Division of Nephrology, Center for Nephrology and Clinical Metabolomics, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.
Department of Nephrology, Qilu Hospital of Shandong University (Qingdao), Qingdao, People's Republic of China.
Clin Exp Nephrol. 2022 Jul;26(7):640-648. doi: 10.1007/s10157-022-02195-z. Epub 2022 Mar 25.
Protein-bound uremic toxins (PBUTs) are reported to be one of the major culprits in chronic kidney disease-cardiovascular disease (CKD-CVD) development, yet its mechanism is not fully clear. Our previous study confirmed elevated expression of integrin-β1 (ITGβ1) in vascular smooth muscle cells of uremic patients. Thus, this study aimed to explore the relationship between PBUTs and ITGβ1 in uremic vasculature injury.
Human umbilical vein smooth muscle cells (HUVSMCs) and endothelial cells (HUVECs) were treated with two representative PUBTs, indoxyl sulfate (IS) and p-cresyl sulfate (PC). Both cells were measured for the expression of ITGβ1 and downstream signaling pathways and assayed for proliferation, migration, adhesion and apoptosis.
The IS treatments were observed with significantly up-regulated ITGβ1 in HUVSMCs but not in HUVECs, while PC did not induce ITGβ1 alteration in either HUVSMCs or HUVECs. Furthermore, overexpression of ITGβ1 revealed activated downstream signal-regulated kinase (ERK) signaling pathway with promoted focal adhesion, migration, proliferation but no apoptosis in HUVSMCs by IS. These functional and pathway alterations could be significantly suppressed by RNA interference of ITGβ1. More importantly, the application of ERK1/2 inhibitor significantly suppressed the focal adhesion, migration and proliferation of HUVSMCs.
We first demonstrated that ITGβ1/ERK signaling pathway mediated abnormal focal adhesion, migration and proliferation of vascular smooth muscle cells stimulated by IS. ITGβ1/ERK signaling may serve as a novel therapeutic target for CKD-CVD.
蛋白结合尿毒症毒素（PBUTs）被认为是慢性肾脏病-心血管疾病（CKD-CVD）发展的主要罪魁祸首之一，但其机制尚不完全清楚。我们之前的研究证实尿毒症患者血管平滑肌细胞中整合素-β1（ITGβ1）表达升高。因此，本研究旨在探讨 PBUTs 与尿毒症血管损伤中 ITGβ1 的关系。
用人脐静脉平滑肌细胞（HUVSMCs）和内皮细胞（HUVECs）分别用两种代表性的 PUBTs，硫酸吲哚酚（IS）和对甲酚硫酸盐（PC）处理。测定 ITGβ1及其下游信号通路在两种细胞中的表达，并测定增殖、迁移、黏附和凋亡。
IS 处理后 HUVSMCs 中 ITGβ1 表达明显上调，但 HUVECs 中无此变化，而 PC 处理后 HUVSMCs 和 HUVECs 中 ITGβ1 均无变化。此外，ITGβ1 过表达可激活下游信号调节激酶（ERK）信号通路，促进 IS 诱导的 HUVSMCs 黏附、迁移和增殖，但不诱导凋亡。这些功能和通路改变可通过 ITGβ1 的 RNA 干扰显著抑制。更重要的是，ERK1/2 抑制剂的应用显著抑制了 HUVSMCs 的黏附、迁移和增殖。
我们首次证明 ITGβ1/ERK 信号通路介导了 IS 刺激的血管平滑肌细胞异常黏附、迁移和增殖。ITGβ1/ERK 信号通路可能成为 CKD-CVD 的一个新的治疗靶点。
