Background and purpose: ET-1 signaling modulates intestinal motility and inflammation, but the role of ET-1/ETBR signaling is poorly understood. Enteric glia modulate normal motility and inflammation. We investigated whether glial ETBR signaling is a mechanism regulating neural-motor pathways of intestinal motility and inflammation. Experimental approach: We studied ETBR signaling using: ETBR drugs (ET-1, SaTX, BQ788), activity-dependent stimulation of neurons (high K+ -depolarization, EFS), gliotoxins, Tg (Ednrb-EGFP) EP59Gsat/Mmucd mice, cell-specific mRNA in Sox10CreERT2; Rpl22-HAflx or ChATCre; Rpl22-HAflx mice, Sox10CreERT2 ::GCaMP5g-tdT, Wnt1Cre2 ::GCaMP5g-tdT mice, muscle tension recordings, fluid-induced peristalsis, ET-1 expression, qPCR, western blots, 3-D LSM-immunofluorescence co-labeling studies in LMMP-CM and a POI model of intestinal inflammation (P<0.01 is significant). Key results: In the muscularis externa ETBR is expressed exclusively in glia. ET-1 is expressed in RiboTag (ChAT)-neurons, isolated ganglia and intra-ganglionic varicose-nerve fibers co-labeled with peripherin or SP. Pharmacological analysis of neural evoked glial responses indicates that ET-1 release provides activity-dependent glial ETBR modulation of Ca2+ waves. BQ788 reveals amplification of glial and neuronal Ca2+ responses and excitatory cholinergic contractions. The BQ788 effect is sensitive to L-NAME. Gliotoxins disrupt SaTX-induced glial-Ca2+ waves and prevent BQ788 amplification of contractions. ETBR is linked to inhibition of contractions and peristalsis. Inflammation causes glial ETBR upregulation, SaTX-hypersensitivity and glial amplification of ETBR signaling. In vivo BQ788 (i.p.,1mg/Kg) attenuates intestinal inflammation in POI. Conclusion and implications: Enteric glial ET-1/ETBR signaling provides dual modulation of neural-motor circuits to inhibit motility - It inhibits excitatory cholinergic neural-motor pathways and stimulates inhibitory nitrergic motor pathways. Amplification of glial ETBR is linked to muscularis externa inflammation and possibly pathogenic mechanisms of postoperative ileus.
BQ788 Reveals Glial ETBR Modulation of Neuronal Cholinergic and Nitrergic Pathways to Inhibit Intestinal Motility: ETBR Signaling is Linked to POI / Mazzotta, E; Grants, I; Villalobos-Hernandez, E; Chaudhuri, S; Mcclain, J L; Seguella, L; Kendig, D M; Blakeney, B A; Murthy, K S; Schneider, Reiner; Leven, Patrick; Wehner, Sven; Harzman, A; Grider, J R; Gulbransen, B D; Christofi, F L. - In: BRITISH JOURNAL OF PHARMACOLOGY. - ISSN 0007-1188. - (2023). [10.1111/bph.16145]
BQ788 Reveals Glial ETBR Modulation of Neuronal Cholinergic and Nitrergic Pathways to Inhibit Intestinal Motility: ETBR Signaling is Linked to POI
Seguella, L;
2023
Abstract
Background and purpose: ET-1 signaling modulates intestinal motility and inflammation, but the role of ET-1/ETBR signaling is poorly understood. Enteric glia modulate normal motility and inflammation. We investigated whether glial ETBR signaling is a mechanism regulating neural-motor pathways of intestinal motility and inflammation. Experimental approach: We studied ETBR signaling using: ETBR drugs (ET-1, SaTX, BQ788), activity-dependent stimulation of neurons (high K+ -depolarization, EFS), gliotoxins, Tg (Ednrb-EGFP) EP59Gsat/Mmucd mice, cell-specific mRNA in Sox10CreERT2; Rpl22-HAflx or ChATCre; Rpl22-HAflx mice, Sox10CreERT2 ::GCaMP5g-tdT, Wnt1Cre2 ::GCaMP5g-tdT mice, muscle tension recordings, fluid-induced peristalsis, ET-1 expression, qPCR, western blots, 3-D LSM-immunofluorescence co-labeling studies in LMMP-CM and a POI model of intestinal inflammation (P<0.01 is significant). Key results: In the muscularis externa ETBR is expressed exclusively in glia. ET-1 is expressed in RiboTag (ChAT)-neurons, isolated ganglia and intra-ganglionic varicose-nerve fibers co-labeled with peripherin or SP. Pharmacological analysis of neural evoked glial responses indicates that ET-1 release provides activity-dependent glial ETBR modulation of Ca2+ waves. BQ788 reveals amplification of glial and neuronal Ca2+ responses and excitatory cholinergic contractions. The BQ788 effect is sensitive to L-NAME. Gliotoxins disrupt SaTX-induced glial-Ca2+ waves and prevent BQ788 amplification of contractions. ETBR is linked to inhibition of contractions and peristalsis. Inflammation causes glial ETBR upregulation, SaTX-hypersensitivity and glial amplification of ETBR signaling. In vivo BQ788 (i.p.,1mg/Kg) attenuates intestinal inflammation in POI. Conclusion and implications: Enteric glial ET-1/ETBR signaling provides dual modulation of neural-motor circuits to inhibit motility - It inhibits excitatory cholinergic neural-motor pathways and stimulates inhibitory nitrergic motor pathways. Amplification of glial ETBR is linked to muscularis externa inflammation and possibly pathogenic mechanisms of postoperative ileus.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
