Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Nat Immunol ; 20(9): 1186-1195, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31384058

RESUMO

Macrophages are activated during microbial infection to coordinate inflammatory responses and host defense. Here we find that in macrophages activated by bacterial lipopolysaccharide (LPS), mitochondrial glycerol 3-phosphate dehydrogenase (GPD2) regulates glucose oxidation to drive inflammatory responses. GPD2, a component of the glycerol phosphate shuttle, boosts glucose oxidation to fuel the production of acetyl coenzyme A, acetylation of histones and induction of genes encoding inflammatory mediators. While acute exposure to LPS drives macrophage activation, prolonged exposure to LPS triggers tolerance to LPS, where macrophages induce immunosuppression to limit the detrimental effects of sustained inflammation. The shift in the inflammatory response is modulated by GPD2, which coordinates a shutdown of oxidative metabolism; this limits the availability of acetyl coenzyme A for histone acetylation at genes encoding inflammatory mediators and thus contributes to the suppression of inflammatory responses. Therefore, GPD2 and the glycerol phosphate shuttle integrate the extent of microbial stimulation with glucose oxidation to balance the beneficial and detrimental effects of the inflammatory response.


Assuntos
Glucose/metabolismo , Glicerolfosfato Desidrogenase/metabolismo , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Acetilcoenzima A/biossíntese , Acetilação , Animais , Feminino , Histonas/metabolismo , Inflamação/patologia , Lipopolissacarídeos , Macrófagos/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxirredução
3.
Nature ; 2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39443794

RESUMO

The ability of stony corals to thrive in the oligotrophic (low-nutrient, low-productivity) surface waters of the tropical ocean is commonly attributed to their symbiotic relationship with photosynthetic dinoflagellates1,2. The evolutionary history of this symbiosis might clarify its organismal and environmental roles3, but its prevalence through time, and across taxa, morphologies and oceanic settings, is currently unclear4-6. Here we report measurements of the nitrogen isotope (15N/14N) ratio of coral-bound organic matter (CB-δ15N) in samples from Mid-Devonian reefs (Givetian, around 385 million years ago), which represent a constraint on the evolution of coral photosymbiosis. Colonial tabulate and fasciculate (dendroid) rugose corals have low CB-δ15N values (2.51 ± 0.97‰) in comparison with co-occurring solitary and (pseudo)colonial (cerioid or phaceloid) rugose corals (5.52 ± 1.63‰). The average of the isotopic difference per deposit (3.01 ± 0.58‰) is statistically indistinguishable from that observed between modern symbiont-barren and symbiont-bearing corals (3.38 ± 1.05‰). On the basis of this evidence, we infer that Mid-Devonian tabulate and some fasciculate (dendroid) rugose corals hosted active photosymbionts, while solitary and some (pseudo)colonial (cerioid or phaceloid) rugose corals did not. The low CB-δ15N values of the Devonian tabulate and fasciculate rugose corals relative to the modern range suggest that Mid-Devonian reefs formed in biogeochemical regimes analogous to the modern oligotrophic subtropical gyres. Widespread oligotrophy during the Devonian may have promoted coral photosymbiosis, the occurrence of which may explain why Devonian reefs were the most productive reef ecosystems of the Phanerozoic.

4.
Immunity ; 52(1): 167-182.e7, 2020 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-31883839

RESUMO

Multiple sclerosis (MS) is a demyelinating, autoimmune disease of the central nervous system. While work has focused on myelin and axon loss in MS, less is known about mechanisms underlying synaptic changes. Using postmortem human MS tissue, a preclinical nonhuman primate model of MS, and two rodent models of demyelinating disease, we investigated synapse changes in the visual system. Similar to other neurodegenerative diseases, microglial synaptic engulfment and profound synapse loss were observed. In mice, synapse loss occurred independently of local demyelination and neuronal degeneration but coincided with gliosis and increased complement component C3, but not C1q, at synapses. Viral overexpression of the complement inhibitor Crry at C3-bound synapses decreased microglial engulfment of synapses and protected visual function. These results indicate that microglia eliminate synapses through the alternative complement cascade in demyelinating disease and identify a strategy to prevent synapse loss that may be broadly applicable to other neurodegenerative diseases. VIDEO ABSTRACT.


Assuntos
Complemento C3/imunologia , Encefalomielite Autoimune Experimental/patologia , Microglia/patologia , Esclerose Múltipla/patologia , Sinapses/patologia , Tálamo/patologia , Idoso , Idoso de 80 Anos ou mais , Animais , Callithrix , Linhagem Celular Tumoral , Complemento C3/antagonistas & inibidores , Modelos Animais de Doenças , Feminino , Gliose/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores de Complemento 3b/metabolismo
5.
Nature ; 618(7963): 87-93, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37259003

RESUMO

Technologically critical rare-earth elements are notoriously difficult to separate, owing to their subtle differences in ionic radius and coordination number1-3. The natural lanthanide-binding protein lanmodulin (LanM)4,5 is a sustainable alternative to conventional solvent-extraction-based separation6. Here we characterize a new LanM, from Hansschlegelia quercus (Hans-LanM), with an oligomeric state sensitive to rare-earth ionic radius, the lanthanum(III)-induced dimer being >100-fold tighter than the dysprosium(III)-induced dimer. X-ray crystal structures illustrate how picometre-scale differences in radius between lanthanum(III) and dysprosium(III) are propagated to Hans-LanM's quaternary structure through a carboxylate shift that rearranges a second-sphere hydrogen-bonding network. Comparison to the prototypal LanM from Methylorubrum extorquens reveals distinct metal coordination strategies, rationalizing Hans-LanM's greater selectivity within the rare-earth elements. Finally, structure-guided mutagenesis of a key residue at the Hans-LanM dimer interface modulates dimerization in solution and enables single-stage, column-based separation of a neodymium(III)/dysprosium(III) mixture to >98% individual element purities. This work showcases the natural diversity of selective lanthanide recognition motifs, and it reveals rare-earth-sensitive dimerization as a biological principle by which to tune the performance of biomolecule-based separation processes.


Assuntos
Proteínas de Bactérias , Elementos da Série dos Lantanídeos , Lantânio , Multimerização Proteica , Disprósio/química , Disprósio/isolamento & purificação , Íons/química , Elementos da Série dos Lantanídeos/química , Elementos da Série dos Lantanídeos/isolamento & purificação , Lantânio/química , Neodímio/química , Neodímio/isolamento & purificação , Methylocystaceae , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Estrutura Quaternária de Proteína
6.
Nat Immunol ; 17(8): 946-55, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27348411

RESUMO

Studies of individual T cell antigen receptors (TCRs) have shed some light on structural features that underlie self-reactivity. However, the general rules that can be used to predict whether TCRs are self-reactive have not been fully elucidated. Here we found that the interfacial hydrophobicity of amino acids at positions 6 and 7 of the complementarity-determining region CDR3ß robustly promoted the development of self-reactive TCRs. This property was found irrespective of the member of the ß-chain variable region (Vß) family present in the TCR or the length of the CDR3ß. An index based on these findings distinguished Vß2(+), Vß6(+) and Vß8.2(+) regulatory T cells from conventional T cells and also distinguished CD4(+) T cells selected by the major histocompatibility complex (MHC) class II molecule I-A(g7) (associated with the development of type 1 diabetes in NOD mice) from those selected by a non-autoimmunity-promoting MHC class II molecule I-A(b). Our results provide a means for distinguishing normal T cell repertoires versus autoimmunity-prone T cell repertoires.


Assuntos
Autoimunidade , Regiões Determinantes de Complementaridade/genética , Diabetes Mellitus Tipo 1/imunologia , Subpopulações de Linfócitos T/fisiologia , Linfócitos T Reguladores/fisiologia , Animais , Autoantígenos/imunologia , Autoantígenos/metabolismo , Diferenciação Celular , Tolerância Central , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Antígenos de Histocompatibilidade Classe II/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout
7.
Rapid Commun Mass Spectrom ; 38(1): e9650, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38073197

RESUMO

The analysis of the nitrogen (N) isotopic composition of organic matter bound to fossil biomineral structures (BB-δ15 N) using the oxidation-denitrifier (O-D) method provides a novel tool to study past changes in N cycling processes. METHODS: We report a set of methodological improvements to the O-D method, including (a) a method for sealing the reaction vials in which the oxidation of organic N to NO3 - takes place, (b) a recipe for bypassing the pH adjustment step before the bacterial conversion of NO3 - to N2 O, and (c) a method for storing recrystallized dipotassium peroxodisulfate (K2 S2 O8 ) under Ar atmosphere. RESULTS: The new sealing method eliminates the occasional contamination and vial breakage that occurred previously while increasing sample throughput. The protocol for bypassing pH adjustment does not affect BB-δ15 N, and it significantly reduces the processing time. Storage of K2 S2 O8 reagent under Ar atmosphere produces stable oxidation blanks over more than 3.5 years. We report analytical blanks, accuracy, and precision for this methodology from eight users over the course of ~3.5 years of analyses at the Max Planck Institute for Chemistry. Our method produces analytical blanks characterized by low N content (0.30 ± 0.13 nmol N, 1σ, n = 195) and stable δ15 N (-2.20 ± 3.13‰, n = 195). The analysis of reference amino acid standards USGS 40 and USGS 65 indicates an overall accuracy of -0.23 ± 0.35‰ (1σ, n = 891). The analysis of in-house fossil standards gives similar analytical precision (1σ) across a range of BB-δ15 N values and biominerals: zooxanthellate coral standard PO-1 (6.08 ± 0.21‰, n = 267), azooxanthellate coral standard LO-1 (10.20 ± 0.28‰, n = 258), foraminifera standard MF-1 (5.92 ± 0.28‰, n = 243), and tooth enamel AG-Lox (4.06 ± 0.49‰, n = 78). CONCLUSIONS: The methodological improvements significantly increase sample throughput without compromising analytical precision or accuracy down to 1 nmol of N.

8.
Nat Chem Biol ; 12(11): 980-987, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27618190

RESUMO

CRISPR-Cas9 has emerged as a powerful technology that enables ready modification of the mammalian genome. The ability to modulate Cas9 activity can reduce off-target cleavage and facilitate precise genome engineering. Here we report the development of a Cas9 variant whose activity can be switched on and off in human cells with 4-hydroxytamoxifen (4-HT) by fusing the Cas9 enzyme with the hormone-binding domain of the estrogen receptor (ERT2). The final optimized variant, termed iCas, showed low endonuclease activity without 4-HT but high editing efficiency at multiple loci with the chemical. We also tuned the duration and concentration of 4-HT treatment to reduce off-target genome modification. Additionally, we benchmarked iCas against other chemical-inducible methods and found that it had the fastest on rate and that its activity could be toggled on and off repeatedly. Collectively, these results highlight the utility of iCas for rapid and reversible control of genome-editing function.


Assuntos
Sistemas CRISPR-Cas/efeitos dos fármacos , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Tamoxifeno/análogos & derivados , Células HEK293 , Humanos , Tamoxifeno/química , Tamoxifeno/farmacologia
9.
Gut ; 66(6): 1060-1073, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-26953272

RESUMO

OBJECTIVE: Patients with Niemann-Pick disease type C1 (NPC1), a lysosomal lipid storage disorder that causes neurodegeneration and liver damage, can present with IBD, but neither the significance nor the functional mechanism of this association is clear. We studied bacterial handling and antibacterial autophagy in patients with NPC1. DESIGN: We characterised intestinal inflammation in 14 patients with NPC1 who developed IBD. We investigated bacterial handling and cytokine production of NPC1 monocytes or macrophages in vitro and compared NPC1-associated functional defects to those caused by IBD-associated nucleotide-binding oligomerization domain-containing protein 2 (NOD2) variants or mutations in X-linked inhibitor of apoptosis (XIAP). RESULTS: Patients with the lysosomal lipid storage disorder NPC1 have increased susceptibility to early-onset fistulising colitis with granuloma formation, reminiscent of Crohn's disease (CD). Mutations in NPC1 cause impaired autophagy due to defective autophagosome function that abolishes NOD2-mediated bacterial handling in vitro similar to variants in NOD2 or XIAP deficiency. In contrast to genetic NOD2 and XIAP variants, NPC1 mutations do not impair NOD2-receptor-interacting kinase 2 (RIPK2)-XIAP-dependent cytokine production. Pharmacological activation of autophagy can rescue bacterial clearance in macrophages in vitro by increasing the autophagic flux and bypassing defects in NPC1. CONCLUSIONS: NPC1 confers increased risk of early-onset severe CD. Our data support the concept that genetic defects at different checkpoints of selective autophagy cause a shared outcome of CD-like immunopathology linking monogenic and polygenic forms of IBD. Muramyl dipeptide-driven cytokine responses and antibacterial autophagy induction are parallel and independent signalling cascades downstream of the NOD2-RIPK2-XIAP complex.


Assuntos
Acetilmuramil-Alanil-Isoglutamina/metabolismo , Autofagia/genética , Doença de Crohn/genética , Granuloma/genética , Macrófagos/efeitos dos fármacos , Doença de Niemann-Pick Tipo C/genética , Doença de Niemann-Pick Tipo C/fisiopatologia , Proteína Adaptadora de Sinalização NOD2/genética , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/genética , Acetilmuramil-Alanil-Isoglutamina/farmacologia , Adolescente , Adulto , Antibacterianos/farmacologia , Autofagia/efeitos dos fármacos , Bactérias , Células Cultivadas , Criança , Pré-Escolar , Clorpromazina/farmacologia , Doença de Crohn/complicações , Doença de Crohn/patologia , Antagonistas de Dopamina/farmacologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/genética , Gentamicinas/farmacologia , Granuloma/patologia , Humanos , Imidazóis/farmacologia , Leucócitos Mononucleares , Lisossomos , Macrófagos/fisiologia , Masculino , Mutação , Doença de Niemann-Pick Tipo C/complicações , Proteína Adaptadora de Sinalização NOD2/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Piridazinas/farmacologia , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/antagonistas & inibidores , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/deficiência , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo , Adulto Jovem
10.
Gut ; 64(2): 312-21, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24837171

RESUMO

OBJECTIVE: Following chronic liver injury or when hepatocyte proliferation is impaired, ductular reactions containing hepatic progenitor cells (HPCs) appear in the periportal regions and can regenerate the liver parenchyma. HPCs exist in a niche composed of myofibroblasts, macrophages and laminin matrix. Galectin-3 (Gal-3) is a ß-galactoside-binding lectin that binds to laminin and is expressed in injured liver in mice and humans. DESIGN: We examined the role of Gal-3 in HPC activation. HPC activation was studied following dietary induced hepatocellular (choline-deficient ethionine-supplemented diet) and biliary (3,5-diethoxycarbonyl-1,4-dihydrocollidine supplemented diet) injury in wild type and Gal-3(-/-) mice. RESULTS: HPC proliferation was significantly reduced in Gal-3(-/-) mice. Gal-3(-/-) mice failed to form a HPC niche, with reduced laminin formation. HPCs isolated from wild type mice secrete Gal-3 which enhanced adhesion and proliferation of HPCs on laminin in an undifferentiated form. These effects were attenuated in Gal3(-/-) HPCs and in wild type HPCs treated with the Gal-3 inhibitor lactose. Gal-3(-/-) HPCs in vitro showed increased hepatocyte function and prematurely upregulated both biliary and hepatocyte differentiation markers and regulated cell cycle genes leading to arrest in G0/G1. CONCLUSIONS: We conclude that Gal-3 is required for the undifferentiated expansion of HPCs in their niche in injured liver.


Assuntos
Galectina 3/fisiologia , Fígado/lesões , Células-Tronco/patologia , Animais , Adesão Celular/fisiologia , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Dieta/efeitos adversos , Galectina 3/biossíntese , Galectina 3/deficiência , Hepatócitos/fisiologia , Humanos , Laminina/metabolismo , Fígado/metabolismo , Fígado/patologia , Regeneração Hepática/fisiologia , Macrófagos/metabolismo , Macrófagos/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nicho de Células-Tronco/fisiologia , Células-Tronco/metabolismo , Células-Tronco/fisiologia , Regulação para Cima
11.
Nat Biotechnol ; 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38195986

RESUMO

To survey cancer-related mutations in human pluripotent stem cells and their derivatives, we analyzed >2,200 transcriptomes from 146 independent lines in the NCBI's Sequence Read Archive. Twenty-two per cent of samples had at least one cancer-related mutation; of these, 64% had TP53 mutations, which conferred a pronounced selective advantage, perturbed target gene expression and altered cellular differentiation. These findings underscore the need for robust surveillance of cancer-related mutations in pluripotent cells, especially in clinical applications.

12.
Nat Commun ; 15(1): 2497, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38509062

RESUMO

Microglia play a pivotal role in neurodegenerative disease pathogenesis, but the mechanisms underlying microglia dysfunction and toxicity remain to be elucidated. To investigate the effect of neurodegenerative disease-linked genes on the intrinsic properties of microglia, we studied microglia-like cells derived from human induced pluripotent stem cells (iPSCs), termed iMGs, harboring mutations in profilin-1 (PFN1) that are causative for amyotrophic lateral sclerosis (ALS). ALS-PFN1 iMGs exhibited evidence of lipid dysmetabolism, autophagy dysregulation and deficient phagocytosis, a canonical microglia function. Mutant PFN1 also displayed enhanced binding affinity for PI3P, a critical signaling molecule involved in autophagic and endocytic processing. Our cumulative data implicate a gain-of-toxic function for mutant PFN1 within the autophagic and endo-lysosomal pathways, as administration of rapamycin rescued phagocytic dysfunction in ALS-PFN1 iMGs. These outcomes demonstrate the utility of iMGs for neurodegenerative disease research and implicate microglial vesicular degradation pathways in the pathogenesis of these disorders.


Assuntos
Esclerose Lateral Amiotrófica , Células-Tronco Pluripotentes Induzidas , Doenças Neurodegenerativas , Humanos , Esclerose Lateral Amiotrófica/metabolismo , Microglia/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Profilinas/metabolismo , Mutação
13.
Cells ; 12(5)2023 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-36899827

RESUMO

An acute inflammatory response following arterial surgery for atherosclerosis, such as balloon angioplasty, stenting, and surgical bypass, is an important driver of neointimal hyperplasia after arterial injury, which leads to recurrent ischemia. However, a comprehensive understanding of the dynamics of the inflammatory infiltrate in the remodeling artery is difficult to attain due to the shortcomings of conventional methods such as immunofluorescence. We developed a 15-parameter flow cytometry method to quantitate leukocytes and 13 leukocyte subtypes in murine arteries at 4 time points after femoral artery wire injury. Live leukocyte numbers peaked at 7 days, which preceded the peak neointimal hyperplasia lesion at 28 days. Neutrophils were the most abundant early infiltrate, followed by monocytes and macrophages. Eosinophils were elevated after 1 day, while natural killer and dendritic cells gradually infiltrated over the first 7 days; all decreased between 7 and 14 days. Lymphocytes began accumulating at 3 days and peaked at 7 days. Immunofluorescence of arterial sections demonstrated similar temporal trends of CD45+ and F4/80+ cells. This method allows for the simultaneous quantitation of multiple leukocyte subtypes from small tissue samples of injured murine arteries and identifies the CD64+Tim4+ macrophage phenotype as being potentially important in the first 7 days post-injury.


Assuntos
Artéria Femoral , Macrófagos , Camundongos , Animais , Hiperplasia , Citometria de Fluxo , Monócitos , Neointima
14.
bioRxiv ; 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37398081

RESUMO

Microglia play a pivotal role in neurodegenerative disease pathogenesis, but the mechanisms underlying microglia dysfunction and toxicity remain to be fully elucidated. To investigate the effect of neurodegenerative disease-linked genes on the intrinsic properties of microglia, we studied microglia-like cells derived from human induced pluripotent stem cells (iPSCs), termed iMGs, harboring mutations in profilin-1 (PFN1) that are causative for amyotrophic lateral sclerosis (ALS). ALS-PFN1 iMGs exhibited lipid dysmetabolism and deficits in phagocytosis, a critical microglia function. Our cumulative data implicate an effect of ALS-linked PFN1 on the autophagy pathway, including enhanced binding of mutant PFN1 to the autophagy signaling molecule PI3P, as an underlying cause of defective phagocytosis in ALS-PFN1 iMGs. Indeed, phagocytic processing was restored in ALS-PFN1 iMGs with Rapamycin, an inducer of autophagic flux. These outcomes demonstrate the utility of iMGs for neurodegenerative disease research and highlight microglia vesicular degradation pathways as potential therapeutic targets for these disorders.

15.
bioRxiv ; 2023 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-37961405

RESUMO

Short-term preoperative methionine restriction (MetR) shows promise as a translatable strategy to modulate the body's response to surgical injury. Its application, however, to improve post-interventional vascular remodeling remains underexplored. Here, we find that MetR protects from arterial intimal hyperplasia in a focal stenosis model and adverse vascular remodeling after vein graft surgery. RNA sequencing reveals that MetR enhances the brown adipose tissue phenotype in arterial perivascular adipose tissue (PVAT) and induces it in venous PVAT. Specifically, PPAR-α was highly upregulated in PVAT-adipocytes. Furthermore, MetR dampens the post-operative pro-inflammatory response to surgery in PVAT-macrophages in vivo and in vitro . This study shows for the first time that the detrimental effects of dysfunctional PVAT on vascular remodeling can be reversed by MetR, and identifies pathways involved in browning of PVAT. Furthermore, we demonstrate the potential of short-term pre-operative MetR as a simple intervention to ameliorate vascular remodeling after vascular surgery.

16.
Cell Rep ; 40(7): 111187, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35977507

RESUMO

Dietary protein restriction (PR) has rapid effects on metabolism including improved glucose and lipid homeostasis, via multiple mechanisms. Here, we investigate responses of fecal microbiome, hepatic transcriptome, and hepatic metabolome to six diets with protein from 18% to 0% of energy in mice. PR alters fecal microbial composition, but metabolic effects are not transferable via fecal transplantation. Hepatic transcriptome and metabolome are significantly altered in diets with lower than 10% energy from protein. Changes upon PR correlate with calorie restriction but with a larger magnitude and specific changes in amino acid (AA) metabolism. PR increases steady-state aspartate, serine, and glutamate and decreases glucose and gluconeogenic intermediates. 13C6 glucose and glycerol tracing reveal increased fractional enrichment in aspartate, serine, and glutamate. Changes remain intact in hepatic ATF4 knockout mice. Together, this demonstrates an ATF4-independent shift in gluconeogenic substrate utilization toward specific AAs, with compensation from glycerol to promote a protein-sparing response.


Assuntos
Glucose , Glicerol , Animais , Ácido Aspártico/metabolismo , Proteínas Alimentares/metabolismo , Gluconeogênese , Glucose/metabolismo , Ácido Glutâmico/metabolismo , Glicerol/metabolismo , Fígado/metabolismo , Camundongos , Serina/metabolismo
17.
Cell Metab ; 33(9): 1808-1819.e2, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34270927

RESUMO

Plant-based dietary patterns are associated with improved cardiometabolic health, but causal dietary components are unclear. Protein has been proposed to play a role, but the importance of protein quantity versus quality remains unknown. We investigated the contributions of total protein amount, amino acid (AA) composition, and plant versus animal source. Analysis of total protein and AA composition of food items and dietary patterns revealed differences between individual food items, but few differences between AA profiles of vegan versus omnivorous dietary patterns. Effects of protein quantity, but not quality, on cardiometabolic health markers were observed in mice using semi-purified diets with crystalline AAs in plant versus animal-based ratios and naturally sourced diets with whole-food ingredients. Our data show relatively little difference in protein quality between plant-based and omnivorous dietary patterns and that reduced total protein intake in plant-based dietary patterns may be a contributor to the benefits of plant-based diets.


Assuntos
Aminoácidos , Dieta Vegetariana , Animais , Dieta , Alimentos , Camundongos
18.
Nutrients ; 13(11)2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34836280

RESUMO

(1) Background: Vascular surgery operations are hampered by high failure rates and frequent occurrence of peri-operative cardiovascular complications. In pre-clinical studies, pre-operative restriction of proteins and/or calories (PCR) has been shown to limit ischemia-reperfusion damage, slow intimal hyperplasia, and improve metabolic fitness. However, whether these dietary regimens are feasible and safe in the vascular surgery patient population remains unknown. (2) Methods: We performed a randomized controlled trial in patients scheduled for any elective open vascular procedure. Participants were randomized in a 3:2 ratio to either four days of outpatient pre-operative PCR (30% calorie, 70% protein restriction) or their regular ad-libitum diet. Blood was drawn at baseline, pre-operative, and post-operative day 1 timepoints. A leukocyte subset flow cytometry panel was performed at these timepoints. Subcutaneous/perivascular adipose tissue was sampled and analyzed. Follow-up was one year post-op. (3) Results: 19 patients were enrolled, of whom 11 completed the study. No diet-related reasons for non-completion were reported, and there was no intervention group crossover. The PCR diet induced weight loss and BMI decrease without malnutrition. Insulin sensitivity was improved after four days of PCR (p = 0.05). Between diet groups, there were similar rates of re-intervention, wound infection, and cardiovascular complications. Leukocyte populations were maintained after four days of PCR. (4) Conclusions: Pre-operative PCR is safe and feasible in elective vascular surgery patients.


Assuntos
Restrição Calórica/métodos , Proteínas/administração & dosagem , Procedimentos Cirúrgicos Vasculares/métodos , Idoso , Citocinas , Dieta , Dietoterapia , Ingestão de Energia , Exercício Físico , Feminino , Glucose , Homeostase , Humanos , Imunidade , Masculino , Pessoa de Meia-Idade , Redução de Peso
19.
J Am Heart Assoc ; 9(22): e016391, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33146045

RESUMO

Background Failure rates after revascularization surgery remain high, both in vein grafts (VG) and arterial interventions. One promising approach to improve outcomes is endogenous upregulation of the gaseous transmitter-molecule hydrogen sulfide, via short-term dietary restriction. However, strict patient compliance stands as a potential translational barrier in the vascular surgery patient population. Here we present a new therapeutic approach, via a locally applicable gel containing the hydrogen sulfide releasing prodrug (GYY), to both mitigate graft failure and improve arterial remodeling. Methods and Results All experiments were performed on C57BL/6 (male, 12 weeks old) mice. VG surgery was performed by grafting a donor-mouse cava vein into the right common carotid artery of a recipient via an end-to-end anastomosis. In separate experiments arterial intimal hyperplasia was assayed via a right common carotid artery focal stenosis model. All mice were harvested at postoperative day 28 and artery/graft was processed for histology. Efficacy of hydrogen sulfide was first tested via GYY supplementation of drinking water either 1 week before VG surgery (pre-GYY) or starting immediately postoperatively (post-GYY). Pre-GYY mice had a 36.5% decrease in intimal/media+adventitia area ratio compared with controls. GYY in a 40% Pluronic gel (or vehicle) locally applied to the graft/artery had decreased intimal/media area ratios (right common carotid artery) and improved vessel diameters. GYY-geltreated VG had larger diameters at both postoperative days 14 and 28, and a 56.7% reduction in intimal/media+adventitia area ratios. Intimal vascular smooth muscle cell migration was decreased 30.6% after GYY gel treatment, which was reproduced in vitro. Conclusions Local gel-based treatment with the hydrogen sulfide-donor GYY stands as a translatable therapy to improve VG durability and arterial remodeling after injury.


Assuntos
Gasotransmissores/uso terapêutico , Sulfeto de Hidrogênio/uso terapêutico , Neointima/patologia , Neointima/prevenção & controle , Enxerto Vascular/efeitos adversos , Remodelação Vascular , Anastomose Cirúrgica , Animais , Artéria Carótida Primitiva/cirurgia , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neointima/etiologia , Veias Cavas/transplante
20.
Bone Res ; 8: 24, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32566365

RESUMO

The GP130 cytokine receptor subunit encoded by IL6ST is the shared receptor for ten cytokines of the IL-6 family. We describe a homozygous non-synonymous variant in IL6ST (p.R281Q) in a patient with craniosynostosis and retained deciduous teeth. We characterize the impact of the variant on cytokine signaling in vitro using transfected cell lines as well as primary patient-derived cells and support these findings using a mouse model with the corresponding genome-edited variant Il6st p.R279Q. We show that human GP130 p.R281Q is associated with selective loss of IL-11 signaling without affecting IL-6, IL-27, OSM, LIF, CT1, CLC, and CNTF signaling. In mice Il6st p.R279Q lowers litter size and causes facial synostosis and teeth abnormalities. The effect on IL-11 signaling caused by the GP130 variant shows incomplete penetrance but phenocopies aspects of IL11RA deficiency in humans and mice. Our data show that a genetic variant in a pleiotropic cytokine receptor can have remarkably selective defects.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA