Epithelial-mesenchymal interactions are a common process involved in early stages of morphogenesis of various organs and appendages like lung, kidney, hair follicles, tooth and nails. We used hair follicle as a model to study epithelial-mesenchymal interactions between the epidermal epithelial stem cells and dermal mesenchymal (dermal papilla) cells. From our previous gene expression analysis, many candidate genes are preferentially or specifically expressed in the dermal papilla (DP) cells during embryonic hair follicle morphogenesis. Among those, Leucine-rich repeat-containing protein 15 (Lrrc15) which is evolutionary conserved gene from C. elegans to human. We generated Lrrc15-LacZ knock-in chimeric mouse using CRISPR/Cas9 system to edit the genome and found that Lrrc15 starts to be expressed at E11.5 in the shoulder region. Lrrc15 was expressed in the whiskers, hair follicles among the head and trunk region, dorsal and ventral midlines, tongue, testis and nails in the later developmental stages. DP cells showed the expression signals in the early stages of hair follicle formation. We generated knock-out embryos by gene ablation approach showed some lethality around E12.5. The obtained phenotype showed some abnormalities like swollen transparent abdomen, incomplete closure of umbilicus and hemorrhage. Now, we are going to generate iCre-expressing mouse to target DP cells. As a next step, we will perform functional analysis for this gene. Our study aimed to establish DP-specific gene knockout system by generating DP-specific Cre-recombinase expressing transgenic mouse which will help in understanding the molecular bases of hair follicle formation and throw a light on developing hair regeneration therapy. |
