A hallmark of patients with ARDS is the inability to utilize oxygen secondary to mitochondrial damage that profoundly limits generation of chemical energy needed in critically injured patients. The mechanistic basis for mitochondrial injury in ARDS patients is unknown. Cardiolipin is a critical mitochondrial structural lipid that when deficient, leads to loss of mitochondria and cell death. But because of its resemblance to bacterial membranes, we discovered that cardiolipin is a highly toxic damage signal that profoundly disrupts lung homeostasis when released from dying cells (Nature Med 2010). Thus, factors that impair cardiolipin availability might reduce mitochondrial integrity and trigger cell death, releasing preformed cardiolipin externally to elicit adverse effects. In this Project, we have preliminary data indicating that S. aureus linked to sepsis-induced ARDS degrades the key enzyme, cardiolipin synthase 1 (CLS1) required for cardiolipin biosynthesis leading to mitochondrial dysfunction and apoptosis, thereby releasing preformed cardiolipin extracellularly. Further, S. aureus activates an orphan ubiquitin E3 ligase F box protein, termed FBX015, that when recruited to CLS1 is sufficient to ubiquitinate and mediate degradation of CLS1 in epithelia. CLS1 phosphorylation by a kinase, termed Pink1, is a critical recognition signal for FBX015. These observations have led to the overall hypothesis that bacterial-induced mitochondrial dysfunction involves post-translational modification of CLS1 that severely limits intracellular availability of this lipid thereby triggering cell death and extracellular release of preformed cardiolipin. To test this hypothesis, we will determine if acute infection with S. aureus inhibits cardiolipin biosynthesis via Pink1 kinase-induced phosphorylation of CLS1 (Aim 1). We will test how the F-box protein, FBX015, triggers ubiquitin-dependent degradation of CLS1 in a phosphorylation-dependent manner after S. aureus infection to impair mitochondrial homeostasis (Aim 2). These studies will translate our basic observations to an in vivo system by testing efficacy of CLS1 phosphorylation and protease-resistant enzyme mutants, adoptive cell based transfer strategies, and initial design of Pink1/F box inhibitors to lessen the severity of alveolar injury. Execution of these studies will serve as a basis for generation of new small molecule CLS1 activators or novel ubiquitin-kinase antagonists. Completion of these studies will lay the groundwork for a potentially significant conceptual advance with regard to the control of mitochondrial integrity and epithelial cell viability during alveolar injury.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL114453-05
Application #
9393336
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Program Officer
Caler, Elisabet V
Project Start
Project End
2019-12-31
Budget Start
2018-01-01
Budget End
2018-12-31
Support Year
5
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Type
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Shah, Faraaz Ali; Singamsetty, Srikanth; Guo, Lanping et al. (2018) Stimulation of the endogenous incretin glucose-dependent insulinotropic peptide by enteral dextrose improves glucose homeostasis and inflammation in murine endotoxemia. Transl Res 193:1-12
Suber, Tomeka L; Nikolli, Ina; O'Brien, Michael E et al. (2018) FBXO17 promotes cell proliferation through activation of Akt in lung adenocarcinoma cells. Respir Res 19:206
Kitsios, Georgios D; Fitch, Adam; Manatakis, Dimitris V et al. (2018) Respiratory Microbiome Profiling for Etiologic Diagnosis of Pneumonia in Mechanically Ventilated Patients. Front Microbiol 9:1413
Chao, Honglu; Anthonymuthu, Tamil S; Kenny, Elizabeth M et al. (2018) Disentangling oxidation/hydrolysis reactions of brain mitochondrial cardiolipins in pathogenesis of traumatic injury. JCI Insight 3:
Kitsios, Georgios D; McVerry, Bryan J (2018) Host-Microbiome Interactions in the Subglottic Space. Bacteria Ante Portas! Am J Respir Crit Care Med 198:294-297
Lou, Wenjia; Ting, Hsiu-Chi; Reynolds, Christian A et al. (2018) Genetic re-engineering of polyunsaturated phospholipid profile of Saccharomyces cerevisiae identifies a novel role for Cld1 in mitigating the effects of cardiolipin peroxidation. Biochim Biophys Acta Mol Cell Biol Lipids 1863:1354-1368
Anthonymuthu, Tamil S; Kenny, Elizabeth M; Lamade, Andrew M et al. (2018) Oxidized phospholipid signaling in traumatic brain injury. Free Radic Biol Med 124:493-503
Hassannia, Behrouz; Wiernicki, Bartosz; Ingold, Irina et al. (2018) Nano-targeted induction of dual ferroptotic mechanisms eradicates high-risk neuroblastoma. J Clin Invest 128:3341-3355
Meiners, Silke; Evankovich, John; Mallampalli, Rama K (2018) The ubiquitin proteasome system as a potential therapeutic target for systemic sclerosis. Transl Res 198:17-28
Gaschler, Michael M; Andia, Alexander A; Liu, Hengrui et al. (2018) FINO2 initiates ferroptosis through GPX4 inactivation and iron oxidation. Nat Chem Biol 14:507-515

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