Hongxiu Wen1, Vinod Kumar2, Abheepsa Mishra2, Su Song2, Rukhsana Aslam2, Ali Hussain2, Haichao Wang3, Xiaogang Zhou4, Xiaoming He4, Guisheng Wu4, Huairong Luo4, Xiqian Lan5, Ashwani Malhotra2, Pravin C Singhal6. 1. Key Laboratory for Aging and Regenerative Medicine, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Feinstein Institute for Medical Research and Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States. 2. Feinstein Institute for Medical Research and Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States. 3. Feinstein Institute for Medical Research and Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States; Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY, United States. 4. Key Laboratory for Aging and Regenerative Medicine, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China. 5. Key Laboratory for Aging and Regenerative Medicine, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Feinstein Institute for Medical Research and Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States. Electronic address: xlan@swmu.edu.cn. 6. Feinstein Institute for Medical Research and Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, NY, United States. Electronic address: psinghal@northwell.edu.
Abstract
BACKGROUND: Increased DAN protein (Grem1, Grem2, Grem3, Cerberus, NBL1, SOST, and USAG1) levels are often associated with severe disease-states in adult kidneys. Grem1, SOST, and USAG1 have been demonstrated to be upregulated and play a critical role in the progression of diabetic nephropathy (DN); however, the expression and the role of other DAN family members in DN have not been reported yet. In this study, we investigated the expression and the role of Grem2 in the development of renal lesions in mice with type 2 DN. METHODS: Fourteen-week-old BTBRob/ob (a mouse model of type 2 diabetes mellitus) and control (BTBR, wild type) mice were evaluated for renal functional and structural biomarkers. Urine was collected for protein content assay, and renal tissues were harvested for molecular analysis with real-time PCR, Western blotting, and immunohistochemistry. In vitro studies, human podocytes were transfected with Grem2 plasmid and were evaluated for apoptosis (morphologic assay and Western blotting). To evaluate the Grem2-mediated downstream signaling, the phosphorylation status of Smad2/3 and Smad1/5/8 was assessed. To establish a causal relationship, the effect of SIS3 (an inhibitor for Samd2/3) and BMP-7 (an agonist for Smad1/5/8) was evaluated on Germ2-induced podocyte apoptosis. RESULTS: BTBRob/ob mice showed elevated urinary protein levels. Renal tissues of BTBRob/ob mice showed an increased expression of Grem2; both glomerular and tubular cells displayed enhanced Grem2 expression. In vitro studies, high glucose increased Grem2 expression in cultured human podocytes, whereas, Grem2 silencing partially protected podocyte from high glucose-induced apoptosis. Overexpression of Grem2 in podocytes not only increased Bax/Bcl2 expression ratio but also promoted podocyte apoptosis; moreover, an overexpression of Grem2 increased the phosphorylation of Smad2/3 and decreased the phosphorylation of Smad1/5/8; furthermore, SIS3 and BMP-7 attenuated Grem2-induced podocyte apoptosis. CONCLUSIONS: High glucose increases Grem2 expression in kidney cells. Grem2 mediates podocyte apoptosis through Smads.
BACKGROUND: Increased DAN protein (Grem1, Grem2, Grem3, Cerberus, NBL1, SOST, and USAG1) levels are often associated with severe disease-states in adult kidneys. Grem1, SOST, and USAG1 have been demonstrated to be upregulated and play a critical role in the progression of diabetic nephropathy (DN); however, the expression and the role of other DAN family members in DN have not been reported yet. In this study, we investigated the expression and the role of Grem2 in the development of renal lesions in mice with type 2 DN. METHODS: Fourteen-week-old BTBRob/ob (a mouse model of type 2 diabetes mellitus) and control (BTBR, wild type) mice were evaluated for renal functional and structural biomarkers. Urine was collected for protein content assay, and renal tissues were harvested for molecular analysis with real-time PCR, Western blotting, and immunohistochemistry. In vitro studies, human podocytes were transfected with Grem2 plasmid and were evaluated for apoptosis (morphologic assay and Western blotting). To evaluate the Grem2-mediated downstream signaling, the phosphorylation status of Smad2/3 and Smad1/5/8 was assessed. To establish a causal relationship, the effect of SIS3 (an inhibitor for Samd2/3) and BMP-7 (an agonist for Smad1/5/8) was evaluated on Germ2-induced podocyte apoptosis. RESULTS: BTBRob/ob mice showed elevated urinary protein levels. Renal tissues of BTBRob/ob mice showed an increased expression of Grem2; both glomerular and tubular cells displayed enhanced Grem2 expression. In vitro studies, high glucose increased Grem2 expression in cultured human podocytes, whereas, Grem2 silencing partially protected podocyte from high glucose-induced apoptosis. Overexpression of Grem2 in podocytes not only increased Bax/Bcl2 expression ratio but also promoted podocyte apoptosis; moreover, an overexpression of Grem2 increased the phosphorylation of Smad2/3 and decreased the phosphorylation of Smad1/5/8; furthermore, SIS3 and BMP-7 attenuated Grem2-induced podocyte apoptosis. CONCLUSIONS: High glucose increases Grem2 expression in kidney cells. Grem2 mediates podocyte apoptosis through Smads.
Authors: David W Walsh; Sarah A Roxburgh; Paul McGettigan; Celine C Berthier; Desmond G Higgins; Matthias Kretzler; Clemens D Cohen; Sergio Mezzano; Derek P Brazil; Finian Martin Journal: Biochim Biophys Acta Date: 2007-10-11
Authors: Sara Marques; Ana Cristina Borges; Ana Cristina Silva; Sandra Freitas; Michelangelo Cordenonsi; José António Belo Journal: Genes Dev Date: 2004-10-01 Impact factor: 11.361
Authors: Kasi C McPherson; Corbin A Shields; Bibek Poudel; Ashley C Johnson; Lateia Taylor; Cassandra Stubbs; Alyssa Nichols; Denise C Cornelius; Michael R Garrett; Jan M Williams Journal: Am J Physiol Renal Physiol Date: 2020-02-18