Project description:Elderly patients are apt to cognitive impairment and memory loss after surgical operations. This perioperative cerebral damage named postoperative cognitive dysfunction (POCD) is profoundly affected by anesthesia. N6-methyladenosine (m6A) RNA methylation as a widely-studied epigenetic modification to regulate gene expression, however, is never studied in POCD. Initially, fifty 40-week-old outbred female C57BL/6 mice were conducted Morris water maze test by EthoVision XT working system (Noldus, Netherlands) as manufacturer’s instructions. The escaping latent period of each mouse were recorded. Then Thirty mice were randomly selected and given 2% sevoflurane for 4 h in an automatic anesthetic chamber with size of 24 cm*12 cm*18 cm. After natural resuscitation, POCD and non-POCD mice were picked up based on the dynamics of escaping latent period. The other twenty mice received normal air were treated as negative control. Hippocampus were conducted RIP-seq for investigating m6A RNA methylation.
Project description:We performed RNA sequencing for hippocampus of neonatal mice that were exposed to sevoflurane. We treated a group of neonatal mice with 2.5% sevoflurane for 2 hours on day 6, 7, 8, 9 and treated another group on day 6, 7. On day 36, we collected RNA (both total RNA and polysome-associated RNA) from the hippocampus in the aforementioned two groups and the control group (i.e., without sevoflurane treatment). We prepared the sequencing libraries with the collected RNA and sent them to Illumina sequencing platform.
Project description:Sevoflurane is the most commonly used general anesthetic in pediatric surgery, but it has the potential to be neurotoxic. Previous research found that long-term or multiple sevoflurane exposures could cause cognitive deficits in newborn mice but not adult mice, whereas short-term or single inhalations had little effect on cognitive function at both ages. The mechanisms behind these effects, however, are unclear. In the current study, 6- and 60-day-old C57bl mice in the sevoflurane groups were given 3% sevoflurane plus 60% oxygen for three consecutive days, each lasting 2 hours, while those in the control group only got 60% oxygen. The cortex tissues were harvested on the 8th or 62nd day. The tandem mass tags (TMT)pro-based quantitative proteomics combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysi were applied to analyze the influences of multiple sevoflurane anesthesia on the cerebral cortex in mice with various ages. A total of 6247 proteins were measured using the combined quantitative proteomics methods of TMTpro-labeled and LC-MS/MS, 443 of which were associated to the age-dependent neurotoxic mechanism of repeated sevoflurane anesthesia. Our findings would help to further the mechanistic study of age-dependent anesthetic neurotoxicity and contribute to seek for effective protection in the developing brain under general anesthesia.
Project description:N6-methyladenosine (m6A) is a prevalent and highly regulated RNA modification essential for RNA metabolism and normal brain function. It is particularly important in the hippocampus, where m6A is implicated in neurogenesis and learning. Although extensively studied, its presence and impact in specific cell types remain poorly understood. We investigated m6A in the hippocampus at the single-cell level, revealing a comprehensive landscape of m6A modifications within individual cells.
Project description:Long noncoding RNAs (lncRNAs) play important roles in brain function modulation and neurodegenerative diseases. However, whether lncRNA regulations are involved in the mechanisms of perioperative neurocognitive disorders (PNCD), especially in anesthesia related brain dysfunction, remains unknown. We explored the expression and regulation pattern profiles of lncRNAs in the hippocampus of aged rats after sevoflurane anesthesia with microarrays.
Project description:The focus of current study is to investigate the effect of developing sevoflurane exposure on lncRNA profiles and molecular signaling involvement in neurotoxicity. An Expression Microarray assay (V3.0) and data analysis services were provided by Arraystar Inc. (Rockville, MD) to assess and compare the global abundance of 27,427 lncRNAs and 18,855 mRNAs in the hippocampi of mice exposed to either sevoflurane or normal air controls.
Project description:m6A profiling in two accessions of Arabidopsis thaliana (Can-0 and Hen-16) using the m6A-targeted antibody coupled with high-throughput sequencing m6A-seq in two accessions of Arabidopsis, two replicates for each sample
Project description:Loss-of-function mutations in the gene that encodes TYRO protein kinase-binding protein (TYROBP) cause Nasu-Hakola disease, a heritable disease resembling Alzheimer's disease (AD). Methylation of N6 methyl-adenosine (m6A) in mRNA plays essential roles in learning and memory. Aberrant m6A methylation has been detected in AD patients and animal models. In the present study, Tyrobp−/− mice showed learning and memory deficits in the Morris water maze, which worsened with age. Tyrobp−/− mice also showed elevated levels of total tau, Ser202/Thr205-phosphorylated tau and amyloid β in the hippocampus and cerebrocortex, which worsened with aging. The m6A methyltransferase components METTL3, METTL14, and WTAP were downregulated in Tyrobp−/− mice, while expression of demethylases that remove the m6A modification (e.g., FTO and ALKBH5) were unaltered. Methylated RNA immunoprecipitation sequencing identified 498 m6A peaks that were upregulated in Tyrobp−/− mice, and 312 m6A peaks that were downregulated. Bioinformatic analysis suggested that most of these m6A peaks occur in sequences near stop codons and 3′-untranslated regions. These findings suggest an association between m6A RNA methylation and pathological TYROBP deficiency.
Project description:We performed m6A-RIPs in Ascl1-induced neurons (iNeurons) to investigate the neuronal m6A epitranscriptome. Immunoprecipitation was done twice using two different antibodies, acquired from Abcam and Synaptic Systems (SySy), allowing for a more robust detection of m6A modification marks. Additionally, RIP-seq was performed separately with intact and fragmented RNA. The former approach allowed to identify proportions of m6A-modified transcripts among the total number, while the latter approach provided the information to identify genomic coordinates of m6A peaks.
Project description:XIST is a long non-coding RNA (lncRNA) that mediates transcriptional silencing of X chromosome genes. Here we show that XIST is highly methylated with at least 78 N6-methyladenosine (m6A) residues, a reversible base modification whose function in lncRNAs is unknown. We show that m6A formation in XIST, as well as cellular mRNAs, is mediated by RBM15 and its paralog RBM15B, which bind the m6A-methylation complex and recruit it to specific sites in RNA. This results in methylation of adenosines in adjacent m6A consensus motifs. Furthermore, knockdown of RBM15 and RBM15B, or knockdown of the m6A methyltransferase METTL3 impairs XIST-mediated gene silencing. A systematic comparison of m6A-binding proteins shows that YTHDC1 preferentially recognizes m6A in XIST and is required for XIST function. Additionally, artificial tethering of YTHDC1 to XIST rescues XIST-mediated silencing upon loss of m6A. These data reveal a pathway of m6A formation and recognition required for XIST-mediated transcriptional repression. Three to four biological HEK293T replicates were used to perform iCLIP of endogenous YTH proteins, RBM15, and RBM15B. Crosslinking induced truncations were identified using CIMS-CITS pipeline.