661 Understanding the role of ABCA12 in the pathogenesis of harlequin ichthyosis

Abstract

MicroRNAs are considered to play critical roles in the pathogenesis of psoriasis. The purpose of this study was to explore the molecular mechanism of miR-20a-3p in the pathogenesis of IL-22-induced psoriasis. We found that miR-20a-3p was down-regulated in HaCaT cells (human keratinocytes) treated by IL-22 stimulation and in psoriatic lesions. MiR-20a-3p mimics and inhibitors were transfected into HaCaT cells. CCK8 assay and 5-Ethynyl-2'deoxyuridine(EDU) incorporation assay were used for cell proliferation. Annexin fluorescein isothiocyanate/propidium iodide assay was performed to detect cell apoptosis. Results showed that overexpression of miR-20a-3p in HaCaT cells suppressed proliferation and induced apoptosis. Conversely, inhibition of endogenous miR-20a-3p promoted cell proliferation and reduces cell apoptosis. SFMBT1 was identified as one of the direct targets of miR-20a-3p by dual luciferase reporter assay. Knocked down of SFMBT1 by specific RNAi inhibited cell growth and induced apoptosis, which was consistent with the function of miR-20a-3p upregulation in HaCaT cells. In addition, results of western blot analysis showed that miR-20a-3p upregulation or SFMBT1 knockdown promoted the protein expression levels of TGF-b1 and P-Smad2/3. Our findings suggest that miR-20a-3p play important roles through targeting SFMBT1 and TGF-b/smad signalling pathway, and loss of miR-20a-3p in psoriasis may contribute to hyperproliferation and aberrant apoptosis of keratinocytes. Atopic Dermatitis (AD) is a complex disease involving causative effects from both intrinsic and extrinsic sources. Murine models of the disease often fall short in one of these components and as a result, do not fully encapsulate the disease mechanisms. We aimed to determine whether the protease-activated 2 receptor over-expressor mouse with topical house-dust mite application (PAR2 + HDM) is a comprehensive representation of clinical AD in a murine model. Comparison of control groups with the PAR2 + HDM mice was performed to assess AD clinical scoring, skin morphology, barrier function and inflammation. Skin morphology was visualised using H&E staining and barrier function was assessed by transepidermal water loss (TEWL) measurements. Inflammation was evaluated by histological staining for immune cells. Differentially expressed genes (DEGs) were compared in the PAR2 + HDM model with other murine AD models and human AD transcriptome. Our PAR2 + HDM model accurately displays the characteristic clinical symptoms, skin morphology and inflammation seen in AD patients. TEWL is significantly increased in the area of HDM application (p<0.01). There is a significant influx of mast cells (p<0.01) and eosinophils (p<0.0001) into the dermis. The PAR2 + HDM model also shows similar expression pattern of key DEGs (e.g. IL-4, FLG, IVL) as both human AD and other murine models. We found that the PAR2 + HDM model presents with a classic AD pathophysiology and is valuable in terms of reproducibility and overall disease representation. 658In vivo confocal Raman spectro...