Objective:To explore the expression and role of magnesium transporter 1(MagT1) in peripheral blood CD8+T lymphocytes of patients with sepsis. Methods:The data of 96 patients with sepsis treated in Dongguan Binhaiwan Central Hospital from March 2018 to May 2021 were collected. According to the degree of infection and circulatory failure, the patients were divided into common sepsis group(n=39), severe sepsis group(n=33) and septic shock group(n=24), and 30 healthy people from physical examination center were selected as control group during the same period. CD8+T cells from the peripheral blood of patients in each group were isolated and cultured, and the Mg2+ concentration in peripheral blood and CD8+T cells was detected. The expressions of variety of Mg2+ transporters(TRPM7, TRPM6, Mrs2p, SLC41A1, SLC41A2, MagT1 And ACDP2) mRNA in CD8+T cells were determined by qRT-PCR assay. The expression of MagT1 protein in CD8+T cells was detected by Western blot method. The expression levels of CD8+T cell surface inhibitory receptors PD-1, Tim-3 and activated receptors NKG2D, HLA-DR were detected by flow cytometry. Pearson correlation method was used to analyze the correlation between the MagT1 and the PD-1, Tim-3, NKG2D and HLA-DR expression levels. Results:Compared with the control group, the Mg2+ concentration in CD8+T cells of sepsis patients was significantly reduced(P<0.05), and the more severe the disease, the lower the concentration, while the Mg2+ concentration in peripheral blood had no significant difference(P>0.05). The expressions of MagT1 mRNA in CD8+T cells of sepsis patients were significantly reduced(P<0.05), but there was no significant difference in the mRNA expression of the other six Mg2+ transporters(P>0.05).The expression of MagT1 protein in CD8+T cells of sepsis patients was also markedly decreased(P<0.05), and the expressions of cell surface inhibitory molecules PD-1 and Tim-3 were significantly increased(P<0.05), while the expressions of activation molecules NKG2D and HLA-DR were significantly decreased(P<0.05). Pearson correlation analysis showed that MagT1 was significantly and negatively correlated with PD-1 and Tim-3, but was significantly and positively correlated with NKG2D and HLA-DR(P<0.05). Conclusion:MagT1 is low expressed in CD8+T cells in patients with sepsis, and it regulates the expression of CD8+T cell surface molecules by reducing the intracellular Mg2+ concentration, which leads to the depletion of CD8+T cells in patients with sepsis.
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