1
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Lin YM, Hegde S, Cong Y, Shi XZ. Mechanisms of lymphoid depletion in bowel obstruction. Front Physiol 2022; 13:1005088. [PMID: 36213246 PMCID: PMC9533077 DOI: 10.3389/fphys.2022.1005088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/07/2022] [Indexed: 12/15/2022] Open
Abstract
Background and aims: Bowel obstruction (BO) causes not only gastrointestinal dysfunctions but also systemic responses such as sepsis, infections, and immune impairments. The mechanisms involved are not well understood. In this study, we tested the hypothesis that BO leads to lymphoid depletion in primary and peripheral lymphoid organs, which may contribute to systemic responses. We also sought to uncover mechanisms of lymphoid depletion in BO. Methods: Partial colon obstruction was induced with a band in the distal colon of Sprague-Dawley rats, and wild-type and osteopontin knockout (OPN-/-) mice. Obstruction was maintained for 7 days in rats and 4 days in mice. Thymus, bone marrow, spleen, and mesenteric lymph node (MLN) were taken for flow cytometry analysis. Results: The weight of thymus, spleen, and MLN was significantly decreased in BO rats, compared to sham. B and T lymphopoiesis in the bone marrow and thymus was suppressed, and numbers of lymphocytes, CD4+, and CD8+ T cells in the spleen and MLN were all decreased in BO. Depletion of gut microbiota blocked BO-associated lymphopenia in the MLN. Corticosterone antagonism partially attenuated BO-associated reduction of lymphocytes in the thymus and bone marrow. Plasma OPN levels and OPN expression in the distended colon were increased in BO. Deletion of the OPN gene did not affect splenic lymphopenia, but attenuated suppression of lymphopoiesis in the bone marrow and thymus in BO. Conclusions: BO suppresses lymphocyte generation and maintenance in lymphoid organs. Mechanical distention-induced OPN, corticosterone, and gut microbiota are involved in the immune phenotype in BO.
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Affiliation(s)
- You-Min Lin
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States,Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Shrilakshmi Hegde
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Yingzi Cong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Xuan-Zheng Shi
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States,*Correspondence: Xuan-Zheng Shi,
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2
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Geesala R, Lin YM, Zhang K, Shi XZ. Targeting Mechano-Transcription Process as Therapeutic Intervention in Gastrointestinal Disorders. Front Pharmacol 2021; 12:809350. [PMID: 34992543 PMCID: PMC8724579 DOI: 10.3389/fphar.2021.809350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/06/2021] [Indexed: 12/16/2022] Open
Abstract
Mechano-transcription is a process whereby mechanical stress alters gene expression. The gastrointestinal (GI) tract is composed of a series of hollow organs, often encountered by transient or persistent mechanical stress. Recent studies have revealed that persistent mechanical stress is present in obstructive, functional, and inflammatory disorders and alters gene transcription in these conditions. Mechano-transcription of inflammatory molecules, pain mediators, pro-fibrotic and growth factors has been shown to play a key role in the development of motility dysfunction, visceral hypersensitivity, inflammation, and fibrosis in the gut. In particular, mechanical stress-induced cyclooxygenase-2 (COX-2) and certain pro-inflammatory mediators in gut smooth muscle cells are responsible for motility dysfunction and inflammatory process. Mechano-transcription of pain mediators such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) may lead to visceral hypersensitivity. Emerging evidence suggests that mechanical stress in the gut also leads to up-regulation of certain proliferative and pro-fibrotic mediators such as connective tissue growth factor (CTGF) and osteopontin (OPN), which may contribute to fibrostenotic Crohn's disease. In this review, we will discuss the pathophysiological significance of mechanical stress-induced expression of pro-inflammatory molecules, pain mediators, pro-fibrotic and growth factors in obstructive, inflammatory, and functional bowel disorders. We will also evaluate potential therapeutic targets of mechano-transcription process for the management of these disorders.
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3
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Hegde S, Lin YM, Fu Y, Savidge T, Shi XZ. Precision Lactobacillus reuteri therapy attenuates luminal distension-associated visceral hypersensitivity by inducing peripheral opioid receptors in the colon. Pain 2020; 161:2737-2749. [PMID: 32569084 PMCID: PMC7669621 DOI: 10.1097/j.pain.0000000000001967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Luminal distension and abdominal pain are major clinical hallmarks of obstructive bowel disorders and functional bowel disorders linked to gut dysbiosis. Our recent studies found that chronic lumen distension increased visceral sensitivity and decreased abundance of gut commensal Lactobacillus reuteri in a rodent model of partial colon obstruction (OB). To establish causation, we performed precision microbial therapy to assess whether recolonization of L. reuteri prevents visceral hypersensitivity in lumen distension, and if so, to identify the gut-microbiota mechanism. Lumen distension was induced in Sprague-Dawley rats by implanting an OB band in the distal colon for up to 7 days. L. reuteri strains or vehicle were gavage ingested 1 × 10 colony-forming units/g daily starting 2 days before OB. L. reuteri rat strains that were able to recolonize obstructed colon significantly improved food intake and body weight in OB rats, and attenuated referred visceral hyperalgesia measured by the withdrawal response to von Frey filament applications to the abdomen. Mechanistically, L. reuteri treatment attenuated hyperexcitability of the dorsal root ganglia neurons projecting to the distended colon by promoting opioid receptor function in affected tissues. The expression of µ, δ, and κ opioid receptors was significantly downregulated in colonic muscularis externae and sensory neurons in OB rats. However, L. reuteri treatment prevented the loss of opioid receptors. Furthermore, administration of peripheral opioid receptor antagonist naloxone methiodide abolished the analgesic effect of L. reuteri in OB. In conclusion, precision L. reuteri therapy prevents lumen distension-associated visceral hypersensitivity by local bacterial induction of opioid receptors.
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Affiliation(s)
- Shrilakshmi Hegde
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - You-Min Lin
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Yu Fu
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Tor Savidge
- Dept. of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Xuan-Zheng Shi
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
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4
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Wang Q, Zang J, Huang X, Lu H, Xu W, Chen J. Colonic Dysmotility in Murine Partial Colonic Obstruction Due to Functional Changes in Interstitial Cells. J Neurogastroenterol Motil 2019; 25:589-601. [PMID: 31587550 PMCID: PMC6786438 DOI: 10.5056/jnm19136] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/07/2019] [Accepted: 08/27/2019] [Indexed: 12/11/2022] Open
Abstract
Background/Aims Interstitial cells play important roles in gastrointestinal (GI) neuro-smooth muscle transmission. The underlying mechanisms of colonic dysmotility have not been well illustrated. We established a partial colon obstruction (PCO) mouse model to investigate the changes of interstitial cells and the correlation with colonic motility. Methods Western blot technique was employed to observe the protein expressions of Kit, platelet-derived growth factor receptor-α (Pdgfra), Ca2+-activated Cl− (Ano1) channels, and small conductance Ca2+- activated K+ (SK) channels. Colonic migrating motor complexes (CMMCs) and isometric force measurements were employed in control mice and PCO mice. Results PCO mice showed distended abdomen and feces excretion was significantly reduced. Anatomically, the colon above the obstructive silicone ring was obviously dilated. Kit and Ano1 proteins in the colonic smooth muscle layer of the PCO colons were significantly decreased, while the expression of Pdgfra and SK3 proteins were significantly increased. The effects of a nitric oxide synthase inhibitor (L-NAME) and an Ano1 channel inhibitor (NPPB) on CMMC and colonic spontaneous contractions were decreased in the proximal and distal colons of PCO mice. The SK agonist, CyPPA and antagonist, apamin in PCO mice showed more effect to the CMMCs and colonic smooth muscle contractions. Conclusions Colonic transit disorder may be due to the downregulation of the Kit and Ano1 channels and the upregulation of SK3 channels in platelet-derived growth factor receptor-α positive (PDGFRα+) cells. The imbalance between interstitial cells of Cajal-Ano1 and PDGFRα-SK3 distribution might be a potential reason for the colonic dysmotility.
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Affiliation(s)
- Qianqian Wang
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Pediatric Surgery, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, China
| | - Jingyu Zang
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Pediatric Surgery, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, China
| | - Xu Huang
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hongli Lu
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenxie Xu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jie Chen
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Pediatric Surgery, Jiaxing Maternity and Child Health Care Hospital, Jiaxing, China
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5
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Pingyu Z, Binglei J, Qilong J, Tao W, Wei T. Cyclic Stretch Promotes Proliferation and Contraction of Human Bladder Smooth Muscle Cells by Cajal-Mediated c-kit Expression in Interstitial Cells. Med Sci Monit 2019; 25:4784-4792. [PMID: 31249285 PMCID: PMC6612242 DOI: 10.12659/msm.917549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background The present study was performed to assess the effect of mechanical stretch on the proliferation and contractile function of hBSMCs. Material/Methods hBSMCs and ICCs were seeded at 8×104 cells/well in 6-well silicone elastomer-bottomed culture plates coated with type I collagen, and grown to 80% confluence in DMEM/10% FBS and a 5% CO2 humidified atmosphere at 37°C. Cells of hBSMCs and hBSMCs/ICCs of co-culture were then subjected to continuous cycles of stretch-relaxation using a computer-driven, stretch-inducing device. The treated concentration of imatinib was 10 μM. Mechanisms underlying observed hBSMCs contraction were examined using Western blotting and RT-PCR. The 0.1 μM carbachol was separately added to the experimental groups, and 300 s was recorded by laser scanning confocal microscope. Results We found that mechanical stretch increased contraction and proliferation of hBSMCs. Calcium ion activity increased significantly after mechanical stretch. The number of hBSMCs was significantly increased after the combination mechanical stretch with ICCs treatment. After combination mechanical stretch with hBSMCs/ICCs treatment, the mRNA and protein level of M2, M3, and c-kit were significantly increased. After combination of mechanical stretch with no imatinib treatment, the proliferation of hBSMCs was higher than others, and the mRNA and protein level of M2 and M3 were significantly increased. Conclusions We revealed that ICCs could promote hBSMC proliferation and contraction, and cyclic stretch could promote acetylcholine receptor M2 and M3 caused by c-kit in the ICCs, which promoted the contraction of hBSMCs.
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Affiliation(s)
- Zhu Pingyu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland).,Department of Urology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Jiang Binglei
- Department of Ultrasound, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Jiang Qilong
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland)
| | - Wu Tao
- Department of Urology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Tang Wei
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland)
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6
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Shi XZ, Lin YM, Hegde S. Novel Insights Into the Mechanisms of Abdominal Pain in Obstructive Bowel Disorders. Front Integr Neurosci 2018; 12:23. [PMID: 29937720 PMCID: PMC6002527 DOI: 10.3389/fnint.2018.00023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/22/2018] [Indexed: 12/27/2022] Open
Abstract
Obstructive bowel disorders (OBD) are characterized by lumen distention due to mechanical or functional obstruction in the gut. Abdominal pain is one of the main symptoms in OBD. In this article, we aim to critically review the potential mechanisms for acute and chronic pain in bowel obstruction (BO). While clustered contractions and associated increase of intraluminal pressure may account for colicky pain in simple obstruction, ischemia may be involved in acute pain in severe conditions such as closed loop obstruction. Recent preclinical studies discovered that visceral sensitivity is increased in BO, and visceral hypersensitivity may underlie the mechanisms of chronic abdominal pain in BO. Mounting evidence suggests that lumen distension, as a circumferential mechanical stretch, alters gene expression (mechano-transcription) in the distended bowel, and mechano-transcription of nociceptive and inflammatory mediators plays a critical role in the development of visceral hypersensitivity in BO. Mechano-transcription of nerve growth factor (NGF) in gut smooth muscle cells is found to increase voltage-gated Na+ channel (Nav) activity of the primary sensory neurons by up-regulating expression of TTX-resistant Nav1.8, whereas mechanical stretch-induced brain-derived neurotrophic factor (BDNF) reduces Kv currents especially A-type (IA) currents by down-regulating expression of specific IA subtypes such as Kv1.4. The NGF and BDNF mediated changes in gene expression and channel functions in the primary sensory neurons may constitute the main mechanisms of visceral hypersensitivity in OBD. In addition, mechanical stretch-induced COX-2 and other inflammatory mediators in the gut may also contribute to abdominal pain by activating and sensitizing nociceptors.
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Affiliation(s)
- Xuan-Zheng Shi
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - You-Min Lin
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Shrilakshmi Hegde
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
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7
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The Turning Point for Morphomechanical Remodeling During Complete Intestinal Obstruction in Rats Occurs After 12–24 h. Ann Biomed Eng 2018; 46:705-716. [DOI: 10.1007/s10439-018-1992-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 02/05/2018] [Indexed: 12/31/2022]
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8
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Shi XZ. Mechanical Regulation of Gene Expression in Gut Smooth Muscle Cells. Front Physiol 2017; 8:1000. [PMID: 29259559 PMCID: PMC5723328 DOI: 10.3389/fphys.2017.01000] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/20/2017] [Indexed: 12/15/2022] Open
Abstract
Intraluminal contents and their movement along the gastrointestinal tract create shear stress and mechanical stretch on the gut wall. While the shear stress is important in the initiation of immediate physiological responses, the circumferential mechanical stretch, such as that in obstructive bowel disorders, exerts long-lasting impacts on bowel functions by mainly affecting the deeper muscularis externae. Recent studies demonstrate that mechanical stretch alters gene transcription in gut smooth muscle cells (SMC), and the stretch-altered gene expression (mechano-transcription) may play a critical role in pathogenesis of motility dysfunction and abdominal pain in obstruction. Specifically, stretch-induced cyclo-oxygenase-2 and other pro-inflammatory mediators in gut SMC account for impairments of muscle contractility. Mechano-transcription of pain mediators such as nerve growth factor may contribute to visceral hypersensitivity, by sensitizing primary sensory neurons. This review aims to highlight the novel findings of mechano-transcription in the gut, and to discuss the signaling mechanisms and pathophysiological significance of mechano-transcription.
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Affiliation(s)
- Xuan-Zheng Shi
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, United States
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9
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Lin YM, Fu Y, Winston J, Radhakrishnan R, Sarna SK, Huang LYM, Shi XZ. Pathogenesis of abdominal pain in bowel obstruction: role of mechanical stress-induced upregulation of nerve growth factor in gut smooth muscle cells. Pain 2017; 158:583-592. [PMID: 28079757 PMCID: PMC5354958 DOI: 10.1097/j.pain.0000000000000797] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abdominal pain is one of the major symptoms in bowel obstruction (BO); its cellular mechanisms remain incompletely understood. We tested the hypothesis that mechanical stress in obstruction upregulates expression of nociception mediator nerve growth factor (NGF) in gut smooth muscle cells (SMCs), and NGF sensitizes primary sensory nerve to contribute to pain in BO. Partial colon obstruction was induced with a silicon band implanted in the distal bowel of Sprague-Dawley rats. Colon-projecting sensory neurons in the dorsal root ganglia (T13 to L2) were identified for patch-clamp and gene expression studies. Referred visceral sensitivity was assessed by measuring withdrawal response to stimulation by von Frey filaments in the lower abdomen. Membrane excitability of colon-projecting dorsal root ganglia neurons was significantly enhanced, and the withdrawal response to von Frey filament stimulation markedly increased in BO rats. The expression of NGF mRNA and protein was increased in a time-dependent manner (day 1-day 7) in colonic SMC but not in mucosa/submucosa of the obstructed colon. Mechanical stretch in vitro caused robust NGF mRNA and protein expression in colonic SMC. Treatment with anti-NGF antibody attenuated colon neuron hyperexcitability and referred hypersensitivity in BO rats. Obstruction led to significant increases of tetrodotoxin-resistant Na currents and mRNA expression of Nav1.8 but not Nav1.6 and Nav1.7 in colon neurons; these changes were abolished by anti-NGF treatment. In conclusion, mechanical stress-induced upregulation of NGF in colon SMC underlies the visceral hypersensitivity in BO through increased gene expression and activity of tetrodotoxin-resistant Na channels in sensory neurons.
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Affiliation(s)
- You-Min Lin
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Yu Fu
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - John Winston
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Ravi Radhakrishnan
- Dept. of Surgery, University of Texas Medical Branch, Galveston, TX, USA
| | - Sushil K. Sarna
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Li-Yen M. Huang
- Dept. of Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Xuan-Zheng Shi
- Dept. of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
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10
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Lin YM, Fu Y, Wu CC, Xu GY, Huang LY, Shi XZ. Colon distention induces persistent visceral hypersensitivity by mechanotranscription of pain mediators in colonic smooth muscle cells. Am J Physiol Gastrointest Liver Physiol 2015; 308:G434-41. [PMID: 25540231 PMCID: PMC4346753 DOI: 10.1152/ajpgi.00328.2014] [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] [Indexed: 02/08/2023]
Abstract
Abdominal pain and distention are major complaints in irritable bowel syndrome. Abdominal distention is mainly attributed to intraluminal retention of gas or solid contents, which may cause mechanical stress to the gut wall. Visceral hypersensitivity (VHS) may account for abdominal pain. We sought to determine whether tonic colon distention causes persistent VHS and if so whether mechanical stress-induced expression (mechanotranscription) of pain mediators in colonic smooth muscle cells (SMCs) plays a role in VHS. Human colonic SMCs were isolated and stretched in vitro to investigate whether mechanical stress upregulates expression of the pain mediator cyclooxygenase-2 (COX-2). Rat colon was distended with a 5-cm-long balloon, and gene expression of COX-2, visceromotor response (VMR), and sensory neuron excitability were determined. Static stretch of colonic SMCs induced marked expression of COX-2 mRNA and protein in a force- and time-dependent manner. Subnoxious tonic distention of the distal colon at ∼30-40 mmHg for 20 or 40 min induced COX-2 expression and PGE2 production in colonic smooth muscle, but not in the mucosa layer. Lumen distention also increased VMR in a force- and time-dependent manner. The increase of VMR persisted for at least 3 days. Patch-clamp experiments showed that the excitability of colon projecting sensory neurons in the dorsal root ganglia was markedly augmented, 24 h after lumen distention. Administration of COX-2 inhibitor NS-398 partially but significantly attenuated distention-induced VHS. In conclusion, tonic lumen distention upregulates expression of COX-2 in colonic SMC, and COX-2 contributes to persistent VHS.
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Affiliation(s)
- You-Min Lin
- 1Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; and
| | - Yu Fu
- 1Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; and
| | - Chester C. Wu
- 1Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; and
| | - Guang-Yin Xu
- 1Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; and
| | - Li-Yen Huang
- 2Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas
| | - Xuan-Zheng Shi
- Division of Gastroenterology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; and
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11
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Lin YM, Li F, Shi XZ. Mechanical stress is a pro-inflammatory stimulus in the gut: in vitro, in vivo and ex vivo evidence. PLoS One 2014; 9:e106242. [PMID: 25180799 PMCID: PMC4152012 DOI: 10.1371/journal.pone.0106242] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/28/2014] [Indexed: 12/14/2022] Open
Abstract
Aims Inflammatory infiltrates and pro-inflammatory mediators are found increased in obstructive and functional bowel disorders, in which lumen distention is present. However, what caused the low level inflammation is not well known. We tested the hypothesis that lumen distention- associated mechanical stress may induce expression of specific inflammatory mediators in gut smooth muscle. Methods Static mechanical stretch (18% elongation) was applied in vitro in primary culture of rat colonic circular smooth muscle cells (RCCSMCs) with a Flexercell FX-4000 Tension Plus System. Mechanical distention in vivo was induced in rats with an obstruction band placed in the distal colon. Results In the primary culture of RCCSMCs, we found that static stretch significantly induced mRNA expression of iNOS, IL-6, and MCP-1 in 3 hours by 6.0(±1.4), 2.5(±0.5), and 2.2(±0.5) fold (n = 6∼8, p<0.05), respectively. However, gene expression of TNF-α, IL-1β, and IL-8 was not significantly affected by mechanical stretch. In the in vivo model of colon obstruction, we found that gene expression of iNOS, IL-6, and MCP-1 is also significantly increased in a time-dependent manner in the mechanically distended proximal segment, but not in the sham controls or distal segments. The conditioned medium from the muscle strips of the stretched proximal segment, but not the distal segment or control, significantly induced translocation and phosphorylation of NF-κB p65. This treatment further increased mRNA expression of inflammatory mediators in the naïve cells. However, treatment of the conditioned medium from the proximal segment with neutralizing antibody against rat IL-6 significantly attenuated the activation of NF-κB and gene expression of inflammatory mediators. Conclusions Our studies demonstrate that mechanical stress induces gene expression of inflammatory mediators i.e. iNOS, IL-6, and MCP-1 in colonic SMC. Further ex vivo study showed that mechanical stress functions as a pro-inflammatory stimulus in the gut.
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MESH Headings
- Animals
- Antibodies, Neutralizing/pharmacology
- Cells, Cultured
- Chemokines/genetics
- Chemokines/metabolism
- Colon/pathology
- Culture Media, Conditioned/pharmacology
- Gastrointestinal Tract/drug effects
- Gastrointestinal Tract/pathology
- Inflammation/pathology
- Inflammation Mediators/metabolism
- Intestinal Obstruction/pathology
- Male
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- NF-kappa B/metabolism
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type II/genetics
- Nitric Oxide Synthase Type II/metabolism
- Phosphorylation/drug effects
- Protein Transport/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Stress, Mechanical
- Up-Regulation/drug effects
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Affiliation(s)
- You-Min Lin
- Division of Gastroenterology, Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Feng Li
- Division of Gastroenterology, Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Xuan-Zheng Shi
- Division of Gastroenterology, Department of Internal Medicine, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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12
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Altomare A, Gizzi A, Guarino MPL, Loppini A, Cocca S, Dipaola M, Alloni R, Cicala M, Filippi S. Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility. Am J Physiol Gastrointest Liver Physiol 2014; 307:G77-88. [PMID: 24833706 DOI: 10.1152/ajpgi.00385.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.
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Affiliation(s)
- A Altomare
- Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy
| | - A Gizzi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and
| | - M P L Guarino
- Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy
| | - A Loppini
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and
| | - S Cocca
- Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy
| | - M Dipaola
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and Politecnico di Milano, Milano, Italy; and
| | - R Alloni
- Surgery Unit, University Campus Bio-Medico of Rome, Rome, Italy
| | - M Cicala
- Gastroenterology Unit, University Campus Bio-Medico of Rome, Rome, Italy;
| | - S Filippi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Rome, Italy; and International Center for Relativistic Astrophysics, Pescara, Italy
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