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1.
Blood Cells Mol Dis ; 104: 102776, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37391346

RESUMEN

The root cause of sickle cell disease (SCD) has been known for nearly a century, however, few therapies to treat the disease are available. Over several decades of work, with advances in gene editing technology and after several iterations of mice with differing genotype/phenotype relationships, researchers have developed humanized SCD mouse models. However, while a large body of preclinical studies has led to huge gains in basic science knowledge about SCD in mice, this knowledge has not led to the development of effective therapies to treat SCD-related complications in humans, thus leading to frustration with the paucity of translational progress in the SCD field. The use of mouse models to study human diseases is based on the genetic and phenotypic similarities between mouse and humans (face validity). The Berkeley and Townes SCD mice express only human globin chains and no mouse hemoglobin. With this genetic composition, these models present many phenotypic similarities, but also significant discrepancies that should be considered when interpreting preclinical studies results. Reviewing genetic and phenotypic similarities and discrepancies and examining studies that have translated to humans and those that have not, offer a better perspective of construct, face, and predictive validities of humanized SCD mouse models.


Asunto(s)
Anemia de Células Falciformes , Ratones , Humanos , Animales , Anemia de Células Falciformes/genética , Anemia de Células Falciformes/terapia , Anemia de Células Falciformes/complicaciones , Modelos Animales de Enfermedad , Hemoglobinas
2.
Blood Cells Mol Dis ; 104: 102800, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37951090

RESUMEN

Red blood cells (RBC) from patients with sickle cell disease (SCD) have elevated calcium levels at baseline, which are further elevated upon deoxygenation. Here we examined baseline calcium levels and calcium flux in RBCs from a mouse model of SCD mice. We found that akin to humans with SCD, sickle (HbSS) Townes mice, have higher baseline levels and increased calcium flux in RBCs compared to control (HbAA) animals. As HbSS mice, unlike humans with SCD, have high mean corpuscular volume compared with HbAA, we highlight the importance of adjusting biochemical results to number of RBCs rather than hematocrit during the analysis and interpretation of the results. Our findings add to the face validity of humanized sickle cell mice and support its use for studies of RBC calcium flux in SCD.


Asunto(s)
Anemia de Células Falciformes , Índices de Eritrocitos , Humanos , Ratones , Animales , Calcio , Eritrocitos , Eritrocitos Anormales , Hemoglobina Falciforme/genética
3.
Ecol Lett ; 26(7): 1157-1173, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37156097

RESUMEN

The species-energy hypothesis predicts increasing biodiversity with increasing energy in ecosystems. Proxies for energy availability are often grouped into ambient energy (i.e., solar radiation) and substrate energy (i.e., non-structural carbohydrates or nutritional content). The relative importance of substrate energy is thought to decrease with increasing trophic level from primary consumers to predators, with reciprocal effects of ambient energy. Yet, empirical tests are lacking. We compiled data on 332,557 deadwood-inhabiting beetles of 901 species reared from wood of 49 tree species across Europe. Using host-phylogeny-controlled models, we show that the relative importance of substrate energy versus ambient energy decreases with increasing trophic levels: the diversity of zoophagous and mycetophagous beetles was determined by ambient energy, while non-structural carbohydrate content in woody tissues determined that of xylophagous beetles. Our study thus overall supports the species-energy hypothesis and specifies that the relative importance of ambient temperature increases with increasing trophic level with opposite effects for substrate energy.


Asunto(s)
Escarabajos , Ecosistema , Animales , Árboles , Madera , Biodiversidad , Europa (Continente)
4.
Toxicol Appl Pharmacol ; 473: 116606, 2023 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-37336294

RESUMEN

The root cause of sickle cell disease (SCD) is the polymerization of sickle hemoglobin (HbS) leading to sickling of red blood cells (RBC). Earlier studies showed that in patients with SCD, high-dose nitrite inhibited sickling, an effect originally attributed to HbS oxidation to methemoglobin-S even though the anti-sickling effect did not correlate with methemoglobin-S levels. Here, we examined the effects of nitrite on HbS polymerization and on methemoglobin formation in a SCD mouse model. In vitro, at concentrations higher than physiologic (>1 µM), nitrite increased the delay time for polymerization of deoxygenated HbS independently of methemoglobin-S formation, which only occurred at much higher concentrations (>300 µM). In vitro, higher nitrite concentrations oxidized 100% of normal hemoglobin A (HbA), but only 70% of HbS. Dimethyl adipimidate, an anti-polymerization agent, increased the fraction of HbS oxidized by nitrite to 82%, suggesting that polymerized HbS partially contributed to the oxidation-resistant fraction of HbS. At low concentrations (10 µM-1 mM), nitrite did not increase the formation of reactive oxygen species but at high concentrations (10 mM) it decreased sickle RBC viability. In SCD mice, 4-week administration of nitrite yielded no significant changes in methemoglobin or nitrite levels in plasma and RBC, however, it further increased leukocytosis. Overall, these data suggest that nitrite at supra-physiologic concentrations has anti-polymerization properties in vitro and that leukocytosis is a potential nitrite toxicity in vivo. Therefore, to determine whether the anti-polymerization effect of nitrite observed in vitro underlies the decreases in sickling observed in patients with SCD, administration of higher nitrite doses is required.


Asunto(s)
Anemia de Células Falciformes , Hemoglobina Falciforme , Animales , Ratones , Metahemoglobina , Nitritos , Leucocitosis , Anemia de Células Falciformes/tratamiento farmacológico
5.
Ecol Appl ; 33(6): e2890, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37212374

RESUMEN

Outbreaks of the spongy moth Lymantria dispar can have devastating impacts on forest resources and ecosystems. Lepidoptera-specific insecticides, such as Bacillus thuringiensis var. kurstaki (BTK) and tebufenozide, are often deployed to prevent heavy defoliation of the forest canopy. While it has been suggested that using BTK poses less risk to non-target Lepidoptera than leaving an outbreak untreated, in situ testing of this assumption has been impeded by methodological challenges. The trade-offs between insecticide use and outbreaks have yet to be addressed for tebufenozide, which is believed to have stronger side effects than BTK. We investigated the short-term trade-offs between tebufenozide treatments and no-action strategies for the non-target herbivore community in forest canopies. Over 3 years, Lepidoptera and Symphyta larvae were sampled by canopy fogging in 48 oak stands in southeast Germany during and after a spongy moth outbreak. Half of the sites were treated with tebufenozide and changes in canopy cover were monitored. We contrasted the impacts of tebufenozide and defoliator outbreaks on the abundance, diversity, and functional structure of chewing herbivore communities. Tebufenozide treatments strongly reduced Lepidoptera up to 6 weeks after spraying. Populations gradually converged back to control levels after 2 years. Shelter-building species dominated caterpillar assemblages in treated plots in the post-spray weeks, while flight-dimorphic species were slow to recover and remained underrepresented in treated stands 2 years post-treatment. Spongy moth outbreaks had minor effects on leaf chewer communities. Summer Lepidoptera decreased only when severe defoliation occurred, whereas Symphyta declined 1 year after defoliation. Polyphagous species with only partial host plant overlap with the spongy moth were absent from heavily defoliated sites, suggesting greater sensitivity of generalists to defoliation-induced plant responses. These results demonstrate that both tebufenozide treatments and spongy moth outbreaks alter canopy herbivore communities. Tebufenozide had a stronger and longer lasting impact, but it was restricted to Lepidoptera, whereas the outbreak affected both Lepidoptera and Symphyta. These results are tied to the fact that only half of the outbreak sites experienced severe defoliation. This highlights the limited accuracy of current defoliation forecast methods, which are used as the basis for the decision to spray insecticides.


Asunto(s)
Bacillus thuringiensis , Insecticidas , Mariposas Nocturnas , Animales , Ecosistema
6.
Parasitology ; 150(5): 426-433, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36793230

RESUMEN

Anthropogenic interference is a major driver of ecological change in freshwater ecosystems. Pollution and the introduction of new species not only alter macrozoobenthic community structures, but can also affect their respective parasite communities. The ecology of the Weser river system experienced a drastic decline in biodiversity over the past century due to salinization caused by the local potash industry. As a response, the amphipod Gammarus tigrinus was released into the Werra in 1957. A few decades after the introduction and subsequent spread of this North American species, its natural acanthocephalan Paratenuisentis ambiguus was recorded in the Weser in 1988, where it had captured the European eel Anguilla anguilla as a novel host. To assess the recent ecological changes in the acanthocephalan parasite community, we investigated gammarids and eel in the Weser river system. In addition to P. ambiguus, 3 Pomphorhynchus species and Polymorphus cf. minutus were discovered. The introduced G. tigrinus serves as a novel intermediate host for the acanthocephalans Pomphorhynchus tereticollis and P. cf. minutus in the tributary Werra. Pomphorhynchus laevis is persistent in the tributary Fulda in its indigenous host Gammarus pulex. Pomphorhynchus bosniacus colonized the Weser with its Ponto-Caspian intermediate host Dikerogammarus villosus. This study highlights the anthropogenically driven changes in ecology and evolution in the Weser river system. Based on morphological and phylogenetic identification, the shifts in distribution and host usage described here for the first time contribute to the puzzling taxonomy of the genus Pomphorhynchus in times of ecological globalization.


Asunto(s)
Acantocéfalos , Anfípodos , Anguilla , Parásitos , Animales , Ríos , Ecosistema , Filogenia , Interacciones Huésped-Parásitos , Acantocéfalos/fisiología , Anfípodos/parasitología
7.
Blood Cells Mol Dis ; 95: 102660, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35366607

RESUMEN

Polymerization of deoxygenated sickle hemoglobin (HbS) leads to erythrocyte sickling. Enhancing activity of the erythrocyte glycolytic pathway has anti-sickling potential as this reduces 2,3-diphosphoglycerate (2,3-DPG) and increases ATP, factors that decrease HbS polymerization and improve erythrocyte membrane integrity. These factors can be modulated by mitapivat, which activates erythrocyte pyruvate kinase (PKR) and improves sickling kinetics in SCD patients. We investigated mechanisms by which mitapivat may impact SCD by examining its effects in the Townes SCD mouse model. Control (HbAA) and sickle (HbSS) mice were treated with mitapivat or vehicle. Surprisingly, HbSS had higher PKR protein, higher ATP, and lower 2,3-DPG levels, compared to HbAA mice, in contrast with humans with SCD, in whom 2,3-DPG is elevated compared to healthy subjects. Despite our inability to investigate 2,3-DPG-mediated sickling and hemoglobin effects, mitapivat yielded potential benefits in HbSS mice. Mitapivat further increased ATP without significantly changing 2,3-DPG or hemoglobin levels, and decreased levels of leukocytosis, erythrocyte oxidative stress, and the percentage of erythrocytes that retained mitochondria in HbSS mice. These data suggest that, even though Townes HbSS mice have increased PKR activity, further activation of PKR with mitapivat yields potentially beneficial effects that are independent of changes in sickling or hemoglobin levels.


Asunto(s)
Anemia de Células Falciformes , 2,3-Difosfoglicerato/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Modelos Animales de Enfermedad , Eritrocitos/metabolismo , Hemoglobina Falciforme/metabolismo , Hemoglobinas/análisis , Humanos , Ratones , Mitocondrias/metabolismo , Estrés Oxidativo , Piperazinas , Quinolinas
8.
Emerg Infect Dis ; 27(8): 2192-2196, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34087088

RESUMEN

We investigated severe acute respiratory syndrome coronavirus 2 infections in primary schools, kindergartens, and nurseries in Germany. Of 3,169 oropharyngeal swab specimens, only 2 were positive by real-time reverse transcription PCR. Asymptomatic children attending these institutions do not appear to be driving the pandemic when appropriate infection control measures are used.


Asunto(s)
COVID-19 , Casas Cuna , Niño , Alemania/epidemiología , Humanos , Lactante , SARS-CoV-2 , Instituciones Académicas , Vigilancia de Guardia
9.
Biochem Biophys Res Commun ; 555: 196-201, 2021 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-33831782

RESUMEN

The nucleotide-binding domain leucine-rich repeat containing protein 3 (NLRP3) inflammasome is a critical inflammatory mechanism identified in platelets, which controls platelet activation and aggregation. We have recently shown that the platelet NLRP3 inflammasome is upregulated in sickle cell disease (SCD), which is mediated by Bruton tyrosine kinase (BTK). Here, we investigated the effect of pharmacological inhibition of NLRP3 and BTK on platelet aggregation and the formation of in vitro thrombi in Townes SCD mice. Mice were injected for 4 weeks with the NLRP3 inhibitor MCC950, the BTK inhibitor ibrutinib or vehicle control. NLRP3 activity, as monitored by caspase-1 activation, was upregulated in platelets from SCD mice, which was dependent on BTK. Large areas of platelet aggregates detected in the liver of SCD mice were decreased when mice were treated with MCC950 or ibrutinib. Moreover, platelet aggregation and in vitro thrombus formation were upregulated in SCD mice and were inhibited when mice were subjected to pharmacological inhibition of NLRP3 and BTK. Targeting the NLRP3 inflammasome might be a novel approach for antiplatelet therapy in SCD.


Asunto(s)
Agammaglobulinemia Tirosina Quinasa/antagonistas & inhibidores , Anemia de Células Falciformes/fisiopatología , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Agregación Plaquetaria/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Adenina/análogos & derivados , Adenina/farmacología , Agammaglobulinemia Tirosina Quinasa/metabolismo , Animales , Plaquetas/efectos de los fármacos , Plaquetas/patología , Modelos Animales de Enfermedad , Femenino , Furanos , Compuestos Heterocíclicos de 4 o más Anillos/farmacología , Indenos , Inflamasomas , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Ratones Transgénicos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Piperidinas/farmacología , Agregación Plaquetaria/fisiología , Sulfonamidas , Sulfonas/farmacología , Trombosis/tratamiento farmacológico , Trombosis/etiología
10.
Blood Cells Mol Dis ; 86: 102493, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32927249

RESUMEN

Strokes are feared complications of sickle cell disease (SCD) and yield significant neurologic and neurocognitive deficits. However, even without detectable strokes, SCD patients have significant neurocognitive deficits in domains of learning and memory, processing speed and executive function. In these cases, mechanisms unrelated to major cerebrovascular abnormalities likely underlie these deficits. While oxidative stress and stress-related signaling pathways play a role in SCD pathophysiology, their role in cerebral injury remains unknown. We have shown that Townes and BERK SCD mice, while not having strokes, recapitulate neurocognitive deficits reported in humans. We hypothesized that cognitive deficits in SCD mice are associated with cerebral oxidative stress. We showed that SCD mice have increased levels of reactive oxygen species, protein carbonylation, and lipid peroxidation in hippocampus and cortex, thus suggesting increased cerebral oxidative stress. Further, cerebral oxidative stress was associated with caspase-3 activity alterations and vascular endothelial abnormalities, white matter changes, and disruption of the blood brain barrier, similar to those reported after ischemic/oxidative injury. Additionally, after repeated hypoxia/reoxygenation exposure, homozygous Townes had enhanced microglia activation. Our findings indicate that oxidative stress and stress-induced tissue damage is increased in susceptible brain regions, which may, in turn, contribute to neurocognitive deficits in SCD mice.


Asunto(s)
Anemia de Células Falciformes/patología , Células Endoteliales/patología , Estrés Oxidativo , Sustancia Blanca/patología , Anemia de Células Falciformes/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Cognición , Células Endoteliales/metabolismo , Femenino , Humanos , Masculino , Ratones , Sustancia Blanca/metabolismo
11.
Sensors (Basel) ; 21(11)2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34199954

RESUMEN

Knowing the exact nutrient composition of organic fertilizers is a prerequisite for their appropriate application to improve yield and to avoid environmental pollution by over-fertilization. Traditional standard chemical analysis is cost and time-consuming and thus it is unsuitable for a rapid analysis before manure application. As a possible alternative, a handheld X-ray fluorescence (XRF) spectrometer was tested to enable a fast, simultaneous, and on-site analysis of several elements. A set of 62 liquid pig and cattle manures as well as biogas digestates were collected, intensively homogenized and analysed for the macro plant nutrients phosphorus, potassium, magnesium, calcium, and sulphur as well as the micro nutrients manganese, iron, copper, and zinc using the standard lab procedure. The effect of four different sample preparation steps (original, dried, filtered, and dried filter residues) on XRF measurement accuracy was examined. Therefore, XRF results were correlated with values of the reference analysis. The best R2s for each element ranged from 0.64 to 0.92. Comparing the four preparation steps, XRF results for dried samples showed good correlations (0.64 and 0.86) for all elements. XRF measurements using dried filter residues showed also good correlations with R2s between 0.65 and 0.91 except for P, Mg, and Ca. In contrast, correlation analysis for liquid samples (original and filtered) resulted in lower R2s from 0.02 to 0.68, except for K (0.83 and 0.87, respectively). Based on these results, it can be concluded that handheld XRF is a promising measuring system for element analysis in manures and digestates.


Asunto(s)
Biocombustibles , Estiércol , Animales , Bovinos , Fertilizantes/análisis , Nutrientes , Espectrometría por Rayos X , Porcinos
12.
Angew Chem Int Ed Engl ; 59(7): 2730-2734, 2020 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-31596046

RESUMEN

Owing to its outstanding elastic properties, the nitride spinel γ-Si3 N4 is of considered interest for materials scientists and chemists. DFT calculations suggest that Si3 N4 -analog beryllium phosphorus nitride BeP2 N4 adopts the spinel structure at elevated pressures as well and shows outstanding elastic properties. Herein, we investigate phenakite-type BeP2 N4 by single-crystal synchrotron X-ray diffraction and report the phase transition into the spinel-type phase at 47 GPa and 1800 K in a laser-heated diamond anvil cell. The structure of spinel-type BeP2 N4 was refined from pressure-dependent in situ synchrotron powder X-ray diffraction measurements down to ambient pressure, which proves spinel-type BeP2 N4 a quenchable and metastable phase at ambient conditions. Its isothermal bulk modulus was determined to 325(8) GPa from equation of state, which indicates that spinel-type BeP2 N4 is an ultraincompressible material.

13.
Biochem Biophys Res Commun ; 508(2): 614-619, 2019 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-30522866

RESUMEN

Platelets play a critical role in the pathophysiology of peripheral arterial disease (PAD). The mechanisms by which muscle ischemia regulates aggregation of platelets are poorly understood. We have recently identified the Nod-like receptor nucleotide-binding domain leucine rich repeat containing protein 3 (NLRP3) expressed by platelets as a critical regulator of platelet activation and aggregation, which may be triggered by activation of toll-like receptor 4 (TLR4). In this study, we performed femoral artery ligation (FAL) in transgenic mice with platelet-specific ablation of TLR4 (TLR4 PF4) and in NLRP3 knockout (NLRP3-/-) mice. NLRP3 inflammasome activity of circulating platelets, as monitored by activation of caspase-1 and cleavage of interleukin-1ß (IL-1ß), was upregulated in mice subjected to FAL. Genetic ablation of TLR4 in platelets led to decreased platelet caspase 1 activation and platelet aggregation, which was reversed by the NLRP3 activator Nigericin. Two weeks after the induction of FAL, ischemic limb perfusion was increased in TLR4 PF4 and NLRP3-/- mice as compared to control mice. Hence, activation of platelet TLR4/NLRP3 signaling plays a critical role in upregulating platelet aggregation and interfering with perfusion recovery in muscle ischemia and may represent a therapeutic target to improve limb salvage.


Asunto(s)
Modelos Animales de Enfermedad , Miembro Posterior/metabolismo , Inflamasomas/metabolismo , Isquemia/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Receptor Toll-Like 4/metabolismo , Animales , Inflamasomas/sangre , Isquemia/sangre , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteína con Dominio Pirina 3 de la Familia NLR/sangre , Proteína con Dominio Pirina 3 de la Familia NLR/deficiencia , Activación Plaquetaria , Agregación Plaquetaria , Transducción de Señal , Receptor Toll-Like 4/sangre , Regulación hacia Arriba
14.
Ann Hematol ; 98(7): 1603-1610, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31020347

RESUMEN

Platelets are activated in solid cancers, including pancreatic ductal adenocarcinoma (PDA), a highly aggressive malignancy with a devastating prognosis and limited therapeutic options. The mechanisms by which activated platelets regulate tumor progression are poorly understood. The nucleotide-binding domain leucine-rich repeat containing protein 3 (NLRP3) inflammasome is a key inflammatory mechanism recently identified in platelets, which controls platelet activation and aggregation. In an orthotopic PDA mouse model involving surgical implantation of Panc02 murine cancer cells into the tail of the pancreas, we show that the NLRP3 inflammasome in circulating platelets is upregulated in pancreatic cancer. Pharmacological inhibition or genetic ablation of NLRP3 in platelets resulted in decreased platelet activation, platelet aggregation, and tumor progression. Moreover, interfering with platelet NLRP3 signaling significantly improved survival of tumor-bearing mice. Hence, the platelet NLRP3 inflammasome plays a critical role in PDA and might represent a novel therapeutic target.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias Experimentales/metabolismo , Neoplasias Pancreáticas/metabolismo , Agregación Plaquetaria , Regulación hacia Arriba , Animales , Plaquetas , Línea Celular Tumoral , Inflamasomas/genética , Ratones , Ratones Noqueados , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteínas de Neoplasias/genética , Neoplasias Experimentales/genética , Neoplasias Experimentales/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología
15.
Sensors (Basel) ; 19(20)2019 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-31652584

RESUMEN

On a grassland field with sandy soils in Northeast Germany (Brandenburg), vegetation indices from multi-spectral UAV-based remote sensing were used to predict grassland biomass productivity. These data were combined with soil pH value and apparent electrical conductivity (ECa) from on-the-go proximal sensing serving as indicators for soil-borne causes of grassland biomass variation. The field internal magnitude of spatial variability and hidden correlations between the variables of investigation were analyzed by means of geostatistics and boundary-line analysis to elucidate the influence of soil pH and ECa on the spatial distribution of biomass. Biomass and pH showed high spatial variability, which necessitates high resolution data acquisition of soil and plant properties. Moreover, boundary-line analysis showed grassland biomass maxima at pH values between 5.3 and 7.2 and ECa values between 3.5 and 17.5 mS m-1. After calibrating ECa to soil moisture, the ECa optimum was translated to a range of optimum soil moisture from 7% to 13%. This matches well with to the plant-available water content of the predominantly sandy soil as derived from its water retention curve. These results can be used in site-specific management decisions to improve grassland biomass productivity in low-yield regions of the field due to soil acidity or texture-related water scarcity.


Asunto(s)
Biomasa , Pradera , Tecnología de Sensores Remotos , Suelo/química , Conductividad Eléctrica , Concentración de Iones de Hidrógeno , Modelos Lineales
16.
Angew Chem Int Ed Engl ; 58(11): 3398-3401, 2019 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-30653792

RESUMEN

Non-metal nitrides such as BN, Si3 N4 , and P3 N5 meet numerous demands on high-performance materials, and their high-pressure polymorphs exhibit outstanding mechanical properties. Herein, we present the silicon phosphorus nitride imide SiP2 N4 NH featuring sixfold coordinated Si. Using the multi-anvil technique, SiP2 N4 NH was obtained by high-pressure high-temperature synthesis at 8 GPa and 1100 °C with in situ formed HCl acting as a mineralizer. Its structure was elucidated by a combination of single-crystal X-ray diffraction and solid-state NMR measurements. Moreover, SiP2 N4 NH was characterized by energy-dispersive X-ray spectroscopy and (temperature-dependent) powder X-ray diffraction. The highly condensed Si/P/N framework features PN4 tetrahedra as well as the rare motif of SiN6 octahedra, and is discussed in the context of ambient-pressure motifs competing with close-packing of nitride anions, representing a missing link in the high-pressure chemistry of non-metal nitrides.

17.
Angew Chem Int Ed Engl ; 58(27): 9060-9063, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-31020764

RESUMEN

The high-pressure behavior of non-metal nitrides is of special interest for inorganic and theoretical chemistry as well as materials science, as these compounds feature intriguing elastic properties. The double nitride α-BP3 N6 was investigated by in situ single-crystal X-ray diffraction (XRD) upon cold compression to a maximum pressure of about 42 GPa, and its isothermal bulk modulus at ambient conditions was determined to be 146(6) GPa. At maximum pressure the sample was laser-heated, which resulted in the formation of an unprecedented high-pressure polymorph, ß-BP3 N6 . Its structure was elucidated by single-crystal XRD, and can be described as a decoration of a distorted hexagonal close packing of N with B in tetrahedral and P in octahedral voids. Hence, ß-BP3 N6 is the first nitride to contain PN6 octahedra, representing the much sought-after proof of principle for sixfold N-coordinated P that has been predicted for numerous high-pressure phases of nitrides.

18.
Br J Haematol ; 180(5): 761-767, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29383704

RESUMEN

Platelets play a critical role at the interphase of thrombosis and inflammation, key features in haemolysis-associated disorders. Exercising this role requires expression of pattern recognition receptors by platelets, including toll-like receptor 4 (TLR4) and nucleotide-binding domain leucine rich repeat containing protein 3 (NLRP3), the latter forming intraplatelet multiprotein inflammasome complexes. Platelets are a potential target of various damage-associated molecular pattern (DAMP) molecules, such as free haem, a degradation by-product of haemoglobin oxidation during haemolysis, and high-mobility group box 1 (HMGB1), a DNA-binding protein released by dying or stressed cells and activated platelets. We have recently identified platelet TLR4, NLRP3, and Bruton tyrosine kinase (BTK) as critical regulators of platelet aggregation and thrombus formation, suggesting that the BTK inhibitor ibrutinib is a potential therapeutic target. Increasing evidence suggests that these and other DAMP-driven signalling mechanisms employed by platelets might be key in mediating inflammation and thrombosis encountered in haemolytic disorders. However, the precise regulatory triggers and their clinical relevance are poorly understood. We provide new insights into these less-well characterised platelet mechanisms, which are potentially targetable in haemolytic disorders.


Asunto(s)
Plaquetas/fisiología , Enfermedades Hematológicas/etiología , Hemólisis/fisiología , Inflamación/etiología , Trombosis/etiología , Anemia de Células Falciformes/etiología , Proteína HMGB1/metabolismo , Humanos , Proteína con Dominio Pirina 3 de la Familia NLR , Transducción de Señal
19.
Chemistry ; 24(53): 14275-14281, 2018 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-30004596

RESUMEN

Nitridophosphates and imidonitridophosphates show intriguing structural diversity, including unprecedented structure types. Highly condensed strontium imidonitridophosphate SrP3 N5 NH has been synthesized at 8 GPa and 1100 °C using a high-pressure high-temperature approach starting from stoichiometric amounts of Sr(N3 )2 , P3 N5 and NH4 Cl. Herein, NH4 Cl was used as a hydrogen source and as a precursor for in situ formation of SrCl2 , which acts as mineralizer and facilitates growth of single-crystals with a diameter of ≤30 µm. SrP3 N5 NH (P21 /c (no. 14), a=5.01774(2), b=8.16912(4), c=12.70193(5) Å, ß=101.7848(3)°, Z=4) adopts an unprecedented network structure, represented by the point symbol (3.4.5.6.72 )(3.4.5.72 .8)(3.6.73 .8). This unique three nodal P/N(H) network is stabilized by moderately strong hydrogen bonds causing a structure-directing effect, which has not yet been reported for imidonitridophosphates.

20.
J Allergy Clin Immunol ; 140(4): 1054-1067.e10, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28216434

RESUMEN

BACKGROUND: The Nod-like receptor NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) and Bruton tyrosine kinase (BTK) are protagonists in innate and adaptive immunity, respectively. NLRP3 senses exogenous and endogenous insults, leading to inflammasome activation, which occurs spontaneously in patients with Muckle-Wells syndrome; BTK mutations cause the genetic immunodeficiency X-linked agammaglobulinemia (XLA). However, to date, few proteins that regulate NLRP3 inflammasome activity in human primary immune cells have been identified, and clinically promising pharmacologic targeting strategies remain elusive. OBJECTIVE: We sought to identify novel regulators of the NLRP3 inflammasome in human cells with a view to exploring interference with inflammasome activity at the level of such regulators. METHODS: After proteome-wide phosphoproteomics, the identified novel regulator BTK was studied in human and murine cells by using pharmacologic and genetic BTK ablation. RESULTS: Here we show that BTK is a critical regulator of NLRP3 inflammasome activation: pharmacologic (using the US Food and Drug Administration-approved inhibitor ibrutinib) and genetic (in patients with XLA and Btk knockout mice) BTK ablation in primary immune cells led to reduced IL-1ß processing and secretion in response to nigericin and the Staphylococcus aureus toxin leukocidin AB (LukAB). BTK affected apoptosis-associated speck-like protein containing a CARD (ASC) speck formation and caspase-1 cleavage and interacted with NLRP3 and ASC. S aureus infection control in vivo and IL-1ß release from cells of patients with Muckle-Wells syndrome were impaired by ibrutinib. Notably, IL-1ß processing and release from immune cells isolated from patients with cancer receiving ibrutinib therapy were reduced. CONCLUSION: Our data suggest that XLA might result in part from genetic inflammasome deficiency and that NLRP3 inflammasome-linked inflammation could potentially be targeted pharmacologically through BTK.


Asunto(s)
Agammaglobulinemia/genética , Síndromes Periódicos Asociados a Criopirina/genética , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Infecciones Estafilocócicas/inmunología , Staphylococcus aureus/inmunología , Inmunidad Adaptativa , Proteínas Adaptadoras Transductoras de Señales , Agammaglobulinemia Tirosina Quinasa , Animales , Proteínas Reguladoras de la Apoptosis , Proteínas Bacterianas/inmunología , Células Cultivadas , Humanos , Inmunidad Innata , Leucocidinas/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Terapia Molecular Dirigida , Proteínas NLR , Nigericina/inmunología , Proteínas Tirosina Quinasas/genética , Proteómica , Dominio Pirina/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptor de Lamina B
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