2019 Fiscal Year Research-status Report
Unveiling Novel STAT1 Activation Expands its Anti-viral Role into Host Defense Against Bacterial Pathogens
| Project/Area Number |
19K23864
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| Research Institution | Osaka University |
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Principal Investigator |
METWALLY HOZAIFA 大阪大学, 免疫学フロンティア研究センター, 特任研究員 (40844246)
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| Project Period (FY) |
2019-08-30 – 2021-03-31
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| Keywords | STAT1 / Thr749 / Interferon / TLR4 / Tyr701 |
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| Outline of Annual Research Achievements |
Toll like receptor 4 (TLR4) signaling pathways have been extensively studied for many years. Recently, TLR4 endocytosis has emerged as fundamental step for TRIF signaling followed by type I interferons (IFNs) production, which activate the transcription of antiviral response genes through JAK-STAT1 pTyr701 signaling. However, how TLR4 endosomal signaling promotes proinflammatory cytokines production remains elusive. Our findings unveiled a noncanonical proinflammatory signaling pathway downstream of TLR4 endocytosis where noncanonical phosphorylation of STAT1 at Thr749 residue confers distinct proinflammatory gene-regulatory properties independently of IFNs signaling. Our work highlights the importance of differential phosphorylation STAT1 and how it can affect its transcriptional outcome
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The first part of our study involving the identification of the proinflammatory gene-regulatory properties of the noncanonical STAT1 phosphorylation (pThr749) in human macrophages has been published in Science Signaling journal [Metwally et al., Sci. Signal. 13, eaay0574 (2020)], and highlighted as immunology research in the Science magazine (Science 27 mar 2020: vol. 367, issue 6485, pp. 1438-1440). For the in vivo biological significance of our findings, T748A KI mice were generated in December, 2019 and are being bred for homozygous. For in vitro molecular studies, we successfully generated STAT1 Knock out macrophages cell line to be re reconstituted with different STAT1 constructs for analyzing the effect of different STAT1 phosphorylation on the macrophage function.
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| Strategy for Future Research Activity |
For the in vivo study, we are comparing the response of STAT1 WT, Knock out or T748A KI mice in contexts of LPS challenge and bacterial infection. For in vitro study, we will perform genome wide analysis using RNA-seq, ChIP-seq and LC-MS proteomics, which will be performed in collaboration with Prof. Ichiro Taniuchi (IMS, RIKEN). Also, we are generating phospho-specific Ab against Thr748 STAT1 in collaboration with Prof. Hiroyuki Kishi (Toyama University), which will be helpful in understanding the kinetics of this noncanonical phosphorylation under physiological and inflammatory conditions.
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| Causes of Carryover |
For Travel expenses, I was awarded Milstein Travel Award (\125,375 JPY) from International Cytokine & Interferon Society that covered part of my travel expenses to attend and present at 7th Annual Meeting of the International Cytokine & Interferon Society, Vienna 2019. For research expenses, T748AKI mice generation was technically challenging. Heterozygous males of T748A KI mice were ready for breeding in March 2020. Therefore, we delayed our genome-wide analysis until we get the homozygous mice.
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Research Products
(4 results)
