Down-regulation of miR-155 after treatment with narrow-band UVB and methotrexate associates with apoptosis of keratinocytes in psoriasis
Wipasiri Soonthornchai,1 Pattarin Tangtanatakul,1 Jitlada Meephansan,2 Kriangsak Ruchusatsawat,3 Rangsima Reantragoon,1 Nattiya Hirankarn,1 Jongkonnee Wongpiyabovorn1
1 Center of Excellence in Immunology and Immune Mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
2 Division of Dermatology, Chulabhorn International College of Medicine, Thammasat University, Pathum Thani, Thailand
3 National Institute of Health, Department of Medical Sciences, Nontaburi, Thailand
Abstract
Background: Psoriasis is a chronic inflammatory skin disease arising from a complex interaction between genetics, epigenetics, the host’s immune system and the environment. Recent accumulated data revealed the dysregulation of various microRNAs (miRNAs) in several diseases including psoriasis.
Objective: We explored the functional role and regulation of hsa-miR-155-5p (miR-155) in an immortalized keratinocyte cell line (HaCaT), in relation to the pathogenesis and treatment of psoriasis.
Methods: miR-155 expression in normal skin and psoriatic skin lesion before and after treatment with methotrexate (MTX) and narrow-band ultraviolet B phototherapy (NB-UVB) were analyzed using quantitative reverse transcription PCR (qRT-PCR). Apoptotic activity, cell cycle and viable cells of miR-155 transfected HaCaT were measured using flow cytometry and MTS assay. Since, caspase-3 (CASP3) gene was predicted as a target gene of miR-155, the expression of CASP3 was detected in transfected HaCaT using western blot.
Results: We discovered that both MTX and NB-UVB significantly down-regulated miR-155 expression in psoriatic skin lesions. We also found that overexpression of miR-155 in HaCaT led to suppression of cell apoptosis and induced cell arrest at G0/G1 phase. Moreover, CASP3 expression was down-regulated in miR-155 transfected HaCaT.
Conclusion: This study demonstrates down-regulation of miR155 after treatment with MTX and NB-UVB in psoriatic skin lesion. miR155 plays significant role in apoptosis on HaCaT via CASP3. This finding provides a better understanding of the pathogenesis of psoriasis and might aid on developing the new monitoring tool or therapy for psoriasis in the future.
Key words: psoriasis, miR-155, methotrexate, NB-UVB, apoptosis