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Small molecule inhibitors and stimulators of inducible nitric oxide synthase in cancer cells from natural origin (phytochemicals, marine compounds, antibiotics). Biochem Pharmacol 2020; 176:113792. [PMID: 31926145 DOI: 10.1016/j.bcp.2020.113792] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 01/03/2020] [Indexed: 02/06/2023]
Abstract
Nitric oxide synthases (NOS) are a family of isoforms, which generate nitric oxide (NO). NO is one of the smallest molecules in nature and acts mainly as a potent vasodilator. It participates in various biological processes ranging from physiological to pathological conditions. Inducible NOS (iNOS, NOS2) is a calcium-independent and inducible isoform. Despite high iNOS expression in many tumors, the role of iNOS is still unclear and complex with both enhancing and prohibiting actions in tumorigenesis. Nature presents a broad variety of natural stimulators and inhibitors, which may either promote or inhibit iNOS response. In the present review, we give an overview of iNOS-modulating agents with a special focus on both natural and synthetic molecules and their effects in related biological processes. The role of iNOS in physiological and pathological conditions is also discussed.
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Mu K, Yu S, Kitts DD. The Role of Nitric Oxide in Regulating Intestinal Redox Status and Intestinal Epithelial Cell Functionality. Int J Mol Sci 2019; 20:E1755. [PMID: 30970667 PMCID: PMC6479862 DOI: 10.3390/ijms20071755] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 03/29/2019] [Accepted: 04/03/2019] [Indexed: 12/11/2022] Open
Abstract
Important functions of intestinal epithelial cells (IECs) include enabling nutrient absorption to occur passively and acting as a defense barrier against potential xenobiotic components and pathogens. A compromise to IEC function can result in the translocation of bacteria, toxins, and allergens that lead to the onset of disease. Thus, the maintenance and optimal function of IECs are critically important to ensure health. Endogenous biosynthesis of nitric oxide (NO) regulates IEC functionality both directly, through free radical activity, and indirectly through cell signaling mechanisms that impact tight junction protein expression. In this paper, we review the current knowledge on factors that regulate inducible nitric oxide synthase (iNOS) and the subsequent roles that NO has on maintaining IECs' intestinal epithelial barrier structure, functions, and associated mechanisms of action. We also summarize important findings on the effects of bioactive dietary food components that interact with NO production and affect downstream intestinal epithelium integrity.
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Affiliation(s)
- Kaiwen Mu
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Shengwu Yu
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - David D Kitts
- Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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Yu LCH. Microbiota dysbiosis and barrier dysfunction in inflammatory bowel disease and colorectal cancers: exploring a common ground hypothesis. J Biomed Sci 2018; 25:79. [PMID: 30413188 PMCID: PMC6234774 DOI: 10.1186/s12929-018-0483-8] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a multifactorial disease which arises as a result of the interaction of genetic, environmental, barrier and microbial factors leading to chronic inflammation in the intestine. Patients with IBD had a higher risk of developing colorectal carcinoma (CRC), of which the subset was classified as colitis-associated cancers. Genetic polymorphism of innate immune receptors had long been considered a major risk factor for IBD, and the mutations were also recently observed in CRC. Altered microbial composition (termed microbiota dybiosis) and dysfunctional gut barrier manifested by epithelial hyperpermeability and high amount of mucosa-associated bacteria were observed in IBD and CRC patients. The findings suggested that aberrant immune responses to penetrating commensal microbes may play key roles in fueling disease progression. Accumulative evidence demonstrated that mucosa-associated bacteria harbored colitogenic and protumoral properties in experimental models, supporting an active role of bacteria as pathobionts (commensal-derived opportunistic pathogens). Nevertheless, the host factors involved in bacterial dysbiosis and conversion mechanisms from lumen-dwelling commensals to mucosal pathobionts remain unclear. Based on the observation of gut leakiness in patients and the evidence of epithelial hyperpermeability prior to the onset of mucosal histopathology in colitic animals, it was postulated that the epithelial barrier dysfunction associated with mucosal enrichment of specific bacterial strains may predispose the shift to disease-associated microbiota. The speculation of leaky gut as an initiating factor for microbiota dysbiosis that eventually led to pathological consequences was proposed as the "common ground hypothesis", which will be highlighted in this review. Overall, the understanding of the core interplay between gut microbiota and epithelial barriers at early subclinical phases will shed light to novel therapeutic strategies to manage chronic inflammatory disorders and colitis-associated cancers.
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Affiliation(s)
- Linda Chia-Hui Yu
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Suite 1020, #1 Jen-Ai Rd. Sec. 1, Taipei, 100, Taiwan, Republic of China.
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Pitsikas N. The role of nitric oxide (NO) donors in anxiety. Lights and shadows. Nitric Oxide 2018; 77:6-11. [DOI: 10.1016/j.niox.2018.04.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/01/2018] [Accepted: 04/02/2018] [Indexed: 12/28/2022]
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5
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Rahimi N, Hassanipour M, Allahabadi NS, Sabbaghziarani F, Yazdanparast M, Dehpour A. Cirrhosis induced by bile duct ligation alleviates acetic acid intestinal damages in rats: Involvements of nitrergic and opioidergic systems. Pharmacol Rep 2018; 70:426-433. [DOI: 10.1016/j.pharep.2017.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/24/2017] [Accepted: 11/21/2017] [Indexed: 02/07/2023]
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6
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Tuning the inflammatory response to silver nanoparticles via quercetin in Caco-2 (co-)cultures as model of the human intestinal mucosa. Toxicol Lett 2016; 253:36-45. [PMID: 27113704 DOI: 10.1016/j.toxlet.2016.04.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/17/2016] [Accepted: 04/20/2016] [Indexed: 02/06/2023]
Abstract
Interaction of nanoparticles with food matrix components may cause unpredictable health complications. Using an improved Caco-2 cell-based in vitro (co-)culture model the potential of quercetin as one of the major food flavonoids to alter the effect of silver nanoparticles (Ag-NPs) <20 nm in the human intestinal mucosa at real life concentrations was investigated. Ag-NPs (15-90 μg/ml) decreased cell viability and reduced thiol groups, induced oxidative/nitrosative stress and lipid peroxidation and led to activity changes of various antioxidant enzymes after 3h exposure. The contribution of Ag(+) ions within the concentrations released from nanoparticles was shown to be less important, compared to Ag-NPs. While leading to inflammatory response in the intestines, Ag-NPs, paradoxically, also showed a potential anti-infammatory effect manifested in down-regulated IL-8 levels. Quercetin, co-administered with Ag-NPs, led to a reduction of cytotoxicity, oxidative stress, and recovered metabolic activity of Caco-2 cells, suggesting the protective effects of this flavonoid against the harmful effect of Ag-NPs. Quercetin not only alleviated the effect of Ag-NPs on the gastrointestinal cells, but also demonstrated a potential to serve as a tool for reversible modulation of intestinal permeability.
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Abstract
Microscopic colitis (MC) is a common cause of chronic diarrhea. The 2 most frequent forms of MC are collagenous colitis and lymphocytic colitis. Over the past years, the incidence and prevalence of microscopic colitis are rising and this is largely attributed to a greater awareness, and concomitantly an increasing number of diagnoses. Patients with microscopic colitis report watery, nonbloody diarrhea of chronic course, abdominal pain, weight loss, and fatigue that may impair patient's health-related quality of life. The underlying mechanisms involved in the pathogenesis of microscopic colitis remain unspecified but is probably multifactorial. Collagenous colitis and lymphocytic colitis may represent specific mucosal responses to different luminal agents in predisposed individuals, resulting in an uncontrolled immune response. Genetic predisposition, altered modulation of cytokines and miRNAs, and aberrant response to drugs seem to be involved in the development of MC. Despite the progress of knowledge, still many questions remain unsolved regarding the etiology, pathophysiology, and optimal management of MC. This review gives an update on the immunological aspects of collagenous colitis and lymphocytic colitis.
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8
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The role of nitric oxide donors in schizophrenia: Basic studies and clinical applications. Eur J Pharmacol 2015; 766:106-13. [DOI: 10.1016/j.ejphar.2015.09.045] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 01/04/2023]
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Kumawat AK, Strid H, Tysk C, Bohr J, Hörnquist EH. Microscopic colitis patients demonstrate a mixed Th17/Tc17 and Th1/Tc1 mucosal cytokine profile. Mol Immunol 2013; 55:355-64. [PMID: 23566938 DOI: 10.1016/j.molimm.2013.03.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 12/22/2022]
Abstract
BACKGROUND Microscopic colitis (MC) is a chronic inflammatory bowel disorder of unknown aetiology comprising collagenous colitis (CC) and lymphocytic colitis (LC). Data on the local cytokine profile in MC is limited. This study investigated the T helper (Th) cell and cytotoxic T lymphocyte (CTL) mucosal cytokine profile at messenger and protein levels in MC patients. METHODS Mucosal biopsies from CC (n=10), LC (n=5), and CC or LC patients in histopathological remission (CC-HR, n=4), (LC-HR, n=6), ulcerative colitis (UC, n=3) and controls (n=10) were analysed by real-time PCR and Luminex for expression/production of IL-1β, -4, -5, -6, -10, -12, -17, -21, -22, -23, IFN-γ, TNF-α, T-bet and RORC2. RESULTS Mucosal mRNA but not protein levels of IFN-γ and IL-12 were significantly up regulated in CC, LC as well as UC patients compared to controls. Transcription of the Th1 transcription factor T-bet was significantly enhanced in CC but not LC patients. mRNA levels for IL-17A, IL-21, IL-22 and IL-6 were significantly up regulated in CC and LC patients compared to controls, albeit less than in UC patients. Significantly enhanced IL-21 protein levels were noted in both CC and LC patients. IL-6 protein and IL-1β mRNA levels were increased in CC and UC but not LC patients. Increased mucosal mRNA levels of IFN-γ, IL-21 and IL-22 were correlated with higher clinical activity, recorded as the number of bowel movements per day, in MC patients. Although at lower magnitude, IL-23A mRNA was upregulated in CC and LC, whereas TNF-α protein was increased in CC, LC as well as in UC patients. Neither mRNA nor protein levels of IL-4, IL-5 or IL-10 were significantly changed in any of the colitis groups. LC-HR and especially CC-HR patients had normalized mRNA and protein levels of the above cytokines compared to LC and CC patients. No significant differences were found between LC and CC in cytokine expression/production. CONCLUSION LC and CC patients demonstrate a mixed Th17/Tc17 and Th1/Tc1 mucosal cytokine profile.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Case-Control Studies
- Colitis, Collagenous/genetics
- Colitis, Collagenous/immunology
- Colitis, Collagenous/pathology
- Colitis, Lymphocytic/genetics
- Colitis, Lymphocytic/immunology
- Colitis, Lymphocytic/pathology
- Colitis, Microscopic/genetics
- Colitis, Microscopic/immunology
- Colitis, Microscopic/pathology
- Cytokines/biosynthesis
- Cytokines/genetics
- Female
- Humans
- Immunity, Mucosal/genetics
- Male
- Middle Aged
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/pathology
- Th1 Cells/immunology
- Th1 Cells/pathology
- Th17 Cells/immunology
- Th17 Cells/pathology
- Young Adult
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Kumawat AK, Strid H, Elgbratt K, Tysk C, Bohr J, Hultgren Hörnquist E. Microscopic colitis patients have increased proportions of Ki67(+) proliferating and CD45RO(+) active/memory CD8(+) and CD4(+)8(+) mucosal T cells. J Crohns Colitis 2013; 7:694-705. [PMID: 22995775 DOI: 10.1016/j.crohns.2012.08.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/24/2012] [Accepted: 08/24/2012] [Indexed: 02/08/2023]
Abstract
BACKGROUND Collagenous colitis (CC) and lymphocytic colitis (LC) are chronic inflammatory bowel disorders of unknown etiology. This study investigated phenotypic characteristics of the mucosal lymphocytes in CC and LC. METHODS Lamina propria and intraepithelial lymphocytes (LPLs, IELs) isolated from mucosal biopsies from CC (n=7), LC (n=6), as well as LC or CC patients in histopathological remission, (LC-HR) (n=6) and CC-HR (n=4) and non-inflamed controls (n=10) were phenotypically characterized by four-color flow cytometry. RESULTS The proportions of CD8(+) IELs were increased in CC and LC (p<0.01) compared to controls. Increased proportions of CD45RO(+)CD8(+) IELs and LPLs were observed in LC and even more in CC patients (p<0.01). Both CC (p<0.05) and LC patients had elevated proportions of CD4(+)8(+) IELs and LPLs compared to controls. The proportions of CD45RO(+) cells were increased in CD4(+)8(+) IELs and LPLs (p<0.05) in CC and LC patients compared to controls. Both CC (p<0.05) and LC patients had higher proportions of Ki67(+)CD8(+) IELs and LPLs compared to controls. In contrast, decreased proportions of CD4(+) LPLs were observed in CC and LC as well as CD4(+) IELs in LC compared to controls. Increased proportions of Ki67(+)CD4(+) IELs and LPLs (p<0.05) were observed in CC and LC patients. CC-HR but not LC-HR patients demonstrated normalized proportions of both IELs and LPLs compared to CC and LC patients respectively. CONCLUSION LC and CC patients have differences in mucosal lymphocyte subsets, with increased proportions of Ki67(+) and CD45RO(+) CD8(+) and CD4(+)8(+) mucosal T cells.
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11
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Characteristics of reversible absorption-enhancing effect of sodium nitroprusside in rat small intestine. Eur J Pharm Sci 2013; 49:664-70. [DOI: 10.1016/j.ejps.2013.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 05/14/2013] [Accepted: 05/14/2013] [Indexed: 11/15/2022]
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12
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Lee K, Park SK, Kwon BM, Kim K, Yu HE, Ryu J, Oh SJ, Lee KS, Kang JS, Lee CW, Kwon MG, Kim HM. Transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde in Caco-2 cells. Xenobiotica 2010; 39:881-8. [PMID: 19925380 DOI: 10.3109/00498250903216000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde (BCA) was characterized in Caco-2 cells. BCA disappeared rapidly from the donor side without being transported to the receiver side during its absorptive transport across Caco-2 cells. Its metabolites 2'-hydroxycinnamaldehyde (HCA) and o-coumaric acid (OCA) were formed in both the donor and the receiver sides. HCA, in a separate study, also disappeared rapidly from the donor side, mostly being converted to its oxidative metabolite OCA during its absorptive transport across Caco-2 cells. OCA was transported rapidly in the absorptive direction across Caco-2 cells with a P(app) of 25.4 +/- 1.0 x 10(-6) cm s(-1) (mean +/- standard deviation (SD), n = 3). OCA was fully recovered from both the donor and the receiver side throughout the time-course of this study. Formation of HCA from BCA was inhibited almost completely by bis(p-nitrophenyl)phosphate (BNPP), a selective inhibitor of carboxylesterases (CES), and phenylmethylsulfonyl fluoride (PMSF), a broad specificity inhibitor of esterases in Caco-2 cells, suggesting that this hydrolytic biotransformation was likely mediated predominantly by CES. Conversion of HCA to OCA was inhibited significantly by isovanillin, a selective inhibitor of aldehyde oxidase (AO). Inhibitors for xanthine oxidase (XO) and aldehyde dehydrogenase (ALDH), which are known to be involved in the oxidation of aldehydes to carboxylic acids, did not have a significant effect on the biotransformation of HCA to OCA in Caco-2 cells. In summary, the present work demonstrates that BCA is hydrolysed rapidly to HCA, followed by subsequent oxidation to OCA, in Caco-2 cells. The results provide a mechanistic understanding of the poor absorption and low bioavailability of BCA after oral administration.
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Affiliation(s)
- K Lee
- Bio-Evaluation Center, KRIBB, Chungbuk, Republic of Korea
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13
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Pyrogallol-mediated toxicity and natural antioxidants: Triumphs and pitfalls of preclinical findings and their translational limitations. Chem Biol Interact 2010; 183:333-40. [DOI: 10.1016/j.cbi.2009.11.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 11/02/2009] [Accepted: 11/23/2009] [Indexed: 11/20/2022]
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14
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Osaka M, Aoyagi K, Hirakawa A, Nakajima M, Jikuya T, Shigeta O, Sakakibara Y. Comparison of hydroxyl radical generation in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass. Free Radic Res 2009; 40:127-33. [PMID: 16390821 DOI: 10.1080/10715760500428705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We measured the hydroxyl radical (.OH) generation in fourteen patients undergoing coronary artery bypass grafting (CABG), of whom seven patients underwent on-pump CABG with cardiopulmonary bypass (CPB) and seven patients underwent off-pump CABG without CPB. To detect .OH generation, we measured the urinary excretion of .OH products of creatinine (Cr), creatol (CTL; 5-hydroxycreatinine) and methylguanidine (MG) with HPLC using the one point sampling and collected urine during and after the operation. The urinary CTL value corrected urinary Cr value of on-pump CABG significantly increased about 3-5 times from the beginning of CPB to 4 h after operation compared to the baseline value before CPB in both the collected urine and the one point sampling urine. The urinary MG/Cr value in both groups did not change significantly. Significantly increased .OH generation was found during and soon after on-pump CABG.
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Affiliation(s)
- Motoo Osaka
- Graduated School of Comprehensive Human Sciences, University of Tsukuba, and Tsukuba Medical Center Hospital, Department of Cardiovascular Surgery, Tsukuba, Japan
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Bhattacharyya S, Dudeja PK, Tobacman JK. ROS, Hsp27, and IKKbeta mediate dextran sodium sulfate (DSS) activation of IkappaBa, NFkappaB, and IL-8. Inflamm Bowel Dis 2009; 15:673-83. [PMID: 19085995 PMCID: PMC2688460 DOI: 10.1002/ibd.20821] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Dextran sodium sulfate (DSS) is a sulfated polysaccharide that has been very widely used to induce inflammation in experimental models of inflammatory bowel disease in which the effects of pharmacologic and biologic therapies are tested. However, the precise mechanisms by which DSS induces inflammation have not been elucidated. METHODS DSS-induced increases in phospho-IkappaBalpha, nuclear NFkappaB (p65), and IL-8 secretion in human colonic epithelial cells in tissue culture are attributable to a reactive oxygen species (ROS)-induced pathway of inflammation, and do not require TLR4, MyD88, or Bcl10, which are associated with the innate immune pathway of NFkappaB-IL-8 activation. RESULTS DSS-induced increases were inhibited by the ROS scavengers Tempol and Tiron, were associated with decreased phosphorylation of MAPK12 (p38gamma), MAPK 13 (p38delta), and Hsp27, and required the IkappaB kinase (IKK) signalosome component IKKbeta. In ex vivo colonic tissue from TLR4-deficient mice, or following knockdown of MyD88 or Bcl10 or exposure to an IRAK 1/4 inhibitor, DSS effects were not suppressed. Data demonstrated that DSS activates IkappaBalpha, NFkappaB, and IL-8 through an ROS-Hsp27-IKKbeta-mediated pathway, and not through an innate immune cascade. CONCLUSIONS These results suggest that DSS models of inflammation may not be optimal for evaluation of interventions that involve mechanisms of innate immunity.
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Affiliation(s)
| | - Pradeep K. Dudeja
- Department of Medicine, University of Illinois at Chicago, Jesse Brown VAMC, Chicago, Illinois
| | - Joanne K. Tobacman
- Department of Medicine, University of Illinois at Chicago, Jesse Brown VAMC, Chicago, Illinois
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Protective effects of free radical scavenger edaravone against xanthine oxidase-mediated permeability increases in human intestinal epithelial cell monolayer. J Burn Care Res 2009; 30:335-40. [PMID: 19165103 DOI: 10.1097/bcr.0b013e318198a639] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The barrier function of the intestinal mucosa can be disturbed under a variety of pathologic insults. Reactive oxygen species play an important role in intestinal mucosal injury. This in vitro study examines the hypothesis that a free radical scavenger, edaravone (ED), ameliorates gut epithelial permeability increase caused by xanthine oxidase (XO)-mediated oxidative stress in a cell monolayer model. Human intestinal epithelial (HIE) cells were grown as monolayer in bicameral chambers. Twenty milliunits per milliliter of XO+0.25 mM of xanthine (XO+X group) or saline (control) were administered into the basal chambers. Another set of chambers was treated with XO+X and 0.6 mg/ml of ED (XO+X+ED group). The permeability was assessed by quantifying the transepithelial passage of fluorescence in isothiocyanate-labeled dextran. In another series of experiments, Escherichia coli C-25 was also applied in an apical chamber to evaluate the bacterial translocation through the monolayer. The concentration of the fluorescence in isothiocyanate-labeled dextran in the basal chamber of the control group was significantly higher than the control (705 +/- 50.2 vs 155 +/- 45.4 mg/dl, P < .01). Treatment with ED prevented this permeability increase induced by the oxidative stress (P < .01). The incidence of bacterial translocation through the HIE monolayer in XO+X group was also higher than that of the control group (75 vs 13%, P < .05). Increased HIE cell monolayer permeability mediated by xanthine and XO was significantly attenuated with ED. This synthesized radical scavenger may have potential clinical applications against gut mucosal barrier dysfunction.
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17
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Winter S, Konter J, Scheler S, Lehmann J, Fahr A. Permeability changes in response to NONOate and NONOate prodrug derived nitric oxide in a blood-brain barrier model formed by primary porcine endothelial cells. Nitric Oxide 2008; 18:229-39. [PMID: 18284923 DOI: 10.1016/j.niox.2008.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2007] [Revised: 01/22/2008] [Accepted: 01/23/2008] [Indexed: 12/21/2022]
Abstract
The influence of nitric oxide (NO) and NO-donors on the permeability of the blood-brain barrier (BBB) is still not well understood and the literature about this is quite controversial. Some studies suggest increasing, others decreasing or even no effects of NO-donors on the BBB permeability. In this work we report about the influence of three diazeniumdiolates, which release NO spontaneously and three different diazeniumdiolate prodrugs, which have to be cleaved chemically or enzymatically before releasing NO, on the permeability of an in vitro BBB-model formed by primary porcine endothelial cells. By measuring the flux of a small polar molecule (carboxyfluorescein: CF) we could show, that the NO-releasers PHEPIPERAZI/NO (sodium 1-(phenylpiperazin-1-yl)diazen-1-ium-1,2-diolate), DBA/NO (sodium 1-(N,N-dibutylamino)diazen-1-ium-1,2-diolate) and DETA/NO (1-N,N-di-(2-aminoethyl)amino)diazen-1-ium-1,2-diolate) reduced the BBB-model permeability. In contrast, the NO-prodrugs Et-PHEPIPERAZI/NO (O(2)-Ethyl-1-(phenylpiperazin-1-yl)diazen-1-ium-1,2-diolate) and TOSYL-PYRRO/NO (O(2)-(p-Methylbenzen-sulfonyl)-1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate) increased the permeability in all investigated concentrations, whereas the prodrug Et-BUPIPERAZI/NO (O(2)-Ethyl-1-(butylpiperazin-1-yl)diazen-1-ium-1,2-diolate) reduced it at the lowest investigated concentration of 100 microM, at the higher concentrations it increased the permeability. Blocking the effect of the BBB-model permeability reducing compounds could be done by methylene blue, whereas permeability increasing effects could not be blocked.
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Affiliation(s)
- Sven Winter
- Friedrich-Schiller-University Jena, Department of Pharmaceutical Technology, Lessingstrasse 8, 07743 Jena, Germany
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18
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Ding SZ, Minohara Y, Fan XJ, Wang J, Reyes VE, Patel J, Dirden-Kramer B, Boldogh I, Ernst PB, Crowe SE. Helicobacter pylori infection induces oxidative stress and programmed cell death in human gastric epithelial cells. Infect Immun 2007; 75:4030-9. [PMID: 17562777 PMCID: PMC1952011 DOI: 10.1128/iai.00172-07] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Helicobacter pylori infection is associated with altered gastric epithelial cell turnover. To evaluate the role of oxidative stress in cell death, gastric epithelial cells were exposed to various strains of H. pylori, inflammatory cytokines, and hydrogen peroxide in the absence or presence of antioxidant agents. Increased intracellular reactive oxygen species (ROS) were detected using a redox-sensitive fluorescent dye, a cytochrome c reduction assay, and measurements of glutathione. Apoptosis was evaluated by detecting DNA fragmentation and caspase activation. Infection with H. pylori or exposure of epithelial cells to hydrogen peroxide resulted in apoptosis and a dose-dependent increase in ROS generation that was enhanced by pretreatment with inflammatory cytokines. Basal levels of ROS were greater in epithelial cells isolated from gastric mucosal biopsy specimens from H. pylori-infected subjects than in cells from uninfected individuals. H. pylori strains bearing the cag pathogenicity island (PAI) induced higher levels of intracellular oxygen metabolites than isogenic cag PAI-deficient mutants. H. pylori infection and hydrogen peroxide exposure resulted in similar patterns of caspase 3 and 8 activation. Antioxidants inhibited both ROS generation and DNA fragmentation by H. pylori. These results indicate that bacterial factors and the host inflammatory response confer oxidative stress to the gastric epithelium during H. pylori infection that may lead to apoptosis.
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Affiliation(s)
- Song-Ze Ding
- Division of Gastroenterology and Hepatology, Department of Medicine, P.O. Box 800708, Charlottesville, VA 22908-0708, USA
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Yamauchi A, Dohgu S, Nishioku T, Shuto H, Naito M, Tsuruo T, Sawada Y, Kataoka Y. An inhibitory role of nitric oxide in the dynamic regulation of the blood-brain barrier function. Cell Mol Neurobiol 2007; 27:263-70. [PMID: 17318383 DOI: 10.1007/s10571-007-9139-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 06/19/2006] [Indexed: 10/23/2022]
Abstract
1. The present study aimed at elucidating the effect of nitric oxide (NO) on blood-brain barrier (BBB) function with mouse brain capillary endothelial (MBEC4) cells.2. Histamine (20-100 microM) evoked NO production (1.6-7 microM) in MBEC4 cells in a dose-dependent manner.3. The permeability coefficient of sodium fluorescein for MBEC4 cells and the cellular accumulation of rhodamine 123 in MBEC4 cells were increased dose-dependently by the addition of NO solutions (14 and 28 microM) every 10 min during a 30-min period.4. The present study demonstrated that NO increased the permeability and inhibited the P-glycoprotein efflux pump of brain capillary endothelial cells, suggesting that NO plays an inhibitory role in the dynamic regulation of the BBB function.
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Affiliation(s)
- Atsushi Yamauchi
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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20
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Abstract
The discovery that mammalian cells have the ability to synthesize the free radical nitric oxide (NO) has stimulated an extraordinary impetus for scientific research in all the fields of biology and medicine. Since its early description as an endothelial-derived relaxing factor, NO has emerged as a fundamental signaling device regulating virtually every critical cellular function, as well as a potent mediator of cellular damage in a wide range of conditions. Recent evidence indicates that most of the cytotoxicity attributed to NO is rather due to peroxynitrite, produced from the diffusion-controlled reaction between NO and another free radical, the superoxide anion. Peroxynitrite interacts with lipids, DNA, and proteins via direct oxidative reactions or via indirect, radical-mediated mechanisms. These reactions trigger cellular responses ranging from subtle modulations of cell signaling to overwhelming oxidative injury, committing cells to necrosis or apoptosis. In vivo, peroxynitrite generation represents a crucial pathogenic mechanism in conditions such as stroke, myocardial infarction, chronic heart failure, diabetes, circulatory shock, chronic inflammatory diseases, cancer, and neurodegenerative disorders. Hence, novel pharmacological strategies aimed at removing peroxynitrite might represent powerful therapeutic tools in the future. Evidence supporting these novel roles of NO and peroxynitrite is presented in detail in this review.
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Affiliation(s)
- Pál Pacher
- Section on Oxidative Stress Tissue Injury, Laboratory of Physiologic Studies, National Institutes of Health, National Institute of Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA.
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21
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Tagkalidis PP, Gibson PR, Bhathal PS. Microscopic colitis demonstrates a T helper cell type 1 mucosal cytokine profile. J Clin Pathol 2006; 60:382-7. [PMID: 16775121 PMCID: PMC2001106 DOI: 10.1136/jcp.2005.036376] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Microscopic colitis (MC) is an inflammatory disorder of unknown aetiology. AIM To characterise the mucosal cytokine profile of MC, with a view to understanding its potential pathogenic mechanisms. METHODS Cytokine profiles of mucosal biopse specimens taken at flexible sigmoidoscopy from 18 patients (8 with lymphocytic colitis and 10 with collagenous colitis) were analysed using real-time reverse transcriptase-PCR, in comparison with those from 13 aged-matched controls with diarrhoea-predominant irritable bowel syndrome. Biopsy specimens from six patients with histologically documented remission were available for comparative analysis. Biopsy specimens were also taken to determine the cellular expression of cytokine and cytokine-related proteins using immunohistochemistry. RESULTS Mucosal mRNA levels were 100 times greater for interferon (IFN)gamma and interleukin (IL) 15, 60 times greater for tumour necrosis factor alpha, and 35 times greater for inducible nitric oxide synthase in MC compared with controls. Apart from a trend for increased levels of IL10, levels of other T helper cell type 2 (T(H)2) cytokines including IL2 and IL4 were too low to be accurately quantified. Mucosal IFNgamma mRNA levels correlated with the degree of diarrhoea, and returned to normal in remission. The immunohistochemical expression of cell junction proteins E-cadherin and ZO-1 was reduced in active disease. No differences were noted between lymphocytic and collagenous colitis for any of the above parameters. CONCLUSIONS MC demonstrates a T(H)1 mucosal cytokine profile with IFNgamma as the predominantly upregulated cytokine, with concurrent induction of nitric oxide synthase and down regulation of IFNgamma-related cell junction proteins. This pattern is similar to that in coeliac disease and suggests that it might represent a response to a luminal antigen.
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Affiliation(s)
- Peter P Tagkalidis
- Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia.
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22
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Pitsikas N, Zisopoulou S, Sakellaridis N. Nitric oxide donor molsidomine attenuates psychotomimetic effects of the NMDA receptor antagonist MK-801. J Neurosci Res 2006; 84:299-305. [PMID: 16710846 DOI: 10.1002/jnr.20889] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
There is experimental evidence indicating that the non-competitive NMDA receptor antagonist MK-801 impairs cognition and produces a series of schizophrenia-like symptoms in rodents (hypermotility, stereotypies, and ataxia). The present study was designed to investigate the efficacy of the nitric oxide (NO) donor molsidomine in counteracting these MK-801-induced behavioral effects in the rat. In a first study, post-training administration of molsidomine (at 4 but not 2 mg/kg) successfully antagonized MK-801-induced performance deficits in a recognition memory test. In a subsequent study, molsidomine (2 and 4 mg/kg) was shown to be unable to reverse MK-801-induced hypermotility but attenuated stereotypies (continuous movement whole cage, body sway, and head weaving) produced by MK-801. Moreover, at 4 mg/kg this NO donor counteracted MK-801-induced ataxia. Our findings indicate that molsidomine attenuates behavioral effects related to the hypofunction of the NMDA receptor suggesting that NO might be involved in the psychotomimetic effects of non-competitive NMDA receptor antagonists.
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Affiliation(s)
- Nikolaos Pitsikas
- Department of Pharmacology, School of Medicine, University of Thessaly, Larissa, Greece.
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23
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Gookin JL, Chiang S, Allen J, Armstrong MU, Stauffer SH, Finnegan C, Murtaugh MP. NF-kappaB-mediated expression of iNOS promotes epithelial defense against infection by Cryptosporidium parvum in neonatal piglets. Am J Physiol Gastrointest Liver Physiol 2006; 290:G164-74. [PMID: 16123198 DOI: 10.1152/ajpgi.00460.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cryptosporidium sp. parasitizes intestinal epithelium, resulting in enterocyte loss, villous atrophy, and malabsorptive diarrhea. We have shown that mucosal expression of inducible nitric oxide (NO) synthase (iNOS) is increased in infected piglets and that inhibition of iNOS in vitro has no short-term effect on barrier function. NO exerts inhibitory effects on a variety of pathogens; nevertheless, the specific sites of iNOS expression, pathways of iNOS induction, and mechanism of NO action in cryptosporidiosis remain unclear. Using an in vivo model of Cryptosporidium parvum infection, we have examined the location, mechanism of induction, specificity, and consequence of iNOS expression in neonatal piglets. In acute C. parvum infection, iNOS expression predominated in the villous epithelium, was NF-kappaB dependent, and was not restricted to infected enterocytes. Ongoing treatment of infected piglets with a selective iNOS inhibitor resulted in significant increases in villous epithelial parasitism and oocyst excretion but was not detrimental to maintenance of mucosal barrier function. Intensified parasitism could not be attributed to attenuated fluid loss or changes in epithelial proliferation or replacement rate, inasmuch as iNOS inhibition did not alter severity of diarrhea, piglet hydration, Cl- secretion, or kinetics of bromodeoxyuridine-labeled enterocytes. These findings suggest that induction of iNOS represents a nonspecific response of the epithelium that mediates enterocyte defense against C. parvum infection. iNOS did not contribute to the pathogenic sequelae of C. parvum infection.
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Affiliation(s)
- Jody L Gookin
- Department of Molecular Biomedical Sciences, North Carolina State University College of Veterinary Medicine, 4700 Hillsborough St., Raleigh, NC 27606, USA.
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24
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Nagira M, Tomita M, Mizuno S, Kumata M, Ayabe T, Hayashi M. Ischemia/Reperfusion Injury in the Monolayers of Human Intestinal Epithelial Cell Line Caco-2 and Its Recovery by Antioxidants. Drug Metab Pharmacokinet 2006; 21:230-7. [PMID: 16858127 DOI: 10.2133/dmpk.21.230] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We previously established a in vitro system for assessing early ischemia/reperfusion injury using monolayers of human intestinal epithelial cell line Caco-2, in which lipid peroxidation caused by tertiary-butylhydroperoxide (t-BuOOH), a lipid peroxidation inducer, acts as a trigger of the injury. By now, we have shown that superoxide anion participates in the opening of tight junctions (TJ) induced by reoxygenation following the induction of lipid peroxidation by t-BuOOH at a low concentration. The present objectives are to elucidate the dysfunction of P-glycoprotein (P-gp) in addition to the opening of TJ by t-BuOOH at a high concentration condition using rhodamine123 (Rho123) as a P-gp substrate and cyclosporine A (CyA) as a P-gp inhibitor. Also, we compared the inhibition effect of lutein and other compounds such as biliverdin as a radical scavenger on the opening of TJ and the dysfunction of P-gp. t-BuOOH at a high concentration increased the permeability of Rho123 in the apical to basal direction and decreased basal to apical direction when compared with control conditions. t-BuOOH at a high concentration showed no significant difference between directional transport of Rho123 and no inhibition was observed in the permeability of both directions by CyA. The staining intensity of Western blot was decreased by t-BuOOH at a high concentration. Although lutein and the other compounds had recovery effects on the opening of TJ and P-gp dysfunction induced by t-BuOOH, lutein is more advantageous than other compounds since it has effective effects at the lower concentration. In conclusion, the barrier dysfunction such as the inhibition of P-gp in addition to the opening of TJ was induced by t-BuOOH at a high concentration condition. The above two barrier dysfunctions was ameliorated by antioxidant such as lutein and biliverdin.
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Affiliation(s)
- Mayuko Nagira
- Department of Drug Absorption and Pharmacokinetics, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Japan.
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25
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Affiliation(s)
- Kevin W McConnell
- Department of Surgery, Washington University School of Medicine, St. Louis, MO, USA
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26
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Gookin JL, Allen J, Chiang S, Duckett L, Armstrong MU. Local peroxynitrite formation contributes to early control of Cryptosporidium parvum infection. Infect Immun 2005; 73:3929-36. [PMID: 15972479 PMCID: PMC1168623 DOI: 10.1128/iai.73.7.3929-3936.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Revised: 01/24/2005] [Accepted: 03/03/2005] [Indexed: 11/20/2022] Open
Abstract
In intestinal inflammation, mucosal injury is often exacerbated by the reaction of NO with neutrophil-derived superoxide to form the potent oxidant peroxynitrite. Peroxynitrite also has antimicrobial properties that aid in the killing mechanism of macrophages and neutrophils. Cryptosporidium parvum parasitizes intestinal epithelium, resulting in loss of epithelial cells and mucosal inflammation. Synthesis of NO is significantly increased and arises from the induced expression of inducible nitric oxide synthase (iNOS) by the infected epithelium. Inhibition of iNOS results in intensified epithelial parasitism and oocyst excretion. We hypothesized that formation of peroxynitrite is restricted to sites of iNOS expression by the epithelium and contributes to host defense in C. parvum infection. Accordingly, the location and biological effects of peroxynitrite formation were examined in neonatal piglets infected with C. parvum. Infected piglets were treated daily with a selective iNOS inhibitor [L-N6-(1-iminoethyl)-lysine] or one of two peroxynitrite scavengers [5,10,15,20-tetrakis(N-methyl-4'-pyridyl)porphyrinato iron(III) or uric acid] or received vehicle. At peak infection, peroxynitrite formation was restricted to sites of iNOS expression by parasitized epithelium and lamina propria of the apical villi. Peroxynitrite formation was dependent on iNOS activity and was inhibited by treatment with peroxynitrite scavengers. Scavengers increased the number of intracellular parasites and the number of infected epithelial cells present per villus and significantly exacerbated oocyst excretion. Recovery from infection was not delayed by ongoing treatment with scavenger. The present results are the first to demonstrate an in vivo role for peroxynitrite formation in acute mucosal defense against a noninvasive intestinal epithelial pathogen.
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Affiliation(s)
- Jody L Gookin
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.
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27
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Takahashi K, Numata N, Kinoshita N, Utoguchi N, Mayumi T, Mizuno N. Characterization of the influence of nitric oxide donors on intestinal absorption of macromolecules. Int J Pharm 2005; 286:89-97. [PMID: 15501005 DOI: 10.1016/j.ijpharm.2004.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2004] [Revised: 07/01/2004] [Accepted: 08/08/2004] [Indexed: 10/26/2022]
Abstract
To characterize the influence of nitric oxide (NO) donors on the intestinal absorption of macromolecules, the relationship between the release rate of NO from NO donors and their absorption-enhancing effects and the effects of several scavengers and generators on the absorption-enhancing effects of NO donor were investigated. The t1/2 values of the NO release rate from 3-(2-hydroxy-1-methylethyl-2-nitrosohydrazino)-1-propanamine (NOC5), 3-(2-hydroxy-1-methylethyl-2-nitrosohydrazino)-N-methyl-1-propanamine (NOC7) and N-ethyl-2-(1-ethyl-hydroxy-2-nitrosohydrazino)-ethanamine (NOC12) are 25, 5 and 100min, respectively. The absorption-enhancing effects of NO donors on the absorption of fluorescein isothiocyanate dextrans with an average molecular weight of 4400 (FD-4) are NOC5 > NOC7 > NOC12 in the colon. The lowest enhancing effect of NOC12 may be due to the slow rate of NO release. The enhancing effect of NOC7 rapidly disappeared compared with the effect of NOC5. The results raise the possibility that the difference between NOC5 and NOC7 on enhancing effect is related to the t1/2 of the NO release. The NOC7-induced enhancing effect was prevented by the co-administration of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazole-1-oxyl-3-oxide sodium salt (C-PTIO), an NO scavenger; tiron, an O2(-) scavenger; mannitol, an OH* scavenger, and deferoxamine, peroxynitrate scavenger. Pyrogallol, an O2(-) generator, potentiated the NOC7-induced enhancing effect. These results support a role for peroxynitrate, and possibly OH*, in the NO donor-induced intestinal enhancing effect.
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Affiliation(s)
- Koichi Takahashi
- Department of Pharmaceutics, School of Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Koshien, Kyuban-cho, Nishinomiya, Hyogo 663-8179, Japan.
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28
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Fink MP, Delude RL. Epithelial Barrier Dysfunction: A Unifying Theme to Explain the Pathogenesis of Multiple Organ Dysfunction at the Cellular Level. Crit Care Clin 2005; 21:177-96. [PMID: 15781156 DOI: 10.1016/j.ccc.2005.01.005] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The multiple organ dysfunction syndrome (MODS) is the most common cause of death among patients requiring care in an ICU. There is widespread agreement that MODS is the clinical manifestation of a dysregulated inflammatory response. This article, however, summarizes some tantalizing data to support the view that derangements in the formation or function of specialized structures in epithelial cells, tight junctions, may be a key factor leading to lung, liver, gut, and perhaps kidney dysfunction associated with such conditions as sepsis and acute lung injury syndrome that are caused by dysregulated inflammatory processes.
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Affiliation(s)
- Mitchell P Fink
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, 616 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
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29
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Tomita M, Nagira M, Haga M, Hayashi M. Clarification of the mechanism of structural change induced by reoxygenation following the induction of lipid peroxidation in Caco-2 cell monolayers. Drug Metab Pharmacokinet 2005; 17:83-91. [PMID: 15618656 DOI: 10.2133/dmpk.17.83] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently, we established a system for assessing ischemia/reperfusion injury, specifically the opening of tight junctions (TJ), caused by reoxygenation following the induction of lipid peroxidation by tertiary-butylhydroperoxide (t-BuOOH), using the human intestinal epithelial cell line Caco-2 in order to focus on the barrier function of the epithelium independent of the vascular compartment. In the present study, we attempted to identify factors involved in the structural changes induced by reoxygenation using 0.5 mM t-BuOOH in Caco-2 cell monolayers. Glutathione (GSH) and N-acetylcystein, a precursor of GSH, inhibited the opening of TJ evoked by reoxygenation following the induction of lipid peroxidation by 0.5 mM of t-BuOOH. Tiron, as a cell permeable superoxide anion scavenger and deferoxamine, an iron-chelating agent ameliorated the opening in a dose-dependent manner. Also, Tiron suppressed the apical-to-basal and basal-to-apical permeability of the increased Rhodamine123 by reoxygenation in a concentration-dependent manner. These results collectively suggest that superoxide anion and iron ions play an important role or contribute to structural changes such as the opening of TJ induced by reoxygenation following the induction of lipid peroxidation by 0.5 mM t-BuOOH.
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Affiliation(s)
- Mikio Tomita
- Department of Biopharmaceutics, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Tokyo, Japan.
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30
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Dohgu S, Yamauchi A, Nakagawa S, Takata F, Kai M, Egawa T, Naito M, Tsuruo T, Sawada Y, Niwa M, Kataoka Y. Nitric oxide mediates cyclosporine-induced impairment of the blood–brain barrier in cocultures of mouse brain endothelial cells and rat astrocytes. Eur J Pharmacol 2004; 505:51-9. [PMID: 15556136 DOI: 10.1016/j.ejphar.2004.10.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Indexed: 10/26/2022]
Abstract
The present study was designed to clarify the involvement of nitric oxide (NO) signaling in the adverse effect of cyclosporine on the blood-brain barrier. Cyclosporine increased the permeability of sodium-fluorescein and the cellular accumulation of rhodamine 123, a substrate of P-glycoprotein, in mouse brain endothelial (MBEC4) cells. This effect was markedly enhanced two- to threefold when MBEC4 cells were cocultured with rat astrocytes or C6 glioma cells. Direct and continuous electrochemical measurement of NO demonstrated that cyclosporine dose-dependently increased histamine- and phenylephrine-evoked NO production in MBEC4 cells and astrocytes, respectively. A NO synthase inhibitor (NG-monomethyl-L-arginine) blocked slightly and markedly cyclosporine-induced impairment of the endothelial barrier in the monolayer and coculture system, respectively. These findings suggest that cyclosporine impairs the brain endothelial barrier function by accelerating NO production in the brain endothelial and astroglial cells. This event may be interpreted as triggering the occurrence of cyclosporine neurotoxicity.
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Affiliation(s)
- Shinya Dohgu
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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31
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Han X, Fink MP, Yang R, Delude RL. Increased iNOS activity is essential for intestinal epithelial tight junction dysfunction in endotoxemic mice. Shock 2004; 21:261-70. [PMID: 14770040 DOI: 10.1097/01.shk.0000112346.38599.10] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We tested the hypothesis that increased production of nitric oxide (NO.) associated with lipopolysaccharide (LPS)-induced systemic inflammation leads to functionally significant alterations in the expression and/or targeting of key tight junction (TJ) proteins in ileal and colonic epithelium. Wild-type or inducible NO. synthase (iNOS) knockout male C57B1/6J mice were injected intraperitoneally with 2 mg/kg Escherichia coli O111:B4 LPS. iNOS was inhibited using intraperitoneal L-N(6)-(1-iminoethyl)lysine (L-NIL; 5 mg/kg). Immunoblotting of total protein and NP-40 insoluble proteins revealed decreased expression and decreased TJ localization, respectively, of the TJ proteins, zonula occludens (ZO)-1, ZO-2, ZO-3, and/or occludin in ileal mucosa and colonic mucosa (total protein only) after injection of C57B1/6J mice with LPS. Immunohistochemistry showed deranged distribution of ZO-1 and occludin in both tissues from endotoxemic mice. Endotoxemia was associated with evidence of gut epithelial barrier dysfunction evidenced by increased ileal mucosal permeability to fluorescein isothiocyanate-dextran (Mr=4 kDa) and increased bacterial translocation to mesenteric lymph nodes. Pharmacologic inhibition of iNOS activity using L-NIL or genetic ablation of the iNOS gene ameliorated LPS-induced changes in TJ protein expression and gut mucosal barrier function. These results support the view that at least one mechanism contributing to the pathogenesis of gastrointestinal epithelial dysfunction secondary to systemic inflammation is increased iNOS-dependent NO. production leading to altered expression and localization of key TJ proteins.
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Affiliation(s)
- Xiaonan Han
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15261, USA
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32
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Gookin JL, Duckett LL, Armstrong MU, Stauffer SH, Finnegan CP, Murtaugh MP, Argenzio RA. Nitric oxide synthase stimulates prostaglandin synthesis and barrier function in C. parvum-infected porcine ileum. Am J Physiol Gastrointest Liver Physiol 2004; 287:G571-81. [PMID: 15155179 DOI: 10.1152/ajpgi.00413.2003] [Citation(s) in RCA: 31] [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
Cell culture models implicate increased nitric oxide (NO) synthesis as a cause of mucosal hyperpermeability in intestinal epithelial infection. NO may also mediate a multitude of subepithelial events, including activation of cyclooxygenases. We examined whether NO promotes barrier function via prostaglandin synthesis using Cryptosporidium parvum-infected ileal epithelium in residence with an intact submucosa. Expression of NO synthase (NOS) isoforms was examined by real-time RT-PCR of ileal mucosa from control and C. parvum-infected piglets. The isoforms mediating and mechanism of NO action on barrier function were assessed by measuring transepithelial resistance (TER) and eicosanoid synthesis by ileal mucosa mounted in Ussing chambers in the presence of selective and nonselective NOS inhibitors and after rescue with exogenous prostaglandins. C. parvum infection results in induction of mucosal inducible NOS (iNOS), increased synthesis of NO and PGE2, and increased mucosal permeability. Nonselective inhibition of NOS (NG-nitro-L-arginine methyl ester) inhibited prostaglandin synthesis, resulting in further increases in paracellular permeability. Baseline permeability was restored in the absence of NO by exogenous PGE2. Selective inhibition of iNOS [L-N6-(1-iminoethyl)-L-lysine] accounted for approximately 50% of NOS-dependent PGE2 synthesis and TER. Using an entire intestinal mucosa, we have demonstrated for the first time that NO serves as a proximal mediator of PGE2 synthesis and barrier function in C. parvum infection. Expression of iNOS by infected mucosa was without detriment to overall barrier function and may serve to promote clearance of infected enterocytes.
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Affiliation(s)
- Jody L Gookin
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA.
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33
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Roig-Pérez S, Guardiola F, Moretó M, Ferrer R. Lipid peroxidation induced by DHA enrichment modifies paracellular permeability in Caco-2 cells. J Lipid Res 2004; 45:1418-28. [PMID: 15175351 DOI: 10.1194/jlr.m300513-jlr200] [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: 11/20/2022] Open
Abstract
Dietary enrichment with docosahexaenoic acid (DHA) has numerous beneficial effects on health. However, the intake of high doses of polyunsaturated fatty acids can promote lipid peroxidation and the subsequent propagation of oxygen radicals. The purpose of this study was to evaluate the effect of DHA on lipid peroxidation and tight junction structure and permeability in Caco-2 cell cultures. Moreover, the effects of taurine, a functional ingredient with antioxidant properties, were also tested. Differentiated Caco-2 cell monolayers were maintained in DHA-supplemented conditions with or without added taurine. Incubation with 100 microM DHA increased lipid peroxidation and paracellular permeability, in parallel with a redistribution of the tight junction proteins occludin and ZO-1. Taurine partially prevented all of these effects. The participation of reactive oxygen and nitrogen species in increased paracellular permeability was also examined using various agents that modify the formation of superoxide radical, hydrogen peroxide, nitric oxide, and peroxynitrite. We conclude that hydrogen peroxide and peroxynitrite may be involved in the DHA-induced increase in paracellular permeability and that the protective role of taurine may be in part related to its capacity to counteract the effects of hydrogen peroxide.
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Affiliation(s)
- Sònia Roig-Pérez
- Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain
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Abstract
During the past decade, enormous advances have been made in cell biology. Major advances included the publication of the human genome sequence, the development of proteomics, and DNA microarray technologies and techniques to selectively "silence" genes using short strands of double-stranded RNA. Some areas of great progress that are particularly relevant to critical care medicine include huge improvements in our understanding of the signal transduction pathways involved in the innate immune response and adaptation to hypoxia. Other areas of important progress include improvements in our understanding of how inflammation causes derangements in epithelial structure and function and impairs cellular utilization of oxygen.
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Affiliation(s)
- Mitchell P Fink
- Departments of Critical Care Medicine and Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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35
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Al-Ghoul WM, Khan M, Fazal N, Sayeed MM. Mechanisms of postburn intestinal barrier dysfunction in the rat: Roles of epithelial cell renewal, E-cadherin, and neutrophil extravasation*. Crit Care Med 2004; 32:1730-9. [PMID: 15286551 DOI: 10.1097/01.ccm.0000132896.62368.01] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Our group has previously shown that the intestinal epithelium exhibits increased postburn barrier permeability and bacterial translocation associated with deranged neutrophil activity. The purpose of this investigation is to explore possible underlying intestinal structural mechanisms, leading to those functional changes with emphasis on (1) neutrophil influx and extravasation in the intestinal lamina propria 1-3 days after burn and (2) enterocyte proliferation, migration, apoptosis, and E-cadherin junctional epithelium levels 3 days after burn. DESIGN Freshly isolated ileum specimens were quick frozen, then cut by a cryostat into 30-micron-thick sections. Sections from day 1 postburn rats were immunostained with (1) anti-granulocyte or anti-elastase antibodies to assess neutrophil influx or (2) combined anti-granulocyte and anti-von Willebrand factor double immunolabeling to compare levels of neutrophil extravasation. Sections from day 3 postburn rats were immunostained with (1) bromodeoxyuridine immunohistochemistry 1, 3, 6, or 18 hrs after bromodeoxyuridine injection to assess enterocyte proliferation and migration, (2) cytokeratin-18 M30-immunohistochemistry to compare levels of enterocyte apoptosis, and (3) E-cadherin immunohistochemistry to compare junctional E-cadherin integrity. Ileal myeloperoxidase activity and bacterial translocation of Enterococcus faecalis were assessed biochemically and by E. faecalis-specific bacterial cultures, respectively, in day 3 postburn rats. SETTING : Research laboratories in a medical center and an academic institution. SUBJECTS Male Sprague-Dawley rats given sham treatment or treatment as a burn model with full-thickness skin scald over 30% total body surface area. CONCLUSIONS We report (1) increased levels of neutrophil influx and extravasation in villi lamina propriae, including elastase-positive cells (postburn day 1), (2) heightened levels of intestinal myeloperoxidase activity (postburn day 3), (3) decreased levels of epithelial cell proliferation, migration, and E-cadherin (postburn day 3), and (4) increased enterocyte apoptosis and E. faecalis bacterial translocation (postburn day 3). Based on these structural and functional abnormalities, we propose a mechanism for burn injury-related intestinal barrier dysfunction that includes increased trans- and para-cellular leakage caused by impaired enterocyte renewal and decreased junctional E-cadherin levels subsequent to increased neutrophil influx and extravasation within the villus lamina propria microenvironment.
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Affiliation(s)
- Walid M Al-Ghoul
- Trauma/Critical Care Labs, Department of Surgery, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
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Han X, Fink MP, Uchiyama T, Yang R, Delude RL. Increased iNOS activity is essential for pulmonary epithelial tight junction dysfunction in endotoxemic mice. Am J Physiol Lung Cell Mol Physiol 2004; 286:L259-67. [PMID: 12896879 DOI: 10.1152/ajplung.00187.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A murine endotoxemia model and cultured Calu-3 monolayers were used to test the hypothesis that excessive nitric oxide (NO) production secondary to induction of inducible NO synthase (iNOS) is a key factor leading to altered tight junction (TJ) protein expression and function in the pulmonary epithelium. C57Bl/6J mice were injected with either Escherichia coli 0111:B4 lipopolysaccharide (LPS; 2 mg/kg) or vehicle. Twelve hours later, leakage of FITC-dextran (M(r) 4 kDa; FD4) from blood into bronchoalveolar lavage fluid was significantly increased in endotoxemic but not control mice. This decrease in bronchoalveolar barrier function was associated with upregulation of iNOS protein expression and NF-kappaB activation in lung tissue. Expression of the TJ proteins, zonula occludens (ZO)-1, ZO-2, ZO-3, and occludin, as assessed by immunoblotting and/or immunofluorescence, decreased in lung after the injection of mice with LPS. Treatment of endotoxemic mice with an isoform-selective iNOS inhibitor [l-N(6)-(1-iminoethyl)lysine; l-NIL] ameliorated LPS-induced changes in TJ protein expression and preserved bronchoalveolar epithelial barrier function. Incubating Calu-3 bronchiolar epithelial monolayers with cytomix (a mixture of 1,000 U/ml IFN-gamma, 10 ng/ml TNF-alpha, and 1 ng/ml IL-1beta) increased permeability to FD4, but adding l-NIL prevented this effect. These results suggest that decreased expression and mistargeting of TJ proteins in lung after systemic inflammation may be NO dependent.
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Affiliation(s)
- Xiaonan Han
- Department of Critical Care Medicine, 616 Scaife Hall, 3550 Terrace St., Pittsburgh, PA 15261, USA
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Han X, Fink MP, Uchiyama T, Yang R, Delude RL. Increased iNOS activity is essential for hepatic epithelial tight junction dysfunction in endotoxemic mice. Am J Physiol Gastrointest Liver Physiol 2004; 286:G126-36. [PMID: 12946943 DOI: 10.1152/ajpgi.00231.2003] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We tested the hypothesis that increased production of nitric oxide (NO*) by inducible NO* synthase (iNOS) is a key factor responsible for alterations in the expression, localization, and function of key tight junction (TJ) proteins in mice challenged with lipopolysaccharide (LPS, endotoxin). Endotoxemia was associated with hepatobiliary epithelial barrier dysfunction, as evidenced by increased plasma-to-bile leakage of FITC-labeled dextran (relative molecular mass 40 kDa) and increased circulating levels of bile acids and conjugated bilirubin. Immunoblotting revealed decreased expression of zonula occludens (ZO)-1, ZO-2, ZO-3, and occludin in liver after injection of C57Bl/6J mice with 2 mg/kg Escherichia coli 0111:B4 LPS. Nonidet P-40-insoluble (i.e., TJ-associated) occludin and ZO-1 were virtually undetectable 12 and 18 h after injecting LPS. Immunofluorescence microscopy also revealed deranged subcellular localization of ZO-1 and occludin in endotoxemic mice. Pharmacological inhibition of iNOS activity using l-N6-(1-iminoethyl)lysine (5 mg/kg) or genetic ablation of iNOS ameliorated LPS-induced changes in hepatobiliary barrier function, and these strategies partially preserved TJ protein expression and localization. Steady-state levels of occludin and ZO-3 transcripts decreased transiently after injecting LPS but returned toward normal by 12 and 24 h after induction of endotoxemia, respectively. These results support the view that iNOS-dependent NO* production is an important factor contributing to hepatobiliary epithelial barrier dysfunction resulting from systemic inflammation and suggest that iNOS induction may play a role in the development of cholestatic jaundice in patients with severe sepsis.
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Affiliation(s)
- Xiaonan Han
- Deptartment of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Lobo SM, De Backer D, Sun Q, Tu Z, Dimopoulos G, Preiser JC, Nagy N, Vray B, Vercruy V, Terzi RGG, Vincent JL, Tu Z. Gut mucosal damage during endotoxic shock is due to mechanisms other than gut ischemia. J Appl Physiol (1985) 2003; 95:2047-54. [PMID: 12923122 DOI: 10.1152/japplphysiol.00925.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Whether the gut alterations seen during sepsis are caused by microcirculatory hypoxia or disturbances in cellular metabolic pathways associated with mitochondrial respiration remains controversial. We hypothesized that hypoperfusion or hypoxia and local production of nitric oxide might play an important role in the development of gut mucosal injury during endotoxic shock and investigated their roles by using differing levels of fluid resuscitation and occlusion of the superior mesenteric artery (SMA). Anesthetized New Zealand rabbits were allocated to group I (sham, n = 8); group II [low-dose endotoxin (LPS, Escherichia coli-055:B5, 150 microg/kg)/fluid resuscitation (12 ml x kg(-1) x h(-1)); n = 8]; group III [high-dose LPS (1 mg/kg)/fluid resuscitation (12 ml x kg(-1) x h(-1)); n = 8]; group IV [high-dose LPS (1 mg/kg)/hypovolemia (4 ml x kg-1 x h(-1) fluids); n = 8]; and group V [SMA ligation/fluid resuscitation (12 ml x kg(-1) x h(-1)); n = 4]. Luminal gut lactate concentrations and PCO2 gap increased in groups IV and V (P < 0.05), reflecting alterations in gut perfusion. Interestingly, significant histological alterations were observed in all LPS groups but not in group V. Blood and luminal gut nitrate/nitrite concentrations increased only in group IV. The mechanism of gut injury in endotoxic shock seems unrelated to hypoxia and release of nitric oxide. Gut dysfunction may occur as a result of so-called "cytopathic hypoxia."
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Affiliation(s)
- Suzana M Lobo
- Department of Intensive Care, Faculdade de Medicine de Sao José do Rio Preto, Brazil
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Experimental diabetes causes breakdown of the blood-retina barrier by a mechanism involving tyrosine nitration and increases in expression of vascular endothelial growth factor and urokinase plasminogen activator receptor. THE AMERICAN JOURNAL OF PATHOLOGY 2003. [PMID: 12759255 DOI: 10.1016/s0002-9440[10]64332-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The purpose of these experiments was to determine the specific role of reactive oxygen species (ROS) in the blood-retinal barrier (BRB) breakdown that characterizes the early stages of vascular dysfunction in diabetes. Based on our data showing that high glucose increases nitric oxide, superoxide, and nitrotyrosine formation in retinal endothelial cells, we hypothesized that excess formation of ROS causes BRB breakdown in diabetes. Because ROS are known to induce increases in expression of the well-known endothelial mitogen and permeability factor vascular endothelial growth factor (VEGF) we also examined their influence on the expression of VEGF and its downstream target urokinase plasminogen activator receptor (uPAR). After 2 weeks of streptozotocin-induced diabetes, analysis of albumin leakage confirmed a prominent breakdown of the BRB. This permeability defect was correlated with significant increases in the formation of nitric oxide, lipid peroxides, and the peroxynitrite biomarker nitrotyrosine as well as with increases in the expression of VEGF and uPAR. Treatment with a nitric oxide synthase inhibitor (N-omega-nitro-L-arginine methyl ester, 50 mg/kg/day) or peroxynitrite scavenger (uric acid, 160 mg/kg/day) blocked the breakdown in the BRB and prevented the increases in formation of lipid peroxides and tyrosine nitration as well as the increases in expression of VEGF and uPAR. Taken together, these data indicate that early diabetes causes breakdown of the BRB by a mechanism involving the action of reactive nitrogen species in promoting expression of VEGF and uPAR.
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El-Remessy AB, Behzadian MA, Abou-Mohamed G, Franklin T, Caldwell RW, Caldwell RB. Experimental diabetes causes breakdown of the blood-retina barrier by a mechanism involving tyrosine nitration and increases in expression of vascular endothelial growth factor and urokinase plasminogen activator receptor. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:1995-2004. [PMID: 12759255 PMCID: PMC1868147 DOI: 10.1016/s0002-9440(10)64332-5] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/05/2003] [Indexed: 10/18/2022]
Abstract
The purpose of these experiments was to determine the specific role of reactive oxygen species (ROS) in the blood-retinal barrier (BRB) breakdown that characterizes the early stages of vascular dysfunction in diabetes. Based on our data showing that high glucose increases nitric oxide, superoxide, and nitrotyrosine formation in retinal endothelial cells, we hypothesized that excess formation of ROS causes BRB breakdown in diabetes. Because ROS are known to induce increases in expression of the well-known endothelial mitogen and permeability factor vascular endothelial growth factor (VEGF) we also examined their influence on the expression of VEGF and its downstream target urokinase plasminogen activator receptor (uPAR). After 2 weeks of streptozotocin-induced diabetes, analysis of albumin leakage confirmed a prominent breakdown of the BRB. This permeability defect was correlated with significant increases in the formation of nitric oxide, lipid peroxides, and the peroxynitrite biomarker nitrotyrosine as well as with increases in the expression of VEGF and uPAR. Treatment with a nitric oxide synthase inhibitor (N-omega-nitro-L-arginine methyl ester, 50 mg/kg/day) or peroxynitrite scavenger (uric acid, 160 mg/kg/day) blocked the breakdown in the BRB and prevented the increases in formation of lipid peroxides and tyrosine nitration as well as the increases in expression of VEGF and uPAR. Taken together, these data indicate that early diabetes causes breakdown of the BRB by a mechanism involving the action of reactive nitrogen species in promoting expression of VEGF and uPAR.
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Affiliation(s)
- Azza B El-Remessy
- Vascular Biology Center, Medical College of Georgia, Augusta, Georgia 30909, USA
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Abstract
Nitric oxide (NO) is a pleiotropic free radical messenger molecule. There is a large body of evidence that the inducible form of the NO synthase enzyme (iNOS) that is responsible for high-output production of NO from l-arginine is up-regulated in various forms of mucosal inflammation. Consistent with this, multiple detection strategies have demonstrated that iNOS expression, enzymatic activity, and NO production are increased in human inflammatory bowel disease tissues. There is also evidence that the level of iNOS-derived NO correlates well with disease activity in ulcerative colitis, while for Crohn's disease, the results are more variable. A substantial number of animal studies have assessed the role of inducible NO production. While the majority of studies have shown improvement in experimental inflammatory bowel disease with iNOS inhibition, there are also a significant number of reports of exacerbation of disease with inhibitors. Similarly, studies using iNOS-deficient mice in colitis models have shown improvement, worsening, or no effect on disease. The authors suggest that additional studies to assess the role of the competing biochemical pathway, namely the conversion of l-arginine to polyamines via the actions of arginase and ornithine decarboxylase, may provide important new insights into understanding the regulation of mucosal inflammation and inflammatory bowel disease.
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Affiliation(s)
- Raymond K Cross
- Department of Medicine, Division of Gastroenterology, University of Maryland School of Medicine, Baltimore 21201, USA
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Fink MP. Intestinal epithelial hyperpermeability: update on the pathogenesis of gut mucosal barrier dysfunction in critical illness. Curr Opin Crit Care 2003; 9:143-51. [PMID: 12657978 DOI: 10.1097/00075198-200304000-00011] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Tight junctions between adjacent epithelial cells are essential for the maintenance of compositionally distinct fluid compartments in various organs, such as the liver, lungs, kidneys, and intestine. These epithelial organs are commonly affected in the condition known as multiple organ dysfunction syndrome, which can complicate the clinical course of patients with sepsis or other conditions associated with poorly controlled systemic inflammation. The gut serves as a useful model for this problem, and studies using reductionist in vitro models and experiments carried out using laboratory animals are starting to clarify the cellular and biochemical mechanisms that are responsible for intestinal epithelial hyperpermeability secondary to critical illness. RECENT FINDINGS One key factor that has been identified is excessive production of nitric oxide and related species, although other factors, such as increased expression of the cytokine interleukin 6, appear to be important as well. A newly described, cytokine-like molecule, high-mobility group B1, increases permeability of cultured epithelial monolayers in vitro and murine ileal mucosa in vivo. SUMMARY Epithelial dysfunction may be a common final pathway contributing to organ dysfunction in sepsis and other forms of critical illness.
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Affiliation(s)
- Mitchell P Fink
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pennsylvania 15260, USA.
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Han X, Fink MP, Delude RL. Proinflammatory cytokines cause NO*-dependent and -independent changes in expression and localization of tight junction proteins in intestinal epithelial cells. Shock 2003; 19:229-37. [PMID: 12630522 DOI: 10.1097/00024382-200303000-00006] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Intestinal epithelial barrier function is impaired after the exposure of enterocytes to proinflammatory cytokines. The mechanism(s) responsible for this phenomenon remain incompletely understood. We used cultured monolayers of Caco-2 enterocyte-like cells to characterize the effect of cytomix, a mixture of interferon-gamma, tumor necrosis factor-alpha, and interleukin-1beta, on the expression and localization of several tight junctions proteins. Cells were stimulated with cytomix in the presence or absence of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1 -oxyl-3-oxide (cPTIO), an NO* scavenger. Some cells were treated with (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl) amino]diazen-1-ium-1,2-diolate] (DETA-NONOate), an NO* donor. Tight junction protein expression was measured in cellular extracts by Western blotting and localized in cells using immunofluorescence. Steady-state mRNA levels were determined using semi-quantitative reverse-transcription polymerase chain reaction. Incubation of cells with DETA-NONOate or cytomix decreased epithelial barrier function, decreased expression of ZO-1 mRNA, decreased expression of ZO-1, ZO-3, and occludin protein, and increased expression of claudin-1 protein. The effects of cytomix on barrier function and tight junction protein expression were modulated by cPTIO. Cytomix caused incorrect subcellular localization of ZO-1, occludin, and claudin-1, and this was modulated by co-incubation with cPTIO. DETA-NONOate caused similar protein mislocalization as observed with cytomix. The effectiveness of cPTIO in maintaining tight junction protein expression and correct subcellular localization was less apparent at early time points (12 h) compared with later points, suggesting an NO*-independent effect of cytokines on barrier function. Thus, cytomix appears to increase the permeability of Caco-2 monolayers through NO*-dependent and -independent mechanisms that are associated with changes in the expression and/or targeting of proteins involved in tight junction function.
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Affiliation(s)
- Xiaonan Han
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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Kukuruzovic R, Brewster DR, Gray E, Anstey NM. Increased nitric oxide production in acute diarrhoea is associated with abnormal gut permeability, hypokalaemia and malnutrition in tropical Australian aboriginal children. Trans R Soc Trop Med Hyg 2003; 97:115-20. [PMID: 12886817 DOI: 10.1016/s0035-9203(03)90044-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Australian Aboriginal children hospitalized with diarrhoeal disease have severe manifestations with acidosis, hypokalaemia, osmotic diarrhoea and abnormal small bowel permeability. Nitric oxide (NO) production is increased in diarrhoeal disease, but its relationship to mucosal function and diarrhoeal complications is not known. We examined the relationship between NO production and complications of acute diarrhoea in Aboriginal and non-Aboriginal children between February 1998 and February 2000. We enrolled 318 children admitted to Royal Darwin Hospital into one of three groups: acute diarrhoea, non-diarrhoeal controls with no inflammatory illness, and non-diarrhoeal controls with inflammatory illness. Nitric oxide production was measured by urine nitrate-creatinine (NOx/Cr) excretion on a low nitrate diet. Small bowel intestinal permeability was measured by the lactulose-rhamnose (L/R) ratio on a timed blood specimen. The NOx/Cr ratios were markedly elevated in Aboriginal diarrhoeal cases (geometric mean [GM] = 1.23, 95% confidence interval [95% CI] 1.07-1.44), lowest in non-Aboriginal non-inflammatory controls (GM = 0.13, 95% CI 0.10-0.16) and intermediate in all other groups (GM = 0.35, 95% CI 0.28-0.43). Convalescent levels (day 5) in the Aboriginal diarrhoeal group (GM = 1.02, 95% CI 0.82-1.28) were slower to fall than L/R ratios. Multivariate analysis in the diarrhoeal group indicated that high NO production was associated with abnormal permeability, hypokalaemia and malnutrition, but not with the severity of diarrhoea, acidosis or osmotic diarrhoea. We concluded that increased NO production may contribute to impaired mucosal barrier function and hypokalaemia in acute gastroenteritis, which may be the cost of the known gut-protective and antimicrobial effects mediated by NO in acute intestinal inflammation.
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Affiliation(s)
- R Kukuruzovic
- Northern Territory Clinical School, Flinders University, Royal Darwin Hospital, P.O. Box 41326, Casuarina, Darwin, NT 0811, Australia
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Sappington PL, Han X, Yang R, Delude RL, Fink MP. Ethyl pyruvate ameliorates intestinal epithelial barrier dysfunction in endotoxemic mice and immunostimulated caco-2 enterocytic monolayers. J Pharmacol Exp Ther 2003; 304:464-76. [PMID: 12490623 DOI: 10.1124/jpet.102.043182] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ethyl pyruvate (EP) solution ameliorates ileal mucosal hyperpermeability and decreases the expression of several proinflammatory genes in ileal and/or colonic mucosa when it is used instead of Ringer's lactate solution (RLS) to resuscitate mice from hemorrhagic shock. To test the hypothesis that EP can ameliorate gut barrier dysfunction induced by other forms of inflammation, we incubated Caco-2 monolayers for 24 to 48 h with cytomix (a mixture of interferon-gamma, tumor necrosis factor-alpha, and interleukin-1beta) in the presence or absence of graded concentrations of EP or sodium pyruvate. Cytomix increased the permeability of Caco-2 monolayers to fluorescein isothiocyanate-labeled dextran (FD4; average molecular mass 4 kDa), but this effect was inhibited by adding 0.1 to 10 mM EP (but not similar concentrations of sodium pyruvate) to the culture medium. EP inhibited several other cytomix-induced phenomena, including nuclear factor-kappaB activation, inducible nitric oxide synthase mRNA expression, and nitric oxide production. Cytomix altered the expression and localization of the tight junctional proteins, ZO-1 and occludin, but this effect was prevented by EP. Delayed treatment with EP solution instead of RLS ameliorated ileal mucosal hyperpermeability to FD4 and bacterial translocation to mesenteric lymph nodes in mice challenged with lipopolysaccharide (LPS). These data support the view that EP ameliorates cytokine- and/or LPS-induced derangements in intestinal epithelial barrier function.
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Affiliation(s)
- Penny L Sappington
- Department of Critical Care Medicine, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261, USA
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Sappington PL, Yang R, Yang H, Tracey KJ, Delude RL, Fink MP. HMGB1 B box increases the permeability of Caco-2 enterocytic monolayers and impairs intestinal barrier function in mice. Gastroenterology 2002; 123:790-802. [PMID: 12198705 DOI: 10.1053/gast.2002.35391] [Citation(s) in RCA: 246] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS High mobility group (HMG) B1 is a nonhistone nuclear protein that was recently identified as a late-acting mediator of lipopolysaccharide-induced lethality in mice. The proinflammatory actions of HMGB1 have been localized to a region of the molecule called the B box. METHODS To determine whether HMGB1 or B box are capable of causing derangements in intestinal barrier function, we incubated cultured Caco-2 human enterocytic monolayers with recombinant human HMGB1 or a 74-residue truncated form of the protein consisting of the B box domain. RESULTS Both HMGB1 and B box increased the permeability of Caco-2 monolayers to fluorescein isothiocyanate-labeled dextran (FD4) in a time- and dose-dependent fashion. The increase in permeability was reversible following removal of the recombinant protein. Exposure of Caco-2 cells to B box resulted in increased expression of inducible nitric oxide synthase messenger RNA and increased production of NO. When we used various pharmacologic strategies to inhibit NO production or scavenge NO or peroxynitrite (ONOO(-)), we abrogated B box-induced hyperpermeability. Administration of B box to wild-type mice increased both ileal mucosal permeability to FD4 and bacterial translocation to mesenteric lymph nodes. These effects were not observed in inducible nitric oxide synthase knockout mice. CONCLUSIONS These data support the view that HMGB1 and B box are capable of causing alterations in gut barrier function via a mechanism that depends on the formation of NO and ONOO(-).
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Affiliation(s)
- Penny L Sappington
- Department of Critical Care Medicine, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261, USA
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Choi HR, Choi JS, Han YN, Bae SJ, Chung HY. Peroxynitrite scavenging activity of herb extracts. Phytother Res 2002; 16:364-7. [PMID: 12112294 DOI: 10.1002/ptr.904] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Peroxynitrite (ONOO(-)) is a cytotoxicant with strong oxidizing properties toward various cellular constituents, including sulphydryls, lipids, amino acids and nucleotides and can cause cell death, lipid peroxidation, carcinogenesis and aging. The aim of this study was to characterize ONOO(-) scavenging constituents from herbs. Twenty-eight herbs were screened for their ONOO(-) scavenging activities with the use of a fluorometric method. The potency of scavenging activity following the addition of authentic ONOO(-) was in the following order: witch hazel bark > rosemary > jasmine tea > sage > slippery elm > black walnut leaf > Queen Anne's lace > Linden flower. The extracts exhibited dose-dependent ONOO(-) scavenging activities. We found that witch hazel (Hamamelis virginiana L.) bark showed the strongest effect for scavenging ONOO(-) of the 28 herbs. Hamamelitannin, the major active component of witch hazel bark, was shown to have a strong ability to scavenge ONOO(-). It is suggested that hamamelitannin might be developed as an effective peroxynitrite scavenger for the prevention of ONOO(-) involved diseases.
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Affiliation(s)
- Hye Rhi Choi
- College of Pharmacy, Pusan National University, Pusan 609-735, Korea
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Resta-Lenert S, Barrett KE. Enteroinvasive bacteria alter barrier and transport properties of human intestinal epithelium: role of iNOS and COX-2. Gastroenterology 2002; 122:1070-87. [PMID: 11910358 DOI: 10.1053/gast.2002.32372] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS Various invasive pathogens cause diarrhea, but the mechanism(s) are poorly understood. We hypothesized that nitric oxide and prostaglandins might modulate chloride secretory and barrier properties of the infected intestinal epithelium and that diarrhea is caused, in part, by altered expression of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2). METHODS Studies were conducted in human intestinal epithelial cell lines (HT29/cl.19A, Caco-2, and T84). Cells were infected with enteroinvasive Escherichia coli (EIEC 029:NM) or Salmonella dublin (SD), or nonpathogenic, noninvasive bacteria (Streptococcus thermophilus [ST] and Lactobacillus acidophilus [LA]). Infected cells and controls were tested for transepithelial resistance, chloride secretion, prostaglandin E2, guanosine 3',5'-cyclic monophosphate and adenosine 3',5'-cyclic monophosphate, and protein expression. RESULTS Cells infected with EIEC or SD, but not uninfected controls or ST/LA-exposed monolayers, showed a progressive reduction in transepithelial resistance starting at 6-12 hours. Infected HT29/cl.19A and Caco-2 cells, but not T84 cells, also showed an increase in total nitrite. Expression of iNOS, and consequently COX-2, was also increased, followed by increased production of prostaglandins and cyclic nucleotides. Furthermore, basal and stimulated chloride secretory responses to various agonists were enhanced in HT29/cl.19A and Caco-2 cells after infection with enteroinvasive bacteria, and this effect was reversed for some agonists by iNOS or COX-2 inhibitors. Increased expression of cystic fibrosis transmembrane conductance regulator and NKCC1 was also observed in EIEC or SD-infected cells vs. controls, secondary to NO synthase activity. CONCLUSIONS Up-regulation of iNOS and COX-2 by enteroinvasive bacteria can modulate chloride secretion and barrier function in intestinal epithelial cells. Thus, these enzymes represent possible therapeutic targets in infectious diarrhea.
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Affiliation(s)
- Silvia Resta-Lenert
- Department of Medicine, and Biomedical Sciences Ph.D. Program, University of California, San Diego, School of Medicine, San Diego, California, USA.
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Lambert GP, Gisolfi CV, Berg DJ, Moseley PL, Oberley LW, Kregel KC. Selected contribution: Hyperthermia-induced intestinal permeability and the role of oxidative and nitrosative stress. J Appl Physiol (1985) 2002; 92:1750-61; discussion 1749. [PMID: 11896046 DOI: 10.1152/japplphysiol.00787.2001] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to characterize intestinal permeability changes over a range of physiologically relevant body temperatures in vivo and in vitro. Initially, FITC-dextran (4,000 Da), a large fluorescent molecule, was loaded into the small intestine of anesthetized rats. The rats were then maintained at approximately 37 degrees C or heated over 90 min to a core body temperature of approximately 41, approximately 41.5, or approximately 42.5 degrees C. Permeability was greater in the 42.5 degrees C group compared with the 37, 41, or 41.5 degrees C groups. Histological analysis revealed intestinal epithelial damage in heated groups. Everted intestinal sacs were then used to further characterize hyperthermia-induced intestinal permeability and to study the potential role of oxidative and nitrosative stress. Increased permeability to 4,000-Da FITC-dextran in both small intestinal and colonic sacs was observed at a temperature of 41.5-42 degrees C compared with 37 degrees C, along with widespread intestinal epithelial damage. Administration of antioxidant enzyme mimics or a nitric oxide synthase inhibitor did not reduce permeability due to heat stress, and tissue concentrations of a lipid peroxidation product were not altered by heat stress, suggesting that oxidative and nitrosative stress were not likely mediators of this phenomenon in vitro. In conclusion, hyperthermia produced increased permeability and marked intestinal epithelial damage both in vivo and in vitro, suggesting that thermal disruption of epithelial membranes contributes to the intestinal barrier dysfunction manifested with heat stress.
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Affiliation(s)
- G P Lambert
- Department of Exercise Science, The University of Iowa, Iowa City, Iowa 52242-1111, USA
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Liaudet L. Poly(adenosine 5'-diphosphate) ribose polymerase activation as a cause of metabolic dysfunction in critical illness. Curr Opin Clin Nutr Metab Care 2002; 5:175-84. [PMID: 11844985 DOI: 10.1097/00075197-200203000-00010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Poly(adenosine 5'-diphosphate) ribose polymerase is a nuclear enzyme activated in response to genotoxic stress induced by a variety of DNA damaging agents. Several oxygen and nitrogen-centered free radicals, notably peroxynitrite, are strong inducers of DNA damage and poly(adenosine 5'-diphosphate) ribose polymerase activation in vitro and in vivo. Activation of this nuclear enzyme depletes the intracellular stores of its substrate nicotinamide adenine dinucleotide, slowing the rate of glycolysis, mitochondrial electron transport and adenosine triphosphate formation. This process triggers a severe energetic crisis within the cell, leading to acute cell dysfunction and cell necrosis. Poly(adenosine 5'-diphosphate) ribose polymerase also plays an important role in the regulation of inflammatory cascades, through a functional association with various transcription factors and transcription co-activators. Recent works identified this enzyme as a critical mediator of cellular metabolic dysfunction, inflammatory injury, and organ damage in conditions associated with overwhelming oxidative stress, including systemic inflammation, circulatory shock, and ischemia-reperfusion. Accordingly, pharmacological inhibitors of poly(adenosine 5'-diphosphate) ribose polymerase protect against cell death and tissue injury in such conditions, and may therefore represent novel therapeutic tools to limit multiple organ damage and dysfunction in critically ill patients.
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Affiliation(s)
- Lucas Liaudet
- Critical Care Division, Department of Internal Medicine, University Hospital, Lausanne, Switzerland.
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