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1.
Cell ; 184(2): 521-533.e14, 2021 01 21.
Artículo en Inglés | MEDLINE | ID: mdl-33373587

RESUMEN

Development of γ-secretase inhibitors (GSIs) and modulators (GSMs) represents an attractive therapeutic opportunity for Alzheimer's disease (AD) and cancers. However, how these GSIs and GSMs target γ-secretase has remained largely unknown. Here, we report the cryoelectron microscopy (cryo-EM) structures of human γ-secretase bound individually to two GSI clinical candidates, Semagacestat and Avagacestat, a transition state analog GSI L685,458, and a classic GSM E2012, at overall resolutions of 2.6-3.1 Å. Remarkably, each of the GSIs occupies the same general location on presenilin 1 (PS1) that accommodates the ß strand from amyloid precursor protein or Notch, interfering with substrate recruitment. L685,458 directly coordinates the two catalytic aspartate residues of PS1. E2012 binds to an allosteric site of γ-secretase on the extracellular side, potentially explaining its modulating activity. Structural analysis reveals a set of shared themes and variations for inhibitor and modulator recognition that will guide development of the next-generation substrate-selective inhibitors.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Preparaciones Farmacéuticas/química , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Alanina/análogos & derivados , Alanina/farmacología , Secuencia de Aminoácidos , Secretasas de la Proteína Precursora del Amiloide/ultraestructura , Azepinas/farmacología , Sitios de Unión , Microscopía por Crioelectrón , Células HEK293 , Humanos , Modelos Biológicos , Modelos Moleculares , Oxadiazoles/química , Oxadiazoles/farmacología , Presenilina-1/química , Presenilina-1/metabolismo , Unión Proteica/efectos de los fármacos , Conformación Proteica , Relación Estructura-Actividad , Especificidad por Sustrato/efectos de los fármacos , Sulfonamidas/química , Sulfonamidas/farmacología
2.
Nature ; 612(7940): 519-527, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36477534

RESUMEN

In mice and humans, sleep quantity is governed by genetic factors and exhibits age-dependent variation1-3. However, the core molecular pathways and effector mechanisms that regulate sleep duration in mammals remain unclear. Here, we characterize a major signalling pathway for the transcriptional regulation of sleep in mice using adeno-associated virus-mediated somatic genetics analysis4. Chimeric knockout of LKB1 kinase-an activator of AMPK-related protein kinase SIK35-7-in adult mouse brain markedly reduces the amount and delta power-a measure of sleep depth-of non-rapid eye movement sleep (NREMS). Downstream of the LKB1-SIK3 pathway, gain or loss-of-function of the histone deacetylases HDAC4 and HDAC5 in adult brain neurons causes bidirectional changes of NREMS amount and delta power. Moreover, phosphorylation of HDAC4 and HDAC5 is associated with increased sleep need, and HDAC4 specifically regulates NREMS amount in posterior hypothalamus. Genetic and transcriptomic studies reveal that HDAC4 cooperates with CREB in both transcriptional and sleep regulation. These findings introduce the concept of signalling pathways targeting transcription modulators to regulate daily sleep amount and demonstrate the power of somatic genetics in mouse sleep research.


Asunto(s)
Transducción de Señal , Duración del Sueño , Transcripción Genética , Animales , Ratones , Regulación de la Expresión Génica , Fosforilación , Transducción de Señal/fisiología , Sueño de Onda Lenta/genética , Perfilación de la Expresión Génica
3.
Nature ; 565(7738): 192-197, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30598546

RESUMEN

Aberrant cleavage of Notch by γ-secretase leads to several types of cancer, but how γ-secretase recognizes its substrate remains unknown. Here we report the cryo-electron microscopy structure of human γ-secretase in complex with a Notch fragment at a resolution of 2.7 Å. The transmembrane helix of Notch is surrounded by three transmembrane domains of PS1, and the carboxyl-terminal ß-strand of the Notch fragment forms a ß-sheet with two substrate-induced ß-strands of PS1 on the intracellular side. Formation of the hybrid ß-sheet is essential for substrate cleavage, which occurs at the carboxyl-terminal end of the Notch transmembrane helix. PS1 undergoes pronounced conformational rearrangement upon substrate binding. These features reveal the structural basis of Notch recognition and have implications for the recruitment of the amyloid precursor protein by γ-secretase.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Secretasas de la Proteína Precursora del Amiloide/ultraestructura , Microscopía por Crioelectrón , Receptores Notch/metabolismo , Receptores Notch/ultraestructura , Secuencia de Aminoácidos , Secretasas de la Proteína Precursora del Amiloide/química , Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Humanos , Ratones , Modelos Moleculares , Unión Proteica , Receptores Notch/química , Especificidad por Sustrato
4.
Mol Ther ; 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38715363

RESUMEN

Human papillomavirus (HPV) 16 and 18 infections are related to many human cancers. Despite several preventive vaccines for high-risk (hr) HPVs, there is still an urgent need to develop therapeutic HPV vaccines for targeting pre-existing hrHPV infections and lesions. In this study, we developed a lipid nanoparticle (LNP)-formulated mRNA-based HPV therapeutic vaccine (mHTV)-03E2, simultaneously targeting the E2/E6/E7 of both HPV16 and HPV18. mHTV-03E2 dramatically induced antigen-specific cellular immune responses, leading to significant CD8+ T cell infiltration and cytotoxicity in TC-1 tumors derived from primary lung epithelial cells of C57BL/6 mice expressing HPV E6/E7 antigens, mediated significant tumor regression, and prolonged animal survival, in a dose-dependent manner. We further demonstrated significant T cell immunity against HPV16/18 E6/E7 antigens for up to 4 months post-vaccination in immunological and distant tumor rechallenging experiments, suggesting robust memory T cell immunity against relapse. Finally, mHTV-03E2 synergized with immune checkpoint blockade to inhibit tumor growth and extend animal survival, indicating the potential in combination therapy. We conclude that mHTV-03E2 is an excellent candidate therapeutic mRNA vaccine for treating malignancies caused by HPV16 or HPV18 infections.

5.
PLoS Genet ; 18(10): e1010433, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36301831

RESUMEN

Circular RNAs (circRNAs) are a new group of noncoding/regulatory RNAs that are particularly abundant in the nervous system, however, their physiological functions are underexplored. Here we report that the brain-enriched circular RNA Edis (Ect4-derived immune suppressor) plays an essential role in neuronal development in Drosophila. We show that depletion of Edis in vivo causes defects in axonal projection patterns of mushroom body (MB) neurons in the brain, as well as impaired locomotor activity and shortened lifespan of adult flies. In addition, we find that the castor gene, which encodes a transcription factor involved in neurodevelopment, is upregulated in Edis knockdown neurons. Notably, castor overexpression phenocopies Edis knockdown, and reducing castor levels suppresses the neurodevelopmental phenotypes in Edis-depleted neurons. Furthermore, chromatin immunoprecipitation analysis reveals that the transcription factor Relish, which plays a key role in regulating innate immunity signaling, occupies a pair of sites at the castor promoter, and that both sites are required for optimal castor gene activation by either immune challenge or Edis depletion. Lastly, Relish mutation and/or depletion can rescue both the castor gene hyperactivation phenotype and neuronal defects in Edis knockdown animals. We conclude that the circular RNA Edis acts through Relish and castor to regulate neuronal development.


Asunto(s)
Proteínas de Drosophila , Drosophila , Animales , Drosophila/genética , ARN Circular/genética , Proteínas de Drosophila/genética , Factores de Transcripción/genética , Cuerpos Pedunculados , Drosophila melanogaster/fisiología
6.
Proc Natl Acad Sci U S A ; 119(12): e2122292119, 2022 03 22.
Artículo en Inglés | MEDLINE | ID: mdl-35298330

RESUMEN

Aberrant cleavage of amyloid precursor protein (APP) by γ-secretase is closely associated with Alzheimer's disease (AD). γ-secretase activating protein (GSAP) specifically promotes γ-secretase­mediated cleavage of APP. However, the underlying mechanism remains enigmatic. Here, we demonstrate that the 16-kDa C-terminal fragment of GSAP (GSAP-16K) undergoes phase separation in vitro and forms puncta-like condensates in cells. GSAP-16K exerts dual modulation on γ-secretase cleavage; GSAP-16K in dilute phase increases APP­C-terminal 99-residue fragment (C99) cleavage toward preferred production of ß-amyloid peptide 42 (Aß42), but GSAP-16K condensates reduce APP-C99 cleavage through substrate sequestration. Notably, the Aß42/Aß40 ratio is markedly elevated with increasing concentrations of GSAP-16K. GSAP-16K stably associates with APP-C99 through specific sequence elements. These findings mechanistically explain GSAP-mediated modulation of γ-secretase activity that may have ramifications on the development of potential therapeutics.


Asunto(s)
Enfermedad de Alzheimer , Secretasas de la Proteína Precursora del Amiloide , Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Humanos , Fragmentos de Péptidos/metabolismo
7.
PLoS Genet ; 18(10): e1010429, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36301822

RESUMEN

Circular RNAs (circRNAs) are widely expressed in eukaryotes. However, only a subset has been functionally characterized. We identify and validate a collection of circRNAs in Drosophila, and show that depletion of the brain-enriched circRNA Edis (circ_Ect4) causes hyperactivation of antibacterial innate immunity both in cultured cells and in vivo. Notably, Edis depleted flies display heightened resistance to bacterial infection and enhanced pathogen clearance. Conversely, ectopic Edis expression blocks innate immunity signaling. In addition, inactivation of Edis in vivo leads to impaired locomotor activity and shortened lifespan. Remarkably, these phenotypes can be recapitulated with neuron-specific depletion of Edis, accompanied by defective neurodevelopment. Furthermore, inactivation of Relish suppresses the innate immunity hyperactivation phenotype in the fly brain. Moreover, we provide evidence that Edis encodes a functional protein that associates with and compromises the processing and activation of the immune transcription factor Relish. Importantly, restoring Edis expression or ectopic expression of Edis-encoded protein suppresses both innate immunity and neurodevelopment phenotypes elicited by Edis depletion. Thus, our study establishes Edis as a key regulator of neurodevelopment and innate immunity.


Asunto(s)
Inmunidad Innata , ARN Circular , Animales , ARN Circular/genética , Inmunidad Innata/genética , Factores de Transcripción/genética , Drosophila/genética , Drosophila/metabolismo , Transducción de Señal , ARN/genética
8.
J Am Chem Soc ; 146(6): 3890-3899, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38294957

RESUMEN

Topological insulators offer significant potential to revolutionize diverse fields driven by nontrivial manifestations of their topological electronic band structures. However, the realization of superior integration between exotic topological states and superconductivity for practical applications remains a challenge, necessitating a profound understanding of intricate mechanisms. Here, we report experimental observations for a novel superconducting phase in the pressurized second-order topological insulator candidate Ta2Pd3Te5, and the high-pressure phase maintains its original ambient pressure lattice symmetry up to 45 GPa. Our in situ high-pressure synchrotron X-ray diffraction, electrical transport, infrared reflectance, and Raman spectroscopy measurements, in combination with rigorous theoretical calculations, provide compelling evidence for the association between the superconducting behavior and the densified phase. The electronic state change around 20 GPa was found to modify the topology of the Fermi surface directly, which synergistically fosters the emergence of robust superconductivity. In-depth comprehension of the fascinating properties exhibited by the compressed Ta2Pd3Te5 phase is achieved, highlighting the extraordinary potential of topological insulators for exploring and investigating high-performance electronic advanced devices under extreme conditions.

9.
Biochem Biophys Res Commun ; 696: 149501, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38232667

RESUMEN

Irisin is protective in the cardiac microenvironment and can resist doxorubicin-induced cardiotoxicity. The purpose of this study was to investigate the connection between Irisin, endothelial cell integrity, and mitochondrial dynamics. Primary cardiac microvascular endothelial cells (CMECs) were used to explore the regulatory effects of Irisin on tight junction proteins, mitochondrial dynamics, ß-catenin expression, and transcriptional activity. Results showed that Irisin can suppress doxorubicin-induced upregulation of MMP2 and MMP9, thereby reducing the degradation of tight junction proteins (ZO-1 and Claudin-5) and VE-cadherin. The preservation of Claudin-5 contributes to maintaining Mfn2 expression, which in turn supports mitochondrial fusion. Although Irisin restores doxorubicin-induced downregulation of ß-catenin, it concurrently limits ß-catenin transcriptional activity via Mfn2-mediated sulfenylation. Therefore, this study revealed a novel mechanism linking the protective effects of Irisin on the tight junction proteins and mitochondrial dynamics upon doxorubicin exposure.


Asunto(s)
Fibronectinas , beta Catenina , beta Catenina/metabolismo , Fibronectinas/metabolismo , Claudina-5/metabolismo , Dinámicas Mitocondriales , Células Endoteliales/metabolismo , Proteínas de Uniones Estrechas/metabolismo , Doxorrubicina/farmacología , Doxorrubicina/metabolismo , Uniones Estrechas/metabolismo
10.
J Intern Med ; 295(5): 679-694, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38528394

RESUMEN

BACKGROUND: The association of a broad spectrum of infectious diseases with cardiovascular outcomes remains unclear. OBJECTIVES: We aim to provide the cardiovascular risk profiles associated with a wide range of infectious diseases and explore the extent to which infections reduce life expectancy. METHODS: We ascertained exposure to 900+ infectious diseases before cardiovascular disease (CVD) onset in 453,102 participants from the UK Biobank study. Time-varying Cox proportional hazard models were used. Life table was used to estimate the life expectancy of individuals aged ≥50 with different levels of infection burden (defined as the number of infection episodes over time and the number of co-occurring infections). RESULTS: Infectious diseases were associated with a greater risk of CVD events (adjusted HR [aHR] 1.79 [95% confidence interval {CI} 1.74-1.83]). For type-specific analysis, bacterial infection with sepsis had the strongest risk of CVD events [aHR 4.76 (4.35-5.20)]. For site-specific analysis, heart and circulation infections posed the greatest risk of CVD events [aHR 4.95 (95% CI 3.77-6.50)], whereas noncardiac infections also showed excess risk [1.77 (1.72-1.81)]. Synergistic interactions were observed between infections and genetic risk score. A dose-response relationship was found between infection burden and CVD risks (p-trend <0.001). Infection burden >1 led to a CVD-related life loss at age 50 by 9.3 years [95% CI 8.6-10.3]) for men and 6.6 years [5.5-7.8] for women. CONCLUSIONS: The magnitude of the infection-CVD association showed specificity in sex, pathogen type, infection burden, and infection site. High genetic risk and infection synergistically increased the CVD risk.


Asunto(s)
Enfermedades Cardiovasculares , Infección Hospitalaria , Masculino , Humanos , Femenino , Persona de Mediana Edad , Enfermedades Cardiovasculares/epidemiología , Factores de Riesgo , Esperanza de Vida , Hospitales
11.
Small ; 20(3): e2305943, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37681501

RESUMEN

Photoresponsive nitric oxide (NO)-releasing materials (NORMs) enable the spatiotemporal delivery of NO to facilitate their potential applications in physiological conditions. Here two novel metal-organic frameworks (MOFs)-based photoactive NORMs achieved by the incorporation of prefunctionalized NO donors into the photosensitive Fe-MOFs via a postmodification strategy is reported. The modified Fe-MOFs display superior photoactivity of NO release when exposed to visible light (up to 720 nm). Significantly, the visible-light-driven NO release properties are further corroborated by their efficient antibacterial performance.


Asunto(s)
Estructuras Metalorgánicas , Óxido Nítrico , Electrones , Luz , Antibacterianos/farmacología
12.
Small ; : e2402037, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38511536

RESUMEN

Enhancing the low-potential capacity of anode materials is significant in boosting the operating voltage of full-cells and constructing high energy-density energy storage devices. Graphitic carbons exhibit outstanding low-potential potassium storage performance, but show a low K+ diffusion kinetics. Herein, in situ defect engineering in graphitic nanocarbon is achieved by an atomic self-activation strategy to boost the accessible low-voltage insertion. Graphitic carbon layers grow on nanoscale-nickel to form the graphitic nanosphere with short-range ordered microcrystalline due to nickel graphitization catalyst. Meanwhile, the widely distributed K+ in the precursor induces the activation of surrounding carbon atoms to in situ generate carbon vacancies as channels. The graphite microcrystals with defect channels realize reversible K+ intercalation at low-potential and accessible ion diffusion kinetics, contributing to high reversible capacity (209 mAh g-1 at 0.05 A g-1 under 0.8 V) and rate capacity (103.2 mAh g-1 at 1 A g-1). The full-cell with Prussian blue cathode and graphitic nanocarbon anode maintains an obvious working platform at ca. 3.0 V. This work provides a strategy for the in situ design of carbon anode materials and gives insights into the potassium storage mechanism at low-potential for high-performance full-cells.

13.
New Phytol ; 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38849320

RESUMEN

Flowering is a vital agronomic trait that determines the economic value of most ornamental plants. The flowering time of rose (Rosa spp.) is photoperiod insensitive and is thought to be tightly controlled by light intensity, although the detailed molecular mechanism remains unclear. Here, we showed that rose plants flower later under low-light (LL) intensity than under high-light (HL) intensity, which is mainly related to the stability of PHYTOCHROME-INTERACTING FACTORs (RcPIFs) mediated by OPEN STOMATA 1-Like (RcOST1L) under different light intensity regimes. We determined that HL conditions trigger the rapid phosphorylation of RcPIFs before their degradation. A yeast two-hybrid screen identified the kinase RcOST1L as interacting with RcPIF4. Moreover, RcOST1L positively regulated rose flowering and directly phosphorylated RcPIF4 on serine 198 to promote its degradation under HL conditions. Additionally, phytochrome B (RcphyB) enhanced RcOST1L-mediated phosphorylation of RcPIF4 via interacting with the active phyB-binding motif. RcphyB was activated upon HL and recruited RcOST1L to facilitate its nuclear accumulation, in turn leading to decreased stability of RcPIF4 and flowering acceleration. Our findings illustrate how RcPIF abundance safeguards proper rose flowering under different light intensities, thus uncovering the essential role of RcOST1L in the RcphyB-RcPIF4 module in flowering.

14.
Cardiovasc Diabetol ; 23(1): 201, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38867282

RESUMEN

BACKGROUND: It's unclear if excess visceral adipose tissue (VAT) mass in individuals with prediabetes can be countered by adherence to a Mediterranean lifestyle (MEDLIFE). We aimed to examine VAT mass, MEDLIFE adherence, and their impact on type 2 diabetes (T2D) and diabetic microvascular complications (DMC) in individuals with prediabetes. METHODS: 11,267 individuals with prediabetes from the UK Biobank cohort were included. VAT mass was predicted using a non-linear model, and adherence to the MEDLIFE was evaluated using the 25-item MEDLIFE index, encompassing categories such as "Mediterranean food consumption," "Mediterranean dietary habits," and "Physical activity, rest, social habits, and conviviality." Both VAT and MEDLIFE were categorized into quartiles, resulting in 16 combinations. Incident cases of T2D and related DMC were identified through clinical records. Cox proportional-hazards regression models were employed to examine associations, adjusting for potential confounding factors. RESULTS: Over a median follow-up of 13.77 years, we observed 1408 incident cases of T2D and 714 cases of any DMC. High adherence to the MEDLIFE, compared to the lowest quartile, reduced a 16% risk of incident T2D (HR: 0.84, 95% CI: 0.71-0.98) and 31% for incident DMC (0.69, 0.56-0.86). Conversely, compared to the lowest quartile of VAT, the highest quartile increased the risk of T2D (5.95, 4.72-7.49) and incident any DMC (1.79, 1.36-2.35). We observed an inverse dose-response relationship between MEDLIFE and T2D/DMC, and a dose-response relationship between VAT and all outcomes (P for trend < 0.05). Restricted cubic spline analysis confirmed a nearly linear dose-response pattern across all associations. Compared to individuals with the lowest MEDLIFE quartile and highest VAT quartile, those with the lowest T2D risk had the lowest VAT and highest MEDLIFE (0.12, 0.08-0.19). High MEDLIFE was linked to reduced T2D risk across all VAT categories, except in those with the highest VAT quartile. Similar trends were seen for DMC. CONCLUSION: High adherence to MEDLIFE reduced T2D and MDC risk in individuals with prediabetes, while high VAT mass increases it, but MEDLIFE adherence may offset VAT's risk partly. The Mediterranean lifestyle's adaptability to diverse populations suggests promise for preventing T2D.


Asunto(s)
Diabetes Mellitus Tipo 2 , Angiopatías Diabéticas , Dieta Mediterránea , Grasa Intraabdominal , Estado Prediabético , Factores Protectores , Conducta de Reducción del Riesgo , Humanos , Estado Prediabético/epidemiología , Estado Prediabético/diagnóstico , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiología , Masculino , Femenino , Persona de Mediana Edad , Grasa Intraabdominal/fisiopatología , Anciano , Factores de Riesgo , Medición de Riesgo , Angiopatías Diabéticas/epidemiología , Angiopatías Diabéticas/diagnóstico , Angiopatías Diabéticas/prevención & control , Factores de Tiempo , Incidencia , Adiposidad , Reino Unido/epidemiología , Adulto , Dieta Saludable , Ejercicio Físico , Estilo de Vida Saludable , Obesidad Abdominal/diagnóstico , Obesidad Abdominal/epidemiología , Obesidad Abdominal/fisiopatología , Estudios Prospectivos
15.
Opt Lett ; 49(12): 3476-3479, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38875649

RESUMEN

A high average power re-frequency operation Fe:ZnSe laser using laser diode side-pumped free-running Er:YAG lasers as activating sources is presented. Two pieces of subsurface layer doped Fe:ZnSe polycrystal are adoptive in a reflective resonator configuration and face-cooled by liquid nitrogen. A maximal Fe:ZnSe laser power of 105 W at a wavelength of 4.1 µm is achieved upon pumping by ten home-made Er:YAG lasers with fiber coupled output working at a frequency of 250 Hz and a pulse duration of ∼420 µs. Corresponding to the maximum Fe:ZnSe laser power, the optical-optical efficiency and slope efficiency with respect to the absorbed pump power are 43% and 44% respectively. The beam quality factor M2 is measured to be 3.4. To the best of our knowledge, it is the highest output average power of an Fe:ZnSe laser reported.

16.
Phys Rev Lett ; 132(16): 166002, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38701470

RESUMEN

Superconductivity has been one of the focal points in medium and high-entropy alloys (MEAs-HEAs) since the discovery of the body-centered cubic (bcc) HEA superconductor in 2014. Until now, the superconducting transition temperature (T_{c}) of most MEA and HEA superconductors has not exceeded 10 K. Here, we report a TaNbHfZr bulk MEA superconductor crystallized in the BCC structure with a T_{c} of 15.3 K which set a new record. During compression, T_{c} follows a dome-shaped curve. It reaches a broad maximum of roughly 15 K at around 70 GPa before decreasing to 9.3 K at 157.2 GPa. First-principles calculations attribute the dome-shaped curve to two competing effects, that is, the enhancement of the logarithmically averaged characteristic phonon frequency ω_{log} and the simultaneous suppression of the electron-phonon coupling constant λ. Thus, TaNbHfZr MEA may have a promising future for studying the underlying quantum physics, as well as developing new applications under extreme conditions.

17.
Eur J Nucl Med Mol Imaging ; 51(2): 434-442, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37789188

RESUMEN

PURPOSE: Presynaptic dopaminergic positron emission tomography (PET) imaging serves as an essential tool in diagnosing and differentiating patients with suspected parkinsonism, including idiopathic Parkinson's disease (PD) and other neurodegenerative and non-neurodegenerative diseases. The PET tracers most commonly used at the present time mainly target dopamine transporters (DAT), aromatic amino acid decarboxylase (AADC), and vesicular monoamine type 2 (VMAT2). However, established standards for the imaging procedure and interpretation of presynaptic dopaminergic PET imaging are still lacking. The goal of this international consensus is to help nuclear medicine practitioners procedurally perform presynaptic dopaminergic PET imaging. METHOD: A multidisciplinary task group formed by experts from various countries discussed and approved the consensus for presynaptic dopaminergic PET imaging in parkinsonism, focusing on standardized recommendations, procedures, interpretation, and reporting. CONCLUSION: This international consensus and practice guideline will help to promote the standardized use of presynaptic dopaminergic PET imaging in parkinsonism. It will become an international standard for this purpose in clinical practice.


Asunto(s)
Enfermedad de Parkinson , Trastornos Parkinsonianos , Humanos , Dopamina/metabolismo , Consenso , Trastornos Parkinsonianos/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Enfermedad de Parkinson/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo
18.
Nat Chem Biol ; 18(8): 894-903, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35681029

RESUMEN

Membrane proteins, including ion channels, receptors and transporters, are often composed of multiple subunits and can form large complexes. Their specific composition in native tissues is difficult to determine and remains largely unknown. In this study, we developed a method for determining the subunit composition of endogenous cell surface protein complexes from isolated native tissues. Our method relies on nanobody-based sensors, which enable proximity detection between subunits in time-resolved Förster resonance energy transfer (FRET) measurements. Additionally, given conformation-specific nanobodies, the activation of these complexes can be recorded in native brain tissue. Applied to the metabotropic glutamate receptors in different brain regions, this approach revealed the clear existence of functional metabotropic glutamate (mGlu)2-mGlu4 heterodimers in addition to mGlu2 and mGlu4 homodimers. Strikingly, the mGlu4 subunits appear to be mainly heterodimers in the brain. Overall, these versatile biosensors can determine the presence and activity of endogenous membrane proteins in native tissues with high fidelity and convenience.


Asunto(s)
Ácido Glutámico , Receptores de Glutamato Metabotrópico , Encéfalo/metabolismo , Transferencia Resonante de Energía de Fluorescencia/métodos , Receptores de Glutamato Metabotrópico/metabolismo
19.
J Magn Reson Imaging ; 59(1): 43-57, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37246343

RESUMEN

Acute kidney injury (AKI) is a frequent complication of critical illness and carries a significant risk of short- and long-term mortality. The prediction of the progression of AKI to long-term injury has been difficult for renal disease treatment. Radiologists are keen for the early detection of transition from AKI to long-term kidney injury, which would help in the preventive measures. The lack of established methods for early detection of long-term kidney injury underscores the pressing needs of advanced imaging technology that reveals microscopic tissue alterations during the progression of AKI. Fueled by recent advances in data acquisition and post-processing methods of magnetic resonance imaging (MRI), multiparametric MRI is showing great potential as a diagnostic tool for many kidney diseases. Multiparametric MRI studies offer a precious opportunity for real-time noninvasive monitoring of pathological development and progression of AKI to long-term injury. It provides insight into renal vasculature and function (arterial spin labeling, intravoxel incoherent motion), tissue oxygenation (blood oxygen level-dependent), tissue injury and fibrosis (diffusion tensor imaging, diffusion kurtosis imaging, T1 and T2 mapping, quantitative susceptibility mapping). The multiparametric MRI approach is highly promising but the longitudinal investigation on the transition of AKI to irreversible long-term impairment is largely ignored. Further optimization and implementation of renal MR methods in clinical practice will enhance our comprehension of not only AKI but chronic kidney diseases. Novel imaging biomarkers for microscopic renal tissue alterations could be discovered and benefit the preventative interventions. This review explores recent MRI applications on acute and long-term kidney injury while addressing lingering challenges, with emphasis on the potential value of the development of multiparametric MRI for renal imaging on clinical systems. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.


Asunto(s)
Lesión Renal Aguda , Imagen de Difusión Tensora , Humanos , Riñón/patología , Imagen por Resonancia Magnética/métodos , Lesión Renal Aguda/patología , Espectroscopía de Resonancia Magnética , Imagen de Difusión por Resonancia Magnética/métodos
20.
Cell Commun Signal ; 22(1): 343, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38907279

RESUMEN

Mitochondria are central to endothelial cell activation and angiogenesis, with the RNA polymerase mitochondrial (POLRMT) serving as a key protein in regulating mitochondrial transcription and oxidative phosphorylation. In our study, we examined the impact of POLRMT on angiogenesis and found that its silencing or knockout (KO) in human umbilical vein endothelial cells (HUVECs) and other endothelial cells resulted in robust anti-angiogenic effects, impeding cell proliferation, migration, and capillary tube formation. Depletion of POLRMT led to impaired mitochondrial function, characterized by mitochondrial depolarization, oxidative stress, lipid oxidation, DNA damage, and reduced ATP production, along with significant apoptosis activation. Conversely, overexpressing POLRMT promoted angiogenic activity in the endothelial cells. In vivo experiments demonstrated that endothelial knockdown of POLRMT, by intravitreous injection of endothelial specific POLRMT shRNA adeno-associated virus, inhibited retinal angiogenesis. In addition, inhibiting POLRMT with a first-in-class inhibitor IMT1 exerted significant anti-angiogenic impact in vitro and in vivo. Significantly elevated expression of POLRMT was observed in the retinal tissues of streptozotocin-induced diabetic retinopathy (DR) mice. POLRMT endothelial knockdown inhibited pathological retinal angiogenesis and mitigated retinal ganglion cell (RGC) degeneration in DR mice. At last, POLRMT expression exhibited a substantial increase in the retinal proliferative membrane tissues of human DR patients. These findings collectively establish the indispensable role of POLRMT in angiogenesis, both in vitro and in vivo.


Asunto(s)
ARN Polimerasas Dirigidas por ADN , Células Endoteliales de la Vena Umbilical Humana , Mitocondrias , Humanos , Animales , Ratones , Mitocondrias/metabolismo , ARN Polimerasas Dirigidas por ADN/metabolismo , ARN Polimerasas Dirigidas por ADN/genética , Retinopatía Diabética/patología , Retinopatía Diabética/metabolismo , Retinopatía Diabética/genética , Ratones Endogámicos C57BL , Proliferación Celular , Neovascularización Patológica/genética , Neovascularización Patológica/metabolismo , Masculino , Neovascularización Fisiológica/genética , Movimiento Celular , Apoptosis , Angiogénesis
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