| 1. |
- Babbin, Brian A., et al.
(författare)
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Annexin A1 regulates intestinal mucosal injury, inflammation, and repair
- 2008
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Ingår i: Journal of Immunology. - Bethesda, United States : American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 181:7, s. 5035-5044
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Tidskriftsartikel (refereegranskat)abstract
- During mucosal inflammation, a complex array of proinflammatory and protective mechanisms regulates inflammation and severity of injury. Secretion of anti-inflammatory mediators is a mechanism that is critical in controlling inflammatory responses and promoting epithelial restitution and barrier recovery. AnxA1 is a potent anti-inflammatory protein that has been implicated to play a critical immune regulatory role in models of inflammation. Although AnxA1 has been shown to be secreted in intestinal mucosal tissues during inflammation, its potential role in modulating the injury/inflammatory response is not understood. In this study, we demonstrate that AnxA1-deficient animals exhibit increased susceptibility to dextran sulfate sodium (DSS)-induced colitis with greater clinical morbidity and histopathologic mucosal injury. Furthermore, impaired recovery following withdrawal of DSS administration was observed in AnxA1 (-/-) animals compared with wild-type (WT) control mice that was independent of inflammatory cell infiltration. Since AnxA1 exerts its anti-inflammatory properties through stimulation of ALX/FPRL-1, we explored the role of this receptor-ligand interaction in regulating DSS-induced colitis. Interestingly, treatment with an ALX/FPRL-1 agonist, 15-epi-lipoxin A4 reversed the enhanced sensitivity of AnxA1 (-/-) mice to DSS colitis. In contrast, 15-epi-lipoxin A4 did not significantly improve the severity of disease in WT animals. Additionally, differential expression of ALX/FPLR-1 in control and DSS-treated WT and AnxA1-deficient animals suggested a potential role for AnxA1 in regulating ALX/FPRL-1 expression under pathophysiological conditions. Together, these results support a role of endogenous AnxA1 in the protective and reparative properties of the intestinal mucosal epithelium.
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| 2. |
- Babbin, Brian A., et al.
(författare)
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Non-muscle myosin IIA differentially regulates intestinal epithelial cell restitution and matrix invasion
- 2009
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Ingår i: American Journal of Pathology. - : Elsevier. - 0002-9440 .- 1525-2191. ; 174:2, s. 436-448
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Tidskriftsartikel (refereegranskat)abstract
- Epithelial cell motility is critical for self-rejuvenation of normal intestinal mucosa, wound repair, and cancer metastasis. This process is regulated by the reorganization of the F-actin cytoskeleton, which is driven by a myosin II motor. However, the role of myosin II in regulating epithelial cell migration remains poorly understood. This study addressed the role of non-muscle myosin (NM) IIA in two different modes of epithelial cell migration: two-dimensional (2-D) migration that occurs during wound closure and three-dimensional (3-D) migration through a Matrigel matrix that occurs during cancer metastasis. Pharmacological inhibition or siRNA-mediated knockdown of NM IIA in SK-CO15 human colonic epithelial cells resulted in decreased 2-D migration and increased 3-D invasion. The attenuated 2-D migration was associated with increased cell adhesiveness to collagen and laminin and enhanced expression of beta1-integrin and paxillin. On the 2-D surface, NM IIA-deficient SK-CO15 cells failed to assemble focal adhesions and F-actin stress fibers. In contrast, the enhanced invasion of NM IIA-depleted cells was dependent on Raf-ERK1/2 signaling pathway activation, enhanced calpain activity, and increased calpain-2 expression. Our findings suggest that NM IIA promotes 2-D epithelial cell migration but antagonizes 3-D invasion. These observations indicate multiple functions for NM IIA, which, along with the regulation of the F-actin cytoskeleton and cell-matrix adhesions, involve previously unrecognized control of intracellular signaling and protein expression.
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| 3. |
- Autio, Anu, et al.
(författare)
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SIRPα - CD47 axis regulates dendritic cell-T cell interactions and TCR activation during T cell priming in spleen
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:4 April
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Tidskriftsartikel (refereegranskat)abstract
- The SIRPα-CD47 axis plays an important role in T cell recruitment to sites of immune reaction and inflammation but its role in T cell antigen priming is incompletely understood. Employing OTII TCR transgenic mice bred to Cd47-/- (Cd47KO) or SKI mice, a knock-in transgenic animal expressing non-signaling cytoplasmic-truncated SIRPα, we investigated how the SIRPα-CD47 axis contributes to antigen priming. Here we show that adoptive transfer of Cd47KO or SKI Ova-specific CD4+ T cells (OTII) into Cd47KO and SKI recipients, followed by Ova immunization, elicited reduced T cell division and proliferation indices, increased apoptosis, and reduced expansion compared to transfer into WT mice. We confirmed prior reports that splenic T cell zone, CD4+ conventional dendritic cells (cDCs) and CD4+ T cell numbers were reduced in Cd47KO and SKI mice. We report that in vitro derived DCs from Cd47KO and SKI mice exhibited impaired migration in vivo and exhibited reduced CD11c+ DC proximity to OTII T cells in T cell zones after Ag immunization, which correlates with reduced TCR activation in transferred OTII T cells. These findings suggest that reduced numbers of CD4+ cDCs and their impaired migration contributes to reduced T cell-DC proximity in splenic T cell zone and reduced T cell TCR activation, cell division and proliferation, and indirectly increased T cell apoptosis.
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| 4. |
- Baniulis, Danas, et al.
(författare)
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Monoclonal antibody CL5 recognizes the amino terminal domain of human phagocyte flavocytochrome b558 large subunit, gp91phox
- 2005
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Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 74:4, s. 337-347
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Tidskriftsartikel (refereegranskat)abstract
- Human phagocyte flavocytochrome b558 (Cytb) is a heterodimeric integral membrane protein that serves as the electron transferase of the β-nicotinamide adenine dinucleotidephosphate, reduced (NADPH)-oxidase, an enzyme complex important in the host defense function of phagocytic cells. In this study, we report the characterization of monoclonal antibody (mAb) CL5 that is specific for the large subunit, gp91phox, of the oxidase protein. This antibody recognizes gp91phox by immunoblot analysis of membrane extracts and samples of the immunopurified gp91phox/p22 phox heterodimer, prepared on anti-p22phox affinity matrices. Phage display analysis confirmed this specificity, indicating that the CL5 epitope contains the region 135-DPYSVALSELGDR of gp91phox. The antibody was used to probe for the presence of gp91phox in membrane preparations from neutrophils of patients with nine genetically distinct forms of X-linked chronic granulomatous disease (CGD). The causative mutations included missense errors as well as nonsense errors that result in premature termination of gp91phox synthesis. Analysis of the CGD samples by immunoblotting indicated that CL5 recognizes only the full-length wild-type and two missense mutations, consistent with the absence of stable short gp91 phox peptide expression in CGD neutrophils. Interestingly, CL5 was also shown to be cross-reactive with cytosolic and membrane-bound gelsolin, identified by purification, mass spectrometry and immunoblot analysis. CL5 probably cross-reacts with the sequence 771-DPLDRAMAEL in the C-terminus of gelsolin. We conclude that mAb CL5 is a useful probe for detection of full length and possibly truncated N-terminal fragments of gp91phox from membranes of Cytb-producing cells. © Blackwell Munksgaard 2005.
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| 5. |
- Capaldo, Christopher T., et al.
(författare)
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Tight function zonula occludens-3 regulates cyclin D1-dependent cell proliferation
- 2011
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Ingår i: Molecular Biology of the Cell. - Bethesda, United States : American Society for Cell Biology. - 1059-1524 .- 1939-4586. ; 22:10, s. 1677-1685
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Tidskriftsartikel (refereegranskat)abstract
- Coordinated regulation of cell proliferation is vital for epithelial tissue homeostasis, and uncontrolled proliferation is a hallmark of carcinogenesis. A growing body of evidence indicates that epithelial tight junctions (TJs) play a role in these processes, although the mechanisms involved are poorly understood. In this study, we identify and characterize a novel plasma membrane pool of cyclin D1 with cell-cycle regulatory functions. We have determined that the zonula occludens (ZO) family of TJ plaque proteins sequesters cyclin D1 at TJs during mitosis, through an evolutionarily conserved class II PSD-95, Dlg, and ZO-1 (PDZ)-binding motif within cyclin D1. Disruption of the cyclin D1/ZO complex through mutagenesis or siRNA-mediated suppression of ZO-3 resulted in increased cyclin D1 proteolysis and G(0)/G(1) cell-cycle retention. This study highlights an important new role for ZO family TJ proteins in regulating epithelial cell proliferation through stabilization of cyclin D1 during mitosis.
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| 6. |
- Garcia-Hernandez, Vicky, et al.
(författare)
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Systematic Scoring Analysis for Intestinal Inflammation in a Murine Dextran Sodium Sulfate-Induced Colitis Model
- 2021
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Ingår i: Journal of Visualized Experiments. - : JOURNAL OF VISUALIZED EXPERIMENTS. - 1940-087X. ; :168
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Tidskriftsartikel (refereegranskat)abstract
- Murine colitis models are tools that are extensively employed in studies focused on understanding the pathobiology of inflammatory intestinal disorders. However, robust standards for objective and reproducible quantification of disease severity remain to be defined. Most colitis analysis methods rely on limited histological scoring of small segments of intestine, leading to partial or biased analyses. Here, we combine high-resolution image acquisition and longitudinal analysis of the entire colon to quantify intestinal injury and ulceration in the dextran sodium sulfate (DSS) induced model of murine colitis. This protocol allows for the generation of objective and reproducible results without extensive user training. Here, we provide comprehensive details on sample preparation and image analysis using examples of data from DSS induced colitis. This method can be easily adapted to other models of murine colitis that have significant inflammation associated with mucosal injury. We demonstrate that the fraction of inflamed/injured and eroded/ulcerated mucosa relative to the complete length of the colon closely parallels clinical findings such as weight loss amid DSS-induced disease progression. This histological protocol provides a reliable time and cost-effective aid to standardize analyses of disease activity in an unbiased way in DSS colitis experiments.
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| 7. |
- Khounlotham, Manirath, et al.
(författare)
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Compromised intestinal epithelial barrier induces adaptive immune compensation that protects from colitis
- 2012
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Ingår i: Immunity. - Cambridge, United States : Cell Press. - 1074-7613 .- 1097-4180. ; 37:3, s. 563-573
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Tidskriftsartikel (refereegranskat)abstract
- Mice lacking junctional adhesion molecule A (JAM-A, encoded by F11r) exhibit enhanced intestinal epithelial permeability, bacterial translocation, and elevated colonic lymphocyte numbers, yet do not develop colitis. To investigate the contribution of adaptive immune compensation in response to increased intestinal epithelial permeability, we examined the susceptibility of F11r(-/-)Rag1(-/-) mice to acute colitis. Although negligible contributions of adaptive immunity in F11r(+/+)Rag1(-/-) mice were observed, F11r(-/-)Rag1(-/-) mice exhibited increased microflora-dependent colitis. Elimination of T cell subsets and cytokine analyses revealed a protective role for TGF-beta-producing CD4(+) T cells in F11r(-/-) mice. Additionally, loss of JAM-A resulted in elevated mucosal and serum IgA that was dependent upon CD4(+) T cells and TGF-beta. Absence of IgA in F11r(+/+)Igha(-/-) mice did not affect disease, whereas F11r(-/-)Igha(-/-) mice displayed markedly increased susceptibility to acute injury-induced colitis. These data establish a role for adaptive immune-mediated protection from acute colitis under conditions of intestinal epithelial barrier compromise.
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| 8. |
- Koch, Stefan, et al.
(författare)
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Dkk-1 inhibits intestinal epithelial cell migration by attenuating directional polarization of leading edge cells
- 2009
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Ingår i: Molecular Biology of the Cell. - Bethesda, United States : American Society for Cell Biology. - 1059-1524 .- 1939-4586. ; 20:22, s. 4816-4825
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Tidskriftsartikel (refereegranskat)abstract
- Wnt signaling pathways regulate proliferation, motility, and survival in a variety of human cell types. Dickkopf-1 (Dkk-1) is a secreted Wnt antagonist that has been proposed to regulate tissue homeostasis in the intestine. In this report, we show that Dkk-1 is secreted by intestinal epithelial cells after wounding and that it inhibits cell migration by attenuating the directional orientation of migrating epithelial cells. Dkk-1 exposure induced mislocalized activation of Cdc42 in migrating cells, which coincided with a displacement of the polarity protein Par6 from the leading edge. Consequently, the relocation of the microtubule organizing center and the Golgi apparatus in the direction of migration was significantly and persistently inhibited in the presence of Dkk-1. Small interfering RNA-induced down-regulation of Dkk-1 confirmed that extracellular exposure to Dkk-1 was required for this effect. Together, these data demonstrate a novel role of Dkk-1 in the regulation of directional polarization of migrating intestinal epithelial cells, which contributes to the effect of Dkk-1 on wound closure in vivo.
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| 9. |
- Koch, Stefan
(författare)
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The Epithelial Barrier
- 2013
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Ingår i: Molecular Genetics of Inflammatory Bowel Disease. - New York, NY : Springer Science+Business Media B.V.. - 9781461482567 ; , s. 265-280
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Bokkapitel (refereegranskat)
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| 10. |
- Koch, Stefan, et al.
(författare)
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The Wnt antagonist Dkk1 regulates intestinal epithelial homeostasis and wound repair
- 2011
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Ingår i: Gastroenterology. - Maryland Heights, United States : W.B. Saunders Co.. - 0016-5085 .- 1528-0012. ; 141:1, s. 259-268
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Tidskriftsartikel (refereegranskat)abstract
- Background & AimsDkk1 is a secreted antagonist of the Wnt/β-catenin signaling pathway. It is induced by inflammatory cytokines during colitis and exacerbates tissue damage by promoting apoptosis of epithelial cells. However, little is known about the physiologic role of Dkk1 in normal intestinal homeostasis and during wound repair following mucosal injury. We investigated whether inhibition of Dkk1 affects the morphology and function of the adult intestine.MethodsWe used doubleridge mice (Dkk1d/d), which have reduced expression of Dkk1, and an inhibitory Dkk1 antibody to modulate Wnt/β-catenin signaling in the intestine. Intestinal inflammation was induced with dextran sulfate sodium (DSS), followed by a recovery period in which mice were given regular drinking water. Animals were killed before, during, or after DSS administration; epithelial homeostasis and the activity of major signaling pathways were investigated by morphometric analysis, bromo-2′-deoxyuridine incorporation, and immunostaining.ResultsReduced expression of Dkk1 increased proliferation of epithelial cells and lengthened crypts in the large intestine, which was associated with increased transcriptional activity of β-catenin. Crypt extension was particularly striking when Dkk1 was inhibited during acute colitis. Dkk1d/dmice recovered significantly faster from intestinal inflammation but exhibited crypt architectural irregularities and epithelial hyperproliferation compared with wild-type mice. Survival signaling pathways were concurrently up-regulated in Dkk1d/d mice, including the AKT/β-catenin, ERK/Elk-1, and c-Jun pathways.ConclusionsDkk1, an antagonist of Wnt/β-catenin signaling, regulates intestinal epithelial homeostasis under physiologic conditions and during inflammation. Depletion of Dkk1 induces a strong proliferative response that promotes wound repair after colitis.
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| 11. |
- Nava, Porfirio, et al.
(författare)
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IFN gamma-induced suppression of beta-catenin signaling : evidence for roles of Akt and 14.3.3 zeta
- 2014
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Ingår i: Molecular Biology of the Cell. - Bethesda, United States : American Society for Cell Biology. - 1059-1524 .- 1939-4586. ; 25:19, s. 2894-2904
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Tidskriftsartikel (refereegranskat)abstract
- The proinflammatory cytokine interferon gamma (IFNgamma ) influences intestinal epithelial cell (IEC) homeostasis in a biphasic manner by acutely stimulating proliferation that is followed by sustained inhibition of proliferation despite continued mucosal injury. beta-Catenin activation has been classically associated with increased IEC proliferation. However, we observed that IFNgamma inhibits IEC proliferation despite sustained activation of Akt/beta-catenin signaling. Here we show that inhibition of Akt/beta-catenin-mediated cell proliferation by IFNgamma is associated with the formation of a protein complex containing phosphorylated beta-catenin 552 (pbeta-cat552) and 14.3.3zeta. Akt1 served as a bimodal switch that promotes or inhibits beta-catenin transactivation in response to IFNgamma stimulation. IFNgamma initially promotes beta-catenin transactivation through Akt-dependent C-terminal phosphorylation of beta-catenin to promote its association with 14.3.3zeta. Augmented beta-catenin transactivation leads to increased Akt1 protein levels, and active Akt1 accumulates in the nucleus, where it phosphorylates 14.3.3zeta to translocate 14.3.3zeta/beta-catenin from the nucleus, thereby inhibiting beta-catenin transactivation and IEC proliferation. These results outline a dual function of Akt1 that suppresses IEC proliferation during intestinal inflammation.
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| 12. |
- Nava, Porfirio, et al.
(författare)
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Interferon-gamma regulates intestinal epithelial homeostasis through converging beta-catenin signaling pathways
- 2010
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Ingår i: Immunity. - Cambridge, United States : Cell Press. - 1074-7613 .- 1097-4180. ; 32:3, s. 392-402
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Tidskriftsartikel (refereegranskat)abstract
- Inflammatory cytokines have been proposed to regulate epithelial homeostasis during intestinal inflammation. We report here that interferon-gamma (IFN-gamma) regulates the crucial homeostatic functions of cell proliferation and apoptosis through serine-threonine protein kinase AKT-beta-catenin and Wingless-Int (Wnt)-beta-catenin signaling pathways. Short-term exposure of intestinal epithelial cells to IFN-gamma resulted in activation of beta-catenin through AKT, followed by induction of the secreted Wnt inhibitor Dkk1. Consequently, we observed an increase in Dkk1-mediated apoptosis upon extended IFN-gamma treatment and reduced proliferation through depletion of the Wnt coreceptor LRP6. These effects were enhanced by tumor necrosis factor-alpha (TNF-alpha), suggesting synergism between the two cytokines. Consistent with these results, colitis in vivo was associated with decreased beta-catenin-T cell factor (TCF) signaling, loss of plasma membrane-associated LRP6, and reduced epithelial cell proliferation. Proliferation was partially restored in IFN-gamma-deficient mice. Thus, we propose that IFN-gamma regulates intestinal epithelial homeostasis by sequential regulation of converging beta-catenin signaling pathways.
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| 13. |
- Nava, Porfirio, et al.
(författare)
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JAM-A regulates epithelial proliferation through Akt/beta-catenin signalling
- 2011
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Ingår i: EMBO Reports. - : Wiley-Blackwell Publishing Inc.. - 1469-221X .- 1469-3178. ; 12:4, s. 314-20
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Tidskriftsartikel (refereegranskat)abstract
- Expression of the tight junction protein junctional adhesion molecule-A (JAM-A) has been linked to proliferation and tumour progression. However, a direct role for JAM-A in regulating proliferative processes has not been shown. By using complementary in vivo and in vitro approaches, we demonstrate that JAM-A restricts intestinal epithelial cell (IEC) proliferation in a dimerization-dependent manner, by inhibiting Akt-dependent beta-catenin activation. Furthermore, IECs from transgenic JAM-A(-/-)/beta-catenin/T-cell factor reporter mice showed enhanced beta-catenin-dependent transcription. Finally, inhibition of Akt reversed colonic crypt hyperproliferation in JAM-A-deficient mice. These data establish a new link between JAM-A and IEC homeostasis.
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| 14. |
- Samarin, Stanislav N., et al.
(författare)
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Coronin 1C negatively regulates cell-matrix adhesion and motility of intestinal epithelial cells
- 2010
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier. - 0006-291X .- 1090-2104. ; 391:1, s. 394-400
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Tidskriftsartikel (refereegranskat)abstract
- Coronins, WD-repeat actin-binding proteins, are known to regulate cell motility by coordinating actin filament turnover in lamellipodia of migrating cell. Here we report a novel mechanism of Coronin 1C-mediated cell motility that involves regulation of cell-matrix adhesion. RNAi silencing of Coronin 1C in intestinal epithelial cells enhanced cell migration and modulated lamellipodia dynamics by increasing the persistence of lamellipodial protrusion. Coronin 1C-depleted cells showed increased cell-matrix adhesions and enhanced cell spreading compared to control cells, while over-expression of Coronin 1C antagonized cell adhesion and spreading. Enhanced cell-matrix adhesion of coronin-deficient cells correlated with hyperphosphorylation of focal adhesion kinase (FAK) and paxillin, and an increase in number of focal adhesions and their redistribution at the cell periphery. siRNA depletion of FAK in coronin-deficient cells rescued the effects of Coronin 1C depletion on motility, cell-matrix adhesion, and spreading. Thus, our findings provide the first evidence that Coronin 1C negatively regulates epithelial cell migration via FAK-mediated inhibition of cell-matrix adhesion.
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