Functions of Macrophages in the Maintenance of Intestinal Homeostasis

Figure 3

Mechanism of butyrate in modulating intestinal macrophage function. The microbial metabolite butyrate causes intestinal macrophages to reduce secretion of proinflammatory mediators such as IL-6, IL-12, and nitric oxide (NO) via inhibition of histone deacetylase (HDAC). This effect drives the intestinal immune system to be tolerant of commensals. Butyrate is also a strong inducer of host defense peptides (HDPs) that have pleiotropic functions in the maintenance of intestinal homeostasis, such as upregulation of tight junction protein expression in the intestinal epithelium, and clearance of pathogenic bacteria.