Transcriptomic profiling and pathway analysis of cultured human lung microvascular endothelial cells following ionizing radiation exposure

• Published in: Scientific reports 2021-12, Vol.11 (1), p.24214-24214, Article 24214
• Main Authors: Bouten, Roxane M., Dalgard, Clifton L., Soltis, Anthony R., Slaven, John E., Day, Regina M.
• Format: Article
• Language: English
• Subjects: 631/337; 631/80; AKT protein; Apoptosis; Cell Cycle; Cells, Cultured - radiation effects; Cellular Senescence; Cyclin-dependent kinase inhibitor p21; Cytokines; Deoxyribonucleic acid; DNA; DNA Damage; Endothelial cells; Endothelial Cells - cytology; Epithelial-Mesenchymal Transition; Fibrosis; Gene expression; Gene Expression Profiling; Gene Expression Regulation - radiation effects; Humanities and Social Sciences; Humans; Inflammation; Ionizing radiation; Irradiation; Lung - metabolism; Lung - radiation effects; Lung diseases; MDM2 protein; Mesenchyme; Microcirculation; Microvasculature; multidisciplinary; Necrosis; Phosphorylation; Post-irradiation; Pulmonary Fibrosis; Radiation; Radiation, Ionizing; RNA, Messenger - metabolism; RNA-Seq; Science; Science (multidisciplinary); Senescence; Time Factors; Transcriptome; Transcriptomics; Vascular system; Western blotting; X-Rays
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-03636-7

The vascular system is sensitive to radiation injury, and vascular damage is believed to play a key role in delayed tissue injury such as pulmonary fibrosis. However, the response of endothelial cells to radiation is not completely understood. We examined the response of primary human lung microvascular endothelial cells (HLMVEC) to 10 Gy (1.15 Gy/min) X-irradiation. HLMVEC underwent senescence (80–85%) with no significant necrosis or apoptosis. Targeted RT-qPCR showed increased expression of genes CDKN1A and MDM2 (10–120 min). Western blotting showed upregulation of p2/waf1, MDM2, ATM, and Akt phosphorylation (15 min–72 h). Low levels of apoptosis at 24–72 h were identified using nuclear morphology. To identify novel pathway regulation, RNA-seq was performed on mRNA using time points from 2 to 24 h post-irradiation. Gene ontology and pathway analysis revealed increased cell cycle inhibition, DNA damage response, pro- and anti- apoptosis, and pro-senescence gene expression. Based on published literature on inflammation and endothelial-to-mesenchymal transition (EndMT) pathway genes, we identified increased expression of pro-inflammatory genes and EndMT-associated genes by 24 h. Together our data reveal a time course of integrated gene expression and protein activation leading from early DNA damage response and cell cycle arrest to senescence, pro-inflammatory gene expression, and endothelial-to-mesenchymal transition.