Title:Cathepsin D Attenuates the Proliferation of Vascular Smooth Muscle Cells
Induced by the AGE/RAGE Pathway by Suppressing the ERK Signal
Volume: 29
Issue: 30
Author(s): Ning Ye, Linlin Miao, Fengzhi Wang, Shaojun Wu, Boquan Wu, Ying Zhou, Chang Wang and Guozhe Sun*
Affiliation:
- Department of Cardiovascular Medicine, The First Hospital of China Medical University, Shenyang, Liaoning 110001, China
Keywords:
Vascular smooth muscle cells, advanced glycation end products, Cathepsin D, phenotypic switch, proliferation, ERK signal.
Abstract:
Background: In this study, we aimed to clarify the role and mechanism by which Cathepsin D
(CTSD) mediates the advanced glycation end products (AGEs)-induced proliferation of vascular smooth muscle
cells (VSMCs).
Methods: We conducted a Western blotting assay and co-immunoprecipitation assay to detect the expression
of target proteins and the interaction between different proteins. Cell Counting Kit-8 (CCK-8) assay and 5-
ethynyl-2’-deoxyuridine (EdU) were used to evaluate the proliferation.
Results: AGEs significantly promoted phenotypic switching and proliferation of VSMCs in a concentration-dependent
manner. This effect of AGEs was accompanied by inhibition of CTSD. Both the proliferation of
VSMCs and inhibition of CTSD induced by AGEs could be attenuated by the specific inhibitor of the receptor
for advanced glycation end products (RAGE), FPS-ZM1. Overexpression of CTSD significantly alleviated these
effects of AGEs on VSMCs. The mechanism of CTSD action in VSMCs was also explored. Overexpression
of CTSD reduced the activation of p-ERK caused by AGEs. By contrast, the knockdown of CTSD, elicited
using a plasmid containing short hairpin RNA (shRNA) against CTSD, further increased the activation of
p-ERK compared to AGEs alone. Additionally, co-immunoprecipitation studies revealed an endogenous interaction
between CTSD, a protease, and p-ERK, its potential substrate.
Conclusion: It has been demonstrated that CTSD downregulates the level of phosphorylated ERK by degrading
its target, and this interaction plays a critical role in the proliferation of VSMCs induced by the
AGE/RAGE axis. These results provide a novel insight into the prevention and treatment of vascular complications
in diabetes.
