726 The Wnt-inhibitor Dkk4 is required for primary hair follicle induction and patterning

Androgenetic alopecia is a common form of pattern hair loss, characterized by miniaturized follicles (HFs) at the front and parietal scalp, while hairs on occipital scalp are preserved. Moreover, different sites human body exhibit distinct types patterns HFs. Understanding molecular basis this heterogeneity will help to design targeted treatment strategies. The Wnt signalling pathway its Dickkopf (Dkk) inhibitors have been suggested regulate HF induction patterning. We previously shown that Dkk4 specifically expressed in placodes during mouse skin development. To elucidate functions patterning, work, we generated Dkk4-knockout mice using CRISPR/Cas9. mutants showed disrupted patterning with an increase interplacodal distance. Surprisingly, lateral back completely lacked first wave In order address regional differences formation, Dkk4-EGFP knockin line, which recapitulated expression placodes. Our data revealed intra- Dkk4-EGFP, suggesting WNT-DKK axis underlies specificities Elucidating mechanisms shed light loss such as androgenetic alopecia.