Differential induction of TLR2/c-Jun and NF-κB signaling pathway in human keratinocytes infected by Trichophyton rubrum and Microsporum gypseum

Abstract

Objective: To explore the activation of TLR2/c-Jun and NF-κB signaling pathway in human keratinocytes infected by different ecological classifications of dermatophytes. Methods: Total and phosphorylated p65, relb, IκB, and c-Jun in HaCaT cells were detected by immunoblotting following co-culture with either Trichophyton rubrum(T. rubrum) or Microsporum gypseum(M. gypseum) for 24 h. Immunoblotting was used to assess expression levels of TLR2, c-Jun, and phosphorylated c-Jun after co-culture of TLR2 deficient HaCaT cells (HaCaT TLR2-/- cells) with T. rubrum and M. gypseum for 24 h. Results: Co-culture of HaCaT cells with M. gypseum, but not T. rubrum, significantly increased the levels of phosphorylated c-Jun. However, neither T. rubrum nor M. gypseum induced significant changes in the total and phosphorylated p56, relb, and IκB in HaCaT cells. Following TLR2 knockout in HaCaT cells, the level of phosphorylated c-Jun decreased significantly in HaCaT TLR2-/- cells co-cultured with T. rubrum, but not M. gypseum. Conclusions: T. rubrum and M. gypseum can activate c-Jun signaling pathway through TLR2 in keratinocytes, without activation of NF-κB signaling pathway. TLR2, together with other receptors, may dominate the differential induction of c-Jun pathway in keratinocytes infected by T. rubrum and M. gypseum.

Keywords

• keratinocytes
• trichophyton rubrum
• microsporum gypseum
• tlr2
• c-jun signaling pathway