Linoleic Acid Induces Gap Closure of OKF6-Cells Through Hemichannel-Connexin Activity

Objectives: We evaluated the effect of linoleic acid on gap closure migration mediated by connexin hemichannels in human oral keratinocytes
Methods: Human keratinocytes cell line (OKF6) was used. The cells were maintained in regular culture conditions (37°C, 5%CO₂) with Keratinocytes-SFM medium supplemented with CaCl₂. Mediated mechanical stress (“scratch”), a wound healing assay was evaluated in the absence or presence of linoleic acid (LA, 100 µM). OKF6 cells in presence (2 – 24 h) of LA were used for PCR assays. Also, in presence of LA the connexin hemichannels activity was evaluated by dye uptake assay.
Results: In control conditions after 24 h of wound healing assays OKF cells had 25% of gap closure, but 24 h after linoleic acid (LA) treatment these cells had 65% of gap closure. Then, this increase in gap closure migration by LA was not evidenced in the presence of lanthanum (La³⁺, 200 µM), a connexin hemichannels inhibitor. At least, this cell type expresses Cx43 and Panx1. The expression of Cx43 (mRNA) increased after LA treatment (24 h). Panx1 expression did not change with LA treatment. Dye uptake assay showed activity of connexin-based hemichannels in the presence of LA. This activity was blocked in presence of La³⁺.
Conclusions: Linoleic acid increases the gap closure migration of human oral keratinocytes through an increase of connexin hemichannels activity.