O-GlcNAcylation disrupts STRA6-retinol signals in kidneys of diabetes

• Published in: Biochimica et biophysica acta. General subjects Vol. 1863; no. 6; pp. 1059 - 1069
• Main Authors: Chen, Chao-Hung, Lin, Kun-Der, Ke, Liang-Yin, Liang, Chan-Jung, Kuo, Wen-Chen, Lee, Mei-Yueh, Lee, Yu-Li, Hsiao, Pi-Jung, Hsu, Chih-Cheng, Shin, Shyi-Jang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2019
• Subjects: Acylation; Animals; collagen; Diabetes; Diabetes Mellitus, Experimental - metabolism; Diabetes Mellitus, Experimental - pathology; diabetic complications; Diabetic Nephropathies - metabolism; Diabetic Nephropathies - pathology; Diabetic nephropathy; enzyme-linked immunosorbent assay; high performance liquid chromatography; homeostasis; immunohistochemistry; kidneys; Male; Membrane Proteins - metabolism; Mice; O-GlcNAc; RALDH; RBP4; retinoic acid; Retinol; Signal Transduction; small interfering RNA; STRA6; transfection; transforming growth factor beta 1; vitamin A; Vitamin A - metabolism; Western blotting; RBP4; RALDH; Diabetic nephropathy; Diabetes; O-GlcNAc; Retinol; STRA6
• ISSN: 0304-4165; 1872-8006; 1872-8006
• DOI: 10.1016/j.bbagen.2019.03.014

O-GlcNAcylation is an important mechanism of diabetic complication. Retinoid homeostasis regulates cell-physiological functions through STRA6-retinol signaling. Therefore, we investigated whether O-GlcNAcylation disrupted STRA6-retinol signals in diabetes. Immunoprecipitation and proximity ligation assay were used to investigate O-GlcNAcylation of STRA6-retinol signals in kidneys of db/db and ob/ob mice. Western blot and immunohistochemistry were done for STRA6/CRBP1/LRAT/RALDH1/RARs pathway, GFAT, OGT, TGFβ1 and collagen 1 level. HPLC and ELISA for retinol, retinal, and retinoic acid concentrations were performed in vivo and vitro. RBP4 binding with STRA6 was measured in vitro. To verify whether O-GlcNAcylation disrupted STRA6-retinol signals, treatment of TMG and OSMI-1, transfection of OGA and OGT, and OGT siRNA were performed in HK-2 cells. STRA6 and RALDH1 were highly O-GlcNAc-modified in glomeruli and tubules of db/db and ob/ob mice. RBP4, p-Try, p-JAK2, and p-STAT5 on STRA6 immunoprecipitate were reduced. Cellular retinol signals (CRBP1, LRAT, ADH, retinol, retinal, RA, RARα, RARγ and RXRα) remarkably decreased in kidneys of db/db, ob/ob mice and HG-cultured cells. TMG and OGT transfection induced O-GlcNAcylation of STRA6 and RALDH1, repressed RBP4-bound STRA6, and retinol signals in NG-cultured cells. OSMI-1, OGA transfection, and OGT silence reversed O-GlcNAc-modification of STRA6 and RALDH1, and rescued the decrease of retinol signals, and reversed the increase of TGFβ1 and collagen 1 in HG-treated cells. O-GlcNAcylation significantly modified STRA6 and RALDH1, suppressed RBP4 binding activity, and disrupted retinol signals in the kidney of diabetes. This study first indicates that STRA6-retinol signals were directly disrupted by O-GlcNAcylation in diabetic kidney. •O-GlcNAcylation directly disrupts STRA6-retinol signaling.•O-GlcNAc-modified STRA6 and RALDH1 expresses in diabetic kidney.•O-GlcNAcylation interferes in RBP4 binding to STRA6.