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1.
Cell Death Dis ; 14(10): 661, 2023 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-37816735

RESUMO

We previously found that global deletion of the mitochondrial enzyme arginase 2 (A2) limits optic nerve crush (ONC)-induced neuronal death. Herein, we examined the cell-specific role of A2 in this pathology by studies using wild type (WT), neuronal-specific calbindin 2 A2 KO (Calb2cre/+ A2 f/f), myeloid-specific A2 KO (LysMcre/+ A2f/f), endothelial-specific A2 KO (Cdh5cre/+ A2f/f), and floxed controls. We also examined the impact of A2 overexpression on mitochondrial function in retinal neuronal R28 cells. Immunolabeling showed increased A2 expression in ganglion cell layer (GCL) neurons of WT mice within 6 h-post injury and inner retinal neurons after 7 days. Calb2 A2 KO mice showed improved neuronal survival, decreased TUNEL-positive neurons, and improved retinal function compared to floxed littermates. Neuronal loss was unchanged by A2 deletion in myeloid or endothelial cells. We also found increased expression of neurotrophins (BDNF, FGF2) and improved survival signaling (pAKT, pERK1/2) in Calb2 A2 KO retinas within 24-hour post-ONC along with suppression of inflammatory mediators (IL1ß, TNFα, IL6, and iNOS) and apoptotic markers (cleavage of caspase3 and PARP). ONC increased GFAP and Iba1 immunostaining in floxed controls, and Calb2 A2 KO dampened this effect. Overexpression of A2 in R28 cells increased Drp1 expression, and decreased mitochondrial respiration, whereas ABH-induced inhibition of A2 decreased Drp1 expression and improved mitochondrial respiration. Finally, A2 overexpression or excitotoxic treatment with glutamate significantly impaired mitochondrial function in R28 cells as shown by significant reductions in basal respiration, maximal respiration, and ATP production. Further, glutamate treatment of A2 overexpressing cells did not induce further deterioration in their mitochondrial function, indicating that A2 overexpression or glutamate insult induce comparable alterations in mitochondrial function. Our data indicate that neuronal A2 expression is neurotoxic after injury, and A2 deletion in Calb2 expressing neurons limits ONC-induced retinal neurodegeneration and improves visual function.


Assuntos
Arginase , Traumatismos do Nervo Óptico , Animais , Camundongos , Apoptose , Arginase/genética , Arginase/metabolismo , Calbindina 2 , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Glutamatos , Compressão Nervosa , Nervo Óptico/metabolismo , Traumatismos do Nervo Óptico/metabolismo
2.
Gastroenterology ; 165(1): 71-87, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37030336

RESUMO

BACKGROUND & AIMS: Visceral smooth muscle cells (SMCs) are an integral component of the gastrointestinal (GI) tract that regulate GI motility. SMC contraction is regulated by posttranslational signaling and the state of differentiation. Impaired SMC contraction is associated with significant morbidity and mortality, but the mechanisms regulating SMC-specific contractile gene expression, including the role of long noncoding RNAs (lncRNAs), remain largely unexplored. Herein, we reveal a critical role of Carmn (cardiac mesoderm enhancer-associated noncoding RNA), an SMC-specific lncRNA, in regulating visceral SMC phenotype and contractility of the GI tract. METHODS: Genotype-Tissue Expression and publicly available single-cell RNA sequencing (scRNA-seq) data sets from embryonic, adult human, and mouse GI tissues were interrogated to identify SMC-specific lncRNAs. The functional role of Carmn was investigated using novel green fluorescent protein (GFP) knock-in (KI) reporter/knock-out (KO) mice. Bulk RNA-seq and single nucleus RNA sequencing (snRNA-seq) of colonic muscularis were used to investigate underlying mechanisms. RESULTS: Unbiased in silico analyses and GFP expression patterns in Carmn GFP KI mice revealed that Carmn is highly expressed in GI SMCs in humans and mice. Premature lethality was observed in global Carmn KO and inducible SMC-specific KO mice due to GI pseudo-obstruction and severe distension of the GI tract, with dysmotility in cecum and colon segments. Histology, GI transit, and muscle myography analysis revealed severe dilation, significantly delayed GI transit, and impaired GI contractility in Carmn KO vs control mice. Bulk RNA-seq of GI muscularis revealed that loss of Carmn promotes SMC phenotypic switching, as evidenced by up-regulation of extracellular matrix genes and down-regulation of SMC contractile genes, including Mylk, a key regulator of SMC contraction. snRNA-seq further revealed SMC Carmn KO not only compromised myogenic motility by reducing contractile gene expression but also impaired neurogenic motility by disrupting cell-cell connectivity in the colonic muscularis. These findings may have translational significance, because silencing CARMN in human colonic SMCs significantly attenuated contractile gene expression, including MYLK, and decreased SMC contractility. Luciferase reporter assays showed that CARMN enhances the transactivation activity of the master regulator of SMC contractile phenotype, myocardin, thereby maintaining the GI SMC myogenic program. CONCLUSIONS: Our data suggest that Carmn is indispensable for maintaining GI SMC contractile function in mice and that loss of function of CARMN may contribute to human visceral myopathy. To our knowledge this is the first study showing an essential role of lncRNA in the regulation of visceral SMC phenotype.


Assuntos
Contração Muscular , Músculo Liso , RNA Longo não Codificante , Animais , Humanos , Camundongos , Diferenciação Celular , Células Cultivadas , Camundongos Knockout , Miócitos de Músculo Liso/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
3.
J Neuroinflammation ; 20(1): 14, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36691048

RESUMO

BACKGROUND: We have investigated the efficacy of a new strategy to limit pathological retinal neovascularization (RNV) during ischemic retinopathy by targeting the cholesterol metabolizing enzyme acyl-coenzyme A: cholesterol transferase 1 (ACAT1). Dyslipidemia and cholesterol accumulation have been strongly implicated in promoting subretinal NV. However, little is known about the role of cholesterol metabolism in RNV. Here, we tested the effects of inhibiting ACAT1 on pathological RNV in the mouse model of oxygen-induced retinopathy (OIR). METHODS: In vivo studies used knockout mice that lack the receptor for LDL cholesterol (LDLR-/-) and wild-type mice. The wild-type mice were treated with a specific inhibitor of ACAT1, K604 (10 mg/kg, i.p) or vehicle (PBS) during OIR. In vitro studies used human microglia exposed to oxygen-glucose deprivation (OGD) and treated with the ACAT1 inhibitor (1 µM) or PBS. RESULTS: Analysis of OIR retinas showed that increased expression of inflammatory mediators and pathological RNV were associated with significant increases in expression of the LDLR, increased accumulation of neutral lipids, and formation of toxic levels of cholesterol ester (CE). Deletion of the LDLR completely blocked OIR-induced RNV and significantly reduced the AVA. The OIR-induced increase in CE formation was accompanied by significant increases in expression of ACAT1, VEGF and inflammatory factors (TREM1 and MCSF) (p < 0.05). ACAT1 was co-localized with TREM1, MCSF, and macrophage/microglia makers (F4/80 and Iba1) in areas of RNV. Treatment with K604 prevented retinal accumulation of neutral lipids and CE formation, inhibited RNV, and decreased the AVA as compared to controls (p < 0.05). The treatment also blocked upregulation of LDLR, ACAT1, TREM1, MCSF, and inflammatory cytokines but did not alter VEGF expression. K604 treatment of microglia cells also blocked the effects of OGD in increasing expression of ACAT1, TREM1, and MCSF without altering VEGF expression. CONCLUSIONS: OIR-induced RNV is closely associated with increases in lipid accumulation and CE formation along with increased expression of LDLR, ACAT1, TREM1, and MCSF. Inhibiting ACAT1 blocked these effects and limited RNV independently of alterations in VEGF expression. This pathway offers a novel strategy to limit vascular injury during ischemic retinopathy.


Assuntos
Neovascularização Retiniana , Retinopatia da Prematuridade , Recém-Nascido , Animais , Humanos , Camundongos , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/patologia , Neovascularização Retiniana/prevenção & controle , Retinopatia da Prematuridade/metabolismo , Receptor Gatilho 1 Expresso em Células Mieloides , Fator A de Crescimento do Endotélio Vascular/metabolismo , Oxigênio/metabolismo , Colesterol , Transferases , Coenzima A/efeitos adversos , Lipídeos/efeitos adversos , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Acetil-CoA C-Acetiltransferase
4.
Gen Relativ Gravit ; 54(12): 156, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36465478

RESUMO

Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal-including inflation, phase transitions, topological defects, as well as primordial black holes-and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe.

5.
Front Cardiovasc Med ; 9: 900640, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35722112

RESUMO

Diabetic retinopathy (DR) is the leading cause of vision loss in working age adults. Understanding the retinal metabolic response to circulating high glucose levels in diabetic patients is critical for development of new therapeutics to treat DR. Measuring retinal metabolic function using the Seahorse analyzer is a promising technique to investigate the effect of hyperglycemia on retinal glycolysis and mitochondrial respiration. Here, we analyzed the retinal metabolic function in young and old diabetic and control mice. We also compared the expression of key glycolytic enzymes between the two groups. The Seahorse XF analyzer was used to measure the metabolic function of retina explants from young and old type 1 diabetic Akita (Ins2Akita ) mice and their control littermates. Rate-limiting glycolytic enzymes were analyzed in retina lysates from the two age groups by Western blotting. Retinas from young adult Akita mice showed a decreased glycolytic response as compared to control littermates. However, this was not observed in the older mice. Western blotting analysis showed decreased expression of the glycolytic enzyme PFKFB3 in the young Akita mice retinas. Measurement of the oxygen consumption rate showed no difference in retinal mitochondrial respiration between Akita and WT littermates under normal glucose conditions ex vivo despite mitochondrial fragmentation in the Akita retinas as examined by electron microscopy. However, Akita mice retinas showed decreased mitochondrial respiration under glucose-free conditions. In conclusion, diabetic retinas display a decreased glycolytic response during the early course of diabetes which is accompanied by a reduction in PFKFB3. Diabetic retinas exhibit decreased mitochondrial respiration under glucose deprivation.

6.
Gen Relativ Gravit ; 54(1): 3, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35221342

RESUMO

The science objectives of the LISA mission have been defined under the implicit assumption of a 4-years continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of ≈ 0.75 , which would reduce the effective span of usable data to 3 years. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. We explore various observational scenarios to assess the impact of mission duration on the main science objectives of the mission. We find that the science investigations most affected by mission duration concern the search for seed black holes at cosmic dawn, as well as the study of stellar-origin black holes and of their formation channels via multi-band and multi-messenger observations. We conclude that an extension to 6 years of mission operations is recommended.

7.
Mol Biol Cell ; 32(22): ar39, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34668730

RESUMO

The electron transport chain (ETC) is a well-studied and highly conserved metabolic pathway that produces ATP through generation of a proton gradient across the inner mitochondrial membrane coupled to oxidative phosphorylation. ETC mutations are associated with a wide array of human disease conditions and to aging-related phenotypes in a number of different organisms. In this study, we sought to better understand the role of the ETC in aging using a yeast model. A panel of ETC mutant strains that fail to survive starvation was used to isolate suppressor mutants that survive. These suppressors tend to fall into major nutrient sensing and signaling pathways, suggesting that the ETC is involved in proper starvation signaling to these pathways in yeast. These suppressors also partially restore ETC-associated gene expression and pH homeostasis defects, though it remains unclear whether these phenotypes directly cause the suppression or are simply effects. This work further highlights the complex cellular network connections between metabolic pathways and signaling events in the cell and their potential roles in aging and age-related diseases.


Assuntos
Transporte de Elétrons/genética , Mutação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/fisiologia , Citosol/química , Citosol/metabolismo , Transporte de Elétrons/fisiologia , Regulação Fúngica da Expressão Gênica , Genoma Mitocondrial , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Proteínas de Saccharomyces cerevisiae/genética , Transdução de Sinais , Fatores de Transcrição/genética
8.
Environ Sci Technol ; 55(14): 10056-10066, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34236189

RESUMO

Tailings dam failures can cause devastation to the environment, loss of human life, and require expensive remediation. A promising approach for de-risking brucite-bearing ultramafic tailings is in situ cementation via carbon dioxide (CO2) mineralization, which also sequesters this greenhouse gas within carbonate minerals. In cylindrical test experiments, brucite [Mg(OH)2] carbonation was accelerated by coupling organic and inorganic carbon cycling. Waste organics generated CO2 concentrations similar to that of flue gas (up to 19%). The abundance of brucite (2-10 wt %) had the greatest influence on tailings cementation as evidenced by the increase in total inorganic carbon (TIC; +0.17-0.84%). Brucite consumption ranged from 64-84% of its initial abundance and was mainly influenced by water availability. Higher moisture contents (e.g., 80% saturation) and finer grain sizes (e.g., clay-silt) that allowed for a better distribution of water resulted in greater brucite carbonation. Furthermore, pore clogging and surface passivation by Mg-carbonates may have slowed brucite carbonation over the 10 weeks. Unconfined compressive strengths ranged from 0.4-6.9 MPa and would be sufficient in most scenarios to adequately stabilize tailings. Our study demonstrates the potential for stabilizing brucite-bearing mine tailings through in situ cementation while sequestering CO2.


Assuntos
Sequestro de Carbono , Cimentação , Dióxido de Carbono , Carbonatos , Humanos , Hidróxido de Magnésio
9.
Proc Natl Acad Sci U S A ; 118(7)2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33563757

RESUMO

Sepsis is a major cause of mortality in intensive care units, which results from a severely dysregulated inflammatory response that ultimately leads to organ failure. While antibiotics can help in the early stages, effective strategies to curtail inflammation remain limited. The high mobility group (HMG) proteins are chromosomal proteins with important roles in regulating gene transcription. While HMGB1 has been shown to play a role in sepsis, the role of other family members including HMGXB4 remains unknown. We found that expression of HMGXB4 is strongly induced in response to lipopolysaccharide (LPS)-elicited inflammation in murine peritoneal macrophages. Genetic deletion of Hmgxb4 protected against LPS-induced lung injury and lethality and cecal ligation and puncture (CLP)-induced lethality in mice, and attenuated LPS-induced proinflammatory gene expression in cultured macrophages. By integrating genome-wide transcriptome profiling and a publicly available ChIP-seq dataset, we identified HMGXB4 as a transcriptional activator that regulates the expression of the proinflammatory gene, Nos2 (inducible nitric oxide synthase 2) by binding to its promoter region, leading to NOS2 induction and excessive NO production and tissue damage. Similar to Hmgxb4 ablation in mice, administration of a pharmacological inhibitor of NOS2 robustly decreased LPS-induced pulmonary vascular permeability and lethality in mice. Additionally, we identified the cell adhesion molecule, ICAM1, as a target of HMGXB4 in endothelial cells that facilitates inflammation by promoting monocyte attachment. In summary, our study reveals a critical role of HMGXB4 in exacerbating endotoxemia via transcriptional induction of Nos2 and Icam1 gene expression and thus targeting HMGXB4 may be an effective therapeutic strategy for the treatment of sepsis.


Assuntos
Endotoxemia/metabolismo , Animais , Células Endoteliais/metabolismo , Endotoxemia/etiologia , Endotoxemia/genética , Feminino , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , Lipopolissacarídeos/toxicidade , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Transcriptoma
10.
Front Physiol ; 12: 793251, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35264975

RESUMO

Alveolar-capillary leak is a hallmark of the acute respiratory distress syndrome (ARDS), a potentially lethal complication of severe sepsis, trauma and pneumonia, including COVID-19. Apart from barrier dysfunction, ARDS is characterized by hyper-inflammation and impaired alveolar fluid clearance (AFC), which foster the development of pulmonary permeability edema and hamper gas exchange. Tumor Necrosis Factor (TNF) is an evolutionarily conserved pleiotropic cytokine, involved in host immune defense against pathogens and cancer. TNF exists in both membrane-bound and soluble form and its mainly -but not exclusively- pro-inflammatory and cytolytic actions are mediated by partially overlapping TNFR1 and TNFR2 binding sites situated at the interface between neighboring subunits in the homo-trimer. Whereas TNFR1 signaling can mediate hyper-inflammation and impaired barrier function and AFC in the lungs, ligand stimulation of TNFR2 can protect from ventilation-induced lung injury. Spatially distinct from the TNFR binding sites, TNF harbors within its structure a lectin-like domain that rather protects lung function in ARDS. The lectin-like domain of TNF -mimicked by the 17 residue TIP peptide- represents a physiological mediator of alveolar-capillary barrier protection. and increases AFC in both hydrostatic and permeability pulmonary edema animal models. The TIP peptide directly activates the epithelial sodium channel (ENaC) -a key mediator of fluid and blood pressure control- upon binding to its α subunit, which is also a part of the non-selective cation channel (NSC). Activity of the lectin-like domain of TNF is preserved in complexes between TNF and its soluble TNFRs and can be physiologically relevant in pneumonia. Antibody- and soluble TNFR-based therapeutic strategies show considerable success in diseases such as rheumatoid arthritis, psoriasis and inflammatory bowel disease, but their chronic use can increase susceptibility to infection. Since the lectin-like domain of TNF does not interfere with TNF's anti-bacterial actions, while exerting protective actions in the alveolar-capillary compartments, it is currently evaluated in clinical trials in ARDS and COVID-19. A more comprehensive knowledge of the precise role of the TNFR binding sites versus the lectin-like domain of TNF in lung injury, tissue hypoxia, repair and remodeling may foster the development of novel therapeutics for ARDS.

11.
Neuropsychopharmacology ; 45(11): 1896-1908, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32599605

RESUMO

Prenatal infection during pregnancy increases the risk for developing neuropsychiatric disorders such as schizophrenia. This is linked to an inflammatory microglial phenotype in the offspring induced by maternal immune activation (MIA). Microglia are crucial for brain development and maintenance of neuronal niches, however, whether and how their activation is involved in the regulation of neurodevelopment remains unclear. Here, we used a MIA rodent model in which polyinosinic: polycytidylic acid (poly (I:C)) was injected into pregnant mice. We found fewer parvalbumin positive (PV+) cells and impaired GABAergic transmission in the dentate gyrus (DG), accompanied by schizophrenia-like behavior in the adult offspring. Minocycline, a potent inhibitor of microglia activation, successfully prevented the above-mentioned deficits in the offspring. Furthermore, by using microglia-specific arginase 1 (Arg1) ablation as well as overexpression in DG, we identified a critical role of Arg1 in microglia activation to protect against poly (I:C) imparted neuropathology and altered behavior in offspring. Taken together, our results highlight that Arg1-mediated alternative activation of microglia are potential therapeutic targets for psychiatric disorders induced by MIA.


Assuntos
Efeitos Tardios da Exposição Pré-Natal , Esquizofrenia , Animais , Arginase , Comportamento Animal , Giro Denteado , Modelos Animais de Doenças , Feminino , Camundongos , Microglia , Fenótipo , Gravidez
12.
J Psychiatr Res ; 114: 55-66, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31039481

RESUMO

Chronic stress-induced anxiety disorder is a highly-prevalent, modern social disease in which oxidative stress plays an important role. It is necessary to determine the underlying mechanisms governing this disorder to establish an effective treatment target for anxiety disorders. In this study, we examined the behavioral changes in mice subjected to chronic mild stress (CMS). We found that CMS exposure leads to anxiety-like phenotypes and increased levels of oxidative stress in the ventral hippocampus of mice. Furthermore, CMS increased the excitatory synaptic transmission of pyramidal cells in the ventral CA1 (vCA1). Administration of 4-hydroxy-3-methoxy-acetophenone (apocynin), an inhibitor of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, clearly ameliorated the changes induced by CMS exposure. In addition, our results of behavioral tests and analyses of reactive oxygen species (ROS) using NOX2-deficient mice indicate that CMS-induced enhanced oxidative stress level is primarily caused by the increased expression of NOX2. NOX2-derived oxidative stress can serve as a target for anxiety therapy led by chronic stress.


Assuntos
Acetofenonas/uso terapêutico , Ansiedade/tratamento farmacológico , NADPH Oxidase 2/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Estresse Psicológico/psicologia , Animais , Protocolos de Quimioterapia Combinada Antineoplásica , Ansiedade/etiologia , Ansiedade/psicologia , Cisplatino , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Ifosfamida , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitomicina , NADPH Oxidase 2/metabolismo , NADPH Oxidases/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Estresse Psicológico/tratamento farmacológico
13.
Front Biosci (Landmark Ed) ; 24(5): 890-934, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30844720

RESUMO

Obesity has reached epidemic proportions and its prevalence is climbing. Obesity is characterized by hypertrophied adipocytes with a dysregulated adipokine secretion profile, increased recruitment of inflammatory cells, and impaired metabolic homeostasis that eventually results in the development of systemic insulin resistance, a phenotype of type 2 diabetes. Nitric oxide synthase (NOS) is an enzyme that converts L-arginine to nitric oxide (NO), which functions to maintain vascular and adipocyte homeostasis. Arginase is a ureohydrolase enzyme that competes with NOS for L-arginine. Arginase activity/expression is upregulated in obesity, which results in diminished bioavailability of NO, impairing both adipocyte and vascular endothelial cell function. Given the emerging role of NO in the regulation of adipocyte physiology and metabolic capacity, this review explores the interplay between arginase and NO, and their effect on the development of metabolic disorders, cardiovascular diseases, and mitochondrial dysfunction in obesity. A comprehensive understanding of the mechanisms involved in the development of obesity-induced metabolic and vascular dysfunction is necessary for the identification of more effective and tailored therapeutic avenues for their prevention and treatment.


Assuntos
Arginase/metabolismo , Doenças Metabólicas/metabolismo , Óxido Nítrico/metabolismo , Obesidade/metabolismo , Doenças Vasculares/metabolismo , Adipogenia , Adipocinas/metabolismo , Adiponectina/metabolismo , Tecido Adiposo/metabolismo , Proteína 2 Semelhante a Angiopoietina , Proteínas Semelhantes a Angiopoietina/metabolismo , Animais , Senescência Celular , Citocinas/metabolismo , Estresse do Retículo Endoplasmático , Proteínas Ligadas por GPI/metabolismo , Glucose/metabolismo , Humanos , Inflamação , Insulina/metabolismo , Lectinas/metabolismo , Leptina/metabolismo , Metabolismo dos Lipídeos , Lipocalina-2/metabolismo , Camundongos , Mitocôndrias/patologia , Nicotinamida Fosforribosiltransferase/metabolismo , Ratos , Resistina/metabolismo , Proteínas Plasmáticas de Ligação ao Retinol/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
14.
Int J Mol Sci ; 20(6)2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30909461

RESUMO

Visceral adipose tissue (VAT) inflammation and metabolic dysregulation are key components of obesity-induced metabolic disease. Upregulated arginase, a ureahydrolase enzyme with two isoforms (A1-cytosolic and A2-mitochondrial), is implicated in pathologies associated with obesity and diabetes. This study examined A2 involvement in obesity-associated metabolic and vascular disorders. WT and globally deleted A2(-/-) or A1(+/-) mice were fed either a high fat/high sucrose (HFHS) diet or normal diet (ND) for 16 weeks. Increases in body and VAT weight of HFHS-fed WT mice were abrogated in A2-/-, but not A1+/-, mice. Additionally, A2-/- HFHS-fed mice exhibited higher energy expenditure, lower blood glucose, and insulin levels compared to WT HFHS mice. VAT and adipocytes from WT HFHS fed mice showed greater A2 expression and adipocyte size and reduced expression of PGC-1α, PPAR-γ, and adiponectin. A2 deletion blunted these effects, increased levels of active AMPK-α, and upregulated genes involved in fatty acid metabolism. A2 deletion prevented HFHS-induced VAT collagen deposition and inflammation, which are involved in adipocyte metabolic dysfunction. Endothelium-dependent vasorelaxation, impaired by HFHS diet, was significantly preserved in A2-/- mice, but more prominently maintained in A1+/- mice. In summary, A2 is critically involved in HFHS-induced VAT inflammation and metabolic dysfunction.


Assuntos
Tecido Adiposo/metabolismo , Arginase/metabolismo , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético , Ácidos Graxos/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Adipócitos/metabolismo , Adipócitos/patologia , Tecido Adiposo/patologia , Animais , Arginase/genética , Biomarcadores , Modelos Animais de Doenças , Fibrose , Deleção de Genes , Hipertrofia , Camundongos , Obesidade/patologia , Oxirredução , Estresse Oxidativo , Consumo de Oxigênio , Sacarose/metabolismo
15.
Kidney Int ; 95(6): 1359-1372, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30905471

RESUMO

In mice, the initial stage of nephrotoxic serum-induced nephritis (NTN) mimics antibody-mediated human glomerulonephritis. Local immune deposits generate tumor necrosis factor (TNF), which activates pro-inflammatory pathways in glomerular endothelial cells (GECs) and podocytes. Because TNF receptors mediate antibacterial defense, existing anti-TNF therapies can promote infection; however, we have previously demonstrated that different functional domains of TNF may have opposing effects. The TIP peptide mimics the lectin-like domain of TNF, and has been shown to blunt inflammation in acute lung injury without impairing TNF receptor-mediated antibacterial activity. We evaluated the impact of TIP peptide in NTN. Intraperitoneal administration of TIP peptide reduced inflammation, proteinuria, and blood urea nitrogen. The protective effect was blocked by the cyclooxygenase inhibitor indomethacin, indicating involvement of prostaglandins. Targeted glomerular delivery of TIP peptide improved pathology in moderate NTN and reduced mortality in severe NTN, indicating a local protective effect. We show that TIP peptide activates the epithelial sodium channel(ENaC), which is expressed by GEC, upon binding to the channel's α subunit. In vitro, TNF treatment of GEC activated pro-inflammatory pathways and decreased the generation of prostaglandin E2 and nitric oxide, which promote recovery from NTN. TIP peptide counteracted these effects. Despite the capacity of TIP peptide to activate ENaC, it did not increase mean arterial blood pressure in mice. In the later autologous phase of NTN, TIP peptide blunted the infiltration of Th17 cells. By countering the deleterious effects of TNF through direct actions in GEC, TIP peptide could provide a novel strategy to treat glomerular inflammation.


Assuntos
Canais Epiteliais de Sódio/metabolismo , Glomerulonefrite/tratamento farmacológico , Glomérulos Renais/efeitos dos fármacos , Peptídeos Cíclicos/administração & dosagem , Proteinúria/tratamento farmacológico , Animais , Nitrogênio da Ureia Sanguínea , Linhagem Celular , Dinoprostona/metabolismo , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Feminino , Glomerulonefrite/sangue , Glomerulonefrite/imunologia , Glomerulonefrite/patologia , Humanos , Injeções Intraperitoneais , Glomérulos Renais/citologia , Glomérulos Renais/patologia , Camundongos , Óxido Nítrico/metabolismo , Técnicas de Patch-Clamp , Cultura Primária de Células , Proteinúria/sangue , Proteinúria/imunologia , Proteinúria/patologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Células Th17/efeitos dos fármacos , Células Th17/imunologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismo
16.
Indian J Ophthalmol ; 66(10): 1395-1400, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30249822

RESUMO

PURPOSE: To report mortality of patients who were eligible for enrollment in the Collaborative Ocular Melanoma Study (COMS) clinical trials of medium-sized choroidal melanoma or large-sized choroidal melanoma but chose to defer treatment or receive no melanoma treatment. DESIGN: Prospective nonrandomized multicenter cohort study as an adjunct to COMS randomized clinical trials. METHODS: Patient follow-up procedures included examinations, correspondence, telephone contacts, and National Death Index searches. Primary outcome was patient death measured by all-cause mortality. Secondary outcomes were melanoma treatment and melanoma metastasis. RESULTS: Of 77 patients eligible for COMS clinical trials who chose to defer or receive no melanoma treatment, 61 were appropriate candidates and 45 (74%) enrolled in the natural history study (NHS). In all, 42 patients (42 eyes) had medium melanoma, and the median follow-up was 5.3 years (range, 4-10.7 years). In all, 22 patients (52%) had subsequent melanoma treatment, and 20 (48%) had no melanoma treatment. For the 42 patients, Kaplan-Meier estimate of 5-year mortality was approximately 30% [95% confidence interval (CI), 18%-47%]. For COMS medium melanoma trial, 5-year mortality was 18% (95% CI, 16%-20%), not statistically significantly different from the NHS patients. After adjusting for differences in age and longest basal diameter, the 5-year risk of death for NHS patients versus COMS trial patients was 1.54 (95% CI, 0.93-2.56). Three patients had large melanoma. Melanoma metastasis was confirmed or suspected in 8 (42%) of 19 deaths. CONCLUSION: Greater mortality and higher risk of death for NHS patients are probative but not conclusive evidence of a beneficial, life-extending effect of medium melanoma treatment.


Assuntos
Neoplasias da Coroide/mortalidade , Melanoma/mortalidade , Suspensão de Tratamento , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Coroide/patologia , Neoplasias da Coroide/terapia , Enucleação Ocular , Feminino , Seguimentos , Humanos , Masculino , Melanoma/patologia , Melanoma/terapia , Pessoa de Meia-Idade , Estudos Prospectivos , Taxa de Sobrevida
17.
Afr J Prim Health Care Fam Med ; 10(1): e1-e10, 2018 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-29781691

RESUMO

BACKGROUND: There exists a major disparity in access to specialist care between patients in urban and rural areas. Specialists are a scarce resource and are concentrated in urban areas. Specialist outreach attempts to fill the gap in service provision for patients situated remotely. While there is international evidence that multifaceted specialist outreach has achieved varying levels of success, factors that influence the effectiveness of outreach have not yet been fully elucidated in South Africa. AIM: This study attempts to uncover some of the factors that enable good multifaceted specialist outreach. SETTING: The study was conducted in hospitals in western KwaZulu-Natal province. This health area is served by a tertiary hospital and 20 peripheral hospitals; three of these are regional level and the majority are district level hospitals. Specialist outreach emanates from the tertiary hospital. METHODS: Specialists providing outreach services from the tertiary hospital and medical officers at seven receiving hospitals were interviewed to explore perceptions regarding factors that might enable successful specialist outreach. Framework analysis on the transcribed interviews was carried out using NVivo version 11. RESULTS: A major positive finding concerns the relationships formed between outreach specialists and doctors at the recipient hospitals. The management of the programme with respect to structure, dependability, data management, transport provision, communication technology and public health systems was also seen as beneficial in specialist outreach. CONCLUSION: Specialist outreach plays an essential role in providing equality in health care. To enable effectiveness, it is important to make full use of the multifaceted nature of this intervention.


Assuntos
Relações Comunidade-Instituição , Acessibilidade aos Serviços de Saúde/organização & administração , Área Carente de Assistência Médica , Atenção Primária à Saúde/organização & administração , Serviços de Saúde Rural/organização & administração , Especialização , Adulto , Atitude do Pessoal de Saúde , Feminino , Disparidades em Assistência à Saúde , Humanos , Relações Interprofissionais , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa , População Rural , África do Sul
18.
J Med Imaging (Bellingham) ; 4(3): 035504, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28983495

RESUMO

Our goal was to ascertain how fatigue affects performance in reading computed tomography (CT) examinations of patients with multiple injuries. CT images with multiple fractures from a previous study of satisfaction of search (SOS) were read by radiologists after a day of clinical work. Performance in this study with fatigued readers was compared to a previous study in which readers were not fatigued. Detection accuracy for obvious injuries was not affected by fatigue, but accuracy for subtle fractures was reduced ([Formula: see text]). An SOS effect on decision thresholds was evident mirroring recent studies. Without fatigue, readers spent more time interpreting and reporting findings as the number of the injuries increased. When fatigued, readers did not increase reading time as fracture number increased. Without fractures, reading time for not-fatigued and fatigued readers was the same ([Formula: see text]) but was significant ([Formula: see text]) with an added subtle fracture. The difference increased with a major injury ([Formula: see text]) and increased further with both a major injury and subtle fracture ([Formula: see text]). Fatigue and multiple abnormalities have independent effects on detection performance but do interact in determining search time.

19.
Cardiovasc Res ; 113(13): 1664-1676, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29048462

RESUMO

AIMS: Elevation of arginase activity has been linked to vascular dysfunction in diabetes and hypertension by a mechanism involving decreased nitric oxide (NO) bioavailability due to L-arginine depletion. Excessive arginase activity also can drive L-arginine metabolism towards the production of ornithine, polyamines, and proline, promoting proliferation of vascular smooth muscle cells and collagen formation, leading to perivascular fibrosis. We hypothesized that there is a specific involvement of arginase 1 expression within the vascular endothelial cells in this pathology. METHODS AND RESULTS: To test this proposition, we used models of type 2 diabetes and metabolic syndrome. Studies were performed using wild type (WT), endothelial-specific arginase 1 knockout (EC-A1-/-) and littermate controls(A1con) mice fed high fat-high sucrose (HFHS) or normal diet (ND) for 6 months and isolated vessels exposed to palmitate-high glucose (PA/HG) media. Some WT mice or isolated vessels were treated with an arginase inhibitor, ABH [2-(S)-amino-6-boronohexanoic acid. In WT mice, the HFHS diet promoted increases in body weight, fasting blood glucose, and post-prandial insulin levels along with arterial stiffening and fibrosis, elevated blood pressure, decreased plasma levels of L-arginine, and elevated L-ornithine. The HFHS diet or PA/HG treatment also induced increases in vascular arginase activity along with oxidative stress, reduced vascular NO levels, and impaired endothelial-dependent vasorelaxation. All of these effects except obesity and hypercholesterolemia were prevented or significantly reduced by endothelial-specific deletion of arginase 1 or ABH treatment. CONCLUSION: Vascular dysfunctions in diet-induced obesity are prevented by deletion of arginase 1 in vascular endothelial cells or arginase inhibition. These findings indicate that upregulation of arginase 1 expression/activity in vascular endothelial cells has an integral role in diet-induced cardiovascular dysfunction and metabolic syndrome.


Assuntos
Arginase/metabolismo , Diabetes Mellitus Experimental/enzimologia , Diabetes Mellitus Tipo 2/enzimologia , Endotélio Vascular/enzimologia , Síndrome Metabólica/enzimologia , Obesidade/enzimologia , Doenças Vasculares/enzimologia , Rigidez Vascular , Animais , Arginase/antagonistas & inibidores , Arginase/genética , Arginina/sangue , Glicemia/metabolismo , Pressão Sanguínea , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/prevenção & controle , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/prevenção & controle , Dieta Hiperlipídica , Sacarose Alimentar , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/patologia , Endotélio Vascular/fisiopatologia , Inibidores Enzimáticos/farmacologia , Fibrose , Predisposição Genética para Doença , Insulina/sangue , Masculino , Síndrome Metabólica/genética , Síndrome Metabólica/fisiopatologia , Síndrome Metabólica/prevenção & controle , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/metabolismo , Obesidade/tratamento farmacológico , Obesidade/genética , Obesidade/fisiopatologia , Ornitina/sangue , Estresse Oxidativo , Fenótipo , Transdução de Sinais , Doenças Vasculares/genética , Doenças Vasculares/fisiopatologia , Doenças Vasculares/prevenção & controle , Rigidez Vascular/efeitos dos fármacos , Vasodilatação
20.
Antioxidants (Basel) ; 6(2)2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28617308

RESUMO

Increases in reactive oxygen species (ROS) and decreases in nitric oxide (NO) have been linked to vascular dysfunction during diabetic retinopathy (DR). Diabetes can reduce NO by increasing ROS and by increasing activity of arginase, which competes with nitric oxide synthase (NOS) for their commons substrate l-arginine. Increased ROS and decreased NO can cause premature endothelial cell (EC) senescence leading to defective vascular repair. We have previously demonstrated the involvement of NADPH oxidase 2 (NOX2)-derived ROS, decreased NO and overactive arginase in DR. Here, we investigated their impact on diabetes-induced EC senescence. Studies using diabetic mice and retinal ECs treated with high glucose or H2O2 showed that increases in ROS formation, elevated arginase expression and activity, and decreased NO formation led to premature EC senescence. NOX2 blockade or arginase inhibition prevented these effects. EC senescence was also increased by inhibition of NOS activity and this was prevented by treatment with a NO donor. These results indicate that diabetes/high glucose-induced activation of arginase and decreases in NO bioavailability accelerate EC senescence. NOX2-generated ROS contribute importantly to this process. Blockade of NOX2 or arginase represents a strategy to prevent diabetes-induced premature EC senescence by preserving NO bioavailability.

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