Leptin augments recruitment of IRF-1 and CREB to thrombospondin-1 gene promoter in vascular smooth muscle cells in vitro.
*cAMP response element-binding protein; *interferon regulatory factor-1; *leptin; *thrombospondin-1; *transcription; *vascular smooth muscle cells; Binding Sites/genetics; Cells; Chromatin Immunoprecipitation/methods; Cultured; Cyclic AMP Response Element-Binding Protein/*metabolism; Gene Expression Regulation/genetics; Genetic/genetics; Humans; Interferon Regulatory Factor-1/*metabolism; Leptin/*metabolism; Muscle; Mutagenesis; Myocytes; Promoter Regions; Response Elements/genetics; Site-Directed/methods; Smooth; Smooth Muscle/*metabolism; Thrombospondin 1/*genetics/*metabolism; Transcription; Transcriptional Activation/genetics; Transfection/methods; Up-Regulation/genetics; Vascular/*metabolism
We previously reported that high pathophysiological concentrations of leptin, the adipocyte-secreted peptide, upregulate the expression of a potent proatherogenic matricellular protein, thrombospondin-1 (TSP-1), in vascular smooth muscle cells. Moreover, this regulation was found to occur at the level of transcription; however, the underlying molecular mechanisms remain unknown. The goal of the present study was to investigate the specific transcriptional mechanisms that mediate upregulation of TSP-1 expression by leptin. Primary human aortic smooth muscle cell cultures were transiently transfected with different TSP-1 gene (THBS1) promoter-linked luciferase reporter constructs, and luciferase activity in response to leptin (100 ng/ml) was assessed. We identified a long THBS1 promoter (-1270/+750) fragment with specific leptin response elements that are required for increased TSP-1 transcription by leptin. Promoter analyses, protein/DNA array and gel shift assays demonstrated activation and association of transcription factors, interferon regulatory factor-1 (IRF-1) and cAMP response element-binding protein (CREB), to the distal fragment of the THBS1 promoter in response to leptin. Supershift, chromatin immunoprecipitation, and coimmunoprecipitation assays revealed formation of a single complex between IRF-1 and CREB in response to leptin; importantly, recruitment of this complex to the THBS1 promoter mediated leptin-induced TSP-1 transcription. Finally, binding sequence decoy oligomer and site-directed mutagenesis revealed that regulatory elements for both IRF-1 (-1019 to -1016) and CREB (-1198 to -1195), specific to the distal THBS1 promoter, were required for leptin-induced TSP-1 transcription. Taken together, these findings demonstrate that leptin promotes a cooperative association between IRF-1 and CREB on the THBS1 promoter driving TSP-1 transcription in vascular smooth muscle cells.
Sahu Soumyadip; Ganguly Rituparna; Raman Priya
American journal of physiology. Cell physiology
2016
2016-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpcell.00068.2016" target="_blank" rel="noreferrer noopener">10.1152/ajpcell.00068.2016</a>
The role of mitochondrial bioenergetics and reactive oxygen species in coronary collateral growth.
*Collateral Circulation; *Coronary Circulation; *Energy Metabolism; *Neovascularization; angiogenesis; Animals; arteriogenesis; Coronary Vessels/metabolism; Humans; mitochondria; Mitochondria; Mitochondrial Proteins/metabolism; Muscle; Muscle/*metabolism; Myocytes; Oxidative Stress; Phenotype; Physiologic; Reactive Oxygen Species/*metabolism; redox-dependent signaling; Signal Transduction; Smooth; Smooth Muscle/*metabolism; Vascular/*metabolism
Coronary collateral growth is a process involving coordination between growth factors expressed in response to ischemia and mechanical forces. Underlying this response is proliferation of vascular smooth muscle and endothelial cells, resulting in an enlargement in the caliber of arterial-arterial anastomoses, i.e., a collateral vessel, sometimes as much as an order of magnitude. An integral element of this cell proliferation is the process known as phenotypic switching in which cells of a particular phenotype, e.g., contractile vascular smooth muscle, must change their phenotype to proliferate. Phenotypic switching requires that protein synthesis occurs and different kinase signaling pathways become activated, necessitating energy to make the switch. Moreover, kinases, using ATP to phosphorylate their targets, have an energy requirement themselves. Mitochondria play a key role in the energy production that enables phenotypic switching, but under conditions where mitochondrial energy production is constrained, e.g., mitochondrial oxidative stress, this switch is impaired. In addition, we discuss the potential importance of uncoupling proteins as modulators of mitochondrial reactive oxygen species production and bioenergetics, as well as the role of AMP kinase as an energy sensor upstream of mammalian target of rapamycin, the master regulator of protein synthesis.
Pung Yuh Fen; Sam Wai Johnn; Hardwick James P; Yin Liya; Ohanyan Vahagn; Logan Suzanna; Di Vincenzo Lola; Chilian William M
American journal of physiology. Heart and circulatory physiology
2013
2013-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00077.2013" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00077.2013</a>
Sexual dimorphism in prostanoid-potentiated vascular contraction: roles of endothelium and ovarian steroids.
*Sex Characteristics; Animals; Aorta/drug effects/physiology; Bridged Bicyclo Compounds; Cyclooxygenase Inhibitors/pharmacology; Endothelium; Enzyme Inhibitors/pharmacology; Estrogens/*physiology; Fatty Acids; Female; Heterocyclic; Hydrazines/pharmacology; Imidazoles/pharmacology; Indomethacin/pharmacology; Male; Ovariectomy; Phenylephrine/pharmacology; Progesterone/*physiology; Prostaglandins/*metabolism; Rats; Sprague-Dawley; Thromboxanes/metabolism; Unsaturated; Vascular/*metabolism; Vasoconstriction/drug effects/*physiology; Vasoconstrictor Agents/pharmacology; Vasopressins/pharmacology
The effects of constrictor prostanoid (CP) pathway inhibitors on vascular reactivity to vasopressin (VP) and phenylephrine (PE) were examined in thoracic aortas of male, female, and ovariectomized (OVX) female Sprague-Dawley rats. Maximal contractile response of control (Cont) aortas to VP was markedly higher in females (3,885 +/- 332 mg/mg ring wt) than in males (810 +/- 148 mg). Indomethacin (Indo; 10 microM) attenuated maximal response to VP in females (3,043 +/- 277 mg) but not in males. SQ-29,548 (SQ; 1 microM) attenuated maximal response to VP in females (3,042 +/- 290 mg) to a similar extent as Indo. Dazoxiben (Daz; 10 microM) alone had no effect, but Daz + SQ attenuated maximal contractile response to VP to a similar extent as SQ alone. Removal of the endothelium in female aortas attenuated contractile responses to VP in Cont aortas. OVX attenuated maximal contractile response to VP in Cont aortas (2,093 +/- 329 mg) and abolished the attenuating effects of Indo. Indo, SQ, and Daz exerted identical effects on contractile responses of male, female, and OVX female aortas to PE. These findings establish the following in the rat aorta: 1) CP, probably thromboxane and/or endoperoxide, is responsible for approximately
Fulton Clifford T; Stallone John N
American journal of physiology. Heart and circulatory physiology
2002
2002-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajpheart.00099.2002" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.00099.2002</a>
Requisite Role of Kv1.5 Channels in Coronary Metabolic Dilation.
129 Strain; Animals; cardiac function; contrast echocardiography; Coronary Circulation/*physiology; Coronary Vessels/*metabolism; hydrogen peroxide; Inbred C57BL; ion channel; Knockout; Kv1.5 Potassium Channel/*physiology; Mice; Muscle; Smooth; Transgenic; transgenic mice; Vascular/*metabolism; vasodilation; Vasodilation/*physiology; voltage-gated potassium channels
RATIONALE: In the working heart, coronary blood flow is linked to the production of metabolites, which modulate tone of smooth muscle in a redox-dependent manner. Voltage-gated potassium channels (Kv), which play a role in controlling membrane potential in vascular smooth muscle, have certain members that are redox-sensitive. OBJECTIVE: To determine the role of redox-sensitive Kv1.5 channels in coronary metabolic flow regulation. METHODS AND RESULTS: In mice (wild-type [WT], Kv1.5 null [Kv1.5(-/-)], and Kv1.5(-/-) and WT with inducible, smooth muscle-specific expression of Kv1.5 channels), we measured mean arterial pressure, myocardial blood flow, myocardial tissue oxygen tension, and ejection fraction before and after inducing cardiac stress with norepinephrine. Cardiac work was estimated as the product of mean arterial pressure and heart rate. Isolated arteries were studied to establish whether genetic alterations modified vascular reactivity. Despite higher levels of cardiac work in the Kv1.5(-/-) mice (versus WT mice at baseline and all doses of norepinephrine), myocardial blood flow was lower in Kv1.5(-/-) mice than in WT mice. At high levels of cardiac work, tissue oxygen tension dropped significantly along with ejection fraction. Expression of Kv1.5 channels in smooth muscle in the null background rescued this phenotype of impaired metabolic dilation. In isolated vessels from Kv1.5(-/-) mice, relaxation to H2O2 was impaired, but responses to adenosine and acetylcholine were normal compared with those from WT mice. CONCLUSIONS: Kv1.5 channels in vascular smooth muscle play a critical role in coupling myocardial blood flow to cardiac metabolism. Absence of these channels disassociates metabolism from flow, resulting in cardiac pump dysfunction and tissue hypoxia.
Ohanyan Vahagn; Yin Liya; Bardakjian Raffi; Kolz Christopher; Enrick Molly; Hakobyan Tatevik; Kmetz John; Bratz Ian; Luli Jordan; Nagane Masaki; Khan Nadeem; Hou Huagang; Kuppusamy Periannan; Graham Jacqueline; Fu Frances Kwan; Janota Danielle; Oyewumi Moses O; Logan Suzanna; Lindner Jonathan R; Chilian William M
Circulation research
2015
2015-09
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1161/CIRCRESAHA.115.306642" target="_blank" rel="noreferrer noopener">10.1161/CIRCRESAHA.115.306642</a>