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Dubey RK, Baruscotti I, Stiller R, Fingerle J, Gillespie DG, Mi Z, Leeners B, Imthurn B, Rosselli M, Jackson EK. Adenosine, Via A 2B Receptors, Inhibits Human (P-SMC) Progenitor Smooth Muscle Cell Growth. Hypertension 2019; 75:109-118. [PMID: 31786976 DOI: 10.1161/hypertensionaha.119.13698] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
c-Kit+ progenitor smooth muscle cells (P-SMCs) can develop into SMCs that contribute to injury-induced neointimal thickening. Here, we investigated whether adenosine reduces P-SMC migration and proliferation and whether this contributes to adenosine's inhibitory actions on neointima formation. In human P-SMCs, 2-chloroadenosine (stable adenosine analogue) and BAY60-6583 (A2B agonist) inhibited P-SMC proliferation and migration. Likewise, increasing endogenous adenosine by blocking adenosine metabolism with erythro-9-(2-hydroxy-3-nonyl) adenine (inhibits adenosine deaminase) and 5-iodotubercidin (inhibits adenosine kinase) attenuated P-SMC proliferation and migration. Neither N6-cyclopentyladenosine (A1 agonist), CGS21680 (A2A agonist), nor N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (A3 agonist) affected P-SMC proliferation or migration. 2-Chloroadenosine increased cyclic AMP, reduced Akt phosphorylation (activates cyclin D expression), and reduced levels of cyclin D1 (promotes cell-cycle progression). Moreover, 2-chloroadenosine inhibited expression of Skp2 (promotes proteolysis of p27Kip1) and upregulated levels of p27Kip1 (negative cell-cycle regulator). A2B receptor knockdown prevented the effects of 2-chloroadenosine on cyclic AMP production and P-SMC proliferation and migration. Likewise, inhibition of adenylyl cyclase and protein kinase A rescued P-SMCs from the inhibitory effects of 2-chloroadenosine. The inhibitory effects of adenosine were similar in male and female P-SMCs. In vivo, peri-arterial (rat carotid artery) 2-chloroadenosine (20 μmol/L for 7 days) reduced neointimal hyperplasia by 64.5% (P<0.05; intima/media ratio: control, 1.4±0.02; treated, 0.53±0.012) and reduced neointimal c-Kit+ cells. Adenosine inhibits P-SMC migration and proliferation via the A2B receptor/cyclic AMP/protein kinase A axis, which reduces cyclin D1 expression and activity via inhibiting Akt phosphorylation and Skp2 expression and upregulating p27kip1 levels. Adenosine attenuates neointima formation in part by inhibiting infiltration and proliferation of c-Kit+ P-SMCs.
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Affiliation(s)
- Raghvendra K Dubey
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.).,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.).,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (R.K.D., D.G.G., Z.M., E.K.J.)
| | - Isabella Baruscotti
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.)
| | - Ruth Stiller
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.)
| | - Juergen Fingerle
- NMI Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Reutlingen, Germany (J.F.)
| | - Delbert G Gillespie
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (R.K.D., D.G.G., Z.M., E.K.J.)
| | - Zaichuan Mi
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (R.K.D., D.G.G., Z.M., E.K.J.)
| | - Brigitte Leeners
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.)
| | - Bruno Imthurn
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.)
| | - Marinella Rosselli
- From the Department of Obstetrics and Gynecology, Clinic for Reproductive Endocrinology, University Hospital Zurich (R.K.D., I.B., R.S., B.L., B.I., M.R.)
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (R.K.D., D.G.G., Z.M., E.K.J.)
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Dubey RK, Fingerle J, Gillespie DG, Mi Z, Rosselli M, Imthurn B, Jackson EK. Adenosine Attenuates Human Coronary Artery Smooth Muscle Cell Proliferation by Inhibiting Multiple Signaling Pathways That Converge on Cyclin D. Hypertension 2015; 66:1207-19. [PMID: 26416848 PMCID: PMC4644125 DOI: 10.1161/hypertensionaha.115.05912] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/07/2015] [Indexed: 01/01/2023]
Abstract
The goal of this study was to determine whether and how adenosine affects the proliferation of human coronary artery smooth muscle cells (HCASMCs). In HCASMCs, 2-chloroadenosine (stable adenosine analogue), but not N(6)-cyclopentyladenosine, CGS21680, or N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide, inhibited HCASMC proliferation (A2B receptor profile). 2-Chloroadenosine increased cAMP, reduced phosphorylation (activation) of ERK and Akt (protein kinases known to increase cyclin D expression and activity, respectively), and reduced levels of cyclin D1 (cyclin that promotes cell-cycle progression in G1). Moreover, 2-chloroadenosine inhibited expression of S-phase kinase-associated protein-2 (Skp2; promotes proteolysis of p27(Kip1)) and upregulated levels of p27(Kip1) (cell-cycle regulator that impairs cyclin D function). 2-Chloroadenosine also inhibited signaling downstream of cyclin D, including hyperphosphorylation of retinoblastoma protein and expression of cyclin A (S phase cyclin). Knockdown of A2B receptors prevented the effects of 2-chloroadenosine on ERK1/2, Akt, Skp2, p27(Kip1), cyclin D1, cyclin A, and proliferation. Likewise, inhibition of adenylyl cyclase and protein kinase A abrogated 2-chloroadenosine's inhibitory effects on Skp2 and stimulatory effects on p27(Kip1) and rescued HCASMCs from 2-chloroadenosine-mediated inhibition. Knockdown of p27(Kip1) also reversed the inhibitory effects of 2-chloroadenosine on HCASMC proliferation. In vivo, peri-arterial (rat carotid artery) 2-chloroadenosine (20 μmol/L for 7 days) downregulated vascular expression of Skp2, upregulated vascular expression of p27(Kip1), and reduced neointima hyperplasia by 71% (P<0.05; neointimal thickness: control, 37 424±18 371 pixels; treated, 10 352±2824 pixels). In conclusion, the adenosine/A2B receptor/cAMP/protein kinase A axis inhibits HCASMC proliferation by blocking multiple signaling pathways (ERK1/2, Akt, and Skp2) that converge at cyclin D, a key G1 cyclin that controls cell-cycle progression.
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Affiliation(s)
- Raghvendra K Dubey
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.).
| | - Jürgen Fingerle
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
| | - Delbert G Gillespie
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
| | - Zaichuan Mi
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
| | - Marinella Rosselli
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
| | - Bruno Imthurn
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
| | - Edwin K Jackson
- From the Department of Reproductive Endocrinology, University Hospital Zurich, Switzerland (R.K.D., M.R., B.I.); Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Switzerland (R.K.D.); Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine (D.G.G., Z.M., E.K.J.); and Preclinical Pharma Research 68/209, F. Hoffmann-La-Roche, Basel, Switzerland (J.F.)
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Castagnino P, Kothapalli D, Hawthorne EA, Liu SL, Xu T, Rao S, Yung Y, Assoian RK. miR-221/222 compensates for Skp2-mediated p27 degradation and is a primary target of cell cycle regulation by prostacyclin and cAMP. PLoS One 2013; 8:e56140. [PMID: 23409140 PMCID: PMC3567044 DOI: 10.1371/journal.pone.0056140] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 01/07/2013] [Indexed: 01/08/2023] Open
Abstract
p27(kip1) (p27) is a cdk-inhibitory protein with an important role in the proliferation of many cell types. SCF(Skp2) is the best studied regulator of p27 levels, but Skp2-mediated p27 degradation is not essential in vivo or in vitro. The molecular pathway that compensates for loss of Skp2-mediated p27 degradation has remained elusive. Here, we combine vascular injury in the mouse with genome-wide profiling to search for regulators of p27 during cell cycling in vivo. This approach, confirmed by RT-qPCR and mechanistic analysis in primary cells, identified miR-221/222 as a compensatory regulator of p27. The expression of miR221/222 is sensitive to proteasome inhibition with MG132 suggesting a link between p27 regulation by miRs and the proteasome. We then examined the roles of miR-221/222 and Skp2 in cell cycle inhibition by prostacyclin (PGI(2)), a potent cell cycle inhibitor acting through p27. PGI(2) inhibited both Skp2 and miR221/222 expression, but epistasis, ectopic expression, and time course experiments showed that miR-221/222, rather than Skp2, was the primary target of PGI(2). PGI(2) activates Gs to increase cAMP, and increasing intracellular cAMP phenocopies the effect of PGI(2) on p27, miR-221/222, and mitogenesis. We conclude that miR-221/222 compensates for loss of Skp2-mediated p27 degradation during cell cycling, contributes to proteasome-dependent G1 phase regulation of p27, and accounts for the anti-mitogenic effect of cAMP during growth inhibition.
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Affiliation(s)
- Paola Castagnino
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Devashish Kothapalli
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Elizabeth A. Hawthorne
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Shu-Lin Liu
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tina Xu
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Shilpa Rao
- Molecular Profiling Facility, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Yuval Yung
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Richard K. Assoian
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Castagnino P, Kothapalli D, Hawthorne EA, Xu T, Assoian RK. Cell-type- and cell-cycle-specific anti-mitogenesis by cicaprost. Prostaglandins Other Lipid Mediat 2010; 93:20-4. [PMID: 20457271 DOI: 10.1016/j.prostaglandins.2010.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/19/2010] [Accepted: 04/27/2010] [Indexed: 12/27/2022]
Abstract
Stents eluting anti-proliferative drugs limit restenosis, but drugs commonly used to date are relatively non-specific cytostatic agents which inhibit proliferation of intimal endothelial cells as well as medial smooth muscle cells and may thereby contribute to the clinical complications associated with angioplasty. In an effort to identify a more specific anti-proliferative agent, we compared the effects of rapamycin to those of cicaprost, a mimetic of the naturally occurring anti-mitogen, PGI(2). Rapamycin and cicaprost were both strongly anti-mitogenic in vascular smooth muscle cells (VSMCs). But unlike rapamycin, cicaprost did not inhibit mitogenesis in aortic endothelial cells even when used at concentrations >10-fold higher than its ED(50) for VSMCs. Similarly, both rapamycin and cicaprost have been reported to regulate levels of the cdk inhibitor, p27(kip1). But rapamycin remained anti-mitogenic in p27(kip1)-null VSMCs whereas the anti-mitogenic effect of cicaprost was completely dependent on p27(kip1). We conclude that stable PGI(2) mimetics may be highly specific inhibitors of p27(kip1)-dependent VSMC proliferation after vascular injury.
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Affiliation(s)
- Paola Castagnino
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084, United States.
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Martin KA, Gleim S, Elderon L, Fetalvero K, Hwa J. The human prostacyclin receptor from structure function to disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 89:133-66. [PMID: 20374736 DOI: 10.1016/s1877-1173(09)89006-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thirty years have passed since Vane and colleagues first described a substance, prostanoid X, from microsomal fractions (later called prostacyclin) that relaxed rather than contracted mesenteric arteries. The critical role of prostacyclin in many pathophysiological conditions, such as atherothrombosis, has only recently become appreciated (through receptor knockout mice studies, selective cyclooxygenase-2 inhibition clinical trials, and the discovery of dysfunctional prostacyclin receptor genetic variants). Additionally, important roles in such diverse areas as pain and inflammation, and parturition are being uncovered. Prostacyclin-based therapies, currently used for pulmonary hypertension, are accordingly emerging as possible treatments for such diseases, fueling interests in structure function studies for the receptor and signal transduction pathways in native cells. The coming decade is likely to yield many further exciting advances.
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Affiliation(s)
- Kathleen A Martin
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Kothapalli D, Flowers J, Xu T, Puré E, Assoian RK. Differential activation of ERK and Rac mediates the proliferative and anti-proliferative effects of hyaluronan and CD44. J Biol Chem 2008; 283:31823-9. [PMID: 18806267 DOI: 10.1074/jbc.m802934200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hyaluronan, a widely distributed component of the extracellular matrix, exists in a high molecular weight (native) form and lower molecular weight form (HMW- and LMW-HA, respectively). These different forms of hyaluronan bind to CD44 but elicit distinct effects on cellular function. A striking example is the opposing effects of HMW- and LMW-HA on the proliferation of vascular smooth muscle cells; the binding of HMW-HA to CD44 inhibits cell cycle progression, whereas the binding of LMW-HA to CD44 stimulates cell cycle progression. We now report that cyclin D1 is the primary target of LMW-HA in human vascular smooth muscle cells, as it is for HMW-HA, and that the opposing cell cycle effects of these CD44 ligands result from differential regulation of signaling pathways to cyclin D1. HMW-HA binding to CD44 selectively inhibits the GTP loading of Rac and Rac-dependent signaling to the cyclin D1 gene, whereas LMW-HA binding to CD44 selectively stimulates ERK activation and ERK-dependent cyclin D1 gene expression. These data describe a novel mechanism of growth control in which a ligand-receptor system generates opposing effects on mitogenesis by differentially regulating signaling pathways to a common cell cycle target. They also emphasize how a seemingly subtle change in matrix composition can have a profound effect on cell proliferation.
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Affiliation(s)
- Devashish Kothapalli
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6084, USA
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Abstract
We describe a self-amplifying feedback loop that autoinduces Skp2 during G1 phase progression. This loop, which contains Skp2 itself, p27kip1 (p27), cyclin E–cyclin dependent kinase 2, and the retinoblastoma protein, is closed through a newly identified, conserved E2F site in the Skp2 promoter. Interference with the loop, by knockin of a Skp2-resistant p27 mutant (p27T187A), delays passage through the restriction point but does not interfere with S phase entry under continuous serum stimulation. Skp2 knock down inhibits S phase entry in nontransformed mouse embryonic fibroblasts but not in human papilloma virus–E7 expressing fibroblasts. We propose that the essential role for Skp2-dependent degradation of p27 is in the formation of an autoinduction loop that selectively controls the transition to mitogen-independence, and that Skp2-dependent proteolysis may be dispensable when pocket proteins are constitutively inactivated.
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Affiliation(s)
- Yuval Yung
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Bondesen BA, Jones KA, Glasgow WC, Pavlath GK. Inhibition of myoblast migration by prostacyclin is associated with enhanced cell fusion. FASEB J 2007; 21:3338-45. [PMID: 17488951 DOI: 10.1096/fj.06-7070com] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Satellite cells are stem cells that are critical for the formation and growth of skeletal muscle during myogenesis. To differentiate and fuse, proliferating satellite cells or myoblasts must migrate and establish stable cell-cell contacts. However, the factors that regulate myoblast migration and fusion are not understood completely. We have identified PGI2 as a novel regulator of myogenesis in vitro. PGI2 is a member of the family of prostaglandins (PG), autocrine/paracrine signaling molecules synthesized via the cyclooxygenase-1 and -2 pathways. Primary mouse muscle cells both secrete PGI2 and express the PGI2 receptor, IP, at various stages of myogenesis. Using genetic and pharmacological approaches, we show that PGI2 is a negative regulator of myoblast migration that also enhances cell fusion. Thus, PGI2 may act as a "brake" on migrating cells to facilitate cell-cell contact and fusion. Together, our results highlight the importance of the balance between positive and negative regulators in cell migration and myogenesis. This work may have implications for migration of other populations of adult stem cells and/or cells that undergo fusion.
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Affiliation(s)
- Brenda A Bondesen
- Emory University School of Medicine, Department of Pharmacology, Atlanta, GA 30322, USA
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Kothapalli D, Zhao L, Hawthorne EA, Cheng Y, Lee E, Puré E, Assoian RK. Hyaluronan and CD44 antagonize mitogen-dependent cyclin D1 expression in mesenchymal cells. ACTA ACUST UNITED AC 2007; 176:535-44. [PMID: 17296798 PMCID: PMC2063987 DOI: 10.1083/jcb.200611058] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
High molecular weight (HMW) hyaluronan (HA) is widely distributed in the extracellular matrix, but its biological activities remain incompletely understood. We previously reported that HMW-HA binding to CD44 antagonizes mitogen-induced S-phase entry in vascular smooth muscle cells (SMCs; Cuff, C.A., D. Kothapalli, I. Azonobi, S. Chun, Y. Zhang, R. Belkin, C. Yeh, A. Secreto, R.K. Assoian, D.J. Rader, and E. Puré. 2001. J. Clin. Invest. 108:1031–1040); we now characterize the underlying molecular mechanism and document its relevance in vivo. HMW-HA inhibits the mitogen-dependent induction of cyclin D1 and down-regulation of p27kip1 in vascular SMCs. p27kip1 messenger RNA levels were unaffected by HMW-HA, but the expression of Skp2, the rate-limiting component of the SCF complex that degrades p27kip1, was reduced. Rescue experiments identified cyclin D1 as the primary target of HMW-HA. Similar results were observed in fibroblasts, and these antimitogenic effects were not detected in CD44-null cells. Analysis of arteries from wild-type and CD44-null mice showed that the effects of HMW-HA/CD44 on cyclin D1 and Skp2 gene expression are detected in vivo and are associated with altered SMC proliferation after vascular injury.
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MESH Headings
- Animals
- Arteries/cytology
- Arteries/metabolism
- Cell Proliferation/drug effects
- Cells, Cultured
- Cyclin D
- Cyclin-Dependent Kinase Inhibitor p27/genetics
- Cyclin-Dependent Kinase Inhibitor p27/metabolism
- Cyclins/drug effects
- Cyclins/genetics
- Cyclins/metabolism
- Down-Regulation/drug effects
- Down-Regulation/genetics
- Fibroblasts/metabolism
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/physiology
- Humans
- Hyaluronan Receptors/genetics
- Hyaluronan Receptors/metabolism
- Hyaluronan Receptors/pharmacology
- Hyaluronic Acid/metabolism
- Hyaluronic Acid/pharmacology
- Mesoderm/cytology
- Mesoderm/drug effects
- Mesoderm/metabolism
- Mice
- Mice, Knockout
- Mitogens/metabolism
- Mitogens/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- S-Phase Kinase-Associated Proteins/genetics
- S-Phase Kinase-Associated Proteins/metabolism
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Affiliation(s)
- Devashish Kothapalli
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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10
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Villanueva J, Yung Y, Walker JL, Assoian RK. ERK activity and G1 phase progression: identifying dispensable versus essential activities and primary versus secondary targets. Mol Biol Cell 2007; 18:1457-63. [PMID: 17314399 PMCID: PMC1838994 DOI: 10.1091/mbc.e06-10-0908] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The ERK subfamily of MAP kinases is a critical regulator of S phase entry. ERK activity regulates the induction of cyclin D1, and a sustained ERK signal is thought to be required for this effect, at least in fibroblasts. We now show that early G1 phase ERK activity is dispensable for the induction of cyclin D1 and that the critical ERK signaling period is restricted to 3-6 h after mitogenic stimulation of quiescent fibroblasts. Similarly, early G1 phase ERK activity is dispensable for entry into S phase. Moreover, if cyclin D1 is expressed ectopically, ERK activity becomes dispensable throughout the G1 phase. In addition to its effect on cyclin D1, ERK activity is thought to contribute to the down-regulation of p27kip1. We found that this effect is restricted to late G1/S phase. Mechanistic analysis showed that the ERK effect on p27kip1 is mediated by Skp2 and is secondary to its effect on cyclin D1. Our results emphasize the importance of mid-G1 phase ERK activity and resolve primary versus secondary ERK targets within the G1 phase cyclin-dependent kinases.
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Affiliation(s)
- Jessie Villanueva
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084
| | - Yuval Yung
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084
| | - Janice L. Walker
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084
| | - Richard K. Assoian
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6084
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Fetalvero KM, Martin KA, Hwa J. Cardioprotective prostacyclin signaling in vascular smooth muscle. Prostaglandins Other Lipid Mediat 2007; 82:109-18. [PMID: 17164138 DOI: 10.1016/j.prostaglandins.2006.05.011] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 05/08/2006] [Accepted: 05/11/2006] [Indexed: 01/09/2023]
Abstract
Prostacyclin plays an important cardioprotective role, which has been increasingly appreciated in recent years in light of adverse effects of COX-2 inhibitors in clinical trials. This cardioprotection is thought to be mediated, in part, by prostacyclin inhibition of platelet aggregation. Multiple lines of evidence suggest that prostacyclin additionally protects from cardiovascular disease by pleiotropic effects on vascular smooth muscle. Genetic deletion of the prostacyclin receptor in mice revealed an important role for prostacyclin in preventing the development of atherosclerosis, intimal hyperplasia, and restenosis. In vitro studies have shown these effects may be due to prostacyclin inhibition of vascular smooth muscle cell proliferation and migration. Prostacyclin has also been shown to promote vascular smooth muscle cell differentiation at the level of gene expression through the Gs/cAMP/PKA pathway. Recently identified single nucleotide polymorphisms in the prostacyclin receptor that compromise receptor function suggest that some genetic variations may predispose individuals to increased cardiovascular disease. Herein, we review the literature on the cardioprotective effects of prostacyclin on vascular smooth muscle, and the underlying molecular signaling mechanisms. Understanding the role of prostacyclin and other eicosanoid mediators in the vasculature may lead to improved therapeutic and preventative options for cardiovascular disease.
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Affiliation(s)
- Kristina M Fetalvero
- Department of Pharmacology and Toxicology, 7650 Remsen, Dartmouth Medical School, Hanover, NH 03755, and Department of Surgery, Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States
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Walker JL, Castagnino P, Chung BM, Kazanietz MG, Assoian RK. Post-transcriptional destabilization of p21cip1 by protein kinase C in fibroblasts. J Biol Chem 2006; 281:38127-32. [PMID: 17043352 DOI: 10.1074/jbc.m609622200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
p21(cip1) inhibits S phase entry by binding to cyclin-cdk2 (cyclin-dependent kinase-2) complexes. The levels of p21(cip1) are rapidly induced after mitogenic stimulation of quiescent fibroblasts and then down-regulate as the cells reach late G(1) phase and activate cyclin E-cdk2. In this study, we have shown that pharmacological inhibition of protein kinase C (PKC), expression of dominant negative PKCdelta, or knockdown of PKCdelta with small interfering RNA elevates p21(cip1) protein levels in mouse embryo fibroblasts. This effect is selective, post-transcriptional, and proteasome-dependent but distinct from previously identified post-transcriptional control mechanisms involving cyclin D1 and Skp2. PKCdelta inhibition results in a reduced entry into S phase, and this effect is not detected in p21(cip1)-null cells. Thus, post-transcriptional destabilization of p21(cip1) appears to be a major mitogenic effect of PKCdelta in fibroblasts.
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Affiliation(s)
- Janice L Walker
- Department of Pharmacology, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, Philadelphia, PA 19104-6084, USA
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Fiaschi-Taesch N, Sicari BM, Ubriani K, Bigatel T, Takane KK, Cozar-Castellano I, Bisello A, Law B, Stewart AF. Cellular mechanism through which parathyroid hormone-related protein induces proliferation in arterial smooth muscle cells: definition of an arterial smooth muscle PTHrP/p27kip1 pathway. Circ Res 2006; 99:933-42. [PMID: 17023675 DOI: 10.1161/01.res.0000248184.21644.20] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) is present in vascular smooth muscle (VSM), is markedly upregulated in response to arterial injury, is essential for normal VSM proliferation, and also markedly accentuates neointima formation following rat carotid angioplasty. PTHrP contains a nuclear localization signal (NLS) through which it enters the nucleus and leads to marked increases in retinoblastoma protein (pRb) phosphorylation and cell cycle progression. Our goal was to define key cell cycle molecules upstream of pRb that mediate cell cycle acceleration induced by PTHrP. The cyclin D/cdk-4,-6 system and its upstream regulators, the inhibitory kinases (INKs), are not appreciably influenced by PTHrP. In striking contrast, cyclin E/cdk-2 kinase activity is markedly increased by PTHrP, and this is a result of a specific, marked, PTHrP-induced proteasomal degradation of p27(kip1). Adenoviral restoration of p27(kip1) fully reverses PTHrP-induced cell cycle progression, indicating that PTHrP mediates its cell cycle acceleration in VSM via p27(kip1). In confirmation, adenoviral delivery of PTHrP to murine primary vascular smooth muscle cells (VSMCs) significantly decreases p27(kip1) expression and accelerates cell cycle progression. p27(kip1) is well known to be a central cell cycle regulatory molecule involved in both normal and pathological VSM proliferation and is a target of widely used drug-eluting stents. The current observations define a novel "PTHrP/p27(kip1) pathway" in the arterial wall and suggest that this pathway is important in normal arterial biology and a potential target for therapeutic manipulation of the arterial response to injury.
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Cho CH, Seo M, Lee YI, Kim SY, Youn HD, Juhnn YS. Dibutyryl cAMP stimulates the proliferation of SH-SY5Y human neuroblastoma cells by up-regulating Skp2 protein. J Cancer Res Clin Oncol 2006; 133:135-44. [PMID: 17004068 DOI: 10.1007/s00432-006-0153-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 08/02/2006] [Indexed: 01/19/2023]
Abstract
PURPOSE We previously found that the proliferation of SH-SY5Y neuroblastoma cells is stimulated when cAMP is up-regulated by stable expression of stimulatory G protein. Therefore, this study was performed to investigate the mechanism whereby cAMP stimulates the proliferation of SH-SY5Y cells. METHODS To investigate the effect of cAMP on cellular proliferation, SH-SY5Y neuroblastoma cells were treated with dibutyryl cAMP (dbcAMP), and then cell growth, thymidine incorporation and cell cycle phase distribution were analyzed. The expression and the activity of the molecules that regulate cell cycle progression were monitored by Western blot, RT-PCR, and kinase activity assay. RESULTS Treatment with dbcAMP produced a biphasic effect on cellular proliferation; especially treatment with low concentration of dbcAMP (0.5 mM) showed a higher cellular proliferation rate and promoted G1/S transition in cell cycle. The dbcAMP (0.5 mM) treatment increased CDK2 activity, and it significantly decreased p27Kip1 expression with a decreased half-life of p27Kip1 protein. Moreover, dbcAMP (0.5 mM) increased the protein level and the stability of Skp2 with a concomitant decrease in its ubiquitination. CONCLUSIONS cAMP up-regulates Skp2 protein by reducing its degradation probably through decreasing the ubiquitination of Skp2, which might result in accelerated degradation of p27Kip1, increase in CDK2 activity, and stimulation of SH-SY5Y cell proliferation in sequence.
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Affiliation(s)
- Chin-Ho Cho
- Department of Biochemistry and Molecular Biology, Laboratory of Cellular Signaling, Cancer Research Institute, Seoul National University College of Medicine, 28 Yongon-dong, Jongno-gu, Seoul, 110-799, South Korea
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15
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Bryant P, Zheng Q, Pumiglia K. Focal adhesion kinase controls cellular levels of p27/Kip1 and p21/Cip1 through Skp2-dependent and -independent mechanisms. Mol Cell Biol 2006; 26:4201-13. [PMID: 16705171 PMCID: PMC1489078 DOI: 10.1128/mcb.01612-05] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Endothelial cell proliferation is a critical step in angiogenesis and requires a coordinated response to soluble growth factors and the extracellular matrix. As focal adhesion kinase (FAK) integrates signals from both adhesion events and growth factor stimulation, we investigated its role in endothelial cell proliferation. Expression of a dominant-negative FAK protein, FAK-related nonkinase (FRNK), impaired phosphorylation of FAK and blocked DNA synthesis in response to multiple angiogenic stimuli. These results coincided with elevated cyclin-dependent kinase inhibitors (CDKIs) p21/Cip and p27/Kip, as a consequence of impaired degradation. FRNK inhibited the expression of Skp2, an F-box protein that targets CDKIs, by inhibiting mitogen-induced mRNA. The FAK-regulated degradation of p27/Kip was Skp2 dependent, while levels of p21/Cip were regulated independent of Skp2. Skp2 is required for endothelial cell proliferation as a consequence of degrading p27. Finally, knockdown of both p21 and p27 in FRNK-expressing cells completely restored mitogen-induced endothelial cell proliferation. These data demonstrate a critical role for FAK in the regulation of CDKIs through two independent mechanisms: Skp2 dependent and Skp2 independent. They also provide important insights into the requirement of focal adhesion kinase for normal vascular development and reveal novel regulatory control points for angiogenesis.
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Affiliation(s)
- Patrick Bryant
- Center for Cell Biology and Cancer Research, Albany Medical College, 47 New Scotland Ave., Albany, NY 12208, USA
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16
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Wu YJ, Bond M, Sala-Newby GB, Newby AC. Altered S-phase kinase-associated protein-2 levels are a major mediator of cyclic nucleotide-induced inhibition of vascular smooth muscle cell proliferation. Circ Res 2006; 98:1141-50. [PMID: 16574903 DOI: 10.1161/01.res.0000219905.16312.28] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cyclic nucleotides inhibit vascular smooth muscle cell (VSMC) proliferation but the underlying molecular mechanisms are incompletely understood. We studied the role of S-phase kinase-associated protein-2 (Skp2), an F-box protein of SCFSkp2 ubiquitin ligase responsible for polyubiquitylation of and subsequent proteolysis of p27Kip1, a key step leading to cell cycle progression. Skp2 mRNA and protein were upregulated in mitogen-stimulated VSMCs and after balloon injury in rat carotid arteries, where the time course and location of Skp2 expression closely paralleled that of proliferating cell nuclear antigen. Skp2 small interference RNA (siRNA) reduced Skp2 expression, increased p27Kip1 levels, and inhibited VSMC proliferation in vitro. cAMP-elevating agents prominently inhibited VSMC proliferation and Skp2 expression through inhibiting Skp2 transcription as well as decreasing Skp2 protein stability. Consistent with this, activation of protein kinase A, a downstream target of cAMP, was shown to negatively regulate focal adhesion kinase (FAK) phosphorylation and Skp2 expression. Adenovirus-mediated Skp2 expression reversed cAMP-induced p27Kip1 upregulation and rescued cAMP-related S-phase entry inhibition up to 50%. 8-bromo-cGMP also moderately reduced Skp2 and cell proliferation when VSMCs were incubated with low serum concentration. Interestingly, we showed that 8-bromo-cGMP inhibited Skp2 expression also through activation of protein kinase A, not protein kinase G, which conversely enhanced FAKY397 phosphorylation and Skp2 expression. After balloon injury of rat carotid arteries, local forskolin treatment significantly reduced FAKY397 phosphorylation, Skp2 expression, VSMC proliferation, and subsequent neointimal thickening. These data demonstrate for the first time that Skp2 is an important factor in VSMC proliferation and its inhibition by cyclic nucleotides.
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MESH Headings
- Animals
- Blood
- Bucladesine/pharmacology
- Carotid Artery Injuries/enzymology
- Carotid Artery Injuries/pathology
- Catheterization
- Cell Proliferation/drug effects
- Cells, Cultured
- Cyclic GMP/analogs & derivatives
- Cyclic GMP/pharmacology
- Drug Stability
- Male
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/pathology
- Nucleotides, Cyclic/pharmacology
- Rats
- Rats, Sprague-Dawley
- S-Phase Kinase-Associated Proteins/chemistry
- S-Phase Kinase-Associated Proteins/genetics
- S-Phase Kinase-Associated Proteins/metabolism
- Transcription, Genetic/drug effects
- Tunica Intima/pathology
- Up-Regulation
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Affiliation(s)
- Yih-Jer Wu
- Bristol Heart Institute, University of Bristol, United Kingdom
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Kothapalli D, Flores-Stewart SA, Assoian RK. Antimitogenic effects of prostacyclin on the G1 phase cyclin-dependent kinases. Prostaglandins Other Lipid Mediat 2005; 78:3-13. [PMID: 16303599 DOI: 10.1016/j.prostaglandins.2005.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 04/01/2005] [Indexed: 12/12/2022]
Abstract
The prostanoid prostacyclin (PGI2) inhibits proliferation of cultured vascular SMCs by inhibiting cell cycle progression from G1 to S phase. Progression through G1 phase is regulated by the sequential activation of the G1 phase cyclin-dependent kinases (cdks). Recent studies have shown that PGI2-dependent activation of its receptor, IP, inhibits G1 phase progression by blocking the degradation of p27 and the activation of cyclin E-cdk2. High Density Lipoproteins (HDL) and its associated apolipoprotein, ApoE, also inhibit S phase entry of vascular SMCs, and the effects of HDL and ApoE are, at least in part, also mediated by the production of PGI2. The antimitogenic effects of hyaluronan may also be controlled by PGI2. This review summarizes the effects of PGI2 on the G1 phase cyclin-cdks and discusses the potential role of PGI2 as a common component of multiple extracellular signals that attenuate the proliferation of vascular SMCs.
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Affiliation(s)
- Devashish Kothapalli
- Department of Pharmacology, University of Pennsylvania School of Medicine, 3620 Hamilton Walk, 167 Johnson Pavilion, Philadelphia, PA 19104-6084, USA
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Nasrallah R, Hébert RL. Prostacyclin signaling in the kidney: implications for health and disease. Am J Physiol Renal Physiol 2005; 289:F235-46. [PMID: 16006589 DOI: 10.1152/ajprenal.00454.2004] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The balance between vasodilator and vasoconstrictor pathways is key to the maintenance of homeostasis and the outcome of disease. In the kidney, prostaglandins (PGs) uphold this balance and regulate renal function: hemodynamics, renin secretion, growth responses, tubular transport processes, and cell fate. With the advent of cyclooxygenase (COX)-2-selective inhibitors, targeted deletions in mice (COX knockouts, PG receptor knockouts), and the discovery of intracrine signaling options for PGs (peroxisome proliferator-activated receptors and perinuclear PGE2receptors: EP1,3,4), many advances have been made in the study of arachidonic acid metabolites. Although prostacyclin (PGI2) is a major product of the COX pathway, there is very little emphasis on its importance to the kidney. This review will discuss PGI2biology and its relevance to different aspects of renal disease (growth, fibrosis, apoptosis), highlighting the most significant research from the past decade of PGI2literature, what we have learned from other organ systems, while stressing the significance of cross talk between various PGI2signaling pathways and its implications for renal health and disease.
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Affiliation(s)
- Rania Nasrallah
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Canada
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