ABSTRACT
Low-density lipoprotein receptor-related protein 5 (LRP5) is a constitutively expressed receptor with observed roles in bone homeostasis, retinal development, and cardiac metabolism. However, the function of LRP5 in the brain remains unexplored. This study investigates LRP5's role in the central nervous system by conducting an extensive analysis using RNA-seq tools and in silico assessments. Two protein-coding Lrp5 transcripts are expressed in mice: full-length Lrp5-201 and a truncated form encoded by Lrp5-202. Wt mice express Lrp5-201 in the liver and brain and do not express the truncated form. Lrp5-/- mice express Lrp5-202 in the liver and brain and do not express Lrp5-201 in the liver. Interestingly, Lrp5-/- mouse brains show full-length Lrp5-201 expression, suggesting that LRP5 has a role in preserving brain function during development. Functional gene enrichment analysis on RNA-seq unveils dysregulated expression of genes associated with neuronal differentiation and synapse formation in the brains of Lrp5-/- mice compared to Wt mice. Furthermore, Gene Set Enrichment Analysis highlights downregulated expression of genes involved in retinol and linoleic acid metabolism in Lrp5-/- mouse brains. Tissue-specific alternative splicing of Lrp5 in Lrp5-/- mice supports that the expression of LRP5 in the brain is needed for the correct synthesis of vitamins and fatty acids, and it is indispensable for correct brain development.
Subject(s)
Alternative Splicing , Brain , Low Density Lipoprotein Receptor-Related Protein-5 , Animals , Low Density Lipoprotein Receptor-Related Protein-5/genetics , Low Density Lipoprotein Receptor-Related Protein-5/metabolism , Brain/metabolism , Brain/growth & development , Mice , Mice, Knockout , Liver/metabolism , Liver/growth & development , Mice, Inbred C57BLABSTRACT
BACKGROUND: Nutrient availability during early stages of development (embryogenesis and the first week post-hatch) can have long-term effects on physiological functions and bird metabolism. The embryo develops in a closed structure and depends entirely on the nutrients and energy available in the egg. The aim of this study was to describe the ontogeny of pathways governing hepatic metabolism that mediates many physiological functions in the pHu + and pHu- chicken lines, which are divergently selected for the ultimate pH of meat, a proxy for muscle glycogen stores, and which differ in the nutrient content and composition of eggs. RESULTS: We identified eight clusters of genes showing a common pattern of expression between embryonic day 12 (E12) and day 8 (D8) post-hatch. These clusters were not representative of a specific metabolic pathway or function. On E12 and E14, the majority of genes differentially expressed between the pHu + and pHu- lines were overexpressed in the pHu + line. Conversely, the majority of genes differentially expressed from E18 were overexpressed in the pHu- line. During the metabolic shift at E18, there was a decrease in the expression of genes linked to several metabolic functions (e.g. protein synthesis, autophagy and mitochondrial activity). At hatching (D0), there were two distinct groups of pHu + chicks based on hierarchical clustering; these groups also differed in liver weight and serum parameters (e.g. triglyceride content and creatine kinase activity). At D0 and D8, there was a sex effect for several metabolic pathways. Metabolism appeared to be more active and oriented towards protein synthesis (RPS6) and fatty acid ß-oxidation (ACAA2, ACOX1) in males than in females. In comparison, the genes overexpressed in females were related to carbohydrate metabolism (SLC2A1, SLC2A12, FoxO1, PHKA2, PHKB, PRKAB2 and GYS2). CONCLUSIONS: Our study provides the first detailed description of the evolution of different hepatic metabolic pathways during the early development of embryos and post-hatching chicks. We found a metabolic orientation for the pHu + line towards proteolysis, glycogen degradation, ATP synthesis and autophagy, likely in response to a higher energy requirement compared with pHu- embryos. The metabolic orientations specific to the pHu + and pHu- lines are established very early, probably in relation with their different genetic background and available nutrients.
Subject(s)
Chickens , Liver , Animals , Chickens/genetics , Chickens/growth & development , Chickens/metabolism , Liver/metabolism , Liver/growth & development , Hydrogen-Ion Concentration , Female , Pectoralis Muscles/metabolism , Pectoralis Muscles/growth & development , Male , Gene Expression Profiling , Chick Embryo , Gene Expression Regulation, DevelopmentalABSTRACT
Coordinating epigenomic inheritance and cell cycle progression is essential for organogenesis. UHRF1 connects these functions during development by facilitating maintenance of DNA methylation and cell cycle progression. Here, we provide evidence resolving the paradoxical phenotype of uhrf1 mutant zebrafish embryos which have activation of pro-proliferative genes and increased number of hepatocytes in S-phase, but the liver fails to grow. We uncover decreased Cdkn2a/b and persistent Cdk4/6 activation as the mechanism driving uhrf1 mutant hepatocytes into S-phase. This induces replication stress, DNA damage and Atr activation. Palbociclib treatment of uhrf1 mutants prevented aberrant S-phase entry, reduced DNA damage, and rescued most cellular and developmental phenotypes, but it did not rescue DNA hypomethylation, transposon expression or the interferon response. Inhibiting Atr reduced DNA replication and increased liver size in uhrf1 mutants, suggesting that Atr activation leads to dormant origin firing and prevents hepatocyte proliferation. Cdkn2a/b was downregulated pro-proliferative genes were also induced in a Cdk4/6 dependent fashion in the liver of dnmt1 mutants, suggesting DNA hypomethylation as a mechanism of Cdk4/6 activation during development. This shows that the developmental defects caused by DNA hypomethylation are attributed to persistent Cdk4/6 activation, DNA replication stress, dormant origin firing and cell cycle inhibition.
Subject(s)
Ataxia Telangiectasia Mutated Proteins , Cyclin-Dependent Kinase 4 , Cyclin-Dependent Kinase 6 , DNA Methylation , Liver , Zebrafish , Animals , Ataxia Telangiectasia Mutated Proteins/genetics , Ataxia Telangiectasia Mutated Proteins/metabolism , Cell Cycle/genetics , Cell Cycle Checkpoints/genetics , Cell Division/genetics , Cyclin-Dependent Kinase 4/genetics , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase 6/genetics , Cyclin-Dependent Kinase 6/metabolism , DNA/metabolism , DNA Replication/genetics , Embryo, Nonmammalian , Liver/growth & development , Liver/metabolism , S Phase , Zebrafish/genetics , Zebrafish/metabolism , Enzyme Activation/geneticsABSTRACT
The work aimed to evaluate the weight-length relationship and the condition factor, characterizing the biometry, anatomy, histology and volumetric density of the liver of Brycon amazonicus, in different stages of body growth. The experiment used twenty specimens in four stages of body growth (PI, PII, PIII and PIV) harvested every 90 days, containing five specimens, each group. The livers were dissected, weighed (g) and processed routinely using the hematoxylin and eosin technique. The data were submitted to analysis of variance, Pearson's correlation test and linear regression. The equation that represented the weight-length relation was W = 0.05902 x L2.63, with negative allometric growth, but with a relative condition factor equal to 1.0. The liver was divided into three lobes with the gallbladder close to the right lobe and its color varied from light red to dark red, not varying in relation to other fish species. The hepatosomatic relationship followed body growth until the PII group stage and then declined, demonstrating the behavior of its development in Brycon amazonicus. The organ consists predominantly of hepatocytes, followed by sinusoidal vessels and capillaries, with histological morphology similar to that of many species of fish. Melanomacrophage centers were found only in the most developed animals, but in small quantities, prompting the development of new research on this cell, in this species. In this way, research of this nature allows the characterization of fish species, helping to improve breeding methods, understanding pathological processes caused by diseases, and obtaining better productive capacity, serving an increasingly demanding and prosperous market.
O trabalho objetivou avaliar a relação peso-comprimento e o fator de condição, caracterizando a biometria, anatomia, histologia e densidade volumétrica do fígado de Brycon amazonicus, em diferentes estágios de crescimento corporal. O experimento utilizou vinte espécimes em quatro fases de crescimento corporal (PI, PII, PIII e PIV) colhidos a cada 90 dias, contendo cinco espécimes, cada grupo. Os fígados foram dissecados, pesados (g) e processados rotineiramente pela técnica da hematoxilina e eosina. Os dados foram submetidos à análise de variância, teste de correlação de Pearson e regressão linear. A equação que representou a relação peso-comprimento foi W = 0,05902 x L2,63, com crescimento alométrico negativo, mas com fator de condição relativo igual a 1,0. O fígado apresentou-se dividido em três lobos com a vesícula biliar próxima ao lobo direito e sua cor variou de vermelho claro a vermelho escuro, não variando em relação a outras espécies de peixes. A relação hepatossomática acompanhou o crescimento corporal até a fase do grupo PII e então declinou, demonstrando o comportamento de seu desenvolvimento em Brycon amazonicus. O órgão constitui-se predominantemente por hepatócitos, seguido de vasos e capilares sinusoidais, com a morfologia histológica semelhante ao de muitas espécies de peixes. Centros melanomacrófagos foram encontrados apenas nos animais mais desenvolvidos, mas em pequena quantidade, instigando o desenvolvimento de novas pesquisas sobre esta célula, nesta espécie. Desta forma, pesquisas desta natureza permitem a caracterização de espécies de peixes, auxiliando no aperfeiçoamento de métodos de criação, compreensão de processos patológicos provocados por enfermidades, e obtenção de melhor capacidade produtiva, atendendo um mercado cada vez mais exigente e próspero.
Subject(s)
Animals , Characiformes/growth & development , Liver/anatomy & histology , Liver/growth & developmentABSTRACT
The liver is a pivotal organ regulating critical developmental stages of fetal metabolism and detoxification. Though numerous studies have evaluated links between prenatal/perinatal exposures and adverse health outcomes in the developing fetus, the central role of liver to health disruptions resulting from these exposures remains understudied, especially concerning early development and later-in-life health outcomes. While numerous in vitro methods for evaluating liver toxicity have been established, the use of iPSC-derived hepatocytes appears to be particularly well suited to contribute to this critical research gap due to their potential to model a diverse range of disease phenotypes and different stages of liver development. The following key aspects are reviewed: (1) an introduction to developmental liver toxicity; (2) an introduction to embryonic and induced pluripotent stem cell models; (3) methods and challenges for deriving liver cells from stem cells; and (4) applications for iPSC-derived hepatocytes to evaluate liver developmental stages and their associated responses to insults. We conclude that iPSC-derived hepatocytes have great potential for informing liver toxicity and underlying disease mechanisms via the generation of patient-specific iPSCs; implementing large-scale drug and chemical screening; evaluating general biological responses as a potential surrogate target cell; and evaluating inter-individual disease susceptibility and response variability.
Subject(s)
Induced Pluripotent Stem Cells , Cell Differentiation , Female , Hepatocytes/drug effects , Humans , Induced Pluripotent Stem Cells/metabolism , Liver/drug effects , Liver/growth & development , PregnancyABSTRACT
Zebrafish irf2bp2a, an ortholog of human IRF2BP2, is specifically expressed in the developing liver at growth stage. As a multi-functional protein, the role of irf2bp2a during hepatogenesis remains unclear. Here we take advantage of an irf2bp2a knockout line to show that the deficiency of irf2bp2a can induce apoptosis of hepatic cells through aberrant p53 activation at the early stage of embryonic development. Mechanistic studies reveal that within the IRF2BP2-null hepatic cells, more MDM2 molecules, the E3 ubiquitin ligase of P53, can be sequestrated into the IRF2-MDM2 complex, which in turns stabilizes P53 protein. Moreover, irf2bp2a is demonstrated as a direct downstream target of c/ebpα. Thus, a C/ebpα-Irf2bp2a-P53 axis controls liver development in zebrafish. Overall, our findings indicate a stage-specific role of irf2bp2a on liver organogenesis by regulating p53 pathway.
Subject(s)
Liver , Tumor Suppressor Protein p53 , Zebrafish Proteins , Zebrafish , Animals , Liver/growth & development , Proto-Oncogene Proteins c-mdm2/genetics , Proto-Oncogene Proteins c-mdm2/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Zebrafish/metabolism , Zebrafish Proteins/geneticsABSTRACT
PURPOSE: To evaluate liver function improvement and volume gain after percutaneous recanalization of chronic portal vein thrombosis (PVT) in non-cirrhotic patients. MATERIALS AND METHODS: In this retrospective study, five non-cirrhotic participants between 21 and 67 years old with secondary chronic PVT (4-21 years from diagnose) were submitted to percutaneous portal vein recanalization, followed by varices and shunts embolization. RESULTS: After a mean of 12.6 months, all portal veins remained patent and there was complete resolution of portal hypertension (PH) symptoms in all participants. There was a significant increase in liver volume of 39.8 ± 19.0% (p = 0.042), platelets count of 53120 ± 20188/µl (p = 0.042), and a significant decrease in total bilirubin levels from 1.04 ± 0.23 mg/dL to 0.51 ± 0.09 mg/dL (p = 0.043). We also found a non-significant increase in albumin levels from 3.88 ± 0.39 g/dL to 4.38 ± 0.27 g/dL (p = 0.078) and decrease in spleen diameter from 16.88 ± 4.03 cm to 14.15 ± 2.72 cm (p = 0.068). DISCUSSION: In this retrospective study, even with a small number of participants, we were capable of showing a median of 39.8% increase in liver volume, laboratorial liver function improvement, platelets count and resolution of PH symptoms, including gastroesophageal varices disappearance after portal vein recanalization followed by shunt embolization. CONCLUSION: In this small series of cases, recanalization of chronic PVT in non-cirrhotic participants was feasible, successful and safe despite the prolonged time of occlusion. This is a new and promising approaching to an old and still challenging disease.
Subject(s)
Atherectomy/methods , Hypertension, Portal , Liver/physiology , Portal Vein/physiology , Portasystemic Shunt, Transjugular Intrahepatic , Venous Thrombosis/therapy , Adult , Aged , Humans , Hypertension, Portal/complications , Hypertension, Portal/pathology , Liver/growth & development , Middle Aged , Portal Vein/pathology , Retrospective Studies , Treatment Outcome , Venous Thrombosis/complications , Venous Thrombosis/diagnostic imaging , Young AdultABSTRACT
The postnatal development and maturation of the liver, the major metabolic organ, are inadequately understood. We have analyzed 52,834 single-cell transcriptomes and identified 31 cell types or states in mouse livers at postnatal days 1, 3, 7, 21, and 56. We observe unexpectedly high levels of hepatocyte heterogeneity in the developing liver and the progressive construction of the zonated metabolic functions from pericentral to periportal hepatocytes, which is orchestrated with the development of sinusoid endothelial, stellate, and Kupffer cells. Trajectory and gene regulatory analyses capture 36 transcription factors, including a circadian regulator, Bhlhe40, in programming liver development. Remarkably, we identified a special group of macrophages enriched at day 7 with a hybrid phenotype of macrophages and endothelial cells, which may regulate sinusoidal construction and Treg-cell function. This study provides a comprehensive atlas that covers all hepatic cell types and is instrumental for further dissection of liver development, metabolism, and disease.
Subject(s)
Gene Expression Profiling , Liver/growth & development , Liver/metabolism , Single-Cell Analysis , Animals , Animals, Newborn , Cell Communication , Endothelial Cells/cytology , Endothelial Cells/metabolism , Hematopoiesis , Hepatocytes/cytology , Hepatocytes/metabolism , Macrophages/metabolism , Mesoderm/cytology , RNA-Seq , Time Factors , Transcription Factors/metabolismABSTRACT
Polycystic liver disease (PLD) is a common extrarenal complication of autosomal dominant polycystic kidney disease (ADPKD), which causes compression-related syndrome and ultimately leads to liver dysfunction. Tolvaptan, a V2 receptor antagonist, is widely used to protect kidney function in ADPKD but its effect on PLD remains unknown. An observational cohort study was conducted to evaluate tolvaptan's effect on patients with PLD due to ADPKD. After screening 902 patients, we found the 107 ADPKD patients with PLD who met the criteria of tolvaptan use in Japan. Among them, tolvaptan was prescribed for 62 patients (tolvaptan group), while the other was defined as the non-tolvaptan group. Compared with the non-tolvaptan group, the tolvaptan group had larger height-adjusted total kidney volume (median 994(range 450-4152) mL/m, 513 (405-1928) mL/m, p = 0.01), lower albumin level (mean 3.9±SD 0.4 g/dL, 4.3±0.4g/dL, p<0.01), and higher serum creatinine level (1.2±0.4 mg/dL, 0.9±0.2 mg/dL, p<0.01). Although the median change in annual growth rate of total liver volume (TLV) was not statistically different between the tolvaptan group (-0.8 (-15.9, 16.7) %/year) and the non-tolvaptan group (1.7 (-15.6-18.7) %/year)(p = 0.52), 20 (43.5%) patients in the tolvaptan group experienced a decrease in the growth rate of TLV (responders). A multivariable logistic regression model adjusting for related variables showed that older age (odds ratio 1.15 [95% CI 1.01-1.32]) and a higher growth rate of TLV in the non-tolvaptan period (odds 1.45 95% CI 1.10-1.90) were significantly associated with responders. In conclusion, the change in annual growth rate of TLV in ADPKD patients taking tolvaptan was not statistically different compared with that in ADPKD patients without taking tolvaptan. However, tolvaptan may have the potential to suppress the growth rate of TLV in some PLD patients due to ADPKD, especially in older patients or those that are rapid progressors of PLD. Several limitations were included in this study, therefore well-designed prospective studies were required to confirm the effect of tolvaptan on PLD.
Subject(s)
Antidiuretic Hormone Receptor Antagonists/therapeutic use , Cysts/drug therapy , Kidney/growth & development , Liver Diseases/drug therapy , Liver/growth & development , Polycystic Kidney, Autosomal Dominant/complications , Tolvaptan/therapeutic use , Case-Control Studies , Cysts/etiology , Cysts/pathology , Female , Humans , Kidney/drug effects , Liver/drug effects , Liver Diseases/etiology , Liver Diseases/pathology , Male , Middle Aged , Prognosis , Retrospective StudiesSubject(s)
Bile Ducts, Extrahepatic , Bile Ducts, Intrahepatic , Liver Diseases , Liver Regeneration/physiology , Liver , Animals , Bile Ducts, Extrahepatic/growth & development , Bile Ducts, Extrahepatic/physiology , Bile Ducts, Intrahepatic/growth & development , Bile Ducts, Intrahepatic/physiology , Cell Transdifferentiation/physiology , Humans , Liver/growth & development , Liver/metabolism , Liver/pathology , Liver Diseases/genetics , Liver Diseases/pathology , Liver Diseases/physiopathology , Research , Signal TransductionABSTRACT
Inosine 5'-monophosphate (5'-IMP) is an essential nucleotide for de novo nucleotide biosynthesis and metabolism of energy, proteins, and antioxidants. Nucleotides are conditionally essential, as they cannot be produced sufficiently rapidly to meet the needs of the body in situations of oxidative stress or rapid muscle growth. A deficient intake of nucleotides can result in decreased ATP and GTP synthesis and impaired metabolism. We demonstrated that supplementation of finishing pig diets with 5'-IMP reduces the relative weight of the liver, and increases oxygen consumption during mitochondrial respiration without changing the ADP/O ratio, indicating an increase in the respiratory efficiency of liver mitochondria. We also observed a reduction in liver lipid peroxidation and an increase in muscle creatine. Moreover, 5'IMP supplementation increases slaughter weight, lean meat yield, sarcomere length, and backfat thickness in finishing barrows, demonstrating influence on protein metabolism. We suggest that 5'-IMP supplementation increase the mitochondrial respiratory capacity when the liver metabolic activity is stimulated, enhances antioxidant defense, and promotes muscle growth in finishing barrows.
Subject(s)
Animal Nutritional Physiological Phenomena , Antioxidants/metabolism , Dietary Supplements , Energy Metabolism , Inosine Monophosphate/administration & dosage , Liver/metabolism , Muscle, Skeletal/metabolism , Sus scrofa/metabolism , Animal Feed , Animals , Lipid Peroxidation , Liver/growth & development , Mitochondria, Liver/metabolism , Muscle, Skeletal/growth & development , Oxygen Consumption , Sus scrofa/growth & development , Weight GainABSTRACT
Nanoplastics have raised considerable concerns since their ubiquity in the environment and potential hazard to health. It has been proven that polystyrene nanoparticles (PS-NPs) can be maternally transferred to the offspring. In this study, mice were exposed gestationally and lactationally to PS-NPs (size 100 nm) at different doses (0.1, 1 and 10 mg/L) to investigate the trans-generational poisonousness. Our data illustrated that maternal PS-NPs exposure in pregnancy and lactation resulted in a decline in birth and postnatal body weight in offspring mice. Furthermore, high-dose PS-NPs reduced liver weight, triggered oxidative stress, caused inflammatory cell infiltration, up-regulated proinflammatory cytokine expression, and disturbed glycometabolism in the liver of male offspring mice. In addition, pre- and postnatal PS-NPs exposure diminished testis weight, disrupted seminiferous epithelium and decreased sperm count in mouse offspring. Moreover, PS-NPs induced testicular oxidative injury, as presented by increased malondialdehyde generation and altered superoxide dismutase and catalase activities in the testis of offspring mice. These findings declared that maternal exposure to PS-NPs in pregnancy and lactation can cause hepatic and testicular toxicity in male mouse pups, which put forward new understanding into the detrimental effects of nanoplastics on mammalian offspring.
Subject(s)
Liver/drug effects , Maternal Exposure/adverse effects , Microplastics/toxicity , Polystyrenes/toxicity , Prenatal Exposure Delayed Effects/etiology , Testis/drug effects , Animals , Cytokines/genetics , Cytokines/metabolism , Female , Humans , Infant, Newborn , Lactation , Liver/growth & development , Liver/metabolism , Male , Mice , Nanoparticles/toxicity , Organ Size/drug effects , Oxidative Stress/drug effects , Pedigree , Pregnancy , Prenatal Exposure Delayed Effects/metabolism , Prenatal Exposure Delayed Effects/physiopathology , Testis/growth & development , Testis/metabolismABSTRACT
Aminoacyl tRNA synthetases (ARSs) are a group of proteins, acting as transporters to transfer and attach the appropriate amino acids onto their cognate tRNAs for translation. So far, 18 out of 20 cytoplasmic ARSs are reported to be connected to different neuropathy disorders with multi-organ defects that are often accompanied with developmental delays. Thus, it is important to understand functions and impacts of ARSs at the whole organism level. Here, we systematically analyzed the spatiotemporal expression of 14 ars and 2 aimp genes during development in zebrafish that have not be previously reported. Not only in the brain, their dynamic expression patterns in several tissues such as in the muscles, liver and intestine suggest diverse roles in a wide range of development processes in addition to neuronal function, which is consistent with potential involvement in multiple syndrome diseases associated with ARS mutations. In particular, hinted by its robust expression pattern in the brain, we confirmed that aimp1 is required for the formation of cerebrovasculature by a loss-of-function approach. Overall, our systematic profiling data provides a useful basis for studying roles of ARSs during development and understanding their potential functions in the etiology of related diseases.
Subject(s)
Amino Acyl-tRNA Synthetases/genetics , Gene Expression Regulation, Developmental , Nerve Tissue Proteins/genetics , RNA, Messenger/genetics , RNA, Transfer/genetics , Zebrafish Proteins/genetics , Zebrafish/genetics , Amino Acyl-tRNA Synthetases/classification , Amino Acyl-tRNA Synthetases/metabolism , Animals , Brain/growth & development , Brain/metabolism , Embryo, Nonmammalian , Gene Expression Profiling , Gene Ontology , Humans , Intestines/growth & development , Intestines/metabolism , Liver/growth & development , Liver/metabolism , Molecular Sequence Annotation , Morpholinos/administration & dosage , Morpholinos/genetics , Morpholinos/metabolism , Muscles/metabolism , Nerve Tissue Proteins/classification , Nerve Tissue Proteins/metabolism , Neurodevelopmental Disorders/genetics , Neurodevelopmental Disorders/metabolism , Neurodevelopmental Disorders/pathology , RNA, Messenger/metabolism , RNA, Transfer/metabolism , Zebrafish/growth & development , Zebrafish/metabolism , Zebrafish Proteins/classification , Zebrafish Proteins/metabolismABSTRACT
Nicofluprole is a novel insecticide of the phenylpyrazole class conferring selective antagonistic activity on insect GABA receptors. After repeated daily dietary administration to Wistar rats for 28/90 days, Nicofluprole induced increases in thyroid (and liver) weight, associated with histopathology changes. Nicofluprole did not inhibit thyroid peroxydase nor sodium/iodide symporter, two key players in the biosynthesis of thyroid hormones, indicating the absence of a direct thyroid effect. The results seen in rats suggested a mode of action of Nicofluprole driven by the molecular initiating event of CAR/PXR nuclear receptor activation in livers, with key events of increases in liver weight and hypertrophy, decreasing circulatory thyroid hormones, a compensatory increase in TSH release and follicular cell hypertrophy. To explore the relevance of these changes to humans, well established in vitro rat and human sandwich-cultured hepatocytes were exposed to Nicofluprole up to 7 days. A concentration-dependent CYP3A induction (PXR-activation), an increase in T4-glucuronoconjugation accompanied by UGT1A/2B inductions was observed in rat but not in human hepatocytes. The inductions seen with Nicofluprole in rat (in vivo and in vitro in hepatocytes) that were absent in human hepatocytes represent another example of species-selectivity of nuclear CAR/PXR receptor activators. Importantly, the different pattern observed in rat and human models demonstrate that Nicofluprole-related thyroid effects observed in the rat are with no human relevance.
Subject(s)
Endocrine Disruptors/toxicity , Insecticides/toxicity , Thyroid Gland/drug effects , Animals , Cell Size/drug effects , Hepatocytes/drug effects , Hepatocytes/pathology , Humans , Iodide Peroxidase/metabolism , Liver/drug effects , Liver/growth & development , Organ Size/drug effects , Rats , Rats, Wistar , Species Specificity , Symporters/metabolism , Thyroid Gland/pathology , Thyroid Hormones/blood , Thyrotropin/bloodABSTRACT
Chlorogenic acid (CGA) is a phenylpropanoid compound that is well known to improve the antioxidant capacity and other biological activities. However, the roles of CGA in the liver development of organisms are unclear. In the present study, we aimed to investigate the function of CGA in the hepatic development in thioacetamide (TAA)-induced zebrafish embryos. We found that CGA exerted certain beneficial effects on zebrafish larvae from TAA-exposed zebrafish embryos, such as increasing the liver size, body length, heart rate, acetylcholinesterase activity, and motor ability. In addition, CGA displayed an antioxidant effect on TAA-induced zebrafish embryos by enhancing the activities of superoxide dismutase (SOD), catalase (CAT), and glucose-6-phosphate dehydrogenase (G6PDH), and decreasing of the contents of malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO). The results of western blotting analysis showed that CGA inhibited cell apoptosis by increasing the levels of Bcl2 apoptosis regulator and decreasing the levels of Bcl2 associated X (Bax), apoptosis regulator and tumor protein P53. Moreover, CGA promoted cell proliferation in TAA-induced zebrafish larvae, as detected using proliferating cell nuclear antigen fluorescence immunostaining. In addition, CGA inhibited the expression of Wnt signaling pathway genes Dkk1 (encoding Dickkopf Wnt signaling pathway inhibitors), and promoted the expression of Lef1 (encoding lymphoid enhancer binding factor 1) and Wnt2bb (encoding wingless-type MMTV integration site family, member 2Bb). When the Wnt signal inhibitor IWR-1 was added, there was no significant change in liver development in the IWR-1 + TAA group compared with the IWR-1 + TAA + CGA group (p <0.05), which suggested that CGA regulates liver development via Wnt signaling pathway. Overall, our results suggested that CGA might alleviate TAA-induced toxicity in zebrafish and promote liver development through the Wnt signaling pathway, which provides a basis for the therapeutic effect of CGA on liver dysplasia.
Subject(s)
Chlorogenic Acid/pharmacology , Thioacetamide , Water Pollutants, Chemical , Wnt Signaling Pathway , Acetylcholinesterase/metabolism , Animals , Liver/growth & development , Liver/metabolism , Oxidative Stress , Thioacetamide/toxicity , Water Pollutants, Chemical/toxicity , ZebrafishABSTRACT
BACKGROUND AND AIMS: Alagille Syndrome (ALGS) is a congenital disorder caused by mutations in the Notch ligand gene JAGGED1, leading to neonatal loss of intrahepatic duct (IHD) cells and cholestasis. Cholestasis can resolve in certain patients with ALGS, suggesting regeneration of IHD cells. However, the mechanisms driving IHD cell regeneration following Jagged loss remains unclear. Here, we show that cholestasis due to developmental loss of IHD cells can be consistently phenocopied in zebrafish with compound jagged1b and jagged2b mutations or knockdown. APPROACH AND RESULTS: Leveraging the transience of jagged knockdown in juvenile zebrafish, we find that resumption of Jagged expression leads to robust regeneration of IHD cells through a Notch-dependent mechanism. Combining multiple lineage tracing strategies with whole-liver three-dimensional imaging, we demonstrate that the extrahepatic duct (EHD) is the primary source of multipotent progenitors that contribute to the regeneration, but not to the development, of IHD cells. Hepatocyte-to-IHD cell transdifferentiation is possible but rarely detected. Progenitors in the EHD proliferate and migrate into the liver with Notch signaling loss and differentiate into IHD cells if Notch signaling increases. Tissue-specific mosaic analysis with an inducible dominant-negative Fgf receptor suggests that Fgf signaling from the surrounding mesenchymal cells maintains this extrahepatic niche by directly preventing premature differentiation and allocation of EHD progenitors to the liver. Indeed, transcriptional profiling and functional analysis of adult mouse EHD organoids uncover their distinct differentiation and proliferative potential relative to IHD organoids. CONCLUSIONS: Our data show that IHD cells regenerate upon resumption of Jagged/Notch signaling, from multipotent progenitors originating from an Fgf-dependent extrahepatic stem cell niche. We posit that if Jagged/Notch signaling is augmented, through normal stochastic variation, gene therapy, or a Notch agonist, regeneration of IHD cells in patients with ALGS may be enhanced.
Subject(s)
Alagille Syndrome , Bile Ducts, Extrahepatic , Bile Ducts, Intrahepatic , Calcium-Binding Proteins , Jagged-1 Protein , Liver Regeneration/physiology , Receptors, Notch/metabolism , Zebrafish Proteins , Alagille Syndrome/genetics , Alagille Syndrome/metabolism , Animals , Bile Ducts, Extrahepatic/growth & development , Bile Ducts, Extrahepatic/physiology , Bile Ducts, Intrahepatic/growth & development , Bile Ducts, Intrahepatic/physiology , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , Cell Transdifferentiation , Disease Models, Animal , Humans , Jagged-1 Protein/genetics , Jagged-1 Protein/metabolism , Liver/growth & development , Liver/metabolism , Receptors, Fibroblast Growth Factor/metabolism , Signal Transduction , Zebrafish , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolismABSTRACT
As one of the most metabolically complex systems in the body, the liver ensures multi-organ homeostasis and ultimately sustains life. Nevertheless, during early postnatal development, the liver is highly immature and takes about 2 years to acquire and develop almost all of its functions. Different events occurring at the environmental and cellular levels are thought to mediate hepatic maturation and function postnatally. The crosstalk between the liver, the gut and its microbiome has been well appreciated in the context of liver disease, but recent evidence suggests that the latter could also be critical for hepatic function under physiological conditions. The gut-liver crosstalk is thought to be mediated by a rich repertoire of microbial metabolites that can participate in a myriad of biological processes in hepatic sinusoids, from energy metabolism to tissue regeneration. Studies on germ-free animals have revealed the gut microbiome as a critical contributor in early hepatic programming, and this influence extends throughout life, mediating liver function and body homeostasis. In this seminar, we describe the microbial molecules that have a known effect on the liver and discuss how the gut microbiome and the liver evolve throughout life. We also provide insights on current and future strategies to target the gut microbiome in the context of hepatology research.
Subject(s)
Gastrointestinal Microbiome/physiology , Liver Function Tests/statistics & numerical data , Liver/growth & development , Homeostasis/immunology , Homeostasis/physiology , Humans , Liver/physiology , Liver Function Tests/methodsABSTRACT
Yolk sac (YS) hematopoiesis is critical for the survival of the embryo and a major source of tissue-resident macrophages that persist into adulthood. Yet, the transcriptional and epigenetic regulation of YS hematopoiesis remains poorly characterized. Here we report that the epigenetic regulator Ezh2 is essential for YS hematopoiesis but dispensable for subsequent aorta-gonad-mesonephros (AGM) blood development. Loss of EZH2 activity in hemogenic endothelium (HE) leads to the generation of phenotypically intact but functionally deficient erythro-myeloid progenitors (EMPs), while the generation of primitive erythroid cells is not affected. EZH2 activity is critical for the generation of functional EMPs at the onset of the endothelial-to-hematopoietic transition but subsequently dispensable. We identify a lack of Wnt signaling downregulation as the primary reason for the production of non-functional EMPs. Together, our findings demonstrate a critical and stage-specific role of Ezh2 in modulating Wnt signaling during the generation of EMPs from YS HE.
Subject(s)
Enhancer of Zeste Homolog 2 Protein/genetics , Erythroid Cells/metabolism , Gene Expression Regulation, Developmental , Mouse Embryonic Stem Cells/metabolism , Myeloid Progenitor Cells/metabolism , Vesicular Transport Proteins/genetics , Yolk Sac/metabolism , Animals , Cell Differentiation , Embryo, Mammalian , Enhancer of Zeste Homolog 2 Protein/deficiency , Epigenesis, Genetic , Erythroid Cells/cytology , Female , Fetus , Genes, Reporter , Hematopoiesis/genetics , Liver/cytology , Liver/growth & development , Liver/metabolism , Luminescent Proteins/genetics , Luminescent Proteins/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mouse Embryonic Stem Cells/cytology , Myeloid Progenitor Cells/pathology , Primary Cell Culture , Vesicular Transport Proteins/metabolism , Wnt Signaling Pathway , Yolk Sac/cytology , Yolk Sac/growth & development , Red Fluorescent ProteinABSTRACT
Polyamines (putrescine, spermidine, and spermine) are synthesized primarily from ornithine via ornithine decarboxylase (ODC) in mammals. Although avian tissues contain ODC activity, little is known about intracellular sources of ornithine for their polyamine synthesis. This study tested the hypothesis that arginase and proline oxidase contribute to polyamine synthesis in chickens. Kidney, jejunum, leg muscle, and liver from 0-, 7-, 14- and 21-day-old broiler chickens were assayed for the activities of arginase, proline oxidase (POX), ornithine aminotransferase (OAT), and ornithine decarboxylase (ODC). Kidney slices were also used to determine 14C-polyamine synthesis from [U-14C]arginine and [U-14C]proline. Furthermore, these tissues and plasma were analyzed for polyamines. Results indicate that all tissues contained OAT (mitochondrial) and ODC (cytosolic) activities, but arginase and POX activities were only detected in the mitochondria of chicken kidneys. Renal POX and arginase activities were greater at 7 days of age compared to newly hatched birds, and declined by Day 14. Renal arginase activity was greater at 21 days compared to 14 days of age, but there was no change in renal POX activity during that same period. Concentrations of polyamines in the kidneys and plasma were greater on Day 7 compared to Day 0 and decreased thereafter on Days 14 and 21. Kidney slices readily converted arginine and proline into polyamines, with peak rates being on Day 7. Concentrations of putrescine, spermidine and spermine in the plasma of chickens were about 20- to 100-fold greater than those in mammals. Our results indicate that polyamines are synthesized from arginine and proline in avian kidneys. Unlike mammals, polyamines released from the kidneys are likely the major source of polyamines in the blood and other extra-renal tissues in chickens.