MicroRNA Sequencing of Discoid Lupus Erythematosus Skin

Background Discoid lupus erythematous (DLE) is an autoimmune skin condition that causes profound disfigurement. Environmental effects are linked to increased risk and worsening disease off activity in DLE. MicroRNA (miRNA) are increasingly found to have important roles in the environmental modulation of inflammation and cellular differentiation in autoimmune diseases. Objective The goal of the pilot study was to comprehensively identify the miRNA transcriptome in DLE. Methods The specimens were from African American women (DLE=4, normal=4) and were age‐matched [median age=55 years (range=50–61), median DLE duration=18 years]. Subjects with DLE did not have concomitant systemic lupus and were not on systemic immunosuppression during skin biopsy. Skin specimens were composed of keratinocytes, epidermal appendages, vasculature, dermal fibroblasts and skin homing immune cell populations. We extracted total RNA using a method that preserved small RNAs (Ambion). RNA was prepared for sequencing with the Small RNA Sample Prep Kit,□□ □□ adapters were ligated to approximately 1 microgram of total RNA. Each library was loaded on a single Illumina lane at 20 picogram and subjected to 86 cycles of sequencing on HiSeq. We generated 52.4 million raw and 15.3 million qualified reads. We mapped qualified reads to miRNA precursors, functional non‐coding RNAs and build 37 (hg19) of the human genome. The adapter‐trimmed, qualified reads were distributed around an average length of 21 nucleotides. The number of reads and mapping proportions in the DLE group approximate that in the normal skin groups. We detected mature miRNAs derived from 1240 known miRNA precursor families. These were represented by at least one read in the cumulative data set. We analyzed the data from our next generation sequencing based on relative comparisons of normalized read counts between DLE and normal skin to detect relative changes. Standardized fold changes of miRNAs were calculated as mean differences in read counts divided by pooled standard deviations in the log scale. Results We identified 18 known miRNAs that were significantly over or under expressed in active DLE lesions versus normal skin (p‐values < 0.05). Among these are mir‐146a, mir‐223, mir‐21, mir‐23b. These miRNAs are linked to IFN‐regulation, hypomethylation, ultraviolet exposure, differentiation of the keratinocytes, epidermal dendritic cells, and T cells, and estrogen response. Conclusion From this discovery‐based study, we have identified several miRNAs that may play an important role in epigenetic regulation in DLE that ultimately affects disease severity. Support or Funding Information CTSA of University of Cincinnati This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .