Heat Shock Proteins in Vascular Disease—A Review

Newcastle disease virus regulates its replication by instigating oxidative stress-driven Sirtuin 7 production

Reactive oxygen species (ROS) accumulation inside the cells instigates oxidative stress, activating stress-responsive genes. The viral strategies for promoting stressful conditions and utilizing the induced host proteins to enhance their replication remain elusive. The present work investigates the impact of oxidative stress responses on Newcastle disease virus (NDV) pathogenesis. Here, we show that the progression of NDV infection varies with intracellular ROS levels. Additionally, the results demonstrate that NDV infection modulates the expression of oxidative stress-responsive genes, majorly sirtuin 7 (SIRT7), a NAD+-dependent deacetylase. The modulation of SIRT7 protein, both through overexpression and knockdown, significantly impacts the replication dynamics of NDV in DF-1 cells. The activation of SIRT7 is found to be associated with the positive regulation of cellular protein deacetylation. Lastly, the results suggested that NDV-driven SIRT7 alters NAD+ metabolism in vitro and in ovo. We concluded that the elevated expression of NDV-mediated SIRT7 protein with enhanced activity metabolizes the NAD+ to deacetylase the host proteins, thus contributing to high virus replication.

The Role of Extracellular Heat Shock Proteins in Cardiovascular Diseases

In the early 1960s, heat shock proteins (HSPs) were first identified as vital intracellular proteinaceous components that help in stress physiology and reprogram the cellular responses to enable the organism's survival. By the early 1990s, HSPs were detected in extracellular spaces and found to activate gamma-delta T-lymphocytes. Subsequent investigations identified their association with varied disease conditions, including autoimmune disorders, diabetes, cancer, hepatic, pancreatic, and renal disorders, and cachexia. In cardiology, extracellular HSPs play a definite, but still unclear, role in atherosclerosis, acute coronary syndromes, and heart failure. The possibility of HSP-targeted novel molecular therapeutics has generated much interest and hope in recent years. In this review, we discuss the role of Extracellular Heat Shock Proteins (Ec-HSPs) in various disease states, with a particular focus on cardiovascular diseases.

Aspirin relieves the calcification of aortic smooth muscle cells by enhancing the heat shock response

CONTEXT

Vascular calcification is a major complication of chronic renal failure, which has been identified as an active process partly driven by osteogenic transition of vascular smooth muscle cells (VSMCs). Aspirin could prevent cardiomyocyte damage by inducing heat shock response.

OBJECTIVE

This study investigates the effect of aspirin on alleviating VSMC calcification.

MATERIALS AND METHODS

An in vitro VSMC calcification model was established by 10-day calcification induction in osteogenic medium. VSMCs were grouped as following: control group (normal medium), calcified group (osteogenic medium) and treated group (osteogenic medium with 1 or 4 mmol/L aspirin). VSMC calcification was evaluated by calcified nodules formation, intracellular calcium concentration and osteoblastic marker (OPN and Runx2) expression.

RESULTS

After 10-day culture, the intracellular calcium concentration in calcified group was significantly higher than that in control group (1.16 ± 0.04 vs. 0.14 ± 0.01 μg/mg, p < 0.01), but significantly reduced in 1 mmol/L aspirin treated group (0.74 ± 0.05 μg/mg, p < 0.01), and 4 mmol/L aspirin treated group (0.93 ± 0.03 μg/mg, p < 0.01). The elevated expression of OPN and Runx2 induced by osteogenic medium was significantly relieved after 1 or 4 mmol/L aspirin treatment. The expression of HSF1, HSP70 and HSP90 was decreased in calcification-induced VSMCs, but significantly increased after treatment of aspirin. Furthermore, inhibition of HSP70 (or HSP90) by small-molecule inhibitor or small interfering RNA could partially abolish the anti-calcification effect of aspirin, proved by the changes of intracellular calcium concentration and osteoblastic marker expression.

DISCUSSION AND CONCLUSIONS

Aspirin could relieve the calcification of VSMCs partially through HSP70- or HSP90-mediated heat shock response. These findings expanded the understanding of aspirin pharmacology, and imply that local induction expression of HSPs might be a potential therapeutic strategy for the prevention and therapy of vascular calcification.

Heat shock proteins: Biological functions, pathological roles, and therapeutic opportunities

The heat shock proteins (HSPs) are ubiquitous and conserved protein families in both prokaryotic and eukaryotic organisms, and they maintain cellular proteostasis and protect cells from stresses. HSP protein families are classified based on their molecular weights, mainly including large HSPs, HSP90, HSP70, HSP60, HSP40, and small HSPs. They function as molecular chaperons in cells and work as an integrated network, participating in the folding of newly synthesized polypeptides, refolding metastable proteins, protein complex assembly, dissociating protein aggregate dissociation, and the degradation of misfolded proteins. In addition to their chaperone functions, they also play important roles in cell signaling transduction, cell cycle, and apoptosis regulation. Therefore, malfunction of HSPs is related with many diseases, including cancers, neurodegeneration, and other diseases. In this review, we describe the current understandings about the molecular mechanisms of the major HSP families including HSP90/HSP70/HSP60/HSP110 and small HSPs, how the HSPs keep the protein proteostasis and response to stresses, and we also discuss their roles in diseases and the recent exploration of HSP related therapy and diagnosis to modulate diseases. These research advances offer new prospects of HSPs as potential targets for therapeutic intervention.

Toll-like Receptor 4 Signaling is Critical for the Adaptive Cellular Stress Response Effects Induced by Intermittent Fasting in the Mouse Brain

Among different kinds of dietary energy restriction, intermittent fasting (IF) has been considered a dietary regimen which causes a mild stress to the organism. IF can stimulate proteins and signaling pathways related to cell stress that can culminate in the increase of the body resistance to severe stress conditions. Energy intake reduction induced by IF can induce modulation of receptors, kinases, and phosphatases, which in turn can modulate the activation of transcription factors such as NF-E2-related factor 2 (NRF2) and cAMP response element-binding (CREB) which regulate the transcription of genes related to the translation of proteins such as growth factors: brain-derived neurotrophic factor (BDNF), chaperone proteins: heat shock proteins (HSP), and so on. It has been shown that toll-like receptors (TLRs) are important molecules in innate immune response which are present not only in the periphery but also in neurons and glial cells. In central nervous system, TLRs can exert functions related to set up responses to infection, as well as influence neural progenitor cell proliferation and differentiation, being involved in cognitive parameters such as learning and memory. Little is known about the involvement of TLR4 on the beneficial effects induced by IF protocol. The present work investigated the effects of IF on memory and on the signaling mechanisms associated with NRF2 and CREB in Tlr4 knockout mice. The results suggest that TLR4 participates in the modulatory effects of IF on oxidative stress levels, on the transcription factors CREB and NRF2, and on BDNF and HSP90 expressions in hippocampus.

Modulatory effects of curcumin on heat shock proteins in cancer: A promising therapeutic approach

Cancer metastasis represents a multistep process, including alteration of cell adhesion/motility in the microenvironment and sustained angiogenesis, which is essential for supporting cancer growth in tissues that are distant from the primary tumor. There is growing evidence suggesting that heat shock proteins (HSPs) (also known as heat stress proteins), which constitute a family of stress-inducible proteins, may be involved in the pathogenesis of cancer. Curcumin (diferuloylmethane) is a potent anti-inflammatory, antioxidant, antimicrobial, and antitumor agent. Curcumin has been shown to regulate different members of HSPs including HSP27, HSP40, HSP60, HSP70, and HSP90 in cancer. Here, we present extent findings suggesting that curcumin may act as a potential therapeutic agent for the treatment of cancer through its regulation of HSPs.

Vitamin D supplementation and serum heat shock protein 60 levels in patients with coronary heart disease: a randomized clinical trial

BACKGROUND

The aim in this study was to investigate the effect of vitamin D (25(OH)D3) supplementation on heat shock protein 60 (HSP 60) and other inflammatory markers (IL-17, TNF-α, PAB) in patients with coronary heart disease (CHD).

METHODS

In this double-blind, randomized clinical trial, we recruited 80 male and female patients aged 30-60 with CHD and 25(OH)D3 serum levels < 30 ng/ml from Rasool-e-Akram Hospital in Tehran, Iran. Serum levels of HSP 60 as primary outcome, and 25(OH)D3, IL-17, TNF-α, PAB, lipid profiles and parathyroid hormone (PTH) as secondary outcomes were measured at baseline and post-intervention. We randomly assigned eligible participants to a placebo group (N = 40) or an intervention group (N = 40) (50,000 IU/wk. vitamin D supplement) for eight weeks.

RESULTS

The results demonstrated that vitamin D supplementation resulted in a significant increase in 25(OH) D3 serum levels in the intervention group compared to the placebo group (46.86 vs. 7.28 ng/ml). PTH levels decreased in the intervention group compared to the placebo group (- 19.81 vs. 2.92 pg/ml) after eight weeks of supplementation. Furthermore, we observed a significant change in waist circumference (- 0.97 vs. -0.26 cm), fat percentage (-.13 vs. 0.1%), systolic blood pressure (- 3.85 vs. -2.11 mmHg) and diastolic blood presure (- 4 vs. -1.86 mmHg) in the vitamin D group compared to the placebo group (all P values < 0.05). Other variables did not significantly change after the intervention.

CONCLUSION

Based on our findings, weekly vitamin D supplementation of 50,000 IU for eight weeks in patients with CHD resulted in decreased systolic and diastolic blood pressure, waist circumference and fat percentage. No significant effect on HSP 60, inflammatory markers or lipid profiles was observed.

TRIAL REGISTRATION

IRCT, IRCT201612122365N14. Registered 12 December 2016.

Comparative genomic analysis of Myroides odoratimimus isolates

Myroides odoratimimus is an important nosocomial pathogen. Management of M. odoratimimus infection is difficult owing to the multidrug resistance and the unknown pathogenesis mechanisms. Based on our previous genomic sequencing data of M. odoratimimus PR63039 (isolated from a patient with the urinary tract infection), in this study, we further performed comparative genomic analysis for 10 selected Myroides strains. Our results showed that these Myroides genome contexts were very similar and phylogenetically related. Various prophages were identified in the four clinical isolate genomes, which possibly contributed to the genome evolution among the Myroides strains. CRISPR elements were only detected in the two clinical (PR63039 and CCUG10230) isolates and two environmental (CCUG12700 and H1bi) strains. With more stringent cutoff parameters in CARD analysis, the four clinical M. odoratimimus contained roughly equal antibiotic resistance genes, indicating their similar antibiotic resistance profiles. The three clinical (CCUG10230, CCUG12901, CIP101113) and three environmental (CCUG12700, L41, H1bi) M. odoratimimus strains were speculated to carry the indistinguishable virulent factors (VFs), which may involve in the similar pathogenesis mechanism. Moreover, some VFs might confer to the high capacity of dissemination, attacking tissue cells and induction of autoimmune complications. Our results facilitate the research of antibiotic resistance and the development of therapeutic regimens for the M. odoratimimus infections.

Oxidative Stress Induces HSP90 Upregulation on the Surface of Primary Human Endothelial Cells: Role of the Antioxidant 7,8-Dihydroxy-4-methylcoumarin in Preventing HSP90 Exposure to the Immune System

We have previously demonstrated that human heat shock protein 90 (HSP90), an intracellular self protein, is the target of cellular and humoral autoimmune responses in patients with carotid atherosclerosis. In this study, we evaluated in vitro whether oxidative stress, a feature of atherosclerotic plaque, alters HSP90 expression in endothelial cells, thus inducing surface localization of this molecule and whether the antioxidant compound 7,8-dihydroxy-4-methylcoumarin (7,8-DHMC) is able to prevent oxidative stress-induced alterations of HSP90 localization. By the use of flow cytometry, immunofluorescence, enzyme-linked immunosorbent assay, and semiquantitative reverse-transcription polymerase chain reaction, we demonstrated that exposure of human umbilical vein endothelial cells (HUVEC) to the prooxidant compound H₂O₂ upregulated HSP90 surface expression and reduced its secretion without altering HSP90 gene expression and intracytoplasmic protein levels. Pretreatment of HUVEC with 7,8-DHMC prevented H₂O₂-induced alterations of HSP90 cellular distribution and secretion. Our results suggest that the strong oxidative conditions of atherosclerotic plaques promote the upregulation of HSP90 surface expression on endothelial cells, thus rendering the protein a possible target of autoimmune reactions. The antioxidant 7,8-DHMC, by preventing oxidative-stress-triggered HSP90 surface upregulation, may be useful to counteract possible autoreactive reactions to HSP90.

Trimethylamine-N-oxide, as a risk factor for atherosclerosis, induces stress in J774A.1 murine macrophages

PURPOSE

Trimethylamine N-oxide (TMAO) is a biomarker for kidney problems. It has also been introduced as a risk factor for atherosclerosis. The classic risk factors for atherosclerosis trigger cellular and humeral immunoreaction in macrophages through induction of heat shock protein expressions and increased levels of GRP94 and HSP70 are associated with increased atherosclerosis risk. The present study evaluated the possible effect(s) of TMAO on the expression of GRP94 and HSP70 at protein levels.

METHODS

J774A.1 murine macrophages were treated with different micromolar concentrations of TMAO and 4-phenylbutyric acid (PBA), a chemical chaperone, for 8, 18, 24, and 48h intervals. Tunicamycin was also used as a control for induction of endoplasmic reticulum stress. Western blotting was used to evaluate the expression of GRP94 and HSP70 in macrophages at protein levels.

RESULT

Tunicamycin greatly increased protein levels of GRP94. Similarly, but to a lesser extent compared to tunicamycin, TMAO also increased GRP94. In 24h treated cells, only 300μM of TMAO, and in cells treated for 48h, all doses of TMAO produced a significant increase in relative HSP70 protein levels compared to the control. PBA failed to induce any changes in GRP94 or HSP70 protein levels.

CONCLUSION

GRP94 and HSP70 are stress-inducible heat shock protein, so the elevation in J774A.1 murine macrophages can clearly define cells under stress and elucidate the contribution of stress induced by TMAO that may have a part in the abnormal activation of macrophages involved in foam cell formation.

Pleiotropic Meta-Analyses of Longitudinal Studies Discover Novel Genetic Variants Associated with Age-Related Diseases

Age-related diseases may result from shared biological mechanisms in intrinsic processes of aging. Genetic effects on age-related diseases are often modulated by environmental factors due to their little contribution to fitness or are mediated through certain endophenotypes. Identification of genetic variants with pleiotropic effects on both common complex diseases and endophenotypes may reveal potential conflicting evolutionary pressures and deliver new insights into shared genetic contribution to healthspan and lifespan. Here, we performed pleiotropic meta-analyses of genetic variants using five NIH-funded datasets by integrating univariate summary statistics for age-related diseases and endophenotypes. We investigated three groups of traits: (1) endophenotypes such as blood glucose, blood pressure, lipids, hematocrit, and body mass index, (2) time-to-event outcomes such as the age-at-onset of diabetes mellitus (DM), cancer, cardiovascular diseases (CVDs) and neurodegenerative diseases (NDs), and (3) both combined. In addition to replicating previous findings, we identify seven novel genome-wide significant loci (< 5e-08), out of which five are low-frequency variants. Specifically, from Group 2, we find rs7632505 on 3q21.1 in SEMA5B, rs460976 on 21q22.3 (1 kb from TMPRSS2) and rs12420422 on 11q24.1 predominantly associated with a variety of CVDs, rs4905014 in ITPK1 associated with stroke and heart failure, rs7081476 on 10p12.1 in ANKRD26 associated with multiple diseases including DM, CVDs, and NDs. From Group 3, we find rs8082812 on 18p11.22 and rs1869717 on 4q31.3 associated with both endophenotypes and CVDs. Our follow-up analyses show that rs7632505, rs4905014, and rs8082812 have age-dependent effects on coronary heart disease or stroke. Functional annotation suggests that most of these SNPs are within regulatory regions or DNase clusters and in linkage disequilibrium with expression quantitative trait loci, implying their potential regulatory influence on the expression of nearby genes. Our mediation analyses suggest that the effects of some SNPs are mediated by specific endophenotypes. In conclusion, these findings indicate that loci with pleiotropic effects on age-related disorders tend to be enriched in genes involved in underlying mechanisms potentially related to nervous, cardiovascular and immune system functions, stress resistance, inflammation, ion channels and hematopoiesis, supporting the hypothesis of shared pathological role of infection, and inflammation in chronic age-related diseases.

Exogenous hydrogen sulfide exerts proliferation, anti-apoptosis, angiopoiesis and migration effects via activating HSP90 pathway in EC109 cells

Hydrogen sulfide (H2S) participates in diverse physiological and pathophysiologic processes of cancer both in vitro and in vivo. We have previously reported the proliferation/anti-apoptosis/angiogenesis/migration effects of exogenous H2S on liver cancer and glioma via amplifying the activation of NF-κB and p38 MAPK/ERK1/2-COX-2 pathway. However, the effects of H2S on EC109 esophageal cells remain unclear. The present study demonstrated the effects of exogenous H2S on cancer cell growth via activating HSP90 pathways in EC109 esophageal cells. EC109 esophageal cells were treated with 400 µmol/l NaHS (a donor of H2S) for 24 h. The expression levels of HSP90, bcl-2, caspase-3, bax and MMP-2 were detected by western blot assay. Cell viability was detected by Cell Counting Kit-8 (CCK-8). The migration rate was analyzed using a Transwell migration assay and ImageJ software. NaHS promoted cell proliferation, as evidenced by an increase in cell viability. In addition, NaHS treatment reduced apoptosis, as indicated by the increased bcl-2 expression and decreased cleaved caspase-3 and bax expression. Importantly, exposure of NaHS increased the expression of MMP-2, the migration rate and expression of VEGF. Notably, co-treatment of EC109 cells with NaHS and GA (an inhibitor of HSP90 pathway) largely suppressed the aforementioned NaHS-induced effects. The findings of the present study provided novel evidence that HSP90 pathway was involved in NaHS-induced cancer cell proliferation, anti-apoptosis, angiopoiesis and migration in EC109 esophageal cells.

Autophagic marker MAP1LC3B expression levels are associated with carotid atherosclerosis symptomatology

Objectives

The mechanism by which atheroma plaque becomes unstable is not completely understood to date but analysis of differentially expressed genes in stable versus unstable plaques may provide clues. This will be crucial toward disclosing the mechanistic basis of plaque instability, and may help to identify prognostic biomarkers for ischaemic events. The objective of our study was to identify differences in expression levels of 59 selected genes between symptomatic patients (unstable plaques) and asymptomatic patients (stable plaques).

Methods

80 carotid plaques obtained by carotid endarterectomy and classified as symptomatic (>70% stenosis) or asymptomatic (>80% stenosis) were used in this study. The expression levels of 59 genes were quantified by qPCR on RNA extracted from the carotid plaques obtained by endarterectomy and analyzed by means of various bioinformatic tools.

Results

Several genes associated with autophagy pathways displayed differential expression levels between asymptomatic and symptomatic (i.e. MAP1LC3B, RAB24, EVA1A). In particular, mRNA levels of MAP1LC3B, an autophagic marker, showed a 5−fold decrease in symptomatic samples, which was confirmed in protein blots. Immune system−related factors and endoplasmic reticulum-associated markers (i.e. ERP27, ITPR1, ERO1LB, TIMP1, IL12B) emerged as differently expressed genes between asymptomatic and symptomatic patients.

Conclusions

Carotid atherosclerotic plaques in which MAP1LC3B is underexpressed would not be able to benefit from MAP1LC3B−associated autophagy. This may lead to accumulation of dead cells at lesion site with subsequent plaque destabilization leading to cerebrovascular events. Identified biomarkers and network interactions may represent novel targets for development of treatments against plaque destabilization and thus for the prevention of cerebrovascular events.

Heat shock proteins and cardiovascular disease

Atherosclerosis is the leading global cause of mortality, morbidity, and disability. Heat shock proteins (HSPs) are a highly conserved family of proteins with diverse functions expressed by all cells exposed to environmental stress. Studies have reported that several HSPs may be potential risk markers of atherosclerosis and related cardiovascular diseases, or may be directly involved in the atherogenic process itself. HSPs are expressed by cells in atherosclerotic plaque and anti-HSP has been reported to be increased in patients with vascular disease. Autoimmune responses may be generated against antigens present within the atherosclerotic plaque, including HSP and may lead to a cycle of ongoing vascular injury. It has been suggested that by inducing a state of tolerance to these antigens, the atherogenic process may be limited and thus provide a potential therapeutic approach. It has been suggested that anti-HSPs are independent predictors of risk of vascular disease. In this review, we summarize the current understanding of HSP in cardiovascular disease and highlight their potential role as diagnostic agents and therapeutic targets.

Differential humoral responses against heat-shock proteins after autologous stem cell transplantation in multiple myeloma

Heat-shock proteins (HSP) are important molecules in the pathogenesis of multiple myeloma (MM). Their blockages by drugs or cellular immune response have been investigated, and a possible association with the presence of oligoclonal bands (OB) has been postulated in patients with MM after allogenic stem cell transplantation. The aim of the present study was to ascertain the serum antibody levels against three HSP (60, 70 and 90) by ELISA in patients with MM in complete remission after autologous stem cell transplantation (ASCT), with or without OB, and compare them with those patients with stable gammopathy of undetermined significance (MGUS) and healthy controls. Our results in samples after ASCT showed no differential levels of anti-HSP according to the presence or absence of the oligoclonal response. However, higher levels of anti-HSP90 were found in patients with stable MGUS in comparison with MM patients (p = 0.004). In the same line, a longer progression-free survival was observed in those patients who presented higher anti-HSP90 levels after ASCT (p = 0.042). These results suggest, for first time, the potential of anti-HSP90 humoral immune response for long-term control of malignant plasma cell disorders.

Inflammatory biomarkers for predicting cardiovascular disease

The pathology of cardiovascular disease (CVD) is complex; multiple biological pathways have been implicated, including, but not limited to, inflammation and oxidative stress. Biomarkers of inflammation and oxidative stress may serve to help identify patients at risk for CVD, to monitor the efficacy of treatments, and to develop new pharmacological tools. However, due to the complexities of CVD pathogenesis there is no single biomarker available to estimate absolute risk of future cardiovascular events. Furthermore, not all biomarkers are equal; the functions of many biomarkers overlap, some offer better prognostic information than others, and some are better suited to identify/predict the pathogenesis of particular cardiovascular events. The identification of the most appropriate set of biomarkers can provide a detailed picture of the specific nature of the cardiovascular event. The following review provides an overview of existing and emerging inflammatory biomarkers, pro-inflammatory cytokines, anti-inflammatory cytokines, chemokines, oxidative stress biomarkers, and antioxidant biomarkers. The functions of each biomarker are discussed, and prognostic data are provided where available.

T lymphocyte autoreactivity in inflammatory mechanisms regulating atherosclerosis

Atherosclerosis has been clearly demonstrated to be a chronic inflammatory disease of the arterial wall. Both cells of the innate and the acquired immune system, particularly monocytes and T lymphocytes, are implicated in the atherogenic process, producing different cytokines with pro- and anti-inflammatory effects. The majority of pathogenic T cells involved in atherosclerosis are of the Th1 profile, that has been correlated positively with coronary artery disease. Many studies conducted to evaluate the molecular factors responsible for the activation of T cells have demonstrated that the main antigenic targets in atherosclerosis are modified endogenous structures. These self-molecules activate autoimmune reactions mainly characterized by the production of Th1 cytokines, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper we will summarize the different T-cell subsets involved in atherosclerosis and the best characterized autoantigens involved in cardiovascular inflammation.

Hsp70-2 gene polymorphism: susceptibility implication in Tunisian patients with coronary artery disease

Abstract

Coronary artery disease (CAD) is a multifactorial disease where genetic and environmental factors interact in complex ways to cause the disease. Heat shock protein genes are involved in the progress of CAD. This implies that genetic variants of Hsp70–2 genes might contribute to the development of the CAD.

Aim of study

The aim of this study was to characterize statistical correlation of linkage between lipid profiles, polymorphism PstI site of Hsp70–2 gene and CAD.

Patients and methods

This study was carried out on Tunisian patients with CAD recruited from Hospital of Fattouma Bourguiba of Monastir-Tunisia. Polymerase chain reaction and restriction enzymes were used to determine the genotypic distributions in 252 unrelated patients and 151 healthy control subjects. Further, ApoA-I and ApoB as well as the serum total of cholesterol, HDL, triglyceride, and hs-CRP levels were measured.

Results

We showed a decreased level of ApoA-I, whereas the levels of each of ApoB and hs-CRP were increased in patients with CAD compared with control group. In addition our studies of a polymorphic PstI site of Hsp70-2 gene at position 1267 of the Hsp70–2 gene have revealed that the allelic frequency of P2 was significantly more frequent in CAD patients than controls group (p=0.007, OR=1.495). The genotypic distribution showed a high incidence of P2/P2 genotype in CAD patients (0.190) compared to healthy control (0.009) with reach significant difference (p=0.006). The P2 carriers showed a significantly increased of Total-Cholesterol (CT) and C-reactive protein (hs-CRP) levels in CAD patients (p=0.008 and p=0.018, respectively).

Conclusion

The high incidence of P2-Hsp70-2 genotype in CAD patients and the significantly association of P2/P2 genotype with elevated Total Cholesterol and hs-CRP levels, supported that P2–Hsp70–2 genotype has susceptibility implication in CAD and could increased the risk of CAD in Tunisian population.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1118340895703689

Genetic variations of HSPA1A, the heat shock protein levels, and risk of atherosclerosis

HSPA1A is a serum and intracellular heat shock protein with antiapoptotic and antithrombotic properties. The present study examines the hypothesis that a decrease in the synthesis of this protein in relation to certain polymorphisms of the regulatory region of the HSPA1A gene can define a vascular disease risk phenotype. A randomly selected population was studied and stratified into groups according to the degree of vascular risk. After applying the Task Force Chart to 452 people, the subjects were divided into three groups: group 0 (no vascular risk factor or risk < 5%), n = 239; group 1 (moderate (10-20%) risk, with no clinical cardiovascular disease), n = 161; and group 2 (overt atherosclerosis), n = 52. Serum and intragranulocytic HSPA1A was quantified, and direct Sanger sequencing was performed in all subjects. An analysis was made of the association of two single nucleotide polymorphisms (db rs1008438 -110A/C and db rs1043618 +190 G/C) with circulating and intragranulocytic HSPA1A and the risk of atherosclerosis. The atherosclerotic subjects showed significantly lower circulating HSPA1A levels than the other groups, regardless of the genotype. The patients with CC genotype for both polymorphisms showed significantly lower intragranulocytic HSPA1A levels than the other genotypes. Serum HSPA1A concentrations could be proposed as a biomarker of cardiovascular disease. CC homozygosis for polymorphisms db rs1008438 and db rs1043618 is associated with a decrease in the intragranulocytic production of HSPA1A. Given the antiatherogenic functions of intracellular HSPA1A, the -110A and +190 G alleles could constitute potential genetic biomarkers of a less severe clinical phenotype for the risk of developing atherosclerosis.

Oxidative stress in cardiovascular inflammation: its involvement in autoimmune responses

Recently, it has become clear that atherosclerosis is a chronic inflammatory disease in which inflammation and immune responses play a key role. Accelerated atherosclerosis has been reported in patients with autoimmune diseases, suggesting an involvement of autoimmune mechanisms in atherogenesis. Different self-antigens or modified self-molecules have been identified as target of humoral and cellular immune responses in patients with atherosclerotic disease. Oxidative stress, increasingly reported in these patients, is the major event causing structural modification of proteins with consequent appearance of neoepitopes. Self-molecules modified by oxidative events can become targets of autoimmune reactions, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper, we will summarize the best characterized autoantigens in atherosclerosis and their possible role in cardiovascular inflammation.

Serum antibody titers against heat shock protein 27 are associated with the severity of coronary artery disease

Antibody titers to several heat shock proteins (anti-Hsps) have been reported to be associated with the severity and progression of cardiovascular disease. However, there are little data regarding anti-Hsp27 titers in patients with coronary artery disease (CAD). A total of 400 patients with suspected CAD were recruited. Based on the results of coronary angiography, these patients were classified into CAD(+) (n = 300) and CAD(-) (n = 100) groups defined as patients with ≥50% and <50% stenosis of any major coronary artery, respectively. Eighty-three healthy subjects were also recruited as the control group. Serum anti-Hsp27 IgG titers were measured using an in-house enzyme-linked immunosorbent assay. CAD(+) patients had significantly higher anti-Hsp27 titers compared with both CAD(-) and control groups. Anti-Hsp27 titers were also higher in the CAD(-) group compared with the control group. With regard to the number of affected vessels in the CAD(+) group, patients with three-vessel disease had higher anti-Hsp27 titers compared with both two-vessel disease (2VD) and one-vessel disease (1VD) subgroups. However, there was no significant difference between 1VD and 2VD subgroups. In multiple linear regression analysis, the number of narrowed vessels and smoking were significant independent determinants of serum anti-Hsp27 titers. The present findings indicate that serum anti-Hsp27 titers may be associated with the presence and severity of coronary artery disease.

Extracellular heat shock protein 70 (HSPA1A) and classical vascular risk factors in a general population

Atherosclerosis is a chronic inflammatory and autoimmune disease. Candidate molecules/autoantigens include heat shock proteins (HSPs); Hsp70 (HSPA1A) is one of the best studied HSPs. Various studies have shown a correlation between extracellular Hsp70 (eHsp70) and anti-Hsp70/anti-Hsp60 antibody concentration and development of atherosclerosis. A random sample of 456 people aged 40-60 (218 males, 234 females) was studied to investigate the prevalence of traditional vascular risk factors and eHsp70 and anti-Hsp70/anti-Hsp60 antibodies levels, according to the risk of vascular disease. Task Force Chart was applied for classification. Subjects were divided into three groups: G0 (with no vascular risk factor or a risk lower than 5%), n = 239; G1 (moderated 10-20% risk, who do not have established disease) n = 161; and G2 (established atherosclerosis disease) n = 52. eHsp70 and anti-Hsp70 were significantly lower in the atherosclerosis group (group 2) with respect to the other groups. Disease-free people showed the highest anti-Hsp60 concentration compared with the other two groups. A correlation has not been demonstrated between the concentrations of circulating Hsp70 (HSPA1A), anti-Hsp70, and anti-Hsp60 and classical vascular risk factors and C-reactive protein. Low levels of eHsp70 and anti-Hsp70 antibodies should be considered as candidate FRV. Simultaneous decrease of eHsp70 and anti-Hsp70 antibodies would be explained by circulating immune complex formation, and both could be proposed as biomarkers for the progression of atherosclerotic disease. Levels of circulating anti-Hsp60 antibodies may constitute a marker of inflammation in atherosclerosis.

Heat shock protein 70B' (HSP70B') expression and release in response to human oxidized low density lipoprotein immune complexes in macrophages

Heat shock proteins (HSPs) have been implicated in the activation and survival of macrophages. This study examined the role of HSP70B', a poorly characterized member of the HSP70 family, in response to oxidatively modified LDL (oxLDL) and immune complexes prepared with human oxLDL and purified human antibodies to oxLDL (oxLDL-IC) in monocytic and macrophage cell lines. Immunoblot analysis of cell lysates and conditioned medium from U937 cells treated with oxLDL alone revealed an increase in intracellular HSP70B' protein levels accompanied by a concomitant increase in HSP70B' extracellular levels. Fluorescence immunohistochemistry and confocal microscopy, however, demonstrated that oxLDL-IC stimulated the release of HSP70B', which co-localized with cell-associated oxLDL-IC. In HSP70B'-green fluorescent protein-transfected mouse RAW 264.7 cells, oxLDL-IC-induced HSP70B' co-localized with membrane-associated oxLDL-IC as well as the lipid moiety of internalized oxLDL-IC. Furthermore, the data demonstrated that HSP70B' is involved in cell survival, and this effect could be mediated by sphingosine kinase 1 (SK1) activation. An examination of regularly implicated cytokines revealed a significant relationship between HSP70B' and the release of the anti-inflammatory cytokine interleukin-10 (IL-10). Small interfering RNA knockdown of HSP70B' resulted in a corresponding decrease in SK1 mRNA levels and SK1 phosphorylation as well as increased release of IL-10. In conclusion, these findings suggest that oxLDL-IC induce the synthesis and release of HSP70B', and once stimulated, HSP70B' binds to the cell-associated and internalized lipid moiety of oxLDL-IC. The data also implicate HSP70B' in key cellular functions, such as regulation of SK1 activity and release of IL-10, which influence macrophage activation and survival.

Heat shock protein 70 enhances vascular bone morphogenetic protein-4 signaling by binding matrix Gla protein

RATIONALE

Matrix Gla protein (MGP) is a calcification inhibitor, which binds and inhibits bone morphogenetic protein (BMP)-2 and -4.

OBJECTIVE

The objective was to determine whether MGP also binds other proteins, which could interfere with its function.

METHODS AND RESULTS

We transfected bovine aortic endothelial cells with N-terminally FLAG-tagged MGP and used immunoprecipitation and liquid chromatographic-tandem mass spectrometric analysis to identify MGP-binding proteins. Heat shock protein (HSP)70, a stress-induced protein expressed in atherosclerotic lesions and soluble in serum, was identified as a novel MGP-binding protein. The interaction between MGP and HSP70 was confirmed by coimmunoprecipitation and chemical crosslinking, and blocked the interaction between MGP and BMP-4. In endothelial cells, HSP70 enhanced BMP-4-induced proliferation and tube formation, and in calcifying vascular cells, HSP70 enhanced BMP-induced calcium deposition. In addition, HSP70 mediated the procalcific effect of interleukin-6 on calcifying vascular cells. In apolipoprotein E-null mice, a model for atherosclerosis, levels of BMP-4, HSP70, MGP, and interleukin-6 were elevated in the aortic wall. Levels of BMP-4, HSP70, and interleukin-6 were also elevated in serum, and anti-HSP70 antibodies diminished its procalcific effect on calcifying vascular cells.

CONCLUSION

HSP70 binds MGP and enhances BMP activity, thereby functioning as a potential link between cellular stress, inflammation, and BMP signaling.

Hsp70 expression in monocytes from patients with peripheral arterial disease and healthy controls: monocyte Hsp70 in PAD

BACKGROUND

Heat shock proteins (HSP) are induced during cellular stress. Their role is to chaperone cellular proteins giving protection from denaturation and ultimately preventing cell death. Monocytes are key cells involved in atherosclerosis and are highly responsive to HSP induction. Therefore, we wished to examine monocyte Hsp70 expression and induction in patients with peripheral arterial disease (PAD) and in healthy controls.

METHODS

We measured cellular Hsp70 levels in freshly isolated monocytes and released Hsp70 levels in plasma and monocyte culture supernatants, obtained from patients with PAD and from healthy controls. We assessed the effect of statin therapy on Hsp70 levels and examined monocyte cell survival in culture with and without immunological stress.

RESULTS

Monocyte cellular Hsp70 was lower in patients with PAD compared to healthy controls (11.3 +/- 7.4 ng/10(6) cells vs 20.7 +/- 16.0 ng/10(6) cells; p < 0.001). Individuals on statin therapy from both PAD and control groups had lower monocyte Hsp70 compared to those not treated with statins. Concentrations of Hsp70 released into culture supernatants were not dependent on PAD or statin therapy. Cell survival was inversely associated with Hsp70 concentrations in culture supernatants but had no association with cellular concentrations of Hsp70.

CONCLUSIONS

Cellular Hsp70 and released Hsp70 may play different roles in monocyte health. Whilst induced Hsp70 destined for release appears to be unaffected in PAD, mechanisms responsible for cellular retention of Hsp70 may provide an area for future therapeutic targets in vascular disease.

Controlled delivery of heat shock protein using an injectable microsphere/hydrogel combination system for the treatment of myocardial infarction

Myocardial infarction causes a high rate of morbidity and mortality worldwide, and heat shock proteins as molecular chaperones have been attractive targets for protecting cardiomyoblasts under environmental stimuli. In this study, in order to enhance the penetration of heat shock protein 27 (HSP27) across cell membranes, we fused HSP27 with transcriptional activator (TAT) derived from human immunodeficiency virus (HIV) as a protein transduction domain (PTD). We loaded the fusion protein (TAT-HSP27) into microsphere/hydrogel combination delivery systems to control the release behavior for prolonged time periods. We found that the release behavior of TAT-HSP27 was able to be controlled by varying the ratio of PLGA microspheres and alginate hydrogels. Indeed, the released fusion protein maintained its bioactivity and could recover the proliferation of cardiomyoblasts cultured under hypoxic conditions. This approach to controlling the release behavior of TAT-HSP27 using microsphere/hydrogel combination delivery systems may be useful for treating myocardial infarction in a minimally invasive manner.

Multi-faceted role of HSP40 in cancer

HSP40 (DNAJ) is an understudied family of co-chaperones. The human genome codes for over 41 members of HSP40 family that reside at distinct intracellular locations. Despite their large numbers, little is known about their physiologic roles. Recent research has revealed involvement of some of the DNAJ family members in various types of cancers. In this article we summarize the information about the involvement of human DNAJ family members in various aspects of cancer biology. Furthermore we discuss the potential role of the J domain of DNAJ proteins in cancer biology.

YC-1 induces heat shock protein 70 expression and prevents oxidized LDL-mediated apoptosis in vascular smooth muscle cells

Heat shock protein 70 (hsp70) functioning as molecular chaperon in physiological conditions is induced under stress environment, which affords a defensive mechanism for cells to escape cellular damage. Hence, it is a critical issue to develop a nontoxic hsp70-inducing compound against cellular death. The present study was conducted to evaluate whether 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl-indazol (YC-1) can effectively induce hsp70 expression and protect vascular smooth muscle cells (VSMCs) against oxidized low-density lipoprotein-induced cytotoxicity. We showed that YC-1 enhanced hsp70 expression in VSMCs through a concentration- and time-dependent manner with maximum expression at 18 and 24 h without involving the cyclic guanosine monophosphate and reactive oxygen species signal in the pathway. Furthermore, we did not observe significant cytotoxicity after YC-1 treatment through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactic dehydrogenase, and fluorescence activating cell sorting scan assays. We demonstrated that the nuclear level of heat shock transcription factor 1 increased at 2 h after YC-1 treatment, and hsp70 expression was directed by the up-regulation of hsp70 mRNA, which peaked at 6 h and was followed by a decline. Hence, translocation of heat shock transcription factor 1 and increased level of hsp70 mRNA would account for Hsp70 expression. Finally, we found that YC-1 protects VSMCs from oxidized low-density lipoprotein-inducing apoptosis. According to our observations, YC-1 would be an effectively pharmacological hsp70 inducer that can be used as a cytoprotective agent in vascular diseases.

Reduction of heat shock protein antibody levels by statin therapy

Atherosclerosis is a disease whose pathogenesis involves inflammatory and immunological mechanisms, including an autoimmune reaction against heat shock proteins (Hsps). The purpose of this study was to analyze whether the antiatherogenic effect of statin therapy was not limited to its lipid lowering effect, but also included anti-inflammatory and immunomodulatory effects, paying special attention to the measurement of circulating concentrations of anti-Hsp70 and anti-Hsp60 antibodies previously related to vascular disease. Two-hundred and seventy-five subjects aged 40-60 years, randomly selected in an epidemiological study on the incidence of vascular risk factors, were studied. Laboratory tests included a complete lipid profile after a 12-h fast and measurements of glucose, C-reactive-protein, anti-Hsp70 and anti-Hsp60 antibodies. Subjects with hypercholesterolemia had significantly higher concentrations of anti-Hsp70 antibodies as compared to subjects with normal cholesterol concentrations. Statin therapy was associated with 11.63 and 15.3% reductions in total and LDL-cholesterol (P = 0.005 and 0.017, respectively) as compared to untreated subjects, and with lower concentrations of circulating anti-Hsp70 (P = 0.016) antibodies. No differences were found in C-reactive-protein values. Since statin therapy not only reduces lipid profile, but also anti-Hsp70 and anti-Hsp60 antibody concentrations, without changing C-reactive-protein values, it is suggested that such an effect could not be accounted for by the anti-inflammatory properties of statins, but by their direct immunomodulatory properties through their effects on lymphocyte function.

The autoimmune origin of atherosclerosis

Atherosclerosis is a chronic inflammatory disease. Many studies and observations suggest that it could be caused by an immune reaction against autoantigens at the endothelial level, the most relevant of which are oxidized LDL and heat shock proteins (HSP) 60/65. Endothelial dysfunction plays a fundamental role. The first antigen is related to the increased leakage and oxidation of LDL; the second to cellular reaction to stress. Experimental and clinical observations confirm the pathogenetic role of these antigens. Both innate and adaptive immunity and impaired regulatory mechanisms of the autoimmune reaction are involved. Different triggering factors are examined: infectious agents, smoking, air pollution, diabetes and hypercholesterolemia. Analogies and differences between systemic atherosclerosis and transplant-related coronary atherosclerosis help to understand their respective nature. Immune mechanisms might be responsible for the passage from stable plaque to unstable and rupture-prone plaque. Finally, prospects of treatment and prevention are linked to the induction of tolerance to responsible antigens, activation of immune regulatory response and the use of immunomodulatory drugs.

Small heat shock proteins in smooth muscle

The small heat shock proteins (HSPs) HSP20, HSP27 and alphaB-crystallin are chaperone proteins that are abundantly expressed in smooth muscles are important modulators of muscle contraction, cell migration and cell survival. This review focuses on factors regulating expression of small HSPs in smooth muscle, signaling pathways that regulate macromolecular structure and the biochemical and cellular functions of small HSPs. Cellular processes regulated by small HSPs include chaperoning denatured proteins, maintaining cellular redox state and modifying filamentous actin polymerization. These processes influence smooth muscle proliferation, cell migration, cell survival, muscle contraction and synthesis of signaling proteins. Understanding functions of small heat shock proteins is relevant to mechanisms of disease in which dysfunctional smooth muscle causes symptoms, or is a target of drug therapy. One example is that secreted HSP27 may be a useful marker of inflammation during atherogenesis. Another is that phosphorylated HSP20 which relaxes smooth muscle may prove to be highly relevant to treatment of hypertension, vasospasm, asthma, premature labor and overactive bladder. Because small HSPs also modulate smooth muscle proliferation and cell migration they may prove to be targets for developing effective, novel treatments of clinical problems arising from remodeling of smooth muscle in vascular, respiratory and urogenital systems.

Plasma concentration of heat shock protein 27 and risk of cardiovascular disease: a prospective, nested case-control study

BACKGROUND

Heat shock protein 27 (HSP27) has been hypothesized to be a potential biomarker of atherothrombosis. However, no prospective studies have yet been performed to investigate the association between HSP27 plasma concentration and incident cardiovascular events among initially healthy individuals.

METHODS

We evaluated plasma concentrations of HSP27 at baseline among 255 initially healthy participants in the Women's Health Study who subsequently developed myocardial infarction, ischemic stroke, or cardiovascular death during a follow-up period of up to 5.9 years and among an equal number of women matched for age and smoking but who remained free of cardiovascular disease over the same time period.

RESULTS

Overall, HSP27 plasma concentrations were inversely associated with age (Spearman correlation coefficient r = -0.258, P <0.001), but not with other established cardiovascular risk factors. Conditional logistic regression analysis showed no significant association of baseline HSP27 plasma concentration with future cardiovascular disease; the odds ratio for upper vs lower tertile of HSP27 concentration at baseline was 0.99 (95% CI 0.62-1.57, P for trend = 0.99).

CONCLUSION

In this prospective study of initially healthy women, baseline HSP27 plasma concentration was not associated with incident cardiovascular events.

Association of increased heat shock protein 70 levels in the lymphocyte with high risk of adverse pregnancy outcomes in early pregnancy: a nested case-control study

Studies suggest that heat shock proteins (Hsps), Hsp70 in particular, may play a role in embryogenesis and reproduction. As the first trimester is the critical period of human fetal development, we tested whether there is an association between Hsp70 expression in lymphocytes and adverse pregnancy outcomes (APOs) during that period. We measured lymphocyte Hsp70 levels by immunoblot in 55 pregnant women with APOs and 110 well-matched controls selected from 778 pregnant women in a nested case-control study. Multivariate logistic regression models were used to investigate the association between lymphocyte Hsp70 levels and risk of developing APOs. Our data showed that Hsp70 levels in women with APOs, especially those younger than 29 years old, were significantly higher than controls (193 vs 135 units, P < 0.001) and that the elevated Hsp70 levels were associated with a significantly increased risk of APOs (adjusted OR = 1.014; 95% CI = 1.008-1.020, P < 0.001). Our results also showed that the sensitivity, specificity, and positive and negative predictive values were 78%, 60%, 50%, and 85%, respectively, among these pregnant women. Adjusted ORs and 95% CI for the association between a Hsp70 value > 153 IOD and APOs were statistically significant (OR = 8.78, 95% CI = 2.79-27.64, P < 0.001). These results suggest that Hsp70 may play a role in the etiology of APOs. However, the underlying mechanisms for the elevation of Hsp70 in women with APOs and whether Hsp70 can be applied as a clinical indicator of APOs warrant further investigations.

Heat shock proteins and autoimmunity in patients with carotid atherosclerosis

Studies aimed at elucidating the pathogenetic mechanisms underlying the initiation and progression of human atherosclerosis have emphasized the central role of inflammatory and immune cells. Atherosclerotic plaques are infiltrated by activated macrophages, T and B lymphocytes, plasma cells, and mast cells, releasing inflammatory molecules, which amplify the severity of the disease. Endothelial cells subjected to various stress conditions express increased amounts of heat shock proteins (HSPs), some of the most successfully conserved proteins throughout evolution. Many experimental observations reviewed in this article draw attention to several HSPs targeted by a specific cellular and humoral immune response in patients with atherosclerotic disease. The review also reports preliminary data obtained by our group on the possible role of HSP90 as a candidate autoantigen in carotid atherosclerosis. Our study deals with the presence of specific antibodies and T cells directed against HSP90 in patients with carotid atherosclerotic plaques. In 60% of these subjects' sera but in none of the sera from healthy controls immunoblotting (IB) detected the presence of specific antibodies. Moreover, 20% of peripheral blood mononuclear cells (PBMC) samples from patients but none from healthy subjects proliferated in response to human purified HSP90. In vitro experiments showed an upregulation of HSP90 expression in endothelial cells exposed to oxidative stress by treatment with H(2)O(2) and greater release of soluble HSP90 in culture supernatants from H(2)O(2)-treated cells than from untreated cells.

Expression of heat shock proteins and stress fiber formation within the arterial vascular tree of adult rats under normal physiological conditions

In this study, we investigated heat shock protein (HSP) expression and stress fiber (SF) formation in endothelial cells (ECs) within the arterial vascular tree of adult rats under normal physiological conditions. Using quantitative immunofluorescence microscopy, we found no significant differences in expression of HSPs 25, 60, 70, and 90 among ECs in the straight portions of rat arteries. In these regions, ECs appeared spindle-shaped and contained short bundles of central SFs. In contrast, ECs in the curved portions or the branch sites of the arteries, exhibited striking differences in HSP expression. ECs with higher HSP expression were localized at the lesser curvature in the curved portions or the distal site of the branch ostia. Moreover, the ECs became polygonal and contained irregular central SFs at the lesser curvature. At the branch sites, downstream ECs became spear-shaped and contained long, thick bundles of central SFs. Curved portions or branch sites are the regions of disturbed flow at which early atherosclerotic lesions are often found. Our results demonstrate these positional differences in HSP expression associated with changes in SF formation within the arterial vascular tree under non-pathological conditions. Our study provides basic information for understanding stress responses via HSP expression and SF formation in vascular ECs and the pathogenesis of atherosclerotic disease.

Role of heat shock protein 70 in induction of stress fiber formation in rat arterial endothelial cells in response to stretch stress

We investigated the mechanism by which endothelial cells (ECs) resist various forms of physical stress using an experimental system consisting of rat arterial EC sheets. Formation of actin stress fibers (SFs) and expression of endothelial heat-shock stress proteins (HSPs) in response to mechanical stretch stress were assessed by immunofluorescence microscopy. Stretch stimulation increased expression of HSPs 25 and 70, but not that of HSP 90. Treatment with SB203580, a p38 MAP kinase inhibitor that acts upstream of the HSP 25 activation cascade, or with geldanamycin, an inhibitor of HSP 90, had no effect on the SF formation response to mechanical stretch stress. In contrast, treatment with quercetin, an HSP 70 inhibitor, inhibited both upregulation of endothelial HSP 70 and formation of SFs in response to tensile stress. In addition, treatment of stretched ECs with cytochalasin D, which disrupts SF formation, did not adversely affect stretch-induced upregulation of endothelial HSP 70. Our data suggest that endothelial HSP 70 plays an important role in inducing SF formation in response to tensile stress.

Modulation of endothelial cell damages by anti-Hsp60 autoantibodies in systemic autoimmune diseases

Heat-shock protein (Hsp) family is made up of heterogeneous proteins of which Hsp60 members are the most studied. It is now generally admitted that Hsp60 is not only a mitochondrial component but can be localized on the membrane cell surface. Considered as a signal danger following infections, Hsp60 can induce the production of anti-Hsp60 antibodies as defense mechanisms against pathogens. However, endogenous Hsp60 is also a target of autoantibodies in autoimmune disorders, atherosclerosis and vascular diseases, in which anti-endothelial cell antibodies (AECA) are generated. Hsp60 is one of the endothelial cell autoantigens able to trigger cytotoxic and apoptotic responses when recognized by the related autoantibodies. Depending on the Hsp60 epitope specificity, it appears that AECA with Hsp60 reactivity may differ in their functional effects. These observations suggest that new therapeutic approach to avoid endothelial cell damages due to anti-Hsp60 autoantibodies would be successful provided that specific Hsp60 epitopes would have been precisely characterized.

Inflammatory events in a vascular remodeling model induced by surgical injury to the rat carotid artery

1.--The aim of our study was to gain insight into the molecular and cellular mechanisms of the inflammatory response to arterial injury in a rat experimental model. 2.--Rats (five for each experimental time) were subjected to brief clamping and longitudinal incision of a carotid artery and monitored for 30 days. Subsequently, Nuclear Factor-kappaB (NF-kappaB) expression was measured by electrophoretic mobility shift assay. Heat shock protein (HSP) 27, HSP47 and HSP70 were evaluated by Western blot. Morphological changes of the vessel wall were investigated by light and electron microscopy. 3.--In injured rat carotid artery NF-kappaB activity started immediately upon injury, and peaked between 2 and 3 weeks later. Western blot showed a significant increase of HSP47 and HSP70 7 days after injury. At 2 weeks postinjury, HSP27 expression peaked. Light microscopy showed a neointima formation, discontinuity of the media layer and a rich infiltrate. Among infiltrating cells electron microscopy identified dendritic-like cells in contact with lymphocytes. 4.--Our model of surgical injury induces a significant inflammatory process characterized by enhanced NF-kappaB activity and HSPs hyperexpression. Dendritic-like cells were for the first time identified as a novel component of tissue repair consequent to acute arterial injury.

Genotype x adiposity interaction linkage analyses reveal a locus on chromosome 1 for lipoprotein-associated phospholipase A2, a marker of inflammation and oxidative stress

Because obesity leads to a state of chronic, low-grade inflammation and oxidative stress, we hypothesized that the contribution of genes to variation in a biomarker of these two processes may be influenced by the degree of adiposity. We tested this hypothesis using samples from the San Antonio Family Heart Study that were assayed for activity of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), a marker of inflammation and oxidative stress. Using an approach to model discrete genotypexenvironment (GxE) interaction, we assigned individuals to one of two discrete diagnostic states (or "adiposity environments"): nonobese or obese, according to criteria suggested by the World Health Organization. We found a genomewide maximum LOD of 3.39 at 153 cM on chromosome 1 for Lp-PLA(2). Significant GxE interaction for Lp-PLA(2) at the genomewide maximum (P=1.16 x 10(-4)) was also found. Microarray gene-expression data were analyzed within the 1-LOD interval of the linkage signal on chromosome 1. We found two transcripts--namely, for Fc gamma receptor IIA and heat-shock protein (70 kDa)--that were significantly associated with Lp-PLA(2) (P<.001 for both) and showed evidence of cis-regulation with nominal LOD scores of 2.75 and 13.82, respectively. It would seem that there is a significant genetic response to the adiposity environment in this marker of inflammation and oxidative stress. Additionally, we conclude that GxE interaction analyses can improve our ability to identify and localize quantitative-trait loci.

Association between indices of body mass and antibody titres to heat-shock protein-60, -65 and -70 in healthy Caucasians

We have previously shown that antibody titres to several heat-shock proteins (Hsps) are elevated in dyslipidaemic patients and subjects with established vascular disease. Obesity is known to be associated with raised serum inflammatory markers suggesting a state of heightened immune activation. Hence, we have investigated the association between indices of obesity and several Hsp antibody titres in healthy subjects. Subjects (n=170) were recruited from among employees at the University of Surrey and the Royal Surrey County Hospital, Guildford, UK. Of these subjects, 35 were obese with a body mass index (BMI)>/=30 kg/m(2) (19 male and 16 female subjects), 58 were overweight with 30>BMI>/=25 kg/m(2) (36 male and 22 female subjects) and 77 were of a normal weight with BMI<25 kg/m(2) (31 male and 46 female subjects). Overall, obese subjects had significantly higher plasma anti-Hsp-60 (P<0.001), anti-Hsp-65 (P<0.05) and anti-Hsp-70 (P<0.05) compared with overweight and normal weight subjects.

Interaction of pro-apoptotic protein HGTD-P with heat shock protein 90 is required for induction of mitochondrial apoptotic cascades

HGTD-P is a hypoxia-responsive pro-apoptotic protein that transmits hypoxic signals directly to mitochondria. When overexpressed, HGTD-P induces cell death via typical mitochondrial apoptotic cascades. However, much is unknown about post-transcriptional modification and signaling networks of HGTD-P in association with cell death-regulating proteins. We performed yeast two-hybrid screening to identify the molecules involved in HGTD-P-mediated cell death pathways. In this study, we show that heat shock protein 90 physically interacts with HGTD-P and that suppression of Hsp90 activity by low concentrations of geldanamycin reduced HGTD-P-induced mitochondrial catastrophe through inhibition of mitochondrial translocation of HGTD-P.

Accelerated atherosclerosis, immune response and autoimmune rheumatic diseases

Atherosclerosis (AT) is a chronic autoimmune inflammatory disease, characterized by lipoproteins metabolism alteration leading to formation of pro-inflammatory and pro-oxidative lipids and immune response. Identification of macrophages, T cells, pro-inflammatory cytokines, adhesion cell molecules in atherosclerotic lesions support the hypothesis that innate and adaptive immune response participate in the atherogenesis mechanism. Multiple factors such as inflammatory, infectious and immune system, among others participate in this process. The principal antigens identified in atherogenesis are: oxidized LDL (oxLDL), HSPs and beta2GPI. During LDL oxidation, multiple neoantigens are formed (anti-EO). These antibodies seem to be protective. Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) have accelerated AT. The association of both diseases with AT suggests a common pathogenic mechanism. SLE and atherosclerosis are immune-complex mediated diseases. Participation of complement activation, and CD40, CD40 ligand interactions have been demonstrated in AT and SLE. AT may be the initial presentation or the consequence of primary antiphospholipid syndrome. The similarities between AT, SLE, and APS and the identification of protective antibodies offer opportunities for new immunomodulation treatment strategies.

Antibodies against heat shock proteins in environmental stresses and diseases: friend or foe?

Heat shock proteins (Hsps) can be found in two forms, intracellular and extracellular. The intracellular Hsps are induced as a result of stress and have been found to be cytoprotective in many instances due to their chaperone functions in protein folding and in protein degradation. The origin and role of extracellular Hsps is less clear. Although they were suspected originally to be released from damaged cells (necrosis), their presence in most normal individuals rather suggests that they have regulatory functions in circulation. As immunodominant molecules, Hsps can stimulate the immune system, leading to the production of autoantibodies recognizing epitopes shared by microbial and human Hsps. Thus, extracellular Hsps can influence the inflammatory response as evidenced by the production of inflammatory cytokines. Antibodies to Hsps have been found under normal conditions but seem to be increased in certain stresses and diseases. Such antibodies could regulate the inflammatory response positively or negatively. Here, we review the literature on the findings of antibodies to Hsps in situations of environmental or occupational stress and in a number of diseases and discuss their possible significance for the diagnosis, prognosis, or pathogenesis of these diseases.

Major role of HSP70 as a paracrine inducer of cytokine production in human oxidized LDL treated macrophages

Lipid accumulation and inflammation are key hallmarks of the atherosclerotic plaque and macrophage uptake of oxidized low-density lipoprotein (oxLDL) is believed to drive these processes. Initial experiments show that supernatants from oxLDL treated macrophages could induce IL-1beta production in naïve macrophages. To search for potential paracrine mediators that could mediate this effect a DNA microarray scan of oxLDL treated human macrophages was performed. This analysis revealed that oxLDL induced activation of heat shock protein (HSP) expression. HSPs have been implicated in the development of atherosclerosis, but the exact mechanisms for this is unclear. Extracellular heat shock protein 70 (HSP70) has been shown to elicit a pro-inflammatory cytokine response in monocytes and could therefore be a potential paracrine pro-inflammatory mediator. After 24 h of oxLDL treatment there was a significant increase of HSP70 concentrations in supernatants from oxLDL treated macrophages (oxLDLsup) compared to untreated controls (P<0.05). OxLDLsup could induce both interleukin (IL)-1beta and IL-12 secretion in naïve macrophages. We also demonstrate that the effect of oxLDLsup on cytokine production and release could be blocked by inhibition of HSP70 transcription or secretion or by the use of HSP70 neutralizing antibodies. This suggests that extracellular HSP70 can mediate pro-inflammatory changes in macrophages in response to oxLDL.