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1.
Appl Opt ; 63(16): 4414-4420, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38856622

RESUMO

Gallium oxide (G a 2 O 3) photodetectors have drawn increased interest for their widespread applications ranging from military to civil. Due to the inherent oxygen vacancy defects, they seriously suffer from trade-offs that make them incompetent for high-responsivity, quick-response detection. Herein, a G a 2 O 3 nanocavity photodetector assisted with grating electrodes is designed to break the constraint. The proposed structure supports both the plasmonic mode and the Fabry-Perot (F-P) mode. Numerical calculations show that the absorption of 99.8% is realized for ultra-thin G a 2 O 3 (30 nm), corresponding to a responsivity of 12.35 A/W. Benefiting from optical mechanisms, the external quantum efficiency (EQE) reaches 6040%, which is 466 times higher than that of bare G a 2 O 3 film. Furthermore, the proposed photodetector achieves a polarization-dependent dichroism ratio of 9.1, enabling polarization photodetection. The grating electrodes also effectively reduce the transit time of the photo-generated carriers. Our work provides a sophisticated platform for developing high-performance G a 2 O 3 photodetectors with the advantages of simplified fabrication processes and multidimensional detection.

2.
Anal Chem ; 94(36): 12472-12480, 2022 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-36044263

RESUMO

N-Acylethanolamines (NAE) are a class of essential signaling lipids that are involved in a variety of physiological processes, such as energy homeostasis, anti-inflammatory responses, and neurological functions. NAE lipids are functionally different yet structurally similar and often have low concentrations in biological systems. Therefore, the comprehensive analysis of NAE lipids in complex biological matrices is very challenging. In this work, we developed an ion mobility-mass spectrometry (IM-MS) based four-dimensional (4D) untargeted technology for comprehensive analysis of NAE lipids. First, we employed the picolinyl derivatization to significantly improve ionization sensitivity of NAE lipids by 2-9-fold. Next, we developed a two-step quantitative structure-retention relationship (QSRR) strategy and used the AllCCS software to curate a 4D library for 170 NAE lipids with information on m/z, retention time, collision cross-section, and MS/MS spectra. Then, we developed a 4D untargeted technology empowered by the 4D library to support unambiguous identifications of NAE lipids. Using this technology, we readily identified a total of 68 NAE lipids across different biological samples. Finally, we used the 4D untargeted technology to comprehensively quantify 47 NAE lipids in 10 functional regions in the mouse brain and revealed a broad spectrum of the age-associated changes in NAE lipids across brain regions. We envision that the comprehensive analysis of NAE lipids will strengthen our understanding of their functions in regulating distinct physiological activities.


Assuntos
Espectrometria de Mobilidade Iônica , Espectrometria de Massas em Tandem , Animais , Encéfalo , Etanolaminas , Espectrometria de Mobilidade Iônica/métodos , Lipídeos/análise , Camundongos
3.
Ecotoxicol Environ Saf ; 241: 113844, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36068766

RESUMO

Heavy metals are a group of anthropogenic contaminants in estuary ecosystems. Bacteria in estuaries counteract the highly concentrated metal toxicity through metal resistance genes (MRGs). Presently, metagenomic technology is popularly used to study MRGs. However, an easier and less expensive method of acquiring MRG information is needed to deepen our understanding of the fate of MRGs. Thus, this study explores the feasibility of using a machine learning approach-namely, random forests (RF)-to predict MRG abundance based on the 16S rRNA amplicon sequenced datasets from subtropical estuaries in China. Our results showed that the total MRG abundance could be predicted by RF models using bacterial composition at different taxonomic levels. Among them, the relative abundance of bacterial phyla had the highest predicted accuracy (71.7 %). In addition, the RF models constructed by bacterial phyla predicted the abundance of six MRG types and nine MRG subtypes with substantial accuracy (R2 > 0.600). Five bacterial phyla (Firmicutes, Bacteroidetes, Patescibacteria, Armatimonadetes, and Nitrospirae) substantially determined the variations in MRG abundance. Our findings prove that RF models can predict MRG abundance in South China estuaries during the wet season by using the bacterial composition obtained by 16S rRNA amplicon sequencing.


Assuntos
Estuários , Metais Pesados , Bactérias/genética , Ecossistema , Genes Bacterianos , Aprendizado de Máquina , Metais Pesados/análise , Metais Pesados/toxicidade , RNA Ribossômico 16S/genética
4.
Opt Express ; 28(2): 821-845, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32121805

RESUMO

The problem of X-ray diffraction from multilayer-coated blazed diffraction gratings is analyzed. Invalidity of the conventional condition of maximal diffraction efficiency observed in previous experiments is explained theoretically. This is attributed to two factors: contribution of anti-blaze facets to diffraction efficiency and effect of strongly asymmetric diffraction. We demonstrate that a proper choice of the multilayer d-spacing allows to design grating with the diffraction efficiency close to the maximal possible one throughout the tender X-ray range (E∼1-5 keV). An optimization procedure is suggested for the first time to choose the optimal grating parameters and the operation diffraction order to obtain a high fix-focus constant and high diffraction efficiency simultaneously in a wide spectral range.

5.
J Biol Chem ; 293(38): 14880-14890, 2018 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-30076220

RESUMO

αB-Crystallin (αBc) is a small heat shock protein that protects cells against abnormal protein aggregation and disease-related degeneration. αBc is also a major structural protein that forms polydisperse multimers that maintain the liquid-like property of the eye lens. However, the relationship and regulation of the two functions have yet to be explored. Here, by combining NMR spectroscopy and multiple biophysical approaches, we found that αBc uses a conserved ß4/ß8 surface of the central α-crystallin domain to bind α-synuclein and Tau proteins and prevent them from aggregating into pathological amyloids. We noted that this amyloid-binding surface can also bind the C-terminal IPI motif of αBc, which mediates αBc multimerization and weakens its chaperone activity. We further show that disruption of the IPI binding impairs αBc self-multimerization but enhances its chaperone activity. Our work discloses the structural mechanism underlying the regulation of αBc chaperone activity and self-multimerization and sheds light on the different functions of αBc in antagonizing neurodegeneration and maintaining eye lens liquidity.


Assuntos
Amiloide/metabolismo , Chaperonas Moleculares/metabolismo , Multimerização Proteica , Cadeia B de alfa-Cristalina/metabolismo , Ligação Competitiva , Fenômenos Biofísicos , Humanos , Chaperonas Moleculares/química , Ressonância Magnética Nuclear Biomolecular , Cadeia B de alfa-Cristalina/química , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo
6.
Antimicrob Agents Chemother ; 60(9): 5573-80, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27401566

RESUMO

Nephrotoxicity is a relevant limitation of gentamicin, and obese patients have an increased risk for gentamicin-induced kidney injury. This damage is thought to depend on the accumulation of the drug in the renal cortex. Obese rats showed substantially higher levels of gentamicin in the kidney than did lean animals. This study characterized the role of organic cation transporters (OCTs) in gentamicin transport and elucidated their possible contribution in the increased renal accumulation of gentamicin in obesity. The mRNA and protein expression levels of the organic cation transporters Oct2 (Slc22a2) and Oct3 (Slc22a3) were increased in kidney samples from obese mice fed a high-fat diet. Similarly, OCT2 (∼2-fold) and OCT3 (∼3-fold) showed increased protein expression in the kidneys of obese patients compared with those of nonobese individuals. Using HEK293 cells overexpressing the different OCTs, human OCT2 was found to transport [(3)H]gentamicin with unique sigmoidal kinetics typical of homotropic positive cooperativity (autoactivation). In mouse primary proximal tubular cells, [(3)H]gentamicin uptake was reduced by approximately 40% when the cells were coincubated with the OCT2 substrate metformin. The basolateral localization of OCT2 suggests that gentamicin can enter proximal tubular cells from the blood side, probably as part of a slow tubular secretion process that may influence intracellular drug concentrations and exposure time. Increased expression of OCT2 may explain the higher accumulation of gentamicin, thereby conferring an increased risk of renal toxicity in obese patients.


Assuntos
Gentamicinas/efeitos adversos , Nefropatias/induzido quimicamente , Nefropatias/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Animais , Linhagem Celular , Dieta Hiperlipídica , Feminino , Gentamicinas/farmacologia , Células HEK293 , Humanos , Cinética , Masculino , Metformina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Obesidade/metabolismo , RNA Mensageiro/metabolismo
7.
Brain ; 138(Pt 3): 726-35, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25595147

RESUMO

Post-traumatic sleep-wake disturbances are common after acute traumatic brain injury. Increased sleep need per 24 h and excessive daytime sleepiness are among the most prevalent post-traumatic sleep disorders and impair quality of life of trauma patients. Nevertheless, the relation between traumatic brain injury and sleep outcome, but also the link between post-traumatic sleep problems and clinical measures in the acute phase after traumatic brain injury has so far not been addressed in a controlled and prospective approach. We therefore performed a prospective controlled clinical study to examine (i) sleep-wake outcome after traumatic brain injury; and (ii) to screen for clinical and laboratory predictors of poor sleep-wake outcome after acute traumatic brain injury. Forty-two of 60 included patients with first-ever traumatic brain injury were available for follow-up examinations. Six months after trauma, the average sleep need per 24 h as assessed by actigraphy was markedly increased in patients as compared to controls (8.3 ± 1.1 h versus 7.1 ± 0.8 h, P < 0.0001). Objective daytime sleepiness was found in 57% of trauma patients and 19% of healthy subjects, and the average sleep latency in patients was reduced to 8.7 ± 4.6 min (12.1 ± 4.7 min in controls, P = 0.0009). Patients, but not controls, markedly underestimated both excessive sleep need and excessive daytime sleepiness when assessed only by subjective means, emphasizing the unreliability of self-assessment of increased sleep propensity in traumatic brain injury patients. At polysomnography, slow wave sleep after traumatic brain injury was more consolidated. The most important risk factor for developing increased sleep need after traumatic brain injury was the presence of an intracranial haemorrhage. In conclusion, we provide controlled and objective evidence for a direct relation between sleep-wake disturbances and traumatic brain injury, and for clinically significant underestimation of post-traumatic sleep-wake disturbances by trauma patients.


Assuntos
Lesões Encefálicas/complicações , Distúrbios do Sono por Sonolência Excessiva/etiologia , Distúrbios do Início e da Manutenção do Sono/etiologia , Actigrafia , Adulto , Análise de Variância , Lesões Encefálicas/psicologia , Ritmo Circadiano/fisiologia , Avaliação da Deficiência , Distúrbios do Sono por Sonolência Excessiva/diagnóstico , Epinefrina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polissonografia , Estudos Prospectivos , Estudos Retrospectivos , Proteínas S100/metabolismo , Distúrbios do Início e da Manutenção do Sono/diagnóstico
8.
ACS Appl Mater Interfaces ; 16(24): 31322-31331, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38857900

RESUMO

Metal halide-based broadband near-infrared (NIR) luminescent materials face problems such as complicated preparation, high cost, low photoluminescence quantum yield, and high excitation energy. Here, incorporating Sb3+ and Br- into (C20H20P)2ZnCl4 crystals allowed for the achievement of efficient broadband near-infrared emission under 400 nm excitation while maintaining satisfactory environmental and thermal stability. The compounds exhibit a broad range of emission bands from 550 to 1050 nm, with a photoluminescence quantum yield of 93.57%. This is a groundbreaking achievement for organic-inorganic hybrid metal halide NIR luminescent materials. The near-infrared emission is suggested to originate from [SbX5]2-, as supported by the femtosecond transient absorption spectra and density-functional theory calculations. This phosphor-based NIR LEDs successfully demonstrate potential applications in night vision, medical imaging, information encryption, and anticounterfeiting.

9.
Mater Horiz ; 11(9): 2230-2241, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38421281

RESUMO

Recently, organic Sb(III)-based metal halides have achieved significant results in the visible light region due to their efficient emission. However, realizing efficient broadband near-infrared (NIR) emission in such materials is a great challenge. Herein, we developed three different NIR emitters via a coordination structure modulation strategy in Sb3+-doped zero-dimensional organic metal chlorides of (C20H20P)2MnCl4, (C20H20P)2ZnCl4, and (C20H20P)2CdCl4 with tetrahedral structure. More specifically, after the dopant Sb3+ is inserted into the host lattice, the coordination structures of Sb3+ ions can change from [SbCl5]2- square-pyramidal configuration to [SbCl4]- clusters, which will bring a larger lattice distortion degree to the excited state compared to the ground state, resulting in a larger Stokes shift. Thus, efficient NIR emission with near-unity photoluminescence quantum yield (PLQY) can be obtained in Sb3+-doped compounds under 365 nm excitation. Moreover, Sb3+-doped NIR emitters also show remarkable stabilities, which prompts us to fabricate NIR phosphor conversion light-emitting diodes (pc-LEDs) and demonstrate their application in night vision. More interestingly, the Sb3+-doped (C20H20P)2MnCl4 shows tunable emission characteristics, which can be tuned from green to greenish-yellow, orange, red, and NIR emission under different external stimuli, and thus we can demonstrate the applications of this compound in quintuple-mode fluorescence anti-counterfeiting and information encryption.

10.
EMBO Mol Med ; 16(2): 334-360, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38177537

RESUMO

Cancer immunotherapies have achieved unprecedented success in clinic, but they remain largely ineffective in some major types of cancer, such as colorectal cancer with microsatellite stability (MSS CRC). It is therefore important to study tumor microenvironment of resistant cancers for developing new intervention strategies. In this study, we identify a metabolic cue that determines the unique immune landscape of MSS CRC. Through secretion of distal cholesterol precursors, which directly activate RORγt, MSS CRC cells can polarize T cells toward Th17 cells that have well-characterized pro-tumor functions in colorectal cancer. Analysis of large human cancer cohorts revealed an asynchronous pattern of the cholesterol biosynthesis in MSS CRC, which is responsible for the abnormal accumulation of distal cholesterol precursors. Inhibiting the cholesterol biosynthesis enzyme Cyp51, by pharmacological or genetic interventions, reduced the levels of intratumoral distal cholesterol precursors and suppressed tumor progression through a Th17-modulation mechanism in preclinical MSS CRC models. Our study therefore reveals a novel mechanism of cancer-immune interaction and an intervention strategy for the difficult-to-treat MSS CRC.


Assuntos
Neoplasias Colorretais , Instabilidade de Microssatélites , Humanos , Neoplasias Colorretais/genética , Microambiente Tumoral
11.
Microbiol Spectr ; 11(1): e0368322, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-36507672

RESUMO

Microbial communities in coastal waters are diverse and dynamic and play important roles in ecosystem functions and services. Despite the ecological impact of bacterioplankton or pathogens, little is known about whether bacterioplankton and pathogen communities exhibit similar patterns. Here, using 16S RNA gene amplicon sequencing, the geographic patterns and assembly processes of bacterioplankton and pathogen communities in 30 subtropical estuaries were studied. Results showed that the estuarine bacterioplankton communities mainly consisted of Proteobacteria (49.06%), Actinobacteria (17.62%), and Bacteroidetes (16.33%), among which 31 pathogen genera (186 amplicon sequence variants [ASVs]) were identified. Under the influence of salinity, bacterioplankton and pathogens showed similar biogeographic patterns. Redundancy and correlation analyses indicated that the bacterioplankton communities were strongly correlated with estuarine environmental factors, but potential pathogens were less influenced. Co-occurrence network analysis revealed a close relationship between bacterioplankton and potential pathogens, with two pathogens identified as connectors (i.e., ASV340 [Clostridium perfringens] and ASV1624 [Brevundimonas diminuta]), implying potential impacts of pathogens on structure, function, and stability of estuarine bacterioplankton communities. Null-model analysis revealed that deterministic processes (heterogeneous selection) dominated bacterioplankton community assembly, while stochastic processes (undominated effect) shaped the potential pathogen community. Our findings illustrate the biogeographic patterns and community assembly mechanisms of bacterioplankton and pathogens in estuaries, which should provide guidance and a reference for the control of potential pathogenic bacteria. IMPORTANCE Bacterioplankton play an important role in estuarine ecosystem functions and services; however, potentially pathogenic bacteria may exhibit infectivity and pose a serious threat to environmental and human health. In this study, geographic patterns and assembly processes of bacterioplankton communities in 30 subtropical estuaries were explored, and potential pathogenic bacteria in the estuaries were detected and profiled. Our results demonstrate here that bacterioplankton and pathogens show similar biogeographic patterns under the influence of salinity. Interestingly, heterogeneous selection dominated bacterioplankton assembly, while stochasticity dominated pathogen assembly. This study provides important information for future risk assessment of potential pathogenic bacteria as well as management in estuarine ecosystems.


Assuntos
Ecossistema , Microbiota , Humanos , Estuários , Microbiota/genética , Bactérias/genética , Proteobactérias , Organismos Aquáticos
12.
Small Methods ; 7(1): e2201382, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36446642

RESUMO

The combination of near edge X-ray absorption spectroscopy with nanoscale X-ray imaging is a powerful analytical tool for many applications in energy technologies, catalysis, which are critical to combat climate change, as well as microelectronics and life science. Materials from these scientific areas often contain key elements, such as Si, P, S, Y, Zr, Nb, and Mo as well as lanthanides, whose X-ray absorption edges lie in the so-called tender photon energy range 1.5-5.0 keV. Neither conventional grazing incidence grating nor crystal monochromators have high transmission in this energy range, thereby yielding the tender photon energy gap. To close this gap, a monochromator setup based on a multilayer coated blazed plane grating and plane mirror is devised. The measurements show that this novel concept improves the photon flux in the tender X-ray regime by two-orders-of-magnitude enabling previously unattainable laboratory and synchrotron-based studies. This setup is applied to perform nanoscale spectromicroscopy studies. The high photon flux provides sufficient sensitivity to obtain the electronic structure of Mo in platinum-free MoNi4 nanoparticles for electrochemical energy conversion. Additionally, it is shown that the chemical bonding of nano-structures in integrated circuits can be distinguished by the electronic configuration at the Si-K edge.

13.
Cancer Cell ; 41(7): 1276-1293.e11, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37244259

RESUMO

The concept of targeting cholesterol metabolism to treat cancer has been widely tested in clinics, but the benefits are modest, calling for a complete understanding of cholesterol metabolism in intratumoral cells. We analyze the cholesterol atlas in the tumor microenvironment and find that intratumoral T cells have cholesterol deficiency, while immunosuppressive myeloid cells and tumor cells display cholesterol abundance. Low cholesterol levels inhibit T cell proliferation and cause autophagy-mediated apoptosis, particularly for cytotoxic T cells. In the tumor microenvironment, oxysterols mediate reciprocal alterations in the LXR and SREBP2 pathways to cause cholesterol deficiency of T cells, subsequently leading to aberrant metabolic and signaling pathways that drive T cell exhaustion/dysfunction. LXRß depletion in chimeric antigen receptor T (CAR-T) cells leads to improved antitumor function against solid tumors. Since T cell cholesterol metabolism and oxysterols are generally linked to other diseases, the new mechanism and cholesterol-normalization strategy might have potential applications elsewhere.


Assuntos
Antineoplásicos , Neoplasias , Oxisteróis , Humanos , Colesterol/metabolismo , Ativação Linfocitária , Imunoterapia Adotiva , Microambiente Tumoral
14.
Anal Chim Acta ; 1142: 108-117, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33280688

RESUMO

Sterols are an important type of lipids, and play many important roles in physiological and pathological processes. However, comprehensive analysis of sterols especially identification of unknown sterols is challenging. In this work, LC-MS with all ion fragmentation (AIF) technology was developed for untargeted analysis of sterols in biological samples. AIF technology provided holistic and multi-dimensional characterization for both knowns and unknowns sterols, including accurate m/z, isotope pattern, retention time (RT), and co-eluted peak profiles between MS1 and MS2 ions in one analysis. We further developed an analysis strategy by integrating the multi-dimensional properties to support unambiguous identification of sterols, including distinguishing sterol isomers. The developed strategy enabled to identify a total of 23 sterols in mouse samples, and quantified 19 sterols in mouse liver tissues. More importantly, we demonstrated that AIF based multi-dimensional analysis provided a possibility to identify sterols without chemical standards and facilitated to discover novel compounds with sterol-like structures in biological samples. In summary, we employed the LC-MS based AIF technology to develop multi-dimensional characterization and identification of both known and unknown sterols in complex biological samples. The comprehensive analysis of sterols facilitates to provide molecular insights to many physiological and pathological activities in biology.


Assuntos
Esteróis , Espectrometria de Massas em Tandem , Animais , Cromatografia Líquida , Íons , Camundongos , Tecnologia
15.
Genes (Basel) ; 12(7)2021 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-34199012

RESUMO

The YABBY family of plant-specific transcription factors play important regulatory roles during the development of leaves and floral organs, but their functions in Brassica species are incompletely understood. Here, we identified 79 YABBY genes from Arabidopsis thaliana and five Brassica species (B. rapa, B. nigra, B. oleracea, B. juncea, and B. napus). A phylogenetic analysis of YABBY proteins separated them into five clusters (YAB1-YAB5) with representatives from all five Brassica species, suggesting a high degree of conservation and similar functions within each subfamily. We determined the gene structure, chromosomal location, and expression patterns of the 21 BnaYAB genes identified, revealing extensive duplication events and gene loss following polyploidization. Changes in exon-intron structure during evolution may have driven differentiation in expression patterns and functions, combined with purifying selection, as evidenced by Ka/Ks values below 1. Based on transcriptome sequencing data, we selected nine genes with high expression at the flowering stage. qRT-PCR analysis further indicated that most BnaYAB family members are tissue-specific and exhibit different expression patterns in various tissues and organs of B. napus. This preliminary study of the characteristics of the YABBY gene family in the Brassica napus genome provides theoretical support and reference for the later functional identification of the family genes.


Assuntos
Brassica napus/genética , Evolução Molecular , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Mapeamento Cromossômico , Sequência Conservada/genética , Regulação da Expressão Gênica de Plantas/genética , Genoma de Planta/genética , Família Multigênica/genética , Transcriptoma/genética
16.
Materials (Basel) ; 14(5)2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-33803440

RESUMO

B4C/Pd multilayers with small d-spacing can easily degrade in the air, and the exact degradation process is not clear. In this work, we studied the chemical modification of B4C films and B4C/Pd double layers stored in four different environments: a dry nitrogen environment, the atmosphere, a dry oxygen-rich environment, and a wet nitrogen environment. The XANES spectra of the B4C/Pd layers placed in a dry oxygen-rich environment showed the most significant decrease in the σ* states of the B-C bonds and an increase in the π* states of the B-O bonds compared with the other samples. X-ray photoelectron spectroscopy (XPS) measurements of the samples placed in a dry oxygen-rich environment showed more intensive B-O binding signals in the B4C/Pd layers than in the single B4C film. The results of the Fourier-transform infrared spectroscopy (FTIR) showed a similar decrease in the B-C bonds and an increase in the B-O bonds in the B4C/Pd layers in contrast to the single B4C film placed in a dry oxygen-rich environment. We concluded that the combination of palladium catalysis and the high content of oxygen in the environment promoted the oxidization of boron, deteriorated the B4C composition.

17.
Nat Commun ; 12(1): 4343, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267224

RESUMO

Aberrant sterol lipid metabolism is associated with physiological dysfunctions in the aging brain and aging-dependent disorders such as neurodegenerative diseases. There is an unmet demand to comprehensively profile sterol lipids spatially and temporally in different brain regions during aging. Here, we develop an ion mobility-mass spectrometry based four-dimensional sterolomics technology leveraged by a machine learning-empowered high-coverage library (>2000 sterol lipids) for accurate identification. We apply this four-dimensional technology to profile the spatially resolved landscapes of sterol lipids in ten functional regions of the mouse brain, and quantitatively uncover ~200 sterol lipids uniquely distributed in specific regions with concentrations spanning up to 8 orders of magnitude. Further spatial analysis pinpoints age-associated differences in region-specific sterol lipid metabolism, revealing changes in the numbers of altered sterol lipids, concentration variations, and age-dependent coregulation networks. These findings will contribute to our understanding of abnormal sterol lipid metabolism and its role in brain diseases.


Assuntos
Química Encefálica , Encéfalo/metabolismo , Lipídeos/química , Esteróis/análise , Envelhecimento/fisiologia , Animais , Feminino , Isomerismo , Lipidômica/métodos , Lipídeos/análise , Aprendizado de Máquina , Camundongos Endogâmicos C57BL , Esteróis/química , Esteróis/metabolismo , Espectrometria de Massas em Tandem/métodos
18.
Anal Chim Acta ; 1136: 115-124, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33081935

RESUMO

Lipids are an important class of biomolecules, and play many essential functions in biology. Ion mobility-mass spectrometry (IM-MS) has emerged as a promising technology for lipidomics by providing a holistic and multi-dimensional characterization of lipid structures. However, the lipid identification using the multi-dimensional match (i.e., MS1, retention time, collision cross section, and MS/MS spectra) gives multiple lipid candidates, and often over-reports the structural information. Here, we developed a lipid identification strategy that integrated library-based match and rule-based refinement for accurate lipid structural elucidation in IM-MS based lipidomics. The new strategy took the advantage of multi-dimensional information for high-coverage identification, while it also utilized the fragmentation rules to determine the accurate structural information. We demonstrated that the combined strategy accurately determined the lipid structures as lipid species level, fatty acyl level, or fatty acyl position level for different lipid classes in the lipid standard mixture and various biological samples. The combined strategy efficiently reduced the redundancy and improved the accuracy for different lipid classes, and identified a total of 440-960 lipid species in various biological samples. Finally, we performed quantitative lipidomics analysis of NIST SRM 1950 human plasma using IM-MS technology. The measured concentrations of most quantified lipids (>80%) were highly consistent with values reported from other independent laboratories. In summary, the developed lipid identification strategy allowed for the accurate identification of lipid structures, and facilitated accurate lipid quantification in IM-MS based untargeted lipidomics.


Assuntos
Lipidômica , Espectrometria de Massas em Tandem , Humanos , Espectrometria de Mobilidade Iônica , Lipídeos
19.
Transl Neurodegener ; 7: 25, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30356861

RESUMO

BACKGROUND: Parkinson's disease (PD) is a neurodegenerative disease characterized by intraneuronal Lewy Body (LB) aggregates composed of misfolded alpha-synuclein (α-syn). The spread of misfolded α-syn follows a typical pattern: starting in the olfactory bulb (OB) and the gut, this pathology is followed by the progressive invasion of misfolded α-syn to the posterior part of the brain. It is unknown whether the administration of human mutant alpha-synuclein (hm-α-syn, a human mutation which occurs in familial PD) into the OB of rats would trigger similar α-syn propagation and subsequently cause pathological changes in broader brain fields associated to PD and establish an animal model of prodromal PD. METHODS: hm-α-syn was overexpressed in the OB of rats with an AAV injection. Then motor and non-motor symptoms of the SD rats were tested in different behavioral tasks following the AAV injection. In follow-up studies, pathological mechanisms of α-syn spread were explored at the histological, biochemical and micro-structure levels. RESULTS: The experimental results indicated that hm-α-syn was overexpressed in the OB 3 weeks after the AAV injection. 1) overexpression of the Hm-α-syn in the OB by the AAV injection could transfer to wider adjacent fields beyond the monosynaptic scope. 2) The number of tyrosine hydroxylase positive cells body and fibers was decreased in the substantia nigra (SN) 12 weeks after AAV injection. This was consistent with decreased levels of the DA neurotransmitter. Importantly, behavioral dysfunctions were found that included olfactory impairment after 3 weeks, motor ability impairment and decreased muscular coordination on a rotarod 6 weeks after the AAV injection.3) The morphological level studies found that the Golgi staining revealed the number of neuronal branches and synapses in the OB, prefrontal cortex (PFC), hippocampus (Hip) and striatum caudate putamen (CPU) were decreased. 4) phosphorylated α-syn, at Ser-129 (pSer129), was found to be increased in hm-α-syn injected animals in comparison to controls that overexpressed GFP alone, which was also found in the most of LB stained by the thioflavine S (ThS) in the SN field. 5) A marker of autophagy (LC3B) was increased in serval fields, which was colacolizated with a marker of apoptosis in the SN field. CONCLUSIONS: These results demonstrate that expression of exogenous mutant α-syn in the OB induces pathological changes in the sensitive brain fields by transferring pathogenic α-syn to adjacent fields. This method may be useful for establishing an animal model of prodromal PD.

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