Variances in the Expression Profile of DUSP1-7 and miRNAs Regulating their Expression in the HaCat Line under LPS and Cyclosporine A

Abstract

Introduction: Cyclosporin A (CsA) treats moderate to severe psoriasis vulgaris. Psoriasis is a chronic inflammatory disease in which hyperproliferation of keratinocytes occurs. One of the most relevant signaling cascades in the development of psoriasis is the mitogen-activated protein kinase (MAPK) signaling pathway. It has been observed that dual-specificity phosphatases (DUSPs) dephosphorylate signaling molecules, such as MAPKs.

Aims: This study aims to determine changes in the expression pattern of Dual Activity Protein Phosphatase (DUSP1-7) and micro RNAs (miRNAs), potentially regulating their expression in the human adult, low-calcium, high-temperature keratinocytes cell line (HaCaT) cultures exposed to lipopolysaccharide A (LPS)-induced inflammation, followed by CsA.

Methods: HaCaT cell line was exposed for 8 hours to 1 μg/mL LPS and then to 100 ng/mL CsA for 2, 8, and 24 hours compared to cultures not exposed to LPS and the drug. The molecular analysis included determining the DUSP1-7 expression and the miRNAs potentially regulating it using an expression microarray technique. An enzyme-linked immunosorbent assay (ELISA) was also performed to assess the concentration of DUSP1-7 in the culture medium. Statistical evaluation was performed assuming a statistical significance threshold (p) of < 0.05.

Results: Statistically significant differences were found in the expression of DUSP1-7 mRNAs and the miRNAs that regulate their expression. The most significant changes in expression were observed for DUSP1 and DUSP5, with the differences being most pronounced during the eighthour incubation period of the cells, with the drug predictive analysis showing that miR-34 potentially regulates the expression of DUSP1-4,7, miR-1275: DUSP2, mir-3188: DUSP4, miR-382: DUSP4, miR-27a and miR-27b: DUSP5,6 and miR-16: DUSP7. No expression of DUSP1-7 was demonstrated at the protein level in CsA-exposed cultures.

Conclusion: Our evaluation of the efficacy of CsA therapy on an in vitro model of HaCaT indicates that treatment with this drug is effective, resulting in changes in the expression of DUSP1-7 and, potentially, the miRNAs that regulate their expression. We also confirmed that the different expression pattern of mRNA and protein encoded by a given transcript is not only due to the regulatory role of miRNAs but also the lack of synchronization between transcription and translation processes.

Keywords: Dual-specificity phosphatase; ELISA; HaCaT; LPS; cyclosporine A; miRNA; microarray; molecular marker.