A-to-I RNA editing in the rat brain is age-dependent, region-specific and sensitive to environmental stress across generations

Abstract

BackgroundAdenosine-to-inosine (A-to-I) RNA editing is an epigenetic modification catalyzed by adenosine deaminases acting on RNA (ADARs), and is especially prevalent in the brain. We used the highly accurate microfluidics-based multiplex PCR sequencing (mmPCR-seq) technique to assess the effects of development and environmental stress on A-to-I editing at 146 pre-selected, conserved sites in the rat prefrontal cortex and amygdala. Furthermore, we asked whether changes in editing can be observed in offspring of stress-exposed rats. In parallel, we assessed changes in ADARs expression levels.ResultsIn agreement with previous studies, we found editing to be generally higher in adult compared to neonatal rat brain. At birth, editing was generally lower in prefrontal cortex than in amygdala. Stress affected editing at the serotonin receptor 2c (Htr2c), and editing at this site was significantly altered in offspring of rats exposed to prereproductive stress across two generations. Stress-induced changes in Htr2c editing measured with mmPCR-seq were comparable to changes measured with Sanger and Illumina sequencing. Developmental and stress-induced changes in Adar and Adarb1 mRNA expression were observed but did not correlate with editing changes.ConclusionsOur findings indicate that mmPCR-seq can accurately detect A-to-I RNA editing in rat brain samples, and confirm previous accounts of a developmental increase in RNA editing rates. Our findings also point to stress in adolescence as an environmental factor that alters RNA editing patterns several generations forward, joining a growing body of literature describing the transgenerational effects of stress.Electronic supplementary materialThe online version of this article (10.1186/s12864-017-4409-8) contains supplementary material, which is available to authorized users.

Pre-reproductive stress and fluoxetine treatment in rats affect offspring A-to-I RNA editing, gene expression and social behavior

“…The number of animals per group appears in the figures. Rats were handled in accordance with the NIH guidelines for the Care and Use of Laboratory Animals, 8th edition [ 38 ] and were bred and treated simultaneously to rats described in [ 22 ].…”

“…Using a highly accurate high-throughput targeted approach (microfluidics-based multiplex PCR and deep sequencing—mmPCR-seq [ 26 ]), we recently showed that exposing adolescent female rats to chronic unpredictable stress prior to reproduction (prereproductive stress; PRS) affects A-to-I editing in the prefrontal cortex (PFC) and amygdala of their newborn offspring. In particular, editing at the Htr2c was affected, resulting in a different pattern of Htr2c isoforms in offspring of stress-exposed versus naïve females [ 22 ]. We have previously shown that exposure of adolescent females to PRS also results in changes in behavior, stress-related plasma hormone levels, cortical gene expression and neuronal morphology in first- and second-generation offspring [ 27–31 ].…”

RNA Editing of Serotonin 2C Receptor and Alcohol Intake

“…Moreover, alterations in editing might occur trans-generationally. It was reported that chronic unpredictable stress in pre-reproductive female rats affected the 5-HT 2C R RNA editing in two generations of offspring (Zaidan et al, 2018). Maternal treatment with a serotonin-specific reuptake inhibitor (SSRI), fluoxetine, after stress reversed the effect of these editing changes in the prefrontal cortex and amygdala of new born offspring (Zaidan and Gaisler-Salomon, 2015).…”

Characterizing relevant microRNA editing sites in Parkinson’s disease

“…Parkinson's disease is a neurodegenetative disorder affecting 2-3% of people over 65 years of age [12]. However the functional relevance of miRNA editing in PD is largely unknown, although A-to-I editing is prevalent in brain [13][14][15][16] and the editing level is gradually increasing in the developmental procedure [5,16].To comprehensively characterize miRNA editing sites in brain tissues of PD, we analyzing 43 and 88 small RNA sequencing profiles of PD and control brain tissues, respectively. We identified 421 miRNA editing sites that have significantly different editing levels in prefrontal cortices of PD patients (PD-PC) compared with control group.…”

“…. However the functional relevance of miRNA editing in PD is largely unknown, although A-to-I editing is prevalent in brain [13][14][15][16] and the editing level is gradually increasing in the developmental procedure [5,16].…”