Spatial and temporal control of laminin-511 and -332 expressions during catagen

We recently reported that the basement membrane (BM) zone components laminin-511 and -332 precisely regulate hair growth spatially and temporally during the anagen stage of the hair cycle.

In this study, we examined the localization and roles of laminin-511 and -332 during catagen in mice.

Using tissue from C57BL/6 hair depilation model mice, we performed immunohistochemistry, in situ hybridization, western blotting, and quantitative reverse transcriptase polymerase chain reaction (QRT-PCR) studies.

Although the distribution of laminin-332 around the BM of lower hair follicles changed during catagen, its total expression was stable throughout catagen stages at both the mRNA and protein levels. In sharp contrast, in situ hybridization, western blotting, and QRT-PCR studies of laminin alpha 5 showed that laminin-511 expression was gradually downregulated. Moreover, while the injection of recombinant laminin-332 at anagen stage VI did not affect catagen progression, injection of a laminin-511-rich A549 cell conditioned media protein extract at anagen stage VI delayed progression of catagen.

These results indicated that downregulation of laminin-511 is important for hair regression.