Guang-Jun Wu1, Hong-Biao Zhao2, Xiao-Wei Zhang3. 1. Department of Traditional Chinese Medicine, Linyi Central Hospital, Linyi City, Shandong Province, China. 2. Department of Peripheral Vascular, Linyi Central Hospital, Linyi City, Shandong Province, China. 3. Department of Nephrology, Linyi Central Hospital, Linyi City, Shandong Province, China. pp_zhang11@21cn.com.
Abstract
BACKGROUND: Herein, we aimed to determine whether DAPK1 and its post-transcriptional regulator miR-361 were implicated in high glucose (HG)-induced podocyte injury and renal damage in db/db mice. MATERIALS AND METHODS: Podocytes were incubated with normal glucose (NG; 5 mM) or HG (30 mM). Podocyte apoptosis was evaluated using TUNEL staining. Lentiviral-delivered specific short hairpin RNA (shRNA) was designed to silence DAPK1 expression in podocytes. miR-361 agomir was administrated by tail intravenous injection in db/db diabetic mice to investigate the renoprotection of miR-361 in vivo. RESULTS: Exposure of podocytes to HG led to a significant increase in DAPK1 mRNA and protein levels and a decrease in miR-361 expression levels. Knockdown of DAPK1 attenuated HG-triggered growth inhibition, apoptosis, DNA damage and cell membrane damage in podocytes. Mechanically, DAPK1 was a direct target of miR-361. Transfection with miR-361 mimics into podocytes resulted in a significant decrease in the DAPK1 protein expression level. In addition, HG-induced the up-regulation of the DAPK1 protein expression level in podocytes was restrained by miR-361 mimics transfection. Intriguingly, overexpression of DAPK1 in HG-stimulated podocytes muted miR-361-mediated cytoprotection, including anti-apoptosis, resistance to DNA and membrane damage. In vivo, overexpression of miR-361 protected against hyperglycemia-induced podocyte loss, tubular atrophy and interstitial fibrosis in the kidney of db/db mice. Moreover, overexpression of miR-361 inhibited the protein expression of DAPK1 in the kidney of db/db mice. CONCLUSION: Our research presented a novel mechanism of HG-induced podocyte damage or renal lesion, supporting the miR-361/DAPK1 signaling pathway that could be used as a potential therapeutic target for the treatment of DN.
BACKGROUND: Herein, we aimed to determine whether DAPK1 and its post-transcriptional regulator miR-361 were implicated in high glucose (HG)-induced podocyte injury and renal damage in db/db mice. MATERIALS AND METHODS: Podocytes were incubated with normal glucose (NG; 5 mM) or HG (30 mM). Podocyte apoptosis was evaluated using TUNEL staining. Lentiviral-delivered specific short hairpin RNA (shRNA) was designed to silence DAPK1 expression in podocytes. miR-361 agomir was administrated by tail intravenous injection in db/db diabetic mice to investigate the renoprotection of miR-361 in vivo. RESULTS: Exposure of podocytes to HG led to a significant increase in DAPK1 mRNA and protein levels and a decrease in miR-361 expression levels. Knockdown of DAPK1 attenuated HG-triggered growth inhibition, apoptosis, DNA damage and cell membrane damage in podocytes. Mechanically, DAPK1 was a direct target of miR-361. Transfection with miR-361 mimics into podocytes resulted in a significant decrease in the DAPK1 protein expression level. In addition, HG-induced the up-regulation of the DAPK1 protein expression level in podocytes was restrained by miR-361 mimics transfection. Intriguingly, overexpression of DAPK1 in HG-stimulated podocytes muted miR-361-mediated cytoprotection, including anti-apoptosis, resistance to DNA and membrane damage. In vivo, overexpression of miR-361 protected against hyperglycemia-induced podocyte loss, tubular atrophy and interstitial fibrosis in the kidney of db/db mice. Moreover, overexpression of miR-361 inhibited the protein expression of DAPK1 in the kidney of db/db mice. CONCLUSION: Our research presented a novel mechanism of HG-induced podocyte damage or renal lesion, supporting the miR-361/DAPK1 signaling pathway that could be used as a potential therapeutic target for the treatment of DN.
Authors: Daehyun Baek; Judit Villén; Chanseok Shin; Fernando D Camargo; Steven P Gygi; David P Bartel Journal: Nature Date: 2008-07-30 Impact factor: 49.962