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1.
Phys Chem Chem Phys ; 21(40): 22396-22408, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31577299

RESUMO

Our understanding of protein folds relies fundamentally on the set of secondary structures found in the proteomes. Yet, there also exist intriguing structures and motifs that are underrepresented in natural biopolymeric systems. One example is the polyproline II helix, which is usually considered to have a polar character and therefore does not form membrane spanning sections of membrane proteins. In our work, we have introduced specially designed polyproline II helices into the hydrophobic membrane milieu and used 19F NMR to monitor the helix alignment in oriented lipid bilayers. Our results show that these artificial hydrophobic peptides can adopt several different alignment states. If the helix is shorter than the thickness of the hydrophobic core of the membrane, it is submerged into the bilayer with its long axis parallel to the membrane plane. The polyproline helix adopts a transmembrane alignment when its length exceeds the bilayer thickness. If the peptide length roughly matches the lipid thickness, a coexistence of both states is observed. We thus show that the lipid thickness plays a determining role in the occurrence of a transmembrane polyproline II helix. We also found that the adaptation of polyproline II helices to hydrophobic mismatch is in some notable aspects different from α-helices. Finally, our results prove that the polyproline II helix is a competent structure for the construction of transmembrane peptide segments, despite the fact that no such motif has ever been reported in natural systems.


Assuntos
Bicamadas Lipídicas/metabolismo , Peptídeos/metabolismo , Flúor , Interações Hidrofóbicas e Hidrofílicas , Bicamadas Lipídicas/química , Espectroscopia de Ressonância Magnética , Peptídeos/síntese química , Peptídeos/química , Fosfatidilcolinas/química , Fosfatidilcolinas/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice
2.
Acta Virol ; 63(3): 278-285, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507193

RESUMO

Dengue virus (DENV) infection is one of the most widely-spread flavivirus infections with no effective antiviral drugs available. Peptide inhibitors have been considered as one of the best drug candidates due to their high specificity, selectivity in their interactions and minimum side effects. In this study, we employed computational studies using YASARA, HADDOCK server and PyMOL software to generate short and linear peptides based on a reference peptide, CP5-46A, to block DENV NS2B-NS3 protease. The inhibition potencies of the peptides were evaluated using in-house DENV2 serine protease and fluorogenic peptide substrates. In vitro analyses were performed to determine the peptides cytotoxicity and the inhibitory effects against DENV2 replication in WRL-68 cells. Our computational analyses revealed that the docking energy of AYA3, a 16 amino acid (aa) (-81.2 ± 10.6 kcal/mol) and AYA9, a 15 aa peptide (-83.8 ± 6.8 kcal/mol) to DENV NS2B-NS3 protease were much lower than the reference peptide (46 aa; -70.9 ± 7.8 kcal/mol) and the standard protease inhibitor, aprotinin (58 aa; -48.2 ± 10.6 kcal/mol). Both peptides showed significant inhibition against DENV2 NS2B-NS3 protease activity with IC50 values of 24 µM and 23 µM, respectively. AYA3 and AYA9 peptides also demonstrated approximately 68% and 83% of viral plaque reduction without significantly affecting cell viability at 50 µM concentration. In short, we generated short linear peptides with lower cytotoxic effect and substantial antiviral activities against DENV2. Further studies are required to investigate the inhibitory effects of these peptides in vivo. Keywords: peptide inhibitors; dengue virus; NS2B-NS3 protease; plaque reduction.


Assuntos
Antivirais , Vírus da Dengue , Peptídeos , Inibidores de Proteases , Replicação Viral , Antivirais/farmacologia , Biologia Computacional , Vírus da Dengue/enzimologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Peptídeos/síntese química , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia , Replicação Viral/efeitos dos fármacos
3.
J Cancer Res Clin Oncol ; 145(10): 2457-2468, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31463718

RESUMO

BACKGROUND: Our previous study identified a Wilms tumor-suppressing peptide (WTSP) that was upregulated in healthy children, but downregulated in children with Wilms tumor (WT). This study aimed to investigate the effect of WTSP on WT growth in vivo and in vitro. METHODS: WTSP was synthesized by solid-phase synthesis of FOMC-protected amino acids. Cell growth curve, cytotoxicity, and apoptosis of WTSP-treated human WT cell line (SK-NEP-1) were determined by cell count, Cell Counting Kit-8 assay, and flow cytometry. The expression of key proteins of four WT-associated signaling pathways was determined by real-time PCR and western blotting. The WT xenograft mouse model was established by the armpit injection of SK-NEP-1 cells. The TUNEL assay was used to detect apoptosis in mouse tumor cells. RESULTS: WTSP inhibited the proliferation of SK-NEP-1 cells in a dose- and time-dependent manner, and it arrested SK-NEP-1 cells in G2/M phase. WTSP-treated cells exhibited a low expression of PCNA and Bcl-2 and high expression of Bax. The expression of ß-catenin was markedly changed after WTSP treatment. WTSP-treated mice had significantly smaller tumors than untreated mice. CONCLUSION: Our findings indicated an anti-tumor effect of WTSP, which is correlated with Wnt/ß-catenin pathway. This newly identified peptide may exert a therapeutic effect of WT in the future.


Assuntos
Apoptose/efeitos dos fármacos , Peptídeos/farmacologia , Animais , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Camundongos , Peptídeos/síntese química , Peptídeos/química , Transdução de Sinais , Tumor de Wilms/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Chem Commun (Camb) ; 55(68): 10142-10145, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31389424

RESUMO

Hydrogen sulfide, an endogenous signalling molecule, is central to several pathophysiological processes in mammalian systems. It scavenges reactive oxygen species and is known to ameliorate dopaminergic neuronal degeneration in neurotoxin-induced Parkinson's disease models. The rapid volatilization of H2S from spontaneously releasing sulfide salts being a challenge, we describe peptide conjugates which exhibit tris(2-carboxyethyl)phosphine mediated "slow and sustained" H2S release. These conjugates reduced hydrogen peroxide-induced oxidative stress and significantly increased dopamine levels in transgenic C. elegans.


Assuntos
Dopamina/metabolismo , Sulfeto de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peptídeos/farmacologia , Tionas/farmacologia , Tiofenos/farmacologia , Animais , Animais Geneticamente Modificados , Anti-Inflamatórios/metabolismo , Antioxidantes/metabolismo , Caenorhabditis elegans/genética , Liberação Controlada de Fármacos , Oxirredução , Peptídeos/síntese química , Peptídeos/química , Fosfinas/química , Pró-Fármacos/síntese química , Pró-Fármacos/química , Pró-Fármacos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Tionas/síntese química , Tionas/química , Tiofenos/síntese química , Tiofenos/química , alfa-Sinucleína/genética
5.
Nature ; 571(7766): 546-549, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31292542

RESUMO

Amide bond formation is one of the most important reactions in both chemistry and biology1-4, but there is currently no chemical method of achieving α-peptide ligation in water that tolerates all of the 20 proteinogenic amino acids at the peptide ligation site. The universal genetic code establishes that the biological role of peptides predates life's last universal common ancestor and that peptides played an essential part in the origins of life5-9. The essential role of sulfur in the citric acid cycle, non-ribosomal peptide synthesis and polyketide biosynthesis point towards thioester-dependent peptide ligations preceding RNA-dependent protein synthesis during the evolution of life5,9-13. However, a robust mechanism for aminoacyl thioester formation has not been demonstrated13. Here we report a chemoselective, high-yielding α-aminonitrile ligation that exploits only prebiotically plausible molecules-hydrogen sulfide, thioacetate12,14 and ferricyanide12,14-17 or cyanoacetylene8,14-to yield α-peptides in water. The ligation is extremely selective for α-aminonitrile coupling and tolerates all of the 20 proteinogenic amino acid residues. Two essential features enable peptide ligation in water: the reactivity and pKaH of α-aminonitriles makes them compatible with ligation at neutral pH and N-acylation stabilizes the peptide product and activates the peptide precursor to (biomimetic) N-to-C peptide ligation. Our model unites prebiotic aminonitrile synthesis and biological α-peptides, suggesting that short N-acyl peptide nitriles were plausible substrates during early evolution.


Assuntos
Evolução Química , Nitrilos/química , Nitrilos/síntese química , Origem da Vida , Peptídeos/química , Peptídeos/síntese química , Água/química , Acetileno/análogos & derivados , Acetileno/química , Dipeptídeos/síntese química , Dipeptídeos/química , Ferricianetos/química , Sulfeto de Hidrogênio/química , Concentração de Íons de Hidrogênio , Oxirredução , Compostos de Sulfidrila/química , Sulfetos/química
6.
Chemistry ; 25(55): 12698-12702, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31361053

RESUMO

We report the late-stage chemical modification of ribosomally synthesized and post-translationally modified peptides (RIPPs) by Diels-Alder cycloadditions to naturally occurring dehydroalanines. The tail region of the thiopeptide thiostrepton could be modified selectively and efficiently under microwave heating and transition-metal-free conditions. The Diels-Alder adducts were isolated and the different site- and endo/exo isomers were identified by 1D/2D 1 H NMR. Via efficient modification of the thiopeptide nosiheptide and the lanthipeptide nisin Z the generality of the method was established. Minimum inhibitory concentration (MIC) assays of the purified thiostrepton Diels-Alder products against thiostrepton-susceptible strains displayed high activities comparable to that of native thiostrepton. These Diels-Alder products were also subjected successfully to inverse-electron-demand Diels-Alder reactions with a variety of functionalized tetrazines, demonstrating the utility of this method for labeling of RiPPs.


Assuntos
Alanina/análogos & derivados , Peptídeos/síntese química , Ribossomos/metabolismo , Alanina/síntese química , Alanina/química , Reação de Cicloadição , Peptídeos/química , Processamento de Proteína Pós-Traducional , Ribossomos/química
7.
Eur J Med Chem ; 180: 99-110, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31301567

RESUMO

Biologically active or bioactive peptides are unique amino acid sequences found encrypted in food proteins. These peptides, upon hydrolysis, can exert positive physiological effects on human health, different from that of their native protein. These effects are brought about by their interaction with specific targets in the body, thereby, mimicking physiologically relevant peptides. Peptides are derived from food proteins, they are popular natural alternatives for the management of common metabolic disorders. In the present study, we aimed to identify bioactive peptide sequences (less than 3 kDa) from fat globule membrane protein (FGMP) hydrolysates of buffalo colostrum using a combination of empirical, computational and in vitro methods. The empirical approach aided in the identification of 89 FGMP peptides (m/z-415 to 2939) which were annotated and profiled for bioactivity. Few lead peptides were analyzed by molecular docking for the inhibitory potential of Angiotensin Converting Enzyme (ACE) and Dipeptidyl Peptidase-IV (DPP-IV). A heptapeptide (m/z-723.3) synthesized was found to inhibit ACE (IC50: 74.27 µM) and DPP-IV (IC50: 3.83 mM).


Assuntos
Dipeptidil Peptidase 4/metabolismo , Descoberta de Drogas , Peptídeos/farmacologia , Peptidil Dipeptidase A/metabolismo , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Peptídeos/síntese química , Peptídeos/química , Relação Estrutura-Atividade
8.
Curr Top Med Chem ; 19(16): 1399-1417, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31284862

RESUMO

The pituitary adenylate cyclase-activating polypeptide (PACAP)-selective PAC1 receptor (PAC1R, ADCYAP1R1) is a member of the vasoactive intestinal peptide (VIP)/secretin/glucagon family of G protein-coupled receptors (GPCRs). PAC1R has been shown to play crucial roles in the central and peripheral nervous systems. The activation of PAC1R initiates diverse downstream signal transduction pathways, including adenylyl cyclase, phospholipase C, MEK/ERK, and Akt pathways that regulate a number of physiological systems to maintain functional homeostasis. Accordingly, at times of tissue injury or insult, PACAP/PAC1R activation of these pathways can be trophic to blunt or delay apoptotic events and enhance cell survival. Enhancing PAC1R signaling under these conditions has the potential to mitigate cellular damages associated with cerebrovascular trauma (including stroke), neurodegeneration (such as Parkinson's and Alzheimer's disease), or peripheral organ insults. Conversely, maladaptive PACAP/PAC1R signaling has been implicated in a number of disorders, including stressrelated psychopathologies (i.e., depression, posttraumatic stress disorder, and related abnormalities), chronic pain and migraine, and metabolic diseases; abrogating PAC1R signaling under these pathological conditions represent opportunities for therapeutic intervention. Given the diverse PAC1R-mediated biological activities, the receptor has emerged as a relevant pharmaceutical target. In this review, we first describe the current knowledge regarding the molecular structure, dynamics, and function of PAC1R. Then, we discuss the roles of PACAP and PAC1R in the activation of a variety of signaling cascades related to the physiology and diseases of the nervous system. Lastly, we examine current drug design and development of peptides and small molecules targeting PAC1R based on a number of structure- activity relationship studies and key pharmacophore elements. At present, the rational design of PAC1R-selective peptide or small-molecule therapeutics is largely hindered by the lack of structural information regarding PAC1R activation mechanisms, the PACAP-PAC1R interface, and the core segments involved in receptor activation. Understanding the molecular basis governing the PACAP interactions with its different cognate receptors will undoubtedly provide a basis for the development and/or refinement of receptor-selective therapeutics.


Assuntos
Doenças Metabólicas/tratamento farmacológico , Doenças do Sistema Nervoso/tratamento farmacológico , Peptídeos/farmacologia , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Humanos , Doenças Metabólicas/metabolismo , Modelos Moleculares , Estrutura Molecular , Doenças do Sistema Nervoso/metabolismo , Peptídeos/síntese química , Peptídeos/química , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/química , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química
9.
Chem Pharm Bull (Tokyo) ; 67(10): 1131-1138, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31316036

RESUMO

Membrane curvature formation is important for various biological processes such as cell motility, intracellular signal transmission, and cellular uptake of foreign substances. However, it remains still a challenging topic to visualize the membrane curvature formation on the cell membranes in real-time imaging. To develop and design membrane curvature-sensors, we focused on amphipathic helical peptides of proteins belonging to the Bin/Amphiphysin/Rvs (BAR) family as the starting point. BAR proteins individually have various characteristic structures that recognize different curvatures, and the derived peptides possess the potential to function as curvature sensors with a variety of recognition abilities. Peptide-based curvature sensors can have wide applications in biological research fields due to their small size, easy modification, and large production capability in comparison to protein-based sensors. In the present study, we found that an amphipathic peptide derived from sorting nexin1 (SNX1) has a curvature-recognition ability. The mutation studies of the initial peptide revealed a close correlation between the α-helicity and lipid binding ability of the peptides. In particular, the amino acids located on the hydrophobic face played a vital role in curvature recognition. The α-helix formation of the peptides was thought to serve to accommodate lipid-packing defects on the membrane surface and to maintain their binding to lipid vesicles. The structure-activity correlation found in this study have the potential to contribute to the design of peptide-based curvature sensors that will enable the capture of various life phenomena in cells.


Assuntos
Membrana Celular/química , Correlação de Dados , Peptídeos/química , Peptídeos/síntese química , Humanos , Bicamadas Lipídicas/química , Lipossomos/síntese química , Lipossomos/química , Relação Estrutura-Atividade
10.
Eur J Med Chem ; 177: 386-400, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158752

RESUMO

We explored the approach of using an analog of E-64, a well-known and hydrophilic cysteine cathepsin (CC) inhibitor, as a potent cysteine cathepsin-trapping agent (CCTA) to improve the tumor retention of low-molecular-weight, receptor-targeted radiopharmaceuticals. The synthesized hydrophilic CCTA-incorporated, NTSR1-targeted agents demonstrated a substantial increase in cellular retention upon uptake into the NTRS1-positive HT-29 human colon cancer cell line. Similarly, biodistribution studies using HT-29 xenograft mice revealed a significant and substantial increase in tumor retention for the CCTA-incorporated, NTSR1-targeted agent. The intracellular trapping mechanism of the CCTA-incorporated agents by macromolecular adduct formation was confirmed using multiple in vitro and in vivo techniques. Furthermore, utilization of the more hydrophilic CCTA greatly increased the hydrophilicity of the resulting NTSR1-targeted constructs leading to substantial decreases in most non-target tissues in contrast to our previously reported dipeptidyl acyloxymethyl ketone (AOMK) constructs. This work further confirms that the CCTA trapping approach can make significant improvements in the clinical potential of NTSR1-and other receptor-targeted radiopharmaceuticals.


Assuntos
Catepsinas/antagonistas & inibidores , Inibidores Enzimáticos/metabolismo , Peptídeos/metabolismo , Compostos Radiofarmacêuticos/metabolismo , Receptores de Neurotensina/metabolismo , Animais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Feminino , Células HT29 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lutécio/química , Camundongos SCID , Neoplasias/diagnóstico , Peptídeos/síntese química , Peptídeos/química , Radioisótopos/química , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Distribuição Tecidual
11.
Int J Nanomedicine ; 14: 4059-4069, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213815

RESUMO

Background and purpose: Traumatic brain injury (TBI) is a major disease without effective treatment. Recently, Tat-NR2B9c peptide emerged as a promising neuroprotective agent, but limited in clinical translation by it low brain penetrability. We synthesized Tat-NR2B9c loaded self-assembled activatable protein nanoparticles, termed TN-APNPs, and demonstrated that TN-APNPs enhanced the delivery of Tat-NR2B9c to the brain lesion in stroke. Herein we developed a novel approach to further engineering TN-APNPs for targeted delivery of Tat-NR2B9c to the injured brain with enhanced efficiency through conjugation of CAQK or CCAQK, a short peptide. Methods: Short peptide-conjugated TN-APNPs were synthesized by conjugated with CAQK or CCAQK via a click condensation reaction with CBT, then analyzed by dynamic light scattering, transmission electron microscopy and thrombin responsive assay. Characterization of short peptide-conjugated TN-APNPs were investigated by using cell excitotoxicity assay and transwell blood-brain-barrier model in vitro, and pharmacokinetics, IVIS imaging system and confocal analysis in TBI-bearing mice. Evaluation of therapeutic effects were analyzed by H&E staining, Elevated Plus Maze analysis and Rotarod test. Results: CAQK-conjugated TN-APNPs (C-TN-APNPs) and CCAQK-conjugated TN-APNPs (CC-TN-APNPs) were spherical in morphology and 30 nm in diameter. In vitro studies revealed that TN-APNPs, C-TN-APNPs and CC-TN-APNPs were responsive to thrombin cleavage, reduced the cytotoxicity of Tat-NR2B9c, and increased BBB permeability of Tat-NR2B9c. CC-TN-APNPs demonstrated the better circulation time, better targeting ability and penetrating efficiency to the injured brain, and better therapeutic benefits in vivo studies. Conclusion: This study demonstrated CC-TN-APNPs as a promising therapeutic for clinical management of TBI.


Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Nanopartículas/química , Peptídeos/uso terapêutico , Animais , Lesões Encefálicas Traumáticas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Portadores de Fármacos/química , Humanos , Masculino , Camundongos Endogâmicos C57BL , Nanopartículas/ultraestrutura , Peptídeos/síntese química , Peptídeos/farmacologia , Teste de Desempenho do Rota-Rod , Trombina/uso terapêutico
12.
Eur J Med Chem ; 179: 56-77, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31238251

RESUMO

The overexpression of peptide receptors in certain tumors as compared to endogeneous expression levels represents the molecular basis for the design of peptide-based tools for targeted nuclear imaging and therapy. Receptor targeting with radiolabelled peptides became a very important imaging and/or therapeutic approach in nuclear medicine and oncology. A great variety of peptides has been radiolabelled with clinical relevant radionuclides, such as radiometals and radiohalogens. However, to the best of our knowledge concise and updated reviews providing information about the biomedical application of radioiodinated peptides are still missing. This review outlines the synthetic efforts in the preparation of radioiodinated peptides highlighting the importance of radioiodine in nuclear medicine, giving an overview of the most relevant radioiodination strategies that have been employed and describes relevant examples of their use in the biomedical field.


Assuntos
Pesquisa Biomédica , Neoplasias/tratamento farmacológico , Peptídeos/farmacologia , Compostos Radiofarmacêuticos/farmacologia , Receptores de Peptídeos/antagonistas & inibidores , Animais , Humanos , Radioisótopos do Iodo , Neoplasias/metabolismo , Peptídeos/síntese química , Peptídeos/química , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Receptores de Peptídeos/biossíntese
13.
Chem Commun (Camb) ; 55(49): 7093-7096, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31155632

RESUMO

A peptidic 'nanomillipede', consisting of a worm-like nanoscale 'body' and cysteine-terminated 'legs', was synthesized, tuned (with ultrasound) and utilized to crosslink the vinyl sulfone-modified dextran to form hybrid hydrogels with soft-tissue mimicking tuneable mechanical strength, self-healing property, and tuneable shear-thinning property, thereby indicating its potential use in tissue engineering and drug delivery.


Assuntos
Hidrogéis/síntese química , Nanopartículas/química , Peptídeos/química , Sistemas de Liberação de Medicamentos , Hidrogéis/química , Estrutura Molecular , Tamanho da Partícula , Peptídeos/síntese química , Propriedades de Superfície , Engenharia Tecidual
14.
Nat Commun ; 10(1): 2412, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160596

RESUMO

Peptide self-assemblies with multiple nanostructures have great potentials in functional biomaterials, and yet the tedious and costly covalent peptide modification and the lack of facile controllability on self-assembly morphology retard the peptide-related exploration. Here we report a simple approach to fabricate a supramolecular peptide that shows programmable self-assembly with multiple morphologies and application in photodynamic therapy. Pillar[5]arene-based host-guest recognition is used to construct a supramolecular peptide, which simplify the peptide modification and promote the controllability of the self-assembly behavior. Due to the ERGDS sequences on the exterior surfaces and hydrophobic cores of self-assemblies, the nanoparticles formed from the supramolecular peptide are suitable vehicles to encapsulate a photosensitizer for photodynamic therapy. In vitro and in vivo studies demonstrate that the inherent targeting capability and supramolecular strategy greatly boost its photodynamic therapeutic efficiency. This supramolecular peptide holds promising potentials in precise cancer therapy and perspectives for the peptide modification.


Assuntos
Calixarenos/síntese química , Nanopartículas , Peptídeos/síntese química , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Células A549 , Sistemas de Liberação de Medicamentos , Células Endoteliais , Humanos , Porfirinas/administração & dosagem
15.
Microb Pathog ; 133: 103546, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31112769

RESUMO

With this study, we investigated the effect of synthetic antimicrobial peptides Pep19-2.5 and Pep194LF alone or in combination with antibiotics on S. mutans growth and biofilm formation/disruption. We also examined the cytotoxic effect of each peptide on monocytes. S. mutans was cultured in the presence of different concentrations of each peptide. We showed that Pep19-2.5 and Pep19-4LF were able to significantly (p ≤ 0.01) inhibit the growth of S. mutans. The synthetic peptides also decreased biofilm formation by S. mutans. Furthermore, both peptides reduced the viability of S. mutans in already formed biofilms. The combination of each peptide with antibiotics (penicillin/streptomycin, P/S) produced additive interactions which inhibited S. mutans growth and biofilm formation. Pep19-2.5 and Pep19-4LF were nontoxic, as they did not decrease monocyte viability and did not increase the lactate dehydrogenase activity of the exposed cells. In conclusion, synthetic peptides Pep19-2.5 and Pep19-4LF did inhibit S. mutans growth and its capacity to form biofilm. Both peptides were found to be nontoxic to monocytes. These data provide new insight into the efficacy of synthetic peptides Pep19-2.5 and Pep19-4LF against S. mutans. These peptides may thus be useful in controlling the adverse effects of this cariogenic bacterium in human.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Proteínas do Tecido Nervoso/farmacologia , Peptídeos/farmacologia , Streptococcus mutans/efeitos dos fármacos , Peptídeos Catiônicos Antimicrobianos , Biofilmes/crescimento & desenvolvimento , Sobrevivência Celular/efeitos dos fármacos , Combinação de Medicamentos , Sinergismo Farmacológico , Humanos , L-Lactato Desidrogenase/metabolismo , Testes de Sensibilidade Microbiana , Monócitos/efeitos dos fármacos , Proteínas do Tecido Nervoso/síntese química , Penicilinas/farmacologia , Peptídeos/síntese química , Streptococcus mutans/crescimento & desenvolvimento
16.
Chem Commun (Camb) ; 55(49): 6997-7000, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31112157

RESUMO

We introduced complementary interactions between peptide amphiphiles and a small fluorescence dye to develop a programmable multi-component supramolecular assembly, and intracellular delivery of the dye was controlled by the dimensions of the co-assembly, which was manipulated by the peptide design.


Assuntos
Sistemas de Liberação de Medicamentos , Corantes Fluorescentes/química , Peptídeos/química , Bibliotecas de Moléculas Pequenas/química , Tensoativos/química , Difusão Dinâmica da Luz , Células HeLa , Humanos , Peptídeos/síntese química , Tensoativos/síntese química
17.
Chem Biol Interact ; 307: 105-115, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054283

RESUMO

Neutral endopeptidase (NEP) is an enzyme implicated in development of different tumors, e.g. colorectal cancer (CRC). In this study, the anti-cancer effects of NEP inhibitors, thiorphan (synthetic compound) and sialorphin (naturally occurring pentapeptide) on CRC cells were investigated. Moreover, we synthesized some derivatives of sialorphin (alanine scan analogues: AHNPR, QANPR, QHAPR, QHNAR; N-acetylated sialorphin; C-amidated sialorphin, and C-amidated alanine scan analogues) to examine the biological activity of these inhibitors on CRC cells. The cytotoxic activity of the NEP inhibitors against CRC cell lines (SW620 and LS180) and normal human fibroblasts (HSF) was evaluated. Additionally, the influence of NEP inhibitors on proliferation, cell cycle progression, induction of apoptosis, and the level of phosphorylation of MAP kinases and mTORC1 signaling pathway proteins in CRC cells were examined. The NEP inhibitors were non-cytotoxic to HSF cells; however, most of them slightly decreased the viability and inhibited proliferation of CRC cells. The N-acetylation or C-amidation of sialorphin or its alanine scan analogues resulted in decreased or abolished anti-proliferative activity of the NEP inhibitors towards the CRC cells. Additionally, thiorphan and sialorphin enhanced the anti-proliferative activity of other CRC-cell growth inhibitors (atrial natriuretic peptide-ANP and melphalan-MEL). The mechanisms involved in the anti-proliferative effects of the tested inhibitors were mediated via NEP and associated with induction of cell cycle arrest in the G0/G1 phase, increased activity of ERK1/2, and a reduced level of phosphorylation of mTOR (Ser2448), 4E-BP1, and p70S6K. However, the NEP inhibitors did not induce apoptosis in the CRC cells. These results have indicated that thiorphan and sialorphin or its derivatives AHNPR, QANPR, QHAPR, and QHNAR have the potential to be used as agents in treatment of patients with CRC.


Assuntos
Proliferação de Células/efeitos dos fármacos , Endopeptidases/metabolismo , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia , Tiorfano/farmacologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Endopeptidases/química , Endopeptidases/genética , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Peptídeos/síntese química , Peptídeos/química , Fosfoproteínas/metabolismo , Fosforilação/efeitos dos fármacos , Inibidores de Proteases/química , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Tiorfano/química
18.
J Med Microbiol ; 68(6): 961-972, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31107198

RESUMO

PURPOSE: Antibiotic-loaded polymethylmethacrylate-based bone cement has been implemented in orthopaedics to cope with implant-related infections associated with the formation of bacterial biofilms. In the context of emerging bacterial resistance to current antibiotics, we examined the efficacy of short antimicrobial peptide-loaded bone cement in inhibiting bacterial adhesion and consequent biofilm formation on its surface. METHODOLOGY: The ability of α-helical antimicrobial peptides composed of 12 amino acid residues to prevent bacterial biofilm [methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli] formation on the surface of model implants made from polymethylmethacrylate-based bone cement was evaluated by colony-forming unit (c.f.u.) counting of bacteria released by sonication from the biofilms formed on their surfaces. The biofilms on model implant surfaces were also visualized by light microscopy after staining with tetrazolium dye (MTT) and by scanning electron microscopy. RESULTS: When incorporated in the implants, these peptides caused a mean reduction in the number of bacterial cells attached to implants' surfaces (by five orders of magnitude), and 88 % of these implants showed no bacterial adhesion after being exposed to growth media containing various bacteria. CONCLUSION: The results showed that the antibiofilm activity of these peptides was comparable to that of the antibiotics, but the peptides exhibited broader specificity than the antibiotics. Given the rapid development of antibiotic resistance, antimicrobial peptides show promise as a substitute for antibiotics for loading into bone cements.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Peptídeos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cimentos para Ossos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Peptídeos/síntese química , Polimetil Metacrilato , Próteses e Implantes/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus epidermidis/crescimento & desenvolvimento
19.
Eur J Med Chem ; 172: 174-185, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30978562

RESUMO

G-protein coupled receptors (GPCRs) are implicated in many diseases and attractive targets for drug discovery. Peptide fragments derived from protein ligands of GPCRs are commonly used as probes of GPCR function and as leads for drug development. However, these peptide fragments lack the structural integrity of their parent full-length protein ligands and often show low receptor affinity, which limits their research and therapeutic values. It remains a challenge to efficiently generate high affinity peptide inhibitors of GPCRs. We have investigated a combinational approach involving the synthetic covalent linkage of two low affinity peptide fragments to determine if the strategy can yield high affinity GPCR inhibitors. We examined this design approach using the chemokine receptor CXCR4 as a model of GPCR system. Here, we provide a proof of concept demonstration by designing and synthesizing two peptides, AR5 and AR6, that combine a peptide fragment derived from two viral ligands of CXCR4, vMIP-II and HIV-1 envelope glycoprotein gp120. AR5 and AR6 display nanomolar binding affinity, in contrast to the weak micromolar CXCR4 binding of each peptide fragment alone, and inhibit HIV-1 entry via CXCR4. Further studies were carried out for the representative peptide AR6 using western blotting and site-directed mutagenesis in conjunction with molecular dynamic simulation and binding free energy calculation to determine how the peptide interacts with CXCR4 and inhibits its downstream signaling. These results demonstrate that this combinational approach is effective for generating nanomolar active inhibitors of CXCR4 and may be applicable to other GPCRs.


Assuntos
Peptídeos/farmacologia , Receptores CXCR4/antagonistas & inibidores , Relação Dose-Resposta a Droga , Humanos , Ligantes , Modelos Moleculares , Estrutura Molecular , Peptídeos/síntese química , Peptídeos/química , Receptores CXCR4/metabolismo , Relação Estrutura-Atividade
20.
Molecules ; 24(8)2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-31014020

RESUMO

Members of the polo-like kinase (Plk) family of serine/threonine protein kinases play crucial roles in cell cycle regulation and proliferation. Of the five Plks (Plk1-5), Plk1 is recognized as an anticancer drug target. Plk1 contains multiple structural components that are important for its proper biological function. These include an N-terminal catalytic domain and a C-terminal non-catalytic polo-box domain (PBD). The PBD binds to phosphothreonine (pT) and phosphoserine-containing sequences. Blocking PBD-dependent interactions offers a potential means of down-regulating Plk1 function that is distinct from targeting its ATP-binding site. Previously, we demonstrated by tethering alkylphenyl chains from the N(π)-position of the His residue in the 5-mer PLHSpT, that we were able to access a hydrophobic "cryptic" binding pocket on the surface of the PBD, and in so doing enhance binding affinities by approximately 1000-fold. More recently, we optimized these PBD-ligand interactions using an oxime ligation-based strategy. Herein, using azide-alkyne cycloaddition reactions, we explore new triazole-containing PBD-binding antagonists. Some of these ligands retain the high PBD-binding affinity of the parent peptide, while showing desirable enhanced selectivity for the PBD of Plk1 relative to the PBDs of Plk2 and Plk3.


Assuntos
Proteínas de Ciclo Celular/antagonistas & inibidores , Peptídeos , Inibidores de Proteínas Quinases , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Peptídeos/síntese química , Peptídeos/farmacologia , Fosfosserina/química , Fosfotreonina/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Triazóis
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