RESUMO
Macrophage-mediated inflammation is a major contributor to obesity-associated insulin resistance. The corepressor NCoR interacts with inflammatory pathway genes in macrophages, suggesting that its removal would result in increased activity of inflammatory responses. Surprisingly, we find that macrophage-specific deletion of NCoR instead results in an anti-inflammatory phenotype along with robust systemic insulin sensitization in obese mice. We present evidence that derepression of LXRs contributes to this paradoxical anti-inflammatory phenotype by causing increased expression of genes that direct biosynthesis of palmitoleic acid and ω3 fatty acids. Remarkably, the increased ω3 fatty acid levels primarily inhibit NF-κB-dependent inflammatory responses by uncoupling NF-κB binding and enhancer/promoter histone acetylation from subsequent steps required for proinflammatory gene activation. This provides a mechanism for the in vivo anti-inflammatory insulin-sensitive phenotype observed in mice with macrophage-specific deletion of NCoR. Therapeutic methods to harness this mechanism could lead to a new approach to insulin-sensitizing therapies.
Assuntos
Ácidos Graxos Ômega-3/metabolismo , Resistência à Insulina , Macrófagos/metabolismo , Correpressor 1 de Receptor Nuclear/metabolismo , Receptores Nucleares Órfãos/genética , Animais , Receptores X do Fígado , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Correpressor 1 de Receptor Nuclear/genéticaRESUMO
Retinitis pigmentosa (RP) is a heterogeneous disease and the main cause of vision loss within the group of inherited retinal diseases (IRDs). IRDs are a group of rare disorders caused by mutations in one or more of over 280 genes which ultimately result in blindness. Modifier genes play a key role in modulating disease phenotypes, and mutations in them can affect disease outcomes, rate of progression, and severity. Our previous studies have demonstrated that the nuclear hormone receptor 2 family e, member 3 (Nr2e3) gene reduced disease progression and loss of photoreceptor cell layers in RhoP23H-/- mice. This follow up, pharmacology study evaluates a longitudinal NR2E3 dose response in the clinically relevant heterozygous RhoP23H mouse. Reduced retinal degeneration and improved retinal morphology was observed 6 months following treatment evaluating three different NR2E3 doses. Histological and immunohistochemical analysis revealed regions of photoreceptor rescue in the treated retinas of RhoP23H+/- mice. Functional assessment by electroretinogram (ERG) showed attenuated photoreceptor degeneration with all doses. This study demonstrates the effectiveness of different doses of NR2E3 at reducing retinal degeneration and informs dose selection for clinical trials of RhoP23H-associated RP.
Assuntos
Modelos Animais de Doenças , Receptores Nucleares Órfãos , Degeneração Retiniana , Retinose Pigmentar , Animais , Retinose Pigmentar/genética , Retinose Pigmentar/metabolismo , Camundongos , Receptores Nucleares Órfãos/genética , Degeneração Retiniana/genética , Degeneração Retiniana/metabolismo , Degeneração Retiniana/etiologia , Eletrorretinografia , Retina/metabolismo , Retina/patologia , Terapia Genética/métodosRESUMO
Growing empirical evidence suggests that nutrition and bacterial metabolites might impact the systemic immune response in the context of disease and autoimmunity. We report that long-chain fatty acids (LCFAs) enhanced differentiation and proliferation of T helper 1 (Th1) and/or Th17 cells and impaired their intestinal sequestration via p38-MAPK pathway. Alternatively, dietary short-chain FAs (SCFAs) expanded gut T regulatory (Treg) cells by suppression of the JNK1 and p38 pathway. We used experimental autoimmune encephalomyelitis (EAE) as a model of T cell-mediated autoimmunity to show that LCFAs consistently decreased SCFAs in the gut and exacerbated disease by expanding pathogenic Th1 and/or Th17 cell populations in the small intestine. Treatment with SCFAs ameliorated EAE and reduced axonal damage via long-lasting imprinting on lamina-propria-derived Treg cells. These data demonstrate a direct dietary impact on intestinal-specific, and subsequently central nervous system-specific, Th cell responses in autoimmunity, and thus might have therapeutic implications for autoimmune diseases such as multiple sclerosis.
Assuntos
Autoimunidade/efeitos dos fármacos , Sistema Nervoso Central/imunologia , Gorduras na Dieta/farmacologia , Duodeno/imunologia , Encefalomielite Autoimune Experimental/etiologia , Ácidos Graxos/farmacologia , Linfopoese/efeitos dos fármacos , Subpopulações de Linfócitos T/efeitos dos fármacos , Animais , Gorduras na Dieta/toxicidade , Duodeno/metabolismo , Duodeno/microbiologia , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/metabolismo , Ácidos Graxos/química , Ácidos Graxos/toxicidade , Transplante de Microbiota Fecal , Microbioma Gastrointestinal/fisiologia , Regulação da Expressão Gênica/imunologia , Ácidos Láuricos/toxicidade , Receptores X do Fígado , Sistema de Sinalização das MAP Quinases , Camundongos , Peso Molecular , Receptores Nucleares Órfãos/biossíntese , Receptores Nucleares Órfãos/genética , Receptores Acoplados a Proteínas G/biossíntese , Receptores Acoplados a Proteínas G/genética , Baço/imunologia , Baço/patologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th17/imunologia , TranscriptomaRESUMO
Nuclear receptors are integrators of hormonal and nutritional signals, mediating changes to metabolic pathways within the body. Given that modulation of lipid and glucose metabolism has been linked to diseases including type 2 diabetes, obesity and atherosclerosis, a greater understanding of pathways that regulate metabolism in physiology and disease is crucial. The liver X receptors (LXRs) and the farnesoid X receptors (FXRs) are activated by oxysterols and bile acids, respectively. Mounting evidence indicates that these nuclear receptors have essential roles, not only in the regulation of cholesterol and bile acid metabolism but also in the integration of sterol, fatty acid and glucose metabolism.
Assuntos
Metabolismo dos Lipídeos/fisiologia , Receptores Nucleares Órfãos/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Aterosclerose/metabolismo , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Humanos , Receptores X do Fígado , Obesidade/metabolismo , Receptores Nucleares Órfãos/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Esteróis/metabolismo , Transcrição GênicaRESUMO
Hypercapnia occurs when the partial pressure of carbon dioxide (CO2) in the blood exceeds 45 mmHg. Hypercapnia is associated with several lung pathologies and is transcriptionally linked to suppression of immune and inflammatory signalling through poorly understood mechanisms. Here we propose Orphan Nuclear Receptor Family 4A (NR4A) family members NR4A2 and NR4A3 as potential transcriptional regulators of the cellular response to hypercapnia in monocytes. Using a THP-1 monocyte model, we investigated the sensitivity of NR4A family members to CO2 and the impact of depleting NR4A2 and NR4A3 on the monocyte response to buffered hypercapnia (10% CO2) using RNA-sequencing. We observed that NR4A2 and NR4A3 are CO2-sensitive transcription factors and that depletion of NR4A2 and NR4A3 led to reduced CO2-sensitivity of mitochondrial and heat shock protein (Hsp)-related genes, respectively. Several CO2-sensitive genes were, however, refractory to depletion of NR4A2 and NR4A3, indicating that NR4As regulate certain elements of the cellular response to buffered hypercapnia but that other transcription factors also contribute. Bioinformatic analysis of conserved CO2-sensitive genes implicated several novel putative CO2-sensitive transcription factors, of which the ETS Proto-Oncogene 1 Transcription Factor (ETS-1) was validated to show increased nuclear expression in buffered hypercapnia. These data give significant insights into the understanding of immune responses in patients experiencing hypercapnia.
Assuntos
Receptores Nucleares Órfãos , Receptores de Esteroides , Humanos , Receptores Nucleares Órfãos/genética , Monócitos/metabolismo , Hipercapnia , Dióxido de Carbono , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Receptores de Esteroides/metabolismo , Proteínas de Ligação a DNA , Receptores dos Hormônios TireóideosRESUMO
In this study, the ability of six limonoids from Trichilia prieuriana (Meliaceae) to activate the liver X receptor (LXR) was assessed. One of these limonoids, flindissone, was shown to activate LXR by reporter-gene assays. Flindissone is a ring-intact limonoid, structurally similar to sterol-like LXR ligands. In endogenous cellular settings, flindissone showed an activity profile that is characteristic of LXR agonists. It induced cholesterol efflux in THP-1 macrophages by increasing the cholesterol transporter ABCA1 and ABCG1 gene expression. In HepG2 cells, flindissone induced the expression of IDOL, an LXR-target gene that is associated with the downregulation of the LDL receptor. However, unlike synthetic and similarly to sterol-based LXR agonists, flindissone did not induce the expression of the SREBP1c gene, a major transcription factor regulating de novo lipogenesis. Additionally, flindissone also appeared to be able to inhibit post-translational activation of SREBP1c. The results presented here reveal a natural product as a new LXR agonist and point to an additional property of T. prieuriana and other plant extracts containing flindissone.
Assuntos
Limoninas , Meliaceae , Receptores X do Fígado/metabolismo , Limoninas/farmacologia , Receptores Nucleares Órfãos/genética , Colesterol/metabolismoRESUMO
Enhanced S-cone Syndrome (ESCS) is an autosomal recessive inherited retinal disease mostly associated with disease-causing variants in the NR2E3 gene. During retinal development in ESCS, rod photoreceptor precursors are misdirected to form photoreceptors similar to short-wavelength cones, or S-cones. Compared to a normal human retina, patients with ESCS have no rods and significantly increased numbers of S-cones. Night blindness is the main visual symptom, and visual acuity and color vision can be normal at early disease stages. Histology of donor eyes and adaptive optics imaging revealed increased S-cone density outside of the fovea compared to normal. Visual function testing reveals absent rod function and abnormally enhanced sensitivity to short-wavelength light. Unlike most retinal degenerative diseases, ESCS results in a gain in S-cone photoreceptor function. Research involving ESCS could improve understanding of this rare retinal condition and also shed light on the role of NR2E3 expression in photoreceptor survival.
Assuntos
Receptores Nucleares Órfãos , Degeneração Retiniana , Humanos , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Degeneração Retiniana/patologia , Retina/patologia , Células Fotorreceptoras Retinianas Cones/patologiaRESUMO
The nuclear receptors-liver X receptors (LXR α and ß) are potential therapeutic targets in cardiovascular and neurodegenerative diseases because of their key role in the regulation of lipid homeostasis and inflammatory processes. Specific oxy(phyto)sterols differentially modulate the transcriptional activity of LXRs providing opportunities to develop compounds with improved therapeutic characteristics. We isolated oxyphytosterols from Sargassum fusiforme and synthesized sidechain oxidized sterol derivatives. Five 24-oxidized sterols demonstrated a high potency for LXRα/ß activation in luciferase reporter assays and induction of LXR-target genes APOE, ABCA1 and ABCG1 involved in cellular cholesterol turnover in cultured cells: methyl 3ß-hydroxychol-5-en-24-oate (S1), methyl (3ß)-3-aldehydeoxychol-5-en-24-oate (S2), 24-ketocholesterol (S6), (3ß,22E)-3-hydroxycholesta-5,22-dien-24-one (N10) and fucosterol-24,28 epoxide (N12). These compounds induced SREBF1 but not SREBP1c-mediated lipogenic genes such as SCD1, ACACA and FASN in HepG2 cells or astrocytoma cells. Moreover, S2 and S6 enhanced cholesterol efflux from HepG2 cells. All five oxysterols induced production of the endogenous LXR agonists 24(S)-hydroxycholesterol by upregulating the CYP46A1, encoding the enzyme converting cholesterol into 24(S)-hydroxycholesterol; S1 and S6 may also act via the upregulation of desmosterol production. Thus, we identified five novel LXR-activating 24-oxidized sterols with a potential for therapeutic applications in neurodegenerative and cardiovascular diseases.
Assuntos
Doenças Neurodegenerativas , Fitosteróis , Humanos , Receptores X do Fígado , Esteróis/farmacologia , Receptores Nucleares Órfãos/genética , Hidroxicolesteróis , Doenças Neurodegenerativas/tratamento farmacológico , ColesterolRESUMO
Neuroinflammation and brain lipid imbalances are observed in Alzheimer's disease (AD). Tumor necrosis factor-α (TNFα) and the liver X receptor (LXR) signaling pathways are involved in both processes. However, limited information is currently available regarding their relationships in human brain pericytes (HBP) of the neurovascular unit. In cultivated HBP, TNFα activates the LXR pathway and increases the expression of one of its target genes, the transporter ATP-binding cassette family A member 1 (ABCA1), while ABCG1 is not expressed. Apolipoprotein E (APOE) synthesis and release are diminished. The cholesterol efflux is promoted, but is not inhibited, when ABCA1 or LXR are blocked. Moreover, as for TNFα, direct LXR activation by the agonist (T0901317) increases ABCA1 expression and the associated cholesterol efflux. However, this process is abolished when LXR/ABCA1 are both inhibited. Neither the other ABC transporters nor the SR-BI are involved in this TNFα-mediated lipid efflux regulation. We also report that inflammation increases ABCB1 expression and function. In conclusion, our data suggest that inflammation increases HBP protection against xenobiotics and triggers an LXR/ABCA1 independent cholesterol release. Understanding the molecular mechanisms regulating this efflux at the level of the neurovascular unit remains fundamental to the characterization of links between neuroinflammation, cholesterol and HBP function in neurodegenerative disorders.
Assuntos
Pericitos , Fator de Necrose Tumoral alfa , Humanos , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Pericitos/metabolismo , Receptores Nucleares Órfãos/genética , Doenças Neuroinflamatórias , Colesterol/metabolismo , Transdução de Sinais , Encéfalo/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismoRESUMO
BACKGROUND: Liver x receptor α (LXRα) is a ligand-activated transcription factor belonging to the nuclear receptor superfamily. Oxysterols (endogenous oxidized cholesterol derivatives) are the most potent endogenous LXRα-agonist. LXRα has a direct impact on several members of drug transporter superfamilies; ATP-binding cassette (ABC) and solute linked carrier (SLC). OBJECTIVE: The current study aimed to investigate the effect of LXRα-activation by either endogenous oxysterols or a synthetic LXRα-agonist (LXRa) such as TO901317 on hepatic and cardiac gene expression of ABCC10 and SLC17A5 drug transporters in an experimentally hypercholesterolemic rat model. METHODS: 48 male rats were divided randomly into four groups (n = 12); control group rats received vehicle; hypercholesterolemic group (HCH group) rats received diet contain 2.5% cholesterol &deoxycholic acid for 8 weeks; (LXRa group) rats were fed standard pellet chow for 8 weeks, then a single dose of LXRa was administered (IP) at a dose of 10 mg/kg; (HCH + LXRa group) rats received diet contain 2.5% cholesterol &deoxycholic acid for 8 weeks, then a single dose of LXRa was administered (IP) at a dose of 10 mg/kg. RESULTS: Our findings revealed that hypercholesterolemia and LXRa significantly activated LXRα to varying degrees in both hepatic and cardiac tissues with subsequent alteration of LXRα and ABCC10 gene expression. Whereas, SLC17A5 gene expression was primarily affected by elevated serum cholesterol level and unmediated via LXRα-activation. CONCLUSIONS: Accordingly, it was concluded that ABCC10 is a specific LXRα-target gene and that LXRα autoregulates its own expression in rats.
Assuntos
Hipercolesterolemia , Oxisteróis , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Colesterol/metabolismo , Ácido Desoxicólico , Hipercolesterolemia/genética , Hipercolesterolemia/metabolismo , Fígado/metabolismo , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Masculino , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Oxisteróis/metabolismo , RatosRESUMO
Cellular mechanisms that mediate steatohepatitis, an increasingly prevalent condition in the Western world for which no therapies are available, are poorly understood. Despite the fact that its synthetic agonists induce fatty liver, the liver X receptor (LXR) transcription factor remains a target of interest because of its anti-atherogenic, cholesterol removal, and anti-inflammatory activities. Here we show that tetratricopeptide repeat domain protein 39B (Ttc39b, C9orf52) (T39), a high-density lipoprotein gene discovered in human genome-wide association studies, promotes the ubiquitination and degradation of LXR. Chow-fed mice lacking T39 (T39(-/-)) display increased high-density lipoprotein cholesterol levels associated with increased enterocyte ATP-binding cassette transporter A1 (Abca1) expression and increased LXR protein without change in LXR messenger RNA. When challenged with a high fat/high cholesterol/bile salt diet, T39(-/-) mice or mice with hepatocyte-specific T39 deficiency show increased hepatic LXR protein and target gene expression, and unexpectedly protection from steatohepatitis and death. Mice fed a Western-type diet and lacking low-density lipoprotein receptor (Ldlr(-/-)T39(-/-)) show decreased fatty liver, increased high-density lipoprotein, decreased low-density lipoprotein, and reduced atherosclerosis. In addition to increasing hepatic Abcg5/8 expression and limiting dietary cholesterol absorption, T39 deficiency inhibits hepatic sterol regulatory element-binding protein 1 (SREBP-1, ADD1) processing. This is explained by an increase in microsomal phospholipids containing polyunsaturated fatty acids, linked to an LXRα-dependent increase in expression of enzymes mediating phosphatidylcholine biosynthesis and incorporation of polyunsaturated fatty acids into phospholipids. The preservation of endogenous LXR protein activates a beneficial profile of gene expression that promotes cholesterol removal and inhibits lipogenesis. T39 inhibition could be an effective strategy for reducing both steatohepatitis and atherosclerosis.
Assuntos
Aterosclerose/genética , Fígado Gorduroso/genética , Lipoproteínas HDL/deficiência , Lipoproteínas HDL/genética , Receptores Nucleares Órfãos/metabolismo , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Aterosclerose/prevenção & controle , Aterosclerose/terapia , Ácidos e Sais Biliares/metabolismo , Colesterol na Dieta/metabolismo , HDL-Colesterol/metabolismo , Dieta Hiperlipídica , Ácidos Graxos Insaturados/metabolismo , Fígado Gorduroso/prevenção & controle , Fígado Gorduroso/terapia , Feminino , Regulação da Expressão Gênica , Hepatócitos/metabolismo , Ligantes , Lipogênese/genética , Lipoproteínas/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Receptores X do Fígado , Masculino , Camundongos , Receptores Nucleares Órfãos/genética , Fosfatidilcolinas/biossíntese , Fosfatidilcolinas/metabolismo , Estabilidade Proteica , Proteólise , Receptores de LDL/deficiência , Receptores de LDL/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , UbiquitinaçãoRESUMO
Reprogramming of metabolic pathways in monocytes and macrophages can induce a proatherosclerotic inflammatory memory called trained innate immunity. Here, we have analyzed the role of the Liver X receptor (LXR), a crucial regulator of metabolism and inflammation, in oxidized low-density lipoprotein (oxLDL)-induced trained innate immunity. Human monocytes were incubated with LXR agonists, antagonists, and oxLDL for 24 h. After five days of resting time, cells were restimulated with the TLR-2 agonist Pam3cys. OxLDL priming induced the expression of LXRα but not LXRß. Pharmacologic LXR activation was enhanced, while LXR inhibition prevented the oxLDL-induced inflammatory response. Furthermore, LXR inhibition blocked the metabolic changes necessary for epigenetic reprogramming associated with trained immunity. In fact, enrichment of activating histone marks at the IL-6 and TNFα promotor was reduced following LXR inhibition. Based on the differential expression of the LXR isoforms, we inhibited LXRα and LXRß genes using siRNA in THP1 cells. As expected, siRNA-mediated knock-down of LXRα blocked the oxLDL-induced inflammatory response, while knock-down of LXRß had no effect. We demonstrate a specific and novel role of the LXRα isoform in the regulation of oxLDL-induced trained immunity. Our data reveal important aspects of LXR signaling in innate immunity with relevance to atherosclerosis formation.
Assuntos
Lipoproteínas LDL , Receptores Nucleares Órfãos , Humanos , Lipoproteínas LDL/metabolismo , Lipoproteínas LDL/farmacologia , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Macrófagos/metabolismo , Receptores Nucleares Órfãos/genética , RNA Interferente Pequeno/metabolismoRESUMO
Nuclear receptors are the regulatory molecules that mediate cellular signals as they interact with specific DNA sequences. NR5A2 is a member of NR5A subfamily having four members (Nr5a1-Nr5a4). NR5A2 shows involvement in diverse biological processes like reverse cholesterol transport, embryonic stem cell pluripotency, steroidogenesis, development and differentiation of embryo, and adult homeostasis. NR5A2 haploinsufficiency has been seen associated with chronic pancreatitis, pancreatic and gastrointestinal cancer. There is a close relationship between the progression of pancreatic cancer from chronic pancreatitis, NR5A2 serving a common link. NR5A2 activity is regulated by intracellular phospholipids, transcriptional coregulators and post-translational modifications. The specific ligand of NR5A2 is unknown hence called an orphan receptor, but specific phospholipids such as dilauroyl phosphatidylcholine and diundecanoyl phosphatidylcholine act as a ligand and they are established drug targets in various diseases. This review will focus on the NR5A2 structure, regulation of its activity, and role in biological processes and diseases. In future, need more emphasis on discovering small molecule agonists and antagonist, which act as a drug target for therapeutic applications.
Assuntos
Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores Citoplasmáticos e Nucleares/fisiologia , Animais , Sequência de Bases , Diferenciação Celular/genética , Humanos , Ligantes , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Receptores Nucleares Órfãos/fisiologia , Fosfatidilcolinas , Fosfolipídeos/metabolismo , Receptores Citoplasmáticos e Nucleares/genéticaRESUMO
Retinitis pigmentosa (RP) is an inherited retinal dystrophy that causes progressive vision loss. The G56R mutation in NR2E3 is the second most common mutation causing autosomal dominant (ad) RP, a transcription factor that is essential for photoreceptor development and maintenance. The G56R variant is exclusively responsible for all cases of NR2E3-associated adRP. Currently, there is no treatment for NR2E3-related or, other, adRP, but genome editing holds promise. A pertinent approach would be to specifically knockout the dominant mutant allele, so that the wild type allele can perform unhindered. In this study, we developed a CRISPR/Cas strategy to specifically knockout the mutant G56R allele of NR2E3 and performed a proof-of-concept study in induced pluripotent stem cells (iPSCs) of an adRP patient. We demonstrate allele-specific knockout of the mutant G56R allele in the absence of off-target events. Furthermore, we validated this knockout strategy in an exogenous overexpression system. Accordingly, the mutant G56R-CRISPR protein was truncated and mis-localized to the cytosol in contrast to the (peri)nuclear localizations of wild type or G56R NR2E3 proteins. Finally, we show, for the first time, that G56R iPSCs, as well as G56R-CRISPR iPSCs, can differentiate into NR2E3-expressing retinal organoids. Overall, we demonstrate that G56R allele-specific knockout by CRISPR/Cas could be a clinically relevant approach to treat NR2E3-associated adRP.
Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Genes Dominantes/genética , Mutação/genética , Retinose Pigmentar/genética , Alelos , Animais , Sequência de Bases , Células COS , Linhagem Celular , Chlorocebus aethiops , Edição de Genes/métodos , Células HEK293 , Humanos , Células-Tronco Pluripotentes Induzidas/fisiologia , Receptores Nucleares Órfãos/genética , Retina/fisiologiaRESUMO
Cardiovascular diseases (CVD) are still the first cause of death worldwide. Their main origin is the development of atherosclerotic plaque, which consists in the accumulation of lipids and inflammatory leucocytes within the vascular wall of large vessels. Beyond dyslipidemia, diabetes, obesity, hypertension and smoking, the alteration of circadian rhythms, in shift workers for instance, has recently been recognized as an additional risk factor. Accordingly, targeting a pro-atherogenic pathway at the right time window, namely chronotherapy, has proven its efficiency in reducing plaque progression without affecting healthy tissues in mice, thus providing the rationale of such an approach to treat CVD and to reduce drug side effects. Nuclear receptors are transcriptional factors involved in the control of many physiological processes. Among them, Rev-erbs and RORs control metabolic homeostasis, inflammatory processes and the biological clock. In this review, we discuss the opportunity to dampen atherosclerosis progression by targeting such ligand-activated core clock components in a (chrono-)therapeutic approach in order to treat CVD.
Assuntos
Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/metabolismo , Relógios Circadianos/genética , Suscetibilidade a Doenças , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Relógios Biológicos/genética , Biomarcadores , Doenças Cardiovasculares/diagnóstico , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Família Multigênica , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/genética , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/metabolismo , Especificidade de Órgãos/genética , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Transdução de SinaisRESUMO
Photoreceptor dysplasia, characterized by formation of folds and (pseudo-)rosettes in the outer retina, is associated with loss of functional nuclear receptor subfamily 2 group E member 3 (NR2E3) and neural retina leucine-zipper (NRL) in both humans and mice. A sensitized chemical mutagenesis study to identify genetic modifiers that suppress photoreceptor dysplasia in Nr2e3rd7mutant mice identified line Tvrm222, which exhibits a normal fundus appearance in the presence of the rd7 mutation. The Tvrm222 modifier of Nr2e3rd7/rd7 was localized to Chromosome 6 and identified as a missense mutation in the FERM domain containing 4B (Frmd4b) gene. The variant is predicted to cause the substitution of a serine residue 938 with proline (S938P). The Frmd4bTvrm222 allele was also found to suppress outer nuclear layer (ONL) rosettes in Nrl-/- mice. Fragmentation of the external limiting membrane (ELM), normally observed in rd7 and Nrl-/-mouse retinas, was absent in the presence of the Frmd4bTvrm222 allele. FRMD4B, a binding partner of cytohesin 3, is proposed to participate in cell junction remodeling. Its biological function in photoreceptor dysplasia has not been previously examined. In vitro experiments showed that the FRMD4B938P variant fails to be efficiently recruited to the cell surface upon insulin stimulation. In addition, we found a reduction in protein kinase B phosphorylation and increased levels of cell junction proteins, Catenin beta 1 and tight junction protein 1, associated with the cell membrane in Tvrm222 retinas. Taken together, this study reveals a critical role of FRMD4B in maintaining ELM integrity and in rescuing morphological abnormalities of the ONL in photoreceptor dysplasia.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Oftalmopatias Hereditárias/genética , Proteínas do Olho/genética , Receptores Nucleares Órfãos/genética , Degeneração Retiniana/genética , Transtornos da Visão/genética , Animais , Oftalmopatias Hereditárias/metabolismo , Oftalmopatias Hereditárias/patologia , Fundo de Olho , Humanos , Camundongos , Mutação de Sentido Incorreto , Domínios Proteicos/genética , Retina/crescimento & desenvolvimento , Retina/patologia , Células Fotorreceptoras Retinianas Cones/metabolismo , Células Fotorreceptoras Retinianas Cones/patologia , Degeneração Retiniana/metabolismo , Degeneração Retiniana/patologia , Segmento Externo das Células Fotorreceptoras da Retina , Transtornos da Visão/metabolismo , Transtornos da Visão/patologiaRESUMO
Hepatocarcinogenesis is a complicated process that is affected by a variety of microenvironmental factors, such as secretory chemokines and cell-extracellular matrix (ECM). Retinoic acid receptor-related orphan receptor (ROR)-α has been shown to attenuate tumor invasiveness by inducing suppressive cell microenvironment, and its low expression was associated with a worse prognosis in HCC patients. In the present study, we attempted to investigate the role and mechanism of the dominant transcript of ROR-α, ROR-α-1, in HCC development and progression. Among the four transcripts (ROR-α-1/-2/-3/-4), overexpression of ROR-α-1 dramatically suppressed the capacity of MHCC97H cells to proliferate, migrate and invade. We analyzed the differentially expressed genes in ROR-α-1-overexpressed and non-overexpressed MHCC97H cells, performed Gene Ontology (GO) enrichment analysis on these differentially-expressed genes, and found out that factors involved in the tumor microenvironment and ECM are related to the anti-tumor effects of ROR-α-1. Among these factors, chemokine CXCL5 was significantly downregulated by ROR-α-1 overexpression. Overexpression of ROR-α-1 remarkably inhibited the capacity of HCC cells to proliferate, migrate, invade, and downregulated the protein levels of ß-catenin, c-Myc, Cyclin D1, and N-cadherin, suggesting the tumor-suppressive role of ROR-α-1 in MHCC97H cells. Moreover, overexpression of CXCL5 dramatically attenuated the suppressive effects of cell proliferation, migration and invasion induced by ROR-α-1 overexpression in MHCC97H, suggesting that ROR-α-1 exerts its anti-tumor effects via downregulating CXCL5. In conclusion, we demonstrate the tumor-suppressive role of ROR-α-1 in MHCC97H cells and that ROR-α-1 might play a tumor-suppressive role via regulation of chemokine CXCL5.
Assuntos
Carcinoma Hepatocelular/genética , Movimento Celular/genética , Proliferação de Células/genética , Regulação para Baixo/genética , Neoplasias Hepáticas/genética , Invasividade Neoplásica/genética , Receptores Nucleares Órfãos/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Hepáticas/patologia , Invasividade Neoplásica/patologia , Microambiente Tumoral/genéticaRESUMO
Damage-induced long noncoding RNA (DINO) is a long noncoding RNA that directly interacts with p53 and thereby enhances p53 stability and activity in response to various cellular stresses. Here, we demonstrate that nuclear receptor subfamily 2 group E member 3 (NR2E3) plays a crucial role in maintaining active DINO epigenetic status for its proper induction and subsequent p53 activation. In acetaminophen (APAP)- or carbon tetrachloride-induced acute liver injuries, NR2E3 knockout (KO) mice exhibited far more severe liver injuries due to impaired DINO induction and p53 activation. Mechanistically, NR2E3 loss both in vivo and in vitro induced epigenetic DINO repression accompanied by reduced DINO chromatin accessibility. Furthermore, compared with the efficient reversal by a typical antidote N-acetylcysteine (NAC) treatment of APAP-induced liver injury in wild-type mice, the liver injury of NR2E3 KO mice was not effectively reversed, indicating that an intact NR2E3-DINO-p53-signaling axis is essential for NAC-mediated recovery against APAP-induced hepatotoxicity. These findings establish that NR2E3 is a critical component in p53 activation and a novel susceptibility factor to drug- or toxicant-induced acute liver injuries.-Khanal, T., Leung, Y.-K., Jiang, W., Timchenko, N., Ho, S.-M., Kim, K. NR2E3 is a key component in p53 activation by regulating a long noncoding RNA DINO in acute liver injuries.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Falência Hepática Aguda/metabolismo , Receptores Nucleares Órfãos/metabolismo , RNA Longo não Codificante/biossíntese , Transdução de Sinais , Proteína Supressora de Tumor p53/metabolismo , Acetaminofen/efeitos adversos , Acetaminofen/farmacologia , Acetilcisteína/farmacologia , Animais , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/patologia , Epigênese Genética/efeitos dos fármacos , Células Hep G2 , Humanos , Falência Hepática Aguda/induzido quimicamente , Falência Hepática Aguda/genética , Falência Hepática Aguda/patologia , Camundongos , Camundongos Knockout , Receptores Nucleares Órfãos/genética , RNA Longo não Codificante/genética , Proteína Supressora de Tumor p53/genéticaRESUMO
LXR-cofactor complexes activate the gene expression program responsible for cholesterol efflux in macrophages. Inflammation antagonizes this program, resulting in foam cell formation and atherosclerosis; however, the molecular mechanisms underlying this antagonism remain to be fully elucidated. We use promoter enrichment-quantitative mass spectrometry (PE-QMS) to characterize the composition of gene regulatory complexes assembled at the promoter of the lipid transporter Abca1 following downregulation of its expression. We identify a subset of proteins that show LXR ligand- and binding-dependent association with the Abca1 promoter and demonstrate they differentially control Abca1 expression. We determine that NCOA5 is linked to inflammatory Toll-like receptor (TLR) signaling and establish that NCOA5 functions as an LXR corepressor to attenuate Abca1 expression. Importantly, TLR3-LXR signal crosstalk promotes recruitment of NCOA5 to the Abca1 promoter together with loss of RNA polymerase II and reduced cholesterol efflux. Together, these data significantly expand our knowledge of regulatory inputs impinging on the Abca1 promoter and indicate a central role for NCOA5 in mediating crosstalk between pro-inflammatory and anti-inflammatory pathways that results in repression of macrophage cholesterol efflux.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/genética , Colesterol/metabolismo , Macrófagos/metabolismo , Coativadores de Receptor Nuclear/genética , Receptores Nucleares Órfãos/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Feminino , Regulação da Expressão Gênica , Inflamação/genética , Inflamação/metabolismo , Receptores X do Fígado , Espectrometria de Massas/métodos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Coativadores de Receptor Nuclear/metabolismo , Receptores Nucleares Órfãos/metabolismo , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Transdução de Sinais , Receptor 3 Toll-Like/genética , Receptor 3 Toll-Like/metabolismoRESUMO
PURPOSE: To evaluate the clinical phenotype of autosomal recessive NR2E3-related retinal dystrophy. METHODS: We retrospectively studied 11 patients carrying out at least 2 NR2E3 mutations; they had undergone comprehensive ophthalmological examination, fundus photography, optical coherence tomography, electrophysiological testing, and visual field at the Regional Reference Center for Hereditary Retinal Degenerations of the Eye Clinic in Florence. RESULTS: Five females and six males with a diagnosis of NR2E3-related retinal dystrophy were included in the study. All patients complained of nyctalopia. Visual acuity ranged from 0.00 logMAR to hand motion. Two patients presented bull's eye maculopathy, and one of these was characterized by a triple hyper-autofluorescent ring at the fundus autofluorescence examination. Three patients showed small yellowish dots and spots at the mid-periphery. One patient was characterized by widespread subretinal drusenoid deposits (SDD) at the posterior pole. Four patients showed vitreous abnormalities. Optical coherence tomography (OCT) examinations detected variable degrees of abnormal retinal lamination and schitic changes. Seven patients were compound heterozygous and four were homozygous for mutations in NR2E3. CONCLUSIONS: Our study confirmed high variable phenotype in autosomal recessive NR2E3-related retinal dystrophy. Bull's eye maculopathy, subretinal drusenoid deposits, and foveal hypoplasia represent novel clinical findings in NR2E3-related retinal dystrophy. Macular involvement was detectable in all the patients, and the abnormal foveal avascular zone (FAZ) supports the role of NR2E3 in retinal development.