FOXO1 regulates wound‐healing responses in human gingival fibroblasts
Leticia Rojas, Nicolás Tobar, Javier Espinoza, Susana Ríos, Constanza Martínez, Jorge Martínez, Dana T. Graves, Patricio C. Smith - Periodontics
Abstract
Background and objective
Forkhead box‐O 1 (FOXO1) is a transcription factor actively involved in oral wound healing at the epithelial barrier. However, less is known regarding the role of FOXO1 during the tissue repair response in the connective tissue compartment. This study explored the involvement of FOXO1 in the modulation of fibroblast activity related to wound healing.
Methods
Primary cultures of human gingival fibroblasts were obtained from four healthy young donors. Myofibroblastic differentiation, collagen gel contraction, cell migration, cell spreading, and integrin activation were evaluated in the presence or absence of a FOXO1 inhibitor (AS1842856). Variations in mRNA and proteins of interest were evaluated through qRT‐PCR and western blot, respectively. Distribution of actin, α‐smooth muscle actin, and β1 integrin was evaluated using immunofluorescence. FOXO1 and TGF‐β1 expression in gingival wound healing was assessed by immunohistochemistry in gingival wounds performed in C57BL/6 mice. Images were analyzed using ImageJ/Fiji. ANOVA or Kruskal‐Wallis test followed by Tukey's or Dunn's post‐hoc test was performed. All data are expressed as mean ± SD. p < .05 was considered statistically significant.
Results
FOXO1 inhibition caused a decrease in the expression of the myofibroblastic marker α‐SMA along with a reduction in fibronectin, type I collagen, TGF‐β1, and β1 integrin mRNA level. The FOXO1 inhibitor also caused decreases in cell migration, cell spreading, collagen gel contraction, and β1 integrin activation. FOXO1 and TGF‐β1 were prominently expressed in gingival wounds in fibroblastic cells located at the wound bed.
Conclusion
The present study indicates that FOXO1 plays an important role in the modulation of several wound‐healing functions in gingival fibroblast. Moreover, our findings reveal an important regulatory role for FOXO1 on the differentiation of gingival myofibroblasts, the regulation of cell migration, and collagen contraction, all these functions being critical during tissue repair and fibrosis.