Activation of acetyl-CoA synthetase 2 mediates kidney injury in diabetic nephropathy
Jian Lu, Xue Qi Li, Pei Pei Chen, Jia Xiu Zhang, Liang Liu, Gui Hua Wang, Xiao Qi Liu, Ting Ting Jiang, Meng Ying Wang, Wen Tao Liu, Xiong Zhong Ruan, Kun Ling Ma
Jian Lu, Xue Qi Li, Pei Pei Chen, Jia Xiu Zhang, Liang Liu, Gui Hua Wang, Xiao Qi Liu, Ting Ting Jiang, Meng Ying Wang, Wen Tao Liu, Xiong Zhong Ruan, Kun Ling Ma
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Research Article Metabolism Nephrology

Activation of acetyl-CoA synthetase 2 mediates kidney injury in diabetic nephropathy

Abstract

Albuminuria and podocyte injury are the key cellular events in the progression of diabetic nephropathy (DN). Acetyl-CoA synthetase 2 (ACSS2) is a nucleocytosolic enzyme responsible for the regulation of metabolic homeostasis in mammalian cells. This study aimed to investigate the possible roles of ACSS2 in kidney injury in DN. We constructed an ACSS2-deleted mouse model to investigate the role of ACSS2 in podocyte dysfunction and kidney injury in diabetic mouse models. In vitro, podocytes were chosen and transfected with ACSS2 siRNA and ACSS2 inhibitor and treated with high glucose. We found that ACSS2 expression was significantly elevated in the podocytes of patients with DN and diabetic mice. ACSS2 upregulation promoted phenotype transformation and inflammatory cytokine expression while inhibiting podocytes’ autophagy. Conversely, ACSS2 inhibition improved autophagy and alleviated podocyte injury. Furthermore, ACSS2 epigenetically activated raptor expression by histone H3K9 acetylation, promoting activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway. Pharmacological inhibition or genetic depletion of ACSS2 in the streptozotocin-induced diabetic mouse model greatly ameliorated kidney injury and podocyte dysfunction. To conclude, ACSS2 activation promoted podocyte injury in DN by raptor/mTORC1-mediated autophagy inhibition.

Authors

Jian Lu, Xue Qi Li, Pei Pei Chen, Jia Xiu Zhang, Liang Liu, Gui Hua Wang, Xiao Qi Liu, Ting Ting Jiang, Meng Ying Wang, Wen Tao Liu, Xiong Zhong Ruan, Kun Ling Ma

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Figure 3

Protective effects of ACSS2 deletion on podocyte injury in STZ-induced diabetic mice.

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Protective effects of ACSS2 deletion on podocyte injury in STZ-induced d...
Four groups of mice of control (Ctrl) (n = 6), ACSS2 knockout (ACSS2 KO) (n = 5), diabetes (DM) (n = 6), and ACSS2 knockout with diabetes (ACSS2 KO + DM) (n = 6) were sacrificed at week 12. Data are expressed as mean ± SD or median with interquartile range, *P < 0.05, ***P < 0.001 vs. Ctrl; ##P < 0.01, ###P < 0.001 vs. DM). (A) Representative Western blotting images and densitometric analysis of ACSS2 protein expression in renal cortexes (n = 3 biological replicates, 1-way ANOVA). (B) The level of fasting blood glucose (n = 5–6 biological replicates, 1-way ANOVA). (C) The kidney weight–to–body weight ratio (n = 5–6 biological replicates, 1-way ANOVA). (D) Urinary albumin-to-creatinine ratio (ACR) was detected at weeks 4, 8, and 12 (n = 5–6 biological replicates, 1-way ANOVA). (E) Representative images of PAS-stained kidney sections (original magnification, ×400; scale bars, 100 μm). Bar graph analysis shows the quantification of the mesangial expansion area percentage (n = 10 biological replicates, 1-way ANOVA). (F) Representative images of glomerular ultrastructural change such as podocyte effacement and glomerular basement membrane (GBM) thickness observed by electron microscopy (original magnification ×40,000; scale bars, 1 μm). (G) Representative immunohistochemical staining images of α-SMA and CD68 (original magnification ×200, ×100; scale bars, 50 μm). (H) Representative confocal microscopic images showing the expression of LC3 (green) and WT-1 (red). Nuclei were stained with DAPI (blue). The quantifications of WT-1 (green) per glomerulus in the kidney (n = 20 biological replicates, 1-way ANOVA) were analyzed (original magnification ×400; scale bars, 50 μm). (I) Representative Western blotting images and densitometric analysis of LC3 protein expression (n = 3 biological replicates, 1-way ANOVA).