405 Understanding the biologic regulation and impact of Long Interspersed Nuclear Element (LINE-1) retrotransposon reactivation in keratinocytes undergoing phototherapy treatments.

Narrow band ultraviolet B (NB-UVB) and Broad (BB-UVB) are commonly used for the treatment of Atopic Dermatitis (AD) among others, has been shown by us others to trigger LINE-1 reactivation in human keratinocytes. constitutes ∼17% genome, played important evolutionary role, its may result deleterious effects leading DNA damage, cellular senescence photoaging. We established a model NB-UVB or BB-UVB irradiation on keratinocytes, showed that these induced an increase expression. Moreover, we were able observe repetition this irradiation, thus long terme overexpression, markers, double strand breaks, decrease cell proliferation. On other hand, found some small RNAs, target silico, decreased our UV model, compared control. Thus, identifying RNAs involved regulation, deregulated response will be better characterize mechanisms during attempt remedy them. The impact restoration adequate level regulatory evaluated expression, as well genomic instability Ultimately, would like correlate results with those patients AD treated UV. Furthermore, confirming patient samples, help understand potential UVB photoaging, treatments skin inflammation new biological parameters (e.g., ointment containing microRNA(s) interest), which prevent reduce L1 activation.