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1.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360989

RESUMO

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer's disease (AD), the major form of dementia, ß-amyloid (Aß) levels in the blood are increased; however, the impact of elevated Aß levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aß1-42, but not Aß1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aß1-42. Furthermore, Aß1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aß1-42 show that the clearance of Aß1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aß antibody. In conclusion, these findings suggest that the binding of Aß1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aß1-42 in the blood is beneficial to the fight against COVID-19 and AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Enzima de Conversão de Angiotensina 2/metabolismo , Fragmentos de Peptídeos/metabolismo , SARS-CoV-2/enzimologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Células A549 , Doença de Alzheimer/complicações , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/química , Animais , COVID-19/complicações , COVID-19/metabolismo , Chlorocebus aethiops , Humanos , Interleucina-6/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fragmentos de Peptídeos/química , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Células Vero , Internalização do Vírus
2.
Viruses ; 13(8)2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34452531

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic causing over 195 million infections and more than 4 million fatalities as of July 2021.To date, it has been demonstrated that a number of mutations in the spike glycoprotein (S protein) of SARS-CoV-2 variants of concern abrogate or reduce the neutralization potency of several therapeutic antibodies and vaccine-elicited antibodies. Therefore, the development of additional vaccine platforms with improved supply and logistic profile remains a pressing need. In this work, we have validated the applicability of a peptide-based strategy focused on a preventive as well as a therapeutic purpose. On the basis of the involvement of the dipeptidyl peptidase 4 (DPP4), in addition to the angiotensin converting enzyme 2 (ACE2) receptor in the mechanism of virus entry, we analyzed peptides bearing DPP4 sequences by protein-protein docking and assessed their ability to block pseudovirus infection in vitro. In parallel, we have selected and synthetized peptide sequences located within the highly conserved receptor-binding domain (RBD) of the S protein, and we found that RBD-based vaccines could better promote elicitation of high titers of neutralizing antibodies specific against the regions of interest, as confirmed by immunoinformatic methodologies and in vivo studies. These findings unveil a key antigenic site targeted by broadly neutralizing antibodies and pave the way to the design of pan-coronavirus vaccines.


Assuntos
Dipeptidil Peptidase 4/química , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/farmacologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/tratamento farmacológico , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Chlorocebus aethiops , Dipeptidil Peptidase 4/metabolismo , Epitopos de Linfócito T/imunologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Domínios Proteicos , Receptores de Coronavírus/química , Receptores de Coronavírus/metabolismo , SARS-CoV-2/química , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Células Vero , Internalização do Vírus
3.
Science ; 373(6558): 1040-1046, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34446607

RESUMO

The antitumor efficacy of cancer immunotherapy can correlate with the presence of certain bacterial species within the gut microbiome. However, many of the molecular mechanisms that influence host response to immunotherapy remain elusive. In this study, we show that members of the bacterial genus Enterococcus improve checkpoint inhibitor immunotherapy in mouse tumor models. Active enterococci express and secrete orthologs of the NlpC/p60 peptidoglycan hydrolase SagA that generate immune-active muropeptides. Expression of SagA in nonprotective E. faecalis was sufficient to promote immunotherapy response, and its activity required the peptidoglycan sensor NOD2. Notably, SagA-engineered probiotics or synthetic muropeptides also augmented anti-PD-L1 antitumor efficacy. Taken together, our data suggest that microbiota species with specialized peptidoglycan remodeling activity and muropeptide-based therapeutics may enhance cancer immunotherapy and could be leveraged as next-generation adjuvants.


Assuntos
Antígeno B7-H1/antagonistas & inibidores , Enterococcus/metabolismo , Inibidores de Checkpoint Imunológico/uso terapêutico , Melanoma Experimental/terapia , N-Acetil-Muramil-L-Alanina Amidase/metabolismo , Peptidoglicano/metabolismo , Animais , Carga Bacteriana , Proteínas de Bactérias/metabolismo , Enterococcus/enzimologia , Enterococcus faecalis/metabolismo , Enterococcus faecium/metabolismo , Microbioma Gastrointestinal , Imunoterapia , Melanoma Experimental/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Proteína Adaptadora de Sinalização NOD2/metabolismo , Fragmentos de Peptídeos/metabolismo , Probióticos , Transdução de Sinais
4.
Adv Biol Regul ; 81: 100820, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34419773

RESUMO

The article describes the possible pathophysiological origin of COVID-19 and the crucial role of renin-angiotensin system (RAS), providing several "converging" evidence in support of this hypothesis. SARS-CoV-2 has been shown to initially upregulate ACE2 systemic activity (early phase), which can subsequently induce compensatory responses leading to upregulation of both arms of the RAS (late phase) and consequently to critical, advanced and untreatable stages of COVID-19 disease. The main and initial actors of the process are ACE2 and ADAM17 zinc-metalloproteases, which, initially triggered by SARS-CoV-2 spike proteins, work together in increasing circulating Ang 1-7 and Ang 1-9 peptides and downstream (Mas and Angiotensin type 2 receptors) pathways with anti-inflammatory, hypotensive and antithrombotic activities. During the late phase of severe COVID-19, compensatory secretion of renin and ACE enzymes are subsequently upregulated, leading to inflammation, hypertension and thrombosis, which further sustain ACE2 and ADAM17 upregulation. Based on this hypothesis, COVID-19-phase-specific inhibition of different RAS enzymes is proposed as a pharmacological strategy against COVID-19 and vaccine-induced adverse effects. The aim is to prevent the establishment of positive feedback-loops, which can sustain hyperactivity of both arms of the RAS independently of viral trigger and, in some cases, may lead to Long-COVID syndrome.


Assuntos
Proteína ADAM17/biossíntese , Enzima de Conversão de Angiotensina 2/biossíntese , COVID-19/metabolismo , Sistema Renina-Angiotensina , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Proteína ADAM17/antagonistas & inibidores , Angiotensina I/metabolismo , Enzima de Conversão de Angiotensina 2/antagonistas & inibidores , COVID-19/tratamento farmacológico , Regulação Enzimológica da Expressão Gênica , Humanos , Fragmentos de Peptídeos/metabolismo , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Regulação para Cima
5.
Inorg Chem ; 60(17): 13669-13680, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34424670

RESUMO

Alzheimer's disease (AD) is associated with the presence of amyloid plaques in the brain mainly comprised of aggregated forms of amyloid-ß (Aß). Molecules radiolabeled with technetium-99m that cross the blood-brain barrier (BBB) and selectively bind to Aß plaques have the potential to assist in the diagnosis of AD using single-photon emission computed tomography imaging. In this work, three new tetradentate ligands of pyridyl, amide, amine and thiol donors, featuring a styrylpyridyl group that is known to interact with amyloid plaques, were prepared. The new ligands formed charge-neutral and lipophilic complexes with the [Tc═O]3+ and [Re═O]3+ motifs, and two rhenium complexes were characterized by X-ray crystallography. The rhenium(V) complexes interact with synthetic Aß1-40 and amyloid plaques on human brain tissue. Two of the new ligands were radiolabeled with 99mTc using a kit-based approach, and their biodistribution in wild-type mice was evaluated. The presence of amide donors in the tetradentate ligand increased the stability of the respective [Tc═O]3+ complexes but reduced brain uptake. While the complexes were able to cross the BBB, the degree of uptake in the brain was not sufficient to justify further investigation of these complexes.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Complexos de Coordenação/química , Compostos de Organotecnécio/química , Compostos Radiofarmacêuticos/química , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Complexos de Coordenação/síntese química , Complexos de Coordenação/metabolismo , Complexos de Coordenação/farmacocinética , Humanos , Ligantes , Camundongos , Compostos de Organotecnécio/síntese química , Compostos de Organotecnécio/metabolismo , Compostos de Organotecnécio/farmacocinética , Fragmentos de Peptídeos/metabolismo , Piridinas/síntese química , Piridinas/química , Piridinas/metabolismo , Piridinas/farmacocinética , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/metabolismo , Compostos Radiofarmacêuticos/farmacocinética , Rênio/química , Estirenos/síntese química , Estirenos/química , Estirenos/metabolismo , Estirenos/farmacocinética
6.
Biomolecules ; 11(7)2021 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-34356604

RESUMO

Alzheimer's disease (AD), a progressive neurodegenerative disease, affects approximately 50 million people worldwide, which warrants the search for reliable new biomarkers for early diagnosis of AD. Brain-derived exosomal (BDE) proteins, which are extracellular nanovesicles released by all cell lineages of the central nervous system, have been focused as biomarkers for diagnosis, screening, prognosis prediction, and monitoring in AD. This review focused on the possibility of BDE proteins as AD biomarkers. The articles published prior to 26 January 2021 were searched in PubMed, EMBASE, Web of Science, and Cochrane Library to identify all relevant studies that reported exosome biomarkers in blood samples of patients with AD. From 342 articles, 20 studies were selected for analysis. We conducted a meta-analysis of six BDE proteins and found that levels of amyloid-ß42 (standardized mean difference (SMD) = 1.534, 95% confidence interval [CI]: 0.595-2.474), total-tau (SMD = 1.224, 95% CI: 0.534-1.915), tau phosphorylated at threonine 181 (SMD = 4.038, 95% CI: 2.312-5.764), and tau phosphorylated at serine 396 (SMD = 2.511, 95% CI: 0.795-4.227) were significantly different in patients with AD compared to those in control. Whereas, those of p-tyrosine-insulin receptor substrate-1 and heat shock protein 70 did not show significant differences. This review suggested that Aß42, t-tau, p-T181-tau, and p-S396-tau could be effective in diagnosing AD as blood biomarkers, despite the limitation in the meta-analysis based on the availability of data. Therefore, certain BDE proteins could be used as effective biomarkers for AD.


Assuntos
Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Exossomos/metabolismo , Peptídeos beta-Amiloides/metabolismo , Biomarcadores/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Proteínas Substratos do Receptor de Insulina/metabolismo , Fragmentos de Peptídeos/metabolismo , Proteínas tau/metabolismo
7.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34360576

RESUMO

Noncoding RNAs have been known to contribute to a variety of fundamental life processes, such as development, metabolism, and circadian rhythms. However, much remains unrevealed in the huge noncoding RNA datasets, which require further bioinformatic analysis and experimental investigation-and in particular, the coding potential of lncRNAs and the functions of lncRNA-encoded peptides have not been comprehensively studied to date. Through integrating the time-course experimentation with state-of-the-art computational techniques, we studied tens of thousands of zebrafish lncRNAs from our own experiments and from a published study including time-series transcriptome analyses of the testis and the pineal gland. Rhythmicity analysis of these data revealed approximately 700 rhythmically expressed lncRNAs from the pineal gland and the testis, and their GO, COG, and KEGG pathway functions were analyzed. Comparative and conservative analyses determined 14 rhythmically expressed lncRNAs shared between both the pineal gland and the testis, and 15 pineal gland lncRNAs as well as 3 testis lncRNAs conserved among zebrafish, mice, and humans. Further, we computationally analyzed the conserved lncRNA-encoded peptides, and revealed three pineal gland and one testis lncRNA-encoded peptides conserved among these three species, which were further investigated for their three-dimensional (3D) structures and potential functions. Our computational findings provided novel annotations and regulatory mechanisms for hundreds of rhythmically expressed pineal gland and testis lncRNAs in zebrafish, and set the stage for their experimental studies in the near future.


Assuntos
Ritmo Circadiano , Glândula Pineal/metabolismo , RNA Longo não Codificante/genética , Testículo/metabolismo , Transcriptoma , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/genética , Animais , Biologia Computacional , Perfilação da Expressão Gênica , Masculino , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/genética
8.
Nutrients ; 13(7)2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34371878

RESUMO

Alzheimer's disease (AD) is characterized by the aberrant processing of amyloid precursor protein (APP) and the accumulation of hyperphosphorylated tau, both of which are accompanied by neuroinflammation. Dietary supplementation with spray-dried porcine plasma (SDP) has anti-inflammatory effects in inflammation models. We investigated whether dietary supplementation with SDP prevents the neuropathological features of AD. The experiments were performed in 2- and 6-month-old SAMP8 mice fed a control diet, or a diet supplemented with 8% SDP, for 4 months. AD brain molecular markers were determined by Western blot and real-time PCR. Senescent mice showed reduced levels of p-GSK3ß (Ser9) and an increase in p-CDK5, p-tau (Ser396), sAPPß, and the concentration of Aß40, (all p < 0.05). SDP prevented these effects of aging and reduced Bace1 levels (all p < 0.05). Senescence increased the expression of Mme1 and Ide1 and pro-inflammatory cytokines (Il-17 and Il-18; all p < 0.05); these changes were prevented by SDP supplementation. Moreover, SDP increased Tgf-ß expression (p < 0.05). Furthermore, in aged mice, the gene expression levels of the microglial activation markers Trem2, Ym1, and Arg1 were increased, and SDP prevented these increases (all p < 0.05). Thus, dietary SDP might delay AD onset by reducing its hallmarks in senescent mice.


Assuntos
Doença de Alzheimer/prevenção & controle , Encéfalo/efeitos dos fármacos , Suplementos Nutricionais , Plasma , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Ração Animal , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Quinase 5 Dependente de Ciclina/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/metabolismo , Mediadores da Inflamação/metabolismo , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Emaranhados Neurofibrilares/efeitos dos fármacos , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Fragmentos de Peptídeos/metabolismo , Fosforilação , Transdução de Sinais , Secagem por Atomização , Sus scrofa , Proteínas tau/metabolismo
9.
Int J Mol Sci ; 22(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34209299

RESUMO

Alzheimer's disease (AD)-associated neurodegeneration is triggered by different fragments of amyloid beta (Aß). Among them, Aß (25-35) fragment plays a critical role in the development of neurodegeneration-it reduces synaptic integrity by disruption of excitatory/inhibitory ratio across networks and alters the growth factors synthesis. Thus, in this study, we aimed to identify the involvement of neurotrophic factors-the insulin-like growth factor 1 (IGF-1) and nerve growth factor (NGF)-of AD-like neurodegeneration induced by Aß (25-35). Taking into account our previous findings on the neuroprotective effects of the mix of proteoglycans of embryonic genesis (PEG), it was suggested to test its regulatory effect on IGF-1 and NGF levels. To evaluate the progress of neurodegeneration, in vivo electrophysiological investigation of synaptic activity disruption of the entorhinal cortex-hippocampus circuit at AD was performed and the potential recovery effects of PEG with relative structural changes were provided. To reveal the direct effects of PEG on brain functional activity, the electrophysiological pattern of the single cells from nucleus supraopticus, sensomotor cortex and hippocampus after acute injection of PEG was examined. Our results demonstrated that after i.c.v. injection of Aß (25-35), the level of NGF decreased in cerebral cortex and hypothalamus, and, in contrast, increased in hippocampus, prompting its multidirectional role in case of brain damage. The concentration of IGF-1 significantly increased in all investigated brain structures. The administration of PEG balanced the growth factor levels accompanied by substantial restoration of neural tissue architecture and synaptic activity. Acute injection of PEG activated the hypothalamic nucleus supraopticus and hippocampal neurons. IGF-1 and NGF levels were found to be elevated in animals receiving PEG in an absence of amyloid exposure. We suggest that IGF-1 and NGF play a critical role in the development of AD. At the same time, it becomes clear that the neuroprotective effects of PEG are likely mediated via the regulation of neurotrophins.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/metabolismo , Encéfalo , Eletrocardiografia , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Neural/metabolismo , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/fisiopatologia , Masculino , Ratos , Ratos Sprague-Dawley
10.
Biomolecules ; 11(6)2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207317

RESUMO

One of the treatment strategies for Alzheimer's disease (AD) is based on the use of pharmacological agents capable of binding to beta-amyloid (Aß) and blocking its aggregation in the brain. Previously, we found that intravenous administration of the synthetic tetrapeptide Acetyl-His-Ala-Glu-Glu-Amide (HAEE), which is an analogue of the 35-38 region of the α4 subunit of α4ß2 nicotinic acetylcholine receptor and specifically binds to the 11-14 site of Aß, reduced the development of cerebral amyloidogenesis in a mouse model of AD. In the current study on three types of laboratory animals, we determined the biodistribution and tissue localization patterns of HAEE peptide after single intravenous bolus administration. The pharmacokinetic parameters of HAEE were established using uniformly tritium-labeled HAEE. Pharmacokinetic data provided evidence that HAEE goes through the blood-brain barrier. Based on molecular modeling, a role of LRP1 in receptor-mediated transcytosis of HAEE was proposed. Altogether, the results obtained indicate that the anti-amyloid effect of HAEE, previously found in a mouse model of AD, most likely occurs due to its interaction with Aß species directly in the brain.


Assuntos
Peptídeos/farmacologia , Peptídeos/farmacocinética , Receptores Nicotínicos/genética , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/efeitos dos fármacos , Peptídeos beta-Amiloides/metabolismo , Animais , Transporte Biológico , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptídeos/genética , Coelhos , Ratos , Ratos Wistar , Receptores Nicotínicos/fisiologia
11.
J Chem Phys ; 154(23): 235102, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34241272

RESUMO

We compared all-atom explicit solvent molecular dynamics simulations of three types of Aß(1-40) fibrils: brain-seeded fibrils (2M4J, with a threefold axial symmetry) and the other two, all-synthetic fibril polymorphs (2LMN and 2LMP, made under different fibrillization conditions). Fibril models were constructed using either a finite or an infinite number of layers made using periodic images. These studies yielded four conclusions. First, finite fibrils tend to unravel in a manner reminiscent of fibril dissolution, while infinite fibrils were more stable during simulations. Second, salt bridges in these fibrils remained stable in those fibrils that contained them initially, and those without salt bridges did not develop them over the time course of the simulations. Third, all fibrils tended to develop a "stagger" or register shift of ß-strands along the fibril axis. Fourth and most importantly, the brain-seeded, 2M4J, infinite fibrils allowed bidirectional transport of water in and out of the central longitudinal core of the fibril by rapidly developing gaps at the fibril vertices. 2LMP fibrils also showed this behavior, although to a lesser extent. The diffusion of water molecules in the fibril core region involved two dynamical states: a localized state and directed diffusion in the presence of obstacles. These observations provided support for the hypothesis that Aß fibrils could act as nanotubes. At least some Aß oligomers resembled fibrils structurally in having parallel, in-register ß-sheets and a sheet-turn-sheet motif. Thus, our findings could have implications for Aß cytotoxicity, which may occur through the ability of oligomers to form abnormal water and ion channels in cell membranes.


Assuntos
Peptídeos beta-Amiloides/química , Simulação de Dinâmica Molecular , Fragmentos de Peptídeos/química , Água/química , Peptídeos beta-Amiloides/metabolismo , Fragmentos de Peptídeos/metabolismo , Água/metabolismo
12.
Cell Physiol Biochem ; 55(S3): 157-170, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34318654

RESUMO

BACKGROUND/AIMS: The Amyloid Precursor Protein (APP) is involved in the regulation of multiple cellular functions via protein-protein interactions and has been most studied with respect to Alzheimer's disease (AD). Abnormal processing of the single transmembrane-spanning C99 fragment of APP contributes to the formation of amyloid plaques, which are causally related to AD. Pathological C99 accumulation is thought to associate with early cognitive defects in AD. Here, unexpectedly, sequence analysis revealed that C99 exhibits 24% sequence identity with the KCNE1 voltage-gated potassium (Kv) channel ß subunit, comparable to the identity between KCNE1 and KCNE2-5 (21-30%). This suggested the possibility of C99 regulating Kv channels. METHODS: We quantified the effects of C99 on Kv channel function, using electrophysiological analysis of subunits expressed in Xenopus laevis oocytes, biochemical and immunofluorescence techniques. RESULTS: C99 isoform-selectively inhibited (by 30-80%) activity of a range of Kv channels. Among the KCNQ (Kv7) family, C99 isoform-selectively inhibited, shifted the voltage dependence and/or slowed activation of KCNQ2, KCNQ3, KCNQ2/3 and KCNQ5, with no effects on KCNQ1, KCNQ1-KCNE1 or KCNQ4. C99/APP co-localized with KCNQ2 and KCNQ3 in adult rat sciatic nerve nodes of Ranvier. Both C99 and full-length APP co-immunoprecipitated with KCNQ2 in vitro, yet unlike C99, APP only weakly affected KCNQ2/3 activity. Finally, C99 altered the effects on KCNQ2/3 function of inhibitors tetraethylammounium and XE991, but not openers retigabine and ICA27243. CONCLUSION: Our findings raise the possibility of C99 accumulation early in AD altering cellular excitability by modulating Kv channel activity.


Assuntos
Precursor de Proteína beta-Amiloide/farmacologia , Canais de Potássio KCNQ/genética , Canal de Potássio KCNQ2/genética , Canal de Potássio KCNQ3/genética , Fragmentos de Peptídeos/farmacologia , Sequência de Aminoácidos , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Antracenos/farmacologia , Expressão Gênica , Humanos , Canais de Potássio KCNQ/metabolismo , Canal de Potássio KCNQ2/metabolismo , Canal de Potássio KCNQ3/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Oócitos/citologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Técnicas de Patch-Clamp , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Nós Neurofibrosos/efeitos dos fármacos , Nós Neurofibrosos/metabolismo , Ratos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Tetraetilamônio/farmacologia , Xenopus laevis
13.
Am J Physiol Lung Cell Mol Physiol ; 321(2): L485-L489, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34231390

RESUMO

COVID-19, the disease caused by the SARS-CoV-2 virus, can progress to multisystem organ failure and viral sepsis characterized by respiratory failure, arrhythmias, thromboembolic complications, and shock with high mortality. Autopsy and preclinical evidence implicate aberrant complement activation in endothelial injury and organ failure. Erythrocytes express complement receptors and are capable of binding immune complexes; therefore, we investigated complement activation in patients with COVID-19 using erythrocytes as a tool to diagnose complement activation. We discovered enhanced C3b and C4d deposition on erythrocytes in COVID-19 sepsis patients and non-COVID sepsis patients compared with healthy controls, supporting the role of complement in sepsis-associated organ injury. Our data suggest that erythrocytes may contribute to a precision medicine approach to sepsis and have diagnostic value in monitoring complement dysregulation in COVID-19-sepsis and non-COVID sepsis and identifying patients who may benefit from complement targeted therapies.


Assuntos
COVID-19/complicações , Ativação do Complemento/imunologia , Complemento C3b/imunologia , Complemento C4b/imunologia , Eritrócitos/imunologia , Fragmentos de Peptídeos/imunologia , Insuficiência Respiratória/diagnóstico , Sepse/diagnóstico , COVID-19/imunologia , COVID-19/virologia , Complemento C3b/metabolismo , Complemento C4b/metabolismo , Eritrócitos/metabolismo , Eritrócitos/virologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/metabolismo , Insuficiência Respiratória/imunologia , Insuficiência Respiratória/metabolismo , Insuficiência Respiratória/virologia , SARS-CoV-2/isolamento & purificação , Sepse/imunologia , Sepse/metabolismo , Sepse/virologia
14.
Biomolecules ; 11(7)2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202467

RESUMO

Alzheimer's disease is the most common progressive neurodegenerative disorder and is characterized by the presence of amyloid ß (Aß) plaques in the brain. The γ-secretase complex, which produces Aß, is an intramembrane-cleaving protease consisting of four membrane proteins. In this paper we investigated the amyloidogenic fragments of amyloid precursor protein (substrates Aß43 and Aß45, leading to less amyloidogenic Aß40 and more amyloidogenic Aß42, respectively) docked to the binding site of presenilin, the catalytic subunit of γ-secretase. In total, we performed 9 µs of all-atom molecular dynamics simulations of the whole γ-secretase complex with both substrates in low (10%) and high (50%) concentrations of cholesterol in the membrane. We found that, at the high cholesterol level, the Aß45 helix was statistically more flexible in the binding site of presenilin than Aß43. An increase in the cholesterol concentration was also correlated with a higher flexibility of the Aß45 helix, which suggests incompatibility between Aß45 and the binding site of presenilin potentiated by a high cholesterol level. However, at the C-terminal part of Aß45, the active site of presenilin was more compact in the case of a high cholesterol level, which could promote processing of this substrate. We also performed detailed mapping of the cholesterol binding sites at low and high cholesterol concentrations, which were independent of the typical cholesterol binding motifs.


Assuntos
Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Colesterol/química , Colesterol/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Secretases da Proteína Precursora do Amiloide/genética , Peptídeos beta-Amiloides/genética , Colesterol/genética , Humanos , Simulação de Acoplamento Molecular , Fragmentos de Peptídeos/genética , Ligação Proteica/fisiologia , Estrutura Secundária de Proteína , Especificidade por Substrato
15.
Commun Biol ; 4(1): 870, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267322

RESUMO

The role of oligodendrocyte lineage cells, the largest glial population in the adult central nervous system (CNS), in the pathogenesis of Alzheimer's disease (AD) remains elusive. Here, we developed a culture method for adult oligodendrocyte progenitor cells (aOPCs). Fibroblast growth factor 2 (FGF2) promotes survival and proliferation of NG2+ aOPCs in a serum-free defined medium; a subpopulation (~5%) of plexin-B3+ aOPCs was also found. FGF2 withdrawal decreased NG2+, but increased plexin-B3+ aOPCs and Aß1-42 secretion. Plexin-B3+ aOPCs were distributed throughout the adult rat brain, although less densely than NG2+ aOPCs. Spreading depolarization induced delayed cortical plexin-B3+ aOPC gliosis in the ipsilateral remote cortex. Furthermore, extracellular Aß1-42 accumulation was occasionally found around plexin-B3+ aOPCs near the lesions. In AD brains, virtually all cortical SPs were immunostained for plexin-B3, and plexin-B3 levels increased significantly in the Sarkosyl-soluble fractions. These findings suggest that plexin-B3+ aOPCs may play essential roles in AD pathogenesis, as natural Aß-secreting cells.


Assuntos
Doença de Alzheimer/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Células Precursoras de Oligodendrócitos/metabolismo , Oligodendroglia/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Antígenos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Células Cultivadas , Feminino , Humanos , Masculino , Moléculas de Adesão de Célula Nervosa/metabolismo , Células Precursoras de Oligodendrócitos/citologia , Oligodendroglia/citologia , Fragmentos de Peptídeos/metabolismo , Proteoglicanas/metabolismo , Ratos Sprague-Dawley
16.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201610

RESUMO

The accumulation of aggregated protein is a typical hallmark of many human neurodegenerative disorders, including polyglutamine-related diseases such as chorea Huntington. Misfolding of the amyloidogenic proteins gives rise to self-assembled complexes and fibres. The huntingtin protein is characterised by a segment of consecutive glutamines which, when exceeding ~ 37 residues, results in the occurrence of the disease. Furthermore, it has also been demonstrated that the 17-residue amino-terminal domain of the protein (htt17), located upstream of this polyglutamine tract, strongly correlates with aggregate formation and pathology. Here, we demonstrate that membrane interactions strongly accelerate the oligomerisation and ß-amyloid fibril formation of htt17-polyglutamine segments. By using a combination of biophysical approaches, the kinetics of fibre formation is investigated and found to be strongly dependent on the presence of lipids, the length of the polyQ expansion, and the polypeptide-to-lipid ratio. Finally, the implications for therapeutic approaches are discussed.


Assuntos
Membrana Celular/metabolismo , Proteína Huntingtina/metabolismo , Peptídeos/metabolismo , Benzotiazóis/química , Dicroísmo Circular , Difusão Dinâmica da Luz , Éxons , Fluorescência , Humanos , Proteína Huntingtina/química , Proteína Huntingtina/genética , Bicamadas Lipídicas , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Peptídeos/química
17.
Molecules ; 26(12)2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204651

RESUMO

The driving forces and conformational pathways leading to amphitropic protein-membrane binding and in some cases also to protein misfolding and aggregation is the subject of intensive research. In this study, a chimeric polypeptide, A-Cage-C, derived from α-Lactalbumin is investigated with the aim of elucidating conformational changes promoting interaction with bilayers. From previous studies, it is known that A-Cage-C causes membrane leakages associated with the sporadic formation of amorphous aggregates on solid-supported bilayers. Here we express and purify double-labelled A-Cage-C and prepare partially deuterated bicelles as a membrane mimicking system. We investigate A-Cage-C in the presence and absence of these bicelles at non-binding (pH 7.0) and binding (pH 4.5) conditions. Using in silico analyses, NMR, conformational clustering, and Molecular Dynamics, we provide tentative insights into the conformations of bound and unbound A-Cage-C. The conformation of each state is dynamic and samples a large amount of overlapping conformational space. We identify one of the clusters as likely representing the binding conformation and conclude tentatively that the unfolding around the central W23 segment and its reorientation may be necessary for full intercalation at binding conditions (pH 4.5). We also see evidence for an overall elongation of A-Cage-C in the presence of model bilayers.


Assuntos
Proteína Oncogênica pp60(v-src)/química , Fragmentos de Peptídeos/química , Peptídeos/química , Lactalbumina/química , Espectroscopia de Ressonância Magnética/métodos , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Membranas , Simulação de Dinâmica Molecular , Proteína Oncogênica pp60(v-src)/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica
18.
Int J Mol Sci ; 22(11)2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34206089

RESUMO

Amyloid-ß (Aß) 1-40 and 1-42 peptides are key mediators of synaptic and cognitive dysfunction in Alzheimer's disease (AD). Whereas in AD, Aß is found to act as a pro-epileptogenic factor even before plaque formation, amyloid pathology has been detected among patients with epilepsy with increased risk of developing AD. Among Aß aggregated species, soluble oligomers are suggested to be responsible for most of Aß's toxic effects. Aß oligomers exert extracellular and intracellular toxicity through different mechanisms, including interaction with membrane receptors and the formation of ion-permeable channels in cellular membranes. These damages, linked to an unbalance between excitatory and inhibitory neurotransmission, often result in neuronal hyperexcitability and neural circuit dysfunction, which in turn increase Aß deposition and facilitate neurodegeneration, resulting in an Aß-driven vicious loop. In this review, we summarize the most representative literature on the effects that oligomeric Aß induces on synaptic dysfunction and network disorganization.


Assuntos
Doença de Alzheimer/genética , Peptídeos beta-Amiloides/genética , Sinapses/genética , Transmissão Sináptica/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/efeitos adversos , Peptídeos beta-Amiloides/ultraestrutura , Proteínas Amiloidogênicas/efeitos adversos , Proteínas Amiloidogênicas/genética , Animais , Humanos , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Multimerização Proteica/genética , Sinapses/metabolismo
19.
Molecules ; 26(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34201982

RESUMO

During the last three decades, a variety of different studies on bioactive peptides that are opioid receptor ligands, have been carried out, with regard to their isolation and identification, as well as their molecular functions in living organisms. Thus, in this review, we would like to summarize the present state-of-the art concerning hemorphins, methodological aspects of their identification, and their potential role as therapeutic agents. We have collected and discussed articles describing hemorphins, from their discovery up until now, thus presenting a very wide spectrum of their characteristic and applications. One of the major assets of the present paper is a combination of analytical and pharmacological aspects of peptides described by a team who participated in the initial research on hemorphins. This review is, in part, focused on the analysis of endogenous opioid peptides in biological samples using advanced techniques, description of the identification of synthetic/endogenous hemorphins, their involvement in pharmacology, learning, pain and other function. Finally, the part regarding hemorphin analogues and their synthesis, has been added.


Assuntos
Peptídeos Opioides/metabolismo , Dor/metabolismo , Fragmentos de Peptídeos/metabolismo , Receptores Opioides/metabolismo , Animais , Humanos
20.
Nutrients ; 13(6)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204378

RESUMO

In patients with phenylketonuria (PKU), treated by diet therapy only, evidence suggests that areal bone mineral density (BMDa) is within the normal clinical reference range but is below the population norm. AIMS: To study longitudinal bone density, mass, and geometry over 36 months in children with PKU taking either amino acid (L-AA) or casein glycomacropeptide substitutes (CGMP-AA) as their main protein source. METHODOLOGY: A total of 48 subjects completed the study, 19 subjects in the L-AA group (median age 11.1, range 5-16 years) and 29 subjects in the CGMP-AA group (median age 8.3, range 5-16 years). The CGMP-AA was further divided into two groups, CGMP100 (median age 9.2, range 5-16 years) (n = 13), children taking CGMP-AA only and CGMP50 (median age 7.3, range 5-15 years) (n = 16), children taking a combination of CGMP-AA and L-AA. Dual X-ray absorptiometry (DXA) was measured at enrolment and 36 months, peripheral quantitative computer tomography (pQCT) at 36 months only, and serum blood and urine bone turnover markers (BTM) and blood bone biochemistry at enrolment, 6, 12, and 36 months. RESULTS: No statistically significant differences were found between the three groups for DXA outcome parameters, i.e., BMDa (L2-L4 BMDa g/cm2), bone mineral apparent density (L2-L4 BMAD g/cm3) and total body less head BMDa (TBLH g/cm2). All blood biochemistry markers were within the reference ranges, and BTM showed active bone turnover with a trend for BTM to decrease with increasing age. CONCLUSIONS: Bone density was clinically normal, although the median z scores were below the population mean. BTM showed active bone turnover and blood biochemistry was within the reference ranges. There appeared to be no advantage to bone density, mass, or geometry from taking a macropeptide-based protein substitute as compared with L-AAs.


Assuntos
Absorciometria de Fóton , Aminoácidos/metabolismo , Densidade Óssea/genética , Densidade Óssea/fisiologia , Remodelação Óssea , Caseínas/metabolismo , Fragmentos de Peptídeos/metabolismo , Fenilcetonúrias/dietoterapia , Adolescente , Antropometria , Biomarcadores/sangue , Biomarcadores/urina , Criança , Pré-Escolar , Feminino , Humanos , Estudos Longitudinais , Masculino , Osteoporose , Fenilcetonúrias/sangue , Fenilcetonúrias/urina
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