ABSTRACT
BACKGROUND AND AIMS: Pruritus is associated with multiple liver diseases, particularly those with cholestasis, but the mechanism remains incompletely understood. Our aim was to evaluate serum IL-31 as a putative biomarker of pruritus in clinical trials of an farnesoid X receptor (FXR) agonist, cilofexor, in patients with NASH, primary sclerosing cholangitis (PSC), and primary biliary cholangitis (PBC). APPROACH AND RESULTS: Serum IL-31 was measured in clinical studies of cilofexor in NASH, PSC, and PBC. In patients with PSC or PBC, baseline IL-31 was elevated compared to patients with NASH and healthy volunteers (HVs). IL-31 correlated with serum bile acids among patients with NASH, PBC, and PSC. Baseline IL-31 levels in PSC and PBC were positively correlated with Visual Analog Scale for pruritus and 5-D itch scores. In patients with NASH, cilofexor dose-dependently increased IL-31 from Week (W)1 to W24. In patients with NASH receiving cilofexor 100 mg, IL-31 was higher in those with Grade 2-3 pruritus adverse events (AEs) than those with Grade 0-1 pruritus AEs. IL-31 weakly correlated with C4 at baseline in patients with NASH, and among those receiving cilofexor 100 mg, changes in IL-31 and C4 from baseline to W24 were negatively correlated. IL-31 messenger RNA (mRNA) was elevated in hepatocytes from patients with PSC and NASH compared to HVs. In a humanized liver murine model, obeticholic acid increased IL-31 mRNA expression in human hepatocytes and serum levels of human IL-31. CONCLUSIONS: IL-31 levels correlate with pruritus in patients with cholestatic disease and NASH, with FXR agonist therapy resulting in higher serum levels in the latter group. IL-31 appears to derive in part from increased hepatocyte expression. These findings have therapeutic implications for patients with liver disease and pruritus.
Subject(s)
Cholestasis , Liver Cirrhosis, Biliary , Metabolic Diseases , Non-alcoholic Fatty Liver Disease , Humans , Animals , Mice , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/drug therapy , Cholestasis/complications , Cholestasis/drug therapy , Biomarkers , Metabolic Diseases/complications , Pruritus/drug therapy , Pruritus/etiology , Liver Cirrhosis, Biliary/complications , Liver Cirrhosis, Biliary/drug therapyABSTRACT
In response to cold exposure, placental mammals maintain body temperature by increasing sympathetic nerve activity in brown adipose tissue (BAT). Triggering of ß-adrenergic receptors on brown adipocytes stimulates thermogenesis via induction of the cAMP/PKA pathway. Although cAMP response element-binding protein (CREB) and its coactivators-the cAMP-regulated transcriptional coactivators (CRTCs)-mediate transcriptional effects of cAMP in most tissues, other transcription factors such as ATF2 appear critical for induction of thermogenic genes by cAMP in BAT. Brown adipocytes arise from Myf5-positive mesenchymal cells under the control of PRDM16, a coactivator that concurrently represses differentiation along the skeletal muscle lineage. Here, we show that the CREB coactivator CRTC3 is part of an inhibitory feedback pathway that antagonizes PRDM16-dependent differentiation. Mice with a knockout of CRTC3 in BAT (BKO) have increased cold tolerance and reduced adiposity, whereas mice overexpressing constitutively active CRTC3 in adipose tissue are more cold sensitive and have greater fat mass. CRTC3 reduced sympathetic nerve activity in BAT by up-regulating the expression of miR-206, a microRNA that promotes differentiation along the myogenic lineage and that we show here decreases the expression of VEGFA and neurotrophins critical for BAT innervation and vascularization. Sympathetic nerve activity to BAT was enhanced in BKO mice, leading to increases in catecholamine signaling that stimulated energy expenditure. As reexpression of miR-206 in BAT from BKO mice reversed the salutary effects of CRTC3 depletion on cold tolerance, our studies suggest that small-molecule inhibitors against this coactivator may provide therapeutic benefit to overweight individuals.
Subject(s)
Adipose Tissue, Brown/metabolism , Thermogenesis/physiology , Transcription Factors/metabolism , Adipocytes, Brown/metabolism , Adiposity/genetics , Adiposity/physiology , Animals , Cell Differentiation/physiology , Cyclic AMP Response Element-Binding Protein/metabolism , Energy Metabolism , Mice , Mice, Knockout , MicroRNAs/genetics , Signal Transduction , Sympathetic Nervous System/metabolism , Transcription Factors/geneticsABSTRACT
Populations of circulating immune cells are maintained in equilibrium through signals that enhance the retention or egress of hematopoietic stem cells (HSCs) from bone marrow (BM). Prostaglandin E2 (PGE2) stimulates HSC renewal and engraftment through, for example, induction of the cAMP pathway. Triggering of PGE2 receptors increases HSC survival in part via the PKA-mediated induction of the cAMP response element-binding protein (CREB) signaling pathway. PKA stimulates cellular gene expression by phosphorylating CREB at Ser133 and by promoting the dephosphorylation of the cAMP- responsive transcriptional coactivators (CRTCs). We show here that disruption of both CRTC2 and CRTC3 causes embryonic lethality, and that a single allele of either CRTC2 or CRTC3 is sufficient for viability. CRTC2 knockout mice that express one CRTC3 allele (CRTC2/3m mice) develop neutrophilia and splenomegaly in adulthood due to the up-regulation of granulocyte-colony stimulating factor (G-CSF); these effects are reversed following administration of neutralizing anti-G-CSF antiserum. Adoptive transfer of CRTC2/3m BM conferred the splenomegaly/neutrophilia phenotype in WT recipients. Targeted disruption of both CRTC2 and CRTC3 in stromal cells with a mesenchymal Prx1-Cre transgene also promoted this phenotype. Depletion of CRTC2/3 was found to decrease the expression of Suppressor of Cytokine Signaling 3 (SOCS3), leading to increases in STAT3 phosphorylation and to the induction of CEBPß, a key regulator of the G-CSF gene. As small molecule inhibition of JAK activity disrupted CEBPß induction and reduced G-CSF expression in CRTC2/3m stromal cells, our results demonstrate how cross-coupling between the CREB/CRTC and JAK/STAT pathways contributes to BM homeostasis.
Subject(s)
Bone Marrow/physiology , Cyclic AMP Response Element-Binding Protein/metabolism , Hematopoiesis/physiology , Transcription Factors/metabolism , Animals , Bone Marrow Transplantation , Embryonic Development , Gene Expression Regulation, Developmental/physiology , Granulocyte Colony-Stimulating Factor/metabolism , Janus Kinases/genetics , Janus Kinases/metabolism , Mice , Mice, Knockout , NF-kappa B/genetics , NF-kappa B/metabolism , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , Transcription Factors/geneticsABSTRACT
Increases in circulating glucagon during fasting maintain glucose balance by stimulating hepatic gluconeogenesis. Acute ethanol intoxication promotes fasting hypoglycemia through an increase in hepatic NADH, which inhibits hepatic gluconeogenesis by reducing the conversion of lactate to pyruvate. Here we show that acute ethanol exposure also lowers fasting blood glucose concentrations by inhibiting the CREB-mediated activation of the gluconeogenic program in response to glucagon. Ethanol exposure blocked the recruitment of CREB and its coactivator CRTC2 to gluconeogenic promoters by up-regulating ATF3, a transcriptional repressor that also binds to cAMP-responsive elements and thereby down-regulates gluconeogenic genes. Targeted disruption of ATF3 decreased the effects of ethanol in fasted mice and in cultured hepatocytes. These results illustrate how the induction of transcription factors with overlapping specificity can lead to cross-coupling between stress and hormone-sensitive pathways.
Subject(s)
Activating Transcription Factor 3/metabolism , Central Nervous System Depressants/pharmacology , Ethanol/pharmacology , Gluconeogenesis/drug effects , Hepatocytes/metabolism , Liver/metabolism , Activating Transcription Factor 3/genetics , Animals , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/genetics , Cyclic AMP Response Element-Binding Protein/metabolism , Fasting/metabolism , Gluconeogenesis/genetics , Glucose/genetics , Glucose/metabolism , Mice , Mice, Knockout , NADP/genetics , NADP/metabolism , Response Elements , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
In the fasted state, increases in catecholamine signaling promote adipocyte function via the protein kinase A-mediated phosphorylation of cyclic AMP response element binding protein (CREB). CREB activity is further up-regulated in obesity, despite reductions in catecholamine signaling, where it contributes to the development of insulin resistance. Here we show that obesity promotes the CREB binding protein (CBP)-mediated acetylation of CREB at Lys136 in adipose. Under lean conditions, CREB acetylation was low due to an association with the energy-sensing NAD(+)-dependent deacetylase SirT1; amounts of acetylated CREB were increased in obesity, when SirT1 undergoes proteolytic degradation. Whereas CREB phosphorylation stimulated an association with the KIX domain of CBP, Lys136 acetylation triggered an interaction with the CBP bromodomain (BRD) that augmented recruitment of this coactivator to the promoter. Indeed, coincident Ser133 phosphorylation and Lys136 acetylation of CREB stimulated the formation of a ternary complex with the KIX and BRD domains of CBP by NMR analysis. As disruption of the CREB:BRD complex with a CBP-specific BRD inhibitor blocked effects of CREB acetylation on target gene expression, our results demonstrate how changes in nutrient status modulate cellular gene expression in response to hormonal signals.
Subject(s)
Adipocytes/metabolism , Cyclic AMP Response Element-Binding Protein/metabolism , Obesity/metabolism , Signal Transduction , 3T3-L1 Cells , Acetylation , Animals , CREB-Binding Protein/genetics , CREB-Binding Protein/metabolism , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/genetics , Embryo, Mammalian/cytology , Fibroblasts/metabolism , Gene Expression Profiling , HEK293 Cells , Humans , Immunoblotting , Lysine/genetics , Lysine/metabolism , Mice , Mice, Knockout , Mice, Obese , Mutation , Obesity/genetics , Oligonucleotide Array Sequence Analysis , Phosphorylation , Promoter Regions, Genetic/genetics , Protein Binding , Sirtuin 1/genetics , Sirtuin 1/metabolismABSTRACT
The specification of the seven retinal cell types from a common pool of retina progenitor cells (RPCs) involves complex interactions between the intrinsic program and the environment. The proneural basic helix-loop-helix (bHLH) transcriptional regulators are key components for the intrinsic programming of RPCs and are essential for the formation of the diverse retinal cell types. However, the extent to which an RPC can re-adjust its inherent program and the mechanisms through which the expression of a particular bHLH factor influences RPC fate is unclear. Previously, we have shown that Neurod1 inserted into the Atoh7 locus activates the retinal ganglion cell (RGC) program in Atoh7-expressing RPCs but not in Neurod1-expressing RPCs, suggesting that Atoh7-expressing RPCs are not able to adopt the cell fate determined by Neurod1, but rather are pre-programmed to produce RGCs. Here, we show that Neurod1-expressing RPCs, which are destined to produce amacrine and photoreceptor cells, can be re-programmed into RGCs when Atoh7 is inserted into the Neurod1 locus. These results suggest that Atoh7 acts dominantly to convert a RPC subpopulation not destined for an RGC fate to adopt that fate. Thus, Atoh7-expressing and Neurod1-expressing RPCs are intrinsically different in their behavior. Additionally, ChIP-Seq analysis identified an Atoh7-dependent enhancer within the intronic region of Nrxn3. The enhancer recognized and used Atoh7 in the developing retina to regulate expression of Nrxn3, but could be forced to use Neurod1 when placed in a different regulatory context. The results indicate that Atoh7 and Neurod1 activate distinct sets of genes in vivo, despite their common DNA-binding element.
Subject(s)
Amacrine Cells/cytology , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cellular Reprogramming , Nerve Tissue Proteins/metabolism , Retinal Ganglion Cells/cytology , Amacrine Cells/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Cell Differentiation , Chromatin Immunoprecipitation , Electroretinography , Embryo, Mammalian/cytology , Embryo, Mammalian/metabolism , Enhancer Elements, Genetic , Gene Expression Regulation, Developmental , Genetic Loci , Immunohistochemistry , Introns , Mice , Nerve Tissue Proteins/genetics , Photoreceptor Cells/cytology , Photoreceptor Cells/metabolism , Protein Binding , Retina/cytology , Retina/embryology , Retina/metabolism , Retinal Ganglion Cells/metabolism , Stem Cells/cytology , Stem Cells/metabolismABSTRACT
Recognition of modified histone species by distinct structural domains within 'reader' proteins plays a critical role in the regulation of gene expression. Readers that simultaneously recognize histones with multiple marks allow transduction of complex chromatin modification patterns into specific biological outcomes. Here we report that chromatin regulator tripartite motif-containing 24 (TRIM24) functions in humans as a reader of dual histone marks by means of tandem plant homeodomain (PHD) and bromodomain (Bromo) regions. The three-dimensional structure of the PHD-Bromo region of TRIM24 revealed a single functional unit for combinatorial recognition of unmodified H3K4 (that is, histone H3 unmodified at lysine 4, H3K4me0) and acetylated H3K23 (histone H3 acetylated at lysine 23, H3K23ac) within the same histone tail. TRIM24 binds chromatin and oestrogen receptor to activate oestrogen-dependent genes associated with cellular proliferation and tumour development. Aberrant expression of TRIM24 negatively correlates with survival of breast cancer patients. The PHD-Bromo of TRIM24 provides a structural rationale for chromatin activation through a non-canonical histone signature, establishing a new route by which chromatin readers may influence cancer pathogenesis.
Subject(s)
Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Carrier Proteins/metabolism , Gene Expression Regulation, Neoplastic , Histones/metabolism , Acetylation , Breast Neoplasms/pathology , Carrier Proteins/chemistry , Carrier Proteins/genetics , Cell Line, Tumor , Chromatin/metabolism , Chromatin Assembly and Disassembly , Crystallography, X-Ray , Estrogen Receptor alpha/metabolism , Estrogens/metabolism , Gene Expression Regulation, Neoplastic/genetics , HEK293 Cells , Histones/chemistry , Humans , Methylation , Protein Array Analysis , Protein Binding , Protein Structure, Tertiary , Substrate Specificity , Survival RateABSTRACT
Under fasting conditions, increases in circulating glucagon maintain glucose balance by promoting hepatic gluconeogenesis. Triggering of the cAMP pathway stimulates gluconeogenic gene expression through the PKA-mediated phosphorylation of the cAMP response element binding (CREB) protein and via the dephosphorylation of the latent cytoplasmic CREB regulated transcriptional coactivator 2 (CRTC2). CREB and CRTC2 activities are increased in insulin resistance, in which they promote hyperglycemia because of constitutive induction of the gluconeogenic program. The extent to which CREB and CRTC2 are coordinately up-regulated in response to glucagon, however, remains unclear. Here we show that, following its activation, CRTC2 enhances CREB phosphorylation through an association with the protein arginine methyltransferase 5 (PRMT5). In turn, PRMT5 was found to stimulate CREB phosphorylation via increases in histone H3 Arg2 methylation that enhanced chromatin accessibility at gluconeogenic promoters. Because depletion of PRMT5 lowers hepatic glucose production and gluconeogenic gene expression, these results demonstrate how a chromatin-modifying enzyme regulates a metabolic program through epigenetic changes that impact the phosphorylation of a transcription factor in response to hormonal stimuli.
Subject(s)
Energy Metabolism/physiology , Epigenesis, Genetic/physiology , Fasting/physiology , Gene Expression Regulation/physiology , Gluconeogenesis/physiology , Protein-Arginine N-Methyltransferases/metabolism , Animals , Blood Glucose/metabolism , Chromatin Immunoprecipitation , Cyclic AMP Response Element-Binding Protein/metabolism , Electrophoresis, Polyacrylamide Gel , Gene Expression Profiling , HEK293 Cells , Humans , Immunoprecipitation , Luciferases , Mass Spectrometry , Methylation , Mice , Phosphorylation , Transcription Factors/metabolismABSTRACT
Basic leucine zipper (bZip) transcription factors regulate cellular gene expression in response to a variety of extracellular signals and nutrient cues. Although the bZip domain is widely known to play significant roles in DNA binding and dimerization, recent studies point to an additional role for this motif in the recruitment of the transcriptional apparatus. For example, the cAMP response element binding protein (CREB)-regulated transcriptional coactivator (CRTC) family of transcriptional coactivators has been proposed to promote the expression of calcium and cAMP responsive genes, by binding to the CREB bZip in response to extracellular signals. Here we show that the CREB-binding domain (CBD) of CRTC2 folds into a single isolated 28-residue helix that seems to be critical for its interaction with the CREB bZip. The interaction is of micromolar affinity on palindromic and variant half-site cAMP response elements (CREs). The CBD and CREB assemble on the CRE with 2:2:1 stoichiometry, consistent with the presence of one CRTC binding site on each CREB monomer. Indeed, the CBD helix and the solvent-exposed residues in the dimeric CREB bZip coiled-coil form an extended protein-protein interface. Because mutation of relevant bZip residues in this interface disrupts the CRTC interaction without affecting DNA binding, our results illustrate that distinct DNA binding and transactivation functions are encoded within the structural constraints of a canonical bZip domain.
Subject(s)
Cyclic AMP Response Element-Binding Protein/metabolism , Gene Expression Regulation , Transcription Factors/metabolism , Amino Acid Motifs , Amino Acid Sequence , Animals , Conserved Sequence , Crystallography, X-Ray/methods , Cyclic AMP/chemistry , Cysteine/chemistry , DNA/chemistry , Dose-Response Relationship, Drug , HEK293 Cells , Humans , Leucine Zippers , Molecular Sequence Data , Mutation , Protein Binding , Protein Interaction Mapping , Protein Structure, Tertiary , Sequence Homology, Amino Acid , Signal Transduction , Transcriptional ActivationABSTRACT
As neuronal progenitors differentiate into neurons, they acquire a unique set of transcription factors. The transcriptional repressor REST prevents progenitors from undergoing differentiation. Notably, REST binding sites are often associated with retinal ganglion cell (RGC) genes whose expression in the retina is positively controlled by Atoh7, a factor essential for RGC formation. The key regulators that enable a retinal progenitor cell (RPC) to commit to an RGC fate have not been identified. We show here that REST suppresses RGC gene expression in RPCs. REST inactivation causes aberrant expression of RGC transcription factors in proliferating RPCs, independent of Atoh7, resulting in increased RGC formation. Strikingly, inactivating REST in Atoh7-null retinas restores transcription factor expression, which partially activates downstream RGC genes but is insufficient to prevent RGC loss. Our results demonstrate an Atoh7-independent program for initial activation of RGC genes and suggest a novel role for REST in preventing premature expression in RPCs.
Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Differentiation , Gene Expression Regulation, Developmental , Nerve Tissue Proteins/metabolism , Repressor Proteins/metabolism , Retinal Ganglion Cells/cytology , Retinal Ganglion Cells/metabolism , Animals , Base Sequence , Basic Helix-Loop-Helix Transcription Factors/genetics , Female , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Male , Mice , Mice, Inbred C57BL , Mutation , Nerve Tissue Proteins/genetics , Protein Binding , Repressor Proteins/genetics , Transcription Factor Brn-3B/genetics , Transcription Factor Brn-3B/metabolismABSTRACT
BACKGROUND: Katanin p60 is a microtubule-severing protein and is involved in microtubule cytoskeleton organization in both mitotic and non-mitotic processes. Its role in cancer metastasis is unknown. METHODS: Differential protein profiles of bone marrow aspirates were analyzed by chromatography, electrophoresis, and mass spectrometry. Expression of katanin p60 in primary and metastatic prostate cancer was examined by immunohistochemistry. Cellular function of katanin p60 was further examined in prostate cell lines. RESULTS: In a proteomic profiling of bone marrow aspirates from men with prostate cancer, we found that katanin p60 was one of the proteins differentially expressed in bone metastasis samples. Immunohistochemical staining showed that katanin p60 was expressed in the basal cells in normal human prostate glands. In prostatic adenocarcinomas, in which the basal cells were absent, katanin p60 was expressed in the prostate cancer cells. In the specimens from bone metastasis, katanin p60 was detectable in the metastatic cancer cells. Strikingly, some of the metastatic cancer cells also co-expressed basal cell biomarkers including the tumor suppressor p53-homologous protein p63 and the high molecular weight cytokeratins, suggesting that the metastatic prostate cancer cells may have a basal cell-like phenotype. Moreover, overexpression of katanin p60 inhibited prostate cancer cell proliferation but enhanced cell migration activity. CONCLUSIONS: Katanin p60 was aberrantly expressed during prostate cancer progression. Its expression in the metastatic cells in bone was associated with the re-emergence of a basal cell-like phenotype. The elevated katanin p60 expression may contribute to cancer cell metastasis via a stimulatory effect on cell motility.
Subject(s)
Adenocarcinoma/metabolism , Adenocarcinoma/secondary , Adenosine Triphosphatases/metabolism , Bone Neoplasms/metabolism , Bone Neoplasms/secondary , Prostatic Neoplasms/metabolism , Adenocarcinoma/physiopathology , Biomarkers, Tumor/metabolism , Biopsy , Bone Marrow/metabolism , Bone Marrow/pathology , Bone Marrow/physiopathology , Bone Neoplasms/physiopathology , Cell Movement/physiology , Cell Proliferation , Humans , Katanin , Male , Middle Aged , Prostate/metabolism , Prostate/pathology , Prostatic Neoplasms/pathology , Prostatic Neoplasms/physiopathology , Retrospective Studies , Up-RegulationABSTRACT
Numerous studies focus on the tumor suppressor p53 as a protector of genomic stability, mediator of cell cycle arrest and apoptosis, and target of mutation in 50% of all human cancers. The vast majority of information on p53, its protein-interaction partners and regulation, comes from studies of tumor-derived, cultured cells where p53 and its regulatory controls may be mutated or dysfunctional. To address regulation of endogenous p53 in normal cells, we created a mouse and stem cell model by knock-in (KI) of a tandem-affinity-purification (TAP) epitope at the endogenous Trp-53 locus. Mass spectrometry of TAP-purified p53-complexes from embryonic stem cells revealed Tripartite-motif protein 24 (Trim24), a previously unknown partner of p53. Mutation of TRIM24 homolog, bonus, in Drosophila led to apoptosis, which could be rescued by p53-depletion. These in vivo analyses establish TRIM24/bonus as a pathway that negatively regulates p53 in Drosophila. The Trim24-p53 link is evolutionarily conserved, as TRIM24 depletion in human breast cancer cells caused p53-dependent, spontaneous apoptosis. We found that Trim24 ubiquitylates and negatively regulates p53 levels, suggesting Trim24 as a therapeutic target to restore tumor suppression by p53.
Subject(s)
Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitination/genetics , Animals , Apoptosis/genetics , Cell Line, Tumor , Chromatin Immunoprecipitation , Chromatography, Gel , Drosophila , Gene Knock-In Techniques , Humans , Immunoblotting , Mass Spectrometry , Mice , Mutation/genetics , Tumor Suppressor Protein p53/geneticsABSTRACT
UNLABELLED: The p53 family of proteins regulates the expression of target genes that promote cell cycle arrest and apoptosis, which may be linked to cellular growth control as well as tumor suppression. Within the p53 family, p53 and the transactivating p73 isoform (TA-p73) have hepatic-specific functions in development and tumor suppression. Here, we determined TA-p73 interactions with chromatin in the adult mouse liver and found forkhead box O3 (Foxo3) to be one of 158 gene targets. Global profiling of hepatic gene expression in the regenerating liver versus the quiescent liver revealed specific, functional categories of genes regulated over the time of regeneration. Foxo3 is the most responsive gene among transcription factors with altered expression during regenerative cellular proliferation. p53 and TA-p73 bind a Foxo3 p53 response element (p53RE) and maintain active expression in the quiescent liver. During regeneration of the liver, the binding of p53 and TA-p73, the recruitment of acetyltransferase p300, and the active chromatin structure of Foxo3 are disrupted along with a loss of Foxo3 expression. In agreement with the loss of Foxo3 transcriptional activation, a decrease in histone activation marks (dimethylated histone H3 at lysine 4, acetylated histone H3 at lysine 14, and acetylated H4) at the Foxo3 p53RE was detected after partial hepatectomy in mice. These parameters of Foxo3 regulation are reestablished with the completion of liver growth and regeneration and support a temporary suspension of p53 and TA-p73 regulatory functions in normal cells during tissue regeneration. p53-dependent and TA-p73-dependent activation of Foxo3 was also observed in mouse embryonic fibroblasts and in mouse hepatoma cells overexpressing p53, TA-p73alpha, and TA-p73beta isoforms. CONCLUSION: p53 and p73 directly bind and activate the expression of the Foxo3 gene in the adult mouse liver and murine cell lines. p53, TA-p73, and p300 binding and Foxo3 expression decrease during liver regeneration, and this suggests a critical growth control mechanism mediated by these transcription factors in vivo.
Subject(s)
Forkhead Transcription Factors/metabolism , Liver Regeneration/physiology , Liver/metabolism , Nuclear Proteins/metabolism , Tumor Suppressor Protein p53/metabolism , Animals , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Cells, Cultured , Fibroblasts/metabolism , Fibroblasts/pathology , Forkhead Box Protein O3 , Hepatectomy , Histones/metabolism , Liver/pathology , Liver/surgery , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Mice , Mice, Inbred C57BL , Models, Animal , p300-CBP Transcription Factors/metabolismABSTRACT
The alpha-fetoprotein (AFP) gene is highly activated in fetal liver but is dramatically repressed shortly after birth. The mechanisms that underlie AFP transcriptional repression in postpartum liver are not well understood. AFP enhancer, repressor region, and promoter are implicated to be involved in AFP postnatal repression, but the major transcriptional repressor remains undefined. We previously identified a zinc finger protein gene ZBTB20. To determine its physiological functions in vivo, we have generated hepatocyte-specific ZBTB20 knockout mice by the Cre/loxP approach and demonstrated here that ZBTB20 ablation in liver led to dramatic derepression of the AFP gene in entire liver throughout adult life, although the hepatocytes were normally under nonproliferating status. Furthermore, we found that ZBTB20 was a transcriptional repressor capable of specifically inhibiting AFP promoter-driven transcriptional activity. Liver chromatin immunoprecipitation and mobility shift assays showed that ZBTB20 bound to AFP promoter directly. ZBTB20 was developmentally activated in liver after birth and inversely correlated with its AFP gene expression, suggesting that activated ZBTB20 expression in liver mediated AFP gene repression. Our data point to ZBTB20 as a key regulator governing AFP gene transcription and postulate a new model for the postnatal gene repression of AFP in liver.
Subject(s)
Gene Expression Regulation/genetics , Liver/metabolism , Transcription Factors/metabolism , alpha-Fetoproteins/metabolism , Animals , Blotting, Southern , Blotting, Western , Cell Proliferation , Chromatin Immunoprecipitation , Electrophoretic Mobility Shift Assay , Hepatocytes , Immunohistochemistry , Mice , Mice, Knockout , Transcription Factors/geneticsABSTRACT
Three key points of the sit-to-stand (STS) movement were confirmed as aspects of the ground reaction force (GRF): the onset, maximum GRF, and seat-off. 46 healthy subjects (M age = 22.2 yr., SD = 4.4) participated. During the STS movement, two vertical force platforms were used to measure the resultant GRF, defined as the whole-body force, and its two components, the buttock and leg GRFs. The onsets of the component GRFs identified the sequence of the important time points in the STS movement more precisely than the onset of the resultant GRF. Data showed that the maximum whole-body GRF, the maximum GRF of both legs, and seat-off appeared in sequence and not simultaneously.
Subject(s)
Biomechanical Phenomena/physiology , Motor Activity/physiology , Posture/physiology , Weight-Bearing/physiology , Adolescent , Adult , Body Weight/physiology , Buttocks/physiology , Female , Gravitation , Humans , Isometric Contraction/physiology , Leg/physiology , Male , Reaction Time/physiology , Young AdultABSTRACT
The LKB1 tumor suppressor is often mutationally inactivated in non-small cell lung cancer (NSCLC). LKB1 phosphorylates and activates members of the AMPK family of Ser/Thr kinases. Within this family, the salt-inducible kinases (SIKs) modulate gene expression in part via the inhibitory phosphorylation of the CRTCs, coactivators for CREB (cAMP response element-binding protein). The loss of LKB1 causes SIK inactivation and the induction of the CRTCs, leading to the up-regulation of CREB target genes. We identified CRTC2 as a critical factor in LKB1-deficient NSCLC. CRTC2 is unphosphorylated and therefore constitutively activated in LKB1-mutant NSCLC, where it promotes tumor growth, in part via the induction of the inhibitor of DNA binding 1 (ID1), a bona fide CREB target gene. As ID1 expression is up-regulated and confers poor prognosis in LKB1-deficient NSCLC, our results suggest that small molecules that inhibit CRTC2 and ID1 activity may provide therapeutic benefit to individuals with NSCLC.
Subject(s)
Carcinogenesis/metabolism , Carcinoma, Non-Small-Cell Lung/genetics , Cyclic AMP Response Element-Binding Protein/metabolism , Lung Neoplasms/genetics , Mutation/genetics , Protein Serine-Threonine Kinases/genetics , Transcription Factors/metabolism , AMP-Activated Protein Kinase Kinases , Adenocarcinoma of Lung/genetics , Adenocarcinoma of Lung/pathology , Animals , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Cell Proliferation , Female , Gene Expression Regulation, Neoplastic , Humans , Inhibitor of Differentiation Protein 1/metabolism , Lung Neoplasms/pathology , Mice, SCID , Prognosis , Signal TransductionABSTRACT
The aim of this study was to validate the feasibility of a virtual reality-based (without haptic feedback) intravenous injection system as an effective tool for computer-assisted instruction and training. The stability and reliability of the system were assessed. A personal computer, a needle/catheter device, and a data acquisition interface are included in this system. Using Virtual Reality Modeling Language, an interactive virtual environment was developed. Ten participants, ranging from 20 to 28 years of age, were recruited for this study. The self-learning and training procedures encompassed an intravenous catheterization process. The experimental results showed that after a few trials, the change in task time was not obvious in each trial, and the error frequency decreased slightly with more trials. High intraclass correlation coefficients also were obtained for task time and error frequency by analyzing the test-retest reliability. These results indicated that the system was stable and that the system reliability was acceptable.
Subject(s)
Injections, Intravenous , User-Computer Interface , Adult , Computer-Assisted Instruction , Feasibility Studies , Humans , Reproducibility of ResultsABSTRACT
INTRODUCTION: In Taiwan, In Vitro Diagnostic Medical Device (IVD) is regulated as medical device since 1987, and the implementation of IVD registration was fully completed in 2005. The management system of IVD medical device is highly similar with a guidance 'The GHTF Regulatory Model' developed by Global Harmonization Task Force (GHTF) in 2011 for use of regulation development on medical devices. Area covered: In this study, the Regulatory Model developed by GHTF was compared with Taiwanese IVD management system and it has shown that these two regulatory frameworks are highly similar. Expert commentary: The experience of IVD management in Taiwan can serve a strong evidence to prove the feasibility and effectiveness of GHTF Regulatory Model.
Subject(s)
Device Approval , Reagent Kits, Diagnostic , Humans , Models, Theoretical , TaiwanABSTRACT
The mechanisms by which hypoxic tumours evade immunological pressure and anti-tumour immunity remain elusive. Here, we report that two hypoxia-responsive microRNAs, miR-25 and miR-93, are important for establishing an immunosuppressive tumour microenvironment by downregulating expression of the DNA sensor cGAS. Mechanistically, miR-25/93 targets NCOA3, an epigenetic factor that maintains basal levels of cGAS expression, leading to repression of cGAS during hypoxia. This allows hypoxic tumour cells to escape immunological responses induced by damage-associated molecular pattern molecules, specifically the release of mitochondrial DNA. Moreover, restoring cGAS expression results in an anti-tumour immune response. Clinically, decreased levels of cGAS are associated with poor prognosis for patients with breast cancer harbouring high levels of miR-25/93. Together, these data suggest that inactivation of the cGAS pathway plays a critical role in tumour progression, and reveal a direct link between hypoxia-responsive miRNAs and adaptive immune responses to the hypoxic tumour microenvironment, thus unveiling potential new therapeutic strategies.
Subject(s)
Breast Neoplasms/enzymology , MicroRNAs/metabolism , Nucleotidyltransferases/metabolism , Tumor Escape , Adaptive Immunity , Animals , Breast Neoplasms/genetics , Breast Neoplasms/immunology , Breast Neoplasms/pathology , DNA, Mitochondrial/genetics , DNA, Mitochondrial/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Disease Progression , Epigenesis, Genetic , Female , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Humans , MCF-7 Cells , Mice , Mice, Inbred C57BL , Mice, Knockout , MicroRNAs/genetics , Mixed Function Oxygenases/genetics , Mixed Function Oxygenases/metabolism , Nuclear Receptor Coactivator 3/genetics , Nuclear Receptor Coactivator 3/metabolism , Nucleotidyltransferases/genetics , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , RNA Interference , Receptor, Interferon alpha-beta/deficiency , Receptor, Interferon alpha-beta/genetics , Signal Transduction , Time Factors , Transfection , Tumor Hypoxia , Tumor MicroenvironmentABSTRACT
The current study aimed to fabricate three-dimensional (3D) polycaprolactone (PCL), polycaprolactone and ß-tricalcium phosphate (PCL-TCP) scaffolds via a selective laser-sintering technique (SLS). Collagen type I was further coated onto PCL-TCP scaffolds to form PCL-TCP-COL scaffolds. The physical characters of these three scaffolds were analysed. The osteogenic potential of porcine adipose-derived stem cells (pASCs) was compared among these three scaffolds in order to find an optimal scaffold for bone tissue engineering. The experimental results showed no significant differences in pore size and porosity among the three scaffolds; the porosity was ca. 75-77% and the pore size was ca. 300-500 µm in all three. The compressive modulus was increased from 6.77 ± 0.19 to 13.66 ± 0.19 MPa by adding 30% ß-TCP into a 70% PCL scaffold. No significant increase of mechanical strength was found by surface-coating with collagen type I. Hydrophilicity and swelling ratios showed statistical elevation (p < 0.05) after collagen type I was coated onto the PCL-TCP scaffolds. The in vitro study demonstrated that pASCs had the best osteogenic differentiation on PCL-TCP-COL group scaffolds, due to the highest ALP activity, osteocalcin mRNA expression and mineralization. A nude mice experiment showed better woven bone and vascular tissue formation in the PCL-TCP-COL group than in the PCL group. In conclusion, the study demonstrated the ability to fabricate 3D, porous PCL-TCP composite scaffolds (PCL:TCP = 70:30 by weight) via an in-house-built SLS technique. In addition, the osteogenic ability of pASCs was found to be enhanced by coating COL onto the PCL-TCP scaffolds, both in vitro and in vivo. Copyright © 2013 John Wiley & Sons, Ltd.