Role of microRNA-23b in flow-regulation of Rb phosphorylation and endothelial cell growth

Abstract

MicroRNAs (miRs) can regulate many cellular functions, but their roles in regulating responses of vascular endothelial cells (ECs) to mechanical stimuli remain unexplored. We hypothesize that the physiological responses of ECs are regulated by not only mRNA and protein signaling networks, but also expression of the corresponding miRs. EC growth arrest induced by pulsatile shear (PS) flow is an important feature for flow regulation of ECs. miR profiling showed that 21 miRs are differentially expressed (8 up-and 13 downregulated) in response to 24-h PS as compared to static condition (ST). The mRNA expression profile indicates EC growth arrest under 24-h PS. Analysis of differentially expressed miRs yielded 68 predicted mRNA targets that overlapped with results of microarray mRNA profiling. Functional analysis of miR profile indicates that the cell cycle network is highly regulated. The upregulation of miR-23b and miR-27b was found to correlate with the PS-induced EC growth arrest. Inhibition of miR-23b using antagomir-23b oligonucleotide (AM23b) reversed the PSinduced E2F1 reduction and retinoblastoma (Rb) hypophosphorylation and attenuated the PS-induced G1/G0 arrest. Antagomir AM27b regulated E2F1 expression, but did not affect Rb and growth arrest. Our findings indicate that PS suppresses EC proliferation through the regulation of miR-23b and provide insights into the role of miRs in mechanotransduction.cell cycle | shear | bioinformatics | gene regulation | mechanotransduction H emodynamic forces, e.g., stretch and shear stress, act constantly on the vascular endothelial cells (ECs) to modulate EC signaling, gene expression, and physiological functions (1). Atherosclerotic lesions in the arterial tree are found mainly at branch points, where blood flow is disturbed with a limited forwarding direction, but are generally spared at the straight parts of the arterial tree, where the flow is laminar with a large forwarding direction (2). Exposure of ECs to 24 h of steady laminar shear flow at 12 dyn/cm 2 (approximating the hemodynamic force in straight parts of arteries) leads to antiproliferative (3) and antiinflammatory (4) responses. In contrast, ECs exposed to disturbed flow, mimicking the hemodynamic force at branch points, exhibit opposite responses (5, 6). The laminar shear-induced EC growth arrest involves the expression of CDK inhibitors (e.g., p21 cip , p27 kip ), tumor suppressor p53, and retinoblastoma (Rb) hypophosphorylation (3, 7). Whereas there is considerable knowledge on mechanotransduction at protein and mRNA levels, there is little information on the role of microRNAs (miRs) in this process.miRs are small noncoding RNAs (∼21-25 nucleotides) that regulate gene expression by binding to target mRNAs to cause their degradation or translational repression (8). It is estimated that miRs regulate ∼30% of human protein-coding genes. More than 800 miRs have been identified in the human genome and registered in the Sanger miRBase. These small RNAs provide a powerful mechanism for posttranscriptional cont...

Multiple miRNAs jointly regulate the biosynthesis of ecdysteroid in the holometabolous insects, Chilo suppressalis

“…It should be noticed that 1351 miRNAs were from 12 Drosophila species, which accounted for about half of known insect miRNAs (Kozomara and Griffiths-Jones 2014). Many studies to elucidate the functions of miRNAs in regulating a variety of insect physiological processes have been carried out, such as in metamorphosis development (Sokol et al 2008;Gomez-Orte and Belles 2009;Ling et al 2014;Belles 2017;Wu et al 2017), cell growth (Wang et al 2010), behavior (Cohen et al 2017), sex determination (McJunkin and Ambros 2017), oogenesis , embryogenesis (Jannot et al 2016), immunity (Zhu et al 2013), insect-pathogen interactions (Hussain and Asgari 2010;Asgari 2013;Wu et al 2016), etc. Several miRNAs have been reported to regulate insect metamorphosis by targeting genes either in the ecdysone cascade or the JH cascade (Zhang et al 2009;Belles 2017).…”

Downregulation of mir-23b in plasma is associated with poor prognosis in patients with colorectal cancer

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The atypical mechanosensitive microrna-712 derived from pre-ribosomal RNA induces endothelial inflammation and atherosclerosis

“…LS stimulates expression of miR-10a, miR-19a, miR-21, miR-23b, miR-101, and miR-143/145, mediating anti-atherogenic events 37,38,39,40,41,42 , while OS induces expression of miR-21, miR-92a, and miR-663 leading to proatherogenic responses 14,43,44 . miR-155 is also flow-sensitive miRNA but its role in atherosclerosis is controversial 45 .…”