Transcriptome-wide N6-methyladenine profiling in low input multiplex samples by a kit-free multi-barcode method
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ABSTRACT: N6-methyladnine, which is the most abundant post-transcriptional RNA modification in eukaryotic mRNA, has been proved to be essential in various biological processes and related to numerous diseases. Transcriptome-wide m6A profiling by next generation sequencing is widely used to explore the distributions as well as quantity of m6A modifications. As traditional m6A-seq demands large amount of starting RNA which limited its application to clinical samples, we present a strategy of low input multi-barcode m6A-seq (SLIM-m6A-seq) to realize simplified m6A profiling of mixed clinical samples. This method maintains the advantages of preferable detection limit, low cost and simplified experiment procedures. Sequencing data of clinical blood samples from patients with diabetic myocardial infarction suggest that this method is practical in clinical application and m6A may play a critical role in the progression of diabetic cardiovascular complications.
Project description:Mapping of lamina-associated domains using MadID experiment. A methyltransferase (M.EcoGII) targeted to the nuclear envelope is able to add methyl groups to adenine residues (m6A) on chromatin in contact to the nuclear periphery. A m6A-specific immunoprecipitation is performed on isolated genomic DNA, followed by Ilumina deep sequencing to identify contact sites.
Project description:RNA is subject to a multitude of different chemical modifications that collectively represent the epitranscriptome. Individual RNA modifications including N6-methyladenosine (m6A) on mRNA play essential roles in the posttranscriptional control of gene expression. Recent technological advances have enabled the transcriptome-wide mapping of certain RNA modifications, to reveal their broad relevance and characteristic distribution patterns. However, convenient methods that enable the simultaneous mapping of multiple different RNA marks within the same sample are generally lacking. Here we present EpiPlex RNA modification profiling, a bead-based proximity barcoding assay with sequencing readout that expands the scope of molecular recognition-based RNA modification detection to multiple targets, while providing relative quantification and enabling low RNA input. Measuring signal intensity against spike-in controls provides relative quantification, indicative of the RNA mod abundance at each locus. We report on changes in the modification status of HEK293T cells upon treatment with pharmacological inhibitors separately targeting METTL3, the dominant m6A writer enzyme, and the EIF4A3 component of the exon junction complex (EJC). The treatments resulted in decreased or increased m6A levels, respectively, without effect on inosine levels. Inhibiting the helicase activity of EIF4A3 and EIF4A3 knockdown both cause a significant increase of m6A sites near exon junctions, consistent with the previously reported role of EIF4A3 in shaping the m6A landscape. Thus, EpiPlex offers a reliable and convenient method for simultaneous mapping of multiple RNA modifications to facilitate epitranscriptome studies .
Project description:The detection of hypermethylation markers on cell-free DNA (cfDNA) in biological fluids is a promising and non-invasive approach for early diagnosis and monitoring of human diseases. However, it is challenging to detect hypermethylation markers in a high-throughput, sensitive, and cost-effective manner. Here we presented a multiplex 5-methylcytosine marker barcode counting (MMBC-seq) technique and reported its clinical application for cfDNA from peripheral plasma samples. We identified an MMBC cancer detection panel and developed a scoring system to differentiate cancer versus healthy controls. In a multiple-cancer case-control study, the panel achieved a sensitivity and specificity of 80.2% and 95.7% respectively (AUC 0.906, 95% CI 0.846-0.948). The results suggest that MMBC-seq has great potential to realize non-invasive, flexible and clinically applicable cancer detection.
Project description:In this study, we aimed to systematically profile global RNA N6-methyladenosine (m6A) modification patterns in a mouse model of diabetic cardiomyopathy (DCM). Patterns of m6A in DCM and normal hearts were analyzed via m6A-specific methylated RNA immunoprecipitation followed by high-throughput sequencing (MeRIP-seq) and RNA sequencing (RNA-seq). A total of 973 m6A peaks were detected in DCM samples and 296 differentially methylated sites were selected for further study, including 106 hypermethylated and 190 hypomethylated m6A sites (fold change (FC) > 2, p < 0.05). Gene ontology and KEGG Pathway analyses indicated that unique m6A-modified transcripts in DCM were closely linked to cardiac fibrosis, myocardial hypertrophy, and myocardial energy metabolism. Overall, m6A modification patterns were altered in DCM, and modification of epitranscriptomic processes, such as m6A, is a potentially interesting therapeutic approach.
Project description:We report the application of SMRT seqeuncing from Pacific Biosciences to study the DNA base modifications in dam-/dcm- and wild type E.coli.
Project description:Application of autologous adipose-derived stem cells (ASC) for diabetic chronic wounds has become an emerging treatment option. However, ASCs from diabetic individuals showed impaired cell function and suboptimal wound healing effects. We proposed that adopting a low glucose level in the culture medium for diabetic ASCs may restore their pro-healing capabilities. ASCs from diabetic humans and mice were retrieved and cultured in high-glucose (HG, 4.5 g/L) or low-glucose (LG, 1.0 g/L) conditions. Cell characteristics and functions were investigated in vitro. Moreover, we applied diabetic murine ASCs cultured in HG or LG condition to a wound healing model in diabetic mice to compare their healing capabilities in vivo. Human ASCs exhibited decreased cell proliferation and migration with enhanced senescence when cultured in HG condition in vitro. Similar findings were noted in ASCs derived from diabetic mice. The inferior cellular functions could be partially recovered when they were cultured in LG condition. In the animal study, wounds healed faster when treated with HG or LG-cultured diabetic ASCs relative to the control group. Moreover, higher collagen density, more angiogenesis and cellular retention of applied ASCs were found in wound tissues treated with diabetic ASCs cultured in LG condition. In line with the literature, our study showed that a diabetic milieu exerts an adverse effect on ASCs. Adopting LG culture condition is a simple and effective approach to enhance the wound healing capabilities of diabetic ASCs, which is valuable for the clinical application of autologous ASCs from diabetic patients.
Project description:We developed a simplified proteomics sample preparation method that increased the sensitivity and reproducibility of large-scale plasma samples. Peptide loss was reduced while sensitivity was increased by eliminating the peptide clean-up step and using disposable trap column tips. The simplified High-Throughput Plasma Proteomics (sHTPP) method was evaluated using a systemic approach. We identified and quantified more than 500 proteins in non-depleted plasma samples without missing values as the DIA approach improved in terms of identification and quantification. Furthermore, 96-well plate sample handling with a multi-channel pipet allows for high-throughput sample analysis. In a large-scale clinical trial with 300 plasma samples, we used the method to demonstrate robust and accurate quantifications.
Project description:The results revealed the transcriptional significance of m6A modifications and provide potential therapeutic targets to promote fertility reservation for aging women.
Project description:Monitoring the location of transcription factors (TFs) binding to DNA is key to understanding transcriptional regulation. The main tool for mapping TF binding is ChIP-seq and its variants. However, current ChIP-based methods are hampered by at least one of the following limitations: large input requirements, low spatial resolution, and limited compatibility with high-throughput automation. Here, we describe SLIM-ChIP (Short fragment enriched, Low input, Indexed, MNase ChIP), which overcomes these challenges by combining enzymatic fragmentation of chromatin and on-bead indexing of immobilized TF-DNA complexes. We show that SLIM-ChIP reproduces high resolution binding map of yeast Reb1 similarly to the high-resolution TF mapping methods ChIP-exo and ORGANIC. Yet, SLIM-ChIP requires substantially less input material, and is fully compatible with high-throughput procedures. We further demonstrate the robustness and flexibility of SLIM-ChIP by probing Abf1 and Rap1 in yeast and CTCF in mouse embryonic stem cells. Finally, we show that the unique combination of high resolution and preservation of DNA protection patterns by SLIM-ChIP provide an additional layer of information on the chromatin landscape surrounding the bound TF. We used this information to identify a class of Reb1 sites in which the proximal -1 nucleosome tightly interacts with Reb1 and unlike in most Reb1 sites is refractory to remodeling by the RSC complex. Importantly, the interaction of Reb1 with the -1 nucleosome prevents transcription initiation and can serve as a more general mechanism for maintaining unidirectional transcription. Altogether, SLIM-ChIP is an attractive solution for mapping DNA binding proteins in a more informative context regarding their surrounding chromatin occupancy landscape at a single cell level.
Project description:To identify potential mRNA targets of FTO whose m6A levels are affected by FTO in Diabetic Nephropathy (DN), we conducted m6A-seq for messenger RNAs isolated from HMC cells with and without forced expression of FTO.