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Principal Investigator: Alexander Gitlin
Organization: SLOAN-KETTERING INST CAN RESEARCH
Fiscal Year: 2024
Award: $442,500
Funding agency: NIH Office of the Director
Project Summary/Abstract
Rare monogenic immune disorders have illuminated key aspects of inflammation, but many of the underlying
mechanisms remain poorly understood. For example, autoimmune lymphoproliferative syndrome (ALPS), a
disorder in which T cells fail to undergo apoptosis, is most often caused by genetic defects in the death receptor
FAS or its ligand FASL. However, mutations in caspase-8 or its adaptor FADD – which mediate cell death
downstream of FAS – cause a combination of ALPS plus severe immunodeficiency. Since immunodeficiency is
not generally observed in patients with FAS or FASL mutations, I hypothesized that FADD-caspase-8 must have
an apoptosis-independent function downstream of an immune receptor other than FAS. Indeed, I recently
discovered that activation of multiple immune receptors elicits the caspase-8-mediated cleavage of Nedd4-
binding protein 1 (N4BP1), a novel cytokine suppressor. This represents a critical point of regulation during
inflammation. Notably, deletion of N4BP1 does not ordinarily affect the TRIF-dependent subset of toll-like
receptors (TLRs) that activate caspase-8 (e.g., TLR3 and TLR4). However, the impaired cytokine production of
caspase-8-deficient macrophages stimulated with a TLR4 agonist is restored to normal by co-deletion of N4BP1.
In contrast, N4BP1 deletion leads to exorbitant cytokine responses by the TRIF-independent TLRs (e.g., TLR1/2,
TLR7 and TLR9) that do not directly activate caspase-8. Thus, N4BP1 cleavage by caspase-8 inactivates the
anti-inflammatory activity of intact, un-cleaved N4BP1. These findings offer a novel mechanistic explanation for
immunodeficiency caused by FADD-caspase-8 mutations, whereby the inability to cleave N4BP1 results in its
aberrant persistence and constriction of cytokine responses. Like TLR3 and TLR4 agonists, tumor necrosis factor
(TNF) also leads to caspase-8 cleavage of N4BP1, endowing TNF with the ability to inactivate N4BP1 and
thereby license cytokine production by the TRIF-independent TLRs. This latter finding highlights a key point of
molecular crosstalk between the TNF and TLR systems that converges on caspase-8 cleavage of N4BP1. In the
current proposal, I have linked the mechanism by which N4BP1 suppresses cytokine production to a series of
proteins with both previously recognized and heretofore unknown roles in inflammation. In Aim 1, I will attempt
to decipher the mechanism by which N4BP1 controls the activity of this novel kinase-dependent pathway that
suppresses inflammation. In Aim 2, I will dissect how N4BP1 suppresses late phase inflammatory gene
expression using genome-scale technologies. In Aim 3, I will explore the mechanisms and in vivo consequences
of signal integration by the TNF-caspase-8-N4BP1 axis. Together, these aims will provide novel mechanistic
insights explaining a key regulatory circuit underlying inflammation. They also will serve to launch my
independent research career.
Terms: <(TNF)-α><ALPS-FAS><APO-1 Antigen><APO-1 Cell Surface Antigen><APT1LG1><Adaptor Protein><Adaptor Protein Gene><Adaptor Signaling Protein><Adaptor Signaling Protein Gene><Affect><Agonist><Anti-Inflammatories><Anti-Inflammatory Agents><Anti-inflammatory><Apoptosis><Apoptosis Antigen 1><Apoptosis Pathway><Apoptosis-Related Cysteine Protease Gene Caspase 8><Apoptotic><Apoptotic Cysteine Protease Gene><Apoptotic Protease MCH-5 Gene><Appointment><Area><Autoimmune Status><Autoimmunity><Award><Binding Proteins><Biochemistry><Biological Chemistry><Biological Function><Biological Process><Biology><CAP4><CAP4 protease><CASP8><CASP8 Protein><CASP8 gene><CD178><CD95 Antigens><CD95 molecule><CD95L><CRISPR><CRISPR/Cas system><Cachectin><Canale-Smith Syndrome><Cancers><Career Mobility><Caspase><Caspase Gene><Caspase-8 Gene><Caspase-8/Flice><Cell Body><Cell Communication and Signaling><Cell Culture Techniques><Cell Death><Cell Signaling><Cell-Death Protease><Cells><Cellular Immunology><Cessation of life><Clinical><Clinical Competence><Clinical Pathology><Clustered Regularly Interspaced Short Palindromic Repeats><Communicable Diseases><Competence><Cysteine Endopeptidases><Cysteine Protease><Cysteine Proteinases><Cytokines and Inflammatory Response><DKFZp547I0610><DKFZp564I0682><Data><Death><Dedications><Disease><Disease Progression><Disorder><Endowment><Evaluation><FADD-Homologous ICE/CED3-Like Protease Gene><FADD-Like ICE><FADD-Like ICE Gene><FADD-homologous ICE/CED3-Like Protease><FASL><FLICE><FLICE protein><FLJ11330><Faculty><Funding><GEM model><GEMM model><Gene Expression><Gene Transcription><Genetic><Genetic Alteration><Genetic Change><Genetic Transcription><Genetic defect><Genetically Engineered Mouse><Goals><Health><High-Throughput Nucleotide Sequencing><High-Throughput Sequencing><Homolog of Drosophila TOLL><Human><ICE-Like Apoptotic Protease 5 Gene><ICE-like protease><Image><Immune><Immune Cell Activation><Immune Diseases><Immune Disorders><Immune Dysfunction><Immune System Diseases><Immune System Disorder><Immune System Dysfunction><Immune System and Related Disorders><Immunes><Immunity><Immunodeficiency and Immunosuppression Disorders><Immunoglobulin Enhancer-Binding Protein><Immunologic Diseases><Immunologic Receptors><Immunological Diseases><Immunological Dysfunction><Immunological Receptors><Immunological System Dysfunction><Impairment><In Vitro><Infectious Disease Pathway><Infectious Diseases><Infectious Disorder><Inflammation><Inflammatory><Inflammatory Response Pathway><Innate Immunity><Institution><Intracellular Communication and Signaling><Investigators><KIAA0012><Kinases><Knock-in><Knowledge><Laboratories><Leadership><Licensing><Ligand Binding Protein><Ligand Binding Protein Gene><Ligands><Link><MACH protein><MACH-Alpha-1/2/3 Protein Gene><MACH-Beta-1/2/3/4 Protein Gene><MCH5><MCH5 Isoform Alpha Gene><MORT1-Associated CED-3 Homolog Gene><MORT1-Associated CED3 Homolog Gene><Macrophage><Macrophage-Derived TNF><Malignant Neoplasms><Malignant Tumor><Mch5 protease><Mediating><Medical><Medicine><Mentors><Mentorship><Modern Man><Molecular><Monocyte-Derived TNF><Mutation><Mφ><NF-Kb-Activating Kinase Gene><NF-kB><NF-kappa B><NF-kappaB><NFKB><NIH><National Institutes of Health><Native Immunity><Natural Immunity><Nerve Degeneration><Neuron Degeneration><Non-Specific Immunity><Nonspecific Immunity><Nuclear Factor kappa B><Nuclear Transcription Factor NF-kB><Pathologic><Pathology><Pathway interactions><Patients><Peer Review><Phase><Phosphotransferase Gene><Phosphotransferases><Physicians><Position><Positioning Attribute><Postdoc><Postdoctoral Fellow><Production><Programmed Cell Death><Protein Binding><Proteins><Publications><RNA Expression><Regulation><Research><Research Associate><Research Personnel><Research Proposals><Researchers><Residencies><Resistance><Role><Rotation><Scientific Publication><Scientist><Series><Signal Pathway><Signal Transduction><Signal Transduction Systems><Signaling><Source><Students><System><T-Cells><T-Lymphocyte><T2K><TBK1><TBK1 gene><TLR protein><TLR1><TLR1 gene><TLR1 protein><TLR1 receptor><TLR3><TLR3 gene><TLR4><TLR4 gene><TLR7><TLR7 gene><TNF><TNF A><TNF Alpha><TNF gene><TNF-α><TNFA><TNFRSF6 Receptor><TNFSF6><TNFSF6 gene><TNFα><Techniques><Technology><Therapeutic Intervention><Toll Homologue><Toll-Like Receptor 1><Toll-Like Receptor 3><Toll-Like Receptor 7><Toll-Like Receptor Family Gene><Toll-like receptors><Toll/Interleukin-1 Receptor-Like><Training><Transcript><Transcription><Transcription Factor NF-kB><Transferable Skills><Transphosphorylases><Tumor Necrosis Factor><Tumor Necrosis Factor Receptor Superfamily, Member 6><Tumor Necrosis Factor-alpha><United States National Institutes of Health><Universities><Visit><Work><adapter protein><adaptive immunity><autoimmune lymphoproliferative syndrome><autoinflammatory diseases><autoinflammatory disorders><biological signal transduction><bound protein><career><career advancement><career transition><caspase-8><cell culture><cell cultures><constriction><cystein protease><cystein proteinase><cysteine endopeptidase><cytokine><expectation><experience><faculty support><fas Antigens><fas Receptors><full professor><genetically engineered mouse model><genetically engineered murine model><genome editing><genome mutation><genome scale><genome-wide><genomewide><genomic editing><hypoimmunity><imaging><immune activation><immune deficiency><immune receptor><immunodeficiency><in vivo><insight><instructor><intervention therapy><kappa B Enhancer Binding Protein><knockin><malignancy><meeting><meetings><necrocytosis><neoplasm/cancer><neural degeneration><neurodegeneration><neurodegenerative><neurological degeneration><neuronal degeneration><new drug target><new druggable target><new pharmacotherapy target><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapeutic target><new therapy approaches><new therapy target><new treatment approach><new treatment strategy><novel><novel drug target><novel druggable target><novel pharmacotherapy target><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapeutic target><novel therapy approach><novel therapy target><nuclear factor kappa beta><pathway><phospho-proteomics><phosphoproteomics><post-doc><post-doctoral><post-doctoral trainee><research associates><resistant><response><rsc786><senior faculty><single cell analysis><social role><thymus derived lymphocyte><toll-like receptor 4><undergrad><undergraduate><undergraduate student>