Grant: Foundation Grant

Cancer; Cardiorespiratory; Confocal Microscopy; Dynamin Related Protein 1 (Drp1); Metabolism; Mitochondria; Mitochondrial Dynamics; Oxygen Sensing; Pulmonary Hypertension; Right Ventricle

<html> <body> <p>PAH is a disease of the cardiopulmonary unit (PA circulation and RV). PAH cells, including smooth muscle cells, have a cancer-like, proliferative, apoptosis-resistant, metabolically reprogrammed phenotype¹²^,^20-24. The resulting obstructive vasculopathy increases RV afterload causing fatal RV failure²⁵. NSCLC has similar abnormalities of proliferation, apoptosis and metabolism. We¹³^,¹⁵^,^26-28 and others^29-31 discovered that this shared phenotype reflects disorders of mitochondrial metabolism (a shift to aerobic glycolysis) and mitochondrial dynamics (fragmentation due to activation of the fission mediator, dynamin related protein 1, Drp1, and downregulation of the fusion mediator, mitofusin-2, Mfn2).</p> <p>PAH therapies are vasodilators and do not address the disease&rsquo;s &ldquo;neoplastic&rdquo; phenotype or regress vascular disease³². NSCLC therapies interfere with DNA replication and have dose-limiting toxicity. Consequently survival in PAH and NSCLC is poor. Preclinical studies targeting mitochondrial metabolism (inhibiting PDK¹³^,²⁷) or dynamics (inhibiting Drp1 or overexpressing Mfn2) regress PAH and NSCLC with little toxicity ⁸^,⁹^,³³. Drp1 inhibition (mdivi-1) or Mfn2 gene therapy (Adv-Mfn2)⁸^,⁹ appear to work by inhibiting mitotic fission, which triggers cell cycle arrest and apoptosis⁹.</p> <p> <strong>Goal:</strong> Define the molecular basis for abnormal fission and fusion in PAH and NSCLC and translate this knowledge into new therapies.</p> <p> <br> </p> <p> <strong>Objectives: In PAH and NSCLC</strong> </p> <p>1. Determine the mitochondrial fission complex&rsquo;s composition using super resolution microscopy</p> <p>2. Determine the role of Drp1 binding partners, MiD49, MiD51, MFF and/or Fis1, in regulating mitochondrial morphology and cell proliferation, migration and apoptosis</p> <p>3. Develop mitochondrial therapeutics, including novel Drp1 inhibitors, phosphorylation-resistant Mfn2 mutants and MiD49 and MiD51 inhibitors</p> <p>4. Establish the relationship between fusion and oxidative metabolism</p> <p>5. Define the role of PKA-induced proteosomal degradation of Mfn2 and assess the therapeutic effects of Mfn2 phosphorylation mutants</p> <p>6. Determine the role of fission in RV ischemia-reperfusion injury (RV-IR)</p> <p> <br> </p> <p> <strong>Preliminary data</strong> </p> <p>1. We can image the fission complex and quantify fragmentation and fusion</p> <p>2. Upregulation of MiD49 and MiD51 drive proliferation in PAH and NSCLC</p> <p>3. There is heterogeneous MiD49 and MiD51 expression amongst patients</p> <p>4. PKA-induced phosphorylation of serine 442 triggers proteosomal degradation of Mfn2</p> <p>5. Mitochondrial fission results in RV-IR</p> <p>6. We discovered 5 molecules with putative anti-Drp1 activity and several are superior to mdivi-1</p> <p> <br> </p> <p> <strong>Anticipated Results</strong> </p> <p>Fundamental discoveries will inform development, testing, and patenting of new therapies. A partnership with Queen&rsquo;s PARTEQ group will facilitate commercialization of intellectual property (IP). Knowledge translation (KT) will occur by publication, conferences, my blog and the Pulmonary Vascular Research Institute (PVRI), a global KT group for which I am North American co-lead.</p> <p> <br> </p> <p> <strong>Core expertise</strong> </p> <p>I have studied PAH since 1983 and NSCLC since 2005. I have the expertise and infrastructure to complete the proposed experiments. My team includes a mitochondrial biologist, a confocal microscopist, and a physiologist. Collaborators include a synthetic chemist, a KT group (PVRI) and an IP group (PARTEQ).</p> <p> <br> </p> <p> <strong>Mentoring/training</strong> </p> <p>My lab has a track record for training independent investigators. Currently I mentor 5 junior faculty and 3 postdoctoral fellows. This grant will double my training capacity.</p> </body> </html>