Project description:We use ChIP-Seq and RNA-Seq technology to profile the H3K9me2 modification and transcription under different conditions of GLP activity. GLP and G9a are major H3K9 dimethylases, and are essential for mouse early embryonic development. Here we report that GLP and G9a possess intrinsic histone methylation propagating activities. The histone methyltransferase activities of GLP and G9a are stimulated by neighboring nucleosomes pre-methylated at H3K9. These stimulation events function in cis and are dependent on H3K9 methylation binding activities of ankyrin repeats domains in GLP and G9a. In mouse embryonic stem cells (ESCs) harboring a mutant GLP lacking H3K9 methylation propagating activity, pluripotent genes display a delayed kinetics in establishing H3K9 methylation and gene silencing during differentiation. Disruption of the H3K9 methylation propagating activity of GLP in mice causes growth retardation of the embryos, ossification defects of calvaria and early postnatal lethality. We propose that GLP¡¯s ability to rapidly propagate H3K9 methylation is required for efficient gene silencing during programmed cell fate transition. H3K9me2 and H3K9me1 are ChIPped and sequenced in WT mESC and GLP-mutant mESCs, and RNA-Seq was done for those cells as well.
Project description:Glucagon-like peptide-1 (GLP-1) is an incretin hormone that potentiates glucose stimulated insulin secretion. GLP-1 is classically produced by gut L cells; however, under certain circumstances alpha-cells can express the prohormone convertase required for proglucagon processing to GLP-1, prohormone convertase 1/3 (PC1/3), and can produce GLP-1. However, the mechanisms through which this occurs are poorly defined. Understanding the mechanisms by which alpha-cell PC1/3 expression can be activated may reveal new targets for diabetes treatment. Here, we demonstrate that the GLP-1 receptor (GLP-1R) agonist, liraglutide, increases alpha-cell GLP-1 expression in a beta cell GLP-1R-dependent manner. We demonstrate that this effect of liraglutide is translationally relevant in human islets through application of a new scRNA-sequencing technology, DART-seq. We find that the effect of liraglutide to increase alpha-cell PC1/3 mRNA expression occurs in a sub-cluster of alpha-cells and is associated with increased expression of other beta-cell-like genes, which we confirm by IHC. Finally, we find that the effect of liraglutide to increase bi-hormonal insulin+ glucagon+ cells is mediated by the beta-cell GLP-1R in mice. Together, our data validate a new high-sensitivity method for scRNA-sequencing in human islets and identify a novel GLP-1 mediated pathway regulating human alpha-cell function.
Project description:The NLRP3 inflammasome, estrogen and antimicrobial peptides have all been emphasised to have a vital role in the protection of the bladder urothelium. However, the interdependence between these protective factors during a bladder infection is currently unknown. Our aim was to investigate the role of NLRP3 in regulation of antimicrobial peptides and estrogen signaling in bladder epithelial cells during a UPEC infection. Human bladder epithelial cells and CRISPR/Cas9 generated NLRP3-deficient cells were stimulated with the UPEC strain CFT073 and estradiol. The gene and protein expression were evaluated with microarray, qRT-PCR, western blot and ELISA. Microarray results showed that the expression of most antimicrobial peptides was reduced in CFT073-infected NLRP3-deficient cells compared to Cas9 control cells. Conditioned medium from NLRP3-deficient cells also lost the ability to suppress CFT073 growth. Moreover, NLRP3-deficient cells had lower basal release of Beta-defensin-1, Beta-defensin-2 and RNase7. The ability of estradiol to induce an increased expression of antimicrobial peptides was also abrogated in NLRP3-deficient cells. The decreased antimicrobial peptide expression might be linked to the observed reduced expression and activity of estradiol receptor beta in NLRP3-deficient cells. This study suggests that NLRP3 may regulate the release and expression of antimicrobial peptides and affect estrogen signaling in bladder epithelial cells.
Project description:We use ChIP-Seq and RNA-Seq technology to profile the H3K9me2 modification and transcription under different conditions of GLP activity. GLP and G9a are major H3K9 dimethylases, and are essential for mouse early embryonic development. Here we report that GLP and G9a possess intrinsic histone methylation propagating activities. The histone methyltransferase activities of GLP and G9a are stimulated by neighboring nucleosomes pre-methylated at H3K9. These stimulation events function in cis and are dependent on H3K9 methylation binding activities of ankyrin repeats domains in GLP and G9a. In mouse embryonic stem cells (ESCs) harboring a mutant GLP lacking H3K9 methylation propagating activity, pluripotent genes display a delayed kinetics in establishing H3K9 methylation and gene silencing during differentiation. Disruption of the H3K9 methylation propagating activity of GLP in mice causes growth retardation of the embryos, ossification defects of calvaria and early postnatal lethality. We propose that GLP¡¯s ability to rapidly propagate H3K9 methylation is required for efficient gene silencing during programmed cell fate transition.
Project description:To determine the translational status of mRNAs in glp-4 mutant animals, we analyzed total and polysomal RNA levels by tiling arrays A total of 8 samples was analyzed (quadruplicates of glp-4_total and glp-4_polysomal, respectively)
Project description:Aim: The purpose of this RNAseq study is to gain insight into the effect that Glucagon Like Peptide-1(GLP-1) or BMS-21 (11 amino acid GLP-1 mimetic) has on the transcriptomic profile of an insulin secreting pancreatic beta cell line INS-1 at 1h and 6h. Methods: The mRNA-focussed libraries (constructed using TruSeq RNA Library Prep Kit v2) of GLP-1 or BMS-21 treated INS-1 cells at 1h or 6h were generated by sequencing, in quadruplicate, using an Illumina Hiseq2000. De-multiplexing and FASTQ sequence data was generated using the Illumina CASAVA1.8.2 pipeline. The sequence reads that passed quality filters were analyzed at the transcript level using the following. Alignment using TopHat (2.0.12) + Bowtie (2.2.3.0) to the illumina rat iGenome (build 75 - Rnor_5.0 (GCA_000001895.3)), reads summarised using Subread-feature counts (1.4.6) and differential gene analysis using DESeq2 (1.6.3) within Rstudio (0.98.945). Results: GLP-1 treatment of INS-1 cells induced many transcriptomic changes in gene expression at both 1h and 6h relative to control at 1h and 6h. At 1h following GLP-1 treatment there were 674 genes differentially expressed (470 up-regulated and 204 down-regulated, p-adj <0.05). Further, at 6h following exposure to GLP-1 treatment there were 3192 genes differently expressed (1709 up-regulated and 1,483 down-regulated, p-adj <0.05). Comparison of GLP-1 and BMS-21 treatments revealed highly similar transcriptomic profiles at both the 1h and 6h timepoints. Conclusion: GLP-1 has a varied effect on the transcriptomic profile of INS-1 cells.
Project description:GLP-1 induces an increase in heart rate, but its mechanism remains elusive. We used a phosphoproteomic approach to evaluate the effect of GLP-1 on the porcine sinus node. Tissue samples from the sinus node region and left ventricle were collected from eight animals following a 60-minute infusion with either GLP-1 or saline. We employed a tandem mass tag (TMT) labeling strategy to multiplex samples, enriched for phosphorylated peptides by titanium dioxide chromatography, and pre-fractionated the resulting peptide pool prior to LC-MS/MS measurements on an Orbitrap Ascend Tribrid mass spectrometer.