[Expression of microRNA-203 and P63 in human epidermal stem cells and keratinocytes].

Objective: To observe the changes in expression of microRNA-203 and P63 in human epidermal stem cells and KCs, and to investigate their effects and significance in the epidermal proliferation and differentiation.

Methods: (1) Five normal foreskin tissue specimens were collected from 5 patients by circumcision in Department of Urinary Surgery of the First Affiliated Hospital of Nanchang University from March to June in 2013. Then single cell suspension was obtained by separating epidermis with trypsin digestion method. The cells were divided into quick adherent cells and non-quick adherent cells by type IV collagen differential adherent method. The biological characteristics of cells were observed by inverted phase contrast microscope immediately after isolation and on post culture day (PCD) 3. The expression of CD29, keratin 19, keratin 1, and keratin 10 was identified by immunocytochemical staining. The expression of microRNA-203 and mRNA of P63 was determined by real-time fluorescent quantitative RT-PCR. The protein expression of P63 was determined by Western blotting. Data were processed with t test and Pearson correlation analysis.

Results: (1) Immediately after isolation, quick adherent cells were small, round, and dispersed uniformly. On PCD 3, the cells adhered firmly, and they grew in clones. Immediately after isolation, non-quick adherent cells appeared in different shapes and sizes, and dispersed unevenly. On PCD 3, the cells adhered precariously and did not show clonal growth. Quick adherent cells showed positive expression of CD29 and keratin 19, while non-quick adherent cells showed positive expression of keratin 1 and keratin 10. Quick adherent cells were identified as epidermal stem cells, and non-quick adherent cells were identified as KCs. (2)The expression level of microRNA-203 in epidermal stem cells (0.74 ± 0.20) was lower than that in KCs (3.66 ± 0.34, t =16.582, P <0.001). The mRNA expression level of P63 in epidermal stem cells (4. 16 ± 0.28) was higher than that in KCs (2.90 ± 0.39, t =5. 850, P =0.001). The protein expression level of P63 in epidermal stem cells (1.42 ± 0.05) was higher than that in KCs (0.73 ± 0.03, t =26.460, P <0. 001). (3) The expression level of microRNA-203 was in significantly negative correlation with the expression levels of mRNA and protein of P63 (with r values respectively - 0. 94 and -0.98 , P values below 0.05).

Conclusions: The expression levels of microRNA-203 and P63 in human epidermal stem cells and KCs were significantly different, which might be related to the different characteristics of proliferation and differentiation of the cells.