Figure 1. HFSCs downregulate TLR2 in response to stress like a high-fat diet and aging.

A. Dysregulated pathways in old vs young mouse HFSCs. The top pathways are labeled red.

B. Representative confocal images of telogen hair follicles from young and old mice immunostained for TLR2 and CD34 demonstrate decreased TLR2 intensity in HFSC (CD34-positive) of old mice. Scale bars are 50 μm. The middle and right panels show a magnified view of the boxed area. Scale bars are 20 μm.

C. Quantification of TLR2 fluorescent intensity in images from B showing significantly lower TLR2 expression in HFSCs from the old mice. N =6 for each group.

D. GEO2R analysis of published RNA data from sorted follicle populations in the 2nd telogen to anagen transition demonstrates the increased level of TLR2 mRNA accompanied by the activation of TLRs signaling downstream.

E. Representative confocal images showing TLR2 expression in hair follicles from mice fed with a normal diet (ND) or high-fat diet (HFD). CD34 is an HFSC marker. Scale bars are 50 μm. Magnified images demonstrate decreased TLR2 intensity in HFSC (CD34-positive) of mice after HFD. Scale bars are 20 μm.

F. Quantification of TLR2 fluorescent intensity in images from E showing significantly lower TLR2 expression in HFSCs from HFD-fed mice. N = 7 and 6 for ND and HFD groups respectively. AU, arbitrary unit.

G. TLR2 mRNA expression in HFSCs from mice fed with ND or HFD for 4 days or 3 months. Data regenerated from published RNA sequencing dataset GSE131958. N = 3 for each group.

All bar graphs are mean ± s.e.m. Non-parametric Mann-Whitney test (C, G) or unpaired two-tailed t-test (F) was used to determine statistical difference.