Effects of Isotretinoin Treatment on Epigenetic Programming in T Cells
Eugenia Becker, Claudia Stanzel, Kirstin Atrott, Gerhard Rogler, Isabelle Frey-Wagner
Background
Retinoids are essential nutrients involved in the maturation of the immune
system. The majority of in vitro and in vivo studies provided evidence that retinoid treatment
exhibits anti-inflammatory properties and is effective acne therapy. However, there is a
controversial discussion about a causal relationship between isotretinoin treatment and the
onset of inflammatory bowel disease (IBD). Some patients have claimed that they developed
acute intestinal inflammation during isotretinoin treatment or had an onset of IBD weeks
or even years after cessation of the medication. We have previously shown that isotretinoin
treatment has no adverse effects in two mouse models of inflammatory bowel disease. Here
we investigated the influence of isotretinoin treatment on genetic imprinting in two T cells
subsets as a potential mediator of long-term effects of isotretinoin treatment on the immune
system. Methods Balb/c mice were treated with isotretinoin (30 mg/kg bodyweight) or vehicle
orally for 2 weeks and kept for further 4 weeks to study potential direct and long-term
effects. Naive T cells and regulatory T cells were isolated directly after the treatment period
and at the end of the study by magnetic cell sorting. After isolation of genomic DNA,
microRNA and mRNA, samples were sequenced with the Illumina® technique to study
changes in methylation patterns, microRNA and mRNA expression. For predicting target
genes of determined microRNAs the software Target Scan and Traget Scan Custom were
used. For identification of pathways significantly affected by isotretinoin treatment the
software Meta Core® was applied. Results Analysis of epigenetic modifications in naive and
regulatory T cells revealed potential long-term effects in both T cells subsets. In regulatory
T cells mainly the methylation pattern was altered in T cells isolated four weeks after cessation
of treatment. In naive T cells on the other hand predominantly microRNA expression was
altered in T cells isolated after four weeks without treatment. Pathway analysis by Meta
Core® revealed that pathways of immune responses, concerning antigen presentation and
T helper cell differentiation were affected. Further functional analysis of affected pathways
is currently under investigation.
Conclusions
Preliminary results identified changes in methylation pattern and microRNA expression in naive and regulatory T cells which might mediate
potential long-term effects after isotretinoin treatment, yet differences between the different
T cell subsets were far more pronounced than differences induced by isotretinoin treatment.