Extracellular heat shock protein 90 binding to TGFβ receptor I participates in TGFβ-mediated collagen production in myocardial fibroblasts

A bioinformatics approach to elucidate conserved genes and pathways in C. elegans as an animal model for cardiovascular research

Cardiovascular disease (CVD) is a collective term for disorders of the heart and blood vessels. The molecular events and biochemical pathways associated with CVD are difficult to study in clinical settings on patients and in vitro conditions. Animal models play a pivotal and indispensable role in CVD research. Caenorhabditis elegans, a nematode species, has emerged as a prominent experimental organism widely utilized in various biomedical research fields. However, the specific number of CVD-related genes and pathways within the C. elegans genome remains undisclosed to date, limiting its in-depth utilization for investigations. In the present study, we conducted a comprehensive analysis of genes and pathways related to CVD within the genomes of humans and C. elegans through a systematic bioinformatic approach. A total of 1113 genes in C. elegans orthologous to the most significant CVD-related genes in humans were identified, and the GO terms and pathways were compared to study the pathways that are conserved between the two species. In order to infer the functions of CVD-related orthologous genes in C. elegans, a PPI network was constructed. Orthologous gene PPI network analysis results reveal the hubs and important KRs: pmk-1, daf-21, gpb-1, crh-1, enpl-1, eef-1G, acdh-8, hif-1, pmk-2, and aha-1 in C. elegans. Modules were identified for determining the role of the orthologous genes at various levels in the created network. We also identified 9 commonly enriched pathways between humans and C. elegans linked with CVDs that include autophagy (animal), the ErbB signaling pathway, the FoxO signaling pathway, the MAPK signaling pathway, ABC transporters, the biosynthesis of unsaturated fatty acids, fatty acid metabolism, glutathione metabolism, and metabolic pathways. This study provides the first systematic genomic approach to explore the CVD-associated genes and pathways that are present in C. elegans, supporting the use of C. elegans as a prominent animal model organism for cardiovascular diseases.

HSP70 Is a Critical Regulator of HSP90 Inhibitor's Effectiveness in Preventing HCl-Induced Chronic Lung Injury and Pulmonary Fibrosis

Exposure to hydrochloric acid (HCl) can provoke acute and chronic lung injury. Because of its extensive production for industrial use, frequent accidental exposures occur, making HCl one of the top five chemicals causing inhalation injuries. There are no Food and Drug Administration (FDA)-approved treatments for HCl exposure. Heat shock protein 90 (HSP90) inhibitors modulate transforming growth factor-β (TGF-β) signaling and the development of chemical-induced pulmonary fibrosis. However, little is known on the role of Heat Shock Protein 70 (HSP70) during injury and treatment with HSP90 inhibitors. We hypothesized that administration of geranylgeranyl-acetone (GGA), an HSP70 inducer, or gefitinib (GFT), an HSP70 suppressant, alone or in combination with the HSP90 inhibitor, TAS-116, would improve or worsen, respectively, HCl-induced chronic lung injury in vivo and endothelial barrier dysfunction in vitro. GGA, alone, improved HCl-induced human lung microvascular endothelial cells (HLMVEC) barrier dysfunction and, in combination with TAS-116, improved the protective effect of TAS-116. In mice, GGA reduced HCl toxicity and while TAS-116 alone blocked HCl-induced chronic lung injury, co-administration with GGA, resulted in further improvement. Conversely, GFT potentiated HCl-induced barrier dysfunction and impaired the antidotal effects of TAS-116. We conclude that combined treatments with HSP90 inhibitors and HSP70 inducers may represent a novel therapeutic approach to manage HCl-induced chronic lung injury and pulmonary fibrosis.

Conserved Cardiovascular Network: Bioinformatics Insights into Genes and Pathways for Establishing Caenorhabditis elegans as an Animal Model for Cardiovascular Diseases

Cardiovascular disease (CVD) is a collective term for disorders of the heart and blood vessels. The molecular events and biochemical pathways associated with CVD are difficult to study in clinical settings on patients and in vitro conditions. Animal models play a pivotal and indispensable role in cardiovascular disease (CVD) research. Caenorhabditis elegans , a nematode species, has emerged as a prominent experimental organism widely utilised in various biomedical research fields. However, the specific number of CVD-related genes and pathways within the C. elegans genome remains undisclosed to date, limiting its in-depth utilisation for investigations. In the present study, we conducted a comprehensive analysis of genes and pathways related to CVD within the genomes of humans and C. elegans through a systematic bioinformatic approach. A total of 1113 genes in C. elegans orthologous to the most significant CVD-related genes in humans were identified, and the GO terms and pathways were compared to study the pathways that are conserved between the two species. In order to infer the functions of CVD-related orthologous genes in C. elegans, a PPI network was constructed. Orthologous gene PPI network analysis results reveal the hubs and important KRs: pmk-1, daf-21, gpb-1, crh-1, enpl-1, eef-1G, acdh-8, hif-1, pmk-2, and aha-1 in C. elegans. Modules were identified for determining the role of the orthologous genes at various levels in the created network. We also identified 9 commonly enriched pathways between humans and C. elegans linked with CVDs that include autophagy (animal), the ErbB signalling pathway, the FoxO signalling pathway, the MAPK signalling pathway, ABC transporters, the biosynthesis of unsaturated fatty acids, fatty acid metabolism, glutathione metabolism, and metabolic pathways. This study provides the first systematic genomic approach to explore the CVD-associated genes and pathways that are present in C. elegans, supporting the use of C. elegans as a prominent animal model organism for cardiovascular diseases.

Extracellular Hsp90 Binds to and Aligns Collagen-1 to Enhance Breast Cancer Cell Invasiveness

Cancer cell-secreted eHsp90 binds and activates proteins in the tumor microenvironment crucial in cancer invasion. Therefore, targeting eHsp90 could inhibit invasion, preventing metastasis-the leading cause of cancer-related mortality. Previous eHsp90 studies have solely focused on its role in cancer invasion through the 2D basement membrane (BM), a form of extracellular matrix (ECM) that lines the epithelial compartment. However, its role in cancer invasion through the 3D Interstitial Matrix (IM), an ECM beyond the BM, remains unexplored. Using a Collagen-1 binding assay and second harmonic generation (SHG) imaging, we demonstrate that eHsp90 directly binds and aligns Collagen-1 fibers, the primary component of IM. Furthermore, we show that eHsp90 enhances Collagen-1 invasion of breast cancer cells in the Transwell assay. Using Hsp90 conformation mutants and inhibitors, we established that the Hsp90 dimer binds to Collagen-1 via its N-domain. We also demonstrated that while Collagen-1 binding and alignment are not influenced by Hsp90's ATPase activity attributed to the N-domain, its open conformation is crucial for increasing Collagen-1 alignment and promoting breast cancer cell invasion. These findings unveil a novel role for eHsp90 in invasion through the IM and offer valuable mechanistic insights into potential therapeutic approaches for inhibiting Hsp90 to suppress invasion and metastasis.

Identification of hub genes associated with oxidative stress in heart failure and their correlation with immune infiltration using bioinformatics analysis

Both oxidative stress and the immune response are associated with heart failure (HF). In this study, our aim was to identify the hub genes associated with oxidative stress andimmune infiltration of HF by bioinformatics analysis and experimental verification. The expression profile of GSE36074 was obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were screened by GEO2R. The genes related to oxidative stress were extracted from GeneCards websites. Then, the functional enrichment analysis of oxidative stress-related DEGs (OSRDEGs) was performed using DAVID. In addition, we constructed a protein-protein interaction (PPI) network using the STRING database and screened for hub genes with Cytoscape software. We also used CIBERSORTx to analyze immune infiltration in mice heart tissues between the TAC and Sham groups and explored the correlation between immune cells and hub genes. Finally, the hub genes were carried out using reverse transcription quantitative PCR (RT-qPCR), immunohistochemistry (IHC) and western blot. A total of 136 OSRDEGs were found in GSE36074. Enrichment analysis revealed that these OSRDEGs were enriched in the mitochondrion, HIF-1, FoxO, MAPK and TNF signaling pathway. The five hub genes (Mapk14, Hif1a, Myc, Hsp90ab1, and Hsp90aa1) were screened by the cytoHubba plugin. The correlation analysis between immune cells and hub genes showed that Mapk14 was positively correlated with Th2 Cells, while Hif1a and Hsp90ab1exhibited a negative correlation with Th2 Cells; Myc exhibited a negative correlation with Monocytes; whereas, Hsp90aa1 was negatively correlated with NK Resting. Finally, five hub genes were validated by RT-qPCR, IHC and western blot. Mapk14, Hif1a, Myc, Hsp90ab1, and Hsp90aa1 are hub genes of HF and may play a critical role in the oxidative stress of HF. This study may provide new targets for the treatment of HF, and the potential immunotherapies are worthy of further study.

Analysis of the potential biological mechanisms of diosmin against renal fibrosis based on network pharmacology and molecular docking approach

BACKGROUND

Interstitial fibrosis is involved in the progression of various chronic kidney diseases and renal failure. Diosmin is a naturally occurring flavonoid glycoside that has antioxidant, anti-inflammatory, and antifibrotic activities. However, whether diosmin protects kidneys by inhibiting renal fibrosis is unknown.

METHODS

The molecular formula of diosmin was obtained, targets related to diosmin and renal fibrosis were screened, and interactions among overlapping genes were analyzed. Overlapping genes were used for gene function and KEGG pathway enrichment analysis. TGF-β1 was used to induce fibrosis in HK-2 cells, and diosmin treatment was administered. The expression levels of relevant mRNA were then detected.

RESULTS

Network analysis identified 295 potential target genes for diosmin, 6828 for renal fibrosis, and 150 hub genes. Protein-protein interaction network results showed that CASP3, SRC, ANXA5, MMP9, HSP90AA1, IGF1, RHOA, ESR1, EGFR, and CDC42 were identified as key therapeutic targets. GO analysis revealed that these key targets may be involved in the negative regulation of apoptosis and protein phosphorylation. KEGG indicated that pathways in cancer, MAPK signaling pathway, Ras signaling pathway, PI3K-Akt signaling pathway, and HIF-1 signaling pathway were key pathways for renal fibrosis treatment. Molecular docking results showed that CASP3, ANXA5, MMP9, and HSP90AA1 stably bind to diosmin. Diosmin treatment inhibited the protein and mRNA levels of CASP3, MMP9, ANXA5, and HSP90AA1. Network pharmacology analysis and experimental results suggest that diosmin ameliorates renal fibrosis by decreasing the expression of CASP3, ANXA5, MMP9, and HSP90AA1.

CONCLUSIONS

Diosmin has a potential multi-component, multi-target, and multi-pathway molecular mechanism of action in the treatment of renal fibrosis. CASP3, MMP9, ANXA5, and HSP90AA1 might be the most important direct targets of diosmin.

Emerging role of heat shock proteins in cardiovascular diseases

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

New evidence of genetic heterogeneity causing hereditary gingival fibromatosis and ALK and CD36 as new candidate genes

BACKGROUND

Hereditary gingival fibromatosis (HGF) is an uncommon genetic condition characterized by slow but progressive fibrous, non-hemorrhagic, and painless growth of the gingival tissues due to the increased deposition of collagen and other macromolecules of the extracellular matrix. HGF occurs in approximately 1:750,000 individuals and can exhibit dominant or recessive inheritance. To date, five loci (2p21-p22, 2p22.3-p23.3, 4q12, 5q13-q22, and 11p15) and three genes [REST (RE1-silencing transcription factor), SOS1 (Son-of-Sevenless-1), and ZNF862 (zinc finger protein 862 gene)] have been associated with HGF. Here, our study aimed to identify genetic variants associated with HGF by applying whole-exome sequencing (WES) and bioinformatics analyses.

METHODS

Thirteen Brazilian individuals with HGF and nine relatives without HGF from four unrelated families were chosen for our investigation. Blood collected from the patients and their relatives were used for WES. Five Web-available tools, namely, CADD, PolyPhen, SIFT, Mutation Taster, and Franklin's algorithms, were used to predict protein damage.

RESULTS

WES revealed pathogenic variants affecting the known HGF genes REST (c.1491_1492delAG) and SOS1 (c.3265_3266insTAAC) in two families. Additionally, potentially pathogenic variants segregating in the other two families were mapped to ALK receptor tyrosine kinase gene (ALK) (c.361C > T) and to collagen type I receptor and thrombospondin receptor gene (CD36) (c.1133G > T).

CONCLUSION

Our findings reinforce the high genetic heterogeneity of HGF, identifying new variants in HGF known genes (REST and SOS1) and ALK and CD36 as new genes that cause HGF.

Reprogramming the tumor microenvironment to improve the efficacy of cancer immunotherapies

The immunotherapeutic approaches based on checkpoint inhibitors, tumor vaccination, immune cell-based therapy, and cytokines were developed to engage the patient's immune system against cancer and better survival of them. While potent, however, preclinical and clinical data have identified that abnormalities in the tumor microenvironment (TME) can affect the efficacy of immunotherapies in some cancers. It is therefore imperative to develop new therapeutic interventions that will enable to overcome tumor-supportive TME and restrain anti-tumor immunity in patients that acquire resistance to current immunotherapies. Therefore, recognition of the essential nature of the tolerogenic TME may lead to a shift from the immune-suppressive TME to an immune-stimulating phenotype. Here, we review the composition of the TME and its effect on tumor immunoediting and then present how targeted monotherapy or combination therapies can be employed for reprogramming educated TME to improve current immunotherapies outcomes or elucidate potential therapeutic targets.

Targeting extracellular Hsp90: A unique frontier against cancer

The molecular chaperone Heat Shock Protein-90 (Hsp90) is known to interact with over 300 client proteins as well as regulatory factors (eg. nucleotide and proteins) that facilitate execution of its role as a chaperone and, ultimately, client protein activation. Hsp90 associates transiently with these molecular modulators during an eventful chaperone cycle, resulting in acquisition of flexible structural conformations, perfectly customized to the needs of each one of its client proteins. Due to the plethora and diverse nature of proteins it supports, the Hsp90 chaperone machinery is critical for normal cellular function particularly in response to stress. In diseases such as cancer, the Hsp90 chaperone machinery is hijacked for processes which encompass many of the hallmarks of cancer, including cell growth, survival, immune response evasion, migration, invasion, and angiogenesis. Elevated levels of extracellular Hsp90 (eHsp90) enhance tumorigenesis and the potential for metastasis. eHsp90 has been considered one of the new targets in the development of anti-cancer drugs as there are various stages of cancer progression where eHsp90 function could be targeted. Our limited understanding of the regulation of the eHsp90 chaperone machinery is a major drawback for designing successful Hsp90-targeted therapies, and more research is still warranted.

Gene expression and functional analysis of Aha1a and Aha1b in stress response in zebrafish

Activator of heat shock protein 90 (hsp90) ATPase (Aha1) is a Hsp90 co-chaperone required for Hsp90 ATPase activation. Aha1 is essential for yeast survival and muscle development in C. elegans under elevated temperature and hsp90-deficeiency induced stress conditions. The roles of Aha1 in vertebrates are poorly understood. Here, we characterized the expression and function of Aha1 in zebrafish. We showed that zebrafish genome contains two aha1 genes, aha1a and aha1b, that show distinct patterns of expression during development. Under the normal physiological conditions, aha1a is primarily expressed in skeletal muscle cells of zebrafish embryos, while aha1b is strongly expressed in the head region. aha1a and aha1b expression increased dramatically in response to heat shock induced stress. In addition, Aha1a-GFP fusion protein exhibited a dynamic translocation in muscle cells in response to heat shock. Moreover, upregulation of aha1 expression was also observed in hsp90a1 knockdown embryos that showed a muscle defect. Genetic studies demonstrated that knockout of aha1a, aha1b or both had no detectable effect on embryonic development, survival, and growth in zebrafish. The aha1a and aha1b mutant embryos showed normal muscle development and stress response in response to heat shock. Single or double aha1a and aha1b mutants could grow into normal reproductive adults with normal skeletal muscle structure and morphology compared with wild type control. Together, data from these studies indicate that Aha1a and Aha1b are involved in stress response. However, they are dispensable in zebrafish embryonic development, growth, and survival.

Profibrotic Role of Inducible Heat Shock Protein 90α Isoform in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease that affects skin and multiple internal organs. TGF-β, a central trigger of cutaneous fibrosis, activates fibroblasts with the involvement of the stress-inducible chaperone heat shock protein 90 isoform α (Hsp90α). Available evidence supports overexpression and secretion of Hsp90α as a feature in profibrotic pathological conditions. The aim of this work is to investigate the expression and function of Hsp90α in experimental models of skin fibrosis such as human fibroblasts, C57BL/6 mice, and in human SSc. For this purpose, we generated a new experimental model based on doxorubicin administration with improved characteristics with respect to the bleomycin model. We visualized disease progression in vivo by fluorescence imaging. In this work, we obtained Hsp90α mRNA overexpression in human skin fibroblasts, in bleomycin- and doxorubicin-induced mouse fibrotic skin, and in lungs of bleomycin- and doxorubicin-treated mice. Hsp90α-deficient mice showed significantly decreased skin thickness compared with wild-type mice in both animal models. In SSc patients, serum Hsp90α levels were increased in patients with lung involvement and in patients with the diffuse form of SSc (dSSc) compared with patients with the limited form of SSc. The serum Hsp90α levels of patients dSSc were correlated with the Rodnan score and the forced vital capacity variable. These results provide new supportive evidence of the contribution of the Hsp90α isoform in the development of skin fibrosis. In SSc, these results indicated that higher serum levels were associated with dSSc and lung fibrosis.

Extracellular Heat Shock Protein-90 (eHsp90): Everything You Need to Know

“Extracellular” Heat Shock Protein-90 (Hsp90) was initially reported in the 1970s but was not formally recognized until 2008 at the 4th International Conference on The Hsp90 Chaperone Machine (Monastery Seeon, Germany). Studies presented under the topic of “extracellular Hsp90 (eHsp90)” at the conference provided direct evidence for eHsp90’s involvement in cancer invasion and skin wound healing. Over the past 15 years, studies have focused on the secretion, action, biological function, therapeutic targeting, preclinical evaluations, and clinical utility of eHsp90 using wound healing, tissue fibrosis, and tumour models both in vitro and in vivo. eHsp90 has emerged as a critical stress-responding molecule targeting each of the pathophysiological conditions. Despite the studies, our current understanding of several fundamental questions remains little beyond speculation. Does eHsp90 indeed originate from purposeful live cell secretion or rather from accidental dead cell leakage? Why did evolution create an intracellular chaperone that also functions as a secreted factor with reported extracellular duties that might be (easily) fulfilled by conventional secreted molecules? Is eHsp90 a safer and more optimal drug target than intracellular Hsp90 chaperone? In this review, we summarize how much we have learned about eHsp90, provide our conceptual views of the findings, and make recommendations on the future studies of eHsp90 for clinical relevance.

Decellularization of tumours: A new frontier in tissue engineering

Cancer is one of the leading causes of death worldwide. The tumour extracellular matrix (ECM) has unique features in terms of composition and mechanical properties, resulting in a structurally and chemically different ECM to that of native, healthy tissues. This paper reviews to date the efforts into decellularization of tumours, which in the authors’ view represents a new frontier in the ever evolving field of tumour tissue engineering. An overview of the ECM and its importance in cancer is given, ending with examples of research using decellularized tumours, which has already indicated potential therapeutic targets, unravelled malignancy mechanisms or response to chemotherapy agents. The review highlights that more research is needed in this area, which can answer important questions related to tumour formation and progression to ultimately identify new and effective therapeutic targets. Within the near-future of personalized medicine, this research can create patient-specific tumour models and therapeutic regimes.

Multivariable prognostic model for heart failure in Chinese Han population-based setting

Aims

The prognosis of heart failure (HF) depends on genetic predisposition, and recent studies have shown that impaired autophagy is involved in HF. This study was aimed to construct a prognostic model combining polygenetic background based on the autophagy pathway and other traditional risk factors (TRF) of HF prognosis.

Methods and results

Via re‐analysing the transcriptomic data of 50 failing and 14 non‐failing donors, differentially expressed autophagy‐related genes (ARGs) were chosen for further comparison and analysis with whole exome sequencing and follow‐up data of 1000 HF patients. By searching from reported articles, prognosis‐related polymorphisms were identified. ARGs and prognosis‐related polymorphisms were used to develop genetic risk score (GRS) and genetic risk factor (GRF), respectively. We compared the predictive power of five models [Model 1, GRS; Model 2, composite of TRF and N‐terminal B‐type natriuretic peptide (NT‐proBNP); Model 3, composite of TRF, NT‐proBNP, and GRS; Model 4, composite of TRF, NT‐proBNP, and GRF; and Model 5, composite of TRF, NT‐proBNP, GRF, and GRS] by applying receiver operating characteristic curves. Twenty‐four prognosis‐related polymorphisms were used to construct GRF and 11 variants among 48 differentially expressed ARGs associated with clinical outcomes of HF patients were applied for GRS. GRS was strongly associated with cardiac mortality of HF patients, independent of TRF and GRF (95% confidence interval 1.273–1.739, P = 5.78 × 10⁻⁷). Comparing with patients with lowest GRS tertile, those with highest tertile had higher risks of developing worse clinical outcomes (hazard ratio = 1.866; 95% confidence interval 1.352–2.575, P = 1.47 × 10⁻⁴). The discrimination power of the model including GRS, TRF, GRF, and NT‐proBNP is most considerable (area under curve = 0.777), especially in men, patients over 60, patients with hypertension, patients without diabetes or hyperlipidaemia.

Conclusions

The model combining autophagy‐related GRS, TRF, GRF, and NT‐proBNP performs well in distinguishing between worse‐prognosis and better‐prognosis HF patients, leading a promising strategy for HF treatment and HF prevention.

Myocardial Proteomics Based on Smart Fog Computing and Its Application in Sports

How to strengthen physical fitness to improve the effect and efficiency of sports is an important research direction worthy of research. In response to these problems and limitations, Smart Fog Computing technology is introduced in this paper. Taking rats as the research object, the effective quantitative analysis and research of aerobic exercise on myocardial proteome are achieved through combining the business scope of myocardial proteomics, and connecting corresponding continuous aerobic exercises, verified by simulation analysis. The simulation research results show that the smart fog calculation is effective. For moderate-intensity aerobic exercise, the expression and intensity of the corresponding myocardial protein are changed significantly, and the corresponding heart becomes larger; meanwhile, moderate aerobic exercise can improve the metabolism and enhance digestive ability.

Hsp90 Levels in Idiopathic Inflammatory Myopathies and Their Association With Muscle Involvement and Disease Activity: A Cross-Sectional and Longitudinal Study

Background

Heat shock proteins (Hsp) are chaperones playing essential roles in skeletal muscle physiology, adaptation to exercise or stress, and activation of inflammatory cells. We aimed to assess Hsp90 in patients with idiopathic inflammatory myopathies (IIM) and its association with IIM-related features.

Methods

Hsp90 plasma levels were analyzed in a cross-sectional cohort (277 IIM patients and 157 healthy controls [HC]) and two longitudinal cohorts to assess the effect of standard-of-care pharmacotherapy (n=39 in early disease and n=23 in established disease). Hsp90 and selected cytokines/chemokines were measured by commercially available ELISA and human Cytokine 27-plex Assay.

Results

Hsp90 plasma levels were increased in IIM patients compared to HC (median [IQR]: 20.2 [14.3–40.1] vs 9.8 [7.5–13.8] ng/mL, p<0.0001). Elevated Hsp90 was found in IIM patients with pulmonary, cardiac, esophageal, and skeletal muscle involvement, with higher disease activity or damage, and with elevated muscle enzymes and crucial cytokines/chemokines involved in the pathogenesis of myositis (p<0.05 for all). Plasma Hsp90 decreased upon pharmacological treatment in both patients with early and established disease. Notably, Hsp90 plasma levels were slightly superior to traditional biomarkers, such as C-reactive protein and creatine kinase, in differentiating IIM from HC, and IIM patients with cardiac involvement and interstitial lung disease from those without these manifestations.

Conclusions

Hsp90 is increased systemically in patients with IIM. Plasma Hsp90 could become an attractive soluble biomarker of disease activity and damage and a potential predictor of treatment response in IIM.

HSP90 as a regulator of extracellular matrix dynamics

The extracellular matrix (ECM) is a dynamic and organised extracellular network assembled from proteins and carbohydrates exported from the cell. The ECM is critical for multicellular life, providing spatial and temporal cellular cues to maintain tissue homeostasis. Consequently, ECM production must be carefully balanced with turnover to ensure homeostasis; ECM dysfunction culminates in disease. Hsp90 is a molecular chaperone central to protein homeostasis, including in the ECM. Intracellular and extracellular Hsp90 isoforms collaborate to regulate the levels and status of proteins in the ECM via multiple mechanisms. In so doing, Hsp90 regulates ECM dynamics, and changes in Hsp90 levels or activity support the development of ECM-related diseases, like cancer and fibrosis. Consequently, Hsp90 levels may have prognostic value, while inhibition of Hsp90 may have therapeutic potential in conditions characterised by ECM dysfunction.

The Potential of Hsp90 in Targeting Pathological Pathways in Cardiac Diseases

Heat shock protein 90 (Hsp90) is a molecular chaperone that interacts with up to 10% of the proteome. The extensive involvement in protein folding and regulation of protein stability within cells makes Hsp90 an attractive therapeutic target to correct multiple dysfunctions. Many of the clients of Hsp90 are found in pathways known to be pathogenic in the heart, ranging from transforming growth factor β (TGF-β) and mitogen activated kinase (MAPK) signaling to tumor necrosis factor α (TNFα), G_s and G_q g-protein coupled receptor (GPCR) and calcium (Ca²⁺) signaling. These pathways can therefore be targeted through modulation of Hsp90 activity. The activity of Hsp90 can be targeted through small-molecule inhibition. Small-molecule inhibitors of Hsp90 have been found to be cardiotoxic in some cases however. In this regard, specific targeting of Hsp90 by modulation of post-translational modifications (PTMs) emerges as an attractive strategy. In this review, we aim to address how Hsp90 functions, where Hsp90 interacts within pathological pathways, and current knowledge of small molecules and PTMs known to modulate Hsp90 activity and their potential as therapeutics in cardiac diseases.

Overcoming physical stromal barriers to cancer immunotherapy

Immunotherapy has emerged as an unprecedented hope for the treatment of notoriously refractory cancers. Numerous investigational drugs and immunotherapy-including combination regimens are under preclinical and clinical investigation. However, only a small patient subpopulation across different types of cancer responds to the therapy due to the presence of several mechanisms of resistance. There have been extensive efforts to overcome this limitation and to expand the patient population that could be benefited by this state-of-the-art therapeutic modality. Among various causes of the resistance, we here focus on physical stromal barriers that impede the access of immunotherapeutic drug molecules and/or native and engineered immune cells to cancer tissues and cells. Two primary stromal barriers that contribute to the resistance include aberrant tumor vasculatures and excessive extracellular matrix build-ups that restrict extravasation and infiltration, respectively, of molecular and cellular immunotherapeutic agents into tumor tissues. Here, we review the features of these barriers that limit the efficacy of immunotherapy and discuss recent advances that could potentially help immunotherapy overcome the barriers and improve therapeutic outcomes.

Correlative 3D cryo X-ray imaging reveals intracellular location and effect of designed antifibrotic protein-nanomaterial hybrids

Revealing the intracellular location of novel therapeutic agents is paramount for the understanding of their effect at the cell ultrastructure level. Here, we apply a novel correlative cryo 3D imaging approach to determine the intracellular fate of a designed protein–nanomaterial hybrid with antifibrotic properties that shows great promise in mitigating myocardial fibrosis. Cryo 3D structured illumination microscopy (cryo-3D-SIM) pinpoints the location and cryo soft X-ray tomography (cryo-SXT) reveals the ultrastructural environment and subcellular localization of this nanomaterial with spatial correlation accuracy down to 70 nm in whole cells. This novel high resolution 3D cryo correlative approach unambiguously locates the nanomaterial after overnight treatment within multivesicular bodies which have been associated with endosomal trafficking events by confocal microscopy. Moreover, this approach allows assessing the cellular response towards the treatment by evaluating the morphological changes induced. This is especially relevant for the future usage of nanoformulations in clinical practices. This correlative super-resolution and X-ray imaging strategy joins high specificity, by the use of fluorescence, with high spatial resolution at 30 nm (half pitch) provided by cryo-SXT in whole cells, without the need of staining or fixation, and can be of particular benefit to locate specific molecules in the native cellular environment in bio-nanomedicine.

A novel 3D cryo correlative approach locates designed therapeutic protein–nanomaterial hybrids in whole cells with high specificity and resolution. Detection of treatment-induced morphological changes, crucial for pre-clinical studies, are revealed.

Heat Shock Proteins: Connectors between Heart and Kidney

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

Association of heat shock protein polymorphisms with patient susceptibility to coronary artery disease comorbid depression and anxiety in a Chinese population

Background

Coronary artery disease (CAD) is one of the severe diseases that threaten human health worldwide. In addition, the associated rate of comorbidity with depression and anxiety is extremely high. Heat shock proteins (HSPs) are a group of proteins that possesses cardiovascular and psychological protection properties. The objective of this study is to determine the association of the two most widely studied HSPs, namely, HSP70 and HSP90, with CAD comorbid depression and anxiety in a Chinese population.

Methods

A case-control study involving 271 CAD patients and 113 healthy individuals was conducted. The 271 CAD patients include individuals with (123) and without depression (148) and individuals with (57) and without anxiety (214). Ten single nucleotide polymorphisms (SNPs) for HSP70 and seven SNPs for HSP90 were selected and genotyped.

Results

Results revealed that the HSP70 rs10892958 C allele and HSP70 rs2236658 T allele were associated with a decreased risk of CAD (P < 0.05), whereas the G allele of the rs11218941 polymorphism was associated with an increased risk of CAD. The haplotype analysis results indicated that the haplotype TGGGC of the HSPA8 gene (coded the HSP70 family, rs4936770/rs4802/rs10892958/rs11218941/rs2236658) significantly increased the risk of CAD (P = 0.008). Among the patients with CAD, the carriers of the CC genotype for the HSP90 rs1042665 showed higher risks of anxiety than the carriers of another genotypes. However, no significant relationships were found among the CAD with depression and CAD without depression groups for the selected SNPs. These findings suggested that the genetic polymorphisms in the HSP gene, especially the HSPA8 of HSP70, contribute to CAD susceptibility and rs1042665 genetic polymorphisms might have an effect on the anxiety incidence among CAD patients.

Systemic sclerosis biomarkers detection in the secretome of TGFβ1-activated primary human lung fibroblasts

TGFβ1 is a profibrotic mediator that contributes to a broad spectrum of pathologies, including systemic sclerosis-associated pulmonary fibrosis (SSc-PF). However, the secretome of TGFβ1-stimulated primary human normal lung (NL) fibroblasts has not been well characterized. Using fluorescent 2-dimensional gel electrophoresis (2D-PAGE) and differential gel electrophoresis (DIGE) followed by Mass Spectrometry, we identified 37 differentially secreted proteins in the conditioned media of TGFβ1-activated NL fibroblasts and generated a protein-protein association network of the TGFβ1 secretome using STRING. Functional enrichment revealed that several biological processes and pathways characteristic of PF were enriched. Additionally, by comparing the TGFβ1 secretome of NL fibroblasts to proteomic biomarkers from biological fluids of systemic sclerosis (SSc) patients, we identified 11 overlapping proteins. Together our data validate the TGFβ1-induced secretome of NL fibroblasts as a valid in vitro model that reflects SSc biomarkers and identify potential therapeutic targets for SSc-PF. SIGNIFICANCE: All proteins secreted by fibroblasts into the extracellular space, representing the secretome, promote cell-to-cell communication as well as tissue homeostasis, immune mechanisms, developmental regulation, proteolysis, development of the extracellular matrix (ECM) and cell adhesion. Therefore, it is crucial to understand how TGFβ1, a well-known profibrotic cytokine, modulates the secretome of pulmonary fibroblasts, and how the TGFβ1-induced secretome resembles biomarkers in SSc. Using functional enrichment analysis, key pathways and hub proteins can be identified and studied as potential therapeutic targets for pulmonary fibrosis.

Heat shock protein 90 inhibitor ameliorates pancreatic fibrosis by degradation of transforming growth factor-β receptor

BACKGROUND AND AIM

Pancreatic fibrosis increases pancreatic cancer risk in chronic pancreatitis (CP). Pancreatic stellate cells (PSCs) play a critical role in pancreatic fibrosis by transforming growth factor-β (TGFβ) has been shown to inhibit transforming growth factor-β receptor (TGFβR)-mediated Smad and no-Smad signaling pathways. Thus, the effects of Hsp90 inhibitor on pancreatic fibrosis are evaluated in CP mice, and the association between Hsp90 and biological functions of PSCs is further investigated in vitro.

METHODS

The effects of Hsp90 inhibitor 17AAG on pancreatic fibrosis were assessed in caerulein-induced CP mice, and primary PSCs were used to determine the role of Hsp90 inhibitor 17AAG in vitro.

RESULTS

We observed increased expression of Hsp90 in pancreatic tissues of caerulein-induced CP mice. Hsp90 inhibitor 17AAG ameliorated pancreatic inflammation and fibrosis in caerulein-induced CP mice. In vitro, Hsp90 inhibitor 17AAG inhibited TGFβ1-induced activation and extracellular matrix accumulation of PSCs by blocking TGFβR-mediated Smad2/3 and PI3K /Akt/GSK-3β signaling pathways.Hsp90 inhibitor 17AAG degraded TGFβRII by a ubiquitin-proteasome pathway, co-immunoprecipitation showed an interaction between Hsp90 and TGFβRII in PSCs.

CONCLUSIONS

The study suggests that an Hsp90 inhibitor 17AAG remarkable prevents the development of pancreatic fibrosis in caerulein-induced CP mice, and suppresses activation and extracellular matrix accumulation of PSCs in vitro. The current results provide a potential treatment strategy based on Hsp90 inhibition for pancreatic fibrosis in CP.

The role of heat shock proteins in the regulation of fibrotic diseases

Heat shock proteins (HSPs) are key players to restore cell homeostasis and act as chaperones by assisting the folding and assembly of newly synthesized proteins and preventing protein aggregation. Recently, evidence has been accumulating that HSPs have been proven to have other functions except for the classical molecular chaperoning in that they play an important role in a wider range of fibrotic diseases via modulating cytokine induction and inflammation response, including lung fibrosis, liver fibrosis, and idiopathic pulmonary fibrosis. The recruitment of inflammatory cells, a large number of secretion of pro-fibrotic cytokines such as transforming growth factor-β1 (TGF-β1) and increased apoptosis, oxidative stress, and proteasomal system degradation are all events occurring during fibrogenesis, which might be associated with HSPs. However, their role on fibrotic process is not yet fully understood. In this review, we discuss new discoveries regarding the involvement of HSPs in the regulation of organ and tissue fibrosis, and note recent findings suggesting that HSPs may be a promising therapeutic target for improving the current frustrating outcome of fibrotic disorders.

Engineering multifunctional metal/protein hybrid nanomaterials as tools for therapeutic intervention and high-sensitivity detection

Protein-based hybrid nanomaterials have recently emerged as promising platforms to fabricate tailored multifunctional biologics for biotechnological and biomedical applications. This work shows a simple, modular, and versatile strategy to design custom protein hybrid nanomaterials. This approach combines for the first time the engineering of a therapeutic protein module with the engineering of a nanomaterial-stabilizing module within the same molecule, resulting in a multifunctional hybrid nanocomposite unachievable through conventional material synthesis methodologies. As the first proof of concept, a multifunctional system was designed ad hoc for the therapeutic intervention and monitoring of myocardial fibrosis. This hybrid nanomaterial combines a designed Hsp90 inhibitory domain and a metal nanocluster stabilizing module resulting in a biologic drug labelled with a metal nanocluster. The engineered nanomaterial actively reduced myocardial fibrosis and heart hypertrophy in an animal model of cardiac remodeling. In addition to the therapeutic effect, the metal nanocluster allowed for in vitro, ex vivo, and in vivo detection and imaging of the fibrotic disease under study. This study evidences the potential of combining protein engineering and protein-directed nanomaterial engineering approaches to design custom nanomaterials as theranostic tools, opening up unexplored routes to date for the next generation of advanced nanomaterials in medicine.

Engineering protein-based hybrids by combining protein engineering and nanotechnology: a protein-nanocluster hybrid for theranostic use in myocardial fibrosis shows the potential to create tailored multifunctional biologics for biomedicine.

Influenza A Virus Induces Autophagy by Its Hemagglutinin Binding to Cell Surface Heat Shock Protein 90AA1

Autophagy can be utilized by the influenza A virus (IAV) to facilitate its replication. However, whether autophagy is induced at the stage of IAV entry is still unclear. Here, we report that IAV induces autophagy by hemagglutinin (HA) binding to heat shock protein 90AA1 (HSP90AA1) distributed on the cell surface. Virus overlay protein binding assay and pull-down assay indicated that IAV HA bound directly to cell surface HSP90AA1. Knockdown of HSP90AA1 weakened H1N1 infection. Incubation of IAV viral particles with recombinant HSP90AA1 or prior blockade of A549 cells with an anti-HSP90AA1 antibody could inhibit attachment of IAV. Moreover, we found that recombinant HA1 protein binding to cell surface HSP90AA1 was sufficient to induce autophagy through the AKT-MTOR pathway. Our study reveals that the HSP90AA1 on cell surface participates in IAV entry by directing binding to the HA1 subunit of IAV and subsequently induces autophagy.

Integrative Analysis Revealing Human Heart-Specific Genes and Consolidating Heart-Related Phenotypes

Elucidating expression patterns of heart-specific genes is crucial for understanding developmental, physiological, and pathological processes of the heart. The aim of the present study is to identify functionally and pathologically important heart-specific genes by performing the Ingenuity Pathway Analysis (IPA). Through a median-based analysis of tissue-specific gene expression based on the Genotype-Tissue Expression (GTEx) data, we identified 56 genes with heart-specific or elevated expressions in the heart (heart-specific/enhanced), among which three common heart-specific/enhanced genes and four atrial appendage-specific/enhanced genes were unreported regarding the heart. Differential expression analysis further revealed 225 differentially expressed genes (DEGs) between atrial appendage and left ventricle. Our integrative analyses of those heart-specific/enhanced genes and DEGs with IPA revealed enriched heart-related traits and diseases, consolidating evidence of relationships between these genes and heart function. Our reports on comprehensive identification of heart-specific/enhanced genes and DEGs and their relation to pathways associated with heart-related traits and diseases provided molecular insights into essential regulators of cardiac physiology and pathophysiology and potential new therapeutic targets for heart diseases.

HSP90 Inhibition and Modulation of the Proteome: Therapeutical Implications for Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic Pulmonary fibrosis (IPF) is a catastrophic disease with poor outcomes and limited pharmacological approaches. Heat shock protein 90 (HSP90) has been recently involved in the wound-healing pathological response that leads to collagen deposition in patients with IPF and its inhibition represents an exciting drug target against the development of pulmonary fibrosis. Under physiological conditions, HSP90 guarantees proteostasis through the refolding of damaged proteins and the degradation of irreversibly damaged ones. Additionally, its inhibition, by specific HSP90 inhibitors (e.g., 17 AAG, 17 DAG, and AUY-922) has proven beneficial in different preclinical models of human disease. HSP90 inhibition modulates a complex subset of kinases and interferes with intracellular signaling pathways and proteome regulation. In this review, we evaluated the current evidence and rationale for the use of HSP90 inhibitors in the treatment of pulmonary fibrosis, discussed the intracellular pathways involved, described the limitations of the current understanding and provided insights for future research.

Blocking Extracellular Chaperones to Improve Cardiac Regeneration

Chronic or acute insults to the myocardium are responsible for the onset of cardiomyopathy and heart failure. Due to the poor regenerative ability of the human adult heart, the survival of cardiomyocytes is a prerequisite to support heart function. Chaperone proteins, by regulating sarcomeric protein folding, function, and turnover in the challenging environment of the beating heart, play a fundamental role in myocardial physiology. Nevertheless, a number of evidences indicate that, under stress conditions or during cell damage, myocardial cells release chaperone proteins that, from the extracellular milieu, play a detrimental function, by perpetuating inflammation and inducing cardiomyocyte apoptosis. Blocking the activity of extracellular chaperones has been proven to have beneficial effects on heart function in preclinical models of myocardial infarction and cardiomyopathy. The application of this approach in combination with tissue engineering strategies may represent a future innovation in cardiac regenerative medicine.

Comprehensive molecular characterization of circRNA-associated ceRNA network in constrictive pericarditis

Background

Aberrant gene expression occurs in almost all diseases including constrictive pericarditis (CP). However, the dysregulation of genes underlying the CP remains unclear. This study aims to investigate the potential molecular mechanisms underlying CP and screen hub genes critical for the pathogenesis of CP.

Methods

Differentially expressed mRNAs, miRNAs, lncRNAs and circRNAs in pericardial tissues were screened using RNA-seq in CP patients and controls. Furthermore, functional annotation analysis and protein-protein interaction (PPI) network were carried out to investigate the potential key pathways and identify hub genes in CP. Subsequently, a ceRNA network was established and the key circRNAs were determined by Gene Set Enrichment Analysis (GSEA). Finally, the corresponding RNA-seq results were confirmed and validated with a quantitative real time-PCR (qRT-PCR).

Results

Functional annotation analysis revealed that differentially expressed mRNAs (DEMs) mainly participated in inflammatory response related pathways and the 10 top genes with the highest degree in PPI network were considered as the hub genes. In addition, a total of 377 regulatory relationships among the differentially expressed genes (DEGs) could be constructed, from which a subsequent ceRNA network was also established, while the circRNAs were further validated with qRT-PCR and the key biological pathways were identified using GSEA as well.

Conclusions

The genes determined to have altered expression levels in CP may participate in a number of biological signaling processes leading to inflammation and fibrosis frequently encountered in CP, and, therefore, our novel findings may provide an insight into the pathogenesis, molecular biomarkers, and potential therapeutic targets in CP.

Extracellular Matrix in the Tumor Microenvironment and Its Impact on Cancer Therapy

Solid tumors are complex organ-like structures that consist not only of tumor cells but also of vasculature, extracellular matrix (ECM), stromal, and immune cells. Often, this tumor microenvironment (TME) comprises the larger part of the overall tumor mass. Like the other components of the TME, the ECM in solid tumors differs significantly from that in normal organs. Intratumoral signaling, transport mechanisms, metabolisms, oxygenation, and immunogenicity are strongly affected if not controlled by the ECM. Exerting this regulatory control, the ECM does not only influence malignancy and growth of the tumor but also its response toward therapy. Understanding the particularities of the ECM in solid tumor is necessary to develop approaches to interfere with its negative effect. In this review, we will also highlight the current understanding of the physical, cellular, and molecular mechanisms by which the pathological tumor ECM affects the efficiency of radio-, chemo-, and immunotherapy. Finally, we will discuss the various strategies to target and modify the tumor ECM and how they could be utilized to improve response to therapy.

Pro-oxidant and pro-inflammatory effects of glycated albumin on cardiomyocytes

Human serum albumin (HSA) is the most abundant circulating protein in the body and presents an extensive range of biological functions. As such, it is prone to undergo post-translational modifications (PTMs). The non-enzymatic early glycation of HSA, one of the several PTMs undergone by HSA, arises from the addition of reducing sugars to amine group residues, thus modifying the structure of HSA. These changes may affect HSA functions impairing its biological activity, finally leading to cell damage. The aim of this study was to quantitate glycated-HSA (GA) levels in the plasma of heart failure (HF) patients and to evaluate the biological effects of GA on HL-1 cardiomyocytes. Plasma GA content from HF patients and healthy subjects was measured by direct infusion electrospray ionization mass spectrometry (ESI-MS). Results pointed out a significant increase of GA in HF patients with respect to the control group (p < 0.05). Additionally, after stimulation with GA, proteomic analysis of HL-1 secreted proteins showed the modulation of several proteins involved, among other processes, in the response to stress. Further, stimulated cells showed a rapid increase in ROS generation, higher mRNA levels of the inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), and higher levels of the oxidative 4-HNE-protein adducts and carbonylated proteins. Our findings show that plasma GA is increased in HF patients. Further, GA exerts pro-inflammatory and pro-oxidant effects on cardiomyocytes, which suggest a causal role in the etiopathogenesis of HF.

Interrelationship between diabetes mellitus and heart failure: the role of peroxisome proliferator-activated receptors in left ventricle performance

Heart failure (HF) is a common cardiac syndrome, whose pathophysiology involves complex mechanisms, some of which remain unknown. Diabetes mellitus (DM) constitutes not only a glucose metabolic disorder accompanied by insulin resistance but also a risk factor for cardiovascular disease and HF. During the last years though emerging data set up, a bidirectional interrelationship between these two entities. In the case of DM impaired calcium homeostasis, free fatty acid metabolism, redox state, and advance glycation end products may accelerate cardiac dysfunction. On the other hand, when HF exists, hypoperfusion of the liver and pancreas, b-blocker and diuretic treatment, and autonomic nervous system dysfunction may cause impairment of glucose metabolism. These molecular pathways may be used as therapeutic targets for novel antidiabetic agents. Peroxisome proliferator-activated receptors (PPARs) not only improve insulin resistance and glucose and lipid metabolism but also manifest a diversity of actions directly or indirectly associated with systolic or diastolic performance of left ventricle and symptoms of HF. Interestingly, they may beneficially affect remodeling of the left ventricle, fibrosis, and diastolic performance but they may cause impaired water handing, sodium retention, and decompensation of HF which should be taken into consideration in the management of patients with DM. In this review article, we present the pathophysiological data linking HF with DM and we focus on the molecular mechanisms of PPARs agonists in left ventricle systolic and diastolic performance providing useful insights in the molecular mechanism of this class of metabolically active regiments.

Reduction of cardiac TGFβ-mediated profibrotic events by inhibition of Hsp90 with engineered protein

Myocardial fibroblast activation coupled with extracellular matrix production is a pathological signature of myocardial fibrosis and is governed mainly by transforming growth factor TGFβ-Smad2/3 signaling. Targeting the ubiquitous TGFβ leads to cellular homeostasis deregulation with adverse consequences. We previously showed the anti-fibrotic effects upon downregulation of 90-kDa heat shock protein (Hsp90), a chaperone that associates to the TGFβ signaling cascade. In the present study, we use a fluorescent-labeled Hsp90 protein inhibitor (CTPR390-488) with specific Hsp90 binding properties to reduce myocardial pro-fibrotic events in vitro and in vivo. The mechanism of action involves the disruption of TGFβRI-Hsp90 complex, resulting in a decrease in TGFβ signaling and reduction in extracellular matrix collagen. In vivo, decreased myocardial collagen deposition was observed upon CTPR390-488 treatment in a pro-fibrotic mouse model. This is the first study demonstrating the ability of an engineered Hsp90 protein inhibitor to block collagen expression, reduce the motility of myocardial TGFβ-activated fibroblasts and ameliorate angiotensin-II induced cardiac myocardial fibrosis in vivo.

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

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

Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective

Many heat shock proteins (HSPs) are essential to survival as a consequence of their role as molecular chaperones, and play a critical role in maintaining cellular proteostasis by integrating the fundamental processes of protein folding and degradation. HSPs are arguably among the most prominent classes of proteins that have been broadly linked to many human disorders, with changes in their expression profile and/or intracellular/extracellular location now being described as contributing to the pathogenesis of a number of different diseases. Although the concept was initially controversial, it is now widely accepted that HSPs have additional biological functions over and above their role in proteostasis (so-called 'protein moonlighting'). Most importantly, these new insights are enlightening our understanding of biological processes in health and disease, and revealing novel and exciting therapeutic opportunities. This theme issue draws on therapeutic insights from established research on HSPs in cancer and other non-communicable disorders, with an emphasis on how the intracellular function of HSPs contrasts with their extracellular properties and function, and interrogates their potential diagnostic and therapeutic value to the prevention, management and treatment of chronic diseases.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

The protein-protein interaction network and clinical significance of heat-shock proteins in esophageal squamous cell carcinoma

Heat-shock proteins (HSPs), one of the evolutionarily conserved protein families, are widely found in various organisms, and play important physiological functions. Nevertheless, HSPs have not been systematically analyzed in esophageal squamous cell carcinoma (ESCC). In this study, we applied the protein-protein interaction (PPI) network methodology to explore the characteristics of HSPs, and integrate their expression in ESCC. First, differentially expressed HSPs in ESCC were identified from our previous RNA-seq data. By constructing a specific PPI network, we found differentially expressed HSPs interacted with hundreds of neighboring proteins. Subcellular localization analyses demonstrated that HSPs and their interacting proteins distributed in multiple layers, from membrane to nucleus. Functional enrichment annotation analyses revealed known and potential functions for HSPs. KEGG pathway analyses identified four significant enrichment pathways. Moreover, three HSPs (DNAJC5B, HSPA1B, and HSPH1) could serve as promising targets for prognostic prediction in ESCC, suggesting these HSPs might play a significant role in the development of ESCC. These multiple bioinformatics analyses have provided a comprehensive view of the roles of heat-shock proteins in esophageal squamous cell carcinoma.

A secreted Heat shock protein 90 of Trichomonas vaginalis

Trichomonas vaginalis is a causative agent of Trichomoniasis, a leading non-viral sexually transmitted disease worldwide. In the current study, we show Heat shock protein 90 is essential for its growth. Upon genomic analysis of the parasite, it was found to possess seven ORFs which could potentially encode Hsp90 isoforms. We identified a cytosolic Hsp90 homolog, four homologs which can align to truncated cytosolic Hsp90 gene products along with two Grp94 homologs (ER isoform of Hsp90). However, both Grp94 orthologs lacked an ER retention motif. In cancer cells, it is very well established that Hsp90 is secreted and regulates key clients involved in metastases, migration, and invasion. Since Trichomonas Grp94 lacks ER retention motif, we examined the possibility of its secretion. By using cell biology and biochemical approaches we show that the Grp94 isoform of Hsp90 is secreted by the parasite by the classical ER-Golgi pathway. This is the first report of a genome encoded secreted Hsp90 in a clinically important parasitic protozoan.

Hsp90 is an essential chaperone in eukaryotes and it is often described as a master regulator of cellular homeostasis. In addition to its well-known functions inside the cell, extracellular Hsp90 has also been implicated in migration and invasion of tumor cells. We have, for the first time, identified the presence of an extracellular Hsp90 in a parasitic protozoan, Trichomonas vaginalis. The extracellular Hsp90 is a Grp94 homolog that lacks a canonical ER retention signal. Our analysis of Grp94 sequences from protozoa shows that it is uncommon for a Grp94 to lack ER retention signal. In the current study, we characterized the biochemical parameters and established the extracellular localization of this Hsp90 paralog. This secreted Hsp90 in Trichomonas can potentially modulate host-pathogen interaction.

MicroRNA-495 inhibits the high glucose-induced inflammation, differentiation and extracellular matrix accumulation of cardiac fibroblasts through downregulation of NOD1

Background

MicroRNAs (miRNAs) have physiological and pathophysiological functions that are involved in the regulation of cardiac fibrosis. This study aimed to investigate the effects of miR-495 on high glucose-induced cardiac fibrosis in human cardiac fibroblasts (CFs) and to establish the mechanism underlying these effects.

Methods

Human CFs were transfected with an miR-495 inhibitor or mimic and incubated with high glucose. The levels of NOD1 and miR-495 were then determined via quantitative RT-PCR. Pro-inflammatory cytokine levels, cell differentiation and extracellular matrix accumulation were respectively detected using ELISA, quantitative RT-PCR and western blot assays. The luciferase reporter assay, quantitative RT-PCR and western blot were used to explore whether NOD1 was a target of miR-495. The effects of miR-495 on the NF-κB and TGF-β1/Smad signaling pathways were also detected via western blot.

Results

Our results show that high glucose can significantly increase the expression of NOD1 in a time-dependent manner. Upregulation of miR-495 significantly alleviated the high glucose-induced increases in cell differentiation and collagen accumulation of CFs. Moreover, the bioinformatics analysis predicted that NOD1 was a potential target gene for miR-495. The luciferase reporter assay showed that miR-495 can directly target NOD1. The introduction of miR-495 could significantly inhibit the high glucose-activated NF-κB and TGF-β1/Smad signaling pathways.

Conclusion

Upregulation of miR-495 ameliorates the high glucose-induced inflammatory, cell differentiation and extracellular matrix accumulation of human CFs by modulating both the NF-κB and TGF-β1/Smad signaling pathways through downregulation of NOD1 expression. These results provide further evidence for the protective effect of miR-495 overexpression in cases of high glucose-induced cardiac fibrosis.

HSP27 is a partner of JAK2-STAT5 and a potential therapeutic target in myelofibrosis

Heat shock protein 27 (HSP27/HSPB1) is a stress-inducible chaperone that facilitates cancer development by its proliferative and anti-apoptotic functions. The OGX-427 antisense oligonucleotide against HSP27 has been reported to be beneficial against idiopathic pulmonary fibrosis. Here we show that OGX-427 is effective in two murine models of thrombopoietin- and JAKV617F-induced myelofibrosis. OGX-427 limits disease progression and is associated with a reduction in spleen weight, in megakaryocyte expansion and, for the JAKV617F model, in fibrosis. HSP27 regulates the proliferation of JAK2V617F-positive cells and interacts directly with JAK2/STAT5. We also show that its expression is increased in both CD34⁺ circulating progenitors and in the serum of patients with JAK2-dependent myeloproliferative neoplasms with fibrosis. Our data suggest that HSP27 plays a key role in the pathophysiology of myelofibrosis and represents a new potential therapeutic target for patients with myeloproliferative neoplasms.

Myelofibrosis is a chronic degenerative disorder characterized by progressive bone marrow fibrosis. Here, the authors show that the chaperone HSP27 contributes to myelofibrosis via regulation of the JAK2/STAT5 pathway, and that antisense oligonucleotides targeting HSP27 are effective in two mouse models of the disease

Synergistic role of HSP90α and HSP90β to promote myofibroblast persistence in lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of the lung parenchyma, causing significant morbidity through worsening dyspnoea and overall functional decline. IPF is characterised by apoptosis-resistant myofibroblasts, which are a major source for the excessive production of extracellular matrix (ECM) overtaking normal lung tissue. We sought to study the role of heat shock protein (HSP) isoforms HSP90α and HSP90β, whose distinct roles in lung fibrogenesis remain elusive.We determined the level of circulating HSP90α in IPF patients (n=31) and age-matched healthy controls (n=9) by ELISA. The release of HSP90α and HSP90β was evaluated in vitro in primary IPF and control lung fibroblasts and ex vivo after mechanical stretch on fibrotic lung slices from rats receiving adenovector-mediated transforming growth factor-β1.We demonstrate that circulating HSP90α is upregulated in IPF patients in correlation with disease severity. The release of HSP90α is enhanced by the increase in mechanical stress of the fibrotic ECM. This increase in extracellular HSP90α signals through low-density lipoprotein receptor-related protein 1 (LRP1) to promote myofibroblast differentiation and persistence. In parallel, we demonstrate that the intracellular form of HSP90β stabilises LRP1, thus amplifying HSP90α extracellular action.We believe that the specific inhibition of extracellular HSP90α is a promising therapeutic strategy to reduce pro-fibrotic signalling in IPF.

Heat Shock Proteins in Vascular Diabetic Complications: Review and Future Perspective

Heat shock proteins (HSPs) are a large family of proteins highly conserved throughout evolution because of their unique cytoprotective properties. Besides assisting protein refolding and regulating proteostasis under stressful conditions, HSPs also play an important role in protecting cells from oxidative stress, inflammation, and apoptosis. Therefore, HSPs are crucial in counteracting the deleterious effects of hyperglycemia in target organs of diabetes vascular complications. Changes in HSP expression have been demonstrated in diabetic complications and functionally related to hyperglycemia-induced cell injury. Moreover, associations between diabetic complications and altered circulating levels of both HSPs and anti-HSPs have been shown in clinical studies. HSPs thus represent an exciting therapeutic opportunity and might also be valuable as clinical biomarkers. However, this field of research is still in its infancy and further studies in both experimental diabetes and humans are required to gain a full understanding of HSP relevance. In this review, we summarize current knowledge and discuss future perspective.

Molecular mechanism and targeted therapy of Hsp90 involved in lung cancer: New discoveries and developments (Review)

The exploration of the molecular mechanisms and signaling pathways on lung cancer is very important for developing new strategies of diagnosis and treatment to this disease, such as finding valuable lung cancer markers and molecularly targeted therapies. Previously, a number of studies disclose that heat shock protein 90 (Hsp90) is upregulated in cancer cells, tissues and serum of lung cancer patients, and its upregulation intimately correlates with the occurrence, development and outcome of lung cancer. On the contrary, inhibition of Hsp90 can suppress cell proliferation, motility and metastasis of lung cancer and promote apoptosis of lung cancer cells via complex signaling pathways. In addition, a series of Hsp90 inhibitors have been investigated as effective molecular targeted therapy tactics fighting against lung cancer. This review, systematically summarizes the role of Hsp90 in lung cancer, the molecular mechanisms and development of anti-Hsp90 treatment in lung cancer.

Serelaxin inhibits differentiation and fibrotic behaviors of cardiac fibroblasts by suppressing ALK-5/Smad2/3 signaling pathway

Serelaxin, a recombinant form of human relaxin-2, is currently regarded as a novel drug for treatment of acute heart failure. However, whether therapeutic effects of serelaxin are achieved by inhibiting cardiac fibrosis remains unclear. In this study, we investigate effects of serelaxin on inhibiting cardiac fibrosis. Cardiac fibroblasts (CFs) were isolated from the hearts of adult rats. Effects of serelaxin on differentiation of CFs towards myofibroblasts (MFs) and their fibrotic behaviors after induction with TGF-β1 were examined. Synthesis and degradation of collagens, secretion of IL-10, and expression of ALK-5 and p-Smad2/3 of TGF-β1-induced cells were assessed after treatment with serelaxin. Serelaxin inhibited differentiation of TGF-β1-induced CFs towards MFs, and reduced proliferation and migration of the induced cells. Moreover, serelaxin down-regulated expression of collagen I/III and TIMP-2, and up-regulated expression of MMP-2 and MMP-9 in the cells. After treatment with serelaxin, activity of MMP-2 and MMP-9 and secretion of IL-10 increased, expression of ALK-5 and the level of Smad2/3 phosphorylation was reduced significantly. These results suggest that serelaxin can inhibit differentiation of TGF-β1-induced CFs towards MFs, reduce production of collagens by suppressing ALK-5/Smad2/3 signaling pathway, and enhance extracellular matrix degradation by increasing MMP-2/TIMP-2 ratio and IL-10 secretion. Serelaxin may be a potential therapeutic drug for inhibiting cardiac fibrosis.

Blockade of extracellular heat shock protein 90α by 1G6-D7 attenuates pulmonary fibrosis through inhibiting ERK signaling

Pulmonary fibrosis is characterized by lung fibroblast activation and ECM deposition and has a poor prognosis. Heat shock protein 90 (Hsp90) participates in organ fibrosis, and extracellular Hsp90α (eHsp90α) promotes fibroblast activation and migration. This study aimed to investigate whether a selective anti-Hsp90α monoclonal antibody, 1G6-D7, could attenuate lung fibrosis and whether 1G6-D7 presents a protective effect by inactivating the profibrotic pathway. Our results showed that eHsp90α was increased in mice with BLM-induced pulmonary fibrosis and that 1G6-D7 attenuated inflammation and collagen deposition in the lung. TGF-β1 induced eHsp90α secretion, concomitantly promoting HFL-1 activation and ECM synthesis. 1G6-D7-mediated inhibition of eHsp90α significantly blocked these effects, meanwhile inhibiting downstream profibrotic pathways such as ERK, Akt, and P38. Human recombinant (hr)Hsp90α mimicked the effects of TGF-β1, by activating profibrotic pathways and by upregulating LRP-1. Moreover, ERK inhibition effectively blocked the effect of (hr)Hsp90α. In conclusion, 1G6-D7 significantly protects against BLM-induced pulmonary fibrosis by ameliorating fibroblast activation and ECM production, which may be through blocking ERK signaling. Our results suggest a safer molecular therapy, 1G6-D7, in pulmonary fibrosis.