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 #
5P01HL029582-29
Application #
8378185
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
29
Fiscal Year
2012
Total Cost
$261,118
Indirect Cost
$94,222
Name
Cleveland Clinic Lerner
Department
Type
DUNS #
135781701
City
Cleveland
State
OH
Country
United States
Zip Code
44195
Herjan, Tomasz; Hong, Lingzi; Bubenik, Jodi et al. (2018) IL-17-receptor-associated adaptor Act1 directly stabilizes mRNAs to mediate IL-17 inflammatory signaling. Nat Immunol 19:354-365
Robinet, Peggy; Milewicz, Dianna M; Cassis, Lisa A et al. (2018) Consideration of Sex Differences in Design and Reporting of Experimental Arterial Pathology Studies-Statement From ATVB Council. Arterioscler Thromb Vasc Biol 38:292-303
Zhang, Cun-Jin; Wang, Chenhui; Jiang, Meiling et al. (2018) Act1 is a negative regulator in T and B cells via direct inhibition of STAT3. Nat Commun 9:2745
Han, Juying; Enyindah-Asonye, Gospel; Lin, Feng et al. (2018) CD6 expression has no effect on atherosclerosis in apolipoprotein E-deficient mice. BMC Res Notes 11:229
Sarvestani, Samaneh K; Signs, Steven A; Lefebvre, Veronique et al. (2018) Cancer-predicting transcriptomic and epigenetic signatures revealed for ulcerative colitis in patient-derived epithelial organoids. Oncotarget 9:28717-28730
Arif, Abul; Yao, Peng; Terenzi, Fulvia et al. (2018) The GAIT translational control system. Wiley Interdiscip Rev RNA 9:
Hai, Qimin; Ritchey, Brian; Robinet, Peggy et al. (2018) Quantitative Trait Locus Mapping of Macrophage Cholesterol Metabolism and CRISPR/Cas9 Editing Implicate an ACAT1 Truncation as a Causal Modifier Variant. Arterioscler Thromb Vasc Biol 38:83-91
Eswarappa, Sandeep M; Potdar, Alka A; Sahoo, Sarthak et al. (2018) Metabolic origin of the fused aminoacyl-tRNA synthetase, glutamyl-prolyl-tRNA synthetase. J Biol Chem 293:19148-19156
Halawani, Dalia; Gogonea, Valentin; DiDonato, Joseph A et al. (2018) Structural control of caspase-generated glutamyl-tRNA synthetase by appended noncatalytic WHEP domains. J Biol Chem 293:8843-8860
Shao, Xinrui; Chen, Siyuan; Yang, Daping et al. (2017) FGF2 cooperates with IL-17 to promote autoimmune inflammation. Sci Rep 7:7024

Showing the most recent 10 out of 276 publications