The Wnt-Inhibitor Dkk4 Is Required for Primary Hair Follicle Induction and Patterning

The study "The Wnt-inhibitor Dkk4 is required for primary hair follicle induction and patterning" investigates the role of the Wnt signalling pathway and its Dickkopf (Dkk) inhibitors in hair follicle (HF) induction and patterning, with a focus on Dkk4. The researchers used CRISPR/Cas9 to create Dkk4-knockout mice and found that these mutants had disrupted HF patterning and an increased interplacodal distance. Notably, the first wave of HFs was completely absent in the lateral back skin of these mutants. A Dkk4-EGFP knockin mouse line was also generated to study regional differences in HF formation, revealing intra- and interplacodal differences in Dkk4-EGFP expression. These findings suggest a WNT-DKK axis underlies regional specificities in HF induction and patterning, which could provide insights into hair loss patterns such as in androgenetic alopecia.