Project description:There are no blood-based molecular biomarkers of temporal lobe epilepsy (TLE) to support clinical diagnosis. MicroRNAs are short noncoding RNAs with strong biomarker potential due to their cell-specific expression, mechanistic links to brain excitability, and stable and reliable detection in biofluids. Altered expression of circulating microRNAs has been reported in human epilepsy, but most studies collected samples from one clinical site, relied on a single platform for profiling or conducted minimal validation. We collected plasma samples from video-electroencephalogram-monitored adult TLE patients at epilepsy specialist centers in two different countries, performed genome-wide PCR-based and RNA sequencing during the discovery phase and validated in a large cohort of samples (>300 samples) that included patients with psychogenic non-epileptic seizures. After profiling, validation of the discovery cohort and validation in the larger patient groups we identified miR-27a-3p, miR-328-3p and miR-654-3p with strong TLE biomarker potential. Plasma levels of these microRNAs were regulated in the same direction in plasma from epileptic mice, and furthermore were not different to healthy controls in patients with psychogenic non-epileptic seizures. The biomarker potential was extended by determining microRNA copy number in plasma and we demonstrate rapid detection of these microRNAs using an electrochemical RNA microfluidic disk as a prototype point-of-care device. Investigation of the molecular transport mechanism in plasma determined analysis of all three microRNAs within the exosome-enriched provided highest diagnostic accuracy while levels of Argonaute-bound miR-328-3p selectively increased in patient samples collected after seizures. In situ hybridization revealed the presence of miR-27a-3p and miR-328-3p within neurons in human brain and bioinformatics analysis predicted targets linked to growth factor signaling and apoptosis. Taken together, this study extends evidence for the biomarker potential of circulating microRNAs for epilepsy diagnosis and mechanistic links to underlying pathomechanisms. microRNA expression in the plasma of 16 patients with TLE, before and after seizure, and 16 controls was measured by TaqMan OpenArray Human MicroRNA Panel.

Project description:MicroRNAs are a class of small non-coding RNA that regulate gene expression at a post-transcriptional level. MicroRNAs have been identified in various body fluids under normal conditions and their stability as well as their dysregulation in disease has led to ongoing interest in their diagnostic and prognostic potential. Circulating microRNAs may be valuable predictors of early-life complications such as birth asphyxia or neonatal seizures but there are relatively few data on microRNA content in plasma from healthy babies. Here we performed small RNA-sequencing analysis of plasma processed from umbilical cord blood in a set of healthy newborns. MicroRNA levels in umbilical cord plasma of four male and four female healthy babies, from two different centres were profiled. A total of 1,004 individual microRNAs were identified, which ranged from 426 to 659 per sample, of which 269 microRNAs were common to all eight samples. Many of these microRNAs are highly expressed and consistent with previous studies using other high throughput platforms. While overall microRNA expression did not differ between male and female cord blood plasma, we did detect differentially edited microRNAs in female plasma compared to male. Of note, and consistent with other studies of this type, adenylation and uridylation were the two most prominent forms of editing. Six microRNAs, miR-128-3p, miR-29a-3p, miR-9-5p, miR-218-5p, 204-5p and miR-132-3p were consistently both uridylated and adenylated in female cord blood plasma. Although only a few microRNAs were differentially edited in females and expression levels were low, it is an interesting finding as the effects of sex on RNA editing is poorly understood and warrants further investigation. These results provide a benchmark for microRNA profiling and biomarker discovery using umbilical cord plasma and can be used as comparative data for future biomarker profiles from complicated births or those with early-life developmental disorders.

Project description:There are no blood-based molecular biomarkers of temporal lobe epilepsy (TLE) to support clinical diagnosis. MicroRNAs are short noncoding RNAs with strong biomarker potential due to their cell-specific expression, mechanistic links to brain excitability, and stable and reliable detection in biofluids. Altered expression of circulating microRNAs has been reported in human epilepsy, but most studies collected samples from one clinical site, relied on a single platform for profiling or conducted minimal validation. We collected plasma samples from video-electroencephalogram-monitored adult TLE patients at epilepsy specialist centers in two different countries, performed genome-wide PCR-based and RNA sequencing during the discovery phase and validated in a large cohort of samples (>300 samples) that included patients with psychogenic non-epileptic seizures. After profiling, validation of the discovery cohort and validation in the larger patient groups we identified miR-27a-3p, miR-328-3p and miR-654-3p with strong TLE biomarker potential. Plasma levels of these microRNAs were regulated in the same direction in plasma from epileptic mice, and furthermore were not different to healthy controls in patients with psychogenic non-epileptic seizures. The biomarker potential was extended by determining microRNA copy number in plasma and we demonstrate rapid detection of these microRNAs using an electrochemical RNA microfluidic disk as a prototype point-of-care device. Investigation of the molecular transport mechanism in plasma determined analysis of all three microRNAs within the exosome-enriched provided highest diagnostic accuracy while levels of Argonaute-bound miR-328-3p selectively increased in patient samples collected after seizures. In situ hybridization revealed the presence of miR-27a-3p and miR-328-3p within neurons in human brain and bioinformatics analysis predicted targets linked to growth factor signaling and apoptosis. Taken together, this study extends evidence for the biomarker potential of circulating microRNAs for epilepsy diagnosis and mechanistic links to underlying pathomechanisms.

Dataset Information

A MicroRNA Next-Generation-Sequencing Discovery Assay (miND) For Genome-Scale and Absolute Quantitation of Circulating MicroRNA Biomarkers

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