Background: MicroRNA-132 (miR-132) targets acetylcholinesterase (AChE) and potentiates the cholinergic blockade of inflammatory reactions in cultured cells and experimental mice, but the implications of this interaction to human inflammatory disease remained unexplored. This study aimed to test whether miR-132 is causally involved in anti-inflammatory reactions of patients with inflammatory bowel disease (IBD) and modulates vagal tone and consequently inflammation in patients with IBD.
Methods: We prospectively measured inflammation readouts and the cholinergic status (total capacity for hydrolyzing acetylcholine in one's circulation), and AChE activity in 2 independent cohorts of patients with IBD and quantified miR-132 levels in intestinal tissue biopsies removed at colonoscopy from inflamed and apparently quiescent tissues of tested volunteers.
Results: MiR-132 levels are higher in inflamed compared with apparently quiescent intestinal biopsies from patients with IBD. Correspondingly, the cholinergic status and AChE activity was significantly lower in patients with IBD suffering from moderate-severe disease as compared with healthy controls or patient with IBD presenting low disease severity. Patients with IBD (n = 16) presented lower AChE activity compared with healthy controls (n = 33; 289 ± 128 AU versus 391 ± 102 AU, P = 0.001), and a negative correlation between AChE activity and C-reactive protein levels (r = -0.47, P = 0.01). Corroborating these observations in an additional cohort of participants, C-reactive protein and AChE activity were negatively correlated in patients with moderate-severe disease (n = 16; r = -0.6, P = 0.04) and positively correlated in healthy controls (n = 74, r = 0.24, P = 0.046).
Conclusions: Taken together, these findings support an inflammation-dependent homeostatic role for the regulation by miR-132 of AChE in IBD, opening new venues for therapeutic interference.