Polysaccharide A

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Polysaccharide A (PSA) is a polysaccharide produced by the Gram-negative bacterium Bacteroides fragilis . [1] B.fragilis produces eight identified distinct capsular polysaccharides, identified by the letters "A" through "H". [2]

PSA interacts with Toll-like receptor 2 (TLR2) on dendritic cells. [3] PSA colonization of B. fragilis in the gut mucosa induces regulatory T cells and suppresses pro-inflammatory T helper 17 cells. [2] PSA has been shown to protect animals from experimental diseases like colitis, asthma, or pulmonary inflammation. [2] Nonetheless, PSA can be pro-inflammatory as well as anti-inflammatory. [4]

PSA has been studied extensively in the spleen and gastrointestinal tract, but PSA uses regulatory T cells to reduce inflammation in the central nervous system. [3]

References

  1. Sun F, Zhang Q, Chen W (2019). "A potential species of next-generation probiotics? The dark and light sides of Bacteroides fragilis in health". Food Research International . 126: 108590. doi:10.1016/j.foodres.2019.108590. PMID   31732047. S2CID   201203450.
  2. 1 2 3 Erturk-Hasdemir D, Ochoa-Repáraz J, Kasper DL, Kasper LH (2021). "Exploring the Gut-Brain Axis for the Control of CNS Inflammatory Demyelination: Immunomodulation by Bacteroides fragilis' Polysaccharide A". Frontiers in Immunology . 12: 662807. doi: 10.3389/fimmu.2021.662807 . PMC   8131524 . PMID   34025663.
  3. 1 2 Rooks MG, Garrett WS (2016). "Gut microbiota, metabolites and host immunity". Nature Reviews Immunology . 16 (6): 341–352. doi: 10.1038/nri.2016.42 . PMC   5541232 . PMID   27231050.
  4. Alvarez CA, Jones MB, Hambor J, Cobb BA (2020). "Characterization of Polysaccharide A Response Reveals Interferon Responsive Gene Signature and Immunomodulatory Marker Expression". Frontiers in Immunology . 11: 556813. doi: 10.3389/fimmu.2020.556813 . PMC   7649347 . PMID   33193325.