Identification of novel lead EphB1/2 tyrosine kinase inhibitors targeting peripheral neuropathic pain - PROJECT SUMMARY/ ABSTRACT. Chronic pain is a common debilitating condition that often leads to the prescription of escalating opioid doses and has created a nationwide severe crisis. In September 2022, the American Medical Association issued a report entitled Nation's opioid-related overdose and death epidemic continues to worsen, which stated more than 107,000 deaths were reported in the United States between December 2020 and December 2021. Therefore, there is an urgent need to develop novel, non-opioid, and non-addicting therapies that are effective in chronic pain management. Previous behavioral studies using the EphB1 knockout mice demonstrated a significant reversal of thermal hyperalgesia and mechanical allodynia induced by the experimental nerve damage followed by sciatic nerve constriction injury. Most recently, we revealed the synergism of three tetracyclines (Minocycline, Chlortetracycline, and Demeclocycline) family members that showed the competitive inhibitory profile along with ATP-binding catalytic domain of EphB1 tyrosine kinase and that this compound combination reversed thermal hyperalgesia and mechanical allodynia in various pain models. However, the IC50 for this approach is in the low micromolar range, requiring a near-maximal dose of all three antibiotics in combination. Our goal is pharmacologically to examine whether selective EphB1 tyrosine kinase inhibition is necessary and sufficient to reverse and/or block peripheral neuropathic pain development. Our overarching hypothesis is that our novel small molecules, not related to the tetracycline scaffold, will inhibit EphB1/2 tyrosine kinase signaling and will prove to be novel tools to investigate the mechanisms that either block or reverse peripheral and central nervous system neuronal activation and nerve damage, leading to decreased neuropathic pain-related biomarkers and behaviors associated with peripheral neuropathic pain. We have assembled a multi-disciplinary tour de force to navigate the potential of developing small molecules for chronic pain via the following aims: (1) Develop novel lead EphB1/2 tyrosine kinase inhibitors and (2) Elucidate the molecular mechanism of novel Eph81/2 tyrosine kinase inhibitor(s) in mitigating neuropathic pain in vivo. Successful completion of these aims will result in the development of a new generation of first-in-class potent EphB1 kinase inhibitors for the treatment of peripheral neuropathic pain.
