Early Involvement of Peripherally Derived Monocytes in Inflammation in an NMO-Like Mouse Model [Monocytes]

Neuromyelitis optica (NMO) is an autoimmune inflammatory disease that primarily affects the spinal cord and optic nerves in the central nervous system (CNS). It is characterized by the presence of immunoglobulin G (IgG) antibodies against aquaporin 4, a protein found in astrocytes (known as NMO-IgG). Monocytes/macrophages and microglia accumulate at the active injury sites and contribute to the disease process. However, it is unclear whether these active cells originate from circulating monocytes/macrophages or resident microglia. Recent studies have investigated the role of microglia/macrophages in multiple sclerosis (MS) using specific microglial markers, such as P2ry12 and Tmem119, and have shown that active cells are derived from microglia. In contrast, the function of monocyte/macrophages and microglia in NMO has not been extensively studied. Therefore, this study aims to analyze the functions of monocytes/macrophages and microglia using microglial markers (P2ry12 and Tmem119) in an NMO-like mouse model and evaluate their role in the pathophysiology of NMO. Overall design: Cells were labeled with CD45, CD11b, P2ry12, Ly6C and Ly6G, and sorted CD45+CD11b+P2ry12-Ly6C+Ly6G- cells for monocytes