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Cardona-Mendoza A, Roa Molina NS, Castillo DM, Lafaurie GI, Gualtero Escobar DF. Human Coronary Artery Endothelial Cell Response to Porphyromonas gingivalis W83 in a Collagen Three-Dimensional Culture Model. Microorganisms 2024; 12:248. [PMID: 38399652 PMCID: PMC10892777 DOI: 10.3390/microorganisms12020248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/25/2024] Open
Abstract
P. gingivalis has been reported to be an endothelial cell inflammatory response inducer that can lead to endothelial dysfunction processes related to atherosclerosis; however, these studies have been carried out in vitro in cell culture models on two-dimensional (2D) plastic surfaces that do not simulate the natural environment where pathology develops. This work aimed to evaluate the pro-inflammatory response of human coronary artery endothelial cells (HCAECs) to P. gingivalis in a 3D cell culture model compared with a 2D cell culture. HCAECs were cultured for 7 days on type I collagen matrices in both cultures and were stimulated at an MOI of 1 or 100 with live P. gingivalis W83 for 24 h. The expression of the genes COX-2, eNOS, and vWF and the levels of the pro-inflammatory cytokines thromboxane A2 (TXA-2) and prostaglandin I2 (PGI2) were evaluated. P. gingivalis W83 in the 2D cell culture increased IL-8 levels at MOI 100 and decreased MCP-1 levels at both MOI 100 and MOI 1. In contrast, the 3D cell culture induced an increased gene expression of COX-2 at both MOIs and reduced MCP-1 levels at MOI 100, whereas the gene expression of eNOS, vWF, and IL-8 and the levels of TXA2 and PGI2 showed no significant changes. These data suggest that in the collagen 3D culture model, P. gingivalis W83 induces a weak endothelial inflammatory response.
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Affiliation(s)
- Andrés Cardona-Mendoza
- Grupo de Inmunología Celular y Molecular Universidad El Bosque-INMUBO, Vicerrectoría de Investigaciones, Facultad de Odontología, Universidad El Bosque, Bogota 11001, Colombia;
- Unidad de Investigación Básica Oral-UIBO, Vicerrectoría de Investigaciones, Facultad de Odontología, Universidad El Bosque, Bogota 11001, Colombia; (D.M.C.); (G.I.L.)
| | - Nelly Stella Roa Molina
- Centro de Investigaciones Odontológicas (CIO), Facultad de Odontología, Pontificia Universidad Javeriana, Bogota 110231, Colombia;
| | - Diana Marcela Castillo
- Unidad de Investigación Básica Oral-UIBO, Vicerrectoría de Investigaciones, Facultad de Odontología, Universidad El Bosque, Bogota 11001, Colombia; (D.M.C.); (G.I.L.)
| | - Gloria Inés Lafaurie
- Unidad de Investigación Básica Oral-UIBO, Vicerrectoría de Investigaciones, Facultad de Odontología, Universidad El Bosque, Bogota 11001, Colombia; (D.M.C.); (G.I.L.)
| | - Diego Fernando Gualtero Escobar
- Unidad de Investigación Básica Oral-UIBO, Vicerrectoría de Investigaciones, Facultad de Odontología, Universidad El Bosque, Bogota 11001, Colombia; (D.M.C.); (G.I.L.)
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Chen K, You J, Yang S, Meng X, Chen X, Wu L, Yu X, Xiao J, Feng J. Abnormally elevated expression of ACTA2 of circular smooth muscle leads to hyperactive contraction in aganglionic segments of HSCR. Pediatr Surg Int 2023; 39:214. [PMID: 37278766 PMCID: PMC10244273 DOI: 10.1007/s00383-023-05479-x] [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] [Accepted: 05/02/2023] [Indexed: 06/07/2023]
Abstract
BACKGROUND Actin Alpha 2 (ACTA2) is expressed in intestinal smooth muscle cells (iSMCs) and is associated with contractility. Hirschsprung disease (HSCR), one of the most common digested tract malformations, shows peristaltic dysfunction and spasm smooth muscles. The arrangement of the circular and longitudinal smooth muscle (SM) of the aganglionic segments is disorganized. Does ACTA2, as a marker of iSMCs, exhibit abnormal expression in aganglionic segments? Does the ACTA2 expression level affect the contraction function of iSMCs? What are the spatiotemporal expression trends of ACTA2 during different developmental stages of the colon? METHODS Immunohistochemical staining was used to detect the expression of ACTA2 in iSMCs of children with HSCR and Ednrb-/- mice, and the small interfering RNAs (siRNAs) knockdown technique was employed to investigate how Acta2 affected the systolic function of iSMCs. Additionally, Ednrb-/- mice were used to explore the changes in the expression level of iSMCs ACTA2 at different developmental stages. RESULTS The expression of ACTA2 is higher in circular SM in the aganglionic segments of HSCR patients and Ednrb-/- mice than in normal control children and mice. Down regulation of Acta2 weakens the contraction ability of intestinal smooth muscle cells. Abnormally elevated expression of ACTA2 of circular smooth muscle occurs since embryonic day 15.5 (E15.5d) in aganglionic segments of Ednrb-/- mice. CONCLUSIONS Abnormally elevated expression of ACTA2 in the circular SM leads to hyperactive contraction, which may cause the spasm of aganglionic segments in HSCR.
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Affiliation(s)
- Ke Chen
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Jingyi You
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Shimin Yang
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Xinyao Meng
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Xuyong Chen
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Luyao Wu
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Xiaosi Yu
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China
| | - Jun Xiao
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China.
| | - Jiexiong Feng
- Department of Pediatric Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, 430043, China.
- Hubei Clinical Center of Hirschsprung Disease and Allied Disorders, Wuhan, China.
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Shikaya Y, Inaba M, Tadokoro R, Utsunomiya S, Takahashi Y. Optogenetic control of gut movements reveals peristaltic wave-mediated induction of cloacal contractions and reactivation of impaired gut motility. Front Physiol 2023; 14:1175951. [PMID: 37293264 PMCID: PMC10245550 DOI: 10.3389/fphys.2023.1175951] [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: 02/28/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023] Open
Abstract
Gut peristalsis, recognized as a wave-like progression along the anterior-posterior gut axis, plays a pivotal role in the transportation, digestion, and absorption of ingested materials. The embryonic gut, which has not experienced ingested materials, undergoes peristalsis offering a powerful model for studying the intrinsic mechanisms underlying the gut motility. It has previously been shown in chicken embryos that acute contractions of the cloaca (an anus-like structure) located at the posterior end of the hindgut are tightly coupled with the arrival of hindgut-derived waves. To further scrutinize the interactions between hindgut and cloaca, we here developed an optogenetic method that produced artificial waves in the hindgut. A variant form of channelrhodopsin-2 (ChR2(D156C)), permitting extremely large photocurrents, was expressed in the muscle component of the hindgut of chicken embryos using Tol2-mediated gene transfer and in ovo electroporation techniques. The D156C-expressing hindgut responded efficiently to local pulses of blue light: local contractions emerge at an ectopic site in the hindgut, which were followed by peristaltic waves that reached to the endpoint of the hindgut. Markedly, the arrival of the optogenetically induced waves caused concomitant contractions of the cloaca, revealing that the hindgut-cloaca coordination is mediated by signals triggered by peristaltic waves. Moreover, a cloaca undergoing pharmacologically provoked aberrant contractions could respond to pulsed blue light irradiation. Together, the optogenetic technology developed in this study for inducing gut peristalsis paves the way to study the gut movement and also to explore therapeutic methodology for peristaltic disorders.
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Endothelial regulation of calmodulin expression and eNOS-calmodulin interaction in vascular smooth muscle. Mol Cell Biochem 2022; 477:1489-1498. [PMID: 35171400 DOI: 10.1007/s11010-022-04391-7] [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: 06/30/2021] [Accepted: 02/10/2022] [Indexed: 10/19/2022]
Abstract
Calmodulin (CaM) is a Ca2+ sensor protein that is required for numerous vascular smooth muscle cell (VSMC) functions. Since CaM is not expressed enough for its many target proteins, factors that modulate its expression and interactions with targets in VSMCs can have extensive effects on vascular functions. VSMCs receive many regulatory inputs from endothelial cells (ECs). However, it is unknown if ECs regulate vascular functions via controlling expression of CaM and its interactions in VSMCs. In this work, we tested the hypothesis that ECs also affect VSMC signaling via regulation of CaM expression and interactions with its target proteins in VSMCs. Using ECs and VSMCs isolated from the same vessels and grown in a co-culture system, we observed that the presence of proliferating ECs significantly upregulates total CaM expression in VSMCs. An imaging module was devised to concurrently measure free Ca2+ and CaM levels in VSMCs in co-culture with ECs. Using indo-1/AM and a CaM biosensor built from a modified CaM-binding sequence of endothelial nitric oxide synthase (eNOS), this system revealed that in response to a generic Ca2+ signal, free Ca2+-bound CaM level is enhanced ~ threefold in VSMCs in co-culture with proliferating ECs. Interestingly, VSMCs express eNOS and eNOS-CaM association in response to the same Ca2+ stimulus is also enhanced ~ threefold in VSMCs co-cultured with ECs. Mechanistically, the endothelium-dependent upregulation of CaM in VSMCs is not affected by inhibition of NO production or endothelin receptors but is prevented by inhibition of vascular endothelial growth factor receptors. Consistently, VEGF-A level is upregulated in VSMCs co-cultured with proliferating ECs. These data indicate a new role of the endothelium in regulating vascular functions via upregulating CaM and its interactions in VSMCs.
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Martire D, Garnier S, Sagnol S, Bourret A, Marchal S, Chauvet N, Guérin A, Forgues D, Berrebi D, Chardot C, Bellaiche M, Rendu J, Kalfa N, Faure S, de Santa Barbara P. Phenotypic switch of smooth muscle cells in paediatric chronic intestinal pseudo-obstruction syndrome. J Cell Mol Med 2021; 25:4028-4039. [PMID: 33656779 PMCID: PMC8051695 DOI: 10.1111/jcmm.16367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 12/31/2020] [Accepted: 01/12/2021] [Indexed: 12/11/2022] Open
Abstract
Smooth Muscle Cells (SMC) are unique amongst all muscle cells in their capacity to modulate their phenotype. Indeed, SMCs do not terminally differentiate but instead harbour a remarkable capacity to dedifferentiate, switching between a quiescent contractile state and a highly proliferative and migratory phenotype, a quality often associated to SMC dysfunction. However, phenotypic plasticity remains poorly examined in the field of gastroenterology in particular in pathologies in which gut motor activity is impaired. Here, we assessed SMC status in biopsies of infants with chronic intestinal pseudo-obstruction (CIPO) syndrome, a life-threatening intestinal motility disorder. We showed that CIPO-SMCs harbour a decreased level of contractile markers. This phenotype is accompanied by an increase in Platelet-Derived Growth Factor Receptor-alpha (PDGFRA) expression. We showed that this modulation occurs without origin-related differences in CIPO circular and longitudinal-derived SMCs. As we characterized PDGFRA as a marker of digestive mesenchymal progenitors during embryogenesis, our results suggest a phenotypic switch of the CIPO-SMC towards an undifferentiated stage. The development of CIPO-SMC culture and the characterization of SMC phenotypic switch should enable us to design therapeutic approaches to promote SMC differentiation in CIPO.
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Affiliation(s)
- Delphine Martire
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Sarah Garnier
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France.,Visceral Paediatric Surgery Unit, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Sébastien Sagnol
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Annick Bourret
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Stéphane Marchal
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Norbert Chauvet
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Amandine Guérin
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Dominique Forgues
- Visceral Paediatric Surgery Unit, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Dominique Berrebi
- Department of Paediatric Gastroenterology, Assistance Publique Hôpitaux (APHP) Hospital Robert Debré, Paris, France
| | | | - Marc Bellaiche
- Department of Paediatric Gastroenterology, Assistance Publique Hôpitaux (APHP) Hospital Robert Debré, Paris, France
| | - John Rendu
- Centre Hospitalier Universitaire de Grenoble Alpes, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Nicolas Kalfa
- Visceral Paediatric Surgery Unit, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Sandrine Faure
- PhyMedExp, Université de Montpellier, CNRS, INSERM, Montpellier, France
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6
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Changes in Gastric Smooth Muscle Cell Contraction during Pregnancy: Effect of Estrogen. J Pregnancy 2019; 2019:4302309. [PMID: 31080672 PMCID: PMC6475543 DOI: 10.1155/2019/4302309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/14/2019] [Indexed: 12/19/2022] Open
Abstract
It is well known that pregnancy is associated with frequent gastrointestinal (GI) disorders and symptoms. Moreover, previous reports have shown that estrogen, which changes in levels during pregnancy, participates in the regulation of GI motility and is involved in the pathogenesis of various functional disorders in the stomach. The aim of the current study was to explore the changes in the expression of estrogen receptors (ERs) and examine the effect of estrogen on nitric oxide- (NO-) cyclic guanosine monophosphate (cGMP) pathway and thus relaxation in gastric smooth muscle cells (GSMC) during pregnancy. Single GSMC from early-pregnant and late-pregnant Sprague-Dawley rats were used. Protein and mRNA expression levels of ERs were measured via specifically designed enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), respectively. NO and cGMP levels were measured via specifically designed ELISA kits. Effect of estrogen on acetylcholine- (ACh-) induced contraction of single GSMC was measured via scanning micrometry in the presence or absence of the NO synthase inhibitor, N-nitro-L-arginine (L-NNA), or guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ). Estrogen increased both NO and cGMP levels and their levels were greater in early compared to late pregnancy. Expression of ERs was greater in early compared to late pregnancy. ACh induced greater contraction of GSMC in late pregnancy compared to early pregnancy. Estrogen inhibited ACh-induced contraction in both periods of pregnancy. Importantly, pretreatment of GSMC with either L-NNA or ODQ abolished estrogen inhibitory action on muscle contraction. In conclusion, GSMC contractile behavior undergoes drastic changes in response to estrogen during pregnancy and this might explain some of the pregnancy-associated gastric disorders.
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May AT, Crowe MS, Blakeney BA, Mahavadi S, Wang H, Grider JR, Murthy KS. Identification of expression and function of the glucagon-like peptide-1 receptor in colonic smooth muscle. Peptides 2019; 112:48-55. [PMID: 30508636 PMCID: PMC6342651 DOI: 10.1016/j.peptides.2018.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/07/2018] [Accepted: 11/26/2018] [Indexed: 01/01/2023]
Abstract
The insulinotropic effects of the incretin hormone, glucagon-like peptide-1 (GLP-1) are mediated via GLP-1 receptors (GLP-1R) present on pancreatic β cells. GLP-1 causes a decrease in the motility of stomach and intestine which involves both central and peripheral nervous systems. The expression and function of GLP-1R in gastrointestinal smooth muscle, however, are not clear. Muscle strips and isolated muscle cells were prepared from mouse colon and the effect of GLP-1(7-36) amide on acetylcholine (ACh)-induced contraction was measured. Muscle cells in culture were used to identify the expression of GLP-1R and the signaling pathways activated by GLP-1(7-36) amide. GLP-1R was expressed in the mucosal and non-mucosal tissue preparations derived from colon, and in smooth muscle cell cultures devoid of other cells such as enteric neurons. In colonic muscle strips, the addition of GLP-1(7-36) amide caused dose-dependent inhibition of acetylcholine-induced contractions. The effect of GLP-1(7-36) amide was partly inhibited by the neuronal blocker tetrodotoxin and nitric oxide (NO) synthase inhibitor l-NNA suggesting both NO-dependent neural and NO-independent direct effects on smooth muscle. In isolated colonic smooth muscle cells, GLP-1(7-36) amide caused an increase in Gαs activity, cAMP levels, and PKA activity, and inhibited ACh-induced contraction. The effect of GLP-1(7-36) amide on Gαs activity and cAMP levels was blocked by NF449, an inhibitor of Gαs, and the effect of GLP-1(7-36) amide on contraction was blocked by NF449 and myristoylated PKI, an inhibitor of PKA. We conclude that colonic smooth muscle cells express GLP-1R, and GLP-1(7-36) amide inhibits acetylcholine-induced contraction via GLP-1R coupled to the Gαs/cAMP/PKA pathway.
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Affiliation(s)
- Alexander T May
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - Molly S Crowe
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - Bryan A Blakeney
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - Sunila Mahavadi
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - Hongxia Wang
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - John R Grider
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States
| | - Karnam S Murthy
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Box 980551, Richmond, VA, 23298, United States.
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8
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Sanders KM, Ward SM. Nitric oxide and its role as a non-adrenergic, non-cholinergic inhibitory neurotransmitter in the gastrointestinal tract. Br J Pharmacol 2019; 176:212-227. [PMID: 30063800 PMCID: PMC6295421 DOI: 10.1111/bph.14459] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/06/2018] [Accepted: 07/12/2018] [Indexed: 12/19/2022] Open
Abstract
NO is a neurotransmitter released from enteric inhibitory neurons and responsible for modulating gastrointestinal (GI) motor behaviour. Enteric neurons express nNOS (NOS1) that associates with membranes of nerve varicosities. NO released from neurons binds to soluble guanylate cyclase in post-junctional cells to generate cGMP. cGMP-dependent protein kinase type 1 (PKG1) is a major mediator but perhaps not the only pathway involved in cGMP-mediated effects in GI muscles based on gene deletion studies. NOS1+ neurons form close contacts with smooth muscle cells (SMCs), interstitial cells of Cajal (ICC) and PDGFRα+ cells, and these cells are electrically coupled (SIP syncytium). Cell-specific gene deletion studies have shown that nitrergic responses are due to mechanisms in SMCs and ICC. Controversy exists about the ion channels and other post-junctional mechanisms that mediate nitrergic responses in GI muscles. Reduced nNOS expression in enteric inhibitory motor neurons and/or reduced connectivity between nNOS+ neurons and the SIP syncytium appear to be responsible for motor defects that develop in diabetes. An overproduction of NO in some inflammatory conditions also impairs normal GI motor activity. This review summarizes recent findings regarding the role of NO as an enteric inhibitory neurotransmitter. LINKED ARTICLES: This article is part of a themed section on Nitric Oxide 20 Years from the 1998 Nobel Prize. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.2/issuetoc.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno, School of MedicineRenoNVUSA
| | - Sean M Ward
- Department of Physiology and Cell BiologyUniversity of Nevada, Reno, School of MedicineRenoNVUSA
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Al-Shboul OA, Nazzal MS, Mustafa AG, Al-Dwairi AN, Alqudah MA, Abu Omar A, Alfaqih MA, Alsalem MI. Estrogen relaxes gastric muscle cells via a nitric oxide- and cyclic guanosine monophosphate-dependent mechanism: A sex-associated differential effect. Exp Ther Med 2018; 16:1685-1692. [PMID: 30186388 PMCID: PMC6122185 DOI: 10.3892/etm.2018.6406] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/01/2018] [Indexed: 12/22/2022] Open
Abstract
Various gastrointestinal (GI) disorders have a higher prevalence in women than in men. In addition, estrogen has been demonstrated to have an inhibitory effect on the contractility of GI smooth muscle. Although increased plasma estrogen levels have been implicated in GI disorders, the role of gastric estrogen receptor (ER) in these sex-specific differences remains to be fully elucidated. The present study was designed to investigate the sex-associated differences in the expression of the two ER isoforms, ERα and ERβ, and the effect of estrogen on gastric muscle contraction via the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. Experiments were performed on single gastric smooth muscle cells (GSMCs) isolated from male and female Sprague Dawley rats. The effect of acetylcholine (ACh), a muscarinic agonist, on the contraction of GSMCs was measured via scanning micrometry in the presence or absence of 1 µM 17β-estradiol (E2), an agonist to the majority of ERs, 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT), an ERα agonist, or diarylpropionitrile (DPN), an ERβ agonist. The protein expression levels of ER subtypes in GSMCs were measured using a specifically designed ELISA. GSMCs from female rats had a higher expression of ERα and ERβ protein compared with GSMCs from males. ACh induced less contraction in female that in male GSMCs. Pre-treatment of GSMCs with E2 reduced the contraction of GSMCs from both sexes, but to a greater extent in those from females. PPT and DPN inhibited ACh-induced contraction in GSMCs from females. Furthermore, E2 increased NO and cGMP levels in GSMCs from males and females; however, higher levels were measured in females. Of note, pre-incubation of female GSMCs with Nω-nitro-L-arginine, a NO synthase inhibitor, or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a guanylyl cyclase inhibitor, reduced the inhibitory effect of estrogen on GSMC contraction. In conclusion, estrogen relaxes GSMCs via an NO/cGMP-dependent mechanism, and the reduced contraction in GSMCs from females by estrogen may be associated with the sex-associated increased expression of ERα and ERβ, and greater production of NO and cGMP, compared with that in GSMCs from males.
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Affiliation(s)
- Othman A Al-Shboul
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mona S Nazzal
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Ayman G Mustafa
- Department of Anatomy, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Ahmed N Al-Dwairi
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mohammad A Alqudah
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Amal Abu Omar
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mahmoud A Alfaqih
- Department of Physiology and Biochemistry, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Mohammad I Alsalem
- Department of Anatomy and Histology, Faculty of Medicine, Jordan University, Amman 11942, Jordan
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10
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Nalli AD, Wang H, Bhattacharya S, Blakeney BA, Murthy KS. Inhibition of RhoA/Rho kinase pathway and smooth muscle contraction by hydrogen sulfide. Pharmacol Res Perspect 2018; 5. [PMID: 28971603 PMCID: PMC5625153 DOI: 10.1002/prp2.343] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 12/22/2022] Open
Abstract
Hydrogen sulfide (H2 S) plays an important role in smooth muscle relaxation. Here, we investigated the expression of enzymes in H2 S synthesis and the mechanism regulating colonic smooth muscle function by H2 S. Expression of cystathionine-γ-lyase (CSE), but not cystathionine-β-synthase (CBS), was identified in the colonic smooth muscle of rabbit, mouse, and human. Carbachol (CCh)-induced contraction in rabbit muscle strips and isolated muscle cells was inhibited by l-cysteine (substrate of CSE) and NaHS (an exogenous H2 S donor) in a concentration-dependent fashion. H2 S induced S-sulfhydration of RhoA that was associated with inhibition of RhoA activity. CCh-induced Rho kinase activity also was inhibited by l-cysteine and NaHS in a concentration-dependent fashion. Inhibition of CCh-induced contraction by l-cysteine was blocked by the CSE inhibitor, dl-propargylglycine (DL-PPG) in dispersed muscle cells. Inhibition of CCh-induced Rho kinase activity by l-cysteine was blocked by CSE siRNA in cultured cells and DL-PPG in dispersed muscle cells. Stimulation of Rho kinase activity and muscle contraction in response to CCh was also inhibited by l-cysteine or NaHS in colonic muscle cells from mouse and human. Collectively, our studies identified the expression of CSE in colonic smooth muscle and determined that sulfhydration of RhoA by H2 S leads to inhibition of RhoA and Rho kinase activities and muscle contraction. The mechanism identified may provide novel therapeutic approaches to mitigate gastrointestinal motility disorders.
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Affiliation(s)
- Ancy D Nalli
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Hongxia Wang
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Sayak Bhattacharya
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Bryan A Blakeney
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Karnam S Murthy
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
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11
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Kaymaz Y, Oduor CI, Yu H, Otieno JA, Ong'echa JM, Moormann AM, Bailey JA. Comprehensive Transcriptome and Mutational Profiling of Endemic Burkitt Lymphoma Reveals EBV Type-Specific Differences. Mol Cancer Res 2018; 15:563-576. [PMID: 28465297 PMCID: PMC5471630 DOI: 10.1158/1541-7786.mcr-16-0305] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 12/17/2022]
Abstract
Endemic Burkitt lymphoma (eBL) is the most common pediatric cancer in malaria-endemic equatorial Africa and nearly always contains Epstein-Barr virus (EBV), unlike sporadic Burkitt lymphoma (sBL) that occurs with a lower incidence in developed countries. Given these differences and the variable clinical presentation and outcomes, we sought to further understand pathogenesis by investigating transcriptomes using RNA sequencing (RNAseq) from multiple primary eBL tumors compared with sBL tumors. Within eBL tumors, minimal expression differences were found based on: anatomical presentation site, in-hospital survival rates, and EBV genome type, suggesting that eBL tumors are homogeneous without marked subtypes. The outstanding difference detected using surrogate variable analysis was the significantly decreased expression of key genes in the immunoproteasome complex (PSMB9/β1i, PSMB10/β2i, PSMB8/β5i, and PSME2/PA28β) in eBL tumors carrying type 2 EBV compared with type 1 EBV. Second, in comparison with previously published pediatric sBL specimens, the majority of the expression and pathway differences was related to the PTEN/PI3K/mTOR signaling pathway and was correlated most strongly with EBV status rather than geographic designation. Third, common mutations were observed significantly less frequently in eBL tumors harboring EBV type 1, with mutation frequencies similar between tumors with EBV type 2 and without EBV. In addition to the previously reported genes, a set of new genes mutated in BL, including TFAP4, MSH6, PRRC2C, BCL7A, FOXO1, PLCG2, PRKDC, RAD50, and RPRD2, were identified. Overall, these data establish that EBV, particularly EBV type 1, supports BL oncogenesis, alleviating the need for certain driver mutations in the human genome. IMPLICATIONS Genomic and mutational analyses of Burkitt lymphoma tumors identify key differences based on viral content and clinical outcomes suggesting new avenues for the development of prognostic molecular biomarkers and therapeutic interventions.
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Affiliation(s)
- Yasin Kaymaz
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Cliff I Oduor
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Hongbo Yu
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Juliana A Otieno
- Jaramogi Oginga Odinga Teaching and Referral Hospital, Ministry of Health, Kisumu, Kenya
| | | | - Ann M Moormann
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts.
- Division of Transfusion Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
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12
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Meng XM, Huang X, Lu HL, Zhang CM, Kim YC, Chen J, Xu WX. H 2 S-induced gastric fundus smooth muscle tension potentiation is mediated by the phosphoinositide 3-kinase/Akt/endothelial nitric oxide synthase pathway. Exp Physiol 2017; 102:779-790. [PMID: 28383821 DOI: 10.1113/ep086288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/03/2017] [Indexed: 01/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? The present study investigated the relationship between H2 S and NO in regulation of gastric fundus tension. What is the main finding and its importance? Endogenous or exogenous H2 S and NO have opposite effects on fundus tension, and H2 S-induced gastric fundus tension enhancements are mediated by inhibition of NO generation through the phosphoinositide 3-kinase/Akt pathway. These results are very important in exploring the mechanism of physiological accommodation and accommodation disorder. Hydrogen sulphide (H2 S) is considered a new gasotransmitter, along with NO and CO. It was recently confirmed that H2 S and NO play important roles in the regulation of gastrointestinal smooth muscle tension. The present study was designed to elucidate the interactions between H2 S and NO with respect to the regulation of gastric fundus smooth muscle tension using Western blotting, physiological and electrochemical techniques. Real-time H2 S and NO generation was detected in gastric smooth muscle tissue. NaHS, an H2 S donor, enhanced fundus smooth muscle tension, whereas SNP, an NO donor, decreased fundus smooth muscle tension in a dose-dependent manner. NaHS-induced increases in fundus smooth muscle tension were suppressed by l-NAME, an NO synthase inhibitor. Aminooxyacetic acid (AOAA), a cystathionine β-synthase inhibitor, exerted inhibitory effects on fundus smooth muscle tension; these effects were also suppressed by l-NAME. Real-time NO generation was significantly potentiated by AOAA. Endothelial nitric oxide synthase (eNOS) phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473 were significantly inhibited by NaHS. LY294002, a phosphoinositide 3-kinase inhibitor, blocked these NaHS-mediated effects. However, eNOS phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473 were significantly potentiated by AOAA. Cystathionine β-synthase siRNA interference significantly increased eNOS phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473. Cystathionine β-synthase siRNA interference also increased total eNOS protein expression levels but did not significantly change total Akt kinase protein expression levels. These results suggest that H2 S-induced enhancement of gastric fundus tension is mediated by inhibition of NO generation through the phosphoinositide 3-kinase/Akt pathway.
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Affiliation(s)
- Xiang-Min Meng
- Department of Physiology, College of Basic Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China
| | - Xu Huang
- Department of Physiology, College of Basic Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China
| | - Hong-Li Lu
- Department of Physiology, College of Basic Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China
| | - Chun-Mei Zhang
- Department of Physiology, College of Basic Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China
| | - Young-Chul Kim
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, Chungbuk 361-763, Republic of Korea
| | - Jie Chen
- Department of Pediatric Surgery, Xin Hua Hospital, Affiliated to Shanghai JiaoTong University School of Medicine, 1665 Kong Jiang Road, 200092, Shanghai, China
| | - Wen-Xie Xu
- Department of Physiology, College of Basic Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China
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13
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Tsai CC, Lee MC, Tey SL, Liu CW, Huang SC. Mechanism of resveratrol-induced relaxation in the human gallbladder. Altern Ther Health Med 2017; 17:254. [PMID: 28482835 PMCID: PMC5422932 DOI: 10.1186/s12906-017-1752-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 04/23/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND Resveratrol is a polyphenolic compound extracted from plants and is also a constituent of red wine. Resveratrol produces relaxation of vascular smooth muscle and may prevent cardiovascular diseases. Although resveratrol has been reported to cause relaxation of the guinea pig gallbladder, limited data are available about the effect of resveratrol on the gallbladder smooth muscle in humans. The purpose of this study was to investigate the relaxation effects of resveratrol in human gallbladder muscle strips. METHODS We studied the relaxant effects of resveratrol in human gallbladder. In addition, we also investigated mechanism of resveratrol-induced relaxation in human gallbladder by tetraethylammonium (a non-selective potassium channels blocker), iberiotoxin (an inhibitor of large conductance calcium-activated potassium channel), glibenclamide (an ATP-sensitive potassium channel blocker), charybdotoxin (an inhibitor of large conductance calcium-activated potassium channels and slowly inactivating voltage-gated potassium channels), apamine (a selective inhibitor of the small conductance calcium-activated potassium channel), KT 5720 (a cAMP-dependent protein kinase A inhibitor), KT 5823 (a cGMP-dependent protein kinase G inhibitor), NG-Nitro-L-arginine (a competitive inhibitor of nitric oxide synthase), tetrodotoxin (a selective neuronal Na+ channel blocker), and ω-conotoxin GVIA (a selective neuronal Ca2+ channel blocker). RESULTS The present study showed that resveratrol has relaxant effects in human gallbladder muscle strips. In addition, we found that resveratrol-induced relaxation in human gallbladder is associated with nitric oxide, ATP-sensitive potassium channel, and large conductance calcium-activated potassium channel pathways. CONCLUSIONS This study provides the first evidence concerning the relaxant effects of resveratrol in human gallbladder muscle strips. Furthermore, these results demonstrate that resveratrol is a potential new drug or health supplement in the treatment of biliary colic.
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14
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Li C, Vu K, Hazelgrove K, Kuemmerle JF. Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy. Am J Physiol Gastrointest Liver Physiol 2015; 309:G888-99. [PMID: 26428636 PMCID: PMC4669353 DOI: 10.1152/ajpgi.00414.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 09/27/2015] [Indexed: 01/31/2023]
Abstract
The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation.
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Affiliation(s)
- Chao Li
- 1Department of Medicine, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia; and
| | - Kent Vu
- 1Department of Medicine, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia; and
| | - Krystina Hazelgrove
- 1Department of Medicine, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia; and
| | - John F. Kuemmerle
- 1Department of Medicine, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia; and ,2Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
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15
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Li C, Iness A, Yoon J, Grider JR, Murthy KS, Kellum JM, Kuemmerle JF. Noncanonical STAT3 activation regulates excess TGF-β1 and collagen I expression in muscle of stricturing Crohn's disease. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:3422-31. [PMID: 25740948 PMCID: PMC4369432 DOI: 10.4049/jimmunol.1401779] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased TGF-β1 and TGF-β1-dependent Collagen I production in intestinal mesenchymal cells result in fibrosis in patients with Montreal B2 fibrostenotic Crohn's disease. Numerous cytokines, including IL-6, are produced by activated mesenchymal cells themselves and activate STAT3. The aim of the current study was to determine the mechanisms by which STAT-3 activation might result in intestinal fibrosis. Cytokine levels were measured by ELISA. STAT3 and suppressor of cytokine signaling 3 protein levels were measured by immunoblot, STAT3-TGFB1 DNA-binding activity by chromatin immunoprecipitation, and TGFB1 transcriptional activity by luciferase reporter assay. TGF-β1 (TGFB1), Collagen1α1, and connective tissue growth factor (CTGF) gene expression was measured by quantitative RT-PCR. The role of STAT3 activation was determined using STAT3 inhibitor, Stattic, and by transfection of STAT3 mutants. Autocrine production of cytokines was increased in muscle cells of B2 phenotype patients from strictures and normal intestine in the same patient and compared with other Crohn's phenotypes, ulcerative colitis, and non-Crohn's patients. A unique pattern of STAT3 phosphorylation emerged: high STAT3(S727) and low STAT3(Y705) in strictures and the opposite in unaffected intestine. TGFB1 transcriptional activity was regulated by phospho-STAT3(S727) and was decreased by Stattic or dominant-negative STAT3(S727A). TGF-β1, COL1A1, and CTGF expression was inhibited by Stattic or dominant-negative STAT3(S727A). Treatment of normal muscle cells with IL-6 or expression of constitutively active STAT3(S727E) phenocopied muscle cells from strictured intestine. Neutralization of autocrine IL-6 reversed STAT3 phosphorylation and normalized expression of TGF-β1 in strictured intestinal muscle. The ability of Stattic to improve development of fibrosis was confirmed in mice with 2,4,6-trinitrobenzenesulfonic acid-induced colitis. We observed a unique phospho-STAT3(S727) response in patients with Montreal B2 Crohn's disease, particularly in response to IL-6 leading to increased TGF-β1, collagen, and CTGF production in ileal strictures.
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Affiliation(s)
- Chao Li
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298
| | - Audra Iness
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298
| | - Jennifer Yoon
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298
| | - John R Grider
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; VCU Program in Enteric Neuromuscular Sciences, Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; and
| | - Karnam S Murthy
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; VCU Program in Enteric Neuromuscular Sciences, Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; and
| | - John M Kellum
- Department of Surgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298
| | - John F Kuemmerle
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; VCU Program in Enteric Neuromuscular Sciences, Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298; and
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16
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Traini C, Faussone-Pellegrini MS, Evangelista S, Mazzaferro K, Cipriani G, Santicioli P, Vannucchi MG. Inner and outer portions of colonic circular muscle: ultrastructural and immunohistochemical changes in rat chronically treated with otilonium bromide. PLoS One 2014; 9:e103237. [PMID: 25122192 PMCID: PMC4133200 DOI: 10.1371/journal.pone.0103237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 06/30/2014] [Indexed: 12/31/2022] Open
Abstract
Rat colonic circular muscle, main target of otilonium bromide (OB) spasmolytic activity, is subdivided in an inner and outer portion. Since the inner one is particularly rich in organelles involved in calcium availability (caveolae, smooth endoplasmic reticulum, mitochondria), the expression of specific markers (Caveolin-1, eNOS, calreticulin, calsequestrin) in comparison with the outer portion was investigated. The possible changes of these organelles and related markers, and of muscarinic receptors (Mr2) were then studied after OB chronic exposition. Rats were treated with 2-20 mg/kg/OB for 10 or 30 days. Proximal colon was processed by electron microscopy, immunohistochemistry, and western blot. In colon strips the stimulated contractility response to muscarinic agonist was investigated. The inner portion showed a higher expression of Caveolin-1 and Mr2, but not of eNOS, calreticulin and calsequestrin, compared to the outer portion. Chronic OB treatment caused similar ultrastructural and immunohistochemical changes in both portions. Organelles and some related markers were increased at 10 days; Mr2 expression and muscle contractility induced by methacholine was increased at 30 days. The present findings: 1) provide new information on the immunohistochemical properties of the inner portion of the circular layer that are in favour of a role it might play in colonic motility distinct from that of the outer portion; 2) demonstrate that chronically administered OB interferes with cell structures and molecules responsible for calcium handling and storage, and modifies cholinergic transmission. In conclusion, chronic OB administration in the colonic circular muscle layer directly interacts with the organelles and molecules calcium-related and with the Mr2.
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Affiliation(s)
- Chiara Traini
- Dept of Experimental and Clinical Medicine, Histology and Embryology Research Unit, Florence, Italy
| | | | | | - Katia Mazzaferro
- Dept of Experimental and Clinical Medicine, Histology and Embryology Research Unit, Florence, Italy
| | - Gianluca Cipriani
- Enteric Neuroscience Program, Division of Gastroenterology, Dept of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America
| | - Paolo Santicioli
- Dept of Experimental and Clinical Medicine, Histology and Embryology Research Unit, Florence, Italy
| | - Maria Giuliana Vannucchi
- Dept of Experimental and Clinical Medicine, Histology and Embryology Research Unit, Florence, Italy
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17
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Huang J, Nalli AD, Mahavadi S, Kumar DP, Murthy KS. Inhibition of Gαi activity by Gβγ is mediated by PI 3-kinase-γ- and cSrc-dependent tyrosine phosphorylation of Gαi and recruitment of RGS12. Am J Physiol Gastrointest Liver Physiol 2014; 306:G802-10. [PMID: 24578342 PMCID: PMC4010651 DOI: 10.1152/ajpgi.00440.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Others and we have characterized several Gβγ-dependent effectors in smooth muscle, including G protein-coupled receptor kinase 2 (GRK2), PLCβ3, and phosphatidylinositol (PI) 3-kinase-γ, and have identified various signaling targets downstream of PI 3-kinase-γ, including cSrc, integrin-linked kinase, and Rac1-Cdc42/p21-activated kinase/p38 MAP kinase. This study identified a novel mechanism whereby Gβγ acting via PI 3-kinase-γ and cSrc exerts an inhibitory influence on Gαi activity. The Gi2-coupled δ-opioid receptor agonist d-penicillamine (2,5)-enkephalin (DPDPE) activated cSrc, stimulated tyrosine phosphorylation of Gαi2, and induced regulator of G protein signaling 12 (RGS12) association; all three events were blocked by PI 3-kinase (LY294002) and cSrc (PP2) inhibitors and by expression of the COOH-terminal sequence of GRK2-(495-689), a Gβγ-scavenging peptide. Inhibition of forskolin-stimulated cAMP and muscle relaxation by DPDPE was augmented by PP2, LY294002, and a selective PI 3-kinase-γ inhibitor, AS-605420. Expression of tyrosine-deficient (Y69F, Y231F, or Y321F) Gαi2 mutant or knockdown of RGS12 blocked Gαi2 phosphorylation and Gαi2-RGS12 association and caused greater inhibition of cAMP. Parallel studies using somatostatin, cyclopentyl adenosine, or ACh to activate, respectively, Gi1-coupled somatostatin (sstr3) receptors, and Gi3-coupled adenosine A1 or muscarinic m2 receptors elicited cSrc activation, Gαi1 or Gαi3 phosphorylation, Gαi1-RGS12 or Gαi3-RGS12 association, and inhibition of cAMP. Inhibition of cAMP and muscle relaxation was greatly increased by AS-605240 and PP2. The results demonstrate that Gβγ-dependent tyrosine phosphorylation of Gαi1/2/3 by cSrc facilitated recruitment of RGS12, a Gαi-specific RGS protein with a unique phosphotyrosine-binding domain, resulting in rapid deactivation of Gαi and facilitation of smooth muscle relaxation.
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Affiliation(s)
- Jiean Huang
- Department of Physiology and Biophysics, Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Ancy D. Nalli
- Department of Physiology and Biophysics, Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Sunila Mahavadi
- Department of Physiology and Biophysics, Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Divya P. Kumar
- Department of Physiology and Biophysics, Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
| | - Karnam S. Murthy
- Department of Physiology and Biophysics, Program in Enteric Neuromuscular Sciences, Virginia Commonwealth University, Richmond, Virginia
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18
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Al-Qudah M, Anderson CD, Mahavadi S, Bradley ZL, Akbarali HI, Murthy KS, Grider JR. Brain-derived neurotrophic factor enhances cholinergic contraction of longitudinal muscle of rabbit intestine via activation of phospholipase C. Am J Physiol Gastrointest Liver Physiol 2014; 306:G328-37. [PMID: 24356881 PMCID: PMC3920121 DOI: 10.1152/ajpgi.00203.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of proteins best known for its role in neuronal survival, differentiation, migration, and synaptic plasticity in central and peripheral neurons. BDNF is also widely expressed in nonneuronal tissues including the gastrointestinal tract. The role of BDNF in intestinal smooth muscle contractility is not well defined. The aim of this study was to identify the role of BDNF in carbachol (CCh)- and substance P (SP)-induced contraction of intestinal longitudinal smooth muscle. BDNF, selective tropomyosin-related kinase B (TrkB) receptor agonists, and pharmacological inhibitors of signaling pathways were examined for their effects on contraction of rabbit intestinal longitudinal muscle strips induced by CCh and SP. BDNF activation of intracellular signaling pathways was examined by Western blot in homogenates of muscle strips and isolated muscle cells. One-hour preincubation with BDNF enhanced intestinal muscle contraction induced by CCh but not by SP. The selective synthetic TrkB agonists LM 22A4 and 7,8-dihydroxyflavone produced similar effects to BDNF. The Trk antagonist K-252a, a TrkB antibody but not p75NTR antibody, blocked the effect of BDNF. The enhancement of CCh-induced contraction by BDNF was blocked by the phospholipase C (PLC) antagonist U73122, but not by ERK1/2 or Akt antagonists. Direct measurement in muscle strips and isolated muscle cells showed that BDNF caused phosphorylation of TrkB receptors and PLC-γ, but not ERK1/2 or Akt. We conclude that exogenous BDNF augments the CCh-induced contraction of longitudinal muscle from rabbit intestine by activating TrkB receptors and subsequent PLC activation.
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Affiliation(s)
- M. Al-Qudah
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia; ,3Jordan University of Science and Technology, Irbid, Jordan
| | - C. D. Anderson
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - S. Mahavadi
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - Z. L. Bradley
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - H. I. Akbarali
- 2Department of Pharmacology and Toxicology, VCU Program in Enteric Neuromuscular Sciences (VPENS), School of Medicine, Virginia Commonwealth University, Richmond, Virginia; and
| | - K. S. Murthy
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - J. R. Grider
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
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19
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Mahavadi S, Bhattacharya S, Kumar DP, Clay C, Ross G, Akbarali HI, Grider JR, Murthy KS. Increased PDE5 activity and decreased Rho kinase and PKC activities in colonic muscle from caveolin-1-/- mice impair the peristaltic reflex and propulsion. Am J Physiol Gastrointest Liver Physiol 2013; 305:G964-74. [PMID: 24157969 PMCID: PMC3882438 DOI: 10.1152/ajpgi.00165.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Caveolae are specialized regions of the plasma membrane that concentrate receptors and associated signaling molecules critical in regulation of cellular response to transmitters and hormones. We have determined the effects of caveolin-1 (Cav-1) deletion, caveolin-1 siRNA, and caveolar disruption in mice on the signaling pathways that mediate contraction and relaxation in colonic smooth muscle and on the components of the peristaltic reflex in isolated tissue and propulsion in intact colonic segments. In Cav-1-/- mice, both relaxation and contraction were decreased in smooth muscle cells and muscle strips, as well as during both phases of the peristaltic reflex and colonic propulsion. The decrease in relaxation in response to the nitric oxide (NO) donor was accompanied by a decrease in cGMP levels and an increase in phosphodiesterase 5 (PDE5) activity. Relaxation by a PDE5-resistant cGMP analog was not affected in smooth muscle of Cav-1-/- mice, suggesting that inhibition of relaxation was due to augmentation of PDE5 activity. Similar effects on relaxation, PDE5 and cGMP were obtained in muscle cells upon disruption of caveolae by methyl-β-cyclodextrin or suppression of Cav-1. Sustained contraction mediated via inhibition of myosin light chain phosphatase (MLCP) activity is regulated by Rho kinase and PKC via phosphorylation of two endogenous inhibitors of MLCP: myosin phosphatase-targeting subunit (MYPT1) and 17-kDa PKC-potentiated protein phosphatase 1 inhibitor protein (CPI-17), respectively. The activity of both enzymes and phosphorylation of MYPT1 and CPI-17 were decreased in smooth muscle from Cav-1-/- mice. We conclude that the integrity of caveolae is essential for contractile and relaxant activity in colonic smooth muscle and the maintenance of neuromuscular function at organ level.
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Affiliation(s)
- Sunila Mahavadi
- Box 980551, Dept. of Physiology, School of Medicine, Virginia Commonwealth Univ., Richmond, VA 23298-0551.
| | | | | | | | | | - Hamid I. Akbarali
- Departments of 1Physiology and Biophysics, ,2Pharmacology and Toxicology, and ,3Medicine, and VCU Program in Enteric Neuromuscular Science (VPENS), School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - John R. Grider
- Departments of 1Physiology and Biophysics, ,3Medicine, and VCU Program in Enteric Neuromuscular Science (VPENS), School of Medicine, Virginia Commonwealth University, Richmond, Virginia
| | - Karnam S. Murthy
- Departments of 1Physiology and Biophysics, ,3Medicine, and VCU Program in Enteric Neuromuscular Science (VPENS), School of Medicine, Virginia Commonwealth University, Richmond, Virginia
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20
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Al-Shboul O, Mahavadi S, Sriwai W, Grider JR, Murthy KS. Differential expression of multidrug resistance protein 5 and phosphodiesterase 5 and regulation of cGMP levels in phasic and tonic smooth muscle. Am J Physiol Gastrointest Liver Physiol 2013; 305:G314-24. [PMID: 23764893 PMCID: PMC3891211 DOI: 10.1152/ajpgi.00457.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Previous studies have identified differences in the expression of proteins that regulate myosin light chain phosphorylation and contraction in tonic and phasic smooth muscle. cGMP plays a critical role in smooth muscle relaxation and is important for optimal function of phasic and tonic smooth muscle. The intracellular cGMP levels are regulated by its hydrolysis via phosphodiesterase 5 (PDE5) and efflux via novel multidrug resistance protein 5 (MRP5). In the present study we tested the hypothesis that the differences in the phasic and tonic behavior of smooth muscles may be related to differences in mechanisms that terminate cGMP signaling. Expression of PDE5 and MRP5 was significantly (more than 2-fold) higher in fundus compared with antrum. The NO donor S-nitrosoglutathione (GSNO) caused an increase in PDE5 activity and intra- and extracellular cGMP levels in both fundus and antrum. Stimulation of PDE5 activity and increase in extracellular cGMP were significantly higher in fundus, whereas increase in intracellular cGMP was significantly higher in antrum. GSNO-induced increase in extracellular cGMP was blocked in dispersed cells by the cyclic nucleotide export blocker probenecid and in cultured muscle cells by depletion of ATP or suppression of MRP5 by siRNA, providing evidence that cGMP efflux was mediated by ATP-dependent export via MRP5. Consistent with the higher expression and activity levels of PDE5 and MRP5, GSNO-induced PKG activity and muscle relaxation were significantly lower in muscle cells from fundus compared with antrum. Thus higher expression of PDE5 and MRP5 in muscle cells from fundus correlates with tonic phenotype of muscle.
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Affiliation(s)
- Othman Al-Shboul
- Dept. of Physiology and Biophysics, Virginia Commonwealth Univ., Richmond, VA 23298-0711.
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21
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Ahmed R, Mahavadi S, Al-Shboul O, Bhattacharya S, Grider JR, Murthy KS. Characterization of signaling pathways coupled to melatonin receptors in gastrointestinal smooth muscle. ACTA ACUST UNITED AC 2013; 184:96-103. [PMID: 23541890 DOI: 10.1016/j.regpep.2013.03.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 03/06/2013] [Accepted: 03/20/2013] [Indexed: 12/15/2022]
Abstract
Melatonin, a close derivative of serotonin, is involved in physiological regulation of circadian rhythms. In the gastrointestinal (GI) system, melatonin exhibits endocrine, paracrine and autocrine actions and is implicated in the regulation of GI motility. However, it is not known whether melatonin can also act directly on GI smooth muscle cells. The aim of the present study was to determine the expression of melatonin receptors in smooth muscle and identify their signaling pathways. MT1, but not MT2 receptors are expressed in freshly dispersed and cultured gastric smooth muscle cells. Melatonin selectively activated Gq and stimulated phosphoinositide (PI) hydrolysis in freshly dispersed and cultured muscle cells. PI hydrolysis was blocked by the expression of Gq, but not Gi minigene in cultured muscle cells. Melatonin also caused rapid increase in cytosolic Ca(2+) as determined by epifluorescence microscopy in fura-2 loaded single smooth muscle cells, and induced rapid contraction. Melatonin-induced PI hydrolysis and contraction were blocked by a non-selective MT1/MT2 antagonist luzindole (1 μM), but not by a selective MT2 antagonist 4P-PDOT (100 nM), and by the PLC inhibitor U73122. MT2 selective agonist IIK7 (100 nM) had no effect on PI hydrolysis and contraction. We conclude that rabbit gastric smooth muscle cells express melatonin MT1 receptors coupled to Gq. Activation of these receptors causes stimulation of PI hydrolysis and increase in cytosolic Ca(2+), and elicits muscle contraction.
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MESH Headings
- Animals
- Gastrointestinal Tract/metabolism
- Isoindoles/pharmacology
- Muscle Contraction
- Muscle, Smooth/metabolism
- Myocytes, Smooth Muscle/metabolism
- Rabbits
- Receptor, Melatonin, MT1/antagonists & inhibitors
- Receptor, Melatonin, MT1/metabolism
- Receptor, Melatonin, MT2/antagonists & inhibitors
- Receptor, Melatonin, MT2/metabolism
- Signal Transduction
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Affiliation(s)
- Rashad Ahmed
- Department of Physiology and VCU Program in Enteric Neuromuscular Sciences (VPENS), Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, United States
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22
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Baccari MC, Traini C, Garella R, Cipriani G, Vannucchi MG. Relaxin exerts two opposite effects on mechanical activity and nitric oxide synthase expression in the mouse colon. Am J Physiol Endocrinol Metab 2012; 303:E1142-50. [PMID: 22932783 DOI: 10.1152/ajpendo.00260.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The hormone relaxin exerts a variety of functions on the smooth muscle of reproductive and nonreproductive organs, most of which occur through a nitric oxide (NO)-mediated mechanism. In the stomach and ileum, relaxin causes muscle relaxation by modulating the activity and expression of different nitric oxide synthase (NOS) isoforms region-dependently. Nothing is known on the effects of relaxin in the colon, the gut region expressing the highest number of neuronal (n) NOSβ-immunoreactive neurons and mainly involved in motor symptoms of pregnancy and menstrual cycle. Therefore, we studied the effects of relaxin exposure in the mouse proximal colon in vitro evaluating muscle mechanical activity and NOS isoform expression. The functional experiments showed that relaxin decreases muscle tone and increases amplitude of spontaneous contractions; the immunohistochemical results showed that relaxin increases nNOSβ and endothelial (e) NOS expression in the neurons and decreases nNOSα and eNOS expression in the smooth muscle cells (SMC). We hypothesized that, in the colon, relaxin primarily increases the activity and expression of nNOSβ and eNOS in the neurons, causing a reduction of the muscle tone. The downregulation of nNOSα and eNOS expression in the SMC associated with increased muscle contractility could be the consequence of continuous exposue of these cells to the NO of neuronal origin. These findings may help to better understand the physiology of NO in the gastrointestinal tract and the role that the "relaxin-NO" system plays in motor disorders such as functional bowel disease.
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MESH Headings
- Anesthetics, Local/pharmacology
- Animals
- Colon/blood supply
- Colon/cytology
- Colon/innervation
- Colon/metabolism
- Colon, Ascending/cytology
- Colon, Ascending/drug effects
- Colon, Ascending/innervation
- Colon, Ascending/metabolism
- Colon, Transverse/cytology
- Colon, Transverse/drug effects
- Colon, Transverse/innervation
- Colon, Transverse/metabolism
- Enzyme Inhibitors/pharmacology
- Female
- Guanylate Cyclase/antagonists & inhibitors
- In Vitro Techniques
- Interstitial Cells of Cajal/cytology
- Interstitial Cells of Cajal/drug effects
- Interstitial Cells of Cajal/metabolism
- Mechanical Phenomena
- Mice
- Mice, Inbred Strains
- Muscle Contraction/drug effects
- Muscle, Smooth/blood supply
- Muscle, Smooth/cytology
- Muscle, Smooth/innervation
- Muscle, Smooth/metabolism
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/metabolism
- Neurons/cytology
- Neurons/drug effects
- Neurons/metabolism
- Nitric Oxide Donors/pharmacology
- Nitric Oxide Synthase Type I/antagonists & inhibitors
- Nitric Oxide Synthase Type I/metabolism
- Nitric Oxide Synthase Type III/antagonists & inhibitors
- Nitric Oxide Synthase Type III/metabolism
- Osmolar Concentration
- Relaxin/metabolism
- Submucous Plexus/cytology
- Submucous Plexus/drug effects
- Submucous Plexus/metabolism
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Affiliation(s)
- M C Baccari
- Department of Physiological Sciences, University of Florence, Florence, Italy
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23
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Pelletier AM, Venkataramana S, Miller KG, Bennett BM, Nair DG, Lourenssen S, Blennerhassett MG. Neuronal nitric oxide inhibits intestinal smooth muscle growth. Am J Physiol Gastrointest Liver Physiol 2010; 298:G896-907. [PMID: 20338922 DOI: 10.1152/ajpgi.00259.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hyperplasia of smooth muscle contributes to the thickening of the intestinal wall that is characteristic of inflammation, but the mechanisms of growth control are unknown. Nitric oxide (NO) from enteric neurons expressing neuronal NO synthase (nNOS) might normally inhibit intestinal smooth muscle cell (ISMC) growth, and this was tested in vitro. In ISMC from the circular smooth muscle of the adult rat colon, chemical NO donors inhibited [(3)H]thymidine uptake in response to FCS, reducing this to baseline without toxicity. This effect was inhibited by the guanylyl cyclase inhibitor ODQ and potentiated by the phosphodiesterase-5 inhibitor zaprinast. Inhibition was mimicked by 8-bromo (8-Br)-cGMP, and ELISA measurements showed increased levels of cGMP but not cAMP in response to sodium nitroprusside. However, 8-Br-cAMP and cilostamide also showed inhibitory actions, suggesting an additional role for cAMP. Via a coculture model of ISMC and myenteric neurons, immunocytochemistry and image analysis showed that innervation reduced bromodeoxyuridine uptake by ISMC. Specific blockers of nNOS (7-NI, NAAN) significantly increased [(3)H]thymidine uptake in response to a standard stimulus, showing that nNOS activity normally inhibits ISMC growth. In vivo, nNOS axon number was reduced threefold by day 1 of trinitrobenzene sulfonic acid-induced rat colitis, preceding the hyperplasia of ISMC described earlier in this model. We conclude that NO can inhibit ISMC growth primarily via a cGMP-dependent mechanism. Functional evidence that NO derived from nNOS causes inhibition of ISMC growth in vitro predicts that the loss of nNOS expression in colitis contributes to ISMC hyperplasia in vivo.
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Affiliation(s)
- Anne-Marie Pelletier
- Gastrointestinal Diseases Research Unit, Queen's Univ., 76 Stuart St., Kingston, Ontario K7L 2V6
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24
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Casellas D. Methods for imaging Renin-synthesizing, -storing, and -secreting cells. Int J Hypertens 2009; 2010:298747. [PMID: 20948562 PMCID: PMC2949082 DOI: 10.4061/2010/298747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/07/2009] [Accepted: 09/08/2009] [Indexed: 12/04/2022] Open
Abstract
Renin-producing cells have been the object of intense research efforts for the past fifty years within the field of hypertension. Two decades ago, research focused on the concept and characterization of the intrarenal renin-angiotensin system. Early morphological studies led to the concept of the juxtaglomerular apparatus, a minute organ that links tubulovascular structures and function at the single nephron level. The kidney, thus, appears as a highly "topological organ" in which anatomy and function are intimately linked. This point is reflected by a concurrent and constant development of functional and structural approaches. After summarizing our current knowledge about renin cells and their distribution along the renal vascular tree, particularly along glomerular afferent arterioles, we reviewed a variety of imaging techniques that permit a fine characterization of renin synthesis, storage, and release at the single-arteriolar, -cell, or -granule level. Powerful tools such as multiphoton microscopy and transgenesis bear the promises of future developments of the field.
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Affiliation(s)
- Daniel Casellas
- Groupe Rein et Hypertension (EA3127), Institut Universitaire de Recherche Clinique, 641 Avenue du Doyen Giraud, 34093 Montpellier Cédex 5, France
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25
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Flynn RS, Mahavadi S, Murthy KS, Kellum JM, Kuemmerle JF. Insulin-like growth factor-binding protein-5 stimulates growth of human intestinal muscle cells by activation of G{alpha}i3. Am J Physiol Gastrointest Liver Physiol 2009; 297:G1232-8. [PMID: 19808657 PMCID: PMC2850095 DOI: 10.1152/ajpgi.00323.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In human intestinal smooth muscle cells, endogenous insulin-like growth factor-I (IGF-I) regulates growth and IGF-binding protein-5 (IGFBP-5) expression. The effects of IGF-I are facilitated by IGFBP-5. We previously showed that IGFBP-5 acts independently of IGF-I in human intestinal muscle to stimulate proliferation and upregulate IGF-I production by activation of Erk1/2 and p38 MAPK. Thus a positive feedback loop exists between IGF-I and IGFBP-5, whereby both stimulate muscle growth and production of the other factor. In Crohn's disease, IGF-I and IGFBP-5 expression are increased and contribute to stricture formation through this effect on muscle growth. To determine the signaling pathways coupling IGFBP-5 to MAPK activation and growth, smooth muscle cells were isolated from muscularis propria of human intestine and placed into primary culture. Erk1/2 and p38 MAPK activation and type I collagen production were measured by immunoblot. Proliferation was measured by [(3)H]thymidine incorporation. Activation of specific G proteins was measured by ELISA. AG1024, an IGF-I receptor tyrosine kinase inhibitor, was used to isolate the IGF-I-independent effects of IGFBP-5. IGFBP-5-induced phosphorylation of Erk1/2 and p38 MAPK and proliferation were abolished by pertussis toxin, implying the participation of Gi. IGFBP-5 specifically activated Gi3 but not other G proteins. Transfection of an inhibitory Galphai minigene specifically inhibited MAPK activation, proliferation, and both collagen-I and IGF-I production. Our results indicate that endogenous IGFBP-5 activates Gi3 and regulates smooth muscle growth, IGF-I production, and collagen production via the alpha-subunit of Gi3, independently of IGF-I, in normal human intestinal muscle cells.
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Affiliation(s)
| | | | | | - John M. Kellum
- 3Surgery, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
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26
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Hazelgrove KB, Flynn RS, Qiao LY, Grider JR, Kuemmerle JF. Endogenous IGF-I and alpha v beta3 integrin ligands regulate increased smooth muscle growth in TNBS-induced colitis. Am J Physiol Gastrointest Liver Physiol 2009; 296:G1230-7. [PMID: 19359426 PMCID: PMC2697946 DOI: 10.1152/ajpgi.90508.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endogenous insulin-like growth factor-I (IGF-I) regulates intestinal smooth muscle growth by concomitantly stimulating proliferation and inhibiting apoptosis. IGF-I-stimulated growth is augmented by the alpha(v)beta(3) integrin ligands vitronectin and fibronectin. IGF-I expression in smooth muscle is increased in both TNBS-induced colitis and Crohn's disease. We hypothesized that intestinal inflammation increased vitronectin and fibronectin expression by smooth muscle and, along with IGF-I upregulation, increased intestinal muscle growth. Intestinal smooth muscle cells were examined 7 days following the induction of TNBS-induced colitis. Although alpha(v)beta(3) integrin expression was not altered by TNBS-induced colitis, vitronectin and fibronectin levels were increased by 80 +/- 10% and 90 +/- 15%, above control levels, respectively. Basal IGF-I receptor phosphorylation in inflamed muscle from TNBS-treated rats was increased by 86 +/- 8% over vehicle-treated controls. Basal ERK1/2, p70S6 kinase, and GSK-3beta phosphorylation in muscle cells of TNBS-treated rats were also increased by 140-180%. TNBS treatment increased basal muscle cell proliferation by 130 +/- 15% and decreased apoptosis by 20 +/- 2% compared with that in vehicle-treated controls. The changes in proliferation and apoptosis were reversed by an IGF-I receptor tyrosine kinase inhibitor or an alpha(v)beta(3) integrin antagonist. The results suggest that smooth muscle hyperplasia in TNBS-induced colitis partly results from the upregulation of endogenous IGF-I and ligands of alpha(v)beta(3) integrin that mediate increased smooth muscle cell proliferation and decreased apoptosis. This paper has identified one mechanism regulating smooth muscle hyperplasia, a feature of stricture formation that occurs in the chronically inflamed intestine of TNBS-induced colitis and potentially Crohn's disease.
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Affiliation(s)
- Krystina B. Hazelgrove
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | - Robert S. Flynn
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | - Li-Ya Qiao
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | - John R. Grider
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | - John F. Kuemmerle
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
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27
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Patel BA, Galligan JJ, Swain GM, Bian X. Electrochemical monitoring of nitric oxide released by myenteric neurons of the guinea pig ileum. Neurogastroenterol Motil 2008; 20:1243-50. [PMID: 18694441 PMCID: PMC2585606 DOI: 10.1111/j.1365-2982.2008.01177.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nitric oxide (NO) released by myenteric neurons in isolated segments of guinea pig ileum was monitored in vitro using continuous amperometry. NO was detected as an oxidation current recorded with a boron-doped diamond microelectrode held at 1 V vs a Ag|AgCl reference electrode. This potential was sufficient to oxidize NO. Longitudinal muscle-myenteric plexus (LMMP) and circular muscle strip preparations were used. In the LMMP preparation, NO release was evoked by superfusion of 1 mumol L(-1) nicotine, which activates nicotinic acetylcholine receptors expressed by myenteric neurons and myenteric nerve endings. The oxidation current was ascribed to NO based on the following observations: (i) no response was detected at less positive potentials (0.75 V) at which only catecholamines and biogenic amines are oxidized, (ii) the current was abolished in the presence of the nitric oxide synthase antagonist, N-nitro-l-arginine (l-NNA) and (iii) oxidation currents were attenuated by addition of the NO scavenger, myoglobin, to the superfusing solution. In the LMMP preparation, stimulated release produced a maximum current that corresponded nominally to 46 nmol L(-1) of NO. The oxidation currents decreased to 10 and 2 nmol L(-1), respectively, when the tissue was perfused with tetrodotoxin and l-NNA. Oxidation currents recorded from circular muscle strips (stimulated using nicotine) were threefold larger than those recorded from the LMMP. This study shows that NO release can be detected from various in vitro preparations of the guinea pig ileum using real-time electroanalytical techniques.
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Affiliation(s)
- Bhavik Anil Patel
- Department of Bioengineering, Imperial College London, London, SW7 2AZ,Department of Chemistry, Michigan State University, East Lansing, MI 48824
| | - James J. Galligan
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824,Neuroscience Program, Michigan State University, East Lansing, MI 48824
| | - Greg M. Swain
- Department of Chemistry, Michigan State University, East Lansing, MI 48824,Neuroscience Program, Michigan State University, East Lansing, MI 48824
| | - Xiaochun Bian
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824,Neuroscience Program, Michigan State University, East Lansing, MI 48824
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28
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Autoinhibition of endothelial nitric oxide synthase (eNOS) in gut smooth muscle by nitric oxide. ACTA ACUST UNITED AC 2008; 151:75-9. [PMID: 18926858 DOI: 10.1016/j.regpep.2008.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 09/05/2008] [Accepted: 09/20/2008] [Indexed: 11/22/2022]
Abstract
Nitric oxide in the gut is produced by nNOS in enteric neurons and by eNOS in smooth muscle cells. The eNOS in smooth muscle is activated by vasoactive intestinal peptide (VIP) released from enteric neurons. In the present study, we examined the effect of nitric oxide on VIP-induced eNOS activation in smooth muscle cells isolated from human intestine and rabbit stomach. NOS activity was measured as formation of the 1:1 co-product, l-citrulline from l-arginine. VIP caused an increase in l-citrulline production that was inhibited by NO in a concentration dependent manner (IC(50)~25 microM; maximal inhibition 72% at 100 microM NO). Basal l-citrulline production, however, was unaffected by NO. The effect was not mediated by cGMP/PKG since the PKG inhibitor KT5823 had no effect on eNOS autoinhibition. The autoinhibition was selective for NO since the co-product l-citrulline had no effect on VIP-induced NOS activation. Similar effects were obtained in rabbit gastric and human intestinal smooth muscle cells. The results suggest that NO produced in smooth muscle cells as a result of the activation of eNOS by VIP exerts an autoinhibitory restraint on eNOS thereby regulating the balance of the VIP/cAMP/PKA and NO/cGMP/PKG pathways that regulate the relaxation of gut smooth muscle.
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29
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Fornai M, Colucci R, Antonioli L, Crema F, Buccianti P, Chiarugi M, Baschiera F, Ghisu N, Tuccori M, Blandizzi C, Del Tacca M. Cholecystokinin CCK2 receptors mediate the peptide's inhibitory actions on the contractile activity of human distal colon via the nitric oxide pathway. Br J Pharmacol 2007; 151:1246-53. [PMID: 17572695 PMCID: PMC2189827 DOI: 10.1038/sj.bjp.0707339] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Cholecystokinin is known to exert stimulant actions on intestinal motility via activation of type 1 cholecystokinin receptors (CCK(1)). However, the role played by cholecystokinin 2 (CCK(2)) receptors in the regulation of gut motility remains undetermined. This study was designed to examine the influence of CCK(2) receptors on the contractile activity of human distal colon. EXPERIMENTAL APPROACH The effects of compounds acting on CCK(2) receptors were assessed in vitro on motor activity of longitudinal smooth muscle, under basal conditions as well as in the presence of KCl-induced contractions or transmural electrical stimulation. KEY RESULTS Cholecystokinin octapeptide sulphate induced concentration-dependent contractions which were enhanced by GV150013 (CCK(2) receptor antagonist; +57% at 0.01 microM). These effects were unaffected by tetrodotoxin. The enhancing actions of GV150013 on contractions evoked by cholecystokinin octapeptide sulphate were unaffected by N(omega)-propyl-L-arginine (NPA, neuronal nitric oxide synthase inhibitor), while they were prevented by N(omega)-nitro-L-arginine methylester (L-NAME, non-selective nitric oxide synthase inhibitor). In the presence of KCl-induced contractions, cholecystokinin octapeptide sulphate elicited concentration-dependent relaxations (-36%), which were unaffected by NPA, but were counteracted by GV150013 or L-NAME. The application of electrical stimuli evoked phasic contractions which were enhanced by GV150013 (+41 % at 0.01 microM). CONCLUSIONS AND IMPLICATIONS CCK(2) receptors mediate inhibitory actions of cholecystokinin on motor activity of human distal colon. It is suggested that CCK(2) receptors exert their modulating actions through a nitric oxide pathway, independent of the activity of the neuronal nitric oxide synthase isoform.
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Affiliation(s)
- M Fornai
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - R Colucci
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - L Antonioli
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - F Crema
- Department of Internal Medicine and Therapeutics, University of Pavia Pavia, Italy
| | - P Buccianti
- Department of Surgery, University of Pisa Pisa, Italy
| | - M Chiarugi
- Department of Surgery, University of Pisa Pisa, Italy
| | - F Baschiera
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - N Ghisu
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - M Tuccori
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
| | - C Blandizzi
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
- Author for correspondence:
| | - M Del Tacca
- Division of Pharmacology and Chemotherapy, Department of Internal Medicine, University of Pisa Pisa, Italy
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30
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Dogan I, Bhargava V, Liu J, Mittal RK. Axial stretch: A novel mechanism of the lower esophageal sphincter relaxation. Am J Physiol Gastrointest Liver Physiol 2007; 292:G329-34. [PMID: 17023549 DOI: 10.1152/ajpgi.00351.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Swallow and esophageal distension-induced relaxations of the lower esophageal sphincter (LES) are associated with an orad movement of the LES because of a concurrent esophageal longitudinal muscle contraction. We hypothesized that the esophageal longitudinal muscle contraction induces a cranially directed mechanical stretch on the LES and therefore studied the effects of a mechanical stretch on the LES pressure. In adult opossums, a silicon tube was placed via mouth into the esophagus and laparotomy was performed. Two needles with silk sutures were passed, 90 degrees apart, through the esophageal walls and silicon tube, 2 cm above the LES. The tube was withdrawn, and one end of each of the four sutures was anchored to the esophageal wall and the other end exited through the mouth to exert graded cranially directed stretch on the LES by using pulley and weights. A cranially directed stretch caused LES relaxation, and with the cessation of stretch there was recovery of the LES pressure. The degree an d duration of LES relaxation increased with the weight and the duration of stretch, respectively. The mean LES relaxation in all animals was 77.7 +/- 4.7%. The required weight to induce maximal LES relaxation differed in animals (714 +/- 348 g). N(G)-nitro-L-arginine, a nitric oxide inhibitor, blocked the axial stretch-induced LES relaxation almost completely (from 78 to 19%). Our data support the presence of an axial stretch-activated inhibitory mechanism in the LES. The role of axial stretch in the LES relaxation induced by swallow and esophageal distension requires further investigation.
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Affiliation(s)
- Ibrahim Dogan
- Division of Gastroenterology, San Diego VA HealthCare System, 3350 La Jolla Village Dr., San Diego, CA 92161, USA
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31
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Huang N, Khan A, Ashrafpour H, Neligan PC, Forrest CR, Kontos CD, Pang CY. Efficacy and mechanism of adenovirus-mediated VEGF-165 gene therapy for augmentation of skin flap viability. Am J Physiol Heart Circ Physiol 2006; 291:H127-37. [PMID: 16461370 DOI: 10.1152/ajpheart.01253.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skin ischemic necrosis due to vasospasm and/or insufficient vascularity is the most common complication in the distal portion of the skin flap in reconstructive surgery. This project was designed to test our hypothesis that preoperative subdermal injection of adenoviral vectors encoding genes for vascular endothelial growth factor-165 (Ad.VEGF-165) or endothelial nitric oxide (NO) synthase (Ad.eNOS) effectively augments skin viability in skin flap surgery and that the mechanism of Ad.VEGF-165 gene therapy involves an increase in synthesis/release of the angiogenic and vasodilator factor NO. PBS (0.5 ml) or PBS containing Ad.VEGF-165, Ad.eNOS, or adenovirus (Ad.Null) was injected subdermally into the distal half of a mapped rat dorsal skin flap (4 × 10 cm) 7 days preoperatively, and skin flap viability was assessed 7 days postoperatively. Local subdermal gene therapy with 2 × 107–2 × 1010 plaque-forming units of VEGF-165 increased skin flap viability compared with PBS- or Ad.Null-injected control ( P < 0.05). Subdermal Ad.VEGF-165 and Ad.eNOS gene therapies were equally effective in increasing skin flap viability at 5 × 108 plaque-forming units. Subdermal Ad.VEGF-165 therapy was associated with upregulation of eNOS protein expression, Ca2+-dependent NOS activity, synthesis/release of NO, and increase in capillary density and blood flow in the distal portion of the skin flap. Injection of the NOS inhibitor Nω-nitro-l-arginine (15 mg/kg im), but not the cyclooxygenase inhibitor indomethacin (5 mg/kg im), 45 min preoperatively completely abolished the increase in skin flap blood flow and viability induced by Ad.VEGF-165 injected subdermally into the mapped skin flap 7 days preoperatively. We have demonstrated for the first time that 1) Ad.VEGF-165 and Ad.eNOS mapped skin flap injected subdermally into the mapped skin flap 7 days preoperatively are equally effective in augmenting viability in the rat dorsal skin flap compared with control, 2) the mechanism of subdermal Ad.VEGF-165 gene therapy in augmenting skin flap viability involves an increase in NO synthesis/release downstream of upregulation of eNOS protein expression and Ca2+-dependent NOS activity, and 3) the vasodilating effect of NO may predominantly mediate subdermal Ad.VEGF gene therapy in augmenting skin flap blood flow and viability.
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Affiliation(s)
- Ning Huang
- Research Institute, The Hospital for Sick Children; Department of Surgery, University of Toronto, Toronto, ON, Canada M5G 1X8
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Abstract
Phosphorylation of Ser19 on the 20-kDa regulatory light chain of myosin II (MLC20) by Ca2+/calmodulin-dependent myosin light-chain kinase (MLCK) is essential for initiation of smooth muscle contraction. The initial [Ca2+]i transient is rapidly dissipated and MLCK inactivated, whereas MLC20 and muscle contraction are well maintained. Sustained contraction does not reflect Ca2+ sensitization because complete inhibition of MLC phosphatase activity in the absence of Ca2+ induces smooth muscle contraction. This contraction is suppressed by staurosporine, implying participation of a Ca2+-independent MLCK. Thus, sustained contraction, as with agonist-induced contraction at experimentally fixed Ca2+ concentrations, involves (a) G protein activation, (b) regulated inhibition of MLC phosphatase, and (c) MLC20 phosphorylation via a Ca2+-independent MLCK. The pathways that lead to inhibition of MLC phosphatase by G(q/13)-coupled receptors are initiated by sequential activation of Galpha(q)/alpha13, RhoGEF, and RhoA, and involve Rho kinase-mediated phosphorylation of the regulatory subunit of MLC phosphatase (MYPT1) and/or PKC-mediated phosphorylation of CPI-17, an endogenous inhibitor of MLC phosphatase. Sustained MLC20 phosphorylation is probably induced by the Ca2+-independent MLCK, ZIP kinase. The pathways initiated by G(i)-coupled receptors involve sequential activation of Gbetagamma(i), PI 3-kinase, and the Ca2+-independent MLCK, integrin-linked kinase. The last phosphorylates MLC20 directly and inhibits MLC phosphatase by phosphorylating CPI-17. PKA and PKG, which mediate relaxation, act upstream to desensitize the receptors (VPAC2 and NPR-C), inhibit adenylyl and guanylyl cyclase activities, and stimulate cAMP-specific PDE3 and PDE4 and cGMP-specific PDE5 activities. These kinases also act downstream to inhibit (a) initial contraction by inhibiting Ca2+ mobilization and (b) sustained contraction by inhibiting RhoA and targets downstream of RhoA. This increases MLC phosphatase activity and induces MLC20 dephosphorylation and muscle relaxation.
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Affiliation(s)
- Karnam S Murthy
- Department of Physiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA.
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Kuemmerle JF. Occupation of alphavbeta3-integrin by endogenous ligands modulates IGF-I receptor activation and proliferation of human intestinal smooth muscle. Am J Physiol Gastrointest Liver Physiol 2006; 290:G1194-202. [PMID: 16195423 DOI: 10.1152/ajpgi.00345.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously shown that endogenous IGF-I regulates growth of human intestinal smooth muscle cells by stimulating proliferation and inhibiting apoptosis. In active Crohn's disease, expression of IGF-I and the alpha(v)beta(3)-integrin receptor ligands fibronectin and vitronectin is increased. The aim of the present study was to determine whether occupation of the alpha(v)beta(3)-receptor influences IGF-I receptor tyrosine kinase activation and function in human intestinal smooth muscle cells. In untreated cells, IGF-I elicited time-dependent tyrosine phosphorylation of its cognate receptor that was maximal within 2 min and sustained for 30 min. In the presence of the alpha(v)beta(3)-ligand fibronectin, IGF-I-stimulated IGF-I receptor activation was augmented. Conversely, in the presence of the alpha(v)beta(3)-specific disintegrin echistatin, IGF-I-stimulated IGF-I receptor tyrosine kinase phosphorylation was inhibited. IGF-I-stimulated IGF-I receptor activation was accompanied by recruitment of the adapter protein IRS-1, activation of Erk1/2, p70S6 kinase, and proliferation. These effects were augmented by fibronectin and attenuated by echistatin. IGF-I also elicited time-dependent recruitment of protein tyrosine phosphatase SHP-2 that coincided with dephosphorylation of the tyrosine phosphorylated IGF-I receptor tyrosine kinase. The alpha(v)beta(3)-disintegrin echistatin accelerated the rate of SHP-2 recruitment and deactivation of the IGF-I receptor tyrosine kinase. The results show that occupancy of the alpha(v)beta(3)-integrin receptor modulates IGF-I-induced IGF-I receptor activation and function in human intestinal muscle cells. We hypothesize that the concomitant increases in the expression of alpha(v)beta(3)-ligands and of IGF-I in active Crohn's disease may contribute to muscle hyperplasia and stricture formation by acting in concert to augment IGF-I-stimulated IGF-I receptor tyrosine kinase activity and IGF-I-mediated muscle cell growth.
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Affiliation(s)
- John F Kuemmerle
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, 23298-0341, USA.
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Kuemmerle JF. Endogenous IGF-I protects human intestinal smooth muscle cells from apoptosis by regulation of GSK-3 beta activity. Am J Physiol Gastrointest Liver Physiol 2005; 288:G101-10. [PMID: 15297258 DOI: 10.1152/ajpgi.00032.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously shown that endogenous IGF-I regulates human intestinal smooth muscle cell proliferation by activation of phosphatidylinositol 3 (PI3)-kinase- and Erk1/2-dependent pathways that jointly regulate cell cycle progression and cell division. Whereas insulin-like growth factor-I (IGF-I) stimulates PI3-kinase-dependent activation of Akt, expression of a kinase-inactive Akt did not alter IGF-I-stimulated proliferation. In other cell types, Akt-dependent phosphorylation of glycogen synthase kinase-3 beta (GSK-3 beta) inhibits its activity and its ability to stimulate apoptosis. The aim of the present study was to determine whether endogenous IGF-I regulates Akt-dependent GSK-3 beta phosphorylation and activity and whether it regulates apoptosis in human intestinal muscle cells. IGF-I elicited time- and concentration-dependent GSK-3 beta phosphorylation (inactivation) that was measured by Western blot analysis using a phospho-specific GSK-3beta antibody. Endogenous IGF-I stimulated GSK-3 beta phosphorylation and inhibited GSK-3 beta activity (measured by in vitro kinase assay) in these cells. IGF-I-dependent GSK-3 beta phosphorylation and the resulting GSK-3 beta inactivation were mediated by activation of a PI3-kinase-dependent, phosphoinositide-dependent kinase-1 (PDK-1)-dependent, and Akt-dependent mechanism. Deprivation of serum induced beta-catenin phosphorylation, increased in caspase 3 activity, and induced apoptosis of muscle cells, which was inhibited by either IGF-I or a GSK-3 beta inhibitor. Endogenous IGF-I inhibited beta-catenin phosphorylation, caspase 3 activation, and apoptosis induced by serum deprivation. IGF-I-dependent inhibition of apoptosis, similar to GSK-3 beta activity, was mediated by a PI3-kinase-, PDK-1-, and Akt-dependent mechanism. We conclude that endogenous IGF-I exerts two distinct but complementary effects on intestinal smooth muscle cell growth: it stimulates proliferation and inhibits apoptosis. The growth of intestinal smooth muscle cells is regulated jointly by the net effect of these two processes.
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Affiliation(s)
- John F Kuemmerle
- Division of Gastroenterology, Medical College of Virginia Campus, Virginia Commonwealth University, PO Box 980711, Richmond, VA 23298-0711, USA.
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Khan A, Ashrafpour H, Huang N, Neligan PC, Kontos C, Zhong A, Forrest CR, Pang CY. Acute local subcutaneous VEGF165 injection for augmentation of skin flap viability: efficacy and mechanism. Am J Physiol Regul Integr Comp Physiol 2004; 287:R1219-29. [PMID: 15217788 DOI: 10.1152/ajpregu.00143.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Distal skin ischemic necrosis is a common complication in skin flap surgery. The pathogenesis of skin flap ischemic necrosis is unclear, and there is no clinical treatment available. Here, we used the 4 × 10 cm rat dorsal skin flap model to test our hypothesis that subcutaneous injection of vascular endothelial growth factor 165 (VEGF165) in skin flaps at the time of surgery is effective in augmentation of skin flap viability, which is associated with an increase in nitric oxide (NO) production, and the mechanism involves 1) an increase in skin flap blood flow in the early stage after surgery and 2) enhanced angiogenesis subsequently to sustain increased skin flap blood flow and viability. We observed that subcutaneous injection of VEGF165 in skin flaps at the time of surgery increased skin flap viability in a dose-dependant manner. Subcutaneous injection of VEGF165 at the dose of 2 μg/flap increased skin flap viability by 28% ( P < 0.05; n = 8). Over 80% of this effect was blocked by intramuscular injection of the NO synthase (NOS) inhibitor Nω-nitro-l-arginine (13 mg/kg) 45 min before surgery ( P < 0.05; n = 8). The VEGF165 treatment also increased skin flap blood flow (2.68 ± 0.63 ml·min−1·100 g−1) compared with the control (1.26 ± 0.10 ml·min−1·100 g−1; P < 0.05, n = 6) assessed 6 h postoperatively. There was no change in skin flap capillary density at this time point. VEGF165-induced increase in capillary density (32.2 ± 1.1 capillaries/mm2; P < 0.05, n = 7) compared with control (24.6 ± 1.4 capillaries/mm2) was seen 7 days postoperatively. There was also evidence to indicate that VEGF165-induced NO production in skin flaps was stimulated by activation of NOS activity followed by upregulation of NOS protein expression. These observations support our hypothesis and for the first time provide an important insight into the mechanism of acute local VEGF165 protein therapy in mitigation of skin flap ischemic necrosis.
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Affiliation(s)
- Asim Khan
- Research Institute, The Hospital for Sick Children, University of Toronto, Ontario, Canada M5G 1X8
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Hersch E, Huang J, Grider JR, Murthy KS. Gq/G13signaling by ET-1 in smooth muscle: MYPT1 phosphorylation via ETAand CPI-17 dephosphorylation via ETB. Am J Physiol Cell Physiol 2004; 287:C1209-18. [PMID: 15475516 DOI: 10.1152/ajpcell.00198.2004] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We analyzed the signaling pathways initiated by endothelin receptors ETAand ETBin intestinal circular and longitudinal smooth muscle cells. The response to endothelin-1 (ET-1) consisted of two phases in both cell types. The initial, transient phase of contraction and phosphorylation of 20-kDa myosin light chain (MLC20) was mediated additively by ETAand ETBreceptors and initiated by Gαq-, Ca2+/calmodulin-dependent activation of MLC kinase. In contrast, the sustained phase was mediated selectively by ETAreceptors via a pathway involving sequential activation of Gα13, RhoA, and Rho kinase, resulting in phosphorylation of MYPT1 at Thr696and phosphorylation of MLC20. Although PKC was activated, CPI-17 was not phosphorylated and hence did not contribute to inhibition of MLC phosphatase. The absence of CPI-17 phosphorylation by PKC reflected active dephosphorylation of CPI-17 by protein phosphatase 2A (PP2A). PP2A was activated via a pathway involving ETB-dependent stimulation of p38 MAPK activity. CPI-17 phosphorylation was unmasked in the presence of the ETBantagonist BQ-788, but not the ETAantagonist BQ-123, and in the presence of a low concentration of okadaic acid, which selectively inactivates PP2A. The resultant phosphorylation of CPI-17 was blocked by bisindolylmaleimide, providing direct confirmation that it was PKC dependent. We conclude that the two phases of the intestinal smooth muscle response to ET-1 involve distinct receptors, G proteins, and signaling pathways. The sustained response is mediated via selective ETA-dependent phosphorylation of MYPT1. In contrast, ETBinitiates an inhibitory pathway involving p38 MAPK-dependent activation of PP2A that causes dephosphorylation of CPI-17.
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Affiliation(s)
- Eric Hersch
- Department of Physiology, Virginia Commonwealth University Medical School, Richmond, Virginia 23298, USA
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Kuemmerle JF, Murthy KS, Bowers JG. IGFBP-3 activates TGF-beta receptors and directly inhibits growth in human intestinal smooth muscle cells. Am J Physiol Gastrointest Liver Physiol 2004; 287:G795-802. [PMID: 15178549 DOI: 10.1152/ajpgi.00009.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have shown that human intestinal smooth muscle cells produce IGF-I and IGF binding protein-3 (IGFBP-3). Endogenous IGF-I acts in autocrine fashion to stimulate growth of these cells. IGFBP-3 inhibits the binding of IGF-I to its receptor and thereby inhibits IGF-I-stimulated growth. In several carcinoma cell lines and some normal cells, IGFBP-3 regulates growth independently of IGF-I. Two mechanisms for this effect have been identified: IGFBP-3 can directly activate transforming growth factor-beta (TGF-beta) receptors or it can undergo direct nuclear translocation. The aim of the present study was to determine whether IGFBP-3 acts independently of IGF-I and to characterize the mechanisms mediating this effect in human intestinal smooth muscle cells. The direct effects of IGFBP-3 were determined in the presence of an IGF-I receptor antagonist to eliminate its IGF-I-dependent effects. Affinity labeling of TGF-beta receptors (TGF-betaRI, TGF-betaRII, and TGF-betaRV) with 125I-labeled TGF-beta1 showed that IGFBP-3 displaced binding to TGF-betaRII and TGF-betaRV in a concentration-dependent fashion. IGFBP-3 stimulated TGF-betaRII-dependent serine phosphorylation (activation) of both TGF-betaRI and of its primary substrate, Smad2(Ser465/467). IGFBP-3 also caused IGF-I-independent inhibition of basal [3H]thymidine incorporation. The effects of IGFBP-3 on Smad2 phosphorylation and on smooth muscle cell proliferation were independent of TGF-beta1 and were abolished by transfection of Smad2 siRNA. Immunoneutralization of IGFBP-3 increased basal [3H]thymidine incorporation, implying that endogenous IGFBP-3 inhibits proliferation. We conclude that endogenous IGFBP-3 directly inhibits proliferation of human intestinal smooth muscle cells by activation of TGF-betaRI and Smad2, an effect that is independent of its effect on IGF-I-stimulated growth.
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Affiliation(s)
- John F Kuemmerle
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298-0711, USA.
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38
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Kuemmerle JF, Zhou H, Bowers JG. IGF-I stimulates human intestinal smooth muscle cell growth by regulation of G1 phase cell cycle proteins. Am J Physiol Gastrointest Liver Physiol 2004; 286:G412-9. [PMID: 14592948 DOI: 10.1152/ajpgi.00403.2003] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Autocrine production of insulin-like growth factor-I (IGF-I) regulates growth of human intestinal muscle cells by activation of distinct phosphatidylinositol 3-kinase (PI3-kinase)-dependent and ERK1/2-dependent pathways. The aim of the present study was to determine the mechanisms by which IGF-I regulates the G(1) phase of the cell cycle and muscle cell proliferation. Incubation of quiescent cells with IGF-I stimulated time-dependent cell cycle progression measured by using fluorescence-activated cell sorting analysis and by incorporation of [(3)H]thymidine. Studies using a microarray-based approach were used initially to identify genes expressed in human intestinal muscle encoding proteins known to participate in the G(1) phase of the cell cycle that were regulated by IGF-I. Incubation of muscle cells for 24 h with IGF-I elicited greater than fivefold increase in the expression of cyclin D1 and greater than twofold increase in retinoblastoma protein (Rb1). IGF-I elicited a time-dependent increase in cyclin D1 protein levels mediated jointly by ERK1/2-dependent and PI3-kinase-dependent mechanisms. Increase in cyclin D1 levels was accompanied by a time-dependent increase in cyclin D1-dependent cyclin-dependent kinase-4 (CDK4) activity. IGF-I also elicited a rapid time-dependent increase in Rb-(Ser807/811) phosphorylation, the specific target of the cyclin D(1)-dependent CDK4 kinase, and a slower increase in total Rb protein levels. We conclude that IGF-I stimulates G(1) phase progression, DNA synthesis, and cell proliferation of human intestinal smooth muscle cells. Effects of IGF-I on proliferation are mediated jointly by ERK1/2-dependent and PI3-kinase-dependent pathways that regulate cyclin D1 levels, CDK4 activity, and Rb activity.
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Affiliation(s)
- John F Kuemmerle
- Department of Medicine, Medical College of Virginia Campus, Virginia Commonwealth University, PO Box 980711, Richmond, VA 23298-0711, USA.
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Fountain SJ, Cheong A, Flemming R, Mair L, Sivaprasadarao A, Beech DJ. Functional up-regulation of KCNA gene family expression in murine mesenteric resistance artery smooth muscle. J Physiol 2004; 556:29-42. [PMID: 14742730 PMCID: PMC1664901 DOI: 10.1113/jphysiol.2003.058594] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study focused on the hypothesis that KCNA genes (which encode K(V)alpha1 voltage-gated K(+) channels) have enhanced functional expression in smooth muscle cells of a primary determinant of peripheral resistance - the small mesenteric artery. Real-time PCR methodology was developed to measure cell type-specific in situ gene expression. Profiles were determined for arterial myocyte expression of RNA species encoding K(V)alpha1 subunits as well as K(V)beta1, K(V)alpha2.1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Ca)beta1. The seven major KCNA genes were expressed and more readily detected in endothelium-denuded mesenteric resistance artery compared with thoracic aorta; quantification revealed dramatic differential expression of one to two orders of magnitude. There was also four times more RNA encoding K(V)alpha2.1 but less or similar amounts encoding K(V)beta1, K(V)gamma9.3, BK(Ca)alpha1 and BK(Cabeta)1. Patch-clamp recordings from freshly isolated smooth muscle cells revealed dominant K(V)alpha1 K(+) current and current density twice as large in mesenteric cells. Therefore, we suggest the increased RNA production of the resistance artery impacts on physiological function, although there is quantitatively less K(+) current than might be expected. The mechanism conferring up-regulated expression of KCNA genes may be common to all the gene family and play a functional role in the physiological control of blood pressure.
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Affiliation(s)
- S J Fountain
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
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Quintana E, Hernández C, Alvarez-Barrientos A, Esplugues JV, Barrachina MD. Synthesis of nitric oxide in post‐ganglionic myenteric neurons during endotoxemia: implications for gastric motor function. FASEB J 2004; 18:531-3. [PMID: 14715697 DOI: 10.1096/fj.03-0596fje] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have investigated the mechanisms underlying acute changes in gastric motor function triggered by endotoxemia. In fundal strips from rats pre-treated with endotoxin (40 microg/kg, i.p. 30 min), mechanical activity was analyzed and the source of nitric oxide (NO) was visualized by confocal microscopy of tissue loaded with the fluorescent dye DAF-FM. NOS expression was determined by quantitative RT-PCR and Western blot, and enzyme activity by the citrulline assay. Strips from endotoxin-treated rats were hypo-contractile. This was prevented by pre-incubation with the neurotoxin tetrodotoxin, the gangliar blocker hexamethonium, or non-selective and neuronal-specific NOS inhibitors (L-NOARG and TRIM, respectively). The soluble guanylyl cyclase (sGC) inhibitor ODQ and the inhibitor of small conductance Ca2+-activated K+ channels apamin prevented relaxation induced by endotoxin, nicotine, exogenous NO (DETA-NONOate), and the NO-independent sGC activator BAY 41-2272. NO synthesis was observed in neuronal soma, axons, and nerve endings of the myenteric plexus in the fundus of endotoxin-treated rats and was prevented by L-NAME, tetrodotoxin, and hexamethonium. nNOS and iNOS mRNA and protein contents were unchanged. Our findings demonstrate synthesis of NO in post-ganglionic myenteric neurons during early endotoxemia that mediates gastric hypo-contractility. The effect of NO is mediated via sGC and small conductance Ca2+-activated K+channels.
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Affiliation(s)
- Elsa Quintana
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
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Banwait KS, Rattan S. Role of nitric oxide in beta3-adrenoceptor activation on basal tone of internal anal sphincter. Am J Physiol Gastrointest Liver Physiol 2003; 285:G547-55. [PMID: 12736154 DOI: 10.1152/ajpgi.00545.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Effects of activation of beta3-adrenoceptor (beta3-AR) have not been determined in the spontaneously tonic smooth muscle of the internal anal sphincter (IAS). The effects of disodium (R,R)-5-[2-[2-3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]-1,3-benzodioxole-2,2-dicarboxylate (CL 316243), a selective beta3-AR agonist, on the basal smooth muscle tone and direct release of nitric oxide (NO) by circular smooth muscle strips of the opossum IAS were determined. We also examined the presence of endothelial nitric oxide synthase (eNOS) protein by Western blot studies. CL 316243 produced a concentration-dependent relaxation of the smooth muscle that remained unmodified by different neurohumoral antagonists. The smooth muscle relaxation by CL 316243 was selectively antagonized by L 748337, a beta3-AR antagonist. Such relaxation was several times longer than by isoproterenol. The effect of CL 316243 was significantly attenuated by a nonselective NOS inhibitor N(omega)-nitro-l-arginine (l-NNA) and by putative inhibitor of eNOS l-N5-(1-iminoethyl)-ornithine dihydrochloride (l-NIO). Inhibitors of iNOS [N-(3-aminomethyl)benzyl acetamide 2HCl] and nNOS [1-[2-(trifluoromethylphenyl)imidazole]] had no effect on this relaxation. Relaxation of the IAS smooth muscle induced by CL 316243 was accompanied by an increased release of NO; this was attenuated by l-NNA and l-NIO. In addition, Western blot studies revealed the presence of eNOS in the circular smooth muscle of the IAS. These data demonstrate potent and protracted IAS smooth muscle relaxation by beta3-AR activation, which is partly transduced via NOS, possibly smooth muscle eNOS. Multiple signal-transduction pathways including NOS activation may explain the characteristic IAS relaxation by beta3-AR activation. The studies may have therapeutic implications in anorectal motility disorders.
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Affiliation(s)
- Kuldip S Banwait
- Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
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42
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Zhou H, Murthy KS. Identification of the G protein-activating sequence of the single-transmembrane natriuretic peptide receptor C (NPR-C). Am J Physiol Cell Physiol 2003; 284:C1255-61. [PMID: 12676657 DOI: 10.1152/ajpcell.00520.2002] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rat natriuretic peptide clearance receptor (NPR-C) contains four sequences capable of inhibiting adenylyl cyclase. We have undertaken mutational and deletion studies on the intracellular domain of rat NPR-C to determine which of these sequences is functionally relevant. Nine mutant receptors were constructed by deletion of 11 or 28 COOH-terminal residues or by site-directed mutagenesis of basic residues in a 17-amino acid sequence, R(469)RNHQEESNIGKHRELR(485), corresponding to the main active peptide. Substitution of arginine residues (R(469)R(470)) flanking the NH(2) terminus abolished G(i1) and G(i2) and PLC-beta activities and inhibition of adenylyl cyclase. Substitution of one or two basic residues (H(481) and/or R(482) or R(485)) in the COOH-terminal motif (H(481)RELR(485)) greatly decreased or abolished G protein and PLC-beta activities and inhibition of adenylyl cyclase. This implies that sequences NH(2)-terminal to the motif or COOH-terminal to R(470) could not sustain receptor activity in situ, although they exhibited activity when used as synthetic peptides. Deletion of the 11 COOH-terminal residues (E(486) to A(496)) suggested an autoinhibitory function for this sequence. We conclude that the 17-amino acid sequence (R(469) to R(485)) in the middle region of the intracellular domain of NPR-C is both necessary and sufficient for activation of G proteins and effector enzymes.
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Affiliation(s)
- Huiping Zhou
- Department of Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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Kuemmerle JF. IGF-I elicits growth of human intestinal smooth muscle cells by activation of PI3K, PDK-1, and p70S6 kinase. Am J Physiol Gastrointest Liver Physiol 2003; 284:G411-22. [PMID: 12444011 DOI: 10.1152/ajpgi.00310.2002] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endogenous IGF-I regulates growth of human intestinal smooth muscle cells by jointly activating phosphatidylinositol 3-kinase (PI3K) and ERK1/2. The 70-kDa ribosomal S6 kinase (p70S6 kinase) is a key regulator of cell growth activated by several independently regulated kinases. The present study characterized the role of p70S6 kinase in IGF-I-induced growth of human intestinal smooth muscle cells and identified the mechanisms of p70S6 kinase activation. IGF-I-induced growth elicited via either the PI3K or ERK1/2 pathway required activation of p70S6 kinase. IGF-I elicited concentration-dependent activation of PI3K, 3-phosphoinositide-dependent kinase-1 (PDK-1), and p70S6 kinase that was sequential and followed similar time courses. IGF-I caused time-dependent and concentration-dependent phosphorylation of p70S6 kinase on Thr(421)/Ser(424), Thr(389), and Thr(229) that paralleled p70S6 kinase activation. p70S6 kinase(Thr(421)/Ser(424)) phosphorylation was PI3K dependent and PDK-1 independent, whereas p70S6 kinase(Thr(389)) and p70S6 kinase(Thr(229)) phosphorylation and p70S6 kinase activation were PI3K dependent and PDK-1 dependent. IGF-I elicited sequential Akt(Ser(308)), Akt(Ser(473)), and mammalian target of rapamycin(Ser(2448)) phosphorylation; however, transfection of muscle cells with kinase-inactive Akt1(K179M) showed that these events were not required for IGF-I to activate p70S6 kinase and stimulate proliferation of human intestinal muscle cells.
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Affiliation(s)
- John F Kuemmerle
- Departments of Medicine and Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298-0711, USA.
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Mang CF, Truempler S, Erbelding D, Kilbinger H. Modulation by NO of acetylcholine release in the ileum of wild-type and NOS gene knockout mice. Am J Physiol Gastrointest Liver Physiol 2002; 283:G1132-8. [PMID: 12381527 DOI: 10.1152/ajpgi.00192.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nitric oxide (NO) inhibits the release of acetylcholine and cholinergic contractions in the small intestine of several species, but no information is available about the mouse ileum. This study examines the effects of NO on the electrically evoked release of [3H]acetylcholine and smooth muscle contraction in myenteric plexus-longitudinal muscle preparations of wild-type mice and of neuronal NO synthase (nNOS) and endothelial NOS (eNOS) knockout mice. The NOS inhibitor N(G)-nitro-L-arginine (L-NNA) and the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ) concentration dependently increased the evoked [3H]acetylcholine release and cholinergic contractions in preparations from wild-type mice and from eNOS knockout mice. Effects of L-NNA were specifically antagonized by L-arginine. In contrast, L-NNA and ODQ did not modify the release and contractions in preparations from nNOS knockout mice. The NO donor S-nitroso-N-acetyl-DL-penicillamine inhibited the electrically evoked release of [3H]acetylcholine and longitudinal muscle contractions in a quantitatively similar manner in wild-type preparations as well as in nNOS and eNOS knockout preparations. We conclude that endogenous NO released by electrical field stimulation tonically inhibits the release of acetylcholine. Furthermore, data suggest that nNOS and not eNOS is the enzymatic source of NO-mediating inhibition of cholinergic neurotransmission in mouse ileum.
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Affiliation(s)
- Christian F Mang
- Department of Pharmacology, University of Mainz, D-55101 Mainz, Germany
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45
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Chen YM, Qian ZM, Zhang J, Chang YZ, Duan XL. Distribution of constitutive nitric oxide synthase in the jejunum of adult rat. World J Gastroenterol 2002; 8:537-9. [PMID: 12046087 PMCID: PMC4656438 DOI: 10.3748/wjg.v8.i3.537] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the distribution of the constitutive nitric oxide synthase (NOS) in the jejunum of adult rat.
METHODS: The distribution of endothelial NOS (eNOS) was detected by immunohistochemistry. Immunofluorescence histochemical dual staining technique were used for studying the distribution of neuronal NOS (nNOS) and eNOS. The dual stained slides were observed under a confocal laser scanning microscope.
RESULTS: Positive neuronal NOS (nNOS) and endothelial NOS (eNOS) cells were found to be distributed in lamina propria of villi, and the epithelial cell was not stained. eNOS was mainly located in submucosal vascular endothelia, while nNOS was mainly situated in myenteric plexus. Some cells in the villi had both nNOS and eNOS. More than 80% of the cells were positive for both nNOS and eNOS, the rest cells were positive either for nNOS or for eNOS.
CONCLUSION: The two constitutive nitric oxide synthases are distributed differently in the jejunum of rat. nNOS distributed in myenteric plexus is a neurotransmitter in the non-adrenergic non-cholinergic (NANC) inhibitory nerves. eNOS distributed in endothelial and smooth muscle cells of blood vessels plays vasodilator role. eNOS and nNOS are coexpressed in some cells of lamina propria of villi. NO generated by those NOS is very important in the physiological and pathological process of small intestine.
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Affiliation(s)
- Yan-Min Chen
- Life Science College, Hebei Normal University, Shijiazhuang 050016, Hebei Province, China
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46
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Wang X, Zhong YX, Zhang ZY, Lu J, Lan M, Miao JY, Guo XG, Shi YQ, Zhao YQ, Ding J, Wu KC, Pan BR, Fan DM. Effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats. World J Gastroenterol 2002; 8:328-32. [PMID: 11925618 PMCID: PMC4658377 DOI: 10.3748/wjg.v8.i2.328] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of L-NAME on nitric oxide and gastrointestinal motility alterations in cirrhotic rats.
METHODS: Rats with cirrhosis induced by carbon tetrachloride were randomly divided into two groups, one (n = 13) receiving
0.5 mg·kg-1 per day of N G-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, for 10 d, whereas the other group (n = 13) and control (n = 10) rats were administrated the same volume of 9 g•L⁻¹ saline. Half gastric emptying time and 2 h residual rate were measured by SPECT, using 99mTc-DTPA-labeled barium sulfate as test meal. Gastrointestinal transition time was recorded simultaneously. Serum concentration of nitric oxide (NO) was determined by the kinetic cadmium reduction and colorimetric methods. Immunohistochemical SABC method was used to observe the expression and distribution of three types of nitric oxide synthase (NOS) isoforms in the rat gastrointestinal tract. Western blot was used to detect expression of gastrointestinal NOS isoforms.
RESULTS: Half gastric emptying time and trans-gastrointestinal time were significantly prolonged (124.0 ± 26.4 min; 33.7 ± 8.9 min; 72.1 ± 15.3 min; P < 0.01), (12.4 ± 0.5 h; 9.5 ± 0.3 h; 8.2 ± 0.8 h; P < 0.01), 2 h residual rate was raised in cirrhotic rats than in controls and cirrhotic rats treated with L-NAME (54.9% ± 7.6%, 13.7% ± 3.2%, 34.9% ± 10.3%, P < 0.01). Serum concentration of NO was significantly increased in cirrhotic rats than in the other groups (8.20 ± 2.48) μmol•L⁻¹, (5.94 ± 1.07) μmol•L⁻¹, and control (5.66 ± 1.60) μmol•L⁻¹, P < 0.01. NOS staining intensities which were mainly located in the gastrointestinal tissues were markedly lower in cirrhotic rats than in the controls and cirrhotic rats after treated with L-NAME.
CONCLUSION: Gastrointestinal motility was remarkably inhibited in cirrhotic rats, which could be alleviated by L-NAME.Nitric oxide may play an important role in the inhibition of gastrointestinal motility in cirrhotic rats.
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Affiliation(s)
- Xin Wang
- Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710033, Shaanxi Province, China
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47
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Affiliation(s)
- Juan V Esplugues
- Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Spain.
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48
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Guibert C, Flemming R, Beech DJ. Prevention of a hypoxic Ca(2+)(i) response by SERCA inhibitors in cerebral arterioles. Br J Pharmacol 2002; 135:927-34. [PMID: 11861320 PMCID: PMC1573211 DOI: 10.1038/sj.bjp.0704547] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The aim of the study was to investigate the mechanism of a novel effect of hypoxia on intracellular Ca(2+) signalling in rabbit cerebral arteriolar smooth muscle cells, an effect that was resistant to the L-type Ca(2+) channel antagonist methoxyverapamil (D600). 2.[Ca(2+)](i) of smooth muscle cells in intact arteriolar fragments was measured using the Ca(2+)-indicator dye fura-PE3. Hypoxia (PO(2) 10 - 20 mmHg) lowered basal [Ca(2+)](i) but did not inhibit Ca(2+) entry pathways measured by Mn(2+)-quenching of fura-PE3. 3. The effect of hypoxia was completely prevented by thapsigargin or cyclopiazonic acid, selective inhibitors of sarcoplasmic reticulum Ca(2+) ATPase (SERCA). Since these inhibitors do not block Ca(2+) extrusion or uptake via the plasma membrane, the data indicate that the effect of hypoxia depends on a functional sarcoplasmic reticulum. 4. Because actions of nitric oxide (NO) on vascular smooth muscle are also prevented by SERCA inhibitors it was explored whether the effect of hypoxia occurred via modulation of endogenous NO release. Residual NOS-I and NOS-III were detected by immunostaining, and there were NO-dependent effects of NOS inhibitors on Ca(2+)(i)-signalling. Nevertheless, inhibition of endogenous NO production did not prevent the effect of hypoxia on [Ca(2+)](i). 5. The experiments reveal a novel nitric oxide-independent effect of hypoxia that is prevented by SERCA inhibitors.
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Affiliation(s)
- C Guibert
- School of Biomedical Sciences, Worsley Building, University of Leeds, Leeds LS2 9JT
| | - R Flemming
- School of Biomedical Sciences, Worsley Building, University of Leeds, Leeds LS2 9JT
| | - D J Beech
- School of Biomedical Sciences, Worsley Building, University of Leeds, Leeds LS2 9JT
- Author for correspondence:
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Dick JMC, Van Molle W, Brouckaert P, Lefebvre RA. Relaxation by vasoactive intestinal polypeptide in the gastric fundus of nitric oxide synthase-deficient mice. J Physiol 2002; 538:133-43. [PMID: 11773322 PMCID: PMC2290014 DOI: 10.1113/jphysiol.2001.012906] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In many gastrointestinal tissues nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) both play a role as inhibitory non-adrenergic non-cholinergic neurotransmitters. As the mode of interaction between NO and VIP remains controversial, the aim of this study was to investigate the interplay between NO and VIP in the mouse gastric fundus and to evaluate the nitric oxide synthase (NOS) isoform involved in VIP-induced relaxation by using inducible NOS (iNOS), endothelial NOS (eNOS) and neuronal NOS (nNOS) knockout mice. The influence of NOS inhibitors on the relaxant effect of VIP was determined in isolated smooth muscle cells and smooth muscle strips of wild-type and knockout mice. In isolated smooth muscle cells from wild-type, eNOS knockout and nNOS knockout mice, the relaxation induced by VIP (10(-9) M) was inhibited by approximately 70-95 % by both the non-selective NOS inhibitor N(G)-nitro-L-arginine (L-NA; 10(-4) M) and the selective inducible NOS inhibitor N-(3-(aminomethyl)-benzyl)acetamidine (1400W; 10(-6) M). In cells isolated from iNOS knockout mice, VIP still induced full relaxation but it was not influenced by L-NA or 1400W. In smooth muscle strips from wild-type and knockout mice, the concentration-dependent relaxation by VIP (10(-9) to 3 x 10(-7) M) was not influenced by L-NA or 1400W. These results suggest that the experimental method determines the influence of NOS inhibitors on the relaxant effect of VIP. iNOS, probably induced by the isolation procedure, might be involved in the relaxant effect of VIP in isolated smooth muscle cells but not in classic smooth muscle strips.
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Affiliation(s)
- Joëlle M C Dick
- Heymans Institute of Pharmacology, Faculty of Medicine and Health Sciences, Ghent University, De Pintelaan 185, B-9000 Ghent, Belgium
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50
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Peng X, Feng JB, Yan H, Zhao Y, Wang SL. Distribution of nitric oxide synthase in stomach myenteric plexus of rats. World J Gastroenterol 2001; 7:852-4. [PMID: 11854915 PMCID: PMC4695608 DOI: 10.3748/wjg.v7.i6.852] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the distribution of nitric oxide synthase (NOS) in rat stomach myenteric plexus.
METHODS: The distribution of NOS in gastric wall was studied in quantity and location by the NADPH-diaphorase (NDP) histochemical staining method and whole mount preparation technique.
RESULTS: NOS was distributed in whole stomach wall, most of them were located in myenteric plexus, and distributed in submucosal plexus. The shape of NOS positive neurons was basically similar, most of them being round and oval in shape. But their density, size and staining intensity varied greatly in the different parts of stomach. The density was 62 ± 38 cells/mm2 (antrum), 43 ± 32 cells/mm2 (body), and 32 ± 28 cells/mm2 (fundus), respectively. The size and staining intensity of NOS positive neurons in the fundus were basically the same, the neurons being large and dark stained, while they were obviously different in antrum. In the body of the stomach, the NOS positive neurons were in an intermediate state from fundus to antrum. There were some beadlike structures which were strung together by NOS positive varicosities in nerve fibers, some were closely adherent to the outer walls of blood vessels.
CONCLUSION: Nitric oxide might be involved in the modulation of motility, secretion and blood circulation of the stomach, and the significant difference of NOS positive neurons in different parts of stomach myenteric plexus may be related to the physiologic function of stomach.
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Affiliation(s)
- X Peng
- Institute of Burn Research, Southwestern Hospital, Third Military Medical University, Chongqing 400038, China.
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