Targeting Expression of the Human Vitamin D Receptor to the Keratinocytes of Vitamin D Receptor Null Mice Prevents Alopecia

The study demonstrated that targeting the expression of the human vitamin D receptor (VDR) specifically to keratinocytes in VDR null mice prevented the development of alopecia. While VDR null mice typically developed several conditions, including alopecia, due to a lack of VDR, the introduction of a human VDR transgene under the control of the keratin 14 promoter in these mice successfully prevented hair loss. This was achieved by generating transgenic mice that expressed the human VDR, which, when mated with VDR null mice, resulted in offspring that did not develop alopecia. The study concluded that VDR expression in keratinocytes was necessary and sufficient to maintain a normal hair cycle, as evidenced by the enhanced proliferative response of hair follicle keratinocytes in these transgenic mice during anagen initiation.