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Transcript-selective translational control of Th17 cell development and function

Th17 细胞发育和功能的转录选择性翻译控制

基本信息

批准号：
10373280
负责人：
Mark Scott Sundrud
金额：
$ 9.14万
依托单位：
SCRIPPS FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-27 至 2022-04-01
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10373280
关键词：
3&apos Untranslated Regions Acute Adaptor Signaling Protein Amino Acids Amino Acyl-tRNA Synthetases Anti-Inflammatory Agents Antiinflammatory Effect Autoimmune Binding Biology CD4 Positive T Lymphocytes Catalytic Domain Cell Differentiation process Cell Lineage Cell physiology Cells Charge Chemicals Collaborations Complex Coupled Data Development Elements Engineering Enzymes Epigenetic Process Eye FRAP1 gene Family GCN2 protein kinase Gait Genetic Genetic Transcription Halofuginone Helper-Inducer T-Lymphocyte Homeostasis Human Immune Immune response Immunoprecipitation Inflammation Inflammatory Interferon Type II Interleukin-17 Interleukin-6 Link Maps Mediating Messenger RNA Mus Natural Products Pathogenicity Pathology Pathway interactions Pharmacology Plants Property Protein Biosynthesis Protein Family Protein Kinase Proteins RNA Binding RNA Interference Regulatory T-Lymphocyte Reporter Reporting Research RiboTag Ribosomal Proteins Ribosomes Role Signal Transduction Starvation Stat3 protein Stromal Cells Structure System Therapeutic Transcript Transfer RNA Transfer RNA Aminoacylation Translational Regulation Translational Repression Translations Yeasts acid stress base biological adaptation to stress chronic inflammatory disease cytokine deprivation experimental study febrifugine immunoregulation in vivo inhibitor/antagonist insight interleukin-23 macrophage medical schools novel novel drug class novel strategies novel therapeutics proline-tRNA receptor response scaffold sensor small molecule stem transcriptome sequencing translatome treatment strategy

项目摘要

Project Summary Differentiation of naïve CD4+ T helper (TH) cells into effector or regulatory subsets determines whether an immune response is protective, ineffective or pathogenic. Through a standing collaboration with Dr. Malcolm Whitman, we have shown that the febrifugine family of plant natural products—including the synthetic derivative halofuginone (HF)—potently and selectively blocks human and mouse Th17 cell differentiation by activating a conserved stress response pathway, called the amino acid response (AAR). We further showed that HF activates the AAR by binding to the catalytic domain of the mammalian prolyl-tRNA synthetase, EPRS, and inhibiting prolyl-tRNA aminoacylation (i.e., charging). Uncharged tRNAs accumulate in cells during periods of amino acid restriction, and signal sequential translational and transcriptional responses via the ribosome- associated protein kinase, Gcn2, to reduce amino acid demand, increase amino acid supply and facilitate a return to homeostasis. Although HF-mediated EPRS inhibition induces rapid accumulation of uncharged prolyl- tRNAs and Gcn2 activation, we have shown that HF-mediated EPRS inhibition acts independent of known amino acid sensing pathways, including Gcn2, to repress both IL-6-driven Th17 cell differentiation and IL-23- induced ‘pathogenic’ Th17 cell function by selectively repressing Stat3 protein synthesis (i.e., translation). This proposal interrogates two pathways that we hypothesize underlie HF/EPRS-mediated Stat3 translational silencing. First, EPRS (the cellular receptor for HF) has an auxiliary, or ‘moonlighting’, function as the RNA- binding sub-unit of a transcript-selective translational regulatory complex, called GAIT (gamma interferon- activated inhibitor of translation). Assembled GAIT complexes bind and repress translation of select sets of inflammation-associated transcripts containing structurally conserved stem-loop motifs in their 3’ untranslated regions (UTRs), but has yet to be formally evaluated in TH cells. Second, we have shown that both HF- mediated AAR activation (Gcn2-dependent) and HF-dependent anti-inflammatory reprogramming (Gcn2- independent) in stromal cells requires another ribosome-associated protein, Gcn1. Although Gcn1 is known only for enhancing Gcn2-binding to uncharged tRNAs, our data suggest that Gcn1 can be functionally uncoupled from Gcn2, and may serve as a branch point from the canonical AAR pathway in cells responding to amino acid stress. To elucidate the contribution of these pathways to cellular responses to amino acid deprivation, and with an eye towards engineering new drug-like small molecules that retain Stat3 translational silencing activity without inhibiting an essential enzyme (EPRS), we will: (i) employ EPRS immunoprecipitation experiments to assess HF-driven GAIT complex assembly and Stat3 mRNA-binding in developing Th17 cells; and (ii) use inducible RNAi coupled with Ribo-tag mice to determine if HF/EPRS-mediated Stat3 translational repression requires Gcn1.Together, these studies will reveal novel insights into the translational regulation of TH cell differentiation, and inform new, more selective approaches to treat Th17-driven immune pathologies.

项目总结