S. Typhimurium challenge in juvenile pigs modulates the expression and localization of enteric cholinergic proteins and correlates with mucosal injury and inflammation

Salmonella Typhimurium challenge and invasion triggers immune cell recruitment, inflammation and mucosal injury including epithelial cell loss. Subsequent reduction in acetylcholine (ACh) concentrations in the mucosa may induce a compensatory response to preserve and (or) amplify cholinergic signaling by (1) upregulating ACh synthesis via choline acetyltransferase (ChAT) in epithelial cells, lamina propria monocytes and enteric neurons (not shown) (2) down-regulating ACh degradation via suppression of acetylcholinesterase (AChE), and (3) enhancing of ACh signaling via increased expression of muscarinic M1 and M3 cholinergic receptors. Dotted lines indicate hypothesized mechanisms by which mucosal damage and inflammation may drive altered cholinergic expression.175