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Woods C, Flockton AR, Belkind-Gerson J. Phosphatase and Tensin Homolog Inhibition in Proteolipid Protein 1-Expressing Cells Stimulates Neurogenesis and Gliogenesis in the Postnatal Enteric Nervous System. Biomolecules 2024; 14:346. [PMID: 38540765 PMCID: PMC10967813 DOI: 10.3390/biom14030346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
Phosphatase and tensin homolog (Pten) is a key regulator of cell proliferation and a potential target to stimulate postnatal enteric neuro- and/or gliogenesis. To investigate this, we generated two tamoxifen-inducible Cre recombinase murine models in which Pten was conditionally ablated, (1) in glia (Plp1-expressing cells) and (2) in neurons (Calb2-expressing cells). Tamoxifen-treated adult (7-12 weeks of age; n = 4-15) mice were given DSS to induce colitis, EdU to monitor cell proliferation, and were evaluated at two timepoints: (1) early (3-4 days post-DSS) and (2) late (3-4 weeks post-DSS). We investigated gut motility and evaluated the enteric nervous system. Pten inhibition in Plp1-expressing cells elicited gliogenesis at baseline and post-DSS (early and late) in the colon, and neurogenesis post-DSS late in the proximal colon. They also exhibited an increased frequency of colonic migrating motor complexes (CMMC) and slower whole gut transit times. Pten inhibition in Calb2-expressing cells did not induce enteric neuro- or gliogenesis, and no alterations were detected in CMMC or whole gut transit times when compared to the control at baseline or post-DSS (early and late). Our results merit further research into Pten modulation where increased glia and/or slower intestinal transit times are desired (e.g., short-bowel syndrome and rapid-transit disorders).
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Affiliation(s)
- Crystal Woods
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, University of Colorado, Aurora, CO 80045, USA; (C.W.); (A.R.F.)
| | - Amanda R. Flockton
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, University of Colorado, Aurora, CO 80045, USA; (C.W.); (A.R.F.)
| | - Jaime Belkind-Gerson
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, University of Colorado, Aurora, CO 80045, USA; (C.W.); (A.R.F.)
- Neurogastroenterology and Motility Program, Digestive Health Institute, Children’s Hospital Colorado, Aurora, CO 80045, USA
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Gomez-Frittelli J, Hamnett R, Kaltschmidt JA. Comparison of wholemount dissection methods for neuronal subtype marker expression in the mouse myenteric plexus. Neurogastroenterol Motil 2024; 36:e14693. [PMID: 37882149 PMCID: PMC10842488 DOI: 10.1111/nmo.14693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/05/2023] [Accepted: 10/10/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Accurately reporting the identity and representation of enteric nervous system (ENS) neuronal subtypes along the length of the gastrointestinal (GI) tract is critical to advancing our understanding of ENS control of GI function. Reports of varying proportions of subtype marker expression have employed different dissection techniques to achieve wholemount muscularis preparations of myenteric plexus. In this study, we asked whether differences in GI dissection methods could introduce variability into the quantification of marker expression. METHODS We compared three commonly used methods of ENS wholemount dissection: two flat-sheet preparations that differed in the order of microdissection and fixation and a third rod-mounted peeling technique. We also tested a reversed orientation variation of flat-sheet peeling, two step-by-step variations of the rod peeling technique, and whole-gut fixation as a tube. We assessed marker expression using immunohistochemistry, genetic reporter lines, confocal microscopy, and automated image analysis. KEY RESULTS AND CONCLUSIONS We found no significant differences between the two flat-sheet preparation methods in the expression of calretinin or neuronal nitric oxide synthase (nNOS) as a proportion of total neurons in ileum myenteric plexus. However, the rod-mounted peeling method resulted in decreased proportion of neurons labeled for both calretinin and nNOS. This method also resulted in decreased transgenic reporter fluorescent protein (tdTomato) for substance P in distal colon and choline acetyltransferase (ChAT) in both ileum and distal colon. These results suggest that labeling among some markers, both native protein and transgenic fluorescent reporters, is decreased by the rod-mounted mechanical method of peeling. The step-by-step variations of this method point to mechanical manipulation of the tissue as the likely cause of decreased labeling. Our study thereby demonstrates a critical variability in wholemount muscularis dissection methods.
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Affiliation(s)
- Julieta Gomez-Frittelli
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305 USA
| | - Ryan Hamnett
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305 USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Julia A. Kaltschmidt
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305 USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305 USA
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Robinson BG, Oster BA, Robertson K, Kaltschmidt JA. Loss of ASD-related molecule Cntnap2 affects colonic motility in mice. Front Neurosci 2023; 17:1287057. [PMID: 38027494 PMCID: PMC10665486 DOI: 10.3389/fnins.2023.1287057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023] Open
Abstract
Gastrointestinal (GI) symptoms are highly prevalent among individuals with autism spectrum disorder (ASD), but the molecular link between ASD and GI dysfunction remains poorly understood. The enteric nervous system (ENS) is critical for normal GI motility and has been shown to be altered in mouse models of ASD and other neurological disorders. Contactin-associated protein-like 2 (Cntnap2) is an ASD-related synaptic cell-adhesion molecule important for sensory processing. In this study, we examine the role of Cntnap2 in GI motility by characterizing Cntnap2's expression in the ENS and assessing GI function in Cntnap2 mutant mice. We find Cntnap2 expression predominately in enteric sensory neurons. We further assess in vivo and ex vivo GI motility in Cntnap2 mutants and show altered transit time and colonic motility patterns. The overall organization of the ENS appears undisturbed. Our results suggest that Cntnap2 plays a role in GI function and may provide a molecular link between ASD and GI dysfunction.
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Affiliation(s)
- Beatriz G. Robinson
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, United States
- Neurosciences IDP Graduate Program, Stanford University School of Medicine, Stanford, CA, United States
| | - Beau A. Oster
- Nevada ENDURE Program, University of Nevada, Reno, Reno, NV, United States
| | - Keiramarie Robertson
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, United States
- Neurosciences IDP Graduate Program, Stanford University School of Medicine, Stanford, CA, United States
| | - Julia A. Kaltschmidt
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, United States
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, United States
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Robinson BG, Oster BA, Robertson K, Kaltschmidt JA. Loss of ASD-Related Molecule Cntnap2 Affects Colonic Motility in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537221. [PMID: 37131706 PMCID: PMC10153124 DOI: 10.1101/2023.04.17.537221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Gastrointestinal (GI) symptoms are highly prevalent among individuals with autism spectrum disorder (ASD), but the molecular link between ASD and GI dysfunction remains poorly understood. The enteric nervous system (ENS) is critical for normal GI motility and has been shown to be altered in mouse models of ASD and other neurological disorders. Contactin-associated protein-like 2 (Cntnap2) is an ASD-related synaptic cell-adhesion molecule important for sensory processing. In this study, we examine the role of Cntnap2 in GI motility by characterizing Cntnap2's expression in the ENS and assessing GI function in Cntnap2 mutant mice. We find Cntnap2 expression predominately in enteric sensory neurons. We further assess in-vivo and ex-vivo GI motility in Cntnap2 mutants and show altered transit time and colonic motility patterns. The overall organization of the ENS appears undisturbed. Our results suggest that Cntnap2 plays a role in GI function and may provide a molecular link between ASD and GI dysfunction.
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Affiliation(s)
- Beatriz G. Robinson
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
- Neurosciences IDP Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Beau A. Oster
- Nevada ENDURE Program, University of Nevada, Reno, Reno, NV 89557, USA
| | - Keiramarie Robertson
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
- Neurosciences IDP Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Julia A. Kaltschmidt
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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Gomez-Frittelli J, Hamnett R, Kaltschmidt JA. Comparison of wholemount dissection methods for neuronal subtype marker expression in the mouse myenteric plexus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524014. [PMID: 36711933 PMCID: PMC9882214 DOI: 10.1101/2023.01.17.524014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Background Accurately reporting the identity and representation of enteric nervous system (ENS) neuronal subtypes along the length of the gastrointestinal (GI) tract is critical to advancing our understanding of ENS control of GI tract function. Reports of varying proportions of subtype marker expression have employed different dissection techniques to achieve wholemount muscularis preparations of myenteric plexus. In this study we asked whether differences in GI dissection methods could introduce variability into the quantification of marker expression. Methods We compared three commonly used methods of ENS wholemount dissection: two flat-sheet preparations that differed in the order of microdissection and fixation as well as a rod-mounted peeling technique. We assessed marker expression using immunohistochemistry, genetic reporter lines, confocal microscopy, and automated image analysis. Key Results and Conclusions We found no significant differences between the two flat-sheet preparation methods in the expression of calretinin, neuronal nitric oxide synthase (nNOS), or somatostatin (SST) in ileum myenteric plexus. However, the rod-mounted peeling method resulted in decreased marker labeling for both calretinin and nNOS. This method also resulted in decreased transgenic reporter fluorescent protein (tdTomato) for substance P in ileum and choline acetyltransferase (ChAT) in both ileum and distal colon. These results suggest that labeling among some markers, both native protein and transgenic fluorescent reporters, is decreased by the rod-mounted mechanical method of peeling, demonstrating a critical variability in wholemount muscularis dissection methods.
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Affiliation(s)
- Julieta Gomez-Frittelli
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305 USA
| | - Ryan Hamnett
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305 USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Julia A. Kaltschmidt
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305 USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305 USA
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Hibberd TJ, Yew WP, Dodds KN, Xie Z, Travis L, Brookes SJ, Costa M, Hu H, Spencer NJ. Quantification of CGRP-immunoreactive myenteric neurons in mouse colon. J Comp Neurol 2022; 530:3209-3225. [PMID: 36043843 DOI: 10.1002/cne.25403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 08/08/2022] [Accepted: 08/17/2022] [Indexed: 11/07/2022]
Abstract
Quantitative data of biological systems provide valuable baseline information for understanding pathology, experimental perturbations, and computational modeling. In mouse colon, calcitonin gene-related peptide (CGRP) is expressed by myenteric neurons with multiaxonal (Dogiel type II) morphology, characteristic of intrinsic primary afferent neurons (IPANs). Analogous neurons in other species and gut regions represent 5-35% of myenteric neurons. We aimed to quantify proportions of CGRP-immunopositive (CGRP+) myenteric neurons. Colchicine-treated wholemount preparations of proximal, mid, and distal colon were labeled for HuC/D, CGRP, nitric oxide synthase (NOS), and peripherin (Per). The pan-neuronal markers (Hu+/Per+) co-labeled 94% of neurons. Hu+/Per- neurons comprised ∼6%, but Hu-/Per+ cells were rare. Thus, quantification was based on Hu+ myenteric neurons (8576 total; 1225 ± 239 per animal, n = 7). CGRP+ cell bodies were significantly larger than the average of all Hu+ neurons (329 ± 13 vs. 261 ± 12 μm2 , p < .0001). CGRP+ neurons comprised 19% ± 3% of myenteric neurons without significant regional variation. NOS+ neurons comprised 42% ± 2% of myenteric neurons overall, representing a lower proportion in proximal colon, compared to mid and distal colon (38% ± 2%, 44% ± 2%, and 44% ± 3%, respectively). Peripherin immunolabeling revealed cell body and axonal morphology in some myenteric neurons. Whether all CGRP+ neurons were multiaxonal could not be addressed using peripherin immunolabeling. However, of 118 putatively multiaxonal neurons first identified based on peripherin immunoreactivity, all were CGRP+ (n = 4). In conclusion, CGRP+ myenteric neurons in mouse colon were comprehensively quantified, occurring within a range expected of a putative IPAN marker. All Per+ multiaxonal neurons, characteristic of Dogiel type II/IPAN morphology, were CGRP+.
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Affiliation(s)
- Timothy J Hibberd
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Wai Ping Yew
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Kelsi N Dodds
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Zili Xie
- Department of Anesthesiology, The Center for the Study of Itch & Sensory Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lee Travis
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Simon J Brookes
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Marcello Costa
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
| | - Hongzhen Hu
- Department of Anesthesiology, The Center for the Study of Itch & Sensory Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nick J Spencer
- College of Medicine and Public Health, Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia
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