RESUMO
Pyroglutamate (pE)-modified amyloid-ß (Aß) peptides play a crucial role in the development of Alzheimer's disease. pEAß3-42 can rapidly form oligomers that gradually elongate hydrophobic segments to form ß-sheet-rich amyloid intermediates, ultimately resulting in the formation of mature amyloid fibrils. pEAß3-42 can also catalyze the aggregation of Aß species and subsequently accelerate the formation of amyloid senile plaques. Considering the recent clinical success of the pEAß3-42-targeting antibody donanemab, molecules that strongly bind pEAß3-42 and prevent its aggregation and catalytic effect on Aßs may also provide potential therapeutic options for Alzheimer's disease. Here, we demonstrate that the natural antibiotic cyclopeptide tyrocidine A (TA) not only strongly inhibits the aggregation of Aß1-42 as previously reported, but also interacts with the hydrophobic C-terminus and middle domain of pEAß3-42 to maintain an unordered conformation, effectively impeding the formation of initial oligomers and subsequently halting the aggregation of pEAß3-42. Furthermore, TA can disrupt the "catalytic effect" of pEAß3-42 on amyloid aggregates, effectively suppressing Aß aggregation and ultimately preventing the pathological events induced by Aßs.
Assuntos
Peptídeos beta-Amiloides , Interações Hidrofóbicas e Hidrofílicas , Ácido Pirrolidonocarboxílico , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/química , Ácido Pirrolidonocarboxílico/química , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/farmacologia , Humanos , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos/efeitos dos fármacos , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/tratamento farmacológicoRESUMO
Freesia refracta (FR), a perennial flower of the Iris family (Iridaceae), is widely used in cosmetics despite limited scientific evidence of its skin benefits and chemical composition, particularly of FR callus extract (FCE). This study identified biologically active compounds in FCE and assessed their skin benefits, focusing on anti-aging. FR calli were cultured, extracted with water at 40 °C, and analyzed using Centrifugal Partition Chromatography (CPC), Nuclear Magnetic Resonance (NMR), and HCA, revealing key compounds, namely nicotinamide and pyroglutamic acid. FCE significantly increased collagen I production by 52% in normal and aged fibroblasts and enhanced fibroblast-collagen interaction by 37%. An in vivo study of 43 female volunteers demonstrated an 11.1% reduction in skin roughness and a 2.3-fold increase in collagen density after 28 days of cream application containing 3% FCE. Additionally, the preservation tests of cosmetics containing FCE confirmed their stability over 12 weeks. These results suggest that FCE offers substantial anti-aging benefits by enhancing collagen production and fibroblast-collagen interactions. These findings highlighted the potential of FCE in cosmetic applications, providing significant improvements in skin smoothness and overall appearance. This study fills a gap in the scientific literature regarding the skin benefits and chemical composition of FR callus extract, supporting its use in the development of effective cosmeceuticals.
Assuntos
Fibroblastos , Estresse Oxidativo , Extratos Vegetais , Envelhecimento da Pele , Pele , Envelhecimento da Pele/efeitos dos fármacos , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Humanos , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pele/metabolismo , Pele/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Adulto , Colágeno/metabolismo , Cosméticos/farmacologia , Pessoa de Meia-Idade , Niacinamida/farmacologia , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/farmacologia , Ácido Pirrolidonocarboxílico/metabolismoRESUMO
BACKGROUND: Pyroglutamic acidosis is a rare cause of high anion gap metabolic acidosis. Most cases of paracetamol related pyroglutamic acidosis are described in malnourished women and patients with kidney/liver failure, alcohol use or severe sepsis. In this report, we describe how pyroglutamic acidosis could be related to the use of chronic therapeutic paracetamol with only malnutrition as an associated risk factor. CASE PRESENTATION: We report a case of a 67-year-old male patient developing a pyroglutamic acidosis. The patient was initially admitted to hospital for infectious osteoarthritis and developed a metabolic acidosis during his hospital stay. Analgesics included daily therapeutic doses of paracetamol. What makes our case unusual is that our malnourished male patient did not have renal or hepatic failure. The diagnosis of paracetamol related pyroglutamic acidosis was made after ruling out the main causes of metabolic acidosis. It was further confirmed by urine organic acids measurement showing a markedly elevated level of pyroglutamic aciduria. Paracetamol was discontinued allowing a prompt correction of the anion gap. CONCLUSION: This case is a representative of pyroglutamic acidosis related to chronic therapeutic paracetamol with only malnutrition as an associated risk factor. Physicians should be aware of such unusual cause of metabolic acidosis, which may be more common than expected in hospitalized patients. A high clinical suspicion is needed when urine organic acids analysis is not available.
Assuntos
Acetaminofen , Acidose , Analgésicos não Narcóticos , Desnutrição , Humanos , Acetaminofen/efeitos adversos , Idoso , Masculino , Acidose/induzido quimicamente , Desnutrição/complicações , Analgésicos não Narcóticos/efeitos adversos , Ácido Pirrolidonocarboxílico , Equilíbrio Ácido-BaseRESUMO
Diaphorina citri serves as the primary vector for 'Candidatus Liberibacter asiaticus (CLas),' the bacterium associated with the severe Asian form of huanglongbing. CLas-positive D. citri are more fecund than their CLas-negative counterparts and require extra energy expenditure. Therefore, understanding the molecular mechanisms linking metabolism and reproduction is of particular importance. In this study, we found adipokinetic hormone (DcAKH) and its receptor (DcAKHR) were essential for increasing lipid metabolism and fecundity in response to CLas infection in D. citri. Knockdown of DcAKH and DcAKHR not only resulted in the accumulation of triacylglycerol and a decline of glycogen, but also significantly decreased fecundity and CLas titer in ovaries. Combined in vivo and in vitro experiments showed that miR-34 suppresses DcAKHR expression by binding to its 3' untranslated region, whilst overexpression of miR-34 resulted in a decline of DcAKHR expression and CLas titer in ovaries and caused defects that mimicked DcAKHR knockdown phenotypes. Additionally, knockdown of DcAKH and DcAKHR significantly reduced juvenile hormone (JH) titer and JH signaling pathway genes in fat bodies and ovaries, including the JH receptor, methoprene-tolerant (DcMet), and the transcription factor, Krüppel homolog 1 (DcKr-h1), that acts downstream of it, as well as the egg development related genes vitellogenin 1-like (DcVg-1-like), vitellogenin A1-like (DcVg-A1-like) and the vitellogenin receptor (DcVgR). As a result, CLas hijacks AKH/AKHR-miR-34-JH signaling to improve D. citri lipid metabolism and fecundity, while simultaneously increasing the replication of CLas, suggesting a mutualistic interaction between CLas and D. citri ovaries.
Assuntos
Fertilidade , Hemípteros , Hormônios de Inseto , Ácido Pirrolidonocarboxílico , Transdução de Sinais , Animais , Hormônios de Inseto/metabolismo , Hormônios de Inseto/genética , Feminino , Hemípteros/microbiologia , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Rhizobiaceae/fisiologia , Rhizobiaceae/metabolismo , Metabolismo dos Lipídeos , Ovário/microbiologia , Ovário/metabolismo , MicroRNAs/metabolismo , MicroRNAs/genética , Hormônios Juvenis/metabolismo , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Liberibacter , OligopeptídeosRESUMO
Glutathione (GSH) is an important antioxidant that is generated and degraded via the GSH cycle. Quantification of the main components in the GSH cycle is necessary to evaluate the process of GSH. In this study, a robust ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of 10 components (GSH; γ-glutamylcysteine; cysteinyl-glycine; n-acetylcysteine; homocysteine; cysteine; cystine; methionine; glutamate; pyroglutamic acid) in GSH cycle was developed. The approach was optimized in terms of derivative, chromatographic, and spectrometric conditions as well as sample preparation. The unstable thiol groups of GSH, γ-glutamylcysteine, cysteinyl-glycine, n-acetylcysteine, cysteine, and homocysteine were derivatized by n-ethylmaleimide. The derivatized and underivatized analytes were separated on an amino column with gradient elution. The method was further validated in terms of selectivity (no interference), linearity (R2 > 0.99), precision (% relative standard deviation [RSD%] range from 0.57 to 10.33), accuracy (% relative error [RE%] range from -3.42 to 10.92), stability (RSD% < 5.68, RE% range from -2.54 to 4.40), recovery (RSD% range from 1.87 to 7.87) and matrix effect (RSD% < 5.42). The validated method was applied to compare the components in the GSH cycle between normal and oxidative stress cells, which would be helpful in clarifying the effect of oxidative stress on the GSH cycle.
Assuntos
Glutationa , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Glutationa/análise , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Homocisteína/análise , Cisteína/análise , Ácido Pirrolidonocarboxílico/análise , Ácido Pirrolidonocarboxílico/química , Ácido Pirrolidonocarboxílico/metabolismo , Dipeptídeos/análise , Acetilcisteína/análise , Acetilcisteína/química , Cistina/análiseRESUMO
OBJECTIVE: It has been previously shown that brain-derived neurotrophic factor is linked with various types of cancer. Brain-derived neurotrophic factor is found to be highly expressed in multiple human cancers and associated with tumor growth, invasion, and metastasis. Adipokinetic hormones are functionally related to the vertebrate glucagon, as they have similar functionalities that manage the nutrient-dependent secretion of these two hormones. Migrasomes are new organelles that contain numerous small vesicles, which aid in transmitting signals between the migrating cells. Therefore, the aim of this study was to investigate the effects of Anax imperator adipokinetic hormone on brain-derived neurotrophic factor expression and ultrastructure of cells in the C6 glioma cell line. METHODS: The rat C6 glioma cells were treated with concentrations of 5 and 10 Anax imperator adipokinetic hormone for 24 h. The effects of the Anax imperator adipokinetic hormone on the migrasome formation and brain-derived neurotrophic factor expression were analyzed using immunocytochemistry and transmission electron microscope. RESULTS: The rat C6 glioma cells of the 5 and 10 µM Anax imperator adipokinetic hormone groups showed significantly high expressions of brain-derived neurotrophic factor and migrasomes numbers, compared with the control group. CONCLUSION: A positive correlation was found between the brain-derived neurotrophic factor expression level and the formation of migrasome, which indicates that the increased expression of brain-derived neurotrophic factor and the number of migrasomes may be involved to metastasis of the rat C6 glioma cell line induced by the Anax imperator adipokinetic hormone. Therefore, the expression of brain-derived neurotrophic factor and migrasome formation may be promising targets for preventing tumor proliferation, invasion, and metastasis in glioma.
Assuntos
Fator Neurotrófico Derivado do Encéfalo , Glioma , Oligopeptídeos , Ácido Pirrolidonocarboxílico , Glioma/metabolismo , Glioma/patologia , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Ratos , Linhagem Celular Tumoral , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Oligopeptídeos/farmacologia , Hormônios de Inseto/metabolismo , Movimento Celular/efeitos dos fármacos , Imuno-Histoquímica , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Organelas/metabolismo , Organelas/efeitos dos fármacos , Organelas/ultraestruturaRESUMO
Insects have about 50 neuropeptide genes and about 70 genes, coding for neuropeptide G protein-coupled receptors (GPCRs). An important, but small family of evolutionarily related insect neuropeptides consists of adipokinetic hormone (AKH), corazonin, and AKH/corazonin-related peptide (ACP). Normally, insects have one specific GPCR for each of these neuropeptides. The tick Ixodes scapularis is not an insect, but belongs to the subphylum Chelicerata, which comprises ticks, scorpions, mites, spiders, and horseshoe crabs. Many of the neuropeptides and neuropeptide GPCRs occurring in insects, also occur in chelicerates, illustrating that insects and chelicerates are evolutionarily closely related. The tick I. scapularis is an ectoparasite and health risk for humans, because it infects its human host with dangerous pathogens during a blood meal. Understanding the biology of ticks will help researchers to prevent tick-borne diseases. By annotating the I. scapularis genome sequence, we previously found that ticks contain as many as five genes, coding for presumed ACP receptors. In the current paper, we cloned these receptors and expressed each of them in Chinese Hamster Ovary (CHO) cells. Each expressed receptor was activated by nanomolar concentrations of ACP, demonstrating that all five receptors were functional ACP receptors. Phylogenetic tree analyses showed that the cloned tick ACP receptors were mostly related to insect ACP receptors and, next, to insect AKH receptors, suggesting that ACP receptor genes and AKH receptor genes originated by gene duplications from a common ancestor. Similar duplications have probably occurred for the ligand genes, during a process of ligand/receptor co-evolution. Interestingly, chelicerates, in contrast to all other arthropods, do not have AKH or AKH receptor genes. Therefore, the ancestor of chelicerates might have lost AKH and AKH receptor genes and functionally replaced them by ACP and ACP receptor genes. For the small family of AKH, ACP, and corazonin receptors and their ligands, gene losses and gene gains occur frequently between the various ecdysozoan clades. Tardigrades, for example, which are well known for their survival in extreme environments, have as many as ten corazonin receptor genes and six corazonin peptide genes, while insects only have one of each, or none.
Assuntos
Hormônios de Inseto , Ixodes , Neuropeptídeos , Oligopeptídeos , Ácido Pirrolidonocarboxílico , Receptores Acoplados a Proteínas G , Animais , Neuropeptídeos/metabolismo , Neuropeptídeos/genética , Hormônios de Inseto/metabolismo , Hormônios de Inseto/genética , Ixodes/metabolismo , Ixodes/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Oligopeptídeos/metabolismo , Oligopeptídeos/genética , Oligopeptídeos/química , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Filogenia , Sequência de Aminoácidos , Cricetulus , Células CHO , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Receptores de Neuropeptídeos/metabolismo , Receptores de Neuropeptídeos/genéticaRESUMO
Hungry animals need compensatory mechanisms to maintain flexible brain function, while modulation reconfigures circuits to prioritize resource seeking. In Drosophila, hunger inhibits aversively reinforcing dopaminergic neurons (DANs) to permit the expression of food-seeking memories. Multitasking the reinforcement system for motivation potentially undermines aversive learning. We find that chronic hunger mildly enhances aversive learning and that satiated-baseline and hunger-enhanced learning require endocrine adipokinetic hormone (AKH) signaling. Circulating AKH influences aversive learning via its receptor in four neurons in the ventral brain, two of which are octopaminergic. Connectomics revealed AKH receptor-expressing neurons to be upstream of several classes of ascending neurons, many of which are presynaptic to aversively reinforcing DANs. Octopaminergic modulation of and output from at least one of these ascending pathways is required for shock- and bitter-taste-reinforced aversive learning. We propose that coordinated enhancement of input compensates for hunger-directed inhibition of aversive DANs to preserve reinforcement when required.
Assuntos
Aprendizagem da Esquiva , Neurônios Dopaminérgicos , Proteínas de Drosophila , Fome , Hormônios de Inseto , Reforço Psicológico , Animais , Neurônios Dopaminérgicos/fisiologia , Neurônios Dopaminérgicos/metabolismo , Fome/fisiologia , Aprendizagem da Esquiva/fisiologia , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Hormônios de Inseto/metabolismo , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Oligopeptídeos , Drosophila melanogaster , Drosophila , Octopamina/metabolismo , Dopamina/metabolismo , Encéfalo/fisiologia , Encéfalo/metabolismoRESUMO
This case describes a rare occurrence of high anion gap metabolic acidosis due to chronic acetaminophen (paracetamol) usage, which can be confirmed by measuring 5-oxoproline (pyroglutamate), an organic acid metabolite. As acetaminophen is an extremely common drug prescribed in both inpatient and outpatient settings, a high degree of clinical suspicion is required to isolate it as the aetiology for metabolic acidosis. Management includes discontinuation of acetaminophen use and at times the supplementation of oral bicarbonate. Metabolic acidosis due to a high anion gap is commonly described by the mnemonic 'MUDPILES' in daily practice. A newer mnemonic, 'GOLD MARK' is proposed to be a more inclusive tool to assist in determining the cause of high anion gap metabolic acidosis, especially with such cases being reported.
Assuntos
Acetaminofen , Acidose , Analgésicos não Narcóticos , Feminino , Humanos , Masculino , Acetaminofen/efeitos adversos , Equilíbrio Ácido-Base/efeitos dos fármacos , Acidose/induzido quimicamente , Analgésicos não Narcóticos/efeitos adversos , Ácido PirrolidonocarboxílicoRESUMO
Diverse chemical and pharmacological strategies are currently being explored to minimize the unwanted side effects of currently used opioid analgesics while achieving effective pain relief. The use of multitarget ligands with activity at more than one receptor represents a promising therapeutic approach. We recently reported a bifunctional peptide-based hybrid LENART01 combining dermorphin and ranatensin pharmacophores, which displays activity to the mu-opioid receptor (MOR) and dopamine D2 receptor (D2R) in rat brains and spinal cords. In this study, we investigated the in vitro binding and functional activities to the human MOR and the in vivo pharmacology of LENART01 in mice after subcutaneous administration. In vitro binding assays showed LENART01 to bind and be selective to the human MOR over the other opioid receptor subtypes and delta, kappa and nociceptin receptors. In the [35S]GTPγS binding assay, LENART01 acted as a potent and full agonist to the human MOR. In mice, LENART01 produced dose-dependent antinociceptive effects in formalin-induced inflammatory pain, with increased potency than morphine. Antinociceptive effects were reversed by naloxone, indicating MOR activation in vivo. Behavioral studies also demonstrated LENART01's properties to induce less adverse effects without locomotor dysfunction and withdrawal syndrome compared to conventional opioid analgesics, such as morphine. LENART01 is the first peptide-based MOR-D2R ligand known to date and the first dual MOR-dopamine D2R ligand for which in vivo pharmacology is reported with antinociceptive efficacy and reduced opioid-related side effects. Our current findings may pave the way to new pain therapeutics with limited side effects in acute and chronic use.
Assuntos
Analgésicos Opioides , Oligopeptídeos , Ácido Pirrolidonocarboxílico/análogos & derivados , Receptores Opioides , Humanos , Ratos , Animais , Camundongos , Analgésicos Opioides/farmacologia , Ligantes , Morfina , Peptídeos Opioides/farmacologia , Dor/tratamento farmacológicoRESUMO
This review concerns the rare, acquired, usually iatrogenic, high-anion-gap metabolic acidosis, pyroglutamic acidosis. Pyroglutamate is a derivative of the amino acid glutamate, and is an intermediate in the 'glutathione cycle', by which glutathione is continuously synthesized and broken down. The vast majority of pyroglutamic acidosis cases occur in patients on regular, therapeutic doses of paracetamol. In about a third of cases, flucloxacillin is co-prescribed. In addition, the patients are almost always seriously unwell in other ways, typically with under-nourishment of some form. Paracetamol, with underlying disorders, conspires to divert the glutathione cycle, leading to the overproduction of pyroglutamate. Hypokalaemia is seen in about a third of cases. Once the diagnosis is suspected, it is simple to stop the paracetamol and change the antibiotic (if flucloxacillin is present), pending biochemistry. N-acetyl-cysteine can be given, but while the biochemical justification is compelling, the clinical evidence base is anecdotal.
Assuntos
Acetaminofen , Acidose , Ácido Pirrolidonocarboxílico , Humanos , Acetaminofen/efeitos adversos , Acidose/diagnóstico , Acidose/induzido quimicamente , Floxacilina/efeitos adversos , Floxacilina/uso terapêutico , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêuticoRESUMO
BACKGROUND: The ladybeetle, Coccinella septempunctata, an important predator, is widely used to control aphids, whiteflies, mites, thrips, and lepidopteran pests. Diapause control technology is key to extending C. septempunctata shelf-life and commercialization. Lipid accumulation is a major feature of reproductive diapause, but the function of AKH signaling as a regulator of lipid mobilization in reproductive diapause remains unclear. This study aimed to identify and characterize AKH and AKHR genes, and clarify their functions in reproductive diapause. RESULTS: The relative expression levels of CsAKH and CsAKHR were the highest in the head and fat body, respectively, and were significantly decreased under diapause conditions, both in developmental stages and tissues (head, midgut, fat body, and ovary). Furthermore, CsAKH and CsAKHR expression was increased significantly after juvenile hormone (JH) injection, but CsMet silencing significantly inhibited CsAKH and CsAKHR expression, whereas CsMet knockdown blocked the induction effect of JH. CsAKH and CsAKHR knockdown significantly reduced water content, increased lipid storage, and promoted the expression of genes related to lipid synthesis, but significantly blocked ovarian development, and induced forkhead box O (FOXO) gene expression in C. septempunctata under reproduction conditions. By contrast, injection of AKH peptide significantly inhibited FOXO expression, reduced lipid storage, and increased water content in C. septempunctata under diapause conditions. CONCLUSION: These results indicate that CsAKH and CsAKHR are involved in the regulation of lipid accumulation and ovarian development during diapause in C. septempunctata, and provide a promising target for manipulating C. septempunctata diapause. © 2024 Society of Chemical Industry.
Assuntos
Besouros , Diapausa de Inseto , Hormônios de Inseto , Proteínas de Insetos , Oligopeptídeos , Ácido Pirrolidonocarboxílico , Reprodução , Transdução de Sinais , Animais , Hormônios de Inseto/metabolismo , Hormônios de Inseto/genética , Besouros/fisiologia , Besouros/metabolismo , Besouros/crescimento & desenvolvimento , Besouros/genética , Ácido Pirrolidonocarboxílico/análogos & derivados , Ácido Pirrolidonocarboxílico/metabolismo , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Oligopeptídeos/metabolismo , Feminino , Metabolismo dos LipídeosRESUMO
Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by the formation of extracellular amyloid-ß (Aß) plaques. The underlying cause of AD is unknown, however, post-translational modifications (PTMs) of Aß have been found in AD patients and are thought to play a role in protein aggregation. One such PTM is pyroglutamylation, which can occur at two sites in Aß, Glu3 and Glu11. This modification of Aß involves the truncation and charge-neutralization of N-terminal glutamate, causing Aß to become more hydrophobic and prone to aggregation. The molecular mechanism by which the introduction of pyroglutamate (pE) promotes aggregation has not been determined. To gain a greater understanding of the role that charge neutralization and truncation of the N-terminus plays on Aß conformational sampling, we used the Drude polarizable force field (FF) to perform molecular dynamics simulations on AßpE3-42 and AßpE11-42 and comparing their properties to previous simulations of Aß1-42. The Drude polarizable FF allows for a more accurate representation of electrostatic interactions, therefore providing novel insights into the role that charge plays in protein dynamics. Here, we report the parametrization of pE in the Drude polarizable FF and the effect of pyroglutamylation on Aß. We found that AßpE3-42 and AßpE11-42 alter the permanent and induced dipoles of the peptide. Specifically, we found that AßpE3-42 and AßpE11-42 have modification-specific backbone and sidechain polarization response and perturbed solvation properties that shift the Aß conformational ensemble.
Assuntos
Peptídeos beta-Amiloides , Simulação de Dinâmica Molecular , Processamento de Proteína Pós-Traducional , Ácido Pirrolidonocarboxílico , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Humanos , Ácido Pirrolidonocarboxílico/química , Ácido Pirrolidonocarboxílico/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Doença de Alzheimer/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Conformação Proteica , Eletricidade EstáticaRESUMO
Neuropeptides are the main regulators of physiological, developmental, and behavioural processes in insects. Three insect neuropeptide systems, the adipokinetic hormone (AKH), corazonin (Crz), and adipokinetic hormone/corazonin-related peptide (ACP), and their cognate receptors, are related to the vertebrate gonadotropin (GnRH) system and form the GnRH superfamily of peptides. In the current study, the two signalling systems, AKH and ACP, of the yellow fever mosquito, Aedes aegypti, were comparatively investigated with respect to ligand binding to their respective receptors. To achieve this, the solution structure of the hormones was determined by nuclear magnetic resonance distance restraint methodology. Atomic-scale models of the two G protein-coupled receptors were constructed with the help of homology modelling. Thereafter, the binding sites of the receptors were identified by blind docking of the ligands to the receptors, and models were derived for each hormone system showing how the ligands are bound to their receptors. Lastly, the two models were validated by comparing the computational results with experimentally derived data available from the literature. This mostly resulted in an acceptable agreement, proving the models to be largely correct and usable. The identification of an antagonist versus a true agonist may, however, require additional testing. The computational data also explains the exclusivity of the two systems that bind only the cognate ligand. This study forms the basis for further drug discovery studies.
Assuntos
Aedes , Hormônios de Inseto , Neuropeptídeos , Oligopeptídeos , Ácido Pirrolidonocarboxílico/análogos & derivados , Febre Amarela , Animais , Ligantes , Modelos Químicos , Filogenia , Evolução Molecular , Neuropeptídeos/metabolismo , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismoRESUMO
Thyrotropin-releasing hormone (TRH) acts centrally to exert pleiotropic actions independently from its endocrine function, including antinociceptive effects against somatic pain in rodents. Whether exogenous or endogenous activation of TRH signaling in the brain modulates visceral pain is unknown. Adult male Sprague-Dawley rats received an intracerebroventricular (ICV) injection of the stable TRH analog, RX-77368 (10, 30 and 100â¯ng/rat) or saline (5⯵l) or were semi-restrained and exposed to cold (4°C) for 45â¯min. The visceromotor response (VMR) to graded phasic colorectal distensions (CRD) was monitored using non-invasive intracolonic pressure manometry. Naloxone (1â¯mg/kg) was injected subcutaneously 10â¯min before ICV RX-77368 or saline. Fecal pellet output was monitored for 1â¯h after ICV injection. RX-77368 ICV (10, 30 and 100â¯ng/rat) reduced significantly the VMR by 56.7%, 67.1% and 81.1% at 40â¯mmHg and by 30.3%, 58.9% and 87.4% at 60â¯mmHg respectively vs ICV saline. Naloxone reduced RX-77368 (30 and 100â¯ng, ICV) analgesic response by 51% and 28% at 40â¯mmHg and by 30% and 33% at 60â¯mmHg respectively, but had no effect per se. The visceral analgesia was mimicked by the acute exposure to cold. At the doses of 30 and 100â¯ng, ICV RX-77368 induced defecation within 30â¯min. These data established the antinociceptive action of RX-77368 injected ICV in a model of visceral pain induced by colonic distension through recruitment of both opioid and non-opioid dependent mechanisms.
Assuntos
Neoplasias Colorretais , Ácido Pirrolidonocarboxílico/análogos & derivados , Hormônio Liberador de Tireotropina/análogos & derivados , Dor Visceral , Ratos , Masculino , Animais , Ratos Sprague-Dawley , Dor Visceral/tratamento farmacológico , Analgésicos/farmacologia , Naloxona/farmacologiaRESUMO
Since its discovery in 1958 in the lens of cows, ophthalmic acid (OPH) has stood in the shadow of its anti-oxidant analog: glutathione (GSH). Lacking the thiol group that gives GSH many of its important properties, ophthalmic acid's function has remained elusive, and it has been widely presumed to be an accidental product of the same enzymes. In this review, we compile evidence demonstrating that OPH is a ubiquitous metabolite found in bacteria, plants, fungi, and animals, produced through several layers of metabolic regulation. We discuss the limitations of the oft-repeated suggestions that aberrations in OPH levels should solely indicate GSH deficiency or oxidative stress. Finally, we discuss the available literature and suggest OPH's role in metabolism as a GSH-regulating tripeptide; controlling both cellular and organelle influx and efflux of GSH, as well as modulating GSH-dependent reactions and signaling. Ultimately, we hope that this review reinvigorates and directs more research into this versatile metabolite.
Assuntos
Glutationa , Glutationa/metabolismo , Animais , Humanos , Ácido Pirrolidonocarboxílico/metabolismo , Ácido Pirrolidonocarboxílico/análogos & derivados , Estresse Oxidativo , Oligopeptídeos/metabolismoRESUMO
Gonadotropin-releasing hormone (GnRH) superfamily comprises multiple families of signaling peptides in both protostomes and deuterostomes. Among this superfamily, vertebrate GnRH stimulates reproduction, but other GnRH superfamily members elicit diverse pleiotropic effects. Within the GnRH superfamily members, adipokinetic hormone (AKH) and its receptor are well described in ecdysozoans but understudied in other lineages. To fill this knowledge gap, we deorphanized a putative receptor for a lophotrochozoan AKH in a gastropod mollusk, Aplysia californica, and named it Aplca-AKHR. Phylogenetic analysis revealed an orthologous relationship of Aplca-AKHR with ecdysozoan AKHRs and other putative lophotrochozoan AKHRs. Aplca-AKHR bound specifically to the previously identified Aplca-AKH with high affinity and activated the inositol phosphate pathway. Aplca-AKHR was expressed widely among central and peripheral tissues, but most prominently in several central ganglia and the heart. The expression of Aplca-AKHR was downregulated by a hyposaline challenge, consistent with a role in volume and fluid regulation previously described for its ligand, Aplca-AKH. In summary, this is the first pairing of a lophotrochozoan AKH with its cognate receptor. Expression data further support diverse central and peripheral roles, including volume and fluid control, of this ligand/receptor pair.
Assuntos
Gastrópodes , Hormônios de Inseto , Animais , Aplysia/genética , Aplysia/metabolismo , Sequência de Aminoácidos , Gastrópodes/metabolismo , Filogenia , Ligantes , Hormônio Liberador de Gonadotropina/metabolismo , Hormônios de Inseto/metabolismo , Ácido Pirrolidonocarboxílico/metabolismoRESUMO
Extracellular amyloid-ß (Aß) plaques, primarily formed by Aß(1-40) and Aß(1-42) fibrils, are a hallmark of Alzheimer's disease. The Aß peptide can undergo a high variety of different post-translational modifications including formation of a pyroglutamate (pGlu, pE) at N-terminal Glu3 or Glu11 of truncated Aß(3-x) or Aß(11-x), respectively. Here we studied structural similarities and differences between pEAß(3-42) and LS-shaped Aß(1-42) fibrils grown under identical conditions (pHâ 2) using solid-state NMR spectroscopy. We show that the central region of pEAß(3-42) fibrils including the turn region around V24 is almost identical to Aß(1-42) showing similar ß-strands also at the N-terminus. The missing N-terminal residues D1-A2 along with pE3 formation in pEAß(3-42) preclude a salt bridge between K28-D1' as in Aß(1-42) fibrils. G37 and G38 act as highly sensitive internal sensors for the modified N-terminus, which remains rigid over ~five pH units.
Assuntos
Doença de Alzheimer , Ácido Pirrolidonocarboxílico , Humanos , Ácido Pirrolidonocarboxílico/química , Peptídeos beta-Amiloides/química , Espectroscopia de Ressonância Magnética , Fragmentos de Peptídeos/químicaRESUMO
Venous thromboembolism is a serious problem because it significantly increases the risk of developing vascular complications in elderly patients with obesity or immobilization, cancer, and many other diseases. Thus, there is a need to study new therapeutic strategies, including new medicinal agents for the efficient and safe correction of thrombus disorders. In this work, we have synthesized a number of new amides and peptides of 4-amino-5-oxoprolines and studied their antiplatelet and antithrombotic activity in experiments in vitro and in vivo. It has been found that the newly obtained compounds slow down the process of thrombus formation in a model of arterial and venous thrombosis, without affecting plasma hemostasis parameters. (2S,4S)-4-Amino-1-(4-fluorophenyl)-5-oxoprolyl-(S)-phenylalanine proved to be the most efficient among the studied derivatives. The results obtained indicate the advisability of further studies on 5-oxoproline derivatives in order to design pharmaceutical agents for the prevention and treatment of the consequences of thrombosis.
Assuntos
Ácido Pirrolidonocarboxílico , Trombose , Humanos , Idoso , Ácido Pirrolidonocarboxílico/química , Fibrinolíticos/farmacologia , Fibrinolíticos/uso terapêutico , Amidas/farmacologia , Trombose/tratamento farmacológico , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Inibidores da Agregação Plaquetária/químicaRESUMO
INTRODUCTION: Atherosclerosis, a precursor to cardiovascular disease (CVD), is deeply intertwined with lipid metabolism. The metabolic process in the Down syndrome (DS) population remain less explored. Aim of the study: This study examines the lipid profiles of DS in comparison to their siblings (CG), aiming to uncover potential atherosclerotic and CVD risks. MATERIAL AND METHODS: The study included 42 people with DS (mean age 14.17 years) and the CG - 20 individuals (mean age 15.92 years). Anthropometric measurements: BMI, BMI SDS, and TMI were calculated. Lipid profile (LP) and metabolomics were determined. RESULTS: LP: DS display significantly reduced HDL (DS vs. CG: 47±10 vs. 59 ±12 mg/dl; p = 0.0001) and elevated LDL (104 ±25 vs. 90 ±22 mg/dl; p = 0.0331). Triglycerides, APO A1, and APO B/APO A1 ratio corroborate with the elevated risk of CVD in DS. Despite no marked differences in: TCH and APO B, the DS group demonstrated a concerning BMI trend. Of 31 identified metabolites, 12 showed statistical significance (acetate, choline, creatinine, formate, glutamine, histidine, lysine, proline, pyroglutamate, threonine, tyrosine, and xanthine). However, only 8 metabolites passed the FDR validation (acetate, creatinine, formate, glutamine, lysine, proline, pyroglutamate, xanthine). CONCLUSIONS: Down syndrome individuals show distinct cardiovascular risks, with decreased HDL and increased LDL levels. Combined with metabolomic disparities and higher BMI and TMI, this suggests an increased atherosclerosis risk compared to controls.