Exploring the Impact of Leishmania Major on Mesenchymal Stem Cells: Evaluating Differentiation, and Immunomodulatory Function

Abstract

Pathogen recognition receptors (PRRs), which play a crucial role in responding to pathogens, affect the function of mesenchymal stem cells (MSCs). One important group of PRRs is the toll-like receptors (TLRs). When PRRs are activated, they can alter the expression of specific surface markers, the ability of MSCs to differentiate, and the types of substances they secrete. These modifications in MSC function may have unexpected consequences for patients. In this study, we examined how Leishmania major (L. major) promastigotes affect the properties of MSCs.
 MSCs were isolated from adipose tissue and categorized into two groups: one group left untreated and the other group exposed to L. major. Giemsa staining was employed to accurately quantify the number of parasites that entered the cells. After 72 hours, real-time polymerase chain reaction was utilized to assess the expression of TLRs. Additionally, the flow cytometry technique was used to evaluate the expression of surface markers on the MSCs.
 Our results showed that MSCs can engulf parasites and increase the expression of TLR4 and TLR6. The pro-inflammatory cytokine increased, and the transforming growth factor-β decreased significantly. The parasite exposure increased reactive oxygen species production. Additionally, the percentage of cluster differentiation (CD) 73 decreased, and the mean fluorescent index of CD29 and CD73 was down-regulated by L. major.
 Exposure to parasites diminishes the immunomodulatory capacity of MSCs. This discovery holds significance for the application of MSCs in addressing parasite infections and underscores the need for additional research to enhance their therapeutic effectiveness.