Fig. 1.

DS is associated with CBS and 3-MST overexpression in human dermal fibroblasts. (A) & (B): Protein expression of the H₂S-producing enzymes – CBS and 3-MST, and of the H₂S-catabolizing enzymes ETHE1, SQR, and TST, as quantified by immunoblotting. β-actin served as loading control for densitometry. (C): Representative images of the fluorescent signal of the H₂S-specific probe, AzMC along with (D) its quantification under baseline (untreated) conditions and following 24-h treatment with 3 μM AOAA. (E): Quantification of cellular H₂S levels using a second H₂S probe, P3. (F): Correlation between CBS and 3-MST enzyme expression patterns in DS. Each line and bar graph represents the mean ± SEM of n = 8 human euploid control fibroblasts and n = 8 DS fibroblasts. C1–C8 and D1-D8 corresponds to the specific donors listed in Table 1. Dotted connecting lines in the bar graphs indicate the same cell from a specific donor with/without AOAA treatment. **p ≤ 0.01 DSC indicates significant differences between untreated vs. CC untreated; ^##p ≤ 0.01 indicates significant differences between DSC + AOAA vs. DSC untreated. The immunoblot for 3-MST along with the corresponding loading control has been previously published [13] and is reused with permission and according to the Open Access Policy of the journal.