Remote Activation of Spinal TRPV1 by Magnetic Nanocubes Confers Cardioprotection Against Myocardial Ischemia-Reperfusion Injury.

The heat-sensitive transient receptor potential vanilloid 1 (TRPV1), which is highly expressed on cardiac sensory neurons, reportedly plays a crucial role in transmitting nociceptive signals from the heart to the spinal cord during myocardial ischemia and reperfusion. Here, iron oxide nanocubes (FeNCs) are developed that are conjugated with an antibody against the extracellular portion of TRPV1, and they are named FeNCs-TRPV1. In F11 cell line and primary dorsal root ganglion neurons, FeNCs-TRPV1 specifically activate TRPV1 channels and trigger Ca(2+) influx through magnetothermal effect under an alternating current magnetic field (ACMF). Intraspinally injected FeNCs-TRPV1 induced TRPV1 desensitization in rats exposed to repetitive and transient ACMF before ischemia, resulting in the inhibition of TRPV1-mediated Ca(2+) signaling and neuropeptide release in the spinal cord during myocardial ischemia and reperfusion. Consequently, FeNCs-TRPV1 reduce cardiac injury and ventricular arrhythmia, enhance the activity of prosurvival kinases, and inhibit myocardial cell apoptosis. These findings suggest that magnetic nanomaterials-mediated remote regulation of spinal TRPV1 can be a novel non-invasive neuromodulation therapy for the treatment of myocardial ischemia-reperfusion (IR) injury.