Current Pilot Project Research Supported by the COBRE
Dr. Reza Izadpanah
Deming Department of Medicine, School of Medicine, Tulane Center for Aging
Targeting TRAF3IP2 Reduces Inflammaging to Improve Anti-Glioblastoma Immunity
Glioblastoma Multiforme (GBM) is the deadliest brain cancer with poor prognosis. Increased age and age-related decline in immune function correlate with GBM incidence, pathogenesis and poor outcome. Aged-mediated increase in chronic inflammation (“inflammaging”), inceased TH17/Treg ratio and decreased cytotoxic CD8 T cell response, which is the primary anti-tumor immune response, contributes to poor outcome in GBM. Tumor Necrosis Factor Receptor Associated Factor 3 Interacting Protein 2 (TRAF3IP2) is a pro-inflammatory adaptive molecule that activates NF-kB and MAPK signaling. TRAF3IP2 is a critical mediator of TH17 mediated inflammation which drives GBM pathogenesis. Our preliminary data demonstrate targeting TRAF3IP2 in GBM suppresses tumor proliferation and metastasis by reducing inflammatory signaling and malignant metabolic pathways. We found that targeting TRAF3IP2 induces senescence in GBM, without a senescence associated secretory phenotype (SASP). TRAF3IP2 mediated activation of GATA4 promotes SASP, which exacerbates inflammaging but also enriches glioma stem cells (GSCs). We demonstrate targeting TRAF3IP2 decreases expression of PD-L1, which is overexpressed by GBM and results in inhibition of anti-tumor CD8+ T cells, and dthat targeting TRAF3IP2 prevents GBM growth and intracranial metastasis and prolongs survival. Specific Aim 1 tests the hypothesis that targeting TRAF3IP2 alters glioblastoma immune landscape in aging to promote anti-tumor immunity. Specific Aim 2 tests the hypothesis that targeting TRAF3IP2 in GBM of aged mice is therapeutic.
Dr. Kislay Parvatiyar
Department of Microbiology and Immunology, School of Medicine, Tulane Center for Aging
Mechanisms of aging dependent inflammation via cytosolic DNA sensing and non- canonical NF-kB pathways
The induction of type I interferon (IFN-I) cytokines plays an essential role in the innate immune response to virus infections by eliciting an antiviral gene program that facilitates the suppression of virus replication and spread. Cytosolic detection of viral nucleic acids by germ-line encoded pattern recognition receptors (PRRs) serves as an initial first step in activating the IFN-I response. Emerging studies, however, have linked previously unknown roles for DNA sensing PRRs in detecting aberrant DNA species of self-origin to trigger the onset of age-related diseases, neurological disorders, and autoinflammatory conditions in the absence of infection. Thus, there is a critical need to delineate the mechanisms by which nucleic acid sensing PRRs control IFN-I activation to develop the next generation of therapeutics to combat viral infections as well as DNA damage driven disease states. We have recently identified a novel crosstalk phenomenon between cytosolic nucleic acid sensing PRRs that activate IFN-I and the non-canonical NF-κB pathway. While the non-canonical NF-kB pathway primarily governs lymphoid organogenesis and B-cell survival and maintenance in response to extracellular ligation of select members of the TNF receptor superfamily, our data unexpectedly revealed that intracellular ligation of nucleic acid sensing cytosolic PRRs also resulted in non-canonical NF-kB activation by causing the turnover of TNF receptor associated factor 3 (TRAF3), a key component of a steady-state negative regulatory complex that persistently causes the destabilization of the non-canonical NF-kB inducing kinase (NIK) which initiates signaling to the non-canonical NF-kB transcription factor complex. Our preliminary data further established that TRAF3 and NIK operate as differential regulators of IFN-I activation downstream of RNA and DNA sensing cytosolic PRRs. However, the mechanisms by which TRAF3 and NIK are controlled to modulate non-canonical NF-kB and IFN-I activation upon nucleic acid detection by cytosolic PRRs are poorly defined. Here we interrogated published data sets that examined TRAF3 and NIK protein interaction networks with a goal of identifying novel candidates with the potential to modulate how the non-canonical NF-kB pathway undergoes activation during cytosolic nucleic acid signaling and how the non-canonical NF-kB effector, NIK cross-talks with the IFN-I signaling platform. We identify synaptosome associated protein 29 (SNAP29) as a TRAF3 interacting partner and zinc finger CCCH-type containing 18 (ZC3H18) as a NIK associated protein and seek to characterize how these proteins modulate TRAF3 and NIK function in the context non-canonical NF-kB and IFN-I pathway activation. Our studies will help define new regulatory elements that control not only antiviral host defense programs, but also immune development and age related autoinflammatory disease states triggered by DNA damage or chromosomal instability.
Dr. Ibolya Rutkai
Department of Pharmacology, School of Medicine, Tulane Center for Aging
Role of mitochondrial fission in the aging cerebral vasculature
Aging is a major risk factor for cerebrovascular, cardiovascular, or neurodegenerative diseases such as Alzheimer’s disease, one of the leading causes of death in Louisiana. While aging is a natural process affecting us at the body, organ, and cellular levels, the aging-associated cellular and structural alterations contribute to and/or initiate heterogeneous pathophysiological cascades. The chronological order of these events, and their contribution to the development of aging-associated diseases, and the therapeutic potential of mitochondria remain unclear. We will study and identify mechanisms along the mitochondrial fission-beta-oxidation-calcium axis at both micro- and macrovascular levels in old, male, and female wild type mice. We will explore strategies to promote mitochondrial resilience via rejuvenating mitochondria (treatment with SS-31 + Mdivi-1) and minimizing mitochondrial quality control imbalance (treatment with Mdivi-1) to facilitate restoration of vascular function in aging. Electron microscopy will be used to investigate the effects of Mdivi-1 treatment alone, and in combination with SS-31 on mitochondrial integrity. Mitochondrial respirometry will be used to determine fuel source preference, whereas mitochondrial calcium influx and mitochondria-mediated calcium spark activity of large cerebral arteries will be used to determine the role of mitochondrial fission in these processes. High throughput proteomics assay will be used to elucidate proteins that are coupled to mitochondrial fission with focus on respiratory complex proteins, fission/fusion proteins, glycolysis related as well as calcium signalingrelated protein abundance.
