 ratio: a relation with oxidative stress markers

The purpose of this study was to evaluate whether exposure to particles induces an imbalance in 70-kDa heat shock proteins (HSP70). Since intracellularly (iHSP70) it has anti-inflammatory roles whereas extracellularly (eHSP70) it has pro-inflammatory roles, we evaluate the effect of residual oil fly ash (ROFA) exposure on eHSP70-to-iHSP70 ratio (H index), a biomarker of inflammatory status that is related to oxidative stress in plasma and lymphoid tissue. Wistar rats that received ROFA suspension for three consecutive days (750 μg) showed an increase in plasma eHSP70 levels (mainly the 72-kDa inducible form). Also, ROFA promoted alterations on plasma oxidative stress (increased protein carbonyl groups and superoxide dismutase activity, and decrease sulfhydryl groups). There was an increase in H index of the plasma/thymus with no changes in circulating leukocyte level, iHSP70, or oxidative stress markers in lymphoid tissues. Our results support the hypothesis that eHSP70 content and H index represent inflammatory and oxidative biomarkers.

Hsp70: A Cancer Target Inside and Outside the Cell

Heat shock protein 70 (Hsp70) is the most ubiquitous stress-inducible chaperone. It accumulates in the cells in response to a wide variety of physiological and environmental insults including anticancer chemotherapy, thus allowing the cell to survive to lethal conditions. Intracellular Hsp70 is viewed as a cytoprotective protein. Indeed, this protein can inhibit key effectors of the apoptotic and autophagy machineries. In cancer cells, the expression of Hsp70 is abnormally high, and Hsp70 may participate in oncogenesis and in resistance to chemotherapy. In rodent models, Hsp70 overexpression increases tumor growth and metastatic potential. Depletion or inhibition of Hsp70 frequently reduces the size of the tumors and can even cause their complete involution. However, HSP70 is also found in the extra-cellular space where it may signal via membrane receptors or endosomes to alter gene transcription and cellular function. Overall, Hsp70 extracellular function is believed to be immnunogenic and the term chaperokine to define the extracellular chaperones such as Hsp70 has been advanced. In this chapter the knowledge to date, as well as some emerging paradigms about the intra- and extra-cellular functions of Hsp70, are presented. The strategies targeting Hsp70 that are being developed in cancer therapy will also be discussed.

HSP70 is associated with the severity of inflammation in chronic rhinosinusitis

BACKGROUND

Nasal secretions include cytokines and inflammatory mediators that are involved in the pathogenesis of upper airway inflammation.

OBJECTIVE

We tried to find unknown biomolecules that are involved in the pathogenesis of chronic rhinosinusitis (CRS).

METHODS

We collected nasal mucosal secretions from patients who were diagnosed as having CRS and who underwent endoscopic sinus surgery. A total of 63 patients who underwent nasal secretion collection were reviewed. Enzyme-linked immunosorbent assay was performed by using nasal lavage samples to evaluate which biomolecules were associated with the severity of inflammation based on the Lund-Mackay score. By using human nasal epithelial cells, we performed Western blot, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay to evaluate the secretory mechanism of heat shock protein (HSP) 70.

RESULTS

We found that the level of interleukin 8 and HSP70 were significantly associated with the Lund-Mackay score and interleukin 17C, C-X-C motif chemokine 10, and HSP27 were not significantly associated. HSP70 was also significantly associated with the surgical outcome of the enrolled patients. Furthermore, we found that exposure to hypoxia and treatment of lipoteichoic acid induced the secretion of HSP70 but that lipopolysaccharide did not induce the secretion of HSP70 in human nasal epithelial cells.

CONCLUSION

Our findings indicated that HSP70 might play a role in the pathogenesis of CRS and the possibility of HSP70 as a biomolecule that represents the severity of CRS.

Extracellular Hsp70 Enhances Mesoangioblast Migration via an Autocrine Signaling Pathway

Mouse mesoangioblasts are vessel-associated progenitor stem cells endowed with the ability of multipotent mesoderm differentiation. Therefore, they represent a promising tool in the regeneration of injured tissues. Several studies have demonstrated that homing of mesoangioblasts into blood and injured tissues are mainly controlled by cytokines/chemokines and other inflammatory factors. However, little is known about the molecular mechanisms regulating their ability to traverse the extracellular matrix (ECM). Here, we demonstrate that membrane vesicles released by mesoangioblasts contain Hsp70, and that the released Hsp70 is able to interact by an autocrine mechanism with Toll-like receptor 4 (TLR4) and CD91 to stimulate migration. We further demonstrate that Hsp70 has a positive role in regulating matrix metalloproteinase 2 (MMP2) and MMP9 expression and that MMP2 has a more pronounced effect on cell migration, as compared to MMP9. In addition, the analysis of the intracellular pathways implicated in Hsp70 regulated signal transduction showed the involvement of both PI3K/AKT and NF-κB. Taken together, our findings present a paradigm shift in our understanding of the molecular mechanisms that regulate mesoangioblast stem cells ability to traverse the extracellular matrix (ECM). J. Cell. Physiol. 232: 1845-1861, 2017. © 2016 Wiley Periodicals, Inc.

HSP70 in human polymorphonuclear and mononuclear leukocytes: comparison of the protein content and transcriptional activity of HSPA genes

Cell-type specific variations are typical for the expression of different members of the HSP70 family. In circulating immune cells, HSP70 proteins interact with units of signaling pathways involved in the immune responses and may promote cell survival in sites of inflammation. In this work, we compared basal HSP70 expression and stress-induced HSP70 response in polymorphonuclear and mononuclear human leukocytes. The intracellular content of inducible and constitutive forms of HSP70 was analyzed in relation to the transcriptional activity of HSPA genes. Hyperthermia was used as the stress model for induction of HSP70 synthesis in the cells. Our results demonstrated that granulocytes (mainly neutrophils) and mononuclear cells differ significantly by both basal HSP70 expression and levels of HSP70 induction under hyperthermia. The differences were observed at the levels of HSPA gene transcription and intracellular HSP70 content. The expression of constitutive Hsс70 protein was much higher in mononuclear cells consisting of monocytes and lymphocytes than in granulocytes. At the same time, intact neutrophils showed increased expression of inducible Hsp70 protein compared to mononuclear cells. Heat treatment induced additional expression of HSPA genes in leukocytes. The most pronounced increase in the expression was observed in polymorphonuclear and mononuclear leukocytes for HSPA1A/B. However, in granulocytes, the induction of the transcription of the HSPA8 gene encoding the Hsc70 protein was significantly higher than in mononuclear cells. These variations in transcriptional activity of HSPA genes and intracellular HSP70 content in different populations of leukocytes may reflect specified requirements for the chaperone activity in the cells with a distinct functional role in the immune system.

Heat Shock Protein-70 Expression in Vitiligo and its Relation to the Disease Activity

Background:

Vitiligo is a progressive depigmenting disorder characterized by the loss of functional melanocytes from the epidermis. The etiopathogenesis of vitiligo is still unclear. Heat shock proteins (HSPs) are prime candidates to connect stress to the skin. HSPs were found to be implicated in autoimmune diseases such as rheumatoid arthritis and other skin disorders as psoriasis.

Aim and Objectives:

The aim of this study was to map the level of HSP-70 in vitiligo lesions to declare its role in the pathogenesis and activity of vitiligo.

Materials and Methods:

The study included thirty patients with vitiligo and 30 age- and sex-matched healthy controls. Vitiligo patients were divided as regards to the disease activity into highly active, moderately active, and inactive vitiligo groups. Skin biopsies were taken from the lesional and nonlesional skin of patients and from the normal skin of the controls. HSP-70 messenger RNA (mRNA) expression was estimated using quantitative real-time polymerase chain reaction.

Results:

Our analysis revealed a significantly higher expression of HSP-70 mRNA in lesional skin biopsies from vitiligo patients compared to nonlesional skin biopsies from vitiligo patients (P < 0.001) and compared to skin biopsies from healthy controls (P < 0.001). The level of HSP-70 was not found to be correlated with age, sex, or disease duration. The expression of HSP-70 was correlated with the disease activity and patients with active vitiligo showed higher mean HSP-70 level compared to those with inactive disease.

Conclusions:

HSP-70 plays a role in the pathogenesis of vitiligo and may enhance the immune response in active disease.

Oncogenic extracellular HSP70 disrupts the gap-junctional coupling between capillary cells

High levels of circulating heat shock protein 70 (HSP70) are detected in many cancers. In order to explore the effects of extracellular HSP70 on human microvascular endothelial cells (HMEC), we initially used gap-FRAP technique. Extracellular human HSP70 (rhHSP70), but not rhHSP27, blocks the gap-junction intercellular communication (GJIC) between HMEC, disrupts the structural integrity of HMEC junction plaques, and decreases connexin43 (Cx43) expression, which correlates with the phosphorylation of Cx43 serine residues. Further exploration of these effects identified a rapid transactivation of the Epidermal Growth Factor Receptor in a Toll-Like Receptor 4-dependent manner, preceding its internalization. In turn, cytosolic Ca²⁺ oscillations are generated. Both GJIC blockade and Ca²⁺ mobilization partially depend on ATP release through Cx43 and pannexin (Panx-1) channels, as demonstrated by blocking activity or expression of channels, and inactivating extracellular ATP. By monitoring dye-spreading into adjacent cells, we show that HSP70 released from human monocytes in response to macrophage colony-stimulating factor, prevents the formation of GJIC between monocytes and HMEC. Therapeutic manipulation of this pathway could be of interest in inflammatory and tumor growth.

Gut epithelial inducible heat-shock proteins and their modulation by diet and the microbiota

The epidemic of metabolic diseases has raised questions about the interplay between the human diet and the gut and its microbiota. The gut has two vital roles: nutrient absorption and intestinal barrier function. Gut barrier defects are involved in many diseases. Excess energy intake disturbs the gut microbiota and favors body entry of microbial compounds that stimulate chronic metabolic inflammation. In this context, the natural defense mechanisms of gut epithelial cells and the potential to boost them nutritionally warrant further study. One such important defense system is the activation of inducible heat-shock proteins (iHSPs) which protect the gut epithelium against oxidative stress and inflammation. Importantly, various microbial components can induce the expression of iHSPs. This review examines gut epithelial iHSPs as the main targets of microbial signals and nutrients and presents data on diseases involving disturbances of gut epithelial iHSPs. In addition, a broad literature analysis of dietary modulation of gut epithelial iHSPs is provided. Future research aims should include the identification of gut microbes that can optimize gut-protective iHSPs and the evaluation of iHSP-mediated health benefits of nutrients and food components.

Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm-hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports.

Moderate- and high-intensity exhaustive exercise in the heat induce a similar increase in monocyte Hsp72

This study examined the relationship between exhaustive exercise in the heat at moderate and high intensities on the intracellular heat shock protein 72 (iHsp72) response. Twelve male subjects cycled to exhaustion at 60 and 75% of maximal oxygen uptake in hot conditions (40 °C, 50% RH). iHsp72 concentration was measured in monocytes before, at exhaustion and 24 h after exercise. Rectal temperature, heart rate and oxygen uptake were recorded during exercise. Volitional exhaustion occurred at 58.9 ± 12.1 and 27.3 ± 9.5 min (P < 0.001) and a rectal temperature of 39.8 ± 0.4 and 39.2 ± 0.6 °C (P = 0.002), respectively, for 60 and 75 %. The area under the curve above a rectal temperature of 38.5 °C was greater at 60 % (17.5 ± 6.6 °C min) than 75 % (3.4 ± 4.8 °C min; P < 0.001), whereas the rate of increase in rectal temperature was greater at 75 % (5.1 ± 1.7 vs. 2.2 ± 1.4 °C h(-1); P < 0.001). iHsp72 concentration increased similarly at exhaustion relative to pre-exercise (P = 0.044) and then increased further at 24 h (P < 0.001). Multiple regression analysis revealed no predictor variables associated with iHsp72 expression; however, a correlation was observed between exercise intensities for the increase in iHsp expression at exhaustion and 24 h (P < 0.05). These results suggest that iHsp72 expression increased in relation to the level of hyperthermia attained and sustained at 60 % and the higher metabolic rate and greater rate of increase in core temperature at 75 %, with the further increase in iHsp72 concentration 24 h after exercise reinforcing its role as a chaperone and cytoprotective agent.

Positive or negative involvement of heat shock proteins in multiple sclerosis pathogenesis: an overview

Multiple sclerosis (MS) is the most diffuse chronic inflammatory disease of the central nervous system. Both immune-mediated and neurodegenerative processes apparently play roles in the pathogenesis of this disease. Heat shock proteins (HSPs) are a family of highly evolutionarily conserved proteins; their expression in the nervous system is induced in a variety of pathologic states, including cerebral ischemia, neurodegenerative diseases, epilepsy, and trauma. To date, investigators have observed protective effects of HSPs in a variety of brain disease models (e.g. of Alzheimer disease and Parkinson disease). In contrast, unequivocal data have been obtained for their roles in MS that depend on the HSP family and particularly on their localization (i.e. intracellular or extracellular). This article reviews our current understanding of the involvement of the principal HSP families in MS.

Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure

Extracellular heat shock protein 72 (eHsp72) concentration increases during exercise-heat stress when conditions elicit physiological strain. Differences in severity of environmental and exercise stimuli have elicited varied response to stress. The present study aimed to quantify the extent of increased eHsp72 with increased exogenous heat stress, and determine related endogenous markers of strain in an exercise-heat model. Ten males cycled for 90 min at 50 % [Formula: see text] in three conditions (TEMP, 20 °C/63 % RH; HOT, 30.2 °C/51%RH; VHOT, 40.0 °C/37%RH). Plasma was analysed for eHsp72 pre, immediately post and 24-h post each trial utilising a commercially available ELISA. Increased eHsp72 concentration was observed post VHOT trial (+172.4 %) (p < 0.05), but not TEMP (-1.9 %) or HOT (+25.7 %) conditions. eHsp72 returned to baseline values within 24 h in all conditions. Changes were observed in rectal temperature (Trec), rate of Trec increase, area under the curve for Trec of 38.5 and 39.0 °C, duration Trec ≥38.5 and ≥39.0 °C, and change in muscle temperature, between VHOT, and TEMP and HOT, but not between TEMP and HOT. Each condition also elicited significantly increasing physiological strain, described by sweat rate, heart rate, physiological strain index, rating of perceived exertion and thermal sensation. Stepwise multiple regression reported rate of Trec increase and change in Trec to be predictors of increased eHsp72 concentration. Data suggests eHsp72 concentration increases once systemic temperature and sympathetic activity exceeds a minimum endogenous criteria elicited during VHOT conditions and is likely to be modulated by large, rapid changes in core temperature.

Muscle heat shock protein 70 predicts insulin resistance with aging

Heat shock protein 70 (HSP70) protects cells from accumulating damaged proteins and age-related functional decline. We studied plasma and skeletal muscle (SkM) HSP70 levels in adult vervet monkeys (life span ≈ 25 years) at baseline and after 4 years (≈10 human years). Insulin, glucose, homeostasis model assessment scores, triglycerides, high-density lipoprotein and total plasma cholesterol, body weight, body mass index, and waist circumference were measured repeatedly, with change over time estimated by individual regression slopes. Low baseline SkM HSP70 was a proximal marker for developing insulin resistance and was seen in monkeys whose insulin and homeostasis model assessment increased more rapidly over time. Changes in SkM HSP70 inversely correlated with insulin and homeostasis model assessment trajectories such that a positive change in SkM level was beneficial. The strength of the relationship between changes in SkM HSP70 and insulin remained unchanged after adjustment for all covariates. Younger monkeys drove these relationships, with HSP70 alone being predictive of insulin changes with aging. Plasma and SkM HSP70 were unrelated and HSP70 release from peripheral blood mononuclear cells was positively associated with insulin concentrations in contrast to SkM. Results from aged humans confirmed this positive association of plasma HSP70 and insulin. In conclusion, higher levels of SkM HSP70 protect against insulin resistance development during healthy aging.

Adrenergic and glucocorticoid modulation of the sterile inflammatory response

Exposure to an intense, acute stressor, in the absence of a pathogen, alters immune function. Exposure to a single bout of inescapable tail shock increases plasma and tissue concentrations of cytokines, chemokines, and the danger associated molecular pattern (DAMP) Hsp72. Although previous studies have demonstrated that adrenergic receptor (ADR) and glucocorticoid receptor (GCR)-mediated pathways alter pathogen or microbial associated molecular pattern (MAMP)-evoked levels of cytokines, chemokines, and Hsp72, far fewer studies have tested the role of these receptors across multiple inflammatory proteins or tissues to elucidate the differences in magnitude of stress-evoked sterile inflammatory responses. The goals of the current study were to (1) compare the sterile inflammatory response in the circulation, liver, spleen, and subcutaneous (SQ) adipose tissue by measuring cytokine, chemokine, and DAMP (Hsp72) responses; and (2) to test the role of alpha-1 (α1), beta-1 (β1), beta-2 (β2), and beta-3 (β3) ADRs, as well as GCRs in signaling the sterile inflammatory response. The data presented indicate plasma and SQ adipose are significantly more stress responsive than the liver and spleen. Further, administration of ADR and GCR-specific antagonists revealed both similarities and differences in the signaling mechanisms of the sterile inflammatory response in the tissues studied. Finally, given the selective increase in the chemokine monocyte chemotactic protein-1 (MCP-1) in SQ tissue, it may be that SQ adipose is an important site of leukocyte migration, possibly in preparation for infection as a consequence of wounding. The current study helps further our understanding of the tissue-specific differences of the stress-induced sterile inflammatory response.

Mutant HSP70 reverses autoimmune depigmentation in vitiligo

Vitiligo is an autoimmune disease characterized by destruction of melanocytes, leaving 0.5% of the population with progressive depigmentation. Current treatments offer limited efficacy. We report that modified inducible heat shock protein 70 (HSP70i) prevents T cell-mediated depigmentation. HSP70i is the molecular link between stress and the resultant immune response. We previously showed that HSP70i induces an inflammatory dendritic cell (DC) phenotype and is necessary for depigmentation in vitiligo mouse models. Here, we observed a similar DC inflammatory phenotype in vitiligo patients. In a mouse model of depigmentation, DNA vaccination with a melanocyte antigen and the carboxyl terminus of HSP70i was sufficient to drive autoimmunity. Mutational analysis of the HSP70i substrate-binding domain established the peptide QPGVLIQVYEG as invaluable for DC activation, and mutant HSP70i could not induce depigmentation. Moreover, mutant HSP70iQ435A bound human DCs and reduced their activation, as well as induced a shift from inflammatory to tolerogenic DCs in mice. HSP70iQ435A-encoding DNA applied months before spontaneous depigmentation prevented vitiligo in mice expressing a transgenic, melanocyte-reactive T cell receptor. Furthermore, use of HSP70iQ435A therapeutically in a different, rapidly depigmenting model after loss of differentiated melanocytes resulted in 76% recovery of pigmentation. Treatment also prevented relevant T cells from populating mouse skin. In addition, ex vivo treatment of human skin averted the disease-related shift from quiescent to effector T cell phenotype. Thus, HSP70iQ435A DNA delivery may offer potent treatment opportunities for vitiligo.

Preferential secretion of inducible HSP70 by vitiligo melanocytes under stress

Inducible HSP70 (HSP70i) chaperones peptides from stressed cells, protecting them from apoptosis. Upon extracellular release, HSP70i serves an adjuvant function, enhancing immune responses to bound peptides. We questioned whether HSP70i differentially protects control and vitiligo melanocytes from stress and subsequent immune responses. We compared expression of HSP70i in skin samples, evaluated the viability of primary vitiligo and control melanocytes exposed to bleaching phenols, and measured secreted HSP70i. We determined whether HSP70i traffics to melanosomes to contact immunogenic proteins by cell fractionation, western blotting, electron microscopy, and confocal microscopy. Viability of vitiligo and control melanocytes was equally affected under stress. However, vitiligo melanocytes secreted increased amounts of HSP70i in response to MBEH, corroborating with aberrant HSP70i expression in patient skin. Intracellular HSP70i colocalized with melanosomes, and more so in response to MBEH in vitiligo melanocytes. Thus, whereas either agent is cytotoxic to melanocytes, MBEH preferentially induces immune responses to melanocytes.

Elevated extracellular HSP70 (HSPA1A) level as an independent prognostic marker of mortality in patients with heart failure

Predicting the survival of a patient with heart failure (HF) is a complex problem in clinical practice. Our previous study reported that extracellular HSP70 (HSPA1A) correlates with markers of heart function and disease severity in HF, but the predictive value of HSP70 is unclear. The goal of this study was to analyze extracellular HSP70 as predictive marker of mortality in HF. One hundred ninety-five patients with systolic heart failure were enrolled and followed up for 60 months. By the end of follow-up, 85 patients were alive (survivors) and 110 died (nonsurvivors). HSP70 (measured by ELISA in the serum) was elevated in nonsurvivors, compared with survivors (0.39 [0.27-0.59] vs. 0.30 [0.24-0.43] ng/ml, respectively, p = 0.0101). In Kaplan-Meier survival analysis higher HSP70 levels above median were associated with a significantly increased mortality. In multivariable survival models, we show that HSP70 level above the median is an age-, sex-, body mass index-, creatinine-, and NT-proBNP-independent predictor of 5-year mortality in HF. Extracellular HSP70 could prove useful for estimating survival in patients with HF.

A protective Hsp70-TLR4 pathway in lethal oxidant lung injury

Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can exacerbate respiratory failure. Our previous study showed that TLR4 confers protection against hyperoxia-induced lung injury and mortality. Hsp70 has potent cytoprotective properties and has been described as a TLR4 ligand in cell lines. We sought to elucidate the relationship between TLR4 and Hsp70 in hyperoxia-induced lung injury in vitro and in vivo and to define the signaling mechanisms involved. Wild-type, TLR4(-/-), and Trif(-/-) (a TLR4 adapter protein) murine lung endothelial cells (MLECs) were exposed to hyperoxia. We found markedly elevated levels of intracellular and secreted Hsp70 from wild-type mice lungs and MLECs after hyperoxia. We confirmed that Hsp70 and TLR4 coimmunoprecipitate in lung tissue and MLECs. Hsp70-mediated NF-κB activation appears to depend upon TLR4. In the absence of TLR4, Hsp70 loses its protective effects in endothelial cells. Furthermore, these protective properties of Hsp70 are TLR4 adapter Trif dependent and MyD88 independent. Hsp70-deficient mice have increased mortality during hyperoxia, and lung-targeted adenoviral delivery of Hsp70 effectively rescues both Hsp70-deficient and wild-type mice. To our knowledge, our studies are the first to define an Hsp70-TLR4-Trif cytoprotective axis in the lung and endothelial cells. This pathway is a potential therapeutic target against a range of oxidant-induced lung injuries.

Persistently elevated extracellular HSP70 (HSPA1A) level as an independent prognostic marker in post-cardiac-arrest patients

Predicting the prognosis of comatose, post-cardiac-arrest patients is a complex problem in clinical practice. There are several established methods to foretell neurological outcome; however, further prognostic markers are needed. HSP70 (HSPA1A), which increases rapidly in response to severe stress (among others after ischemic or hypoxic events), is a biomarker of cell damage in the ischemic brain and spinal cord. We hypothesized that HSP70 might be a reliable predictor of mortality in post-cardiac-arrest patients. The aim of this study was to analyze the role of extracellular HSP70 in the systemic inflammatory response over time, as well as the predictive value in cardiac arrest patients. Here, we show that the elevation of HSP70 levels in resuscitated patients and their persistence is an independent predictor of 30-day mortality after a cardiac arrest. Forty-six cardiac arrest patients were successfully cooled to 32-34 °C for 24 h, and followed up for 30 days. Twenty-four patients (52.2 %) were alive by the end of follow-up, and 22 patients (47.8 %) died. Forty-six patients with stable cardiovascular disease served as controls. Extracellular HSP70 (measured by ELISA in blood samples) was elevated in all resuscitated patients (1.31 [0.76-2.73] and 1.70 [1.20-2.37] ng/ml for survivors and non-survivors, respectively), compared with the controls (0.59 [0.44-0.83] ng/ml). HSP70 level decreased significantly in survivors, but persisted in non-survivors, and predicted 30-day mortality regardless of age, sex, complications, and the APACHE II score. Extracellular HSP70 could prove useful for estimating prognosis in comatose post-cardiac-arrest patients.

Azacytidine induces necrosis of multiple myeloma cells through oxidative stress

Azacytidine is an inhibitor of DNA methyltransferase and is known to be an anti-leukemic agent to induce cancer cell apoptosis. In the present study, multiple myeloma cells were treated with azacytidine at clinically relevant concentrations to induce necrosis through oxidative stress. Necrotic myeloma cells exhibit unique characteristics, including enrichment of the cell-bound albumin and overexpression of endoplasmic reticulum (ER)- and mitochondrial-specific chaperones, which were not observed in other necrotic cells, including HUH-7, A2780, A549, and Hoc1a. Proteomic analysis shows that HSP60 is the most abundant up-regulated mitochondrial specific chaperone, and azacytidine-induced overexpression of HSP60 is confirmed by western blot analysis. In contrast, expression levels of cytosolic chaperones such as HSP90 and HSP71 were down-regulated in azacytidine-treated myeloma cells, concomitant with an increase of these chaperones in the cell culture medium, suggesting that mitochondrial chaperones and cytosolic chaperones behave differently in necrotic myeloma cells; ER- and mitochondrial-chaperones being retained, and cytosolic chaperones being released into the cell culture medium through the ruptured cell membrane. Our data suggest that HSP60 is potentially a new target for multiple myeloma chemotherapy.

Loss of the inducible Hsp70 delays the inflammatory response to skeletal muscle injury and severely impairs muscle regeneration

Skeletal muscle regeneration following injury is a highly coordinated process that involves transient muscle inflammation, removal of necrotic cellular debris and subsequent replacement of damaged myofibers through secondary myogenesis. However, the molecular mechanisms which coordinate these events are only beginning to be defined. In the current study we demonstrate that Heat shock protein 70 (Hsp70) is increased following muscle injury, and is necessary for the normal sequence of events following severe injury induced by cardiotoxin, and physiological injury induced by modified muscle use. Indeed, Hsp70 ablated mice showed a significantly delayed inflammatory response to muscle injury induced by cardiotoxin, with nearly undetected levels of both neutrophil and macrophage markers 24 hours post-injury. At later time points, Hsp70 ablated mice showed sustained muscle inflammation and necrosis, calcium deposition and impaired fiber regeneration that persisted several weeks post-injury. Through rescue experiments reintroducing Hsp70 intracellular expression plasmids into muscles of Hsp70 ablated mice either prior to injury or post-injury, we confirm that Hsp70 optimally promotes muscle regeneration when expressed during both the inflammatory phase that predominates in the first four days following severe injury and the regenerative phase that predominates thereafter. Additional rescue experiments reintroducing Hsp70 protein into the extracellular microenvironment of injured muscles at the onset of injury provides further evidence that Hsp70 released from damaged muscle may drive the early inflammatory response to injury. Importantly, following induction of physiological injury through muscle reloading following a period of muscle disuse, reduced inflammation in 3-day reloaded muscles of Hsp70 ablated mice was associated with preservation of myofibers, and increased muscle force production at later time points compared to WT. Collectively our findings indicate that depending on the nature and severity of muscle injury, therapeutics which differentially target both intracellular and extracellular localized Hsp70 may optimally preserve muscle tissue and promote muscle functional recovery.

Oxidative stress induces monocyte necrosis with enrichment of cell-bound albumin and overexpression of endoplasmic reticulum and mitochondrial chaperones

In the present study, monocytes were treated with 5-azacytidine (azacytidine), gossypol or hydrogen peroxide to induce cell death through oxidative stress. A shift from apoptotic to necrotic cell death occurred when monocytes were treated with 100 µM azacytidine for more than 12 hours. Necrotic monocytes exhibited characteristics, including enrichment of cell-bound albumin and up-regulation of endoplasmic reticulum (ER)- and mitochondrial-specific chaperones to protect mitochondrial integrity, which were not observed in other necrotic cells, including HUH-7, A2780, A549 and HOC1a. Our results show that the cell-bound albumin originates in the culture medium rather than from monocyte-derived hepatocytes, and that HSP60 is a potential binding partner of the cell-bound albumin. Proteomic analysis shows that HSP60 and protein disulfide isomerase are the most abundant up-regulated mitochondrial and ER-chaperones, and that both HSP60 and calreticulin are ubiquitinated in necrotic monocytes. In contrast, expression levels of the cytosolic chaperones HSP90 and HSP71 were down-regulated in the azacytidine-treated monocytes, concomitant with an increase in the levels of these chaperones in the cell culture medium. Collectively, our results demonstrates that chaperones from different organelles behave differently in necrotic monocytes, ER- and mitochondrial chaperones being retained and cytosolic and nuclear chaperones being released into the cell culture medium through the ruptured cell membrane. HSP60 may serve as a new target for development of myeloid leukemia treatment.

The interaction of HspA1A with TLR2 and TLR4 in the response of neutrophils induced by ovarian cancer cells in vitro

Inducible heat shock protein (HspA1A) promotes tumor cell growth and survival. It also interacts with effector cells of the innate immune system and affects their activity. Recently, we showed that the direct contact of ovarian cancer cells, isolated from tumor specimens, with neutrophils intensified their biological functions. Our current experiments demonstrate that the activation of neutrophils, followed by an increased production of reactive oxygen species, by cancer cells involves the interaction of HspA1A from cancer cells with Toll-like receptors 2 and 4 expressed on the neutrophils' surface. Our data may have a practical implication for targeted anticancer therapies based, among other factors, on the inhibition of HspA1A expression in the cancer cells.

HSP70 increases extracellular matrix production by human vascular smooth muscle through TGF-β1 up-regulation

The circulating levels of heat shock proteins (HSP) are increased in cardiovascular diseases; however, the implication of this for the fibrotic process typical of such diseases remains unclear. HSP70 can interact with the vascular smooth muscle cells (SMC), the major producer of extracellular matrix (ECM) proteins, through the Toll-like receptors 4 (TLR4). The transforming growth factor type-β1 (TGF-β1) is a well known vascular pro-fibrotic cytokine that is regulated in part by AP-1-dependent transcriptional mechanisms. We hypothesized that extracellular HSP70 could interact with SMCs, inducing TGF-β1 synthesis and subsequent changes in the vascular ECM. We demonstrate that extracellular HSP70 binds to human aorta SMC TLR4, which up-regulates the AP-1-dependent transcriptional activity of the TGF-β1 promoter. This is achieved through the mitogen activated protein kinases JNK and ERK, as demonstrated by the use of specific blockers and the knockdown of TLR4 with specific small interfering RNAs. The TGF-β1 upregulation increase the expression of the ECM proteins type I collagen and fibronectin. This novel observation may elucidate the mechanisms by which HSP70 contributes in the inflammation and fibrosis present in atherosclerosis and other fibrosis-related diseases.

Delayed temporal increase of hepatic Hsp70 in ApoE knockout mice after prenatal arsenic exposure

Prenatal arsenic exposure accelerates atherosclerosis in ApoE(-/-) mice by unknown mechanism. Arsenic is a hepatotoxicant, and liver disease increases atherosclerosis risk. Prenatal arsenic exposure may predispose to liver disease by priming for susceptibility to other environmental insults. Earlier microarray analyses showed prenatal arsenic exposure increased Hsc70 (HspA8) and Hsp70 (HspA1a) mRNAs in livers of 10-week-old mice. We determined effects of prenatal arsenic exposure on hepatic Hsp70 and Hsc70 expression by Western blot and on DNA methylation by methyl acceptance assay during prenatal and postnatal development. Pregnant ApoE(-/-) mice were given drinking water containing 85 mg/l NaAsO(2) (49 ppm arsenic) from gestation day (GD) 8 to 18. Hsp70 and Hsc70 expression and DNA methylation were determined in GD18 fetuses and 3-, 10-, and 24-week-old mice. Hsc70 expression was unchanged at all ages. Hsp70 induction was observed at 3 and 10 weeks, but was unchanged in GD18 fetuses and 24-week livers of mice. Global DNA methylation increased with age; arsenic had no effects. Bisulfite sequencing of DNA from livers of 10-week-old mice showed Hsp70 promoter region methylation was unchanged, but methylation was increased within the transcribed region. Hsf1 and Nrf2 nuclear translocation were investigated as potential mechanisms of Hsp70 induction and found unaltered. Putative binding sites were identified in HSP70 for in utero arsenic exposure-suppressed microRNAs suggesting a possible mechanism. Thus, prenatal arsenic exposure causes delayed temporal hepatic Hsp70 induction, suggesting a transient state of stress in livers which can predispose the mice to developing liver disease.

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.

Effect of moxibustion pretreatment on serum levels of Helicobacter pylori IgG and eHSP72 in rats with Helicobacter pylori-induced gastritis

AIM: To investigate the effect of moxibustion pretreatment on serum levels of Helicobacter pylori (H. pylori) IgG and extracellular heat shock protein 72 (eHSP72) in rats with H. pylori-induced gastritis.

METHODS: Fifty healthy rats were randomly divided into five groups: A (normal controls), B (infected with H. pylori), C (moxibustion at acupoints), D (moxibustion at non-acupoints), and E (electroacupuncture at acupoints). Gastritis was induced in rats by oral gavage with H. pylori. The levels of serum H. pylori IgG and eHSP72 were measured by enzyme-linked immunosorbent assay.

RESULTS: Compared to group A, the ulcer index and serum levels of H. pylori IgG and eHSP72 significantly increased in group B (0.50 ± 1.00 vs 6.50 ± 4.75, 76.72 μg/L ± 11.02 μg/L vs 131.91 μg/L ± 30.04 μg/L, 152.2 ng/L ± 22.72 ng/L vs

222.59 ng/L ± 56.69 ng/L, all P < 0.01). Compared to group B, the UI and serum levels of H. pylori IgG significantly decreased (6.50 ± 4.75 vs 1.00 ± 2.00, 131.91 μg/L ± 30.04 μg/L vs 86.25 μg/L ± 18.63 μg/L, both P < 0.01) and serum levels of eHSP72 significantly increased in group C (222.59 ng/L ± 56.69 ng/L vs 285.54 ng/L ± 68.23 ng/L, P < 0.05). Compared to group D, the UI and serum levels of H. pylori IgG significantly decreased (3.00 ± 5.00 vs 1.00 ± 2.00, 116.19 μg/L ± 31.25 μg/L vs 86.25 μg/L ± 18.63 μg/L, both P < 0.01) and serum levels of eHSP72 significantly increased in group C (185.97 ng/L ± 77.62 ng/L vs 285.54 ng/L ± 68.23 ng/L, P < 0.01). Compared to group E, serum levels of H. pylori IgG significantly decreased in group C (120.25 μg/L ± 25.40 μg/L vs 86.25 μg/L ± 18.63 μg/L, P < 0.01).

CONCLUSION: Moxibustion at acupoints reduces H. pylori-induced gastric mucosal injury possibly via mechanisms associated with increasing serum levels of eHSP72.

Involvement of extracellular Hsp72 in wear particle-mediated osteolysis

Wear particle-mediated osteolysis is one of the major problems affecting long-term survival of orthopaedic prostheses, frequently progressing to failure of fixation and revision surgery. Upon challenging with wear particles, macrophages and various other types of cells release soluble factors that stimulate the resorptive activity of osteoclasts and impair the function and activity of osteoblasts. Extracellular Hsp72 has been reported to activate macrophages and up-regulate pro-inflammatory cytokine production, although its role in osteolysis has not been established yet. The purpose of our study was to evaluate the involvement of this protein in the inflammatory response to wear particles that leads to periprosthetic osteolysis. To this end, we used interfacial tissues and blood samples from patients undergoing revision surgery due to aseptic loosening of cementless acetabular cups. Confocal microscopy indicated that Hsp72 co-localises with CD14(+) cells of interfacial tissues. Levels of Hsp72 in the culture media from periprosthetic membranes cultured ex vivo decreased along culture time and Hsp72 levels in sera from patients were lower and under the assay detection limit compared with those from age-matched control subjects. This suggests that interfacial tissues are not actively producing the protein but likely recruit it from peripheral circulation. Incubation of human macrophages with titanium (Ti) particles decreased the release of Hsp72 into culture media. Treatment with recombinant human Hsp72 enhanced considerably IL-6 levels in culture media which were not modified after macrophage co-stimulation with Ti particles, while pre-incubation with Hsp72 increased the Ti particle-induced TNF-α and IL-1β production. Altogether, these data indicate that extracellular Hsp72 amplifies the inflammatory response to wear debris by interacting with resident macrophages in periprosthetic tissues.

Combined microwave irradiation and intraarticular glutamine administration-induced HSP70 expression therapy prevents cartilage degradation in a rat osteoarthritis model

The objective of the present study was to investigate the effects of heat stimulation and glutamine (Gln) on the expression of extracellular matrix genes and heat shock protein 70 (HSP70) in rat articular cartilage in vivo and to determine whether HSP70 expression achieved with a combination of microwave (MW) and Gln suppresses osteoarthritis (OA) progression in a rat OA model. Stimulation at 40 W was assumed to be appropriate in the present study, and the effects of heat treatment at this intensity were evaluated. Articular cartilage was collected at 8 h after heat stimulation and/or intraarticular Gln administration, and total RNA was extracted. The expression of HSP70, aggrecan, and type II collagen was quantified using real-time RT-PCR. Cartilage samples from the OA model were subjected to hematoxylin and eosin (HE) and safranin O staining. HSP70 and aggrecan expression was greatest in a group receiving both MW and Gln. In the rat OA model, the severity of OA was significantly milder in a group receiving MW and Gln than in the control group. HSP70, stimulated by the combination of MW heat and Gln, may be involved in the suppression of OA progression.

HSP70i is a critical component of the immune response leading to vitiligo

HSP70i and other stress proteins have been used in anti-tumor vaccines. This begs the question whether HSP70i plays a unique role in immune activation. We vaccinated inducible HSP70i (Hsp70-1) knockout mice and wild-type animals with optimized TRP-1, a highly immunogenic melanosomal target molecule. We were unable to induce robust and lasting depigmentation in the Hsp70-1 knockout mice, and in vivo cytolytic assays revealed a lack of cytotoxic T-lymphocyte activity. Absence of T-cell infiltration to the skin and maintenance of hair follicle melanocytes were observed. By contrast, depigmentation proceeded without interruption in mice lacking a tissue-specific constitutive isoform of HSP70 (Hsp70-2) vaccinated with TRP-2. Next, we demonstrated that HSP70i was necessary and sufficient to accelerate depigmentation in vitiligo-prone Pmel-1 mice, accompanied by lasting phenotypic changes in dendritic cell subpopulations. In summary, these studies assign a unique function to HSP70i in vitiligo and identify HSP70i as a targetable entity for treatment.

Molecular chaperones and heat shock proteins in atherosclerosis

In response to stress stimuli, mammalian cells activate an ancient signaling pathway leading to the transient expression of heat shock proteins (HSPs). HSPs are a family of proteins serving as molecular chaperones that prevent the formation of nonspecific protein aggregates and assist proteins in the acquisition of their native structures. Physiologically, HSPs play a protective role in the homeostasis of the vessel wall but have an impact on immunoinflammatory processes in pathological conditions involved in the development of atherosclerosis. For instance, some members of HSPs have been shown to have immunoregulatory properties and modification of innate and adaptive response to HSPs, and can protect the vessel wall from the disease. On the other hand, a high degree of sequence homology between microbial and mammalian HSPs, due to evolutionary conservation, carries a risk of misdirected autoimmunity against HSPs expressed on the stressed cells of vascular endothelium. Furthermore, HSPs and anti-HSP antibodies have been shown to elicit production of proinflammatory cytokines. Potential therapeutic use of HSP in prevention of atherosclerosis involves achieving optimal balance between protective and immunogenic effects of HSPs and in the progress of research on vaccination. In this review, we update the progress of studies on HSPs and the integrity of the vessel wall, discuss the mechanism by which HSPs exert their role in the disease development, and highlight the potential clinic translation in the research field.

Increased heat shock protein 70 levels in induced sputum and plasma correlate with severity of asthma patients

Damage-associated molecular pattern molecules such as high-mobility group box 1 protein (HMGB1) and heat shock protein 70 (HSP70) have been implicated in the pathogenesis of asthma. The aim of our study was to examine the induced sputum and plasma concentrations of HSP70 in asthmatic patients to determine their relationship with airway obstruction. Thirty-four healthy controls and 56 patients with persistent bronchial asthma matched for gender and age were enrolled in this study. Spirometry measurements were performed before sputum induction. HSP70 levels in induced sputum and plasma were measured using the ELISA Kit. Sputum and plasma concentrations of HSP70 in asthmatics patients were significantly higher than that in control subjects (sputum, (0.88 ng/ml (0.27-1.88 ng/ml) versus 0.42 ng/ml (0.18-0.85 ng/ml), p < 0.001); plasma, (0.46 ng/ml (0.20-0.98 ng/ml) versus 0.14 ng/ml (0.11-0.37 ng/ml), p < 0.001) and were significantly negatively correlated with forced expiratory volume in 1 s (FEV1), FEV1 (percent predicted), and FEV1/FVC in all 90 participants and 56 patients with asthma. There were no significant differences in HSP70 levels between patients with eosinophilic and non-eosinophilic asthma. HSP70 levels in plasma were positively correlated with neutrophil count, and HSP70 levels in induced sputum were positively correlated with lymphocyte count. In multivariate analysis, independent predictors of sputum HSP70 were diseases and disease severity but not smoking, age, or gender, and independent predictors of plasma HSP70 were also diseases and disease severity. In conclusion, this study indicates that induced sputum and plasma HSP70 could serve as a useful marker for assessing the degree of airway obstruction in patients with asthma. However, further investigation is needed to establish the role of circulating and sputum HSP70 in the pathogenesis of asthma.

Serum heat shock protein 70 levels, oxidant status, and mortality in sepsis

Animal studies as well as prospective randomized clinical trials associated sepsis with redox imbalance and oxidative stress, but other studies failed to establish a correlation between antioxidant-based therapies and improvement of sepsis condition. This is also true for studies on the role of the chaperone heat shock protein 70 (HSP70), which is increased in serum during sepsis. Heat shock protein 70 is affected at several levels by oxidative stress, but this relationship has never been studied in sepsis. Here, we evaluated the relationship between serum HSP70 immunocontent and oxidant status in sepsis. Patients with severe sepsis were followed up for 28 days after diagnosis, or until death. Up to a maximum of 12 h after sepsis diagnosis, serum was collected for determination of HSP70 immunocontent by Western blot and evaluation of oxidative parameters (TRAP [total radical-trapping antioxidant parameter], TBARSs [thiobarbituric acid-reactive substances], and carbonyl levels). Serum of sepsis patients presented enhanced HSP70 levels. Analysis of oxidative parameters revealed that septic patients with pronounced oxidative damage in serum had also increased HSP70 serum levels. Sepsis patients in whom serum oxidative stress markers were not different from control presented normal serum HSP70. Analysis of septic patients according to survival outcome also indicated that patients with increased HSP70 serum levels presented increased mortality. We concluded that serum HSP70 levels are modulated according to the patient oxidant status, and increased serum HSP70 is associated to mortality in sepsis.

Modulatory role of calreticulin as chaperokine for dendritic cell-based immunotherapy

Heat shock proteins (HSPs) play a regulatory role for maturation of antigen-presenting cells (APCs) such as dendritic cells (DCs) and macrophages. Whereas HSP70 has been shown to enhance the maturation of human DCs via a nuclear factor kappa-B (NF-κB)-dependent pathway, the regulatory role of calreticulin (CRT), which is a HSP with similar functions to HSP70, is not well studied. To investigate the role of CRT as adjuvant in cell activation and co-stimulatory responses we determined the effects of CRT on human APC maturation in comparison to that of HSP70. To facilitate eukaryotic endotoxin-free CRT protein expression, three different methods were compared. We demonstrate that CRT induces the maturation of human DCs and increases the production of proinflammatory cytokines via the NF-κB pathway. CRT-mediated maturation was qualitatively similar to that induced by HSP70. Interestingly, priming of monocytes with HSPs showed an even more prominent effect on maturation than exposure of immature DCs to these compounds. A higher expression of CD86, CD83 and CCR7 on mature DCs were found in response to CRT. Our data provide novel insights into the role of extracellular HSPs as chaperokines in the processes of APC generation and may thus be useful to improve adoptive immunotherapy.

Heat shock proteins as biomarkers for the rapid detection of brain and spinal cord ischemia: a review and comparison to other methods of detection in thoracic aneurysm repair

The heat shock proteins (HSPs) are members of highly conserved families of molecular chaperones that have multiple roles in vivo. We discuss the HSPs in general, and Hsp70 and Hsp27 in particular, and their rapid induction by severe stress in the context of tissue and organ expression in physiology and disease. We describe the current state of knowledge of the relationship and interactions between extra- and intracellular HSPs and describe mechanisms and significance of extracellular expression of HSPs. We focus on the role of the heat shock proteins as biomarkers of central nervous system (CNS) ischemia and other severe stressors and discuss recent and novel technologies for rapid measurement of proteins in vivo and ex vivo. The HSPs are compared to other proposed small molecule biomarkers for detection of CNS injury and to other methods of detecting brain and spinal cord ischemia in real time. While other biomarkers may be of use in prognosis and in design of appropriate therapies, none appears to be as rapid as the HSPs; therefore, no other measurement appears to be of use in the immediate detection of ongoing severe ischemia with the intention to immediately intervene to reduce the severity or risk of permanent damage.

Hsp70: anti-apoptotic and tumorigenic protein

Heat shock protein 70 (Hsp70) is a powerful chaperone whose expression is induced in response to a wide variety of physiological and environmental insults, including anticancer chemotherapy, thus allowing the cell to survive to lethal conditions. Hsp70 cytoprotective properties may be explained by its anti-apoptotic function. Indeed, this protein can inhibit key effectors of the apoptotic machinery at the pre- and postmitochondrial level. In cancer cells, the expression of Hsp70 is abnormally high, and Hsp70 may participate in oncogenesis and in resistance to chemotherapy. In rodent models, Hsp70 overexpression increases tumor growth and metastatic potential. Depletion or inhibition of Hsp70 frequently reduces the size of the tumors and even can cause their complete involution. But Hsp70 can also be found in the extracellular medium. Its role is then immunogenic and the term chaperokine to define the extracellular chaperones has been advanced. Hsp70 tumorigenic functions as well as the strategies that are being developed in cancer therapy in order to inhibit Hsp70 are commented in this chapter.

The Hsp72 response in peri-parturient dairy cows: relationships with metabolic and immunological parameters

The study was aimed at assessing whether the peri-parturient period is associated with changes of intracellular and plasma inducible heat shock proteins (Hsp) 72 kDa molecular weight in dairy cows, and to establish possible relationships between Hsp72, metabolic, and immunological parameters subjected to changes around calving. The study was carried out on 35 healthy peri-parturient Holstein cows. Three, two, and one week before the expected calving, and 1, 2, 3, 4, and 5 weeks after calving, body conditions score (BCS) was measured and blood samples were collected to separate plasma and peripheral blood mononuclear cells (PBMC). Concentrations of Hsp72 in PBMC and plasma increased sharply after calving. In the post-calving period, BCS and plasma glucose declined, whereas plasma nonesterified fatty acids (NEFA) and tumor necrosis factor-alpha increased. The proliferative responses of PBMC to lipopolysaccharide (LPS) declined progressively after calving. The percentage of PBMC expressing CD14 receptors and Toll-like receptors (TLR)-4 increased and decreased in the early postpartum period, respectively. Correlation analysis revealed significant positive relationships between Hsp72 and NEFA, and between PBMC proliferation in response to LPS and the percentage of PBMC expressing TLR-4. Conversely, significant negative relationships were found between LPS-triggered proliferation of PBMC and both intracellular and plasma Hsp72. Literature data and changes of metabolic and immunological parameters reported herein authorize a few interpretative hypotheses and encourage further studies aimed at assessing possible cause and effect relationships between changes of PBMC and circulating Hsp72, metabolic, and immune parameters in dairy cows.

Toll-like receptors 2 and 4: initiators of non-septic inflammation in critical care medicine?

PURPOSE

Although the role of Toll-like receptors (TLRs) in bacterial infection and sepsis is well characterized, recent studies have also shown that TLR4 and TLR2 can play an important role in contributing to acute inflammatory processes and organ dysfunction in settings in which LPS or other bacterial products are not present. This review presents not only insights into pathophysiologic mechanisms that contribute to organ dysfunction and outcome in critical illness, but also direct therapeutic approaches to ameliorating such TLR-mediated responses that may potentially be of clinical benefit in critically ill patients.

METHOD

Literature review of the role of TLR4 and TLR2 in sterile inflammation relevant to critical care medicine using PubMed search, including original papers in English from 1990 to 2010.

CONCLUSION

There is increasing evidence that TLR4 and TLR2 are not only receptors for bacterial products, but also can be activated through other mechanisms relevant to the pathophysiology of critical illnesses. There is evidence that TLR4 and TLR2 are involved in ischemia-reperfusion injury and trauma where Gram-negative or Gram-positive bacteria are not detectible in the circulation or local organ sites, such as the lungs. In these settings TLRs can transduce other proinflammatory signals and thereby contribute to cellular activation leading to acute lung injury and other organ system dysfunction. The consequences of TLR4 and TLR2 activation through reactive oxygen species (ROS), heat shock proteins, and other non-LPS dependent mechanisms may be different from those associated with binding of the membrane component of bacteria to TLR4 or TLR2 and may produce different signatures of gene activation and release of proinflammatory mediators.