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Lee HN, Hyeon SJ, Kim H, Sim KM, Kim Y, Ju J, Lee J, Wang Y, Ryu H, Seong J. Decreased FAK activity and focal adhesion dynamics impair proper neurite formation of medium spiny neurons in Huntington's disease. Acta Neuropathol 2022; 144:521-536. [PMID: 35857122 DOI: 10.1007/s00401-022-02462-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/11/2022] [Accepted: 06/25/2022] [Indexed: 11/29/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a polyglutamine expansion in the protein huntingtin (HTT) [55]. While the final pathological consequence of HD is the neuronal cell death in the striatum region of the brain, it is still unclear how mutant HTT (mHTT) causes synaptic dysfunctions at the early stage and during the progression of HD. Here, we discovered that the basal activity of focal adhesion kinase (FAK) is severely reduced in a striatal HD cell line, a mouse model of HD, and the human post-mortem brains of HD patients. In addition, we observed with a FRET-based FAK biosensor [59] that neurotransmitter-induced FAK activation is decreased in HD striatal neurons. Total internal reflection fluorescence (TIRF) imaging revealed that the reduced FAK activity causes the impairment of focal adhesion (FA) dynamics, which further leads to the defect in filopodial dynamics causing the abnormally increased number of immature neurites in HD striatal neurons. Therefore, our results suggest that the decreased FAK and FA dynamics in HD impair the proper formation of neurites, which is crucial for normal synaptic functions [52]. We further investigated the molecular mechanism of FAK inhibition in HD and surprisingly discovered that mHTT strongly associates with phosphatidylinositol 4,5-biphosphate, altering its normal distribution at the plasma membrane, which is crucial for FAK activation [14, 60]. Therefore, our results provide a novel molecular mechanism of FAK inhibition in HD along with its pathological mechanism for synaptic dysfunctions during the progression of HD.
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Affiliation(s)
- Hae Nim Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Department of Converging Science and Technology, Kyung Hee University, Seoul, 02453, Republic of Korea
| | - Seung Jae Hyeon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Heejung Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Department of Converging Science and Technology, Kyung Hee University, Seoul, 02453, Republic of Korea
| | - Kyoung Mi Sim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Yunha Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Jeongmin Ju
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Junghee Lee
- Department of Neurology, Boston University Alzheimer's Disease Center, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, CA, 92093, USA
| | - Hoon Ryu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
| | - Jihye Seong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
- Department of Converging Science and Technology, Kyung Hee University, Seoul, 02453, Republic of Korea.
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea.
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Servant NB, Williams ME, Brust PF, Tang H, Wong MS, Chen Q, Lebl-Rinnova M, Adamski-Werner SL, Tachdjian C, Servant G. A Dynamic Mass Redistribution Assay for the Human Sweet Taste Receptor Uncovers G-Protein Dependent Biased Ligands. Front Pharmacol 2022; 13:832529. [PMID: 35250580 PMCID: PMC8893300 DOI: 10.3389/fphar.2022.832529] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/24/2022] [Indexed: 12/26/2022] Open
Abstract
The sweet taste receptor is rather unique, recognizing a diverse repertoire of natural or synthetic ligands, with a surprisingly large structural diversity, and with potencies stretching over more than six orders of magnitude. Yet, it is not clear if different cell-based assays can faithfully report the relative potencies and efficacies of these molecules. Indeed, up to now, sweet taste receptor agonists have been almost exclusively characterized using cell-based assays developed with overexpressed and promiscuous G proteins. This non-physiological coupling has allowed the quantification of receptor activity via phospholipase C activation and calcium mobilization measurements in heterologous cells on a FLIPR system, for example. Here, we developed a novel assay for the human sweet taste receptor where endogenous G proteins and signaling pathways are recruited by the activated receptor. The effects of several sweet taste receptor agonists and other types of modulators were recorded by measuring changes in dynamic mass redistribution (DMR) using an Epic® reader. Potency and efficacy values obtained in the DMR assay were compared to those results obtained with the classical FLIPR assay. Results demonstrate that for some ligands, the two assay systems provide similar information. However, a clear bias for the FLIPR assay was observed for one third of the agonists evaluated, suggesting that the use of non-physiological coupling may influence the potency and efficacy of sweet taste receptor ligands. Replacing the promiscuous G protein with a chimeric G protein containing the C-terminal tail 25 residues of the physiologically relevant G protein subunit Gαgustducin reduced or abrogated bias.
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Johnson K, Yin J, In JG, Kulkarni S, Pasricha P, Tse CM, Donowitz M. Cholinergic-induced anion secretion in murine jejunal enteroids involves synergy between muscarinic and nicotinic pathways. Am J Physiol Cell Physiol 2020; 319:C321-C330. [PMID: 32551856 PMCID: PMC7500216 DOI: 10.1152/ajpcell.00179.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 01/22/2023]
Abstract
Acetylcholine induces robust electrogenic anion secretion in mammalian intestine and it has long been hypothesized that it mediates the epithelial response through the M3 and, to a lesser extent, the M1 muscarinic receptors in the mouse. However, nicotinic receptors have recently been identified in intestinal enterocytes by quantitative real-time (qRT)-PCR/RNAseq, although any direct influence on intestinal transport has not been identified. We tested the hypothesis that cholinergic-induced anion secretion in the intestine is a result of both muscarinic and nicotinic pathways that are intrinsic to the intestinal epithelia. We developed a method to generate mouse jejunal enteroid monolayers which were used to measure active electrogenic anion secretion by the Ussing chamber/voltage-clamp technique. Here, we show that the cholinergic agonist carbachol (CCh) and the muscarinic agonist bethanechol (BCh) stimulate short-lived, concentration-dependent anion secretion in the epithelial cell-only enteroid monolayers. The muscarinic antagonist atropine completely inhibited CCh- and BCh-induced secretion, while the nicotinic antagonist hexamethonium reduced the CCh response by ~45%. While nicotine alone did not alter anion secretion, it increased the BCh-induced increase in short-circuit current in a concentration-dependent manner; this synergy was prevented by pretreatment with hexamethonium. In addition to being sensitive to hexamethonium, monolayers express both classes of cholinergic receptor by qRT-PCR, including 13 of 16 nicotinic receptor subunits. Our findings indicate that an interaction between muscarinic and nicotinic agonists synergistically stimulates anion secretion in mouse jejunal epithelial cells and identify a role for epithelial nicotinic receptors in anion secretion.
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Affiliation(s)
- Kelli Johnson
- Department of Cellular and Molecular Physiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Jianyi Yin
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Julie G In
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Subhash Kulkarni
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Pankaj Pasricha
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Chung Ming Tse
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
| | - Mark Donowitz
- Department of Cellular and Molecular Physiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland
- Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland
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Pelissier-Rota M, Chartier NT, Bonaz B, Jacquier-Sarlin MR. A crosstalk between muscarinic and CRF2 receptors regulates cellular adhesion properties of human colon cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1246-1259. [PMID: 28432022 DOI: 10.1016/j.bbamcr.2017.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 04/04/2017] [Accepted: 04/14/2017] [Indexed: 12/24/2022]
Abstract
Patients with inflammatory bowel disease often suffer from chronic and relapsing intestinal inflammation that favor the development of colitis associated cancer. An alteration of the epithelial intestinal barrier function observed in IBD is supposed to be a consequence of stress. It has been proposed that corticotrophin-releasing factor receptor (CRF2), one of the two receptors of CRF, the principal neuromediator of stress, acts on cholinergic nerves to induce stress-mediated epithelial barrier dysfunction. Non-neuronal acetylcholine (Ach) and muscarinic receptors (mAchR) also contribute to alterations of epithelial cell functions. In this study, we investigated the mechanisms through which stress and Ach modulate epithelial cell adhesive properties. We show that Ach-induced activation of mAchR in HT-29 cells results in cell dissociation together with changes in cell-matrix contacts, which correlates with the acquisition of invasive potential consistent with a matrix metalloproteinase (MMP) mode of invasion. These processes result from mAchR subsequent stimulation of the cascade of src/Erk and FAK activation. Ach-induced secretion of laminin 332 leads to α3β1 integrin activation and RhoA-dependent reorganization of the actin cytoskeleton. We show that Ach-mediated effects on cell adhesion are blocked by astressin 2b, a CRF2 antagonist, suggesting that Ach action depends partly on CRF2 signaling. This is reinforced by the fact that Ach-mediated activation of mAchR stimulates both the synthesis and the release of CRF2 ligands in HT-29 cells (effects blocked by atropine). In summary, our data provides evidence for a novel intracellular circuit involving mAchR acting on CRF2-signaling that could mediate colonic mucosal barrier dysfunction and exacerbate mucosal inflammation.
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Affiliation(s)
- M Pelissier-Rota
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France
| | - N T Chartier
- Biotechnology Center, Technical University Dresden, 01307 Dresden, Germany
| | - B Bonaz
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France; CHU, Grenoble, F-38000 Grenoble, France
| | - M R Jacquier-Sarlin
- Université Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France; INSERM U1216, F-38000 Grenoble, France.
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5
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Khan RI, Yazawa T, Anisuzzaman ASM, Semba S, Ma Y, Uwada J, Hayashi H, Suzuki Y, Ikeuchi H, Uchino M, Maemoto A, Muramatsu I, Taniguchi T. Activation of focal adhesion kinase via M1 muscarinic acetylcholine receptor is required in restitution of intestinal barrier function after epithelial injury. Biochim Biophys Acta Mol Basis Dis 2013; 1842:635-45. [PMID: 24365239 DOI: 10.1016/j.bbadis.2013.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 11/26/2013] [Accepted: 12/16/2013] [Indexed: 12/24/2022]
Abstract
Impairment of epithelial barrier is observed in various intestinal disorders including inflammatory bowel diseases (IBD). Numerous factors may cause temporary damage of the intestinal epithelium. A complex network of highly divergent factors regulates healing of the epithelium to prevent inflammatory response. However, the exact repair mechanisms involved in maintaining homeostatic intestinal barrier integrity remain to be clarified. In this study, we demonstrate that activation of M1 muscarinic acetylcholine receptor (mAChR) augments the restitution of epithelial barrier function in T84 cell monolayers after ethanol-induced epithelial injury, via ERK-dependent phosphorylation of focal adhesion kinase (FAK). We have shown that ethanol injury decreased the transepithelial electrical resistance (TER) along with the reduction of ERK and FAK phosphorylation. Carbachol (CCh) increased ERK and FAK phosphorylation with enhanced TER recovery, which was completely blocked by either MT-7 (M1 antagonist) or atropine. The CCh-induced enhancement of TER recovery was also blocked by either U0126 (ERK pathway inhibitor) or PF-228 (FAK inhibitor). Treatment of T84 cell monolayers with interferon-γ (IFN-γ) impaired the barrier function with the reduction of FAK phosphorylation. The CCh-induced ERK and FAK phosphorylation were also attenuated by the IFN-γ treatment. Immunological and binding experiments exhibited a significant reduction of M1 mAChR after IFN-γ treatment. The reduction of M1 mAChR in inflammatory area was also observed in surgical specimens from IBD patients, using immunohistochemical analysis. These findings provide important clues regarding mechanisms by which M1 mAChR participates in the maintenance of intestinal barrier function under not only physiological but also pathological conditions.
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Affiliation(s)
- Rafiqul Islam Khan
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa, Japan; Department of Pharmacy, University of Rajshahi, Rajshahi, Bangladesh
| | - Takashi Yazawa
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa, Japan
| | | | - Shingo Semba
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa, Japan
| | - Yanju Ma
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang, China
| | - Junsuke Uwada
- Division of Pharmacology, Department of Biochemistry and Bioinformative Sciences, University of Fukui, Fukui, Japan
| | - Hisayoshi Hayashi
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yuichi Suzuki
- Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan; Division of Health and Nutrition, Sendai Shirayuri Women's College, Sendai, Japan
| | - Hiroki Ikeuchi
- Inflammatory Bowel Disease Center, Hyogo College of Medicine, Nishinomiya, Japan
| | - Motoi Uchino
- Inflammatory Bowel Disease Center, Hyogo College of Medicine, Nishinomiya, Japan
| | - Atsuo Maemoto
- Department of Gastrointestinal Immunology and Regenerative Medicine, Asahikawa Medical University, Asahikawa, Japan; Inflammatory Bowel Disease Center, Sapporo Higashi Tokushukai Hospital, Sapporo, Japan
| | - Ikunobu Muramatsu
- Division of Pharmacology, Department of Biochemistry and Bioinformative Sciences, University of Fukui, Fukui, Japan; Organization for Life Science Advancement Programs, University of Fukui, Fukui, Japan; Research Center for Child Mental Development, University of Fukui, Fukui, Japan
| | - Takanobu Taniguchi
- Division of Cellular Signal Transduction, Department of Biochemistry, Asahikawa Medical University, Asahikawa, Japan.
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Bai X, Wang J, Zhang L, Ma J, Zhang H, Xia S, Zhang M, Ma X, Guo Y, Rong R, Cheng S, Shu W, Wang Y, Leng J. Prostaglandin E₂ receptor EP1-mediated phosphorylation of focal adhesion kinase enhances cell adhesion and migration in hepatocellular carcinoma cells. Int J Oncol 2013; 42:1833-41. [PMID: 23525457 DOI: 10.3892/ijo.2013.1859] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/04/2013] [Indexed: 12/20/2022] Open
Abstract
The prostaglandin E₂ (PGE₂) EP1 receptor has been implicated in hepatocellular carcinoma (HCC) cell invasion. However, little is known about the mechanisms of EP1 receptor-mediated cell adhesion and migration. We previously showed that PGE₂ promotes cell adhesion and migration by activating focal adhesion kinase (FAK). The present study was designed to elucidate the association between the EP1 receptor and FAK activation in HCC cells and to investigate the related signaling pathways. The effects of PGE₂, EP1 agonist 17-phenyl trinor-PGE₂ (17-PT-PGE₂), PKC and EGFR inhibitors on FAK activation were investigated by treatment of Huh-7 cells. Phosphorylation of FAK Y397 and c-Src Y416 was investigated by western blotting. Cell adhesion and migration were analyzed by WST and transwell assays, respectively. Protein kinase C (PKC) activity was measured with a PKC assay kit. The results showed that 17-PT-PGE₂ (3 µM) increased FAK Y397 phosphorylation by more than 2-fold and promoted cell adhesion and migration in Huh-7 cells. In transfected 293 cells, expression of the EP1 receptor was confirmed to upregulate FAK phosphorylation, while the EP1 receptor antagonist sc-19220 decreased PGE₂-mediated FAK activation. PKC activity and c-Src Y416 phosphorylation were enhanced after 17-PT-PGE₂ treatment. Both PKC and c-Src inhibitor suppressed the 17-PT-PGE₂-upregulated FAK phosphorylation, as well as 17-PT-PGE₂-induced cell adhesion and migration. In addition, exogenous epidermal growth factor (EGF) treatment increased FAK phosphorylation. The EGF receptor (EGFR) inhibitor also suppressed 17-PT-PGE₂-upregulated FAK phosphorylation. Our study suggests that the PGE₂ EP1 receptor regulates FAK phosphorylation by activating the PKC/c-Src and EGFR signal pathways, which may coordinately regulate adhesion and migration in HCC.
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Affiliation(s)
- Xiaoming Bai
- Cancer Center, Department of Pathology, Nanjing Medical University, Nanjing 210029, PR China
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Nathanson NM. Synthesis, trafficking, and localization of muscarinic acetylcholine receptors. Pharmacol Ther 2008; 119:33-43. [PMID: 18558434 DOI: 10.1016/j.pharmthera.2008.04.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/28/2008] [Indexed: 12/27/2022]
Abstract
Muscarinic acetylcholine receptors are members of the G-protein coupled receptor superfamily that are expressed in and regulate the function of neurons, cardiac and smooth muscle, glands, and many other cell types and tissues. The correct trafficking of membrane proteins to the cell surface and their subsequent localization at appropriate sites in polarized cells are required for normal cellular signaling and physiological responses. This review will summarize work on the synthesis and trafficking of muscarinic receptors to the plasma membrane and their localization at the cell surface.
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Affiliation(s)
- Neil M Nathanson
- Department of Pharmacology, School of Medicine, University of Washington, Box 357750, Seattle, WA 98195-7750, USA.
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8
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Lin AL, Zhu B, Zhang W, Dang H, Zhang BX, Katz MS, Yeh CK. Distinct pathways of ERK activation by the muscarinic agonists pilocarpine and carbachol in a human salivary cell line. Am J Physiol Cell Physiol 2008; 294:C1454-64. [PMID: 18385290 DOI: 10.1152/ajpcell.00151.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cholinergic-muscarinic receptor agonists are used to alleviate mouth dryness, although the cellular signals mediating the actions of these agents on salivary glands have not been identified. We examined the activation of ERK1/2 by two muscarinic agonists, pilocarpine and carbachol, in a human salivary cell line (HSY). Immunoblot analysis revealed that both agonists induced transient activation of ERK1/2. Whereas pilocarpine induced phosphorylation of the epidermal growth factor (EGF) receptor, carbachol did not. Moreover, ERK activation by pilocarpine, but not carbachol, was abolished by the EGF receptor inhibitor AG-1478. Downregulation of PKC by prolonged treatment of cells with the phorbol ester PMA diminished carbachol-induced ERK phosphorylation but had no effect on pilocarpine responsiveness. Depletion of intracellular Ca2+ ([Ca2+]i by EGTA did not affect ERK activation by either agent. In contrast to carbachol, pilocarpine did not elicit [Ca2+]i mobilization in HSY cells. Treatment of cells with the muscarinic receptor subtype 3 (M3) antagonist N-(3-chloropropyl)-4-piperidnyl diphenylacetate decreased ERK responsiveness to both agents, whereas the subtype 1 (M1) antagonist pirenzepine reduced only the carbachol response. Stimulation of ERKs by pilocarpine was also decreased by M3, but not M1, receptor small interfering RNA. The Src inhibitor PP2 blocked pilocarpine-induced ERK activation and EGF receptor phosphorylation, without affecting ERK activation by carbachol. Our results demonstrate that the actions of pilocarpine and carbachol in salivary cells are mediated through two distinct signaling mechanisms-pilocarpine acting via M3 receptors and Src-dependent transactivation of EGF receptors, and carbachol via M1/M3 receptors and PKC-converging on the ERK pathway.
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Affiliation(s)
- Alan L Lin
- Department of Dental Diagnostic Science, University of Texas Health Science Center, San Antonio, TX, USA
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Jin YP, Korin Y, Zhang X, Jindra PT, Rozengurt E, Reed EF. RNA interference elucidates the role of focal adhesion kinase in HLA class I-mediated focal adhesion complex formation and proliferation in human endothelial cells. THE JOURNAL OF IMMUNOLOGY 2007; 178:7911-22. [PMID: 17548629 DOI: 10.4049/jimmunol.178.12.7911] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ligation of class I molecules by anti-HLA Ab stimulates an intracellular signaling cascade resulting in endothelial cell (EC) survival and proliferation, and has been implicated in the process of chronic allograft rejection and transplant-associated vasculopathy. In this study, we used small interfering RNA blockade of focal adhesion kinase (FAK) protein to determine its role in class I-mediated organization of the actin cytoskeleton, cell survival, and cell proliferation in primary cultures of human aortic EC. Knockdown of FAK appreciably inhibited class I-mediated phosphorylation of Src at Tyr(418), p85 PI3K, and Akt at both Thr(308) and Ser(473) sites. FAK knockdown also reduced class I-mediated phosphorylation of paxillin at Try(118) and blocked class I-induced paxillin assembly into focal contacts. FAK small interfering RNA completely abrogated class I-mediated formation of actin stress fibers. Interestingly, FAK knockdown did not modify fibroblast growth factor receptor expression induced by class I ligation. However, FAK knockdown blocked HLA class I-stimulated cell cycle proliferation in the presence and absence of basic fibroblast growth factor. This study shows that FAK plays a critical role in class I-induced cell proliferation, cell survival, and focal adhesion assembly in EC and may promote the development of transplant-associated vasculopathy.
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Affiliation(s)
- Yi-Ping Jin
- Department of Pathology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA 90095, USA
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Jin EJ, Choi YA, Kyun Park E, Bang OS, Kang SS. MMP-2 functions as a negative regulator of chondrogenic cell condensation via down-regulation of the FAK-integrin beta1 interaction. Dev Biol 2007; 308:474-84. [PMID: 17604018 DOI: 10.1016/j.ydbio.2007.06.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 05/31/2007] [Accepted: 06/05/2007] [Indexed: 11/29/2022]
Abstract
Matrix metalloprotease-2 (MMP-2) has the capacity to degrade cartilage extracellular matrix molecules, the turnover of which is an essential event in chondrogenesis. Here, we investigated the functional role of MMP-2 in chondrogenesis of leg bud mesenchymal cells. Small interference RNA (siRNA)-mediated knockdown of mmp-2 promoted precartilage condensation and chondrogenesis. Treatment with bafilomycin A1, an MMP-2 activator, or GM6001, an MMP inhibitor, at the pre-condensation stage resulted in the inhibition or promotion of chondrogenesis, respectively. By comparison, treatment at the post-condensation stage had little or no effect on chondrogenesis. These results indicate that MMP-2 is involved in the regulation of cell condensation. Inhibition of MMP-2 activity by mmp-2 specific siRNA increased the protein level of fibronectin, and integrins alpha5 and beta1. The interaction between focal adhesion kinase (FAK) and integrin beta1 leading to tyrosine phosphorylation of FAK was also enhanced. Moreover, inactivation of p38MAPK down-regulated the level of MMP-2 mRNA and activity, and increased mesenchymal cell condensation in parallel with enhanced phosphorylation of FAK. Taken together, our data indicate that MMP-2 mediates the inhibitory signals of p38MAPK during mesenchymal cell condensation by functioning as a negative regulator of focal adhesion activity regulated by FAK via interactions with fibronectin through integrin beta1.
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Affiliation(s)
- Eun-Jung Jin
- Department of Biology, College of Natural Sciences (BK21), Daegu 702-701, Korea
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11
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Ando S, Otani H, Yagi Y, Kawai K, Araki H, Fukuhara S, Inagaki C. Proteinase-activated receptor 4 stimulation-induced epithelial-mesenchymal transition in alveolar epithelial cells. Respir Res 2007; 8:31. [PMID: 17433115 PMCID: PMC1855055 DOI: 10.1186/1465-9921-8-31] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 04/16/2007] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Proteinase-activated receptors (PARs; PAR1-4) that can be activated by serine proteinases such as thrombin and neutrophil catepsin G are known to contribute to the pathogenesis of various pulmonary diseases including fibrosis. Among these PARs, especially PAR4, a newly identified subtype, is highly expressed in the lung. Here, we examined whether PAR4 stimulation plays a role in the formation of fibrotic response in the lung, through alveolar epithelial-mesenchymal transition (EMT) which contributes to the increase in myofibroblast population. METHODS EMT was assessed by measuring the changes in each specific cell markers, E-cadherin for epithelial cell, alpha-smooth muscle actin (alpha-SMA) for myofibroblast, using primary cultured mouse alveolar epithelial cells and human lung carcinoma-derived alveolar epithelial cell line (A549 cells). RESULTS Stimulation of PAR with thrombin (1 U/ml) or a synthetic PAR4 agonist peptide (AYPGKF-NH2, 100 muM) for 72 h induced morphological changes from cobblestone-like structure to elongated shape in primary cultured alveolar epithelial cells and A549 cells. In immunocytochemical analyses of these cells, such PAR4 stimulation decreased E-cadherin-like immunoreactivity and increased alpha-SMA-like immunoreactivity, as observed with a typical EMT-inducer, tumor growth factor-beta (TGF-beta). Western blot analyses of PAR4-stimulated A549 cells also showed similar changes in expression of these EMT-related marker proteins. Such PAR4-mediated changes were attenuated by inhibitors of epidermal growth factor receptor (EGFR) kinase and Src. PAR4-mediated morphological changes in primary cultured alveolar epithelial cells were reduced in the presence of these inhibitors. PAR4 stimulation increased tyrosine phosphorylated EGFR or tyrosine phosphorylated Src level in A549 cells, and the former response being inhibited by Src inhibitor. CONCLUSION PAR4 stimulation of alveolar epithelial cells induced epithelial-mesenchymal transition (EMT) as monitored by cell shapes, and epithelial or myofibroblast marker at least partly through EGFR transactivation via receptor-linked Src activation.
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Affiliation(s)
- Seijitsu Ando
- Department of Pharmacology, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
- The First Department of Internal Medicine, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
| | - Hitomi Otani
- Department of Pharmacology, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
| | - Yasuhiro Yagi
- The First Department of Internal Medicine, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
| | - Kenzo Kawai
- Fuso Pharmaceutical Industries, Ltd., Joto-ku, Osaka 536-8523, Japan
| | - Hiromasa Araki
- Fuso Pharmaceutical Industries, Ltd., Joto-ku, Osaka 536-8523, Japan
| | - Shirou Fukuhara
- The First Department of Internal Medicine, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
| | - Chiyoko Inagaki
- Department of Pharmacology, Kansai Medical University, 10-15, Fumizono-Cho, Moriguchi, Osaka 570-8506, Japan
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Carlos MA, Nwagwu C, Ao M, Venkatasubramanian J, Boonkaewwan C, Prasad R, Chowdhury SAK, Vidyasagar D, Rao MC. Epidermal growth factor stimulates chloride transport in primary cultures of weanling and adult rabbit colonocytes. J Pediatr Gastroenterol Nutr 2007; 44:300-11. [PMID: 17325549 DOI: 10.1097/mpg.0b013e31802fca72] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVES We have shown that Ca2+-dependent regulation of Cl- secretion in the mammalian colon exhibits age dependence. Because epidermal growth factor (EGF) has a well-established role in growth and can increase intracellular calcium [Ca2+]i, it is conceivable that its developmental influence may extend to the regulation of intestinal ion transport. In this study, we examined the role of EGF in the regulation of Cl- transport in the developing rabbit distal colon. MATERIALS AND METHODS Because serum contains growth factors, which could have confounded our studies, we first established an optimal milieu for testing EGF in primary cultures of adult rabbit distal colonocytes by culturing them for 24 h in media containing 0%, 1%, 5%, and 20% serum. Chloride transport (millimoles per second) and [Ca2+]i were measured with use of the fluorescent indicator N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE) and Fura-2AM, respectively. RESULTS Serum depletion had no effect on cell number, DNA content, or basal Cl- transport, but it significantly affected cell viability. In media with 0%, 1%, or 20% serum, bethanechol, 8BrcAMP, taurodeoxycholate, and EGF stimulated Cl- transport to a similar extent. EGF maximally stimulated Cl- transport at 16.3 nmol/L and 20 minutes. Bethanechol, but not EGF, increased [Ca2+]i. EGF did not alter bethanechol-stimulated Cl- transport or [Ca2+]i. EGF acts via an EGF-receptor and mitogen activated protein kinase (MAPK) signaling pathway, since stimulation of Cl- transport was abolished by genistein, AG1478, and PD98059. Weanling and adult colonocytes, cultured in 1% serum, showed similar basal and EGF-stimulated Cl- transport. CONCLUSIONS EGF stimulates rabbit colonic Cl- transport via a Ca2+-independent, tyrosine kinase- and MAPK-dependent pathway, and its effects are not age dependent.
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Affiliation(s)
- Maria A Carlos
- Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
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Jiang X, Sinnett-Smith J, Rozengurt E. Differential FAK phosphorylation at Ser-910, Ser-843 and Tyr-397 induced by angiotensin II, LPA and EGF in intestinal epithelial cells. Cell Signal 2006; 19:1000-10. [PMID: 17240116 PMCID: PMC1868572 DOI: 10.1016/j.cellsig.2006.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 11/13/2006] [Accepted: 11/16/2006] [Indexed: 12/20/2022]
Abstract
A rapid increase in the tyrosine phosphorylation of the non-receptor tyrosine kinase FAK is a prominent early event in fibroblasts stimulated by a variety of signaling molecules. However, a variety of epithelial cells, including intestinal epithelial cells, show a high basal level of tyrosine phosphorylated FAK that is only slightly further increased by addition of G protein-coupled receptor (GPCR) agonists or growth factors. In this study, we determined whether these stimuli could elicit FAK phosphorylation at serine residues, including Ser-910 and Ser-843. Our results show that multiple agonists including angiotensin II (ANGII), lysophosphatidic acid (LPA), phorbol esters and EGF induced a striking stimulation of FAK phosphorylation at Ser-910 in rat intestinal epithelial IEC-18 cells via an ERK-dependent pathway. In striking contrast, none of these stimuli promoted a significant further increase in FAK phosphorylation at Tyr-397 in these cells. These results were extended using cultures of polarized human colonic epithelial T84 cells. We found that either carbachol or EGF promoted a striking ERK-dependent phosphorylation of FAK at Ser-910, but these agonists caused only slight stimulation of FAK at Tyr-397 in T84 cells. In addition, we demonstrated that GPCR agonists also induced a dramatic increase of FAK phosphorylation at Ser-843 in either IEC-18 or T84 cells. Our results indicate that Ser-910 and Ser-843, rather than Tyr-397, are prominent sites differentially phosphorylated in response to neurotransmitters, bioactive lipids, tumor promoters and growth factors in intestinal epithelial cells.
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Affiliation(s)
- Xiaohua Jiang
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095-178622, USA
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Eglen RM. Muscarinic receptor subtypes in neuronal and non-neuronal cholinergic function. AUTONOMIC & AUTACOID PHARMACOLOGY 2006; 26:219-33. [PMID: 16879488 DOI: 10.1111/j.1474-8673.2006.00368.x] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1 Muscarinic M1-M5 receptors mediate the metabotropic actions of acetylcholine in the nervous system. A growing body of data indicate they also mediate autocrine functions of the molecule. The availability of novel and selective muscarinic agonists and antagonists, as well as in vivo gene disruption techniques, has clarified the roles of muscarinic receptors in mediating both functions of acetylcholine. 2 Selective M1 agonists or mixed M1 agonists/M2 antagonists may provide an approach to the treatment of cognitive disorders, while M3 antagonism, or mixed M2/M3 antagonists, are approved for the treatment of contractility disorders including overactive bladder and chronic obstructive pulmonary disease. Preclinical data suggest that selective agonism of the M4 receptor will provide novel anti-nociceptive agents, while therapeutics-based upon agonism or antagonism of the muscarinic M5 receptor have yet to be reported. 3 The autocrine functions of muscarinic receptors broadly fall into two areas - control of cell growth or proliferation and mediation of the release of chemical mediators from epithelial cells, ultimately causing muscle relaxation. The former particularly are involved in embryological development, oncogenesis, keratinocyte function and immune responsiveness. The latter regulate contractility of smooth muscle in the vasculature, airways and urinary bladder. 4 Most attention has focused on muscarinic M1 or M3 receptors which mediate lymphocyte immunoresponsiveness, cell migration and release of smooth muscle relaxant factors. Muscarinic M4 receptors are implicated in the regulation of keratinocyte adhesion and M2 receptors in stem cell proliferation and development. Little data are available concerning the M5 receptor, partly due to the difficulties in defining the subtype pharmacologically. 5 The autocrine functions of acetylcholine, like those in the nervous system, involve activation of several muscarinic receptor subtypes. Consequently, the role of these subtypes in autocrine, as well neuronal cholinergic systems, significantly expands their importance in physiology and pathophysiology.
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Affiliation(s)
- R M Eglen
- DiscoveRx Corp, 42501, Albrae St., Suite 100, Fremont, CA 94538, USA
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