RESUMO
Genetic changes causing brain size expansion in human evolution have remained elusive. Notch signaling is essential for radial glia stem cell proliferation and is a determinant of neuronal number in the mammalian cortex. We find that three paralogs of human-specific NOTCH2NL are highly expressed in radial glia. Functional analysis reveals that different alleles of NOTCH2NL have varying potencies to enhance Notch signaling by interacting directly with NOTCH receptors. Consistent with a role in Notch signaling, NOTCH2NL ectopic expression delays differentiation of neuronal progenitors, while deletion accelerates differentiation into cortical neurons. Furthermore, NOTCH2NL genes provide the breakpoints in 1q21.1 distal deletion/duplication syndrome, where duplications are associated with macrocephaly and autism and deletions with microcephaly and schizophrenia. Thus, the emergence of human-specific NOTCH2NL genes may have contributed to the rapid evolution of the larger human neocortex, accompanied by loss of genomic stability at the 1q21.1 locus and resulting recurrent neurodevelopmental disorders.
Assuntos
Encéfalo/embriologia , Córtex Cerebral/fisiologia , Neurogênese/fisiologia , Receptor Notch2/metabolismo , Transdução de Sinais , Animais , Diferenciação Celular , Células-Tronco Embrionárias/metabolismo , Feminino , Deleção de Genes , Genes Reporter , Gorilla gorilla , Células HEK293 , Humanos , Neocórtex/citologia , Células-Tronco Neurais/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Pan troglodytes , Receptor Notch2/genética , Análise de Sequência de RNARESUMO
X-linked dystonia-parkinsonism (XDP) is a severe neurodegenerative disorder resulting from an inherited intronic SINE-Alu-VNTR (SVA) retrotransposon in the TAF1 gene that causes dysregulation of TAF1 transcription. The specific mechanism underlying this dysregulation remains unclear, but it is hypothesized to involve the formation of G-quadruplexes (G4) structures within the XDP-SVA that impede transcription. In this study, we show that ZNF91, a critical repressor of SVA retrotransposons, specifically binds to G4-forming DNA sequences. Further, we found that genetic deletion of ZNF91 exacerbates the molecular phenotype associated with the XDP-SVA insertion in patient cells, while no difference was observed when ZNF91 was deleted from isogenic control cells. Additionally, we observed a significant age-related reduction in ZNF91 expression in whole blood and brain, indicating a progressive loss of repression of the XDP-SVA in XDP. These findings indicate that ZNF91 plays a crucial role in controlling the molecular phenotype associated with XDP. Since ZNF91 binds to G4-forming DNA sequences in SVAs, this suggests that interactions between ZNF91 and G4-forming sequences in the XDP-SVA minimize the severity of the molecular phenotype. Our results showing that ZNF91 expression levels significantly decrease with age provide a potential explanation for the age-related progressive neurodegenerative character of XDP. Collectively, our study provides important insights into the protective role of ZNF91 in XDP pathogenesis and suggests that restoring ZNF91 expression, destabilization of G4s, or targeted repression of the XDP-SVA could be future therapeutic strategies to prevent or treat XDP.
Assuntos
Distúrbios Distônicos , Doenças Genéticas Ligadas ao Cromossomo X , Fenótipo , Humanos , Distúrbios Distônicos/genética , Distúrbios Distônicos/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Quadruplex G , Fatores Associados à Proteína de Ligação a TATA/genética , Fatores Associados à Proteína de Ligação a TATA/metabolismo , Masculino , Fator de Transcrição TFIID/genética , Fator de Transcrição TFIID/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Retroelementos/genética , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismoRESUMO
The interaction between menin and histone-lysine N-methyltransferase 2A (KMT2A) is a critical dependency for KMT2A- or nucleophosmin 1 (NPM1)-altered leukemias and an emerging opportunity for therapeutic development. JNJ-75276617 is a novel, orally bioavailable, potent, and selective protein-protein interaction inhibitor of the binding between menin and KMT2A. In KMT2A-rearranged (KMT2A-r) and NPM1-mutant (NPM1c) AML cells, JNJ-75276617 inhibited the association of the menin-KMT2A complex with chromatin at target gene promoters, resulting in reduced expression of several menin-KMT2A target genes, including MEIS1 and FLT3. JNJ-75276617 displayed potent anti-proliferative activity across several AML and ALL cell lines and patient samples harboring KMT2A- or NPM1-alterations in vitro. In xenograft models of AML and ALL, JNJ-75276617 reduced leukemic burden and provided a significant dose-dependent survival benefit accompanied by expression changes of menin-KMT2A target genes. JNJ-75276617 demonstrated synergistic effects with gilteritinib in vitro in AML cells harboring KMT2A-r. JNJ-75276617 further exhibited synergistic effects with venetoclax and azacitidine in AML cells bearing KMT2A-r in vitro, and significantly increased survival in mice. Interestingly, JNJ-75276617 showed potent anti-proliferative activity in cell lines engineered with recently discovered mutations (MEN1M327I or MEN1T349M) that developed in patients refractory to the menin-KMT2A inhibitor revumenib. A co-crystal structure of menin in complex with JNJ-75276617 indicates a unique binding mode distinct from other menin-KMT2A inhibitors, including revumenib. JNJ-75276617 is being clinically investigated for acute leukemias harboring KMT2A or NPM1 alterations, as a monotherapy for relapsed/refractory (R/R) acute leukemia (NCT04811560), or in combination with AML-directed therapies (NCT05453903).
RESUMO
Genome-wide association studies (GWAS) have been highly informative in discovering disease-associated loci but are not designed to capture all structural variations in the human genome. Using long-read sequencing data, we discovered widespread structural variation within SINE-VNTR-Alu (SVA) elements, a class of great ape-specific transposable elements with gene-regulatory roles, which represents a major source of structural variability in the human population. We highlight the presence of structurally variable SVAs (SV-SVAs) in neurological disease-associated loci, and we further associate SV-SVAs to disease-associated SNPs and differential gene expression using luciferase assays and expression quantitative trait loci data. Finally, we genetically deleted SV-SVAs in the BIN1 and CD2AP Alzheimer's disease-associated risk loci and in the BCKDK Parkinson's disease-associated risk locus and assessed multiple aspects of their gene-regulatory influence in a human neuronal context. Together, this study reveals a novel layer of genetic variation in transposable elements that may contribute to identification of the structural variants that are the actual drivers of disease associations of GWAS loci.
Assuntos
Elementos de DNA Transponíveis , Estudo de Associação Genômica Ampla , Elementos Alu , Elementos de DNA Transponíveis/genética , Predisposição Genética para Doença , Variação Genética , Genoma Humano , Humanos , Polimorfismo de Nucleotídeo Único , Locos de Características QuantitativasRESUMO
Transposable element (TE) invasions have shaped vertebrate genomes over the course of evolution. They have contributed an extra layer of species-specific gene regulation by providing novel transcription factor binding sites. In humans, SINE-VNTR-Alu (SVA) elements are one of three still active TE families; approximately 2800 SVA insertions exist in the human genome, half of which are human-specific. TEs are often silenced by KRAB zinc finger (KZNF) proteins recruiting corepressor proteins that establish a repressive chromatin state. A number of KZNFs have been reported to bind SVAs, but their individual contribution to repressing SVAs and their roles in suppressing SVA-mediated gene-regulatory effects remains elusive. We analyzed the genome-wide binding profile for ZNF91 in human cells and found that ZNF91 interacts with the VNTR region of SVAs. Through CRISPR-Cas9-mediated deletion of ZNF91 in human embryonic stem cells, we established that loss of ZNF91 results in increased transcriptional activity of SVAs. In contrast, SVA activation was not observed upon genetic deletion of the ZNF611 gene encoding another strong SVA interactor. Epigenetic profiling confirmed the loss of SVA repression in the absence of ZNF91 and revealed that mainly evolutionary young SVAs gain gene activation-associated epigenetic modifications. Genes close to activated SVAs showed a mild up-regulation, indicating SVAs adopt properties of cis-regulatory elements in the absence of repression. Notably, genome-wide derepression of SVAs elicited the communal up-regulation of KZNFs that reside in KZNF clusters. This phenomenon may provide new insights into the potential mechanisms used by the host genome to sense and counteract TE invasions.
Assuntos
Células-Tronco Embrionárias Humanas , Fatores de Transcrição Kruppel-Like/deficiência , Família Multigênica/genética , Proteínas Repressoras/genética , Retroelementos/genética , Ativação Transcricional , Regulação para Cima , Genoma Humano , Humanos , Dedos de Zinco/genéticaRESUMO
Madin-Darby canine kidney (MDCK) cells are widely used to study epithelial cell functionality. Their low endogenous drug transporter protein levels make them an amenable system to investigate transepithelial permeation and drug transporter protein activity after their transfection. MDCK cells display diverse phenotypic traits, and as such, laboratory-to-laboratory variability in drug permeability assessments is observed. Consequently, in vitro-in vivo extrapolation (IVIVE) approaches using permeability and/or transporter activity data require calibration. A comprehensive proteomic quantification of 11 filter-grown parental or mock-transfected MDCK monolayers from 8 different pharmaceutical laboratories using the total protein approach (TPA) is provided. The TPA enables estimations of key morphometric parameters such as monolayer cellularity and volume. Overall, metabolic liability to xenobiotics is likely to be limited for MDCK cells due to the low expression of required enzymes. SLC16A1 (MCT1) was the highest abundant SLC transporter linked to xenobiotic activity, while ABCC4 (MRP4) was the highest abundant ABC transporter. Our data supports existing findings that claudin-2 levels may be linked to tight junction modulation, thus impacting trans-epithelial resistance. This unique database provides data on more than 8000 protein copy numbers and concentrations, thus allowing an in-depth appraisal of the control monolayers used in each laboratory.
Assuntos
Proteoma , Proteômica , Animais , Cães , Células Madin Darby de Rim Canino , Proteoma/metabolismo , Junções Íntimas/metabolismo , Rim/metabolismo , Proteínas de Transporte/metabolismoRESUMO
Ever since the availability of genomes from Neanderthals, Denisovans, and ancient humans, the field of evolutionary genomics has been searching for protein-coding variants that may hold clues to how our species evolved over the last â¼600,000 years. In this study, we identify such variants in the human-specific NOTCH2NL gene family, which were recently identified as possible contributors to the evolutionary expansion of the human brain. We find evidence for the existence of unique protein-coding NOTCH2NL variants in Neanderthals and Denisovans which could affect their ability to activate Notch signaling. Furthermore, in the Neanderthal and Denisovan genomes, we find unusual NOTCH2NL configurations, not found in any of the modern human genomes analyzed. Finally, genetic analysis of archaic and modern humans reveals ongoing adaptive evolution of modern human NOTCH2NL genes, identifying three structural variants acting complementary to drive our genome to produce a lower dosage of NOTCH2NL protein. Because copy-number variations of the 1q21.1 locus, encompassing NOTCH2NL genes, are associated with severe neurological disorders, this seemingly contradicting drive toward low levels of NOTCH2NL protein indicates that the optimal dosage of NOTCH2NL may have not yet been settled in the human population.
Assuntos
Evolução Biológica , Homem de Neandertal/genética , Receptor Notch2/genética , Animais , Genoma Humano , Variação Estrutural do Genoma , Humanos , Família Multigênica , Receptor Notch2/metabolismoRESUMO
Throughout evolution primate genomes have been modified by waves of retrotransposon insertions. For each wave, the host eventually finds a way to repress retrotransposon transcription and prevent further insertions. In mouse embryonic stem cells, transcriptional silencing of retrotransposons requires KAP1 (also known as TRIM28) and its repressive complex, which can be recruited to target sites by KRAB zinc-finger (KZNF) proteins such as murine-specific ZFP809 which binds to integrated murine leukaemia virus DNA elements and recruits KAP1 to repress them. KZNF genes are one of the fastest growing gene families in primates and this expansion is hypothesized to enable primates to respond to newly emerged retrotransposons. However, the identity of KZNF genes battling retrotransposons currently active in the human genome, such as SINE-VNTR-Alu (SVA) and long interspersed nuclear element 1 (L1), is unknown. Here we show that two primate-specific KZNF genes rapidly evolved to repress these two distinct retrotransposon families shortly after they began to spread in our ancestral genome. ZNF91 underwent a series of structural changes 8-12 million years ago that enabled it to repress SVA elements. ZNF93 evolved earlier to repress the primate L1 lineage until â¼12.5 million years ago when the L1PA3-subfamily of retrotransposons escaped ZNF93's restriction through the removal of the ZNF93-binding site. Our data support a model where KZNF gene expansion limits the activity of newly emerged retrotransposon classes, and this is followed by mutations in these retrotransposons to evade repression, a cycle of events that could explain the rapid expansion of lineage-specific KZNF genes.
Assuntos
Evolução Molecular , Fatores de Transcrição Kruppel-Like/metabolismo , Primatas/genética , Retroelementos/genética , Animais , Sequência de Bases , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Humanos , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Mutação/genética , Dedos de ZincoRESUMO
In this phase 1 study, the absolute bioavailability and absorption, metabolism, and excretion (AME) of apalutamide, a competitive inhibitor of the androgen receptor, were evaluated in 12 healthy men. Subjects received 240 mg of apalutamide orally plus a 15-minute intravenous infusion of 100 µg of apalutamide containing 9.25 kBq (250 nCi) of 14C-apalutamide (2 hours postdose) for absolute bioavailability assessment or plus one 400-µg capsule containing 37 kBq (1000 nCi) of 14C-apalutamide for AME assessment. Content of 14C and metabolite profiling for whole blood, plasma, urine, feces, and expired air samples were analyzed using accelerator mass spectrometry. Apalutamide absolute oral bioavailability was ≈100%. After oral administration, apalutamide, its N-desmethyl metabolite (M3), and an inactive carboxylic acid metabolite (M4) accounted for most 14C in plasma (45%, 44%, and 3%, respectively). Apalutamide elimination was slow, with a mean plasma half-life of 151-178 hours. The mean cumulative recovery of total 14C over 70 days postdose was 64.6% in urine and 24.3% in feces. The urinary excretion of apalutamide, M3, and M4 was 1.2%, 2.7%, and 31.1% of dose, respectively. Fecal excretion of apalutamide, M3, and M4 was 1.5%, 2.0%, and 2.4% of dose, respectively. Seventeen apalutamide metabolites and six main metabolic clearance pathways were identified. In vitro studies confirmed CYP2C8 and CYP3A4 roles in apalutamide metabolism.
Assuntos
Hepatócitos/metabolismo , Tioidantoínas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Disponibilidade Biológica , Líquidos Corporais/metabolismo , Radioisótopos de Carbono/metabolismo , Citocromo P-450 CYP2C8/metabolismo , Citocromo P-450 CYP3A/metabolismo , Fezes/química , Meia-Vida , Humanos , Infusões Intravenosas/métodos , Masculino , Taxa de Depuração Metabólica/fisiologia , Pessoa de Meia-IdadeRESUMO
A causal role of hypercholesterolemia in non-ischemic heart failure has never been demonstrated. Adeno-associated viral serotype 8 (AAV8)-low-density lipoprotein receptor (AAV8-LDLr) gene transfer was performed in LDLr-deficient mice without and with pressure overload induced by transverse aortic constriction (TAC). AAV8-LDLr gene therapy resulted in an 82.8% (p < 0.0001) reduction of plasma cholesterol compared with controls. Mortality rate was lower (p < 0.05) in AAV8-LDLr TAC mice compared with control TAC mice (hazard ratio for mortality 0.457, 95% confidence interval [CI] 0.237-0.882) during 8 weeks of follow-up. AAV8-LDLr gene therapy attenuated cardiac hypertrophy, reduced interstitial and perivascular fibrosis, and decreased lung congestion in TAC mice. Cardiac function, quantified by invasive hemodynamic measurements and magnetic resonance imaging, was significantly improved 8 weeks after sham operation or after TAC in AAV8-LDLr mice compared with respective control groups. Myocardial protein levels of mammalian target of rapamycin and of acetyl-coenzyme A carboxylase were strikingly decreased following cholesterol lowering in mice without and with pressure overload. AAV8-LDLr therapy potently reduced cardiac glucose uptake and counteracted metabolic remodeling following pressure overload. Furthermore, oxidative stress and myocardial apoptosis were decreased following AAV8-LDLr therapy in mice with pressure overload. In conclusion, cholesterol-lowering gene therapy potently counteracts structural and metabolic remodeling, and enhances cardiac function.
Assuntos
Cardiomegalia/terapia , Cardiomiopatias/terapia , Colesterol/metabolismo , Terapia Genética/métodos , Vetores Genéticos/metabolismo , Receptores de LDL/genética , Acetil-CoA C-Acetiltransferase/genética , Acetil-CoA C-Acetiltransferase/metabolismo , Animais , Aorta/cirurgia , Biomarcadores/metabolismo , Cardiomegalia/etiologia , Cardiomegalia/metabolismo , Cardiomegalia/mortalidade , Cardiomiopatias/etiologia , Cardiomiopatias/metabolismo , Cardiomiopatias/mortalidade , Constrição Patológica/complicações , Constrição Patológica/metabolismo , Constrição Patológica/patologia , Dependovirus/genética , Dependovirus/metabolismo , Feminino , Expressão Gênica , Vetores Genéticos/administração & dosagem , Vetores Genéticos/química , Testes de Função Cardíaca , Hemodinâmica , Camundongos , Camundongos Knockout , Miocárdio/metabolismo , Miocárdio/patologia , Receptores de LDL/deficiência , Análise de Sobrevida , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismoRESUMO
PURPOSE: In view of pediatric drug development, juvenile animal studies are gaining importance. However, data on drug metabolizing capacities of juvenile animals are scarce, especially in non-rodent species. Therefore, we aimed to characterize the in vitro biotransformation of four human CYP450 substrates and one UGT substrate in the livers of developing Göttingen minipigs. METHODS: Liver microsomes from late fetal, Day 1, Day 3, Day 7, Day 28, and adult male and female Göttingen minipigs were incubated with a cocktail of CYP450 substrates, including phenacetin, tolbutamide, dextromethorphan, and midazolam. The latter are probe substrates for human CYP1A2, CYP2C9, CYP2D6, and CYP3A4, respectively. In addition, the UGT multienzyme substrate (from the UGT-GloTM assay), which is glucuronidated by several human UGT1A and UGT2B enzymes, was also incubated with the porcine liver microsomes. RESULTS: For all tested substrates, drug metabolism significantly rose postnatally. At one month of age, 60.5 and 75.4% of adult activities were observed for acetaminophen and dextrorphan formations, respectively, while 35.4 and 43.2% of adult activities were present for 4-OH-tolbutamide and 1'-OH-midazolam formations. Biotransformation of phenacetin was significantly higher in 28-day-old and adult females compared with males. CONCLUSIONS: Maturation of metabolizing capacities occurred postnatally, as described in man.
Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Microssomos Hepáticos/metabolismo , Fatores Etários , Animais , Animais Recém-Nascidos , Biotransformação , Dextrometorfano/metabolismo , Feminino , Feto , Glucuronosiltransferase/metabolismo , Humanos , Masculino , Desintoxicação Metabólica Fase I , Desintoxicação Metabólica Fase II , Midazolam/metabolismo , Fenacetina/metabolismo , Suínos , Porco Miniatura , Tolbutamida/metabolismoRESUMO
Epidemiological studies support an independent inverse association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. The effect of selective HDL-raising adeno-associated viral serotype 8-human apolipoprotein (apo) A-I (AAV8-A-I) gene transfer on cardiac remodeling induced by transverse aortic constriction (TAC) was evaluated in C57BL/6 low-density lipoprotein receptor-deficient mice. Septal wall thickness and cardiomyocyte cross-sectional area were reduced by 16.5% (p < 0.001) and by 13.8% (p < 0.01), respectively, eight weeks after TAC in AAV8-A-I mice (n = 24) compared to control mice (n = 39). Myocardial capillary density was 1.11-fold (p < 0.05) higher and interstitial cardiac fibrosis was 45.3% (p < 0.001) lower in AAV8-A-I TAC mice than in control TAC mice. Lung weight and atrial weight were significantly increased in control TAC mice compared to control sham mice, but were not increased in AAV8-A-I TAC mice. The peak rate of isovolumetric contraction was 1.19-fold (p < 0.01) higher in AAV8-A-I TAC mice (n = 17) than in control TAC mice (n = 29). Diastolic function was also significantly enhanced in AAV8-A-I TAC mice compared to control TAC mice. Nitro-oxidative stress and apoptosis were significantly reduced in the myocardium of AAV8-A-I TAC mice compared to control TAC mice. In conclusion, selective HDL-raising human apo A-I gene transfer potently counteracts the development of pressure overload-induced cardiomyopathy.
Assuntos
Apolipoproteína A-I/metabolismo , Cardiomegalia/terapia , Cardiomiopatias/terapia , Terapia Genética/métodos , Lipoproteínas HDL/metabolismo , Animais , Apolipoproteína A-I/genética , Cardiomegalia/genética , Cardiomegalia/metabolismo , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Fibrose/genética , Fibrose/terapia , Coração/fisiopatologia , Humanos , Estimativa de Kaplan-Meier , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miocárdio/metabolismo , Miocárdio/patologiaRESUMO
The derivation of hepatocytes from human induced pluripotent stem cells (hiPSC) is of great interest for applications in pharmacological research. However, full maturation of hiPSC-derived hepatocytes has not yet been achieved in vitro. To improve hepatic differentiation, co-cultivation of hiPSC with human umbilical vein endothelial cells (HUVEC) during hepatic differentiation was investigated in this study. In the first step, different culture media variations based on hepatocyte culture medium (HCM) were tested in HUVEC mono-cultures to establish a suitable culture medium for co-culture experiments. Based on the results, two media variants were selected to differentiate hiPSC-derived definitive endodermal (DE) cells into mature hepatocytes with or without HUVEC addition. DE cells differentiated in mono-cultures in the presence of those media variants showed a significant increase (p < 0.05) in secretion of α-fetoprotein and in activities of cytochrome P450 (CYP) isoenzymes CYP2B6 and CYP3A4 as compared with cells differentiated in unmodified HCM used as control. Co-cultivation with HUVEC did not further improve the differentiation outcome. Thus, it can be concluded that the effect of the used medium outweighed the effect of HUVEC co-culture, emphasizing the importance of the culture medium composition for hiPSC differentiation.
Assuntos
Diferenciação Celular , Meios de Cultivo Condicionados/farmacologia , Hepatócitos/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Albuminas/metabolismo , Biomarcadores , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Técnicas de Cocultura , Meios de Cultura , Sistema Enzimático do Citocromo P-450 , Células Endoteliais/metabolismo , Expressão Gênica , Perfilação da Expressão Gênica , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Células Endoteliais da Veia Umbilical Humana/citologia , Humanos , Imuno-Histoquímica , Ureia/metabolismo , alfa-Fetoproteínas/metabolismoRESUMO
Studies evaluating the effects of high-saturated fat diets on cardiac function are most often confounded by diet-induced obesity and by systemic insulin resistance. We evaluated whether coconut oil, containing C12:0 and C14:0 as main fatty acids, aggravates pressure overload-induced cardiomyopathy induced by transverse aortic constriction (TAC) in C57BL/6 mice. Mortality rate after TAC was higher (p < 0.05) in 0.2% cholesterol 10% coconut oil diet-fed mice than in standard chow-fed mice (hazard ratio 2.32, 95% confidence interval 1.16 to 4.64) during eight weeks of follow-up. The effects of coconut oil on cardiac remodeling occurred in the absence of weight gain and of systemic insulin resistance. Wet lung weight was 1.76-fold (p < 0.01) higher in coconut oil mice than in standard chow mice. Myocardial capillary density (p < 0.001) was decreased, interstitial fibrosis was 1.88-fold (p < 0.001) higher, and systolic and diastolic function was worse in coconut oil mice than in standard chow mice. Myocardial glucose uptake was 1.86-fold (p < 0.001) higher in coconut oil mice and was accompanied by higher myocardial pyruvate dehydrogenase levels and higher acetyl-CoA carboxylase levels. The coconut oil diet increased oxidative stress. Myocardial triglycerides and free fatty acids were lower (p < 0.05) in coconut oil mice. In conclusion, coconut oil aggravates pressure overload-induced cardiomyopathy.
Assuntos
Cardiomiopatias/patologia , Óleo de Coco/efeitos adversos , Resistência à Insulina , Miocárdio/patologia , Obesidade/patologia , Pressão , Animais , Aorta/patologia , Peso Corporal , Capilares/patologia , Cardiomiopatias/sangue , Cardiomiopatias/complicações , Cardiomiopatias/fisiopatologia , Colesterol , Constrição Patológica , Diástole , Dieta , Feminino , Fibrose , Glucose/metabolismo , Hemodinâmica , Hipertrofia Ventricular Direita/complicações , Hipertrofia Ventricular Direita/patologia , Hipertrofia Ventricular Direita/fisiopatologia , Estimativa de Kaplan-Meier , Pulmão/patologia , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Transdução de Sinais , Sístole , Fator de Crescimento Transformador beta1/metabolismoRESUMO
RATIONALE: Familial hypercholesterolemia is a genetic disorder that arises because of loss-of-function mutations in the low-density lipoprotein receptor (LDLR) and homozygous familial hypercholesterolemia is a candidate for gene therapy using adeno-associated viral vectors. Proprotein convertase subtilisin/kexin type 9 (PCSK9) and inducible degrader of LDLR (IDOL) negatively regulate LDLR protein and could dampen adeno-associated viral vector encoded LDLR expression. OBJECTIVE: We sought to create vectors expressing gain-of-function human LDLR variants that are resistant to degradation by human PCSK9 (hPCSK9) and IDOL and thereby enhance hepatic LDLR protein abundance and plasma LDL cholesterol reduction. METHODS AND RESULTS: Amino acid substitutions were introduced into the coding sequence of human LDLR cDNA to reduce interaction with hPCSK9 and human IDOL. A panel of mutant human LDLRs was initially screened in vitro for escape from PCSK9. The variant human LDLR-L318D was further evaluated using a mouse model of homozygous familial hypercholesterolemia lacking endogenous LDLR and apolipoprotein B mRNA editing enzyme catalytic, APOBEC-1 (double knockout). Administration of wild-type human LDLR to double knockout mice, expressing hPCSK9, led to diminished LDLR activity. However, LDLR-L318D was resistant to hPCSK9-mediated degradation and effectively reduced cholesterol levels. Similarly, the LDLR-K809R\C818A construct avoided human IDOL regulation and achieved stable reductions in serum cholesterol. An adeno-associated viral vector serotype 8.LDLR-L318D\K809R\C818A vector that carried all 3 amino acid substitutions conferred partial resistance to both hPCSK9- and human IDOL-mediated degradation. CONCLUSIONS: Amino acid substitutions in the human LDLR confer partial resistance to PCSK9 and IDOL regulatory pathways with improved reduction in cholesterol levels and improve on a potential gene therapeutic approach to treat homozygous familial hypercholesterolemia subjects.
Assuntos
Dependovirus/genética , Variação Genética/genética , Vetores Genéticos/genética , Hiperlipoproteinemia Tipo II/genética , Receptores de LDL/genética , Desaminase APOBEC-1 , Animais , Colesterol/metabolismo , Citidina Desaminase/genética , Modelos Animais de Doenças , Terapia Genética , Células HEK293 , Humanos , Hiperlipoproteinemia Tipo II/metabolismo , Hiperlipoproteinemia Tipo II/terapia , Técnicas In Vitro , Masculino , Camundongos , Camundongos Knockout , Pró-Proteína Convertase 9 , Pró-Proteína Convertases/genética , Serina Endopeptidases/genética , Resultado do TratamentoRESUMO
Accurate prediction of the potential hepatotoxic nature of new pharmaceuticals remains highly challenging. Therefore, novel in vitro models with improved external validity are needed to investigate hepatic metabolism and timely identify any toxicity of drugs in humans. In this study, we examined the effects of diclofenac, as a model substance with a known risk of hepatotoxicity in vivo, in a dynamic multi-compartment bioreactor using primary human liver cells. Biotransformation pathways of the drug and possible effects on metabolic activities, morphology and cell transcriptome were evaluated. Formation rates of diclofenac metabolites were relatively stable over the application period of seven days in bioreactors exposed to 300 µM diclofenac (300 µM bioreactors (300 µM BR)), while in bioreactors exposed to 1000 µM diclofenac (1000 µM BR) metabolite concentrations declined drastically. The biochemical data showed a significant decrease in lactate production and for the higher dose a significant increase in ammonia secretion, indicating a dose-dependent effect of diclofenac application. The microarray analyses performed revealed a stable hepatic phenotype of the cells over time and the observed transcriptional changes were in line with functional readouts of the system. In conclusion, the data highlight the suitability of the bioreactor technology for studying the hepatotoxicity of drugs in vitro.
Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Reatores Biológicos , Técnicas de Cultura de Células/instrumentação , Diclofenaco/toxicidade , Hepatócitos/efeitos dos fármacos , Testes de Toxicidade/instrumentação , Anti-Inflamatórios não Esteroides/metabolismo , Células Cultivadas , Diclofenaco/metabolismo , Desenho de Equipamento , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , TranscriptomaRESUMO
Hyperhomocysteinemia, characterized by high plasma homocysteine levels, is recognized as an independent risk factor for cardiovascular diseases. The increased synthesis of homocysteine, a product of methionine metabolism involving B vitamins, and its slower intracellular utilization cause increased flux into the blood. Plasma homocysteine level is an important reflection of hepatic methionine metabolism and the rate of processes modified by B vitamins as well as different enzyme activity. Lowering homocysteine might offer therapeutic benefits. However, approximately 50% of hyperhomocysteinemic patients due to cystathionine-beta-synthase deficiency are biochemically responsive to pharmacological doses of B vitamins. Therefore, effective treatments to reduce homocysteine levels are needed, and gene therapy could provide a novel approach. We recently showed that hepatic expression of DYRK1A, a serine/threonine kinase, is negatively correlated with plasma homocysteine levels in cystathionine-beta-synthase deficient mice, a mouse model of hyperhomocysteinemia. Therefore, Dyrk1a is a good candidate for gene therapy to normalize homocysteine levels. We then used an adenoviral construct designed to restrict expression of DYRK1A to hepatocytes, and found decreased plasma homocysteine levels after hepatocyte-specific Dyrk1a gene transfer in hyperhomocysteinemic mice. The elevation of pyridoxal phosphate was consistent with the increase in cystathionine-beta-synthase activity. Commensurate with the decreased plasma homocysteine levels, targeted hepatic expression of DYRK1A resulted in elevated plasma paraoxonase-1 activity and apolipoprotein A-I levels, and rescued the Akt/GSK3 signaling pathways in aorta of mice, which can prevent homocysteine-induced endothelial dysfunction. These results demonstrate that hepatocyte-restricted Dyrk1a gene transfer can offer a useful therapeutic targets for the development of new selective homocysteine lowering therapy.
Assuntos
Aorta/metabolismo , Apolipoproteína A-I/sangue , Terapia Genética , Hepatócitos/metabolismo , Homocisteína , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Tirosina Quinases/biossíntese , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Aorta/patologia , Cistationina beta-Sintase/genética , Cistationina beta-Sintase/metabolismo , Homocisteína/sangue , Hiper-Homocisteinemia/sangue , Hiper-Homocisteinemia/genética , Hiper-Homocisteinemia/terapia , Camundongos , Camundongos Mutantes , Especificidade de Órgãos/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Tirosina Quinases/genética , Transdução Genética , Quinases DyrkRESUMO
Development of meso-diencephalic dopamine (mdDA) neurons requires the combined actions of the orphan nuclear receptor Nurr1 and the paired-like homeobox transcription factor Pitx3. Whereas all mdDA neurons require Nurr1 for expression of Th and survival, dependence on Pitx3 is displayed only by the mdDA subpopulation that will form the substantia nigra (SNc). Previously, we have demonstrated that Pitx3(-/-) embryos lack the expression of the retinoic acid (RA)-generating enzyme Ahd2, which is normally selectively expressed in the Pitx3-dependent DA neurons of the SNc. Restoring RA signaling in Pitx3(-/-) embryos revealed a selective dependence of SNc neurons on the presence of RA for differentiation into Th-positive neurons and maintenance throughout embryonic development. Whereas these data are suggestive of an important developmental role for RA in neurons of the SNc, it remained unclear whether other Nurr1 and Pitx3 target genes depend on RA signaling in a manner similar to Th. In the search for genes that were affected in Pitx3-deficient mdDA neurons and restored upon embryonic RA treatment, we provide evidence that Delta-like 1, D2R (Drd2) and Th are regulated by Pitx3 and RA signaling, which influences the mdDA terminal differentiated phenotype. Furthermore, we show that regulation of Ahd2-mediated RA signaling represents only one aspect of the Pitx3 downstream cascade, as Vmat2, Dat, Ahd2 (Aldh1a1), En1, En2 and Cck were unaffected by RA treatment and are (subset) specifically modulated by Pitx3. In conclusion, our data reveal several RA-dependent and -independent aspects of the Pitx3-regulated gene cascade, suggesting that Pitx3 acts on multiple levels in the molecular subset-specification of mdDA neurons.
Assuntos
Diencéfalo/citologia , Diencéfalo/embriologia , Redes Reguladoras de Genes/efeitos dos fármacos , Proteínas de Homeodomínio/metabolismo , Neurônios/metabolismo , Fatores de Transcrição/metabolismo , Tretinoína/farmacologia , Análise de Variância , Animais , Proteínas de Ligação ao Cálcio , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Feminino , Imunofluorescência , Redes Reguladoras de Genes/fisiologia , Genótipo , Hibridização In Situ , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Camundongos , Camundongos Knockout , Análise em Microsséries , Neurônios/fisiologia , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Reação em Cadeia da Polimerase , Gravidez , Receptores de Dopamina D2/metabolismo , Fatores de Transcrição/deficiênciaRESUMO
In this study, we investigated recurrent copy number variations (CNVs) in the 19p12 locus, which are associated with neurodevelopmental disorders. The two genes in this locus, ZNF675 and ZNF681, arose via gene duplication in primates, and their presence in several pathological CNVs in the human population suggests that either or both of these genes are required for normal human brain development. ZNF675 and ZNF681 are members of the Krüppel-associated box zinc finger (KZNF) protein family, a class of transcriptional repressors important for epigenetic silencing of specific genomic regions. About 170 primate-specific KZNFs are present in the human genome. Although KZNFs are primarily associated with repressing retrotransposon-derived DNA, evidence is emerging that they can be co-opted for other gene regulatory processes. We show that genetic deletion of ZNF675 causes developmental defects in cortical organoids, and our data suggest that part of the observed neurodevelopmental phenotype is mediated by a gene regulatory role of ZNF675 on the promoter of the neurodevelopmental gene Hes family BHLH transcription factor 1 (HES1). We also find evidence for the recently evolved regulation of genes involved in neurological disorders, microcephalin 1 and sestrin 3. We show that ZNF675 interferes with HES1 auto-inhibition, a process essential for the maintenance of neural progenitors. As a striking example of how some KZNFs have integrated into preexisting gene expression networks, these findings suggest the emergence of ZNF675 has caused a change in the balance of HES1 autoregulation. The association of ZNF675 CNV with human developmental disorders and ZNF675-mediated regulation of neurodevelopmental genes suggests that it evolved into an important factor for human brain development.
Assuntos
Primatas , Fatores de Transcrição HES-1 , Humanos , Animais , Fatores de Transcrição HES-1/genética , Fatores de Transcrição HES-1/metabolismo , Primatas/genética , Homeostase/fisiologia , Homeostase/genética , Variações do Número de Cópias de DNA/genética , Camundongos , Evolução Biológica , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismoRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with short- and long-term neurological complications. The variety of symptoms makes it difficult to unravel molecular mechanisms underlying neurological sequalae after coronavirus disease 2019 (COVID-19). Here we show that SARS-CoV-2 triggers the up-regulation of synaptic components and perturbs local electrical field potential. Using cerebral organoids, organotypic culture of human brain explants from individuals without COVID-19 and post-mortem brain samples from individuals with COVID-19, we find that neural cells are permissive to SARS-CoV-2 to a low extent. SARS-CoV-2 induces aberrant presynaptic morphology and increases expression of the synaptic components Bassoon, latrophilin-3 (LPHN3) and fibronectin leucine-rich transmembrane protein-3 (FLRT3). Furthermore, we find that LPHN3-agonist treatment with Stachel partially restored organoid electrical activity and reverted SARS-CoV-2-induced aberrant presynaptic morphology. Finally, we observe accumulation of relatively static virions at LPHN3-FLRT3 synapses, suggesting that local hindrance can contribute to synaptic perturbations. Together, our study provides molecular insights into SARS-CoV-2-brain interactions, which may contribute to COVID-19-related neurological disorders.