Abstract: Objective To investigate the role of circular RNA （circRNA） in the occurrence of psoriasis. Methods Mesenchymal stem cells were isolated from skin lesions of 15 patients with psoriasis（psoriasis group） and skin tissues of 15 healthy human controls （control group） separately, and then subjected to cultivation. Flow cytometry and cell differentiation assay were performed to identify these mesenchymal stem cells. RNA sequencing was conducted to measure the of circRNA, and detailed bioinformatics analysis was performed. Then, 7 differentially expressed circRNAs were selected, and a circRNA-microRNA interaction network was established. In this network, 3 related microRNAs were selected and validated by real-time quantitative reverse transcription-polymerase chain reaction （qRT-PCR）. Statistical analysis was carried out by a two-sample t-test for comparison of qRT-PCR results between the psoriasis group and control group. Results As RNA sequencing showed, a total of 6 323 circRNAs were identified, and 3 227 out of these circRNAs were first reported in this study. Compared with the control group, 129 circRNAs were differentially expressed in the psoriasis group, including 123 up-regulated circRNAs and 6 down-regulated circRNAs. The predicted circRNA-microRNA interaction network showed that several psoriasis-related microRNAs were associated with the 7 circRNAs, such as miR-17-5p, miR-30e-5p, miR-142-3p/5p, miR-369-3p, miR-184, miR-4490, miR-654-3p and miR-423-5p. qRT-PCR also confirmed that the 7 differentially expressed circRNAs were up-regulated in the psoriasis group. Compared with the control group, the of the 3 selected microRNAs significantly decreased in the psoriasis group （t = 3.993, 3.217, 2.918, respectively, all P < 0.05）. Conclusion There is aberrant of circular RNAs in the mesenchymal stem cells from psoriatic skin lesions, which may take part in the occurrence of psoriasis.

Key words: Psoriasis, Mesenchymal stem cells, Circular RNA