IMR Press / FBL / Volume 27 / Issue 6 / DOI: 10.31083/j.fbl2706184
Open Access Original Research
PINK1/Parkin-Mediated Mitophagy Plays a Protective Role in Albumin Overload-Induced Renal Tubular Cell Injury
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1 Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, 300052 Tianjin, China
*Correspondence: zhangqiangyulv@163.com (Qiang Zhang)
These authors contributed equally.
Academic Editor: Mateusz Maciejczyk
Front. Biosci. (Landmark Ed) 2022, 27(6), 184; https://doi.org/10.31083/j.fbl2706184
Submitted: 5 April 2022 | Revised: 28 May 2022 | Accepted: 28 May 2022 | Published: 7 June 2022
Copyright: © 2022 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Proteinuria is an important symptom of chronic kidney disease irrespective of its initial pathogenesis. Mitochondrial dysfunction is an early pathophysiological event in proteinuria-induced tubular damage. Mitophagy, the selective degradation of damaged mitochondria targeted by autophagy, contributes to mitochondrial homeostasis and is primarily regulated by the PTEN-induced kinase 1 (PINK1)/Parkin pathway. In this study, we evaluated the function of mitophagy in proteinuria-induced tubular injury and mechanism. Methods: HK-2 cells were transfected with Parkin siRNA or Parkin overexpression plasmids for 48 h followed by treatment with albumin (8 mg/mL) for 8 h. JC-1 staining, ATP detection, and reactive oxygen species (ROS) detection were used to determine mitochondrial function. Immunoblot, LC3/mitochondria co-localization analyses, and Mito-Keima were employed to detect mitophagy. Immunoblot analysis and TUNEL were used to detect apoptosis. Results: Albumin overload induced mitochondrial dysfunction and mitophagy activation in HK-2 cells. Parkin knockdown inhibited albumin overload induced-mitophagy. Parkin overexpression further upregulated albumin overload induced-mitophagy. Parkin deficiency aggravated albumin overload-induced mitochondrial dysfunction and the overproduction of ROS, resulting in increased cell injury. Contrarily, Parkin overexpression helped maintain mitochondrial function and attenuate ROS generation, contributing to cell protection. Conclusions: Our results suggest that by clearing damaged mitochondria and maintaining mitochondrial function, PINK1/Parkin-mediated mitophagy contributed to tubular cell survival during albumin overload. PINK1/Parkin-mediated mitophagy may be a potential therapeutic target for proteinuria in tubular epithelial cells.

Keywords
renal tubular epithelial cell
proteinuria
mitochondrial dysfunction
mitophagy
PINK1
Parkin
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