Loading…
Eubiosis / Homeostasis is a balanced gut microbiota state where diverse microbial communities interact harmoniously to support the host’s health
During eubiosis, intestinal epithelial cells (IECs) secrete mucins, antimicrobial peptides (AMPs), and cytokines. The cytokines promote the development of tolerogenic dendritic cells (DCs) and macrophages
A balanced, eubiotic intestinal microbiota forms sufficient amounts of short-chain fatty acids (SCFAs ). Bacteria belonging to the phylum Firmicutes / Bacillota are known SCFAs producers. The SCFAs influence Intestinal immune system in the lamina propria . As shown here using the example of the mesenteric lymph node (MLN), the SCFAs, in addition to other modulatory effects on lymphocytes , up-regulate the anti-inflammatory Treg cells and down-regulate the migration of neutrophils . As a result, pro -and Anti-inflammatory cytokines are balanced in both the systemic circulation and the spleen , which has an average weight. In addition, SCFAs reduce the intracellular formation of ROS . The reduction in intracellular ROS induced by SCFAs leads to reduced activation of NFKB signaling and reduced induction of cellular DNA damage
Epithelial barriers and specific regulatory proteins such as immunoglobulin A (IgA) and Regenerating Islet-Derived Protein 3 Gamma / Regenerating Islet-Derived Protein III-Gamma (REG3G) are crucial in maintaining eubiosis.
The balance of Th17 and Treg cells , which are characterized by pro-inflammatory and anti-inflammatory cytokines, is critical for the host’s intestinal homeostasis and is directly affected by the normal gut microbiota content
The homeostasis in the gut is formed by nutrition, metabolite uptake, mucosal barrier maintenance, mucosal immune regulation
During homeostasis, TH17 cells and ILC3 are induced by certain species of the commensal microbiota. IL-17A and IL-22 promote epithelial barrier integrity, mucus production, and the release of anti-microbial peptides
Gut Epithelial Homeostasis Is Maintained by Continuous Crosstalk between the Gut Microbiota, Immune Cells and the Mucosal Barrier
Roy & Trinchieri 2017
Central to this homeostatic relationship is immunoglobulin A (IgA) production
Under normal physiological conditions, Gut microbiota acts as a homeostatic organ involved in the fermentation of complex undigested polysaccharide polymers, production of short-chain fatty acids (SCFAs), synthesis of certain vitamins, energy production, intestinal mucosa integrity, and preclusion of pathogenic microbes
Wu et al. 2016a Inflamm. Bowel Dis. 22: 1473-1482
A generally accepted definition of what constitutes a healthy gut microbiota does not yet exist. However, there are some key criteria that are commonly associated with healthy Gut microbiota: high overall microbial diversity, stability, and redundancy of major functions
Functions of a healthy microbiota: digestion, (generation of SCFA), metabolism of xenobiotics, colonization resistance
Gut tissue must integrate commensal bacteria and maintain their numbers and composition without inducing inflammatory tissue damage
Certain symbiotic Gut microbiota members have been reported to have distinct and specific effects on the host immune system, and are considered key to immune homeostasis
see also:
Colonization resistance
Good guys (certain beneficial bacteria)
Gut microbiota & Health
Intestinal Homeostasis