Development of the waixenicin A pharmacophore as a therapeutic intervention for neonatal hypoxic brain injury

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PROJECT SUMMARY/ABSTRACT Neonatal and perinatal hypoxic-ischemic brain injury (HIBI) is a major cause of acute mortality and chronic neurological morbidity in infants and children occuring in 2% of full-term infants and approaches 60% in premature infants. 20% to 50% of asphyxiated newborns die. Among the survivors, up to 25% show permanent neuropsychological handicaps such as cerebral palsy, generating lifetime costs to the US healthcare system at an estimated $11.5 billion USD. Therapeutic hypothermia was the first evidence-based neuroprotective therapy for neonates with hypoxic-ischemic encephalopathy (HIE) and has become the clinical standard of care (SOC). Despite reducing the combined rate of death and disability, therapeutic hypothermia has to be initaited within 6 hours of HIE, a very narrow diagnostic window. Neonates diagnosed within this time frame are treated with hypothermia for 3 days. Currently about half of hypothermia-treated HIE neonates experience adverse outcomes with personal and socioeconomic implications. Clearly, there is an unmet need for adequate therapeutic interventions against HIBI beyond current SOC. The divalent ion channel-kinase fusion protein TRPM7 controls critical cellular processes involved in ischemic events, including experimental HIBI, and is a biologically logical and highly promising target for drug development, particularly in light of the discovery of a highly selective and potent inhibitor, waixenicin A (WaixA). This provides an excellent starting point to develop semi-synthetic derivatives of WaixA with improved pharmacological properties towards therapeutic intervention in HIBI. Due to the established involvement of TRPM7 in hypoxia and WaixA effectiveness in HIBI, we hypothesize that semi- synthetic waixA derivatives protect against HIBI; that semi- synthetic analogs of WaixA covalently bind to TRPM7; and that, based on its excellent predicted blood-brain- barrier properties, optimized semi-synthetic analogs of waixA with improved physiochemical properties can serve as therapeutic leads against HIBI. To address the above, our interdisciplinary IGNITE team proposes to employ a combination of complementary approaches that rest on our respective core expertises and competencies: (1) Semi- synthetic optimization of WaixA analogs through proposed derivatization of isolated WaixA (R61); (2) Potency, selectivity, ADME and safety screens of semi-synthetic waixenicin derivatives in vitro through a Medicinal Chemistry Screening Cascade and selection of 3 WaixA analogs as lead compounds for in vivo work (R61); (3) Therapeutic validation of these 3 qualifying semi-synthetic waixenicin derivatives in an established mouse model of neonatal hypoxic-ischemic brain injury (HIBI) in vivo (R61 and R33) to ulitmately enable transition to Blueprint.