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1.
Eur J Drug Metab Pharmacokinet ; 49(3): 393-403, 2024 May.
Article En | MEDLINE | ID: mdl-38642299

BACKGROUND AND OBJECTIVE: The prediction of pharmacokinetic parameters for drugs metabolised by cytochrome P450 enzymes has been the subject of active research for many years, while the application of in vitro-in vivo extrapolation (IVIVE) techniques for non-cytochrome P450 enzymes has not been thoroughly evaluated. There is still no established quantitative method for predicting hepatic clearance of drugs metabolised by uridine 5'-diphospho-glucuronosyltransferases (UGTs), not to mention those which undergo hepatic uptake. The objective of the study was to predict the human hepatic clearance for telmisartan based on in vitro metabolic stability and hepatic uptake results. METHODS: Telmisartan was examined in liver systems, allowing to estimate intrinsic clearance (CLint, in vitro) based on the substrate disappearance rate with the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) technique. Obtained CLint, in vitro values were corrected for corresponding unbound fractions. Prediction of human hepatic clearance was made from scaled unbound CLint, in vitro data with the use of the well-stirred model, and finally referenced to the literature value of observed clearance in humans, allowing determination of the essential scaling factors. RESULTS: The in vitro scaled CLint, in vitro by UGT1A3 was assessed using three systems, human hepatocytes, liver microsomes, and recombinant enzymes. Obtained values were scaled and hepatic metabolism clearance was predicted, resulting in significant clearance underprediction. Utilization of the extended clearance concept (ECC) and hepatic uptake improved prediction of hepatic metabolism clearance. The scaling factors for hepatocytes, assessing the in vitro-in vivo difference, changed from sixfold difference to only twofold difference with the application of the ECC. CONCLUSIONS: The study showed that taking into consideration hepatic uptake of a drug allows us to obtain satisfactory scaling factors, hence enabling the prediction of in vivo hepatic glucuronidation from in vitro data.


Glucuronides , Glucuronosyltransferase , Microsomes, Liver , Solute Carrier Organic Anion Transporter Family Member 1B3 , Telmisartan , Glucuronosyltransferase/metabolism , Telmisartan/pharmacokinetics , Telmisartan/metabolism , Humans , Microsomes, Liver/metabolism , Glucuronides/metabolism , Solute Carrier Organic Anion Transporter Family Member 1B3/metabolism , Liver/metabolism , Liver/enzymology , Metabolic Clearance Rate , Tandem Mass Spectrometry/methods , Hepatocytes/metabolism , Models, Biological , Chromatography, Liquid/methods , Benzoates/pharmacokinetics , Benzoates/metabolism
2.
Environ Sci Process Impacts ; 26(4): 765-777, 2024 Apr 24.
Article En | MEDLINE | ID: mdl-38517292

Background: Growing evidence has demonstrated the role of ambient air pollutants in driving diabetes incidence. However, epidemiological evidence linking ozone (O3) exposure to diabetes risk has been scarcely studied in Zhuang adults in China. We aimed to investigate the associations of long-term exposure to O3 with diabetes prevalence and fasting plasma glucose (FPG) and estimate the mediating role of liver enzymes in Zhuang adults. Methods: We recruited 13 843 ethnic minority adults during 2018-2019 based on a cross-sectional study covering nine districts/counties in Guangxi. Generalized linear mixed models were implemented to estimate the relationships between O3 exposure and diabetes prevalence and FPG. Mediation effect models were constructed to investigate the roles of liver enzymes in the associations of O3 exposure with diabetes prevalence and FPG. Subgroup analyses were conducted to identify potential effect modifications. Results: Long-term exposure to O3 was positively associated with diabetes prevalence and FPG levels in Zhuang adults, with an excess risk of 7.32% (95% confidence interval [CI]: 2.56%, 12.30%) and an increase of 0.047 mmol L-1 (95% CI: 0.032, 0.063) for diabetes prevalence and FPG levels, respectively, for each interquartile range (IQR, 1.18 µg m-3) increment in O3 concentrations. Alanine aminotransferase (ALT) significantly mediated 8.10% and 29.89% of the associations of O3 with FPG and diabetes prevalence, respectively, and the corresponding mediation proportions of alkaline phosphatase (ALP) were 8.48% and 30.00%. Greater adverse effects were observed in females, obese subjects, people with a low education level, rural residents, non-clean fuel users, and people with a history of stroke and hypertension in the associations of O3 exposure with diabetes prevalence and/or FPG levels (all P values for interaction < 0.05). Conclusion: Long-term exposure to O3 is related to an increased risk of diabetes, which is partially mediated by liver enzymes in Chinese Zhuang adults. Promoting clean air policies and reducing exposure to environmental pollutants should be a priority for public health policies geared toward preventing diabetes.


Air Pollutants , Diabetes Mellitus , Environmental Exposure , Liver , Ozone , Humans , Ozone/adverse effects , Ozone/analysis , Cross-Sectional Studies , China/epidemiology , Male , Female , Adult , Diabetes Mellitus/epidemiology , Middle Aged , Environmental Exposure/statistics & numerical data , Environmental Exposure/adverse effects , Air Pollutants/analysis , Air Pollutants/adverse effects , Liver/enzymology , Prevalence , Blood Glucose/analysis
3.
J Biol Chem ; 300(3): 105724, 2024 Mar.
Article En | MEDLINE | ID: mdl-38325742

Mammalian cells have evolved strategies to regulate gene expression when oxygen is limited. Hypoxia-inducible factors (HIF) are the major transcriptional regulators of host gene expression. We previously reported that HIFs bind and activate hepatitis B virus (HBV) DNA transcription under low oxygen conditions; however, the global cellular response to low oxygen is mediated by a family of oxygenases that work in concert with HIFs. Recent studies have identified a role for chromatin modifiers in sensing cellular oxygen and orchestrating transcriptional responses, but their role in the HBV life cycle is as yet undefined. We demonstrated that histone lysine demethylase 4 (KDM4) can restrict HBV, and pharmacological or oxygen-mediated inhibition of the demethylase increases viral RNAs derived from both episomal and integrated copies of the viral genome. Sequencing studies demonstrated that KDM4 is a major regulator of the hepatic transcriptome, which defines hepatocellular permissivity to HBV infection. We propose a model where HBV exploits cellular oxygen sensors to replicate and persist in the liver. Understanding oxygen-dependent pathways that regulate HBV infection will facilitate the development of physiologically relevant cell-based models that support efficient HBV replication.


Hepatitis B virus , Jumonji Domain-Containing Histone Demethylases , Oxygen , Virus Replication , Humans , DNA, Viral/genetics , Genome, Viral/genetics , Hepatitis B/enzymology , Hepatitis B/metabolism , Hepatitis B/virology , Hepatitis B virus/genetics , Hepatitis B virus/growth & development , Hepatitis B virus/metabolism , Jumonji Domain-Containing Histone Demethylases/metabolism , Liver/enzymology , Liver/metabolism , Liver/virology , Oxygen/metabolism , Plasmids/genetics , Transcriptome , Virus Replication/genetics
4.
PLoS One ; 18(12): e0295184, 2023.
Article En | MEDLINE | ID: mdl-38117809

INTRODUCTION: We investigated the epidemiology of Cytochrome P450 (CYP) 3A4 genotype and the relationship between CYP3A4 genotype and alcohol drinking habits. MATERIALS AND METHODS: A single-centered retrospective study was conducted on 630 patients who underwent CYP3A4*1G genetic testing. Their relevant information on epidemiology and etiology was collected. Laboratory testing, including CYP3A4*1G genotype, liver function tests, and serum lipid measurements were performed. Bi-variate logistic regressions were used to examine the relationship between variables. The relationship between alcohol drinking and CYP3A4*1G genotype was estimated. Demographic and clinical features were analyzed. Participants with drinking history were divided into non-heavy drinking and heavy drinking groups. Liver function and dyslipidemia of participants with drinking histories were compared between CYP3A4*1G mutation (GA+AA) and wild-type (GG) groups. RESULTS: Participants with CYP3A4*1G mutation(GA+AA) had an increased adjusted odds ratio (AOR) of 2.56 (95% CI, 1.4-4.65; P = 0.00) for alcohol abuse when compared with participants without CYP3A4 mutation (GG). In the subgroup of participants with alcohol abuse, there are no significant differences in liver injury levels and serum lipid levels between CYP3A4*1G mutant and wild-type groups. Patients with CYP3A4*1G mutation had an increased AOR of cardiac-vascular diseases and malignant diseases compared with patients without CYP3A4*1G mutation. The epidemiology had no difference between GA and AA group. CONCLUSION: The study indicated that there was association between alcohol drinking and CYP3A4*1G genetic mutation. In the subgroup of participants with alcohol abuse, there are no significant differences in liver injury and dyslipidemia between CYP3A4*1G mutant and wild-type groups. CYP3A4*1G mutation was also related to cardiac-vascular diseases and malignant diseases.


Alcohol Drinking , Cytochrome P-450 CYP3A , Retrospective Studies , Humans , Alcohol Drinking/genetics , Cytochrome P-450 CYP3A/genetics , Genotype , Alcoholism/epidemiology , Alcoholism/genetics , China/epidemiology , Male , Adult , Middle Aged , Aged , Dyslipidemias/genetics , Liver/enzymology , Liver/injuries
5.
Analyst ; 148(23): 5991-6000, 2023 Nov 20.
Article En | MEDLINE | ID: mdl-37876282

High levels of D-amino acid oxidase (DAO) are associated with neurological and psychiatric disorders, while L-amino acid oxidase (LAO) exhibits antimicrobial and antitumor properties. The enzymatic conversion of the non-fluorescent kynurenine (KYN) into the endogenous weak fluorescent kynurenic acid (KYNA) by the action of DAO has previously been reported. However, the fluorescence of KYNA can be improved by changing the substituents on the aromatic rings. In this study, we prepared different 6-phenyl-substituted KYNA derivatives and investigated their fluorescence properties. Among them, 2-MePh-KYNA showed the maximum fluorescence quantum yield of 0.881 at 340 nm excitation and 418 nm emission wavelengths. The effects of solvent properties (dielectric constant, pKa, viscosity, and proticity) on the fluorescence intensity (FLI) of the KYNA derivatives were explored. The FLI of 2-MePh-KYNA was significantly large in protic solvents. Subsequently, 2-MePh-D-KYN and 2-MePh-L-KYN were prepared with high enantiopurity (>99.25%) for the enzymatic conversion. 2-MePh-D-KYN exhibited high sensitivity (∼19 times that of a commercial DAO substrate and ∼60 times that of the previously reported MeS-D-KYN) and high selectivity, as it was not cross-reactive towards LAO, while 2-MePh-L-KYN was also converted into 2-MePh-KYNA by LAO. Furthermore, the 2-MePh-D-KYN probe successfully detected DAO in eel liver, kidney, and heparin-anticoagulated plasma in the in vitro study.


D-Amino-Acid Oxidase , Kynurenic Acid , L-Amino Acid Oxidase , Kynurenic Acid/chemistry , Fluorescent Dyes , Eels , Animals , L-Amino Acid Oxidase/analysis , D-Amino-Acid Oxidase/analysis , Biological Assay , Fluorescence , Kinetics , Liver/enzymology , Kidney/enzymology
7.
Genes (Basel) ; 14(8)2023 07 28.
Article En | MEDLINE | ID: mdl-37628599

The application of nano drug delivery systems, particularly those utilizing natural bioactive compounds with anticancer properties, has gained significant attention. In this study, a novel nano-phytosome-loaded phenolic rich fraction (PRF) derived from Allium ampeloprasum L. was developed. The antitumor activity of the formulation was evaluated in BALB/c mice with TUBO colon carcinoma. The PRF-loaded nano-phytosome (PRF-NPs) exhibited a sphere-shaped structure (226 nm) and contained a diverse range of phenolic compounds. Animal trials conducted on TUBO tumor-bearing mice demonstrated that treatment with PRF-NPs at a dosage of 50 mg TPC/Kg/BW resulted in significant improvements in body weight and food intake, while reducing liver enzymes and lipid peroxidation. The expression of apoptosis-related genes, such as Bax and caspase-3, was upregulated, whereas Bcl2 was significantly downregulated (p < 0.05). Furthermore, the expression of GPx and SOD genes in the liver was notably increased compared to the control group. The findings suggest that the phytosomal encapsulation of the phenolic rich fraction derived from Allium ampeloprasum L. can enhance the bioavailability of natural phytochemicals and improve their antitumor properties. The development of PRF-NPs as a nano drug delivery system holds promise for effective breast cancer treatment.


Allium , Gene Expression Regulation , Allium/chemistry , Apoptosis/drug effects , Antioxidants/pharmacology , Phytosomes , Plant Extracts/pharmacology , Phenols/pharmacology , Nanostructures , Female , Animals , Mice , Mice, Inbred BALB C , Lipid Peroxidation , Liver/drug effects , Liver/enzymology , Body Weight , Antineoplastic Agents/pharmacology , Gene Expression Regulation/drug effects
8.
Prim Care ; 50(3): 363-376, 2023 Sep.
Article En | MEDLINE | ID: mdl-37516508

Abnormal liver tests are one of the most common challenges in the primary care setting. Primary care practitioners order these tests for numerous reasons, including investigating abdominal signs and symptoms or suspected alcohol-use disorder, or to determine medication adverse effects. Evaluation should be guided by both the clinical presentation and the pattern of injury. In this article, we will focus on the epidemiology, pathophysiology, clinical presentation, diagnostic work-up, and management of elevated liver enzymes, with an emphasis on the most common causes of abnormal liver testing.


Liver Diseases , Liver , Humans , Liver/enzymology , Liver Diseases/diagnosis
9.
Clin Chim Acta ; 544: 117335, 2023 Apr 01.
Article En | MEDLINE | ID: mdl-37037296

BACKGROUND: Muscle damage leads to increased serum creatine kinase (CK) levels in diseases such as acute myocardial infarction. Still, many individuals have abnormal serum CK activities lacking muscle-related diagnoses. The current study hypothesized that failed or overactivated CK clearance by non-muscle organs/tissues might be responsible for increased or decreased CK activities in blood. METHODS: We analyzing 37,081 independent CK test results in 36 human diseases during the past 5 y. RESULTS: We found that 33 out of 36 diseases were associated with decreased median CK activities compared to healthy controls. Besides muscle damage-related conditions, the highest mean CK activities were observed in hepatitis and cirrhosis. In contrast, 6 blood cell-related illnesses had the lowest mean CK values. ROC analysis showed that CK activities were the best biomarkers (AUC: 0.80-0.94) for the 6 blood-related diseases, especially myeloproliferative disorders. The principal component analysis revealed that the same category of diseases, such as liver-, blood -, kidney-, cancers, and vascular-related diseases, had clustered CK distributions. CONCLUSIONS: We proposed that the liver and blood cells were mainly responsible for CK clearance in blood circulation based on overall results. The testable mechanisms were presented and discussed.


Blood Cells , Creatine Kinase , Disease , Liver , Humans , Biomarkers , Blood Cells/enzymology , Creatine Kinase/metabolism , Creatine Kinase, MB Form , Isoenzymes/metabolism , Liver/enzymology , Retrospective Studies
10.
J Biol Chem ; 299(5): 104672, 2023 05.
Article En | MEDLINE | ID: mdl-37019215

It is a great honor to be invited to write a reflections article on my scientific journey and lifelong bile acid research for the Journal of Biological Chemistry, in which I am proud to have published 24 articles. I have also published 21 articles in the Journal of Lipid Research, another journal of the American Society of Biochemistry and Molecular Biology. I begin my reflections from my early education in Taiwan, my coming to America for graduate study, and continue with my postdoctoral training in cytochrome P450 research, and my lifelong bile acid research career at Northeast Ohio Medical University. I have witnessed and helped in the transformation of this rural not so visible medical school to a well-funded leader in liver research. Writing this reflections article on my long and rewarding journey in bile acid research brings back many good memories. I am proud of my scientific contributions and attribute my academic success to hard work, perseverance, good mentoring, and networking. I hope these reflections of my academic career would help inspire young investigators to pursue an academic career in biochemistry and metabolic diseases.


Bile Acids and Salts , Biochemistry , Biomedical Research , Liver , Humans , Bile Acids and Salts/metabolism , Biochemistry/history , Liver/enzymology , Liver/metabolism , Liver/pathology , Taiwan , Cytochrome P-450 Enzyme System , Ohio , Biomedical Research/history
11.
J Biol Chem ; 299(5): 104669, 2023 05.
Article En | MEDLINE | ID: mdl-37011860

Considerable evidence confirms the importance of Cyp26a1 to all-trans-retinoic acid (RA) homeostasis during embryogenesis. In contrast, despite its presence in postnatal liver as a potential major RA catabolizing enzyme and its acute sensitivity to induction by RA, some data suggested that Cyp26a1 contributes only marginally to endogenous RA homeostasis postnatally. We report reevaluation of a conditional Cyp26a1 knockdown in the postnatal mouse. The current results show that Cyp26a1 mRNA in WT mouse liver increases 16-fold upon refeeding after a fast, accompanied by an increased rate of RA elimination and a 41% decrease in the RA concentration. In contrast, Cyp26a1 mRNA in the refed homozygotic knockdown reached only 2% of its extent in WT during refeeding, accompanied by a slower rate of RA catabolism and no decrease in liver RA, relative to fasting. Refed homozygous knockdown mice also had decreased Akt1 and 2 phosphorylation and pyruvate dehydrogenase kinase 4 (Pdk4) mRNA and increased glucokinase (Gck) mRNA, glycogen phosphorylase (Pygl) phosphorylation, and serum glucose, relative to WT. Fasted homozygous knockdown mice had increased glucagon/insulin relative to WT. These data indicate that Cyp26a1 participates prominently in moderating the postnatal liver concentration of endogenous RA and contributes essentially to glucoregulatory control.


Blood Glucose , Homeostasis , Retinoic Acid 4-Hydroxylase , Tretinoin , Animals , Mice , Liver/enzymology , Liver/metabolism , Retinoic Acid 4-Hydroxylase/genetics , Retinoic Acid 4-Hydroxylase/metabolism , RNA, Messenger/genetics , Tretinoin/metabolism , Glucokinase/metabolism , Glycogen Phosphorylase/metabolism , Insulin/metabolism , Animals, Newborn , Phosphorylation , Blood Glucose/metabolism
12.
J Biochem Mol Toxicol ; 37(5): e23326, 2023 May.
Article En | MEDLINE | ID: mdl-36808657

Our experimental objective was to investigate the hepatotoxic effect of vincristine (VCR) administration in rats and determined whether combined therapy with Quercetin (Quer) ensured protection. Five groups with seven rats each were used for this purpose, and experimental groups were formulated as follows: Control group; Quer group; VCR group; VCR plus Quer 25 group; VCR plus Quer 50 group. The results showed that VCR significantly increased the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes. Besides, VCR caused considerable increases in the malondialdehyde (MDA) contents, along with significant decreases in reduced glutathione levels, superoxide dismutase, catalase, and glutathione peroxidase enzyme activities in the rat livers. Quer treatment in VCR toxicity markedly decreased the activity of ALT, AST, ALP enzymes, and MDA contents and enhanced the activities of antioxidant enzymes. The results also showed that VCR significantly increased the levels of NF-kB, STAT3, and the expression of caspase 3, Bax, and MAP LC3 and decreased the expression of Bcl2 and levels of Nrf2, HO-1, SIRT1, and PGC-1α. Compared to the VCR group, Quer treatment exhibited significantly lower levels of NF-kB, STAT3, and the expression of caspase 3, Bax, and MAP LC3, and higher levels of Nrf2, HO-1, SIRT1, and PGC-1α. In conclusion, our study demonstrated that Quer could alleviate the harmful effects of VCR via activation of NRf2/HO-1 and SIRT1/PGC-1α pathways, and via attenuation of oxidative stress, apoptosis, autophagy, and NF-kB/STAT3 pathways.


Antineoplastic Agents, Phytogenic , Chemical and Drug Induced Liver Injury , Quercetin , Vincristine , Animals , Rats , Vincristine/adverse effects , Male , Rats, Sprague-Dawley , Chemical and Drug Induced Liver Injury/blood , Chemical and Drug Induced Liver Injury/drug therapy , Chemical and Drug Induced Liver Injury/veterinary , Quercetin/administration & dosage , Liver/chemistry , Liver/enzymology , Liver/pathology , Caspase 3/metabolism , bcl-2-Associated X Protein/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Antineoplastic Agents, Phytogenic/adverse effects
13.
J Biol Chem ; 299(3): 102955, 2023 03.
Article En | MEDLINE | ID: mdl-36720308

Inorganic arsenic (iAs) is an environmental toxicant that can lead to severe health consequences, which can be exacerbated if exposure occurs early in development. Here, we evaluated the impact of oral iAs treatment on UDP-glucuronosyltransferase 1A1 (UGT1A1) expression and bilirubin metabolism in humanized UGT1 (hUGT1) mice. We found that oral administration of iAs to neonatal hUGT1 mice that display severe neonatal hyperbilirubinemia leads to induction of intestinal UGT1A1 and a reduction in total serum bilirubin values. Oral iAs administration accelerates neonatal intestinal maturation, an event that is directly associated with UGT1A1 induction. As a reactive oxygen species producer, oral iAs treatment activated the Keap-Nrf2 pathway in the intestinal tract and liver. When Nrf2-deficient hUGT1 mice (hUGT1/Nrf2-/-) were treated with iAs, it was shown that activated Nrf2 contributed significantly toward intestinal maturation and UGT1A1 induction. However, hepatic UGT1A1 was not induced upon iAs exposure. We previously demonstrated that the nuclear receptor PXR represses liver UGT1A1 in neonatal hUGT1 mice. When PXR was deleted in hUGT1 mice (hUGT1/Pxr-/-), derepression of UGT1A1 was evident in both liver and intestinal tissue in neonates. Furthermore, when neonatal hUGT1/Pxr-/- mice were treated with iAs, UGT1A1 was superinduced in both tissues, confirming PXR release derepressed key regulatory elements on the gene that could be activated by iAs exposure. With iAs capable of generating reactive oxygen species in both liver and intestinal tissue, we conclude that PXR deficiency in neonatal hUGT1/Pxr-/- mice allows greater access of activated transcriptional modifiers such as Nrf2 leading to superinduction of UGT1A1.


Arsenic , Glucuronosyltransferase , NF-E2-Related Factor 2 , Pregnane X Receptor , Animals , Mice , Animals, Newborn , Arsenic/toxicity , Bilirubin/blood , Glucuronosyltransferase/genetics , Glucuronosyltransferase/metabolism , Liver/enzymology , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Reactive Oxygen Species/metabolism , Pregnane X Receptor/genetics , Pregnane X Receptor/metabolism
14.
Steroids ; 191: 109163, 2023 03.
Article En | MEDLINE | ID: mdl-36581086

Curcumin is a phytochemical derived from the spice turmeric that is reported to have therapeutic effects. We are studying the enzyme steroid sulfatase (STS), which removes the sulfate group from inactive steroid hormones in peripheral tissues and we were interested in the effect of curcumin on STS activity due to its structural composition (polyphenolic). We sought to determine if curcumin affects STS activity in two model systems, rat liver and NIH-3T3 mouse fibroblast cells. STS assays were performed on tissue extracts of rat liver, and on NIH-3T3 microsomes and cells, with and without curcumin. Male and female rat liver extracts contained substantial amounts of STS activity, with males averaging higher (4-11 %) levels. Estradiol inhibited STS activity in livers of both sexes at 20 and 10 µM. Curcumin acted as a competitive inhibitor of STS activity in rat liver extracts, with a Ki of 19.8 µM in males and 9.3 µM in females. Curcumin also inhibited STS activity in NIH-3T3 microsomes at both 20 µM and 10 µM, and in whole NIH-3T3 cells at 20 µM. These data are the first to demonstrate STS inhibition by curcumin. Inhibition of STS results in lower active steroid hormone (estrogens and androgens) levels in tissues, possibly altering modulation of immune responses by these steroids.


Curcumin , Enzyme Inhibitors , Steryl-Sulfatase , Animals , Female , Male , Mice , Rats , Curcumin/pharmacology , Enzyme Inhibitors/pharmacology , Liver/drug effects , Liver/enzymology , Liver Extracts , NIH 3T3 Cells , Steryl-Sulfatase/antagonists & inhibitors
15.
J Cell Biochem ; 124(1): 103-117, 2023 Jan.
Article En | MEDLINE | ID: mdl-36377816

Tat-interactive protein 60 kDa (TIP60, also known as lysine acetyltransferase 5 [KAT5]) is a member of the MYST protein family with histone acetyltransferase activity. Recent studies have reported that TIP60 has multiple functions in many signal transduction mechanisms, especially p53-mediated apoptosis. Although the activation of apoptosis signaling pathways requires the presence of cellular reactive oxygen species (ROS) at a certain level, an imbalance between the production and consumption of ROS in cells results in oxidative stress (OS). In this study, we investigated for the first time how the absence of the Tip60 gene in the liver affects gene expression, enzyme activity, and protein expression of the hepatic antioxidant members localized in the cytoplasm, including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), and glutathione S-transferase (GST). First, we successfully generated liver-specific Tip60 knockout mice (mutants) using Cre/LoxP recombination. The reduced glutathione level and nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) expression, a marker of OS, increased significantly in the Tip60 mutant liver. Gene expression, activity, and protein expression of the enzymatic antioxidant system, including SOD, CAT, GR, GPx, and GST were investigated in mutants and control groups. Despite a significant correlation between the gene, enzyme activity, and protein content for CAT and GR, this was not true for SOD and GPx. The overall results suggest that TIP60 acts on the hepatic antioxidant system both at the gene and protein levels, but the actual effect of the deletion of Tip60 is observed at the protein level, especially for SOD and GPx.


Antioxidants , Liver , Lysine Acetyltransferase 5 , Oxidative Stress , Trans-Activators , Animals , Mice , Antioxidants/metabolism , Catalase/genetics , Catalase/metabolism , Glutathione/metabolism , Glutathione Peroxidase/genetics , Glutathione Peroxidase/metabolism , Glutathione Reductase/genetics , Lysine Acetyltransferase 5/genetics , Lysine Acetyltransferase 5/metabolism , Reactive Oxygen Species/metabolism , Superoxide Dismutase/metabolism , Trans-Activators/genetics , Trans-Activators/metabolism , Liver/enzymology
16.
Toxins (Basel) ; 14(12)2022 11 23.
Article En | MEDLINE | ID: mdl-36548717

Ricin toxin is an agent of biodefense concern and we have been developing countermeasures for ricin threats. In doing so, we sought biomarkers of ricin toxicosis and found that in mice parenteral injection of ricin toxin causes profound hypoglycemia, in the absence of other clinical laboratory abnormalities. We now seek to identify the mechanisms underlying this hypoglycemia. Within the first hours following injection, while still normoglycemic, lymphopenia and pro-inflammatory cytokine secretion were observed, particularly tumor necrosis factor (TNF)-α. The cytokine response evolved over the next day into a complex storm of both pro- and anti-inflammatory cytokines. Evaluation of pancreatic function and histology demonstrated marked islet hypertrophy involving predominantly ß-cells, but only mildly elevated levels of insulin secretion, and diminished hepatic insulin signaling. Drops in blood glucose were observed even after destruction of ß-cells with streptozotocin. In the liver, we observed a rapid and persistent decrease in the expression of glucose-6-phosphatase (G6Pase) RNA and protein levels, accompanied by a drop in glucose-6-phosphate and increase in glycogen. TNF-α has previously been reported to suppress G6Pase expression. In humans, a genetic deficiency of G6Pase results in glycogen storage disease, type-I (GSD-1), a hallmark of which is potentially fatal hypoglycemia.


Cytokines , Glucose-6-Phosphatase , Hypoglycemia , Liver , Ricin , Animals , Humans , Mice , Cytokines/metabolism , Glucose-6-Phosphatase/genetics , Glucose-6-Phosphatase/metabolism , Hypoglycemia/chemically induced , Hypoglycemia/metabolism , Liver/drug effects , Liver/enzymology , Liver/metabolism , Ricin/toxicity , Ricin/metabolism
17.
Science ; 377(6613): 1399-1406, 2022 09 23.
Article En | MEDLINE | ID: mdl-36137043

Tissue-tissue communication by endocrine factors is a vital mechanism for physiologic homeostasis. A systems genetics analysis of transcriptomic and functional data from a cohort of diverse, inbred strains of mice predicted that coagulation factor XI (FXI), a liver-derived protein, protects against diastolic dysfunction, a key trait of heart failure with preserved ejection fraction. This was confirmed using gain- and loss-of-function studies, and FXI was found to activate the bone morphogenetic protein (BMP)-SMAD1/5 pathway in the heart. The proteolytic activity of FXI is required for the cleavage and activation of extracellular matrix-associated BMP7 in the heart, thus inhibiting genes involved in inflammation and fibrosis. Our results reveal a protective role of FXI in heart injury that is distinct from its role in coagulation.


Bone Morphogenetic Protein 7 , Factor XI , Heart Failure , Liver , Myocardium , Animals , Bone Morphogenetic Protein 7/metabolism , Factor XI/genetics , Factor XI/metabolism , Fibrosis , Heart Failure/genetics , Heart Failure/metabolism , Humans , Inflammation/genetics , Liver/enzymology , Male , Mice , Mice, Inbred C57BL , Myocardium/metabolism , Myocardium/pathology , Proteolysis
18.
Int J Mol Sci ; 23(16)2022 Aug 18.
Article En | MEDLINE | ID: mdl-36012560

Choline deficiency causes hepatic fat accumulation, and is associated with a higher risk of nonalcoholic fatty liver disease (NAFLD) and more advanced NAFLD-related hepatic fibrosis. Reduced expression of hepatic phosphatidylethanolamine N-methyltransferase (PEMT), which catalyzes the production of phosphatidylcholine, causes steatosis, inflammation, and fibrosis in mice. In humans, common PEMT variants impair phosphatidylcholine synthesis, and are associated with NAFLD risk. We investigated hepatic PEMT expression in a large cohort of patients representing the spectrum of NAFLD, and examined the relationship between PEMT genetic variants and gene expression. Hepatic PEMT expression was reduced in NAFLD patients with inflammation and fibrosis (i.e., nonalcoholic steatohepatitis or NASH) compared to participants with normal liver histology (ß = −1.497; p = 0.005). PEMT levels also declined with increasing severity of fibrosis with cirrhosis < incomplete cirrhosis < bridging fibrosis (ß = −1.185; p = 0.011). Hepatic PEMT expression was reduced in postmenopausal women with NASH compared to those with normal liver histology (ß = −3.698; p = 0.030). We detected a suggestive association between rs7946 and hepatic fibrosis (p = 0.083). Although none of the tested variants were associated with hepatic PEMT expression, computational fine mapping analysis indicated that rs4646385 may impact PEMT levels in the liver. Hepatic PEMT expression decreases with increasing severity of NAFLD in obese individuals and postmenopausal women, and may contribute to disease pathogenesis in a subset of NASH patients.


Non-alcoholic Fatty Liver Disease , Phosphatidylethanolamine N-Methyltransferase , Female , Fibrosis , Humans , Inflammation/pathology , Liver/enzymology , Liver Cirrhosis/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , Phosphatidylcholines/metabolism , Phosphatidylethanolamine N-Methyltransferase/genetics , Phosphatidylethanolamine N-Methyltransferase/metabolism
19.
J Alzheimers Dis ; 88(4): 1371-1376, 2022.
Article En | MEDLINE | ID: mdl-35786657

To investigate an association of serum liver enzymes with Alzheimer's disease (AD) diagnosis and cognitive performance, we performed logistic and linear regression analyses in 781 patients with AD and 405 cognitively normal subjects. We found that alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels had significant positive associations with cognitive performance and were significantly decreased in AD patients. The alkaline phosphatase level and AST to ALT ratio were significantly negatively associated with cognitive performance and were significantly increased in AD patients. This suggests that these liver enzymes might be implicated in the pathogenesis of AD.


Alzheimer Disease , Cognition , Liver , Alanine Transaminase , Alzheimer Disease/physiopathology , Aspartate Aminotransferases , Humans , Liver/enzymology
20.
N Engl J Med ; 387(6): 514-524, 2022 08 11.
Article En | MEDLINE | ID: mdl-35748699

BACKGROUND: Alpha1-antitrypsin (AAT) deficiency results from carriage of a homozygous SERPINA1 "Z" mutation (proteinase inhibitor [PI] ZZ). The Z allele produces a mutant AAT protein called Z-AAT, which accumulates in hepatocytes and can lead to progressive liver disease and fibrosis. This open-label, phase 2 trial investigated the safety and efficacy of fazirsiran, an RNA interference therapeutic, in patients with liver disease associated with AAT deficiency. METHODS: We assigned adults with the PI ZZ genotype and liver fibrosis to receive fazirsiran at a dose of 200 mg (cohorts 1 [4 patients] and 2 [8 patients]) or 100 mg (cohort 1b [4 patients]) subcutaneously on day 1 and week 4 and then every 12 weeks. The primary end point was the change from baseline to week 24 (cohorts 1 and 1b) or week 48 (cohort 2) in liver Z-AAT concentrations, which were measured by means of liquid chromatography-mass spectrometry. RESULTS: All the patients had reduced accumulation of Z-AAT in the liver (median reduction, 83% at week 24 or 48). The nadir in serum was a reduction of approximately 90%, and treatment was also associated with a reduction in histologic globule burden (from a mean score of 7.4 [scores range from 0 to 9, with higher scores indicating a greater globule burden] at baseline to 2.3 at week 24 or 48). All cohorts had reductions in liver enzyme concentrations. Fibrosis regression was observed in 7 of 15 patients and fibrosis progression in 2 of 15 patients after 24 or 48 weeks. There were no adverse events leading to trial or drug discontinuation. Four serious adverse events (viral myocarditis, diverticulitis, dyspnea, and vestibular neuronitis) resolved. CONCLUSIONS: In this small trial, fazirsiran was associated with a strong reduction of Z-AAT concentrations in the serum and liver and concurrent improvements in liver enzyme concentrations. (Funded by Arrowhead Pharmaceuticals; AROAAT-2002 ClinicalTrials.gov number, NCT03946449.).


Liver Cirrhosis , RNAi Therapeutics , alpha 1-Antitrypsin Deficiency , alpha 1-Antitrypsin , Adult , Genotype , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Injections, Subcutaneous , Liver/drug effects , Liver/enzymology , Liver/metabolism , Liver Cirrhosis/drug therapy , Liver Cirrhosis/etiology , Liver Cirrhosis/genetics , Mutation , RNAi Therapeutics/adverse effects , RNAi Therapeutics/methods , alpha 1-Antitrypsin/analysis , alpha 1-Antitrypsin/blood , alpha 1-Antitrypsin/genetics , alpha 1-Antitrypsin Deficiency/complications , alpha 1-Antitrypsin Deficiency/drug therapy , alpha 1-Antitrypsin Deficiency/genetics
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