RESUMEN
Chemerin is a processed protein that acts on G protein-coupled receptors (GPCRs) for its chemotactic and adipokine activities. The biologically active chemerin (chemerin 21-157) results from proteolytic cleavage of prochemerin and uses its C-terminal peptide containing the sequence YFPGQFAFS for receptor activation. Here we report a high-resolution cryo-electron microscopy (cryo-EM) structure of human chemerin receptor 1 (CMKLR1) bound to the C-terminal nonapeptide of chemokine (C9) in complex with Gi proteins. C9 inserts its C terminus into the binding pocket and is stabilized through hydrophobic interactions involving its Y1, F2, F6, and F8, as well as polar interactions between G4, S9, and several amino acids lining the binding pocket of CMKLR1. Microsecond scale molecular dynamics simulations support a balanced force distribution across the whole ligand-receptor interface that enhances thermodynamic stability of the captured binding pose of C9. The C9 interaction with CMKLR1 is drastically different from chemokine recognition by chemokine receptors, which follow a two-site two-step model. In contrast, C9 takes an "S"-shaped pose in the binding pocket of CMKLR1 much like angiotensin II in the AT1 receptor. Our mutagenesis and functional analyses confirmed the cryo-EM structure and key residues in the binding pocket for these interactions. Our findings provide a structural basis for chemerin recognition by CMKLR1 for the established chemotactic and adipokine activities.
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Adipoquinas , Quimiocinas , Receptores de Quimiocina , Humanos , Membrana Celular , Quimiocinas/metabolismo , Microscopía por Crioelectrón , Receptores de Quimiocina/metabolismoRESUMEN
G protein-coupled chemoattractant receptors are class A GPCRs that couple primarily to the Gi class of heterotrimeric G proteins. Initially identified for their abilities to mediate leukocyte chemotaxis, chemoattractant GPCRs such as the formyl peptide receptors (FPRs) have been known for their diverse cellular functions in response to a variety of agonists. Stimulation of FPR2, in particular, leads to ligand-dependent activation of proinflammatory signaling as well as anti-inflammatory and proresolving signaling. Recently, the structures of FPR2-Gi protein complexed with ligands of different compositions have been solved by crystallization and cryo-electron microscopy. Analysis of the structural data as well as molecular simulation has led to the findings that the FPR2 binding pocket is sufficiently large for accommodation of several different types of ligands but in different poses. This mini-review focuses on the structural and conformational aspects of FPR2 for mechanisms underlying its biased agonism.
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Receptores de Formil Péptido , Receptores de Lipoxina , Factores Quimiotácticos , Microscopía por Crioelectrón , Ligandos , Receptores de Formil Péptido/agonistas , Receptores de Formil Péptido/metabolismo , Receptores de Lipoxina/agonistas , Receptores de Lipoxina/metabolismoRESUMEN
G protein-coupled receptors (GPCRs) play important roles in human physiology. GPCRs are involved in immunoregulation including regulation of the inflammatory response. Chemotaxis of phagocytes and lymphocytes is mediated to a great extent by the GPCRs for chemoattractants including myriads of chemokines. Accumulation and activation of phagocytes at the site of inflammation contribute to local inflammatory response. A handful of GPCRs have been found to transduce anti-inflammatory signals that promote resolution of inflammation. These GPCRs interact with selected metabolites of arachdonic acid, such as lipoxins, and of omega-3 essential fatty acids, such as resolvins and protectins. Despite mounting evidence for the in vivo functions of these anti-inflammatory and pro-resolving ligands paired with their respective GPCRs, the underlying signaling mechanisms have not been fully delineated. The present review summarizes what we have learned about these GPCRs, their structures and signaling pathways and the prospect of targeting these receptors for novel anti-inflammatory therapies.
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Inmunomodulación/fisiología , Receptores Acoplados a Proteínas G/metabolismo , Transducción de Señal/fisiología , Humanos , Lipoxinas/metabolismo , Simulación del Acoplamiento Molecular , Receptores de Formil Péptido/metabolismo , Receptores de Lipoxina/metabolismoRESUMEN
We previously reported a novel toxic peptide identified from the anthozoan Protopalythoa variabilis transcriptome which is homologous to a novel structural type of sodium channel toxin isolated from a parental species (Palythoa caribaeorum). The peptide was named, according to its homologous, as Pp V-shape α-helical peptide (PpVα) in the present study. Through molecular docking and dynamics simulation, linear and hairpin folded PpVα peptides were shown to be potential voltage-gated sodium channel blockers. Nowadays, sodium channel blockers have been the mainstream of the pharmacological management of epileptic seizures. Also, sodium channel blockers could promote neuronal survival by reducing sodium influx and reducing the likelihood of calcium importation resulting in suppressing microglial activation and protecting dopaminergic neurons from degeneration. The folded PpVα peptide could decrease pentylenetetrazol (PTZ)-induced c-fos and npas4a expression level leading to reverse PTZ-induced locomotor hyperactivity in zebrafish model. In vitro, the folded PpVα peptide protected PC12 cells against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity via activating heme oxygenase-1 (HO-1) and attenuating inducible nitric oxide synthase (iNOS) expression. In vivo, PpVα peptide suppressed the 6-OHDA-induced neurotoxicity on the locomotive behavior of zebrafish and, importantly, prevented the 6-OHDA-induced excessive ROS generation and subsequent dopaminergic neurons loss. This study indicates that the single S-S bond folded PpVα peptide arises as a new structural template to develop sodium channel blockers and provides an insight on the peptide discovery from cnidarian transcriptome to potentially manage epilepsy and neurodegenerative disorders.
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Antozoos/química , Anticonvulsivantes/farmacología , Fármacos Neuroprotectores/farmacología , Péptidos/farmacología , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Canales de Sodio Activados por Voltaje/metabolismo , Secuencia de Aminoácidos , Animales , Hemo Oxigenasa (Desciclizante)/metabolismo , Locomoción , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Óxido Nítrico Sintasa de Tipo II/metabolismo , Oxidopamina/efectos adversos , Células PC12 , Pentilenotetrazol/efectos adversos , Péptidos/síntesis química , Estructura Terciaria de Proteína , Ratas , Especies Reactivas de Oxígeno/metabolismo , Pez CebraRESUMEN
Venoms from marine animals have been recognized as a new emerging source of peptide-based therapeutics. Several peptide toxins from sea anemone have been investigated as therapeutic leads or pharmacological tools. Venom complexity should be further highlighted using combined strategies of large-scale sequencing and data analysis which integrated transcriptomics and proteomics to elucidate new proteins or peptides to be compared among species. In this work, transcriptomic and proteomic analyses were combined to identify six groups of expressed peptide toxins in Zoanthus natalensis. These include neurotoxin, hemostatic and hemorrhagic toxin, protease inhibitor, mixed function enzymes, venom auxiliary proteins, allergen peptides, and peptides related to the innate immunity. Molecular docking analysis indicated that one expressed Zoanthus Kunitz-like peptide, ZoaKuz1, could be a voltage-gated potassium channels blocker and, hence, it was selected for functional studies. Functional bioassays revealed that ZoaKuz1 has an intrinsic neuroprotective activity in zebrafish model of Parkinson's disease. Since pharmacological blockade of KV channels is known to induce neuroprotective effects, ZoaKuz1 holds the potential to be developed in a therapeutic tool to control neural dysfunction by slowing or even halting neurodegeneration mediated by ion-channel hyperactivity.
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Venenos de Cnidarios/genética , Venenos de Cnidarios/toxicidad , Péptidos/genética , Péptidos/toxicidad , Proteómica , Anémonas de Mar/genética , Transcriptoma , Alérgenos/genética , Alérgenos/toxicidad , Animales , Antiparkinsonianos/farmacología , Hemostáticos , Humanos , Simulación del Acoplamiento Molecular , Fármacos Neuroprotectores/farmacología , Neurotoxinas/genética , Neurotoxinas/toxicidad , Bloqueadores de los Canales de Potasio/farmacología , Inhibidores de Proteasas/farmacología , Pliegue de Proteína , Pez CebraRESUMEN
Palythoa caribaeorum (class Anthozoa) is a zoanthid that together jellyfishes, hydra, and sea anemones, which are venomous and predatory, belongs to the Phyllum Cnidaria. The distinguished feature in these marine animals is the cnidocytes in the body tissues, responsible for toxin production and injection that are used majorly for prey capture and defense. With exception for other anthozoans, the toxin cocktails of zoanthids have been scarcely studied and are poorly known. Here, on the basis of the analysis of P. caribaeorum transcriptome, numerous predicted venom-featured polypeptides were identified including allergens, neurotoxins, membrane-active, and Kunitz-like peptides (PcKuz). The three predicted PcKuz isotoxins (1-3) were selected for functional studies. Through computational processing comprising structural phylogenetic analysis, molecular docking, and dynamics simulation, PcKuz3 was shown to be a potential voltage gated potassium-channel inhibitor. PcKuz3 fitted well as new functional Kunitz-type toxins with strong antilocomotor activity as in vivo assessed in zebrafish larvae, with weak inhibitory effect toward proteases, as evaluated in vitro. Notably, PcKuz3 can suppress, at low concentration, the 6-OHDA-induced neurotoxicity on the locomotive behavior of zebrafish, which indicated PcKuz3 may have a neuroprotective effect. Taken together, PcKuz3 figures as a novel neurotoxin structure, which differs from known homologous peptides expressed in sea anemone. Moreover, the novel PcKuz3 provides an insightful hint for biodrug development for prospective neurodegenerative disease treatment.
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Antozoos/química , Venenos de Cnidarios/aislamiento & purificación , Neurotoxinas/aislamiento & purificación , Péptidos/aislamiento & purificación , Bloqueadores de los Canales de Potasio/aislamiento & purificación , Transcriptoma , Alérgenos/química , Alérgenos/aislamiento & purificación , Animales , Antozoos/patogenicidad , Antozoos/fisiología , Sitios de Unión , Venenos de Cnidarios/química , Venenos de Cnidarios/toxicidad , Secuenciación de Nucleótidos de Alto Rendimiento , Larva/efectos de los fármacos , Larva/fisiología , Locomoción/efectos de los fármacos , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Neurotoxinas/química , Neurotoxinas/toxicidad , Oxidopamina/antagonistas & inhibidores , Oxidopamina/farmacología , Péptidos/química , Péptidos/toxicidad , Bloqueadores de los Canales de Potasio/química , Bloqueadores de los Canales de Potasio/toxicidad , Canales de Potasio con Entrada de Voltaje/antagonistas & inhibidores , Canales de Potasio con Entrada de Voltaje/química , Canales de Potasio con Entrada de Voltaje/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Pez CebraRESUMEN
Marine invertebrates, such as sponges, tunicates and cnidarians (zoantharians and scleractinian corals), form functional assemblages, known as holobionts, with numerous microbes. This type of species-specific symbiotic association can be a repository of myriad valuable low molecular weight organic compounds, bioactive peptides and enzymes. The zoantharian Protopalythoa variabilis (Cnidaria: Anthozoa) is one such example of a marine holobiont that inhabits the coastal reefs of the tropical Atlantic coast and is an interesting source of secondary metabolites and biologically active polypeptides. In the present study, we analyzed the entire holo-transcriptome of P. variabilis, looking for enzyme precursors expressed in the zoantharian-microbiota assemblage that are potentially useful as industrial biocatalysts and biopharmaceuticals. In addition to hundreds of predicted enzymes that fit into the classes of hydrolases, oxidoreductases and transferases that were found, novel enzyme precursors with multiple activities in single structures and enzymes with incomplete Enzyme Commission numbers were revealed. Our results indicated the predictive expression of thirteen multifunctional enzymes and 694 enzyme sequences with partially characterized activities, distributed in 23 sub-subclasses. These predicted enzyme structures and activities can prospectively be harnessed for applications in diverse areas of industrial and pharmaceutical biotechnology.
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Antozoos/enzimología , Organismos Acuáticos/enzimología , Productos Biológicos , Enzimas/genética , Animales , Antozoos/genética , Organismos Acuáticos/genética , Biocatálisis , Biotecnología/métodos , Enzimas/metabolismo , Tecnología Química Verde/métodos , Industrias/métodos , TranscriptomaRESUMEN
BACKGROUND: The nuclear envelope is considered a key classification marker that distinguishes prokaryotes from eukaryotes. However, this marker does not apply to the family Planctomycetaceae, which has intracellular spaces divided by lipidic intracytoplasmic membranes (ICMs). Nuclear localization signal (NLS), a short stretch of amino acid sequence, destines to transport proteins from cytoplasm into nucleus, and is also associated with the development of nuclear envelope. We attempted to investigate the NLS motifs in Planctomycetaceae genomes to demonstrate the potential molecular transition in the development of intracellular membrane system. RESULTS: In this study, we identified NLS-like motifs that have the same amino acid compositions as experimentally identified NLSs in genomes of 11 representative species of family Planctomycetaceae. A total of 15 NLS types and 170 NLS-bearing proteins were detected in the 11 strains. To determine the molecular transformation, we compared NLS-bearing protein abundances in the 11 representative Planctomycetaceae genomes with them in genomes of 16 taxonomically varied microorganisms: nine bacteria, two archaea and five fungi. In the 27 strains, 29 NLS types and 1101 NLS-bearing proteins were identified, principal component analysis showed a significant transitional gradient from bacteria to Planctomycetaceae to fungi on their NLS-bearing protein abundance profiles. Then, we clustered the 993 non-redundant NLS-bearing proteins into 181 families and annotated their involved metabolic pathways. Afterwards, we aligned the ten types of NLS motifs from the 13 families containing NLS-bearing proteins among bacteria, Planctomycetaceae or fungi, considering their diversity, length and origin. A transition towards increased complexity from non-planctomycete bacteria to Planctomycetaceae to archaea and fungi was detected based on the complexity of the 10 types of NLS-like motifs in the 13 NLS-bearing proteins families. CONCLUSION: The results of this study reveal that Planctomycetaceae separates slightly from the members of non-planctomycete bacteria but still has substantial differences from fungi, based on the NLS-like motifs and NLS-bearing protein analysis.
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Evolución Biológica , Señales de Localización Nuclear/genética , Señales de Localización Nuclear/metabolismo , Planctomycetales/genética , Planctomycetales/metabolismo , Secuencia de Aminoácidos , Archaea , Proteínas Portadoras/genética , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteínas Fúngicas , Redes y Vías Metabólicas , Señales de Localización Nuclear/clasificación , Señales de Localización Nuclear/aislamiento & purificación , Proteínas Nucleares/genética , Filogenia , Planctomycetales/clasificación , Transporte de ProteínasRESUMEN
Aging is a process that represents the accumulation of changes in organism overtime. In biological level, accumulations of molecular and cellular damage in aging lead to an increasing risk of diseases like sarcopenia. Sarcopenia reduces mobility, leads to fall-related injuries, and diminishes life quality. Thus, it is meaningful to find out novel therapeutic strategies for sarcopenia intervention that may help the elderly maintain their functional ability. Oxidative damage-induced dysfunctional mitochondria are considered as a culprit of muscle wasting during aging. Herein, we aimed to demonstrate whether myricanol (MY) protects aged mice against muscle wasting through alleviating oxidative damage in mitochondria and identify the direct protein target and its underlying mechanism. We discovered that MY protects aged mice against the loss of muscle mass and strength through scavenging reactive oxygen species accumulation to rebuild the redox homeostasis. Taking advantage of biophysical assays, peroxiredoxin 5 was discovered and validated as the direct target of MY. Through activating peroxiredoxin 5, MY reduced reactive oxygen species accumulation and damaged mitochondrial DNA in C2C12 myotubes. Our findings provide an insight for therapy against sarcopenia through alleviating oxidative damage-induced dysfunctional mitochondria by targeting peroxiredoxin 5, which may contribute an insight for healthy aging.
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CXCR4 binding of its endogenous agonist CXCL12 leads to diverse functions, including bone marrow retention of hematopoietic progenitors and cancer metastasis. However, the structure of the CXCL12-bound CXCR4 remains unresolved despite available structures of CXCR4 in complex with antagonists. Here, we present the cryoelectron microscopy (cryo-EM) structure of the CXCL12-CXCR4-Gi complex at an overall resolution of 2.65 Å. CXCL12 forms a 1:1 stoichiometry complex with CXCR4, following the two-site model. The first 8 amino acids of mature CXCL12 are crucial for CXCR4 activation by forming polar interactions with minor sub-pocket residues in the transmembrane binding pocket. The 3.2-Å distance between V3 of CXCL12 and the "toggle switch" W6.48 marks the deepest insertion among all chemokine-receptor pairs, leading to conformational changes of CXCR4 for G protein activation. These results, combined with functional assays and computational analysis, provide the structural basis for CXCR4 activation by CXCL12.
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Quimiocina CXCL12 , Microscopía por Crioelectrón , Unión Proteica , Receptores CXCR4 , Receptores CXCR4/metabolismo , Receptores CXCR4/química , Quimiocina CXCL12/metabolismo , Quimiocina CXCL12/química , Microscopía por Crioelectrón/métodos , Humanos , Modelos Moleculares , Sitios de Unión , Células HEK293RESUMEN
Parkinson's disease (PD) is the most common neurodegenerative movement disease. It is featured by abnormal alpha-synuclein (α-syn) aggregation in dopaminergic neurons in the substantia nigra. Macroautophagy (autophagy) is an evolutionarily conserved cellular process for degradation of cellular contents, including protein aggregates, to maintain cellular homeostasis. Corynoxine B (Cory B), a natural alkaloid isolated from Uncaria rhynchophylla (Miq.) Jacks., has been reported to promote the clearance of α-syn in cell models by inducing autophagy. However, the molecular mechanism by which Cory B induces autophagy is not known, and the α-syn-lowering activity of Cory B has not been verified in animal models. Here, we report that Cory B enhanced the activity of Beclin 1/VPS34 complex and increased autophagy by promoting the interaction between Beclin 1 and HMGB1/2. Depletion of HMGB1/2 impaired Cory B-induced autophagy. We showed for the first time that, similar to HMGB1, HMGB2 is also required for autophagy and depletion of HMGB2 decreased autophagy levels and phosphatidylinositol 3-kinase III activity both under basal and stimulated conditions. By applying cellular thermal shift assay, surface plasmon resonance, and molecular docking, we confirmed that Cory B directly binds to HMGB1/2 near the C106 site. Furthermore, in vivo studies with a wild-type α-syn transgenic drosophila model of PD and an A53T α-syn transgenic mouse model of PD, Cory B enhanced autophagy, promoted α-syn clearance and improved behavioral abnormalities. Taken together, the results of this study reveal that Cory B enhances phosphatidylinositol 3-kinase III activity/autophagy by binding to HMGB1/2 and that this enhancement is neuroprotective against PD.
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Efficient clearance of dying cells (efferocytosis) is an evolutionarily conserved process for tissue homeostasis. Genetic enhancement of efferocytosis exhibits therapeutic potential for inflammation resolution and tissue repair. However, pharmacological approaches to enhance efferocytosis remain sparse due to a lack of targets for modulation. Here, we report the identification of columbamine (COL) which enhances macrophage-mediated efferocytosis and attenuates intestinal inflammation in a murine colitis model. COL enhances efferocytosis by promoting LC3-associated phagocytosis (LAP), a non-canonical form of autophagy. Transcriptome analysis and pharmacological characterization revealed that COL is a biased agonist that occupies a part of the ligand binding pocket of formyl peptide receptor 2 (FPR2), a G-protein coupled receptor involved in inflammation regulation. Genetic ablation of the Fpr2 gene or treatment with an FPR2 antagonist abolishes COL-induced efferocytosis, anti-colitis activity and LAP. Taken together, our study identifies FPR2 as a potential target for modulating LC3-associated efferocytosis to alleviate intestinal inflammation and highlights the therapeutic value of COL, a natural and biased agonist of FPR2, in the treatment of inflammatory bowel disease.
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Colitis , Ratones , Animales , Fagocitosis , Transducción de Señal , Inflamación/genética , Macrófagos/metabolismo , Colitis/metabolismoRESUMEN
Metabolic flexibility is the ability to adapt to physiological and environmental changes in metabolic demand. Irisin was originally discovered as an exercise-induced myokine involved in fat browning. In this review, we summarize emerging evidence for the roles of irisin in regulating glucose metabolism and insulin sensitivity in skeletal muscle, neuroplasticity and satiety in central nervous system, ß cell function and insulin secretion in the pancreas, bone remodeling, and adipose tissue function, which together orchestrate whole-body metabolic flexibility. Irisin is a key communicating mediator between skeletal muscle and other organs, and its manipulation could be a promising therapeutic strategy for treating obesity and related metabolic disorders.
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Fibronectinas , Resistencia a la Insulina , Tejido Adiposo , Fibronectinas/metabolismo , Humanos , Músculo Esquelético/metabolismo , Obesidad/metabolismoRESUMEN
In type 2 diabetes mellitus (T2DM) and its related disorders like obesity, the abnormal protein processing, oxidative stress and proinflammatory cytokines will drive the activation of inflammatory pathways, leading to low-grade chronic inflammation and insulin resistance (IR) in the periphery and impaired neuronal insulin signaling in the brain. Studies have shown that such inflammation and impaired insulin signaling contribute to the development of Alzheimer's disease (AD). Therefore, new therapeutic strategies are needed for the treatment of T2DM and T2DM-linked AD. Melatonin is primarily known for its circadian role which conveys message of darkness and induces night-state physiological functions. Besides rhythm-related effects, melatonin has anti-inflammatory and antioxidant properties. Melatonin levels are downregulated in metabolic disorders with IR, and activation of melatonin signaling delays disease progression. The aim of this Review is to highlight the therapeutic potentials of melatonin in preventing the acceleration of AD in T2DM individuals through its therapeutic mechanisms, including antioxidative effects, anti-inflammatory effects, restoring mitochondrial function and insulin sensitivity.
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Enfermedad de Alzheimer , Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Melatonina , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Antiinflamatorios , Antioxidantes/uso terapéutico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Inflamación/tratamiento farmacológico , Insulina , Melatonina/metabolismo , Melatonina/uso terapéuticoRESUMEN
The formyl peptide receptor 1 (FPR1) is primarily responsible for detection of short peptides bearing N-formylated methionine (fMet) that are characteristic of protein synthesis in bacteria and mitochondria. As a result, FPR1 is critical to phagocyte migration and activation in bacterial infection, tissue injury and inflammation. How FPR1 distinguishes between formyl peptides and non-formyl peptides remains elusive. Here we report cryo-EM structures of human FPR1-Gi protein complex bound to S. aureus-derived peptide fMet-Ile-Phe-Leu (fMIFL) and E. coli-derived peptide fMet-Leu-Phe (fMLF). Both structures of FPR1 adopt an active conformation and exhibit a binding pocket containing the R2015.38XXXR2055.42 (RGIIR) motif for formyl group interaction and receptor activation. This motif works together with D1063.33 for hydrogen bond formation with the N-formyl group and with fMet, a model supported by MD simulation and functional assays of mutant receptors with key residues for recognition substituted by alanine. The cryo-EM model of agonist-bound FPR1 provides a structural basis for recognition of bacteria-derived chemotactic peptides with potential applications in developing FPR1-targeting agents.
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Moléculas de Patrón Molecular Asociado a Patógenos , Staphylococcus aureus , Factores Quimiotácticos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , N-Formilmetionina Leucil-Fenilalanina/química , Neutrófilos/metabolismo , Moléculas de Patrón Molecular Asociado a Patógenos/metabolismo , Péptidos/metabolismo , Staphylococcus aureus/metabolismoRESUMEN
PcActx peptide, identified from the transcriptome of zoantharian Palythoa caribaeorum, was clustered into the phylogeny of analgesic polypeptides from sea anemone Heteractis crispa (known as APHC peptides). APHC peptides were considered as inhibitors of transient receptor potential cation channel subfamily V member 1 (TRPV1). TRPV1 is a calcium-permeable channel expressed in epileptic brain areas, serving as a potential target for preventing epileptic seizures. Through in silico and in vitro analysis, PcActx peptide was shown to be a potential TRPV1 channel blocker. In vivo studies showed that the linear and oxidized PcActx peptides caused concentration-dependent increases in mortality of zebrafish larvae. However, monotreatment with PcActx peptides below the maximum tolerated doses (MTD) did not affect locomotor behavior. Moreover, PcActx peptides (both linear and oxidized forms) could effectively reverse pentylenetetrazol (PTZ)-induced seizure-related behavior in zebrafish larvae and prevent overexpression of c-fos and npas4a at the mRNA level. The excessive production of ROS induced by PTZ was markedly attenuated by both linear and oxidized PcActx peptides. It was also verified that the oxidized PcActx peptide was more effective than the linear one. In particular, oxidized PcActx peptide notably modulated the mRNA expression of genes involved in calcium signaling and γ-aminobutyric acid (GABA)ergic-glutamatergic signaling, including calb1, calb2, gabra1, grm1, gria1b, grin2b, gat1, slc1a2b, gad1b, and glsa. Taken together, PcActx peptide, as a novel neuroactive peptide, exhibits prominent anti-epileptic activity, probably through modulating calcium signaling and GABAergic-glutamatergic signaling, and is a promising candidate for epilepsy management.
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Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed.
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Antiinflamatorios/uso terapéutico , Fármacos Antiobesidad/uso terapéutico , Artemisininas/uso terapéutico , Sistema Inmunológico/efectos de los fármacos , Obesidad/tratamiento farmacológico , Animales , Antiinflamatorios/efectos adversos , Antiinflamatorios/química , Fármacos Antiobesidad/efectos adversos , Fármacos Antiobesidad/química , Artemisininas/efectos adversos , Artemisininas/química , Estrés del Retículo Endoplásmico/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Humanos , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Sistema Inmunológico/fisiopatología , Mediadores de Inflamación/metabolismo , Resistencia a la Insulina , Estructura Molecular , Obesidad/inmunología , Obesidad/metabolismo , Obesidad/fisiopatología , Transducción de Señal , Relación Estructura-ActividadRESUMEN
Cnidaria provide the largest source of bioactive peptides for new drug development. The venoms contain enzymes, potent pore-forming toxins and neurotoxins. The neurotoxins can immobilize predators rapidly when discharged via modifying sodium-channel-gating or blocking the potassium channel during the repolarization stage. Most cnidarian neurotoxins remain conserved under the strong influence of negative selection. Neuroactive peptides targeting the central nervous system through affinity with ion channels could provide insight leading to drug treatment of neurological diseases, which arise from ion channel dysfunctions. Although marine resources offer thousands of possible peptides, only one peptide derived from Cnidaria: ShK-186, also named dalazatide, has reached the pharmaceutical market. This review focuses on neuroprotective agents derived from cnidarian neurotoxic peptides.
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Enfermedades del Sistema Nervioso Central/tratamiento farmacológico , Cnidarios , Canales Iónicos/fisiología , Fármacos Neuroprotectores , Neurotoxinas , Péptidos , Animales , Descubrimiento de Drogas , Humanos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Neurotoxinas/farmacología , Neurotoxinas/uso terapéutico , Péptidos/farmacología , Péptidos/uso terapéutico , FilogeniaRESUMEN
BACKGROUND AND PURPOSE: Skeletal muscle is the predominant site for glucose disposal and fatty acid consumption. Emerging evidence indicates that the crosstalk between adipose tissue and skeletal muscle is critical in maintaining insulin sensitivity and lipid homeostasis. The current study was designed to investigate whether myricanol improves insulin sensitivity and alleviates adiposity through modulating skeletal muscle-adipose tissue crosstalk. EXPERIMENTAL APPROACH: The therapeutic effect of myricanol was evaluated on palmitic acid (PA)-treated C2C12 myotubes and high-fat diet (HFD)-fed mice. The crosstalk between myotubes and adipocytes was evaluated using Transwell assay. The cellular lipid content was examined by Nile red staining. The mitochondrial content was assessed by MitoTracker Green staining and citrate synthase activity, and the mitochondrial function was examined by Seahorse assay. Expression of mitochondria-related and insulin signalling pathway proteins was analysed by Western blot, and the irisin level was determined by elisa kit. KEY RESULTS: Myricanol increased mitochondrial quantity and function through activating AMP-activated protein kinase, resulting in reduced lipid accumulation and enhanced insulin-stimulated glucose uptake, in PA-treated C2C12 myotubes. Furthermore, myricanol stimulated irisin production and secretion from myotubes to reduce lipid content in 3T3-L1 adipocytes. In HFD-fed mice, myricanol treatment alleviated adiposity and insulin resistance through enhancing lipid utilization and irisin production in skeletal muscle and inducing browning of inguinal fat. CONCLUSIONS AND IMPLICATIONS: Myricanol modulates skeletal muscle-adipose tissue crosstalk, to stimulate browning of adipose tissue and improve insulin sensitivity in skeletal muscle. Myricanol might be a potential candidate for treating insulin resistance and obesity.
Asunto(s)
Tejido Adiposo/efectos de los fármacos , Diarilheptanoides/farmacología , Resistencia a la Insulina , Fibras Musculares Esqueléticas/efectos de los fármacos , Obesidad/tratamiento farmacológico , Células 3T3-L1 , Tejido Adiposo/metabolismo , Animales , Diferenciación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Dieta Alta en Grasa , Humanos , Ratones , Fibras Musculares Esqueléticas/metabolismo , Obesidad/inducido químicamente , Obesidad/metabolismoRESUMEN
BACKGROUND: Muscle atrophy and weakness are adverse effects of high dose or the sustained usage of glucocorticoids. Loss of mitochondria and degradation of protein are highly correlated with muscle dysfunction. The deacetylase sirtuin 1 (SIRT1) plays a vital role in muscle remodelling. The current study was designed to identify myricanol as a SIRT1 activator, which could protect skeletal muscle against dexamethasone-induced wasting. METHODS: The dexamethasone-induced atrophy in C2C12 myotubes was evaluated by expression of myosin heavy chain, muscle atrophy F-box (atrogin-1), and muscle ring finger 1 (MuRF1), using western blots. The mitochondrial content and oxygen consumption were assessed by MitoTracker staining and extracellular flux analysis, respectively. Muscle dysfunction was established in male C57BL/6 mice (8-10 weeks old, n = 6) treated with a relatively high dose of dexamethasone (25 mg/kg body weight, i.p., 10 days). Body weight, grip strength, forced swimming capacity, muscle weight, and muscle histology were assessed. The expression of proteolysis-related, autophagy-related, apoptosis-related, and mitochondria-related proteins was analysed by western blots or immunoprecipitation. RESULTS: Myricanol (10 µM) was found to rescue dexamethasone-induced muscle atrophy and dysfunction in C2C12 myotubes, indicated by increased expression of myosin heavy chain (0.33 ± 0.14 vs. 0.89 ± 0.21, *P < 0.05), decreased expression of atrogin-1 (2.31 ± 0.67 vs. 1.53 ± 0.25, *P < 0.05) and MuRF1 (1.55 ± 0.08 vs. 0.99 ± 0.12, **P < 0.01), and elevated ATP production (3.83 ± 0.46 vs. 5.84 ± 0.79 nM/mg protein, **P < 0.01), mitochondrial content (68.12 ± 10.07% vs. 116.38 ± 5.12%, *P < 0.05), and mitochondrial oxygen consumption (166.59 ± 22.89 vs. 223.77 ± 22.59 pmol/min, **P < 0.01). Myricanol directly binds and activates SIRT1, with binding energy of -5.87 kcal/mol. Through activating SIRT1 deacetylation, myricanol inhibits forkhead box O 3a transcriptional activity to reduce protein degradation, induces autophagy to enhance degraded protein clearance, and increases peroxisome proliferator-activated receptor γ coactivator-1α activity to promote mitochondrial biogenesis. In dexamethasone-induced muscle wasting C57BL/6 mice, 5 mg/kg myricanol treatment reduces the loss of muscle mass; the percentages of quadriceps and gastrocnemius muscle in myricanol-treated mice are 1.36 ± 0.02% and 0.87 ± 0.08%, respectively (cf. 1.18 ± 0.06% and 0.78 ± 0.05% in dexamethasone-treated mice, respectively). Myricanol also rescues dexamethasone-induced muscle weakness, indicated by improved grip strength (70.90 ± 4.59 vs. 120.58 ± 7.93 g, **P < 0.01) and prolonged swimming exhaustive time (48.80 ± 11.43 vs. 83.75 ± 15.19 s, **P < 0.01). Myricanol prevents dexamethasone-induced muscle atrophy and weakness by activating SIRT1, to reduce muscle protein degradation, enhance autophagy, and promote mitochondrial biogenesis and function in mice. CONCLUSIONS: Myricanol ameliorates dexamethasone-induced skeletal muscle wasting by activating SIRT1, which might be developed as a therapeutic agent for treatment of muscle atrophy and weakness.