Project description:The Drosophila Taiman (Tai) protein is homologous to the human steroid-receptor coactivators SRC1-3 and activates transcription in complex with the 20-hydroxyecdysone (20E) receptor (EcR). Tai has roles in intestinal homeostasis, germline maintenance, cell motility and proliferation through interactions with EcR and the coactivator Yorkie (Yki). Tai also promotes invasion of tumor cells in adjacent organs, but this pro-invasive mechanism is undefined. Here we show that Tai expression transforms sessile pupal wing cells into an invasive mass that penetrates the adjacent thorax during a period of high 20E. Candidate analysis confirms a reliance on elements of the 20E and Hippo pathways, such as Yki and the Yki-Tai target dilp8. Screening the Tai-induced wing transcriptome detects enrichment for innate immune factors, including the Spätzle (Spz) family of secreted Toll ligands that induce apoptosis during cell competition. Tai-expressing wing cells induce immune signaling and apoptosis among adjacent thoracic cells, and genetic reduction of spz, Toll or the rpr/hid/grim pro-apoptotic factors each suppresses invasion, suggesting an intercellular Spz-Toll circuit supports killing-mediated invasion. Modeling these interactions in larval epithelia confirms that Tai kills neighboring cells via a mechanism involving Toll, Spz factors, and the Spz-inhibitor Necrotic. Tai-expressing cells evade death signals by repressing the immune deficiency (IMD) pathway, which operates in parallel to Toll to control NFkB activity, and independently regulates JNK activity. In sum, these findings suggest that Tai promotes competitive cell killing via Spz-Toll, and that this killing mechanism supports pathologic intertissue invasion in Drosophila.
Project description:The Drosophila Taiman (Tai) protein is homologous to the human steroid-receptor coactivators SRC1-3 and activates transcription in complex with the 20-hydroxyecdysone (20E) receptor (EcR). Tai has roles in intestinal homeostasis, germline maintenance, cell motility, and proliferation through interactions with EcR and the coactivator Yorkie (Yki). Tai also promotes invasion of tumor cells in adjacent organs, but this pro-invasive mechanism is undefined. Here, we show that Tai expression transforms sessile pupal wing cells into an invasive mass that penetrates the adjacent thorax during a period of high 20E. Candidate analysis confirms a reliance on elements of the 20E and Hippo pathways, such as Yki and the Yki-Tai target dilp8. Screening the Tai-induced wing transcriptome detects enrichment for innate immune factors, including the Spätzle (Spz) family of secreted Toll ligands that induce apoptosis during cell competition. Tai-expressing wing cells induce immune signaling and apoptosis among adjacent thoracic cells, and genetic reduction of spz, Toll, or the rpr/hid/grim pro-apoptotic factors each suppresses invasion, suggesting an intercellular Spz-Toll circuit supports killing-mediated invasion. Modeling these interactions in larval epithelia confirms that Tai kills neighboring cells via a mechanism involving Toll, Spz factors, and the Spz inhibitor Necrotic. Tai-expressing cells evade death signals by repressing the immune deficiency (IMD) pathway, which operates in parallel to Toll to control nuclear factor κB (NF-κB) activity and independently regulates JNK activity. In sum, these findings suggest that Tai promotes competitive cell killing via Spz-Toll and that this killing mechanism supports pathologic intertissue invasion in Drosophila.
Project description:Tight regulation of Toll-like receptor (TLR)-mediated inflammatory responses is important in innate immunity. Here, we show that T cell death-associated gene 51 (TDAG51/PHLDA1) is a novel coactivator of the transcription factor FoxO1, regulating inflammatory mediator production in the lipopolysaccharide (LPS)-induced inflammatory response. TDAG51 induction by LPS stimulation was mediated by the TLR2/4 signaling pathway in bone marrow-derived macrophages (BMMs). LPS-induced inflammatory mediator production was significantly decreased in TDAG51-deficient BMMs. In TDAG51-deficient mice, LPS- or pathogenic Escherichia coli infection-induced lethal shock was reduced by decreasing serum proinflammatory cytokine levels. The recruitment of 14-3-3 to FoxO1 was competitively inhibited by the TDAG51-FoxO1 interaction, leading to blockade of FoxO1 cytoplasmic translocation and thereby strengthening FoxO1 nuclear accumulation. TDAG51/FoxO1 double-deficient BMMs showed significantly reduced inflammatory mediator production compared with TDAG51- or FoxO1-deficient BMMs. TDAG51/FoxO1 double deficiency protected mice against LPS- or pathogenic E. coli infection-induced lethal shock by weakening the systemic inflammatory response. Thus, these results indicate that TDAG51 acts as a coactivator of the transcription factor FoxO1, leading to strengthened FoxO1 activity in the LPS-induced inflammatory response.
Project description:In contrast to the well-studied classic MAPKs, such as ERK1/2, little is known concerning the regulation and substrates of the atypical MAPK ERK3 signaling cascade and its function in cancer progression. Here, we report that ERK3 interacted with and phosphorylated steroid receptor coactivator 3 (SRC-3), an oncogenic protein overexpressed in multiple human cancers at serine 857 (S857). This ERK3-mediated phosphorylation at S857 was essential for interaction of SRC-3 with the ETS transcription factor PEA3, which promotes upregulation of MMP gene expression and proinvasive activity in lung cancer cells. Importantly, knockdown of ERK3 or SRC-3 inhibited the ability of lung cancer cells to invade and form tumors in the lung in a xenograft mouse model. In addition, ERK3 was found to be highly upregulated in human lung carcinomas. Our study identifies a previously unknown role for ERK3 in promoting lung cancer cell invasiveness by phosphorylating SRC-3 and regulating SRC-3 proinvasive activity by site-specific phosphorylation. As such, ERK3 protein kinase may be an attractive target for therapeutic treatment of invasive lung cancer.
Project description:The aim of this study is to investigate the interaction between diet - primary meat and fiber - and polymorphisms in Toll-like receptors in relation to risk of colorectal cancer in a Danish prospective cohort.
Project description:Tissue morphogenesis requires the spatial control over actomyosin contractility to drive cell shape changes. How developmental patterning information controls cell mechanics is poorly understood. In the Drosophila embryo ectoderm, Myosin-II is enriched at the interface between antero-posterior neighboring cells, leading to planar polarized cell intercalation. G protein-coupled receptors (GPCRs) are required for planar polarized Myosin-II activation at junctions and Toll receptors provide a positional code underlying this process. How Toll receptors polarize actomyosin contractility remains unknown. Here we report that cells expressing different levels of a single Toll receptor Toll-8 activate Myosin-II at their interface. Surprisingly, the Toll-8 intracellular domain is not required for signaling at cell interfaces suggesting signaling by proxy. We found that Toll-8 forms a molecular complex with the adhesion GPCR Cirl/Latrophilin that is required for Toll-8 dependent junctional Myosin-II activation. Strikingly, the interfaces between Cirl expressing and cirl mutant cells also activate Myosin-II suggesting that Toll-8 induces Cirl asymmetric signaling at cell interfaces. We further showed that Toll-8 recruits Cirl both in trans and in cis, inducing asymmetric Cirl localization at the boundary of the Toll-8 expression domain. Finally, we found that Toll-8 and Cirl exhibit dynamic interdependent planar polarization when neighboring cells express different levels of Toll-8. Through this feedback, Toll-8 and Cirl self-organize planar polarized signaling.
Project description:Toll-like receptors are proteins that play an important role in the innate immune system. They are frequently detected in immune cells such as macrophages or dendritic cells. Their role has been in part studied in prostate cancer. However, in the present study we focus mostly on their functional significance at various types of cancer therapy resistance.
Project description:The rapidly growing family of coregulators of nuclear receptors includes coactivators that promote transcription and corepressors that harbor the opposing function. In recent years, coregulators have begun to emerge as important regulators of metabolic homeostasis, including the p160 Steroid Receptor Coactivator (SRC) family. Members of the SRC family have been ascribed important roles in control of gluconeogenesis in liver and fatty acid oxidation in skeletal muscle. To provide a deeper and more granular understanding of the metabolic impact of SRC family members, we have performed targeted metabolomics analysis of key metabolic byproducts of glucose, fatty acid, and amino acid metabolism in mice with global knockout of SRC-1, SRC-2, or SRC-3. We measured amino acids, acyl carnitines, and organic acids in five tissues with key metabolic functions (liver, heart, skeletal muscle, brain, plasma) isolated from SRC-1, -2, or -3 knockout mice and their wild-type littermates in the fed and fasted conditions, thereby unveiling unique metabolic functions of each SRC coactivator. Overall, we observed entire groups or subgroups of metabolites belonging to discrete metabolic pathways that were influenced in different tissues and/or feeding states due to ablation of individual SRC isoforms. Surprisingly, we identified very few metabolites that changed universally across the three SRC knockout models. These findings demonstrate that coactivator function has very limited redundancy even within the homologous SRC coactivator family. Furthermore, this work also demonstrates the use of metabolomics as a means for identifying novel metabolic regulatory functions of transcriptional coregulators.