Oxidative stress is caused by an imbalance between reactive oxygen species (ROS) production and the ability of an organism to eliminate these toxic intermediates. Mutations in PTEN-inducible kinase 1 (PINK1) link mitochondrial dysfunction, increased sensitivity to ROS, and apoptosis in Parkinson's disease. Whereas PINK1 has been linked to the regulation of oxidative stress, the exact mechanism by which this occurs has remained elusive. Oxidative stress with associated mitochondrial dysfunction leads to cardiac dysfunction and heart failure (HF). We hypothesized that loss of PINK1 in the heart would have deleterious consequences on mitochondrial function. Here, we observed that PINK1 protein levels are markedly reduced in end-stage human HF. We also report that PINK1 localizes exclusively to the mitochondria. PINK1 −/− mice develop left ventricular dysfunction and evidence of pathological cardiac hypertrophy as early as 2 mo of age. Of note, PINK1 −/− mice have greater levels of oxidative stress and impaired mitochondrial function. There were also higher degrees of fibrosis, cardiomyocyte apoptosis, and a reciprocal reduction in capillary density associated with this baseline cardiac phenotype. Collectively, our in vivo data demonstrate that PINK1 activity is crucial for postnatal myocardial development, through its role in maintaining mitochondrial function, and redox homeostasis in cardiomyocytes. In conclusion, PINK1 possesses a distinct, nonredundant function in the surveillance and maintenance of cardiac tissue homeostasis.mitochondrial swelling | mitochonopathy | mitochondrial energetics H eart failure (HF) is the inability of the heart to adequately pump blood to meet the demands of the body. It is the leading cause of morbidity and mortality in North America (1). The quality of life and the prognosis for this group of patients remains poor with 1-y survival rates less than 40% (1). Conventional pharmacological therapy, which only slows the progression of the disease by alleviating the workload of the heart, does not directly target the disease process itself. Alternatives to medical therapy are limited to transplantation or mechanical assist devices; approaches that are themselves associated with significant morbidity and mortality. As such, it is exceedingly important to discover alternate strategies that will effectively treat this disease entity.Oxidative stress is created by the imbalance between production of reactive oxygen species (ROS) and the elimination of toxic intermediates by antioxidant systems. The heart with its high metabolic state and limited capacity for regeneration is particularly sensitive to oxidative stress. Upon exposure to ROS, the heart undergoes hypertrophic growth, a process that involves cell enlargement, myofibrillar disarray, and reexpression of fetal genes (2). Although cardiac hypertrophy is considered an initial adaptive response, prolonged hypertrophy is ultimately detrimental and leads to progressive HF.The discovery of recessively inherited mutations in PTENinducible ...
After mild ischemic insults, many neurons undergo delayed neuronal death. Aberrant activation of the cell cycle machinery is thought to contribute to apoptosis in various conditions including ischemia. We demonstrate that loss of endogenous cyclin-dependent kinase (Cdk) inhibitor p16INK4a is an early and reliable indicator of delayed neuronal death in striatal neurons after mild cerebral ischemia in vivo. Loss of p27 Kip1 , another Cdk inhibitor, precedes cell death in neocortical neurons subjected to oxygen-glucose deprivation in vitro. The loss of Cdk inhibitors is followed by upregulation of cyclin D1, activation of Cdk2, and subsequent cytoskeletal disintegration. Most neurons undergo cell death before entering S-phase, albeit a small number (ϳ1%) do progress to the S-phase before their death. Treatment with Cdk inhibitors significantly reduces cell death in vitro. These results show that alteration of cell cycle regulatory mechanisms is a prelude to delayed neuronal death in focal cerebral ischemia and that pharmacological interventions aimed at neuroprotection may be usefully directed at cell cycle regulatory mechanisms.
Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the ability of an organism to eliminate these toxic intermediates. Although the Parkinson-susceptibility gene, Parkinson protein 7/DJ-1 (DJ-1), has been linked to the regulation of oxidative stress, the exact mechanism by which this occurs and its in vivo relevance have remained elusive. In the heart, oxidative stress is a major contributor to the development of heart failure (HF). Therefore, we hypothesized that DJ-1 inhibits the pathological consequences of ROS production in the heart, the organ with the highest oxidative burden. We report that DJ-1 is highly expressed in normal heart tissue but is markedly reduced in end-stage human HF. DJ-1-deficient mice subjected to oxidative stress by transaortic banding exhibited exaggerated cardiac hypertrophy and susceptibility to developing HF. This was accompanied by a Trp53 (p53)-dependent decrease in capillary density, an excessive oxidation of DNA, and increased cardiomyocyte apoptosis, key events in the development of HF. Impaired mitochondrial biogenesis and progressive respiratory chain deficiency were also evident in cardiomyocytes lacking DJ-1. Our results provide compelling in vivo evidence that DJ-1 is a unique and nonredundant antioxidant that functions independent of other antioxidative pathways in the cellular defense against ROS.cardiomyopathy | angiotensin II | JC-1
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.