IL-33, acting via its receptor, ST2L, is a highly potent cytokine implicated in septic injury. The IL-33/ST2L axis appears indispensable in inflammatory signaling as blockade of the ST2L receptor significantly attenuates systemic inflammation. Thus, maneuvers designed to selectively modulate availability of ST2L might lessen the severity of sepsis. However, to date, very little is known regarding the molecular regulation of ST2L expression. In the process of studying bacterial sepsis, we discovered that a new orphan protein, FBXL19 (F-box protein 19, SCFFBXL19), specifically targets phosphorylated ST2L for its ubiquitination and degradation. Our published and preliminary works also shows that ST2L is phosphorylated by glycogen synthase kinase (GSK3), and that activation of the IL-33/ST2L axis induces cleavage of PARP and PKC thereby promoting apoptosis. Further, FBXL19 mediated disposal of ST2L attenuates IL-33/ST2L-induced pro-inflammatory signaling, apoptosis, and lessens the severity of inflammatory organ injury in septic murine models. These data led to our novel hypothesis that GSK3-driven phosphorylation of ST2L serves as a molecular signature for F-box protein mediated ubiquitination and degradation of ST2L in sepsis-associated injury. We will test this hypothesis by executing two specific Aims: (1) To investigate the mechanisms by which GSK3 promotes ST2L degradation and regulates IL-33/ST2L signaling, and (2) To investigate the mechanisms by which FBXL19 and its ligand promotes ST2L ubiquitination and degradation thereby attenuating septic lung injury. These studies will lay the groundwork for a significant mechanistic advance with regard to the molecular regulation of a relatively new receptor (ST2L) involved in sepsis. Results from these studies are intended to serve as the basis for strategies directed at the development of novel small molecule inhibitors of the IL-33/ST2L pathway to lessen the severity of sepsis-induced organ injury.

Public Health Relevance

Acute lung injury (ALI) is a cause of respiratory failure resulting from acute pulmonary inflammation. Almost half of patients with septic shock develop ALI. These studies will identify molecular mechanisms on how a new protein, termed F-box protein FBXL19, targets a pro-inflammatory cytokine receptor to mediate its degradation. These studies will be critical in developing a novel small molecule as potential therapeutics to lessen the severity of sepsis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL112791-03
Application #
8851660
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Sarkar, Rita
Project Start
2013-06-01
Project End
2016-05-31
Budget Start
2015-06-01
Budget End
2016-05-31
Support Year
3
Fiscal Year
2015
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Li, Shuang; Zhao, Jing; Shang, Dong et al. (2018) Ubiquitination and deubiquitination emerge as players in idiopathic pulmonary fibrosis pathogenesis and treatment. JCI Insight 3:
Li, Shuang; Wang, Dan; Zhao, Jing et al. (2018) The deubiquitinating enzyme USP48 stabilizes TRAF2 and reduces E-cadherin-mediated adherens junctions. FASEB J 32:230-242
Wei, Jianxin; Dong, Su; Yao, Kangning et al. (2018) Histone acetyltransferase CBP promotes function of SCF FBXL19 ubiquitin E3 ligase by acetylation and stabilization of its F-box protein subunit. FASEB J 32:4284-4292
Cai, Junting; Wei, Jianxin; Schrott, Valerie et al. (2018) Induction of deubiquitinating enzyme USP50 during erythropoiesis and its potential role in the regulation of Ku70 stability. J Investig Med 66:1-6
Cai, Junting; Culley, Miranda K; Zhao, Yutong et al. (2018) The role of ubiquitination and deubiquitination in the regulation of cell junctions. Protein Cell 9:754-769
Wang, Dan; Zhao, Jing; Li, Shuang et al. (2018) Phosphorylated E2F1 is stabilized by nuclear USP11 to drive Peg10 gene expression and activate lung epithelial cells. J Mol Cell Biol 10:60-73
Suber, Tomeka; Wei, Jianxin; Jacko, Anastasia M et al. (2017) SCFFBXO17 E3 ligase modulates inflammation by regulating proteasomal degradation of glycogen synthase kinase-3? in lung epithelia. J Biol Chem 292:7452-7461
Wei, Jianxin; Dong, Su; Bowser, Rachel K et al. (2017) Regulation of the ubiquitylation and deubiquitylation of CREB-binding protein modulates histone acetylation and lung inflammation. Sci Signal 10:
Zhao, Yutong; Ridge, Karen; Zhao, Jing (2017) Acute Lung Injury, Repair, and Remodeling: Pulmonary Endothelial and Epithelial Biology. Mediators Inflamm 2017:9081521
Jacko, A M; Nan, L; Li, S et al. (2016) De-ubiquitinating enzyme, USP11, promotes transforming growth factor ?-1 signaling through stabilization of transforming growth factor ? receptor II. Cell Death Dis 7:e2474

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