Differential miRNA expression profiles in proliferating or differentiated keratinocytes in response to gamma irradiation

Abstract

BackgroundMicroRNAs (miRNAs), a group of short non-coding RNAs that negatively regulate gene expression, have recently emerged as potential modulators of cellular response to ionizing radiations both in vitro and in vivo in various cell types and tissues. However, in epidermal cells, the involvement of the miRNA machinery in the cellular response to ionizing radiations remains to be clarified. Indeed, understanding the mechanisms of cutaneous radiosensitivity is an important issue since skin is the most exposed organ to ionizing radiations and among the most sensitive.ResultsWe settled up an expression study of miRNAs in primary human skin keratinocytes using a microfluidic system of qPCR assay, which permits to assess the expression of almost 700 annotated miRNAs. The keratinocytes were cultured to a proliferative or a differentiated state mimicking basal or suprabasal layers of human epidermis. These cells were irradiated at 10 mGy or 6 Gy and RNA was extracted 3 hours after irradiation. We found that proliferative cells irradiated at 6 Gy display a global fall of miRNA expression whereas differentiated cells exposed to the same dose display a global increase of miRNAs expression. We identified twenty miRNAs weakly but significantly modulated after 6 Gy irradiation, whereas only 2 miRNAs were modulated after low-dose irradiation in proliferating cells. To go further into the biological meaning of this miRNA response, we over-expressed some of the responding miRNA in proliferating cells: we observed a significant decrease of cell viability 72 hours after irradiation. Functional annotation of their predicted targets revealed that G-protein related pathways might be regulated by these responding miRNAs.ConclusionsOur results reveal that human primary keratinocytes exposed to ionizing irradiation expressed a miRNA pattern strongly related to the differentiation status of irradiated cells. We also demonstrate that some miRNAs play a role in the radiation response to ensure the short-term survival of irradiated keratinocytes.

Distinct microRNA Expression Profiles in Mouse Renal Cortical Tissue after 177Lu-octreotate Administration

“…These findings are in agreement with recent studies showing dose-dependent changes in miRNA expression levels, e.g., Templin et al who reported a higher number of differentially regulated miRNAs in blood samples collected from mice exposed to 1 Gy compared with 0.5 Gy from 600 MeV protons (19 vs. 5 regulated miRNAs at 6 h and 6 vs. 3 regulated miRNAs at 24 h after irradiation) [36]. Dose-dependent miRNA regulation was also found in proliferating keratinocytes in vitro , where exposure to 10 mGy ( 137 Cs) revealed fewer regulated miRNAs compared with exposure to 6 Gy 3 h after irradiation (2 vs. 8 regulated miRNAs) [37]. Furthermore, the lack of a dose-response in the number of regulated transcripts at doses higher than 0.13 Gy could be expected.…”

Differential miRNA expression profiles in the longissimus dorsi muscle between intact and castrated male pigs

“…The prediction results are a combination of these two queries. GO enrichment analysis was performed using the Gorilla tool (http://cbl-gorilla.cs.technion.ac.il/) (Eden et al, 2009;Joly-Tonetti et al, 2013). Probability values were corrected through the Benjamini and Hochberg's false discovery rate (FDR) method and considered significant if the corrected P-value was less than 0.05 (Joly-Tonetti et al, 2013).…”

“…GO enrichment analysis was performed using the Gorilla tool (http://cbl-gorilla.cs.technion.ac.il/) (Eden et al, 2009;Joly-Tonetti et al, 2013). Probability values were corrected through the Benjamini and Hochberg's false discovery rate (FDR) method and considered significant if the corrected P-value was less than 0.05 (Joly-Tonetti et al, 2013). In addition, Cytoscape software (Cline et al, 2007) was used to construct the miRNA-mRNA network based on regulatory interactions between differentially expressed miRNAs and target GO genes.…”

microRNAs in Cancer Cell Response to Ionizing Radiation

“…One study, published this year, demonstrated that IR has little to no affect on Dicer1 or AGO2 expression in keratinocytes (63). In addition, Kraemer et al used siRNA to Dicer and AGO2 to demonstrate an essential function for miRNAs in IR survival response in endothelial cells (67).…”