Effects of Notch1 signaling on regulatory T cells and coronary artery lesions in childhood Kawasaki disease / 中华风湿病学杂志

ABSTRACT

Objective:To explore the effect of Notch1 signaling on regulatory T cells and its roles in vascular damage in patients with Kawasaki disease (KD).Methods:A total of 42 children with KD were enrolled in the present study from March 2019 to June 2020, as 32 age-matched healthy children were recruited as control. The proportions of CD4 +CD25 hiFoxp 3+ regulatory T cells (Treg) and expressions of transcription factor forkhead box protein 3 (Foxp3), cytotoxic T lymphocyte associated antigen-4 (CTLA4), glucocorticoid-induced tumor necrosis factor receptor (GITR), and Notch1 protein were evaluated by flow cytometry. Chromatin immunoprecipitation was conducted to detect acetylation level of histone H4 (H4Ac) associated with the promoter of Foxp3 gene and its binding abilities of Notch1 intracellular domain 1 (NICD1), recombination signal binding protein for immunoglobulin kappa J region (RBP-J) and p300 in CD4 + T cells. Transcription levels of Foxp3, presenilin 1 (PSEN1), mastermind like transcriptional coactivator 1 (MAML1), and RBP-J in CD4 + T cells were determined by real-time polymerase chain reaction (PCR). Concentrations of interleukin (IL)-10 and transforming growth factor-β (TGF-β) in plasma and culture supernatant stimulated with Jagged1 were measured by enzyme linked immunosorbent assay. Independent-sample t-test, Pearson correlation analysis was used as the statistical method in this study. Results:① The frequencies of Treg in acute KD patients decreased significantly [(4.3±1.5)% vs (7.9±2.9)%; t=6.41, P<0.001], as protein levels of Foxp3, CTLA4 and GITR and concentrations of IL-10 and TGF-β in plasma reduced remarkably in acute KD patients ( t=6.87, P<0.001; t=4.26, P<0.001; t=7.88, P<0.001; t=8.42, P<0.001; t=13.01, P<0.001). All parameters afore-mentioned in patients combined with coronary artery lesions (CAL) were lower than those of patients without coronary artery lesions (NCAL) ( t=5.83, P<0.001; t=3.83, P<0.001; t=3.28, P=0.002; t=5.05, P<0.001; t=5.96, P<0.001; t=5.17, P<0.001), and increased after therapy ( t=7.13, P<0.001; t=6.10, P<0.001; t=4.31, P<0.001; t=6.55, P<0.001; t=7.40, P<0.001; t=7.84, P<0.001). ② H4Ac associated with promoter of Foxp3 gene and the binding abilities of NICD1 and p300 in acute KD patients were lower than those of the controls ( t=10.25, P<0.001; t=6.93, P<0.001; t=6.75, P<0.001), and increased remarkably after therapy ( t=7.72, P<0.001; t=4.16, P<0.001; t=5.76, P<0.001). Meanwhile, the three items in CAL group were found to be less than those of NCAL group ( t=6.08, P<0.001; t=2.66, P=0.011; t=6.02, P<0.001). Pearson correlation analysis showed a positive correlation between H4Ac associated with Foxp3 promoter and its mRNA level in acute KD patients ( r=0.47, P<0.001). No statistical significant difference about the binding ability of RBP-J with Foxp3 promoter were found among the groups ( t=0.57, P>0.05; t=0.61, P>0.05; t=1.20, P>0.05). ③ Protein level of Notch1 and the expressions of PSEN1, MAML1 and RBP-J mRNA in CD4 + T cells from acute KD patients were down-regulated remarkably ( t=5.28, P<0.001; t=6.31, P<0.001; t=11.78, P<0.001; t=8.06, P<0.001), and restored after therapy ( t=4.77, P<0.001; t=6.43, P<0.001; t=11.95, P<0.001; t=7.79, P<0.001). In parallel, the four indexes aforementioned of CAL group were lower than those of NCAL group ( t=3.16, P=0.003; t=4.13, P<0.001; t=5.42, P<0.001; t=4.05, P<0.001). Upon rhJagged1 stimulation for 48 hours, H4Ac level of Foxp3 promoter and its binding abilities with NICD1 and p300 in CD4 + T cells in KD patients and control group was significantly higher than those of untreated group [(KD t=15.36, P<0.001; t=7.25, P<0.001; t=14.29, P<0.001), (Ctrl t=7.87, P<0.001; t=5.71, P<0.001; t=8.74, P<0.001)], as the binding ability of RBP-J with Foxp3 promoter increased slightly without statistically significant difference (KD t=1.11, P>0.05; Ctrl t=1.37, P>0.05). Simultaneously, H4Ac level of Foxp3 promoter and its binding abilities with NICD1 and p300 in KD group were still lower than those of the control group after stimulation ( t=3.86, P<0.001; t=3.42, P=0.001; t=2.85, P=0.006). ④ After incubation of PBMC from heathy children with KD serum, the proportion of Treg cells, protein level of Foxp3 and expressions of Notch1 and RBP-J in CD4 + T cells in the group treated with IVIG increased significantly compared with the untreated group ( t=7.10, P<0.001; t=10.16, P<0.001; t=8.06, P<0.001; t=9.77, P<0.001), as well as H4Ac level of Foxp3 promoter and its binding abilities with NICD1 in the group treat with IVIG were also higher than the latter ( t=7.24, P<0.001; t=8.24, P<0.001). Conclusion:Insufficiency and impaired function of Treg caused by aberrant Notch1 signaling may be the important factor contributing to immune dysfunction and vascular damage in KD.