Design, synthesis, and biological activity of TLR7-based compounds for chemotherapy-induced alopecia

Hair loss is a common dermatosis symptom and side-effect in cancer chemotherapeutics. Imiquimod application at mid and late telogen activated the hair follicle stem cells leading to premature hair cycle entry. Based on quinoline structure, a newly synthesized compound 6b displayed proliferation activity in vitro and in vivo through branch chain replacement and triazole ring cyclization. Toll-like receptors (TLRs) are also critical mediators of the immune system, and their activation is linked to various diseases. The present study aimed to expand new agonists within co-crystallization of TLR7 (PDB code: 5GMH); however, biological assays of NF-κB activity and NO-inhibition indicated that five selected compounds were TLR7 antagonists. Molecular docking indicated the binding mode differences: antagonists binding TLR7 in a different direction and interacting with adjacent TLR7 with difficulty in forming dimers.