Novel peptides for resuscitation

Cardiac arrest (CA) is a leading cause of death around the globe. In the USA, it affects about 650,000 people annually with an overall survival rate for out-of-hospital cardiac arrest less than 10%. Despite this enormous public health burden, no pharmacological drugs exist to improve CA survival. This proposal is a renewal application of R01HL147031-01 that investigated a novel cell-permeable biological peptide TAT-PHLPP9c to improve CA outcome. This peptide inhibits the phosphatase PHLPP and activates Akt in the heart and brain within minutes after intravenous administration during cardiopulmonary resuscitation (CPR). Remarkable improvement in neurologically intact survival in both mouse and swine CA models was demonstrated, with new biomarkers of metabolic resuscitation identified. However, in addition to metabolic dysfunction, marked intravascular coagulation in the microcirculation of organs after CA also contributes to poor outcomes. This renewal application builds upon new preliminary data showing that in addition to Akt-related metabolic recovery, platelet activation and related thrombo-inflammation via the G Protein α13-Integrin β3 interaction affects CA outcome. Proposed work will examine a novel treatment strategy for CA that combines the use of TAT-PHLPP9c and M3mP6, a lipid-stabilized, high-loading peptide nanoparticle designed to inhibit integrin signaling and platelet activation. Our pilot studies suggest substantial platelet activation and related inflammation within hours after both mouse and swine CA, with only partial attenuation of this thrombo-inflammation by TAT-PHLPP9c. Furthermore, M3mP6, when given during CPR, provides substantial synergistic benefit from TAT-PHLPP9c to 5-day CA survival in a mouse CA model. New aims will use these two complementary novel peptides to examine the synergistic roles of metabolic derangement and thrombo-inflammation in CA survival, and develop a transformative approach to CA with the potential to protect against even prolonged >10-15 min of untreated cardiac arrest. New proposed work will: Aim 1. Examine whether combined treatment of TAT-PHLPP9c and M3mP6 during CPR improves 5-day neurologically intact survival after mouse CA. Aim 2. Study the mechanisms of the synergistic effects of these two peptides in the heart and platelets. Aim 3. Validate the efficacy of TAT-PHLPP9c and M3mP6 in a swine CA model. The concept of administration of novel cell-permeable peptides during CPR to protect against two critical aspects of post-CA syndrome is practical, innovative and highly translational. New mechanistic insights into metabolic injury and thrombo-inflammation and how they interact to affect CA survival would have great potential to develop novel approaches for CA care. Given the magnitude of protection the combined peptides demonstrate in preliminary work, this proposal has potential to transform cardiac arrest care.