Dilated cardiomyopathy-linked heat shock protein family D member 1 mutations cause up-regulation of reactive oxygen species and autophagy through mitochondrial dysfunction

Abstract

Background During heart failure, the levels of circulatory HSPD1 (HSP60) increase. However, its underlying mechanism is still unknown. The apical domain of HSPD1 is conserved throughout evolution. We found a point mutation in HSPD1 in a familial dilated cardiomyopathy (DCM) patient. A similar point mutation in HSPD1 in the zebrafish mutant, nbl, led to loss of its regenerative capacity and development of pericardial edema under heat stress condition. In this study, we aimed to determine the direct involvement of HSPD1 in the development of DCM. Methods and Results By Sanger method, we found a point mutation (Thr320Ala) in the apical domain of HSPD1, in one familial DCM patient, which was four amino acids away from the point mutation (Val324Glu) in the nbl mutant zebrafish. The nbl mutants showed atrioventricular block and sudden death at eight months post-fertilization. Histological and microscopic analysis of the nbl mutant hearts showed decreased ventricular wall thickness, elevated level of reactive oxygen species (ROS), increased fibrosis, mitochondrial damage, and increased autophagosomes. mRNA and protein expression of autophagy-related genes significantly increased in nbl mutants. We established HEK293 stable cell lines of WT, nbl-type, and DCM-type HSPD1, with tetracycline-dependent expression. Compared to WT, both nbl- and DCM-type cells showed decreased cell growth, increased expression of ROS and autophagy-related genes, inhibition of the activity of mitochondrial electron transport chain complexes III and IV, and decreased mitochondrial fission and fusion. Conclusions Mutations in HSPD1 caused mitochondrial dysfunction and induced mitophagy. Mitochondrial dysfunction caused increased ROS and cardiac atrophy. Translational Perspective The aged heart is more susceptible to stress despite the increased compensatory chaperones/co-chaperones activity. Here, we identified a point mutation in HSPD1 in a human DCM family. Using zebrafish, we demonstrated that functional inactivation of HSPD1 resulted in increased ROS level and mitophagy, thereby resulting in heart failure at a relatively early age. Inhibition of ROS activity by antioxidants decreased cell death and mitophagy. This work identifies the key role of HSPD1 in cardiac muscle protection and suggests the supplementation of antioxidants may improve the cardiac function through the mitochondrial ROS pathway in patients with chronic heart failure.

Clinical Significance of HSPD1/MMP14/ITGB1/miR-6881-5P/Lnc-SPARCL1-1:2 RNA Panel in NAFLD/NASH Diagnosis: Egyptian Pilot Study

“…HSPD1 acts as a significant regulator of cytokine production and interacts with interferon regulatory factor 3 (IRF3), which is a player in the NLR and IFN-β signaling pathway [ 46 , 47 , 48 ]. Enomoto et al reported that upregulation of HSPD1 protein inhibited the activity of mitochondrial complex IV, leading to an increase in ROS concentration in cardiac muscle [ 49 ]. Stefano et al found no difference in the expression of HSPD1 in NASH and control groups [ 50 ].…”

Genetics of Peripartum Cardiomyopathy: Current Knowledge, Future Directions and Clinical Implications

“…The HSPD1 gene encodes for a constitutively expressed Hsp60 chaperonin protein. A recent study has linked HSPD1 mutations with cardiomyopathy when the mutation p.Thr320Ala was described in a Japanese family with DCM and arrhythmia [ 69 ]. Although the mechanisms whereby HSPD1 may contribute to cardiomyopathy are unclear, the authors demonstrated that a similar mutation in zebrafish resulted in a DCM phenotype with mitochondrial damage and increased levels of reactive oxygen species, as well as a reduced tolerance to exercise stress [ 69 ].…”

“…A recent study has linked HSPD1 mutations with cardiomyopathy when the mutation p.Thr320Ala was described in a Japanese family with DCM and arrhythmia [ 69 ]. Although the mechanisms whereby HSPD1 may contribute to cardiomyopathy are unclear, the authors demonstrated that a similar mutation in zebrafish resulted in a DCM phenotype with mitochondrial damage and increased levels of reactive oxygen species, as well as a reduced tolerance to exercise stress [ 69 ]. Cardiac-specific deletion of the gene in mice resulted in the development of lethal DCM and HF in males, although the effects in females were not described [ 70 ].…”

Self-eating and Heart: The Emerging Roles of Autophagy in Calcific Aortic Valve Disease

“…To date, the role of autophagy has been unfolded in diverse paramount cardiac pathologies, including left ventricular hypertrophy [ 74 ], cardiomyopathies [ 75 , 76 ], and ischemic injury of the heart [ 77 ]. Despite extensive studies, however, the mechanisms responsible for the effects of autophagy on valvular diseases remain scarce, and no definitive results are available.…”