Unraveling the Synergistic Neuroprotective Mechanism of Natural Drug Candidates Targeting TRPV1 and TRPM8 on an Ischemic Stroke

The development of multitargeted drugs is urgent for ischemic stroke. TRPV1 and TRPM8 are important targets of ischemic stroke. Previous drug candidate screening has identified that muscone, l-borneol, and ferulic acid may target TRPV1 and TRPM8 for ischemic stroke. However, the mechanisms of these drug candidates on targets were ill-informed. Therefore, firstly, a tongue-tissue biosensor was constructed. It explored the activation or inhibition mechanisms of drug candidates targeting TRPV1 and TRPM8 in a near-physiological environment. It was found that muscone could specifically inhibit TRPM8 and selectively activate TRPV1, while l-borneol exhibited the opposite effect. It suggested a synergistic network between these two drug candidates. Furthermore, more selective protein biosensors were developed to delve deeper into the synergistic mechanisms. A strong synergistic effect of muscone and l-borneol was proved. Molecular docking revealed that the synergistic effect was caused by different action sites, respectively. Subsequently, the synergistic effect of muscone and l-borneol was further confirmed by hypoxic nerve injury models of Caenorhabditis elegans (C. elegans) and antithrombus and anti-ischemic models of zebrafish. Ultimately, through nontargeted metabolomics, it was found that muscone and l-borneol mainly regulated Ca²⁺ concentration and energy metabolism by pathways such as purine and amino acid metabolisms. In conclusion, this research identified critical targets and synergistic drug candidates for multitarget neuroprotection of ischemic stroke. In addition, it has systemically demonstrated the feasibility of the integration of tissue/protein biosensors and metabolomics for the research and development of multitarget drugs. Compared to other screening and validation methods for drugs and targets, the biosensors we developed not only achieved higher sensitivity and specificity in complex physiological environments, ensuring a wider detection range, but also greatly saved biological samples. Simultaneously, they could be extended to other complex systems, such as biomarker screening in clinical samples and exosomes isolated from stem cells.