Objective       To investigate the expression and function of Frizzled4

a receptor of Wnt proteins

during mouse hair follicle cycle.       Methods       Q-PCR

Western blotting and immunostaining were used to detect the mRNA and protein expres

sion of Frizzled4 in mouse hair follicle cycle at 5 time points: the first day after birth (P1d)

P3d

P8d

P16d

and P21d. Immunostaining was used to detect the protein expression of Frizzled4 in mouse skin epithelium cell line JB6 cl30-7b. MTT assay was used to detect proliferation of JB6 cl30-7b cells after treatment of anti-Frizzled4 antibody.       Results       At P1d

mRNA and protein of Frizzled4 were both detected in mouse skin and Frizzled4 was expressed in the Bulge

out root sheath (ORS) and lateral hair bulb. At P3d

protein expression of Frizzled4 was up-regulated in the Bulge

ORS

inner root sheath (IRS)

precortex and part of lateral hair bulb. And at middle anagen (P8d)

protein of Frizzled4 was expressed at the highest level in the Bulge

ORS

IRS and pre-cortex. And then at catagen (P16d)

expression of Frizzled4 was decreased significantly （

P

0.05）and mainly located in the Bulge while little in ORS and IRS. When hair follicles were at telegen

expression of Frizzled4 reduced to the lowest level （

P

0.05）and was restricted in the Bulge. Frizzled4 was expressed on cell membranes of JB6 cl30-7b cells. After treatment of 10 μg/mL anti-Frizzled4 antibody

OD values decreased significantly compared with that of controls（

P

0.05）. After treatment of 20 μg/mL anti-Frizzled4 antibody

OD values dropped to the lowest level（

P

0.05）.       Conclusion       Expression of Frizzled4 is specific and spatiotemporal during hair follicle cycle. It is significantly high at anagen

reduces at catagen and maintains at a lowest level at telegen. Antagonism of Frizzled4 inhibits significantly proliferation of keratinocytes. These results indicate that the expression of Frizzled4 is associated with the growth and differentiation of hair follicles.