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Touma F, Lambert M, Martínez Villarreal A, Gantchev J, Ramchatesingh B, Litvinov IV. The Ultraviolet Irradiation of Keratinocytes Induces Ectopic Expression of LINE-1 Retrotransposon Machinery and Leads to Cellular Senescence. Biomedicines 2023; 11:3017. [PMID: 38002016 PMCID: PMC10669206 DOI: 10.3390/biomedicines11113017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/26/2023] Open
Abstract
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 LINE-1 retrotransposons. The ectopic expression of LINE-1 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 LINE-1 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 LINE-1 and senescence markers that were upregulated after several NB-UVB exposures. Selected miRNAs that are known to bind LINE-1 mRNA were measured using RT-qPCR, and the expression of miR-16 was downregulated with UVB exposure. Our findings demonstrate that UVB irradiation induces LINE-1 reactivation and DNA damage in normal keratinocytes along with the associated upregulation of cellular senescence markers and change in miR-16 expression.
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Affiliation(s)
- Fadi Touma
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
- Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 2M1, Canada
| | - Marine Lambert
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
| | - Amelia Martínez Villarreal
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
| | - Jennifer Gantchev
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
| | - Brandon Ramchatesingh
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
| | - Ivan V. Litvinov
- Research Institute, McGill University Health Centre, McGill University, Montreal, QC H4A 3J1, Canada; (F.T.); (B.R.)
- Department of Dermatology, McGill University, Montreal, QC H4A 3J1, Canada
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