Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 65
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Immunity ; 54(9): 2024-2041.e8, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34473957

RESUMO

Sepsis results in elevated adenosine in circulation. Extracellular adenosine triggers immunosuppressive signaling via the A2a receptor (A2aR). Sepsis survivors develop persistent immunosuppression with increased risk of recurrent infections. We utilized the cecal ligation and puncture (CLP) model of sepsis and subsequent infection to assess the role of adenosine in post-sepsis immune suppression. A2aR-deficient mice showed improved resistance to post-sepsis infections. Sepsis expanded a subset of CD39hi B cells and elevated extracellular adenosine, which was absent in mice lacking CD39-expressing B cells. Sepsis-surviving B cell-deficient mice were more resistant to secondary infections. Mechanistically, metabolic reprogramming of septic B cells increased production of ATP, which was converted into adenosine by CD39 on plasmablasts. Adenosine signaling via A2aR impaired macrophage bactericidal activity and enhanced interleukin-10 production. Septic individuals exhibited expanded CD39hi plasmablasts and adenosine accumulation. Our study reveals CD39hi plasmablasts and adenosine as important drivers of sepsis-induced immunosuppression with relevance in human disease.


Assuntos
Adenosina/imunologia , Antígenos CD/imunologia , Apirase/imunologia , Tolerância Imunológica/imunologia , Macrófagos/imunologia , Plasmócitos/imunologia , Sepse/imunologia , Adenosina/metabolismo , Animais , Antígenos CD/metabolismo , Apirase/metabolismo , Reprogramação Celular/imunologia , Macrófagos/metabolismo , Camundongos , Plasmócitos/metabolismo , Receptor A2A de Adenosina/imunologia , Receptor A2A de Adenosina/metabolismo , Sepse/metabolismo
2.
Mol Cell ; 81(4): 691-707.e6, 2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33382985

RESUMO

Aerobic glycolysis, or preferential fermentation of glucose-derived pyruvate to lactate despite available oxygen, is associated with proliferation across many organisms and conditions. To better understand that association, we examined the metabolic consequence of activating the pyruvate dehydrogenase complex (PDH) to increase pyruvate oxidation at the expense of fermentation. We find that increasing PDH activity impairs cell proliferation by reducing the NAD+/NADH ratio. This change in NAD+/NADH is caused by increased mitochondrial membrane potential that impairs mitochondrial electron transport and NAD+ regeneration. Uncoupling respiration from ATP synthesis or increasing ATP hydrolysis restores NAD+/NADH homeostasis and proliferation even when glucose oxidation is increased. These data suggest that when demand for NAD+ to support oxidation reactions exceeds the rate of ATP turnover in cells, NAD+ regeneration by mitochondrial respiration becomes constrained, promoting fermentation, despite available oxygen. This argues that cells engage in aerobic glycolysis when the demand for NAD+ is in excess of the demand for ATP.


Assuntos
Trifosfato de Adenosina/metabolismo , Glucose/metabolismo , Glicólise , NAD/metabolismo , Células A549 , Trifosfato de Adenosina/genética , Aerobiose , Glucose/genética , Células HeLa , Humanos , NAD/genética , Oxirredução
3.
Sensors (Basel) ; 23(13)2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37447792

RESUMO

Nowadays, the Internet of Things (IoT) concept plays a pivotal role in society and brings new capabilities to different industries. The number of IoT solutions in areas such as transportation and healthcare is increasing and new services are under development. In the last decade, society has experienced a drastic increase in IoT connections. In fact, IoT connections will increase in the next few years across different areas. Conversely, several challenges still need to be faced to enable efficient and secure operations (e.g., interoperability, security, and standards). Furthermore, although efforts have been made to produce datasets composed of attacks against IoT devices, several possible attacks are not considered. Most existing efforts do not consider an extensive network topology with real IoT devices. The main goal of this research is to propose a novel and extensive IoT attack dataset to foster the development of security analytics applications in real IoT operations. To accomplish this, 33 attacks are executed in an IoT topology composed of 105 devices. These attacks are classified into seven categories, namely DDoS, DoS, Recon, Web-based, brute force, spoofing, and Mirai. Finally, all attacks are executed by malicious IoT devices targeting other IoT devices. The dataset is available on the CIC Dataset website.


Assuntos
Benchmarking , Internet das Coisas , Indústrias , Meios de Transporte
4.
Nucleic Acids Res ; 48(9): 5183-5195, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32315033

RESUMO

To extend the frontier of genome editing and enable editing of repetitive elements of mammalian genomes, we made use of a set of dead-Cas9 base editor (dBE) variants that allow editing at tens of thousands of loci per cell by overcoming the cell death associated with DNA double-strand breaks and single-strand breaks. We used a set of gRNAs targeting repetitive elements-ranging in target copy number from about 32 to 161 000 per cell. dBEs enabled survival after large-scale base editing, allowing targeted mutations at up to ∼13 200 and ∼12 200 loci in 293T and human induced pluripotent stem cells (hiPSCs), respectively, three orders of magnitude greater than previously recorded. These dBEs can overcome current on-target mutation and toxicity barriers that prevent cell survival after large-scale genome engineering.


Assuntos
Edição de Genes/métodos , Retroelementos , Proteínas Associadas a CRISPR , Sistemas CRISPR-Cas , Sobrevivência Celular , Endodesoxirribonucleases , Células HEK293 , Humanos , Células-Tronco Pluripotentes Induzidas , Mutação , RNA
5.
FASEB J ; 34(8): 10907-10919, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32632939

RESUMO

Nucleotide oligomerization domain (NOD)-like receptor-12 (NLRP12) has emerged as a negative regulator of inflammation. It is well described that the Th17 cell population increases in patients with early Rheumatoid Arthritis (RA), which correlates with the disease activity. Here, we investigated the role of NLRP12 in the differentiation of Th17 cells and the development of experimental arthritis, using the antigen-induced arthritis (AIA) murine model. We found that Nlrp12-/- mice develop severe arthritis characterized by an exacerbated Th17-mediated inflammatory response with increases in the articular hyperalgesia, knee joint swelling, and neutrophil infiltration. Adoptive transfer of Nlrp12-/- cells into WT mice recapitulated the hyperinflammatory response seen in Nlrp12-/- mice and the treatment with anti-IL-17A neutralizing antibody abrogated arthritis development in Nlrp12-/- mice, suggesting that NLRP12 works as an inhibitor of Th17 cell differentiation. Indeed, Th17 cell differentiation markedly increases in Nlrp12-/- T cells cultured under the Th17-skewing condition. Mechanistically, we found that NLRP12 negatively regulates IL-6-induced phosphorylation of STAT3 in T cells. Finally, pharmacological inhibition of STAT3 reduced Th17 cell differentiation and abrogated hyperinflammatory arthritis observed in Nlrp12-/- mice. Thus, we described a novel role for NLRP12 as a checkpoint inhibitor of Th17 cell differentiation, which controls the severity of experimental arthritis.


Assuntos
Artrite Experimental/metabolismo , Artrite Reumatoide/metabolismo , Diferenciação Celular/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Células Th17/metabolismo , Animais , Artrite Experimental/patologia , Artrite Reumatoide/patologia , Inflamação/metabolismo , Inflamação/patologia , Interleucina-17/metabolismo , Articulações/metabolismo , Articulações/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infiltração de Neutrófilos/fisiologia , Fator de Transcrição STAT3/metabolismo , Células Th17/patologia
6.
Proc Natl Acad Sci U S A ; 115(6): 1262-1267, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29358378

RESUMO

Bio-based production of fatty acids and fatty acid-derived products can enable sustainable substitution of petroleum-derived fuels and chemicals. However, developing new microbial cell factories for producing high levels of fatty acids requires extensive engineering of lipid metabolism, a complex and tightly regulated metabolic network. Here we generated a Saccharomyces cerevisiae platform strain with a simplified lipid metabolism network with high-level production of free fatty acids (FFAs) due to redirected fatty acid metabolism and reduced feedback regulation. Deletion of the main fatty acid activation genes (the first step in ß-oxidation), main storage lipid formation genes, and phosphatidate phosphatase genes resulted in a constrained lipid metabolic network in which fatty acid flux was directed to a large extent toward phospholipids. This resulted in simultaneous increases of phospholipids by up to 2.8-fold and of FFAs by up to 40-fold compared with wild-type levels. Further deletion of phospholipase genes PLB1 and PLB2 resulted in a 46% decrease in FFA levels and 105% increase in phospholipid levels, suggesting that phospholipid hydrolysis plays an important role in FFA production when phospholipid levels are increased. The multiple deletion mutant generated allowed for a study of fatty acid dynamics in lipid metabolism and represents a platform strain with interesting properties that provide insight into the future development of lipid-related cell factories.


Assuntos
Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Saccharomyces cerevisiae/metabolismo , Acil Coenzima A/genética , Acil Coenzima A/metabolismo , Acil-CoA Oxidase/genética , Acil-CoA Oxidase/metabolismo , Coenzima A Ligases/genética , Coenzima A Ligases/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Metabolismo dos Lipídeos/genética , Lisofosfolipase/genética , Lisofosfolipase/metabolismo , Lipídeos de Membrana/biossíntese , Lipídeos de Membrana/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Fosfatidato Fosfatase/genética , Fosfatidato Fosfatase/metabolismo , Fosfolipídeos/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
7.
Neurocrit Care ; 34(2): 581-592, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-32676873

RESUMO

BACKGROUND: The efficacy objective was to determine whether a novel nasopharyngeal catheter could be used to cool the human brain after traumatic brain injury, and the safety objective was to assess the local and systemic effects of this therapeutic strategy. METHODS: This was a prospective, non-randomized, interventional clinical trial that involved five patients with severe traumatic brain injury. The intervention consisted of inducing and maintaining selective brain cooling for 24 h by positioning a catheter in the nasopharynx and circulating cold water inside the catheter in a closed-loop arrangement. Core temperature was maintained at ≥ 35 °C using counter-warming. RESULTS: In all study participants, a brain temperature reduction of ≥ 2 °C was achieved. The mean brain temperature reduction from baseline was 2.5 ± 0.9 °C (P = .04, 95% confidence interval). The mean systemic temperature was 37.3 ± 1.1 °C at baseline and 36.0 ± 0.8 °C during the intervention. The mean difference between the brain temperature and the systemic temperature during intervention was - 1.2 ± 0.8 °C (P = .04). The intervention was well tolerated with no significant changes observed in the hemodynamic parameters. No relevant variations in intracranial pressure and transcranial Doppler were observed. The laboratory results underwent no major changes, aside from the K+ levels and blood counts. The K+ levels significantly varied (P = .04); however, the variation was within the normal range. Only one patient experienced an event of mild localized and superficial nasal discoloration, which was re-evaluated on the seventh day and indicated complete recovery. CONCLUSION: The results suggest that our noninvasive method for selective brain cooling, using a novel nasopharyngeal catheter, was effective and safe for use in humans.


Assuntos
Lesões Encefálicas Traumáticas , Hipotermia Induzida , Temperatura Corporal , Encéfalo/diagnóstico por imagem , Lesões Encefálicas Traumáticas/terapia , Catéteres , Humanos , Nasofaringe , Projetos Piloto , Estudos Prospectivos
8.
Metab Eng ; 57: 51-62, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31526853

RESUMO

Metabolic reprogramming is considered a hallmark of malignant transformation. However, it is not clear whether the network of metabolic reactions expressed by cancers of different origin differ from each other or from normal human tissues. In this study, we reconstructed functional and connected genome-scale metabolic models for 917 primary tumor samples across 13 types based on the probability of expression for 3765 reference metabolic genes in the sample. This network-centric approach revealed that tumor metabolic networks are largely similar in terms of accounted reactions, despite diversity in the expression of the associated genes. On average, each network contained 4721 reactions, of which 74% were core reactions (present in >95% of all models). Whilst 99.3% of the core reactions were classified as housekeeping also in normal tissues, we identified reactions catalyzed by ARG2, RHAG, SLC6 and SLC16 family gene members, and PTGS1 and PTGS2 as core exclusively in cancer. These findings were subsequently replicated in an independent validation set of 3388 genome-scale metabolic models. The remaining 26% of the reactions were contextual reactions. Their inclusion was dependent in one case (GLS2) on the absence of TP53 mutations and in 94.6% of cases on differences in cancer types. This dependency largely resembled differences in expression patterns in the corresponding normal tissues, with some exceptions like the presence of the NANP-encoded reaction in tumors not from the female reproductive system or of the SLC5A9-encoded reaction in kidney-pancreatic-colorectal tumors. In conclusion, tumors expressed a metabolic network virtually overlapping the matched normal tissues, raising the possibility that metabolic reprogramming simply reflects cancer cell plasticity to adapt to varying conditions thanks to redundancy and complexity of the underlying metabolic networks. At the same time, the here uncovered exceptions represent a resource to identify selective liabilities of tumor metabolism.


Assuntos
Redes e Vias Metabólicas , Modelos Biológicos , Proteínas de Neoplasias , Neoplasias , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Neoplasias/metabolismo
9.
Pharmacol Res ; 151: 104580, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31786317

RESUMO

Neutrophils are peripheral immune cells that represent the first recruited innate immune defense against infections and tissue injury. However, these cells can also induce overzealous responses and cause tissue damage. Although the role of neutrophils activating the immune system is well established, only recently their critical implications in neuro-immune interactions are becoming more relevant. Here, we review several aspects of neutrophils in the bidirectional regulation between the nervous and immune systems. First, the role of neutrophils as a diffuse source of acetylcholine and catecholamines is controversial as well as the effects of these neurotransmitters in neutrophil's functions. Second, neutrophils contribute for the activation and sensitization of sensory neurons, and thereby, in events of nociception and pain. In addition, nociceptor activation promotes an axon reflex triggering a local release of neural mediators and provoking neutrophil activation. Third, the recruitment of neutrophils in inflammatory responses in the nervous system suggests these immune cells as innovative targets in the treatment of central infectious, neurological and neurodegenerative disorders. Multidisciplinary studies involving immunologists and neuroscientists are required to define the role of the neurons-neutrophils communication in the pathophysiology of infectious, inflammatory, and neurological disorders.


Assuntos
Neuroimunomodulação , Neutrófilos/imunologia , Animais , Humanos , Imunidade Inata , Inflamação/imunologia , Neurotransmissores/imunologia , Nociceptividade , Dor/imunologia , Células Receptoras Sensoriais/imunologia
10.
Clin Rehabil ; 34(6): 713-722, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32204620

RESUMO

OBJECTIVE: The purpose of this study was to determine the benefits and harms of low-level laser therapy for Achilles tendinopathy. DATA SOURCES: Search strategies were conducted (from inception to February 2020) in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Literatura Latino Americana em Ciências da Saúde e do Caribe (LILACS), Physiotherapy Evidence Database (PEDro), SPORTDiscus, ClinicalTrials.gov, World Health Organization (WHO)-ICTRP and OpenGrey databases, to retrieve all randomized controlled trials that compared laser therapy with inactive/active interventions. REVIEW METHODS: This study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The risk of bias was assessed using the Cochrane Risk of bias table. Meta-analyses were performed on dependence of homogeneity, otherwise results were reported narratively. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: Four trials (119 participants) were analyzed. Laser therapy associated to eccentric exercises when compared to eccentric exercises and sham had very low to low certainty of evidence in pain and function assessment. Despite one trial favored laser therapy at two months (mean difference (MD) -2.55, 95% confidence interval (95% CI) -3.87 to -1.23), the CIs did not include important differences between groups at 3 and 13 months. The function assessment showed an improvement favoring the placebo group at one month (MD 9.19, 95% CI -16.16 to -2.23) and non-significant difference between groups at 3 and 13 months. Adverse events were poorly reported but restricted to minor events related to the exercises. CONCLUSION: The certainty of evidence was low to very low, and the results are insufficient to support the routine use laser therapy for Achilles tendinopathy.


Assuntos
Tendão do Calcâneo , Terapia com Luz de Baixa Intensidade , Tendinopatia/radioterapia , Humanos
11.
Neurocrit Care ; 32(2): 564-574, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31317319

RESUMO

BACKGROUND: Acute brain lesions constitute an alarming public health concern. Neuroprotective therapies have been implemented to stabilize, prevent, or reduce brain lesions, thus improving neurological outcomes and survival rates. Hypothermia is the most effective approach, mainly attributed to the reduction in cellular metabolic activity. Whole-body cooling is currently implemented by healthcare professionals; however, adverse events are frequent, limiting the potential benefits of therapeutic hypothermia. Therefore, selective methods have been developed to reduce adverse events while delivering neuroprotection. Nasopharyngeal approaches are the safest and most effective methods currently considered. Our primary objective was to determine the effects of a novel nasopharyngeal catheter on the brain temperature of pigs. METHODS: In this prospective, non-randomized, interventional experimental trial, 10 crossbred pigs underwent nasopharyngeal cooling for 60 min followed by 15 min of rewarming. Nasopharyngeal catheters were inserted into the left nostril and properly positioned at the nasopharyngeal cavity. RESULTS: Nasopharyngeal cooling was associated with a decrease in brain temperature, which was more significant in the left cerebral hemisphere (p = 0.01). There was a reduction of 1.47 ± 0.86 °C in the first 5 min (p < 0.001), 2.45 ± 1.03 °C within 10 min (p < 0.001), and 4.45 ± 1.36 °C after 1 h (p < 0.001). The brain-core gradient was 4.57 ± 0.87 °C (p < 0.001). Rectal, esophageal, and pulmonary artery temperatures and brain and systemic hemodynamic parameters, remained stable during the procedure. Following brain cooling, values of oxygen partial pressure in brain tissue significantly decreased. No mucosal lesions were detected during nasal, pharyngeal, or oral inspection after nasopharyngeal catheter removal. CONCLUSIONS: In this study, a novel nasopharyngeal cooling catheter effectively induced and maintained exclusive brain cooling when combined with effective counter-warming methods. Exclusive brain cooling was safe with no device-related local or systemic complications and may be desired in selected patient populations.


Assuntos
Temperatura Corporal , Encéfalo/fisiologia , Hipotermia Induzida/métodos , Nasofaringe , Animais , Velocidade do Fluxo Sanguíneo , Encéfalo/irrigação sanguínea , Circulação Cerebrovascular , Esôfago , Estudos de Viabilidade , Feminino , Hipotermia Induzida/instrumentação , Masculino , Artéria Cerebral Média/diagnóstico por imagem , Neuroproteção , Artéria Pulmonar , Reto , Sus scrofa , Suínos , Ultrassonografia Doppler Transcraniana
12.
J Ind Microbiol Biotechnol ; 45(7): 467-480, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29362972

RESUMO

Clustered regularly interspaced short palindromic repeats (CRISPR) is poised to become one of the key scientific discoveries of the twenty-first century. Originating from prokaryotic and archaeal immune systems to counter phage invasions, CRISPR-based applications have been tailored for manipulating a broad range of living organisms. From the different elucidated types of CRISPR mechanisms, the type II system adapted from Streptococcus pyogenes has been the most exploited as a tool for genome engineering and gene regulation. In this review, we describe the different applications of CRISPR/Cas9 technology in the industrial biotechnology field. Next, we detail the current status of the patent landscape, highlighting its exploitation through different companies, and conclude with future perspectives of this technology.


Assuntos
Biotecnologia , Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Regulação da Expressão Gênica , Engenharia Genética/métodos , Bacteriófagos/genética , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/fisiologia , Edição de Genes , Patentes como Assunto
13.
Pharmacol Res ; 117: 1-8, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27979692

RESUMO

Sepsis is one of the main causes of mortality in hospitalized patients. Despite the recent technical advances and the development of novel generation of antibiotics, severe sepsis remains a major clinical and scientific challenge in modern medicine. Unsuccessful efforts have been dedicated to the search of therapeutic options to treat the deleterious inflammatory components of sepsis. Recent findings on neuronal networks controlling immunity raised expectations for novel therapeutic strategies to promote the regulation of sterile inflammation, such as autoimmune diseases. Interesting studies have dissected the anatomical constituents of the so-called "cholinergic anti-inflammatory pathway", suggesting that electrical vagus nerve stimulation and pharmacological activation of beta-2 adrenergic and alpha-7 nicotinic receptors could be alternative strategies for improving inflammatory conditions. However, the literature on infectious diseases, such as sepsis, is still controversial and, therefore, the real therapeutic potential of this neuroimmune pathway is not well defined. In this review, we will discuss the beneficial and detrimental effects of neural manipulation in sepsis, which depend on the multiple variables of the immune system and the nature of the infection. These observations suggest future critical studies to validate the clinical implications of vagal parasympathetic signaling in sepsis treatment.


Assuntos
Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Colinérgicos/farmacologia , Colinérgicos/uso terapêutico , Sepse/tratamento farmacológico , Animais , Humanos , Sistema Imunitário/efeitos dos fármacos , Inflamação/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Nervo Vago/efeitos dos fármacos
14.
Microb Cell Fact ; 16(1): 45, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28298234

RESUMO

BACKGROUND: In vivo production of fatty acid-derived chemicals in Saccharomyces cerevisiae requires strategies to increase the intracellular supply of either acyl-CoA or free fatty acids (FFAs), since their cytosolic concentrations are quite low in a natural state for this organism. Deletion of the fatty acyl-CoA synthetase genes FAA1 and FAA4 is an effective and straightforward way to disable re-activation of fatty acids and drastically increase FFA levels. However, this strategy causes FFA over-accumulation and consequential release to the extracellular medium, which results in a significant loss of precursors that compromises the process yield. In the present study, we aimed for dynamic expression of the fatty acyl-CoA synthetase gene FAA1 to regulate FFA and acyl-CoA pools in order to improve fatty alcohol production yields. RESULTS: We analyzed the metabolite dynamics of a faa1Δ faa4Δ strain constitutively expressing a carboxylic acid reductase from Mycobacterium marinum (MmCAR) and an endogenous alcohol dehydrogenase (Adh5) for in vivo production of fatty alcohols from FFAs. We observed production of fatty acids and fatty alcohols with different rates leading to high levels of FFAs not being converted to the final product. To address the issue, we expressed the MmCAR + Adh5 pathway together with a fatty acyl-CoA reductase from Marinobacter aquaeolei to enable fatty alcohol production simultaneously from FFA and acyl-CoA, respectively. Then, we expressed FAA1 under the control of different promoters in order to balance FFA and acyl-CoA interconversion rates and to achieve optimal levels for conversion to fatty alcohols. Expressing FAA1 under control of the HXT1 promoter led to an increased accumulation of fatty alcohols per OD600 up to 41% while FFA levels were decreased by 63% compared with the control strain. CONCLUSIONS: Fine-tuning and dynamic regulation of key metabolic steps can be used to improve cell factories when the rates of downstream reactions are limiting. This avoids loss of precursors to the extracellular medium or to competing reactions, hereby potentially improving the process yield. The study also provides knowledge of a key point of fatty acid regulation and homeostasis, which can be used for future design of cells factories for fatty acid-derived chemicals.


Assuntos
Ácidos Graxos não Esterificados/metabolismo , Álcoois Graxos/metabolismo , Regulação Fúngica da Expressão Gênica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Álcool Desidrogenase/genética , Coenzima A Ligases/genética , Marinobacter/genética , Engenharia Metabólica/métodos , Mycobacterium marinum/genética , Oxirredutases/genética , Regiões Promotoras Genéticas
15.
Microb Cell Fact ; 16(1): 46, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28298224

RESUMO

BACKGROUND: Transcriptional reprogramming is a fundamental process of living cells in order to adapt to environmental and endogenous cues. In order to allow flexible and timely control over gene expression without the interference of native gene expression machinery, a large number of studies have focused on developing synthetic biology tools for orthogonal control of transcription. Most recently, the nuclease-deficient Cas9 (dCas9) has emerged as a flexible tool for controlling activation and repression of target genes, by the simple RNA-guided positioning of dCas9 in the vicinity of the target gene transcription start site. RESULTS: In this study we compared two different systems of dCas9-mediated transcriptional reprogramming, and applied them to genes controlling two biosynthetic pathways for biobased production of isoprenoids and triacylglycerols (TAGs) in baker's yeast Saccharomyces cerevisiae. By testing 101 guide-RNA (gRNA) structures on a total of 14 different yeast promoters, we identified the best-performing combinations based on reporter assays. Though a larger number of gRNA-promoter combinations do not perturb gene expression, some gRNAs support expression perturbations up to ~threefold. The best-performing gRNAs were used for single and multiplex reprogramming strategies for redirecting flux related to isoprenoid production and optimization of TAG profiles. From these studies, we identified both constitutive and inducible multiplex reprogramming strategies enabling significant changes in isoprenoid production and increases in TAG. CONCLUSION: Taken together, we show similar performance for a constitutive and an inducible dCas9 approach, and identify multiplex gRNA designs that can significantly perturb isoprenoid production and TAG profiles in yeast without editing the genomic context of the target genes. We also identify a large number of gRNA positions in 14 native yeast target pomoters that do not affect expression, suggesting the need for further optimization of gRNA design tools and dCas9 engineering.


Assuntos
Proteínas Associadas a CRISPR/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Endodesoxirribonucleases/metabolismo , RNA Guia de Cinetoplastídeos/genética , Saccharomyces cerevisiae/genética , Transcrição Gênica , Vias Biossintéticas/genética , Proteínas Associadas a CRISPR/genética , Endodesoxirribonucleases/genética , Regiões Promotoras Genéticas , Biologia Sintética/métodos , Terpenos/metabolismo , Triglicerídeos/metabolismo
16.
J Ind Microbiol Biotechnol ; 44(6): 911-922, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28185100

RESUMO

Efficient production of sesquiterpenes in Saccharomyces cerevisiae requires a high flux through the mevalonate pathway. To achieve this, the supply of acetyl-CoA plays a crucial role, partially because nine moles of acetyl-CoA are necessary to produce one mole of farnesyl diphosphate, but also to overcome the thermodynamic constraint imposed on the first reaction, in which acetoacetyl-CoA is produced from two moles of acetyl-CoA by acetoacetyl-CoA thiolase. Recently, a novel acetoacetyl-CoA synthase (nphT7) has been identified from Streptomyces sp. strain CL190, which catalyzes the irreversible condensation of malonyl-CoA and acetyl-CoA to acetoacetyl-CoA and, therefore, represents a potential target to increase the flux through the mevalonate pathway. This study investigates the effect of acetoacetyl-CoA synthase on growth as well as the production of farnesene and compares different homologs regarding their efficiency. While plasmid-based expression of nphT7 did not improve final farnesene titers, the construction of an alternative pathway, which exclusively relies on the malonyl-CoA bypass, was detrimental for growth and farnesene production. The presented results indicate that the overall functionality of the bypass was limited by the efficiency of acetoacetyl-CoA synthase (nphT7). Besides modulation of the expression level, which could be used as a means to partially restore the phenotype, nphT7 from Streptomyces glaucescens showed clearly higher efficiency compared to Streptomyces sp. strain CL190.


Assuntos
Coenzima A Ligases/metabolismo , Saccharomyces cerevisiae/metabolismo , Sesquiterpenos/metabolismo , Acetilcoenzima A/metabolismo , Acetil-CoA C-Acetiltransferase/metabolismo , Acil Coenzima A/metabolismo , Ácido Mevalônico/metabolismo , Streptomyces/enzimologia
17.
Dev Cell ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38823395

RESUMO

Control of cellular identity requires coordination of developmental programs with environmental factors such as nutrient availability, suggesting that perturbing metabolism can alter cell state. Here, we find that nucleotide depletion and DNA replication stress drive differentiation in human and murine normal and transformed hematopoietic systems, including patient-derived acute myeloid leukemia (AML) xenografts. These cell state transitions begin during S phase and are independent of ATR/ATM checkpoint signaling, double-stranded DNA break formation, and changes in cell cycle length. In systems where differentiation is blocked by oncogenic transcription factor expression, replication stress activates primed regulatory loci and induces lineage-appropriate maturation genes despite the persistence of progenitor programs. Altering the baseline cell state by manipulating transcription factor expression causes replication stress to induce genes specific for alternative lineages. The ability of replication stress to selectively activate primed maturation programs across different contexts suggests a general mechanism by which changes in metabolism can promote lineage-appropriate cell state transitions.

18.
Clin Case Rep ; 11(6): e7485, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37305874

RESUMO

The Rumpel-Leede sign, characterized by a non-blanching petechial rash distal to venous occlusion, has historically been associated with thrombocytopenia and capillary fragility. This phenomenon has been observed in various situations involving pressure application, such as tourniquet tests and continuous non-invasive pressure monitoring. Here, we present a case of Rumpel-Leede sign occurring after transulnar percutaneous coronary angiography in a 55-year-old female patient with a history of myocardial infarction. The patient had an uneventful recovery, highlighting the benign nature of the rash and the lack of intervention required. This underscores the importance of recognizing this sign and its association with specific procedures.

19.
BMJ Open Sport Exerc Med ; 9(3): e001641, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37485006

RESUMO

To evaluate aerobic capacity, strength and other physiological, nutritional, and psychological variables which may influence the performance of transgender women (TW) athletes and compare them to cisgender women (CW) and cisgender men (CM) athletes, as well as changes in TW performance over the course of a year. Prospective cohort study including three groups: TW, CW and CM volleyball athletes. Subjects will be comprehensively assessed at two different moments: baseline and after 6-12 months of adequate hormonal therapy. Evaluation will comprise clinical, medical, nutritional and psychological interviews, incremental treadmill cardiopulmonary exercise testing, hand grip strength test, vertical jump test, analysis of sleep quality (Pittsburgh Sleep Quality Index), hormonal profile, echocardiogram, analysis of resting energy expenditure, assessment of bone mass and body composition through dual-energy X-ray absorptiometry scans, and untargeted metabolomic analysis. CW and CM matched by age, body mass index and level of physical activity will undergo a similar evaluation. The assessment of the strength, aerobic capacity, haematological, nutritional and psychological status of TW using gold-standard tests will contribute to understanding the impact of oestrogen therapy on the exercise performance of these athletes and how they compare with CW and CM.

20.
Nat Commun ; 14(1): 6578, 2023 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-37852949

RESUMO

Large genes including several CRISPR-Cas modules like gene activators (CRISPRa) require dual adeno-associated viral (AAV) vectors for an efficient in vivo delivery and expression. Current dual AAV vector approaches have important limitations, e.g., low reconstitution efficiency, production of alien proteins, or low flexibility in split site selection. Here, we present a dual AAV vector technology based on reconstitution via mRNA trans-splicing (REVeRT). REVeRT is flexible in split site selection and can efficiently reconstitute different split genes in numerous in vitro models, in human organoids, and in vivo. Furthermore, REVeRT can functionally reconstitute a CRISPRa module targeting genes in various mouse tissues and organs in single or multiplexed approaches upon different routes of administration. Finally, REVeRT enabled the reconstitution of full-length ABCA4 after intravitreal injection in a mouse model of Stargardt disease. Due to its flexibility and efficiency REVeRT harbors great potential for basic research and clinical applications.


Assuntos
Edição de Genes , Trans-Splicing , Humanos , Animais , Camundongos , Trans-Splicing/genética , Terapia Genética , Doença de Stargardt , Vetores Genéticos/genética , Dependovirus/genética , Dependovirus/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa