Enhanced Levels of Fractalkine and HSP60 in Cerebrospinal Fluid of Sporadic Amyotrophic Lateral Sclerosis Patients

Amyotrophic Lateral Sclerosis (ALS) is a multifactorial neurodegenerative disorder with a significant contribution of non-cell autonomous mechanisms to motor neuronal degeneration. Amongst a plethora of molecules, Fractalkine (C-X3-C motif chemokine ligand 1), and Heat Shock Protein 60 (HSP60), are key modulators of microglial activation. The contribution of these molecules in Sporadic ALS (SALS) remains unexplored. To investigate this, fractalkine levels were estimated in Cerebrospinal fluid (CSF) of SALS patients (ALS-CSF; n = 44) by Enzyme-linked Immunosorbent Assay (ELISA) and correlated with clinical parameters including disease severity and duration. CSF HSP60 levels were estimated by Western blotting (ALS-CSF; n = 19). Also, CSF levels of Chitotriosidase-1 (CHIT-1), a microglia-specific neuroinflammatory molecule, were measured and its association, if any, with fractalkine and HSP60 was investigated. Both Fractalkine and HSP60 levels were significantly elevated in ALS-CSF. Similar to our earlier observation, CHIT-1 levels were also upregulated. Fractalkine showed a moderate negative correlation with the ALS-Functional Rating Scale (ALSFRS) score indicating its significant rise in mild cases which plateaued in cases with high disease severity. However, no obvious correlation was found between fractalkine, HSP60, and CHIT-1. Our study hints that high fractalkine levels in mild cases might be conferring neuroprotection by combating microglial activation and highlights its importance as a novel therapeutic target for SALS. On the other hand, significantly enhanced levels of HSP60, a pro-inflammatory molecule, hint towards its role in accentuating microgliosis, although, it doesn't act synergistically with CHIT-1. Our study suggests that fractalkine and HSP60 act independently of CHIT-1 to suppress and accentuate neuroinflammation, respectively.

Phthalate drives splenic inflammatory response via activating HSP60/TLR4/NLRP3 signaling axis-dependent pyroptosis

As the most produced phthalate, di-(2-ethylhexyl) phthalate (DEHP) is a widely environmental pollutant primarily used as a plasticizer, which cause the harmful effects on human health. However, the impact of DEHP on spleen and its underlying mechanisms are still unclear. Pyroptosis is a novel form of cell death induced by activating NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasomes and implicated in pathogenesis of numerous inflammatory diseases. The current study aimed to explore the impact of DEHP on immune inflammatory response in mouse spleen. In this study, the male ICR mice were treated with DEHP (200 mg/kg) for 28 days. Here, DEHP exposure caused abnormal pathohistological and ultrastructural changes, accompanied by inflammatory cells infiltration in mouse spleen. DEHP exposure arouse heat shock response that involves increase of heat shock proteins 60 (HSP60) expression. DEHP also elevated the expressions of toll-like receptor 4 (TLR4) and myeloid differentiation protein 88 (MyD88) proteins, as well as the activation of NF-κB pathway. Moreover, DEHP promoted NLRP3 inflammasome activation and triggered NLRP3 inflammasome-induced pyroptosis. Mechanistically, DEHP drives splenic inflammatory response via activating HSP60/TLR4/NLRP3 signaling axis-dependent pyroptosis. Our findings reveal that targeting HSP60-mediated TLR4/NLRP3 signaling axis may be a promising strategy for inflammatory diseases treatment.

Heat Shock Proteins (HSPs) and Cardiovascular Complications of Obesity: Searching for Potential Biomarkers

Heat shock proteins (HSPs), a family of proteins that support cellular proteostasis and perform a protective function under various stress conditions, such as high temperature, intoxication, inflammation, or tissue hypoxia, constitute a promising group of possible biochemical markers for obesity and cardiovascular diseases. HSP27 is involved in essential cellular processes occurring in conditions of obesity and its cardiometabolic complications; it has protective properties, and its secretion may indicate a cellular response to stress. HSP40 plays a controversial role in the pathogenesis of obesity. HSP60 is involved in various pathological processes of the cardiovascular, immune, excretory, and nervous systems and is associated with obesity and concomitant diseases. The hypersecretion of HSP60 is associated with poor prognosis; hence, this protein may become a target for further research on obesity and its cardiovascular complications. According to most studies, intracellular HSP70 is an obesity-promoting factor, whereas extracellular HSP70 exhibited inconsistent dynamics across different patient groups and diagnoses. HSPs are involved in the pathogenesis of cardiovascular pathology. However, in the context of cardiovascular and metabolic pathology, these proteins require further investigation.

The proteomics analysis of extracellular vesicles revealed the possible function of heat shock protein 60 in Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric diseases, including gastritis and gastric cancer. Heat shock protein 60 (HSP60) is a chaperone protein involved in various cellular processes and has been implicated in the immune response to bacterial infections. Extracellular vesicles (EVs) containing various protein components play important roles in cell communication. In the present study, a systematic proteomic analysis of EVs obtained from H. pylori infected cells was performed and the EV-derived HSP60 function was studied.

METHODS

EVs were evaluated by nanoparticle tracking analysis, transmission electron microscopy and western blotting. The recognized protein components were quantified by label-free proteomics and subjected to bioinformatics assays. The expression of HSP60 in EVs, host cells and gastric cancers infected by H. pylori was determined by western blotting and immunohistochemical, respectively. In addition, the apoptotic regulation mechanisms of HSP60 in H. pylori infection were analyzed by western blotting and flow cytometry.

RESULTS

A total of 120 important differential proteins were identified in the EVs from H. pylori-infected cells and subjected to Gene Ontology analysis. Among them, CD63, HSP-70 and TSG101 were verified via western blotting. Moreover, HSP60 expression was significantly increased in the EVs from H. pylori-infected GES-1 cells. H. pylori infection promoted an abnormal increase in HSP60 expression in GES-1 cells, AGS cells, gastric mucosa and gastric cancer. In addition, knockdown of HSP60 suppressed the apoptosis of infected cells and the expression of Bcl2, and promoted the upregulation of Bax.

CONCLUSION

This study provides a comprehensive proteomic profile of EVs from H. pylori-infected cells, shedding light on the potential role of HSP60 in H. pylori infection. The findings underscore the significance of EV-derived HSP60 in the pathophysiology of H. pylori-associated diseases.

Mifepristone inhibits hepatoma growth by enhancing the GR-HSP60-survivin interaction to facilitate survivin degradation

Silencing of heat shock protein 60 (HSP60) suppresses the growth of hepatocellular carcinoma (HCC). Mifepristone inhibits HSP60 mRNA expression in Chlamydophila-infected epithelial cells. The aim of this study was to determine whether mifepristone could inhibit the growth of HCC cells by affecting the functions of HSP60. The effect of mifepristone on cell viability was examined by flow cytometry and a cell proliferation assay. Protein-protein interactions were examined using the immunoprecipitation assay. The anti-tumor effect of mifepristone was evaluated using a xenograft model. Our results indicated that mifepristone induces cell cycle arrest at the G1 phase and early-stage apoptosis in HCC cells. Instead of reducing the total amount of HSP60, mifepristone induced the release of mitochondrial HSP60 into the cytosol by causing a loss of ΔΨm, thereby enhancing glucocorticoid receptor (GR)-HSP60-survivin complex formation as well as survivin degradation. Animal models have confirmed the growth inhibitory effects of mifepristone on HCC, including changes in the abundance of HSP60 in mitochondria and cytosol, decreased survivin and Ki-67-positive cells, as well as increased cell apoptosis. In conclusion, the inhibition of HCC growth by mifepristone may be achieved by altering the subcellular distribution of HSP60 to enhance the formation of cytosolic GR-HSP60-survivin complexes in the cells, leading to the degradation of survivin.

High expression of HSP60 and survivin predicts poor prognosis for oral squamous cell carcinoma patients

BACKGROUND

HSP60 is a heat shock proteins (HSPs) family member and help mitochondrial protein to fold correctly. Survivin is one of the inhibitors of apoptosis protein family member, which plays a significant part in cancer progression. They were capable of forming HSP60-survivin complexes and involved in the development of various tumors.

METHODS

The Cancer Genome Atlas (TCGA) database demonstrated that HSP60 and survivin and their correlation on mRNA expression level with OSCC patients. Besides, expression of HSP60 and survivin proteins was studied utilizing immunohistochemistry in tissue microarrays (TMA) in OSCC and in adjacent non-cancerous squamous epithelium (Non-CCSE) tissues.

RESULTS

Significantly increased levels of HSP60 and survivin in most cancers compared to normal tissue by pan-cancer analysis. HSP60 and survivin proved a significantly increased expression in OSCC samples compared to Non-CCSE both on mRNA and protein (both P < 0.05). Additionally, elevated HSP60 displayed a positive correlation with survivin in terms of mRNA and protein expression levels (all P < 0.001). Patients with OSCC who had advanced clinical stage or lymph node metastasis (LNM) showed higher HSP60 expression (P = 0.004, P = 0.006, respectively). Higher levels of the proteins HSP60 and survivin were significantly inversely correlated relationship with OSCC patients' overall survival rates in multivariate survival analysis (P = 0.018, P = 0.040). From the above results, overexpression of HSP60 and survivin protein may serve as independent biomarkers predicting poor prognosis in OSCC.

CONCLUSIONS

Elevated HSP60 and survivin might be served as novel poor prognosis biomarkers for surgically resected OSCC patients.

Lambda-cyhalothrin enhances inflammation in nigrostriatal region in rats: Regulatory role of NF-κβ and JAK-STAT signaling

The risk to develop neurobehavioural abnormalities in humans on exposure to lambda-cyhalothrin (LCT) - a type II synthetic pyrethroid has enhanced significantly due to its extensive uses in agriculture, homes, veterinary practices and public health programs. Earlier, we found that the brain dopaminergic system is vulnerable to LCT and affects motor functions in rats. In continuation to this, the present study is focused to unravel the role of neuroinflammation in LCT-induced neurotoxicity in substantia nigra and corpus striatum in rats. Increase in the mRNA expression of proinflammatory cytokines (TNF- α, IL-1β, IL-6) and iNOS whereas decrease in anti-inflammatory cytokine (IL-10) was distinct both in substantia nigra and corpus striatum of rats treated with LCT (0.5, 1.0, 3.0 mg/kg body weight, p.o, for 45 days) as compared to control rats. Further, LCT-treated rats exhibited increased levels of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (Iba-1), the glial marker proteins both in substantia nigra and corpus striatum as compared to controls. Exposure of rats to LCT also caused alterations in the levels of heat shock protein 60 (HSP60) and mRNA expression of toll-like receptors (TLR2 and TLR4) in the substantia nigra and corpus striatum. An increase in the phosphorylation of key proteins involved in NF-kβ (P65, Iκβ, IKKα, IKKβ) and JAK/STAT (STAT1, STAT3) signaling and alteration in the protein levels of JAK1 and JAK2 was prominent in LCT-treated rats. Histological studies revealed damage of dopaminergic neurons and reactive gliosis as evidenced by the presence of darkly stained pyknotic neurons and decrease in Nissl substance and an increase in infiltration of immune cells both in substantia nigra and corpus striatum of LCT-treated rats. Presence of reactive microglia and astrocytes in LCT-treated rats was also distinct in ultrastructural studies. The results exhibit that LCT may damage dopaminergic neurons in the substantia nigra and corpus striatum by inducing inflammation as a result of stimulation of neuroglial cells involving activation of NF-κβ and JAK/STAT signaling.

Knockdown of heat shock protein family D member 1 (HSPD1) promotes proliferation and migration of ovarian cancer cells via disrupting the stability of mitochondrial 3-oxoacyl-ACP synthase (OXSM)

BACKGROUND

Heat shock protein 60 (HSP60) is essential for the folding and assembly of newly imported proteins to the mitochondria. HSP60 is overexpressed in most types of cancer, but its association with ovarian cancer is still in dispute. SKOV3 and OVCAR3 were used as experimental models after comparing the expression level of mitochondrial HSP60 in a normal human ovarian epithelial cell line and four ovarian cancer cell lines.

RESULTS

Low HSPD1 (Heat Shock Protein Family D (HSP60) Member 1) expression was associated with unfavorable prognosis in ovarian cancer patients. Knockdown of HSPD1 significantly promoted the proliferation and migration of ovarian cancer cells. The differentially expressed proteins after HSPD1 knockdown were enriched in the lipoic acid (LA) biosynthesis and metabolism pathway, in which mitochondrial 3-oxoacyl-ACP synthase (OXSM) was the most downregulated protein and responsible for lipoic acid synthesis. HSP60 interacted with OXSM and overexpression of OXSM or LA treatment could reverse proliferation promotion mediated by HSPD1 knockdown.

CONCLUSIONS

HSP60 interacted with OXSM and maintained its stability. Knockdown of HSPD1 could promote the proliferation and migration of SKOV3 and OVCAR3 via lowering the protein level of OXSM and LA synthesis.

Cathelicidins Target HSP60 To Restrict CVB3 Transmission via Disrupting the Exosome and Reducing Cardiomyocyte Apoptosis

Cathelicidin antimicrobial peptides (mouse, CRAMP; human, LL-37) have broad-spectrum antiviral activities against enveloped viruses, but their mechanisms of action against nonenveloped viruses remain to be elucidated. Coxsackievirus B3 (CVB3), a member of nonenveloped virus belonging to the Enterovirus genus of Picornaviridae, is an important pathogen of viral myocarditis and dilated cardiomyopathy. Here, we observed that cardiac CRAMP expression was significantly upregulated in mice after CVB3 infection. The administration of CRAMP or LL-37 markedly suppressed CVB3 infection in mice, and CRAMP deficiency increased the susceptibility of mice to CVB3. CRAMP and LL-37 inhibited CVB3 replication in primary cardiomyocytes. However, they did not inactivate CVB3 particles and did not regulate the response of cardiomyocytes against CVB3 infection. Intriguingly, they inhibited CVB3 transmission through the exosome, but not virus receptor. In detail, CRAMP and LL-37 directly induced the lysis of exosomes by interfering with exosomal heat shock protein 60 (HSP60) and then blocked the diffusion of exosomes to recipient cells and inhibited the establishment of productive infection by exosomes. In addition, the interaction of CRAMP and LL-37 with HSP60 simultaneously inhibited HSP60-induced apoptosis in cardiomyocytes and reduced HSP60-enhanced CVB3 replication. Our findings reveal a novel mechanism of cathelicidins against viral infection and provide a new therapeutic strategy for CVB3-induced viral myocarditis. IMPORTANCE The relative mechanisms that cathelicidin antimicrobial peptides use to influence nonenveloped virus infection are unclear. We show here that cathelicidin antimicrobial peptides (CRAMP and LL-37) directly target exosomal HSP60 to destroy exosomes, which in turn block the diffusion of exosomes to recipient cardiomyocytes and reduced HSP60-induced apoptosis, thus restricting coxsackievirus B3 infection. Our results provide new insights into the mechanisms cathelicidin antimicrobial peptides use against viral infection.

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.

Role of the heat shock protein family in chlorpromazine-induced cardiotoxicity

Chlorpromazine (CPZ), a first-generation antipsychotic, is widely used in treating schizophrenia and other psychiatric disorders. However, CPZ is also associated with an increased likelihood of sudden cardiac death, and the underlying mechanisms remain unclear. In our study, we aimed to determine the CPZ-induced changes in some members of the heat shock protein family in rat hearts and further explore the possible mechanisms of CPZ-induced cardiotoxicity. Twenty-four Sprague Dawley rats were randomly divided into three groups (n = 8 per group): control, low dose (33.216 mg/kg) and high dose (94.211 mg/kg). CPZ administration induced hypothermia in rats. Pathological changes, including ischaemia and hypoxia, were observed in rat hearts. Furthermore, the serum levels of cardiac Troponin T (c-TN-T) and brain natriuretic peptide (BNP) were elevated in the CPZ-exposed groups. Meanwhile, the protein and gene expression of HSP70, HSP60, HSP27 and HSP10 significantly differed between the CPZ-exposed and control groups. We conclude that acute CPZ exposure could lead to myocardial injury in rats, in which HSPs might play a crucial role. Further investigations are required to elucidate the underlying mechanisms.

Heat shock protein 60 in parasitic helminths: A role in immune responses and therapeutic applications

Heat shock protein 60 (HSP60) is an unique member of the heat shock protein family, being involved in parasite infections. To cope with harsh environments where parasites live, HSP60s are indispensable and involved in a variety of biological processes. HSP60s have relative low similarity among parasites, but their ATPase /Mg²⁺ active sites are highly conserved. The interactions of HSP60s with signaling pathway regulators in immune cells suggest a crucial role in immune responses, rendering them a potential therapeutic target. This paper reviews the current understandings of HSP60s in parasitic helminths in aspects of molecular characteristics, immunoregulatory responses and HSP60-based therapeutics.

Extracellular vesicle-encapsulated CC16 as novel nanotherapeutics for treatment of acute lung injury

Acute lung injury (ALI) is still associated with high mortality. Growing evidence suggests that Club Cell Protein 16 (CC16) plays a protective role against ALI. However, the doses of recombinant CC16 (rCC16) used in preclinical studies are supraphysiological for clinical applications. Extracellular vesicles (EVs) are nanovesicles endogenously generated by mammalian cells. Our study demonstrated that CC16 is released via small EVs and EV-encapsulated CC16 (sEV-CC16) and has anti-inflammatory activities, which protect mice from lipopolysaccharide (LPS) or bacteria-induced ALI. Additionally, sEV-CC16 can activate the DNA damage repair signaling pathways. Consistent with this activity, we observed more severe DNA damage in lungs from Cc16 knockout (KO) than wild-type (WT) mice. Mechanistically, we elucidated that CC16 suppresses nuclear factor κB (NF-κB) signaling activation by binding to heat shock protein 60 (HSP60). We concluded that sEV-CC16 could be a potential therapeutic agent for ALI by inhibiting the inflammatory and DNA damage responses by reducing NF-κB signaling.

A peptide derived from HSP60 reduces proinflammatory cytokines and soluble mediators: a therapeutic approach to inflammation

Cytokines are secretion proteins that mediate and regulate immunity and inflammation. They are crucial in the progress of acute inflammatory diseases and autoimmunity. In fact, the inhibition of proinflammatory cytokines has been widely tested in the treatment of rheumatoid arthritis (RA). Some of these inhibitors have been used in the treatment of COVID-19 patients to improve survival rates. However, controlling the extent of inflammation with cytokine inhibitors is still a challenge because these molecules are redundant and pleiotropic. Here we review a novel therapeutic approach based on the use of the HSP60-derived Altered Peptide Ligand (APL) designed for RA and repositioned for the treatment of COVID-19 patients with hyperinflammation. HSP60 is a molecular chaperone found in all cells. It is involved in a wide diversity of cellular events including protein folding and trafficking. HSP60 concentration increases during cellular stress, for example inflammation. This protein has a dual role in immunity. Some HSP60-derived soluble epitopes induce inflammation, while others are immunoregulatory. Our HSP60-derived APL decreases the concentration of cytokines and induces the increase of FOXP3+ regulatory T cells (Treg) in various experimental systems. Furthermore, it decreases several cytokines and soluble mediators that are raised in RA, as well as decreases the excessive inflammatory response induced by SARS-CoV-2. This approach can be extended to other inflammatory diseases.

EPLIN, a Putative Tumour Suppressor in Colorectal Cancer, Implications in Drug Resistance

Colorectal cancer is a serious threat to human health. Poor prognosis and frequently reported drug resistance urges research into novel biomarkers and mechanisms to aid in the understanding of the development and progression of colorectal cancer and to optimise therapeutic strategies. In the current study, we investigated the roles of a putative tumour suppressor, EPLIN, in colorectal cancer. Our clinical colorectal cancer cohort and online databases revealed a downregulation of EPLIN in colorectal cancer tissues compared with normal tissues. The reduced expression of EPLIN was associated with poor clinical outcomes of patients. In vitro cellular function assays showed that EPLIN elicited an inhibitory effect on cellular growth, adhesion, migration and invasion. Utilising a protein microarray on protein samples from normal and tumour patient tissues suggested HSP60, Her2 and other signalling events were novel potential interacting partners of EPLIN. It was further revealed that EPLIN and HSP60 were negative regulators of Her2 in colorectal cancer cells. The clinical cohort also demonstrated that expression of HSP60 and Her2 affected clinical outcomes, but most interestingly the combination of EPLIN, HSP60 and Her2 was able to identify patients with the most unfavourable clinical outcome by independently predicting patient overall survival and disease free survival. Furthermore, EPLIN and HSP60 exhibited potential to regulate cellular response to chemotherapeutic and EGFR/Her2 targeted therapeutic agents. In conclusion, EPLIN is an important prognostic factor for patients with colon cancer and reduced EPLIN in CRC contributes to aggressive traits of CRC cells and their responses to chemotherapeutic drugs. Collectively, EPLIN is a pivotal factor for the development and progression of colorectal cancer and has important clinical and therapeutic values in this cancer type.

Bis-aryl-α,β-unsaturated ketone (ABK) chaperonin inhibitors exhibit selective cytotoxicity to colorectal cancer cells that correlates with levels of aberrant HSP60 in the cytosol

While many studies have established the importance of protein homeostasis in tumor progression, little effort has been made to examine the therapeutic potential of targeting the HSP60 chaperonin system. In healthy cells, HSP60 is localized to the mitochondrial matrix; however, emerging evidence indicates HSP60 can be over-expressed and mis-localized to the cytosol of cancer cells, which is hypothesized to promote tumor cell survival and proliferation. This opens a potential avenue to selectively target the aberrant HSP60 in the cytosol as a chemotherapeutic strategy. In the present work, we examined a series of bis-aryl-α,β-unsaturated ketone (ABK) HSP60 inhibitors for their ability to selectively target cancerous vs non-cancerous colon and intestine cells. We found that lead analogs inhibited migration and clonogenicity of cancer cells, with cytotoxicity correlating with the level of aberrant HSP60 in the cytosol.

6-Shogaol Exhibits a Promoting Effect with Tax via Binding HSP60 in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) is a prevalent malignant tumor with high morbidity and mortality rates worldwide. Although surgical resection, adjuvant radiotherapy/chemotherapy, and targeted molecular therapy are the cornerstones of NSCLC treatment, NSCLC is associated with high recurrence rates and drug resistance. This study analyzed the potential targets and pathways of 6-Shogaol (6-SH) in NSCLC, showing that 6-SH binds to heat-shock 60 kDa protein (HSP60) in A549 cells, induces cell apoptosis, and arrests the cell cycle possibly by disrupting the mitochondrial function. HSP60 was identified as the target of 6-SH and 6-SH-induced HSP60 degradation which was mediated by the proteasome. The binding of 6-SH with HSP60 altered its stability, inhibited the ERK, Stat3, PI3K, Akt, and mTOR signaling pathways, and Tax acted synergistically with 6-SH, indicating that 6-SH could be developed as a potential therapeutic agent for an NSCLC treatment.

Impaired Heat Shock Protein Expression in Activated T Cells in B-Cell Lymphoma

Heat shock proteins (HSPs) are molecular chaperones that act in a variety of cellular processes, ensuring protein homeostasis and integrity. HSPs play critical roles in the modulation of various immune cells. However, the role of HSPs in T cell activation is largely unknown. We show that HSPs are upregulated following CD3/CD28 stimulation, suggesting that HSP expression might be regulated via TCR. We found that B-cell lymphoma (BCL) patients have dysregulated expression of intracellular and extracellular HSPs, immune checkpoints PD-1, CTLA-4, and STAT3 in CD3/CD28-activated T cells. Consistent with previous findings, we show that HSP90 inhibition downregulated CD4 and CD8 surface markers in healthy controls and BCL patients. HSP90 inhibition alone or in combination with PD-1 or CTLA-4 inhibitors differentially affected CD4+ and CD8+ T cell degranulation responses when stimulated with allogeneic DCs or CD3/CD28 in BCL patients. Additionally, we showed that HSP90 inhibition does not significantly affect intracellular PD-1 and CTLA-4 expression in CD3/CD28-activated T cells. These findings may provide the basis for the discovery of novel immunological targets for the treatment of cancer patients and improve our understanding of HSP functions in immune cells.

Thermal stress and mutation accumulation increase heat shock protein expression in Daphnia

Understanding the short- and long-term consequences of climate change is a major challenge in biology. For aquatic organisms, temperature changes and drought can lead to thermal stress and habitat loss, both of which can ultimately lead to higher mutation rates. Here, we examine the effect of high temperature and mutation accumulation on gene expression at two loci from the heat shock protein (HSP) gene family, HSP60 and HSP90. HSPs have been posited to serve as 'mutational capacitors' given their role as molecular chaperones involved in protein folding and degradation, thus buffering against a wide range of cellular stress and destabilization. We assayed changes in HSP expression across 5 genotypes of Daphnia magna, a sentinel species in ecology and environmental biology, with and without acute exposure to thermal stress and accumulated mutations. Across genotypes, HSP expression increased ~ 6× in response to heat and ~ 4× with mutation accumulation, individually. Both factors simultaneously (lineages with high mutation loads exposed to high heat) increased gene expression ~ 23×-much more than that predicted by an additive model. Our results corroborate suggestions that HSPs can buffer against not only the effects of heat, but also mutations-a combination of factors both likely to increase in a warming world.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10682-022-10209-1.

Tumor cell-released LC3-positive EVs promote lung metastasis of breast cancer through enhancing premetastatic niche formation

Most breast cancer–related deaths are caused by metastasis in vital organs including the lungs. Development of supportive metastatic microenvironments, referred to as premetastatic niches (PMNs), in certain distant organs before arrival of metastatic cells, is critical in metastasis. However, the mechanisms of PMN formation are not fully clear. Here, we demonstrated that chemoattractant C–C motif chemokine ligand 2 (CCL2) could be stimulated by heat shock protein 60 (HSP60) on the surface of murine 4 T1 breast cancer cell–released LC3⁺ extracellular vesicles (LC3⁺ EVs) via the TLR2‐MyD88‐NF‐κB signal cascade in lung fibroblasts, which subsequently promoted lung PMN formation through recruiting monocytes and suppressing T cell function. Consistently, reduction of LC3⁺ EV release or HSP60 level or neutralization of CCL2 markedly attenuated PMN formation and lung metastasis. Furthermore, the number of circulating LC3⁺ EVs and HSP60 level on LC3⁺ EVs in the plasma of breast cancer patients were positively correlated with disease progression and lung metastasis, which might have potential value as biomarkers of lung metastasis in breast cancer patients (AUC = 0.898, 0.694, respectively). These findings illuminate a novel mechanism of PMN formation and might provide therapeutic targets for anti‐metastasis therapy for patients with breast cancer.

Djhsp60 Is Required for Planarian Regeneration and Homeostasis

HSP60, a well-known mitochondrial chaperone, is essential for mitochondrial homeostasis. HSP60 deficiency causes dysfunction of the mitochondria and is lethal to animal survival. Here, we used freshwater planarian as a model system to investigate and uncover the roles of HSP60 in tissue regeneration and homeostasis. HSP60 protein is present in all types of cells in planarians, but it is relatively rich in stem cells and head neural cells. Knockdown of HSP60 by RNAi causes head regression and the loss of regenerating abilities, which is related to decrease in mitotic cells and inhibition of stem cell-related genes. RNAi-HSP60 disrupts the structure of the mitochondria and inhibits the mitochondrial-related genes, which mainly occur in intestinal tissues. RNAi-HSP60 also damages the integrity of intestinal tissues and downregulates intestine-expressed genes. More interestingly, RNAi-HSP60 upregulates the expression of the cathepsin L-like gene, which may be the reason for head regression and necrotic-like cell death. Taking these points together, we propose a model illustrating the relationship between neoblasts and intestinal cells, and also highlight the essential role of the intestinal system in planarian regeneration and tissue homeostasis.

HSP60 regulates the cigarette smoke-induced activation of TLR4-NF-κB-MyD88 signalling pathway and NLRP3 inflammasome

Chronic obstructive pulmonary disease (COPD) is characterized by increased cellular stress and inflammation. Heat shock protein 60 (HSP60) is a highly conserved stress protein that acts as a cellular "danger" signal for immune reactions. In this study, we investigated the role of HSP60 in COPD and explored the underlying mechanisms. Expression levels of HSP60 in patients with acute exacerbation of COPD (AECOPD), stable COPD, and healthy people were detected by Western blotting and enzyme-linked immunosorbent assay (ELISA). Moreover, the effect and molecular mechanism of HSP60 in COPD were studied in cigarette smoke (CS)-treated C57BL/6 mice and macrophages. The results showed significant upregulation of HSP60 expression in the peripheral blood mononuclear cells (PBMCs) and sera of patients with AECOPD compared to those with stable COPD or healthy people. CS induced the expression of HSP60 in the COPD mouse model, accelerated the activation of toll-like receptor 4 (TLR4) and NLR family pyrin domain containing 3 (NLRP3) signalling pathways, promoted the increase of inflammatory cells in alveolar lavage fluid and serum inflammatory factors, and induced destruction of lung tissue structure. Furthermore, HSP60 knockdown affected TLR4 and MyD88 expression, IκBα degradation, and nuclear localization of NF-κB and NLRP3 inflammasome activity. Our study revealed that CS stimulates the expression of HSP60, activating the TLR4-MyD88-NF-κB signalling pathway and the NLRP3 inflammasome.

Heat Shock Protein 60 Restricts Release of Mitochondrial dsRNA to Suppress Hepatic Inflammation and Ameliorate Non-Alcoholic Fatty Liver Disease in Mice

Non-alcoholic fatty liver disease (NAFLD), the most common cause of chronic liver disease, consists of fat deposited (steatosis) in the liver due to causes besides excessive alcohol use. The folding activity of heat shock protein 60 (HSP60) has been shown to protect mitochondria from proteotoxicity under various types of stress. In this study, we investigated whether HSP60 could ameliorate experimental high-fat diet (HFD)-induced obesity and hepatitis and explored the potential mechanism in mice. The results uncovered that HSP60 gain not only alleviated HFD-induced body weight gain, fat accumulation, and hepatocellular steatosis, but also glucose tolerance and insulin resistance according to intraperitoneal glucose tolerance testing and insulin tolerance testing in HSP60 transgenic (HSP60Tg) compared to wild-type (WT) mice by HFD. Furthermore, overexpression of HSP60 in the HFD group resulted in inhibited release of mitochondrial dsRNA (mt-dsRNA) compared to WT mice. In addition, overexpression of HSP60 also inhibited the activation of toll-like receptor 3 (TLR3), melanoma differentiation-associated gene 5 (MDA5), and phosphorylated-interferon regulatory factor 3 (p-IRF3), as well as inflammatory biomarkers such as mRNA of il-1β and il-6 expression in the liver in response to HFD. The in vitro study also confirmed that the addition of HSP-60 mimics in HepG2 cells led to upregulated expression level of HSP60 and restricted release of mt-dsRNA, as well as downregulated expression levels of TLR3, MDA5, and pIRF3. This study provides novel insight into a hepatoprotective effect, whereby HSP60 inhibits the release of dsRNA to repress the TLR3/MDA5/pIRF3 pathway in the context of NAFLD or hepatic inflammation. Therefore, HSP60 may serve as a possible therapeutic target for improving NAFLD.

Proteomic Analysis of Retinal Tissue in an S100B Autoimmune Glaucoma Model

Glaucoma is a neurodegenerative disease that leads to damage of retinal ganglion cells and the optic nerve. Patients display altered antibody profiles and increased antibody titer, e.g., against S100B. To identify the meaning of these antibodies, animals were immunized with S100B. Retinal ganglion cell loss, optic nerve degeneration, and increased glial cell activity were noted. Here, we aimed to gain more insights into the pathophysiology from a proteomic point of view. Hence, rats were immunized with S100B, while controls received sodium chloride. After 7 and 14 days, retinae were analyzed through mass spectrometry and immunohistology. Using data-independent acquisition-based mass spectrometry, we identified more than 1700 proteins on a high confidence level for both study groups, respectively. Of these 1700, 43 proteins were significantly altered in retinae after 7 days and 67 proteins revealed significant alterations at 14 days. For example, α2-macroglobulin was found significantly increased not only by mass spectrometry analysis, but also with immunohistological staining in S100B retinae at 7 and 14 days. All in all, the identified proteins are often associated with the immune system, such as heat shock protein 60. Once more, these data underline the important role of immunological factors in glaucoma pathogenesis.

Structural Alternation in Heat Shock Proteins of Activated Macrophages

The inflammatory response of macrophages is an orderly and complex process under strict regulation accompanied by drastic changes in morphology and functions. It is predicted that proteins will undergo structural changes during these finely regulated processes. However, changes in structural proteome in macrophages during the inflammatory response remain poorly characterized. In the present study, we applied limited proteolysis coupled mass spectrometry (LiP-MS) to identify proteome-wide structural changes in lipopolysaccharide (LPS)-activated macrophages. We identified 386 structure-specific proteolytic fingerprints from 230 proteins. Using the Gene Ontology (GO) biological process enrichment, we discovered that proteins with altered structures were enriched into protein folding-related terms, in which HSP60 was ranked as the most changed protein. We verified the structural changes in HSP60 by using cellular thermal shift assay (CETSA) and native CETSA. Our results showed that the thermal stability of HSP60 was enhanced in activated macrophages and formed an HSP10-less complex. In conclusion, we demonstrate that in situ structural systems biology is an effective method to characterize proteomic structural changes and reveal that the structures of chaperone proteins vary significantly during macrophage activation.

Evaluation of the Altered Tissue Expression of HSP60 and HSP70 Genes in Oral and Cutaneous Lichen Planus Compared to Normal Healthy Tissues

Background:

Recent highlights have investigated the possible roles of molecular chaperons like heat shock proteins (HSPs) into Lichen Planus (LP)-onset and pathogenesis. This study for the first, determine the expression of both HSP60 and HSP70 genes in cutaneous LP (CLP) and oral LP (OLP) lesions compared to normal healthy cases and between different subtypes of OLP lesions by real-time (RT)-PCR.

Materials and Methods:

Paraffin blocks of LP lesions including 56 OLP and 56 CLP samples were selected from theMashhad University of Medical sciences, Mashhad, Iran. Also 56 biopsy samples of healthy normal participants were selected. The demographic and clinical characteristics were extracted from their medical records. The expression of HSP60 and HPS70 genes were evaluated using the real-time RT-PCR method.

Results:

The comparison of the expression of HSP60 and HSP70 genes among the patients with CLP and OLP showed a significant overexpression of HSP60 and HSP70 genes in both groups compared to the normal participants (P = 0.001). The expression of HSP60 and HSP70 genes was high in both the groups of CLP and OLP patients, but the amount was not significantly different between the two groups. Comparing the two mucosal subgroups of OLP lesions (non-erosive and erosive) showed that the expression of the HSP60 and HSP70 in erosive subtypes of OLP was significantly higher than the non-erosive subtypes of OLP (P = 0.001).

Conclusion:

Regarding the overexpression of HSP60 and HSP70 in the LP lesions compared to healthy biopsies, we conclude that HSP60 and HSP70 could have key roles in the etiopathogenesis of the OLP and CLP lesions. The overexpression of both HSP60 and HSP70 in the erosive OLP group compared to the non-erosive OLP group emphasized the possible roles of HSPs in the pathogenesis and premalignant changes of OLP lesions.

A critical review of 25 years of glomalin research: a better mechanical understanding and robust quantification techniques are required

Arbuscular mycorrhizal fungi (AMF) are important contributors to both plant and soil health. Twenty-five years ago, researchers discovered 'glomalin', a soil component potentially produced by AMF, which was unconventionally extracted from soil and bound by a monoclonal antibody raised against Rhizophagus irregularis spores. 'Glomalin' can resist boiling, strong acids and bases, and protease treatment. Researchers proposed that 'glomalin' is a 60 kDa heat shock protein produced by AMF, while others suggested that it is a mixture of soil organic materials that are not unique to AMF. Despite disagreements on the nature of 'glomalin', it has been consistently associated with a long list of plant and soil health benefits, including soil aggregation, soil carbon storage and enhancing growth under abiotic stress. The benefits attributed to 'glomalin' have caused much excitement in the plant and soil health community; however, the mechanism(s) for these benefits have yet to be established. This review provides insights into the current understanding of the identity of 'glomalin', 'glomalin' quantification, and the associated benefits of 'glomalin'. We invite the community to think more critically about how glomalin-associated benefits are generated. We suggest a series of experiments to test hypotheses regarding the nature of 'glomalin' and associated health benefits.

Heat shock proteins with an emphasis on HSP 60

Heat shock phenomenon is a process by which cells express a set of proteins called heat shock proteins (HSPs) against heat stress. HSPs include several families depending upon the molecular weight of the respective protein. Among the different HSPs, The HSP60 is one of the main components representing the framework of chaperone system. HSP60 plays a myriad number of roles like chaperoning, thermotolerance, apoptosis, cancer, immunology and embryonic development. In this review we discussed briefly the general knowledge and focussed on HSP60 in terms of structure, regulation and function in various physiological and pathological conditions.

Diversity in heat shock protein families: functional implications in virus infection with a comprehensive insight of their role in the HIV-1 life cycle

Heat shock proteins (HSPs) are a group of cellular proteins that are induced during stress conditions such as heat stress, cold shock, UV irradiation and even pathogenic insult. They are classified into families based on molecular size like HSP27, 40, 70 and 90 etc, and many of them act as cellular chaperones that regulate protein folding and determine the fate of mis-folded or unfolded proteins. Studies have also shown multiple other functions of these proteins such as in cell signalling, transcription and immune response. Deregulation of these proteins leads to devastating consequences, such as cancer, Alzheimer's disease and other life threatening diseases suggesting their potential importance in life processes. HSPs exist in multiple isoforms, and their biochemical and functional characterization still remains a subject of active investigation. In case of viral infections, several HSP isoforms have been documented to play important roles with few showing pro-viral activity whereas others seem to have an anti-viral role. Earlier studies have demonstrated that HSP40 plays a pro-viral role whereas HSP70 inhibits HIV-1 replication; however, clear isoform-specific functional roles remain to be established. A detailed functional characterization of all the HSP isoforms will uncover their role in cellular homeostasis and also may highlight some of them as potential targets for therapeutic strategies against various viral infections. In this review, we have tried to comprehend the details about cellular HSPs and their isoforms, their role in cellular physiology and their isoform-specific functions in case of virus infection with a specific focus on HIV-1 biology.

Heat shock protein 60 is a disease-associated sialoglycoprotein in human non-small cell lung cancer

The diagnostic and therapeutic potential of Maackia amurensis agglutinin (MAA) have been reported in various malignancies. Earlier, we have found that MAA specifically interacted with human non-small cell lung-cancer (NSCLC) cells and induced apoptosis in these cells. The present study was designed to identify M. amurensis leukoagglutinin (MAL-I, one of the components of MAA, having the same carbohydrate specificity as MAA) interacting membrane sialoglycoprotein(s) of two subtypes of human NSCLC cell lines. Nine proteins were identified using two-dimensional (2D)-polyacrylamide gel electrophoresis (PAGE) followed by MAL-I-overlay transblotting and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). Among these proteins, HSP60 was selected for further characterization. The sialoglycoprotein nature of membrane-HSP60 of NSCLC cell lines was confirmed by its reduced reactivity with MAL-I in Western blots in the presence of GM2 and by dual staining of the cell lines with MAL-I and HSP60-antibody. These findings were further substantiated by enzymatic analysis of membrane-HSP60 as well as in-silico evidence regarding this protein. Our observations were validated by immunohistochemical analysis of both subtypes of NSCLC tissue sections. Membrane-HSP60 was found to be involved in the inhibition of MAL-I-induced morphological alteration of NSCLC cells and also in the proliferation and migration of these cells, indicating the probable role of sialylated membrane-HSP60 in this disease.

Codon usage patterns and evolution of HSP60 in birds

Heat shock protein 60 (HSP60) is highly conserved from prokaryotic to eukaryotic organisms, acting as molecular chaperone and other vital biological functions. In spite of increasing knowledge of HSP60, its evolutionary mechanism on functional adaption is still far from completely understood. Moreover, analysis of codon usage bias (CUB) is a powerful tool to understand evolutionary association studies. However, so far, as we know, no scientific work on CUB of HSP60 in birds has been reported. In this study, we provide a comprehensive analysis on the codon usage and molecular evolution of HSP60 across birds. The results indicated that HSP60 had a weak codon usage bias with high ENC values (range from 52.66 to 61), low RSCU, and A/T-ending codons were mostly preferred. Meanwhile, it was considered that mutation, natural selection, and genetic drift combined to shape codon usage patterns with different strength proportions among various birds for HSP60. Then, the LRT tests suggested that different lineages of birds might be under similar selective pressures. Besides, the two positive selection sites (151 and 131) were detected and might undergo radical changes. These findings would contribute to understand function diversity and molecular evolution of HSP60 in birds.

HSP60 in cancer: a promising biomarker for diagnosis and a potentially useful target for treatment

Heat shock proteins (HSPs), most of which are molecular chaperones, are highly conserved proteins produced by cells under physiological stress or pathological conditions. HSP60 (57-69 kDa) can promote or inhibit cell apoptosis through different mechanisms, and its abnormal expression is also related to tumour cell metastasis and drug resistance. In recent years, HSP60 has received increasing attention in the field of cancer research due to its potential as a diagnostic and prognostic biomarker or therapeutic target. However, in different types of cancer, the specific mechanisms of abnormally expressed HSP60 in tumour carcinogenesis and drug resistance are complicated and still require further study. In this article, we comprehensively review the regulative mechanisms of HSP60 on apoptosis, its applications as a cancer diagnostic biomarker and a therapeutic target, evidence of involvement in tumour resistance and the applications of exosomal HSP60 in liquid biopsy. By evaluating the current findings of HSP60 in cancer research, we highlight some core issues that need to be addressed for the use of HSP60 as a diagnostic or prognostic biomarker and therapeutic target in certain types of cancer.

CIGB-258, a peptide derived from human heat-shock protein 60, decreases hyperinflammation in COVID-19 patients

Hyperinflammation distinguishes COVID-19 patients who develop a slight disease or none, from those progressing to severe and critical conditions. CIGB-258 is a therapeutic option for the latter group of patients. This drug is an altered peptide ligand (APL) derived from the cellular stress protein 60 (HSP60). In preclinical models, this peptide developed anti-inflammatory effects and increased regulatory T cell (Treg) activity. Results from a phase I clinical trial with rheumatoid arthritis (RA) patients indicated that CIGB-258 was safe and reduced inflammation. The aim of this study was to examine specific biomarkers associated with hyperinflammation, some cytokines linked to the cytokine storm granzyme B and perforin in a cohort of COVID-19 patients treated with this peptide. All critically ill patients were under invasive mechanical ventilation and received the intravenous administration of 1 or 2 mg of CIGB-258 every 12 h. Seriously ill patients were treated with oxygen therapy receiving 1 mg of CIGB-258 every 12 h and all patients recovered from their severe condition. Biomarker levels associated with hyperinflammation, such as interleukin (IL)-6, IL-10, tumor necrosis factor (TNF-α), granzyme B, and perforin, significantly decreased during treatment. Furthermore, we studied the ability of CIGB-258 to induce Tregs in COVID-19 patients and found that Tregs were induced in all patients studied. Altogether, these results support the therapeutic potential of CIGB-258 for diseases associated with hyperinflammation. Clinical trial registry: RPCEC00000313.

Exploiting the HSP60/10 chaperonin system as a chemotherapeutic target for colorectal cancer

Over the past few decades, an increasing variety of molecular chaperones have been investigated for their role in tumorigenesis and as potential chemotherapeutic targets; however, the 60 kDa Heat Shock Protein (HSP60), along with its HSP10 co-chaperone, have received little attention in this regard. In the present study, we investigated two series of our previously developed inhibitors of the bacterial homolog of HSP60/10, called GroEL/ES, for their selective cytotoxicity to cancerous over non-cancerous colorectal cells. We further developed a third "hybrid" series of analogs to identify new candidates with superior properties than the two parent scaffolds. Using a series of well-established HSP60/10 biochemical screens and cell-viability assays, we identified 24 inhibitors (14%) that exhibited > 3-fold selectivity for targeting colorectal cancer over non-cancerous cells. Notably, cell viability EC₅₀ results correlated with the relative expression of HSP60 in the mitochondria, suggesting a potential for this HSP60-targeting chemotherapeutic strategy as emerging evidence indicates that HSP60 is up-regulated in colorectal cancer tumors. Further examination of five lead candidates indicated their ability to inhibit the clonogenicity and migration of colorectal cancer cells. These promising results are the most thorough analysis and first reported instance of HSP60/10 inhibitors being able to selectively target colorectal cancer cells and highlight the potential of the HSP60/10 chaperonin system as a viable chemotherapeutic target.

GroEL protein of the Leptospira spp. interacts with host proteins and induces cytokines secretion on macrophages

BACKGROUND

Leptospirosis is a zoonotic disease caused by infection with spirochetes from Leptospira genus. It has been classified into at least 17 pathogenic species, with more than 250 serologic variants. This wide distribution may be a result of leptospiral ability to colonize the renal tubules of mammalian hosts, including humans, wildlife, and many domesticated animals. Previous studies showed that the expression of proteins belonging to the microbial heat shock protein (HSP) family is upregulated during infection and also during various stress stimuli. Several proteins of this family are known to have important roles in the infectious processes in other bacteria, but the role of HSPs in Leptospira spp. is poorly understood. In this study, we have evaluated the capacity of the protein GroEL, a member of HSP family, of interacting with host proteins and of stimulating the production of cytokines by macrophages.

RESULTS

The binding experiments demonstrated that the recombinant GroEL protein showed interaction with several host components in a dose-dependent manner. It was also observed that GroEL is a surface protein, and it is secreted extracellularly. Moreover, two cytokines (tumor necrosis factor-α and interleukin-6) were produced when macrophages cells were stimulated with this protein.

CONCLUSIONS

Our findings showed that GroEL protein may contribute to the adhesion of leptospires to host tissues and stimulate the production of proinflammatory cytokines during infection. These features might indicate an important role of GroEL in the pathogen-host interaction in the leptospirosis.

Functional Exploration of Chaperonin (HSP60/10) Family Genes and their Abiotic Stress-induced Expression Patterns in Sorghum bicolor

Background

Sorghum, the C4 dry-land cereal, important for food, fodder, feed and fuel, is a model crop for abiotic stress tolerance with smaller genome size, genetic diversity, and bio-energy traits. The heat shock proteins/chaperonin 60s (HSP60/Cpn60s) assist the plastid proteins, and participate in the folding and aggregation of proteins. However, the functions of HSP60s in abiotic stress tolerance in Sorghum remain unclear.

Methods

Genome-wide screening and in silico characterization of SbHSP60s were carried out along with tissue and stress-specific expression analysis.

Results

A total of 36 HSP60 genes were identified in Sorghum bicolor. They were subdivided into 2 groups, the HSP60 and HSP10 co-chaperonins encoded by 30 and 6 genes, respectively. The genes are distributed on all the chromosomes, chromosome 1 being the hot spot with 9 genes. All the HSP60s were found hydrophilic and highly unstable. The HSP60 genes showed a large number of introns, the majority of them with more than 10. Among the 12 paralogs, only 1 was tandem and the remaining 11 segmental, indicating their role in the expansion of SbHSP60s. Majority of the SbHSP60 genes expressed uniformly in leaf while a moderate expression was observed in the root tissues, with the highest expression displayed by SbHSP60-1. From expression analysis, SbHSP60-3 for drought, SbHSP60-9 for salt, SbHSP60-9 and 24 for heat and SbHSP60-3, 9 and SbHSP10-2 have been found implicated for cold stress tolerance and appeared as the key regulatory genes.

Conclusion

This work paves the way for the utilization of chaperonin family genes for achieving abiotic stress tolerance in plants.

Overexpression of HSP10 correlates with HSP60 and Mcl-1 levels and predicts poor prognosis in non-small cell lung cancer patients

BACKGROUND

HSP60 and its partner HSP10 are members of heat shock proteins (HSPs) family, which help mitochondrial protein to fold correctly. Mcl-1, a member of the Bcl-2 family, plays a crucial role in regulation of cell apoptosis. Aberrant expression of HSP10, HSP60 and Mcl-1 is involved in the development of many tumors.

OBJECTIVE

To examine the association between expression of HSP10, HSP60 and Mcl-1 and clinicopathological features of non-small cell lung cancer (NSCLC).

METHODS

Tissue microarrays including 53 non-cancerous lung tissues (Non-CLT) and 354 surgically resected NSCLC were stained with anti-HSP10, anti-HSP60 and anti-Mcl-1 antibodies respectively by immunohistochemistry.

RESULTS

Higher expression of HSP10, HSP60 and Mcl-1 was found in NSCLC compared with Non-CLT. Both individual and combined HSP10 and HSP60 expression in patients with clinical stage III was higher than that in stage I ∼ II. Expression of HSP10 showed a positive correlation with HSP60 and Mcl-1. Overall survival time of NSCLC patients was remarkably shorter with elevated expression of HSP10, HSP60 and Mcl-1 alone and in combination. Moreover overexpression of HSP10 and Mcl-1 was poor independent prognostic factor for lung adenocarcinoma patients.

CONCLUSIONS

High expression of HSP10, HSP60 and Mcl-1 might act as novel biomarker of poor prognosis for NSCLC patients.

Human skeletal muscle mitochondrial dynamics in relation to oxidative capacity and insulin sensitivity

AIMS/HYPOTHESIS

Mitochondria operate in networks, adapting to external stresses and changes in cellular metabolic demand and are subject to various quality control mechanisms. On the basis of these traits, we here hypothesise that the regulation of mitochondrial networks in skeletal muscle is hampered in humans with compromised oxidative capacity and insulin sensitivity.

METHODS

In a cross-sectional design, we compared four groups of participants (selected from previous studies) ranging in aerobic capacity and insulin sensitivity, i.e. participants with type 2 diabetes (n = 11), obese participants without diabetes (n = 12), lean individuals (n = 10) and endurance-trained athletes (n = 12); basal, overnight fasted muscle biopsies were newly analysed for the current study and we compared the levels of essential mitochondrial dynamics and quality control regulatory proteins in skeletal muscle tissue.

RESULTS

Type 2 diabetes patients and obese participants were older than lean participants and athletes (58.6 ± 4.0 and 56.7 ± 7.2 vs 21.8 ± 2.5 and 25.1 ± 4.3 years, p < 0.001, respectively) and displayed a higher BMI (32.4 ± 3.7 and 31.0 ± 3.7 vs 22.1 ± 1.8 and 21.0 ± 1.5 kg/m², p < 0.001, respectively) than lean individuals and endurance-trained athletes. Fission protein 1 (FIS1) and optic atrophy protein 1 (OPA1) protein content was highest in muscle from athletes and lowest in participants with type 2 diabetes and obesity, respectively (FIS1: 1.86 ± 0.79 vs 0.79 ± 0.51 AU, p = 0.002; and OPA1: 1.55 ± 0.64 vs 0.76 ± 0.52 AU, p = 0.014), which coincided with mitochondrial network fragmentation in individuals with type 2 diabetes, as assessed by confocal microscopy in a subset of type 2 diabetes patients vs endurance-trained athletes (n = 6). Furthermore, lean individuals and athletes displayed a mitonuclear protein balance that was different from obese participants and those with type 2 diabetes. Mitonuclear protein balance also associated with heat shock protein 60 (HSP60) protein levels, which were higher in athletes when compared with participants with obesity (p = 0.048) and type 2 diabetes (p = 0.002), indicative for activation of the mitochondrial unfolded protein response. Finally, OPA1, FIS1 and HSP60 correlated positively with aerobic capacity (r = 0.48, p = 0.0001; r = 0.55, p < 0.001 and r = 0.61, p < 0.0001, respectively) and insulin sensitivity (r = 0.40, p = 0.008; r = 0.44, p = 0.003 and r = 0.48, p = 0.001, respectively).

CONCLUSIONS/INTERPRETATION

Collectively, our data suggest that mitochondrial dynamics and quality control in skeletal muscle are linked to oxidative capacity in humans, which may play a role in the maintenance of muscle insulin sensitivity. CLINICAL TRIAL REGISTRY: numbers NCT00943059, NCT01298375 and NL1888 Graphical abstract.

PKCδ mediates mitochondrial ROS generation and oxidation of HSP60 to relieve RKIP inhibition on MAPK pathway for HCC progression

Both protein kinase C (PKC) and reactive oxygen species (ROS) are well-known signaling messengers cross-talking with each other to activate mitogen-activated protein kinases (MAPKs) for progression of hepatocellular carcinoma (HCC). However, the underlying mechanisms are not well elucidated. Especially, whether mitochondrial ROS (mtROS) is involved and how it triggers MAPK signaling are intriguing. In this study, we found mtROS generation and phosphorylation of MAPKs were mediated by PKCδ in HCCs treated with the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). Heat shock protein 60 (HSP60), one of the chaperones in mitochondria was the major protein oxidized in TPA-treated HCCs. Moreover, depletion of HSP60 or expression of HSP60 cysteine mutant prevented TPA-induced phosphorylation of MAPKs. To delineate how HSP60 mediated MAPK activation, the role of Raf kinase inhibitor protein (RKIP), a negative regulator of MAPK, was investigated. TPA dissociated RKIP from HSP60 in both mitochondria and cytosol, concurrently with translocation of HSP60 and MAPK from mitochondria to cytosol, which was associated with robust phosphorylation of MAPKs in the cytosol. Moreover, TPA induced opposite phenotypical changes of HCCs, G1 cell cycle arrest, and cell migration, which were prevented by mtROS scavengers and depletion of PKCδ and HSP60. Consistently, TPA increased the migration-related genes, hydrogen peroxide inducible clone5, matrix metalloproteinase-1/3, lamininγ2, and suppressed the cell cycle regulator cyclin E1 (CCNE1) via PKCδ/mtROS/HSP60/MAPK-axis. Finally, c-jun and c-fos were required for TPA-induced expression of the migration-related genes and a novel microRNA, miR-6134, was responsible for TPA-induced suppression of CCNE1. In conclusion, PKCδ cross-talked with mtROS to trigger HSP60 oxidation for release of RKIP to activate MAPK, regulating gene expression for migration, and G1 cell cycle arrest in HCC. Targeted therapy aiming at key players like PKCδ, RKIP, and HSP60 is promising for preventing HCC progression.

Functional Differences between E. coli and ESKAPE Pathogen GroES/GroEL

As the GroES/GroEL chaperonin system is the only bacterial chaperone that is essential under all conditions, we have been interested in the development of GroES/GroEL inhibitors as potential antibiotics. Using Escherichia coli GroES/GroEL as a surrogate, we have discovered several classes of GroES/GroEL inhibitors that show potent antibacterial activity against both Gram-positive and Gram-negative bacteria. However, it remains unknown if E. coli GroES/GroEL is functionally identical to other GroES/GroEL chaperonins and hence if our inhibitors will function against other chaperonins. Herein we report our initial efforts to characterize the GroES/GroEL chaperonins from clinically significant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). We used complementation experiments in GroES/GroEL-deficient and -null E. coli strains to report on exogenous ESKAPE chaperone function. In GroES/GroEL-deficient (but not knocked-out) E. coli, we found that only a subset of the ESKAPE GroES/GroEL chaperone systems could complement to produce a viable organism. Surprisingly, GroES/GroEL chaperone systems from two of the ESKAPE pathogens were found to complement in E. coli, but only in the strict absence of either E. coli GroEL (P. aeruginosa) or both E. coli GroES and GroEL (E. faecium). In addition, GroES/GroEL from S. aureus was unable to complement E. coli GroES/GroEL under all conditions. The resulting viable strains, in which E. coli groESL was replaced with ESKAPE groESL, demonstrated similar growth kinetics to wild-type E. coli, but displayed an elongated phenotype (potentially indicating compromised GroEL function) at some temperatures. These results suggest functional differences between GroES/GroEL chaperonins despite high conservation of amino acid identity.IMPORTANCE The GroES/GroEL chaperonin from E. coli has long served as the model system for other chaperonins. This assumption seemed valid because of the high conservation between the chaperonins. It was, therefore, shocking to discover ESKAPE pathogen GroES/GroEL formed mixed-complex chaperonins in the presence of E. coli GroES/GroEL, leading to loss of organism viability in some cases. Complete replacement of E. coli groESL with ESKAPE groESL restored organism viability, but produced an elongated phenotype, suggesting differences in chaperonin function, including client specificity and/or refolding cycle rates. These data offer important mechanistic insight into these remarkable machines, and the new strains developed allow for the synthesis of homogeneous chaperonins for biochemical studies and to further our efforts to develop chaperonin-targeted antibiotics.

Molecular cloning and characterization of HSP60 gene in domestic pigeons (Columba livia) and differential expression patterns under temperature stress

Heat shock protein 60 (HSP60) is a well-recognized multifunctional protein, playing a substantial role in protecting organisms from environmental stress. The domestic pigeon (Columba livia) is a promising model organism, with important economic and ecological value, and its health is susceptible to temperature stress. To explore the molecular characteristics, tissue expression profile, and response to temperature stress for HSP60 of Columba livia (ClHSP60), we firstly cloned and characterized the complete cDNA sequence and investigated its expression profile under optimal conditions and acute temperature stress. The cDNA of ClHSP60 contained 2257 nucleotides, consisting of 12 exons with length ranging from 65 to 590 bp. The open reading frame (ORF) encoded 573 amino acids with calculated molecular weight of 60.97 kDa that contained a number of structurally prominent domains or motifs. Under optimal temperature conditions, levels of ClHSP60 expression differed between all the tested tissues (the highest was noted in liver and the lowest in pectoralis major muscle). Under acute temperature stress, five patterns of change were detected in the tested tissues, suggesting that different tissues in domestic pigeons differentially responded to various temperature stress conditions. Upregulation of ClHSP60 expression was highest in the lung and pectoralis major muscle, reflecting the crucial role of these two tissues in temperature regulation. However, the crop, cerebrum, and heart showed little change or decreased ClHSP60 expression. The results indicate that ClHSP60 may be sensitive to and play pivotal roles in responding to acute temperature stress.

Heat Shock Protein HSP60 in Left Ventricular Cardiomyocytes of Hypertensive Rats with and without Insulin-Dependent Diabetes Mellitus

In cardiomyocytes, high molecular ATP-dependent HSP70 and HSP90 play an important role in protecting the myocardium from abnormal proteins that appear, in particular, due to activation of oxidative stress. Molecular chaperone HSP60 is of particular importance for cardiomyocytes as it is responsible for assembly of mitochondrial matrix proteins. We studied the peculiarities of expression of HSP60 in left ventricular cardiomyocytes in hypertension, insulin-dependent diabetes mellitus, and their combination. The experiment was performed on 38-week-old male Wistar-Kyoto and SHR (spontaneously hypertensive) rats aged 38-57 weeks. Insulin-dependent diabetes mellitus was modeled by a single parenteral administration of 65 mg/kg streptozotocin. Expression of HSP60 in left ventricular cardiomyocytes was evaluated by immunohistochemical methods. It was found that hypertension, diabetes mellitus, and their combination are associated with a significant decrease in the content of HSP60 in left ventricular cardiomyocytes in comparison with the control. This finding can be considered as a pathogenetic mechanism of myocardial damage induced by hypertension and diabetes mellitus.

Has-miR-17 increases the malignancy of gastric lymphoma by HSP60/TNFR2 pathway

The purpose of this study was to investigate the expression and mechanism of miR-17 in gastric lym-phoma. miR-17mimics, miR-17 inhibitors and negative controls were transfected into human gastric lymphoma cell line cyp6d. The proliferation, invasion and apoptosis of cyp6d cells were detected by CCK-8, Transwell and TUNEL methods, respectively. The expression and clinicopathological features of miR-17 in gastric lymphoma were analyzed by real-time quantitative PCR. The target gene of miR-17 was predicted by targetscan 7.2, and the expression of miR-17 related protein was detected by Western blot. The results showed that the expression of miR-17 in gastric lymphoma was significantly higher than that in normal tissues (P < 0.05), which was closely related to lymph node metastasis, tumor size and distant metastasis (P < 0.05). The high expression of miR-17 significantly promoted the proliferation and invasion of cyp6d cells and inhibited apoptosis (P < 0.05). The high expression of miR-17 can regu¬late the expression of HSP60 and TNFR2. It has been found that miR-17 can promote the development of gastric lymphoma by regulating HSP60/TNFR2 pathway, which is a potential molecular target for the diagnosis and treatment of gastric lymphoma.

Abnormal lipid metabolism induced apoptosis of spermatogenic cells by increasing testicular HSP60 protein expression

Long-term consumption of high-fat and high-calorie foods not only causes obesity, but also may cause a decline in sperm quality in men. Rats with abnormal lipid metabolism (high-fat rats) were established by high-fat diet for 24 weeks. HE staining was used to observe the morphological changes of testis in rats, TUNEL and flow cytometer was used to detect the cell apoptosis in rat testis and in vitro. Immunohistochemistry and Western blotting were used to detect the expression of protein. After 24 weeks of high-fat food feeding, the body weight, serum lipids and number of apoptotic spermatogenic cells in the high-fat group rat were significantly higher than those in the control group. In vivo, the expression of HSP60 protein in testis of high-fat rats was positive related to apoptosis of spermatogenic cells, cleaved caspase 3/caspase 3 protein expression and Bax/Bcl2 protein expression in testis of high-fat rats. Proportion of apoptotic spermatogenic cells was increased by up-regulation of HSP60 protein expression in vitro. Long-term consumption of high-fat diets can cause high expression of HSP60 and spermatogenic cells apoptosis in rats, while HSP60 over-expression promotes spermatogenic cell apoptosis and MAPK signal pathway in vitro.

COVID-19 and hypertension: is the HSP60 culprit for the severe course and worse outcome?

The 60-kDa heat shock protein (HSP60) is a chaperone essential for mitochondrial proteostasis ensuring thus sufficient aerobic energy production. In pathological conditions, HSP60 can be translocated from the mitochondria and excreted from the cell. In turn, the extracellular HSP60 has a strong ability to trigger and enhance inflammatory response with marked proinflammatory cytokine induction, which is mainly mediated by Toll-like receptor binding. Previous studies have found increased circulating levels of HSP60 in hypertensive patients, as well as enhanced HSP60 expression and membrane translocation in the hypertrophic myocardium. These observations are of particular interest, since they could provide a possible pathophysiological explanation of the severe course and worse outcome of severe acute respiratory syndrome coronavirus 2 infection in hypertensive patients, repeatedly reported during the recent coronavirus disease 2019 (COVID-19) pandemic and related to hyperinflammatory response and cytokine storm development during the third phase of the disease. In this regard, pharmacological inhibition of HSP60 could attract attention to potentially ameliorate inappropriate inflammatory reaction in severe COVID-19 patients. Among HSP60 antagonizing drugs, mizoribine is the most intriguing, since it is clinically approved and exerts antiviral activity. However, this topic requires to be further scrutinized.

Chemical modification of pro-inflammatory proteins by peroxynitrite increases activation of TLR4 and NF-κB: Implications for the health effects of air pollution and oxidative stress

Environmental pollutants like fine particulate matter can cause adverse health effects through oxidative stress and inflammation. Reactive oxygen and nitrogen species (ROS/RNS) such as peroxynitrite can chemically modify proteins, but the effects of such modifications on the immune system and human health are not well understood. In the course of inflammatory processes, the Toll-like receptor 4 (TLR4) can sense damage-associated molecular patterns (DAMPs). Here, we investigate how the TLR4 response and pro-inflammatory potential of the proteinous DAMPs α-Synuclein (α-Syn), heat shock protein 60 (HSP60), and high-mobility-group box 1 protein (HMGB1), which are relevant in neurodegenerative and cardiovascular diseases, changes upon chemical modification with peroxynitrite.

For the peroxynitrite-modified proteins, we found a strongly enhanced activation of TLR4 and the pro-inflammatory transcription factor NF-κB in stable reporter cell lines as well as increased mRNA expression and secretion of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-8 in human monocytes (THP-1). This enhanced activation of innate immunity via TLR4 is mediated by covalent chemical modifications of the studied DAMPs.

Our results show that proteinous DAMPs modified by peroxynitrite more potently amplify inflammation via TLR4 activation than the native DAMPs, and provide first evidence that such modifications can directly enhance innate immune responses via a defined receptor. These findings suggest that environmental pollutants and related ROS/RNS may play a role in promoting acute and chronic inflammatory disorders by structurally modifying the body's own DAMPs. This may have important consequences for chronic neurodegenerative, cardiovascular or gastrointestinal diseases that are prevalent in modern societies, and calls for action, to improve air quality and climate in the Anthropocene.

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Pollutants and oxidative stress can cause protein nitration and oligomerization.

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Peroxynitrite amplifies inflammatory potential of disease-related proteins in vitro.

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Chemical modification of damage-associated molecular patterns (DAMPs).

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Positive feedback of modified DAMPs via pattern recognition receptor (TLR4).

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Air pollution may promote inflammatory disorders in the Anthropocene.

Mitohormesis Primes Tumor Invasion and Metastasis

Moderate mitochondrial stress can lead to persistent activation of cytoprotective mechanisms - a phenomenon termed mitohormesis. Here, we show that mitohormesis primes a subpopulation of cancer cells to basally upregulate mitochondrial stress responses, such as the mitochondrial unfolded protein response (UPR^mt) providing an adaptive metastatic advantage. In this subpopulation, UPR^mt activation persists in the absence of stress, resulting in reduced oxidative stress indicative of mitohormesis. Mechanistically, we showed that the SIRT3 axis of UPR^mt is necessary for invasion and metastasis. In breast cancer patients, a 7-gene UPR^mt signature demonstrated that UPR^mt-HIGH patients have significantly worse clinical outcomes, including metastasis. Transcriptomic analyses revealed that UPR^mt-HIGH patients have expression profiles characterized by metastatic programs and the cytoprotective outcomes of mitohormesis. While mitohormesis is associated with health and longevity in non-pathological settings, these results indicate that it is perniciously used by cancer cells to promote tumor progression.

Chlorogenic acid alleviates acetaminophen-induced liver injury in mice via regulating Nrf2-mediated HSP60-initiated liver inflammation

Acetaminophen (APAP)-induced acute liver failure is a serious clinic issue. Our previous study showed that chlorogenic acid (CGA) alleviated APAP-induced liver inflammatory injury, but its concrete mechanism is still not clear. This study aims to elucidate the engaged mechanism involved in the CGA-provided alleviation on APAP-induced liver inflammation. CGA reduced the increased hepatic infiltration of immune cells and the elevated serum contents of high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) in mice treated with APAP. CGA decreased the enhanced hepatic mRNA expression of some pro-inflammatory molecules in mice treated with APAP and in RAW264.7 cells stimulated with HMGB1 or HSP60. CGA attenuated liver mitochondrial injury, rescued the decreased lon protease homolog (Lon) protein expression, and reduced mitochondrial HSP60 release in mice treated with APAP. Moreover, the CGA-provided alleviation on APAP-induced liver inflammatory injury was diminished in mice treated with anti-HSP60 antibody. Further results showed that the CGA-provided alleviation on APAP-induced liver inflammation was also diminished in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice. Meanwhile, the CGA-provided reduce on serum HSP60 content and restore of mitochondrial Lon protein expression were all diminished in Nrf2 knock-out mice treated with APAP. In conclusion, our study revealed that CGA alleviated APAP-induced liver inflammatory injury initiated by HSP60 or HMGB1, and Nrf2 was critical for regulating the mitochondrial HSP60 release via rescuing the reduced mitochondrial Lon protein expression.

Heat Shock Protein 60 Antibodies Are Associated With a Risk Factor for Cardiovascular Disease in Bedridden Elderly Patients

Frailty, in elderly people, represents multiple deficiencies in different organs and is characterized by decreased physiological reserves and greater vulnerability to stressors. Bedridden elderly, with cardiovascular disease (CVD), have a worse prognosis than non-bedridden patients. Heat-shock proteins (HSPs) are molecular chaperones that under physiological conditions facilitate the transport, folding and assembly of proteins. Serum HSP 60-kDa concentrations and their antibodies are increased, in response to non-physiological conditions, suggesting the involvement of HSPs and their antibodies in the development of CVD. The aim of this work was to evaluate heat shock protein 60 and anti-HSP60 antibody levels, associated with a risk factor for cardiovascular disease, in bedridden elderly patients. Clinical, analytical and cross-sectional analyses were performed with 57 elderly (>65 years). HSP60 and anti-HSP60 plasma levels were measured by ELISA. Bivariate analysis using a linear regression model adjusted for risk factors used Framingham Score. Among the 57 elderly, with an average age of 69.89 years, 39% are bedridden; 26% with pre-existing cardiovascular disease and 44% are dyslipidemic. The relationship of risk factors in the Framingham Score was positive for the anti-HSP60 antibody (p = 0.042) measurement. Our data show a positive correlation among the elevation of the Framingham score and the profile of anti-HSP60 antibodies. These results suggest a greater immune activation that is associated with cardiovascular risk and bedridden fragility.