A tertiary amino-containing polymethacrylate polymer protects mucus-covered intestinal epithelial monolayers against pathogenic challenge.
OBJECTIVE
We examined the cytoprotective influences of the mucoadhesive polymer, poly(DMAEMA), on human mucus-producing intestinal epithelial monolayers against two bacterial exotoxins and S. typhimurium. Direct anti-bacterial effects were also assessed against S. typhimurium.


METHODS
In the presence and absence of mucus, untreated or poly(DMAEMA)-exposed monolayers were challenged with S. typhimurium or supernatants containing either cholera (CTx) or C. difficile toxins. Assays included LDH, cytokine secretion, cyclic AMP (cAMP) and microscopy to visualise bacterial adherence by monolayers. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of poly(DMAEMA) against S. typhimurium were established, along with a time-kill study.


RESULTS
CTx and C. difficile toxin induced LDH release from E12 monolayers. CTx also elevated intracellular epithelial cAMP, while S. typhimurium induced basolateral IL-8 secretion. Pre-treatment of E12 monolayers with poly(DMAEMA) reduced these effects, but only in the presence of mucus. The polymer co-localised with S. typhimurium in mucus and reduced bacteria-epithelia association. Poly(DMAEMA) was directly bactericidal against S. typhimurium at 1 mg/ml within 30 min.


CONCLUSIONS
Poly(DMAEMA) may have potential as a non-absorbed polymer therapeutic against infection. These effects were mediated by a combination of physical interaction with mucus and by direct bacterial killing.
School of Agriculture, Food Science and Veterinary Medicine and UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Simon
S
Keely
Lee-Anne B
LA
Rawlinson
David M
DM
Haddleton
David J
DJ
Brayden
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D002772:Cholera Toxin / Q000037:antagonists & inhibitors; D000242:Cyclic AMP / Q000378:metabolism; D005456:Fluorescent Dyes; D019073:HT29 Cells; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000382:microbiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009093:Mucus / Q000187:drug effects / Q000502:physiology*; D009757:Nylons / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D020011:Protective Agents / Q000737:chemistry / Q000494:pharmacology*; D012480:Salmonella Infections / Q000517:prevention & control; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development
D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D016209:Interleukin-8; D008689:Methacrylates; D009757:Nylons; D020011:Protective Agents; C109846:poly(2-(diethylamino)ethyl methacrylate); D002772:Cholera Toxin; D000242:Cyclic AMP; D007770:L-Lactate Dehydrogenase