PTD-DBM

PTD-DBM (protein transduction domain conjugated to Dishevelled-binding motif; DBM derived from the Dishevelled-PDZ-binding C-terminus of CXXC5; molecular weight approximately 4 kDa as a synthetic conjugate) is a research-grade peptide developed at Yonsei University in South Korea by Kang-Yell Choi and colleagues as a tool for activating canonical Wnt signaling at the level of the Dishevelled scaffold. The canonical Wnt pathway is a developmental signaling system that drives stem cell self-renewal, tissue regeneration, and (importantly for hair) the anagen phase of the hair follicle cycle. CXXC5 is a negative regulator of canonical Wnt signaling that binds Dishevelled at a defined motif and prevents Dishevelled-mediated signal propagation; loss of CXXC5 in knockout mice produces enhanced Wnt signaling, accelerated hair cycle entry, and resistance to age-related hair thinning. The PTD-DBM peptide is designed to mimic the CXXC5 Dishevelled-binding motif and competitively displace endogenous CXXC5 from Dishevelled, releasing canonical Wnt signal flow. The PTD (HIV-Tat-derived protein transduction domain) enables cell membrane crossing of the otherwise impermeable peptide. Reported activities in rodent and human ex vivo hair follicle models include accelerated anagen induction, increased hair shaft length, and protection against chemotherapy-induced and androgenetic alopecia in rodent models. Topical formulation with the valproic acid co-treatment (KDC-MN-1348) has been explored as a synergistic Wnt-activating combination. The compound is research-grade and not approved by any regulatory authority; clinical translation through Yonsei University spin-out CXC5 has been in early stages. Reconstitution requires aqueous buffer with co-solvent for the peptide-PTD conjugate; topical delivery in the hair-follicle context is the principal route under investigation.