Saccharomyces boulardii produces in rat small intestine a novel protein phosphatase that inhibits Escherichia coli endotoxin by dephosphorylation.
Using a polyclonal antibody raised against a highly conserved sequence of 38 amino acids containing the activation site (VTDSAAGAT) common to mammalian and yeast alkaline phosphatases (AP), we identified in decapsidated Saccharomyces boulardii a protein phosphatase detected by autoradiography as a single signal (63 kD). Using an affinity chromatography column, the protein phosphatase could be concentrated 39.1-fold and presented as a doublet of two subunits. Compared with rat and bovine purified intestinal AP, the enzyme from S. boulardii had a greater ability to dephosphorylate the lipopolysaccharide (LPS) of Escherichia coli 055B5. When tested in vivo, intraperitoneal injection of intact LPS to rats produced, after 9 h, 100 ng/mL of circulating tumor necrosis factor-alpha with inflammatory lesions and apoptotic bodies in the liver and the heart, whereas rats injected with partially dephosphorylated LPS produced only 40 ng/mL tumor necrosis factor-alpha without organic lesions. In conclusion, S. boulardii is able to inhibit toxicity of E. coli surface endotoxins by the release of a protein phosphatase exhibiting a great capacity of dephosphorylation.
Buts
Jean-Paul
JP
Laboratory of Pediatric Gastroenterolgy and Nutrition, Université Catholic de Louvain, Brussels, Belgium. buts@gype.ucl.ac.be
Dekeyser
Nadine
N
Stilmant
Catherine
C
Delem
Emilie
E
Smets
Francoise
F
Sokal
Etienne
E
D000469:Alkaline Phosphatase / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D005260:Female; D007421:Intestine, Small / Q000201:enzymology* / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012440:Saccharomyces / Q000201:enzymology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D004731:Endotoxins; D014409:Tumor Necrosis Factor-alpha; C044101:endotoxin, Escherichia coli; D000469:Alkaline Phosphatase; D010749:Phosphoprotein Phosphatases