The long-term goal of Project 2 is to elucidate the post-transcriptional mechanisms that modulate gene expression in inflammation of the vasculature. Interferon (IFN)-v is the classic activator of monocyte/macro- phages, and it induces rapid transcription of inflammatory growth factors, proteases, chemokines, and gen- erators of radical species. If unregulated, this process becomes chronic and monocyte/macrophage products accumulate, damage host tissue, and contribute to chronic disorders of blood vessels, e.g., atherosclerosis. The termination of inflammation is not a passive process that begins after elimination of the initial insult;in contrast, intrinsic mechanisms actively limit expression of potentially injurious proteins. Recently, investigat- ors have recognized the important role of post-transcriptional processes in limiting or resolving inflammation. We have discovered a novel translational control pathway that acts as an endogenous regulator of the inflammatory response. In myeloid cells, IFN-y induces assembly of the heterotetrameric, IFN-Gamma- Activated inhibitor of Translation (GAIT) complex, which binds an RNA element in the 3'untranslated region of certain pro-inflammatory target mRNAs, e.g., vascular endothelial growth factor-A, and inhibits their translation. In Preliminary Studies we show that one GAIT protein, glutamyl-prolyl-tRNA synthetase (EPRS), is central to the GAIT system because it is responsible for target mRNA recognition, and its function is regu- lated by phosphorylation and binding of the other 3 GAIT proteins. We suggest EPRS is not an inert, protein- binding scaffold, but rather a dynamic system subject to stimulus-inducible modifications that regulate GAIT complex assembly and function. Based on these results, we propose the following hypothesis: Phosphoryl- ation of EPRS by IFN-y-dependent kinases causes conformational changes in EPRS that regulate assembly of the GAIT complex, which silences translation of inflammatory mRNA targets and contributes to the resolu- tion of chronic inflammation. We will test this hypothesis by pursuit of three Specific Aims.
In Aim 1 we will determine the EPRS domains required for GAIT complex assembly and GAIT element-binding.
In Aim 2 we will determine the role of EPRS phosphorylation in GAIT complex assembly and function.
In Aim 3 we will investigate the anti-inflammatory function of EPRS and the GAIT complex in vivo.

Public Health Relevance

Our studies will elucidate a new pathway that regulates the synthesis of inflammatory proteins by macrophages, an important process in the development of vascular diseases such as atherosclerosis. The pathway under investigation contributes to the limitation and resolution of chronic inflammation, an important causative factor in disease progression. A deeper understanding of inflammatory "stop" pathways is important because defects in these pathways can contribute to vascular disorders, and because the pathway itself may present alternative targets for development of novel anti- inflammatory therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL029582-30
Application #
8448087
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
30
Fiscal Year
2013
Total Cost
$248,586
Indirect Cost
$90,251
Name
Cleveland Clinic Lerner
Department
Type
DUNS #
135781701
City
Cleveland
State
OH
Country
United States
Zip Code
44195
Zhou, Hao; Yu, Minjia; Zhao, Junjie et al. (2016) IRAKM-Mincle axis links cell death to inflammation: Pathophysiological implications for chronic alcoholic liver disease. Hepatology 64:1978-1993
Smith, Jonathan D (2016) Human Macrophage Genetic Engineering. Arterioscler Thromb Vasc Biol 36:2-3
Harris, Daniel P; Chandrasekharan, Unnikrishnan M; Bandyopadhyay, Smarajit et al. (2016) PRMT5-Mediated Methylation of NF-κB p65 at Arg174 Is Required for Endothelial CXCL11 Gene Induction in Response to TNF-α and IFN-γ Costimulation. PLoS One 11:e0148905
Arif, Abul; Jia, Jie; Halawani, Dalia et al. (2016) Experimental approaches for investigation of aminoacyl tRNA synthetase phosphorylation. Methods :
Antonopoulos, Christina; Russo, Hana M; El Sanadi, Caroline et al. (2015) Caspase-8 as an Effector and Regulator of NLRP3 Inflammasome Signaling. J Biol Chem 290:20167-84
Kasumov, Takhar; Li, Ling; Li, Min et al. (2015) Ceramide as a mediator of non-alcoholic Fatty liver disease and associated atherosclerosis. PLoS One 10:e0126910
Eswarappa, Sandeepa M; Fox, Paul L (2015) Antiangiogenic VEGF-Ax: A New Participant in Tumor Angiogenesis. Cancer Res 75:2765-9
Schonberg, David L; Miller, Tyler E; Wu, Qiulian et al. (2015) Preferential Iron Trafficking Characterizes Glioblastoma Stem-like Cells. Cancer Cell 28:441-55
Wang, Shuhui; Robinet, Peggy; Smith, Jonathan D et al. (2015) Free-cholesterol-mediated autophagy of ORMDL1 stimulates sphingomyelin biosynthesis. Autophagy 11:1207-8
Zhao, Junjie; Bulek, Katarzyna; Gulen, Muhammet F et al. (2015) Human Colon Tumors Express a Dominant-Negative Form of SIGIRR That Promotes Inflammation and Colitis-Associated Colon Cancer in Mice. Gastroenterology 149:1860-1871.e8

Showing the most recent 10 out of 244 publications