Transcriptional factor KLF4 inhibits epithelial to mesenchymal transition by attenuating TGFβ pathway in human retinal pigment epithelial cells

Abstract

Purpose: Transcription factor KLF4 is one of four genes used for reprogramming induced stem cells (iPS) and has been shown to regulate cell proliferation and differentiation. Retinal pigment epithelial cells can be transformed into fibroblastic and myofibroblastic phenotypes via epithelial to mesenchymal transition (EMT) lead to the proliferative vitreoretinopathy (PVR), the major cause of surgical failure following retinal detachment and ocular trauma. We hypothesize that KLF4 regulates EMT in retinal pigment epithelial cells by attenuating the TGFβ pathway.

Methods: ARPE19 cells were transduced with KLF4 doxycycline-inducible lentiviral vector and maintained in DMEM supplemented with 10% FBS. To examine the effect of KLF4 on EMT marker gene expression, we treated KLF4 expressing and control ARPE19 cells with different doses of TGFβ1 (0, 3, 6ng/ml) for 48 hours following 24h serum-starvation. EMT marker genes were detected by Western blot and immunostaining following treatment with TGFβ.

Results: KLF4 expression upregulates epithelial cell marker E cadherin and downregulates mesenchymal cell markers β-catenin and N-cadherin compared to the control cells. Furthermore, KLF4 expression downregulates phospho-SMAD2 and phospho-SMAD3, and thus attenuates TGFβ signaling pathway.

Conclusions: The KLF4 transcription factor inhibits induced EMT marker gene expression in ARPE19 cells by attenuating the TGFβ pathway.