Project description:Background: Obesity is characterized as a disease that directly affects the whole-body metabolism and is associated with excess fat mass and several related comorbidities. Dynamics of the adipocyte hypertrophy and hyperplasia play an important role in health and disease, especially in obesity. Human adipose-derived stem cells (hASC) represent an important source for understanding the entire adipogenic differentiation process. However, little is known about the triggering step of adipogenesis in hASC. Here, we performed a proteogenomic approach for understanding the protein abundance alterations expression changes during the initiation of the adipogenic differentiation process. Methods: hASC were isolated from adipose tissue from three donors, characterized and expanded. Cells were cultured for 24 hours in adipogenic differentiation medium followed to protein extraction. We used shotgun proteomics to compare the proteomic profile of 24h-adipogenic differentiated and undifferentiated hASC. Besides, we used our previously next-generation sequencing data (RNA-seq) from the total and polysomal mRNA fractions of hASC to study post-transcriptional regulation during the initial steps of adipogenesis. Results: We identified a total of 3,.420 proteins out of and 48,.336 peptides, being 92 exclusively identified proteins in the undifferentiated hASC and 53 exclusive proteins in 24h-differentiated cells. Using a stringent criterion, we identified 33 differentially abundant proteins when compare 24h-differentiated versus undifferentiated hASC (14 upregulated and 19 downregulated, respectively). Among the upregulated proteins, we shortlist identified several adipogenic-related proteins. Combined analysis of the proteome and the transcriptome allowed the identification of positive correlation coefficients between proteins and mRNAs. Conclusions: These results demonstrate a specific proteome profile related to adipogenesis at the very beginning (24h) of the differentiation process in hASC, which represents an important piece for a better understanding of human adipogenesis and obesity. In addition, the adipogenic differentiation is fine-tuning regulated at transcriptional, post-transcriptional and post-translational levels.
Project description:Prokaryotic genome annotation is highly dependent on automated methods, as manual curation cannot keep up with the exponential growth of sequenced genomes. Current automated techniques depend heavily on sequence context and often underestimate the complexity of the proteome. We developed REPARATION (RibosomeE Profiling Assisted (Re-)AnnotaTION), a de novo algorithm that takes advantage of experimental evidence from ribosome profiling (Ribo-seq) to delineate translated open reading frames (ORFs) in bacteria, independent of genome annotation. Ribo-seq next generation sequencing technique that provides a genome-wide snapshot of the position translating ribosome along an mRNA at the time of the experiment. REPARATION evaluates all possible ORFs in the genome and estimates minimum thresholds to screen for spurious ORFs based on a growth curve model. We applied REPARATION to three annotated bacterial species to obtain a more comprehensive mapping of their translation landscape in support of experimental data. In all cases, we identified hundreds of novel ORFs including variants of previously annotated and novel small ORFs (<71 codons). Our predictions were supported by matching mass spectrometry (MS) proteomics data and sequence conservation analysis. REPARATION is unique in that it makes use of experimental Ribo-seq data to perform de novo ORF delineation in bacterial genomes, and thus can identify putative coding ORFs irrespective of the sequence context of the reading frame.
Project description:Prokaryotic genome annotation is highly dependent on automated methods, as manual curation cannot keep up with the exponential growth of sequenced genomes. Current automated techniques depend heavily on sequence context and often underestimate the complexity of the proteome. We developed REPARATION (RibosomeE Profiling Assisted (Re-)AnnotaTION), a de novo algorithm that takes advantage of experimental evidence from ribosome profiling (Ribo-seq) to delineate translated open reading frames (ORFs) in bacteria, independent of genome annotation. Ribo-seq next generation sequencing technique that provides a genome-wide snapshot of the position translating ribosome along an mRNA at the time of the experiment. REPARATION evaluates all possible ORFs in the genome and estimates minimum thresholds to screen for spurious ORFs based on a growth curve model. We applied REPARATION to three annotated bacterial species to obtain a more comprehensive mapping of their translation landscape in support of experimental data. In all cases, we identified hundreds of novel ORFs including variants of previously annotated and novel small ORFs (<71 codons). Our predictions were supported by matching mass spectrometry (MS) proteomics data and sequence conservation analysis. REPARATION is unique in that it makes use of experimental Ribo-seq data to perform de novo ORF delineation in bacterial genomes, and thus can identify putative coding ORFs irrespective of the sequence context of the reading frame.
Project description:Here, we compile valuable insights gathered over years of generating Ribo-seq datasets from different plant species and experimental setups. We tested the effects of variable ribonuclease treatments for the generation of ribosome protected fragments (RPFs). We tested rRNA depletion strategies designed specifically for Arabidopsis and Tobacco. We also compare ligation-free to ligation-based library preparation strategies for generating Ribo-seq libraries.
Project description:In this study we aimed to gain further insight on the role of GCs in adipocyte differentiation. For the future drugability of candidate targets it is of utmost importance to find factors relevant to human biology. Thus, we analyzed the transcriptome of GC induced primary human adipose stem cells (hASC) to identify novel factors downstream of GC action We used microarrays to detail the global programme of gene expression following glucocorticoid treatment and identified distinct classes of up- and downregulated genes during this process. Human preadipocytes (human adipose stem cells) were obtained from lipoaspirates by enzamytic digestions, followed by several steps of centrifugations (Mikkelsen et. al Cell. 2010 Oct 1;143(1):156-69.). Following isolation, human adipos estemm cells were treated with Dexamethasone (100nM) for various times.
Project description:The development of the ribosome profiling (ribo-seq) technique has enabled the measurement of translation at a genome-wide level. There are several variants of the ribosome profiling technique that use different translation inhibitors. The regular ribo-seq utilizes Cycloheximide (CHX), a translation elongation inhibitor to freeze all translating ribosomes. In contrast to CHX, the translation inhibitor lactimidomycin (LTM) and harringtonine (Harr) have a much stronger effect on initiating ribosomes. The use of these inhibitors allows for the global mapping of translating initiating sites (TISs) when they are coupled with ribosome profiling (TI-seq). We have developed a computational tool to detect and/or quantitatively compare translation initiation from TI-seq data, and predict novel ORFs from regular CHX-based ribo-seq data. Two replicates of CHX-based ribo-seq experiments and one Harr based ribo-seq were performed in HEK293 cells for confirming the ORFs predicted using public available data.
Project description:In the ribosome complex, tRNA is a critical element of mRNA translation. We reported a new technology for profiling ribosome-embedded tRNAs and their modifications. With the method, we generated a comprehensive survey of the quanity and quality of intra-ribosomal tRNAs (Ribo-tRNA-seq). Ribo-tRNA-seq can provide new insights on translation control mechanism in diverse biological contexts.
Project description:Ribo-T is an engineered ribosome whose small and large subunits are tethered together by insertion of circularly permutated 23S rRNA into 16S rRNA [Orelle, C., Carlson, E. D., Szal, T., Florin, T., Jewett, M. C., Mankin, A.S. Protein synthesis by ribosomes with tethered subunits. Nature 524, 119-124 (2015)]. Whether the growth defects are related to problems with Ribo-T functionality is unclear. The translation in Ribo-T cells was examined by ribosome profiling (Ribo-seq) and RNA sequencing (RNA-seq). Besides the control cells carrying dissociable WT ribosome (SQ171), RIBO-T cells are the original SQ171 strain transformed with pRibo-T plasmid and cured of the plasmid carrying wt rRNA that was evolved to have improved growth characteristics. The Ribo-T strain carries two mutations: a nonsense mutation in the Leu22 codon of the ybeX gene and a missense mutation in codon 549 of the rpsA gene encoding ribosomal protein S1. Analysis of Ribo-T performance by ribosome profiling showed a notably higher ribosome occupancy of the start codons and somewhat increased occupancy at the stop codons of many genes, suggesting that subunit tethering specifically impairs the initiation and termination stages of translation.