Hsp60 accelerates the maturation of pro-caspase-3 by upstream activator proteases during apoptosis

Prognosis value of heat-shock proteins in esophageal and esophagogastric cancer: A systematic review and meta-analysis

BACKGROUND

Heat shock proteins (HSPs) are molecular chaperones that play an important role in cellular protection against stress events and have been reported to be overexpressed in many cancers. The prognostic significance of HSPs and their regulatory factors, such as heat shock factor 1 (HSF1) and CHIP, are poorly understood.

AIM

To investigate the relationship between HSP expression and prognosis in esophageal and esophagogastric cancer.

METHODS

A systematic review was conducted in accordance with PRISMA recommendations (PROSPERO: CRD42022370653), on Embase, PubMed, Cochrane, and LILACS. Cohort, case-control, and cross-sectional studies of patients with esophagus or esophagogastric cancer were included. HSP-positive patients were compared with HSP-negative, and the endpoints analyzed were lymph node metastasis, tumor depth, distant metastasis, and overall survival (OS). HSPs were stratified according to the HSP family, and the summary risk difference (RD) was calculated using a random-effect model.

RESULTS

The final selection comprised 27 studies, including esophageal squamous cell carcinoma (21), esophagogastric adenocarcinoma (5), and mixed neoplasms (1). The pooled sample size was 3465 patients. HSP40 and 60 were associated with a higher 3-year OS [HSP40: RD = 0.22; 95% confidence interval (CI): 0.09-0.35; HSP60: RD = 0.33; 95%CI: 0.17-0.50], while HSF1 was associated with a poor 3-year OS (RD = -0.22; 95%CI: -0.32 to -0.12). The other HSP families were not associated with long-term survival. HSF1 was associated with a higher probability of lymph node metastasis (RD = -0.16; 95%CI: -0.29 to -0.04). HSP40 was associated with a lower probability of lymph node dissemination (RD = 0.18; 95%CI: 0.03-0.33). The expression of other HSP families was not significantly related to tumor depth and lymph node or distant metastasis.

CONCLUSION

The expression levels of certain families of HSP, such as HSP40 and 60 and HSF1, are associated with long-term survival and lymph node dissemination in patients with esophageal and esophagogastric cancer.

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.

Exploring the Role of Hsp60 in Alzheimer's Disease and Type 2 Diabetes: Suggestion for Common Drug Targeting

Heat shock protein 60 (Hsp60) is a member of the chaperonin family of heat shock proteins (HSPs), primarily found in the mitochondrial matrix. As a molecular chaperone, Hsp60 plays an essential role in mediating protein folding and assembly, and together with the co-chaperon Hsp10, it is thought to maintain protein homeostasis. Recently, it has been found to localize in non-canonical, extra-mitochondrial sites such as cell membranes or extracellular fluids, particularly in pathological conditions. Starting from its biological function, this review aims to provide a comprehensive understanding of the potential involvement of Hsp60 in Alzheimer's disease (AD) and Type II Diabetes Mellitus (T2DM), which are known to share impaired key pathways and molecular dysfunctions. Fragmentary data reported in the literature reveal interesting links between the altered expression level or localization of this chaperonin and several disease conditions. The present work offers an overview of the past and more recent knowledge about Hsp60 and its role in the most important cellular processes to shed light on neuronal Hsp60 as a potential common target for both pathologies. The absence of any effective cure for AD patients makes the identification of a new molecular target a promising path by which to move forward in the development of new drugs and/or repositioning of therapies already used for T2DM.

Exploration of Phaeanthine: A Bisbenzylisoquinoline Alkaloid Induces Anticancer Effect in Cervical Cancer Cells Involving Mitochondria-Mediated Apoptosis

Natural-product-based pharmacophores possess considerably more structural diversity, attractive physicochemical features, and relatively less toxicity than synthesized drug entities. In this context, our studies on phaeanthine, a bisbenzylisoquinoline alkaloid isolated from the rhizomes of Cyclea peltata (Lam) Hook.f & Thoms., showed selective cytotoxicity toward cervical cancer cells (HeLa) with an IC₅₀ of 8.11 ± 0.04 μM. Subsequent investigation with in silico molecular docking of phaeanthine displayed preferential binding to the antiapoptotic protein Akt as reflected by a docking score of -5.023. Interestingly, the follow-up in vitro assessment of the compound correlated with mitochondria-mediated apoptosis specifically by downregulating the expression of Akt and p-Akt, including other antiapoptotic proteins MCl-1, IGF-2, and XIAP. In the complementary in vitro assessment, mitochondrial membrane polarization and dynamics of intercellular cytochrome c validated the intrinsic mechanism of the apoptotic phenomenon. To the best of our knowledge, this is the first comprehensive anticancer profiling study of phaeanthine against HeLa cells.

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.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim: Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed. Materials and Methods: Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs). Results: The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs. Conclusion: The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress. Keywords: climate change, external environment, heat shock proteins, heat stress, mRNA, temperature-humidity index.

Expression profiling of heat shock protein genes in whole blood of Romosinuano cattle breed

Background and Aim

Heat shock proteins are highly conserved proteins that work as molecular chaperones expressed in response to thermal stress. This study aimed to determine the expression profile of genes related to the heat stress response in whole blood obtained from the Romosinuano creole breed.

Materials and Methods

Real-time polymerase chain reaction was performed to analyze the transcript of hsp90, hsp70, hsp60, and hsf1 in the whole blood of Romosinuano under different temperature-humidity indices (THIs).

Results

The expression levels of the hsp70 and hsf1 genes at the high-THI level were higher (p = 0.0011 and p = 0.0003, respectively) than those at the low-THI level. In addition, no differences in the expression levels of the hsp60 and hsP90 genes were detected between the two THIs.

Conclusion

The overexpression of hsf1 and hsp70 genes play an important role in protecting cells from damage induced by heat stress.

Chaperonin: Co-chaperonin Interactions

Co-chaperonins function together with chaperonins to mediate ATP-dependent protein folding in a variety of cellular compartments. Chaperonins are evolutionarily conserved and form two distinct classes, namely, group I and group II chaperonins. GroEL and its co-chaperonin GroES form part of group I and are the archetypal members of this family of protein folding machines. The unique mechanism used by GroEL and GroES to drive protein folding is embedded in the complex architecture of double-ringed complexes, forming two central chambers that undergo conformational rearrangements that enable protein folding to occur. GroES forms a lid over the chamber and in doing so dislodges bound substrate into the chamber, thereby allowing non-native proteins to fold in isolation. GroES also modulates allosteric transitions of GroEL. Group II chaperonins are functionally similar to group I chaperonins but differ in structure and do not require a co-chaperonin. A significant number of bacteria and eukaryotes house multiple chaperonin and co-chaperonin proteins, many of which have acquired additional intracellular and extracellular biological functions. In some instances, co-chaperonins display contrasting functions to those of chaperonins. Human HSP60 (HSPD) continues to play a key role in the pathogenesis of many human diseases, in particular autoimmune diseases and cancer. A greater understanding of the fascinating roles of both intracellular and extracellular Hsp10 on cellular processes will accelerate the development of techniques to treat diseases associated with the chaperonin family.

The role of heat shock proteins in metastatic colorectal cancer: A review

Heat shock proteins (HSPs) are a large molecular chaperone family classified by their molecular weights, including HSP27, HSP40, HSP60, HSP70, HSP90, and HSP110. HSPs are likely to have antiapoptotic properties and participate actively in various processes such as tumor cell proliferation, invasion, metastases, and death. In this review, we discuss comprehensively the functions of HSPs associated with the progression of colorectal cancer (CRC) and metastasis and resistance to cancer therapy. Taken together, HSPs have numerous clinical applications as biomarkers for cancer diagnosis and prognosis and potential therapeutic targets for CRC and its related metastases.

Forcing the Antitumor Effects of HSPs Using a Modulated Electric Field

The role of Heat Shock Proteins (HSPs) is a “double-edged sword” with regards to tumors. The location and interactions of HSPs determine their pro- or antitumor activity. The present review includes an overview of the relevant functions of HSPs, which could improve their antitumor activity. Promoting the antitumor processes could assist in the local and systemic management of cancer. We explore the possibility of achieving this by manipulating the electromagnetic interactions within the tumor microenvironment. An appropriate electric field may select and affect the cancer cells using the electric heterogeneity of the tumor tissue. This review describes the method proposed to effect such changes: amplitude-modulated radiofrequency (amRF) applied with a 13.56 MHz carrier frequency. We summarize the preclinical investigations of the amRF on the HSPs in malignant cells. The preclinical studies show the promotion of the expression of HSP70 on the plasma membrane, participating in the immunogenic cell death (ICD) pathway. The sequence of guided molecular changes triggers innate and adaptive immune reactions. The amRF promotes the secretion of HSP70 also in the extracellular matrix. The extracellular HSP70 accompanied by free HMGB1 and membrane-expressed calreticulin (CRT) form damage-associated molecular patterns encouraging the dendritic cells’ maturing for antigen presentation. The process promotes killer T-cells. Clinical results demonstrate the potential of this immune process to trigger a systemic effect. We conclude that the properly applied amRF promotes antitumor HSP activity, and in situ, it could support the tumor-specific immune effects produced locally but acting systemically for disseminated cells and metastatic lesions.

TRAF2/ASK1/JNK Signaling Pathway Is Involved in the Lung Apoptosis of Swine Induced by Cadmium Exposure

Cadmium (Cd), a toxic heavy metal, exists widely in the environment, which can enter organisms through a variety of ways and cause damage to various organs and tissues. However, the mechanism of lung toxicity in swine after Cd exposure is still unclear. To explore the molecular mechanism of swine lung damage caused by Cd exposure, we established the model of Cd exposure, and Cd chloride (20 mg/kg CdCl₂) was added to the diet of swine for continuous exposure for 40 days. TUNEL staining showed that the apoptosis of swine lung increased significantly after Cd exposure. Meanwhile, the results of qRT-PCR showed that Cd induced oxidative stress and inhibited the expression of antioxidant enzymes including CAT, GCLM, GST, SOD, and GSH-px in lung tissue. Cd exposure activated mitochondrial apoptosis pathway via the TRAF2/ASK1/JNK signaling pathway. In brief, we considered that Cd exposure causes oxidative stress in lung and induces lung cell apoptosis through the TRAF2/ASK1/JNK pathway and increases the expression of HSPs to resist the toxicity of Cd. Our research enriches the theoretical basis of Cd toxicity and provides reference for comparative medicine.

Involvement of molecular chaperone in protein-misfolding brain diseases

Protein misfolding causes aggregation and build-up in a variety of brain diseases. There are numeral molecules that are linked with the protein homeostasis mechanism. Molecular chaperones are one of such molecules that are responsible for protection against protein misfolded and aggregation-induced neurotoxicity. Many studies have explored the participation of molecular chaperones in Parkinson's disease, Alzheimer's disease, Amyotrophic lateral sclerosis, and Huntington's diseases. In this review, we highlighted the constructive role of molecular chaperones in neurological diseases characterized by protein misfolding and aggregation and their capability to control aberrant protein interactions at an early stage thus successfully suppressing pathogenic cascades. A comprehensive understanding of the protein misfolding associated with brain diseases and the molecular basis of involvement of chaperone against aggregation-induced cellular stress might lead to the progress of new therapeutic intrusion-related to protein misfolding and aggregation.

Role of heat shock proteins in aging and chronic inflammatory diseases

Advanced age is associated with a decline in response to stress. This contributes to the establishment of chronic inflammation, one of the hallmarks of aging and age-related disease. Heat shock proteins (HSP) are determinants of life span, and their progressive malfunction leads to age-related pathology. To discuss the function of HSP on age-related chronic inflammation and illness. An updated review of literature and discussion of relevant work on the topic of HSP in normal aging and chronic inflammatory pathology was performed. HSP contribute to inflamm-aging. They also play a key role in age-associated pathology linked to chronic inflammation such as autoimmune disorders, neurological disease, cardiovascular disorder, and cancer. HSP may be targeted for control of their effects related to age and chronic inflammation. Research on HSP functions in age-linked chronic inflammatory disorders provides an opportunity to improve health span and delay age-related chronic disorders.

Recent advances in heat shock proteins in cancer diagnosis, prognosis, metabolism and treatment

Heat shock proteins (HSPs) are a group of proteins, also known as molecular chaperones, which participate in protein folding and maturation in response to stresses or high temperature. According to their molecular weights, mammalian HSPs are classified into HSP27, HSP40, HSP60, HSP70, HSP90, and large HSPs. Previous studies have revealed that HSPs play important roles in oncogenesis and malignant progression because they can modulate all six hallmark traits of cancer. Because of this, HSPs have been propelled into the spotlight as biomarkers for cancer diagnosis and prognosis, as well as an exciting anticancer drug target. However, the relationship between the expression level of HSPs and their activity and cancer diagnosis, prognosis, metabolism and treatment is not clear and has not been completely established. Herein, this review summarizes and discusses recent advances and perspectives in major HSPs as biomarkers for cancer diagnosis, as regulators for cancer metabolism or as therapeutic targets for cancer therapy, which may provide new directions to improve the accuracy of cancer diagnosis and develop more effective and safer anticancer therapeutics.

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.

MicroRNA-1 Expression and Function in Hyalomma Anatolicum anatolicum (Acari: Ixodidae) Ticks

MicroRNAs act as mRNA post-transcriptional regulators, playing important roles in cell differentiation, transcriptional regulation, growth, and development. In this study, microRNA expression profiles of Hyalomma anatolicum anatolicum ticks at different developmental stages were detected by high-throughput sequencing and functionally assessed. In total, 2,585,169, 1,252,678, 1,558,217, and 1,155,283 unique reads were obtained from eggs, larvae, nymphs, and adults, respectively, with 42, 46, 45, and 41 conserved microRNAs in these stages, respectively. Using eggs as a control, 48, 43, and 39 microRNAs were upregulated, and 3, 10, and 9 were downregulated in larvae, nymphs, and adults, respectively. MicroRNA-1 (miR-1) was expressed in high abundance throughout Ha. anatolicum development, with an average of nearly one million transcripts, and it is highly conserved among tick species. Quantitative real-time PCR (qPCR) showed that miR-1 expression gradually increased with tick development, reaching the highest level at engorgement. Differential tissue expression was detected, with significantly higher levels in the salivary glands and epidermis than in the midgut. Inhibition assays showed no significant change in body weight or spawning time or amount between experimental and control groups, but there was a significant difference (p < 0.01) in engorgement time. With miR-1 inhibition, ticks displayed obvious deformities during later development. To more fully explain the microRNA mechanism of action, the miR-1 cluster was analyzed according to the target gene; members that jointly act on Hsp60 include miR-5, miR-994, miR-969, and miR-1011. Therefore, microRNAs are critical for normal tick development, and the primary structure of the mature sequence of miR-1 is highly conserved. Nonetheless, different developmental stages and tissues show different expression patterns, with a certain role in prolonging feeding. miR-1, together with other cluster members, regulates mRNA function and may be used as a molecular marker for species origin, evolution analysis, and internal reference gene selection.

Are Heat Shock Proteins an Important Link between Type 2 Diabetes and Alzheimer Disease?

Type 2 diabetes (T2D) and Alzheimer’s disease (AD) are growing in prevalence worldwide. The development of T2D increases the risk of AD disease, while AD patients can show glucose imbalance due to an increased insulin resistance. T2D and AD share similar pathological features and underlying mechanisms, including the deposition of amyloidogenic peptides in pancreatic islets (i.e., islet amyloid polypeptide; IAPP) and brain (β-Amyloid; Aβ). Both IAPP and Aβ can undergo misfolding and aggregation and accumulate in the extracellular space of their respective tissues of origin. As a main response to protein misfolding, there is evidence of the role of heat shock proteins (HSPs) in moderating T2D and AD. HSPs play a pivotal role in cell homeostasis by providing cytoprotection during acute and chronic metabolic stresses. In T2D and AD, intracellular HSP (iHSP) levels are reduced, potentially due to the ability of the cell to export HSPs to the extracellular space (eHSP). The increase in eHSPs can contribute to oxidative damage and is associated with various pro-inflammatory pathways in T2D and AD. Here, we review the role of HSP in moderating T2D and AD, as well as propose that these chaperone proteins are an important link in the relationship between T2D and AD.

Heat shock protein 60 and cardiovascular diseases: An intricate love-hate story

Cardiovascular diseases (CVDs) are the result of complex pathophysiological processes in the tissues comprising the heart and blood vessels. Inflammation is the main culprit for the development of cardiovascular dysfunction, and it may be traced to cellular stress events including apoptosis, oxidative and shear stress, and cellular and humoral immune responses, all of which impair the system's structure and function. An intracellular chaperone, heat shock protein 60 (HSP60) is an intriguing example of a protein that may both be an ally and a foe for cardiovascular homeostasis; on one hand providing protection against cellular injury, and on the other triggering damaging responses through innate and adaptive immunity. In this review we will discuss the functions of HSP60 and its effects on cells and the immune system regulation, only to later address its implications in the development and progression of CVD. Lastly, we summarize the outcome of various studies targeting HSP60 as a potential therapeutic strategy for cardiovascular and other diseases.

Clinicopathological Significance of Heat Shock Protein (HSP) 27 Expression in Gastric Cancer: A Updated Meta-Analysis

Aim

HSP27 is a protein chaperone protecting cell from heat shock, and upregulated HSP27 expression has been found in many different cancers. We conduct this update meta-analysis to evaluate the relationship between HSP27 expression and clinicopathological features.

Methods

We searched PubMed, Chinese CNKI, and WanFang databases to identify studies that assessed the association between clinicopathological feature and HSP27 expression in gastric cancer patients.

Results

We found overexpression of HSP27 was associated with incidence of gastric cancer (OR = 6.31, 95% CI = 1.10–36.15, P < 0.0001). However, there was no significant difference between HSP27 expression and gastric cancer differentiation, gender difference, lymph node metastasis, and distant metastasis.

Conclusion

Our meta-analysis study indicates that overexpression of HSP27 is associated with incidence of gastric cancer statistically.

Dehydration stress alters the mitogen-activated-protein kinase signaling and chaperone stress response in Xenopus laevis

In arid conditions, the African Clawed frog Xenopus laevis enters a state of estivation dormancy as an adaptive survival strategy. Under estivation, X. laevis experience severe dehydration stress as 25-35% of total body water is lost. Dehydration in X. laevis can lead to periods of hypoxia due to elevated blood viscosity that impedes tissue perfusion. To understand how X. laevis survives under such stress, we studied the regulation pattern of key mitogen-activated protein kinases (MAPK) and their downstream transcription factors, along with several heat shock proteins in the oxygen sensitive brain and heart tissue of X. laevis under dehydration stress. Our study revealed that the activation phosphorylation residues of MAPK including JNK and MSK and their downstream transcription factors c-Jun and ATF2 are significantly decreased in the heart under dehydration. Given that JNK, c-Jun, and ATF2 are known positive regulators of apoptosis, this regulatory pattern suggest that a state of pro-survival signals may be established in the dehydrated heart. In support of this, protein levels of HSP60, a pro-apoptotic mitochondrial chaperone, was also downregulated in the heart in response to dehydration stress. In the brain tissue, most proteins remain unchanged with the exception of the apoptosis regulating p53 transcription factor, which showed a significant decrease in its activating phosphorylation residue under dehydration. Overall, our study revealed that in the Xenopus brain and heart, a specific suppression pattern of MAPK, transcription factors, and HSP takes place to potentially establish a state of pro-survival under dehydration stress.

Structural basis for active single and double ring complexes in human mitochondrial Hsp60-Hsp10 chaperonin

mHsp60-mHsp10 assists the folding of mitochondrial matrix proteins without the negative ATP binding inter-ring cooperativity of GroEL-GroES. Here we report the crystal structure of an ATP (ADP:BeF₃-bound) ground-state mimic double-ring mHsp60₁₄-(mHsp10₇)₂ football complex, and the cryo-EM structures of the ADP-bound successor mHsp60₁₄-(mHsp10₇)₂ complex, and a single-ring mHsp60₇-mHsp10₇ half-football. The structures explain the nucleotide dependence of mHsp60 ring formation, and reveal an inter-ring nucleotide symmetry consistent with the absence of negative cooperativity. In the ground-state a two-fold symmetric H-bond and a salt bridge stitch the double-rings together, whereas only the H-bond remains as the equatorial gap increases in an ADP football poised to split into half-footballs. Refolding assays demonstrate obligate single- and double-ring mHsp60 variants are active, and complementation analysis in bacteria shows the single-ring variant is as efficient as wild-type mHsp60. Our work provides a structural basis for active single- and double-ring complexes coexisting in the mHsp60-mHsp10 chaperonin reaction cycle.

Heat Shock Protein 60 in Hepatocellular Carcinoma: Insights and Perspectives

Heat shock protein 60 (HSP60) is a mitochondrial chaperone that is implicated in physiological and pathological processes. For instance, it contributes to protein folding and stability, translocation of mitochondrial proteins, and apoptosis. Variations in the expression levels of HSP60 have been correlated to various diseases and cancers, including hepatocellular carcinoma (HCC). Unlike other HSPs which clearly increase in some cancers, data about HSP60 levels in HCC are controversial and difficult to interpret. In the current review, we summarize and simplify the current knowledge about the role of HSP60 in HCC. In addition, we highlight the possibility of its targeting, using chemical compounds and/or genetic tools for treatment of HCC.

Functional Compartmentalization of HSP60-Survivin Interaction between Mitochondria and Cytosol in Cancer Cells

Heat shock protein 60 (HSP60) and survivin reside in both the cytosolic and mitochondrial compartments under physiological conditions. They can form HSP60-survivin complexes through protein–protein interactions. Their expression levels in cancer tissues are positively correlated and higher expression of either protein is associated with poor clinical prognosis. The subcellular location of HSP60-survivin complex in either the cytosol or mitochondria is cell type-dependent, while the biological significance of HSP60-survivin interaction remains elusive. Current knowledge indicates that the function of HSP60 partly rests on where HSP60-survivin interaction takes place. HSP60 has a pro-survival function when binding to survivin in the mitochondria through interacting with other factors such as CCAR2 and p53. In response to cell death signals, mitochondrial survivin functions through preventing procaspase activation. Degradation of cytosolic survivin leads to the loss of mitochondrial membrane potential and aberrant mitosis processes. On the other hand, HSP60 release from mitochondria to cytosol upon death stimuli might exert a pro-death function, either through stabilizing Bax, enhancing procaspase-3 activation, or increasing protein ubiquitination. Combining the knowledge of mitochondrial HSP60-survivin complex function, cytosolic survivin degradation effect, and pro-death function upon mitochondria release of HSP60, a hypothetical scenario for HSP60-survivin shuttling upon death stimuli is proposed.

Heat Shock Proteins in Glioblastoma Biology: Where Do We Stand?

Heat shock proteins (HSPs) are evolutionary conserved proteins that work as molecular chaperones and perform broad and crucial roles in proteostasis, an important process to preserve the integrity of proteins in different cell types, in health and disease. Their function in cancer is an important aspect to be considered for a better understanding of disease development and progression. Glioblastoma (GBM) is the most frequent and lethal brain cancer, with no effective therapies. In recent years, HSPs have been considered as possible targets for GBM therapy due their importance in different mechanisms that govern GBM malignance. In this review, we address current evidence on the role of several HSPs in the biology of GBMs, and how these molecules have been considered in different treatments in the context of this disease, including their activities in glioblastoma stem-like cells (GSCs), a small subpopulation able to drive GBM growth. Additionally, we highlight recent works that approach other classes of chaperones, such as histone and mitochondrial chaperones, as important molecules for GBM aggressiveness. Herein, we provide new insights into how HSPs and their partners play pivotal roles in GBM biology and may open new therapeutic avenues for GBM based on proteostasis machinery.

Heat Shock Proteins and Ovarian Cancer: Important Roles and Therapeutic Opportunities

Ovarian cancer is a serious cause of death in gynecological oncology. Delayed diagnosis and poor survival rates associated with late stages of the disease are major obstacles against treatment efforts. Heat shock proteins (HSPs) are stress responsive molecules known to be crucial in many cancer types including ovarian cancer. Clusterin (CLU), a unique chaperone protein with analogous oncogenic criteria to HSPs, has also been proven to confer resistance to anti-cancer drugs. Indeed, these chaperone molecules have been implicated in diagnosis, prognosis, metastasis and aggressiveness of various cancers. However, relative to other cancers, there is limited body of knowledge about the molecular roles of these chaperones in ovarian cancer. In the current review, we shed light on the diverse roles of HSPs as well as related chaperone proteins like CLU in the pathogenesis of ovarian cancer and elucidate their potential as effective drug targets.

HSP60-regulated Mitochondrial Proteostasis and Protein Translation Promote Tumor Growth of Ovarian Cancer

Ovarian cancer (OC) is the most lethal gynecological carcinoma due to the lack of diagnostic markers and effective drug targets. Discovery of new therapeutic targets in OC to improve the treatment outcome is urgently needed. We performed proteomic analysis of OC specimens and the paired normal tissues and revealed that proteins associated with mitochondrial proteostasis and protein translation were highly expressed in ovarian tumor tissues, indicating that mitochondria are required for tumor progression of OC. Heat shock protein 60 (HSP60), an important mitochondrial chaperone, was upregulated in ovarian tumors. HSP60 silencing significantly attenuated growth of OC cells in both cells and mice xenografts. Proteomic analysis revealed that HSP60 silencing downregulated proteins involved in mitochondrial functions and protein synthesis. Metabolomic analysis revealed that HSP60 silencing resulted in a more than 100-fold increase in cellular adenine levels, leading to increased adenosine monophosphate and an activated AMPK pathway, and consequently reduced mTORC1-mediated S6K and 4EBP1 phosphorylation to inhibit protein synthesis that suppressed the proliferation of OC cells. These results suggest that HSP60 knockdown breaks mitochondrial proteostasis, and inactivates the mTOR pathway to inhibit OC progression, suggesting that HSP60 is a potential therapeutic target for OC treatment.

Cabazitaxel inhibits prostate cancer cell growth by inhibition of androgen receptor and heat shock protein expression

PURPOSE

Cabazitaxel, a semi-synthetic taxane of the third generation, inhibits prostate cancer (PC) cell growth by affecting the microtubule architecture. Since cabazitaxel has also been demonstrated to inhibit androgen receptor (AR) functionality, AR and AR-associated heat shock protein (HSP) expressions in the presence of cabazitaxel were characterized.

METHODS

AR and HSP expressions were assessed via Western blotting utilizing a PC-cell-line in vitro system incubated with cabazitaxel.

RESULTS

Incubation experiments with 0.3 nM cabazitaxel exhibited significantly reduced levels of AR and the AR-associated factors HSP90α, HSP40, and HSP70/HSP90 organising protein. Furthermore, expression of the anti-apoptotic factor HSP60 was suppressed. In contrast to other anticancer compounds, cabazitaxel did not alter the cytoprotective chemoresistance factor HSP27.

CONCLUSIONS

Despite the deregulation of microtubule organisation, cabazitaxel has been shown to suppress the expression of HSP. Very notably, and may be as a result of down-regulated HSP, cabazitaxel additionally inhibits the expression of the AR in AR-positive PC cells. Thus, cabazitaxel bears an additional anti-proliferative activity which is at least in part specific for PC cells.

CCAR2/DBC1 and Hsp60 Positively Regulate Expression of Survivin in Neuroblastoma Cells

CCAR2 (cell cycle and apoptosis regulator 2) controls a variety of cellular functions; however, its main function is to regulate cell survival and cell death in response to genotoxic and metabolic stresses. Recently, we reported that CCAR2 protects cells from apoptosis following mitochondrial stress, possibly by co-operating with Hsp60. However, it is not clear how CCAR2 and Hsp60 control cell survival and death. Here, we found that depleting CCAR2 and Hsp60 downregulated expression of survivin, a member of the inhibitor of apoptosis (IAP) family. Survivin expression in neuroblastoma tissues and human cancer cell lines correlated positively with expression of CCAR2 and Hsp60. Furthermore, high expression of CCAR2, Hsp60, and survivin was associated with poor survival of neuroblastoma patients. In summary, both CCAR2 and Hsp60 are required for expression of survivin, and both promote cancer cell survival, at least in part, by maintaining survivin expression. Therefore, CCAR2, Hsp60, and survivin are candidate tumor biomarkers and prognostic markers in neuroblastomas.

Heat Shock Proteins in Alzheimer's Disease: Role and Targeting

Among diseases whose cure is still far from being discovered, Alzheimer’s disease (AD) has been recognized as a crucial medical and social problem. A major issue in AD research is represented by the complexity of involved biochemical pathways, including the nature of protein misfolding, which results in the production of toxic species. Considering the involvement of (mis)folding processes in AD aetiology, targeting molecular chaperones represents a promising therapeutic perspective. This review analyses the connection between AD and molecular chaperones, with particular attention toward the most important heat shock proteins (HSPs) as representative components of the human chaperome: Hsp60, Hsp70 and Hsp90. The role of these proteins in AD is highlighted from a biological point of view. Pharmacological targeting of such HSPs with inhibitors or regulators is also discussed.

Listeria Adhesion Protein Induces Intestinal Epithelial Barrier Dysfunction for Bacterial Translocation

Intestinal epithelial cells are the first line of defense against enteric pathogens, yet bacterial pathogens, such as Listeria monocytogenes, can breach this barrier. We show that Listeria adhesion protein (LAP) induces intestinal epithelial barrier dysfunction to promote bacterial translocation. These disruptions are attributed to the production of pro-inflammatory cytokines TNF-α and IL-6, which is observed in mice challenged with WT and isogenic strains lacking the surface invasion protein Internalin A (ΔinlA), but not a lap^- mutant. Additionally, upon engagement of its surface receptor Hsp60, LAP activates canonical NF-κB signaling, facilitating myosin light-chain kinase (MLCK)-mediated opening of the epithelial barrier via cellular redistribution of the epithelial junctional proteins claudin-1, occludin, and E-cadherin. Pharmacological inhibition of MLCK or NF-κB in cells or genetic ablation of MLCK in mice prevents mislocalization of junctional proteins and L. monocytogenes translocation. Thus, L. monocytogenes uses LAP to exploit epithelial defenses and cross the intestinal epithelial barrier.

Chaperonin of Group I: Oligomeric Spectrum and Biochemical and Biological Implications

Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM), is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still incompletely understood. Chaperonin I in eukaryotes occurs in various locations, not just the mitochondrion, which is its canonical place of residence and function. Eukaryotic Chaperonin I, namely Hsp60 (designated HSP60 or HSPD1 in humans) has, indeed, been found in the cytosol; the plasma-cell membrane; on the outer surface of cells; in the intercellular space; in biological liquids such as lymph, blood, and cerebrospinal fluid; and in secretions, for instance saliva and urine. Hsp60 has also been found in cell-derived vesicles such as exosomes. The functions of Hsp60 in all these non-canonical locales are still poorly characterized and one of the questions not yet answered is in what form, i.e., monomer or oligomer, is the chaperonin present in these non-canonical locations. In view of the steady increase in interest on chaperonopathies over the last several years, we have studied human HSP60 to determine its role in various diseases, its locations in cells and tissues and migrations in the body, and its post-translational modifications that might have an impact on its location and function. We also carried out experiments to characterize the oligomeric status of extramitochondrial of HSP60 in solution. Here, we provide an overview of our results, focusing on the oligomeric equilibrium and stability of the various forms of HSP60 in comparison with GroEL. We also discuss post-translational modifications associated with anti-cancer drugs to indicate the potential of Hsp60 in Medicine, as a biomarker and etiopathogenic factor.

The regulation of heat shock proteins in response to dehydration in Xenopus laevis

African clawed frogs (Xenopus laevis) endure bouts of severe drought in their natural habitats and survive the loss of approximately 30% of total body water due to dehydration. To investigate molecular mechanisms employed by X. laevis during periods of dehydration, the heat shock protein response, a vital component of the cytoprotective stress response, was characterized. Using western immunoblotting and multiplex technology, the protein levels of HSP27, HSP40, HSP60, HSP70, HSC70, and HSP90 were quantified in the liver, skeletal muscle, kidney, lung, and testes from control frogs and those that underwent medium or high dehydration (~16 or ~30% loss of total body water). Dehydration increased HSP27 (1.45-1.65-fold) in the kidneys and lungs, and HSP40 (1.39-2.50-fold) in the liver, testes, and skeletal muscle. HSP60 decreased in response to dehydration (0.43-0.64 of control) in the kidneys and lungs. HSP70 increased in the liver, lungs, and testes (1.39-1.70-fold) during dehydration, but had a dynamic response in the kidneys (levels increased 1.57-fold with medium dehydration, but decreased to 0.56 of control during high dehydration). HSC70 increased in the liver and kidneys (1.20-1.36-fold), but decreased in skeletal muscle (0.27-0.55 of control) during dehydration. Lastly, HSP90 was reduced in the kidney, lung, and skeletal muscle (0.39-0.69 of control) in response to dehydration, but rose in the testes (1.30-fold). Overall, the results suggest a dynamic tissue-specific heat shock protein response to whole body dehydration in X. laevis.

Immunohistochemical Expression of Caspase-3 in Psoriasis

INTRODUCTION

Psoriasis is a persistent chronic immune-mediated, relapsing, inflammatory and hyper proliferative skin disorder with genetic predisposition. Psoriasis can be considered as a T-cell mediated disease, with a complex role for a variety of cytokine interaction between keratinocytes and T-lymphocytes. Caspase-3 is an enzyme that plays a key role in apoptosis; it is a member of the family of cysteinyle aspartate specific proteases.

AIM

To evaluate the expression of caspase-3 in Egyptian psoriasis patients and its role in apoptosis of keratinocytes. Also, to correlate this expression with the clinicopathological parameters in order to identify the possible hypothesized role of caspase-3 in the pathogenesis of psoriasis.

MATERIALS AND METHODS

This was a case-control study conducted on patients suffering from chronic plaque psoriasis. A total of 20 psoriasis patients and 10 controls were selected from outpatient clinic of Dermatology, Menoufia University Hospital, between the period of October 2014 and January 2016. From each patient and control, a punch biopsy was taken. Evaluation of H&E stained sections and caspase-3 expression was done using standard immunohi-stochemical techniques. Non-parametric chi-square test, Mann-Whitney U test, Kruskal Wallis test and Spearman's coefficient test were the statistical tests used.

RESULTS

High caspase-3 H score was significantly in favour of psoriatic group in comparison with the control group. On the contrary, in the dermis, caspase-3 was significantly higher in skin adnexa while completely absent in the psoriatic group. Strong caspase-3 expression was significantly in favour of high PASI score, early onset lesions and lesions in the extremities. Significant positive correlation was found between caspase-3 percent and PASI score (r= +0.53, p-value=0.03).

CONCLUSION

Caspase-3 over expression in the psoriatic lesion proposes a potential role in the pathogenesis of psoriasis. Positive correlation between the caspase-3 expression and the early onset psoriatic lesion located in the extremities implies a possible poor prognostic impact of caspase-3 over expression.

Exploring the TRAILs less travelled: TRAIL in cancer biology and therapy

The discovery that the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis of cancer cells without causing toxicity in mice has led to the in-depth study of pro-apoptotic TRAIL receptor (TRAIL-R) signalling and the development of biotherapeutic drug candidates that activate TRAIL-Rs. The outcome of clinical trials with these TRAIL-R agonists has, however, been disappointing so far. Recent evidence indicates that many cancers, in addition to being TRAIL resistant, use the endogenous TRAIL-TRAIL-R system to their own advantage. However, novel insight on two fronts - how resistance of cancer cells to TRAIL-based pro-apoptotic therapies might be overcome, and how the pro-tumorigenic effects of endogenous TRAIL might be countered - gives reasonable hope that the TRAIL system can be harnessed to treat cancer. In this Review we assess the status quo of our understanding of the biology of the TRAIL-TRAIL-R system - as well as the gaps therein - and discuss the opportunities and challenges in effectively targeting this pathway.

Thermoregulation as a disease tolerance defense strategy

Physiological responses that occur during infection are most often thought of in terms of effectors of microbial destruction through the execution of resistance mechanisms, due to a direct action of the microbe, or are maladaptive consequences of host-pathogen interplay. However, an examination of the cellular and organ-level consequences of one such response, thermoregulation that leads to fever or hypothermia, reveals that these actions cannot be readily explained within the traditional paradigms of microbial killing or maladaptive consequences of host-pathogen interactions. In this review, the concept of disease tolerance is applied to thermoregulation during infection, inflammation and trauma, and we discuss the physiological consequences of thermoregulation during disease including tissue susceptibility to damage, inflammation, behavior and toxin neutralization.

Tyrosine phosphorylation modulates mitochondrial chaperonin Hsp60 and delays rotavirus NSP4-mediated apoptotic signaling in host cells

Phosphoproteomics-based platforms have been widely used to identify post translational dynamics of cellular proteins in response to viral infection. The present study was undertaken to assess differential tyrosine phosphorylation during early hours of rotavirus (RV) SA11 infection. Heat shock proteins (Hsp60) were found to be enriched in the data set of RV-SA11 induced differentially tyrosine-phosphorylated proteins at 2 hr post infection (hpi). Hsp60 was further found to be phosphorylated by an activated form of Src kinase on 227th tyrosine residue, and tyrosine phosphorylation of mitochondrial chaperonin Hsp60 correlated with its proteasomal degradation at 2-2.5hpi. Interestingly, mitochondrial Hsp60 positively influenced translocation of the rotaviral nonstructural protein 4 to mitochondria during RV infections. Phosphorylation and subsequent transient degradation of mitochondrial Hsp60 during early hours of RV-SA11 infection resulted in inhibition of premature import of nonstructural protein 4 into mitochondria, thereby delaying early apoptosis. Overall, the study highlighted one of the many strategies rotavirus undertakes to prevent early apoptosis and subsequent reduced viral progeny yield.

Developmental proteome dynamics of silk glands in the 5th instar larval stage of Bombyx mori L (CSR2×CSR4)

Bivoltine breed of Bombyx mori (B. mori), CSR2×CSR4 is an Indian high yielding silkworm strain. Silk gland proteome of this strain was not studied till now. Methods of improving silk production by chemical approaches have reached saturation and transgenic methods are needed in further to boost silk production. An understanding of proteomic changes during silk gland development helps in designing experiments to enhance silk production by transgenic approaches. The present study reports comprehensive developmental proteomic analysis of CSR2×CSR4, 5th instar whole silk glands. Eighty six unique protein IDs were obtained from the analysis of one hundred and twenty protein spots. Among the identified proteins, majority of the proteins were involved in metabolism (41%) followed by proteins involved in protein homeostasis (30%). Sixty percent of the identified proteins showed dynamic nature by expression analysis from day 1, day 3, day 5 and day 7 gels. In comparison to the published data till now on silk gland proteomics this study reports identification of 20 new proteins from the silk glands for the first time.

SIGNIFICANCE

The paper reports for the first time proteomic analysis of high yielding silkworm strain of India. The study analyzes whole silk glands to understand the tissue in total during 5th instar development. Lowering fibroin content made us to identify a large number of new proteins which were not reported till now in the silk gland proteome. Proteins which are involved in silk synthesis and release were found to be developmentally regulated. The study identified alanine, serine and glycine tRNA ligases for the first time and also showed their up-regulation on day 7 of 5th instar larval stage. The amino acid repeat of fibroin protein is enriched with the three amino acids, glycine, serine and alanine. The identified proteins could be studied further to understand their functional role in-depth.

Characterization and function analysis of Hsp60 and Hsp10 under different acute stresses in black tiger shrimp, Penaeus monodon

Heat shock proteins (Hsps) are a class of highly conserved proteins produced in virtually all living organisms from bacteria to humans. Hsp60 and Hsp10, the most important mitochondrial chaperones, participate in environmental stress responses. In this study, the full-length complementary DNAs (cDNAs) of Hsp60 (PmHsp60) and Hsp10 (PmHsp10) were cloned from Penaeus monodon. Sequence analysis showed that PmHsp60 and PmHsp10 encoded polypeptides of 578 and 102 amino acids, respectively. The expression profiles of PmHsp60 and PmHsp10 were detected in the gills and hepatopancreas of the shrimps under pH challenge, osmotic stress, and heavy metal exposure, and results suggested that PmHsp60 and PmHsp10 were involved in the responses to these stimuli. ATPase and chaperone activity assay indicated that PmHsp60 could slow down protein denaturation and that Hsp60/Hsp10 may be combined to produce a chaperone complex with effective chaperone and ATPase activities. Overall, this study provides useful information to help further understand the functional mechanisms of the environmental stress responses of Hsp60 and Hsp10 in shrimp.

A HSP60-targeting peptide for cell apoptosis imaging

Apoptosis has a critical role in both physiological and pathological processes, and therefore probes that enable direct and fast visualization for apoptosis in vitro and in vivo have great significance for evaluation of therapeutic effects, disease monitoring and drug screening. We report here a novel apoptotic marker heat shock protein 60 (HSP60)-based apoptosis imaging probe, P17. In this study, we show that P17 can label multiple drug-induced apoptotic cells in vitro, and the difference in binding intensities between apoptotic and viable cells by fluorescent P17 is more than 10-fold in six cell lines measured by flow cytometry and proportional to the apoptotic level of the cells. We further visualized the apoptosis in the subcutaneous tumor of mice by vein injection of P17 using in vivo fluorescent imaging. P17 was identified to bind specifically to HSP60 accumulated in apoptotic cells by pull-down experiments and mass spectrometry. Furthermore, the P17 binding was correlated with the apoptotic feature of phosphatidylserine (PS) exposure and caspase-3 activation. We also clarify that P17 labels the cells in late stage apoptosis by double staining with different stage markers, unveiling that HSP60 may be involved with late stage of apoptosis. Overall, this study has demonstrated that P17 is a novel apoptosis probe targeting HSP60 and promising for the detection of apoptosis in vitro and in vivo.

Heat shock proteins in the context of photodynamic therapy: autophagy, apoptosis and immunogenic cell death

Heat shock proteins can mediate resistance to photodynamic therapy by inhibiting apoptosis and modulating autophagy which, in turn, prevents apoptosis and immunogenic cell death.

Anti-breast tumor activity of Eclipta extract in-vitro and in-vivo: novel evidence of endoplasmic reticulum specific localization of Hsp60 during apoptosis

Major challenges for current therapeutic strategies against breast cancer are associated with drug-induced toxicities. Considering the immense potential of bioactive phytochemicals to deliver non-toxic, efficient anti-cancer therapeutics, we performed bio-guided fractionation of Eclipta alba extract and discovered that particularly the chloroform fraction of Eclipta alba (CFEA) is selectively inducing cytotoxicity to breast cancer cells over non-tumorigenic breast epithelial cells. Our unbiased mechanistic hunt revealed that CFEA specifically activates the intrinsic apoptotic pathway by disrupting the mitochondrial membrane potential, upregulating Hsp60 and downregulating the expression of anti-apoptotic protein XIAP. By utilizing Hsp60 specific siRNA, we identified a novel pro-apoptotic role of Hsp60 and uncovered that following CFEA treatment, upregulated Hsp60 is localized in the endoplasmic reticulum (ER). To our knowledge, this is the first evidence of ER specific localization of Hsp60 during cancer cell apoptosis. Further, our LC-MS approach identified that luteolin is mainly attributed for its anti-cancer activities. Moreover, oral administration of CFEA not only offers potential anti-breast cancer effects in-vivo but also mitigates tumor induced hepato-renal toxicity. Together, our studies offer novel mechanistic insight into the CFEA mediated inhibition of breast cancer and may potentially open up new avenues for further translational research.

Neonatal Death and Heart Failure in Mouse with Transgenic HSP60 Expression

Mitochondrial heat shock proteins, such as HSP60, are chaperones responsible for the folding, transport, and quality control of mitochondrial matrix proteins and are essential for maintaining life. Both prosurvival and proapoptotic roles have been proposed for HSP60, and HSP60 is reportedly involved in the initiation of autoimmune, metabolic, and cardiovascular diseases. The role of HSP60 in pathogenesis of these diseases remains unclear, partly because of the lack of mouse models expressing HSP60. In this study we generated HSP60 conditional transgenic mice suitable for investigating in vivo outcomes by expressing HSP60 at the targeted organ in disease models. Ubiquitous HSP60 induction in the embryonic stage caused neonatal death in mice at postnatal day 1. A high incidence of atrial septal defects was observed in HSP60-expressing mice, with increased apoptosis and myocyte degeneration that possibly contributed to massive hemorrhage and sponge-like cardiac muscles. Our results showed that neonatal heart failure through HSP60 induction likely involves developmental defects and excessive apoptosis. The conditional HSP60 mouse model is useful for studying crucial biological questions concerning HSP60.