Int J Biol Sci 2022; 18(14):5438-5458. doi:10.7150/ijbs.74675 This issue

Research Paper

Downregulation of PPARα mediates FABP1 expression, contributing to IgA nephropathy by stimulating ferroptosis in human mesangial cells

Jingkui Wu#, Xinghua Shao#, Jianxiao Shen#, Qisheng Lin, Xuying Zhu, Shu Li, Jialin Li, Wenyan Zhou, Chaojun Qi, Zhaohui Ni

Department of Nephrology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
# These authors contributed equally to this work.

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Citation:
Wu J, Shao X, Shen J, Lin Q, Zhu X, Li S, Li J, Zhou W, Qi C, Ni Z. Downregulation of PPARα mediates FABP1 expression, contributing to IgA nephropathy by stimulating ferroptosis in human mesangial cells. Int J Biol Sci 2022; 18(14):5438-5458. doi:10.7150/ijbs.74675. Available from https://www.ijbs.com/v18p5438.htm

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Abstract

Graphic abstract

Immunoglobulin A nephropathy (IgAN) is the commonest primary glomerulonephritis, and a major cause of end-stage renal disease; however, its pathogenesis requires elucidation. Here, a hub gene, FABP1, and signaling pathway, PPARα, were selected as key in IgAN pathogenesis by combined weighted gene correlation network analysis of clinical traits and identification of differentially expressed genes from three datasets. FABP1 and PPARα levels were lower in IgAN than control kidney, and linearly positively correlated with one another, while FABP1 levels were negatively correlated with urinary albumin-to-creatinine ratio, and GPX4 levels were significantly decreased in IgAN. In human mesangial cells (HMCs), PPARα and FABP1 levels were significantly decreased after Gd-IgA1 stimulation and mitochondria appeared structurally damaged, while reactive oxygen species (ROS) and malondialdehyde (MDA) were significantly increased, and glutathione and GPX4 decreased, relative to controls. GPX4 levels were decreased, and those of ACSL4 increased on siPPARα and siFABP1 siRNA treatment. In PPARα lentivirus-transfected HMCs stimulated by Gd-IgA1, ROS, MDA, and ACSL4 were decreased; glutathione and GPX4, and immunofluorescence colocalization of PPARα and GPX4, increased; and damaged mitochondria reduced. Hence, PPARα pathway downregulation can reduce FABP1 expression, affecting GPX4 and ACSL4 levels, causing HMC ferroptosis, and contributing to IgAN pathogenesis.

Keywords: Immunoglobulin A nephropathy, Peroxisome proliferator-activated receptor α, Fatty acid binding protein 1, Ferroptosis, Human mesangial cells, Weighted gene correlation network analysis