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1.
bioRxiv ; 2024 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-38464093

RESUMO

The coacervation and structural rearrangement of the protein alpha-synuclein (αSyn) into cytotoxic oligomers and amyloid fibrils are considered pathological hallmarks of Parkinson's disease. While aggregation is recognized as the key element of amyloid diseases, liquid-liquid phase separation (LLPS) and its interplay with aggregation have gained increasing interest. Previous work showed that factors promoting or inhibiting amyloid formation have similar effects on phase separation. Here, we provide a detailed scanning of a wide range of parameters including protein, salt and crowding concentrations at multiple pH values, revealing different salt dependencies of aggregation and phase separation. The influence of salt on aggregation under crowded conditions follows a non-monotonic pattern, showing increased effects at medium salt concentrations. This behavior can be elucidated through a combination of electrostatic screening and salting-out effects on the intramolecular interactions between the N-terminal and C-terminal regions of αSyn. By contrast, we find a monotonic salt dependence of phase separation due to the intermolecular interaction. Furthermore, we observe the time evolution of the two distinct assembly states, with macroscopic fibrillar-like bundles initially forming at medium salt concentration but subsequently converting into droplets after prolonged incubation. The droplet state is therefore capable of inhibiting aggregation or even dissolving the aggregates through a variety of heterotypic interactions, thus preventing αSyn from its dynamically arrested state.

2.
ACS Chem Neurosci ; 15(1): 98-107, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38096481

RESUMO

Prion diseases are fatal neurodegenerative disorders characterized by the conversion of the cellular prion protein (PrPC) into a misfolded prion form, which is believed to disrupt the cellular membranes. However, the exact mechanisms underlying prion toxicity, including the formation of membrane pores, are not fully understood. The prion protein consists of two domains: a globular domain (GD) and a flexible N-terminus (FT) domain. Although a proximal polybasic amino acid (FT(23-31) sequence of FT is a prerequisite for cellular membrane permeabilization, other functional domain regions may modulate its effects. Through single-channel electrical recordings and cryo-electron microscopy (cryo-EM), we discovered that the FT(23-50) fragment forms pore-shaped oligomers and plays a dominant role in membrane permeabilization within the full-length mouse prion protein (mPrP(23-230)). In contrast, the FT(51-110) domain or the C-terminal domain downregulate the channel activity of FT(23-50) and mPrP(23-230). The addition of prion mimetic antibody, POM1 significantly amplifies mPrP(23-230) membrane permeabilization, whereas POM1_Y104A, a mutant that binds to PrP but cannot elicit toxicity, has a negligible effect on membrane permeabilization. Additionally, the anti-N-terminal antibody POM2 or Cu2+ binds to the FT domain, subsequently enhancing the FT(23-110) channel activity. Importantly, our setup provides a novel approach without an external fused protein to examine the channel activity of truncated PrP in the lipid membranes. We therefore propose that the primary N-terminal residues are essential for membrane permeabilization, while other functional segments of PrP play a vital role in modulating the pathological effects of PrP-mediated neurotoxicity.


Assuntos
Proteínas PrPC , Doenças Priônicas , Príons , Camundongos , Animais , Príons/metabolismo , Proteínas Priônicas/genética , Microscopia Crioeletrônica , Membrana Celular/metabolismo , Anticorpos , Proteínas PrPC/química
3.
Environ Technol ; : 1-14, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38084652

RESUMO

Combining mine exhaust waste heat with existing heat pump technology is a promising technical route to realise the efficient extraction and scientific use of low-grade waste heat resources in mines and to solve the problem of insufficient heat supply in remote mining areas. This study proposes a new type of mine-exhaust-air heat exchange coupled with heat-pump waste-heat-utilisation system based on deep enthalpy heat extraction. Using a mining area in Northwest China as a representative case, this study establishes a systematic exergy analytical model and a thermo-economic model. Through an in-depth analysis of the different evaporation temperatures and condensing temperatures, the system's energy efficiency ratio (COP) reaches its optimal performance, with the total exergy efficiency surpassing 90%. The minimum efficiency of the subsystem return air heat exchanger is 35%. The unit thermal costs of the mine exhaust air waste heat utilisation system and a conventional coal-fired boiler system are 0.1291 and 0.1573 million RMB/kW·h, respectively. This is a thermal economics cost saving of 21%. The studied system demonstrates great economic viability and the potential for energy saving throughout its life cycle.

4.
bioRxiv ; 2023 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-37745313

RESUMO

Acute kidney injury (AKI) is an important contributor to the development of chronic kidney disease (CKD). There is a need to understand molecular mediators that drive either recovery or progression to CKD. In particular, the role of miRNA and its regulatory role in AKI is poorly understood. We performed miRNA and mRNA sequencing on biobanked human kidney tissues obtained in the routine clinical care of patients with the diagnoses of AKI and minimal change disease (MCD), in addition to nephrectomized (Ref) tissue from individuals without known kidney disease. Transcriptomic analysis of mRNA revealed that Ref tissues exhibited a similar injury signature to AKI, not identified in MCD samples. The transcriptomic signature of human AKI was enriched with genes in pathways involved in cell adhesion and epithelial-to-mesenchymal transition (e.g., CDH6, ITGB6, CDKN1A ). miRNA DE analysis revealed upregulation of miRNA associated with immune cell recruitment and inflammation (e.g., miR-146a, miR-155, miR-142, miR-122). These miRNA (i.e., miR-122, miR-146) are also associated with downregulation of mRNA such as DDR2 and IGFBP6 , respectively. These findings suggest integrated interactions between miRNAs and target mRNAs in AKI-related processes such as inflammation, immune cell activation and epithelial-to-mesenchymal transition. These data contribute several novel findings when describing the epigenetic regulation of AKI by miRNA, and also underscores the importance of utilizing an appropriate reference control tissue to understand canonical pathway alterations in AKI.

5.
Front Pharmacol ; 14: 1227470, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37680714

RESUMO

Objectives: Aficamten is a selective, small-molecule allosteric inhibitor of cardiac sarcomere being developed as a chronic oral treatment for patients with symptomatic obstructive hypertrophic cardiomyopathy. This was the first-in-Chinese study aiming to investigate the safety, tolerability, pharmacokinetics, and pharmacodynamics of aficamten in healthy adults. Methods: This double-blind, randomized, placebo-controlled, phase 1 study was conducted in 28 healthy male and female Chinese participants after single ascending dose (SAD) and multi-dose (MD) administrations of aficamten. In the SAD cohort, 16 participants were randomized to receive a single oral dose of aficamten: 10 mg, 20 mg, or placebo. In the MD cohort, 12 participants were randomized to receive multiple doses of aficamten: 5 mg or placebo once daily for 14 days. Safety was monitored throughout the study with electrocardiograms, echocardiograms, clinical laboratory tests, and reporting of adverse events (AEs). Pharmacokinetic profiles of aficamten and metabolites, as well as CYP2D6 genetic impact, were evaluated. Results: A total of 35 treatment-emergent AEs were reported by 14 (50%) participants with mild severity. There were no serious AEs or adverse decreases in left ventricular ejection fraction below 50% during the study. Aficamten was dose-proportional over the dose range of 5-20 mg and accumulated in the MD cohort. Conclusion: Aficamten was safe and well-tolerated in the healthy Chinese adult participants. The pharmacokinetics of aficamten in the Chinese population was comparable to those previously found in Western participants. These phase 1 data support the progression of aficamten into future clinical studies in Chinese patients. Clinical Trial registration: https://clinicaltrials.gov, identifier: NCT04783766.

6.
Sci Rep ; 13(1): 12701, 2023 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-37543648

RESUMO

Machine learning applied to digital pathology has been increasingly used to assess kidney function and diagnose the underlying cause of chronic kidney disease (CKD). We developed a novel computational framework, clustering-based spatial analysis (CluSA), that leverages unsupervised learning to learn spatial relationships between local visual patterns in kidney tissue. This framework minimizes the need for time-consuming and impractical expert annotations. 107,471 histopathology images obtained from 172 biopsy cores were used in the clustering and in the deep learning model. To incorporate spatial information over the clustered image patterns on the biopsy sample, we spatially encoded clustered patterns with colors and performed spatial analysis through graph neural network. A random forest classifier with various groups of features were used to predict CKD. For predicting eGFR at the biopsy, we achieved a sensitivity of 0.97, specificity of 0.90, and accuracy of 0.95. AUC was 0.96. For predicting eGFR changes in one-year, we achieved a sensitivity of 0.83, specificity of 0.85, and accuracy of 0.84. AUC was 0.85. This study presents the first spatial analysis based on unsupervised machine learning algorithms. Without expert annotation, CluSA framework can not only accurately classify and predict the degree of kidney function at the biopsy and in one year, but also identify novel predictors of kidney function and renal prognosis.


Assuntos
Redes Neurais de Computação , Insuficiência Renal Crônica , Humanos , Algoritmos , Aprendizado de Máquina , Insuficiência Renal Crônica/diagnóstico , Análise por Conglomerados
7.
Environ Sci Pollut Res Int ; 30(45): 100584-100595, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37639087

RESUMO

Fine particulate matter (PM2.5) seriously affects environmental air quality and human health, and antibiotic resistance genes (ARGs) in PM2.5 posed a great challenge to clinical medicine. The year of 2013-2017 was an important 5-year period for the implementation of Air Pollution Prevention and Control Action Plan (APPCAP) in China. Here, we took Handan, a PM2.5 polluted city in northern China, as the research object and analyzed ARGs in PM2.5 in winter (January) from 2013 to 2017. The results showed that the abundance of ARGs was the highest in 2013 (3.7 × 10-2 copies/16S rRNA), and ARGs were positively correlated with air quality index (AQI) (r = 0.328, P < 0.05) and PM2.5 concentration (r = 0.377, P = 0.020 < 0.05) in the 5-year period. The ARGs carried by PM2.5 in four functional regions of sewage treatment plant, steel works, university, and park showed that sul1 and qepA had higher abundance in each functional region, and the total ARG abundance in sewage treatment plant (1.3 × 10-1 copies/16S rRNA) was the highest, while lowest in park (2.0 × 10-3 copies/16S rRNA). Potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) model were used to trace the pollutants at the sampling points, which indicated that the surrounding cities contributed more than quarter to the sampling points. Therefore, regional transportation reduces the spatial distribution difference of ARGs in PM2.5. The exposure dose of ARGs in different functional regions illustrated that the total inhaled dose of ARGs in sewage treatment plant (1.7 × 105 copies/d) was the highest, while lowest in park (3.2 × 104 copies/d). This study is of great significance for assessing the distribution and sources of ARGs under the clean air initiative in China.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Humanos , Antibacterianos/farmacologia , RNA Ribossômico 16S/genética , Esgotos/análise , China , Poluição do Ar/análise , Material Particulado/análise , Resistência Microbiana a Medicamentos/genética , Estações do Ano , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos
8.
bioRxiv ; 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37425954

RESUMO

Background: Abnormal alpha-synuclein and iron accumulation in the brain play an important role in Parkinson's disease (PD). Herein, we aim at visualizing alpha-synuclein inclusions and iron deposition in the brains of M83 (A53T) mouse models of PD in vivo. Methods: Fluorescently labelled pyrimidoindole-derivative THK-565 was characterized by using recombinant fibrils and brains from 10-11 months old M83 mice, which subsequently underwent in vivo concurrent wide-field fluorescence and volumetric multispectral optoacoustic tomography (vMSOT) imaging. The in vivo results were verified against structural and susceptibility weighted imaging (SWI) magnetic resonance imaging (MRI) at 9.4 Tesla and scanning transmission X-ray microscopy (STXM) of perfused brains. Brain slice immunofluorescence and Prussian blue staining were further performed to validate the detection of alpha-synuclein inclusions and iron deposition in the brain, respectively. Results: THK-565 showed increased fluorescence upon binding to recombinant alpha-synuclein fibrils and alpha-synuclein inclusions in post-mortem brain slices from patients with Parkinson's disease and M83 mice. i.v. administration of THK-565 in M83 mice showed higher cerebral retention at 20 and 40 minutes post-injection by wide-field fluorescence compared to non-transgenic littermate mice, in congruence with the vMSOT findings. SWI/phase images and Prussian blue indicated the accumulation of iron deposits in the brains of M83 mice, presumably in the Fe3+ form, as evinced by the STXM results. Conclusion: We demonstrated in vivo mapping of alpha-synuclein by means of non-invasive epifluorescence and vMSOT imaging assisted with a targeted THK-565 label and SWI/STXM identification of iron deposits in M83 mouse brains ex vivo.

9.
Cells ; 12(13)2023 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-37443734

RESUMO

Neural tube defects (NTDs), including anencephaly and spina bifida, are common major malformations of fetal development resulting from incomplete closure of the neural tube. These conditions lead to either universal death (anencephaly) or severe lifelong complications (spina bifida). Despite hundreds of genetic mouse models of neural tube defect phenotypes, the genetics of human NTDs are poorly understood. Furthermore, pharmaceuticals, such as antiseizure medications, have been found clinically to increase the risk of NTDs when administered during pregnancy. Therefore, a model that recapitulates human neurodevelopment would be of immense benefit to understand the genetics underlying NTDs and identify teratogenic mechanisms. Using our self-organizing single rosette cortical organoid (SOSR-COs) system, we have developed a high-throughput image analysis pipeline for evaluating the SOSR-CO structure for NTD-like phenotypes. Similar to small molecule inhibition of apical constriction, the antiseizure medication valproic acid (VPA), a known cause of NTDs, increases the apical lumen size and apical cell surface area in a dose-responsive manner. GSK3ß and HDAC inhibitors caused similar lumen expansion; however, RNA sequencing suggests VPA does not inhibit GSK3ß at these concentrations. The knockout of SHROOM3, a well-known NTD-related gene, also caused expansion of the lumen, as well as reduced f-actin polarization. The increased lumen sizes were caused by reduced cell apical constriction, suggesting that impingement of this process is a shared mechanism for VPA treatment and SHROOM3-KO, two well-known causes of NTDs. Our system allows the rapid identification of NTD-like phenotypes for both compounds and genetic variants and should prove useful for understanding specific NTD mechanisms and predicting drug teratogenicity.


Assuntos
Anencefalia , Defeitos do Tubo Neural , Disrafismo Espinal , Gravidez , Feminino , Humanos , Camundongos , Animais , Ácido Valproico/farmacologia , Anencefalia/complicações , Anencefalia/genética , Glicogênio Sintase Quinase 3 beta/genética , Camundongos Knockout , Defeitos do Tubo Neural/induzido quimicamente , Defeitos do Tubo Neural/genética , Disrafismo Espinal/genética , Encéfalo/patologia , Proteínas dos Microfilamentos
11.
Small ; 19(37): e2206232, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37170734

RESUMO

Oligomerization of antimicrobial peptides (AMPs) is critical in their effects on pathogens. LL-37 and its truncated fragments are widely investigated regarding their structures, antimicrobial activities, and application, such as developing new antibiotics. Due to the small size and weak intermolecular interactions of LL-37 fragments, it is still elusive to establish the relationship between oligomeric states and antimicrobial activities. Here, an α-hemolysin nanopore, mass spectrometry (MS), and molecular dynamic (MD) simulations are used to characterize the oligomeric states of two LL-37 fragments. Nanopore studies provide evidence of trapping events related to the oligomer formation and provide further details on their stabilities, which are confirmed by MS and MD simulations. Furthermore, simulation results reveal the molecular basis of oligomer dynamics and states of LL-37 fragments. This work provides unique insights into the relationship between the oligomer dynamics of AMPs and their antimicrobial activities at the single-molecule level. The study demonstrates how integrating methods allows deciphering single molecule level understanding from nanopore sensing approaches.


Assuntos
Anti-Infecciosos , Nanoporos , Proteínas Hemolisinas/química , Simulação de Dinâmica Molecular
12.
bioRxiv ; 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37090564

RESUMO

Neural tube defects (NTDs) including anencephaly and spina bifida are common major malformations of fetal development resulting from incomplete closure of the neural tube. These conditions lead to either universal death (anencephaly) or life-long severe complications (spina bifida). Despite hundreds of genetic mouse models having neural tube defect phenotypes, the genetics of human NTDs are poorly understood. Furthermore, pharmaceuticals such as antiseizure medications have been found clinically to increase the risk of NTDs when administered during pregnancy. Therefore, a model that recapitulates human neurodevelopment would be of immense benefit to understand the genetics underlying NTDs and identify teratogenic mechanisms. Using our self-organizing single rosette spheroid (SOSRS) brain organoid system, we have developed a high-throughput image analysis pipeline for evaluating SOSRS structure for NTD-like phenotypes. Similar to small molecule inhibition of apical constriction, the antiseizure medication valproic acid (VPA), a known cause of NTDs, increases the apical lumen size and apical cell surface area in a dose-responsive manner. This expansion was mimicked by GSK3ß and HDAC inhibitors; however, RNA sequencing suggests VPA does not inhibit GSK3ß at these concentrations. Knockout of SHROOM3, a well-known NTD-related gene, also caused expansion of the lumen as well as reduced f-actin polarization. The increased lumen sizes were caused by reduced cell apical constriction suggesting that impingement of this process is a shared mechanism for VPA treatment and SHROOM3-KO, two well-known causes of NTDs. Our system allows the rapid identification of NTD-like phenotypes for both compounds and genetic variants and should prove useful for understanding specific NTD mechanisms and predicting drug teratogenicity.

13.
Angew Chem Int Ed Engl ; 62(23): e202216480, 2023 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-36880481

RESUMO

Prevalent in nature, protein oligomers play critical roles both physiologically and pathologically. The multimeric nature and conformational transiency of protein oligomers greatly complicate a more detailed glimpse into the molecular structure as well as function. In this minireview, the oligomers are classified and described on the basis of biological function, toxicity, and application. We also define the bottlenecks in recent oligomer studies and further review numerous frontier methods for engineering protein oligomers. Progress is being made on many fronts for a wide variety of applications, and protein grafting is highlighted as a promising and robust method for oligomer engineering. These advances collectively allow the engineering and design of stabilized oligomers that bring us one step closer to understanding their biological functions, toxicity, and a wide range of applications.


Assuntos
Peptídeos beta-Amiloides , Amiloide , Peptídeos beta-Amiloides/metabolismo , Amiloide/química , Engenharia de Proteínas , Conformação Molecular , Estrutura Molecular
14.
Comput Struct Biotechnol J ; 21: 1189-1204, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36817952

RESUMO

Three common Apolipoprotein E isoforms, ApoE2, ApoE3, and ApoE4, are key regulators of lipid homeostasis, among other functions. Apolipoprotein E can interact with amyloid proteins. The isoforms differ by one or two residues at positions 112 and 158, and possess distinct structural conformations and functions, leading to isoform-specific roles in amyloid-based neurodegenerative diseases. Over 30 different amyloid proteins have been found to share similar characteristics of structure and toxicity, suggesting a common interactome. The molecular and genetic interactions of ApoE with amyloid proteins have been extensively studied in neurodegenerative diseases, but have not yet been well connected and clarified. Here we summarize essential features of the interactions between ApoE and different amyloid proteins, identify gaps in the understanding of the interactome and propose the general interaction mechanism between ApoE isoforms and amyloid proteins. Perhaps more importantly, this review outlines what we can learn from the interactome of ApoE and amyloid proteins; that is the need to see both ApoE and amyloid proteins as a basis to understand neurodegenerative diseases.

15.
Sci Total Environ ; 871: 162035, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36754321

RESUMO

Aerosols are an important route for the transmission of antibiotic resistance genes (ARGs). Since the 2019 (COVID-19) pandemic, the large-scale use of disinfectants has effectively prevented the spread of environmental microorganisms, but studies regarding the antibiotic resistance of airborne bacteria remain limited. This study focused on four functional urban areas (commercial areas, educational areas, residential areas and wastewater treatment plant) to study the variations in ARG abundances, bacterial community structures and risks to human health during the COVID-19 pandemic in aerosol. The results indicated the abundance of ARGs during the COVID-19 period were up to approximately 13-fold greater than before the COVID-19 period. Large-scale disinfection resulted in a decrease in total bacterial abundance. However, chlorine-resistant bacteria tended to be survived. Among the four functional areas, the diversity and abundance of aerosol bacteria were highest in commercial aera. Antibiotic susceptibility assays suggested elevated resistance of isolated bacteria to several tested antibiotics due to disinfection exposure. The potential exposure risks of ARGs to human health were 2 times higher than before the COVID-19 pandemic, and respiratory intake was the main exposure route. The results highlighted the elevated antibiotic resistance of bacteria in aerosols that were exposed to disinfectants after the COVID-19 pandemic. This study provides theoretical guidance for the rational use of disinfectants and control of antimicrobial resistance.


Assuntos
COVID-19 , Desinfetantes , Humanos , Pandemias , Genes Bacterianos , Aerossóis e Gotículas Respiratórios , Resistência Microbiana a Medicamentos/genética , Bactérias/genética , Antibacterianos/farmacologia , Desinfetantes/farmacologia
16.
bioRxiv ; 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38168415

RESUMO

Focal cortical dysplasia (FCD) is a common cause of focal epilepsy that typically results from brain mosaic mutations in the mTOR cell signaling pathway. To identify new FCD genes, we developed an in vitro CRISPRi screen in human neurons and used FACS enrichment based on the FCD biomarker, phosphorylated S6 ribosomal protein (pS6). Using whole-genome (110,000 gRNAs) and candidate (129 gRNAs) libraries, we discovered 12 new genes that significantly increase pS6 levels. Interestingly, positive hits were enriched for brain-specific genes, highlighting the effectiveness of using human iPSC-derived induced neurons (iNeurons) in our screen. We investigated the signaling pathways of six candidate genes: LRRC4, EIF3A, TSN, HIP1, PIK3R3, and URI1. All six genes increased phosphorylation of S6. However, only two genes, PIK3R3 and HIP1, caused hyperphosphorylation more proximally in the AKT/mTOR/S6 signaling pathway. Importantly, these two genes have recently been found independently to be mutated in resected brain tissue from FCD patients, supporting the predictive validity of our screen. Knocking down each of the other four genes (LRRC4, EIF3A, TSN, and URI1) in iNeurons caused them to become resistant to the loss of growth factor signaling; without growth factor stimulation, pS6 levels were comparable to growth factor stimulated controls. Our data markedly expand the set of genes that are likely to regulate mTOR pathway signaling in neurons and provide additional targets for identifying somatic gene variants that cause FCD.

17.
J Inorg Biochem ; 236: 111945, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35952593

RESUMO

α-synuclein protein aggregates are the major constituent of Lewy bodies, which is a main pathogenic hallmark of Parkinson's disease. Both lipid membranes and Cu2+ ions can bind to α-synuclein and modulate its aggregation propensity and toxicity. However, the synergistic effect of copper ions and lipid membranes on α-synuclein remains to be explored. Here, we investigate how Cu2+ and α-synuclein simultaneously influence the lipidic structure of lipidic cubic phase(LCP) matrix by using small-angle X-ray scattering. α-Syn proteins destabilize the cubic-Pn3m phase of LCP that can be further recovered after the addition of Cu2 ions even at a low stoichiometric ratio. By using circular dichroism and nuclear magnetic resonance, we also study how lipid membranes and Cu2+ ions impact the secondary structures of α-synuclein at an atomic level. Although the secondary structure of α-synuclein with lipid membranes is not significantly changed to a large extent in the presence of Cu2+ ions, lipid membranes promote the interaction between α-synuclein C-terminus and Cu2+ ions. The modulation of Cu2+ ions and lipid membranes on α-synuclein dynamics and structure may play an important role in the molecular pathogenesis of Parkinson's disease.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Cobre/química , Humanos , Íons , Lipídeos , Doença de Parkinson/metabolismo , Agregados Proteicos , alfa-Sinucleína/metabolismo
18.
Front Pharmacol ; 13: 910629, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35873554

RESUMO

This study aimed to build a nasal semi-physiologically based pharmacokinetic (PBPK) model to predict the intranasal pharmacokinetic (PK) of the OC-01(varenicline) nasal spray and accelerate the development of this drug. Based on the physiology of the human upper respiratory system, the semi-PBPK model was established and validated using systemic plasma PK data of varenicline previously observed in Americans and Chinese. Drug concentrations, both in respiratory tissue and plasma circulation system, were well simulated, and it was indicated that local concentration at the target site (nasal cavity) was significantly higher than that of plasma when OC-01 nasal spray was administered. The nasal semi-PBPK model successfully depicted the absorption and distribution of intranasal varenicline in the respiratory tissues and provided an alternative to clinical PK study of OC-01 nasal spray in Chinese. Meanwhile the current study presented a viable framework for predicting respiratory concentrations for other novel nasal spray drugs by semi-PBPK modeling.

19.
Molecules ; 27(10)2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35630637

RESUMO

The tight binding of Cu and Zn ions to superoxide dismutase 1 (SOD1) maintains the protein stability, associated with amyotrophic lateral sclerosis (ALS). Yet, the quantitative studies remain to be explored for the metal-binding affinity of wild-type SOD1 and its mutants. We have investigated the demetallation of Cu,Zn-SOD1 and its ALS-related G93A mutant in the presence of different standard metal ion chelators at varying temperatures by using an LC-ICP MS-based approach and fast size-exclusion chromatography. Our results showed that from the slow first-order kinetics both metal ions Zn2+ and Cu2+ were released simultaneously from the protein at elevated temperatures. The rate of the release depends on the concentration of chelating ligands but is almost independent of their metal-binding affinities. Similar studies with the G93A mutant of Cu,Zn-SOD1 revealed slightly faster metal-release. The demetallation of Cu,Zn-SOD1 comes always to completion, which hindered the calculation of the KD values. From the Arrhenius plots of the demetallation in the absence of chelators ΔH‡ = 173 kJ/mol for wt and 191 kJ/mol for G93A mutant Cu,Zn-SOD1 was estimated. Obtained high ΔH values are indicative of the occurrence of protein conformational changes before demetallation and we concluded that Cu,Zn-SOD1 complex is in native conditions kinetically inert. The fibrillization of both forms of SOD1 was similar.


Assuntos
Esclerose Lateral Amiotrófica , Esclerose Lateral Amiotrófica/genética , Quelantes , Cobre/química , Humanos , Íons , Superóxido Dismutase/metabolismo , Superóxido Dismutase-1/genética , Zinco/metabolismo
20.
Chem Commun (Camb) ; 58(33): 5132-5135, 2022 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-35380562

RESUMO

Misfolding of the human protein α-synuclein results in toxic fibrils and the aggregation of Lewy bodies, which are a hallmark of Parkinson's disease in brain tissue. Here we disclose a supramolecular approach where peptidomimetics are rationally designed and pre-organised to recognize the surface of native helical α-Syn by forming complementary contacts with key patches of protein surface composed of charged and hydrophobic residues. Under lipid-catalyzed conditions the mimetics slow the rate of aggregation (thioflavin-T assay) and disrupt the misfolding pathway (electron microscopy of aggregates). This hypothesis is supported by comparison with a series of negative control compounds and with circular dichroism spectroscopy. Given the approach relies on selective recognition of both amino acid sequence and conformation (helical secondary structure) there is potential to develop these compounds as tools to unravel the currently intractable structure-function relationships of (i) missense mutation, and (ii) amyloid polymorphism with disease pathogenesis.


Assuntos
Doença de Parkinson , Peptidomiméticos , Amiloide/química , Humanos , Corpos de Lewy/química , Corpos de Lewy/metabolismo , Corpos de Lewy/patologia , Doença de Parkinson/metabolismo , Peptidomiméticos/metabolismo , alfa-Sinucleína/química
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