Abstract: SA-PO816
Involvement of Endoplasmic Reticulum Stress and Autophagy on Homocysteine Induced Apoptosis of Human Glomerular Mesangial Cells
Session Information
- Molecular Mechanisms of CKD - III
October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 1903 CKD (Non-Dialysis): Mechanisms
Authors
- Liang, Shanshan, Dialysis Department of Nephrology Hospital, First Affiliated Hospital of Medicine School, Xi?an Jiaotong University, Xi?an, China
- Jiang, Hongli, First Affiliated Hospital of Medicine School, Xi?an Jiaotong University, Xi?an, China
Background
Homocysteine (Hcy) levels significantly increased in chronic renal failure (CRF). It has been reported that Hcy can induce proliferation and apoptosis of glomerular Mesangial cells. The purpose of this study was to investigate whether autophagy and endoplasmic reticulum stress were involved in the induction of glomerular Mesangial cells apoptosis by Hcy, and to provide evidence for further elucidation of the toxicity of Hcy on Mesangial cells.
Methods
Human Glomerular Mesangial cells (HMC) were incubated with different concentrations of Hcy (50~1000 μ mol/L) for 24h and Hcy 250 μmol/L for different hours (0~48h). Flow cytometry was used to detect the changes of apoptosis after different concentrations and times of Hcy treatment. Western blotting was used to detect the changes of related proteins after exposure to Hcy 250 μmol/L for 24h. Apoptosis as well as protein changes were separately detected by flow cytometry and Western blotting after treatment with endoplasmic reticulum inhibitor 4-PBA and Atg 5 siRNA respectively.
Results
The proliferation ability and cell viability of HMC gradually decreased. The proportion of Mesangial cell apoptosis increased with the increase of the concentration of Hcy and the prolongation of the incubation times in a time-and concentration-dependent manner. The expression of apoptosis-related protein Bax and cleavage caspase-3 were significantly increased, with the autophagy related proteins LC3-II/LC3-I, beclin1 and Atg5 were significantly increased and p62 decreased. The expression of ER stress-related proteins ATF4, CHOP, GRP78 and p-eIF2α all increased significantly. After the intervention of 4-PBA, the ER stress-related proteins and the proportion of apoptosis decreased with the expression of apoptosis-related protein improved. The expression of p62 increased and LC3-II/LC3-I, beclin1 and Atg5 decreased. At the same time, after intervened with Atg5 siRNA, the expression of Atg5 decreased, and the ratio of LC3-II/LC3-I decreased and the p62 degraded with cleavage caspase-3 and CHOP increased, but p-eIF2α did not change significantly.
Conclusion
Hcy induced glomerular mesangial cell apoptosis in a concentration- and time- dependent manner and may via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role in the process.
Funding
- Government Support - Non-U.S.