Abstract:

Objective To discuss the differential expression of microRNA（miR）-125a-5p in peripheral blood mononuclear cells （PBMCs） of the patients with mycobacterium tuberculosis （MTB） infection and its effect on macrophage polarization， and to clarify its clinical significance. Methods A total of 40 patients with active tuberculosis （ATB） （ATB group）， 35 patients with latent tuberculosis infection （LTBI） （LTBI group）， and 40 healthy physical examinees （control group） clinically diagnosed from July 2022 to June 2023 were selected. The fasting blood samples of the subjects in three groups were collected next morning after 12 h of fasting， and then serum was separated. Enzyme-linked immunosorbent assay（ELISA） method was used to detect the levels of inflammatory factors in the serum of the subjects in various groups. Simultaneously， the PBMCs were extracted from the subjects in various groups； flow cytometry was used to detect the expression levels of CD80 and CD206 proteins in the PBMCs of the subjects in various groups； real-time fluorescence quantitative PCR （RT-qPCR） method was used to detect the expression levels of microRNA （miR）-125a-5p and interleukin-6 （IL-6） mRNA in PBMCs of the subjects in various groups. Results There were no statistically significant differences in the general information of the subjects among three groups （P>0.05）. Compared with control group， the erythrocyte sedimentation rate （ESR）， percentages of monocytes （MONO）， tumor necrosis factor-α （TNF-α） levels， and interleukin-10 （IL-10） levels in serum of the patients in ATB group and LTBI group were significantly increased （P<0.05）， and the percentages of lymphocytes （LY） were significantly decreased （P<0.05）； compared with ATB group， the ESR and level of IL-10 in serum of the patients in LTBI group were significantly decreased （P<0.05）， and the percentage of LY was significantly increased （P<0.05）； there were statistically significant differences in the counts of white blood cell （WBC） of the subjects among various groups （P>0.05）. The flow cytometry results showed that compared with control group， the expression levels of CD80 and CD206 proteins in PBMCs of the patients in ATB group and LTBI group were significantly increased （P<0.05）. Compared with ATB group， the expression level of CD206 protein in the PBMCs of the patients in LTBI group was significantly increased （P<0.05）， and the expression level of CD80 protein was significantly decreased （P<0.05）. The RT-qPCR results showed that compared with control group， the expression levels of miR-125a-5p and IL-6 mRNA in the PBMCs of the patients in ATB group and LTBI group were significantly increased （P<0.05）； compared with ATB group， the expression levels of miR-125a-5p and IL-6 mRNA in PBMCs of the patients in LTBI group were significantly increased （P<0.05）. The correlation analysis results showed that the miR-125a-5p expression level was positively correlated with the TNF-α level and IL-6 mRNA expression level （r=0.406， P<0.05； r=0.351， P<0.05）， and negatively correlated with the IL-10 level （r=-0.368， P<0.05）. The area under the receiver operating characteristic （ROC） curve （AUC） value of miR-125a-5p expression level for diagnosing LTBI patients was 0.89 （P<0.01）， with a sensitivity of 0.85 and a specificity of 0.88. Conclusion The expression level of miR-125a-5p in PBMCs of the patients in LTBI group is significantly increased， and it can affect the macrophage polarization to M1， promote the inflammatory response process of macrophages and participate in the occurrence and development of pulmonary tuberculosis.

Key words: Pulmonary tuberculosis, Latent tuberculosis infection, MicroRNA-125a-5p, Macrophage, Inflammatory response