Fig. 8. Epithelial-derived laminin α5 is required for the hair cycle regulation.

a Immunohistochemical examination of laminins α5 (red) and β1 (green) in the dorsal telogen HFs of control (K5Cre⁺;Lama5^fl/+) and K5Cre⁺;Lama5^fl/− mice. Magnified images of the dotted squares are shown (right panels). Open arrowheads indicate interface basement membranes (BMs). Arrows indicate hook BMs. b Immunohistochemical examination of laminin α5 (green) and integrins α6 (red) and β1 (white) in the dorsal telogen HFs of control (K5Cre⁺;Lama5^fl/+) and K5Cre⁺;Lama5^fl/− mice. Open arrowheads indicate interface BMs. Arrows indicate hook BMs. c Measurement of pigmented skin areas. Pigmented area, which is associated with the presence of anagen HFs, on the shaved dorsal skin was determined from binarized photos (right side of each panel) at various postnatal days (P). d Comparison of hair cycle patterns between control and mutant mice. Ratio of pigmented area represents the ratio of anagen HFs. Four litter pairs were examined. One pair of littermates was examined from P21 to P47 and another pair from P48. A horizontal bar indicates the period for detailed hair cycle pattern analysis shown in (e). e Precocious anagen entry and the formation of a travelling hair regeneration wave in K5Cre⁺;Lama5^fl/− mice. f Immunofluorescence labelling of pSMAD2 (green), perlecan (red) and DAPI counterstain (blue) in the neck and hip skin regions of control (K5Cre⁺;Lama5^fl/+) and K5Cre⁺;Lama5^fl/− mice. Magnified images of the dotted squares are shown (right panels). Open arrowheads indicate strong pSMAD2 signals in the HG region of K5Cre⁺;Lama5^fl/− mice. g Immunofluorescence labelling of laminin α5 (green), perlecan (red), lef1 (white) and DAPI counterstain (blue) in the dorsal telogen phase HFs (P84) of control (K5Cre⁺;Lama5^fl/+) and K5Cre⁺;Lama5^fl/− mice. Scale bars: 100 μm (a, f), 20 μm (b, g).