Meng Xue1, Feng Yang2, Ying Le1, Yanlin Yang2, Bingsen Wang1, Yijie Jia2, Zongji Zheng2, Yaoming Xue3. 1. Department of Endocrinology and Metabolism, The Second Clinical Medical College, Shenzhen People's HospitalJinan UniversityThe First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China. 2. Department of Endocrinology and Metabolism, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China. 3. Department of Endocrinology and Metabolism, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China. yaomingxue@126.com.
Abstract
BACKGROUND: Diabetic kidney disease (DKD) is a serious complication of diabetes mellitus and results in serious public health problems. Although a great number of studies have been performed to elucidate the mechanisms of this disease, these mechanisms remain largely unknown. METHODS: Cell and animal models were first constructed using human renal proximal tubule cells stimulated by high glucose (HG) and mice induced by streptozotocin (STZ). After Klotho overexpression, Klotho expression was assessed by RT-PCR and western blot, immunofluorescence; autophagy and AMPK/ERK proteins were confirmed using western blot or immunohistochemical assay; the autophagosomes were observed by transmission electron microscope; the pathological structure, fibrosis, polysaccharides and glycogen of kidney were evaluated by H&E staining, Masson staining and PAS staining. RESULTS: We first confirmed that Klotho expression and autophagic activity were reduced in DM mice and HG-induced human renal proximal tubule cells. Besides, overexpression of Klotho could significantly enhance autophagy and AMPK and ERK1/2 activities in vivo and in vitro, which also could be abolished by selective AMPK inhibitor and ERK activator. Moreover, we proved that Klotho could inhibit hyperglycemia-induced renal tubular damage. CONCLUSION: In summary, our results proved that Klotho improved renal tubular cell autophagy via the AMPK and ERK pathways and played a role in renal protection. These findings provide new insight into the mechanism of Klotho and autophagy in DKD.
BACKGROUND: Diabetic kidney disease (DKD) is a serious complication of diabetes mellitus and results in serious public health problems. Although a great number of studies have been performed to elucidate the mechanisms of this disease, these mechanisms remain largely unknown. METHODS: Cell and animal models were first constructed using human renal proximal tubule cells stimulated by high glucose (HG) and mice induced by streptozotocin (STZ). After Klotho overexpression, Klotho expression was assessed by RT-PCR and western blot, immunofluorescence; autophagy and AMPK/ERK proteins were confirmed using western blot or immunohistochemical assay; the autophagosomes were observed by transmission electron microscope; the pathological structure, fibrosis, polysaccharides and glycogen of kidney were evaluated by H&E staining, Masson staining and PAS staining. RESULTS: We first confirmed that Klotho expression and autophagic activity were reduced in DM mice and HG-induced human renal proximal tubule cells. Besides, overexpression of Klotho could significantly enhance autophagy and AMPK and ERK1/2 activities in vivo and in vitro, which also could be abolished by selective AMPK inhibitor and ERK activator. Moreover, we proved that Klotho could inhibit hyperglycemia-induced renal tubular damage. CONCLUSION: In summary, our results proved that Klotho improved renal tubular cell autophagy via the AMPK and ERK pathways and played a role in renal protection. These findings provide new insight into the mechanism of Klotho and autophagy in DKD.
Authors: Sina Münz; Lisa Wolf; Ludwig E Hoelzle; Dmitry Chernyakov; Bayram Edemir; Michael Föller Journal: Aging (Albany NY) Date: 2022-08-22 Impact factor: 5.955