Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.960
Filtrar
Mais filtros

Coleção SES
Intervalo de ano de publicação
1.
Nucleic Acids Res ; 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38943343

RESUMO

Polyadenylation controls mRNA biogenesis, nucleo-cytoplasmic export, translation and decay. These processes are interdependent and coordinately regulated by poly(A)-binding proteins (PABPs), yet how PABPs are themselves regulated is not fully understood. Here, we report the discovery that human nuclear PABPN1 is phosphorylated by mitotic kinases at four specific sites during mitosis, a time when nucleoplasm and cytoplasm mix. To understand the functional consequences of phosphorylation, we generated a panel of stable cell lines inducibly over-expressing PABPN1 with point mutations at these sites. Phospho-inhibitory mutations decreased cell proliferation, highlighting the importance of PABPN1 phosphorylation in cycling cells. Dynamic regulation of poly(A) tail length and RNA stability have emerged as important modes of gene regulation. We therefore employed long-read sequencing to determine how PABPN1 phospho-site mutants affected poly(A) tails lengths and TimeLapse-seq to monitor mRNA synthesis and decay. Widespread poly(A) tail lengthening was observed for phospho-inhibitory PABPN1 mutants. In contrast, expression of phospho-mimetic PABPN1 resulted in shorter poly(A) tails with increased non-A nucleotides, in addition to increased transcription and reduced stability of a distinct cohort of mRNAs. Taken together, PABPN1 phosphorylation remodels poly(A) tails and increases mRNA turnover, supporting the model that enhanced transcriptome dynamics reset gene expression programs across the cell cycle.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38881423

RESUMO

Aqueous humor drainage from the anterior eye determines intraocular pressure (IOP) under homeostatic and pathological conditions. Swelling of the trabecular meshwork (TM) alters its flow resistance but the mechanisms that sense and transduce osmotic gradients remain poorly understood. We investigated TM osmotransduction and its role in calcium and chloride homeostasis using molecular analyses, optical imaging and electrophysiology. Anisosmotic conditions elicited proportional changes in TM cell volume, with swelling, but not shrinking, evoking elevations in intracellular calcium concentration [Ca2+]TM. Hypotonicity-evoked calcium signals were sensitive to HC067047, a selective blocker of TRPV4 channels, whereas the agonist GSK1016790A promoted swelling under isotonic conditions. TRPV4 inhibition partially suppressed hypotonicity-induced volume increases and reduced the magnitude of the swelling-induced membrane current, with a substantial fraction of the swelling-evoked current abrogated by Cl- channel antagonists DIDS and niflumic acid. The transcriptome of volume-sensing chloride channel candidates in primary human was dominated by ANO6 transcripts, with moderate expression of ANO3, ANO7, ANO10 transcripts and low expression of LTTRC genes that encode constituents of the volume-activated anion channel. Imposition of 190 mOsm but not 285 mOsm hypotonic gradients increased conventional outflow in mouse eyes. TRPV4-mediated cation influx thus works with Cl- efflux to sense and respond to osmotic stress, potentially contributing to pathological swelling, calcium overload and intracellular signaling that could exacerbate functional disturbances in inflammatory disease and glaucoma.

3.
Nature ; 564(7736): 405-409, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30510161

RESUMO

The formation, storage and chemical differentiation of magma in the Earth's crust is of fundamental importance in igneous geology and volcanology. Recent data are challenging the high-melt-fraction 'magma chamber' paradigm that has underpinned models of crustal magmatism for over a century, suggesting instead that magma is normally stored in low-melt-fraction 'mush reservoirs'1-9. A mush reservoir comprises a porous and permeable framework of closely packed crystals with melt present in the pore space1,10. However, many common features of crustal magmatism have not yet been explained by either the 'chamber' or 'mush reservoir' concepts1,11. Here we show that reactive melt flow is a critical, but hitherto neglected, process in crustal mush reservoirs, caused by buoyant melt percolating upwards through, and reacting with, the crystals10. Reactive melt flow in mush reservoirs produces the low-crystallinity, chemically differentiated (silicic) magmas that ascend to form shallower intrusions or erupt to the surface11-13. These magmas can host much older crystals, stored at low and even sub-solidus temperatures, consistent with crystal chemistry data6-9. Changes in local bulk composition caused by reactive melt flow, rather than large increases in temperature, produce the rapid increase in melt fraction that remobilizes these cool- or cold-stored crystals. Reactive flow can also produce bimodality in magma compositions sourced from mid- to lower-crustal reservoirs14,15. Trace-element profiles generated by reactive flow are similar to those observed in a well studied reservoir now exposed at the surface16. We propose that magma storage and differentiation primarily occurs by reactive melt flow in long-lived mush reservoirs, rather than by the commonly invoked process of fractional crystallization in magma chambers14.

4.
Arch Microbiol ; 205(12): 368, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37923857

RESUMO

A novel sulfate-reducing bacterium (strain 12FAKT) was isolated from sediment sampled from a brackish lake in Japan. Respiratory growth was observed with formate and pyruvate as an electron donor. Sulfate, thiosulfate, elemental sulfur and dimethyl sulfoxide were utilized as an electron acceptor. The isolate grew over a temperature range of 18-42 °C (optimum 35-37 °C), a NaCl concentration range of 50-450 mM (optimum 150-300 mM) and a pH range of 6.6-7.5. The 12FAKT genome consists of a circular chromosome with a length of 4.5 Mbp and G + C content of 63.6%. Based on 16S rRNA gene sequence similarity, the closest cultured relative was Desulfarculus baarsii 2st14T (92.2%). Genome-based phylogenetic analysis placed strain 12FAKT within the family Desulfarculaceae but did not affiliate the strain with any existing genus. Taken together, we propose a novel species of a novel genus, Desulfoferula mesophilus gen. nov. sp. nov. with the type strain 12FAKT (= DSM 115219T = JCM 39399T).


Assuntos
Lagos , Sulfatos , RNA Ribossômico 16S/genética , Filogenia , Técnicas de Tipagem Bacteriana , Bactérias/genética , DNA Bacteriano/genética , DNA Bacteriano/química , Análise de Sequência de DNA
5.
PLoS Comput Biol ; 18(1): e1009155, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35041651

RESUMO

We introduce a framework for end-to-end integrative modeling of 3D single-cell multi-channel fluorescent image data of diverse subcellular structures. We employ stacked conditional ß-variational autoencoders to first learn a latent representation of cell morphology, and then learn a latent representation of subcellular structure localization which is conditioned on the learned cell morphology. Our model is flexible and can be trained on images of arbitrary subcellular structures and at varying degrees of sparsity and reconstruction fidelity. We train our full model on 3D cell image data and explore design trade-offs in the 2D setting. Once trained, our model can be used to predict plausible locations of structures in cells where these structures were not imaged. The trained model can also be used to quantify the variation in the location of subcellular structures by generating plausible instantiations of each structure in arbitrary cell geometries. We apply our trained model to a small drug perturbation screen to demonstrate its applicability to new data. We show how the latent representations of drugged cells differ from unperturbed cells as expected by on-target effects of the drugs.


Assuntos
Núcleo Celular/fisiologia , Forma Celular/fisiologia , Células-Tronco Pluripotentes Induzidas/citologia , Espaço Intracelular , Modelos Biológicos , Células Cultivadas , Biologia Computacional , Humanos , Imageamento Tridimensional , Espaço Intracelular/química , Espaço Intracelular/metabolismo , Espaço Intracelular/fisiologia , Microscopia de Fluorescência , Análise de Célula Única
6.
Malar J ; 22(1): 161, 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-37208735

RESUMO

BACKGROUND: The unmet demand for effective malaria transmission-blocking agents targeting the transmissible stages of Plasmodium necessitates intensive discovery efforts. In this study, a bioactive bisbenzylisoquinoline (BBIQ), isoliensinine, from Cissampelos pariera (Menispermaceae) rhizomes was identified and characterized for its anti-malarial activity. METHODS: Malaria SYBR Green I fluorescence assay was performed to evaluate the in vitro antimalarial activity against D6, Dd2, and F32-ART5 clones, and immediate ex vivo (IEV) susceptibility for 10 freshly collected P. falciparum isolates. To determine the speed- and stage-of-action of isoliensinine, an IC50 speed assay and morphological analyses were performed using synchronized Dd2 asexuals. Gametocytocidal activity against two culture-adapted gametocyte-producing clinical isolates was determined using microscopy readouts, with possible molecular targets and their binding affinities deduced in silico. RESULTS: Isoliensinine displayed a potent in vitro gametocytocidal activity at mean IC50gam values ranging between 0.41 and 0.69 µM for Plasmodium falciparum clinical isolates. The BBIQ compound also inhibited asexual replication at mean IC50Asexual of 2.17 µM, 2.22 µM, and 2.39 µM for D6, Dd2 and F32-ART5 respectively, targeting the late-trophozoite to schizont transition. Further characterization demonstrated a considerable immediate ex vivo potency against human clinical isolates at a geometric mean IC50IEV = 1.433 µM (95% CI 0.917-2.242). In silico analyses postulated a probable anti-malarial mechanism of action by high binding affinities for four mitotic division protein kinases; Pfnek1, Pfmap2, Pfclk1, and Pfclk4. Additionally, isoliensinine was predicted to possess an optimal pharmacokinetics profile and drug-likeness properties. CONCLUSION: These findings highlight considerable grounds for further exploration of isoliensinine as an amenable scaffold for malaria transmission-blocking chemistry and target validation.


Assuntos
Antimaláricos , Cissampelos , Malária Falciparum , Malária , Humanos , Antimaláricos/química , Plasmodium falciparum , Rizoma
7.
Nature ; 542(7641): 340-343, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28166539

RESUMO

Helium isotopes provide an important tool for tracing early-Earth, primordial reservoirs that have survived in the planet's interior. Volcanic hotspot lavas, like those erupted at Hawaii and Iceland, can host rare, high 3He/4He isotopic ratios (up to 50 times the present atmospheric ratio, Ra) compared to the lower 3He/4He ratios identified in mid-ocean-ridge basalts that form by melting the upper mantle (about 8Ra; ref. 5). A long-standing hypothesis maintains that the high-3He/4He domain resides in the deep mantle, beneath the upper mantle sampled by mid-ocean-ridge basalts, and that buoyantly upwelling plumes from the deep mantle transport high-3He/4He material to the shallow mantle beneath plume-fed hotspots. One problem with this hypothesis is that, while some hotspots have 3He/4He values ranging from low to high, other hotspots exhibit only low 3He/4He ratios. Here we show that, among hotspots suggested to overlie mantle plumes, those with the highest maximum 3He/4He ratios have high hotspot buoyancy fluxes and overlie regions with seismic low-velocity anomalies in the upper mantle, unlike plume-fed hotspots with only low maximum 3He/4He ratios. We interpret the relationships between 3He/4He values, hotspot buoyancy flux, and upper-mantle shear wave velocity to mean that hot plumes-which exhibit seismic low-velocity anomalies at depths of 200 kilometres-are more buoyant and entrain both high-3He/4He and low-3He/4He material. In contrast, cooler, less buoyant plumes do not entrain this high-3He/4He material. This can be explained if the high-3He/4He domain is denser than low-3He/4He mantle components hosted in plumes, and if high-3He/4He material is entrained from the deep mantle only by the hottest, most buoyant plumes. Such a dense, deep-mantle high-3He/4He domain could remain isolated from the convecting mantle, which may help to explain the preservation of early Hadean (>4.5 billion years ago) geochemical anomalies in lavas sampling this reservoir.

8.
Arch Phys Med Rehabil ; 104(6): 918-924, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36758714

RESUMO

OBJECTIVES: To (1) describe characteristics of children with anoxic or hypoxic brain injuries (AnHBI) who presented to an inpatient rehabilitation unit, (2) explore functional outcomes of children with AnHBI at discharge, and (3) examine differences between children with AnHBI associated with cardiac arrest (CA) vs those with respiratory arrest (RA) only. DESIGN: Retrospective cohort study. SETTING: Pediatric inpatient rehabilitation hospital in the Northeast United States. PARTICIPANTS: A total of 46 children and adolescents ages 11 months to 18 years admitted to an inpatient rehabilitation brain injury unit (1994-2018) for a first inpatient admission after AnHBI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pediatric Cerebral Performance Category Scale (PCPC), Pediatric Overall Performance Category, and Functional Independence Measure for Children developmental functional quotients (WeeFIM DFQs) total and subscale scores. RESULTS: Most children had no disability before injury (PCPC=normal, n=37/46) and displayed significant functional impairments at admission to inpatient rehabilitation (PCPC=normal/mild, n=1/46). WeeFIM and PCPC scores improved significantly during inpatient rehabilitation (WeeFIM DFQ Total, P=.003; PCPC, P<.001), although many children continued to demonstrate significant impairments at discharge (PCPC=normal/mild, n=5/46). Functioning was better for the RA-only group relative to the CA group at admission (WeeFIM DFQ Total, P=.006) and discharge (WeeFIM DFQ Total, P<.001). Ongoing gains in functioning were noted 3 months after discharge compared with discharge (WeeFIM DFQ Cognitive, P=.008). CONCLUSIONS: In this group of children with AnHBI who received inpatient rehabilitation, functional status improves significantly between rehabilitation admission and discharge. By discharge, many children continued to display significant impairments, a minority of children had favorable neurologic outcomes, and children with CA have worse outcomes than those with RA-only. Given the small sample size, future research should examine functional recovery during inpatient rehabilitation in a larger, multisite cohort and include longer-term follow-up to examine recovery patterns over time.


Assuntos
Lesões Encefálicas , Pacientes Internados , Adolescente , Criança , Humanos , Estudos Retrospectivos , Recuperação de Função Fisiológica , Hospitalização , Lesões Encefálicas/reabilitação
9.
J Interv Cardiol ; 2022: 9926423, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35832534

RESUMO

Objectives: This study was conducted to determine why heart teams recommended transcatheter aortic valve replacement (TAVR) versus surgical AVR (SAVR) for patients at low predicted risk of mortality (PROM) and describe outcomes of these cases. Background: Historically, referral to TAVR was based predominately on the Society of Thoracic Surgeons (STS) risk model's PROM >3%. In selected cases, heart teams had latitude to overrule these scores. The clinical reasons and outcomes for these cases are unclear. Methods: Retrospective data were gathered for all TAVR and SAVR cases conducted by 9 hospitals between 2013 and 2017. Results: Cases included TAVR patients with STS PROM >3% (n = 2,711) and ≤3% (n = 415) and SAVR with STS PROM ≤3% (n = 1,438). Leading reasons for recommending TAVR in the PROM ≤3% group were frailty (57%), hostile chest (22%), severe lung disease (16%), and morbid obesity (13%), and 44% of cases had multiple reasons. Most postoperative and 30-day outcomes were similar between TAVR groups, but the STS PROM ≤3% group had a one-day shorter length of stay (2.5 ± 3.4 vs. 3.5 ± 4.7 days; p ≤ 0.001) and higher one-year survival (91.6% vs. 86.0%, p=0.002). In patients with STS PROM ≤3%, 30-day mortality was higher for TAVR versus SAVR (2.0% vs. 0.6%; p < 0.001). Conclusions: Heart teams recommended TAVR in patients with STS PROM ≤3% primarily due to frailty, hostile chest, severe lung disease, and/or morbid obesity. Similar postoperative outcomes between these patients and those with STS PROM >3% suggest that decisions to overrule STS PROM ≤3% were merited and may have reduced SAVR 30-day mortality rate.


Assuntos
Estenose da Valva Aórtica , Fragilidade , Implante de Prótese de Valva Cardíaca , Pneumopatias , Obesidade Mórbida , Substituição da Valva Aórtica Transcateter , Valva Aórtica/cirurgia , Estenose da Valva Aórtica/cirurgia , Fragilidade/etiologia , Fragilidade/cirurgia , Implante de Prótese de Valva Cardíaca/efeitos adversos , Humanos , Pneumopatias/etiologia , Pneumopatias/cirurgia , Estudos Retrospectivos , Fatores de Risco , Substituição da Valva Aórtica Transcateter/efeitos adversos , Resultado do Tratamento
10.
Environ Sci Technol ; 56(20): 14840-14851, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36162065

RESUMO

Stable Fe isotopes have only recently been measured in freshwater systems, mainly in meromictic lakes. Here we report the δ56Fe of dissolved, particulate, and sediment Fe in two small dimictic boreal shield headwater lakes: manipulated eutrophic Lake 227, with annual cyanobacterial blooms, and unmanipulated oligotrophic Lake 442. Within the lakes, the range in δ56Fe is large (ca. -0.9 to +1.8‰), spanning more than half the entire range of natural Earth surface samples. Two layers in the water column with distinctive δ56Fe of dissolved (dis) and particulate (spm) Fe were observed, despite differences in trophic states. In the epilimnia of both lakes, a large Δ56Fedis-spm fractionation of 0.4-1‰ between dissolved and particulate Fe was only observed during cyanobacterial blooms in Lake 227, possibly regulated by selective biological uptake of isotopically light Fe by cyanobacteria. In the anoxic layers in both lakes, upward flux from sediments dominates the dissolved Fe pool with an apparent Δ56Fedis-spm fractionation of -2.2 to -0.6‰. Large Δ56Fedis-spm and previously published metagenome sequence data suggest active Fe cycling processes in anoxic layers, such as microaerophilic Fe(II) oxidation or photoferrotrophy, could regulate biogeochemical cycling. Large fractionation of stable Fe isotopes in these lakes provides a potential tool to probe Fe cycling and the acquisition of Fe by cyanobacteria, with relevance for understanding biogeochemical cycling of Earth's early ferruginous oceans.


Assuntos
Cianobactérias , Lagos , Compostos Ferrosos , Sedimentos Geológicos/microbiologia , Ferro , Isótopos de Ferro , Lagos/microbiologia , Redes e Vias Metabólicas , Minerais , Água
11.
Int J Mol Sci ; 23(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36498868

RESUMO

Cannabis sativa (Cannabis) has recently been legalized in multiple countries globally for either its recreational or medicinal use. This, in turn, has led to a marked increase in the number of Cannabis varieties available for use in either market. However, little information currently exists on the genetic distinction between adopted varieties. Such fundamental knowledge is of considerable value and underpins the accelerated development of both a nascent pharmaceutical industry and the commercial recreational market. Therefore, in this study, we sought to assess genetic diversity across 10 Cannabis varieties by undertaking a reduced representation shotgun sequencing approach on 83 individual plants to identify variations which could be used to resolve the genetic structure of the assessed population. Such an approach also allowed for the identification of the genetic features putatively associated with the production of secondary metabolites in Cannabis. Initial analysis identified 3608 variants across the assessed population with phylogenetic analysis of this data subsequently enabling the confident grouping of each variety into distinct subpopulations. Within our dataset, the most diagnostically informative single nucleotide polymorphisms (SNPs) were determined to be associated with the long-terminal repeat (LTRs) class of retroelements, with 172 such SNPs used to fully resolve the genetic structure of the assessed population. These 172 SNPs could be used to design a targeted resequencing panel, which we propose could be used to rapidly screen different Cannabis plants to determine genetic relationships, as well as to provide a more robust, scientific classification of Cannabis varieties as the field moves into the pharmaceutical sphere.


Assuntos
Cannabis , Alucinógenos , Cannabis/genética , Cannabis/química , Filogenia , Sequências Repetidas Terminais , Análise de Sequência de DNA , Polimorfismo de Nucleotídeo Único , Agonistas de Receptores de Canabinoides , Variação Genética
12.
Dev Dyn ; 250(6): 866-879, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33587313

RESUMO

BACKGROUND: Ambystoma mexicanum, the axolotl salamander, is a classic model organism used to study vertebrate regeneration. It is assumed that axolotls regenerate most tissues, but the exploration of lung regeneration has not been performed until now. RESULTS: Unlike the blastema-based response used during appendage regeneration, lung amputation led to organ-wide proliferation. Pneumocytes and mesenchymal cells responded to injury by increased proliferation throughout the injured lung, which led to a recovery in lung mass and morphology by 56 days post-amputation. Receptors associated with the Neuregulin signaling pathway were upregulated at one and 3 weeks post lung amputation. We show expression of the ligand, neuregulin, in the I/X cranial nerve that innervates the lung and cells within the lung. Supplemental administration of Neuregulin peptide induced widespread proliferation in the lung similar to an injury response, suggesting that neuregulin signaling may play a significant role during lung regeneration. CONCLUSION: Our study characterizes axolotl lung regeneration. We show that the lung responds to injury by an organ-wide proliferative response of multiple cell types, including pneumocytes, to recover lung mass.


Assuntos
Ambystoma mexicanum/fisiologia , Proliferação de Células/fisiologia , Lesão Pulmonar/fisiopatologia , Pulmão/fisiologia , Regeneração/fisiologia , Animais , Pulmão/metabolismo , Lesão Pulmonar/metabolismo , Neurregulinas/metabolismo , Transdução de Sinais/fisiologia , Regulação para Cima
13.
Scand J Psychol ; 63(1): 32-38, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34524693

RESUMO

Loneliness is a significant health concern that may be influenced by dispositional features. Pathological narcissism may elevate loneliness through aversive interpersonal behaviors and negative social appraisals. The present study examined two dimensions of pathological narcissism, along with five-factor personality traits, in relation to loneliness among 120 young adults. Loneliness was also examined as a mediator between pathological narcissism and satisfaction with life. Narcissistic grandiosity and narcissistic vulnerability were both significantly associated with loneliness. Multiple regression analysis, including five-factor traits, revealed narcissistic vulnerability to be uniquely associated with loneliness, along with neuroticism. Mediation analysis also found an indirect effect of narcissistic vulnerability on reduced satisfaction with life, through loneliness as a mediator. These preliminary findings point to future research needs and potential clinical consideration of narcissistic vulnerability as a dispositional risk factor for loneliness.


Assuntos
Solidão , Narcisismo , Humanos , Satisfação Pessoal , Personalidade , Transtornos da Personalidade , Adulto Jovem
14.
Acute Med ; 21(2): 104-106, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35681184

RESUMO

A 39-year-old man presented to the Emergency Department following a sudden onset of palpitations an hour earlier. He was clammy and felt generally unwell. He was normally fit and active with no history of cardiac symptoms including palpitations - he mentioned as a teenager he was told that he had an 'extra bit of wiring in his heart' but nothing further was done. His only regular medication was Sertraline. He drank alcohol to excess. On examination, he was hypotensive but pain free. Bloods including potassium and magnesium were within normal limits - venous lactate was mildly elevated at 2.8.


Assuntos
Choque , Adolescente , Adulto , Humanos , Masculino
15.
J Physiol ; 599(2): 571-592, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33226641

RESUMO

KEY POINTS: Trabecular meshwork (TM) is a highly mechanosensitive tissue in the eye that regulates intraocular pressure through the control of aqueous humour drainage. Its dysfunction underlies the progression of glaucoma but neither the mechanisms through which TM cells sense pressure nor their role in aqueous humour outflow are understood at the molecular level. We identified the Piezo1 channel as a key TM transducer of tensile stretch, shear flow and pressure. Its activation resulted in intracellular signals that altered organization of the cytoskeleton and cell-extracellular matrix contacts and modulated the trabecular component of aqueous outflow whereas another channel, TRPV4, mediated a delayed mechanoresponse. This study helps elucidate basic mechanotransduction properties that may contribute to intraocular pressure regulation in the vertebrate eye. ABSTRACT: Chronic elevations in intraocular pressure (IOP) can cause blindness by compromising the function of trabecular meshwork (TM) cells in the anterior eye, but how these cells sense and transduce pressure stimuli is poorly understood. Here, we demonstrate functional expression of two mechanically activated channels in human TM cells. Pressure-induced cell stretch evoked a rapid increase in transmembrane current that was inhibited by antagonists of the mechanogated channel Piezo1, Ruthenium Red and GsMTx4, and attenuated in Piezo1-deficient cells. The majority of TM cells exhibited a delayed stretch-activated current that was mediated independently of Piezo1 by TRPV4 (transient receptor potential cation channel, subfamily V, member 4) channels. Piezo1 functions as the principal TM transducer of physiological levels of shear stress, with both shear and the Piezo1 agonist Yoda1 increasing the number of focal cell-matrix contacts. Analysis of TM-dependent fluid drainage from the anterior eye showed significant inhibition by GsMTx4. Collectively, these results suggest that TM mechanosensitivity utilizes kinetically, regulatory and functionally distinct pressure transducers to inform the cells about force-sensing contexts. Piezo1-dependent control of shear flow sensing, calcium homeostasis, cytoskeletal dynamics and pressure-dependent outflow suggests potential for a novel therapeutic target in treating glaucoma.


Assuntos
Humor Aquoso , Malha Trabecular , Citoesqueleto , Humanos , Pressão Intraocular , Canais Iônicos/genética , Mecanotransdução Celular , Canais de Cátion TRPV
16.
RNA ; 25(5): 539-556, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30770398

RESUMO

The interferon-inducible protein kinase R (PKR) is a key component of host innate immunity that restricts viral replication and propagation. As one of the four eIF2α kinases that sense diverse stresses and direct the integrated stress response (ISR) crucial for cell survival and proliferation, PKR's versatile roles extend well beyond antiviral defense. Targeted by numerous host and viral regulators made of RNA and proteins, PKR is subject to multiple layers of endogenous control and external manipulation, driving its rapid evolution. These versatile regulators include not only the canonical double-stranded RNA (dsRNA) that activates the kinase activity of PKR, but also highly structured viral, host, and artificial RNAs that exert a full spectrum of effects. In this review, we discuss our deepening understanding of the allosteric mechanism that connects the regulatory and effector domains of PKR, with an emphasis on diverse structured RNA regulators in comparison to their protein counterparts. Through this analysis, we conclude that much of the mechanistic details that underlie this RNA-regulated kinase await structural and functional elucidation, upon which we can then describe a "PKR code," a set of structural and chemical features of RNA that are both descriptive and predictive for their effects on PKR.


Assuntos
Interações Hospedeiro-Patógeno/genética , RNA de Cadeia Dupla/genética , RNA não Traduzido/genética , Viroses/genética , eIF-2 Quinase/genética , Regulação Alostérica , Animais , Sequência de Bases , Sítios de Ligação , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade Inata , Interferons/genética , Interferons/imunologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , RNA de Cadeia Dupla/química , RNA de Cadeia Dupla/imunologia , RNA não Traduzido/química , RNA não Traduzido/imunologia , Viroses/imunologia , Viroses/virologia , Replicação Viral , eIF-2 Quinase/química , eIF-2 Quinase/imunologia
17.
BMC Microbiol ; 21(1): 113, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33858327

RESUMO

BACKGROUND: Emerging evidence implicates the gut microbiome in liver inflammation and hepatocellular carcinoma (HCC) development. We aimed to characterize the temporal evolution of gut dysbiosis, in relation to the phenotype of systemic and hepatic inflammatory responses leading to HCC development. In the present study, Mdr2 -/- mice were used as a model of inflammation-based HCC. Gut microbiome composition and function, in addition to serum LPS, serum cytokines/chemokines and intrahepatic inflammatory genes were measured throughout the course of liver injury until HCC development. RESULTS: Early stages of liver injury, inflammation and cirrhosis, were characterized by dysbiosis. Microbiome functional pathways pertaining to gut barrier dysfunction were enriched during the initial phase of liver inflammation and cirrhosis, whilst those supporting lipopolysaccharide (LPS) biosynthesis increased as cirrhosis and HCC ensued. In parallel, serum LPS progressively increased during the course of liver injury, corresponding to a shift towards a systemic Th1/Th17 proinflammatory phenotype. Alongside, the intrahepatic inflammatory gene profile transitioned from a proinflammatory phenotype in the initial phases of liver injury to an immunosuppressed one in HCC. In established HCC, a switch in microbiome function from carbohydrate to amino acid metabolism occurred. CONCLUSION: In Mdr2 -/- mice, dysbiosis precedes HCC development, with temporal evolution of microbiome function to support gut barrier dysfunction, LPS biosynthesis, and redirection of energy source utilization. A corresponding shift in systemic and intrahepatic inflammatory responses occurred supporting HCC development. These findings support the notion that gut based therapeutic interventions could be beneficial early in the course of liver disease to halt HCC development.


Assuntos
Carcinoma Hepatocelular/complicações , Carcinoma Hepatocelular/microbiologia , Disbiose/complicações , Disbiose/imunologia , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/microbiologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Animais , Carcinoma Hepatocelular/imunologia , Modelos Animais de Doenças , Disbiose/microbiologia , Microbioma Gastrointestinal/fisiologia , Inflamação/complicações , Inflamação/microbiologia , Neoplasias Hepáticas/imunologia , Camundongos , Tempo , Membro 4 da Subfamília B de Transportadores de Cassetes de Ligação de ATP
18.
Public Health Nutr ; 24(17): 5756-5768, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33541468

RESUMO

OBJECTIVE: To evaluate age-related differences in the independent/combined association of added sugar intake from soda and body adiposity with hyperuricaemia in gender-stratified US adults. DESIGN: Consumption of added sugar from soda was calculated from 24-h dietary interviews and categorised into none, regular and excessive consumption. Hyperuricaemia was defined as serum uric acid levels >417 mmol/l in men and >357 mmol/l in women. Multiple regression models with interaction terms and logistic models adjusted for covariates were conducted under survey-data modules. SETTING: National Health and Nutrition Examination Survey during 2007-2016. PARTICIPANTS: 15 338 adults without gout, failing kidneys, an estimated glomerular filtration rate < 30 or diabetes were selected. RESULTS: The age-stratified prevalence rate of hyperuricaemia was 18·8-20·4 % in males and 6·8-17·3 % in females. Hyperuricaemia prevalence of approximately 50 % was observed in young and middle age males who consumed excessive added sugar from soda. Excessive added sugar intake was observed to be associated with 1·5- to 2·0-fold and 2·0- to 2·3-fold increased risk of the probability of hyperuricaemia in young and middle age males and middle age females, respectively. Study participants, regardless of age or gender, who were obese and consumed excessive added sugar from soda had the highest risk of having hyperuricaemia. CONCLUSIONS: Our study revealed that the association between hyperuricaemia and consumption of excessive added sugar from soda may vary by age and gender. Obese adults who consumed excessive added sugar from soda had the highest risk of hyperuricaemia, a finding that was found across all age-specific groups for both genders.


Assuntos
Hiperuricemia , Adiposidade , Adulto , Bebidas Gaseificadas/efeitos adversos , Feminino , Humanos , Hiperuricemia/epidemiologia , Hiperuricemia/etiologia , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Obesidade/epidemiologia , Obesidade/etiologia , Ácido Úrico
19.
J Neuroophthalmol ; 41(3): 356-361, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415269

RESUMO

BACKGROUND: The novel coronavirus 2019 (COVID-19) pandemic has transformed health care. With the need to limit COVID-19 exposures, telemedicine has become an increasingly important format for clinical care. Compared with other fields, neuro-ophthalmology faces unique challenges, given its dependence on physical examination signs that are difficult to elicit outside the office setting. As such, it is imperative to understand both patient and provider experiences to continue to adapt the technology and tailor its application. The purpose of this study is to analyze both neuro-ophthalmology physician and patient satisfaction with virtual health visits during the time of the COVID-19 pandemic. METHODS: Across three institutions (NYU Langone Health, Indiana University Health, and Columbia University Medical Center), telemedicine surveys were administered to 159 patients. Neuro-ophthalmologists completed 157 surveys; each of these were linked to a single patient visit. Patient surveys consisted of 5 questions regarding visit preparation, satisfaction, challenges, and comfort. The physician survey included 4 questions that focused on ability to gather specific clinical information by history and examination. RESULTS: Among 159 patients, 104 (65.4%) reported that they were satisfied with the visit, and 149 (93.7%) indicated that they were comfortable asking questions. Sixty-eight (73.9%) patients found the instructions provided before the visit easy to understand. Potential areas for improvement noted by patients included more detailed preparation instructions and better technology (phone positioning, Internet connection, and software). More than 87% (137/157) of neuro-ophthalmologists surveyed reported having performed an examination that provided enough information for medical decision-making. Some areas of the neuro-ophthalmologic examination were reported to be easy to conduct (range of eye movements, visual acuity, Amsler grids, Ishihara color plates, and pupillary examination). Other components were more difficult (saccades, red desaturation, visual fields, convergence, oscillations, ocular alignment, and smooth pursuit); some were especially challenging (vestibulo-ocular reflex [VOR], VOR suppression, and optokinetic nystagmus). Clinicians noted that virtual health visits were limited by patient preparation, inability to perform certain parts of the examination (funduscopy and pupils), and technological issues. CONCLUSIONS: Among virtual neuro-ophthalmology visits evaluated, most offer patients with appointments that satisfy their needs. Most physicians in this cohort obtained adequate clinical information for decision-making. Even better technology and instructions may help improve aspects of virtual health visits.


Assuntos
COVID-19/epidemiologia , Oftalmopatias/diagnóstico , Oftalmologia/métodos , Pandemias , Médicos/estatística & dados numéricos , Inquéritos e Questionários , Telemedicina/métodos , Comorbidade , Oftalmopatias/epidemiologia , Humanos , Estudos Retrospectivos
20.
Pestic Biochem Physiol ; 178: 104912, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446188

RESUMO

Intracellular effects exerted by phytochemicals eliciting insect growth-retarding responses during vector control intervention remain largely underexplored. We studied the effects of Zanthoxylum chalybeum Engl. (Rutaceae) (ZCE) root derivatives against malaria (Anopheles gambiae) and arbovirus vector (Aedes aegypti) larvae to decipher possible molecular targets. We report dose-dependent biphasic effects on larval response, with transient exposure to ZCE and its bioactive fraction (ZCFr.5) inhibiting acetylcholinesterase (AChE) activity, inducing larval lethality and growth retardation at sublethal doses. Half-maximal lethal concentrations (LC50) for ZCE against An. gambiae and Ae. aegypti larvae after 24-h exposure were 9.00 ppm and 12.26 ppm, respectively. The active fraction ZCFr.5 exerted LC50 of 1.58 ppm and 3.21 ppm for An. gambiae and Ae. aegypti larvae, respectively. Inhibition of AChE was potentially linked to larval toxicity afforded by 2-tridecanone, palmitic acid (hexadecanoic acid), linoleic acid ((Z,Z)-9,12-octadecadienoic acid), sesamin, ß-caryophyllene among other compounds identified in the bioactive fraction. In addition, the phenotypic larval retardation induced by ZCE root constituents was exerted through transcriptional modulation of ecdysteroidogenic CYP450 genes. Collectively, these findings provide an explorative avenue for developing potential mosquito control agents from Z. chalybeum root constituents.


Assuntos
Aedes , Culex , Inseticidas , Zanthoxylum , Animais , Transtornos do Crescimento , Inseticidas/toxicidade , Larva , Controle de Mosquitos , Mosquitos Vetores , Extratos Vegetais
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa