Grem2 mediates podocyte apoptosis in high glucose milieu
BIOCHIMIE
Authors: Wen, Hongxiu; Kumar, Vinod; Mishra, Abheepsa; Song, Su; Aslam, Rukhsana; Hussain, Ali; Wang, Haichao; Zhou, Xiaogang; He, Xiaoming; Wu, Guisheng; Luo, Huairong; Lan, Xiqian; Malhotra, Ashwani; Singhal, Pravin C.
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. (C) 2019 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.
Cumulus gene expression as a predictor of human oocyte fertilisation, embryo development and competence to establish a pregnancy
REPRODUCTION
Authors: Anderson, R. A.; Sciorio, R.; Kinnell, H.; Bayne, R. A. L.; Thong, K. J.; de Sousa, P. A.; Pickering, S.
Abstract
The close relationship between cumulus cell function and oocyte developmental competence indicates that analysis of cumulus gene expression is a potential non-invasive method to aid embryo selection and lVF outcome. Cumulus was isolated from 674 oocytes from 75 women undergoing ICSI and gene expression analysed by quantitative RT-PCR. Cumulus expression of cyclooxygenase 2 (PTGS2) was higher with mature oocytes, whereas brain-derived neurotrophic factor (BDNF) was lower when fertilisation was normal. Expression levels of gremlin (GREM1) and BDNF were weak positive and negative predictors of embryo quality respectively. Ranking of GREM1 expression within cohorts of oocytes showed that oocytes associated with the highest GREM1 expression were more likely to be transferred or cryopreserved than discarded (49 vs 33%, P<0.02), although the clinical pregnancy rate was not significantly different. This study demonstrates both the feasibility and difficulties of this method of analysis in the largest such group studied thus far. Novel relationships between BDNF expression and fertilisation were identified, and the potential value of GREM1 expression as a marker of embryo quality supports the further assessment of GREM1 analysis in the context of embryo selection. Reproduction (2009) 138 629-637