Targeted Expression of Human Vitamin D Receptor in the Skin Promotes the Initiation of the Postnatal Hair Follicle Cycle and Rescues Alopecia in Vitamin D Receptor Null Mice
vitamin D receptor VDR hair follicle cycle alopecia keratin 14 promoter transgenic mice anagen epidermis outer root sheath hair shaft skin histology immunohistochemical analyses vitamin D receptor VDR hair cycle hair loss keratin promoter genetically modified mice growth phase skin layer hair follicle sheath hair structure skin tissue study immunostaining
TLDR Vitamin D receptor is crucial for starting hair growth after birth.
The study demonstrated that the vitamin D receptor (VDR) is essential for initiating the postnatal hair follicle cycle in mice. Researchers used the human keratin 14 promoter to express human VDR in the skin of transgenic mice and created VDR null mice expressing the human VDR transgene. While VDR null mice developed alopecia, the VDR null/human VDR mice maintained a normal hair coat and had hair shaft and skin histology similar to wild-type mice. Immunohistochemical analyses showed high expression of human VDR in the basal layer of the epidermis and outer root sheath of hair follicles. When anagen was induced, VDR null mice failed to initiate the hair cycle, whereas VDR null/human VDR mice showed normal anagen follicle formation. The study provided direct evidence that VDR is required for the initiation of the postnatal hair follicular cycle.
