Vitamin D signal cascade in macrophages against <i>Mycobacterium tuberculosis</i>

Abstract

Mycobacterium tuberculosis is the causative agent of human tuberculosis; enabling multilayered mechanisms to evade from immune response along with reactivation of the process with subsequent pathogen dissemination. Modification of immune responses through imbalanced intracellular signaling pathways and reprogramming of differential gene expression is one of such mechanisms. Modification targets for M. tuberculosis are the genes which products are involved in lipid metabolism and apoptosis, a key to eliminate intracellular pathogens. here, we review the current scientific data related to this problem: the results of studies published in domestic and foreign literature from the years 2003 to 2022 were systematized and summarized; data on the role of a number of molecular mechanisms regulating lipid metabolism, autophagy and apoptosis in human TB-infection; discuss contemporary ideas about the importance of the VDR signaling cascade controlled by the vitamin D-axis counteracting M. tuberculosis infection, its course and outcome. In addition, there are provided the data on the main M. tuberculosis genetic lines common in Russia and Siberia and the elements of the pathogen-related genetic structure that are important in the context of the topic. The effects of interplay and interactions of intracellular molecular cascades (VDR, NF-kB, MAPK, NFAT5, AMPK, GR) are considered and analyzed, as well as their role in the differential expression of genes that ensure M. tuberculosis inactivation and elimination. Presenting the data confirming that one of the main strategies of mycobacterium immune evasion counteraction to autophagy and apoptosis is implemented through altered VDR signaling pathway, including the epigenetic mechanisms occurring in the pathogen. Based on results of the analysis and summarized literature data (60 articles retrieved from eLIBRARY, PubMed), it is demonstrated that during the thousand-year history of co-evolution with human, M. tuberculosis acquired unique features of genetic organization and mastered the pathways of immune evasion using non-genomic and genomic mechanisms. Available publications confirm that one of the main strategies for M. tuberculosis survival in macrophages is to modify a balance between intracellular signaling cascades controlling the differential expression of genes that provide a proper immune response to infection, followed by pathogen elimination.