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1.
Int J Mol Sci ; 25(6)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38542527

RESUMO

Angiopoietin-like protein 3 (ANGPTL3) is a plasmatic protein that plays a crucial role in lipoprotein metabolism by inhibiting the lipoprotein lipase (LPL) and the endothelial lipase (EL) responsible for the hydrolysis of phospholipids on high-density lipoprotein (HDL). Interest in developing new pharmacological therapies aimed at inhibiting ANGPTL3 has been growing due to the hypolipidemic and antiatherogenic profile observed in its absence. The goal of this study was the in silico characterization of the interaction between ANGPTL3 and EL. Because of the lack of any structural information on both the trimeric coiled-coil N-terminal domain of ANGPTL3 and the EL homodimer as well as data regarding their interactions, the first step was to obtain the three-dimensional model of these two proteins. The models were then refined via molecular dynamics (MD) simulations and used to investigate the interaction mechanism. The analysis of interactions in different docking poses and their refinement via MD allowed the identification of three specific glutamates of ANGPTL3 that recognize a positively charged patch on the surface of EL. These ANGPTL3 key residues, i.e., Glu154, Glu157, and Glu160, could form a putative molecular recognition site for EL. This study paves the way for future investigations aimed at confirming the recognition site and at designing novel inhibitors of ANGPTL3.


Assuntos
Proteína 3 Semelhante a Angiopoietina , Lipase , Proteínas Semelhantes a Angiopoietina , Lipase/metabolismo , Lipase Lipoproteica/metabolismo , Lipoproteínas HDL/metabolismo , Fosfolipídeos/metabolismo , Triglicerídeos , Angiopoietinas/metabolismo
2.
Proteins ; 91(5): 619-633, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36511838

RESUMO

Riboflavin is an essential water-soluble vitamin that needs to be provided through the diet because of the conversion into flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), important cofactors in hundreds of flavoenzymes. The adsorption and distribution of riboflavin is mediated by transmembrane transporters of the SLC52 family, namely RFVT1-3, whose mutations are mainly associated with two diseases, MADD and the Brown-Vialetto-Van Laere syndrome. Interest in RFVTs as pharmacological targets has increased in the last few years due to their overexpression in several cancer cells, which can be exploited both by blocking the uptake of riboflavin into the cancerous cells, and by performing cancer targeted delivery of drugs with a high affinity for RFVTs. In this work, we propose three-dimensional structural models for all three human riboflavin transporters obtained by state-of-the-art artificial intelligence-based methods, which were then further refined with molecular dynamics simulations. Furthermore, two of the most notable mutations concerning RFVT2 and RFVT3 (W31S and N21S, respectively) were investigated studying the interactions between the wild-type and mutated transporters with riboflavin.


Assuntos
Inteligência Artificial , Perda Auditiva Neurossensorial , Humanos , Riboflavina/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Perda Auditiva Neurossensorial/genética , Relação Estrutura-Atividade , Mononucleotídeo de Flavina , Flavina-Adenina Dinucleotídeo/metabolismo
3.
Genet Med ; 25(11): 100922, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37403762

RESUMO

PURPOSE: RPH3A encodes a protein involved in the stabilization of GluN2A subunit of N-methyl-D-aspartate (NMDA)-type glutamate receptors at the cell surface, forming a complex essential for synaptic plasticity and cognition. We investigated the effect of variants in RPH3A in patients with neurodevelopmental disorders. METHODS: By using trio-based exome sequencing, GeneMatcher, and screening of 100,000 Genomes Project data, we identified 6 heterozygous variants in RPH3A. In silico and in vitro models, including rat hippocampal neuronal cultures, have been used to characterize the effect of the variants. RESULTS: Four cases had a neurodevelopmental disorder with untreatable epileptic seizures [p.(Gln73His)dn; p.(Arg209Lys); p.(Thr450Ser)dn; p.(Gln508His)], and 2 cases [p.(Arg235Ser); p.(Asn618Ser)dn] showed high-functioning autism spectrum disorder. Using neuronal cultures, we demonstrated that p.(Thr450Ser) and p.(Asn618Ser) reduce the synaptic localization of GluN2A; p.(Thr450Ser) also increased the surface levels of GluN2A. Electrophysiological recordings showed increased GluN2A-dependent NMDA ionotropic glutamate receptor currents for both variants and alteration of postsynaptic calcium levels. Finally, expression of the Rph3AThr450Ser variant in neurons affected dendritic spine morphology. CONCLUSION: Overall, we provide evidence that missense gain-of-function variants in RPH3A increase GluN2A-containing NMDA ionotropic glutamate receptors at extrasynaptic sites, altering synaptic function and leading to a clinically variable neurodevelopmental presentation ranging from untreatable epilepsy to autism spectrum disorder.


Assuntos
Transtorno do Espectro Autista , Epilepsia , Animais , Humanos , Ratos , Transtorno do Espectro Autista/genética , Epilepsia/genética , Mutação de Sentido Incorreto/genética , N-Metilaspartato/metabolismo , Neurônios/metabolismo , Rabfilina-3A
4.
Glycoconj J ; 40(6): 655-668, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38100017

RESUMO

Since the 1980s, it has been known that the administration of ganglioside GM1 to cultured cells induced or enhanced neuronal differentiation. GM1 mechanism of action relies on its direct interaction and subsequent activation of the membrane tyrosine kinase receptor, TrkA, which naturally serves as NGF receptor. This process is mediated by the sole oligosaccharide portion of GM1, the pentasaccharide ß-Gal-(1-3)-ß-GalNAc-(1-4)-[α-Neu5Ac-(2-3)]-ß-Gal-(1-4)-ß-Glc. Here we detailed the minimum structural requirements of the oligosaccharide portion of GM1 for mediating the TrkA dependent neuritogenic processing. By in vitro and in silico biochemical approaches, we demonstrated that the minimal portion of GM1 required for the TrkA activation is the inner core of the ganglioside's oligosaccharide ß-Gal-(1-3)-ß-GalNAc-(1-4)-[α-Neu5Ac-(2-3)]-ß-Gal. The addition of a sialic acid residue at position 3 of the outer galactose of the GM1 oligosaccharide, which forms the oligosaccharide of GD1a, prevented the interaction with TrkA and the resulting neuritogenesis. On the contrary, the addition of a fucose residue at position 2 of the outer galactose, forming the Fucosyl-GM1 oligosaccharide, did not prevent the TrkA-mediated neuritogenesis.


Assuntos
Gangliosídeo G(M1) , Galactose , Gangliosídeo G(M1)/química , Ácido N-Acetilneuramínico , Oligossacarídeos/química
5.
Int J Mol Sci ; 24(3)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36769028

RESUMO

The fulfilment of the European "Farm to Fork" strategy requires a drastic reduction in the use of "at risk" synthetic pesticides; this exposes vulnerable agricultural sectors-among which is the European risiculture-to the lack of efficient means for the management of devastating diseases, thus endangering food security. Therefore, novel scaffolds need to be identified for the synthesis of new and more environmentally friendly fungicides. In the present work, we employed our previously developed 3D model of P. oryzae cytochrome bc1 (cyt bc1) complex to perform a high-throughput virtual screening of two commercially available compound libraries. Three chemotypes were selected, from which a small collection of differently substituted analogues was designed and synthesized. The compounds were tested as inhibitors of the cyt bc1 enzyme function and the mycelium growth of both strobilurin-sensitive (WT) and -resistant (RES) P. oryzae strains. This pipeline has permitted the identification of thirteen compounds active against the RES cyt bc1 and five compounds that inhibited the WT cyt bc1 function while inhibiting the fungal mycelia only minimally. Serendipitously, among the studied compounds we identified a new chemotype that is able to efficiently inhibit the mycelium growth of WT and RES strains by ca. 60%, without inhibiting the cyt bc1 enzymatic function, suggesting a different mechanism of action.


Assuntos
Ascomicetos , Fungicidas Industriais , Citocromos b/metabolismo , Ascomicetos/metabolismo , Fungicidas Industriais/farmacologia , Estrobilurinas/farmacologia , Complexo III da Cadeia de Transporte de Elétrons
6.
Pharmacol Res ; 183: 106375, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35918045

RESUMO

Toxic aggregates of α-synuclein (αsyn) are considered key drivers of Parkinson's disease (PD) pathology. In early PD, αsyn induces synaptic dysfunction also modulating the glutamatergic neurotransmission. However, a more detailed understanding of the molecular mechanisms underlying αsyn-triggered synaptic failure is required to design novel therapeutic interventions. Here, we described the role of Rabphilin-3A (Rph3A) as novel target to counteract αsyn-induced synaptic loss in PD. Rph3A is a synaptic protein interacting with αsyn and involved in stabilizing dendritic spines and in promoting the synaptic retention of NMDA-type glutamate receptors. We found that in vivo intrastriatal injection of αsyn-preformed fibrils in mice induces the early loss of striatal synapses associated with decreased synaptic levels of Rph3A and impaired Rph3A/NMDA receptors interaction. Modulating Rph3A striatal expression or interfering with the Rph3A/αsyn complex with a small molecule prevented dendritic spine loss and rescued associated early motor defects in αsyn-injected mice. Notably, the same experimental approaches prevented αsyn-induced synaptic loss in vitro in primary hippocampal neurons. Overall, these findings indicate that approaches aimed at restoring Rph3A synaptic functions can slow down the early synaptic detrimental effects of αsyn aggregates in PD.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Camundongos , Proteínas do Tecido Nervoso , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Proteínas de Transporte Vesicular/metabolismo , alfa-Sinucleína/metabolismo , Rabfilina-3A
7.
Regul Toxicol Pharmacol ; 131: 105146, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35219763

RESUMO

On October 21-22, 2020 the HESI (Health and Environmental Sciences Institute) Protein Allergens, Toxins, and Bioinformatics Committee, and the Society of Toxicology Food Safety Specialty Section co-hosted a virtual workshop titled "From Protein Toxins to Applied Toxicological Testing". The workshop focused on the safety assessment of novel proteins contained in foods and feeds, was globally represented by over 200 stakeholder attendees, and featured contributions from experts in academia, government and non-government organizations, and agricultural biotechnology developers from the private sector. A range of topics relevant to novel protein safety were discussed, including: the state of protein toxin biology, modes and mechanisms of action, structures and activity, use of bioinformatic analyses to assess the safety of a protein, and ways to leverage computational biology with in silico approaches for protein toxin identification/characterization. Key outcomes of the workshop included the appreciation of the complexity of developing a definition for a protein toxin when viewed from the perspective of food and feed safety, confirming the need for a case-by-case hypothesis-driven interpretation of bioinformatic results that leverages additional metadata rather than an alignment threshold-driven interpretation, and agreement that a "toxin protein database" is not necessary, as the bioinformatic needs for toxin detection may be accomplished by existing databases such as Pfam and UniProtKB/Swiss-Prot. In this paper, a path forward is proposed.


Assuntos
Biologia Computacional , Inocuidade dos Alimentos , Alérgenos/química , Alérgenos/toxicidade , Biotecnologia/métodos , Bases de Dados de Proteínas
8.
Int J Mol Sci ; 23(14)2022 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-35886974

RESUMO

NONO and SFPQ are involved in multiple nuclear processes (e.g., pre-mRNA splicing, DNA repair, and transcriptional regulation). These proteins, along with NEAT1, enable paraspeckle formation, thus promoting multiple myeloma cell survival. In this paper, we investigate NONO and SFPQ dimer stability, highlighting the hetero- and homodimer structural differences, and model their interactions with RNA, simulating their binding to a polyG probe mimicking NEAT1guanine-rich regions. We demonstrated in silico that NONO::SFPQ heterodimerization is a more favorable process than homodimer formation. We also show that NONO and SFPQ RRM2 subunits are primarily required for protein-protein interactions with the other DBHS protomer. Simulation of RNA binding to NONO and SFPQ, beside validating RRM1 RNP signature importance, highlighted the role of ß2 and ß4 strand residues for RNA specific recognition. Moreover, we demonstrated the role of the NOPS region and other protomer's RRM2 ß2/ß3 loop in strengthening the interaction with RNA. Our results, having deepened RNA and DBHS dimer interactions, could contribute to the design of small molecules to modulate the activity of these proteins. RNA-mimetics, able to selectively bind to NONO and/or SFPQ RNA-recognition site, could impair paraspeckle formation, thus representing a first step towards the discovery of drugs for multiple myeloma treatment.


Assuntos
Proteínas de Ligação a DNA , Mieloma Múltiplo , Fator de Processamento Associado a PTB , RNA , Proteínas de Ligação a DNA/metabolismo , Dimerização , Humanos , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Fator de Processamento Associado a PTB/metabolismo , Subunidades Proteicas/metabolismo , RNA/metabolismo , Fatores de Processamento de RNA/metabolismo , Proteínas de Ligação a RNA/metabolismo
9.
Int J Mol Sci ; 24(1)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36613703

RESUMO

GPR17, a G protein-coupled receptor, is a pivotal regulator of myelination. Its endogenous ligands trigger receptor desensitization and downregulation allowing oligodendrocyte terminal maturation. In addition to its endogenous agonists, GPR17 could be promiscuously activated by pro-inflammatory oxysterols and chemokines released at demyelinating lesions. Herein, the chemokine receptors CXCR2 and CXCR4 were selected to perform both in silico modelling and in vitro experiments to establish their structural and functional interactions with GPR17. The relative propensity of GPR17 and CXCR2 or CXCR4 to form homo- and hetero-dimers was assessed by homology modelling and molecular dynamics (MD) simulations, and co-immunoprecipitation and immunoenzymatic assay. The interaction between chemokine receptors and GPR17 was investigated by determining receptor-mediated modulation of intracellular cyclic adenosine monophosphate (cAMP). Our data show the GPR17 association with CXCR2 or CXCR4 and the negative regulation of these interactions by CXCR agonists or antagonists. Moreover, GPR17 and CXCR2 heterodimers can functionally influence each other. In contrast, CXCR4 can influence GPR17 functionality, but not vice versa. According to MD simulations, all the dimers reached conformational stability and negative formation energy, confirming the experimental observations. The cross-talk between these receptors could play a role in the development of the neuroinflammatory milieu associated with demyelinating events.


Assuntos
Receptores de Quimiocinas , Receptores Acoplados a Proteínas G , Receptores Acoplados a Proteínas G/química , Transdução de Sinais/fisiologia , AMP Cíclico , Simulação de Dinâmica Molecular
10.
J Lipid Res ; 62: 100006, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33518511

RESUMO

Lecithin:cholesterol-acyl transferase (LCAT) plays a major role in cholesterol metabolism as it is the only extracellular enzyme able to esterify cholesterol. LCAT activity is required for lipoprotein remodeling and, most specifically, for the growth and maturation of HDLs. In fact, genetic alterations affecting LCAT functionality may cause a severe reduction in plasma levels of HDL-cholesterol with important clinical consequences. Although several hypotheses were formulated, the exact molecular recognition mechanism between LCAT and HDLs is still unknown. We employed a combination of structural bioinformatics procedures to deepen the insights into the HDL-LCAT interplay that promotes LCAT activation and cholesterol esterification. We have generated a data-driven model of reconstituted HDL (rHDL) and studied the dynamics of an assembled rHDL::LCAT supramolecular complex, pinpointing the conformational changes originating from the interaction between LCAT and apolipoprotein A-I (apoA-I) that are necessary for LCAT activation. Specifically, we propose a mechanism in which the anchoring of LCAT lid to apoA-I helices allows the formation of a hydrophobic hood that expands the LCAT active site and shields it from the solvent, allowing the enzyme to process large hydrophobic substrates.


Assuntos
Fosfatidilcolina-Esterol O-Aciltransferase
11.
Int J Mol Sci ; 22(7)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918510

RESUMO

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.


Assuntos
Ascomicetos , Farmacorresistência Fúngica , Fungicidas Industriais/síntese química , Estrobilurinas/química , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Succinato Desidrogenase/antagonistas & inibidores
12.
Molecules ; 24(12)2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31208066

RESUMO

Monoacylglycerol lipase (MAGL) is a serine hydrolase that has a key regulatory role in controlling the levels of 2-arachidonoylglycerol (2-AG), the main signaling molecule in the endocannabinoid system. Identification of selective modulators of MAGL enables both to provide new tools for investigating pathophysiological roles of 2-AG, and to discover new lead compounds for drug design. The development of sensitive and reliable methods is crucial to evaluate this modulatory activity. In the current study, we report readily synthesized long-wavelength putative fluorogenic substrates with different acylic side chains to find a new probe for MAGL activity. 7-Hydroxyresorufinyl octanoate proved to be the best substrate thanks to the highest rate of hydrolysis and the best Km and Vmax values. In addition, in silico evaluation of substrates interaction with the active site of MAGL confirms octanoate resorufine derivative as the molecule of choice. The well-known MAGL inhibitors URB602 and methyl arachidonylfluorophosphonate (MAFP) were used for the assay validation. The assay was highly reproducible with an overall average Z' value of 0.86. The fast, sensitive and accurate method described in this study is suitable for low-cost high-throughput screening (HTS) of MAGL modulators and is a powerful new tool for studying MAGL activity.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Corantes Fluorescentes , Ensaios de Triagem em Larga Escala , Monoacilglicerol Lipases/antagonistas & inibidores , Relação Dose-Resposta a Droga , Ensaios de Triagem em Larga Escala/métodos , Humanos , Hidrólise , Cinética , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Monoacilglicerol Lipases/química , Reprodutibilidade dos Testes , Relação Estrutura-Atividade
13.
Bioorg Med Chem ; 26(9): 2561-2572, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29678535

RESUMO

Monoacylglycerol lipase (MAGL) has an essential role in the catabolic pathway of the endocannabinoid 2-arachidonoylglycerol, which makes it a potential target for highly specific inhibitors for the treatment of a number of diseases. We designed and synthesized a series of carbamate analogues of URB602. We evaluated their inhibitory activity toward human MAGL in vitro both in cell culture and lysates. The target compounds exhibited moderate to excellent inhibitory activity against MAGL. The most promising compound 2b showed good inhibitory activity with IC50 value of 4.5 ±â€¯0.70 µM reducing MAGL activity to 82% of controls at 10 µM compared to 66% for the parent compound URB602. Interestingly, compounds 2b and 2c induce cell death through the inhibition of MAGL. Molecular modelling approaches and docking studies, used to investigate inhibitory profiles, indicated that trifluoromethyl substitutions of the aryl group and the benzene ring present at the oxygen side of the carbamate molecule had a significant impact on the activity.


Assuntos
Antineoplásicos/farmacologia , Carbamatos/farmacologia , Inibidores Enzimáticos/farmacologia , Monoacilglicerol Lipases/antagonistas & inibidores , Amidoidrolases/antagonistas & inibidores , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Sítios de Ligação , Compostos de Bifenilo/síntese química , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Carbamatos/síntese química , Carbamatos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios Enzimáticos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Células HEK293 , Humanos , Camundongos , Simulação de Acoplamento Molecular , Estrutura Molecular , Monoacilglicerol Lipases/química , Relação Estrutura-Atividade
14.
Arch Toxicol ; 92(12): 3471-3486, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30293151

RESUMO

Consumers are exposed to pesticide residues and other food contaminants via the diet. Both can exert adverse effects on different target organs via the activation of nuclear receptor pathways. Hepatotoxic effects of the widely used triazole fungicide propiconazole (Pi) are generally attributed to the activation of the constitutive androstane receptor (CAR) or the pregnane X receptor (PXR). We now investigated the effects of Pi on the aryl hydrocarbon receptor (AHR) and possible mixture toxicity when Pi is present in combination with BbF, an AHR ligand. In silico docking simulations indicate that Pi can bind to human AHR. Subsequent dual luciferase reporter gene assays in human HepG2 cells showed that Pi activates the AHR in vitro. This concentration-dependent activation was confirmed by real-time RT-PCR analyses of the model AHR target genes CYP1A1 and CYP1A2 in human HepaRG and HepG2 cells. In addition, induction of CYP1A1 protein levels and enzyme activity were recorded. Similarly, increased mRNA expression and enzyme activity of Cyp1a1 and Cyp1a2 was observed in livers of rats treated with Pi for 28 days via the diet. Gene expression analysis in AHR-knockout HepaRG cells showed no induction of CYP1A1 and CYP1A2, whereas gene expression in CAR-, and PXR-knockout cells was induced. Finally, mixture effects of Pi and BbF were analyzed in human cell lines: modeling of concentration-response curves revealed concentration additivity. In conclusion, our results demonstrate that the triazole Pi is an activator of AHR in silico, in vitro and in vivo and causes additive effects with an established AHR ligand.


Assuntos
Fluorenos/toxicidade , Receptores de Hidrocarboneto Arílico/efeitos dos fármacos , Receptores Citoplasmáticos e Nucleares/efeitos dos fármacos , Triazóis/toxicidade , Animais , Linhagem Celular , Simulação por Computador , Receptor Constitutivo de Androstano , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1A2/metabolismo , Relação Dose-Resposta a Droga , Fluorenos/administração & dosagem , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/toxicidade , Perfilação da Expressão Gênica/métodos , Técnicas de Inativação de Genes , Genes Reporter , Células Hep G2 , Humanos , Ligantes , Fígado/efeitos dos fármacos , Simulação de Acoplamento Molecular , Ratos , Ratos Wistar , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Triazóis/administração & dosagem
15.
J Neurochem ; 143(6): 645-659, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28796418

RESUMO

GM1 ganglioside (II3 NeuAc-Gg4 Cer) is known to promote neurite formation in neuroblastoma cells by activating TrkA-MAPK pathway. The molecular mechanism by which GM1 is involved in the neurodifferentiation process is still unknown, however, in vitro and in vivo evidences have suggested that the oligosaccharide portion of this ganglioside could be involved. Here, we report that, similarly to the entire GM1 molecule, its oligosaccharide II3 NeuAc-Gg4, rather than its ceramide (Cer) portion is responsible for the neurodifferentiation process by augmenting neurite elongation and increasing the neurofilament protein expression in murine neuroblastoma cells, Neuro2a. Conversely, asialo-GM1, GM2 and GM3 oligosaccharides are not effective in neurite elongation on Neuro2a cells, whereas the effect exerted by the Fuc-GM1 oligosaccharide (IV2 αFucII3 Neu5Ac-Gg4 ) is similar to that exerted by GM1 oligosaccharide. The neurotrophic properties of GM1 oligosaccharide are exerted by activating the TrkA receptor and the following phosphorylation cascade. By photolabeling experiments performed with a nitrophenylazide containing GM1 oligosaccharide, labeled with tritium, we showed a direct interaction between the GM1 oligosaccharide and the extracellular domain of TrkA receptor. Moreover, molecular docking analyses confirmed that GM1 oligosaccharide binds the TrkA-nerve growth factor complex leading to a binding free energy of approx. -11.5 kcal/mol, acting as a bridge able to increase and stabilize the TrkA-nerve growth factor molecular interactions.


Assuntos
Gangliosídeo G(M1)/metabolismo , Neuritos/metabolismo , Neuroblastoma , Receptor trkA/metabolismo , Animais , Diferenciação Celular/fisiologia , Linhagem Celular , Gangliosídeo G(M1)/química , Camundongos , Simulação de Acoplamento Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Transdução de Sinais/fisiologia
16.
Biochim Biophys Acta Gen Subj ; 1861(4): 727-736, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28088504

RESUMO

BACKGROUND: LAT1 (SLC7A5) is the transport competent unit of the heterodimer formed with the glycoprotein CD98 (SLC3A2). It catalyzes antiport of His and some neutral amino acids such as Ile, Leu, Val, Cys, Met, Gln and Phe thus being involved in amino acid metabolism. Interestingly, LAT1 is over-expressed in many human cancers that are characterized by increased demand of amino acids. Therefore LAT1 was recently acknowledged as a novel target for cancer therapy. However, knowledge on molecular mechanism of LAT1 transport is still scarce. METHODS: Combined approaches of bioinformatics, site-directed mutagenesis, chemical modification, and transport assay in proteoliposomes, have been adopted to unravel dark sides of human LAT1 structure/function relationships. RESULTS: It has been demonstrated that residues F252, S342, C335 are crucial for substrate recognition and C407 plays a minor role. C335 and C407 cannot be targeted by SH reagents. The transporter has a preferential dimeric structure and catalyzes an antiport reaction which follows a simultaneous random mechanism. CONCLUSIONS: Critical residues of the substrate binding site of LAT1 have been probed. This site is not freely accessible by molecules other than substrate. Similarly to LeuT, K+ has some regulatory properties on LAT1. GENERAL SIGNIFICANCE: The collected data represent a solid basis for deciphering molecular mechanism underlying LAT1 function.


Assuntos
Sistemas de Transporte de Aminoácidos/metabolismo , Aminoácidos/metabolismo , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Transporte Proteico/fisiologia , Sequência de Aminoácidos , Humanos , Transporte de Íons/fisiologia , Proteolipídeos/metabolismo , Alinhamento de Sequência
17.
Org Biomol Chem ; 14(13): 3404-8, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26952764

RESUMO

A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. Reduction of ortho-derivatives occurred only with substrates bearing substituents with low steric impact (i.e., F and CN). Reactivity was controlled by stereoelectronic features (C[double bond, length as m-dash]O length and charge, shape of LUMO frontier molecular orbitals), which can be theoretically calculated.


Assuntos
Acetofenonas/metabolismo , Oxirredutases do Álcool/metabolismo , Pichia/enzimologia , Acetofenonas/química , Oxirredutases do Álcool/química , Elétrons , Estrutura Molecular , Oxirredução , Estereoisomerismo , Especificidade por Substrato
18.
PLoS One ; 19(6): e0304512, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38829838

RESUMO

The Organic Cation Transporter Novel 1 (OCTN1), also known as SLC22A4, is widely expressed in various human tissues, and involved in numerous physiological and pathological processes remains. It facilitates the transport of organic cations, zwitterions, with selectivity for positively charged solutes. Ergothioneine, an antioxidant compound, and acetylcholine (Ach) are among its substrates. Given the lack of experimentally solved structures of this protein, this study aimed at generating a reliable 3D model of OCTN1 to shed light on its substrate-binding preferences and the role of sodium in substrate recognition and transport. A chimeric model was built by grafting the large extracellular loop 1 (EL1) from an AlphaFold-generated model onto a homology model. Molecular dynamics simulations revealed domain-specific mobility, with EL1 exhibiting the highest impact on overall stability. Molecular docking simulations identified cytarabine and verapamil as highest affinity ligands, consistent with their known inhibitory effects on OCTN1. Furthermore, MM/GBSA analysis allowed the categorization of substrates into weak, good, and strong binders, with molecular weight strongly correlating with binding affinity to the recognition site. Key recognition residues, including Tyr211, Glu381, and Arg469, were identified through interaction analysis. Ach demonstrated a low interaction energy, supporting the hypothesis of its one-directional transport towards to outside of the membrane. Regarding the role of sodium, our model suggested the involvement of Glu381 in sodium binding. Molecular dynamics simulations of systems at increasing levels of Na+ concentrations revealed increased sodium occupancy around Glu381, supporting experimental data associating Na+ concentration to molecule transport. In conclusion, this study provides valuable insights into the 3D structure of OCTN1, its substrate-binding preferences, and the role of sodium in the recognition. These findings contribute to the understanding of OCTN1 involvement in various physiological and pathological processes and may have implications for drug development and disease management.


Assuntos
Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Proteínas de Transporte de Cátions Orgânicos , Humanos , Proteínas de Transporte de Cátions Orgânicos/química , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Proteínas de Transporte de Cátions Orgânicos/genética , Simportadores/química , Simportadores/metabolismo , Sítios de Ligação , Ligação Proteica , Ergotioneína/química , Ergotioneína/metabolismo , Sódio/metabolismo , Sódio/química , Simulação por Computador , Acetilcolina/metabolismo , Acetilcolina/química , Ligantes
19.
Sci Rep ; 13(1): 1343, 2023 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-36823210

RESUMO

Stature is a biological trait directly determined by the interaction of genetic and environmental components. As such, it is often evaluated as an indicator for the reconstruction of skeletal biological profiles, past health, and social dynamics of human populations. Based on the analysis of 549 skeletons from the CAL (Collezione Antropologica LABANOF), a study of the diachronic trend of male and female adult stature in Milan (Italy) is being proposed here, covering a time span of about 2000 years, ranging from the Roman era to present-days. The skeletons, from necropolises dedicated to the less wealthy classes of Milanese society, were assigned to one of following five historical periods: Roman Era (first-fifth centuries AD), Early Middle Ages (sixth-tenth centuries AD), Late Middle Ages (eleventh-fifteenth centuries AD), Modern Era (sixteenth-eighteenth centuries AD) and Contemporary Era (nineteenth-twentieth centuries AD), and their stature was estimated according to the regression formulae of Trotter (1970). The collected data were then subjected to statistical analyses with ANOVA using R software. Although stature values showed an ample standard deviation in all periods, statistical analyses showed that stature did not significantly vary across historical periods in Milan for both sexes. This is one of the rare studies showing no diachronic changes in the trend of stature in Europe.


Assuntos
Estatura , Esqueleto , Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Europa (Continente) , Itália , Software
20.
Ann Med ; 55(1): 2205659, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37143345

RESUMO

AIM: The effect of liposomes bi-functionalized with phosphatidic acid and with a synthetic peptide derived from human apolipoprotein E has been evaluated on the aggregation features of different amyloidogenic proteins: human Amyloid ß1-40 (Aß1-40), transthyretin (TTR) variant S52P, human ß2microglobulin (ß2m) variants ΔN6 and D76N, Serum Amyloid A (SAA). METHODS: The formation of fibrillar aggregates of the proteins was investigated by ThioflavinT fluorescence assay and validated by Atomic Force Microscopy. RESULTS: The results show that liposomes are preventing the transition of non-aggregated forms to the fibrillar state, with stronger effects on Aß1-40, ß2m ΔN6 and SAA. Liposomes also induce disaggregation of the amyloid aggregates of all the proteins investigated, with stronger effects on Aß1-40, ß2 D76N and TTR.SPR assays show that liposomes bind Aß1-40 and SAA aggregates with high affinity (KD in the nanomolar range) whereas binding to TTR aggregates showed a lower affinity (KD in the micromolar range). Aggregates of ß2m variants showed both high and low affinity binding sites. Computed Structural analysis of protein fibrillar aggregates and considerations on the multidentate features of liposomes allow to speculate a common mechanism of action, based on binding the ß-stranded peptide regions responsible for the amyloid formation. CONCLUSION: Thus, multifunctional liposomes perform as pharmacological chaperones with anti-amyloidogenic activity, with a promising potential for the treatment of a number of protein-misfolding diseases.Key messageAmyloidosis is a group of diseases, each due to a specific protein misfolding.Anti-amyloidogenic nanoparticles have been gaining the utmost importance as a potential treatment for protein misfolding disorders.Liposomes bi-functionalized with phosphatidic acid and with a synthetic peptide derived from human apolipoprotein E showed anti-amyloidogenic activity.


Assuntos
Amiloide , Lipossomos , Humanos , Amiloide/química , Amiloide/metabolismo , Agregados Proteicos , Chaperonas Moleculares , Ácidos Fosfatídicos , Apolipoproteínas
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