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Guo T, Patel S, Shah D, Chi L, Emadi S, Pierce DM, Han M, Brumovsky PR, Feng B. Optical clearing reveals TNBS-induced morphological changes of VGLUT2-positive nerve fibers in mouse colorectum. Am J Physiol Gastrointest Liver Physiol 2021; 320:G644-G657. [PMID: 33533318 PMCID: PMC8238166 DOI: 10.1152/ajpgi.00363.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/12/2021] [Accepted: 01/27/2021] [Indexed: 01/31/2023]
Abstract
Colorectal hypersensitivity and sensitization of both mechanosensitive and mechanically insensitive afferents develop after intracolonic instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in the mouse, a model of postinfectious irritable bowel syndrome. In mice in which ∼80% of extrinsic colorectal afferents were labeled genetically using the promotor for vesicular glutamate transporter type 2 (VGLUT2), we systematically quantified the morphology of VGLUT2-positive axons in mouse colorectum 7-28 days following intracolonic TNBS treatment. After removal, the colorectum was distended (20 mmHg), fixed with paraformaldehyde, and optically cleared to image VGLUT2-positive axons throughout the colorectal wall thickness. We conducted vector path tracing of individual axons to allow systematic quantification of nerve fiber density and shape. Abundant VGLUT2-positive nerve fibers were present in most layers of the colorectum, except the serosal and longitudinal muscular layers. A small percentage of VGLUT2-positive myenteric plexus neurons was also detected. Intracolonic TNBS treatment significantly reduced the number of VGLUT2-positive nerve fibers in submucosal, myenteric plexus, and mucosal layers at day 7 post-TNBS, which mostly recovered by day 28. We also found that almost all fibers in the submucosa were meandering and curvy, with ∼10% showing pronounced curviness (quantified by the linearity index). TNBS treatment resulted in a significant reduction of the proportions of pronounced curvy fibers in the rectal region at 28 days post-TNBS. Altogether, the present morphological study reveals profound changes in the distribution of VGLUT2-positive fibers in mouse colorectum undergoing TNBS-induced colitis and draws attention to curvy fibers in the submucosa with potential roles in visceral nociception.NEW & NOTEWORTHY We conducted genetic labeling and optical clearing to visualize extrinsic sensory nerve fibers in whole-mount colorectum, which revealed widespread presence of axons in the submucosal layer. Remarkably, axons in the submucosa were meandering and curvy, in contrast to axons in other layers generally aligned with the basal tissues. Intracolonic TNBS treatment led to pronounced changes of nerve fiber density and curviness, suggesting nerve fiber morphologies as potentially contributing factors to sensory sensitization.
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Affiliation(s)
- Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Shivam Patel
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
| | - Dhruv Shah
- Department of Molecular and Cell Biology, University of Connecticut, Mansfield, Connecticut
| | - Ling Chi
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
| | - Sharareh Emadi
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - David M Pierce
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
- Department of Mechanical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Martin Han
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
| | - Pablo R Brumovsky
- Instituto de Investigaciones en Medicina Traslacional, National Scientific and Technical Research Council, Austral University, Buenos Aires, Argentina
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, Mansfield, Connecticut
- Department of Physiology and Neurobiology, University of Connecticut, Mansfield, Connecticut
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Souza LKM, Nogueira KM, Araújo TSL, Sousa NA, Sousa FBM, Oliveira AP, Sales T, Silva K, Rocha TM, Leal LKAM, Magalhães PJC, Souza MHLP, Medeiros JVR. Anti-diarrheal therapeutic potential of diminazene aceturate stimulation of the ACE II/Ang-(1-7)/Mas receptor axis in mice: A trial study. Biochem Pharmacol 2021; 186:114500. [PMID: 33684388 DOI: 10.1016/j.bcp.2021.114500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/17/2021] [Accepted: 02/26/2021] [Indexed: 11/17/2022]
Abstract
The angiotensin (Ang) II converting enzyme (ACE II) pathway has recently been shown to be associated with several beneficial effects on the body, especially on the cardiac system and gastrointestinal tract. ACE II is responsible for converting Ang II into the active peptide Ang-(1-7), which in turn binds to a metabotropic receptor, the Mas receptor (MasR). Recent studies have demonstrated that Diminazene Aceturate (DIZE), a trypanosomicide used in animals, activates the ACE II pathway. In this study, we aimed to evaluate the antidiarrheal effects promoted by the administration of DIZE to activate the ACE II/Ang-(1-7)/MasR axis in induced diarrhea mice models. The results show that activation of the ACE II pathway exerts antidiarrheal effects that reduce total diarrheal stools and enteropooling. In addition, it increases Na+/K+-ATPase activity and reduces gastrointestinal transit and thus inhibits contractions of intestinal smooth muscle; decreases transepithelial electrical resistance, epithelial permeability, PGE2-induced diarrhea, and proinflammatory cytokines; and increases anti-inflammatory cytokines. Enzyme-linked immunosorbent assay (ELISA) demonstrated that DIZE, when activating the ACE II/Ang-(1-7)/MasR axis, can still interact with GM1 receptors, which reduces cholera toxin-induced diarrhea. Therefore, activation of the ACE II/Ang-(1-7)/MasR axis can be an important pharmacological target for the treatment of diarrheal diseases.
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Affiliation(s)
- Luan K M Souza
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil.
| | - Kerolayne M Nogueira
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Thiago S L Araújo
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil
| | - Nayara A Sousa
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil
| | - Francisca B M Sousa
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil
| | - Ana P Oliveira
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil
| | - Thiago Sales
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Karine Silva
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Talita M Rocha
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Luzia K A M Leal
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Pedro J C Magalhães
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Marcellus H L P Souza
- Department of Physiology and Pharmacology, Federal University of Ceará, Fortaleza, CE 60430-275, Brazil
| | - Jand V R Medeiros
- The Northeast Biotechnology Network (RENORBIO), Federal University of Piauí, Teresina, PI 64049-550, Brazil; Laboratory of Pharmacology of Inflammation and Gastrointestinal Disorders (Lafidg), Federal University of Parnaíba Delta (UFDPar), Av. São Sebastião, n° 2819, CEP 64202-02 Parnaíba, PI, Brazil; Biotechnology and Biodiversity Center Research, BIOTEC, Federal University of Parnaíba Delta, Parnaíba, PI 64202-020, Brazil
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