Background Colorectal cancer patients have an increased risk of developing venous thromboembolism (VTE), resulting in increased morbidity and mortality. Because the exact mechanism is yet unknown,... Show moreBackground Colorectal cancer patients have an increased risk of developing venous thromboembolism (VTE), resulting in increased morbidity and mortality. Because the exact mechanism is yet unknown, risk prediction is still challenging; therefore, new biomarkers are needed. MicroRNAs (miRNAs) are small, relatively stable RNAs, that regulate a variety of cellular processes, and are easily measured in body fluids. Objective The aim of this study was to identify novel tumor-expressed miRNAs associated with VTE. Methods In a cohort of 418 colorectal cancer patients diagnosed between 2001 and 2015 at the Leiden University Medical Center, 23 patients (5.5%) developed VTE 1 year before or after cancer diagnosis. Based on availability of frozen tumor material, tumor cells of 17 patients with VTE and 18 patients without VTE were isolated using laser capture microdissection and subsequently analyzed on the Illumina sequencing platform NovaSeq600 using 150-bp paired-end sequencing. Cases and controls were matched on age, sex, tumor stage, and grade. Differential miRNA expression was analyzed using edgeR. Results A total of 547 miRNAs were detected. Applying a 1.5-fold difference and false discovery rate of <0.1, 19 tumor-miRNAs were differentially regulated in VTE cases versus controls, with hsa-miR-3652, hsa-miR-92b-5p, and hsa-miR-10,394-5p as most significantly downregulated. Seven of the 19 identified miRNAs were predicted to regulate the gonadotropin-releasing hormone receptor pathway. Conclusion We identified 19 differentially regulated tumor-expressed miRNAs in colorectal cancer-associated VTE, which may provide insights into the biological mechanism and in the future might have potential to serve as novel, predictive biomarkers. Show less
Bijkerk, R.; Kallenberg, M.H.; Zijlstra, L.E.; Berg, B.M. van den; Bresser, J. de; Hammer, S.; ... ; Mooijaart, S. 2022
Background: The prevalence of end-stage renal disease (ESRD) is increasing worldwide, with the majority of new ESRD cases diagnosed in patients >60 years of age. These older patients are at... Show moreBackground: The prevalence of end-stage renal disease (ESRD) is increasing worldwide, with the majority of new ESRD cases diagnosed in patients >60 years of age. These older patients are at increased risk for impaired cognitive functioning, potentially through cerebral small vessel disease (SVD). Novel markers of vascular integrity may be of clinical value for identifying patients at high risk for cognitive impairment. Methods: We aimed to associate the levels of angiopoietin-2 (Ang-2), asymmetric dimethylarginine and a selection of eight circulating angiogenic microRNAs (miRNAs) with SVD and cognitive impairment in older patients reaching ESRD that did not yet initiate renal replacement therapy (n = 129; mean age 75.3 years, mean eGFR 16.4 mL/min). We assessed brain magnetic resonance imaging changes of SVD (white matter hyperintensity volume, microbleeds and the presence of lacunes) and measures of cognition in domains of memory, psychomotor speed and executive function in a neuropsychological test battery. Results: Older patients reaching ESRD showed an unfavourable angiogenic profile, as indicated by aberrant levels of Ang-2 and five angiogenic miRNAs (miR-27a, miR-126, miR-132, miR-223 and miR-326), compared with healthy persons and patients with diabetic nephropathy. Moreover, Ang-2 was associated with SVD and with the domains of psychomotor speed and executive function, while miR-223 and miR-29a were associated with memory function. Conclusions: Taken together, these novel angiogenic markers might serve to identify older patients with ESRD at risk of cognitive decline, as well as provide insights into the underlying (vascular) pathophysiology. Show less
Homberg, D.A.L. van den; Kwast, R.V.C.T. van der; Quax, P.H.A.; Nossent, A.Y. 2022
N-6-methyladenosine (m6A) is the most prevalent post-transcriptional RNA modification in eukaryotic cells. The modification is reversible and can be dynamically regulated by writer and eraser... Show moreN-6-methyladenosine (m6A) is the most prevalent post-transcriptional RNA modification in eukaryotic cells. The modification is reversible and can be dynamically regulated by writer and eraser enzymes. Alteration in the levels of these enzymes can lead to changes in mRNA stability, alternative splicing or microRNA processing, depending on the m6A-binding proteins. Dynamic regulation of mRNA m6A methylation after ischemia and hypoxia influences mRNA stability, alternative splicing and translation, contributing to heart failure. In this study, we studied vasoactive microRNA m6A methylation in fibroblasts and examined the effect of hypoxia on microRNAs methylation using m6A immunoprecipitation. Of the 19 microRNAs investigated, at least 16 contained m6A in both primary human fibroblasts and a human fibroblast cell line, suggesting vasoactive microRNAs are commonly m6A methylated in fibroblasts. More importantly, we found that mature microRNA m6A levels increased upon subjecting cells to hypoxia. By silencing different m6A writer and eraser enzymes followed by m6A immunoprecipitation, we identified METTL4, an snRNA m6A methyltransferase, to be predominantly responsible for the increase in m6A modification. Moreover, by using m6A-methylated microRNA mimics, we found that microRNA m6A directly affects downstream target mRNA repression efficacy. Our findings highlight the regulatory potential of the emerging field of microRNA modifications. Show less
Catapano, F.; Scaglioni, D.; Maresh, K.; Ala, P.; Domingos, J.; Selby, V.; ... ; Muntoni, F. 2020
Aim: To perform cross-sectional and longitudinal miRNA profiling in plasma from Duchenne muscular dystrophy (DMD) subjects and find non-invasive biomarkers in DMD. Subjects/materials & methods:... Show moreAim: To perform cross-sectional and longitudinal miRNA profiling in plasma from Duchenne muscular dystrophy (DMD) subjects and find non-invasive biomarkers in DMD. Subjects/materials & methods: Plasma was collected from 14 age and sex matched controls and 46 DMD subjects. Free-circulating and extracellular vesicle (EV)-derived miRNA expression was measured by RT-qPCR. Results: Free-circulating and EVs derived miR-29c-3p and miR-133a-3p are dysregulated in DMD subjects. Free-circulating and EV-derived miR-29c-3p are reduced in DMD subjects undergoing daily corticosteroid treatment. Free-circulating miR-1-3p and miR-122-5p are longitudinally upregulated in ambulant DMD subjects. Conclusion: We detected novel free-circulating and EV-derived dysregulated miRNAs in plasma from DMD subjects and characterized the longitudinal profile of free-circulating miRNA on plasma from DMD subjects. Show less
Gray, L.G.; Mills, J.D.; Curry-Hyde, A.; Devore, S.; Friedman, D.; Thom, M.; ... ; Janitz, M. 2020
Circular RNAs (circRNAs) regulate mRNA translation by binding to microRNAs (miRNAs), and their expression is altered in diverse disorders, including cancer, cardiovascular disease, and Parkinson's... Show moreCircular RNAs (circRNAs) regulate mRNA translation by binding to microRNAs (miRNAs), and their expression is altered in diverse disorders, including cancer, cardiovascular disease, and Parkinson's disease. Here, we compare circRNA expression patterns in the temporal cortex and hippocampus of patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) and healthy controls. Nine circRNAs showed significant differential expression, including circRNA-HOMER1, which is expressed in synapses. Further, we identified miRNA binding sites within the sequences of differentially expressed (DE) circRNAs; expression levels of mRNAs correlated with changes in complementary miRNAs. Gene set enrichment analysis of mRNA targets revealed functions in heterocyclic compound binding, regulation of transcription, and signal transduction, which maintain the structure and function of hippocampal neurons. The circRNA-miRNA-mRNA interaction networks illuminate the molecular changes in MTLE, which may be pathogenic or an effect of the disease or treatments and suggests that DE circRNAs and associated miRNAs may be novel therapeutic targets. Show less
Myostatin is a negative regulator of muscle cell growth and proliferation. Furthermore, myostatin directly affects the expression of 14q32 microRNAs by binding the 14q32 locus. Direct inhibition of... Show moreMyostatin is a negative regulator of muscle cell growth and proliferation. Furthermore, myostatin directly affects the expression of 14q32 microRNAs by binding the 14q32 locus. Direct inhibition of 14q32 microRNA miR-495-3p decreased postinterventional restenosis via inhibition of both vascular smooth muscle cell (VSMC) proliferation and local inflammation. Here, we aimed to investigate the effects of myostatin in a mouse model for postinterventional restenosis. In VSMCs in vitro, myostatin led to the dose-specific downregulation of 14q32 microRNAs miR-433-3p, miR-494-3p, and miR-495-3p. VSMC proliferation was inhibited, where cell migration and viability remained unaffected. In a murine postinterventional restenosis model, myostatin infusion did not decrease restenosis, neointimal area, or lumen stenosis. Myostatin inhibited expression of both proliferation marker PCNA and of 14q32 microRNAs miR-433-3p, miR-494-3p, and miR-495-3p dose-specifically in cuffed femoral arteries. However, 14q32 microRNA expression remained unaffected in macrophages and macrophage activation as well as macrophage influx into lesions were not decreased. In conclusion, myostatin did not affect postinterventional restenosis. Although myostatin inhibits 14q32 microRNA expression and proliferation in VSMCs, myostatin had no effect on macrophage activation and infiltration. Our findings underline that restenosis is driven by both VSMC proliferation and local inflammation. Targeting only one of these components is insufficient to prevent restenosis. Show less
Verjans, R.; Peters, T.; Beaumont, F.J.; Leeuwen, R. van; Herwaarden, T. van; Verhesen, W.; ... ; Schroen, B. 2018
