The extracellular matrix fibulin 7 maintains epidermal stem cell heterogeneity during skin aging

A

Heatmap of ≥twofold upregulated or downregulated genes related to ECM from gene ontology analysis in Fig 4B and C. Scale reflects Z‐score.

B

Collagen IV immunostaining in tail sections of 3‐month‐old versus 2‐year‐old C57BL/6J mice. Dotted box regions are enlarged.

C

Quantification of Collagen IV basement membrane intensity per cell in 2‐year‐old mice normalized to 3‐month‐old mice in C57BL/6J mice (B). *P < 0.05. N = 4 mice per age group (biological replicates).

D

Laminin immunostaining in tail sections of 3‐month‐old versus 2‐year‐old C57BL/6J mice (left panels) and 1‐year‐old Fbln7 WT versus KO (right panels).

E, F

Quantification of laminin basement membrane intensity per cell in 2‐year‐old mice normalized to 3‐month‐old mice in C57BL/6J mice (E) or in Fbln7 KO mice normalized to WT mice (F). N = 6 per group for all mice. ns; not significant.

G

Collagen XVII immunostaining in tail sections of 3‐month‐old versus 2‐year‐old C57BL/6J mice (left panels) and 1‐year‐old Fbln7 WT versus KO (right panels).

H, I

Quantification of Collagen XVII intensity per cell in 2‐year‐old mice normalized to 3‐month‐old mice in C57BL/6J mice (H) or in Fbln7 KO mice normalized to WT mice (I). N = 7 (2–3 month‐old) and N = 10 (2‐year‐old) C57BL/6J mice; N = 6 per group in Fbln7 mice. **P < 0.01.

J

Shortlisted fibulin 7‐binding protein candidates (from Fig 5D and E) and their reported functions.

K

Solid‐phase binding assays using recombinant fibulin 7 as liquid phase and purified or recombinant ECM proteins as solid phase. X‐axis shows increasing doses of fibulin 7 (μg/well). Bovine serum albumin (BSA) was used as the control liquid phase and added in the same amounts as fibulin 7. Data are from four technical repeats in two independent experiments.

Figure EV5. Transcriptome of Fbln7 KO mice and fibulin 7‐binding assays indicate fibulin 7 mechanism of action through ECM regulation.