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Qiu P, Li D, Xiao C, Xu F, Chen X, Chang Y, Liu L, Zhang L, Zhao Q, Chen Y. The Eph/ephrin system symphony of gut inflammation. Pharmacol Res 2023; 197:106976. [PMID: 38032293 DOI: 10.1016/j.phrs.2023.106976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/15/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023]
Abstract
The extent of gut inflammation depends largely on the gut barrier's integrity and enteric neuroimmune interactions. However, the factors and molecular mechanisms that regulate inflammation-related changes in the enteric nervous system (ENS) remain largely unexplored. Eph/ephrin signaling is critical for inflammatory response, neuronal activation, and synaptic plasticity in the brain, but its presence and function in the ENS have been largely unknown to date. This review discusses the critical role of Eph/ephrin in regulating gut homeostasis, inflammation, neuroimmune interactions, and pain pathways. Targeting the Eph/ephrin system offers innovative treatments for gut inflammation disorders, offering hope for enhanced patient prognosis, pain management, and overall quality of life.
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Affiliation(s)
- Peishan Qiu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Daojiang Li
- Department of General Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Cong Xiao
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Fei Xu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Xiaoyu Chen
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Ying Chang
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Lan Liu
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China
| | - Lei Zhang
- Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Qiu Zhao
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China.
| | - Yuhua Chen
- Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan 430071, China; Hubei Clinical Center & Key Lab of Intestinal & Colorectal Diseases, Wuhan 430071, China.
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van Baarle L, Stakenborg M, Matteoli G. Enteric neuro-immune interactions in intestinal health and disease. Semin Immunol 2023; 70:101819. [PMID: 37632991 DOI: 10.1016/j.smim.2023.101819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 07/19/2023] [Accepted: 08/11/2023] [Indexed: 08/28/2023]
Abstract
The enteric nervous system is an autonomous neuronal circuit that regulates many processes far beyond the peristalsis in the gastro-intestinal tract. This circuit, consisting of enteric neurons and enteric glial cells, can engage in many intercellular interactions shaping the homeostatic microenvironment in the gut. Perhaps the most well documented interactions taking place, are the intestinal neuro-immune interactions which are essential for the fine-tuning of oral tolerance. In the context of intestinal disease, compelling evidence demonstrates both protective and detrimental roles for this bidirectional neuro-immune signaling. This review discusses the different immune cell types that are recognized to engage in neuronal crosstalk during intestinal health and disease. Highlighting the molecular pathways involved in the neuro-immune interactions might inspire novel strategies to target intestinal disease.
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Affiliation(s)
- Lies van Baarle
- Department of Chronic Diseases and Metabolism (CHROMETA), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Herestraat 49, O&N1 box 701, 3000 Leuven, Belgium
| | - Michelle Stakenborg
- Department of Chronic Diseases and Metabolism (CHROMETA), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Herestraat 49, O&N1 box 701, 3000 Leuven, Belgium
| | - Gianluca Matteoli
- Department of Chronic Diseases and Metabolism (CHROMETA), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Herestraat 49, O&N1 box 701, 3000 Leuven, Belgium.
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Machado FA, Souza RF, Figliuolo VR, Coutinho-Silva R, Castelucci P. Effects of experimental ulcerative colitis on myenteric neurons in P2X7-knockout mice. Histochem Cell Biol 2023; 160:321-339. [PMID: 37306742 DOI: 10.1007/s00418-023-02208-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2023] [Indexed: 06/13/2023]
Abstract
This study aimed to investigate the distal colon myenteric plexus and enteric glial cells (EGCs) in P2X7 receptor-deficient (P2X7-/-) animals after the induction of experimental ulcerative colitis. 2,4,6-Trinitrobenzene sulfonic acid (TNBS) was injected into the distal colon of C57BL/6 (WT) and P2X7 receptor gene-deficient (P2X7-/-, KO) animals. Distal colon tissues in the WT and KO groups were analyzed 24 h and 4 days after administration. The tissues were analyzed by double immunofluorescence of the P2X7 receptor with neuronal nitric oxide synthase (nNOS)-immunoreactive (ir), choline acetyltransferase (ChAT)-ir, and PGP9.5 (pan neuronal)-ir, and their morphology was assessed by histology. The quantitative analysis revealed 13.9% and 7.1% decreases in the number of P2X7 receptor-immunoreactive (ir) per ganglion in the 24 h-WT/colitis and 4 day-WT/colitis groups, respectively. No reduction in the number of nNOS-ir, choline ChAT-ir, and PGP9.5-ir neurons per ganglion was observed in the 4 day-KO/colitis group. In addition, a reduction of 19.3% in the number of GFAP (glial fibrillary acidic protein)-expressing cells per ganglion was found in the 24 h-WT/colitis group, and a 19% increase in the number of these cells was detected in the 4 day-WT/colitis group. No profile area changes in neurons were observed in the 24 h-WT and 24 h-KO groups. The 4 day-WT/colitis and 4 day-KO/colitis groups showed increases in the profile neuronal areas of nNOS, ChAT, and PGP9.5. The histological analysis showed hyperemia, edema, or cellular infiltration in the 24 h-WT/colitis and 4 day-WT/colitis groups. Edema was observed in the 4 day-KO/colitis group, which showed no histological changes compared with the 24 h-KO/colitis group. We concluded that ulcerative colitis differentially affected the neuronal classes in the WT and KO animals, demonstrating the potential participation and neuroprotective effect of the P2X7 receptor in enteric neurons in inflammatory bowel disease.
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Affiliation(s)
- Felipe Alexandre Machado
- Department of Anatomy, Institute Biomedical and Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil
| | - Roberta Figueiroa Souza
- Department of Anatomy, Institute Biomedical and Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil
| | | | | | - Patricia Castelucci
- Department of Anatomy, Institute Biomedical and Sciences, University of São Paulo, Av. Prof. Dr. Lineu Prestes, 2415, São Paulo, CEP 05508-900, Brazil.
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Caetano MAF, Magalhães HIR, Duarte JRL, Conceição LB, Castelucci P. Butyrate Protects Myenteric Neurons Loss in Mice Following Experimental Ulcerative Colitis. Cells 2023; 12:1672. [PMID: 37443707 PMCID: PMC10340616 DOI: 10.3390/cells12131672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 07/15/2023] Open
Abstract
The enteric nervous system is affected by inflammatory bowel diseases (IBD). Gut microbiota ferments dietary fibers and produces short-chain fatty acids, such as Butyrate, which bind to G protein-coupled receptors, such as GPR41, and contribute to maintaining intestinal health. This work aimed to study the GPR41 in myenteric neurons and analyze the effect of Butyrate in mice submitted to experimental ulcerative colitis. The 2, 4, 6 trinitrobenzene sulfonic acid (TNBS) was injected intrarectally in C57BL/6 mice (Colitis). Sham group received ethanol (vehicle). One group was treated with 100 mg/kg of Sodium Butyrate (Butyrate), and the other groups received saline. Animals were euthanized 7 days after colitis induction. Analyzes demonstrated colocalization of GPR41 with neurons immunoreactive (-ir) to nNOS and ChAT-ir and absence of colocalization of the GPR41 with GFAP-ir glia. Quantitative results demonstrated losses of nNOS-ir, ChAT-ir, and GPR41-ir neurons in the Colitis group and Butyrate treatment attenuated neuronal loss. The number of GFAP-ir glia increased in the Colitis group, whereas Butyrate reduced the number of these cells. In addition, morphological alterations observed in the Colitis group were attenuated in the Butyrate group. The presence of GPR41 in myenteric neurons was identified, and the treatment with Butyrate attenuated the damage caused by experimental ulcerative colitis.
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Affiliation(s)
- Marcos A. F. Caetano
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; (M.A.F.C.); (J.R.L.D.); (L.B.C.)
| | - Henrique I. R. Magalhães
- Department of Surgery, School of Veterinary Medicine and Animal Sciences, University of São Paulo, São Paulo 05508-270, Brazil;
| | - Jheniffer R. L. Duarte
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; (M.A.F.C.); (J.R.L.D.); (L.B.C.)
| | - Laura B. Conceição
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; (M.A.F.C.); (J.R.L.D.); (L.B.C.)
| | - Patricia Castelucci
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil; (M.A.F.C.); (J.R.L.D.); (L.B.C.)
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Magalhães HIR, Machado FA, Souza RF, Caetano MAF, Figliuolo VR, Coutinho-Silva R, Castelucci P. Study of the roles of caspase-3 and nuclear factor kappa B in myenteric neurons in a P2X7 receptor knockout mouse model of ulcerative colitis. World J Gastroenterol 2023; 29:3440-3468. [PMID: 37389242 PMCID: PMC10303518 DOI: 10.3748/wjg.v29.i22.3440] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/25/2023] [Accepted: 05/12/2023] [Indexed: 06/06/2023] Open
Abstract
BACKGROUND The literature indicates that the enteric nervous system is affected in inflammatory bowel diseases (IBDs) and that the P2X7 receptor triggers neuronal death. However, the mechanism by which enteric neurons are lost in IBDs is unknown.
AIM To study the role of the caspase-3 and nuclear factor kappa B (NF-κB) pathways in myenteric neurons in a P2X7 receptor knockout (KO) mouse model of IBDs.
METHODS Forty male wild-type (WT) C57BL/6 and P2X7 receptor KO mice were euthanized 24 h or 4 d after colitis induction by 2,4,6-trinitrobenzene sulfonic acid (colitis group). Mice in the sham groups were injected with vehicle. The mice were divided into eight groups (n = 5): The WT sham 24 h and 4 d groups, the WT colitis 24 h and 4 d groups, the KO sham 24 h and 4 d groups, and the KO colitis 24 h and 4 d groups. The disease activity index (DAI) was analyzed, the distal colon was collected for immunohistochemistry analyses, and immunofluorescence was performed to identify neurons immunoreactive (ir) for calretinin, P2X7 receptor, cleaved caspase-3, total caspase-3, phospho-NF-κB, and total NF-κB. We analyzed the number of calretinin-ir and P2X7 receptor-ir neurons per ganglion, the neuronal profile area (µm²), and corrected total cell fluorescence (CTCF).
RESULTS Cells double labeled for calretinin and P2X7 receptor, cleaved caspase-3, total caspase-3, phospho-NF-κB, or total NF-κB were observed in the WT colitis 24 h and 4 d groups. The number of calretinin-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (2.10 ± 0.13 vs 3.33 ± 0.17, P < 0.001; 2.92 ± 0.12 vs 3.70 ± 0.11, P < 0.05), but was not significantly different between the KO groups. The calretinin-ir neuronal profile area was increased in the WT colitis 24 h group compared to the WT sham 24 h group (312.60 ± 7.85 vs 278.41 ± 6.65, P < 0.05), and the nuclear profile area was decreased in the WT colitis 4 d group compared to the WT sham 4 d group (104.63 ± 2.49 vs 117.41 ± 1.14, P < 0.01). The number of P2X7 receptor-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (19.49 ± 0.35 vs 22.21 ± 0.18, P < 0.001; 20.35 ± 0.14 vs 22.75 ± 0.51, P < 0.001), and no P2X7 receptor-ir neurons were observed in the KO groups. Myenteric neurons showed ultrastructural changes in the WT colitis 24 h and 4 d groups and in the KO colitis 24 h group. The cleaved caspase-3 CTCF was increased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (485949 ± 14140 vs 371371 ± 16426, P < 0.001; 480381 ± 11336 vs 378365 ± 4053, P < 0.001), but was not significantly different between the KO groups. The total caspase-3 CTCF, phospho-NF-κB CTCF, and total NF-κB CTCF were not significantly different among the groups. The DAI was recovered in the KO groups. Furthermore, we demonstrated that the absence of the P2X7 receptor attenuated inflammatory infiltration, tissue damage, collagen deposition, and the decrease in the number of goblet cells in the distal colon.
CONCLUSION Ulcerative colitis affects myenteric neurons in WT mice but has a weaker effect in P2X7 receptor KO mice, and neuronal death may be associated with P2X7 receptor-mediated caspase-3 activation. The P2X7 receptor can be a therapeutic target for IBDs.
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Affiliation(s)
| | | | | | | | - Vanessa Ribeiro Figliuolo
- Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Robson Coutinho-Silva
- Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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Souza RF, Caetano MAF, Magalhães HIR, Castelucci P. Study of tumor necrosis factor receptor in the inflammatory bowel disease. World J Gastroenterol 2023; 29:2733-2746. [PMID: 37274062 PMCID: PMC10237104 DOI: 10.3748/wjg.v29.i18.2733] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/14/2023] [Accepted: 04/04/2023] [Indexed: 05/11/2023] Open
Abstract
Ulcerative colitis (UC) and Crohn’s disease (CD) are part of Inflammatory Bowel Diseases (IBD) and have pathophysiological processes such as bowel necrosis and enteric neurons and enteric glial cells. In addition, the main inflammatory mediator is related to the tumor necrosis factor-alpha (TNF-α). TNF-α is a me-diator of the intestinal inflammatory processes, thus being one of the main cytokines involved in the pathogenesis of IBD, however, its levels, when measured, are present in the serum of patients with IBD. In addition, TNF-α plays an important role in promoting inflammation, such as the production of interleukins (IL), for instance IL-1β and IL-6. There are two receptors for TNF as following: The tumor necrosis factor 1 receptor (TNFR1); and the tumor necrosis factor 2 receptor (TNFR2). They are involved in the pathogenesis of IBD and their receptors have been detected in IBD and their expression is correlated with disease activity. The soluble TNF form binds to the TNFR1 receptor with, and its activation results in a signaling cascade effects such as apoptosis, cell proliferation and cytokine secretion. In contrast, the transmembrane TNF form can bind both to TNFR1 and TNFR2. Recent studies have suggested that TNF-α is one of the main pro-inflammatory cytokines involved in the pathogenesis of IBD, since TNF levels are present in the serum of both patients with UC and CD. Intravenous and subcutaneous biologics targeting TNF-α have revolutionized the treatment of IBD, thus becoming the best available agents to induce and maintain IBD remission. The application of antibodies aimed at neutralizing TNF-α in patients with IBD that induce a satisfactory clinical response in up to 60% of patients, and also induced long-term maintenance of disease remission in most patients. It has been suggested that anti-TNF-α agents inactivate the pro-inflammatory cytokine TNF-α by direct neutralization, i.e., resulting in suppression of inflammation. However, anti-TNF-α antibodies perform more complex functions than a simple blockade.
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Affiliation(s)
- Roberta Figueiroa Souza
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | | | | | - Patricia Castelucci
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
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Structural characterization of peach gum polysaccharide and its effects on the regulation of DSS-induced acute colitis. Int J Biol Macromol 2023; 225:1224-1234. [PMID: 36427612 DOI: 10.1016/j.ijbiomac.2022.11.183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
The structure and the effect of polysaccharide from peach gum (DPG2) on ameliorating DSS-induced acute colitis in mice were investigated in the present study. The results showed that DPG2 was identified as an AG II arabinogalactan with the backbone of β-D-(1 → 6)-galactan, which consisted of mannose, glucuronic acid, galactose, xylose and arabinose with a molar ratio of 4.64:1.02:2.61:39.82:3.89:48.02. Moreover, DPG2 behaved as a flexible chain conformation with a coil-like structure with a molecular weight (Mw) of 5.21 × 105 g/mol. Furthermore, the worm-like chain model parameters for DPG2 were estimated as follows: ML = 379 nm-1, q = 0.74 nm and d = 0.82 nm. The results of the animal assay showed that the intake of DPG2 not only effectively improved the phenotypes of DSS-induced colitis in mice, but also significantly improved the oxidative stress status of mice, such as regulating NO content and T-SOD and MPO levels and repairing oxidative damage to the colonic mucosa. Moreover, DPG2 improved the inflammation of DSS-induced colitis in mice by inhibiting the secretion of the proinflammatory cytokines TNF-α, IFN-γ, IL-1β, IL-6 and IL-17. Therefore, these results suggested that peach gum polysaccharide showed protective effects against colitis, and has great potential for the application of functional components in the food industry.
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Mendes CE, Palombit K, Alves Pereira TT, Riceti Magalhães HI, Ferreira Caetano MA, Castelucci P. Effects of probenecid and brilliant blue G on rat enteric glial cells following intestinal ischemia and reperfusion. Acta Histochem 2023; 125:151985. [PMID: 36495673 DOI: 10.1016/j.acthis.2022.151985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
The P2X7 receptor participates in several intracellular events and acts with the pannexin-1 channel. This study examined the effects of probenecid (PB) and brilliant blue G (BBG), which are antagonists of the pannexin-1 channel and P2X7 receptor, respectively, on rat ileum enteric glial cells after on ischemia and reperfusion. The ileal vessels were occluded for 45 min with nontraumatic vascular tweezers, and reperfusion was performed for periods of 24 h and 14 and 28 days. After ischemia (IR groups), the animals were treated with BBG (BG group) or PB (PB group). The double-labeling results demonstrated the following: the P2X7 receptor was present in enteric glial cells (S100β) and enteric neurons positive for HuC/D; enteric glial cells exhibited different phenotypes; some enteric glial cells were immunoreactive to only S100β or GFAP; and the pannexin-1 channel was present in enteric glial cells (GFAP). Density (in cells/cm2) analyses showed that the IR group exhibited a decrease in the number of cells immunoreactive for the P2X7 receptor, pannexin-1, and HuC/D and that treatment with BBG or PB resulted in the recovery of the numbers of these cells. The number of glial cells (S100β and GFAP) was higher in the IR group, and the treatments decreased the number of these cells to the normal value. However, the PB group did not exhibit recovery of S100β-positive glia. The cell profile area (μm2) of S100β-positive enteric glial cells decreased to the normal value after BBG treatment, whereas no recovery was observed in the PB group. The ileum contractile activity was decreased in the IR group and returned to baseline in the BG and PB groups. BBG and PB can effectively induce the recovery of neurons and glia cells and are thus potential therapeutic agents in the treatment of gastrointestinal tract diseases.
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Affiliation(s)
| | - Kelly Palombit
- Department of Morphology, University Federal of Piaui, Brazil
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Schäfer W, Stähler T, Pinto Espinoza C, Danquah W, Knop JH, Rissiek B, Haag F, Koch-Nolte F. Origin, distribution, and function of three frequent coding polymorphisms in the gene for the human P2X7 ion channel. Front Pharmacol 2022; 13:1033135. [DOI: 10.3389/fphar.2022.1033135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/28/2022] [Indexed: 11/20/2022] Open
Abstract
P2X7, an ion channel gated by extracellular ATP, is widely expressed on the plasma membrane of immune cells and plays important roles in inflammation and apoptosis. Several single nucleotide polymorphisms have been identified in the human P2RX7 gene. In contrast to other members of the P2X family, non-synonymous polymorphisms in P2X7 are common. Three of these occur at overall frequencies of more than 25% and affect residues in the extracellular “head”-domain of P2X7 (155 Y/H), its “lower body” (270 R/H), and its “tail” in the second transmembrane domain (348 T/A). Comparison of the P2X7 orthologues of human and other great apes indicates that the ancestral allele is Y—R—T (at 155–270–348). Interestingly, each single amino acid variant displays lower ATP-sensitivity than the ancestral allele. The originally published reference sequence of human P2X7, often referred to as “wildtype,” differs from the ancestral allele at all three positions, i.e. H—H—A. The 1,000 Genome Project determined the sequences of both alleles of 2,500 human individuals, including roughly 500 persons from each of the five major continental regions. This rich resource shows that the ancestral alleles Y155, R270, and T348 occur in all analyzed human populations, albeit at strikingly different frequencies in various subpopulations (e.g., 25%–59% for Y155, 59%–77% for R270, and 13%–47% for T348). BLAST analyses of ancient human genome sequences uncovered several homozygous carriers of variant P2X7 alleles, possibly reflecting a high degree of inbreeding, e.g., H—R—T for a 50.000 year old Neanderthal, H—R—A for a 24.000 year old Siberian, and Y—R—A for a 7,000 year old mesolithic European. In contrast, most present-day individuals co-express two copies of P2X7 that differ in one or more amino acids at positions 155, 270, and 348. Our results improve the understanding of how P2X7 structure affects its function and suggest the importance of considering P2X7 variants of participants when designing clinical trials targeting P2X7.
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Ballout J, Claßen R, Richter K, Grau V, Diener M. Ionotropic P2X
4
and P2X
7
receptors in the regulation of ion transport across rat colon. Br J Pharmacol 2022; 179:4992-5011. [DOI: 10.1111/bph.15928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/18/2022] [Accepted: 07/09/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
- Jasmin Ballout
- Institute for Veterinary Physiology and Biochemistry Justus Liebig University Giessen Germany
| | - Rebecca Claßen
- Institute for Veterinary Physiology and Biochemistry Justus Liebig University Giessen Germany
| | - Katrin Richter
- Laboratory of Experimental Surgery, Departement of General Surgery, German Centre for Lung Research (DZL) Justus Liebig University Giessen Germany
| | - Veronika Grau
- Laboratory of Experimental Surgery, Departement of General Surgery, German Centre for Lung Research (DZL) Justus Liebig University Giessen Germany
| | - Martin Diener
- Institute for Veterinary Physiology and Biochemistry Justus Liebig University Giessen Germany
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