We have made the seminal observation that O-linked ?-N-acetylglucosamine (O-GlcNAc) modification of proteins induced by three distinct and independent stimuli, 17-? estradiol (E2), glucosamine (GlcN) and the selective O-GlcNAcase inhibitor O-(acetamido-2-deoxy-D-glucopyranosylidene) amino-N-phenylcarbamate (PUGNAc), has anti-inflammatory effects in balloon injured rat carotid arteries. These novel observations provide provocative evidence that enhanced O-GlcNAc modification of proteins has anti-inflammatory and vasoprotective effects in the setting of acute endoluminal vascular injury. We have strong evidence that increased protein O-GlcNAc modification in response to GlcN treatment is associated with attenuation of TNF- ?-induced expression of inflammatory mediators in isolated rat aortic smooth muscle cells (RASMCs) in a manner previously reported for E2. We have utilized the TNF-?-treated RASMC as an in vitro model of the acute vascular injury response and have begun to define the mechanisms by which interventions that stimulate protein O-GlcNAc modification, i.e., E2 and GlcN, inhibit inflammatory responses to TNF-?. We have focused on the NF?B signaling pathway, which is known to be activated by both TNF-? and acute vascular injury. Initial experiments demonstrated that GlcN inhibits TNF-?-induced NF?B activation in RASMCs. Subsequent studies showed that pretreatment with GlcN inhibits TNF-?-induced phosphorylation and degradation of I?B? in RASMCs, while E2 pretreatment is associated with an initial reduction, followed by an accelerated reappearance of I?B? in TNF-? treated cells, likely reflecting new protein synthesis mediated by activated NF?B. The current study will test directly the hypothesis that O-GlcNAc modification of proteins, including I?B?, plays a mechanistic role in regulating the inflammatory response to endoluminal arterial injury in vivo and to TNF-? stimulation in isolated RASMCs in vitro.
The Specific Aims are:
Specific Aim 1 : To test the hypothesis that increasing protein O-GlcNAc modification protects arteries from inflammatory stress related to acute endoluminal injury in vivo via inhibition of NF?B signaling.
Specific Aim 2 : To test the hypothesis that increasing protein O-GlcNAc modification inhibits TNF-?-induced inflammatory responses in RASMCs in vitro via inhibition of NF?B signaling and define the precise sites in the NF?B signaling cascade that are responsible for this effect.
Specific Aim 3 : To identify specific protein targets of O-GlcNAc modification in RASMCs that play a functional role in the anti-inflammatory effects of GlcN and E2. Upon successful completion of these Aims, cellular/molecular mechanisms responsible for the anti-inflammatory and vasoprotective actions of O- GlcNAc modification will be elucidated and will be related to the extent of the injury response (i.e., inflammation and neointima formation). We postulate that O-GlcNAc modification represents a novel mechanism of vasoprotection that may lend itself to the development of new strategies for the prevention and treatment of cardiovascular disease.
This proposal will test the hypothesis that a novel mechanism, O-linked acetylglucosamine (O-GlcNAc) modification of proteins, has anti-inflammatory and vasoprotective effects in injured arteries and cytokine- stimulated smooth muscle cells (SMCs) and will identify the specific proteins that are responsible for these protective effects.
|Giordano, Samantha; Zhao, Xiangmin; Chen, Yiu-Fai et al. (2017) Induced Pluripotent Stem Cell-Derived Endothelial Cells Overexpressing Interleukin-8 Receptors A/B and/or C-C Chemokine Receptors 2/5 Inhibit Vascular Injury Response. Stem Cells Transl Med 6:1168-1177|
|Giordano, Samantha; Zhao, Xiangmin; Xing, Daisy et al. (2016) Targeted delivery of human iPS-ECs overexpressing IL-8 receptors inhibits neointimal and inflammatory responses to vascular injury in the rat. Am J Physiol Heart Circ Physiol 310:H705-15|
|Giordano, Samantha; Hage, Fadi G; Xing, Dongqi et al. (2015) Estrogen and Cardiovascular Disease: Is Timing Everything? Am J Med Sci 350:27-35|
|Bowling, Meaghan R; Xing, Dongqi; Kapadia, Akash et al. (2014) Estrogen effects on vascular inflammation are age dependent: role of estrogen receptors. Arterioscler Thromb Vasc Biol 34:1477-1485|
|Fu, Jinyan; Chen, Yiu-Fai; Zhao, Xiangmin et al. (2014) Targeted delivery of pulmonary arterial endothelial cells overexpressing interleukin-8 receptors attenuates monocrotaline-induced pulmonary vascular remodeling. Arterioscler Thromb Vasc Biol 34:1539-47|
|Hage, Fadi G; Oparil, Suzanne (2013) Ovarian hormones and vascular disease. Curr Opin Cardiol 28:411-6|
|Hilgers, Rob H P; Xing, Dongqi; Gong, Kaizheng et al. (2012) Acute O-GlcNAcylation prevents inflammation-induced vascular dysfunction. Am J Physiol Heart Circ Physiol 303:H513-22|
|Xing, Dongqi; Oparil, Suzanne; Yu, Hao et al. (2012) Estrogen modulates NF?B signaling by enhancing I?B? levels and blocking p65 binding at the promoters of inflammatory genes via estrogen receptor-?. PLoS One 7:e36890|
|Hilgers, Rob H P; Oparil, Suzanne; Wouters, Wout et al. (2012) Vasorelaxing effects of estetrol in rat arteries. J Endocrinol 215:97-106|
|Gong, Kaizheng; Chen, Yiu-Fai; Li, Peng et al. (2011) Transforming growth factor-? inhibits myocardial PPAR? expression in pressure overload-induced cardiac fibrosis and remodeling in mice. J Hypertens 29:1810-9|
Showing the most recent 10 out of 16 publications