Immune–stem cell crosstalk in the central nervous system: how oligodendrocyte progenitor cells interact with immune cells

Abstract

The interaction between immune and stem cells has proven essential for homeostasis and regeneration in a wide range of tissues. However, because the central nervous system was long considered an immune-privileged organ, its immune-stem cell axis was not deeply investigated until recently. Research has shown that oligodendrocyte progenitor cells (OPCs), a highly abundant population of adult brain stem cells, establish bidirectional interactions with the immune system. Here, we provide an overview of the interactions that OPCs have with tissue-resident and recruited immune cells, paying particular attention to the role they play in myelin regeneration and neuroinflammation. We highlight the described role of OPCs as key active players in neuroinflammation, overriding the previous concept that OPCs are mere recipients of immune signals. Understanding the mechanisms behind this bidirectional interaction holds great potential for the development of novel therapeutic approaches limiting neuroinflammation and promoting myelin repair. A better understanding of the central nervous system's immune-stem cell axis will also be key for tackling two important features shared across neurodegenerative diseases, neuroinflammation and myelin loss.

Oligodendrocyte precursor cells: the multitaskers in the brain

“…Bi-directional communication between OPCs and other immune cells has also been suggested by many studies [2,14,29]. The modulation of T cell responses by OPCs has primarily been studied in the context of multiple sclerosis (MS) (Fig.…”

“…1 G). In demyelinating lesions, OPCs release chemokines such as C-C motif ligand 2 (CCL2), CCL5 and CXCL10 to recruit T cells [ 44 ], and they activate T cells by expressing major histocompatibility complex (MHC) classes I and II, as well as antigens CD273 and CD274 (also known as programmed death ligand (PD-L)2 and PD-L1, respectively) [ 20 , 29 , 88 ] (reviewed by Cabeza-Fernández et al, [ 14 ]) (Fig. 1 G).…”

Unlocking the Potential: immune functions of oligodendrocyte precursor cells

“…OPCs also express antigens CD273 and CD274 (also known as programmed death ligand (PD-L) 2 and PD-L1, respectively) ( 24 , 27 , 43 ) (reviewed by Cabeza-Fernández et al ( 50 ), ). When exposed to cerebrospinal fluid (CSF) from MS patients in the phase of progressive MS (pMS), OPCs upregulate PD-L1, which in turn suppresses T cell-induced inflammation ( 43 ).…”