Evaluation of the cytotoxic activity of CD4+ T cells over oligodendrocytes in Multiple Sclerosis

Abstract

Multiple Sclerosis (MS) is an inflammatory and autoimune disease of the Central Nervous System (CNS). The cytotoxic activity of T lymphocytes has been reported as an effector mechanism for MS development. Moreover, it has been shown that the presence of cytotoxic CD4+ T cells (CD4_CTLs) drives MS progression and that these cells contribute to MS lesions by targeting oligodendrocytes. In this context, we demonstrated that CD4_CTLs alone induce apoptosis in healthy brain tissue in the experimental model. However, it is unclear if such cytotoxic activity is induced by the direct interaction of CD4_CTLs and oligodendrocytes or if these cells interact with local antigen-presenting cells releasing cytotoxic molecules in the CNS millieu. To resolve this uncertainty, we aim to evaluate the direct cytotoxic activity of CD4+ T cells over oligodendrocytes during MS. For that, Peripheral Blood Mononuclear Cells (PBMCs) isolated from Relapsing-Remitting MS patients (RRMS) and Healthy Controls (HC) will be reprogrammed into pluripotent stem cells (iPSCs) and then differentiated into Oligodendrocyte Precursor Cells (OPCs). Subsequently, the iPSC-derived OPCs will be co-cultured with CD4_CTLs previously sorted from the same patient/HC. The cultures will be treated with cytotoxic-related molecule inhibitors, and apoptosis induction will be assessed. Next, naive CD4+ T cells will be sorted from PBMCs of HC and differentiated into iCD4_CTLs. To assess the cytotoxic activity of the iCD4_CTLs, these cells will be co-cultured with the iPSC-derived OPCs in the presence of several cytotoxic-related molecule blockers, and assessed for apoptosis induction. Based on the proposed study, our goal is to elucidate the interaction between CD4_CTLs and oligodendrocytes during MS development, as well as to establish an in vitro model for differentiation and study of CD4_CTLs. (AU)