FIGURE 2.

The SNP rs12529 increases AKR1C3 protein stability and airborne PM upregulates AKR1C3 in human skin explants. A) LC–MS analyses of supernatants from HaCaT-AKR1C3-KO keratinocytes transfected with pAKR1C3wt, pAKR1C3H5Q, pAKR1C3wt/pAKR1C3H5Q (50:50), or empty vector. After 24 h, cells were treated with PGD₂ (1 μM) for up to 24 h. Shown as mean ± SEM of n = 3 (left) and normalized to pAKR1C3wt/wt at 24 h (right). (B) AKR1C3 protein level of 24 h samples shown in (A). Representative blot of n = 3. (C) LC–MS quantification of 9α,11β-PGF₂ after 24 h depicted in (A) normalized to AKR1C3 protein level shown in B). Shown as mean ± SEM of n = 3. (D) Keratinocytes were either transfected with pAKR1C3wt or pAKR1C3H5Q. After 24 h, cells were treated with 10 μM cycloheximide for up to 48 h. Representative blot (left) and mean quantification ± SEM of n = 4 (right). (E) Six μg/cm² diesel exhaust particles (DEP) were topically applied to cultured human skin explants at days 1, 4, and 7. Skin samples were harvested after single, double, or triple DEP application for 3 days. Gene expression of AKR1C3 was analyzed by qPCR and normalized to 18 S rRNA level. *p ≤ 0.05.