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Valanti EK, Dalakoura-Karagkouni K, Fotakis P, Vafiadaki E, Mantzoros CS, Chroni A, Zannis V, Kardassis D, Sanoudou D. Reconstituted HDL-apoE3 promotes endothelial cell migration through ID1 and its downstream kinases ERK1/2, AKT and p38 MAPK. Metabolism 2022; 127:154954. [PMID: 34875308 DOI: 10.1016/j.metabol.2021.154954] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/15/2021] [Accepted: 11/30/2021] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Atherosclerotic Coronary Artery Disease (ASCAD) is the leading cause of mortality worldwide. Novel therapeutic approaches aiming to improve the atheroprotective functions of High Density Lipoprotein (HDL) include the use of reconstituted HDL forms containing human apolipoprotein A-I (rHDL-apoA-I). Given the strong atheroprotective properties of apolipoprotein E3 (apoE3), rHDL-apoE3 may represent an attractive yet largely unexplored therapeutic agent. OBJECTIVE To evaluate the atheroprotective potential of rHDL-apoE3 starting with the unbiased assessment of global transcriptome effects and focusing on endothelial cell (EC) migration as a critical process in re-endothelialization and atherosclerosis prevention. The cellular, molecular and functional effects of rHDL-apoE3 on EC migration-associated pathways were assessed, as well as the potential translatability of these findings in vivo. METHODS Human Aortic ECs (HAEC) were treated with rHDL-apoE3 and total RNA was analyzed by whole genome microarrays. Expression and phosphorylation changes of key EC migration-associated molecules were validated by qRT-PCR and Western blot analysis in primary HAEC, Human Coronary Artery ECs (HCAEC) and the human EA.hy926 EC line. The capacity of rHDL-apoE3 to stimulate EC migration was assessed by wound healing and transwell migration assays. The contribution of MEK1/2, PI3K and the transcription factor ID1 in rHDL-apoE3-induced EC migration and activation of EC migration-related effectors was assessed using specific inhibitors (PD98059: MEK1/2, LY294002: PI3K) and siRNA-mediated gene silencing, respectively. The capacity of rHDL-apoE3 to improve vascular permeability and hypercholesterolemia in vivo was tested in a mouse model of hypercholesterolemia (apoE KO mice) using Evans Blue assays and lipid/lipoprotein analysis in the serum, respectively. RESULTS rHDL-apoE3 induced significant expression changes in 198 genes of HAEC mainly involved in re-endothelialization and atherosclerosis-associated functions. The most pronounced effect was observed for EC migration, with 42/198 genes being involved in the following EC migration-related pathways: 1) MEK/ERK, 2) PI3K/AKT/eNOS-MMP2/9, 3) RHO-GTPases, 4) integrin. rHDL-apoE3 induced changes in 24 representative transcripts of these pathways in HAEC, increasing the expression of their key proteins PIK3CG, EFNB2, ID1 and FLT1 in HCAEC and EA.hy926 cells. In addition, rHDL-apoE3 stimulated migration of HCAEC and EA.hy926 cells, and the migration was markedly attenuated in the presence of PD98059 or LY294002. rHDL-apoE3 also increased the phosphorylation of ERK1/2, AKT, eNOS and p38 MAPK in these cells, while PD98059 and LY294002 inhibited rHDL-apoE3-induced phosphorylation of ERK1/2, AKT and p38 MAPK, respectively. LY had no effect on rHDL-apoE3-mediated eNOS phosphorylation. ID1 siRNA markedly decreased EA.hy926 cell migration by inhibiting rHDL-apoE3-triggered ERK1/2 and AKT phosphorylation. Finally, administration of a single dose of rHDL-apoE3 in apoE KO mice markedly improved vascular permeability as demonstrated by the reduced concentration of Evans Blue dye in tissues such as the stomach, the tongue and the urinary bladder and ameliorated hypercholesterolemia. CONCLUSIONS rHDL-apoE3 significantly enhanced EC migration in vitro, predominantly via overexpression of ID1 and subsequent activation of MEK1/2 and PI3K, and their downstream targets ERK1/2, AKT and p38 MAPK, respectively, and improved vascular permeability in vivo. These novel insights into the rHDL-apoE3 functions suggest a potential clinical use to promote re-endothelialization and retard development of atherosclerosis.
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Affiliation(s)
- Eftaxia-Konstantina Valanti
- 4th Department of Internal Medicine, Clinical Genomics and Pharmacogenomics Unit, 'Attikon' Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece; Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Katerina Dalakoura-Karagkouni
- Laboratory of Biochemistry, University of Crete Medical School, Heraklion, Greece; Division of Gene Regulation and Genomics, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Greece
| | | | - Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | | | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Vassilis Zannis
- Molecular Genetics, Boston University Medical School, Boston, USA
| | - Dimitris Kardassis
- Laboratory of Biochemistry, University of Crete Medical School, Heraklion, Greece; Division of Gene Regulation and Genomics, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Greece
| | - Despina Sanoudou
- 4th Department of Internal Medicine, Clinical Genomics and Pharmacogenomics Unit, 'Attikon' Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece; Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece; Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
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Ungefroren H, Wellner UF, Keck T, Lehnert H, Marquardt JU. The Small GTPase RAC1B: A Potent Negative Regulator of-and Useful Tool to Study-TGFβ Signaling. Cancers (Basel) 2020; 12:E3475. [PMID: 33266416 PMCID: PMC7700615 DOI: 10.3390/cancers12113475] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023] Open
Abstract
RAC1 and its alternatively spliced isoform, RAC1B, are members of the Rho family of GTPases. Both isoforms are involved in the regulation of actin cytoskeleton remodeling, cell motility, cell proliferation, and epithelial-mesenchymal transition (EMT). Compared to RAC1, RAC1B exhibits a number of distinctive features with respect to tissue distribution, downstream signaling and a role in disease conditions like inflammation and cancer. The subcellular locations and interaction partners of RAC1 and RAC1B vary depending on their activation state, which makes RAC1 and RAC1B ideal candidates to establish cross-talk with cancer-associated signaling pathways-for instance, interactions with signaling by transforming growth factor β (TGFβ), a known tumor promoter. Although RAC1 has been found to promote TGFβ-driven tumor progression, recent observations in pancreatic carcinoma cells surprisingly revealed that RAC1B confers anti-oncogenic properties, i.e., through inhibiting TGFβ-induced EMT. Since then, an unexpected array of mechanisms through which RAC1B cross-talks with TGFβ signaling has been demonstrated. However, rather than being uniformly inhibitory, RAC1B interacts with TGFβ signaling in a way that results in the selective blockade of tumor-promoting pathways, while concomitantly allowing tumor-suppressive pathways to proceed. In this review article, we are going to discuss the specific interactions between RAC1B and TGFβ signaling, which occur at multiple levels and include various components such as ligands, receptors, cytosolic mediators, transcription factors, and extracellular inhibitors of TGFβ ligands.
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Affiliation(s)
- Hendrik Ungefroren
- First Department of Medicine, Campus Lübeck, University Hospital Schleswig-Holstein, D-23538 Lübeck, Germany;
- Clinic for General Surgery, Visceral, Thoracic, Transplantation and Pediatric Surgery, Campus Kiel, University Hospital Schleswig-Holstein, D-24105 Kiel, Germany
| | - Ulrich F. Wellner
- Clinic for Surgery, Campus Lübeck, University Hospital Schleswig-Holstein, D-23538 Lübeck, Germany; (U.F.W.); (T.K.)
| | - Tobias Keck
- Clinic for Surgery, Campus Lübeck, University Hospital Schleswig-Holstein, D-23538 Lübeck, Germany; (U.F.W.); (T.K.)
| | | | - Jens-Uwe Marquardt
- First Department of Medicine, Campus Lübeck, University Hospital Schleswig-Holstein, D-23538 Lübeck, Germany;
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Rac1 silencing, NSC23766 and EHT1864 reduce growth and actin organization of bladder smooth muscle cells. Life Sci 2020; 261:118468. [PMID: 32961232 DOI: 10.1016/j.lfs.2020.118468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/07/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022]
Abstract
AIMS RacGTPase-mediated proliferation and smooth muscle contraction in the lower urinary tract has been recently suggested and may offer putative targets for treamtment of lower urinary tract symptoms. However, RacGTPase function for proliferation of detrusor smooth muscle cells is unknown and the specificity of Rac inhibitors has been questioned. Here, we examined effects of Rac1 knockdown and of the Rac inhibitors NSC23766 and EHT1864 in human bladder smooth muscle cells (hBSMCs). MAIN METHODS Rac1 expression was silenced by shRNA expression. Effects of silencing and Rac inhibitors were assessed by CCK-8 assay, EdU staining, RT-PCR, colony formation assay, flow cytometry, and phalloidin staining. KEY FINDINGS Silencing of Rac1 expression reduced the viability (up to 83% compared to scramble shRNA) and proliferation (virtually completely in proliferation assay), increased apoptosis (124%) and the number of dead cells (51%), and caused breakdown of actin organization (56% reduction of polymerized actin compared to scramble shRNA). Effects on proliferation, viability, and actin organization were mimicked by NSC23766 and EHT1864, while both compounds showed divergent effects on cell death (32-fold increase of dead cells by EHT1864, but not NSC23766). Effects of NSC23766 and EHT1864 on viability of hBSMCs were not altered by Rac1 knockdown. SIGNIFICANCE Rac1 promotes proliferation, viability, and cytoskeletal organization, and suppresses apoptosis in bladder smooth muscle cells, which may be relevant in overactive bladder or diabetes-related bladder dysfunction. NSC23766 and EHT1864 mimick these effects, but may act Rac1-independently, by shared and divergent effects.
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Kim YC, Gonzalez-Nieves R, Cutler ML. Rsu1 contributes to cell adhesion and spreading in MCF10A cells via effects on P38 map kinase signaling. Cell Adh Migr 2014; 9:227-32. [PMID: 25482629 PMCID: PMC4594256 DOI: 10.4161/19336918.2014.972775] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The ILK, PINCH, Parvin (IPP) complex regulates adhesion and migration via binding of ILK to β1 integrin and α−parvin thus linking focal adhesions to actin cytoskeleton. ILK also binds the adaptor protein PINCH which connects signaling proteins including Rsu1 to the complex. A recent study of Rsu1 and PINCH1 in non-transformed MCF10A human mammary epithelial cells revealed that the siRNA-mediated depletion of either Rsu1 or PINCH1 decreased the number of focal adhesions (FAs) and altered the distribution and localization of FA proteins. This correlated with reduced adhesion, failure to spread or migrate in response to EGF and a loss of actin stress fibers and caveolae. The depletion of Rsu1 caused significant reduction in PINCH1 implying that Rsu1 may function in part by regulating levels of PINCH1. However, Rsu1, but not PINCH1, was required for EGF-induced activation of p38 Map kinase and ATF2 phosphorylation, suggesting a Rsu1 function independent from the IPP complex. Reconstitution of Rsu1-depleted cells with a Rsu1 mutant (N92D) that does not bind to PINCH1 failed to restore FAs or migration but did promote IPP-independent spreading and constitutive as well as EGF-induced p38 activation. In this commentary we discuss p38 activity in adhesion and how Rsu1 expression may be linked to Map kinase kinase (MKK) activation and detachment-induced stress kinase signaling.
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Affiliation(s)
- Yong-Chul Kim
- a Department of Pathology; F. Edward Hebert School of Medicine ; Uniformed Services University of the Health Sciences ; Bethesda , MD USA
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Brimacombe CL, Wilson GK, Hübscher SG, McKeating JA, Farquhar MJ. A role for CD81 and hepatitis C virus in hepatoma mobility. Viruses 2014; 6:1454-72. [PMID: 24662676 PMCID: PMC3970161 DOI: 10.3390/v6031454] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/27/2014] [Accepted: 03/05/2014] [Indexed: 12/21/2022] Open
Abstract
Tetraspanins are a family of small proteins that interact with themselves, host transmembrane and cytosolic proteins to form tetraspanin enriched microdomains (TEMs) that regulate important cellular functions. Several tetraspanin family members are linked to tumorigenesis. Hepatocellular carcinoma (HCC) is an increasing global health burden, in part due to the increasing prevalence of hepatitis C virus (HCV) associated HCC. The tetraspanin CD81 is an essential receptor for HCV, however, its role in hepatoma biology is uncertain. We demonstrate that antibody engagement of CD81 promotes hepatoma spread, which is limited by HCV infection, in an actin-dependent manner and identify an essential role for the C-terminal interaction with Ezrin-Radixin-Moesin (ERM) proteins in this process. We show enhanced hepatoma migration and invasion following expression of CD81 and a reduction in invasive potential upon CD81 silencing. In addition, we reveal poorly differentiated HCC express significantly higher levels of CD81 compared to adjacent non-tumor tissue. In summary, these data support a role for CD81 in regulating hepatoma mobility and propose CD81 as a tumour promoter.
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Affiliation(s)
- Claire L Brimacombe
- Viral Hepatitis Research Group, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
| | - Garrick K Wilson
- Viral Hepatitis Research Group, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
| | - Stefan G Hübscher
- Centre for Liver Research and NIHR Birmingham Liver Biomedical Research Unit, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
| | - Jane A McKeating
- Viral Hepatitis Research Group, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
| | - Michelle J Farquhar
- Viral Hepatitis Research Group, Institute for Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
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Yamazoe T, Shiraki N, Toyoda M, Kiyokawa N, Okita H, Miyagawa Y, Akutsu H, Umezawa A, Sasaki Y, Kume K, Kume S. A synthetic nanofibrillar matrix promotes in vitro hepatic differentiation of embryonic stem cells and induced pluripotent stem cells. J Cell Sci 2013; 126:5391-9. [PMID: 24101719 DOI: 10.1242/jcs.129767] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Embryonic stem (ES) cells recapitulate normal developmental processes and serve as an attractive source for routine access to a large number of cells for research and therapies. We previously reported that ES cells cultured on M15 cells, or a synthesized basement membrane (sBM) substratum, efficiently differentiated into an endodermal fate and subsequently adopted fates of various digestive organs, such as the pancreas and liver. Here, we established a novel hepatic differentiation procedure using the synthetic nanofiber (sNF) as a cell culture scaffold. We first compared endoderm induction and hepatic differentiation between murine ES cells grown on sNF and several other substrata. The functional assays for hepatocytes reveal that the ES cells grown on sNF were directed into hepatic differentiation. To clarify the mechanisms for the promotion of ES cell differentiation in the sNF system, we focused on the function of Rac1, which is a Rho family member protein known to regulate the actin cytoskeleton. We observed the activation of Rac1 in undifferentiated and differentiated ES cells cultured on sNF plates, but not in those cultured on normal plastic plates. We also show that inhibition of Rac1 blocked the potentiating effects of sNF on endoderm and hepatic differentiation throughout the whole differentiation stages. Taken together, our results suggest that morphological changes result in cellular differentiation controlled by Rac1 activation, and that motility is not only the consequence, but is also able to trigger differentiation. In conclusion, we believe that sNF is a promising material that might contribute to tissue engineering and drug delivery.
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Affiliation(s)
- Taiji Yamazoe
- Division of Stem Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Honjo 2-2-1, Kumamoto 860-0811, Japan
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Gonzalez-Nieves R, Desantis AI, Cutler ML. Rsu1 contributes to regulation of cell adhesion and spreading by PINCH1-dependent and - independent mechanisms. J Cell Commun Signal 2013; 7:279-93. [PMID: 23765260 PMCID: PMC3889256 DOI: 10.1007/s12079-013-0207-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 05/28/2013] [Indexed: 01/29/2023] Open
Abstract
Cell adhesion and migration are complex processes that require integrin activation, the formation and dissolution of focal adhesion (FAs), and linkage of actin cytoskeleton to the FAs. The IPP (ILK, PINCH, Parvin) complex regulates FA formation via binding of the adaptor protein ILK to β1 integrin, PINCH and parvin. The signaling protein Rsu1 is linked to the complex via binding PINCH1. The role of Rsu1 and PINCH1 in adhesion and migration was examined in non-transformed mammary epithelial cells. Confocal microscopy revealed that the depletion of either Rsu1 or PINCH1 by siRNA in MCF10A cells decreased the number of focal adhesions and altered the distribution and localization of β1 integrin, vinculin, talin and paxillin without affecting the levels of FA protein expression. This correlated with reduced adhesion, failure to spread or migrate in response to EGF and a loss of actin stress fibers and caveolae. In addition, constitutive phosphorylation of actin regulatory proteins occurred in the absence of PINCH1. The depletion of Rsu1 caused significant reduction in PINCH1 implying that Rsu1 may function by regulating levels of PINCH1. However, while both Rsu1- or PINCH1-depleted cells retained the ability to activate adhesion signaling in response to EGF stimulation, only Rsu1 was required for EGF-induced p38 Map Kinase phosphorylation and ATF2 activation, suggesting an Rsu1 function independent from the IPP complex. Reconstitution of Rsu1-depleted cells with an Rsu1 mutant that does not bind to PINCH1 failed to restore FAs or migration but did promote spreading and constitutive p38 activation. These data show that Rsu1-PINCH1 association with ILK and the IPP complex is required for regulation of adhesion and migration but that Rsu1 has a critical role in linking integrin-induced adhesion to activation of p38 Map kinase signaling and cell spreading. Moreover, it suggests that Rsu1 may regulate p38 signaling from the IPP complex affecting other functions including survival.
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Affiliation(s)
- Reyda Gonzalez-Nieves
- Department of Pathology, F. Edward Hebert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
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Maxeiner H, Abdallah Y, Kuhlmann CRW, Schlüter KD, Wenzel S. Effects of cerivastatin on adrenergic pathways, hypertrophic growth and TGFbeta expression in adult ventricular cardiomyocytes. Eur J Cell Biol 2012; 91:367-74. [DOI: 10.1016/j.ejcb.2011.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 10/28/2022] Open
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Carlin CM, Celnik DF, Pak O, Wadsworth R, Peacock AJ, Welsh DJ. Low-dose fluvastatin reverses the hypoxic pulmonary adventitial fibroblast phenotype in experimental pulmonary hypertension. Am J Respir Cell Mol Biol 2012; 47:140-8. [PMID: 22383583 DOI: 10.1165/rcmb.2011-0411oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Hypoxic pulmonary hypertension is a worldwide public health problem. Statins attenuate hypoxic pulmonary hypertension in animal models, but the mechanism of action and applicability of these results to human treatment are not established. In hypoxic models, pulmonary artery fibroblast proliferation contributes substantially to pulmonary vascular remodeling. We previously showed that acute hypoxic pulmonary adventitial fibroblast proliferation can be selectively inhibited by statins and p38 mitogen-activated protein (MAP) kinase inhibitors. Here we used complementary chronic hypoxic and acute hypoxic coculture models to obtain necessary preclinical information regarding the utility of fluvastatin in the treatment of chronic hypoxic pulmonary hypertension. The effects of fluvastatin, cholesterol pathway intermediates, and related inhibitors on hypoxic adventitial fibroblast proliferation, p38 MAP kinase phosphorylation, and pulmonary artery smooth muscle cell proliferation were determined, using complementary chronic hypoxic rat and acute hypoxic bovine cell models. Fluvastatin reversed the proliferative phenotypic switch in adventitial fibroblasts from chronic hypoxic animals. This effect was circulation-specific, and implicated a Rac1-p38 MAP kinase signaling pathway. Coculture and conditioned media experiments also implicated this statin-sensitive signaling pathway in the release of pulmonary artery smooth muscle cell mitogens by hypoxic pulmonary adventitial fibroblasts. Treprostinil, sildenafil, and bosentan exerted no effect on the hypoxic fibroblast phenotype. Phenotypic changes (increased proliferation and mitogen release) in pulmonary artery fibroblasts during chronic hypoxia are dependent on a Rac1-p38 MAP kinase signaling pathway. The inhibition of these phenotypic changes with fluvastatin may be therapeutically relevant in high-altitude residents and in patients with hypoxic lung disease.
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Clarkin CE, Allen S, Kuiper NJ, Wheeler BT, Wheeler-Jones CP, Pitsillides AA. Regulation of UDP-glucose dehydrogenase is sufficient to modulate hyaluronan production and release, control sulfated GAG synthesis, and promote chondrogenesis. J Cell Physiol 2011; 226:749-61. [PMID: 20717929 DOI: 10.1002/jcp.22393] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Glycosaminoglycans (GAGs) are critical for extracellular matrix (ECM) integrity in cartilage but mechanisms regulating their synthesis are not defined. UDP-glucose dehydrogenase (UGDH) catalyses UDP-glucose oxidation to UDP-glucuronic acid, an essential monosaccharide in many GAGs. Our previous studies in articular surface (AS) cells from embryonic joints have established pivotal roles for mitogen-activated protein kinases (MAPK) in synthesis of the unsulfated GAG, hyaluronan (HA). We investigated the functional significance of UGDH in GAG production and chondrogenesis, and determined roles for MEK-ERK and p38MAPK pathways in regulating UGDH expression and function. Inhibitors of MEK and p38MAPK reduced UGDH protein in AS cells. Treatment with TGF-β (archetypal growth factor) increased UGDH expression, sulfated (s)-GAG/HA release and pericellular matrix formation in a p38MAPK-dependent manner. Retroviral overexpression of UGDH augmented HA/sGAG release and pericellular matrix elaboration, which were blocked by inhibiting MEK but not p38MAPK. UGDH overexpression increased cartilage nodule size in bone marrow culture, promoted chondrogenesis in limb bud micromass culture and selectively suppressed medium HA levels and modified GAG sulfation, as assessed by FACE analysis. Our data provide evidence that: (i) TGF-β regulates UGDH expression via p38MAPK to modulate sGAG/HA secretion, (ii) MEK-ERK, but not p38MAPK facilitates UGDH-induced HA and sGAG release, and (iii) increased UGDH expression promotes chondrogenesis directly and differential modifies GAG levels and sulfation. These results indicate a more diverse role for UGDH in the support of selective GAG production than previously described. Factors regulating UGDH may provide novel candidates for restoring ECM integrity in degenerative cartilage diseases, such as osteoarthritis.Arthritis Research Campaign.
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Affiliation(s)
- Claire E Clarkin
- Department of Veterinary Basic Sciences, Royal Veterinary College, University of London, London, UK
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Zhang P, Wang H, Min X, Wang Y, Tang J, Cheng J, Li D, Chen X, Cheng F, Wang N, Yang H. Pim-3 is expressed in endothelial cells and promotes vascular tube formation. J Cell Physiol 2009; 220:82-90. [PMID: 19229879 DOI: 10.1002/jcp.21733] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pim-3 is a member of proto-oncogene Pim family that encodes serine/threonine kinases. Pim proteins regulate both apoptosis and cellular metabolism by phosphorylating their substrates. Here, we report for the first time that Pim-3 is highly expressed at mRNA and protein levels in endothelial cells (ECs). We found that Pim-3 is concentrated at the cellular lamellipodia and co-localized with focal adhesion kinase (FAK). Pim-3 was dispersed from lamellipodia when ECs were treated with cytochalasin D, an inhibitor of actin polymerization. In addition, small-interfering RNA (siRNA)-mediated gene knockdown of Pim-3 significantly impaired EC spreading, migration, and proliferation, leading to a reduction in tube-like structure formation in a Matrigel assay. These results provide the novel evidence that Pim-3 plays an essential role in EC spreading and migration, suggesting that Pim-3 may be an important molecular target for the development of small-molecule inhibitors of angiogenesis.
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Affiliation(s)
- Peng Zhang
- Institute of Cardiovascular Science, DongFeng Hospital, YunYang Medical College, Hubei, China.
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