Microbiota—myeloid cell crosstalk beyond the gut

Abstract

The gut microbiota is a complex and dynamic microbial ecosystem that plays a fundamental role in host physiology. Locally, the gut commensal microbes/host symbiotic relationship is vital for barrier fortification, nutrient absorption, resistance against intestinal pathogens, and the development and maintenance of the mucosal immune system. It is now clear that the effects of the indigenous intestinal flora extend beyond the gut, ranging from shaping systemic immune responses to metabolic and behavioral functions. However, the underlying mechanisms of the gut microbiota/systemic immune system interactions remain largely unknown. Myeloid cells respond to microbial signals, including those derived from commensals, and initiate innate and adaptive immune responses. In this review, we focus on the impact of the gut microbiota on myeloid cells at extraintestinal sites. In particular, we discuss how commensal-derived signals affect steady-state myelopoiesis and cellular function and how that influences the response to infection and cancer therapy.

Intestinal Flora and Disease Mutually Shape the Regional Immune System in the Intestinal Tract

“…Many myeloid cells in the intestine, such as macrophages and dendritic cells, are activated by the intestinal flora to initiate innate and adaptive immunity, and inflammatory reactions (43). In addition, intestinal epithelial cells, as the first barrier of innate regional immunity, play an important role in activating the immune system and protecting the host from pathogens (44).…”

The role of the vaginal microbiome in gynaecological cancer

“…Chronic infection of S. enterica typhi in the gastrointestinal tract has been associated with pancreatic and lung cancer . More broadly, the gut microbiota appears to have systemic effects on the immune system . Several studies have reported systemic Th17 inflammation or anti‐inflammatory Treg activation due to the presence of commensal microbes of the gut .…”

The role of innate immunity in asthma development and protection: Lessons from the environment

“…SCFA binding to GPRs expressed on leucocytes, including neutrophils, eosinophils and macrophages, has been found to influence myelopoiesis and myelocyte migration . Intravascular recruitment of neutrophils induced by an LPS challenge was increased in Gpr43 −/− mice compared with wildtype mice .…”

“…111 SCFA binding to GPRs expressed on leucocytes, including neutrophils, eosinophils and macrophages, has been found to influence myelopoiesis and myelocyte migration. [112][113][114] Intravascular recruit-…”