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1.
Klin Padiatr ; 236(2): 73-79, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38286410

RESUMO

Pulmonary alveolar proteinosis (PAP) is an umbrella term used to refer to a pulmonary syndrome which is characterized by excessive accumulation of surfactant in the lungs of affected individuals. In general, PAP is a rare lung disease affecting children and adults, although its prevalence and incidence is variable among different countries. Even though PAP is a rare disease, it is a prime example on how modern medicine can lead to new therapeutic concepts, changing ways and techniques of (genetic) diagnosis which ultimately led into personalized treatments, all dedicated to improve the function of the impaired lung and thus life expectancy and quality of life in PAP patients. In fact, new technologies, such as new sequencing technologies, gene therapy approaches, new kind and sources of stem cells and completely new insights into the ontogeny of immune cells such as macrophages have increased our understanding in the onset and progression of PAP, which have paved the way for novel therapeutic concepts for PAP and beyond. As of today, classical monocyte-derived macrophages are known as important immune mediator and immune sentinels within the innate immunity. Furthermore, macrophages (known as tissue resident macrophages (TRMs)) can also be found in various tissues, introducing e. g. alveolar macrophages in the broncho-alveolar space as crucial cellular determinants in the onset of PAP and other lung disorders. Given recent insights into the onset of alveolar macrophages and knowledge about factors which impede their function, has led to the development of new therapies, which are applied in the context of PAP, with promising implications also for other diseases in which macrophages play an important role. Thus, we here summarize the latest insights into the various forms of PAP and introduce new pre-clinical work which is currently conducted in the framework of PAP, introducing new therapies for children and adults who still suffer from this severe, potentially life-threatening disease.


Assuntos
Proteinose Alveolar Pulmonar , Adulto , Criança , Humanos , Proteinose Alveolar Pulmonar/diagnóstico , Proteinose Alveolar Pulmonar/genética , Proteinose Alveolar Pulmonar/terapia , Qualidade de Vida , Pulmão , Macrófagos Alveolares
2.
J Am Soc Nephrol ; 34(8): 1366-1380, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37367205

RESUMO

SIGNIFICANCE STATEMENT: Treatment of acute, crescentic glomerulonephritis (GN) consists of unspecific and potentially toxic immunosuppression. T cells are central in the pathogenesis of GN, and various checkpoint molecules control their activation. The immune checkpoint molecule B and T-lymphocyte attenuator (BTLA) has shown potential for restraining inflammation in other T-cell-mediated disease models. To investigate its role in GN in a murine model of crescentic nephritis, the authors induced nephrotoxic nephritis in BTLA-deficient mice and wild-type mice. They found that BTLA has a renoprotective role through suppression of local Th1-driven inflammation and expansion of T regulatory cells and that administration of an agonistic anti-BTLA antibody attenuated experimental GN. These findings suggest that antibody-based modulation of BTLA may represent a treatment strategy in human glomerular disease. BACKGROUND: Modulating T-lymphocytes represents a promising targeted therapeutic option for glomerulonephritis (GN) because these cells mediate damage in various experimental and human GN types. The immune checkpoint molecule B and T-lymphocyte attenuator (BTLA) has shown its potential to restrain inflammation in other T-cell-mediated disease models. Its role in GN, however, has not been investigated. METHODS: We induced nephrotoxic nephritis (NTN), a mouse model of crescentic GN, in Btla -deficient ( BtlaKO ) mice and wild-type littermate controls and assessed disease severity using functional and histologic parameters at different time points after disease induction. Immunologic changes were comprehensively evaluated by flow cytometry, RNA sequencing, and in vitro assays for dendritic cell and T-cell function. Transfer experiments into Rag1KO mice confirmed the observed in vitro findings. In addition, we evaluated the potential of an agonistic anti-BTLA antibody to treat NTN in vivo . RESULTS: The BtlaKO mice developed aggravated NTN, driven by an increase of infiltrating renal Th1 cells. Single-cell RNA sequencing showed increased renal T-cell activation and positive regulation of the immune response. Although BTLA-deficient regulatory T cells (Tregs) exhibited preserved suppressive function in vitro and in vivo , BtlaKO T effector cells evaded Treg suppression. Administration of an agonistic anti-BTLA antibody robustly attenuated NTN by suppressing nephritogenic T effector cells and promoting Treg expansion. CONCLUSIONS: In a model of crescentic GN, BTLA signaling effectively restrained nephritogenic Th1 cells and promoted regulatory T cells. Suppression of T-cell-mediated inflammation by BTLA stimulation may prove relevant for a broad range of conditions involving acute GN.


Assuntos
Glomerulonefrite Membranoproliferativa , Glomerulonefrite , Nefrite , Camundongos , Humanos , Animais , Proteínas de Checkpoint Imunológico , Glomerulonefrite/patologia , Glomerulonefrite Membranoproliferativa/complicações , Inflamação/complicações , Camundongos Endogâmicos C57BL
3.
Int J Mol Sci ; 25(7)2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38612567

RESUMO

Autophagy, a catabolic process orchestrating the degradation of proteins and organelles within lysosomes, is pivotal for maintaining cellular homeostasis. However, its dual role in cancer involves preventing malignant transformation while fostering progression and therapy resistance. Vacuole Membrane Protein 1 (VMP1) is an essential autophagic protein whose expression, per se, triggers autophagy, being present in the whole autophagic flux. In pancreatic cancer, VMP1-whose expression is linked to the Kirsten Rat Sarcoma Virus (KRAS) oncogene-significantly contributes to disease promotion, progression, and chemotherapy resistance. This investigation extends to breast cancer, colon cancer, hepatocellular carcinoma, and more, highlighting VMP1's nuanced nature, contingent on specific tissue contexts. The examination of VMP1's interactions with micro-ribonucleic acids (miRNAs), including miR-21, miR-210, and miR-124, enhances our understanding of its regulatory network in cancer. Additionally, this article discusses VMP1 gene fusions, especially with ribosomal protein S6 kinase B1 (RPS6KB1), shedding light on potential implications for tumor malignancy. By deciphering the molecular mechanisms linking VMP1 to cancer progression, this exploration paves the way for innovative therapeutic strategies to disrupt these pathways and potentially improve treatment outcomes.


Assuntos
Carcinoma Hepatocelular , Neoplasias do Colo , Neoplasias Hepáticas , Proteínas de Membrana , MicroRNAs , Humanos , Autofagia/genética , Proteínas de Membrana/genética , Proteínas de Membrana/fisiologia , MicroRNAs/genética
4.
Int J Mol Sci ; 25(12)2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38928073

RESUMO

The Cystic Fibrosis Conductance Transmembrane Regulator gene encodes for the CFTR ion channel, which is responsible for the transport of chloride and bicarbonate across the plasma membrane. Mutations in the gene result in impaired ion transport, subsequently leading to perturbed secretion in all exocrine glands and, therefore, the multi-organ disease cystic fibrosis (CF). In recent years, several studies have reported on CFTR expression in immune cells as demonstrated by immunofluorescence, flow cytometry, and immunoblotting. However, these data are mainly restricted to single-cell populations and show significant variation depending on the methodology used. Here, we investigated CFTR transcription and protein expression using standardized protocols in a comprehensive panel of immune cells. Methods: We applied a high-resolution Western blot protocol using a combination of highly specific monoclonal CFTR antibodies that have been optimized for the detection of CFTR in epithelial cells and healthy primary immune cell subpopulations sorted by flow cytometry and used immortalized cell lines as controls. The specificity of CFTR protein detection was controlled by peptide competition and enzymatic Peptide-N-Glycosidase-F (PNGase) digest. CFTR transcripts were analyzed using quantitative real-time PCR and normalized to the level of epithelial T84 cells as a reference. Results: CFTR mRNA expression could be shown for primary CD4+ T cells, NK cells, as well as differentiated THP-1 and Jurkat T cells. In contrast, we failed to detect CFTR transcripts for CD14+ monocytes and undifferentiated THP-1 cells, as well as for B cells and CD8+ T cells. Prominent immunoreactive bands were detectable by immunoblotting with the combination of four CFTR antibodies targeting different epitopes of the CFTR protein. However, in biosamples of non-epithelial origin, these CFTR-like protein bands could be unmasked as false positives through peptide competition or PNGase digest, meaning that the observed mRNA transcripts were not necessarily translated into CFTR proteins, which could be detected via immunoblotting. Our results confirm that mRNA expression in immune cells is many times lower than in that cells of epithelial origin. The immunoreactive signals in immune cells turned out to be false positives, and may be provoked by the presence of a high-affinity protein with a similar epitope. Non-specific binding (e.g., Fab-interaction with glycosyl branches) might also contribute to false positive signals. Our findings highlight the necessity of accurate controls, such as CFTR-negative cells, as well as peptide competition and glycolytic digest in order to identify genuine CFTR protein by immunoblotting. Our data suggest, furthermore, that CFTR protein expression data from techniques such as histology, for which the absence of a molecular weight or other independent control prevents the unmasking of false positive immunoreactive signals, must be interpreted carefully as well.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística , Leucócitos Mononucleares , RNA Mensageiro , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Leucócitos Mononucleares/metabolismo , Western Blotting , Reação em Cadeia da Polimerase em Tempo Real/métodos , Fibrose Cística/metabolismo , Fibrose Cística/genética , Células Matadoras Naturais/metabolismo , Citometria de Fluxo/métodos , Linfócitos T CD4-Positivos/metabolismo
5.
Int J Mol Sci ; 24(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36902354

RESUMO

The coronavirus disease pandemic, which profoundly reshaped the world in 2019 (COVID-19), and is currently ongoing, has affected over 200 countries, caused over 500 million cumulative cases, and claimed the lives of over 6.4 million people worldwide as of August 2022. The causative agent is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Depicting this virus' life cycle and pathogenic mechanisms, as well as the cellular host factors and pathways involved during infection, has great relevance for the development of therapeutic strategies. Autophagy is a catabolic process that sequesters damaged cell organelles, proteins, and external invading microbes, and delivers them to the lysosomes for degradation. Autophagy would be involved in the entry, endo, and release, as well as the transcription and translation, of the viral particles in the host cell. Secretory autophagy would also be involved in developing the thrombotic immune-inflammatory syndrome seen in a significant number of COVID-19 patients that can lead to severe illness and even death. This review aims to review the main aspects that characterize the complex and not yet fully elucidated relationship between SARS-CoV-2 infection and autophagy. It briefly describes the key concepts regarding autophagy and mentions its pro- and antiviral roles, while also noting the reciprocal effect of viral infection in autophagic pathways and their clinical aspects.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Autofagia , Antivirais/farmacologia , Lisossomos/metabolismo
6.
Int J Mol Sci ; 24(16)2023 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-37629161

RESUMO

Autophagy is a tightly regulated catabolic process involved in the degradation and recycling of proteins and organelles. Ubiquitination plays an important role in the regulation of autophagy. Vacuole Membrane Protein 1 (VMP1) is an essential autophagy protein. The expression of VMP1 in pancreatic cancer stem cells carrying the activated Kirsten rat sarcoma viral oncogene homolog (KRAS) triggers autophagy and enables therapy resistance. Using biochemical and cellular approaches, we identified ubiquitination as a post-translational modification of VMP1 from the initial steps in autophagosome biogenesis. VMP1 remains ubiquitinated as part of the autophagosome membrane throughout autophagic flux until autolysosome formation. However, VMP1 is not degraded by autophagy, nor by the ubiquitin-proteasomal system. Mass spectrometry and immunoprecipitation showed that the cell division cycle protein cdt2 (Cdt2), the substrate recognition subunit of the E3 ligase complex associated with cancer, cullin-RING ubiquitin ligase complex 4 (CRL4), is a novel interactor of VMP1 and is involved in VMP1 ubiquitination. VMP1 ubiquitination decreases under the CRL inhibitor MLN4924 and increases with Cdt2 overexpression. Moreover, VMP1 recruitment and autophagosome formation is significantly affected by CRL inhibition. Our results indicate that ubiquitination is a novel post-translational modification of VMP1 during autophagy in human tumor cells. VMP1 ubiquitination may be of clinical relevance in tumor-cell-therapy resistance.


Assuntos
Proteínas de Membrana , Neoplasias , Processamento de Proteína Pós-Traducional , Humanos , Autofagia/genética , Macroautofagia , Proteínas de Membrana/metabolismo , Ubiquitina , Ubiquitinação
7.
J Stroke Cerebrovasc Dis ; 32(5): 107058, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36940565

RESUMO

OBJECTIVES: Stroke epidemiology varies among different populations. The burden of stroke is high in low- and middle-income countries. Reliable population data is needed to assess the impact of stroke and to develop policies aimed to improve stroke care in our region. EstEPA is a population-based project assessing prevalence, incidence, mortality and burden of stroke in General Villegas Department, Buenos Aires, Argentina (pop=30,864 inhabitants). We determined incidence of stroke (first-ever and recurrent stroke) and stroke case-fatality rate from 2017 to 2020. METHODS: First-ever strokes, recurrent strokes and transient ischemic attacks were ascertained and case-fatality rate was obtained. Diagnoses were based on standard AHA/WHO definitions. Study population included all persons residing in General Villegas during the three-year period. Hospitals, households, nursing homes, death certificates and several overlapping sources were surveyed. RESULTS: We assessed 92,592 person-years. There were 155 cerebrovascular events aged 70 years (SD ± 13 years), of which 115 were first-ever strokes (74%), 21 recurrent strokes (13.5%) and 19 transient ischemic attacks (12.5%). The crude overall incidence rate of first-ever strokes was 124.2 per 100,000 population (86.9 per 100,000 [95% CI 58.5-115.2] when standardized by WHO World population and 109.7 per 100,000 [95% CI 89.7-129.8] when standardized by Argentine population) and 317.0 per 100,000 population in subjects older than 40 years. Case fatality rate at 30 days of first-ever strokes was 27%. CONCLUSION: In this population-based comprehensive stroke epidemiological study in Argentina, first-ever stroke incidence in an urban population was 124.2 per 100,000 population (86.9 per 100,000 adjusted by the WHO World population). This is lower than the incidence in other countries in the region and similar to a recent incidence study in Argentina. It is also comparable to reported incidence in most middle- and high-income countries. Stroke case-fatality rate was comparable to other population-based Latin-American studies.


Assuntos
Ataque Isquêmico Transitório , Acidente Vascular Cerebral , Humanos , Ataque Isquêmico Transitório/diagnóstico , Ataque Isquêmico Transitório/epidemiologia , Incidência , Argentina/epidemiologia , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Casas de Saúde
8.
BMC Microbiol ; 22(1): 52, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35148684

RESUMO

Citrus greening, also known as Huanglongbing (HLB), is a devastating citrus plant disease caused predominantly by Liberibacter asiaticus. While nearly all Liberibacter species remain uncultured, here we used the culturable L. crescens BT-1 as a model to examine physiological changes in response to the variable osmotic conditions and nutrient availability encountered within the citrus host. Similarly, physiological responses to changes in growth temperature and dimethyl sulfoxide concentrations were also examined, due to their use in many of the currently employed therapies to control the spread of HLB. Sublethal heat stress was found to induce the expression of genes related to tryptophan biosynthesis, while repressing the expression of ribosomal proteins. Osmotic stress induces expression of transcriptional regulators involved in expression of extracellular structures, while repressing the biosynthesis of fatty acids and aromatic amino acids. The effects of osmotic stress were further evaluated by quantifying biofilm formation of L. crescens in presence of increasing sucrose concentrations at different stages of biofilm formation, where sucrose-induced osmotic stress delayed initial cell attachment while enhancing long-term biofilm viability. Our findings revealed that exposure to osmotic stress is a significant contributing factor to the long term survival of L. crescens and, possibly, to the pathogenicity of other Liberibacter species.


Assuntos
Biofilmes/crescimento & desenvolvimento , Citrus/microbiologia , Viabilidade Microbiana , Pressão Osmótica , Doenças das Plantas/microbiologia , Liberibacter/patogenicidade , Liberibacter/fisiologia , Fatores de Tempo
9.
Environ Microbiol ; 23(11): 7121-7138, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34431209

RESUMO

In Liberibacter asiaticus, PrbP is a transcriptional regulatory protein involved in survival and persistence during host infection. Tolfenamic acid was previously found to inhibit interactions between PrbP and the promotor region of rplK, resulting in reduced survival of L. asiaticus in the citrus host. In this study, we performed transcriptome analyses to elucidate the PrbP regulon in L. crescens, as it is phylogenetically the closest related species to L. asiaticus that can be grown in laboratory conditions. Chemical inhibition of PrbP with tolfenamic acid revealed that PrbP is involved in the regulation of diverse cellular processes, including stress response, cell motility, cell cycle and biofilm formation. In vitro DNA binding and bacterial two-hybrid assays also suggested that PrbP is a global regulator of multiple transcription factors (RpoH, VisN, PleD, MucR, MocR and CtrA) at both transcriptional and/or post-transcriptional levels. Sub-lethal concentrations of tolfenamic acid significantly reduced the attachment of L. crescens during biofilm formation and decreased long-term persistence in biofilm structures. Overall, our findings show the importance of PrbP in regulating diverse biological processes through direct and indirect interactions with other transcriptional regulators in L. crescens.


Assuntos
Citrus , Rhizobiaceae , Biofilmes , Citrus/microbiologia , Liberibacter , Doenças das Plantas/microbiologia , Rhizobiaceae/genética
10.
New Phytol ; 229(2): 979-993, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33070379

RESUMO

Cytokinin and auxin are key regulators of plant growth and development. During the last decade transport mechanisms have turned out to be the key for the control of local and long-distance hormone distributions. In contrast with auxin, cytokinin transport is poorly understood. Here, we show that Arabidopsis thaliana AZG2, a member of the AZG purine transporter family, acts as cytokinin transporter involved in root system architecture determination. Even though purines are substrates for both AZG1 and AZG2, we found distinct transport mechanisms. The expression of AZG2 is restricted to a small group of cells surrounding the lateral root (LR) primordia and induced by auxins. Compared to the wild-type (WT), mutants carrying loss-of-function alleles of AZG2 have higher LR density, suggesting that AZG2 is part of a regulatory pathway in LR emergence. Moreover, azg2 is partially insensitive to exogenous cytokinin, which is consistent with the observation that the cytokinin reporter TCSnpro :GFP showed lower fluorescence signal in the roots of azg2 compared to the WT. These results indicate a defective cytokinin signalling pathway in the region of LR primordia. The integration of AZG2 subcellular localization and cytokinin transport capacity data allowed us to propose a local cytokinin : auxin signalling model for the regulation of LR emergence.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Citocininas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos
11.
Plant Physiol ; 182(3): 1310-1325, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31862838

RESUMO

Allantoin is a purine oxidative product involved in long distance transport of organic nitrogen in nodulating legumes and was recently shown to play a role in stress tolerance in other plants. The subcellular localization of enzymes that catalyze allantoin synthesis and degradation indicates that allantoin is produced in peroxisomes and degraded in the endoplasmic reticulum (ER). Although it has been determined that allantoin is mostly synthesized in roots and transported to shoots either for organic nitrogen translocation in legumes or for plant protection during stress in Arabidopsis (Arabidopsis thaliana), the mechanism and molecular components of allantoin export from root cells are still unknown. AtUPS5 (Arabidopsis UREIDE PERMEASE 5) is a transmembrane protein that transports allantoin with high affinity when expressed in yeast. The subcellular fate of splicing variants AtUPS5L (long) and AtUPS5S (short) was studied by tagging them with fluorescent proteins in their cytosolic loops. The capability of these fusion proteins to complement the function of the native proteins was demonstrated by nutritional and salt stress experiments. Both variants localized to the ER, but the AtUPS5L variant was also detected in the trans-Golgi network/early endosome and at the plasma membrane. AtUPS5L and AtUPS5S localization indicates that they could have different roles in allantoin distribution between subcellular compartments. Our data suggest that under nonstress conditions UPS5L and UPS5S may function in allantoin degradation for nutrient recycling, whereas under stress, both genes may be involved in vesicular export allowing allantoin translocation from roots to shoots.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Raízes de Plantas/metabolismo , Alantoína/metabolismo , Regulação da Expressão Gênica de Plantas , Nitrogênio/metabolismo
12.
Eur J Neurol ; 28(6): 1901-1909, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33730413

RESUMO

BACKGROUND AND PURPOSE: Despite enormous advances in identifying genetic variants responsible for many neurological diseases, access to genetic testing may be limited in clinical practice. The objective of this study was to assess worldwide access to genetic tests for movement disorders and factors impacting their utilization. METHODS: The Rare Movement Disorders Study Group of the International Parkinson and Movement Disorder Society designed an online survey electronically mailed to all 7815 members. RESULTS: Survey data completed by 1269 participants from 109 countries were analysed. Limited access to geneticists and genetic counsellors was reported in many world regions compared to Europe and North America. Availability of genetic testing was limited, with rates of access lower than 50%. Genetic testing for chorea was the most commonly available. For parkinsonism, dystonia, ataxia, hereditary spastic paraplegias and metabolic disorders, there was limited access to genetic testing in all countries compared to Europe and North America, with significant differences found for Africa, Central/South America, Asia. In many regions, genetic testing was supported by either private or public funding. Genetic testing was free of charge in Europe according to 63.5% of respondents. In North America, Africa, Central/South America, Asia and the Middle East access to free of charge genetic testing was by far significantly lower compared to Europe. CONCLUSIONS: This survey highlights difficulties in accessing genetic testing and individuals with expertise in genetics at the worldwide level. In addition, major disparities in genetic testing amongst world regions are highlighted, probably due to a variety of factors including financial barriers.


Assuntos
Transtornos dos Movimentos , Ásia , Europa (Continente) , Testes Genéticos , Humanos , Oriente Médio , Transtornos dos Movimentos/genética
13.
J Plant Res ; 133(5): 739-749, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32740857

RESUMO

Plants can respond and adapt to changes in the internal content of carbon and nitrogen by using organic compounds that widely differ in their carbon/nitrogen ratio. Among them, the amides asparagine and glutamine are believed to be preferred by most plants, including Arabidopsis. However, increases in the ureides allantoin and/or allantoate concentrations have been observed in different plant species under several environmental conditions. In this work, changes in the ratio between carbon skeletons and reduced nitrogen were investigated by varying the concentrations of nitrogen and sucrose in the growth media. Allantoin accumulation was observed when plants were grown in media with high ammonia concentrations. This increase was reverted by adding sucrose as additional carbon source. Moreover, mutant plants with a decreased capability to degrade allantoin showed a compromised growth compared to WT in ammonia supplemented media. Together, our results indicate that allantoin accumulation is induced by low carbon/nitrogen ratio and suggest that its degradation is critical for proper plant growth and development.


Assuntos
Alantoína , Proteínas de Arabidopsis , Arabidopsis , Alantoína/metabolismo , Amidoidrolases , Arabidopsis/genética , Arabidopsis/metabolismo , Nitrogênio , Folhas de Planta
14.
Environ Microbiol ; 21(12): 4822-4835, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31631506

RESUMO

Liberibacter asiaticus is the prevalent causative pathogen of Huanglongbing or citrus greening disease, which has resulted in a devastating crisis in the citrus industry. A thorough understanding of this pathogen's physiology and mechanisms to control cell survival is critical in the identification of therapeutic targets. YbeY is a highly conserved bacterial RNase that has been implicated in multiple roles. In this study, we evaluated the biochemical characteristics of the L. asiaticus YbeY (CLIBASIA_01560) and assessed its potential as a target for antimicrobials. YbeYLas was characterized as an endoribonuclease with activity on 3' and 5' termini of 16S and 23S rRNAs, and the capacity to suppress the E. coli ΔybeY phenotype. We predicted the YbeYLas protein:ligand interface and subsequently identified a flavone compound, luteolin, as a selective inhibitor. Site-directed mutagenesis was subsequently used to identify key residues involved in the catalytic activity of YbeYLas. Further evaluation of naturally occurring flavonoids in citrus trees indicated that both flavones and flavonols had potent inhibitory effects on YbeYLas . Luteolin was subsequently examined for efficacy against L. asiaticus in Huanglongbing-infected citrus trees, where a significant reduction in L. asiaticus gene expression was observed.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/química , Flavonoides/química , Rhizobiaceae/enzimologia , Ribonucleases/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Citrus/microbiologia , Inibidores Enzimáticos/metabolismo , Flavonoides/metabolismo , Doenças das Plantas/microbiologia , Rhizobiaceae/química , Rhizobiaceae/genética , Ribonucleases/química , Ribonucleases/genética , Ribonucleases/metabolismo
15.
Appl Environ Microbiol ; 85(4)2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30552192

RESUMO

In Liberibacter asiaticus, PrbP is an important transcriptional accessory protein that regulates gene expression through interactions with the RNA polymerase ß-subunit and a specific sequence on the promoter region. The constitutive expression of prbP observed upon chemical inactivation of PrbP-DNA interactions in vivo indicated that the expression of prbP was not autoregulated at the level of transcription. This observation suggested that a modulatory mechanism via protein-protein interactions may be involved. In silico genome association analysis identified FerR (CLIBASIA_01505), a putative ferredoxin-like protein, as a PrbP-interacting protein. Using a bacterial two-hybrid system and immunoprecipitation assays, interactions between PrbP and FerR were confirmed. In vitro transcription assays were used to show that FerR can increase the activity of PrbP by 16-fold when present in the PrbP-RNA polymerase reaction mixture. The FerR protein-protein interaction surface was predicted by structural modeling and followed by site-directed mutagenesis. Amino acids V20, V23, and C40 were identified as the most important residues in FerR involved in the modulation of PrbP activity in vitro The regulatory mechanism of FerR abundance was examined at the transcription level. In contrast to prbP of L. asiaticus (prbPLas), mRNA levels of ferR of L. asiaticus (ferRLas) are induced by an increase in osmotic pressure. The results of this study revealed that the activity of the transcriptional activator PrbPLas is modulated via interactions with FerRLas The induction of ferRLas expression by osmolarity provides insight into the mechanisms of adjusting gene expression in response to host environmental signals in L. asiaticusIMPORTANCE The rapid spread and aggressive progression of huanglongbing (HLB) in the major citrus-producing areas have raised global recognition of and vigilance to this disease. As a result, the causative agent, Liberibacter asiaticus, has been investigated from various perspectives. However, gene expression regulatory mechanisms that are important for the survival and persistence of this intracellular pathogen remain largely unexplored. PrbP is a transcriptional accessory protein important for L. asiaticus survival in the plant host. In this study, we investigated the interactions between PrbP in L. asiaticus (PrbPLas) and a ferredoxin-like protein (FerR) in L. asiaticus, FerRLas We show that the presence of FerR stabilizes and augments the activity of PrbPLas In addition, we demonstrate that the expression of ferR is induced by increases in osmolarity in Liberibacter crescens Altogether, these results suggest that FerRLas and PrbPLas may play important roles in the regulation of gene expression in response to changing environmental signals during L. asiaticus infection in the citrus host.


Assuntos
Ferredoxinas/genética , Ferredoxinas/metabolismo , Rhizobiaceae/genética , Rhizobiaceae/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Citrus/microbiologia , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Interações Hospedeiro-Patógeno , Modelos Moleculares , Pressão Osmótica , Doenças das Plantas/microbiologia , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas
16.
Diabetes Obes Metab ; 21(4): 1010-1017, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30565386

RESUMO

AIM: To evaluate the long-term cost-effectiveness of an intensification strategy with sodium-glucose co-transporter-2 (SGLT2) inhibitors (pathway 1) compared with NPH insulin (pathway 2) in patients with type 2 diabetes (T2D) in the United Kingdom who were not at goal on metformin and sitagliptin. METHODS: Cost-effectiveness analysis was performed using the well-established, validated IQVIA CORE Diabetes Model from the payer perspective over a patient's lifetime. Randomized clinical trials informed treatment effect measures, while public or published sources informed economic inputs. Scenario analyses of glycated haemoglobin (HbA1c), hypoglycaemia rate, body mass index effects, SGLT2 inhibitor cardiovascular protective effects, and population characteristics were conducted to assess the robustness of results. RESULTS: Pathway 1 increased life-years and quality-adjusted life-years (QALYs) compared with pathway 2 (13.49 vs. 13.37, and 9.40 vs. 9.22, respectively). Additional drug costs in pathway 1 were offset by diabetes-related complication decreases, leading to slightly lower direct medical costs for pathway 1 (£25747 vs £26095). Pathway 1 was therefore cost-neutral (no interpretable incremental cost-effectiveness ratio), while improving clinical outcomes. Scenario analyses consistently showed cost-neutrality or cost-effectiveness of pathway 1. The highest result remained less than £3000/QALY, reflecting older patients (≥65 years) with lower baseline HbA1c (7%). CONCLUSIONS: For UK patients with T2D not at goal on metformin and sitagliptin therapy, treatment intensification with SGLT2 inhibitors prior to NPH insulin is cost-neutral or cost-effective compared with immediate NPH insulin intensification.


Assuntos
Análise Custo-Benefício , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Insulina Isófana/uso terapêutico , Metformina/uso terapêutico , Fosfato de Sitagliptina/uso terapêutico , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Adulto , Idoso , Glicemia/metabolismo , Complicações do Diabetes/economia , Diabetes Mellitus Tipo 2/economia , Diabetes Mellitus Tipo 2/metabolismo , Custos de Medicamentos/estatística & dados numéricos , Quimioterapia Combinada , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemiantes/economia , Insulina Isófana/economia , Masculino , Pessoa de Meia-Idade , Anos de Vida Ajustados por Qualidade de Vida , Inibidores do Transportador 2 de Sódio-Glicose/economia , Reino Unido
17.
Am J Hum Biol ; 31(5): e23292, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31290197

RESUMO

OBJECTIVE: To describe the non-high-density lipoprotein cholesterol (non-HDL-C) as mean and percentiles by age and sex in Argentinean indigenous schoolchildren living at 3750 m, contrasting these estimates with those reported in the 2011-2012 National Center for Health Statistics reference population (NHANES). METHODS: Non-HDL-C was calculated as total cholesterol-HDL-C. Analyses incorporated sampling weights for age and sex to obtain unbiased estimates. Sex- and age-specific smoothed percentile curves were performed with Cole's LMS method. RESULTS: A total of 236 (49% males) children from San Antonio de los Cobres (SAC) were evaluated twice and compared with 1409 NHANES children. Non-HDL-C values were 4 mg/dL higher in SAC than in NHANES (109 vs 105 mg/dL, respectively). Trends in non-HDL-C 50th percentile in females differed between ages 6 to 7 and 8 years; in SAC non-HDL-C decreased from 111 to 104 mg/dL, NHANES levels remained stable from103 to 104 mg/dL. Among children aged 9 to10 years, non-HDL-C increased from 114 mg/dL to 117 mg/dL in SAC, but decreased from 113 to 107 mg/dL in NHANES. Between ages 12 and 13 years, non-HDL-C increased from 108 to 120 mg/dL in SAC, and remained steady from105 to 106 mg/dL in NHANES. The 50th percentile of non-HDL-C in males showed similar trends except for ages 6 to 7 to age 8 when non-HDL-C remained stable from 106 to 107 mg/dL in SAC, and increased from 98 mg/dL to 104 mg/dL in NHANES. CONCLUSIONS: Non-HDL-C levels in children vary with age, sex, ethnicity, and altitude. Different patterns in non-HDL-C were observed for girls in SAC compared with NHANES. However, more stable patterns were observed in boys in both groups.


Assuntos
Colesterol/sangue , Indígenas Sul-Americanos/estatística & dados numéricos , Lipoproteínas/sangue , Adolescente , Fatores Etários , Argentina , Criança , Feminino , Humanos , Masculino , Inquéritos Nutricionais , Fatores Sexuais , Estados Unidos
19.
J Stroke Cerebrovasc Dis ; 28(1): 56-62, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30292417

RESUMO

BACKGROUND: Epidemiological data on stroke is scarce in Latin America. Estudio Epidemiológico Poblacional sobre Accidente Cerebrovascular (EstEPA) is a population-based program planned to assess prevalence, incidence, mortality, and burden of disease for stroke in the Department of General Villegas, province of Buenos Aires, Argentina. METHODS AND DESIGN: Prevalence study will consist of a two-phase survey approach in the urban area of General Villegas. First, trained social workers with a structured questionnaire will collect data in 2000 randomly selected housing units. Those subjects screened positive for possible strokes will be interviewed and examined by stroke neurologists to confirm diagnosis. The incidence study will be performed according to the methodology of WHO STEPS stroke surveillance manual and will detect all new strokes in the department during a 5-year period. General and disease-specific mortality rates will be assessed monthly during a 5-year period, using different sources of information. To assess the overall burden of cerebrovascular disease, disability adjusted life years will be calculated. DISCUSSION: EstEPA will assess for the first time all aspects of stroke epidemiology in Argentina. Its results will help to implement population-based interventions and to properly allocate public health resources.


Assuntos
Acidente Vascular Cerebral/epidemiologia , Argentina/epidemiologia , Efeitos Psicossociais da Doença , Estudos Transversais , Feminino , Humanos , Incidência , Masculino , Prevalência , Projetos de Pesquisa , Inquéritos e Questionários
20.
BMC Microbiol ; 18(1): 201, 2018 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-30497377

RESUMO

BACKGROUND: The aggressive spread of Liberibacter asiaticus, a bacterium closely associated with citrus greening, has given rise to an acute crisis in the citrus industry, making it imperative to expand the scientific knowledge base regarding L. asiaticus. Despite several endeavors to culture L. asiaticus, this bacterium has yet to be maintained in axenic culture, rendering identification and analysis of potential treatment targets challenging. Accordingly, a thorough understanding of biological mechanisms involved in the citrus host-microbe relationship is critical as a means of directing the search for future treatment targets. In this study, we evaluate the biochemical characteristics of CLIBASIA_01175, renamed LdtP (L,D-transpeptidase). Surrogate strains were used to evaluate its potential biological significance in gram-negative bacteria. A strain of E. coli carrying quintuple knock-outs of all genes encoding L,D-transpeptidases was utilized to demonstrate the activity of L. asiaticus LdtP. RESULTS: This complementation study demonstrated the periplasmic localization of mature LdtP and provided evidence for the biological role of LdtP in peptidoglycan modification. Further investigation highlighted the role of LdtP as a periplasmic esterase involved in modification of the lipid A moiety of the lipopolysaccharide. This work described, for the first time, an enzyme of the L,D-transpeptidase family with moonlighting enzyme activity directed to the modification of the bacterial cell wall and LPS. CONCLUSIONS: Taken together, the data indicates that LdtP is a novel protein involved in an alternative pathway for modification of the bacterial cell, potentially affording L. asiaticus a means to survive within the host.


Assuntos
Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Peptidil Transferases/isolamento & purificação , Peptidil Transferases/metabolismo , Rhizobiaceae/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Parede Celular/enzimologia , Parede Celular/genética , Lipopolissacarídeos/metabolismo , Peptidoglicano/metabolismo , Peptidil Transferases/química , Peptidil Transferases/genética , Periplasma/enzimologia , Periplasma/genética , Periplasma/metabolismo , Transporte Proteico , Rhizobiaceae/química , Rhizobiaceae/genética
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