1. Optogenetic inhibition of the colon epithelium reduces hypersensitivity in a mouse model of inflammatory bowel disease
- Author
-
Brian S. Edwards, Kristen M. Smith-Edwards, Brian M. Davis, Sarah A. Najjar, Ariel Y Epouhe, Lindsay L Ejoh, Kathryn M. Albers, Emanuel Loeza-Alcocer, and Michael S. Gold
- Subjects
Colon ,Colon epithelium ,Pharmacology ,Optogenetics ,Inhibitory postsynaptic potential ,Inflammatory bowel disease ,Article ,Epithelium ,Mice ,03 medical and health sciences ,0302 clinical medicine ,030202 anesthesiology ,Animals ,Medicine ,Intestinal Mucosa ,business.industry ,Visceral pain ,Inflammatory Bowel Diseases ,medicine.disease ,Intestinal epithelium ,digestive system diseases ,Anesthesiology and Pain Medicine ,Nociception ,medicine.anatomical_structure ,Neurology ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Visceral pain is a prevalent symptom of inflammatory bowel disease (IBD) that can be difficult to treat. Pain and hypersensitivity are mediated by extrinsic primary afferent neurons (ExPANs) that innervate the colon. Recent studies indicate that the colon epithelium contributes to initiating ExPAN firing and nociceptive responses. Based on these findings we hypothesized that the epithelium contributes to inflammation-induced hypersensitivity. A key prediction of this hypothesis is that inhibition of the epithelium would attenuate nociceptive signaling and inflammatory hypersensitivity. To test this hypothesis, the inhibitory yellow light activated protein archaerhodopsin was targeted to the intestinal epithelium (villin-Arch) or the ExPANs (TRPV1-Arch) that innervate the colon. Visceral sensitivity was assessed by measuring the visceromotor response (VMR) to colorectal distension (CRD), with and without yellow light illumination of the colon lumen. Inhibition of the colon epithelium in healthy villin-Arch mice significantly diminished the CRD-induced VMR. Direct inhibition of ExPANs during CRD using TRPV1-Arch mice showed that ExPAN and epithelial inhibition were similarly effective in reducing the VMR to CRD. We then investigated the effect of epithelial and ExPAN inhibition in the dextran sulfate sodium (DSS) model of inflammatory bowel disease (IBD). Inhibition of the colon epithelium significantly decreased DSS-induced hypersensitivity and was comparable to inhibition of ExPANS. Together these results reveal the potential of targeting the colon epithelium for treatment of pain.
- Published
- 2020
- Full Text
- View/download PDF