RESUMO
Thiamine (vitamin B1) functions as an essential coenzyme in cells. Humans and other mammals cannot synthesise this vitamin de novo and thus have to take it up from their diet. Eventually, every cell needs to import thiamine across its plasma membrane, which is mainly mediated by the two specific thiamine transporters SLC19A2 and SLC19A3. Loss of function mutations in either of these transporters lead to detrimental, life-threatening metabolic disorders. SLC19A3 is furthermore a major site of drug interactions. Many medications, including antidepressants, antibiotics and chemotherapeutics are known to inhibit this transporter, with potentially fatal consequences for patients. Despite a thorough functional characterisation over the past two decades, the structural basis of its transport mechanism and drug interactions has remained elusive. Here, we report seven cryo-electron microscopy (cryo-EM) structures of the human thiamine transporter SLC19A3 in complex with various ligands. Conformation-specific nanobodies enable us to capture different states of SLC19A3's transport cycle, revealing the molecular details of thiamine recognition and transport. We identify seven previously unknown drug interactions of SLC19A3 and present structures of the transporter in complex with the inhibitors fedratinib, amprolium and hydroxychloroquine. These data allow us to develop an understanding of the transport mechanism and ligand recognition of SLC19A3.
Assuntos
Microscopia Crioeletrônica , Proteínas de Membrana Transportadoras , Tiamina , Tiamina/metabolismo , Tiamina/química , Humanos , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/genética , Transporte Biológico , Modelos Moleculares , Ligantes , Células HEK293 , Interações MedicamentosasRESUMO
As the first identified multidrug efflux pump in Mycobacterium tuberculosis (Mtb), EfpA is an essential protein and promising drug target. However, the functional and inhibitory mechanisms of EfpA are poorly understood. Here we report cryo-EM structures of EfpA in outward-open conformation, either bound to three endogenous lipids or the inhibitor BRD-8000.3. Three lipids inside EfpA span from the inner leaflet to the outer leaflet of the membrane. BRD-8000.3 occupies one lipid site at the level of inner membrane leaflet, competitively inhibiting lipid binding. EfpA resembles the related lysophospholipid transporter MFSD2A in both overall structure and lipid binding sites and may function as a lipid flippase. Combining AlphaFold-predicted EfpA structure, which is inward-open, we propose a complete conformational transition cycle for EfpA. Together, our results provide a structural and mechanistic foundation to comprehend EfpA function and develop EfpA-targeting anti-TB drugs.
Assuntos
Proteínas de Bactérias , Mycobacterium tuberculosis , Antituberculosos/farmacologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Sítios de Ligação , Transporte Biológico , Microscopia Crioeletrônica , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Membrana Transportadoras/química , Modelos Moleculares , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/efeitos dos fármacos , Conformação ProteicaRESUMO
Cellular homeostasis depends on the supply of metabolic energy in the form of ATP and electrochemical ion gradients. The construction of synthetic cells requires a constant supply of energy to drive membrane transport and metabolism. Here, we provide synthetic cells with long-lasting metabolic energy in the form of an electrochemical proton gradient. Leveraging the L-malate decarboxylation pathway we generate a stable proton gradient and electrical potential in lipid vesicles by electrogenic L-malate/L-lactate exchange coupled to L-malate decarboxylation. By co-reconstitution with the transporters GltP and LacY, the synthetic cells maintain accumulation of L-glutamate and lactose over periods of hours, mimicking nutrient feeding in living cells. We couple the accumulation of lactose to a metabolic network for the generation of intermediates of the glycolytic and pentose phosphate pathways. This study underscores the potential of harnessing a proton motive force via a simple metabolic network, paving the way for the development of more complex synthetic systems.
Assuntos
Malatos , Descarboxilação , Malatos/metabolismo , Ácido Glutâmico/metabolismo , Transporte Biológico , Células Artificiais/metabolismo , Ácido Láctico/metabolismo , Lactose/metabolismo , Escherichia coli/metabolismo , Nutrientes/metabolismo , Força Próton-Motriz , Antiporters/metabolismo , Glicólise , Redes e Vias Metabólicas , Prótons , Via de Pentose FosfatoRESUMO
Glucose is the primary source of energy for many organisms and is efficiently taken up by bacteria through a dedicated transport system that exhibits high specificity. In Escherichia coli, the glucose-specific transporter IICBGlc serves as the major glucose transporter and functions as a component of the phosphoenolpyruvate-dependent phosphotransferase system. Here, we report cryo-electron microscopy (cryo-EM) structures of the glucose-bound IICBGlc protein. The dimeric transporter embedded in lipid nanodiscs was captured in the occluded, inward- and occluded, outward-facing conformations. Together with biochemical and biophysical analyses, and molecular dynamics (MD) simulations, we provide insights into the molecular basis and dynamics for substrate recognition and binding, including the gates regulating the binding sites and their accessibility. By combination of these findings, we present a mechanism for glucose transport across the plasma membrane. Overall, this work provides molecular insights into the structure, dynamics, and mechanism of the IICBGlc transporter in a native-like lipid environment.
Assuntos
Microscopia Crioeletrônica , Proteínas de Escherichia coli , Escherichia coli , Glucose , Simulação de Dinâmica Molecular , Escherichia coli/metabolismo , Escherichia coli/genética , Glucose/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/ultraestrutura , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/metabolismo , Sistema Fosfotransferase de Açúcar do Fosfoenolpiruvato/química , Sítios de Ligação , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Proteínas Facilitadoras de Transporte de Glucose/química , Proteínas Facilitadoras de Transporte de Glucose/genética , Conformação Proteica , Transporte Biológico , Ligação ProteicaRESUMO
This study used Caco-2 cells and normal rats to investigate the in vitro absorption characteristics and in vivo pharmacokinetic characteristics of cannabidiol(CBD) and explore the anti-inflammatory mechanism of CBD. The safe concentration range of CBD was determined by the CCK-8 assay, and then the effects of time, concentration, temperature, endocytosis inhibitors, and transport inhibitors on the transepithelial absorption and transport of CBD were assessed. The blood drug concentration was measured at different time points after oral administration in rats for pharmacokinetic profiling, and the pharmacokinetic parameters were calculated. The Caco-2 cell model of inflammation injury was established with lipopolysaccharide(LPS). The effects of CBD on lactate dehydrogenase(LDH) activity, transendothelial electrical resistance(TEER), and levels of inflammatory cytokines of the modeled cells were exami-ned, on the basis of which the anti-inflammatory mechanism of CBD was deciphered. The results showed that within the concentration range tested in this study, the CBD uptake by Caco-2 cells reached saturation at the time point of 2 h. Moreover, the CBD uptake was positively correlated with concentration and temperature and CBD could be endocytosed into the cells. CBD could penetrate Caco-2 cells through active transport pathways involving multidrug resistance-associate protein 2(MRP2) and breast cancer resistance protein(BCRP), while the addition of P-gp inhibitors had no effect on CBD transport. Rats exhibited rapid absorption of CBD, with the peak time(t_(max)) of(1.00±0.11) h, and fast elimination of CBD, with a half-life(t_(1/2)) of only(1.86±0.16) h. In addition, CBD significantly ameliorated the increased LDH activity and decreased TEER that were caused by inflammatory response. It maintained the intestinal barrier by down-regulating the expression of pro-inflammatory cytokines interleukin-8(IL-8), interleukin-1 beta(IL-1ß) and tumor necrosis factor-α(TNF-α), thus exerting anti-inflammatory effects.
Assuntos
Anti-Inflamatórios , Canabidiol , Canabidiol/farmacologia , Células CACO-2 , Humanos , Animais , Anti-Inflamatórios/farmacologia , Ratos , Masculino , Transporte Biológico/efeitos dos fármacos , Ratos Sprague-DawleyRESUMO
KEY MESSAGE: Boron is essential for plants, but excess can induce toxicity. Boron (B) is a vital micronutrient for plants, but excess B can induce toxicity symptoms and reduce crop yields. B bioavailability depends on soil properties, including clay type, pH, and organic matter content. Symptoms of B toxicity include reduced shoot and root growth, leaf chlorosis and necrosis, impaired photosynthesis, and disrupted pollen development. This review paper examines the current knowledge on B toxicity mechanisms, tolerance strategies, and management approaches in plants. This review covers (1) factors affecting B bioavailability; (2) toxicity symptoms in plants; (3) uptake, transport, and detoxification mechanisms; and (4) strategies. To mitigate toxicity, plants reduce B uptake, activate efflux transporters, compartmentalize B, and enhance antioxidant systems. On the basis of this review, future research should focus on identifying novel tolerance mechanisms, exploring genetic strategies for improved B management, and developing innovative agronomic interventions. These insights will facilitate the breeding and management of crops for enhanced productivity under B toxicity stress.
Assuntos
Boro , Boro/toxicidade , Boro/metabolismo , Plantas/efeitos dos fármacos , Plantas/metabolismo , Produtos Agrícolas/efeitos dos fármacos , Estresse Fisiológico , Solo/química , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Transporte Biológico , Capacidades de EnfrentamentoRESUMO
Polyamines, characterized by their polycationic nature, are ubiquitously present in all organisms and play numerous cellular functions. Among polyamines, spermidine stands out as the predominant type in both prokaryotic and eukaryotic cells. The PotD-PotABC protein complex in Escherichia coli, belonging to the adenosine triphosphate-binding cassette transporter family, is a spermidine-preferential uptake system. Here, we report structural details of the polyamine uptake system PotD-PotABC in various states. Our analyses reveal distinct "inward-facing" and "outward-facing" conformations of the PotD-PotABC transporter, as well as conformational changes in the "gating" residues (F222, Y223, D226, and K241 in PotB; Y219 and K223 in PotC) controlling spermidine uptake. Therefore, our structural analysis provides insights into how the PotD-PotABC importer recognizes the substrate-binding protein PotD and elucidates molecular insights into the spermidine uptake mechanism of bacteria.
Assuntos
Transportadores de Cassetes de Ligação de ATP , Proteínas de Escherichia coli , Escherichia coli , Espermidina , Espermidina/metabolismo , Espermidina/química , Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/química , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Escherichia coli/metabolismo , Escherichia coli/genética , Transporte Biológico , Modelos Moleculares , Conformação Proteica , Ligação ProteicaRESUMO
The bHLH (basic helix-loop-helix) transcription factor AtCFLAP2 regulates epidermal wax accumulation, but the underlying molecular mechanism remains unknown. We obtained BnUC1mut (BnaA05g18250D homologous to AtCFLAP2) from a Brassica napus mutant with up-curling leaves (Bnuc1) and epidermal wax deficiency via map-based cloning. BnUC1mut contains a point mutation (N200S) in the conserved dimerization domain. Overexpressing BnUC1mut in ZS11 (Zhongshuang11) significantly decreased the leaf epidermal wax content, resulting in up-curled and glossy leaves. In contrast, knocking out BnUC1mut in ZS11-NIL (Zhongshuang11-near-isogenic line) restored the normal leaf phenotype (i.e., flat) and significantly increased the leaf epidermal wax content. The point mutation weakens the ability of BnUC1mut to bind to the promoters of VLCFA (very-long-chain fatty acids) synthesis-related genes, including KCS (ß-ketoacyl coenzyme synthase) and LACS (long-chain acyl CoA synthetase), as well as lipid transport-related genes, including LTP (non-specific lipid transfer protein). The resulting sharp decrease in the transcription of genes affecting VLCFA biosynthesis and lipid transport disrupts the normal accumulation of leaf epidermal wax. Thus, BnUC1 influences epidermal wax formation by regulating the expression of LTP and genes associated with VLCFA biosynthesis. Our findings provide a foundation for future investigations on the mechanism mediating plant epidermal wax accumulation.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Brassica napus , Proteínas de Plantas , Ceras , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Transporte Biológico , Brassica napus/metabolismo , Brassica napus/genética , Regulação da Expressão Gênica de Plantas , Metabolismo dos Lipídeos/genética , Epiderme Vegetal/metabolismo , Epiderme Vegetal/genética , Folhas de Planta/metabolismo , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Ceras/metabolismoRESUMO
Mycobacterial membrane protein Large 3 (MmpL3) of Mycobacterium tuberculosis (Mtb) is crucial for the translocation of trehalose monomycolate (TMM) across the inner bacterial cell membrane, making it a promising target for anti-tuberculosis (TB) drug development. While several structural, microbiological, and in vitro studies have provided significant insights, the precise mechanisms underlying TMM transport by MmpL3 and its inhibition remain incompletely understood at the atomic level. In this study, molecular dynamic (MD) simulations for the apo form and seven inhibitor-bound forms of Mtb MmpL3 were carried out to obtain a thorough comprehension of the protein's dynamics and function. MD simulations revealed that the seven inhibitors in this work stably bind to the central channel of the transmembrane domain and primarily forming hydrogen bonds with ASP251, ASP640, or both residues. Through dynamical cross-correlation matrix and principal component analysis analyses, several types of coupled motions between different domains were observed in the apo state, and distinct conformational states were identified using Markov state model analysis. These coupled motions and varied conformational states likely contribute to the transport of TMM. However, simulations of inhibitor-bound MmpL3 showed an enlargement of the proton channel, potentially disrupting coupled motions. This indicates that inhibitors may impair MmpL3's transport function by directly blocking the proton channel, thereby hindering coordinated domain movements and indirectly affecting TMM translocation.
Assuntos
Proteínas de Bactérias , Simulação de Dinâmica Molecular , Mycobacterium tuberculosis , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/química , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Trealose/química , Trealose/metabolismo , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Transporte Biológico , Ligação Proteica , Fatores CordaRESUMO
The gut communicates with the brain in a variety of ways known as the gut-brain axis (GBA), which is known to affect neurophysiological functions as well as neuronal disorders. Exosomes capable of passing through the blood-brain-barrier (BBB) have received attention as a mediator of gut-brain signaling and drug delivery vehicles. In conventional well plate-based experiments, it is difficult to observe the exosome movement in real time. Here, we developed a microfluidic-based GBA chip for co-culturing gut epithelial cells and neuronal cells and simultaneously observing exosome transport. The GBA-chip is aimed to mimic the in vivo situation of convective flow in blood vessels and convective and diffusive transport in the tissue interstitium. Here, fluorescence-labeled exosome was produced by transfection of HEK-293T cells with CD63-GFP plasmid. We observed in real time the secretion of CD63-GFP-exosomes by the transfected HEK-293T cells in the chip, and transport of the exosomes to neuronal cells and analyzed the dynamics of GFP-exosome movement. Our model is expected to enhance understanding of the roles of exosome in GBA.
Assuntos
Encéfalo , Exossomos , Dispositivos Lab-On-A-Chip , Humanos , Exossomos/metabolismo , Células HEK293 , Encéfalo/metabolismo , Encéfalo/citologia , Técnicas de Cocultura/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Neurônios/metabolismo , Neurônios/citologia , Transporte Biológico , Barreira Hematoencefálica/metabolismo , Modelos BiológicosRESUMO
PURPOSE: To improve the oral bioavailability of albendazole (ABZ), a series of albendazole-bile acid conjugates (ABCs) were synthesized. ABC's transmembrane transport mechanism and in vivo pharmacokinetic properties were preliminarily studied. METHODS: The transmembrane transport mechanism of ABCs was studied using the Caco-2 monolayer cell model and intestinal perfusion model. The concentration of ABCs and ABZ were evaluated using High-Performance Liquid Chromatography (HPLC) and HPLC-Mass Spectrometry (HPLC-MS/MS). RESULTS: Compared to ABZ, better permeability was observed for different types and concentrations of ABCs using the Caco-2 monolayer cell model, with ABC-C8 showing the highest permeability. The transmembrane transport of ABCs was affected by ASBT inhibitors, indicating an ASBT-mediated active transport mechanism. Additionally, introducing cholic acid resulted in ABZ no longer being a substrate for P-gp, MRP2, and BCRP, effectively reversing ABZ efflux. In vivo unidirectional intestinal perfusion results in rats showed that ABCs altered the absorption site of ABZ from the jejunum to the ileum. The absorption efficiency of ABCs in each intestinal segment was higher than that of ABZ, and the transmembrane transport efficiency decreased with increasing concentrations of ASBT inhibitors. This further confirmed the presence of both passive diffusion and ASBT-mediated active transport mechanisms in the transport of ABCs. The solubility of ABCs in gastric juice and pharmacokinetics in rats showed that ABZ-C4 exhibited enhanced solubility. Moreover, ABCs significantly increased oral bioavailability compared to ABZ, with ABC-C4 showing an approximately 31-fold increase in bioavailability. CONCLUSION: The transmembrane transport mechanism of ABCs involves a combination of ASBT-mediated active transport and passive diffusion. Moreover, the incorporation of BAs successfully reverses the efflux of ABZ by efflux proteins. Among the synthesized conjugates, ABC-C4 demonstrated superior dissolution behavior both in vitro and in vivo.
Assuntos
Albendazol , Ácidos e Sais Biliares , Absorção Intestinal , Ratos Sprague-Dawley , Células CACO-2 , Animais , Albendazol/farmacocinética , Albendazol/química , Albendazol/farmacologia , Albendazol/administração & dosagem , Humanos , Masculino , Absorção Intestinal/efeitos dos fármacos , Ratos , Ácidos e Sais Biliares/metabolismo , Ácidos e Sais Biliares/química , Disponibilidade Biológica , Transporte Biológico , Administração OralRESUMO
Proper fetal development requires tight regulation of serotonin concentrations within the fetoplacental unit. This homeostasis is partly maintained by the placental transporter OCT3/SLC22A3, which takes up serotonin from the fetal circulation. Metformin, an antidiabetic drug commonly used to treat gestational diabetes mellitus, was shown to inhibit OCT3. We, therefore, hypothesized that its use during pregnancy could disrupt placental serotonin homeostasis. This hypothesis was tested using three experimental model systems: primary trophoblast cells isolated from the human term placenta, fresh villous human term placenta fragments, and rat term placenta perfusions. Inhibition of serotonin transport by metformin at three concentrations (1⯵M, 10⯵M, and 100⯵M) was assessed in all three models. The OCT3 inhibitor decynium-22 (100⯵M) and paroxetine (100⯵M), a dual inhibitor of SERT and OCT3, were used as controls. In primary trophoblasts, paroxetine exhibited the strongest inhibition of serotonin uptake, followed by decynium-22. Metformin showed a concentration-dependent effect, reducing serotonin uptake by up to 57â¯% at the highest concentration. Its inhibitory effect was less pronounced in fresh villous fragments but remained statistically significant at all concentrations. In the perfused rat placenta, metformin demonstrated a concentration-dependent effect, reducing placental serotonin uptake by 44â¯% at the highest concentration tested. Our findings across all experimental models show inhibition of placental OCT3 by metformin, resulting in reduced serotonin uptake by the trophoblast. This sheds light on mechanisms that may underpin metformin-mediated effects on fetal development.
Assuntos
Metformina , Placenta , Serotonina , Trofoblastos , Metformina/farmacologia , Feminino , Gravidez , Animais , Serotonina/metabolismo , Placenta/metabolismo , Placenta/efeitos dos fármacos , Humanos , Trofoblastos/metabolismo , Trofoblastos/efeitos dos fármacos , Ratos , Transporte Biológico/efeitos dos fármacos , Fator 3 de Transcrição de Octâmero/metabolismo , Hipoglicemiantes/farmacologia , Células Cultivadas , Ratos Wistar , Proteínas de Transporte de Cátions OrgânicosRESUMO
Zinc (Zn) and nitrogen (N) are the two crucial nutrients for tea plant growth and development and contribute to the quality formation of tea fresh leaves. In this study, a zinc/iron-regulated transporter-like protein 4 gene (i.e., CsZIP4) was functionally characterized. Expression profiling showed that CsZIP4 could be induced by Zn stresses and a N deficiency. Heterologous expression of CsZIP4 in yeast revealed that CsZIP4 possessed the capacity for Zn transport but not ammonium. Moreover, CsZIP4 overexpression in Arabidopsis thaliana promoted Zn and N uptake and transport and contributed to alleviate Zn stresses by collaborating with N supply, which might be interrelated to the expression of N or Zn metabolism-related genes, such as AtNRT1.1 and AtZIP4. Additionally, CsZIP4 was localized in the plasma membrane and chloroplast, which was helpful in maintaining cellular homeostasis under a Zn excess. Furthermore, silencing of CsZIP4 in tea plants by virus-induced gene silencing increased the chlorophyll content but decreased the Zn content. Finally, the yeast one-hybrid assay demonstrated that CsbZIP2 bound to the CsZIP4 promoter. These results will shed light on the functions of CsZIP4 in the N and Zn interaction in tea plants.
Assuntos
Camellia sinensis , Regulação da Expressão Gênica de Plantas , Nitrogênio , Proteínas de Plantas , Zinco , Camellia sinensis/metabolismo , Camellia sinensis/genética , Camellia sinensis/química , Zinco/metabolismo , Nitrogênio/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Transporte Biológico , Ferro/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/química , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Transporte de Cátions/genéticaRESUMO
The epidermal growth factor receptor (EGFR) plays a pivotal role in tumor progression and is an essential therapeutic target for treating malignant gliomas. Small interfering RNA (siRNA) has the potential to selectively degrade EGFR mRNA, yet its clinical utilization is impeded by various challenges, such as inefficient targeting and limited escape from lysosomes. Our research introduces polyethylene glycol (PEG) and endoplasmic reticulum membrane-coated siEGFR nanoplexes (PEhCv/siEGFR NPs) as an innovative approach to brain glioma therapy by overcoming several obstacles: 1) Tumor-derived endoplasmic reticulum membrane modifications provide a homing effect, facilitating targeted accumulation and cellular uptake; 2) Endoplasmic reticulum membrane proteins mediate a non-degradable "endosome-Golgi-endoplasmic reticulum" transport pathway, circumventing lysosomal degradation. These nanoplexes demonstrated significantly enhanced siEGFR gene silencing in both in vitro and in vivo U87 glioma models. The findings of this study pave the way for the advanced design and effective application of nucleic acid-based therapeutic nanocarriers.
Assuntos
Neoplasias Encefálicas , Retículo Endoplasmático , Receptores ErbB , Glioma , RNA Interferente Pequeno , Glioma/patologia , Glioma/terapia , Glioma/tratamento farmacológico , Glioma/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/metabolismo , Humanos , Receptores ErbB/metabolismo , Linhagem Celular Tumoral , Animais , Retículo Endoplasmático/metabolismo , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/farmacologia , Camundongos Nus , Polietilenoglicóis/química , Nanopartículas/química , Inativação Gênica , Camundongos , Transporte Biológico , Biomimética/métodos , Camundongos Endogâmicos BALB CRESUMO
The productive replication of human immunodeficiency virus type 1 (HIV-1) involves intricate interactions between viral proteins and host cell machinery. However, the contributions of the lysosomal pathways for HIV-1 replication are not fully understood. The goal of this study was to determine the impact of lysosome-targeting compounds on HIV-1 replication and identify the cellular changes that are linked to HIV-1 inhibition using cell culture models of HIV-1 infection. Here, we demonstrate that the treatment of cells with various pharmacological agents known to inhibit lysosomal functions interfere with HIV-1 replication. The vacuolar ATPase (V-ATPase) inhibitor bafilomycin A1 exerted a potent inhibition of HIV-1 replication. Bafilomycin A1 inhibition of HIV-1 was independent of coreceptor tropism of HIV-1. Our data suggest that bafilomycin A1 inhibits HIV-1 at the post-integration steps of the virus life cycle, which include viral gene expression, virus assembly, and/or egress. Analysis of the cellular alterations following bafilomycin A1 treatment indicates that bafilomycin A1 causes a disruption in lysosome structure and functions. Treatment of cells with bafilomycin A1 caused an accumulation of unesterified cholesterol in lysosomes along with the expansion of the lysosomal compartments. Interestingly, the overexpression of the lysosomal cholesterol transporter Niemann-Pick type C 1 (NPC1) partially relieved bafilomycin A1 inhibition of HIV-1. Collectively, our data suggest that bafilomycin A1 inhibits HIV-1 replication in part by disrupting the lysosomal cholesterol trafficking pathway.
Assuntos
Colesterol , Infecções por HIV , HIV-1 , Lisossomos , Macrolídeos , Humanos , Transporte Biológico/efeitos dos fármacos , Linhagem Celular , Colesterol/metabolismo , Infecções por HIV/virologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/metabolismo , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Lisossomos/metabolismo , Lisossomos/efeitos dos fármacos , Macrolídeos/farmacologia , Replicação Viral/efeitos dos fármacosRESUMO
Recent studies have reported the benefits of food-derived peptides for memory dysfunction. Beyond the physiological effects of peptides, their bioavailability to the brain still remains unclear since the blood-brain barrier (BBB) strictly controls the transportation of compounds to the brain. Here, updated transportation studies on BBB transportable peptides are introduced and evaluated using in vitro BBB models, in situ perfusion, and in vivo mouse experiments. Additionally, the mechanisms of action of brain health peptides in relation to the pathogenesis of neurodegenerative diseases, particularly Alzheimer's disease, are discussed. This discussion follows a summary of bioactive peptides with neuroprotective effects that can improve cognitive decline through various mechanisms, including anti-inflammatory, antioxidative, anti-amyloid ß aggregation, and neurotransmitter regulation.
Assuntos
Doença de Alzheimer , Barreira Hematoencefálica , Encéfalo , Memória , Peptídeos , Animais , Barreira Hematoencefálica/metabolismo , Humanos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Memória/efeitos dos fármacos , Memória/fisiologia , Peptídeos/farmacologia , Doença de Alzheimer/metabolismo , Transporte Biológico , Fármacos Neuroprotetores/farmacologia , Camundongos , Transtornos da Memória/tratamento farmacológicoRESUMO
The biological behavior of flusulfinam, a potential commercial chiral herbicide for rice, has not been well explored. Herein, the uptake of chiral flusulfinam by rice and its transport, degradation, and subcellular distribution in rice (Oryza sativa L.) were investigated. The enantiomeric fraction (EF) in roots was 0.54 during 0 d to 7 d in hydroponic laboratory conditions. The bioconcentration factor of flusulfinam enantiomers was 2.1, suggesting an absence of observed enantioselectivity in the absorption process. Notably, the EF in the shoots decreased to 0.35 on the 7th day. The translocation factors of R- and S-flusulfinam were 0.12 and 0.27, respectively, indicating a preferential transfer of the S-flusulfinam from the root to the shoot. Flusulfinam was identified in the root after spraying. The translocation factors of R- and S-flusulfinam were consistently similar, signifying the capacity for downward movement without enantioselectivity. Interestingly, the degradation half-lives of R- and S-flusulfinam in the total plant were 5.50 and 5.06 d (p < 0.05), respectively, supporting the preferential degradation of S-flusulfinam throughout the total plant. Flusulfinam primarily entered the roots via the apoplastic pathway and was subsequently transported within the plant through aquaporins and ion channels. The subcellular distribution experiment revealed the predominant accumulation of flusulfinam enantiomers in soluble components (84%) with no enantioselectivity in these processes. There was upregulation lipid transfer protein-2 and carboxylesterases15 genes, which could explain the preferential transport and degradation of S-flusulfinam. This study is important in assessing the environmental risk associated with flusulfinam and ensuring food safety.
Assuntos
Herbicidas , Oryza , Oryza/metabolismo , Herbicidas/metabolismo , Estereoisomerismo , Transporte Biológico , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismoRESUMO
The synthetic auxin 2,4-D and the 4-hydroxyphenylpyruvate dioxygenase inhibitor pyrasulfotole are phloem-mobile post-emergence herbicides, the latter applied in co-formulation with either bromoxynil (a contact herbicide causing leaf desiccation) or MCPA (another synthetic auxin). Previous studies have shown a wide range of 2,4-D translocation phenotypes in resistant populations of the agricultural weed Raphanus raphanistrum, but it was hypothesised that enhanced movement out of the apical meristem could contribute to resistance. Little is known about pyrasulfotole translocation or the effect of bromoxynil on pyrasulfotole movement. Therefore, the behaviour of pyrasulfotole and 2,4-D applied to the growing point of susceptible and resistant R. raphanistrum seedlings was assessed, along with the effect of bromoxynil on pyrasulfotole translocation. The small amount of herbicide directly contacting the growing point after spraying was sufficient to induce herbicide symptoms, and there was no enhancement of translocation away from the growing point in either pyrasulfotole- or 2,4-D-resistant populations. Bromoxynil had a slightly inhibitory effect on pyrasulfotole translocation in some populations, somewhat negating the minor differences observed among populations when pyrasulfotole was applied alone. Resistance to pyrasulfotole could not explained by enhanced metabolism or vacuolar sequestration of the herbicide. Overall, differential translocation in either the treated leaves or apical meristems does not appear to be a major determinant of resistance to pyrasulfotole or 2,4-D.
Assuntos
Ácido 2,4-Diclorofenoxiacético , Resistência a Herbicidas , Herbicidas , Raphanus , Herbicidas/farmacologia , Ácido 2,4-Diclorofenoxiacético/farmacologia , Raphanus/efeitos dos fármacos , Raphanus/metabolismo , Plântula/efeitos dos fármacos , Plântula/metabolismo , Pironas/farmacologia , Transporte Biológico , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Isoxazóis , Nitrilas , SulfonasRESUMO
Deformability is one of the critical attributes of nanoparticle (NP) drug carriers, along with size, shape, and surface properties. It affects various aspects of NP biotransport, ranging from circulation and biodistribution to interactions with biological barriers and target cells. Recent studies report additional roles of NP deformability in biotransport processes, including protein corona formation, intracellular trafficking, and organelle distribution. This review focuses on the literature published in the past five years to update our understanding of NP deformability and its effect on NP biotransport. We introduce different methods of modulating and evaluating NP deformability and showcase recent studies that compare a series of NPs in their performance in biotransport events at all levels, highlighting the consensus and disagreement of the findings. It concludes with a perspective on the intricacy of systematic investigation of NP deformability and future opportunities to advance its control toward optimal drug delivery.
Assuntos
Nanopartículas , Nanopartículas/química , Humanos , Animais , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Distribuição Tecidual , Transporte Biológico , Propriedades de SuperfícieRESUMO
Microplastics (MPs) are solid plastic particles less than or equal to 5 mm in size that are insoluble in water, and when the diameter is further reduced to <1 micrometer (µm), we call them nanoplastics (NPs). MPs and NPs are widely present in the atmosphere, and plastic particles have also been detected in the sputum of patients with respiratory diseases. This warns us that these tiny plastic particles are a potential threat to human respiratory health. The lungs, as the main organs of the respiratory system, are more likely to be adversely affected by inhaled NPs. However, the mechanism of transport and transformation of NPs in the lung is not clear, so our review mainly focuses on a series of effects and mechanisms of NPs on lung cells through absorption, distribution, metabolism, excretion (ADME) after inhalation into the human body. The most commonly used models in these experimental studies we focus on are A549 and BEAS-2B cells, which are used to model the lung cell response to plastic particles. In addition, we also summarize some shortcomings of these experiments and prospects for future studies, hoping to provide further clues for future studies and contribute to the prevention of related hazards and diseases.