Autophagy is a mechanism that regulates cellular metabolism and clearance of damaged macromolecules and organelles. Impaired degradation of modified macromolecules contributes to cellular dysfunction and is observed in aged tissue and senescent cells. We have inactivated Atg7, an essential autophagy gene, in murine keratinocytes and have found in an earlier study that this resulted in increased baseline oxidative stress and reduced capacity to degrade crosslinked proteins after oxidative ultraviolet stress. To investigate whether autophagy deficiency would promote cellular aging, we studied, how Atg7 deficient (KO) and Atg7 bearing cells (WT) would respond to stress induced by Paraquat (PQ), an oxidant drug commonly used to induce cellular senescence.
Autophagy deficient keratinocytes display increased DNA damage, senescence and aberrant lipid composition after oxidative stress in vitro and in vivo.
No sample metadata fields
View SamplesLong wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed antioxidant response or Phase II detoxification. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response.
NF-E2-related factor 2 regulates the stress response to UVA-1-oxidized phospholipids in skin cells.
No sample metadata fields
View SamplesPurpose: The phosphoinositide 3-kinase (PI3K) pathway is fundamental for cell proliferation and survival and is frequently altered and activated in neoplasia, including carcinomas of the lung. In this study we investigated the potential of targeting the catalytic class IA PI3K isoforms in small cell lung cancer (SCLC), which is the most aggressive of all lung cancer types. Experimental Design: The expression of PI3K isoforms in patient specimens was analyzed. The effects on SCLC cell survival and downstream signaling were determined following PI3K isoform inhibition by selective inhibitors or down-regulation by small interfering RNA. Results: Over-expression of the PI3K isoforms p110 and p110 was shown by immunohistochemistry in primary SCLC tissue samples. Targeting the PI3K p110 with RNA interference (RNAi) or selective pharmacological inhibitors resulted in strongly affected cell proliferation of SCLC cells in vitro and in vivo, while targeting p110 was less effective. Inhibition of p110 also resulted in increased apoptosis and autophagy, which was accompanied by decreased phosphorylation of Akt and components of the mammalian target of rapamycin (mTOR) pathway, such as the ribosomal S6 protein, and the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). A DNA microarray analysis revealed that p110 inhibition profoundly affected the balance of pro- and anti-apoptotic Bcl-2 family proteins. Finally, p110 inhibition led to impaired SCLC tumor formation and vascularization in vivo. Conclusion: Together our data demonstrate the key involvement of the PI3K isoform p110 in multiple tumor-promoting processes in SCLC.
Targeting the phosphoinositide 3-kinase p110-α isoform impairs cell proliferation, survival, and tumor growth in small cell lung cancer.
Cell line, Treatment
View SamplesThe p53 protein is a cell-autonomous tumor suppressor that restricts malignant transformation by triggering cell cycle exit or apoptosis. p53 also promotes cellular senescence, a program that triggers a stable cell cycle arrest and can modify the tissue microenvironment through its effect on cell membrane and secretory proteins. Here we show that specific ablation of p53 in hepatic stellate cells, which undergo a process of proliferation and senescence in the fibrogenic response to liver damage, enhances liver cirrhosis, reduces survival and increases the malignant transformation of adjacent epithelial cells into hepatocellular carcinoma. This p53-dependent senescence program involves the release of secreted proteins which skew macrophages into a tumor-inhibiting M1-state that can eliminate senescent stellate cells. In contrast, p53-deficient stellate cells secrete factors that promote M2 polarization, which is pro-tumorigenic. Our study reveals that p53 can exert a non-cell-autonomous tumor suppressor response and suggests that this occurs, in part, by its ability to influence macrophage polarization.
Non-cell-autonomous tumor suppression by p53.
Specimen part, Treatment
View SamplesExosomes, endosome-derived membrane microvesicles, contain a specific set of RNA transcripts that are involved in cell-cell communication and hold a great potential as disease biomarkers. To systemically characterize exosomal RNA profiles, we performed RNA sequencing analysis using three human plasma samples and evaluated efficacies of small RNA library preparation protocols from 3 manufacturers. Overall design: We tested the six samples (A1 and A2, B1 and B2, C1 and C2) using two small RNA library preparation kits: NEBNext Multiplex Small RNA library Prep Set from New England Biolab (NEB) and NEXTflex Small RNA Sequencing Kit from Bioo Scientific (BS). We also tested Illumina’s TrueSeq Small RNA Sample Preparation Kit (ILMN) in sample A1 and A2. Together, we tested these plasma samples by sequencing 14 indexed libraries. This study allowed direct comparison of current small RNA library preparation protocols and identified the most suitable strategy for future exosomal RNA sequencing analysis.
Characterization of human plasma-derived exosomal RNAs by deep sequencing.
Specimen part
View SamplesTissue resident memory T cells (TRM) provide superior protection against infection localised to extra-lymphoid compartments in the body. Here we show that CD103+CD8+ TRM cells develop in skin from killer cell lectin-like receptor (KLR)G1-negative precursors that selectively infiltrate the epithelial layer. In the skin, a combination of chemokine-guided epithelial entry, local interleukin (IL)-15 and transforming growth factor (TGF)- signalling is required for formation and survival of these long-lived memory cells. Importantly, TRM differentiation results in the gradual acquisition of a unique transcriptional profile that differs from that expressed by memory cells in the circulation and other types of skin-resident intra-epithelial T cells, such as the dendritic epidermal T cells (DETC). We provide a comprehensive molecular and developmental framework for the local differentiation of a distinct type of peripheral memory T cell that contributes to an important first-line of immune defence in barrier tissues such as skin and mucosa.
The developmental pathway for CD103(+)CD8+ tissue-resident memory T cells of skin.
Specimen part, Time
View SamplesCellular senescence is a homeostatic program associated with tumor suppression, wound healing, and certain age related pathologies. Senescent cells display a repressive chromatin configuration thought to stably silence proliferation-promoting genes, while at the same time activate an unusual form of immune surveillance involving a secretory program referred to as the senescence-associated secretory phenotype (SASP). Here we demonstrate that senescence also involves a global remodeling of the enhancer landscape with recruitment of the chromatin reader BRD4 to newly activated super-enhancers adjacent to key SASP genes. Transcriptional profiling and functional studies indicate that BRD4 is required for the SASP and downstream paracrine signaling. Consequently, BRD4 inhibition disrupts immune cell-mediated targeting and elimination of premalignant senescent cells in vitro and in vivo. Our results identify a critical role for BRD4-bound super-enhancers in senescence immune surveillance and in the proper execution of a tumor-suppressive program. Overall design: Analysis of RNA isolated from human fibroblasts (IMR90) in proliferating, quiescent or senescent (HrasV12) conditions upon knockdown of Brd4, p65, p53, p53/RB, p16/21 or Vehicle and JQ1 treatment
BRD4 Connects Enhancer Remodeling to Senescence Immune Surveillance.
No sample metadata fields
View SamplesIRAK-4 is an essential component of the signal transduction complex downstream of the IL-1- and Toll-like receptors. Though regarded as the first kinase in the signaling cascade, the role of IRAK-4 kinase activity versus its scaffold function is still controversial. In order to investigate the role of IRAK-4 kinase function in vivo, knock-in mice were generated by replacing the wild type IRAK-4 gene with a mutant gene encoding kinase deficient IRAK-4 protein (IRAK-4 KD). Analysis of bone marrow macrophages obtained from WT and IRAK-4 KD mice with a number of experimental techniques demonstrated that the IRAK-4 KD cells greatly lack responsiveness to stimulation with the Toll-like receptor 4 (TLR4) agonist LPS. One of the techniques used, microarray analysis, identified IRAK-4 kinase-dependent LPS response genes and revealed that the induction of LPS-responsive mRNAs was largely ablated in IRAK-4 KD cells. In summary, our results suggest that IRAK-4 kinase activity plays a critical role in TLR4-mediated induction of inflammatory responses.
IRAK-4 kinase activity-dependent and -independent regulation of lipopolysaccharide-inducible genes.
No sample metadata fields
View SamplesNormal human bronchial epithelial cells were studied under four different conditions: control, pressure 30 cmH2O, AG1478 (1 microM), and pressure plus AG1478 at 1, 3, and 8 hours, all in the absence of exogenous EGF.
An EGFR autocrine loop encodes a slow-reacting but dominant mode of mechanotransduction in a polarized epithelium.
Specimen part
View SamplesBiliary atresia (BA) is a rare cholestatic disease of unknown etiology that affects infants and shows an incidence of 1 out of 18,000 live births in Europe (1). The first therapeutic option is a timely performed portoenterostomy. However, the majority of patients suffer from a progressive inflammatory process, which leads to complete destruction of the extra- and intrahepatic biliary system followed by end-stage liver cirrhosis. Hence, BA is the leading indication for pediatric liver transplantation worldwide (2, 3). To understand the pathogenesis of the disease and improve theoutcome of BA patients, research has focused on the inflammatory process in liver and bile ducts, in which several factors are remarkably elevated, such as activated CD4 and CD8 T-cells, TNF alpha,IFN alpha and other proinflammatory TH1 cytokines (3-8). By the time of diagnosis, however, the disease has already reached an advanced state, characterized by the complete obstruction of the extrahepatic bile ducts with impaired bile flow and fibrosis or cirrhosis of the liver. Therefore, studies in humans focusing on the trigger mechanism of BA are limited due to the paucity of liver and availability of bile duct tissue for research. One infectious animal model has been developed, in which newborn Balb/c mice exclusively show the experimental BA phenotype after infection with rhesus rotavirus (RRV) (9, 10). This model allows the analysis of the inflammatory reactions in liver and bile ducts at early steps in the development of bile duct atresia (11-20). Furthermore, inbred mouse strains have been shown to have a different susceptibility for the development of experimental BA, suggesting that Balb/c mice have an immunological gap responsible for disease progression (10, 12). The aim of this study was to identify key genes responsible for the BA phenotype by comparing the transcriptomes at an early time point after virus infection, i.e. before bile duct atresia, between two mouse strains with different susceptibilities to BA. Differences in the virus titration and the clinical course of infected mice were analyzed, and variations in the hepatic gene response assessed by comparative microarray assays were correlated to variances in the hepatic inflammatory reaction.
Susceptibility to experimental biliary atresia linked to different hepatic gene expression profiles in two mouse strains.
Specimen part
View Samples