title: Specificity protein-1 as a critical regulator of human cystathionine gamma-lyase in smooth muscle cells.
abstract: Cystathionine γ-lyase (CSE) is the major enzyme in vascular smooth muscle cells (SMCs) that catalyzes the endogenous production of H(2)S. Phenotypic switching of SMCs is affected by endogenous H(2)S level and alterations of this switching may result in vascular disorders. To date, the mechanisms underlying the alteration of CSE expression and H(2)S production in vascular proliferative diseases have been unclear. In the present study, we found that serum deprivation induced SMC differentiation marker gene expressions and increased CSE expression and H(2)S production in cultured human aorta SMCs (HASMCs). Carotid artery ligation in mice resulted in enhanced neointima formation and down-regulation of CSE expression, suggesting an important role of CSE in SMC differentiation. Transient transfection of HASMCs with human CSE (hCSE) promoter/luciferase reporter revealed that the region between -226 to +140 base pair contains the core promoter for the hCSE gene. Deletion and mutation analysis demonstrated that two specificity protein-1 (Sp1) consensus binding sites were present in the core promoter region of the hCSE gene. Incubation of HASMCs with Sp1 binding inhibitor mithramycin inhibited CSE mRNA expression in a dose-dependent manner. Overexpression of Sp1 alone was sufficient to increase the activity of the hCSE core promoter and CSE protein expression. Chromatin immunoprecipitation assay showed that the binding of Sp1 to the hCSE promoter was increased in differentiated HASMCs compared with that in proliferated HASMCs. Exogenously applied H(2)S at 100 μM stimulated SMC differentiation, which was reversed by p38 MAPK inhibitor SB203580. These results suggest that transcript factor Sp1 is a critical regulator of the hCSE expression during SMC differentiation, and CSE/H(2)S system is essential for maintenance of SMC phenotype.
authors.affiliation: School of Kinesiology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada. gyang@lakeheadu.ca
authors.forename: Guangdong
authors.initials: G
authors.lastname: Yang
authors.forename: Yanxi
authors.initials: Y
authors.lastname: Pei
authors.forename: Huajian
authors.initials: H
authors.lastname: Teng
authors.forename: Qiuhui
authors.initials: Q
authors.lastname: Cao
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000494:pharmacology; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003542:Cystathionine gamma-Lyase / Q000096:biosynthesis* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D006862:Hydrogen Sulfide / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism*; D008926:Plicamycin / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020218:Response Elements / Q000502:physiology*; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D000903:Antibiotics, Antineoplastic; D000943:Antigens, Differentiation; D004791:Enzyme Inhibitors; D007093:Imidazoles; D009124:Muscle Proteins; D011725:Pyridines; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D048051:p38 Mitogen-Activated Protein Kinases; D003542:Cystathionine gamma-Lyase; D008926:Plicamycin; C093642:SB 203580; D006862:Hydrogen Sulfide