Figure 2

Primary sebocytes isolated from scalp sebaceous glands can differentiate in vitro and produce sebum-characteristic lipids. (a) SSG3 expresses PPARγ but not Keratin 8 in contrast to SEB-1. (b-c) Real-time PCR shows that PPARγ is equally expressed in SEB-1 and SSG3 whereas FADS2 is more highly expressed in SSG3 cells than SEB-1. RNA from SEB-1 and SSG3 derived from the scalp explant at passage 3 were normalized to GAPDH expression. Data shown represent three independent experiments each performed in triplicate (mean +/−SD, n=3). * p-value <0.05 (unpaired two-tailed student’s t test). (d) Cells were cultivated for 48 h with or without 0.1 mM of linoleic acid (LA). Differentiation through LA activation is followed by an increase in PPARγ expression in SSG3 cells. * p-value <0.05 paired two-tailed student’s t test). (e) 24 h and 48 h of LA treatment induce a significant increase of FADS2 expression in SSG3 cells. * p-value <0.05 (paired two-tailed student’s t test). (f) The Δ6 desaturase/FADS2 catalyzes the transformation of palmitic acid into sapienic acid. (g) Lipid analysis showing the percentage of Δ9 and Δ6 in the pellet of NIKS and SSG3 and the ratio Δ6/Δ9. (h) The sapienic acid (*) can be detected in SSG3 as in vivo sebum, whereas in NIKS, the palmitoleic acid (**) is the abundant lipid detected.