Non‐zero‐sum microbiome immune system interactions

Abstract

Fundamental asymmetries between the host and its microbiome in enzymatic activities and nutrient storage capabilities have promoted mutualistic adaptations on both sides. As a result, the enteric immune system has evolved so as not to cause a zero-sum sterilization of non-self, but rather achieve a non-zero-sum self-reinforcing cooperation with its evolutionary partner the microbiome. In this review, we attempt to integrate the accumulated knowledge of immune-microbiome interactions into an evolutionary framework and trace the pattern of positive immune-microbiome feedback loops across epithelial, enteric nervous system, innate, and adaptive immune circuits. Indeed, the immune system requires commensal signals for its development and function, and reciprocally protects the microbiome from nutrient shortage and pathogen outgrowth. In turn, a healthy microbiome is the result of immune system curatorship as well as microbial ecology. The paradigms of host-microbiome asymmetry and the cooperative nature of their interactions identified in the gut are applicable across all tissues influenced by microbial activities. Incorporation of immune system influences into models of microbiome ecology will be a step forward toward defining what constitutes a healthy human microbiome and guide discoveries of novel host-microbiome mutualistic adaptations that may be harnessed for the promotion of human health.

Diet-mediated constitutive induction of novel IL-4+ ILC2 cells maintains intestinal homeostasis in mice

“…The development and function of colonic innate and adaptive immune cell populations are strongly influenced by the presence of the microbiota ( Gury-BenAri et al, 2016 ; Honda and Littman, 2016 ; Tuganbaev and Honda, 2021 ). However, the frequency of colonic IL-4 + ILC2s and their transcriptional profiles were not affected by the absence of the microbiota.…”

Role of GDNF, GFRα1 and GFAP in a Bifidobacterium-Intervention Induced Mouse Model of Intestinal Neuronal Dysplasia

“…Gut microbiome can affect the function and number of enteric neurons (8)(9)(10), and the early gut microbiota plays an important role in the development of the ENS after birth (11,12). Several studies have shown that abnormalities in the myenteric plexus and a decrease of intestinal motility can be observed in early postnatal germ-free mice (11).…”