Reticulon-1A mediates diabetic kidney disease progression through endoplasmic reticulum-mitochondrial contacts in tubular epithelial cells

• Published in: Kidney international Vol. 102; no. 2; pp. 293 - 306
• Main Authors: Xie, Yifan, E, Jing, Cai, Hong, Zhong, Fang, Xiao, Wenzhen, Gordon, Ronald E., Wang, Lois, Zheng, Ya-Li, Zhang, Aihua, Lee, Kyung, He, John Cijiang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2022
• Subjects: Albuminuria - metabolism; Animals; Apoptosis; Diabetes Mellitus - metabolism; diabetic kidney disease; Diabetic Nephropathies; Endoplasmic Reticulum - metabolism; Endoplasmic Reticulum Stress; endoplasmic reticulum-mitochondrial contacts; Epithelial Cells - metabolism; Hexokinase - metabolism; Humans; kidney tubular epithelial cells; Mice; Mitochondria - metabolism; Nerve Tissue Proteins - genetics; diabetic kidney disease; endoplasmic reticulum-mitochondrial contacts; endoplasmic reticulum stress; kidney tubular epithelial cells
• ISSN: 0085-2538; 1523-1755; 1523-1755
• DOI: 10.1016/j.kint.2022.02.038

Recent epidemiological studies suggest that some patients with diabetes progress to kidney failure without significant albuminuria and glomerular injury, suggesting a critical role of kidney tubular epithelial cell (TEC) injury in diabetic kidney disease (DKD) progression. However, the major risk factors contributing to TEC injury and progression in DKD remain unclear. We previously showed that expression of endoplasmic reticulum-resident protein Reticulon-1A (RTN1A) increased in human DKD, and the increased RTN1A expression promoted TEC injury through endoplasmic reticulum (ER) stress response. Here, we show that TEC-specific RTN1A overexpression worsened DKD in mice, evidenced by enhanced tubular injury, tubulointerstitial fibrosis, and kidney function decline. But RTN1A overexpression did not exacerbate diabetes-induced glomerular injury or albuminuria. Notably, RTN1A overexpression worsened both ER stress and mitochondrial dysfunction in TECs under diabetic conditions by regulation of ER-mitochondria contacts. Mechanistically, ER-bound RTN1A interacted with mitochondrial hexokinase-1 and the voltage-dependent anion channel-1 (VDAC1), interfering with their association. This disengagement of VDAC1 from hexokinase-1 resulted in activation of apoptotic and inflammasome pathways, leading to TEC injury and loss. Thus, our observations highlight the importance of ER-mitochondrial crosstalk in TEC injury and the salient role of RTN1A-mediated ER-mitochondrial contact regulation in DKD progression. [Display omitted]