Liver injury results in rapid regeneration through hepatocyte proliferation and hypertrophy. However, after acute severe injury, such as acetaminophen poisoning, effective regeneration may fail. We investigated how senescence underlies this regenerative failure. In human acute liver disease, and murine models, p21-dependent hepatocellular senescence was proportionate to disease severity and was associated with impaired regeneration. In an acetaminophen injury model a transcriptional signature associated with the induction of paracrine senescence is observed within twenty four hours, and is followed by one of impaired proliferation. In genetic models of hepatocyte injury and senescence we observed transmission of senescence to local uninjured hepatocytes. Spread of senescence depended upon macrophage derived TGFß1 ligand. In acetaminophen poisoning inhibition of TGFß receptor 1 (TGFßR1) improved survival. TGFßR1 inhibition reduced senescence and enhanced liver regeneration even when delivered after the current therapeutic window. This mechanism, in which injury induced senescence impairs regeneration, is an attractive therapeutic target for acute liver failure. Overall design: RNA-seq analysis was performed on a total of 24 samples extracted from murine liver, post hepatic injury induced by acetaminophen administration. Transcriptional profiles were from replicate samples generated at defined timepoints - 12, 24, 36, 48 and 72 hours post injury. Replicate samples were generated from 4 individual animals sacrificed at each timepoint, and compared to a control cohort of 4 animals not subjected to acetaminophen treatment.
TGFβ inhibition restores a regenerative response in acute liver injury by suppressing paracrine senescence.
Specimen part, Cell line, Subject, Time
View SamplesThe chemokine decoy receptor D6 internalises and degrades inflammatory CC chemokines enabling resolution of inflammation. In D6 deficient mice (D6 KO), otherwise innocuous cutaneous inflammatory stimuli induce a grossly exaggerated inflammatory response that bears many similarities to human psoriasis. In the present study we have used transcriptomic approaches to define the molecular make up of this response.
Microarray analyses demonstrate the involvement of type I interferons in psoriasiform pathology development in D6-deficient mice.
Sex, Specimen part, Treatment, Time
View SamplesWe describe a function of focal adhesion kinase (FAK) in driving anti-tumor immune evasion. The kinase activity of nuclear-targeted FAK in squamous cancer cells drives exhaustion of CD8+ T-cells and recruitment of regulatory T-cells by transcriptionally regulating chemokine/cytokine and ligand-receptor networks, including transcription of Ccl5 that is crucial. These changes inhibit antigen-primed cytotoxic CD8+ T-cell activity, permitting growth of FAK-expressing tumors.
Nuclear FAK controls chemokine transcription, Tregs, and evasion of anti-tumor immunity.
Specimen part
View SamplesRare heterozygous coding variants in the triggering receptor expressed in myeloid cells 2 (TREM2) gene, conferring increased risk of developing late-onset Alzheimer''s disease, have been identified. We examined the transcriptional consequences of the loss of Trem2 in mouse brain to better understand its role in disease using differential expression and coexpression network analysis of Trem2 knockout and wild-type mice. We generated RNA-Seq data from cortex and hippocampus sampled at 4 and 8 months. Using brain cell-type markers and ontology enrichment, we found subnetworks with cell type and/or functional identity. We primarily discovered changes in an endothelial gene-enriched subnetwork at 4 months, including a shift toward a more central role for the amyloid precursor protein gene, coupled with widespread disruption of other cell-type subnetworks, including a subnetwork with neuronal identity. We reveal an unexpected potential role of Trem2 in the homeostasis of endothelial cells that goes beyond its known functions as a microglial receptor and signaling hub, suggesting an underlying link between immune response and vascular disease in dementia. Methods: We performed differential expression and co-expression network analysis on a RNA-Seq profiled Trem2 knockout (KO) mouse using two brain areas sampled at 4- and 8-months to obtain a systems level view of the effects of the absence of Trem2. Results: The absence of Trem2 has a stronger effect at an earlier age with the number of differential expressed (DE) genes being 17-fold greater at 4 months than at 8 months in cortex. By integrating DE genes and network analysis, we discovered gene clusters associated with the disruption of blood vessel formation at 4 months of age and protein targeting primarily affecting the hippocampus at 8 months. Further integration of cell type and ontology information revealed a large disruption of a gene module enriched for endothelial cell markers coinciding with the module enriched for neuron cell markers having weaker connections to modules with oligodendrocyte and astrocyte identities. The module with neuronal identity has decreased expression only in the KO where it has closer association with a new module enriched for phagocytic functions. Conclusions: Combining gene co-expression and differential expression analysis on a newly generated RNA-Seq profiled Trem2 KO mouse demonstrate that the absence of Trem2 produces a disruption which mainly affects endothelialon related processes at 4 months of age. It results in a ripple effect that disrupts the cross-talk of other cell types at 8 months, including reduced expression of a gene module enriched in neuron related functions and a shift towards a more central role for App. This study reveals an unexpected role of Trem2 in the homeostasis of endothelial cells that goes beyond its known functions as a microglial receptor and signaling hub suggesting new paths for investigation at the intersection between Trem2, Alzheimer's disease and vascular dementia. Overall design: Hippocampus and cortex were selected because they represent tissues affected in AD at early and late stages, respectively (Matarin 2015, Mastrangelo 2008). Brain tissue samples were obtained from male Trem2 knockout (KO) and wild type (WT) control mice at two time points: 4 months and 8 months. These time points span the onset and late disease stages in well established AD mouse models (Matarin 2015). RNA-Seq was used to profile the transcriptomes for each sample. Two technical replicates were obtained for each sample.
Loss of Trem2 in microglia leads to widespread disruption of cell coexpression networks in mouse brain.
Sex, Specimen part, Subject
View SamplesWe found that the previously published Fmr1 knockout rat model of FXS expresses an Fmr1 transcript with an in-frame deletion of exon 8, which encodes for the K-homology (KH) RNA-binding domain, KH1. We observed that the deletion of exon 8 in 10 male rats within the medial prefrontal cortex (mPFC) led to transcriptional alterations compared to 12 WT rats using RNAseq. Additionally, we used weighted gene co-expression network analysis to generate 23 modules specific to the mPFC with tissue from 35 WT rat samples. Overall design: RNAseq using WT and Fmr1 delta exon 8 mPFC samples
Deletion of the KH1 Domain of Fmr1 Leads to Transcriptional Alterations and Attentional Deficits in Rats.
Age, Specimen part, Cell line, Subject
View Samples