The effect of Afinitor (Everolimus) treatment on the expression of inhibitory immune checkpoint molecules in monocyte-derived dendritic cells

Abstract

The immune system consists of a complex network of anatomical barriers, chemical defenses, and cellular actors that include innate and acquired immunity. Dendritic cells (DCs) are unique professional antigen-presenting cells that play critical roles in the initiation and regulation of immune responses. Dendritic cells connect the innate and acquired arms of the immune system. Currently, DC modification is a new method for the treatment of several disorders. In autoimmune diseases, the excessive activation of the immune system causes the symptoms and form of the disease to become more severe, so investigating the immune system suppression strategies can be effective in the treatment of these diseases. Tolerogenic dendritic cells play an essential role in suppressing immune system responses through the production and expression of inhibitory factors, including inhibitory immune checkpoint molecules. Due to the intervention of Everolimus in different signaling pathways in cells especially the inhibition of mTOR signaling pathway and its modulating properties on the immune system, this study was conducted with the aim of investigating the effect of Everolimus treatment on the maturation and expression of immune checkpoint genes in monocyte-derived dendritic cells, so that if their expression increases and dendritic cells become tolerized, it can be used as a strategy in the immunotherapy of autoimmune diseases. Methods: To isolate monocytes from PBMCs, the CD14 marker was used via the MACS method. Monocytes were cultured and induced to differentiate into monocyte‐derived DCs by utilizing GM‐CSF and IL‐4 cytokines. On the fifth day, immature DCs were treated with Everolimus and incubated for 24 h. On the sixth day, the flow cytometry technique was used to investigate the effect of Everolimus on the phenotypic characteristics of DCs. In the end, the expression of immune checkpoint genes in both the Everolimus‐treated and untreated DCs groups was assessed using the real‐time PCR method. Results: The findings of this research demonstrated that the administration of Everolimus to DCs led to a notable rise in human leukocyte antigen (HLA)‐DR expression and a decrease in CD11c expression. Furthermore, there was a significant increase in the expression of immune checkpoint molecules, namely CTLA‐4, VISTA,PD-L , and BTLA in DCs treated with Everolimus.