Steroid immune responsive gene regulation in Mycobacterium tuberculosis infection in vitro

Tuberculosis (TB) is an infectious disease displaying a multifactorial pathology. The immunomodulatory role attributed to steroid hormones, such as vitamin D-3 (VD3) and 17 beta-estradiol (E-2), highlighted the importance of these hormones against Mycobacterium tuberculosis (Mtb) infection. In order to understand their influence upon gene expression of immune and inflammatory responsive genes against Mtb we tested it in vitro using peripheral blood mononuclear cells (PBMCs). Cells were pretreated with VD3 (50 ng/mL) or E-2 (100 nM/mL) and co-cultured with H37Rv Mtb or stimulated with lipopolysaccharide from Escherichia coli (LPS). After 24 h and 72 h of co-culture the Mtb viability in macrophages test was performed, as well the total RNA isolation for gene expression analysis by RT-qPCR of the following target genes: NLRP3, DC-SIGN, IL-1 beta, and IL-10. We also measured IL-10, TNF, IFN-gamma, IL-4, IL-6, and IL-2 supernatant levels. As the main results, we found that VD3 and E-2 downregulated the expression of inflammatory genes NLRP3, IL-1 beta, and IL-10 expression in Mtb co-cultured cells. Finally, VD3 treatment increased the release of the cytokine IFN-gamma in Mtb-infected cells, while E-2 treatment inhibited the release of IL-10, TNF, IFN-gamma, and IL-6. Therefore, we report an immunogenetic influence of VD3 and E-2 upon Mtb co-culture.