Dysregulated miR-125a promotes angiogenesis through enhanced glycolysis

Abstract

BackgroundAlthough neoangiogenesis is a hallmark of chronic inflammatory diseases such as inflammatory arthritis and many cancers, therapeutic agents targeting the vasculature remain elusive. Here we identified miR-125a as an important regulator of angiogenesis.MethodsMiRNA levels were quantified in Psoriatic Arthritis (PsA) synovial-tissue by RT-PCR and compared to macroscopic synovial vascularity. HMVEC were transfected with anti-miR-125a and angiogenic mechanisms quantified using tube formation assays, transwell invasion chambers, wound repair, RT-PCR and western blot. Real-time analysis of EC metabolism was assessed using the XF-24 Extracellular-Flux Analyzer. Synovial expression of metabolic markers was assessed by immunohistochemistry and immunofluorescent staining. MiR-125a CRISPR/Cas9-based knock-out zebrafish were generated and vascular development assessed. Finally, glycolytic blockade using 3PO, which inhibits Phosphofructokinase-fructose-2,6-bisphophatase 3 (PFKFB3), was assessed in miR-125a−/− ECs and zebrafish embryos.FindingsMiR-125a is significantly decreased in PsA synovium and inversely associated with macroscopic vascularity. In-vivo, CRISPR/cas9 miR-125a−/− zebrafish displayed a hyper-branching phenotype. In-vitro, miR-125a inhibition promoted EC tube formation, branching, migration and invasion, effects paralleled by a shift in their metabolic profile towards glycolysis. This metabolic shift was also observed in the PsA synovial vasculature where increased expression of glucose transporter 1 (GLUT1), PFKFB3 and Pyruvate kinase muscle isozyme M2 (PKM2) were demonstrated. Finally, blockade of PFKFB3 significantly inhibited anti-miR-125a-induced angiogenic mechanisms in-vitro, paralleled by normalisation of vascular development of CRISPR/cas9 miR-125a−/− zebrafish embryos.IntepretationOur results provide evidence that miR-125a deficiency enhances angiogenic processes through metabolic reprogramming of endothelial cells.FundIrish Research Council, Arthritis Ireland, EU Seventh Framework Programme (612218/3D-NET).

Serum miRNA Signature in Rheumatoid Arthritis and “At-Risk Individuals”

“…Consistent with these studies we also demonstrated a significant increase in miR-146 and miR-223 in RA and arthralgia compared to HC ( 31 , 35 , 51 , 52 ), however these weren’t as significant as the nine miRNA identified. In addition both MiR-125a-5p and miR-16-5p were significantly increased in RA vs Arthralgia, consistent with previous studies demonstrating higher levels in established RA and PsA ( 14 , 53 – 56 ), with studies showing that they also mediate RAFLS function, macrophage plasticity and regulates pro-apoptotic and metabolic pathways in CD14+ monocytes ( 14 , 53 – 57 ). Furthermore, miR-125b is also associated with good clinical response in RA patients 3 months post rituximab treatment ( 58 ).…”

“…Interestingly no change was observed for miR-155, which has previously been shown to be elevated in various different cell-types in RA, in addition to influencing B cell function and monocyte apoptotic mechanism ( 33 , 34 , 36 , 50 ). These differences may be due to heterogeneity of patient cohorts, in addition miRNA analysis can depend on the site and cell type, with studies also showing an inverse relationship in miRNA levels between systemic and local inflammation ( 56 ).…”

mTORC1 as a Regulator of Mitochondrial Functions and a Therapeutic Target in Cancer

“…On the other hand it was reported that several miRNAs targeting several mRNAs of nuclear-encoded mitochondrial proteins, integrating miRNAs into the landscape of translational regulation of mitochondrial functions such as TCA cycle, production of ROS and glutamine metabolism and mitochondrial fission process (82). miR-125a is frequently downregulated in several human cancer such as ovarian, non small-cell lung and gastric cancer and colorectal cancer (83-85) Moreover low expression of miR-125a is associated with increased tumor diameter, high Ki67 expression and poor overall survival of patients with gastric carcinoma (86) Additionally miR-125a deficiency enhances agiogenic processes through metabolic reprogramming of endothelial cells (87). Interestingly it was demonstrated that miR-125a is decreased in pancreatic cancer cells (PANC-1), accompanied by an increase in the contents of mitofusin 2 (MFN2) an important regulator of mitochondrial fission.…”

MicroRNAs in Synovial Pathology Associated With Osteoarthritis

“…This effect can be counteracted by other miRNAs. MiR-125a is expressed at higher levels in OA synovium compared to psoriatic arthritis and modulates glycolysis in human umbilical vein endothelial cells (HUVEC) to inhibit angiogenesis ( 36 ). MiRNAs are dysregulated in the synovium during OA, but the way in which they regulate inflammation, angiogenesis or ECM modulation, and how they interact to maintain the joint homeostasis, remains poorly understood and requires extensive investigation in near future.…”