Effect of IQGAP3 silencing on HaCaT keratinocytes under normal conditions or inflammatory cytokine stimulation

Scaffold protein IQGAP3 mediates assembly of multiprotein complexes, orchestrating intracellular signaling pathways. Earlier we have found it to be overexpressed in lesional psoriatic skin. IQGAP3 is involved in cell proliferation and chemokine signaling that are key processes in psoriasis, so we decided to investigate the molecular basis of its role in psoriatic phenotype of keratinocytes. Transcriptome profiling of HaCaT keratinocytes allowed us to identify a wide range of psoriasis-associated pathways to be altered in IQGAP3-knockdown cells. NFkB signaling, EGFR signaling, p38/MAPK and ERK1/ERK2 activation, lipid metabolism and cytokine production as well as the response to the inflammatory cytokine stimulation were altered in the knockdown cells. Real-time analysis of cell growth revealed the alterations of proliferation and wound healing. The balance between proliferation and apoptosis of skin cells was altered, as well as the skin barrier functions and the production of IL-6 and IFNg. However, the diversity of the pathway alterations in the knockdown cells led us to the conclusion that IQGAP3 may not be the best target for the therapeutic inhibition to normalize the phenotype of keratinocytes in psoriasis. To investigate IQGAP3 roles in signal transduction and development of psoriatic phenotype of keratinocytes, we have knocked it down using shRNA and stimulated HaCaT_sh and HaCaT_ctrl lines with inflammatory cytokines (IL17, TNFa, IFNg)