Project description:Aging causes a functional decline in tissues throughout the body that may be delayed by caloric restriction (CR). However, the cellular profiles and signatures of aging, as well as those ameliorated by CR, remain unclear. Here, we built comprehensive single-cell and single-nucleus transcriptomic atlases across various rat tissues undergoing aging and CR. CR attenuated aging-related changes in cell type composition, gene expression, and core transcriptional regulatory networks. Immune cells were increased during aging, and CR favorably reversed the aging-disturbed immune ecosystem. Computational prediction revealed that the abnormal cell-cell communication patterns observed during aging, including the excessive proinflammatory ligand-receptor interplay, were reversed by CR. Our work provides multi-tissue single-cell transcriptional landscapes associated with aging and CR in a mammal, enhances our understanding of the robustness of CR as a geroprotective intervention, and uncovers how metabolic intervention can act upon the immune system to modify the process of aging.
Project description:Caloric restriction (CR) extends organismal life- and health-span by improving glucose homeostasis. How CR affect the structure-function of pancreatic beta cells remains unknown. We used single nucleus transcriptomics to show that CR increases the expression of genes for beta cell identity, protein processing, and organelle homeostasis. Gene regulatory network analysis reveal that CR activates transcription factors important for beta cell identity and homeostasis, while imaging metabolomics demonstrates that CR beta cells are more energetically competent. In fact, high-resolution microscopy show that CR reduces beta cell mitophagy to increase mitochondria mass and the potential for ATP generation. However, CR beta cells have impaired adaptive pro liferation in response to high fat diet feeding. Finally, we show that long-term CR delays the onset of beta cell aging and promotes cell longevity by reducing beta cell turnover. Therefore, CR could be a feasible approach to preserve compromised beta cell structure-function during aging and diabetes. 27 diabetes.
Project description:Neurogenesis in the developing neocortex begins with the generation of the preplate, which consists of early-born neurons including Cajal-Retzius (CR) cells and subplate neurons. Here, utilizing the Ebf2-EGFP transgenic mouse in which EGFP initially labels the preplate neurons then persists in CR cells, we reveal the dynamic transcriptome profiles of early neurogenesis and CR cell differentiation. Genome-wide RNA-seq and ChIP-seq analyses at multiple early neurogenic stages have revealed the temporal gene expression dynamics of early neurogenesis and distinct histone modification patterns in early differentiating neurons. We have identified a new set of coding genes and lncRNAs involved in early neuronal differentiation and validated with functional assays in vitro and in vivo. In addition, at E15.5 when Ebf2-EGFP+ cells are mostly CR neurons, single-cell sequencing analysis of purified Ebf2-EGFP+ cells uncovers molecular heterogeneity in CR neurons, but without apparent clustering of cells with distinct regional origins. Along a pseudotemporal trajectory these cells are classified into three different developing states, revealing genetic cascades from early generic neuronal differentiation to late fate specification during the establishment of CR neuron identity and function. Our findings shed light on the molecular mechanisms governing the early differentiation steps during cortical development, especially CR neuron differentiation.
Project description:Clubroot of Brassicaceae, an economically important soil borne disease, is caused by Plasmodiophora brassicae Woronin, an obligate, biotrophic protist. This disease poses a serious threat to canola and related crops in Canada and around the globe causing significant loss to seed yield. The pathogen is continuously evolving and new pathotypes are emerging, this necessitates the development of novel resistant canola cultivars to manage the disease effectively. Given that proteins play a crucial role in majority of biological processes and molecular functions, the identification of differentially abundant proteins (DAP) using proteomics information is an attractive approach to understand the plant-pathogen interactions as well as in the future development of gene specific markers for developing clubroot resistant (CR) cultivars. In this study, P. brassicae pathotype 3 (P3H) was used to challenge CR and clubroot susceptible (CS) canola lines. Root samples were collected at three distinct stages of pathogenesis, 7-, 14-, and 21-days post inoculation (DPI), protein samples were isolated, digested with trypsin and subjected to LC-MS/MS analysis. A total of 937 proteins demonstrated a significant (q < 0.05) change in abundance in at least in one of the time points when compared between control and inoculated CR-parent, CR-progeny, CS-parent, CS-progeny and 784 proteins were significantly (q < 0.05) changed in abundance in at least in one of the time points when compared between the inoculated- CR and CS root proteomes of parent and progeny across the three time points tested. Functional annotation of the differentially abundant proteins (DAPs) revealed several proteins related to calcium dependent signaling pathways in response to the pathogen. In addition, proteins related to reactive oxygen species (ROS) biochemistry, dehydrins, lignin, thaumatin, and phytohormones were identified. Among the DAPs, 74 putative proteins orthologous to CR proteins and quantitative trait loci (QTL) associated with eight CR loci in four chromosomes including chromosomes A3 and A8 were identified. In conclusion, these results have contributed to an improved understanding of the mechanisms that are involved in mediating response to P. brassicae in canola at the protein level.
Project description:Caloric restriction (CR) is the only non-genetic intervention to retard aging and increase longevity in a variety of species. It is important to understand the fundamental mechanism by which CR extends lifespan that remains elusive. Owing to well-established genomic tools and convenience of culture system, we used a single cell organism, Saccharomyces cerevisiae, to clarify the mechanisms of CR. In order to identify genes responsible for CR-mediated longevity, we performed microarray experiments across the longevity assurance time-points.
Project description:Caloric restriction (CR) is the only non-genetic intervention to retard aging and increase longevity in a variety of species. It is important to understand the fundamental mechanism by which CR extends lifespan that remains elusive. Owing to well-established genomic tools and convenience of culture system, we used a single cell organism, Saccharomyces cerevisiae, to clarify the mechanisms of CR. In order to identify genes responsible for CR-mediated longevity, we performed microarray experiments across the longevity assurance time-points. Since the CR-treated cells obtained the longevity potential around 12 hours after inoculation and the strength of potential gradually increased up to 48 hours, we concluded that the changes across these time-points must be a critical need for assurance of longevity by CR. For preparation of total RNA, yeast cells under control (2% glucose) and CR (0.5% glucose) conditions were harvested at 12h, 18h, 24h and 48h after inoculation. After total RNA extraction, we performed Affymetrix Yeast GeneChip 2.0 array for biological triplicate repeats according to the manufacturer's instructions.
Project description:The prime focus of the current therapeutic strategy for Multiple Myeloma (MM) is an early and deep tumour burden reduction; this characterizes and defines the complete response (CR). To date, no description of the characteristics of the plasma cells (PC) prone to achieve CR has been reported. This study aimed at the molecular characterization of PC derived from MM patients who achieved CR after bortezomib-thalidomide-dexamethasone (VTD) first line therapy. One hundred and eighteen MM primary tumours obtained from homogeneously treated patients were globally profiled both for gene expression and for single nucleotide polymorphism genotype. Genomic results were used to obtain a predictor of sensitivity to VTD induction therapy, as well as to describe both the transcription and the genomic profile of PC derived from patients with MM who will respond optimally to primary induction therapy. By analysing the gene profiles of CR patients, we identified a 5-gene signature predicting CR with an overall median accuracy of 75% (range: 72%-85%). In addition, we highlighted the differential expression of a series of genes, whose deregulation, accordingly to their reported functions, might explain the CR patients’ sensitivity to VTD therapy. We also showed that a small copy number loss, covering 606Kb on chromosome 1p22.1 was the most significantly associated with CR patients. The study provides insights into the genomic landscape of PC obtained from newly diagnosed MM patients achieving CR after VTD and shows that patients might be accurately stratified according to their sensitivity to VTD.
Project description:Hundreds of Chromatin Regulators (CRs) control chromatin structure and function by catalyzing and binding histone modifications, yet the rules governing these key processes remain obscure. Here, we present a systematic approach to infer CR function. We developed ChIP-string, a meso-scale assay that combines chromatin immunoprecipitation with a signature readout of 487 representative loci. We applied ChIP-string to screen 145 antibodies, thereby identifying effective reagents, which we used to map the genome-wide binding of 29 CRs in two cell types. We found that specific combinations of CRs co-localize in characteristic patterns at distinct chromatin environments, genes of coherent functions and distal regulatory elements. When comparing between cell types, CRs redistribute to different loci, but maintain their modular and combinatorial associations. Our work provides a multiplex method that substantially enhances the ability to monitor CR binding, presents a large resource of CR maps, and reveals common principles for combinatorial CR function. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Study of genom-wide binding of 29 CRs in two cell types.