Anti-Hsp90 therapy in autoimmune and inflammatory diseases: a review of preclinical studies

Dehydroepiandrosterone ameliorates primary dysmenorrhea by suppressing the SP1/Hsp90ab1/COX-2 signaling pathway

Androgens play a protective role in alleviating chronic pain in women, including pelvic pain; however, their specific role and underlying mechanism in the treatment of primary dysmenorrhea (PD) remain unclear. In this study, clinical data revealed that women with PD exhibited reduced serum testosterone levels, which were inversely correlated with the severity of dysmenorrhea compared to healthy controls. Using a mouse model of PD, we observed significant upregulation of Hsp90ab1 and the PD markers COX-2 in the uterus. Treatment with dehydroepiandrosterone (DHEA), an androgen precursor, suppressed the uterine expression of Hsp90ab1 and COX-2, alleviating pain symptoms. Notably, pharmacological inhibition of Hsp90ab1 with geldanamycin reduced COX-2 expression by inactivating the p-p38 and p-JNK signaling pathways, and effectively mitigated PD. Further analysis identified specificity protein 1 (SP1) as a key driver of Hsp90ab1 transcription through its binding to the promoter region. Inhibition of SP1 using plicamycin reduced Hsp90ab1 expression, alleviated pain, and decreased uterine edema in the mouse model. Conversely, lentiviral overexpression of Hsp90ab1 reversed the therapeutic effects of DHEA, including nociception relief, reduction of uterine edema, and suppression of COX-2 expression. These findings suggest that androgen deficiency triggers SP1-mediated upregulation of Hsp90ab1 and COX-2, forming a critical regulatory loop that exacerbates menstrual cramps. Targeting this pathway represents a promising therapeutic strategy for managing PD.

The Role of HSP90 Molecular Chaperones in Depression: Potential Mechanisms

Major depressive disorder (MDD) is characterized by high rates of disability and death and has become a public health problem that threatens human life and health worldwide. HPA axis disorder and neuroinflammation are two common biological abnormalities in MDD patients. Hsp90 is an important molecular chaperone that is widely distributed in the organism. Hsp90 binds to the co-chaperone and goes through a molecular chaperone cycle to complete its regulation of the client protein. Numerous studies have demonstrated that Hsp90 regulates how the HPA axis reacts to stress and how GR, the HPA axis' responsive substrate, matures. In addition, Hsp90 exhibits pro-inflammatory effects that are closely related to neuroinflammation in MDD. Currently, Hsp90 inhibitors have made some progress in the treatment of a variety of human diseases, but they still need to be improved. Further insight into the role of Hsp90 in MDD provides new ideas for the development of new antidepressant drugs targeting Hsp90.

Polydatin-Mediated Inhibition of HSP90α Disrupts NLRP3 Complexes and Alleviates Acute Pancreatitis

The NLRP3 inflammasome plays a critical role in various inflammatory conditions. However, despite extensive research in targeted drug development for NLRP3, including MCC950, clinical success remains elusive. Here, we discovered that the activated NLRP3 inflammasome complex (disc-NLRP3) and the activating mutation L351P exhibited resistance to MCC950. Through investigations using the small-molecule compound polydatin, HSP90α was found to stabilize both the resting (cage-NLRP3) and activated state (disc-NLRP3) of NLRP3 complexes, sustaining its activation. Our mechanistic studies revealed that polydatin specifically targets HSP90α, binding to it directly and subsequently interfering with the HSP90α-NLRP3 interaction. This disruption leads to the dissipation of cage-NLRP3, disc-NLRP3 complexes and NLRP3 L351P. Importantly, genetic and pharmacological inactivation of HSP90α effectively reduced NLRP3 inflammasome activation and alleviated cerulein-induced acute pancreatitis. These therapeutic effects highlight the clinical potential of HSP90α inhibition. Our findings demonstrate that HSP90α is crucial for the stability of both the resting and activated states of the NLRP3 inflammasome during its sustained activation, and targeting HSP90α represents a promising therapeutic strategy for diseases driven by the NLRP3 inflammasome.

Hepatic immune response of Coilia nasus infected with Anisakidae during ovarian development

Anisakidae parasitism is a prevalent disease in wild populations of Coilia nasus, and can result in a significant loss of germplasm resources. To elucidate the immune response mechanism of C. nasus livers to Anisakidae infection, we collected and analysed 18 parasitic and 18 non-parasitic livers at gonadal developmental stages II, III, and V using histopathology, molecular biology and transcriptome methods. The hepatic portal area of the parasitic group exhibited an increase in the fibrous stroma and thickened hepatic arteries with positive Ly-6G staining, indicating inflammation and immune responses in the liver. Hepatocyte cytokine levels and the expression of liver function-related genes indicated that fish livers responded similarly to Anisakidae parasitism across different gonadal developmental stages. Oxidative stress indices showed more intense changes in stage II samples, whereas gene expression levels of Nrf2 and C3 were significantly increased in parasitised livers during stage III and V. Liver transcriptome sequencing identified 2575 differentially expressed genes between the parasitic and non-parasitic groups at the three gonadal developmental stages. KEGG pathway analysis showed that natural killer cell-mediated cytotoxicity, the NOD-like receptor signaling pathway, neutrophil extracellular trap formation, and other immune pathways were significantly enriched. Expression patterns varied across developmental stages, suggesting that innate immunity was primarily responsible for the liver immune response to Anisakidae infection during C. nasus migration, possibly related to water temperature changes or shifts in the gonadal developmental stage. In summary, this study investigated the immune response of C. nasus to Anisakidae parasitism under natural conditions, focusing on reproductive aspects and environmental changes, thereby establishing a foundation for elucidating the molecular mechanisms underlying the immune response of Anisakidae in C. nasus.

HSP90β shapes the fate of Th17 cells with the help of glycolysis-controlled methylation modification

BACKGROUND AND PURPOSE

Ulcerative colitis (UC) is a refractory inflammatory disease associated with immune dysregulation. Elevated levels of heat shock protein (HSP) 90 in the β but not α subtype were positively associated with disease status in UC patients. This study validated the possibility that pharmacological inhibition or reduction of HSP90β would alleviate colitis, induced by dextran sulfate sodium, in mice and elucidated its mechanisms.

EXPERIMENTAL APPROACH

Histopathological and biochemical analysis assessed disease severity, and bioinformatics and correlation analysis explained the association between the many immune cells and HSP90β. Flow cytometry was used to analyse the homeostasis and transdifferentiation of Th17 and Treg cells. In vitro inhibition and adoptive transfer assays were used to investigate functions of the phenotypically transformed Th17 cells. Metabolomic analysis, DNA methylation detection and chromatin immunoprecipitation were used to explore these mechanisms.

KEY RESULTS

The selective pharmacological inhibitor (HSP90βi) and shHSP90β significantly mitigated UC in mice and promoted transformation of Th17 to Treg cell phenotype, via Foxp3 transcription. The phenotypically-transformed Th17 cells by HSP90βi or shHSP90β were able to inhibit lymphocyte proliferation and colitis in mice. HSP90βi and shHSP90β selectively weakened glycolysis by stopping the direct association of HSP90β and GLUT1, the key glucose transporter, to accelerate ubiquitination degradation of GLUT1, and enhance the methylation of Foxp3 CNS2 region. Then, the mediator path was identified as the "lactate-STAT5-TET2" cascade.

CONCLUSION AND IMPLICATIONS

HSP90β shapes the fate of Th17 cells via glycolysis-controlled methylation modification to affect UC progression, which provides a new therapeutic target for UC.

Bioactive components in prunella vulgaris for treating Hashimoto's disease via regulation of innate immune response in human thyrocytes

Background

Hashimoto's thyroiditis (HT) is a thyroid autoimmune disease characterized by lymphocytic infiltration and thyroid destruction. Prunella vulgaris (PV) is a traditional Chinese herbal medicine with documented clinical efficacy in treating HT. We previously reported an immunoregulatory effect of PV in thyrocytes; however, the bioactive components of PV remained unclear. This study aimed to elucidate key components of PV for treating HT and their acting mechanisms.

Methods

Network pharmacology was used to predict key PV components for HT. The predicted components were tested to determine whether they could exert an immunoregulatory effect of PV in human thyrocytes. Limited proteolysis-mass spectrometry (Lip-MS) was used to explore interacting proteins with PV components in human thyrocytes. Microscale thermophoresis binding assay was used to evaluate the affinity of PV components with the target protein.

Results

Eleven PV components with 192 component targets and 3415 HT-related genes were gathered from public databases. With network pharmacology, a 'component-target-disease' network was established wherein four flavonoids including quercetin, luteolin, kaempferol, morin, and a phytosterol, β-sitosterol were predicted as key components in PV for HT. In stimulated primary human thyrocytes or Nthy-ori-31 cells, key components inhibited gene expressions of inflammatory cytokines including tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interferon-β (IFN-β), cellular apoptosis, and activation of nuclear factor κB (NF-κB) and interferon regulatory factor 3 (IRF-3). Heat shock protein 90 alpha, class A, member 1 (HSP90AA1), was identified to interact with flavonoids in PV by Lip-MS. Morin had the highest affinity with HSP90AA1 (KD = 122.74 μM), followed by kaempferol (KD = 168.53 μM), luteolin (KD = 293.94 μM), and quercetin (KD = 356.86 μM).

Conclusion

Quercetin, luteolin, kaempferol, morin, and β-sitosterol reproduced an anti-inflammatory and anti-apoptosis effect of PV in stimulated human thyrocytes, which potentially contributed to the treatment efficacy of PV in HT.

Intraperitoneal Administration of 17-DMAG as an Effective Treatment against Leishmania braziliensis Infection in BALB/c Mice: A Preclinical Study

BACKGROUND

Leishmaniasis is a significant global public health issue that is caused by parasites from Leishmania genus. With limited treatment options and rising drug resistance, there is a pressing need for new therapeutic approaches. Molecular chaperones, particularly Hsp90, play a crucial role in parasite biology and are emerging as promising targets for drug development.

OBJECTIVE

This study evaluates the efficacy of 17-DMAG in treating BALB/c mice from cutaneous leishmaniasis through in vitro and in vivo approaches.

MATERIALS AND METHODS

We assessed 17-DMAG's cytotoxic effect on bone marrow-derived macrophages (BMMΦ) and its effects against L. braziliensis promastigotes and intracellular amastigotes. Additionally, we tested the compound's efficacy in BALB/c mice infected with L. braziliensis via intraperitoneal administration to evaluate the reduction in lesion size and the decrease in parasite load in the ears and lymph nodes of infected animals.

RESULTS

17-DMAG showed selective toxicity [selective index = 432) towards Leishmania amastigotes, causing minimal damage to host cells. The treatment significantly reduced lesion sizes in mice and resulted in parasite clearance from ears and lymph nodes. It also diminished inflammatory responses and reduced the release of pro-inflammatory cytokines (IL-6, IFN-γ, TNF) and the regulatory cytokine IL-10, underscoring its dual leishmanicidal and anti-inflammatory properties.

CONCLUSIONS

Our findings confirm the potential of 17-DMAG as a viable treatment for cutaneous leishmaniasis and support further research into its mechanisms and potential applications against other infectious diseases.

Dual role of autoantibodies to heat shock proteins in autoimmune diseases

Autoimmune diseases are characterized by the recognition of self-antigens (autoantigens) by immune system cells. Loss of immunological tolerance may lead to the generation of autoantibodies and, consequently, tissue damage. It has already been proven that highly immunogenic bacterial and autologous extracellular heat shock proteins (eHsps) interact with immune cells of the innate and adaptive arms of the immune system. The latter interactions may stimulate a humoral (auto)immune response and lead to the generation of anti-Hsps (auto)antibodies. Although circulating levels of anti-Hsps autoantibodies are often elevated in patients suffering from multiple inflammatory and autoimmune diseases, their role in the development of pathological conditions is not fully established. This mini-review presents the dual role of anti-Hsps autoantibodies - protective or pathogenic - in the context of the development of selected autoimmune diseases.

Protective role of the HSP90 inhibitor, STA-9090, in lungs of SARS-CoV-2-infected Syrian golden hamsters

INTRODUCTION

The emergence of new SARS-CoV-2 variants, capable of escaping the humoral immunity acquired by the available vaccines, together with waning immunity and vaccine hesitancy, challenges the efficacy of the vaccination strategy in fighting COVID-19. Improved therapeutic strategies are urgently needed to better intervene particularly in severe cases of the disease. They should aim at controlling the hyperinflammatory state generated on infection, reducing lung tissue pathology and inhibiting viral replication. Previous research has pointed to a possible role for the chaperone HSP90 in SARS-CoV-2 replication and COVID-19 pathogenesis. Pharmacological intervention through HSP90 inhibitors was shown to be beneficial in the treatment of inflammatory diseases, infections and reducing replication of diverse viruses.

METHODS

In this study, we investigated the effects of the potent HSP90 inhibitor Ganetespib (STA-9090) in vitro on alveolar epithelial cells and alveolar macrophages to characterise its effects on cell activation and viral replication. Additionally, the Syrian hamster animal model was used to evaluate its efficacy in controlling systemic inflammation and viral burden after infection.

RESULTS

In vitro, STA-9090 reduced viral replication on alveolar epithelial cells in a dose-dependent manner and lowered significantly the expression of proinflammatory genes, in both alveolar epithelial cells and alveolar macrophages. In vivo, although no reduction in viral load was observed, administration of STA-9090 led to an overall improvement of the clinical condition of infected animals, with reduced oedema formation and lung tissue pathology.

CONCLUSION

Altogether, we show that HSP90 inhibition could serve as a potential treatment option for moderate and severe cases of COVID-19.

Regulation of Epithelial and Endothelial Barriers by Molecular Chaperones

The integrity and permeability of epithelial and endothelial barriers depend on the formation of tight junctions, adherens junctions, and a junction-associated cytoskeleton. The establishment of this junction-cytoskeletal module relies on the correct folding and oligomerization of its protein components. Molecular chaperones are known regulators of protein folding and complex formation in different cellular compartments. Mammalian cells possess an elaborate chaperone network consisting of several hundred chaperones and co-chaperones. Only a small part of this network has been linked, however, to the regulation of intercellular adhesions, and the systematic analysis of chaperone functions at epithelial and endothelial barriers is lacking. This review describes the functions and mechanisms of the chaperone-assisted regulation of intercellular junctions. The major focus of this review is on heat shock protein chaperones, their co-chaperones, and chaperonins since these molecules are the focus of the majority of the articles published on the chaperone-mediated control of tissue barriers. This review discusses the roles of chaperones in the regulation of the steady-state integrity of epithelial and vascular barriers as well as the disruption of these barriers by pathogenic factors and extracellular stressors. Since cytoskeletal coupling is essential for junctional integrity and remodeling, chaperone-assisted assembly of the actomyosin cytoskeleton is also discussed.

The dance of proteostasis and metabolism: Unveiling the caloristatic controlling switch

The heat shock response (HSR) is an ancient and evolutionarily conserved mechanism designed to restore cellular homeostasis following proteotoxic challenges. However, it has become increasingly evident that disruptions in energy metabolism also trigger the HSR. This interplay between proteostasis and energy regulation is rooted in the fundamental need for ATP to fuel protein synthesis and repair, making the HSR an essential component of cellular energy management. Recent findings suggest that the origins of proteostasis-defending systems can be traced back over 3.6 billion years, aligning with the emergence of sugar kinases that optimized glycolysis around 3.594 billion years ago. This evolutionary connection is underscored by the spatial similarities between the nucleotide-binding domain of HSP70, the key player in protein chaperone machinery, and hexokinases. The HSR serves as a hub that integrates energy metabolism and resolution of inflammation, further highlighting its role in maintaining cellular homeostasis. Notably, 5'-adenosine monophosphate-activated protein kinase emerges as a central regulator, promoting the HSR during predominantly proteotoxic stress while suppressing it in response to predominantly metabolic stress. The complex relationship between 5'-adenosine monophosphate-activated protein kinase and the HSR is finely tuned, with paradoxical effects observed under different stress conditions. This delicate equilibrium, known as caloristasis, ensures that cellular homeostasis is maintained despite shifting environmental and intracellular conditions. Understanding the caloristatic controlling switch at the heart of this interplay is crucial. It offers insights into a wide range of conditions, including glycemic control, obesity, type 2 diabetes, cardiovascular and neurodegenerative diseases, reproductive abnormalities, and the optimization of exercise routines. These findings highlight the profound interconnectedness of proteostasis and energy metabolism in cellular function and adaptation.

Heat shock protein 90 inhibition attenuates inflammation in models of atopic dermatitis: a novel mechanism of action

Background

Heat shock protein 90 (HSP90) is an important chaperone supporting the function of many proinflammatory client proteins. Recent studies indicate HSP90 inhibition may be a novel mechanism of action for inflammatory skin diseases; however, this has not been explored in atopic dermatitis (AD).

Objectives

Our study aimed to investigate HSP90 as a novel target to treat AD.

Methods

Experimental models of AD were used including primary human keratinocytes stimulated with cytokines (TNF/IFNγ or TNF/IL-4) and a mouse model established by MC903 applications.

Results

In primary human keratinocytes using RT-qPCR, the HSP90 inhibitor RGRN-305 strongly suppressed the gene expression of Th1- (TNF, IL1B, IL6) and Th2-associated (CCL17, CCL22, TSLP) cytokines and chemokines related to AD. We next demonstrated that topical and oral RGRN-305 robustly suppressed MC903-induced AD-like inflammation in mice by reducing clinical signs of dermatitis (oedema and erythema) and immune cell infiltration into the skin (T cells, neutrophils, mast cells). Interestingly, topical RGRN-305 exhibited similar or slightly inferior efficacy but less weight loss compared with topical dexamethasone. Furthermore, RNA sequencing of skin biopsies revealed that RGRN-305 attenuated MC903-induced transcriptome alterations, suppressing genes implicated in inflammation including AD-associated cytokines (Il1b, Il4, Il6, Il13), which was confirmed by RT-qPCR. Lastly, we discovered using Western blot that RGRN-305 disrupted JAK-STAT signaling by suppressing the activity of STAT3 and STAT6 in primary human keratinocytes, which was consistent with enrichment analyses from the mouse model.

Conclusion

HSP90 inhibition by RGRN-305 robustly suppressed inflammation in experimental models mimicking AD, proving that HSP90 inhibition may be a novel mechanism of action in treating AD.

Introducing Molecular Chaperones into the Causality and Prospective Management of Autoimmune Hepatitis

Molecular chaperones influence the immunogenicity of peptides and the activation of effector T cells, and their pathogenic roles in autoimmune hepatitis are unclear. Heat shock proteins are pivotal in the processing and presentation of peptides that activate CD8+ T cells. They can also induce regulatory B and T cells and promote immune tolerance. Tapasin and the transporter associated with antigen processing-binding protein influence the editing and loading of high-affinity peptides for presentation by class I molecules of the major histocompatibility complex. Their over-expression could enhance the autoimmune response, and their deficiency could weaken it. The lysosome-associated membrane protein-2a isoform in conjunction with heat shock cognate 70 supports the importation of cytosolic proteins into lysosomes. Chaperone-mediated autophagy can then process the peptides for activation of CD4+ T cells. Over-expression of autophagy in T cells may also eliminate negative regulators of their activity. The human leukocyte antigen B-associated transcript three facilitates the expression of class II peptide receptors, inhibits T cell apoptosis, prevents T cell exhaustion, and sustains the immune response. Immunization with heat shock proteins has induced immune tolerance in experimental models and humans with autoimmune disease by inducing regulatory T cells. Therapeutic manipulation of other molecular chaperones may promote T cell exhaustion and induce tolerogenic dendritic cells. In conclusion, molecular chaperones constitute an under-evaluated family of ancillary proteins that could affect the occurrence, severity, and outcome of autoimmune hepatitis. Clarification of their contributions to the immune mechanisms and clinical activity of autoimmune hepatitis could have therapeutic implications.

Heat shock protein 90 (Hsp90) inhibitor STA-9090 (Ganetespib) ameliorates inflammation in a mouse model of atopic dermatitis

Molecular chaperones belonging to the heat shock protein 90 (Hsp90) family are implicated in inflammatory processes and described as potential novel therapeutic targets in autoimmune/inflammatory skin diseases. While the pathological role of circulating Hsp90 has been recently proposed in patients with atopic dermatitis (AD), a chronic inflammatory skin disease characterized by intense itching and recurrent skin lesions, studies aimed at investigating the role of Hsp90 as a potential target of AD therapy have not yet been conducted. Here, the effects of the Hsp90 blocker STA-9090 (Ganetespib) applied systemically or topically were determined in an experimental mouse model of dinitrochlorobenzene (DNCB)-induced AD. Intraperitoneal administration of STA-9090 ameliorated clinical disease severity, histological epidermal thickness, and dermal leukocyte infiltration in AD mice which was associated with reducing the scratching behavior in DNCB-treated animals. Additionally, topically applied STA-9090 led to lowered disease activity in AD mice, reduced serum levels of IgE, and up-regulated filaggrin expression in lesional skin samples. Our observations suggest that Hsp90 may be a promising therapeutic target in atopic dermatitis and potentially other inflammatory or autoimmune dermatoses.

Acute toxicological evaluation of AT-533 and AT-533 gel in Sprague-Dawley rats

BACKGROUND

AT-533 is a novel heat shock protein 90 inhibitor that exerting anti-inflammatory, antiviral, and antitumor efficacy. Furthermore, the gel made of AT-533 as raw material named AT-533 gel has the function of repairing keratitis and dermatitis caused by herpes virus infection. However, the acute safety evaluation of AT-533 and AT-533 gel has not been conducted.

METHODS AND RESULTS

Herein, we performed acute toxicological studies of AT-533 and AT-533 gel in Sprague-Dawley rats. Fifteen-day acute toxicity study of AT-533 was conducted in both male and female Sprague-Dawley rats at doses of 5, 50, 250 and 500 mg/kg and AT-533 gel at 5 g/kg in the study. During experiment, food consumption and mortality were observed and body weight, hematology, serum biochemistry and histopathological assessment of rats were carried out. No abnormal changes were observed in rats percutaneously treated with AT-533 at 5 mg/kg and 50 mg/kg and AT-533 gel. However, loss of appetite and body weight, adverse reactions, toxicologically relevant alterations in hematology and biochemistry were found in rats percutaneously treated with AT-533 at 250 mg/kg and 500 mg/kg during 15-day acute dermic toxicity study.

CONCLUSIONS

The aforementioned results suggested that the LD50 of AT-533 is 228.382 mg/kg and the LD50 of AT-533 gel is greater than 5 g/kg. These findings indicated that AT-533 is non-toxic in rats when the dose less than 50 mg/kg and AT-533 gel can be considered a gel with no toxicity at doses less than 5 g/kg.

Biomarkers and biologics related with psoriasis and psoriatic arthritis

Over the past half century, psoriasis is considered as an immune-mediated inflammatory skin disease with the combined hallmarks of autoimmunity and autoinflammation, according to growing volumes of clinical and experimental findings. There is currently no cure for psoriasis, current treatment strategies focus on symptom control, disease minimization, and patient's quality of life enhancement. To meet these challenges, it keeps imperative to discover potential biomarkers, so that not only can they be used for the prediction and monitoring of psoriasis disease in clinic, but also can provide novel therapeutic targets or treatment strategies for psoriasis sufferers. This review systematically demonstrates the research progress of psoriasis-related biomarkers and elaborates their related mechanisms in the pathological development of psoriasis and psoriatic arthritis. In addition, we summarize the development of biologic therapies for psoriasis and psoriatic arthritis in order to drive the broader discussion of psoriasis as an autoimmune-mediated inflammatory skin disease.

Prediction and verification of the active ingredients and potential targets of Erhuang Quzhi Granules on non-alcoholic fatty liver disease based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Erhuang Quzhi Granules (EQG) is a compound composed of 13 traditional Chinese medicines developed by the First Affiliated Hospital of Shihezi University. In clinical practice, EQG has been applied to the treatment of hyperlipidemia and non-alcoholic fatty liver disease (NAFLD), and could significantly improve the serum biochemical indicators of NAFLD patients.

AIM OF THE STUDY

This study aims to explore the bioactive compounds, potential targets, and molecular mechanisms of EQG against NAFLD through network pharmacology, molecular docking, and experimental verification.

MATERIALS AND METHODS

The chemical components of EQG came from the literature and quality standard. Bioactive compounds were screened based on the absorption, distribution, metabolism, and excretion (ADME) feature, and their potential targets were predicted using the substructure-drug-target network-based inference (SDTNBI). The core targets and signaling pathways were obtained through the analysis of protein-protein interaction (PPI), gene ontology (GO) function, and Kyoto encyclopedia of genes and genomes (KEGG) pathway. The results were further confirmed by literature retrieval, molecular docking, and in vivo experiments.

RESULTS

The results of network pharmacology showed 12 active ingredients and 10 core targets for EQG in treating NAFLD. And EQG mainly regulates lipid and atherosclerosis-related pathways to improve NAFLD. The collected literature verified the regulatory effect of the active components of EQG on core targets TP53, PPARG, EGFR, HIF1A, PPARA, and MTOR. Molecular docking results showed that Aloe-Emodin (AE), Emodin, Physcion, and Rhein (RH) had stable binding structures with the core targets HSP90AA1. In vivo experiment showed that AE and RH reduced aspartate transaminase (AST), alanine aminotransferase (ALT), interleukin (IL)-1β, IL-6, IL18, and tumor necrosis factor α (TNF-α) in the serum or liver of NAFLD mice, improved liver lipid deposition and fibrosis, and inhibit gene expression of nuclear factor kappa B (NF-κB), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), IL-1β, TNF-α and protein expression of HSP90, NF-κB and Cleaved caspase-1.

CONCLUSIONS

This study comprehensively revealed the biological compounds, potential targets, and molecular mechanisms of EQG in the treatment of NAFLD, providing a reference basis for the promotion of EQG in the clinic.

TRPA1 activation and Hsp90 inhibition synergistically downregulate macrophage activation and inflammatory responses in vitro

BACKGROUND

Transient receptor potential ankyrin 1 (TRPA1) channels are known to be actively involved in various pathophysiological conditions, including neuronal inflammation, neuropathic pain, and various immunological responses. Heat shock protein 90 (Hsp90), a cytoplasmic molecular chaperone, is well-reported for various cellular and physiological processes. Hsp90 inhibition by various molecules has garnered importance for its therapeutic significance in the downregulation of inflammation and are proposed as anti-cancer drugs. However, the possible role of TRPA1 in the Hsp90-associated modulation of immune responses remains scanty.

RESULTS

Here, we have investigated the role of TRPA1 in regulating the anti-inflammatory effect of Hsp90 inhibition via 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) in lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA) stimulation in RAW 264.7, a mouse macrophage cell lines and PMA differentiated THP-1, a human monocytic cell line similar to macrophages. Activation of TRPA1 with Allyl isothiocyanate (AITC) is observed to execute an anti-inflammatory role via augmenting Hsp90 inhibition-mediated anti-inflammatory responses towards LPS or PMA stimulation in macrophages, whereas inhibition of TRPA1 by 1,2,3,6-Tetrahydro-1,3-dimethyl-N-[4-(1-methylethyl)phenyl]-2,6-dioxo-7 H-purine-7-acetamide,2-(1,3-Dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7 H-purin-7-yl)-N-(4-isopropylphenyl)acetamide (HC-030031) downregulates these developments. LPS or PMA-induced macrophage activation was found to be regulated by TRPA1. The same was confirmed by studying the levels of activation markers (major histocompatibility complex II (MHCII), cluster of differentiation (CD) 80 (CD80), and CD86, pro-inflammatory cytokines (tumor necrosis factor (TNF) and interleukin 6 (IL-6)), NO (nitric oxide) production, differential expression of mitogen-activated protein kinase (MAPK) signaling pathways (p-p38 MAPK, phospho-extracellular signal-regulated kinase 1/2 (p-ERK 1/2), and phosphor-stress-activated protein kinase/c-Jun N-terminal kinase (p-SAPK/JNK)), and induction of apoptosis. Additionally, TRPA1 has been found to be an important contributor to intracellular calcium levels toward Hsp90 inhibition in LPS or PMA-stimulated macrophages.

CONCLUSION

This study indicates a significant role of TRPA1 in Hsp90 inhibition-mediated anti-inflammatory developments in LPS or PMA-stimulated macrophages. Activation of TRPA1 and inhibition of Hsp90 has synergistic roles towards regulating inflammatory responses associated with macrophages. The role of TRPA1 in Hsp90 inhibition-mediated modulation of macrophage responses may provide insights towards designing future novel therapeutic approaches to regulate various inflammatory responses.

Shear stress induces monocyte/macrophage-mediated inflammation by upregulating cell-surface expression of heat shock proteins

The loss of endothelial cells is associated with the accumulation of monocytes/macrophages underneath the surface of the arteries, where cells are prone to mechanical stimulation, such as shear stress. However, the impact of mechanical stimuli on monocytic cells remains unclear. To assess whether mechanical stress affects monocytic cell function, we examined the expression of inflammatory molecules and surface proteins, whose levels changed following shear stress in human THP-1 cells. Shear stress increased the inflammatory chemokine CCL2, which enhanced the migration of monocytic cells and tumor necrosis factor (TNF)-α and interleukin (IL)- 1β at transcriptional and protein levels. We identified that the surface levels of heat shock protein 70 (HSP70), HSP90, and HSP105 increased using mass spectrometry-based proteomics, which was confirmed by western blot analysis, flow cytometry, and immunofluorescence. Treatment with HSP70/HSP105 and HSP90 inhibitors suppressed the expression and secretion of CCL2 and monocytic cell migration, suggesting an association between HSPs and inflammatory responses. We also demonstrated the coexistence and colocalization of increased HSP90 immunoreactivity and CD68 positive cells in atherosclerotic plaques of ApoE deficient mice fed a high-fat diet and human femoral artery endarterectomy specimens. These results suggest that monocytes/macrophages affected by shear stress polarize to a pro-inflammatory phenotype and increase surface protein levels involved in inflammatory responses. The regulation of the abovementioned HSPs upregulated on the monocytes/macrophages surface may serve as a novel therapeutic target for inflammation due to shear stress.

Status Quo and Future Perspectives of Molecular and Genomic Studies on the Genus Biomphalaria-The Intermediate Snail Host of Schistosoma mansoni

Schistosomiasis, or also generally known as bilharzia or snail fever, is a parasitic disease that is caused by trematode flatworms of the genus Schistosoma. It is considered by the World Health Organisation as the second most prevalent parasitic disease after malaria and affects more than 230 million people in over 70 countries. People are infected via a variety of activities ranging from agricultural, domestic, occupational to recreational activities, where the freshwater snails Biomphalaria release Schistosoma cercariae larvae that penetrate the skin of humans when exposed in water. Understanding the biology of the intermediate host snail Biomphalaria is thus important to reveal the potential spread of schistosomiasis. In this article, we present an overview of the latest molecular studies focused on the snail Biomphalaria, including its ecology, evolution, and immune response; and propose using genomics as a foundation to further understand and control this disease vector and thus the transmission of schistosomiasis.

Heat shock protein 90 inhibitor RGRN-305 potently attenuates skin inflammation

Introduction

Chronic inflammatory skin diseases may have a profound negative impact on the quality of life. Current treatment options may be inadequate, offering an unsatisfactory response or side effects. Therefore, ongoing efforts exist to identify novel effective and safe treatments. Heat shock protein (HSP) 90 is a chaperone that promotes the activity of a wide range of client proteins including key proinflammatory molecules involved in aberrant inflammation. Recently, a proof-of-concept clinical trial of 13 patients suggested that RGRN-305 (an HSP90 inhibitor) may be an oral treatment for psoriasis. However, HSP90 inhibition may be a novel therapeutic approach extending beyond psoriasis to include multiple immune-mediated inflammatory skin diseases.

Methods

This study aimed to investigate (i) the anti-inflammatory effects and mechanisms of HSP90 inhibition and (ii) the feasibility of topical RGRN-305 administration (new route of administration) in models of inflammation elicited by 12-O-tetradecanoylphorbol-13-acetate (TPA) in primary human keratinocytes and mice (irritative dermatitis murine model).

Results/Discussion

In primary human keratinocytes stimulated with TPA, a Nanostring® nCounter gene expression assay demonstrated that HSP90 inhibition with RGRN-305 suppressed many proinflammatory genes. Furthermore, when measured by quantitative real-time polymerase chain reaction (RT-qPCR), RGRN-305 significantly reduced the gene expression of TNF, IL1B, IL6 and CXCL8. We next demonstrated that topical RGRN-305 application significantly ameliorated TPA-induced skin inflammation in mice. The increase in ear thickness (a marker of inflammation) was significantly reduced (up to 89% inhibition). In accordance, RT-qPCR of the ear tissue demonstrated that RGRN-305 robustly reduced the gene expression of proinflammatory markers (Tnf, Il1b, Il6, Il17A and Defb4). Moreover, RNA sequencing revealed that RGRN-305 mitigated TPA-induced alterations in gene expression and suppressed genes implicated in inflammation. Lastly, we discovered that the anti-inflammatory effects were mediated, at least partly, by suppressing the activity of NF-κB, ERK1/2, p38 MAPK and c-Jun signaling pathways, which are consistent with previous findings in other experimental models beyond skin inflammation. In summary, HSP90 inhibition robustly suppressed TPA-induced inflammation by targeting key proinflammatory cytokines and signaling pathways. Our findings suggest that HSP90 inhibition may be a novel mechanism of action for treating immune-mediated skin disease beyond psoriasis, and it may be a topical treatment option.

Hsp90 as a Myokine: Its Association with Systemic Inflammation after Exercise Interventions in Patients with Myositis and Healthy Subjects

Compelling evidence supports the health benefits of physical exercise on the immune system, possibly through the molecules secreted by the skeletal muscles known as myokines. Herein, we assessed the impact of exercise interventions on plasma Heat shock protein 90 (Hsp90) levels in 27 patients with idiopathic inflammatory myopathies (IIM) compared with 23 IIM patients treated with standard-of-care immunosuppressive therapy only, and in 18 healthy subjects undergoing strenuous eccentric exercise, and their associations with the traditional serum markers of muscle damage and inflammation. In contrast to IIM patients treated with pharmacotherapy only, in whom we demonstrated a significant decrease in Hsp90 over 24 weeks, the 24-week exercise program resulted in a stabilization of Hsp90 levels. These changes in Hsp90 levels were associated with changes in several inflammatory cytokines/chemokines involved in the pathogenesis of IIM or muscle regeneration in general. Strenuous eccentric exercise in healthy volunteers induced a brief increase in Hsp90 levels with a subsequent return to baseline levels at 14 days after the exercise, with less pronounced correlations to systemic inflammation. In this study, we identified Hsp90 as a potential myokine and mediator for exercise-induced immune response and as a potential biomarker predicting improvement after physiotherapy in muscle endurance in IIM.

Heat Shock Protein 90 (Hsp90) and Hsp70 as Potential Therapeutic Targets in Autoimmune Skin Diseases

Over a hundred different autoimmune diseases have been described to date, which can affect every organ in the body, including the largest one, the skin. In fact, up to one-fifth of the world's population suffers from chronic, noninfectious inflammatory skin diseases, the development of which is significantly influenced by an autoimmune response. One of the hallmarks of autoimmune diseases is the loss of immune tolerance, which leads to the formation of autoreactive lymphocytes or autoantibodies and, consequently, to chronic inflammation and tissue damage. The treatment of autoimmune skin diseases mainly focuses on immunosuppression (using, e.g., corticosteroids) but almost never leads to the development of permanent mechanisms of immune tolerance. In addition, current therapies and their long-term administration may cause serious adverse effects. Hence, safer and more effective therapies that bring sustained balance between pro- and anti-inflammatory responses are still desired. Both intra- and extracellular heat shock proteins (Hsps), specifically well-characterized inducible Hsp90 and Hsp70 chaperones, have been highlighted as therapeutic targets for autoimmune diseases. This review presents preclinical data on the involvement of Hsp90 and Hsp70 in modulating the immune response, specifically in the context of the treatment of selected autoimmune skin diseases with emphasis on autoimmune bullous skin diseases and psoriasis.

The Effects of Cannabinoid Agonist, Heat Shock Protein 90 and Nitric Oxide Synthase Inhibitors on Increasing IL-13 and IL-31 Levels in Chronic Pruritus

BACKGROUND

Heat shock protein 90 (Hsp90) inhibitor and cannabinoid agonists ameliorate dry skin-induced chronic itch. We have recently reported that cannabinoids, hsp90 and nitric oxide (NO) are involved in dry skin-induced itch. Here, we investigated the contribution of the Th2 cell signaling pathway to the antipruritic effect of the hsp90 inhibitor 17-Alilamino-17-demethoxygeldanamycin (17-AAG), nitric oxide synthase (NOS) inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and cannabinoid agonist WIN 55,212-2 on a dry skin-induced scratch.

METHODS

Dry skin-induced chronic itching was created by topical application of AEW (acetone/diethyl ether/water). WIN 55,212-2 (1 mg/kg, i.p.), L-NAME (1 mg/kg, i.p.) and increasing doses of 17-AAG (1, 3 and 5 mg/kg,i.p.) were administered to Balb/c mice (for each group, n = 6). After these applications, skin tissues were taken from the nape region of all of the mice. Gene and protein expressions of IL-13 and IL-31 were evaluated in skin tissues by RT-PCR and immunohistochemistry, respectively.

RESULTS

IL-13 and IL-31 mRNA expressions and immune positive cell counts were increased in the AEW applied groups. WIN 55,212-2 reduced both of the increased cytokines levels, while L-NAME decreased only the IL-13. 17-AAG dose-dependently reduced the increased cytokine levels. IL-13 and IL-31 levels significantly decreased following the co-administration of these agents.

CONCLUSION

These results show that increased levels of IL-13 and IL-31 are associated with pruritus. Hsp90 inhibition and cannabinoid system activation may induce antipruritic effects through down-regulation of these cytokines.

The Role of TNF-α and Its Target HSP-70 in Triggering Apoptosis in Normozoospermic and Non-Normozoospermic Samples

Objective: Semen analysis is performed as one of the screening tests for infertility, including motility, morphology, and concentration observation. We aimed to investigate the expression rates of tumor necrosis factor-α (TNF-α) and heat shock protein (HSP)-70 as two opposite affectors of apoptosis in men with normal semen parameters and abnormal parameters to find the possible effect of this pathway on sperm parameters. We also aimed to investigate the apoptotic markers (DNA fragmentation and Caspase-3 expression) to observe the correlation of this pathway with apoptosis. Materials and Methods: A total of 32 men who applied for infertility evaluation were included in the study. Semen analysis was performed according to WHO criteria. Liquefaction time, appearance, volume, pH, viscosity, sperm concentration, total motility rate, sperm motility, and percentage of spermatozoa with normal morphology were determined. TNF-α, HSP-70, and Caspase-3 immunolocalization were scored histologically. A sperm chromatin dispersion test was used to observe DNA fragmentation. Results: There was no significant difference in TNF-α protein expression rate (mild level). The HSP-70 expression rate was lower, especially in the head region of normo. Caspase-3 was higher totally in non-normo. DNA fragmentation levels were similar in both the groups. Conclusion: From TNF-α protein expression at the mild level in both the groups, it may be hypothesized that the apoptotic pathway might not be triggered by the extrinsic pathway. We found a negative correlation between HSP-70 and Caspase-3 expressions, providing further evidence that HSP-70 works as an inhibitor to apoptosis. This, particularly on specific points, made us think the communication might begin in the anterior chamber, then flow through the cell body to the tail. HSP-70 expression was lower in normo than in non-normo, indicating the possible role of HSP-70 as an answer to any type of stressor in non-normozoospermic patients. Correspondingly, it may be concluded that HSP has an antiapoptotic effect, causing inhibition in the elimination of abnormal sperm cells impairing sperm parameters.

The Keap1 signaling in the regulation of HSP90 pathway

The Keap1 protein is the master modulator of Nrf2 pathway; moreover, it is the hub of such important processes as cancer, cell stress, inflammation, and chemio- and radio-resistance. That is why Keap1 has become an intriguing pharmacological target. Many recent data show that Keap1 interacts with HSP90 protein. In this study, we use ferulic acid (FA) as antioxidant and anti-inflammatory agent, able to relieve inflammatory response. It is known that treatment with 100 μg of FA can significantly decrease the oxidative stress, so it turns to be useful to study the antioxidant regulation. The RAW 264.7 cells transfected with si-Keap1 and LPS treated are the in vitro model used to study the effects of Keap1 silencing on HSP90 activities and the FA antioxidant modulation. Immunoblot data and qPCR analysis show that Keap1 is involved in HSP90 modulation and on anti-oxidative response. Keap1 silencing affects negatively COX2 activation; in fact western blot and qPCR analysis conducted on RAW 264.7 cells Keap1silenced highlight that LPS treatment does not induce COX2 activation. In addition, the FA anti-oxidative and modulatory effect is abolished in COX2 pathway. The same results are point out using human A549 cell line with an allelic mutation on Keap1 gene, and the protein results are partially inactive. This preliminary study points out that Keap1protein is involved in HSP90 and anti-oxidative pathway regulation.

Heat Shock Proteins Alterations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease characterized by the attack of the immune system on the body's healthy joint lining and degeneration of articular structures. This disease involves an increased release of inflammatory mediators in the affected joint that sensitize sensory neurons and create a positive feedback loop to further enhance their release. Among these mediators, the cytokines and neuropeptides are responsible for the crippling pain and the persistent neurogenic inflammation associated with RA. More importantly, specific proteins released either centrally or peripherally have been shown to play opposing roles in the pathogenesis of this disease: an inflammatory role that mediates and increases the severity of inflammatory response and/or an anti-inflammatory and protective role that modulates the process of inflammation. In this review, we will shed light on the neuroimmune function of different members of the heat shock protein (HSPs) family and the complex manifold actions that they exert during the course of RA. Specifically, we will focus our discussion on the duality in the mechanism of action of Hsp27, Hsp60, Hsp70, and Hsp90.

HSP90 Inhibitor 17-AAG Attenuates Nucleus Pulposus Inflammation and Catabolism Induced by M1-Polarized Macrophages

Overactivated inflammation and catabolism induced by proinflammatory macrophages are involved in the pathological processes of intervertebral disc (IVD) degeneration (IVDD). Our previous study suggested the protective role of inhibiting heat shock protein 90 (HSP90) in IVDD, while the underlying mechanisms need advanced research. The current study investigated the effects of HSP90 inhibitor 17-AAG on nucleus pulposus (NP) inflammation and catabolism induced by M1-polarized macrophages. Immunohistochemical staining of degenerated human IVD samples showed massive infiltration of macrophages, especially M1 phenotype, as well as elevated levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMP)13. The conditioned medium (CM) of inflamed NP cells (NPCs) enhanced M1 polarization of macrophages, while the CM of M1 macrophages but not M2 macrophages promoted the expression of inflammatory factors and matrix proteases in NPCs. Additionally, we found that 17-AAG could represent anti-inflammatory and anti-catabolic effects by modulating both macrophages and NPCs. On the one hand, 17-AAG attenuated the pro-inflammatory activity of M1 macrophages via inhibiting nuclear factor-κB (NF-κB) pathway and mitogen-activated protein kinase (MAPK) pathways. On the other hand, 17-AAG dampened M1-CM-induced inflammation and catabolism in NPCs by upregulating HSP70 and suppressing the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) pathway. Moreover, both in vitro IVD culture models and murine disc puncture models supported that 17-AAG treatment decreased the levels of inflammatory factors and matrix proteases in IVD tissues. In conclusion, HSP90 inhibitor 17-AAG attenuates NP inflammation and catabolism induced by M1 macrophages, suggesting 17-AAG as a promising candidate for IVDD treatment.

Identification and Functional Analysis of the Regulatory Elements in the pHSPA6 Promoter

Functional and expressional research of heat shock protein A6 (HSPA6) suggests that the gene is of great value for neurodegenerative diseases, biosensors, cancer, etc. Based on the important value of pigs in agriculture and biomedicine and to advance knowledge of this little-studied HSPA member, the stress-sensitive sites in porcine HSPA6 (pHSPA6) were investigated following different stresses. Here, two heat shock elements (HSEs) and a conserved region (CR) were identified in the pHSPA6 promoter by a CRISPR/Cas9-mediated precise gene editing strategy. Gene expression data showed that sequence disruption of these regions could significantly reduce the expression of pHSPA6 under heat stress. Stimulation studies indicated that these regions responded not only to heat stress but also to copper sulfate, MG132, and curcumin. Further mechanism studies showed that downregulated pHSPA6 could significantly affect some important members of the HSP family that are involved in HSP40, HSP70, and HSP90. Overall, our results provide a new approach for investigating gene expression and regulation that may contribute to gene regulatory mechanisms, drug target selection, and breeding stock selection.

HSP90 inhibitor RGRN-305 for oral treatment of plaque type psoriasis: efficacy, safety and biomarker results in an open-label proof-of-concept study

BACKGROUND

HSP90 is a downstream regulator of tumor necrosis factor α (TNFα) and interleukin (IL)-17A signaling and may therefore serve as a novel target in the treatment of psoriasis.

OBJECTIVE

This phase 1b proof-of-concept study was undertaken to evaluate the safety and efficacy of a novel HSP90 inhibitor (RGRN-305) in the treatment of plaque psoriasis.

METHODS

An open-label, single-arm, dose-selection, single-center proof-of-concept study. Patients with plaque psoriasis were treated with 250 mg or 500 mg RGRN-305 daily for 12 weeks. Efficacy was evaluated clinically using Psoriasis Area and Severity Index (PASI), body surface area (BSA), and Physician Global Assessment (PGA) scores and by Dermatology Life Quality Index (DLQI). Skin biopsies collected at baseline and at 4, 8, and 12 weeks after treatment start were used for immunohistochemical staining and for gene expression analysis. Safety was monitored via laboratory tests, vital signs, ECG, and physical examinations.

RESULTS

Six of the eleven patients completing the study responded to RGRN-305 with a PASI improvement between 71% and 94%, whereas five patients were considered nonresponders with a PASI response < 50%. No severe adverse events were reported. Four of seven patients treated with 500 mg RGRN-305 daily experienced a mild to moderate exanthematous drug induced eruption due to study treatment. Two patients chose to discontinue the study due to this exanthematous eruption. RGRN-305 treatment resulted in pronounced inhibition of the IL-23, TNFα, and IL-17A signaling pathways and normalization of both histological changes and psoriatic lesion gene expression profiles in patients responding to treatment.

CONCLUSION

Treatment with RGRN-305 showed an acceptable safety, especially in the low-dose group, and was associated with clinically meaningful improvement in a subset of patients with plaque psoriasis, indicating that HSP90 may serve as a novel future target in psoriasis treatment.

Evidence for a role of extracellular heat shock protein 70 in epidermolysis bullosa acquisita

Heat shock protein 90 (Hsp90) and Hsp70 are chaperones implicated in different inflammatory disorders, given their property to impact innate and adaptive immune responses. Here, we determined the so far unknown role of extracellular Hsp70 in epidermolysis bullosa acquisita (EBA), an anti-type VII collagen autoantibody-mediated blistering dermatosis. The in vivo pathophysiological relevance of extracellular Hsp70 was demonstrated in an anti-type VII collagen antibody transfer-induced EBA mouse model in which elevated blood levels of this chaperone were recorded. We found that Hsp70-treated mice had a more intense clinical disease severity compared to controls that were paralleled by increased levels of cutaneous matrix metalloproteinase 9 and plasma hydrogen peroxide. The latter finding was confirmed in an independent reactive oxygen species release assay using EBA-specific immune complexes combined with recombinant Hsp70. Finally, cell culture experiments using human naive peripheral blood mononuclear cells (PBMC) revealed that extracellular Hsp70 stimulated the secretion of the T cell-derived pro-inflammatory cytokines IL-6 and IL-8. This work extends knowledge about the role of Hsps in autoimmune bullous diseases, suggesting that extracellular Hsp70 represents a pathophysiological factor and potential treatment target in EBA.

Circulating heat shock protein 90 (Hsp90) and autoantibodies to Hsp90 are increased in patients with atopic dermatitis

Atopic dermatitis (AD) is one of the most common chronic inflammatory dermatoses characterized by persistent itching and recurrent eczematous lesions. While the primary events and key drivers of AD are topics of ongoing debate, cutaneous inflammation due to inappropriate IgE (auto)antibody-related immune reactions is frequently considered. Highly conserved and immunogenic heat shock protein 90 (Hsp90), a key intra- and extracellular chaperone, can activate the immune response driving the generation of circulating anti-Hsp90 autoantibodies that are found to be elevated in several autoimmune disorders. Here, for the first time, we observed that serum levels of Hsp90 and anti-Hsp90 IgE autoantibodies are significantly elevated (p < 0.0001) in AD patients (n = 29) when compared to age- and gender-matched healthy controls (n = 70). We revealed a positive correlation (0.378, p = 0.042) between serum levels of Hsp90 and the severity of AD assessed by Scoring Atopic Dermatitis (SCORAD). In addition, seropositivity for anti-Hsp90 IgE has been found in 48.27% of AD patients and in 2.85% of healthy controls. Although further studies on a larger group of patients are needed to confirm presented data, our results suggest that extracellular Hsp90 and autoantibodies to Hsp90 deserve attention in the study of the mechanisms that promote the development and/or maintenance of atopic dermatitis.

Role of Heat Shock Proteins (HSP70 and HSP90) in Viral Infection

Heat shock proteins (HSPs) are a large group of chaperones found in most eukaryotes and bacteria. They are responsible for the correct protein folding, protection of the cell against stressors, presenting immune and inflammatory cytokines; furthermore, they are important factors in regulating cell differentiation, survival and death. Although the biological function of HSPs is to maintain cell homeostasis, some of them can be used by viruses both to fold their proteins and increase the chances of survival in unfavorable host conditions. Folding viral proteins as well as replicating many different viruses are carried out by, among others, proteins from the HSP70 and HSP90 families. In some cases, the HSP70 family proteins directly interact with viral polymerase to enhance viral replication or they can facilitate the formation of a viral replication complex and/or maintain the stability of complex proteins. It is known that HSP90 is important for the expression of viral genes at both the transcriptional and the translational levels. Both of these HSPs can form a complex with HSP90 and, consequently, facilitate the entry of the virus into the cell. Current studies have shown the biological significance of HSPs in the course of infection SARS-CoV-2. A comprehensive understanding of chaperone use during viral infection will provide new insight into viral replication mechanisms and therapeutic potential. The aim of this study is to describe the molecular basis of HSP70 and HSP90 participation in some viral infections and the potential use of these proteins in antiviral therapy.

Extracellular Heat Shock Proteins as Therapeutic Targets and Biomarkers in Fibrosing Interstitial Lung Diseases

Interstitial lung diseases (ILDs) include a large number of diseases and causes with variable outcomes often associated with progressive fibrosis. Although each of the individual fibrosing ILDs are rare, collectively, they affect a considerable number of patients, representing a significant burden of disease. Idiopathic pulmonary fibrosis (IPF) is the typical chronic fibrosing ILD associated with progressive decline in lung. Other fibrosing ILDs are often associated with connective tissues diseases, including rheumatoid arthritis-ILD (RA-ILD) and systemic sclerosis-associated ILD (SSc-ILD), or environmental/drug exposure. Given the vast number of progressive fibrosing ILDs and the disparities in clinical patterns and disease features, the course of these diseases is heterogeneous and cannot accurately be predicted for an individual patient. As a consequence, the discovery of novel biomarkers for these types of diseases is a major clinical challenge. Heat shock proteins (HSPs) are molecular chaperons that have been extensively described to be involved in fibrogenesis. Their extracellular forms (eHSPs) have been recently and successfully used as therapeutic targets or circulating biomarkers in cancer. The current review will describe the role of eHSPs in fibrosing ILDs, highlighting the importance of these particular stress proteins to develop new therapeutic strategies and discover potential biomarkers in these diseases.

Anti-Inflammatory Effects of RTD-1 in a Murine Model of Chronic Pseudomonas aeruginosa Lung Infection: Inhibition of NF-κB, Inflammasome Gene Expression, and Pro-IL-1β Biosynthesis

Vicious cycles of chronic airway obstruction, lung infections with Pseudomonas aeruginosa, and neutrophil-dominated inflammation contribute to morbidity and mortality in cystic fibrosis (CF) patients. Rhesus theta defensin-1 (RTD-1) is an antimicrobial macrocyclic peptide with immunomodulatory properties. Our objective was to investigate the anti-inflammatory effect of RTD-1 in a murine model of chronic P. aeruginosa lung infection. Mice received nebulized RTD-1 daily for 6 days. Bacterial burden, leukocyte counts, and cytokine concentrations were evaluated. Microarray analysis was performed on bronchoalveolar lavage fluid (BALF) cells and lung tissue homogenates. In vitro effects of RTD-1 in THP-1 cells were assessed using quantitative reverse transcription PCR, enzyme-linked immunosorbent assays, immunoblots, confocal microscopy, enzymatic activity assays, and NF-κB-reporter assays. RTD-1 significantly reduced lung white blood cell counts on days 3 (-54.95%; p = 0.0003) and 7 (-31.71%; p = 0.0097). Microarray analysis of lung tissue homogenates and BALF cells revealed that RTD-1 significantly reduced proinflammatory gene expression, particularly inflammasome-related genes (nod-like receptor protein 3, Mediterranean fever gene, interleukin (IL)-1α, and IL-1β) relative to the control. In vitro studies demonstrated NF-κB activation was reduced two-fold (p ≤ 0.0001) by RTD-1 treatment. Immunoblots revealed that RTD-1 treatment inhibited proIL-1β biosynthesis. Additionally, RTD-1 treatment was associated with a reduction in caspase-1 activation (FC = -1.79; p = 0.0052). RTD-1 exhibited potent anti-inflammatory activity in chronically infected mice. Importantly, RTD-1 inhibits inflammasome activity, which is possibly a downstream effect of NF-κB modulation. These findings support that this immunomodulatory peptide may be a promising therapeutic for CF-associated lung disease.

Induction of oxidative stress and apoptosis in the injured brain: potential relevance to brain regeneration in zebrafish

Recent findings suggest a significant role of the brain-derived neurotrophic factor (BDNF) as a mediator of brain regeneration following a stab injury in zebrafish. Since BDNF has been implicated in many physiological processes, we hypothesized that these processes are affected by brain injury in zebrafish. Hence, we examined the impact of stab injury on oxidative stress and apoptosis in the adult zebrafish brain. Stab wound injury (SWI) was induced in the right telencephalic hemisphere of the adult zebrafish brain and examined at different time points. The biochemical variables of oxidative stress insult and transcript levels of antioxidant genes were assessed to reflect upon the oxidative stress levels in the brain. Immunohistochemistry was performed to detect the levels of early apoptotic marker protein cleaved caspase-3, and the transcript levels of pro-apoptotic and anti-apoptotic genes were examined to determine the effect of SWI on apoptosis. The activity of antioxidant enzymes, the level of lipid peroxidation (LPO) and reduced glutathione (GSH) were significantly increased in the injured fish brain. SWI also enhanced the expression of cleaved caspase-3 protein and apoptosis-related gene transcripts. Our results indicate induction of oxidative stress and apoptosis in the telencephalon of adult zebrafish brain by SWI. These findings contribute to the overall understanding of the pathophysiology of traumatic brain injury and adult neurogenesis in the zebrafish model and raise new questions about the compensatory physiological mechanisms in response to traumatic brain injury in the adult zebrafish brain.

The Therapeutic Effect of Ge-Gen Decoction on a Rat Model of Primary Dysmenorrhea: Label-Free Quantitative Proteomics and Bioinformatic Analyses

Ge-Gen decoction (GGD) is widely used for the treatment of primary dysmenorrhea (PD) in China. However, the mechanisms that underlie this effect are unclear. We investigated the protective mechanism of GGD in a rat model of PD using label-free quantitative proteomics. The model was established by the administration of estradiol benzoate and oxytocin. Thirty rats were divided into three groups (ten rats/group): a control group (normal rats), a model group (PD rats), and a treatment group (PD rats treated with GGD). The serum levels of prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) were measured by ELISA. Nanohigh-performance liquid chromatography-tandem mass spectrometry (nano-HPLC-MS/MS) was used to identify differentially expressed proteins (DEPs), and bioinformatics was used to investigate the protein function. Proteomic data were validated by western blot analysis. Oxytocin-induced writhing responses and abnormal serum levels of PGE2 and PGF2α were reversed following the administration of GGD. A total of 379 DEPs were identified; 276 were identified between the control group and the model group, 144 were identified between the model group and the treatment group, and 41 were identified as DEPs that were common to all groups. Bioinformatics revealed that the DEPs between the control group and the model group were mainly associated with cellular component biogenesis and binding processes. The DEPs between the model group and the treatment group were mainly involved in the protein binding and metabolic process. The expression levels of HSP90AB1 and the phosphorylation levels of ERK, JNK, and P-p38 in the uteri of rats in the three groups were consistent with the proteomic findings; MAP kinases (ERK, JNK, and p38) are known to be involved in the production of inflammatory cytokines and oxytocin signaling while HSP90AB1 is known to be associated with estrogen signaling. Collectively, these data indicate that GGD may exert its protective function on PD by regulating the inflammatory response and signaling pathways associated with oxytocin and estrogen.

Dissecting the novel mechanism of reduning injection in treating Coronavirus Disease 2019 (COVID-19) based on network pharmacology and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

Reduning injection (RDNI) is a patented Traditional Chinese medicine that contains three Chinese herbal medicines, respectively are the dry aboveground part of Artemisia annua L., the flower of Lonicera japonica Thunb., and the fruit Gardenia jasminoides J.Ellis. RDNI has been recommended for treating Coronavirus Disease 2019 (COVID-19) in the "New Coronavirus Pneumonia Diagnosis and Treatment Plan".

AIM OF THE STUDY

To elucidate and verify the underlying mechanisms of RDNI for the treatment of COVID-19.

METHODS

This study firstly performed anti-SARS-CoV-2 experiments in Vero E6 cells. Then, network pharmacology combined with molecular docking was adopted to explore the potential mechanisms of RDNI in the treatment for COVID-19. After that, western blot and a cytokine chip were used to validate the predictive results.

RESULTS

We concluded that half toxic concentration of drug CC50 (dilution ratio) = 1:1280, CC50 = 2.031 mg crude drugs/mL (0.047 mg solid content/mL) and half effective concentration of drug (EC50) (diluted multiples) = 1:25140.3, EC50 = 103.420 μg crude drugs/mL (2.405 μg solid content/mL). We found that RDNI can mainly regulate targets like carbonic anhydrases (CAs), matrix metallopeptidases (MMPs) and pathways like PI3K/AKT, MAPK, Forkhead box O s and T cell receptor signaling pathways to reduce lung damage. We verified that RDNI could effectively inhibit the overexpression of MAPKs, PKC and p65 nuclear factor-κB. The injection could also affect cytokine levels, reduce inflammation and display antipyretic activity.

CONCLUSION

RDNI can regulate ACE2, Mpro and PLP in COVID-19. The underlying mechanisms of RDNI in the treatment for COVID-19 may be related to the modulation of the cytokine levels and inflammation and its antipyretic activity by regulating the expression of MAPKs, PKC and p65 nuclear factor NF-κB.

Safinamide prevents lipopolysaccharide (LPS)-induced inflammation in macrophages by suppressing TLR4/NF-κB signaling

Inflammation is a basal host defense response that eliminates the causes and consequences of infection and tissue injury. Macrophages are the primary immune cells involved in the inflammatory response. When activated by LPS, macrophages release various pro-inflammatory cytokines, chemokines, inflammatory mediators, and MMPs. However, unbridled inflammation causes further damage to tissues. Safinamide is a selective and reversible monoamine oxidase B (MAOB) inhibitor that has been used for the treatment of Parkinson's disease. In this study, we aimed to investigate whether safinamide has effects on LPS-treated macrophages. Our results show that safinamide inhibited the expression of pro-inflammatory cytokines such as IL-1α, TNF-α, and IL-6. Furthermore, safinamide suppressed the production of CXCL1 and CCL2, thereby preventing leukocyte migration. In addition, safinamide reduced iNOS-derived NO, COX-2-derived PGE₂, MMP-2, and MMP-9. Importantly, the functions of safinamide mentioned above were found to be dependent on its inhibitory effect on the TLR4/NF-κB signaling pathway. Our data indicates that safinamide may exert a protective effect against inflammatory response.

Elucidation of the Molecular Pathways Involved in the Protective Effects of AUY-922 in LPS-Induced Inflammation in Mouse Lungs

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) cause thousands of deaths every year and are associated with high mortality rates (~40%) due to the lack of efficient therapies. Understanding the molecular mechanisms associated with those diseases will most probably lead to novel therapeutics. In the present study, we investigated the effects of the Hsp90 inhibitor AUY-922 in the major inflammatory pathways of mouse lungs. Mice were treated with LPS (1.6 mg/kg) via intratracheal instillation for 24 h and were then post-treated intraperitoneally with AUY-922 (10 mg/kg). The animals were examined 48 h after AUY-922 injection. LPS activated the TLR4-mediated signaling pathways, which in turn induced the release of different inflammatory cytokines and chemokines. AUY-922 suppressed the LPS-induced inflammation by inhibiting major pro-inflammatory pathways (e.g., JAK2/STAT3, MAPKs), and downregulated the IL-1β, IL-6, MCP-1 and TNFα. The expression levels of the redox regulator APE1/Ref1, as well as the DNA-damage inducible kinases ATM and ATR, were also increased after LPS treatment. Those effects were counteracted by AUY-922. Interestingly, this Hsp90 inhibitor abolished the LPS-induced pIRE1α suppression, a major component of the unfolded protein response. Our study elucidates the molecular pathways involved in the progression of murine inflammation and supports our efforts on the development of new therapeutics against lung inflammatory diseases and sepsis.

NIX protein enhances antioxidant capacity of and reduces the apoptosis induced by HSP90 inhibitor luminespib/NVP-AUY922 in PC12 cells

Pheochromocytomas and paragangliomas (PCPGs) are catecholamine-producing neuroendocrine tumors. Accumulating evidences indicate that the blockade of antioxidative pathways might be a novel therapeutic approach to the treatment of PCPG. NIX has been confirmed to play a key role in maintaining redox homeostasis in tumors, while the function of NIX in PCPG remains unclear. In this study, the analyses of the disease-free survival (DFS) showed that high NIX protein level is related to poor prognosis in patients of PCPG. Consistent with this, high level of NIX protein upregulates the level of p-NF-κB and promotes the migration of PC12 cells. In NIX-over-expressing PC12 cells, the level of reactive oxygen species (ROS) is decreased while trolox-equivalent antioxidant capacity (TEAC) increased. But in NIX-silencing cells, ROS level is increased, while TEAC reversely reduced, consequently antioxidase and phase II enzymes of NRF2 signaling were activated, and elevated endoplasmic reticulum (ER) stress was observed. Additionally, the apoptosis induced by luminespib/NVP-AUY922, an inhibitor of heat shock protein 90 (HSP90, a cellular stress response factor), was enhanced in NIX-silencing cells but reduced in the NIX-over-expressing cells. All of these results indicated that high NIX protein level enhances antioxidant capacity of PC12 cells and reduces the apoptosis caused by cell stress, such as induced by luminespib/NVP-AUY922. Therefore, luminespib/NVP-AUY922 might be effective only for PCPG with low NIX level, while targeting NIX could be a further supplement to the therapeutic treatment strategy for PCPG patients with high NIX protein level.

Boldenone Undecylenate-Mediated Hepatorenal Impairment by Oxidative Damage and Dysregulation of Heat Shock Protein 90 and Androgen Receptors Expressions: Vitamin C Preventive Role

Boldenone Undecylenate (BLD) is a synthetic derivative of testosterone and a widely used anabolic androgenic steroid. The health risk of BLD use as a pharmaceutical or dietary supplement is still underestimated and under-reported. Vitamin C (VC) has been recognized as an antioxidant with prominent hepatorenal protective effects. This study investigated the possible preventive activity of VC against BLD-induced hepatorenal damage. Forty adult male Wistar rats were classified into five groups: control, vehicle control, VC (orally given 120 mg/kg b. wt./day), BLD (intramuscularly injected 5 mg/kg b. wt./week), and BLD + VC-treated groups. The experiment continued for eight weeks. Serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured. Serum contents of total protein (TP), albumin (ALB), globulin, total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and very-low-density lipoprotein-cholesterol (VLDL-C) were also assayed. Urea, creatinine, and uric acid levels were determined together with sodium and potassium electrolytes measuring. Moreover, oxidative stress indicators including reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GSR) as well as malondialdehyde (MDA) levels were measured in both hepatic and renal tissues. Corresponding histological examination of renal and hepatic tissues was conducted. Besides, immunohistochemical evaluations for androgen receptors protein (AR) and heat shock protein 90 (Hsp 90) expressions were performed. BLD caused significant rises in serum ALT, AST, TP, ALB, TC, TG, LDL-C, VLDL-C, urea, creatinine, uric acid, potassium, and MDA levels. Further, BLD-injected rats showed significant declines in the serum levels of HDL-C, sodium, GSH, GPx, GST, and GSR. Besides, distinct histopathological perturbations were detected in renal and hepatic tissues of BLD-injected rats. AR and Hsp 90 immunoexpression were increased in hepatic and renal tissues. In contrast, VC significantly reversed the BLD-induced hepatorenal damage in co-treated rats but not ameliorated AR protein overexpression. VC could be an efficient preventive supplement for mitigating BLD-induced hepatorenal damage, possibly via controlling oxidative stress events.

Restoring the endothelial barrier function in the elderly

Endothelial barrier dysfunction in the elderly has been associated with severe disorders, including acute respiratory distress syndrome, sepsis and COVID-19. Herein we deliver an opinion regarding the development of alternative therapeutic avenues to counteract the pathogenesis of the corresponding diseases.

Heat shock protein 90 inhibitors suppress pyroptosis in THP-1 cells

Pyroptosis is a recently discovered inflammatory form of programmed cell death which is mostly triggered by infection with intracellular pathogens and critically contributes to inflammation. Mitigating pyroptosis may be a potential therapeutic target in inflammatory diseases. However, small chemicals to reduce pyroptosis is still elusive. In the present study, we screened 155 chemicals from a microbial natural product library and found Geldanamycin, an HSP90 inhibitor, profoundly rescued THP-1 cells from pyroptosis induced by LPS plus Nigericin treatment. Consistently, other HSP90 inhibitors, including Radicicol, 17-DMAG and 17-AAG, all ameliorated pyroptosis in THP-1 cells by suppressing the inflammasome/Caspase-1/GSDMD signal pathway in pyroptosis. HSP90 inhibition compromised the protein stability of NLRP3, a critical component of the inflammasome. Moreover, up-regulated HSP70 may also contribute to this effect. HSP90 inhibition may thus be a potential therapeutic strategy in the treatment of inflammatory diseases in which pyroptosis plays a role.

Therapeutic Implications of Targeting Heat Shock Protein 70 by Immunization or Antibodies in Experimental Skin Inflammation

Heat shock proteins (Hsp) are constitutive and stress-induced molecules which have been reported to impact innate and adaptive immune responses. Here, we evaluated the role of Hsp70 as a treatment target in the imiquimod-induced, psoriasis-like skin inflammation mouse model and related in vitro assays. We found that immunization of mice with Hsp70 resulted in decreased clinical and histological disease severity associated with expansion of T cells in favor of regulatory subtypes (CD4⁺FoxP3⁺/CD4⁺CD25⁺ cells). Similarly, anti-Hsp70 antibody treatment led to lowered disease activity associated with down-regulation of pro-inflammatory Th17 cells. A direct stimulating action of Hsp70 on regulatory T cells and its anti-proliferative effects on keratinocytes were confirmed in cell culture experiments. Our observations suggest that Hsp70 may be a promising therapeutic target in psoriasis and potentially other autoimmune dermatoses.

Inhibition of heat shock protein 90 alleviates cholestatic liver injury by decreasing IL-1β and IL-18 expression

Severe cholestatic liver injury diseases, such as obstructive jaundice and the subsequent acute obstructive cholangitis, are induced by biliary tract occlusion. Heat shock protein 90 (HSP90) inhibitors have been demonstrated to be protective for various organs. The potential of HSP90 inhibitors in the treatment of cholestatic liver injury, however, remains unclear. In the present study, rat models of bile duct ligation (BDL) were established, the HSP90 inhibitor 17-dimethylamino-ethylamino-17-demethoxygeldanamycin (17-DMAG) was administered, and its ability to ameliorate the cholestasis-induced liver injuries was evaluated. In the BDL rat models and clinical samples, increased HSP90 expression was observed to be associated with cholestatic liver injury. Furthermore, 17-DMAG alleviated cholestasis-induced liver injury in the rat models, as revealed by the assessment of pathological changes and liver function. In addition, 17-DMAG protected hepatocytes against cholestatic injury in vitro. Further assays indicated that 17-DMAG administration prevented cholestasis-induced liver injury in the rats by decreasing the expression of interleukin (IL)-1β and IL-18. Moreover, 17-DMAG also decreased the cholestasis-induced upregulation of IL-1β and IL-18 in liver sinusoidal endothelial cells in vitro. In conclusion, the HSP90 inhibitor 17-DMAG is able to prevent liver injury in rats with biliary obstruction, and this phenomenon is associated with the reduction of IL-1β and IL-18 expression.

Exosomes: Emerging Diagnostic and Therapeutic Targets in Cutaneous Diseases

Skin is the largest human organ and is continuously exposed to various exogenous and endogenous trigger factors affecting body homeostasis. A number of mechanisms, including genetic, inflammatory and autoimmune ones, have been implicated in the pathogenesis of cutaneous diseases. Recently, there has been considerable interest in the role that extracellular vesicles, particularly exosomes, play in human diseases, through their modulation of multiple signaling pathways. Exosomes are nano-sized vesicles secreted by all cell types. They function as cargo carriers shuttling proteins, nucleic acids, lipids etc., thus impacting the cell-cell communications and transfer of vital information/moieties critical for skin homeostasis and disease pathogenesis. This review summarizes the available knowledge on how exosomes affect pathogenesis of cutaneous diseases, and highlights their potential as future targets for the therapy of various skin diseases.

Autologous extracellular Hsp70 exerts a dual role in rheumatoid arthritis

Extracellular heat shock proteins (Hsp) influence the adaptive immune response and may ameliorate pathogenesis of autoimmune diseases. While some preclinical observations suggest that highly conserved bacterial and/or murine Hsp70 peptides have potential utility in treatment of rheumatoid arthritis (RA) via induction of T regulatory cells (Treg), the role of extracellular inducible human Hsp70 in adaptive immune processes requires further investigation. The present study evaluated Hsp70 influence on inflammatory cytokine-mediated modulation of T cell immunophenotype in ways that influence RA onset and severity. Initial experiments in the present investigation revealed that serum levels of Hsp70 are approximately 2-fold higher in RA patients versus healthy control subjects. To explore the effect of extracellular Hsp70 on key processes underlying the adaptive immune system, the effects of a highly pure, substrate-, and endotoxin-free human Hsp70 on polarization of the T helper cell subpopulations, including CD4+IL-17+ (Th17), CD4+FoxP3+ (Treg), CD4+IFN-γ+ (Th1), and CD4+IL-4+ (Th2), were studied in naïve human peripheral blood mononuclear cell (PBMC) cultures stimulated with anti-CD3/28 mAb. Major findings included an observation that while Hsp70 treatment increased Th17 frequencies and Th17/Treg ratio, the frequency of Th1 cells and the Th1/Th2 ratio were significantly decreased in the Hsp70-treated PBMC cultures. Moreover, data shown here provides preliminary suggestion that major contributing Hsp70-mediated immunomodulation includes interleukin 6 (IL-6) influence on Th17/Treg and Th1/Th2, since expression of this inflammatory cytokine is enhanced by in vitro Hsp70 treatment. These results are nevertheless preliminary and require further investigation to validate the above model.

Heat Shock Protein 70 as a Double Agent Acting Inside and Outside the Cell: Insights into Autoimmunity

Heat shock proteins (Hsp) are a diverse group of constitutive and/or stress-induced molecules that are categorized into several classes on the basis of their molecular weight. Mammalian Hsp have been mostly regarded as intracellular chaperones that mediate a range of essential cellular functions, including proper folding of newly synthesized polypeptides, refolding of denatured proteins, protein transport, and stabilization of native proteins' structures. The well-characterized and highly evolutionarily conserved, stress-inducible 70-kDa heat shock protein (Hsp70), is a key molecular chaperone that is overexpressed in the cell in response to stress of various origin. Hsp70 exhibits an immunosuppressive activity via, e.g., downregulation of the nuclear factor-kappa B (NF-κB) activation, and pharmacological induction of Hsp70 can ameliorate the autoimmune arthritis development in animal models. Moreover, Hsp70 might be passively or actively released from the necrotic or stressed cells, respectively. Highly immunogenic extracellular Hsp70 has been reported to impact both the innate and adaptive immune responses, and to be implicated in the autoimmune reaction. In addition, preclinical studies revealed that immunization with highly conserved Hsp70 peptides could be regarded as a potential treatment target for autoimmune arthritis, such as the rheumatoid arthritis, via induction of antigen-specific regulatory T helper cells (also called Treg). Here, a dual role of the intra- and extracellular Hsp70 is presented in the context of the autoimmune reaction.