Caspase-1 is a member of a family of aspartate-specific cysteine proteases, known as the caspase family, involved in apoptosis and inflammation. Recent studies revealed that caspase-1 is activated within large protein complexes or assemblies called the inflammasomes. The inflammasomes are composed of several adaptor proteins that interact with caspase-1 and induce its oligomerization and activation. Preliminary evidence from the applicant's lab suggest that pyrin, a protein mutated in the auto- inflammatory disease Familial Mediterranean fever (FMF), plays a major role in inflammation by assembling an inflammasome complex with the adaptor protein ASC, and procaspase-1 leading to ASC oligomerization, caspase-1 activation and IL-1? processing. Pyrin also appears to play an important role in apoptosis as macrophages from pyrin-truncation mice exhibit a defect in apoptosis compared to macrophages from wildtype mice in response to IL-4 and LPS stimulation. Evidence suggests that the inflammatory and perhaps the apoptotic activities of pyrin are regulated by two cytoskeleton associated proteins known as PSTPIP1 and PSTPIP2. Missense mutations in these proteins are associated with two further auto-inflammatory diseases, known as pyogenic arthritis, pyoderma gangrenosum, acne syndrome (PAPA) and chronic multifocal osteomyelitis (cmo) syndrome, respectively. In this competing continuation application three specific aims are proposed to study the physiological role of pyrin in apoptosis and inflammation and the role of the cytoskeleton in these two pyrin pathways. In the first specific aim, the role of pyrin in caspase-1 activation will be investigated through detailed biochemical and biological studies in cell-based and cell-free reconstitution systems and human and mouse macrophage cell lines. In the second specific aim, experiments are proposed to characterize the interaction of PSTPIP1 and PSTPIP2 with pyrin and determine their ability to regulate caspase-1 activation in human and mouse cells. In the third specific aim, biological, biochemical and genetic approaches will be used to elucidate the mechanism by which pyrin regulates apoptosis. Understanding the interplay of the pyrin-mediated inflammatory and apoptotic responses and the mechanism of activation of caspase-1 by pyrin is likely to contribute important insights into the role of pyrin in innate immunity and apoptosis, with obvious potential clinical applications. Public Health Relevance Statement: Mutations in the genes encoding pyrin and the pyrin-associated protein PSTPIP1 are associated with severe autoinflammatory diseases in humans. This research will investigate the physiological function of pyrin to elucidate its role in normal cellular function and how disease-associated mutations alter its function. The results of this research will help in the design and discovery of effective therapeutics to treat autoinflammatory diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR055398-13
Application #
7781346
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Mancini, Marie
Project Start
1996-08-15
Project End
2013-03-31
Budget Start
2010-04-01
Budget End
2011-03-31
Support Year
13
Fiscal Year
2010
Total Cost
$336,501
Indirect Cost
Name
Thomas Jefferson University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
053284659
City
Philadelphia
State
PA
Country
United States
Zip Code
19107
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Kang, Seokwon; Fernandes-Alnemri, Teresa; Rogers, Corey et al. (2015) Caspase-8 scaffolding function and MLKL regulate NLRP3 inflammasome activation downstream of TLR3. Nat Commun 6:7515
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Ghonime, Mohammed G; Shamaa, Obada R; Das, Srabani et al. (2014) Inflammasome priming by lipopolysaccharide is dependent upon ERK signaling and proteasome function. J Immunol 192:3881-8
Fernandes-Alnemri, Teresa; Kang, Seokwon; Anderson, Connor et al. (2013) Cutting edge: TLR signaling licenses IRAK1 for rapid activation of the NLRP3 inflammasome. J Immunol 191:3995-9
Park, Sangjun; Juliana, Christine; Hong, Sujeong et al. (2013) The mitochondrial antiviral protein MAVS associates with NLRP3 and regulates its inflammasome activity. J Immunol 191:4358-66
Yu, Je-Wook; Farias, Andrew; Hwang, Inhwa et al. (2013) Ribotoxic stress through p38 mitogen-activated protein kinase activates in vitro the human pyrin inflammasome. J Biol Chem 288:11378-83

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