Heat shock protein 90: a pathophysiological factor and novel treatment target in autoimmune bullous skin diseases

Heat shock protein-related diagnostic signature and molecular subtypes in ankylosing spondylitis: new pathogenesis insights

Heat shock proteins (HSP) have been associated with a range of persistent inflammatory disorders; however, little research has been conducted on the involvement of HSP in the development of ankylosing spondylitis (AS). The research aims to identify a diagnostic signature based on HSP-related genes and determine the molecular subtypes of AS. We gathered the transcriptional data of patients with AS from the GSE73754 dataset and conducted a literature search for HSP-related genes (HRGs). The logistic regression model was utilized for the identification of hub HRGs associated with AS. Subsequently, these HRGs were employed in the construction of a nomogram prediction model. We employed a consensus clustering approach to identify novel molecular subgroups. Subsequently, we conducted functional analyses, encompassing GO, KEGG, and GSEA, to elucidate the underlying mechanisms between these subgroups. To assess the immunological landscape, we employed the xCell algorithm. Through logistic regression analysis, the four core HRGs (CCT2, HSPA6, DNAJB14, and DNAJC5) were confirmed as potential biomarkers for AS. Subsequent stratification revealed two distinct molecular phenotypes, designated as Cluster 1 and Cluster 2. Notably, Cluster 2 was characterized by the upregulation of pathways pertinent to immune response and inflammation. Our research suggests that the CCT2, HSPA6, DNAJB14, and DNAJC5 exhibit potential as effective blood-based diagnostic biomarkers for AS. These findings contribute to a deeper comprehension of the underlying mechanisms involved in the development of AS and offer potential targets for personalized therapeutic interventions.

HSP90 Exacerbates Bone Destruction in Rheumatoid Arthritis by Activating TRAF6/NFATc1 Signaling

Rheumatoid arthritis (RA) is an autoimmune disease characterized by a notably high disability rate, primarily attributed to cartilage and bone degradation. The involvement of heat shock protein 90 (HSP90) as a molecular chaperone in the inflammatory response of RA has been established, but its role in bone destruction remains uncertain. In the present study, the expression of HSP90 was augmented in osteoclasts induced by the receptor activator of nuclear factor-κB ligand. Additionaly, it was observed that the outcomes revealed a noteworthy inhibition of osteoclast formation and differentation when triptolide was utilized to hinder the expression of HSP90. Furthermore, the positive influence of HSP90 in osteoclast differentiation was substantiated by overexpressing HSP90 in osteoclast precursor cells. Mechanically, HSP90 significantly activated the TNF receptor-associated factor 6 (TRAF6)/Nuclear factor of activated T cells 1 (NFATc1) signaling axis, accompanied by markedly promoting osteoclast differentiation. This effect was consistently observed in the destructive joint of rats with collagen-induced arthritis, where HSP90 effectively activated osteoclasts and contributed to arthritic bone destruction by activating the TRAF6/NFATc1 signaling. Overall, the findings of this study provide compelling evidence that HSP90 exacerbates bone destruction in RA by promoting osteoclast differentiation through the activation of TRAF6/NFATc1 signaling, and interference with HSP90 may be a promising strategy for the discovery of anti-arthritic bone destruction agents.

Advancing Treatment in Bullous Pemphigoid: A Comprehensive Review of Novel Therapeutic Targets and Approaches

Bullous pemphigoid is one of the most common autoimmune bullous diseases occurring primarily in the elderly. Pathogenic autoantibodies against BP180 and BP230 at the dermal-epidermal junction cause subepidermal blisters, erosions, and intense pruritus, all of which adversely affect the patients' quality of life and may increase their morbidity and mortality. Current systemic treatment options for bullous pemphigoid are limited to corticosteroids and immunosuppressants, which can have substantial side effects on these vulnerable patients that even exceed their therapeutic benefits. Therefore, more precisely, targeting therapies to the pathogenic cells and molecules in bullous pemphigoid is an urgent issue. In this review, we describe the pathophysiology of bullous pemphigoid, focusing on autoantibodies, complements, eosinophils, neutrophils, proteases, and the T helper 2 and 17 axes since they are crucial in promoting proinflammatory environments. We also highlight the emerging therapeutic targets for bullous pemphigoid and their latest discoveries in clinical trials or experimental studies. Further well-designed studies are required to establish the efficacy and safety of these prospective therapeutic options.

Matrine regulates Th1/Th2 inflammatory responses by inhibiting the Hsp90/NF-κB signaling axis to alleviate atopic dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disease. Matrine is the main component of the traditional Chinese medicine Sophora flavescens, and it poses good therapeutic effects on inflammatory diseases. This study aimed to explore the pharmacological effects of matrine on AD and its underlying mechanism. An AD mouse model and inflamed human epidermal keratinocyte cells (HaCaT) cells were established. Histopathological aspects were examined using hematoxylin and eosin staining, toluidine blue staining, and immunohistochemistry. The mRNA and protein expressions were assessed using quantitative real-time polymerase chain reaction and Western blot, respectively. The secretions of cytokines and chemokines were examined by enzyme-linked immunosorbent assay. Flow cytometry was carried out to analyze the proportions of T-helper (Th) 1 and Th2 cells. Herein, our results displayed that matrine diminished AD symptoms and decreased heat shock protein 90 (Hsp90) expression. Matrine decreased the Th2 cytokine levels in the ear tissues and serum, and it also significantly repressed inflammatory cytokines (thymus activation regulated chemokine and interleukin-6) secretions by repressing the Hsp90/NF-κB signaling axis in inflamed HaCaT cells. Furthermore, matrine inhibited Th2 differentiation of CD4⁺ T cells when co-cultured with inflamed HaCaT cells. Matrine can regulate the Th1/Th2 inflammatory response by inhibiting the Hsp90/NF-κB signaling axis to alleviate AD. Therefore, it may be a candidate for AD treatment.

Epidermolysis Bullosa Acquisita-Current and Emerging Treatments

Epidermolysis bullosa acquisita (EBA) is a rare chronic autoimmune subepidermal blistering disease of the skin and mucous membranes, usually beginning in adulthood. EBA is induced by autoantibodies to type VII collagen, a major component of anchoring fibrils in the dermal-epidermal junction (DEJ). The binding of autoantibodies to type-VII collagen subsequently leads to the detachment of the epidermis and the formation of mucocutaneous blisters. EBA has two major clinical subtypes: the mechanobullous and inflammatory variants. The classic mechanobullous variant presentation consists of skin fragility, bullae with minimal clinical or histological inflammation, erosions in acral distribution that heal with scarring, and milia formation. The inflammatory variant is challenging to differentiate from other autoimmune bullous diseases, most commonly bullous pemphigoid (BP) but also mucous membrane pemphigoid (MMP), Brunsting-Perry pemphigoid, and linear IgA dermatosis. Due to its recalcitrance conventional treatment of epidermolysis bullosa acquisita is shown to be demanding. Here we discuss novel therapeutic strategies that have emerged and which could potentially improve the quality of life in patients with EBA.

Targeting heat shock proteins 90 and 70: A promising remedy for both autoimmune bullous diseases and COVID-19

Heat shock proteins (Hsps), including Hsp90 and Hsp70, are intra- and extracellular molecules implicated in cellular homeostasis and immune processes and are induced by cell stress such as inflammation and infection. Autoimmune bullous disorders (AIBDs) and COVID-19 represent potentially life-threatening inflammatory and infectious diseases, respectively. A significant portion of AIBDs remain refractory to currently available immunosuppressive therapies, which may represent a risk factor for COVID-19, and suffer from treatment side-effects. Despite advances in vaccination, there is still a need to develop new therapeutic approaches targeting SARS-CoV-2, especially considering vaccine hesitancy, logistical distribution challenges, and breakthrough infections. In this mini review, we briefly summarize the role of targeting Hsp90/70 as a promising double-edged sword in the therapy of AIBDs and COVID-19.

Translational proteomics and phosphoproteomics: Tissue to extracellular vesicles

We are currently experiencing a rapidly developing era in terms of translational and clinical medical sciences. The relatively mature state of nucleic acid examination has significantly improved our understanding of disease mechanism and therapeutic potential of personalized treatment, but misses a large portion of phenotypic disease information. Proteins, in particular phosphorylation events that regulates many cellular functions, could provide real-time information for disease onset, progression and treatment efficacy. The technical advances in liquid chromatography and mass spectrometry have realized large-scale and unbiased proteome and phosphoproteome analyses with disease relevant samples such as tissues. However, tissue biopsy still has multiple shortcomings, such as invasiveness of sample collection, potential health risk for patients, difficulty in protein preservation and extreme heterogeneity. Recently, extracellular vesicles (EVs) have offered a great promise as a unique source of protein biomarkers for non-invasive liquid biopsy. Membranous EVs provide stable preservation of internal proteins and especially labile phosphoproteins, which is essential for effective routine biomarker detection. To aid efficient EV proteomic and phosphoproteomic analyses, recent developments showcase clinically-friendly EV techniques, facilitating diagnostic and therapeutic applications. Ultimately, we envision that with streamlined sample preparation from tissues and EVs proteomics and phosphoproteomics analysis will become routine in clinical settings.

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.

Subunit-Specific Reactivity of Autoantibodies Against Laminin-332 Reveals Direct Inflammatory Mechanisms on Keratinocytes

Laminin-332 pemphigoid is a rare and severe autoimmune blistering disease, caused by IgG autoantibodies targeting laminin-332 in the dermal-epidermal basement zone. Laminin-332 pemphigoid is characterized by variable inflammatory infiltrate and the predominance of non-complement-fixing antibodies. Given these findings, we hypothesized that IgG autoantibodies to laminin-332 directly resulted in keratinocyte expression of inflammatory factors. We performed RNA-seq on primary human keratinocytes treated with IgG from patients with laminin-332 pemphigoid. Genes for numerous cytokines and chemokines were upregulated, including CSF2, CSF3, CXCL1, CXCL5, CXCL3, CXCL8, CXCL10, CXCL1, IL6, IL7, IL15, IL23, IL32, IL37, TGFB2 as well as metalloproteases. Considering the pro-inflammatory and proteolytic effect of autoantibodies from patients with laminin-332 pemphigoid identified in our initial experiment, we next questioned whether the reactivity against specific laminin subunits dictates the inflammatory and proteolytic keratinocyte response. Then, we treated keratinocytes with IgG from a separate cohort of patients with reactivity against individual subunits of laminin-332. We identified upregulation of IL-1α, IL-6, IL-8, CXCL1, MMP9, TSLP, and GM-CSF at the protein level, most notably in keratinocytes treated with IgG from laminin β3-reactive patients. We for the first time demonstrated a pro-inflammatory response, similar to that described in keratinocytes treated with IgG autoantibodies from patients with bullous pemphigoid, providing novel insight into the pathogenesis of laminin-332 pemphigoid and laminin-332 biology.

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.

The Pathophysiological Role of Heat Shock Response in Autoimmunity: A Literature Review

Within the last two decades, there has been increasing evidence that heat-shock proteins can have a differential influence on the immune system. They can either provoke or ameliorate immune responses. This review focuses on outlining the stimulatory as well as the inhibitory effects of heat-shock proteins 27, 40, 70, 65, 60, and 90 in experimental and clinical autoimmune settings.

Characterizing the proteome of bullous pemphigoid blister fluid utilizing tandem mass tag labeling coupled with LC-MS/MS

Bullous pemphigoid is an autoimmune blistering disease caused by autoantibodies against components of the cutaneous basement membrane zone. Autoantibodies lead to complement-dependent and -independent inflammation and blistering. Blister fluid is a valuable biologic resource, as it provides insight into both systemic and local microenvironment responses. Here, we utilized liquid chromatography with tandem mass spectrometry to characterize the bullous pemphigoid blister fluid proteome. We then depleted exosomes to better understand the exosomal versus non-exosomal proteome. We identified 339 proteins in the blister fluid of bullous pemphigoid patients. Gene ontology demonstrated enrichment of several key biologic processes including innate immune response, neutrophil degranulation, platelet degranulation, and complement activation. Exosome depletion resulted in a significant decrease in normalized reporter intensities of 192 proteins, consistent with our observation of a large number of exosomal proteins found in the blister fluid. We then compared the bullous pemphigoid blister fluid proteome to prior proteomic datasets in suction blister fluid, snake bites, and thermal burns, identifying 76 proteins unique to bullous pemphigoid. These include major basic protein, eosinophil peroxidase, galectin-10, and the immunoglobulin epsilon heavy constant region, consistent with tissue eosinophilia. We lastly validated several previously reported blister fluid exosomal components. Blister fluid in bullous pemphigoid contains a mixture of numerous biologic processes. While many of these processes are shared with blistering from alternative causes, we have identified several notable features unique to bullous pemphigoid.

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.

Covid-19, heat shock proteins, and autoimmune bullous diseases: a potential link deserving further attention

A link between Covid-19 and development of autoimmunity has been reported. A possible explanation could be molecular mimicry between SARS-CoV-2 and human proteins. Peptide sharing has been found between antigenic epitopes of this virus and heat shock proteins (Hsp) 60 and 90, both of which are associated with autoimmune diseases including those of the bullous type. In particular, there is evidence for the latter Hsp acting as a pathophysiological factor and treatment target in autoimmune blistering dermatoses. Considering multimodal anti-inflammatory mechanisms of action of anti-Hsp90 treatment and drug repositioning results, it may be hypothesized that Hsp90 inhibition could also be a treatment option for cytokine storm-mediated acute respiratory distress syndrome in Covid-19 patients. Hence, although Covid-19-induced autoimmune bullous diseases have not been described in the literature so far, the potential relationship between Covid-19, Hsp, and these autoimmune disorders deserves further attention with respect to both pathophysiology and treatment.

In silico evaluation of drugs used in treatment of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a chronic T cell-mediated, immunological, mucocutaneous disease with a number of genes and inflammatory mediators implicated in its pathogenesis. Heart shock protein 70 and the proinflammatory mediator TNFα have been predominantly involved in the etiopathogenesis of oral lichen planus.

METHODS

In this study, the action of 27 commonly used drugs for treating OLP at HSP70 and TNFα were evaluated by molecular docking using Maestro Schrodinger version 10.1. X-ray crystallographic structures of the target proteins, that is, Heat Shock Protein 70 (PDB Code: 6FDT) and tumor necrosis factor alpha-1 (PDB Code: 1TNF) were obtained from Protein Data Bank (PDB). The structures of the ligands (27 drugs) were obtained from PubChem in.sdf format. Using Ligprep, pre-processing of the ligands was done. Extra-precision docking was performed with the prepared protein and the ligands.

RESULTS

With respect to HSP70, the highest dock score (-4.768) and glide score (-4.818) were seen with hydroxychloroquine (HCQ), followed by epigallocatechin gallate (green tea), methotrexate, and curcumin. The highest dock (-9.525) and glide score (-9.584) in TNFα were seen in with epigallocatechin gallate, followed by HCQ, dapsone, and methotrexate.

CONCLUSION

The results of the study tend to explain the clinical use of HCQ in recalcitrant and severe cases, as well as the anti-inflammatory property of epigallocatechin gallate. The results of the study open ventures for exploring the in silico behavior of drugs for effective pathological management.

Factors associated with the activity and severity of bullous pemphigoid: a review

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease. It usually affects people older than 70 years of age. The two main autoantigens are BP180 and BP230, both of which are components of hemidesmosomes. Immunoglobulin (Ig)G and IgE autoantibodies to BP180 detected by the enzyme-linked immunoassay (ELISA) show close associations with the activity and severity of BP. In addition, inflammatory cells (eosinophils, neutrophils and mast cells) and cytokines (e.g. interleukins and CC chemokine ligands) play an important part in the pathogenesis, activity and severity of BP. We summarized the potential contribution of each factor postulated to be associated with the activity and severity of BP, and provide guidance for clinicians to pay timely and close attention to such parameters. This review may also promote the development of novel therapies for BP.Key MessagesBullous Pemphigoid Disease Area Index (BPDAI) is a scoring system which can reflect the extent of clinical involvement of BP patients.The titres of IgE autoantibodies and IgG autoantibodies against the NC16A domain of BP180 are closely correlated with the activity and severity of BP.Many inflammatory cells and molecules, such as eosinophils and interleukins, can also reflect the activity and severity of BP.

Heat shock proteins in the physiology and pathophysiology of epidermal keratinocytes

Heat shock proteins (HSPs), a large group of highly evolutionary conserved proteins, are considered to be main elements of the cellular proteoprotection system. HSPs are encoded by genes activated during the exposure of cells to proteotoxic factors, as well as by genes that are expressed constitutively under physiological conditions. HSPs, having properties of molecular chaperones, are involved in controlling/modulation of multiple cellular and physiological processes. In the presented review, we summarize the current knowledge on HSPs in the biology of epidermis, the outer skin layer composed of stratified squamous epithelium. This tissue has a vital barrier function preventing from dehydratation due to passive diffusion of water out of the skin, and protecting from infection and other environmental insults. We focused on HSPB1 (HSP27), HSPA1 (HSP70), HSPA2, and HSPC (HSP90), because only these HSPs have been studied in the context of physiology and pathophysiology of the epidermis. The analysis of literature data shows that HSPB1 plays a role in the regulation of final steps of keratinization; HSPA1 is involved in the cytoprotection, HSPA2 contributes to the early steps of keratinocyte differentiation, while HSPC is essential in the re-epithelialization process. Since HSPs have diverse functions in various types of somatic tissues, in spite of multiple investigations, open questions still remain about detailed roles of a particular HSP isoform in the biology of epidermal keratinocytes.

Roles of Extracellular HSPs as Biomarkers in Immune Surveillance and Immune Evasion

Extracellular heat shock proteins (ex-HSPs) have been found in exosomes, oncosomes, membrane surfaces, as well as free HSP in cancer and various pathological conditions, also known as alarmins. Such ex-HSPs include HSP90 (α, β, Gp96, Trap1), HSP70, and large and small HSPs. Production of HSPs is coordinately induced by heat shock factor 1 (HSF1) and hypoxia-inducible factor 1 (HIF-1), while matrix metalloproteinase 3 (MMP-3) and heterochromatin protein 1 are novel inducers of HSPs. Oncosomes released by tumor cells are a major aspect of the resistance-associated secretory phenotype (RASP) by which immune evasion can be established. The concepts of RASP are: (i) releases of ex-HSP and HSP-rich oncosomes are essential in RASP, by which molecular co-transfer of HSPs with oncogenic factors to recipient cells can promote cancer progression and resistance against stresses such as hypoxia, radiation, drugs, and immune systems; (ii) RASP of tumor cells can eject anticancer drugs, targeted therapeutics, and immune checkpoint inhibitors with oncosomes; (iii) cytotoxic lipids can be also released from tumor cells as RASP. ex-HSP and membrane-surface HSP (mHSP) play immunostimulatory roles recognized by CD91+ scavenger receptor expressed by endothelial cells-1 (SREC-1)+ Toll-like receptors (TLRs)+ antigen-presenting cells, leading to antigen cross-presentation and T cell cross-priming, as well as by CD94+ natural killer cells, leading to tumor cytolysis. On the other hand, ex-HSP/CD91 signaling in cancer cells promotes cancer progression. HSPs in body fluids are potential biomarkers detectable by liquid biopsies in cancers and tissue-damaged diseases. HSP-based vaccines, inhibitors, and RNAi therapeutics are also reviewed.

Transcriptomic analysis of circulating neutrophils in metabolically stressed peripartal grazing dairy cows

The high metabolic demand during the transition into lactation places cows at greater risk of metabolic and infectious disease than at any other time in their lactation cycle. Additionally, a change occurs in the innate immune response during this period, which contributes to increased risk of disease. In the current study, we compared the transcriptomes of neutrophils from dairy cows divergent in their metabolic health post-calving. Cows (n = 5 per risk group) were selected from a parent experiment (n = 45 cows). Those with high or low concentrations of plasma nonesterified fatty acids, plasma β-hydroxybutyrate, and liver triacylglycerol in both wk 1 and 2 were deemed to be at "high risk" (HR) or "low risk" (LR) of metabolic dysfunction, respectively. Circulating neutrophils were isolated at 3 time points during the transition period (d 0 and wk 1 and 4 post-calving), and gene expression was analyzed using RNA sequencing. Differential gene expression between the risk groups was determined using edgeR (http://bioconductor.org), and pathway analysis was conducted using Ingenuity Pathway Analysis (Ingenuity Systems, Qiagen, Valencia, CA). Statistical analysis indicated no interaction between risk and week. Therefore, the overall effect of risk was analyzed across all time points. In total, 3,500 genes were differentially expressed between the HR and LR cows (false discovery rate < 0.05). Of these, 2,897 genes were identified by Ingenuity Pathway Analysis and used for pathway analysis. Of the relevant pathways identified, neutrophils isolated from HR cows showed downregulation of genes involved in the recruitment of granulocytes, interferon signaling, and apoptosis, and upregulation of genes involved in cell survival. The results indicate that metabolically stressed cows had reduced neutrophil function during the peripartum period, highlighting a potential relationship between subclinical metabolic disease and innate immune function that suggests that metabolic health negatively affects the innate immune system and may contribute to the state of immunosuppression during the peripartum period. In this way, the metabolic stress among the HR cows may reduce their ability to combat infection during the transition period.

Associations of HSP90AA2 gene polymorphisms with disease susceptibility, glucocorticoids efficacy and health-related quality of life in Chinese systemic lupus erythematosus patients

Although the current glucocorticoids (GCs) treatment for systemic lupus erythematosus (SLE) is effective to a certain extent, the difference in therapeutic effect between patients is still a widespread problem. Some patients can have repeated attacks that greatly diminish their quality of life. This study was conducted to investigate the relationship between HSP90AA2 polymorphisms and disease susceptibility, GCs efficacy and health-related quality of life (HRQoL) in Chinese SLE patients. A case-control study was performed in 470 SLE patients and 470 normal controls. Then, 444 patients in the case group were followed up for 12 weeks to observe efficacy of GCs and improvement of HRQoL. Two single nucleotide polymorphisms (SNPs) of HSP90AA2 were selected for genotyping: rs1826330 and rs6484340. HRQoL was assessed using the SF-36 questionnaire. The minor T allele of rs1826330 and the TT haplotype formed by rs1826330 and rs6484340 showed associations with decreased SLE risk (T allele: P_BH = 0.022; TT haplotype: P_BH = 0.033). A significant association between rs6484340 and improvement of HRQoL was revealed in the follow-up study. Five subscales of SF-36 were appeared to be influenced by rs6484340: total score of SF-36 (additive model: P_BH = 0.026), physical function (additive model: P_BH = 0.026), role-physical (recessive model: P_BH = 0.041), mental health (dominant model: P_BH = 0.047), and physical component summary (additive model: P_BH = 0.026). No statistical significance was found between HSP90AA2 gene polymorphisms and GCs efficacy. These results revealed a genetic association between HSP90AA2 and SLE. Remarkably, HSP90AA2 has an impact on the improvement of HRQoL in Chinese population with SLE.

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.

Association between bullous pemphigoid and malignancy: A meta-analysis

It has been suggested that bullous pemphigoid is associated with an increased risk of malignancy, but the evidence is inconsistent. Therefore, a meta-analysis was conducted to explore this association. PUBMED and Embase were searched for studies investigating the association between bullous pemphigoid and malignancy. This meta-analysis included 16 studies with a total of 9398 cases of bullous pemphigoid. The rate of malignancy in patients with bullous pemphigoid was 11% (95% CI: 9-14, P < 0.001); 9% (95% CI: 6-13, P < 0.003) for women and 13% (95% CI: 9-18, P < 0.03) for men, with a statistically insignificant higher risk in men (OR = 1.30, 95% CI: 0.99-1.71, P = 0.06). The event rate was 9% (95% CI: 5-14, P < 0.001) in the Asian population and 13% (95% CI: 10-17, P < 0.001) in the European population, with a statistically significant lower risk in the Asians population (OR = 0.69, 95% CI: 0.57-0.84; P < 0.001). The event rate of malignancy was higher in patients with bullous pemphigoid than in matched controls (OR = 2.08, 95% CI: 1.22-3.55; P = 0.005). The overall event rate of malignancy was higher in the bullous pemphigoid group than in matched controls. Caution is required when interpreting these results, as potential confounding variables were not controlled for.

Autoantibodies of non-inflammatory bullous pemphigoid hardly deplete type XVII collagen of keratinocytes

Type XVII collagen (COL17) and the non-collagenous 16A (NC16A) domain is regarded as the major pathogenic domains for bullous pemphigoid (BP). Some patients with BP have autoantibodies against parts of COL17 outside the NC16A domain (hereinafter the non-NC16A domain) and show less inflammatory manifestations. There were no significant differences in titres and IgG subclasses between NC16A-BP and non-NC16A-BP as determined by indirect immunofluorescent microscopy. The neutrophil activation capacities determined by ROS release did not differ between NC16A-BP and non-NC16A-BP. However, NC16A-BP IgG depleted COL17 in a dose-dependent manner. Treatment with NC16A-BP IgG, but not with non-NC16A-BP IgG, significantly decreased the adhesion strength. We speculate that the differences in clinical severity between NC16A-BP and non-NC16A-BP relate to the degree of COL17 depletion.

Paraneoplastic Pemphigus and Autoimmune Blistering Diseases Associated with Neoplasm: Characteristics, Diagnosis, Associated Neoplasms, Proposed Pathogenesis, Treatment

Autoimmune paraneoplastic and neoplasm-associated skin syndromes are characterized by autoimmune-mediated cutaneous lesions in the presence of a neoplasm. The identification of these syndromes provides information about the underlying tumor, systemic symptoms, and debilitating complications. The recognition of these syndromes is particularly helpful in cases of skin lesions presenting as the first sign of the malignancy, and the underlying malignancy can be treated in a timely manner. Autoimmune paraneoplastic and neoplasm-associated bullous skin syndromes are characterized by blister formation due to an autoimmune response to components of the epidermis or basement membrane in the context of a neoplasm. The clinical manifestations, histopathology and immunopathology findings, target antigens, associated neoplasm, current diagnostic criteria, current understanding of pathogenesis, and treatment options for a selection of four diseases are reviewed. Paraneoplastic pemphigus manifests with clinically distinct painful mucosal erosions and polymorphic cutaneous lesions, and is often associated with lymphoproliferative neoplasm. In contrast, bullous pemphigoid associated with neoplasm presents with large tense subepidermal bullae of the skin, and mild mucosal involvement, but without unique clinical features. Mucous membrane pemphigoid associated with neoplasm is a disorder of chronic subepithelial blisters that evolve into erosions and ulcerations that heal with scarring, and involves stratified squamous mucosal surfaces. Linear IgA dermatosis associated with neoplasm is characterized by annularly grouped pruritic papules, vesicles, and bullae along the extensor surfaces of elbows, knees, and buttocks. Physicians should be aware that these autoimmune paraneoplastic and neoplasm-associated syndromes can manifest distinct or similar clinical features as compared with the non-neoplastic counterparts.

Cytoskeletal Regulation of Inflammation and Its Impact on Skin Blistering Disease Epidermolysis Bullosa Acquisita

Actin remodelling proteins regulate cytoskeletal cell responses and are important in both innate and adaptive immunity. These responses play a major role in providing a fine balance in a cascade of biological events that results in either protective acute inflammation or chronic inflammation that leads to a host of diseases including autoimmune inflammation mediated epidermolysis bullosa acquisita (EBA). This review describes the role of the actin cytoskeleton and in particular the actin remodelling protein called Flightless I (Flii) in regulating cellular inflammatory responses and its subsequent effect on the autoimmune skin blistering disease EBA. It also outlines the potential of an antibody based therapy for decreasing Flii expression in vivo to ameliorate the symptoms associated with EBA.

The Role of Heat Shock Protein 90B1 in Patients with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogenetic disorder in women that is characterized by arrested follicular growth and anovulatory infertility. The altered protein expression levels in the ovarian tissues reflect the molecular defects in folliculogenesis. To identify aberrant protein expression in PCOS, we analyzed protein expression profiles in the ovarian tissues of patients with PCOS. We identified a total of 18 protein spots that were differentially expressed in PCOS compared with healthy ovarian samples. A total of 13 proteins were upregulated and 5 proteins were downregulated. The expression levels of heat shock protein 90B1 (HSP90B1) and calcium signaling activator calmodulin 1 (CALM1) were increased by at least two-fold. The expression levels of HSP90B1 and CALM1 were positively associated with ovarian cell survival and negatively associated with caspase-3 activation and apoptosis. Knock-down of HSP90B1 with siRNA attenuated ovarian cell survival and increased apoptosis. In contrast, ovarian cell survival was improved and cell apoptosis was decreased in cells over-expressing HSP90B1. These results demonstrated the pivotal role of HSP90B1 in the proliferation and survival of ovarian cells, suggesting a critical role for HSP90B1 in the pathogenesis of PCOS. We also observed a downregulation of anti-inflammatory activity-related annexin A6 (ANXA6) and tropomyosin 2 (TPM2) compared with the normal controls, which could affect cell division and folliculogenesis in PCOS. This is the first study to identify novel altered gene expression in the ovarian tissues of patients with PCOS. These findings may have significant implications for future diagnostic and treatment strategies for PCOS using molecular interventions.

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

Heat shock protein 90 (Hsp90), a 90-kDa molecular chaperone, is responsible for biological activities of key signaling molecules (clients) such as protein kinases, ubiquitin ligases, steroid receptors, cell cycle regulators, and transcription factors regulating various cellular processes, including growth, survival, differentiation, and apoptosis. Because Hsp90 is also involved in stabilization of oncogenic 'client' proteins, its specific chaperone activity blockers are currently being tested as anticancer agents in advanced clinical trials. Recent in vitro and in vivo studies have shown that Hsp90 is also involved in activation of innate and adaptive cells of the immune system. For these reasons, pharmacological inhibition of Hsp90 has been evaluated in murine models of autoimmune and inflammatory diseases. This mini-review summarizes current knowledge of the effects of Hsp90 inhibitors on autoimmune and inflammatory diseases' features and is based solely on preclinical studies.