PTD-DBM

A synthetic fusion peptide pairing a cell-penetrating protein transduction domain with the Dishevelled-binding motif of CXXC5, studied topically in mice for hair regrowth and wound healing via Wnt/beta-catenin pathway activation.

Also referenced as: PTD-DBM peptide, Protein Transduction Domain-Dishevelled Binding Motif, Protein Transduction Domain-Dvl Binding Motif

Also appears in: Dermal

What is PTD-DBM?

PTD-DBM is a synthetic fusion peptide named for its two halves: a protein transduction domain (PTD), a short cell-penetrating sequence whose only job is to carry cargo across membranes, joined by a flexible linker to the Dishevelled-binding motif (DBM), the stretch of CXXC-type zinc finger protein 5 (CXXC5) that docks onto Dishevelled. The construct works as a decoy — it occupies the site on Dishevelled that CXXC5 would otherwise bind, lifting that brake off Wnt/β-catenin signaling. It was built as a laboratory tool at Yonsei University in Seoul, and it reached the research-compound market after a 2017 mouse hair-regrowth paper circulated widely in hair-loss communities. Because every published in vivo experiment applied it to skin, it is sold almost exclusively as a topical rather than as an injectable vial.

How it works

Wnt/β-catenin signaling governs hair follicle development and entry into the anagen growth phase. CXXC5 is a negative-feedback regulator of that pathway, and PTD-DBM is designed to displace it:

• CXXC5 is the brake being released — CXXC5 binds Dishevelled and suppresses Wnt/β-catenin signaling; Cxxc5-knockout mice show accelerated hair regrowth, and CXXC5 is upregulated in miniaturized hair follicles and arrector pili muscles of human balding scalp (Lee et al., J Invest Dermatol, 2017;137(11):2260-2269)
• The DBM half competes for the Dishevelled PDZ pocket — Dishevelled’s PDZ domain is the docking surface for CXXC5; a 1.76 Å crystal structure of the mouse Dishevelled-1 PDZ domain, combined with modeling against NMR and X-ray data, mapped that interface specifically to support inhibitor design (Lee et al., Biochem Biophys Res Commun, 2017;485(3):584-590)
• The PTD half is delivery, not signal — the published peptide is a transduction domain plus linker plus the binding motif, with a FITC-conjugated lysine appended for visualization; the transduction domain contributes no pathway activity of its own (Lee et al., J Exp Med, 2015;212(7):1061-1080)
• The downstream readout is β-catenin stabilization — in human dermal fibroblasts treated at 2-10 µM, PTD-DBM raised β-catenin, α-smooth muscle actin, and collagen I in a concentration-dependent manner and increased endothelin-1 at both mRNA and protein level, while leaving the canonical Wnt targets c-Myc and cyclin D1 unaffected — a narrower transcriptional footprint than full pathway agonism (Lee et al., J Exp Med, 2015)

Research status

PTD-DBM is preclinical. Every in vivo efficacy result published to date comes from mouse skin, and every experimental paper involving the peptide traces to Yonsei University in Seoul — the in vivo hair and wound work to Kang-Yell Choi’s laboratory, and the supporting structural work to a separate Yonsei biochemistry group.

• Wound healing (2015). Cxxc5-knockout mice showed accelerated cutaneous wound healing with increased keratin 14 and collagen synthesis, and co-treating wounds with PTD-DBM and valproic acid — described in the paper as a GSK-3β inhibitor that activates Wnt/β-catenin by a separate mechanism — accelerated healing synergistically (Lee et al., J Exp Med, 2015;212(7):1061-1080)
• Hair regrowth (2017), the foundational paper. Disrupting the CXXC5–Dishevelled interaction with the competitor peptide activated Wnt/β-catenin signaling and accelerated both hair regrowth and wound-induced hair follicle neogenesis in mice (Lee et al., J Invest Dermatol, 2017;137(11):2260-2269). The journal ran a same-issue commentary from an independent dermatology group at Johns Hopkins, which framed the result as a contribution to understanding negative regulation of WNT signaling rather than as a demonstrated therapy (Kim and Garza, J Invest Dermatol, 2017;137(11):2248-2250)
• Androgenetic alopecia models (2023), with a partial failure. CXXC5 was placed downstream of DHT and prostaglandin D2. Topical PTD-DBM reversed PGD2-driven suppression of hair regrowth and neogenesis, but in the DHT arm it did not fully restore β-catenin, and the small molecule KY19382 was the only agent tested that completely restored β-catenin and completely improved vibrissa follicle elongation — which the authors read as evidence that DHT-driven loss requires simultaneous inhibition of both CXXC5 and GSK-3β (Ryu et al., Cells, 2023;12(4):555)
• Scar-attenuating patch (2023). PTD-DBM and valproic acid loaded into a pyrogallol-functionalized hyaluronic acid patch reduced scar formation in mouse wounds, suppressing α-smooth muscle actin while inducing stem-cell markers and collagen III (Lee et al., Adv Healthc Mater, 2023;12(18):e2203094)

The originating laboratory’s later work has moved away from the peptide toward small-molecule CXXC5–Dishevelled inhibitors, notably KY19382, an indirubin-3’-monoxime analogue that blocks both the CXXC5–Dishevelled interaction and GSK-3β (Ryu et al., Br J Pharmacol, 2021;178(12):2533-2546). That shift is itself a signal about the peptide’s developability.

No human clinical trials of PTD-DBM are registered on ClinicalTrials.gov, no human efficacy or pharmacokinetic data has been published, and no approved drug product contains it.

Common dosage forms

Because all published in vivo work is topical, PTD-DBM appears in the research market in topical formats rather than the injectable vials typical of the category: lyophilized powder for reconstitution into a carrier solution, pre-mixed solutions and serums, and small “booster” vials intended for scalp application. Combination products are common — most often paired with methyl vanillate, and in some listings with valproic acid, mirroring the combination arms used in the mouse studies.

Published mouse experiments applied the peptide across a wide concentration range: 100 µM daily on wounds in the 2015 wound-healing study, and 10 mM solutions on depilated or wounded dorsal skin in the hair-regrowth and neogenesis work, with cell-culture work at 2-10 µM. There is no pharmacopeial monograph or reference standard for this peptide, and formats vary substantially between suppliers.

Key considerations

• No approval, no registered trial, no human safety data — PTD-DBM has no FDA approval and no study registered on ClinicalTrials.gov. Published safety observation is limited to short mouse experiments; no human pharmacokinetic, dermal irritation, or systemic exposure data exists. Topical products marketed under cosmetic rules were brought to market on preclinical data and have not been reviewed by the FDA.
• Single-laboratory evidence base with a disclosed commercial interest — all in vivo hair and wound results trace to the Choi laboratory at Yonsei University, and the senior author’s own conflict-of-interest statements disclose that he is CEO of the company holding the license to the CXXC5–Dishevelled program (CK Biotech, later CK Regeon). Independent experimental replication of the hair phenotype has not been published; independent mentions so far are reviews and commentary, not new data.
• “PTD-DBM” names an architecture, not a standardized molecule — the literature describes the construct by its parts (transduction domain, linker, binding motif, fluorescent tag for imaging) rather than publishing one canonical sequence in the abstract-level record. Two suppliers’ “PTD-DBM” are not necessarily the same peptide, and there is no reference standard to test a sample against.
• The assays are mouse-specific — synchronized mouse hair cycling and wound-induced follicle neogenesis, which is robust in mice and far more limited in adult humans, underpin every positive result. No ex vivo human hair follicle or human dermal papilla efficacy data has been published for the peptide itself.
• Naming confusion is common — PTD-DBM is frequently conflated with KY19382, the small-molecule successor from the same lab and a different chemical class entirely. Separately, “DBM” denotes demineralized bone matrix in orthopedic literature, and the broader CXXC5 literature spans bone, wound, and hair biology — the Dishevelled PDZ structural work, for instance, was motivated by osteoporosis rather than hair loss.