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1.
Cell ; 186(25): 5438-5439, 2023 12 07.
Artículo en Inglés | MEDLINE | ID: mdl-38065077

RESUMEN

An Arabidopsis cell-surface auxin receptor that mediates rapid elongation consists of transmembrane kinases (TMKs) and an auxin-binding co-receptor. Auxin-binding protein 1 (ABP1) is one identified TMK co-receptor, but abp1 mutants have no elongation phenotypes. Yu et al. use structural analysis of the ABP1-binding pocket to identify functional ABP1-like (ABL) TMK co-receptors that regulate rapid growth.


Asunto(s)
Arabidopsis , Ácidos Indolacéticos , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/metabolismo , Arabidopsis/metabolismo , Proteínas Portadoras/metabolismo , Transducción de Señal
2.
Cell ; 156(5): 1084-95, 2014 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-24581502

RESUMEN

Cells continuously adjust their behavior in response to changing environmental conditions. Both intensity and duration of external signals are critical factors in determining what response is initiated. To understand how intracellular signaling networks process such multidimensional information, we studied the AtRGS1-mediated glucose response system of Arabidopsis. By combining experiments with mathematical modeling, we discovered a reciprocal dose and duration response relying on the orchestrated action of three kinases (AtWNK1, AtWNK8, and AtWNK10) acting on distinct timescales and activation thresholds. Specifically, we find that high concentrations of D-glucose rapidly signal through AtWNK8 and AtWNK10, whereas low, sustained sugar concentration slowly activate the pathway through AtWNK1, allowing the cells to respond similarly to transient, high-intensity signals and sustained, low-intensity signals. This "dose-duration reciprocity" allows encoding of both the intensity and persistence of glucose as an important energy resource and signaling molecule.


Asunto(s)
Arabidopsis/metabolismo , Glucosa/metabolismo , Células Vegetales/metabolismo , Arabidopsis/citología , Proteínas de Arabidopsis/metabolismo , Endocitosis , Cinética , Modelos Biológicos , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas RGS/metabolismo , Factores de Tiempo , Proteína Quinasa Deficiente en Lisina WNK 1
3.
N Engl J Med ; 388(6): 499-510, 2023 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-36688507

RESUMEN

BACKGROUND: Intravenous fluids and vasopressor agents are commonly used in early resuscitation of patients with sepsis, but comparative data for prioritizing their delivery are limited. METHODS: In an unblinded superiority trial conducted at 60 U.S. centers, we randomly assigned patients to either a restrictive fluid strategy (prioritizing vasopressors and lower intravenous fluid volumes) or a liberal fluid strategy (prioritizing higher volumes of intravenous fluids before vasopressor use) for a 24-hour period. Randomization occurred within 4 hours after a patient met the criteria for sepsis-induced hypotension refractory to initial treatment with 1 to 3 liters of intravenous fluid. We hypothesized that all-cause mortality before discharge home by day 90 (primary outcome) would be lower with a restrictive fluid strategy than with a liberal fluid strategy. Safety was also assessed. RESULTS: A total of 1563 patients were enrolled, with 782 assigned to the restrictive fluid group and 781 to the liberal fluid group. Resuscitation therapies that were administered during the 24-hour protocol period differed between the two groups; less intravenous fluid was administered in the restrictive fluid group than in the liberal fluid group (difference of medians, -2134 ml; 95% confidence interval [CI], -2318 to -1949), whereas the restrictive fluid group had earlier, more prevalent, and longer duration of vasopressor use. Death from any cause before discharge home by day 90 occurred in 109 patients (14.0%) in the restrictive fluid group and in 116 patients (14.9%) in the liberal fluid group (estimated difference, -0.9 percentage points; 95% CI, -4.4 to 2.6; P = 0.61); 5 patients in the restrictive fluid group and 4 patients in the liberal fluid group had their data censored (lost to follow-up). The number of reported serious adverse events was similar in the two groups. CONCLUSIONS: Among patients with sepsis-induced hypotension, the restrictive fluid strategy that was used in this trial did not result in significantly lower (or higher) mortality before discharge home by day 90 than the liberal fluid strategy. (Funded by the National Heart, Lung, and Blood Institute; CLOVERS ClinicalTrials.gov number, NCT03434028.).


Asunto(s)
Fluidoterapia , Hipotensión , Sepsis , Humanos , Fluidoterapia/efectos adversos , Fluidoterapia/métodos , Fluidoterapia/mortalidad , Sepsis/complicaciones , Sepsis/mortalidad , Sepsis/terapia , Hipotensión/etiología , Hipotensión/mortalidad , Hipotensión/terapia , Factores de Tiempo , Resultado del Tratamiento , Vasoconstrictores/administración & dosificación , Vasoconstrictores/efectos adversos , Vasoconstrictores/uso terapéutico
4.
Mol Cell Proteomics ; 23(2): 100705, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38135118

RESUMEN

The microbe-associated molecular pattern flg22 is recognized in a flagellin-sensitive 2-dependent manner in root tip cells. Here, we show a rapid and massive change in protein abundance and phosphorylation state of the Arabidopsis root cell proteome in WT and a mutant deficient in heterotrimeric G-protein-coupled signaling. flg22-induced changes fall on proteins comprising a subset of this proteome, the heterotrimeric G protein interactome, and on highly-populated hubs of the immunity network. Approximately 95% of the phosphorylation changes in the heterotrimeric G-protein interactome depend, at least partially, on a functional G protein complex. One member of this interactome is ATBα, a substrate-recognition subunit of a protein phosphatase 2A complex and an interactor to Arabidopsis thaliana Regulator of G Signaling 1 protein (AtRGS1), a flg22-phosphorylated, 7-transmembrane spanning modulator of the nucleotide-binding state of the core G-protein complex. A null mutation of ATBα strongly increases basal endocytosis of AtRGS1. AtRGS1 steady-state protein level is lower in the atbα mutant in a proteasome-dependent manner. We propose that phosphorylation-dependent endocytosis of AtRGS1 is part of the mechanism to degrade AtRGS1, thus sustaining activation of the heterotrimeric G protein complex required for the regulation of system dynamics in innate immunity. The PP2A(ATBα) complex is a critical regulator of this signaling pathway.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Unión al GTP Heterotriméricas , Proteínas RGS , Arabidopsis/metabolismo , Fosforilación , Proteínas de Arabidopsis/metabolismo , Proteoma/metabolismo , Proteínas RGS/química , Proteínas RGS/genética , Proteínas RGS/metabolismo , Transducción de Señal , Proteínas de Unión al GTP Heterotriméricas/metabolismo , Flagelina/farmacología , Flagelina/metabolismo , Monoéster Fosfórico Hidrolasas/metabolismo
5.
Artículo en Inglés | MEDLINE | ID: mdl-39234690

RESUMEN

BACKGROUND: Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder. This study aimed to study the genotype distribution of FCS-causing genes in the United Kingdom, genotype-phenotype correlation, and clinical differences between FCS and multifactorial chylomicronemia syndrome (MCS). METHODS: The study included 154 patients (FCS, 74; MCS, 80) from the UK FCS national registry and the UK arm of the FCS International Quality Improvement and Service Evaluation Project. RESULTS: FCS was relatively common in non-Europeans and those with parental consanguinity (P<0.001 for both). LPL variants were more common in European patients with FCS (European, 64%; non-European, 46%), while the genotype was more diverse in non-European patients with FCS. Patients with FCS had a higher incidence compared with patients with MCS of acute pancreatitis (84% versus 60%; P=0.001), recurrent pancreatitis (92% versus 63%; P<0.001), unexplained abdominal pain (84% versus 52%; P<0.001), earlier age of onset (median [interquartile range]) of symptoms (15.0 [5.5-26.5] versus 34.0 [25.2-41.7] years; P<0.001), and of acute pancreatitis (24.0 [10.7-31.0] versus 33.5 [26.0-42.5] years; P<0.001). Adverse cardiometabolic features and their co-occurrence was more common in individuals with MCS compared with those with FCS (P<0.001 for each). Atherosclerotic cardiovascular disease was more prevalent in individuals with MCS than those with FCS (P=0.04). However, this association became nonsignificant after adjusting for age, sex, and body mass index. The prevalence of pancreatic complications and cardiometabolic profile of variant-positive MCS was intermediate between FCS and variant-negative MCS. CONCLUSIONS: The frequency of gene variant distribution varies based on the ethnic origin of patients with FCS. Patients with FCS are at a higher risk of pancreatic complications while the prevalence of atherosclerotic cardiovascular disease is lower in FCS compared with MCS. Carriers of heterozygous pathogenic variants have an intermediate phenotype between FCS and variant-negative MCS.

6.
Cell ; 143(1): 99-110, 2010 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-20887895

RESUMEN

Auxin is a multifunctional hormone essential for plant development and pattern formation. A nuclear auxin-signaling system controlling auxin-induced gene expression is well established, but cytoplasmic auxin signaling, as in its coordination of cell polarization, is unexplored. We found a cytoplasmic auxin-signaling mechanism that modulates the interdigitated growth of Arabidopsis leaf epidermal pavement cells (PCs), which develop interdigitated lobes and indentations to form a puzzle-piece shape in a two-dimensional plane. PC interdigitation is compromised in leaves deficient in either auxin biosynthesis or its export mediated by PINFORMED 1 localized at the lobe tip. Auxin coordinately activates two Rho GTPases, ROP2 and ROP6, which promote the formation of complementary lobes and indentations, respectively. Activation of these ROPs by auxin occurs within 30 s and depends on AUXIN-BINDING PROTEIN 1. These findings reveal Rho GTPase-based auxin-signaling mechanisms, which modulate the spatial coordination of cell expansion across a field of cells.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citología , Arabidopsis/metabolismo , Proteínas de Unión al GTP/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas de Unión al GTP Monoméricas/metabolismo , Transducción de Señal , Membrana Celular/metabolismo , Forma de la Célula , Hojas de la Planta/citología , Proteínas de Plantas/metabolismo , Receptores de Superficie Celular/metabolismo
7.
Cell ; 143(1): 111-21, 2010 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-20887896

RESUMEN

Spatial distribution of the plant hormone auxin regulates multiple aspects of plant development. These self-regulating auxin gradients are established by the action of PIN auxin transporters, whose activity is regulated by their constitutive cycling between the plasma membrane and endosomes. Here, we show that auxin signaling by the auxin receptor AUXIN-BINDING PROTEIN 1 (ABP1) inhibits the clathrin-mediated internalization of PIN proteins. ABP1 acts as a positive factor in clathrin recruitment to the plasma membrane, thereby promoting endocytosis. Auxin binding to ABP1 interferes with this action and leads to the inhibition of clathrin-mediated endocytosis. Our study demonstrates that ABP1 mediates a nontranscriptional auxin signaling that regulates the evolutionarily conserved process of clathrin-mediated endocytosis and suggests that this signaling may be essential for the developmentally important feedback of auxin on its own transport.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citología , Arabidopsis/metabolismo , Clatrina/metabolismo , Endocitosis , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/metabolismo , Receptores de Superficie Celular/metabolismo , Membrana Celular/metabolismo , Proteínas de Transporte de Membrana/metabolismo
8.
Genet Med ; 26(3): 101051, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38131308

RESUMEN

PURPOSE: The UK 100,000 Genomes Project offered participants screening for additional findings (AFs) in genes associated with familial hypercholesterolemia (FH) or hereditary cancer syndromes including breast/ovarian cancer (HBOC), Lynch, familial adenomatous polyposis, MYH-associated polyposis, multiple endocrine neoplasia (MEN), and von Hippel-Lindau. Here, we report disclosure processes, manifestation of AF-related disease, outcomes, and costs. METHODS: An observational study in an area representing one-fifth of England. RESULTS: Data were collected from 89 adult AF recipients. At disclosure, among 57 recipients of a cancer-predisposition-associated AF and 32 recipients of an FH-associated AF, 35% and 88%, respectively, had personal and/or family history evidence of AF-related disease. During post-disclosure investigations, 4 cancer-AF recipients had evidence of disease, including 1 medullary thyroid cancer. Six women with an HBOC AF, 3 women with a Lynch syndrome AF, and 2 individuals with a MEN AF elected for risk-reducing surgery. New hyperlipidemia diagnoses were made in 6 FH-AF recipients and treatment (re-)initiated for 7 with prior hyperlipidemia. Generating and disclosing AFs in this region cost £1.4m; £8680 per clinically significant AF. CONCLUSION: Generation and disclosure of AFs identifies individuals with and without personal or familial evidence of disease and prompts appropriate clinical interventions. Results can inform policy toward secondary findings.


Asunto(s)
Neoplasias de la Mama , Hiperlipidemias , Síndromes Neoplásicos Hereditarios , Adulto , Humanos , Femenino , Pruebas Genéticas/métodos , Revelación , Síndromes Neoplásicos Hereditarios/genética , Neoplasias de la Mama/genética , Hiperlipidemias/genética , Atención a la Salud , Predisposición Genética a la Enfermedad
9.
Plant Cell Environ ; 2024 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-38881245

RESUMEN

This study determines the functional role of the plant ultraviolet-B radiation (UV-B) photoreceptor, UV RESISTANCE LOCUS 8 (UVR8) under natural conditions using a large-scale 'synchronized-genetic-perturbation-field-experiment'. Laboratory experiments have demonstrated a role for UVR8 in UV-B responses but do not reflect the complexity of outdoor conditions where 'genotype × environment' interactions can mask laboratory-observed responses. Arabidopsis thaliana knockout mutant, uvr8-7, and the corresponding Wassilewskija wild type, were sown outdoors on the same date at 21 locations across Europe, ranging from 39°N to 67°N latitude. Growth and climatic data were monitored until bolting. At the onset of bolting, rosette size, dry weight, and phenolics and glucosinolates were quantified. The uvr8-7 mutant developed a larger rosette and contained less kaempferol glycosides, quercetin glycosides and hydroxycinnamic acid derivatives than the wild type across all locations, demonstrating a role for UVR8 under field conditions. UV effects on rosette size and kaempferol glycoside content were UVR8 dependent, but independent of latitude. In contrast, differences between wild type and uvr8-7 in total quercetin glycosides, and the quercetin-to-kaempferol ratio decreased with increasing latitude, that is, a more variable UV response. Thus, the large-scale synchronized approach applied demonstrates a location-dependent functional role of UVR8 under natural conditions.

10.
Inorg Chem ; 63(32): 14958-14968, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-39083592

RESUMEN

Ovarian cancer has the worst case-to-fatality ratio of all gynecologic malignancies. The main reasons for the high mortality rate are relapse and the development of chemoresistance. In this paper, the cytotoxic activity of two new multiaction platinum(IV) derivatives of cisplatin and oxaliplatin in a panel of ovarian cancer cells is reported. Cis,cis,trans-[Pt(NH3)2Cl2(IPA)(DCA)] (1) and trans-[Pt(DACH)(OX)(IPA)(DCA)] (2) (IPA = indole-3-propionic acid, DCA = dichloroacetate, DACH = 1R,2R-1,2-diaminocyclohexane, OX = oxalate) were synthesized and characterized by elemental analysis, ESI-MS, FT-IR, and 1H, 13C, and195Pt NMR spectroscopy. The biological activity was evaluated in A2780, PEA1, PEA2, SKOV3, SW626, and OVCAR3 cells. Both complexes are potent cytotoxins. Remarkably, complex 2 is 14 times more active in OVCAR3 cells than cisplatin and is able to overcome cisplatin resistance in PEA2 and A2780cis cells, which are models of post-treatment patient-developed and laboratory-induced resistance. This complex also shows activity in 3D cancer models of the A2780 cells. Mechanistic studies revealed that the complexes induce apoptosis via DNA damage and ROS generation.


Asunto(s)
Antineoplásicos , Apoptosis , Ensayos de Selección de Medicamentos Antitumorales , Neoplasias Ováricas , Humanos , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/patología , Femenino , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/síntesis química , Apoptosis/efectos de los fármacos , Complejos de Coordinación/farmacología , Complejos de Coordinación/química , Complejos de Coordinación/síntesis química , Compuestos Organoplatinos/farmacología , Compuestos Organoplatinos/química , Compuestos Organoplatinos/síntesis química , Especies Reactivas de Oxígeno/metabolismo , Estructura Molecular , Proliferación Celular/efectos de los fármacos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Cisplatino/farmacología , Relación Estructura-Actividad , Relación Dosis-Respuesta a Droga
11.
Regul Toxicol Pharmacol ; 149: 105619, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38614220

RESUMEN

The Xenopus Eleutheroembryonic Thyroid Assay (XETA) was recently published as an OECD Test Guideline for detecting chemicals acting on the thyroid axis. However, the OECD validation did not cover all mechanisms that can potentially be detected by the XETA. This study was therefore initiated to investigate and consolidate the applicability domain of the XETA regarding the following mechanisms: thyroid hormone receptor (THR) agonism, sodium-iodide symporter (NIS) inhibition, thyroperoxidase (TPO) inhibition, deiodinase (DIO) inhibition, glucocorticoid receptor (GR) agonism, and uridine 5'-diphospho-glucuronosyltransferase (UDPGT) induction. In total, 22 chemicals identified as thyroid-active or -inactive in Amphibian Metamorphosis Assays (AMAs) were tested using the XETA OECD Test Guideline. The comparison showed that both assays are highly concordant in identifying chemicals with mechanisms of action related to THR agonism, DIO inhibition, and GR agonism. They also consistently identified the UDPGT inducers as thyroid inactive. NIS inhibition, investigated using sodium perchlorate, was not detected in the XETA. TPO inhibition requires further mechanistic investigations as the reference chemicals tested resulted in opposing response directions in the XETA and AMA. This study contributes refining the applicability domain of the XETA, thereby helping to clarify the conditions where it can be used as an ethical alternative to the AMA.


Asunto(s)
Bioensayo , Disruptores Endocrinos , Metamorfosis Biológica , Simportadores , Glándula Tiroides , Animales , Glándula Tiroides/efectos de los fármacos , Glándula Tiroides/metabolismo , Metamorfosis Biológica/efectos de los fármacos , Bioensayo/métodos , Disruptores Endocrinos/toxicidad , Xenopus laevis , Receptores de Hormona Tiroidea/metabolismo , Receptores de Hormona Tiroidea/agonistas , Yoduro Peroxidasa/metabolismo
12.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-33688042

RESUMEN

Many intracellular signaling pathways are composed of molecular switches, proteins that transition between two states-on and off Typically, signaling is initiated when an external stimulus activates its cognate receptor that, in turn, causes downstream switches to transition from off to on using one of the following mechanisms: activation, in which the transition rate from the off state to the on state increases; derepression, in which the transition rate from the on state to the off state decreases; and concerted, in which activation and derepression operate simultaneously. We use mathematical modeling to compare these signaling mechanisms in terms of their dose-response curves, response times, and abilities to process upstream fluctuations. Our analysis elucidates several operating principles for molecular switches. First, activation increases the sensitivity of the pathway, whereas derepression decreases sensitivity. Second, activation generates response times that decrease with signal strength, whereas derepression causes response times to increase with signal strength. These opposing features allow the concerted mechanism to not only show dose-response alignment, but also to decouple the response time from stimulus strength. However, these potentially beneficial properties come at the expense of increased susceptibility to upstream fluctuations. We demonstrate that these operating principles also hold when the models are extended to include additional features, such as receptor removal, kinetic proofreading, and cascades of switches. In total, we show how the architecture of molecular switches govern their response properties. We also discuss the biological implications of our findings.


Asunto(s)
Modelos Teóricos , Transducción de Señal/fisiología , Cinética
13.
Molecules ; 29(7)2024 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-38611725

RESUMEN

The C(sp2)-aryl sulfonate functional group is found in bioactive molecules, but their synthesis can involve extreme temperatures (>190 °C or flash vacuum pyrolysis) and strongly acidic reaction conditions. Inspired by the 1917 Tyrer industrial process for a sulfa dye that involved an aniline N(sp2)-SO3 intermediate en route to a C(sp2)-SO3 rearranged product, we investigated tributylsulfoammonium betaine (TBSAB) as a milder N-sulfamation to C-sulfonate relay reagent. Initial investigations of a stepwise route involving TBSAB on selected anilines at room temperature enabled the isolation of N(sp2)-sulfamate. Subsequent thermal rearrangement demonstrated the intermediary of a sulfamate en route to the sulfonate; however, it was low-yielding. Investigation of the N-sulfamate to C--sulfonate mechanism through control experiments with variation at the heteroatom positions and kinetic isotope experiments (KIEH/D) confirmed the formation of a key N(sp2)-SO3 intermediate and further confirmed an intermolecular mechanism. Furthermore, compounds without an accessible nitrogen (or oxygen) lone pair did not undergo sulfamation- (or sulfation) -to-sulfonation under these conditions. A one-pot sulfamation and thermal sulfonation reaction was ultimately developed and explored on a range of aniline and heterocyclic scaffolds with high conversions, including N(sp2)-sulfamates (O(sp2)-sulfates) and C(sp2)-sulfonates, in up to 99 and 80% (and 88% for a phenolic example) isolated yield, respectively. Encouragingly, the ability to modulate the ortho-para selectivity of the products obtained was observed under thermal control. A sulfonated analog of the intravenous anesthetic propofol was isolated (88% yield), demonstrating a proof-of-concept modification of a licensed drug alongside a range of nitrogen- and sulfur-containing heterocyclic fragments used in drug discovery.

14.
Molecules ; 29(7)2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38611947

RESUMEN

The Beckmann rearrangement of ketoximes to their corresponding amides, using a Brønsted acid-mediated fragmentation and migration sequence, has found wide-spread industrial application. We postulated that the development of a methodology to access ylideneamino sulfates using tributylsulfoammonium betaine (TBSAB) would afford isolable Beckmann-type intermediates and competent partners for subsequent rearrangement cascades. The ylideneamino sulfates generated, isolated as their tributylammonium salts, are sufficiently activated to undergo Beckmann rearrangement without additional reagent activation. The generation of sulfuric acid in situ from the ylideneamino sulfate giving rise to a routine Beckmann rearrangement and additional amide bond cleavage to the corresponding aniline was detrimental to reaction success. The screening of bases revealed inexpensive sodium bicarbonate to be an effective additive to prevent classic Brønsted acid-mediated fragmentation and achieve optimal conversions of up to 99%.

15.
Molecules ; 29(13)2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38998990

RESUMEN

The tractable preparation of Phase I drug metabolites is a critical step to understand the first-pass behaviour of novel chemical entities (NCEs) in drug discovery. In this study, we have developed a structure-electroactivity relationship (SeAR)-informed electrochemical reaction of the parent 2-chlorophenothiazine and the antipsychotic medication, chlorpromazine. With the ability to dial-in under current controlled conditions, the formation of S-oxide and novel S,S-dioxide metabolites has been achieved for the first time on a multi-milligram scale using a direct batch electrode platform. A potential rationale for the electrochemical formation of these metabolites in situ is proposed using molecular docking to a cytochrome P450 enzyme.


Asunto(s)
Antipsicóticos , Simulación del Acoplamiento Molecular , Fenotiazinas , Antipsicóticos/química , Fenotiazinas/química , Humanos , Técnicas Electroquímicas , Clorpromazina/química , Óxidos/química , Sistema Enzimático del Citocromo P-450/metabolismo , Estructura Molecular
16.
Molecules ; 29(10)2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38792267

RESUMEN

In this article, we introduce a proof-of-concept strategy, Computational Predictive and Electrochemical Detection of Metabolites (CP-EDM), to expedite the discovery of drug metabolites. The use of a bioactive natural product, piperine, that has a well-curated metabolite profile but an unpredictable computational metabolism (Biotransformer v3.0) was selected. We developed an electrochemical reaction to oxidize piperine into a range of metabolites, which were detected by LC-MS. A series of chemically plausible metabolites were predicted based on ion fragmentation patterns. These metabolites were docked into the active site of CYP3A4 using Autodock4.2. From the clustered low-energy profile of piperine in the active site, it can be inferred that the most likely metabolic position of piperine (based on intermolecular distances to the Fe-oxo active site) is the benzo[d][1,3]dioxole motif. The metabolic profile was confirmed by comparison with the literature, and the electrochemical reaction delivered plausible metabolites, vide infra, thus, demonstrating the power of the hyphenated technique of tandem electrochemical detection and computational evaluation of binding poses. Taken together, we outline a novel approach where diverse data sources are combined to predict and confirm a metabolic outcome for a bioactive structure.


Asunto(s)
Alcaloides , Benzodioxoles , Técnicas Electroquímicas , Piperidinas , Alcamidas Poliinsaturadas , Benzodioxoles/química , Benzodioxoles/metabolismo , Alcamidas Poliinsaturadas/metabolismo , Alcamidas Poliinsaturadas/química , Piperidinas/química , Piperidinas/metabolismo , Alcaloides/metabolismo , Alcaloides/química , Técnicas Electroquímicas/métodos , Simulación del Acoplamiento Molecular , Humanos , Cromatografía Liquida/métodos
17.
Plant Physiol ; 188(2): 807-815, 2022 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-34791482

RESUMEN

G-proteins are molecular on-off switches that are involved in transmitting a variety of extracellular signals to their intracellular targets. In animal and yeast systems, the switch property is encoded through nucleotides: a GDP-bound state is the "off-state" and the GTP-bound state is the "on-state". The G-protein cycle consists of the switch turning on through nucleotide exchange facilitated by a G-protein coupled receptor and the switch turning off through hydrolysis of GTP back to GDP, facilitated by a protein designated REGULATOR OF G SIGNALING 1 (RGS). In plants, G-protein signaling dramatically differs from that in animals and yeast. Despite stringent conservation of the nucleotide binding and catalytic structures over the 1.6 billion years that separate the evolution of plants and animals, genetic and biochemical data indicate that nucleotide exchange is less critical for this switch to operate in plants. Also, the loss of the single RGS protein in Arabidopsis (Arabidopsis thaliana) confers unexpectedly weaker phenotypes consistent with a diminished role for the G cycle, at least under static conditions. However, under dynamic conditions, genetic ablation of RGS in Arabidopsis results in a strong phenotype. We explore explanations to this conundrum by formulating a mathematical model that takes into account the accruing evidence for the indispensable role of phosphorylation in G-protein signaling in plants and that the G-protein cycle is needed to process dynamic signal inputs. We speculate that the plant G-protein cycle and its attendant components evolved to process dynamic signals through signaling modulation rather than through on-off, switch-like regulation of signaling. This so-called change detection may impart greater fitness for plants due to their sessility in a dynamic light, temperature, and pest environment.


Asunto(s)
Proteínas de Arabidopsis/fisiología , Arabidopsis/fisiología , Proteínas de Unión al GTP/fisiología , Transducción de Señal/genética , Arabidopsis/genética
18.
Crit Rev Toxicol ; 53(5): 326-338, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37526219

RESUMEN

A systematic review was conducted on the sensitivity of fish testing guidelines to detect the anti-androgenic activity of substances. Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) was used to investigate the conservation of the androgen receptor (AR) between humans and fish, and among fish species recommended in test guidelines. The AR is conserved between fish species and humans (i.e. ligand binding domain [LBD] homology ≥70%) and among the recommended fish species (LBD homology >85%). For model anti-androgens, we evaluated literature data on in vitro anti-androgenic activity in fish-specific receptor-based assays and changes in endpoints indicative of endocrine modulation from in vivo studies. Anti-androgenic activity was most consistently and reliably detected in in vitro and in vivo mechanistic studies with co-exposure to an androgen (spiggin in vitro assay, Rapid Androgen Disruption Activity Reporter [RADAR] Assay, and Androgenised Female Stickleback Screen). Regardless of study design (Fish Short-Term Reproduction Assay [FSTRA], Fish Sexual Development Test [FSDT], partial or full life-cycle tests), or endpoint (vitellogenin, secondary sexual characteristics, gonadal histopathology, sex ratio), there was no consistent evidence for detecting anti-androgenic activity in studies without androgen co-exposure, even for the most potent substances (while less potent substances may induce no (clear) response). Therefore, based on studies without androgen co-exposure (35 FSTRAs and 22 other studies), the other studies (including the FSDT) do not outperform the FSTRA for detecting potent anti-androgenic activity, which if suspected, would be best addressed with a RADAR assay. Overall, fish do not appear particularly sensitive to mammalian anti-androgens.


Asunto(s)
Antagonistas de Andrógenos , Smegmamorpha , Animales , Humanos , Femenino , Andrógenos/farmacología , Peces , Smegmamorpha/fisiología , Mamíferos
19.
Cell ; 133(6): 939-43, 2008 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-18555767

RESUMEN

Studies of the model plant Arabidopsis thaliana may seem to have little impact on advances in medical research, yet a survey of the scientific literature shows that this is a misconception. Many discoveries with direct relevance to human health and disease have been elaborated using Arabidopsis, and several processes important to human biology are more easily studied in this versatile model plant.


Asunto(s)
Arabidopsis/metabolismo , Enfermedad de Alzheimer/metabolismo , Arabidopsis/química , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ritmo Circadiano , Humanos , Inmunidad , Modelos Biológicos , Neoplasias/metabolismo
20.
Molecules ; 28(19)2023 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-37836734

RESUMEN

Amyloid aggregates arise from either the partial or complete loss of the native protein structure or the inability of proteins to attain their native conformation. These aggregates have been linked to several diseases, including Alzheimer's, Parkinson's, and lysozyme amyloidosis. A comprehensive dataset was recently reported, demonstrating the critical role of the protein's surrounding environment in amyloid formation. In this study, we investigated the formation of lysozyme amyloid fibrils induced by sodium dodecyl sulfate (SDS) and the effect of solvents in the medium. Experimental data obtained through fluorescence spectroscopy revealed a notable lag phase in amyloid formation when acetone solution was present. This finding suggested that the presence of acetone in the reaction medium created an unfavorable microenvironment for amyloid fibril formation and impeded the organization of the denatured protein into the fibril form. The in silico data provided insights into the molecular mechanism of the interaction between acetone molecules and the lysozyme protofibril, once acetone presented the best experimental results. It was observed that the lysozyme protofibril became highly unstable in the presence of acetone, leading to the complete loss of its ß-sheet conformation and resulting in an open structure. Furthermore, the solvation layer of the protofibril in acetone solution was significantly reduced compared to that in other solvents, resulting in fewer hydrogen bonds. Consequently, the presence of acetone facilitated the exposure of the hydrophobic portion of the protofibril, precluding the amyloid fibril formation. In summary, our study underscores the pivotal role the surrounding environment plays in influencing amyloid formation.


Asunto(s)
Amiloide , Muramidasa , Dodecil Sulfato de Sodio/química , Amiloide/química , Muramidasa/química , Solventes/química , Acetona
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