Touma Fadi, Lambert Marine, Martínez Villarreal Amelia, Gantchev Jennifer, Ramchatesingh Brandon, Litvinov Ivan V
Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada.
Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 2M1, Canada.
Biomedicines. 2023 Nov 10;11(11):3017. doi: 10.3390/biomedicines11113017.
Retrotransposons have played an important role in evolution through their transposable activity. The largest and the only currently active human group of mobile DNAs are the retrotransposons. The ectopic expression of has been correlated with genomic instability. Narrow-band ultraviolet B (NB-UVB) and broad-band ultraviolet B (BB-UVB) phototherapy is commonly used for the treatment of dermatological diseases. UVB exposure is carcinogenic and can lead, in keratinocytes, to genomic instability. We hypothesize that reactivation occurs at a high rate in response to UVB exposure on the skin, which significantly contributes to genomic instability and DNA damage leading to cellular senescence and photoaging. Immortalized N/TERT1 and HaCaT human keratinocyte cell lines were irradiated in vitro with either NB-UVB or BB-UVB. Using immunofluorescence and Western blotting, we confirmed UVB-induced protein expression of LINE-1. Using RT-qPCR, we measured the mRNA expression of and senescence markers that were upregulated after several NB-UVB exposures. Selected miRNAs that are known to bind mRNA were measured using RT-qPCR, and the expression of was downregulated with UVB exposure. Our findings demonstrate that UVB irradiation induces reactivation and DNA damage in normal keratinocytes along with the associated upregulation of cellular senescence markers and change in expression.
逆转录转座子通过其转座活性在进化中发挥了重要作用。逆转录转座子是人类移动DNA中最大且目前唯一活跃的群体。其异位表达与基因组不稳定相关。窄谱中波紫外线（NB-UVB）和宽谱中波紫外线（BB-UVB）光疗常用于治疗皮肤病。紫外线B（UVB）照射具有致癌性，可导致角质形成细胞基因组不稳定。我们假设，皮肤暴露于UVB会导致逆转录转座子大量重新激活，这显著促成了基因组不稳定和DNA损伤，进而导致细胞衰老和光老化。使用NB-UVB或BB-UVB对永生化的N/TERT1和HaCaT人角质形成细胞系进行体外照射。通过免疫荧光和蛋白质免疫印迹法，我们证实了UVB诱导的LINE-1蛋白表达。使用逆转录定量聚合酶链反应（RT-qPCR），我们测量了多次NB-UVB照射后上调的逆转录转座子和衰老标志物的mRNA表达。使用RT-qPCR测量已知与逆转录转座子mRNA结合的特定微小RNA（miRNA），UVB照射后逆转录转座子的表达下调。我们的研究结果表明，UVB照射可诱导正常角质形成细胞中的逆转录转座子重新激活和DNA损伤，同时伴随细胞衰老标志物的相关上调以及逆转录转座子表达的变化。
