The Role of Notch1 Pathway Regulating CD4+CD25+Foxp3+ T Cells in Renovascular Hypertension

To explore the role and mechanism of the Notch1 pathway in regulating CD4+CD25+Foxp3+ Treg cells in renal vascular hypertension (RVH). According to the diagnostic criteria of RVH in the 8th edition of Internal Medicine, 220 patients treated in the Department of Nephrology of Sichuan Provincial People’s Hospital from January 2019 to January 2022 were enrolled in RVH group, and 220 patients with essential hypertension (EH) in the same period were selected as EH group; another 220 healthy examinees were selected as control group (NC). The proportion of CD4+CD25+ Treg cells in peripheral blood mononuclear cells (PBMCs) and the expression levels of interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and cell proliferation nuclear antigen-67 (Ki-67) in PBMC of the 3 groups were compared by real-time fluorescence quantitative PCR and western blotting; the relative expression levels of Notch1 receptor and ligand mRNA in PBMC of the 3 groups were compared by real-time fluorescence quantitative PCR; the expression of downstream proteins Hes1 and Hes5 of Notch1 signaling pathway, the proportion of CD4+CD25+Foxp3+ Treg cells, and the effect on TGF-β expression were compared by western blotting after adding Notch1 signaling pathway inhibitor (DAPT). Real-time quantitative PCR and western PCR were used. The proportion of CD4+CD25+ Treg cells in PBMCs and the expression levels of IL-10, TGF-β, and cell proliferating nuclear antigen-67 (Ki-67) in PBMC were compared between the 2 groups. Real-time quantitative PCR was used to compare the mRNA expression levels of the Notch1 receptor and ligand in PBMC between the 2 groups. Flow cytometry results showed that compared with the NC group, the RVH group had a significantly lower proportion of CD4+CD25+Foxp3+ Treg cells, TGF-β and Ki-67 expression levels, and higher IL-10 expression levels, with significant differences (P < 0.001). Compared with the RVH group, the EH group had a significantly higher proportion of CD4+CD25+Foxp3+ Treg cells, TGF-β and Ki-67 expression levels, and lower IL-10 expression levels, with significant differences (P < 0.001). Real-time quantitative PCR results showed that the RVH group also had significantly higher relative expression levels of Notch receptor Notch1 mRNA, Notch ligand DLL1, DLL4, Jagged1, and Jagged2 mRNA in PBMC than the NC group and EH group, with significant differences (P < 0.001). Western blot results showed that after adding Notch1 signaling pathway inhibitor (DAPT), Hes1 and Hes5 expression in peripheral CD4+CD25+Foxp3+ Treg cells of patients decreased significantly (P < 0.001), while CD4+CD25+Foxp3+ Treg proportion and TGF-β expression level increased significantly (P < 0.001). The Notch1 signaling pathway plays an immunoregulatory role in RVH regulated by CD4+CD25+Foxp3+ Treg cells. Regulation of the Notch1 signaling pathway can significantly promote the proliferation of CD4+CD25+Foxp3+ Treg cells and the ability to secrete anti-inflammatory factors.