Ji. Gordon et al., EPITHELIAL-CELL GROWTH AND DIFFERENTIATION .3. PROMOTING DIVERSITY INTHE INTESTINE - CONVERSATIONS BETWEEN THE MICROFLORA, EPITHELIUM, ANDDIFFUSE GALT, American journal of physiology: Gastrointestinal and liver physiology, 36(3), 1997, pp. 565-570
Homeostasis in the self-renewing mouse intestinal epithelium appears t
o be regulated in large part by cell nonautonomous mechanisms. The soc
iety of nonpathogenic bacteria that resides in the intestine is an imp
ortant source of instructions that modify epithelial differentiation p
rograms. The stability of this society is remarkable given its numeric
al, compositional, and spatial complexity, the openness of the ecosyst
em, and the fact that the epithelium is replaced so rapidly. The abili
ty of components of this society to influence epithelial differentiati
on may represent a critical step in allowing specific groups of organi
sms to be assembled in specific regions of the gut. Simplified model s
ystems have been created to define and dissect the conversations betwe
en microbe and host. These systems use inbred strains of mice that are
raised under germ-free conditions and then monocontaminated with a si
ngle component of the microflora. The results suggest that a trialogue
involving communications between the microflora, the epithelium, and
the diffuse gut-associated lymphoid tissue (GALT) may play a key role
in establishing and maintaining the spatial diversity of this remarkab
le ecosystem.