CTLA-4-expressing ILC3s restrain interleukin-23-mediated inflammation.

Interleukin (IL-)23 is a major mediator and therapeutic target in chronic inflammatory diseases that also elicits tissue protection in the intestine at homeostasis or following acute infection. However, the mechanisms that shape these beneficial versus pathological outcomes remain poorly understood. To address this gap in knowledge, we performed single-cell RNA sequencing on all IL-23 receptor-expressing cells in the intestine and their acute response to IL-23, revealing a dominance of T cells and group 3 innate lymphoid cells (ILC3s).

ILC3s select microbiota-specific regulatory T cells to establish tolerance in the gut.

Microbial colonization of the mammalian intestine elicits inflammatory or tolerogenic T cell responses, but the mechanisms controlling these distinct outcomes remain poorly understood, and accumulating evidence indicates that aberrant immunity to intestinal microbiota is causally associated with infectious, inflammatory and malignant diseases. Here we define a critical pathway controlling the fate of inflammatory versus tolerogenic T cells that respond to the microbiota and express the transcription factor RORγt. We profiled all RORγt immune cells at single-cell resolution from the intestine-draining lymph nodes of mice and reveal a dominant presence of T regulatory (T) cells and lymphoid tissue inducer-like group 3 innate lymphoid cells (ILC3s), which co-localize at interfollicular regions.

ZBTB46 defines and regulates ILC3s that protect the intestine.

RORγt is a lineage-specifying transcription factor that is expressed by immune cells that are enriched in the gastrointestinal tract and promote immunity, inflammation and tissue homeostasis. However, fundamental questions remain with regard to the cellular heterogeneity among these cell types, the mechanisms that control protective versus inflammatory properties and their functional redundancy. Here we define all RORγt immune cells in the intestine at single-cell resolution and identify a subset of group 3 innate lymphoid cells (ILC3s) that expresses ZBTB46, a transcription factor specifying conventional dendritic cells.

Dendritic cell-derived hepcidin sequesters iron from the microbiota to promote mucosal healing.

Bleeding and altered iron distribution occur in multiple gastrointestinal diseases, but the importance and regulation of these changes remain unclear. We found that hepcidin, the master regulator of systemic iron homeostasis, is required for tissue repair in the mouse intestine after experimental damage. This effect was independent of hepatocyte-derived hepcidin or systemic iron levels.

Pulmonary Manifestations in Adolescents With Inflammatory Bowel Disease.

. The available literature on pulmonary disease in pediatric inflammatory bowel disease is limited. We evaluated the prevalence of pulmonary manifestations in pediatric inflammatory bowel disease and their association with disease severity.

Innate lymphoid cells support regulatory T cells in the intestine through interleukin-2.

Interleukin (IL)-2 is a pleiotropic cytokine that is necessary to prevent chronic inflammation in the gastrointestinal tract. The protective effects of IL-2 involve the generation, maintenance and function of regulatory T (T) cells, and the use of low doses of IL-2 has emerged as a potential therapeutic strategy for patients with inflammatory bowel disease. However, the cellular and molecular pathways that control the production of IL-2 in the context of intestinal health are undefined.