2. Academic Validation
  3. Extended therapeutic window of a novel peptide inhibitor of TRPM2 channels following focal cerebral ischemia

Extended therapeutic window of a novel peptide inhibitor of TRPM2 channels following focal cerebral ischemia

  • Exp Neurol. 2016 Sep;283(Pt A):151-6. doi: 10.1016/j.expneurol.2016.06.015.
Takeru Shimizu 1,  Robert M Dietz 2,  Ivelisse Cruz-Torres 3,  Frank Strnad 1,  Ana K Garske 1,  Myriam Moreno 1,  Venugopal R Venna 4,  Nidia Quillinan 1,  Paco S Herson 5
Affiliations

Affiliations

  • 1 Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA; Neuronal Injury Program, University of Colorado School of Medicine, Aurora, CO, USA.
  • 2 Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA; Neuronal Injury Program, University of Colorado School of Medicine, Aurora, CO, USA.
  • 3 Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA; Neuronal Injury Program, University of Colorado School of Medicine, Aurora, CO, USA.
  • 4 Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA.
  • 5 Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA; Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, USA; Neuronal Injury Program, University of Colorado School of Medicine, Aurora, CO, USA. Electronic address: paco.herson@ucdenver.edu.
PMID: 27317297 DOI: 10.1016/j.expneurol.2016.06.015
Abstract

Introduction: TRPM2 channels have been suggested to play a role in ischemic neuronal injury, specifically in males. A major hindrance to TRPM2 research has been the lack of specific TRPM2 inhibitors. The current study characterized the specificity and neuroprotective efficacy of a novel TRPM2 inhibitor.

Methods: Fluorescent calcium imaging (Fluo5F) was used to determine inhibitor efficacy of the TRPM2 peptide inhibitor (tat-M2NX) in HEK293 cells stably expressing hTRPM2. Adult (2-3months) and aged (18-20months) mice were subjected to 60min middle cerebral artery occlusion (MCAO) and injected with tat-M2NX, control scrambled peptide (tat-SCR) or clotrimazole (CTZ) either 20min prior or 3h after reperfusion. Infarct size was assessed using TTC staining.

Results: TRPM2 inhibition by tat-M2NX was observed by decreased CA(2+) influx following H2O2 exposure human TRPM2 expressing cells. Male mice pre-treated with tat-M2NX had smaller infarct volume compared to tat-SCR. No effect of tat-M2NX on infarct size was observed in female mice. Importantly, male TRPM2(-/-) mice were not further protected by tat-M2NX, demonstrating selectivity of tat-M2NX. Administration of tat-M2NX 3h after reperfusion provided significant protection to males when analyzed at 24h or 4days after MCAO. Finally, we observed that tat-M2NX reduced ischemic injury in aged male mice.

Conclusions: These data demonstrate the development of a new peptide inhibitor of TRPM2 channels that provides protection from ischemic stroke in young adult and aged male Animals with a clinically relevant therapeutic window.

Keywords

Aging; Cerebral ischemia; Experimental stroke; Sex; TRPM2 channel.

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