Transforming Growth Factor-β1 Induces Concurrent Periostin and SLUG Expression in Normal Human Dermal Fibroblasts: Potential Implications for Extracellular Matrix Remodeling.

Background: Transforming growth factor beta 1 (TGF-β1) is a master regulator of fibrogenesis and extracellular matrix (ECM) remodeling. Among molecules involved in profibrotic signaling, periostin (POSTN) and the Snail family transcriptional repressor 2 (SLUG, SNAI2) have emerged as potential regulators of tissue remodeling and fibroblast activation. However, the temporal relationship between TGF-β1-induced expression of SLUG and periostin in human dermal fibroblasts remains poorly understood. Objectives: This study aimed to evaluate the effect of TGF-β1 stimulation on SNAI2/SLUG and POSTN/periostin expression dynamics in normal human dermal fibroblasts (NHDFs) and characterize their association with profibrotic responses. Methods: NHDFs were stimulated with recombinant human TGF-β1 (20 ng/mL) for 24, 48, and 72 h. SNAI2 and POSTN mRNA expression was quantified by RT-qPCR, intracellular SLUG protein levels were assessed by Western blotting, and periostin accumulation in the culture medium was measured by enzyme-linked immunosorbent assay (ELISA). The RT-qPCR and ELISA data were analyzed using two-way ANOVA with Bonferroni correction; because of the small number of replicates (n = 2), the Western blot data are presented descriptively. Results: TGF-β1 significantly increased POSTN mRNA expression after 24 and 48 h (both p < 0.001); at 72 h, POSTN mRNA levels remained numerically elevated relative to the control, although this difference did not reach statistical significance. Periostin accumulation in the culture medium increased progressively and was significantly higher than in the control group after 48 and 72 h (p < 0.001). In contrast, SNAI2/SLUG exhibited transient expression kinetics, with increased SNAI2 mRNA at 48 h (p < 0.05) and the highest SLUG protein levels also observed after 48 h of stimulation, followed by a decline at 72 h. Conclusions: TGF-β1 induced time-dependent changes in SNAI2/SLUG and POSTN/periostin expression in human dermal fibroblasts. As fibroblast activation and ECM remodeling were not directly assessed, the present conclusions are restricted to the expression changes in the two investigated molecules, whose concurrent yet temporally distinct regulation may indicate potential relevance in the fibroblast response to profibrotic signaling. Further studies are required to determine whether they participate in common regulatory mechanisms or independently contribute to fibrotic processes.