Figure 1.

Histological evaluation of PGC-1α expression in human skin

(A) PGC-1α expression in human tissue microarray (TMA) evaluated by immunohistochemistry (IHC). Data are shown as mean + SEM from 4 sections. Positivity is scored as low, medium, and high.

(B) Representative set of human sections shown in A. B1 is a brain section, C1 is breast, and D1 is skin (in dotted box). The remaining sections follow the same order as in A, from left to right.

(C) Relationship between the mitochondrial marker NDUFA9 and PGC-1α in human TMA. Data are shown as mean ± SEM from 4 sections.

(D) PGC-1α expression in various human skin features and appendages, obtained from 4 to 9 donors. Data are shown as mean + SEM. Epidermal basal layer shows stronger positivity than suprabasal layers, ∗p < 0.05, paired Student’s t test. Positivity score is the same as explained in A.

(E) PGC-1α expression in epidermal basal layer and suprabasal layers. Data from each donor are matched with a solid line. N = 9 donors. ∗p < 0.05, paired Student’s t test.

(F) Upper panel: pictures of 200 μm skin regions with highest PGC-1α positivity for each donor, as acquired by IHC. Lower panel: PGC-1α expression in the basal layers from the 200 μm skin sections shown in the upper panel. ∗p < 0.05 (total positivity, high positivity, and medium positivity), unpaired Student’s t test. Positivity score is the same as in A.

(G) PGC-1α expression in skin basal layer from young (22–27 y.o.) and aged (66–74 y.o.) donors, where each dot represents a single human donor. ∗p < 0.05, unpaired Student’s t test. (H) NDUFA9 expression in skin basal layer from young (22–27 y.o.) and aged (66–74 y.o.) donors, where each dot represents a single human donor. ns: non-significant difference, unpaired Student’s t test.