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1.
Immunity ; 51(6): 1074-1087.e9, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31784108

RESUMO

Infections induce complex host responses linked to antiviral defense, inflammation, and tissue damage and repair. We hypothesized that the liver, as a central metabolic hub, may orchestrate systemic metabolic changes during infection. We infected mice with chronic lymphocytic choriomeningitis virus (LCMV), performed RNA sequencing and proteomics of liver tissue, and integrated these data with serum metabolomics at different infection phases. Widespread reprogramming of liver metabolism occurred early after infection, correlating with type I interferon (IFN-I) responses. Viral infection induced metabolic alterations of the liver that depended on the interferon alpha/beta receptor (IFNAR1). Hepatocyte-intrinsic IFNAR1 repressed the transcription of metabolic genes, including Otc and Ass1, which encode urea cycle enzymes. This led to decreased arginine and increased ornithine concentrations in the circulation, resulting in suppressed virus-specific CD8+ T cell responses and ameliorated liver pathology. These findings establish IFN-I-induced modulation of hepatic metabolism and the urea cycle as an endogenous mechanism of immunoregulation. VIDEO ABSTRACT.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Interferon Tipo I/imunologia , Fígado/metabolismo , Vírus da Coriomeningite Linfocítica/imunologia , Receptor de Interferon alfa e beta/metabolismo , Animais , Arginina/sangue , Linhagem Celular , Chlorocebus aethiops , Cricetinae , Feminino , Hepatócitos/metabolismo , Fígado/imunologia , Fígado/virologia , Coriomeningite Linfocítica/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ornitina/sangue , Ornitina Carbamoiltransferase/genética , Transdução de Sinais/imunologia , Ureia/metabolismo , Células Vero
2.
Nat Chem Biol ; 16(4): 469-478, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32152546

RESUMO

Solute carriers (SLCs) are the largest family of transmembrane transporters in humans and are major determinants of cellular metabolism. Several SLCs have been shown to be required for the uptake of chemical compounds into cellular systems, but systematic surveys of transporter-drug relationships in human cells are currently lacking. We performed a series of genetic screens in a haploid human cell line against 60 cytotoxic compounds representative of the chemical space populated by approved drugs. By using an SLC-focused CRISPR-Cas9 library, we identified transporters whose absence induced resistance to the drugs tested. This included dependencies involving the transporters SLC11A2/SLC16A1 for artemisinin derivatives and SLC35A2/SLC38A5 for cisplatin. The functional dependence on SLCs observed for a significant proportion of the screened compounds suggests a widespread role for SLCs in the uptake and cellular activity of cytotoxic drugs and provides an experimentally validated set of SLC-drug associations for a number of clinically relevant compounds.


Assuntos
Resistência a Medicamentos/genética , Proteínas Carreadoras de Solutos/metabolismo , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Antineoplásicos , Fenômenos Bioquímicos , Transporte Biológico/genética , Transporte Biológico/fisiologia , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Resistência a Medicamentos/fisiologia , Testes Genéticos , Humanos , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Transporte Proteico/fisiologia , Proteínas Carreadoras de Solutos/fisiologia , Simportadores/genética , Simportadores/metabolismo
3.
Nat Metab ; 3(5): 651-664, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33972798

RESUMO

Metabolism negotiates cell-endogenous requirements of energy, nutrients and building blocks with the immediate environment to enable various processes, including growth and differentiation. While there is an increasing number of examples of crosstalk between metabolism and chromatin, few involve uptake of exogenous metabolites. Solute carriers (SLCs) represent the largest group of transporters in the human genome and are responsible for the transport of a wide variety of substrates, including nutrients and metabolites. We aimed to investigate the possible involvement of SLC-mediated solutes uptake and cellular metabolism in regulating cellular epigenetic states. Here, we perform a CRISPR-Cas9 transporter-focused genetic screen and a metabolic compound library screen for the regulation of BRD4-dependent chromatin states in human myeloid leukaemia cells. Intersection of the two orthogonal approaches reveal that loss of transporters involved with purine transport or inhibition of de novo purine synthesis lead to dysfunction of BRD4-dependent transcriptional regulation. Through mechanistic characterization of the metabolic circuitry, we elucidate the convergence of SLC-mediated purine uptake and de novo purine synthesis on BRD4-chromatin occupancy. Moreover, adenine-related metabolite supplementation effectively restores BRD4 functionality on purine impairment. Our study highlights the specific role of purine/adenine metabolism in modulating BRD4-dependent epigenetic states.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cromatina/metabolismo , Proteínas de Transporte de Nucleosídeos/metabolismo , Purinas/metabolismo , Proteínas Carreadoras de Solutos/metabolismo , Fatores de Transcrição/metabolismo , Adenina/metabolismo , Vias Biossintéticas , Proteínas de Ciclo Celular/antagonistas & inibidores , Linhagem Celular , Cromatina/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Proteínas de Membrana Transportadoras , Modelos Biológicos , Proteínas Carreadoras de Solutos/genética , Fatores de Transcrição/antagonistas & inibidores , Transcrição Gênica
4.
Nat Commun ; 11(1): 6145, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33262325

RESUMO

About a thousand genes in the human genome encode for membrane transporters. Among these, several solute carrier proteins (SLCs), representing the largest group of transporters, are still orphan and lack functional characterization. We reasoned that assessing genetic interactions among SLCs may be an efficient way to obtain functional information allowing their deorphanization. Here we describe a network of strong genetic interactions indicating a contribution to mitochondrial respiration and redox metabolism for SLC25A51/MCART1, an uncharacterized member of the SLC25 family of transporters. Through a combination of metabolomics, genomics and genetics approaches, we demonstrate a role for SLC25A51 as enabler of mitochondrial import of NAD, showcasing the potential of genetic interaction-driven functional gene deorphanization.


Assuntos
Epistasia Genética , Mitocôndrias/metabolismo , NAD/metabolismo , Proteína Desacopladora 1/metabolismo , Transporte Biológico , Humanos , Mitocôndrias/genética , Oxirredução , Proteína Desacopladora 1/genética
5.
JCI Insight ; 5(5)2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32106111

RESUMO

Patients with active acromegaly (ACRO) exhibit low hepatocellular lipids (HCL), despite pronounced insulin resistance (IR). This contrasts the strong association of IR with nonalcoholic fatty liver disease in the general population. Since low HCL levels in ACRO might be caused by changes in oxidative substrate metabolism, we investigated mitochondrial activity and plasma metabolomics/lipidomics in active ACRO. Fifteen subjects with ACRO and seventeen healthy controls, matched for age, BMI, sex, and body composition, underwent 31P/1H-7-T MR spectroscopy of the liver and skeletal muscle as well as plasma metabolomic profiling and an oral glucose tolerance test. Subjects with ACRO showed significantly lower HCL levels, but the ATP synthesis rate was significantly increased compared with that in controls. Furthermore, a decreased ratio of unsaturated-to-saturated intrahepatocellular fatty acids was found in subjects with ACRO. Within assessed plasma lipids, lipidomics, and metabolomics, decreased carnitine species also indicated increased mitochondrial activity. We therefore concluded that excess of growth hormone (GH) in humans counteracts HCL accumulation by increased hepatic ATP synthesis. This was accompanied by a decreased ratio of unsaturated-to-saturated lipids in hepatocytes and by a metabolomic profile, reflecting the increase in mitochondrial activity. Thus, these findings help to better understanding of GH-regulated antisteatotic pathways and provide a better insight into potentially novel therapeutic targets for treating NAFLD.


Assuntos
Acromegalia/metabolismo , Trifosfato de Adenosina/biossíntese , Metabolismo dos Lipídeos , Fígado/metabolismo , Adulto , Feminino , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo
6.
Nat Genet ; 51(6): 990-998, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31133746

RESUMO

The histone acetyl reader bromodomain-containing protein 4 (BRD4) is an important regulator of chromatin structure and transcription, yet factors modulating its activity have remained elusive. Here we describe two complementary screens for genetic and physical interactors of BRD4, which converge on the folate pathway enzyme MTHFD1 (methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1). We show that a fraction of MTHFD1 resides in the nucleus, where it is recruited to distinct genomic loci by direct interaction with BRD4. Inhibition of either BRD4 or MTHFD1 results in similar changes in nuclear metabolite composition and gene expression; pharmacological inhibitors of the two pathways synergize to impair cancer cell viability in vitro and in vivo. Our finding that MTHFD1 and other metabolic enzymes are chromatin associated suggests a direct role for nuclear metabolism in the control of gene expression.


Assuntos
Ácido Fólico/metabolismo , Regulação da Expressão Gênica , Metilenotetra-Hidrofolato Desidrogenase (NADP)/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Cromatina/genética , Técnicas de Inativação de Genes , Humanos , Mutação com Perda de Função , Ligação Proteica , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Transporte Proteico , Transdução de Sinais , Transcrição Gênica
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