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Hyperglycemia-induced cardiomyocyte death is mediated by lysosomal membrane injury and aberrant expression of cathepsin D
Journal article   Open access   Peer reviewed

Hyperglycemia-induced cardiomyocyte death is mediated by lysosomal membrane injury and aberrant expression of cathepsin D

Satoru Kobayashi, Fengyi Zhao, Tamayo Kobayashi, Mariko Hagiwara, Amanda Kaminaris, Cairong Li, Fei Cai, Yuan Huang and Qiangrong Liang
Biochemical and biophysical research communications, Vol.523(1), pp.239-245
02/26/2020
DOI: 10.1016/j.bbrc.2019.12.051
PMCID: PMC6941191
PMID: 31862139
url
https://www.ncbi.nlm.nih.gov/pmc/articles/6941191View
Open Access

Abstract

Hyperglycemia is an independent risk factor for diabetic heart failure. However, the mechanisms that mediate hyperglycemia-induced cardiac damage remain poorly understood. Previous studies have shown an association between lysosomal dysfunction and diabetic heart injury. The present study examined if mimicking hyperglycemia in cultured cardiomyocytes could induce lysosomal membrane permeabilization (LMP), leading to the release of lysosome enzymes and subsequent cell death. High glucose (HG) reduced the number of lysosomes with acidic pH as shown by a fluorescent pH indicator. Also, HG induced lysosomal membrane injury as shown by an accumulation of Galectin3-RFP puncta, which was accompanied by the leakage of cathepsin D (CTSD), an aspartic protease that normally resides within the lysosomal lumen. Furthermore, CTSD expression was increased in HG-cultured cardiomyocytes and in the hearts of 2 mouse models of type 1 diabetes. Either CTSD knockdown with siRNA or inhibition of CTSD activity by pepstatin A markedly diminished HG-induced cardiomyocyte death, while CTSD overexpression exaggerated HG-induced cell death. Together, these results suggested that HG increased CTSD expression, induced LMP and triggered CTSD release from the lysosomes, which collectively contributed to HG-induced cardiomyocyte injury. [Display omitted] •Hyperglycemia induced Cathepsin D in mouse heart and in cultured cardiomyocytes.•High glucose increased lysosomal membrane permeability in cultured cardiomyocytes.•High glucose triggered Cathepsin D leakage from the lysosome in cardiomyocytes.•Cathepsin D knockdown or inhibition reduced high glucose cardiotoxicity.•Cathepsin D overexpression exaggerated high glucose-induced cardiomyocyte death.
Cardiomyocyte Cardiomyopathy Cathepsin D Diabetes Hyperglycemia Lysosome

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