Incredible progress has been made in the past few year in the understanding of skin function and pathomechanisms underlying autosomal recessive congenital ichthyosis. From the first identification of mutations in TGM1 in 1995 by Huber and team, we know now that mutations in 13 different genes can account for ARCI, and more genes will surely be identified in the near future as still not all mutations for all ARCI patients have been identified. Genes and proteins involved in ARCI have been well studied, this enables us today to replace missing proteins (or genes) in patient-specific therapy approaches. Nevertheless, some patients showing the very identical mutation in the same gene, even siblings, can show very different severity of the disease. These changes might be caused very small and not yet fully understood epigenetic differences. The role of DNA methylation and histone modification on ARCI clinical outcome and current and future therapeutics has not yet been studied. We have now engaged in a pilot study to highlight epigenetic difference between healthy control keratinocytes and cells from a TGM1-deficient ARCI patient.
Our first preliminary data has recently been accepted for presentation. Please find an excerpt of our abstract in the following. We seek to further this project by increasing sample numbers and engaging in WGSBS, ChIP-Seq and RNA-Seq by co-operating with a genomics facility for an in-depths understanding of epigenetic mechanisms in keratinisation disorders.
“….To investigate differences between patient and control samples, keratinocytes were cultured under low calcium conditions until confluent. Cells were then subjected to calcium treatment for five days to allow terminal differentiation. DNA or chromatin complexes were isolated following manufacturers recommendations (Qiagen, Manchester, UK) and subjected to either array/qPCR-based DNA-methylation analysis or array/qPCR/ChIP-based histone modification investigations. We used a custom-made qPCR array with genes involved in epidermal differentiation, barrier formation and ectodermal gatekeeping for DNA-methylation studies and focused on the role of H3K4me1, H3K27ac and DNp63 antibody binding sites while studying histone modifications in epidermal pathways……. “
- Andrews K*, Brennan L*, Blacklock L, Hennies HC, Marriott A, Eckl KM. Understanding methylation patterns and histone modification changes in keratinocytes from ARCI patients (2018) Annual meeting of the British Society for Dermatological Research. * Authors contributed equally