Skin treatment with non-thermal plasma modulates the immune system through miR-223-3p and its target genes

Non-thermal plasma, a partially ionized gas, holds significant potential for clinical applications, including wound healing support, oral therapies, and anti-tumour treatments. While its applications shown promising outcomes, the underlying molecular mechanisms remain incompletely understood. We thus applied non-thermal plasma to mouse auricular skin and conducted non-coding RNA sequencing, as well as single-cell blood sequencing. In a time-series analysis (5 time points spanning 2 hours), we compared the expression of microRNAs in the plasma-treated left ears to the unexposed right ears of the same mice as well as to the ears of unexposed control mice. Our findings indicate specific effects in the treated ears for a set of five miRNAs: mmu-miR-144-5p, mmu-miR-144-3p, mmu-miR-142a-5p, mmu-miR-223-3p, and mmu-miR-451a. Interestingly, miR-223-3p also exhibited an increase over time in the right non-treated ear of the exposed mice, suggesting systemic effects. Notably, this miRNA, along with mmu-miR-142a-5p and mmu-miR-144-3p, regulates genes and pathways associated with wound healing and tissue regeneration (namely ErbB, FoxO, Hippo, and PI3K-Akt signalling). This co-regulation is particularly remarkable considering the significant seed dissimilarities among the miRNAs. Finally, single blood cell sequencing revealed the downregulation of 12 from 15 target genes in B-cells, Cd4+ and Cd8+ T-cells. Collectively, our data provide evidence for a systemic effect of non-thermal plasma. Single-cell peripheral blood mononuclear cells: Four C57BL/6 wild-type mice were anaesthetized. The two mice of the treatment group were irradiated with NTP for 10 minutes using anatmospheric pressure argon plasma jet. The other two mice belonging to the control group were equally anaesthetized but remained unexposed to non-thermal plasma. The blood of the four mice was collected after a period of 120 min from the vena cava.