Qing Wu1, Weifeng Fan1, Xiaojing Zhong1, Lihong Zhang1, Jianying Niu1, Yong Gu1,2. 1. Department of Nephrology, Shanghai Fifth People's Hospital, Fudan University Shanghai 200240, China. 2. Department of Nephrology, Huashan Hospital, Fudan University Shanghai 200240, China.
Abstract
OBJECTIVE: Recently, the interaction between Klotho/fibroblast growth factor 23 (FGF-23) axis and Wnt signaling has been recognized to be responsible for chronic kidney disease (CKD)-associated comorbidities, including secondary hyperparathyroidism (SHPT). This study aimed to investigate the molecular mechanism of the interaction between Klotho/FGF23 axis and Wnt. METHODS: A SHPT model was successfully established with a high-phosphorus diet plus 5/6 nephrectomy. Cell counting Kit-8 (CCK-8) assay and calcium deposit experiment were applied to detect the proliferation and calcium levels. Quantitative real-time PCR (qRT-PCR), Western blotting and immunofluorescence (IF) were used to determine the expression or location of FGF23, calcification-related factors and β-catenin after lentivirus-mediated Klotho overexpression. Luciferase reporter assay was performed to further validate the transcriptional regulation between microRNA-29a (miR-29a) and Dickkopf-1 (DDK1). RESULTS: We found increased serum biochemical factors including parathyroid hormone (PTH), phosphorus, calcium, enhanced parathyroid calcification, and decreased expressions of Klotho in a rat model of secondary hyperparathyroidism. Moreover, genetic-induced upregulation of Klotho inhibited the proliferation, reduced the calcification and the alkaline phosphatase (ALP) activity, and downregulated Wnt/β-catenin signaling in parathyroid cells. CONCLUSIONS: Mechanistically, Klotho suppressed miR-29a expression, led to upregulated expression of Wnt/β-catenin signaling inhibitor DKK1, and finally downregulated the activity of Wnt/β-catenin signaling. These findings suggest a novel molecular mechanism in the pathogenesis of CKD-associated SHPT, which provides a potential therapeutic target in the future. AJTR
OBJECTIVE: Recently, the interaction between Klotho/fibroblast growth factor 23 (FGF-23) axis and Wnt signaling has been recognized to be responsible for chronic kidney disease (CKD)-associated comorbidities, including secondary hyperparathyroidism (SHPT). This study aimed to investigate the molecular mechanism of the interaction between Klotho/FGF23 axis and Wnt. METHODS: A SHPT model was successfully established with a high-phosphorus diet plus 5/6 nephrectomy. Cell counting Kit-8 (CCK-8) assay and calcium deposit experiment were applied to detect the proliferation and calcium levels. Quantitative real-time PCR (qRT-PCR), Western blotting and immunofluorescence (IF) were used to determine the expression or location of FGF23, calcification-related factors and β-catenin after lentivirus-mediated Klotho overexpression. Luciferase reporter assay was performed to further validate the transcriptional regulation between microRNA-29a (miR-29a) and Dickkopf-1 (DDK1). RESULTS: We found increased serum biochemical factors including parathyroid hormone (PTH), phosphorus, calcium, enhanced parathyroid calcification, and decreased expressions of Klotho in a rat model of secondary hyperparathyroidism. Moreover, genetic-induced upregulation of Klotho inhibited the proliferation, reduced the calcification and the alkaline phosphatase (ALP) activity, and downregulated Wnt/β-catenin signaling in parathyroid cells. CONCLUSIONS: Mechanistically, Klotho suppressed miR-29a expression, led to upregulated expression of Wnt/β-catenin signaling inhibitor DKK1, and finally downregulated the activity of Wnt/β-catenin signaling. These findings suggest a novel molecular mechanism in the pathogenesis of CKD-associated SHPT, which provides a potential therapeutic target in the future. AJTR
Authors: Juan Rafael Muñoz-Castañeda; Cristian Rodelo-Haad; Maria Victoria Pendon-Ruiz de Mier; Alejandro Martin-Malo; Rafael Santamaria; Mariano Rodriguez Journal: Toxins (Basel) Date: 2020-03-16 Impact factor: 4.546