Unlocking the potential: m6A-RNA methylation in severe epidermolysis bullosa simplex.

Abstract

Epidermolysis bullosa simplex (EBS) is a rare genetic disorder, resulting from mutations in keratin 5 and keratin 14 (KRT14), and is characterised by skin fragility, herpetiform blistering, and the development of confluent palmoplantar keratoderma and nail dystrophy. Inflammation, pain and itch are the most common complications of severe EBS. However, pathophysiological mechanisms remain poorly characterised at a molecular level. Recently, RNA N6-methyladenosine (m6A) nucleotide modification has been implicated in several cutaneous physiological processes, including epidermal differentiation, inflammation, adaptive immune responses, host-pathogen interactions, wound healing and tissue repair. Nevertheless, the role of m6A in EBS has yet to be defined. In this pilot study, we investigated the gene expression of key regulators of m6A, such as writers Methyltransferase-like 3 and 4 (METTL3 and METTL14), readers YTH domain-containing proteins (YTHDC1, YTHDC2, YTHDC3) and YTH domain-containing family proteins ( YTHDF1 and YTHDF2) and erasers fat mass and obesity-associated (FTO) and alkB homolog 5 (ALKBH5), as well as total RNA m6A levels in the EB keratinocites cell line (KEB-7) derived from a patient with severe EBS, carrying the KRT14 R125P mutation. NEB-1 cells, derived from a healthy donor, were employed as controls. RNAseq and quantitative RT-PCR demonstrated up-regulation of the writer METTL14, while FTO was down-regulated. Moreover, the total RNA m6A colorimetric assay reported higher levels of m6A in severe EBS cells (KEB-7). Additionally, increased expression of the reader of YTHDC1 suggests a dysregulation of downstream pathways. These findings suggest a potential role for m6A in determining complications in severe EBS; however, its role and effects need to be fully elucidated.