Figure 2.

The possible mechanism of MSCs in the treatment of TB. MSCs may achieve the purpose of treating TB by regulating the inflammatory response of TB, alleviating the lung injury of TB, affecting the survival of host cells and clearing bacteria. (A) The functions of innate immune cells and adaptive immune cells can be effectively regulated by MSCs through “direct interaction between cells”, secreting enzymes and cytokines. (B) EVs secreted by MSCs are lipid vesicles that mediate intercellular communication. (C) EVs can be used as antigen to bind to the target cells, or as a carrier to deliver proteins, DNA, mRNA and non-coding RNA to the target cells. (D) The function of immune cells can be regulated by MSCs through the release of EVs. (E) Macrophages can differentiate into foam cells, which are characterized by lipid accumulation. And MSCs can affect the lipid homeostasis of macrophages, inhibit the formation of foam cells, and reduce the expression of MHCII in macrophages, thereby reducing the uptake of oxidized low density lipoprotein. (F) KGF and HGF secreted by MSCs protect alveolar epithelial cell from apoptosis under hypoxic conditions. (G) MSCs can enhance pulmonary microvascular endothelial cell autophagy through PI3K/Akt signal transduction. (H) MSCs exhibited antimicrobial activity by secreting antimicrobial peptides and NO, enhancing the activity of lipoprotein-2, and enhanced autophagy.