Versatile roles of innate lymphoid cells at the mucosal barrier: from homeostasis to pathological inflammation

Abstract

Innate lymphoid cells (ILCs) are innate lymphocytes that do not express antigen-specific receptors and largely reside and self-renew in mucosal tissues. ILCs can be categorized into three groups (ILC1–3) based on the transcription factors that direct their functions and the cytokines they produce. Their signature transcription factors and cytokines closely mirror those of their Th1, Th2, and Th17 cell counterparts. Accumulating studies show that ILCs are involved in not only the pathogenesis of mucosal tissue diseases, especially respiratory diseases, and colitis, but also the resolution of such diseases. Here, we discuss recent advances regarding our understanding of the biology of ILCs in mucosal tissue health and disease. In addition, we describe the current research on the immune checkpoints by which other cells regulate ILC activities: for example, checkpoint molecules are potential new targets for therapies that aim to control ILCs in mucosal diseases. In addition, we review approved and clinically- trialed drugs and drugs in clinical trials that can target ILCs and therefore have therapeutic potential in ILC-mediated diseases. Finally, since ILCs also play important roles in mucosal tissue homeostasis, we explore the hitherto sparse research on cell therapy with regulatory ILCs. This review highlights various therapeutic approaches that could be used to treat ILC-mediated mucosal diseases and areas of research that could benefit from further investigation.

Amorphous silica nanoparticles and the human gut microbiota: a relationship with multiple implications

“…In addition to epithelial cells, the gastrointestinal mucosa contains an important and complex population of innate and adaptive immune cells, which must survey the 200 m 2 -mucosal surface and establish homeostatic relationships with the normal microbiota, while preventing and counteracting tissue invasion from pathogens or toxic substances. The population of innate immune cells comprises macrophages, dendritic cells, and innate lymphoid cells (ILCs), with a predominance of ILC3 cells, whereas adaptive cells include various subsets of T and B cells [ 56 , 57 ].…”