Repetitive sequences derived from transposons make up a large fraction of eukaryotic genomes and must be silenced to protect genome integrity. Repetitive elements are often found in heterochromatin; however, the roles and interactions of heterochromatin proteins in repeat regulation are poorly understood. Here we show that a diverse set of C. elegans heterochromatin proteins act together with the piRNA and nuclear RNAi pathways to silence repetitive elements and prevent genotoxic stress in the germ line. Mutants in genes encoding HPL-2/HP1, LIN-13, LIN-61, LET-418/Mi-2, and H3K9me2 histone methyltransferase MET-2/SETDB1 also show functionally redundant sterility, increased germline apoptosis, DNA repair defects, and interactions with small RNA pathways. Remarkably, fertility of heterochromatin mutants could be partially restored by inhibiting cep-1/p53, endogenous meiotic double strand breaks, or the expression of MIRAGE1 DNA transposons. Functional redundancy among these factors and pathways underlies the importance of safeguarding the genome through multiple means. Overall design: Synchronized, starved L1 stage worms were grown on NGM plates under one of two conditions. Condition 1: growth was at 20°C (hpl-2, let-418, lin-61, met-2 set-25, and wild-type N2) until the L4 stage and then worms were shifted to 25°C for 15-18 hours until they reached young adult stage. Condition 2: growth was at 15°C (lin-13, prg-1, nrde-2, nrde-2; let-418, and wild-type N2) until the L4 stage, and then worms were shifted to 25°C for 15-18 hours until they reached young adult stage. Worms were then washed off plates, flash frozen in liquid nitrogen, and stored at -80°C until use. RNA was extracted from frozen worms using TriPure (Roche). RNA was purified with Zymo Research RNA Clean and Concentrator-5 (Cambridge Bioscience) following DNase I digestion. Ribosomal RNA was depleted using Ribo-Zero rRNA Removal Kit (Human/Mouse/Rat) (Illumina). Libraries were prepared using the NEBNext Ultra Directional RNA Library Prep Kit for Illumina (New England Biolabs). Two biological replicates were prepared for each strain.
A team of heterochromatin factors collaborates with small RNA pathways to combat repetitive elements and germline stress.
Specimen part, Subject
View SamplesIncreased antigen cross-presentation but impaired cross-priming after activation of PPAR is mediated by up-regulation of B7H1
Increased antigen cross-presentation but impaired cross-priming after activation of peroxisome proliferator-activated receptor gamma is mediated by up-regulation of B7H1.
Specimen part
View SamplesThe lower glucose-responsiveness of neonatal beta cells is generally considered a sign of endocrine immaturity. We compared mRNA profiles of neonatal and 10-weeks old rat beta cells to see how their gene expression changes with functional maturation. Neonatal beta cells showed a lower glucose-inducible increment in insulin production than adult cells. This was in part explained by basal protein synthetic hyperactivity of neonatal cells: while at 2.5mM glucose 80% of neonatal beta cells were recruited into active protein synthesis, 10 mM glucose was required to achieve a similar fraction of active adult beta cells. Besides this progressive recruitment, glucose exerted in both age groups an additional amplifying effect in the recruited cells, but clearly more so in adult beta cells that showed a higher maximal synthetic capacity/cell. Neonatal beta cells balanced an advanced endocrine differentiation as judged by their mRNA expression of conserved beta cell marker genes, with higher expression of genes involved in cell cycle and development. One example, Delta-like 1 homolog (DLK1) was used to investigate if neonatal beta cells with basal hyperactivity corresponded to a more immature subset, as marked by high DLK1. Neonatal pancreas contained distinct subsets of DLK1high and DLK1low insulin-expressing cells, but both showed equal hyperactivity. We conclude that neonatal beta cells combine advanced endocrine maturation with traits of residual developmental immaturity. If DLK1 is used as marker for the latter, the basal hyperactivity which proved to be a cardinal feature of neonatal beta cells is not a direct reflection of their residual immaturity.
Functional characteristics of neonatal rat β cells with distinct markers.
Sex, Age, Specimen part
View SamplesAdvanced age is associated with chronic low-grade inflammation, which is usually referred to as inflammaging. Elderly are also known to have an altered gut microbiota composition. However, whether inflammaging is a cause or consequence of an altered gut microbiota composition is not clear. In this study gut microbiota from young or old conventional mice was transferred to young germ-free mice. Four weeks after gut microbiota transfer immune cell populations in spleen, Peyers patches, and mesenteric lymph nodes from conventionalized germ-free mice were analyzed by flow cytometry. In addition, whole-genome gene expression in the ileum was analyzed by microarray. Gut microbiota composition of donor and recipient mice was analyzed with 16S rDNA sequencing. Here we show by transferring aged microbiota to young germ-free mice that certain bacterial species within the aged microbiota promote inflammaging. This effect was associated with lower levels of Akkermansia and higher levels of TM7 bacteria and Proteobacteria in the aged microbiota after transfer. The aged microbiota promoted inflammation in the small intestine in the germ-free mice and enhanced leakage of inflammatory bacterial components into the circulation was observed. Moreover, the aged microbiota promoted increased T cell activation in the systemic compartment. In conclusion, these data indicate that the gut microbiota from old mice contributes to inflammaging after transfer to young germ-free mice.
Aged Gut Microbiota Contributes to Systemical Inflammaging after Transfer to Germ-Free Mice.
Sex, Specimen part, Treatment
View SamplesPurpose:The goals of this study was to determine alterations in expression levels of transcripts downstream of a dominant-negative transcription factor. Quantitative reverse transcription polymerase chain reaction (qRT–PCR) methods was used to confirm the altered expression of targets. Methods: Striatal mRNA profiles of 11-month-old wild-type (WT) and Nestin-Cre X PPAR delta E411P mice were generated by deep sequencing, in triplicate, using Illumina HiSeq 2000. The sequence reads that passed quality filters were analyzed at the transcript isoform level with TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays. Western blots, and immunofluorescence was also used to confirm if altered mRNA levels translated to changes at the protein level. Results: Using data analysis workflow, we mapped sequence reads for each sample to the mouse genome (build mm9) and identified transcripts in the striatum of WT and PPARdelta E411P mice. Conclusions: Our study found multiple transcripts altered in the striatum of the Nestin-Cre x PPAR delta E411P mice as compared to WT striatum, as generated by RNA-SEQ in biologic replicates. Overall design: Striatal mRNA profiles of 11-month-old wild type (WT) and Nestin-Cre X PPAR delta E411P mice were generated by deep sequencing, in triplicate, using Illumina HiSeq2000.
PPAR-δ is repressed in Huntington's disease, is required for normal neuronal function and can be targeted therapeutically.
Specimen part, Cell line, Subject
View SamplesGene Expression Profiling of a Mouse Xenograft Model of Triple-Negative Breast Cancer Brain Metastases With and Without Vorinostat Treatment.
Vorinostat inhibits brain metastatic colonization in a model of triple-negative breast cancer and induces DNA double-strand breaks.
Treatment
View SamplesHigh anaplastic lymphoma kinase (ALK) protein levels may be correlated with an unfavorable prognosis in neuroblastoma (NBL) patients, regardless of ALK mutation status. We therefore examined the correlation between levels of ALK, phosphorylated ALK (pALK) and downstream signaling proteins and response to ALK inhibition in a large panel of both ALK mutated (MUT) and wild type (WT) NBL cell lines. Six of the nineteen NBL cell lines had a point mutation and four an amplification of the ALK gene. ALK amplified cell lines showed similar ALK levels and ALK inhibitor sensitivity as WT cell lines and were therefore co-analyzed. The ALK mRNA (p=0.043), ALK 220 kDa (p=0.009) and ALK 140 kDa (p=0.025) protein levels were higher in ALK mutant (n=6) than WT cell lines (n=13). ALK mRNA and protein levels significantly correlated with ERK1 and ERK2 protein levels, and also with PHOX2B mRNA levels, a neural differentiation marker which is mutated in NBL. Response to ALK inhibitor TAE684 was also significantly correlated with ALK levels. ALK mutant cell lines (n=4) demonstrated a higher sensitivity towards ALK inhibitor TAE684 (14.9 fold more sensitive, p=0.004) than eight WT cell lines. These results underline the importance of ALK mutations but also ALK levels for response to ALK inhibitors in NBL cell lines. Furthermore, the strong correlation of PHOX2B and ALK suggests that neural differentiation stage may be correlated with ALK levels in neuroblastoma. These data will enhance understanding of ALK inhibitor response in future patient trials.
Anaplastic lymphoma kinase (ALK) inhibitor response in neuroblastoma is highly correlated with ALK mutation status, ALK mRNA and protein levels.
Sex, Specimen part
View SamplesC57Bl6J mice were injected CCL4 for 8 weeks to induce liver injury and livers were used to prepare RNA.
Interspecies NASH disease activity whole-genome profiling identifies a fibrogenic role of PPARα-regulated dermatopontin.
Sex, Specimen part, Treatment
View SamplesAnalysis of GPR120 which play roles for the fatty acid sensor in adipose tissue. Results provide insight into the transcriptional effects caused by the loss of the GPR120 proteins and provide further insight into their functions.
Dysfunction of lipid sensor GPR120 leads to obesity in both mouse and human.
Specimen part, Treatment, Subject
View Samples