Regulatory mechanisms of the Notch pathway and Th1/Th2 cells during Mycobacterium tuberculosis infection
OBJECTIVE To investigate the regulatory mechanism of the Notch pathway and Th1/Th2 cells during Mycobacterium tuberculosis infection in patients with pulmonary tuberculosis.METHODS A total of 128 patients with tuberculosis admitted to Wuhan Jinyintan Hospital between May 2021 and Jan.2023 were selected as the dis-ease group,while 60 tuberculin test-negative patients diagnosed during the same period were chosen as the control group.Prior to treatment,fasting peripheral blood samples were collected from both groups,peripheral blood mononuclear cells(PBMCs)were isolated using human lymphocyte separation medium,the mRNA expressions of Notch1 and Jagged2 were quantified using real-time fluorescent quantitative PCR,and the Th1/Th2 cell ratio was determined by flow cytometry.The PBMCs isolated from the disease group were inoculated in 96-well plates,and different concentrations of y-secretase inhibitors(DAPT)(0,2.5,5.0,10.0 and 20.0 mol/L)were employed,Th1/Th2 cells were determined by flow cytometry,and protein expressions of Notch1 and Jagged2 in different DAPT concentration groups were determined via Western blot.RESULTS The Notch1 mRNA and Jagged2 mRNA in PBMCs of the disease group were 19.73±3.42 and 21.13±4.05,respectively,higher than those in the normal group(P＜0.05).The proportions of Th1 and Th2 in PBMCs of the disease group were(3.89±1.13)％and(3.99±1.28)％,which were higher than those of the normal group.The Th1/Th2 of the normal group was 0.97±0.28,which was lower than that of the disease group(P＜0.05).There was no significant difference in Th1 proportions among different DAPT concentration groups.As the concentration of DAPT increased,the pro-portion of Th2 gradually decreased and the Th1/Th2 ratio increased(P＜0.05).Furthermore,levels of Notch1 protein and Jagged2 protein decreased significantly(P＜0.05).CONCLUSIONS In patients with pulmonary tuber-culosis,Notch pathway proteins were abnormally highly expressed and the Th1/Th2 ratio was imbalanced.Down-regulation of Notch pathway expression by DAPT could antagonize Notch1 and Jagged2 protein expression and correct the Th1/Th2 ratio.
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