MicroRNA-Mediated Downregulation of HMGB2 Contributes to Cellular Senescence in Microvascular Endothelial Cells

Abstract

High mobility group box 2 (HMGB2) is a non-histone chromosomal protein involved in various biological processes, including cellular senescence. However, its role in cellular senescence has not been evaluated extensively. To determine the regulatory role and mechanism of HMGB2 in cellular senescence, we performed gene expression analysis, senescence staining, and tube formation assays using young and senescent microvascular endothelial cells (MVECs) after small RNA treatment or HMGB2 overexpression. HMGB2 expression decreased with age and was regulated at the transcriptional level. siRNA-mediated downregulation inhibited cell proliferation and accelerated cellular senescence. In contrast, ectopic overexpression delayed senescence and maintained relatively higher tube-forming activity. To determine the HMGB2 downregulation mechanism, we screened miRNAs that were significantly upregulated in senescent MVECs and selected HMGB2-targeting miRNAs. Six miRNAs, miR-23a-3p, 23b-3p, -181a-5p, -181b-5p, -221-3p, and -222-3p, were overexpressed in senescent MVECs. Ectopic introduction of miR-23a-3p, -23b-3p, -181a-5p, -181b-5p, and -221-3p, with the exception of miR-222-3p, led to the downregulation of HMGB2, upregulation of senescence-associated markers, and decreased tube formation activity. Inhibition of miR-23a-3p, -181a-5p, -181b-5p, and -221-3p delayed cellular senescence. Restoration of HMGB2 expression using miRNA inhibitors represents a potential strategy to overcome the detrimental effects of cellular senescence in endothelial cells.

MicroRNA miR-214-5p induces senescence of microvascular endothelial cells by targeting the JAG1/Notch signaling pathway

“…To identify unidentified SA-miRNAs, we analyzed small RNA sequencing data obtained from the replicative senescent MVECs model (GSE192677, [ 25 ]). The screening criteria for SA-miRNAs were as follows: 1) an increase of ≥1.3 times in old MVECs compared to that in young MVECs, and 2) raw data reading of log 2 ≥ 4.…”

“…The small RNA sequencing data were retrieved from the GEO database (GSE192677) and bioinformatic data analysis were performed by ebiogen (Seoul, Korea) as previously described [ 25 ].…”

“…Quantitative reverse transcription PCR was performed as previously described [ 25 ]. To analyze miRNA expression, cDNA was synthesized using the Mir-X miRNA First-Strand Synthesis Kit (Clontech Laboratories, Palo Alto, CA, USA).…”

“…Previously, we reported that SA-miRNAs downregulate the high mobility group protein B2 (HMGB2) and contribute to cellular senescence in the microvascular endothelial cells (MVECs) [ 25 ]. Here, we focused on identifying more SA-miRNAs in MVECs as potential diagnostic means and promising therapeutic targets to delay vascular aging.…”

Downregulation of High mobility group box 2 relieves spinal cord injury by inhibiting microglia-mediated neuroinflammation

“…As a group of plentiful chromatin-binding proteins in the nucleus of mammal cells, High mobility group box proteins (HMGBs) contain a long acidic C-terminal domain and two DNA-binding HMGB domains, which bind distorted DNA [12,13].…”