Abstract DP268: Pharmacological Inhibition of Transient Receptor Potential Melastatin 7 Kinase Reduces Neonatal Hypoxic-Ischemic Brain Injury

Introduction: Neonatal hypoxic-ischemic brain injury (HIBI) is a leading global cause of perinatal neurological morbidity, with limited treatments. The ion channel-kinase Transient Receptor Potential Melastatin 7 (TRPM7) contributes to HIBI pathology. While TRPM7 channel activity has been widely studied, the role of its α-kinase domain remains unclear. We hypothesized that pharmacological inhibition of TRPM7 kinase (T7KI) would mitigate HIBI and improve both short- and long-term neurological outcomes in vivo. Methods: HIBI was induced in postnatal day 7 CD-1 mice by right common carotid artery ligation followed by 60 min of hypoxia. T7KI or vehicle was administered via intraperitoneal injection. Infarct volume was assessed histologically and morphologically, and neurological deficits were measured through neurobehavioral tests. Mechanistic studies (Western blotting, immunohistochemistry, confocal microscopy, electrophysiology) examined the drug’s mode of action, while pharmacokinetics defined its in vivo profile. Results: Compared with vehicle (Fig. 1, 42.99 ± 1.84%, n = 75), pre-HIBI administration of the T7KI at three doses significantly reduced infarct volume (1.0 mg/kg: 32.53 ± 2.18%, n = 32; 2.5 mg/kg: 26.22 ± 2.31%, n = 17; 5.0 mg/kg: 34.33 ± 2.75%, n = 21). Post-HIBI T7KI treatment applied up to 3 h (a more clinically relevant paradigm) also reduced infarction (1 h: 32.33 ± 3.66%, n = 23; 2 h: 33.43 ± 3.34%, n = 22; 3 h: 34.20 ± 4.35%, n = 12), defining a therapeutic window. The T7KI preserved cerebral morphology and body weight and improved short-term neurological function (vestibular, proprioceptive, motor, and muscle strength) at multiple time points within the first week after HIBI. Long-term outcomes at 4 weeks post-HIBI, including passive avoidance, rotarod, and novel object recognition, were also enhanced. Mechanistically, T7KI reduced neuronal apoptosis, suppressed TRPM7 expression upregulation, and mitigated microglial activation with NLRP3 inflammasome-mediated neuroinflammation. Further molecular assays (NF-κB, GSDMD-N), patch-clamp interrogation of TRPM7, and pharmacokinetic studies are underway to strengthen translational relevance. Conclusion: These findings identify the TRPM7 kinase domain as a therapeutic target in HIBI, with pharmacological inhibition providing significant neuroprotection and translational promise.