Transforming growth factor-beta receptor type I and type II expression during murine hair follicle development and cycling

[摘要] Although the TGF-beta family of growth factors probably regulates skin and hair follicle development, its exact role is still quite ill-defined. Here, we characterize the correlative expression pattern of the interdependent high affinity receptor proteins for TGF-beta 1 and TGF-beta 3, TGF-beta receptor type I (TGF-beta RI) and TGF-beta receptor type II (TGF-beta RII), during hair follicle development and cycling in C57BL/6 mice. During neonatal follicle development, TGF-beta RII immunoreactivity is confined to epithelial cells. Focal epidermal TGF-beta RII expression is seen even before actual hair placode formation. In contrast to the TGF-beta RII immunoreactivity in the outer root sheath, precortical hair matrix and inner root sheath cells were TGF-beta RII negative during hair bulb morphogenesis. TGF-beta RI (Alk-5) immunoreactivity largely overlapped the TGF-beta RII expression pattern, but was more wide-spread, During hair follicle cycling in adolescent mice, TGF-beta RII immunoreactivity was restricted to follicles, and was strikingly hair cycle dependent (maximal immunoreactivity: anagen VI and early catagen). Again, TGF-beta RI (Alk-5) immunoreactivity co-localized with TGF-beta RII immunoreactivity, but was more extensive. Reverse transcriptase polymerase chain reaction analysis of TGF-beta RII mRNA confirmed peak transcript levels in back skin with most hair follicles in the anagen VI-catagen transformation. mRNA levels of TGF-beta RI (Alk-5) did not vary significantly during the hair cycle, whereas those of TGF-beta RI (threonine-serine kinase 7 L) declined during early anagen, and were maximal during the anagen-catagen transition. This provides a basis for defining the choreography of TGF-beta-related signalling during hair follicle morphogenesis and cycling, introduces intraepidermal TGF-beta RII immunoreactivity as a marker for imminent follicle development, and supports the concept that both TGF-beta RII and TGF-beta RI stimulation is involved in, but not restricted to, the control of catagen induction.

[发布日期] 1997-10-01

[关键词] Alk-5;development;hair growth;Tsk 7