Macrophages in intestinal fibrosis and regression.

• Macrophages in the gut originate from the embryo and the circulation. • Gut macrophages can be anatomically classified into mucosal and muscularis subsets. • Macrophages function as multitaskers in the gut inflammation and fibrosis. • Anti-fibrotic macrophages regulate the regression of gut fibrosis. Intestinal macrophages are heterogenous cell populations with different developmental ontogeny and tissue anatomy. The concerted actions of intestinal macrophage subsets are critical to maintaining tissue homeostasis. However, the dysregulation of macrophages following tissue injury or chronic inflammation could also lead to intestinal fibrosis, with few treatment options in the clinic. In this review, we will characterize the features of intestinal macrophages in light of the latest advances in lineage tracing and single-cell sequencing technology. The roles of macrophages in distinct stages of intestinal fibrosis would be also elaborated. Finally, based on the reciprocal interaction between macrophages and intestinal fibrosis, we will propose the potential macrophage targeting anti-intestinal fibrosis therapies. [ABSTRACT FROM AUTHOR]