Published online before print October 16, 2008, doi: 10.1161/ATVBAHA.108.172247
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© 2009 American Heart Association, Inc.
Cell Biology/Signaling |
Formation of STAT5/PPAR
Transcriptional Complex Modulates Angiogenic Cell Bioavailability in Diabetes
From the Department of Internal Medicine (P.D., A.T., G.T., A.Z., A.R., B.U., L.P., M.F.B.) and the Molecular Biotechnology Center and Department Oncological Sciences (F.O., D.T.), University of Torino, Italy.
Correspondence to Maria Felice Brizzi, MD, Department of Internal Medicine, University of Torino, Corso Dogliotti 14, 10126, Torino, Italy. E-mail mariafelice.brizzi{at}unito.it
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Objective— Circulating angiogenic cells (CACs) expansion is a multistage process requiring sequential activation of transcriptional factors, including STAT5. STAT5, in concert with peroxisome proliferator-activated receptors (PPARs), seems to induce discrete biological responses in different tissues. In the present study we investigated the role of STAT5 and PPAR
in regulating CAC expansion in normal and diabetic settings.
Methods and Results— Normal and diabetic CACs were used. siRNA technology, EMSA, and chromatin immunoprecipitation (ChIP) assay as well as site-directed mutagenesis of the STAT5 response element in the PPAR promoter enabled us to demonstrate that STAT5 transcriptional activity controls PPAR expression. Moreover, FACS analysis, coimmunoprecipitation experiments, and ChIP assay revealed that a STAT5/PPAR transcriptional complex controls cyclin D1 expression and CAC progression into the cell-cycle. Conversely, PPAR agonists, by preventing the expression of STAT5 and the formation of the STAT5/PPAR heterodimeric complex failed to promote CAC expansion. Finally, we demonstrated that diabetic CAC functional capability can be recovered by molecules able to activate the STAT5/PPAR transcriptional complex.
Conclusions— Our data identify the STAT5/PPAR heterodimers as landmark of CAC expansion and provide evidences for a mechanism that partially rescues CAC bioavailability in diabetic setting.
We investigated the role of STAT5 and PPAR in regulating CAC expansion in normal and diabetic settings. We provide evidences that STAT5 controls PPAR expression and the formation of a STAT5/PPAR transcriptional complex, which is a permissive event for normal and diabetic CAC expansion.
Key Words: STAT5 • PPAR • diabetes • EPC • angiogenesis
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Vascular complications, such as atherosclerosis, are a primary cause of mortality associated with diabetes and obesity. Thus, vascular protection is critical to decrease mortality and improve public health.1 To accomplish this protection one member of the peroxisome proliferator-activated receptors (PPARs) has emerged.2 Mammalian PPARs include 3 subtypes (
, β/
, and ), which are characterized by unique functions such as ligand specificities and tissue distributions.3 PPARs are ligand-activated transcription factors that, by retinoid X receptors (RXRs) heterodimer formation and binding to specific DNA response elements (PPREs), modulate gene expression.4,5 PPAR is a key mediator in adipogenesis,6 lipid metabolism,7 and glucose homeostasis.8 Moreover, compelling evidence suggests that PPAR can influence target genes and processes that are of central relevance to endothelial biology.9 In addition, PPAR inhibits the expression of inflammatory genes and negatively interferes with proinflammatory transcription factor signaling pathways in inflammatory cells.10–12 Recently, it has been reported that treatment of diabetic patients with the PPAR ligands, possibly by modulating subclinical inflammatory activity or attenuating the detrimental effects of C reactive protein (CRP), increases the number and improves the functional capacity of endothelial progenitor cells (EPCs), thus providing evidence for PPAR-mediated vascular protection.13
See accompanying article on page 10
From the initial report,14 intense efforts have been focused on defining the role of circulating bone marrow–derived EPCs in the repair of damaged vascular endothelium and on translating this information into human clinical trials. To date, two types of EPCs have been described: true EPCs and circulating angiogenic cells (CACs).15 Expansion of CACs is a multistep process that requires the activation of signaling pathways that are still under investigation. We recently demonstrated that the inflammatory cytokine interleukin (IL)-3, by activating STAT5, promotes CAC expansion.16 STAT5 is a latent cytoplasmic transcription factor, ubiquitously expressed, that requires the JAK or the Src kinases to undergo activation.16–18 In addition, STAT5, in concert with PPARs, has been reported to induce discrete biological responses in different tissues.19–22
Herein we investigated the potential targets of STAT5 in regulating CAC expansion. In particular the relevance of the STAT5/PPAR cross-talk in regulating this event was evaluated both in normal and in diabetic CACs.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Reagents and Antibodies
Reagents and antibodies used are listed in the supplement materials (available online at http://atvb.ahajournals.org).
Patients and Controls
Blood was recovered from 5 type 2 diabetic patients, arrived in our patient clinic (sex, M/F 2/3; HbA1c, 6.4±0.6%; age-years, 50.0±5; creatinine, 1±1 mg/dL; no retinopathy, no hypertension: blood pressure <140/90 mm Hg; Chol/apoB, 1.3±0.1). None of them was under insulin and all were treated only with diet. Ten blood donors were used as controls (sex, M/F 5/5; HbA1c, 5±01.0%; age-years, 50.0±1; creatinine, 0.7±0.4 mg/dL, no retinopathy, no hypertension: blood pressure 
140/90 mm Hg, Chol/apoB, 1.6±0.1). The approval was obtained both from SIMT (Servizio Immunoematologia e Medicina Trasfusionale) and from the Institutional Review Board of S. Giovanni Battista Hospital, Turin, Italy. Informed consent was provided according to the Declaration of Helsinki. We also declare that for the present study, we had no direct contact with human subjects.
Cell Purification and Transfection
CACs, recovered from healthy subjects and diabetic patients, were isolated as described by Hill et al23 and cultured as described in the supplement materials. In selected experiments CACs were cultured in the presence of troglitazone (10 µmol/L), 15dPGJ2 (5 µmol/L) or retinoic acid (RA; 10 µmol/L), or in EGM-2 standard medium. Experiments were also performed on cells transiently transfected with the activated form of STAT5 (STAT5 1*6)24 or the empty vector pCNeo.
Isolation and Culture of BM-CACs From Transgenic Mice
Bone marrow (BM)-CACs from wild-type (WT), Tie2-
STAT5A, and Tie2-STAT5B transgenic mice (Tie2-5A and Tie2-5B)16 were isolated and cultured as described in the supplement materials.
Endogenous Depletion of STAT5 and PPAR by Small Interfering RNAs
To obtain inactivation of endogenous STAT5 or PPAR, IL-3-cultured CACs were processed as described in the supplement materials.
Western Blot Analysis and Coimmunoprecipitation Experiments
Cells were lysed and protein concentration was obtained as previously described.25 For co-IP experiments cytosolic and nuclear extracts were obtained as previously described,25 immunoprecipitated (IP) with the indicated antibodies, and processed.
Flow Cytometry
To analyze cell-cycle progression, FACS analysis was performed as previously described25 and in the supplement materials.
RNA Isolation and Quantitative Real-Time Polymerase Chain Reaction
mRNA quantification from CACs, cultured with or without IL-3, as indicated, was performed by quantitative real-time polymerase chain reaction (Q-RT-PCR) as described in the supplement materials. The relative expression of PPAR1 (defined as PPAR throughout the study) and PPAR2 were calculated by using comparative threshold cycle methods. The primer sequences are listed in the supplement materials.
Preparation of Nuclear Extracts and Electrophoretic Mobility Shift Assay
Nuclear extracts from CACs, cultured with or without IL-3, were prepared as described by Sadowski et al26 and used for EMSA, as described in the supplement materials.
Chromatin Immunoprecipitation Assay
Chromatin Immunoprecipitation (ChIP) assay was performed on CACs, recovered from healthy donors and diabetic patients and from WT, Tie2-5A, and Tie2-5B transgenic mice16 using Magna ChIP A kit (Millipore), according to the vendor’s instructions, as described in the supplement materials.
Luciferase-Report Assay
The luciferase reporter assay was performed as described in the supplement materials.
Statistical Analysis
Statistical analysis was performed as described in the supplement materials.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
STAT5 Transcriptional Activity Regulates PPAR
ExpressionWe recently demonstrated that the inflammatory cytokine IL-3, by activating the STAT5 signaling pathway, induces CAC expansion.16 STAT5 dimers bind to specific DNA sequences and regulate the expression of genes involved in different cell functions.27 In addition, STAT5, in concert with PPAR
, modulates tissue specific signals.19–22 Experimental and clinical evidence suggests a crucial role of PPAR in regulating CAC functional activity in diabetic patients.13 To investigate whether a modulatory effect of STAT5 over the PPAR signaling pathway could account for the IL-3–mediated CAC expansion, quantitative real-time PCR and Western blot analysis on IL-3–cultured CACs was first performed. Kinetic analysis (Figure 1A and 1B) demonstrated that PPAR expression, but not PPAR2, temporally correlates with STAT5 activation. In addition, we found that PPAR expression could be prevented by knocking down STAT5 (Figure 1C, left panel). Conversely (Figure 1C), STAT5 expression was not affected by the depletion of PPAR. To verify the involvement of STAT5 in the control of PPAR gene transcription, we selected 5 distinct putative STAT5 response elements in the PPAR gene promoter (supplemental Table I), and used for EMSA. As shown in Figure 2A, reporting a representative consensus sequence (supplemental Table I, sequence 1), when nuclear extracts from IL-3–cultured CACs were assayed for their DNA-binding activity, the formation of PPAR-binding complex was detected. Moreover, STAT5 binding to the DNA-binding complex was confirmed by the supershift assay using the anti-STAT5 antibody (Figure 2A). Similar results were obtained with all STAT5 consensus sequences tested (data not shown). To validate the above data, a C681G site-directed mutagenesis of the STAT5 response element in the PPAR gene promoter28 was performed. Two different constructs, containing the –681C (pGL3C) and the –681G (pGL3G) sequences, were used for the luciferase-reporter assay. As shown in Figure 2B, in CACs expressing the pGL3C PPAR-luciferase-reporter vector, IL-3 was able to induce a high luciferase activity. Conversely, no promoter activity was detected when the pGL3G PPAR-luciferase-reporter vector, containing the sequence corresponding to the mutated STAT5 response element, was used. To further confirm the transcriptional relevance of STAT5 in regulating PPAR expression, ChIP assay was performed on CACs recovered from healthy subjects and from the recently described Tie2STAT5A and Tie2STAT5B transgenic mice.16 The results, reported in Figure 2C and 2D, demonstrate the binding of STAT5 to the genomic DNA region encompassing the putative response elements on the PPAR gene promoter in CACs recovered from humans or from wild-type mice. Conversely, no STAT5 binding could be detected when CACs recovered from Tie2STAT5A or Tie2STAT5B mice were used (Figure 2D).
|
|
Both STAT5-Dependent PPAR Expression and Formation of an Heterodimeric STAT5/PPAR Complex Are Required for CAC Expansion
To determine the role of PPAR in regulating CAC cell-cycle progression, FACS analysis was performed on PPAR silenced cells. As reported in Figure 3A, in these cells IL-3 failed to induce cyclin D1 expression and to promote CAC progression into the cell-cycle. This data indicates that both STAT5 and PPAR are required for CAC expansion, raising the possibility that, by forming an heterodimeric transcriptional complex, STAT5 and PPAR could control the expression of cell-cycle related genes, as cyclin D1. To validate this possibility, coIP experiments were first performed on cytosolic and nuclear extracts obtained from IL-3–cultured CACs. As reported in Figure 3B, although both cellular compartments contained the STAT5/PPAR molecular complex, the complex was mainly present in the nuclear fractions. To further investigate the transcriptional relevance of this heterodimeric complex, ChIP assay was performed. As shown in Figure 3C, either STAT5 and PPAR were able to bind to the genomic DNA region encompassing the putative response elements on the cyclin D1 gene promoter. Conversely, no significant signal was detected using specific primers to the L13A gene (Figure 3C). Thus, these results identify PPAR as a novel STAT5 heterodimeric partner involved in the control of cyclin D1 expression.
|
PPAR Agonists Prevent CAC Expansion
The synthetic ligands thiazolidinediones (TZDs), besides ameliorating insulin sensitivity, also improve CAC functional activity in diabetic patients.13 This prompted us to evaluate whether physiological and synthetic PPAR agonists could, by themselves, promote in vitro expansion of CACs recovered from healthy subjects and diabetic patients. To this end, CACs cultured with troglitazone or with 15 deoxy--12,14-prostaglandin (PG) J2 (15 dPGJ2) were first assayed for PPAR expression. Data reported in Figure 4A demonstrated that PPAR ligands induced PPAR expression both in normal and diabetic CACs, without affecting the promoter activity of the pGL3C PPAR-luciferase-reporter vector (supplemental Figure I). Indeed, as reported in hemopoietic progenitor cells,29 PPAR ligands reduced the expression of STAT5 (Figure 4A) and failed to induce cyclin D1 expression and CAC cell-cycle progression (Figure 4A and 4B). Consistently, no STAT5 and PPAR binding to the putative response elements of cyclin D1 could be detected (Figure 4C). The finding that RA also failed to induce cyclin D1 expression and CAC expansion (data not shown) further confirmed this data, suggesting that STAT5 expression and activation are required to promote CAC expansion. To validate this possibility, the constitutive active STAT5 (STAT5 1*6)24 was used. As shown in Figure 4D and 4E, the constitutively activated STAT5 1*6 prevented TZD effects by rescuing both cyclin D1 expression and progression into the cell-cycle.
|
Diabetic CACs Retain the Ability to Activate the STAT5/PPAR Complex and to Proliferate in a IL-3-Containing Microenvironment
To assess whether the activation of signals upstream to PPAR could partially recover diabetic CAC functions, the cells were cultured in the presence of IL-3. As shown in Figure 5B, IL-3 was able to elicit STAT5 activation, PPAR, and cyclin D1 expression. The finding that the number of cycling cells and of colonies was higher in healthy subjects than in diabetic patients depends on the different number of peripheral blood clonogenic cells (Figure 5A and 5C).30 EGM-2 medium did not significantly affect neither normal nor diabetic CAC expansion, and the activation of signaling pathway leading to this event. To further investigate the role played by STAT5 and PPAR in the control of cyclin D1 expression, ChIP assay was performed. The results, reported in Figure 5D, demonstrate that, similarly to non-diabetic, diabetic CACs, when cultured with IL-3, form a STAT5/PPAR transcriptional complex that binds to the putative response elements and induces the expression of cyclin D1. These data identify IL-3 as a potential modulator of diabetic CACs ex vivo expansion.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Data presented herein lead to the following conclusions: (1) STAT5 transcriptional activity regulates the expression of PPAR
; (2) both STAT5 and PPAR are required for CAC expansion; (3) the STAT5/PPAR transcriptional complex controls cyclin D1 expression; and (4) this complex can partially rescue diabetic CAC bioavailability.
As recently shown, CAC expansion at the site of vascular damage contributes to blood vessel formation.14–16 However, the molecular mechanisms accounting for these events are still under investigation. We recently demonstrated that CACs exposed to IL-3 undergo proliferation, acquire vasculogenic property, and directly participate to neovessel formation by activating the STAT5 signaling pathway.16 The aims of the present study were to characterize the molecular targets of STAT5 in mediating this event and to assess the relevance of this signaling pathway in the control of CAC fate in diabetic setting. Although several lines of evidence indicate that PPAR improves CAC functional activity in diabetic patients,13 the mechanisms associated with this effect are still undefined. We herein demonstrate that PPAR expression temporally correlates with STAT5 activation. In addition, we provide evidence that STAT5 transcriptional activity controls PPAR expression in CACs exposed to an IL-3 containing microenvironment. In addition, by reproducing the –681C/G polymorphism, known to prevent STAT5 binding to the PPAR gene promoter,28 we strengthen the relevance of STAT5 transcriptional activity on PPAR gene expression.
It is known that PPAR mainly forms heterodimers with the nuclear retinoid X receptor (RXR)-.11,12 The PPAR/RXR- heteorodimers are permissive, in that they can be activated by either PPAR or RXR- ligands and they bind to specific PPAR response elements in the regulatory regions of target genes, mainly involved in the anti–inflammatory response and in cell differentiation.2,3,10–12,31 Herein we identify STAT5 as a novel PPAR transcriptional partner and we provide the first evidence that the STAT5/PPAR transcriptional complex is required to control cyclin D1 expression and CAC cell-cycle progression.
PPAR may also interact with other transcription factors, such as the activator protein (AP)-1 and NF-
B, without involving direct DNA binding to regulate gene transcription.31,32 In particular, NF-B is the major target of PPAR to suppress inflammation, a crucial event in the development of vascular dysfunction. Very recently PPAR agonists have been also shown to hamper the functionality of hemopoietic progenitors by inhibiting STAT5 gene expression.29 Consistently, recent reports have mentioned unexplained hematopoietic abnormality in a large cohort of patients with type 2 diabetes participating in clinical trials with the PPAR agonist pioglitazone.33 Finally, Ricote et al34 showed that PPAR ligands can inhibit STAT activity in a PPAR-dependent manner. Similarly, we found that physiological and pharmacological PPAR agonists failed to induce CAC expansion possibly by affecting STAT5 expression, the formation of the STAT5/PPAR transcriptional complex and its binding to the regulatory region of cyclin D1. Indeed, the observation that the expression of the activated variant of STAT5 prevents the inhibitory effect of trogitazone adds further insight into the mechanisms accounting for the results herein presented and for the above mentioned hemopoietic cell defects.
The reduced number and the impaired function of CACs in diabetes have been extensively documented;23,35,36 however, the molecular mechanisms accounting for these events remain to be elucidated. Consistent with previous reports,23,30 we found that the number of CACs recovered from diabetic patients was lower then that from sex and age matched normal subjects. However, diabetic CACs, when exposed to IL-3, acquire the ability to undergo cell cycle progression via STAT5 activation, the formation of the STAT5/PPAR transcriptional complex, and cyclin D1 expression. Currently, impaired CAC functions are considered one mechanism by which risk factors worsen cardiovascular health. Herein, we provide evidence that a cytokine released in inflammatory environments can partially recover CAC bioavailability and possibly vascular regenerative capability in a diabetic setting.
Although human genetic studies and animal studies sustain the beneficial function of PPAR in controlling susceptibility to vascular diseases,10–12 recently reported clinical studies37,38 raise some concern about cardiovascular adverse effects of PPAR agonists. We provide evidence that agonist-independent PPAR expression exerts a pivotal role in preventing vascular damage. Finally, our finding that PPAR, by forming a different heterodimeric complex, can dictate discrete biological responses (supplemental Figure II), may make possible the generation of novel therapeutic strategies able to modulate vascular remodeling.
|
Acknowledgments |
|---|
Sources of Funding
This work was supported by grants of the Italian Association for Cancer Research ( AIRC) to M.F.B.; MIUR ( Ministero dell’Università e Ricerca Scientifica, cofinanziamento MURST and fondi ex-60%) to M.F.B. and L.P.; Ricerca Sanitaria Finalizzata Regione Piemonte to M.F.B.
Disclosures
None.
|
Footnotes |
|---|
P.D. and A.T. equally contributed to this study.
Original received June 16, 2008; final version accepted October 4, 2008.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Centers for Disease Control and Prevention. National Diabetes Fact Sheet (United States). Atlanta, Ga: Centers for Disease Control and Prevention; 2005.
2. Evans RM, Barish GD, Wang YX. PPARs and the complex journey to obesity. Nat Med. 2004; 10: 355–361.[CrossRef][Medline] [Order article via Infotrieve]
3. Kersten S, Desvergne B, Wahli W. Roles of PPARs in health and disease. Nature. 2000; 405: 421–424.[CrossRef][Medline] [Order article via Infotrieve]
4. Krey G, Keller H, Mahfoudi A, Medin J, Ozato K, Dreyer C, Wahli W. Xenopus peroxisome proliferator activated receptors: genomic organization, response element recognition, heterodimer formation with retinoid X receptor and activation by fatty acids. J Steroid Biochem Mol Biol. 1993; 47: 65–73.[CrossRef][Medline] [Order article via Infotrieve]
5. IJpenberg A, Jeannin E, Wahli W, Desvergne B. Polarity and specific sequence requirements of peroxisome proliferator-activated receptor (PPAR)/retinoid X receptor heterodimer binding to DNA. A functional analysis of the malic enzyme gene PPAR response element. J Biol Chem. 1997; 272: 20108–20117.
6. Auwerx J, Martin G, Guerre-Millo M, Staels B. Transcription, adipocyte differentiation, and obesity. J Mol Med. 1996; 74: 347–352.[CrossRef][Medline] [Order article via Infotrieve]
7. Gervois P, Torra IP, Fruchart JC, Staels B. Regulation of lipid and lipoprotein metabolism by PPAR activators. Clin Chem Lab Med. 2000; 38: 3–11.[CrossRef][Medline] [Order article via Infotrieve]
8. Komers R, Vrana A. Thiazolidinediones: tools for the research of metabolic syndrome X. Physiol Res. 1998; 47: 215–225.[Medline] [Order article via Infotrieve]
9. Plutzky J. Peroxisome proliferator-activated receptors in endothelial cell biology. Curr Opin Lipidol. 2001; 12: 511–518.[CrossRef][Medline] [Order article via Infotrieve]
10. Chinetti G, Fruchart JC, Staels B. Peroxisome proliferator-activated receptors (PPARs): nuclear receptors at the crossroads between lipid metabolism and inflammation. Inflamm Res. 2000; 49: 497–505.[CrossRef][Medline] [Order article via Infotrieve]
11. Rizzo G, Fiorucci S. PPARs and other nuclear receptors in inflammation. Curr Opin Pharmacol. 2006; 6: 421–427.[CrossRef][Medline] [Order article via Infotrieve]
12. Duan SZ, Usher MG, Mortensen RM. Peroxisome proliferator-activated receptor-gamma-mediated effects in the vasculature. Circ Res. 2008; 102: 283–294.
13. Wang CH, Ting MK, Verma S, Kuo LT, Yang NI, Hsieh IC, Wang SY, Hung A, Cherng WJ: Pioglitazone increases the numbers and improves the functional capacity of endothelial progenitor cells in patients with diabetes mellitus. Am Heart J. 2006; 152: e1–e8.[CrossRef][Medline] [Order article via Infotrieve]
14. Asahara T, Murohara T, Sullivan A, Silver M, van der Zee R, Li T, Witzenbichler B, Schatteman G, Isner JM. Isolation of putative progenitor endothelial cells for angiogenesis. Science. 1997; 275: 964–967.
15. Prater DN, Case J, Ingram DA, Yoder MC. Working hypothesis to redefine endothelial progenitor cells. Leukemia. 2007; 21: 1141–1149.[CrossRef][Medline] [Order article via Infotrieve]
16. Zeoli A, Dentelli P, Rosso A, Togliatto G, Trombetta A, Damiano L, Francia di Celle P, Pegoraro L, Altruda F, Brizzi MF. Interleukin-3 (IL-3) promotes expansion of hemopoietic-derived CD45+ angiogenic cells and their arterial commitment via STAT5 activation. Blood. 2008; 112: 350–361.
17. Brizzi MF, Dentelli P, Gambino R, Cabodi S, Cassader M, Castelli A, Defilippi P, Pegoraro L, Pagano G. STAT5 activation induced by diabetic LDL depends on LDL glycation and occurs via src kinase activity. Diabetes. 2002; 51: 3311–3317.
18. Ihle JN, Nosaka T, Thierfelder W, Quelle FW, Shimoda K. Jaks and Stats in cytokine signaling. Stem Cells. 1997; 15: 105–111.[CrossRef][Medline] [Order article via Infotrieve]
19. Stephens JM, Morrison RF, Wu Z, Farmer SR. PPARgamma ligand-dependent induction of STAT1, STAT5A, and STAT5B during adipogenesis. Biochem Biophys Res Commun. 1999; 262: 216–222.[CrossRef][Medline] [Order article via Infotrieve]
20. Shipley JM, Waxman DJ. Down-regulation of STAT5b transcriptional activity by ligand-activated peroxisome proliferator-activated receptor (PPAR) alpha and PPARgamma. Mol Pharmacol. 2003; 64: 355–364.
21. Olsen H, Haldosén LA. Peroxisome proliferator-activated receptor gamma regulates expression of signal transducer and activator of transcription 5A. Exp Cell Res. 2006; 312: 1371–1380.[CrossRef][Medline] [Order article via Infotrieve]
22. Dai X, Sayama K, Shirakata Y, Hanakawa Y, Yamasaki K, Tokumaru S, Yang L, Wang X, Hirakawa S, Tohyama M, Yamauchi T, Takashi K, Kagechika H, Hashimoto K. STAT5a/PPARgamma pathway regulates involucrin expression in keratinocyte differentiation. J Invest Dermatol. 2007; 127: 1728–1735.[Medline] [Order article via Infotrieve]
23. Hill JM, Zalos G, Halcox JP, Schenke WH, Waclawiw MA, Quyyumi AA, Finkel T. Circulating endothelial progenitor cells, vascular function, and cardiovascular risk. N Engl J Med. 2003; 348: 593–600.
24. Onishi M, Nosaka T, Misawa K, Mui AL, Gorman D, McMahon M, Miyajima A, Kitamura T. Identification and characterization of a constitutively active STAT5 mutant that promotes cell proliferation. Mol Cell Biol. 1998; 18: 3871–3879.
25. Defilippi P, Rosso A, Dentelli P, Calvi C, Garbarino G, Tarone G, Pegoraro L, Brizzi MF. {beta}1 Integrin and IL-3R coordinately regulate STAT5 activation and anchorage-dependent proliferation. J Cell Biol. 2005; 168: 1099–1108.
26. Sadowski HB, Shuai K, Darnell JE Jr, Gilman MZ. A common nuclear signal transduction pathway activated by growth factor and cytokine receptors. Science. 1993; 261: 1739–1744.
27. Buitenhuis M, Coffer PJ, Koenderman L. Signal transducer and activator of transcription 5 (STAT5). Int J Biochem Cell Biol. 2004; 36: 2120–2124.[CrossRef][Medline] [Order article via Infotrieve]
28. Meirhaeghe A, Fajas L, Gouilleux F, Cottel D, Helbecque N, Auwerx J, Amouyel P. A functional polymorphism in a STAT5B site of the human PPAR gamma 3 gene promoter affects height and lipid metabolism in a French population. Arterioscler Thromb Vasc Biol. 2003; 23: 289–294.
29. Prost S, Le Dantec M, Augé S, Le Grand R, Derdouch S, Auregan G, Déglon N, Relouzat F, Aubertin AM, Maillere B, Dusanter-Fourt I, Kirszenbaum M. Human and simian immunodeficiency viruses deregulate early hematopoiesis through a Nef/PPARgamma/STAT5 signaling pathway in macaques. J Clin Invest. 2008; 118: 1765–1775.[Medline] [Order article via Infotrieve]
30. Fadini GP, Sartore S, Agostini C, Avogaro A. Significance of endothelial progenitor cells in subjects with diabetes. Diabetes Care. 2007; 30: 1305–1313.
31. Berger JP, Akiyama TE, Meinke PT. PPARs: therapeutic targets for metabolic disease. Trends Pharmacol Sci. 2005; 26: 244–251.[CrossRef][Medline] [Order article via Infotrieve]
32. De Bosscher K, Vanden Berghe W, Haegeman G. Cross-talk between nuclear receptors and nuclear factor kappaB. Oncogene. 2006; 25: 6868–6886.[CrossRef][Medline] [Order article via Infotrieve]
33. Berria R, Glass L, Mahankali A, Miyazaki Y, Monroy A, De Filippis E, Cusi K, Cersosimo E, Defronzo RA, Gastaldelli A. Reduction in hematocrit and hemoglobin following pioglitazone treatment is not hemodilutional in Type II diabetes mellitus. Clin Pharmacol Ther. 2007; 82: 275–281.[CrossRef][Medline] [Order article via Infotrieve]
34. Ricote M, Li AC, Willson TM, Kelly CJ, Glass CK. The peroxisome proliferator-activated receptor- is a negative regulator of macrophage activation. Nature. 1998; 391: 79–82.[CrossRef][Medline]
[Order article via Infotrieve]
35. Fadini GP, Agostini C, Avogaro A. Endothelial progenitor cells and vascular biology in diabetes mellitus: current knowledge and future perspectives. Curr Diabetes Rev. 2005; 1: 41–58.[CrossRef][Medline] [Order article via Infotrieve]
36. Rosso A, Balsamo A, Gambino R, Dentelli P, Falcioni R, Cassader M, Pegoraro L, Pagano G, Brizzi MF. p53 Mediates the accelerated onset of senescence of endothelial progenitor cells in diabetes. J Biol Chem. 2006; 281: 4339–4347.
37. Home PD, Pocock SJ, Beck-Nielsen H, Gomis R, Hanefeld M, Jones NP, Komajda M, McMurray JJ; RECORD Study Group: Rosiglitazone evaluated for cardiovascular outcomes–an interim analysis. N Engl J Med. 2007; 357: 28–38.
38. Lincoff AM, Wolski K, Nicholls SJ, Nissen SE. Pioglitazone and risk of cardiovascular events in patients with type 2 diabetes mellitus: a meta-analysis of randomized trials. JAMA. 2007; 298: 1180–1188.
Related Article:
Arterioscler Thromb Vasc Biol 2009 29: 10-11.
This article has been cited by other articles:
 |
|
 |
|
  A. Zampetaki and Q. Xu Vascular Remodeling in Diabetes: Don't Leave Without Your STAT5 Arterioscler Thromb Vasc Biol, January 1, 2009; 29(1): 10 - 11. [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||