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Ricciotti E, Castro C, Tang SY, Briggs WTE, West JA, Malik D, Rhoades SD, Meng H, Li X, Lahens NF, Sparks JA, Karlson EW, Weljie AM, Griffin JL, FitzGerald GA. Cyclooxygenase-2, Asymmetric Dimethylarginine, and the Cardiovascular Hazard From Nonsteroidal Anti-Inflammatory Drugs. Circulation 2019; 138:2367-2378. [PMID: 29930022 DOI: 10.1161/circulationaha.118.033540] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Large-scale, placebo-controlled trials established that nonsteroidal anti-inflammatory drugs confer a cardiovascular hazard: this has been attributed to depression of cardioprotective products of cyclooxygenase (COX)-2, especially prostacyclin. An alternative mechanism by which nonsteroidal anti-inflammatory drugs might constrain cardioprotection is by enhancing the formation of methylarginines in the kidney that would limit the action of nitric oxide throughout the vasculature. METHODS Targeted and untargeted metabolomics were used to investigate the effect of COX-2 deletion or inhibition in mice and in osteoarthritis patients exposed to nonsteroidal anti-inflammatory drugs on the l-arginine/nitric oxide pathway. RESULTS Analysis of the plasma and renal metabolome was performed in postnatal tamoxifen-inducible Cox-2 knockout mice, which exhibit normal renal function and blood pressure. This revealed no changes in arginine and methylarginines compared with their wild-type controls. Moreover, the expression of genes in the l-arginine/nitric oxide pathway was not altered in the renal medulla or cortex of tamoxifen inducible Cox-2 knockout mice. Therapeutic concentrations of the selective COX-2 inhibitors, rofecoxib, celecoxib, and parecoxib, none of which altered basal blood pressure or renal function as reflected by plasma creatinine, failed to elevate plasma arginine and methylarginines in mice. Finally, plasma arginine or methylarginines were not altered in osteoarthritis patients with confirmed exposure to nonsteroidal anti-inflammatory drugs that inhibit COX-1 and COX-2. By contrast, plasma asymmetrical dimethylarginine was increased in mice infused with angiotensin II sufficient to elevate blood pressure and impair renal function. Four weeks later, blood pressure, plasma creatinine, and asymmetrical dimethylarginine were restored to normal levels. The increase in asymmetrical dimethylarginine in response to infusion with angiotensin II in celecoxib-treated mice was also related to transient impairment of renal function. CONCLUSIONS Plasma methylarginines are not altered by COX-2 deletion or inhibition but rather are elevated coincident with renal compromise.
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Affiliation(s)
- Emanuela Ricciotti
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Cecilia Castro
- Department of Biochemistry, Cambridge Systems Biology Centre, University of Cambridge, United Kingdom (C.C., W.T.E.B., J.A.W., J.L.G.)
| | - Soon Yew Tang
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - William T E Briggs
- Department of Biochemistry, Cambridge Systems Biology Centre, University of Cambridge, United Kingdom (C.C., W.T.E.B., J.A.W., J.L.G.)
| | - James A West
- Department of Biochemistry, Cambridge Systems Biology Centre, University of Cambridge, United Kingdom (C.C., W.T.E.B., J.A.W., J.L.G.)
| | - Dania Malik
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Seth D Rhoades
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Hu Meng
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Xuanwen Li
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Nicholas F Lahens
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Jeffrey A Sparks
- Department of Medicine, Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (J.A.S., E.W.K.)
| | - Elizabeth W Karlson
- Department of Medicine, Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, MA (J.A.S., E.W.K.)
| | - Aalim M Weljie
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
| | - Julian L Griffin
- Department of Biochemistry, Cambridge Systems Biology Centre, University of Cambridge, United Kingdom (C.C., W.T.E.B., J.A.W., J.L.G.)
| | - Garret A FitzGerald
- Department of Systems Pharmacology and Translational Therapeutics and the Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Philadelphia, PA (E.R., S.Y.T., D.M., S.D.R., H.M., X.L., N.F.L., A.M.W., G.A.F.)
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2
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McKean JS, Murray F, Gibson G, Shewan DA, Tucker SJ, Nixon GF. The cAMP-producing agonist beraprost inhibits human vascular smooth muscle cell migration via exchange protein directly activated by cAMP. Cardiovasc Res 2015; 107:546-55. [PMID: 26092100 PMCID: PMC4540143 DOI: 10.1093/cvr/cvv176] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 06/12/2015] [Indexed: 02/05/2023] Open
Abstract
Aims During restenosis, vascular smooth muscle cells (VSMCs) migrate from the vascular media to the developing neointima. Preventing VSMC migration is therefore a therapeutic target for restenosis. Drugs, such as prostacyclin analogues, that increase the intracellular concentration of cyclic adenosine monophosphate (cAMP) can inhibit VSMC migration, but the mechanisms via which this occurs are unknown. Two main downstream mediators of cAMP are protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac). This study has examined the effects of the prostacyclin analogue beraprost on VSMC migration and investigated the intracellular pathways involved. Methods and results In a chemotaxis chamber, human saphenous vein VSMC migrated towards a platelet-derived growth-factor-BB (PDGF) chemogradient. Incubation with therapeutically relevant concentrations of cAMP-producing agonist beraprost significantly decreased PDGF-induced migration. Direct activation of either PKA or Epac inhibited migration whereas inhibition of PKA did not prevent the anti-migratory effect of beraprost. Direct activation of Epac also prevented hyperplasia in ex vivo serum-treated human veins. Using fluorescence resonance energy transfer, we demonstrated that beraprost activated Epac but not PKA. The mechanisms of this Epac-mediated effect involved activation of Rap1 with subsequent inhibition of RhoA. Cytoskeletal rearrangement at the leading edge of the cell was consequently inhibited. Interestingly, Epac1 was localized to the leading edge of migrating VSMC. Conclusions These results indicate that therapeutically relevant concentrations of beraprost can inhibit VSMC migration via a previously unknown mechanism involving the cAMP mediator Epac. This may provide a novel target that could blunt neointimal formation.
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Affiliation(s)
- Jenny S McKean
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Fiona Murray
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - George Gibson
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Derryck A Shewan
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Steven J Tucker
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Graeme F Nixon
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
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3
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Siiskonen H, Oikari S, Pasonen-Seppänen S, Rilla K. Hyaluronan synthase 1: a mysterious enzyme with unexpected functions. Front Immunol 2015; 6:43. [PMID: 25699059 PMCID: PMC4318391 DOI: 10.3389/fimmu.2015.00043] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/22/2015] [Indexed: 11/13/2022] Open
Abstract
Hyaluronan synthase 1 (HAS1) is one of three isoenzymes responsible for cellular hyaluronan synthesis. Interest in HAS1 has been limited because its role in hyaluronan production seems to be insignificant compared to the two other isoenzymes, HAS2 and HAS3, which have higher enzymatic activity. Furthermore, in most cell types studied so far, the expression of its gene is low and the enzyme requires high concentrations of sugar precursors for hyaluronan synthesis, even when overexpressed in cell cultures. Both expression and activity of HAS1 are induced by pro-inflammatory factors like interleukins and cytokines, suggesting its involvement in inflammatory conditions. Has1 is upregulated in states associated with inflammation, like atherosclerosis, osteoarthritis, and infectious lung disease. In addition, both full length and splice variants of HAS1 are expressed in malignancies like bladder and prostate cancers, multiple myeloma, and malignant mesothelioma. Interestingly, immunostainings of tissue sections have demonstrated the role of HAS1 as a poor predictor in breast cancer, and is correlated with high relapse rate and short overall survival. Utilization of fluorescently tagged proteins has revealed the intracellular distribution pattern of HAS1, distinct from other isoenzymes. In all cell types studied so far, a high proportion of HAS1 is accumulated intracellularly, with a faint signal detected on the plasma membrane and its protrusions. Furthermore, the pericellular hyaluronan coat produced by HAS1 is usually thin without induction by inflammatory agents or glycemic stress and depends on CD44–HA interactions. These specific interactions regulate the organization of hyaluronan into a leukocyte recruiting matrix during inflammatory responses. Despite the apparently minor enzymatic activity of HAS1 under normal conditions, it may be an important factor under conditions associated with glycemic stress like metabolic syndrome, inflammation, and cancer.
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Affiliation(s)
- Hanna Siiskonen
- Department of Dermatology, Kuopio University Hospital, University of Eastern Finland , Kuopio , Finland
| | - Sanna Oikari
- Institute of Biomedicine, University of Eastern Finland , Kuopio , Finland
| | | | - Kirsi Rilla
- Institute of Biomedicine, University of Eastern Finland , Kuopio , Finland
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4
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Stephens EH, Saltarrelli JG, Balaoing LR, Baggett LS, Nandi I, Anderson KM, Morrisett JD, Reardon MJ, Simpson MA, Weigel PH, Olmsted-Davis EA, Davis AR, Grande-Allen KJ. Hyaluronan turnover and hypoxic brown adipocytic differentiation are co-localized with ossification in calcified human aortic valves. Pathol Res Pract 2012; 208:642-50. [PMID: 23017666 PMCID: PMC3496006 DOI: 10.1016/j.prp.2012.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/03/2012] [Accepted: 08/13/2012] [Indexed: 11/18/2022]
Abstract
The calcification process in aortic stenosis has garnered considerable interest but only limited investigation into selected signaling pathways. This study investigated mechanisms related to hypoxia, hyaluronan homeostasis, brown adipocytic differentiation, and ossification within calcified valves. Surgically explanted calcified aortic valves (n=14) were immunostained for markers relevant to these mechanisms and evaluated in the center (NodCtr) and edge (NodEdge) of the calcified nodule (NodCtr), tissue directly surrounding nodule (NodSurr); center and tissue surrounding small "prenodules" (PreNod, PreNodSurr); and normal fibrosa layer (CollFibr). Pearson correlations were determined between staining intensities of markers within regions. Ossification markers primarily localized to NodCtr and NodEdge, along with markers related to hyaluronan turnover and hypoxia. Markers of brown adipocytic differentiation were frequently co-localized with markers of hypoxia. In NodCtr and NodSurr, brown fat and ossification markers correlated with hyaluronidase-1, whereas these markers, as well as hypoxia, correlated with hyaluronan synthases in NodEdge. The protein product of tumor necrosis factor-α stimulated gene-6 strongly correlated with ossification markers and hyaluronidase in the regions surrounding the nodules (NodSurr, PreNodSurr). In conclusion, this study suggests roles for hyaluronan homeostasis and the promotion of hypoxia by cells demonstrating brown fat markers in calcific aortic valve disease.
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Affiliation(s)
| | | | | | | | - Indrajit Nandi
- Department of Bioengineering, Rice University, Houston, TX 77005
| | | | - Joel D. Morrisett
- Departments of Medicine and Biochemistry, Baylor College of Medicine, Houston, TX
| | - Michael J. Reardon
- Department of Cardiovascular Surgery, The Methodist Hospital, Houston, TX 77030
| | | | - Paul H. Weigel
- Department of Biochemistry and Molecular Biology, Oklahoma University Health Science Center, Oklahoma City, OK 73104
| | | | - Alan R. Davis
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX, 77030
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5
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Månsson LE, Montero M, Zarepour M, Bergstrom KS, Ma C, Huang T, Man C, Grassl GA, Vallance BA. MyD88 signaling promotes both mucosal homeostatic and fibrotic responses during Salmonella-induced colitis. Am J Physiol Gastrointest Liver Physiol 2012; 303:G311-23. [PMID: 22679002 DOI: 10.1152/ajpgi.00038.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Salmonella enterica serovar Typhimurium is a clinically important gram-negative, enteric bacterial pathogen that activates several Toll-like receptors (TLRs). While TLR signaling through the adaptor protein MyD88 has been shown to promote inflammation and host defense against the systemic spread of S. Typhimurium, curiously, its role in the host response against S. Typhimurium within the mammalian gastrointestinal (GI) tract is less clear. We therefore used the recently described Salmonella-induced enterocolitis and fibrosis model: wild-type (WT) and MyD88-deficient (MyD88(-/-)) mice pretreated with streptomycin and then orally infected with the ΔaroA vaccine strain of S. Typhimurium. Tissues were analyzed for bacterial colonization, inflammation, and epithelial damage, while fibrosis was assessed by collagen quantification and Masson's trichrome staining. WT and MyD88(-/-) mice carried similar intestinal pathogen burdens to postinfection day 21. Infection of WT mice led to acute mucosal and submucosal inflammation and edema, as well as significant intestinal epithelial damage and proliferation, leading to widespread goblet cell depletion. Impressive collagen deposition in the WT intestine was also evident in the submucosa at postinfection days 7 and 21, with fibrotic regions rich in fibroblasts and collagen. While infected MyD88(-/-) mice showed levels of submucosal inflammation and edema similar to WT mice, they were impaired in the development of mucosal inflammation, along with infection-induced epithelial damage, proliferation, and goblet cell depletion. MyD88(-/-) mouse tissues also had fewer submucosal fibroblasts and 60% less collagen. We noted that cyclooxygenase (Cox)-2 expression was MyD88-dependent, with numerous Cox-2-positive cells identified in fibrotic regions of WT mice at postinfection day 7, but not in MyD88(-/-) mice. Treatment of WT mice with the Cox-2 inhibitor rofecoxib (20 mg/kg) significantly reduced fibroblast numbers and collagen levels without altering colitis severity. In conclusion, MyD88 and Cox-2 signaling play roles in intestinal fibrosis during Salmonella-induced enterocolitis.
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Affiliation(s)
- Lisa E Månsson
- Division of Pediatric Gastroenterology, British Columbia's Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Lee JWY, Lee BS, Lee JY, Ku HJ, Jeon SR, Kim JY, Ban JM, Sung SH, Shin HM, Park JE. The herbal extract HMC05 inhibits neointima formation in balloon-injured rat carotid arteries: possible therapeutic implications of HMC05. JOURNAL OF ETHNOPHARMACOLOGY 2011; 133:168-176. [PMID: 20883768 DOI: 10.1016/j.jep.2010.09.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 08/27/2010] [Accepted: 09/17/2010] [Indexed: 05/29/2023]
Abstract
AIM OF THE STUDY In a previous study, HMC05, a water extract from eight medicinal herbs was demonstrated to possess anti-inflammatory effects in murine macrophages and anti-atherosclerotic effects in apoE(-/-) mice. HSP27 expression was shown to be decreased in advanced atherosclerotic plaques of human carotid arteries. In the present study, the role of HMC05 in the prevention of restenosis and the possible mechanisms involved in the decrease of neointima formation were investigated using in vivo balloon injury rat model and in vitro biochemical assays. MATERIALS AND METHODS A rat carotid artery balloon injury restenosis model was used. Different doses of HMC05 were administered to the rats by tube feeding, starting from four days before surgery and continuing twice per week for two weeks after carotid injury. Injured carotid arteries isolated from rats were embedded in paraffin block and tissue sections were stained with H&E to assess neointima formation. Mechanism by HMC05 that are involved in smooth muscle cell proliferation and migration was assessed by western blot assay, immunohistochemistry and confocal analysis. RESULTS There was no significant difference in the medial area between the control and HMC05-treated groups. However, neointima formation was significantly inhibited in the HMC05-treated group, resulting in 47-fold lower intima to media ratios in rats treated with 25 mg/kg/day HMC05 as compared to the control. Surprisingly, monocytes infiltration in the neointima area was almost completely blocked by HMC05 administration. When rat vascular SMCs were treated with HMC05, the proliferation and migration of smooth muscle cells was dramatically inhibited in a dye uptake assay and in a scratch model in a culture dish, respectively. HMC05 dose-dependently inhibited PDGF-mediated MAPK and AKT activation. However, HMC05 did not affect PDGF-mediated HSP27 phosphorylation but it induced HSP27 overexpression and phosphorylation. In addition, medial SMCs in the arterial wall of rats treated with HMC05 showed a significant increase in HSP27 expression compared with that of the control rats. CONCLUSIONS HMC05, a strong anti-inflammatory reagent, might use HSP27 as an effector molecule in SMCs to reduce neointimal hyperplasia by inhibiting PDGF-mediated MAPK and AKT activation. HMC05 could be a useful drug candidate for the prevention of restenosis after balloon injury of the arteries.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Becaplermin
- Carotid Arteries/drug effects
- Carotid Arteries/metabolism
- Carotid Artery Injuries/pathology
- Catheterization
- Cell Movement/drug effects
- Cell Proliferation/drug effects
- Cells, Cultured
- Coronary Restenosis/prevention & control
- Disease Models, Animal
- HSP27 Heat-Shock Proteins/metabolism
- Humans
- Male
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Neointima/prevention & control
- Phytotherapy
- Plant Extracts/pharmacology
- Plants, Medicinal
- Plaque, Atherosclerotic/pathology
- Plaque, Atherosclerotic/prevention & control
- Platelet-Derived Growth Factor/metabolism
- Proto-Oncogene Proteins c-sis
- Rats
- Signal Transduction
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Affiliation(s)
- Jo Woon Yi Lee
- Division of Cardiology, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
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7
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Guo N, Baglole CJ, O'Loughlin CW, Feldon SE, Phipps RP. Mast cell-derived prostaglandin D2 controls hyaluronan synthesis in human orbital fibroblasts via DP1 activation: implications for thyroid eye disease. J Biol Chem 2010; 285:15794-804. [PMID: 20308056 DOI: 10.1074/jbc.m109.074534] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Thyroid eye disease (TED) is a debilitating disorder characterized by the accumulation of adipocytes and hyaluronan (HA). Production of HA by fibroblasts leads to remarkable increases in tissue volume and to the anterior displacement of the eyes. Prostaglandin D(2) (PGD(2)), mainly produced by mast cells, promotes orbital fibroblast adipogenesis. The mechanism by which PGD(2) influences orbital fibroblasts and their synthesis of HA is poorly understood. We report here that mast cell-derived PGD(2) is a key factor that promotes HA biosynthesis by orbital fibroblasts. Primary orbital fibroblasts from TED patients were isolated and used to test the effects of PGD(2), prostaglandin J(2), as well as prostaglandin D receptor (DP) agonists and antagonists on HA synthesis. The expression of HA synthase (HAS), hyaluronidase, DP1, and DP2 mRNA levels was assessed by PCR. Small interfering RNAs against HAS1 or HAS2 were used to assess the importance of HAS isoforms on HA production. Treatment of human orbital fibroblasts with PGD(2) and PGJ(2) increased HA synthesis and HAS mRNA. HAS2 was the dominant isoform responsible for HA production by PGD(2). The effect of PGD(2) on HA production was mimicked by the selective DP1 agonist BW245C. The DP1 antagonist MK-0524 completely blocked PGD(2)-induced HA synthesis. Human mast cells (HMC-1) produced PGD(2). Co-culture of HMC-1 cells with orbital fibroblasts induced HA production and inhibition of mast cell-derived PGD(2) prevented HA synthesis. Mast cell-derived PGD(2) increased HA production via activation of DP1. Selectively targeting the production of PGD(2) and/or activation of DP1 may prevent pathological changes associated with TED.
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Affiliation(s)
- Naxin Guo
- Department of Ophthalmology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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Ingram KR, Wann AKT, Wingate RM, Coleman PJ, McHale N, Levick JR. Signal pathways regulating hyaluronan secretion into static and cycled synovial joints of rabbits. J Physiol 2009; 587:4361-76. [PMID: 19622607 PMCID: PMC2754372 DOI: 10.1113/jphysiol.2009.175620] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Joint lubrication, synovial fluid conservation and many pathophysiological processes depend on hyaluronan (HA). Intra-articular HA injection and exercise, which stimulates articular HA production, ameliorate osteoarthritis. We therefore investigated the pathways regulating movement-stimulated articular HA secretion rate ( ) in vivo. Endogenous HA was removed from the knee joint cavity of anaesthetised rabbits by washout. Joints were then cycled passively or remained static for 5 h, with/without intra-articular agonist/inhibitor, after which newly secreted HA was harvested for analysis. Movement almost doubled . Similar or larger increases were elicited in static joints by the intra-articular Ca(2+) ionophore ionomycin, prostaglandin E(2), cAMP-raising agents, serine/threonine phosphatase inhibitor and activation of protein kinase C (PKC). PKC-stimulated secretion was inhibited by the PKC inhibitor bisindolylmaleimide I and inhibitors of the downstream kinases MEK-ERK (U0126, PD98059). These agents inhibited movement-stimulated secretion of HA (MSHA) only when the parallel p38 kinase path was simultaneously inhibited by SB203580 (ineffective alone). The phospholipase C inhibitor U73122 almost fully blocked MSHA (P = 0.001, n = 10), without affecting static . The ENaC channel blocker amiloride inhibited MSHA, whereas other inhibitors of stretch-activated channels (Gd(3+), ruthenium red, SKF96365) did not. It is proposed that MSHA may be mediated by PLC activation, leading to activation of parallel PKC-MEK-ERK and p38 kinase pathways.
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Affiliation(s)
- K R Ingram
- Physiology, Basic Medical Sciences, St George's Hospital Medical School, University of London, London SW17 0RE, UK
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