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1.
J Control Release ; 370: 707-720, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38744346

RESUMO

Immunotherapy is gaining prominence as a promising strategy for treating triple-negative breast cancer (TNBC). Neoantigens (neoAgs) and cancer-testis antigens (CTAs) are tumor-specific targets originating from somatic mutations and epigenetic changes in cancer cells. These antigens hold great promise for personalized cancer vaccines, as supported by preclinical and early clinical evidence in TNBC. This review delves into the potential of neoAgs and CTAs as vaccine candidates, emphasizing diverse strategies and delivery approaches. It also highlights the current status of vaccination modalities undergoing clinical trials in TNBC therapy. A comprehensive understanding of neoAgs, CTAs, vaccination strategies, and innovative delivery methods is crucial for optimizing neoAg-based immunotherapies in clinical practice.


Assuntos
Antígenos de Neoplasias , Vacinas Anticâncer , Imunoterapia , Neoplasias de Mama Triplo Negativas , Humanos , Vacinas Anticâncer/administração & dosagem , Vacinas Anticâncer/imunologia , Antígenos de Neoplasias/imunologia , Neoplasias de Mama Triplo Negativas/imunologia , Neoplasias de Mama Triplo Negativas/terapia , Feminino , Animais , Imunoterapia/métodos , Ensaios Clínicos como Assunto , Sistemas de Liberação de Medicamentos/métodos
2.
Nanoscale ; 15(30): 12748-12770, 2023 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-37477348

RESUMO

Aggregation of both amyloid beta (Aß) peptide and hyperphosphorylated tau proteins is the major pathological hallmark of Alzheimer's disease (AD). Moieties that carry anti-amyloidogenic potency against both of the aggregating entities are considered to be promising drug candidatures for the disease. In the current work, we have synthesized amphipathic dipeptide vesicle-templated selenium nanoparticles (RΔF-SeNPs) as potential entities to combat AD. We have investigated and established their anti-amyloidogenic activity against different peptide-based amyloid models, such as the reductionist model based on the dipeptide phenylalanine-phenylalanine (FF) derived from Aß; a model based on the hexapeptide Ac-PHF6 (306VQIVYK311) derived from tau protein; and the full-length Aß42 polypeptide-based model. We also evaluated the neuroprotective characteristics of RΔF-SeNPs against FF, Ac-PHF6, and Aß42 fibril-induced toxicity in neuroblastoma, SH-SY5Y cells. RΔF-SeNPs further exhibited neuroprotective effects in streptozotocin (STZ) treated neuronal (N2a) cells carrying AD-like features. In addition, studies conducted in an intra-cerebroventricular STZ-instigated rat model of dementia revealed that RΔF-SeNP-treated animals showed improved cognitive activity and reduced Aß42 aggregate burden in brain tissues as compared with the STZ-treated group. Moreover, in vivo brain distribution studies conducted in animal models additionally demonstrated the brain-homing ability of RΔF-SeNPs. All together, these studies supported the potency of RΔF-SeNPs as efficient and propitious disease-modifying therapeutic agents for combating AD.


Assuntos
Doença de Alzheimer , Nanopartículas , Neuroblastoma , Selênio , Ratos , Humanos , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Selênio/farmacologia , Arginina , Fenilalanina/farmacologia , Dipeptídeos , Estreptozocina/uso terapêutico , Nanopartículas/uso terapêutico , Fragmentos de Peptídeos/farmacologia
3.
Biomater Sci ; 11(10): 3469-3485, 2023 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-36961503

RESUMO

Bio-piezoelectric materials are endowed with characteristic features such as non-invasiveness, small energy attenuation and deep tissue penetrability. Thus, they have the ability to serve as both diagnostic and therapeutic modalities for targeting and treating various dreaded disorders scourging mankind. Herein, piezoelectric nanotubes derived from a modified amino acid-containing dipeptide, phenylalanine-αß-dehydrophenylalanine (Phe-ΔPhe; FΔF), possessing acoustic stimulation-triggered reactive oxygen species (ROS) generating ability, were employed and projected for achieving a piezo-active response enabled anti-cancer effect in glioma cells. A model anti-cancer drug doxorubicin (Dox) was also loaded into the nanotubes and the combined system depicted enhanced ROS production and cell killing under an acoustically developed piezo-catalytic environment. Cellular level assessment studies demonstrated that the dipeptide based piezoelectric nanotubes could lead to an increase in the cellular Ca2+ ion concentration, further inducing ROS-triggered cytotoxicity accompanied by high therapeutic efficacy in C6 glioma cells. Overall, our structures have the uniqueness of serving as acoustic stimulus-driven, wireless, and non-invasive electro-chemotherapeutic agents for enabling heightened cancer cell killing and may complement other chemotherapeutic modalities for treating the disease.


Assuntos
Eletroquimioterapia , Glioma , Nanotubos , Humanos , Espécies Reativas de Oxigênio , Glioma/tratamento farmacológico , Doxorrubicina/química , Linhagem Celular Tumoral , Fenilalanina/química , Dipeptídeos/farmacologia
4.
Front Immunol ; 13: 1005332, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36211427

RESUMO

Plasmodium falciparum Cysteine-Rich Protective Antigen (CyRPA) is an essential, highly conserved merozoite antigen that forms an important multi-protein complex (RH5/Ripr/CyRPA) necessary for erythrocyte invasion. CyRPA is a promising blood-stage vaccine target that has been shown to elicit potent strain-transcending parasite neutralizing antibodies. Recently, we demonstrated that naturally acquired immune anti-CyRPA antibodies are invasion-inhibitory and therefore a correlate of protection against malaria. Here, we describe a process for the large-scale production of tag-free CyRPA vaccine in E. coli and demonstrate its parasite neutralizing efficacy with commonly used adjuvants. CyRPA was purified from inclusion bodies using a one-step purification method with high purity (>90%). Biochemical and biophysical characterization showed that the purified tag-free CyRPA interacted with RH5, readily detected by a conformation-specific CyRPA monoclonal antibody and recognized by sera from malaria infected individuals thus indicating that the recombinant antigen was correctly folded and retained its native conformation. Tag-free CyRPA formulated with Freund's adjuvant elicited highly potent parasite neutralizing antibodies achieving inhibition of >90% across diverse parasite strains. Importantly, we identified tag-free CyRPA/Alhydrogel formulation as most effective in inducing a highly immunogenic antibody response that exhibited efficacious, cross-strain in vitro parasite neutralization achieving ~80% at 10 mg/ml. Further, CyRPA/Alhydrogel vaccine induced anti-parasite cytokine response in mice. In summary, our study provides a simple, scalable, cost-effective process for the production of tag-free CyRPA that in combination with human-compatible adjuvant induces efficacious humoral and cell-mediated immune response.


Assuntos
Vacinas Antimaláricas , Malária , Hidróxido de Alumínio , Animais , Anticorpos Monoclonais , Anticorpos Neutralizantes , Anticorpos Antiprotozoários , Cisteína , Citocinas , Escherichia coli , Adjuvante de Freund , Humanos , Camundongos , Plasmodium falciparum
5.
Infect Immun ; 90(1): e0037721, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-34694918

RESUMO

Plasmodium falciparum cysteine-rich protective antigen (CyRPA) is a conserved component of an essential erythrocyte invasion complex (RH5/Ripr/CyRPA) and a target of potent cross-strain parasite-neutralizing antibodies. While naturally acquired human RH5 antibodies have been functionally characterized, there are no similar reports on CyRPA. Thus, we analyzed the parasite-neutralizing activity of naturally acquired human CyRPA antibodies. In this regard, CyRPA human antibodies were measured and purified from malaria-infected plasma obtained from patients in central India and analyzed for their parasite neutralizing activity via in vitro growth inhibition assays (GIA). We report that, despite being susceptible to antibodies, CyRPA is a highly conserved antigen that does not appear to be under substantial immune selection pressure, as a very low acquisition rate for anti-CyRPA antibodies was reported in malaria-exposed Indians. We demonstrate for the first time that the small amounts of natural CyRPA antibodies exhibited functional parasite-neutralizing activity and that a CyRPA-based vaccine formulation induces highly potent antibodies in rabbits. Importantly, the vaccine-induced CyRPA antibodies exhibited a robust 50% inhibitory concentration (IC50) of 21.96 µg/ml, which is comparable to the IC50 of antibodies against the leading blood-stage vaccine candidate, reticulocyte-binding-like homologous protein 5 (RH5). Our data support CyRPA as a unique vaccine target that is highly susceptible to immune attack but is highly conserved compared to other leading candidates such as MSP-1 and AMA-1, further substantiating its promise as a leading blood-stage vaccine candidate.


Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/imunologia , Interações Hospedeiro-Parasita/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Proteínas de Protozoários/imunologia , Anticorpos Neutralizantes/imunologia , Especificidade de Anticorpos/imunologia , Resistência à Doença/imunologia , Ensaio de Imunoadsorção Enzimática , Eritrócitos/imunologia , Eritrócitos/parasitologia , Humanos , Vacinas Antimaláricas/imunologia , Malária Falciparum/parasitologia , Proteínas Recombinantes/imunologia
6.
Mol Pharm ; 18(10): 3832-3842, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34499836

RESUMO

Use of tumor-associated antigens for cancer immunotherapy is limited due to their poor in vivo stability and low cellular uptake. Delivery of antigenic peptides using synthetic polymer-based nanostructures has been actively pursued but with limited success. Peptide-based nanostructures hold much promise as delivery vehicles due to their easy design and synthesis and inherent biocompatibility. Here, we report self-assembly of a dipeptide containing a non-natural amino acid, α,ß-dehydrophenylalanine (ΔF), into nanotubes, which efficiently entrapped a MAGE-3-derived peptide (M3). M3 entrapped in F-ΔF nanotubes was more stable to a nonspecific protease treatment and both F-ΔF and F-ΔF-M3 showed no cellular toxicity for four cancerous and noncancerous cell lines used. F-ΔF-M3 showed significantly higher cellular uptake in RAW 267.4 macrophage cells compared to M3 alone and also induced in vitro maturation of dendritic cells (DCs). Immunization of mice with F-ΔF-M3 selected a higher number of IFN-γ secreting CD8+ T cells and CD4+ T compared to M3 alone. On day 21, a tumor growth inhibition ratio (TGI, %) of 41% was observed in a murine melanoma model. These results indicate that F-ΔF nanotubes are highly biocompatible, efficiently delivered M3 to generate cytotoxic T lymphocytes responses, and able to protect M3 from degradation under in vivo conditions. The F-ΔF dipeptide-based nanotubes may be considered as a good platform for further development as delivery agents.


Assuntos
Antígenos de Neoplasias/administração & dosagem , Sistemas de Liberação de Fármacos por Nanopartículas/administração & dosagem , Testículo/imunologia , Animais , Humanos , Imunoterapia/métodos , Células MCF-7 , Masculino , Melanoma/imunologia , Melanoma/terapia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Nanotubos de Peptídeos , Transplante de Neoplasias , Células RAW 264.7
7.
ACS Omega ; 5(7): 3365-3375, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32118151

RESUMO

Materials that exhibit responsiveness toward biological signals are currently subjected to intense research in the field of drug delivery. In our study, we tried to develop cancer-targeted and redox-responsive nanoparticles (NPs) from disulfide-linked oxidized cysteine-phenylalanine (CFO). The NPs were conjugated with folic acid (FA) to specifically target cancer cells, and the presence of disulfide bonds would enabled the disintegration of the particles in the presence of elevated levels of glutathione (GSH) in cancer cells. Anticancer drug doxorubicin (Dox) was successfully loaded inside the disulfide-linked nanoparticles (CFO-Dox-NPs), which further demonstrated stimuli-responsive drug release in the presence of GSH. We have also demonstrated enhanced uptake of FA-derivatized NPs (FA-CFO-NPs) in cancerous cells (C6 glioma and B16F10 melanoma cells) than in normal cells (HEK293T cells) due to the overexpression of FA receptors on the surface of cancer cells. Cytotoxicity studies in C6 cells and B16F10 cells further revealed enhanced efficacy of Dox loaded (FA-CFO-Dox-NPs) as compared to the native drug. The findings of this study clearly demonstrated that the disulfide-linked nanoparticle system may provide a promising selective drug delivery platform in cancer cells.

8.
Int Ophthalmol ; 39(1): 69-104, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29332228

RESUMO

PURPOSE: To analyze and compare the total proteome of aqueous humor (AH) from patients having primary angle closure glaucoma (PACG), primary open angle glaucoma (POAG) and age-related cataract. MATERIALS AND METHODOLOGY: Aqueous humor was collected from age-matched PACG, POAG and cataract patients who underwent surgery, and it was immediately stored at - 80 °C until analysis. From each sample, 25 µg of total protein was subjected to trypsin digestion and subsequently LC-MS/MS analysis was performed for the deep proteome analysis. The data acquired after the LC-MS/MS analysis were analyzed using Proteome Discoverer 1.4. The identified peptide matches were validated using percolator, at less than 1% false discovery rates. RESULTS: A total of 625, 594 and 636 proteins were identified in PACG, POAG and cataract groups, respectively (n = 9 in each group). The inter-group comparison among all these groups showed that 246 proteins were identified in all the three groups. An average of 236 ± 42, 218 ± 40 and 214 ± 62 proteins from each AH sample of PACG, POAG and cataract, respectively, was identified. There were 53 proteins commonly found in all 9 PACG AH, 59 proteins in POAG AH and 42 proteins in 9 cataracts AH samples. In the individual analysis, there were 28 proteins found in all the samples analyzed representing the "constitutive AH proteome." Spectral counting analysis of 246 proteins identified in all three group types showed significant differences in protein abundance. In proteins unique to PACG AH, 7 proteins viz. ARHGEF12, APC2, WAS, PIK3CG, ITGB1, MSN and PFN1 out of 226 were found in "Regulation of Actin Cytoskeleton" pathway, whereas in POAG 5 out of 206 proteins viz. ADCY2, ITPR1, MAPK3, MAP3K2 and TUBB1 were found in "Gap Junction" pathway. CONCLUSIONS: A qualitative as well as a quantitative comparison of proteomes of AH from PACG, POAG and age-related cataract eyes showed significant differences, thus providing clues to the disease pathophysiology.


Assuntos
Humor Aquoso/metabolismo , Catarata/metabolismo , Glaucoma de Ângulo Fechado/metabolismo , Glaucoma de Ângulo Aberto/metabolismo , Pressão Intraocular/fisiologia , Proteoma/metabolismo , Biomarcadores/metabolismo , Cromatografia Líquida , Feminino , Glaucoma de Ângulo Fechado/fisiopatologia , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Espectrometria de Massas em Tandem
9.
Pharm Res ; 35(2): 35, 2018 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-29362936

RESUMO

PURPOSE: Nanoparticles (NPs) exhibiting responsiveness towards pH variations in organs, tissue microenvironments and cellular compartments can significantly add on to the drug delivery potential. Here, we have developed NPs from an amphipathic dipeptide, Arginine-α, ß-dehydrophenylalanine (RΔF), and tried to explore their pH responsive drug delivery potential in various cancer cells. METHODS: RΔF-NPs were architectured by harnessing the process of molecular self-assembly followed by the assessment of effect of pH on NPs morphology using zetasizer, SEM and CD. FTIR and PXRD analysis of the dipeptide and doxorubicin (Dox) were carried out for compatibility assessment followed by encapsulation of Dox in RΔF-NPs. RΔF-Dox-NPs were evaluated for pH dependent release as well as for in-vitro cellular internalization and efficacy in cancer cells. RESULTS: RΔF self-assembled to form monodispersed particles at pH 7. SEM analysis revealed a loss of overall particle morphology along with particle aggregation at highly acidic and basic pH respectively. The NPs demonstrated a slow and sustained release behaviour at pH 7 (97.64 ± 4.71% after 36 h) in comparison to pH 2 (90.27 ± 1.45% after 8 h) and pH 10 (96.39 ± 3.87% after 12 h). In-vitro efficacy studies carried-out in various cancer cells revealed that RΔF-Dox-NPs exhibited higher efficacy with 1.65, 1.95 and 13.34 fold lower IC50 values in comparison to Dox in C6, HCT-116 and AGS cell lines. CONCLUSIONS: RΔF-Dox-NPs with higher drug release at acidic pH, enhanced internalization in cancer cells along with higher cytotoxic potential can act as effective pH responsive drug delivery systems.


Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Dipeptídeos/química , Doxorrubicina/administração & dosagem , Portadores de Fármacos/química , Nanopartículas/química , Animais , Antibióticos Antineoplásicos/farmacocinética , Arginina/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Doxorrubicina/farmacocinética , Liberação Controlada de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Fenilalanina/análogos & derivados , Fenilalanina/química , Ratos
10.
Cancer Invest ; 35(6): 431-442, 2017 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-28537455

RESUMO

Lung cancer is the leading cause of cancer deaths and the overall 5-year survival rate is less than 17%. Hyperthermia is an alternative approach for the treatment of lung cancer and is associated with fewer side effects. We employed ironoxide nanoparticles in inducing localized hyperthermia in lung cancer cells using a pulsed electromagnetic field (PEMF). We synthesized, characterized and determined the uptake of dipeptide-coated iron oxide nanoparticles. Further, their ability in inducing localized hyperthermia in PEMF on lung cancer cells was assessed. Results showed nanoparticles are non-cytotoxic and showed enhanced cellular uptake in lung cancer cells. In vivo studies in nude mice lung tumor xenografts confirmed the presence in the tumors. Lung cancer cells pretreated with dipeptide-coated magnetic nanoparticles upon PEMF exposure induced cell death.


Assuntos
Campos Eletromagnéticos , Neoplasias Pulmonares/genética , Nanopartículas de Magnetita/uso terapêutico , Animais , Apoptose , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Nus
11.
Sci Rep ; 6: 31167, 2016 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-27507432

RESUMO

Nanostructures including hydrogels based on peptides containing non protein amino acids are being considered as platform for drug delivery because of their inherent biocompatibility and additional proteolytic stability. Here we describe instantaneous self-assembly of a conformationally restricted dipeptide, LeuΔPhe, containing an α,ß-dehydrophenylalanine residue into a highly stable and mechanically strong hydrogel, under mild physiological aqueous conditions. The gel successfully entrapped several hydrophobic and hydrophilic drug molecules and released them in a controlled manner. LeuΔPhe was highly biocompatible and easily injectable. Administration of an antineoplastic drug entrapped in the gel in tumor bearing mice significantly controlled growth of tumors. These characteristics make LeuΔPhe an attractive candidate for further development as a delivery platform for various biomedical applications.


Assuntos
Hidrogéis , Peptídeos/química , Dicroísmo Circular , Microscopia Eletrônica de Transmissão , Conformação Proteica , Espectroscopia de Infravermelho com Transformada de Fourier
12.
ACS Chem Neurosci ; 7(5): 615-23, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-26835536

RESUMO

Amyloid-ß aggregation is a major etiological phenomenon in Alzheimer's disease. Herein, we report peptide-based inhibitors that diminish the amyloid load by obviating Aß aggregation. Taking the hexapeptide fragment, Aß32-37, as lead, more than 40 new peptides were synthesized. Upon evaluation of the newly synthesized hexapeptides as inhibitors of Aß toxicity by the MTT-based cell viability assay, a number of peptides exhibited significant Aß aggregation inhibitory activity at sub-micromolar concentration range. A hexapeptide (1) showed complete mitigation of Aß toxicity in the cell culture assay at 2 µM. In the ThT fluorescence assay, upon incubation of Aß with this peptide, we observed no increase in the ThT fluorescence relative to control. The secondary structure estimation by circular dichroism spectroscopy and morphological examination by transmission electron microscopy further confirmed the results.


Assuntos
Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/toxicidade , Fragmentos de Peptídeos/química , Agregados Proteicos/fisiologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Células PC12 , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Ratos
13.
Chem Commun (Camb) ; 49(80): 9155-7, 2013 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-23986270

RESUMO

Monomeric hIAPP significantly destabilizes both model and live cell membranes by increasing membrane fluidity. This interaction with membranes happens via carpet formation followed by lipid extraction in a concentration dependent manner and thus we propose that hIAPP aggregation prior to membrane interaction may not be necessary for its cytotoxicity.


Assuntos
Membrana Celular/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Bicamadas Lipídicas/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/química , Dicroísmo Circular , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/toxicidade , Bicamadas Lipídicas/química , Fluidez de Membrana , Microscopia de Fluorescência , Método de Monte Carlo , Estrutura Secundária de Proteína , Rodaminas/química
14.
Biochim Biophys Acta ; 1830(11): 5193-203, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23876294

RESUMO

BACKGROUND: Three de novo designed low molecular weight cationic peptides (IJ2, IJ3 and IJ4) containing an unnatural amino acid α,ß-didehydrophenylalanine (∆Phe) exhibited potent antifungal activity against fluconazole (FLC) sensitive and resistant clinical isolates of Candida albicans as well as non-albicans and other yeast and filamentous pathogenic fungi. In the present study, their synthesis, susceptibility of different fungi and the mechanism of anti-candidal action have been elucidated. METHODS: The antimicrobial peptides (AMPs) were synthesized by solid-phase method and checked for antifungal activity against different yeasts and fungi by broth microdilution method. Anti-candidal mode of action of the peptides was investigated through detecting membrane permeabilization by confocal microscopy, Reactive Oxygen Species (ROS) generation by fluorometry, apoptosis and necrosis by flow cytometry and cell wall damage using Scanning and Transmission Electron Microscopy. RESULTS AND CONCLUSIONS: The MIC of the peptides against C. albicans and other yeast and filamentous fungal pathogens ranged between 3.91 and 250µM. All three peptides exhibited effect on multiple targets in C. albicans including disruption of cell wall structures, compromised cell membrane permeability leading to their enhanced entry into the cells, accumulation of ROS and induction of apoptosis. The peptides also showed synergistic effect when used in combination with fluconazole (FLC) and caspofungin (CAS) against C. albicans. GENERAL SIGNIFICANCE: The study suggests that the AMPs alone or in combination with conventional antifungals hold promise for the control of fungal pathogens, and need to be further explored for treatment of fungal infections.


Assuntos
Antifúngicos/síntese química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Peptídeos/síntese química , Peptídeos/farmacologia , Apoptose/efeitos dos fármacos , Caspofungina , Permeabilidade da Membrana Celular/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Sinergismo Farmacológico , Equinocandinas/farmacologia , Fluconazol/farmacologia , Hemólise/efeitos dos fármacos , Lipopeptídeos , Necrose/tratamento farmacológico , Necrose/metabolismo , Espécies Reativas de Oxigênio/metabolismo
15.
J Biol Chem ; 288(23): 16775-16787, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-23592791

RESUMO

Drug-resistant pathogenic fungi use several families of membrane-embedded transporters to efflux antifungal drugs from the cells. The efflux pump Cdr1 (Candida drug resistance 1) belongs to the ATP-binding cassette (ABC) superfamily of transporters. Cdr1 is one of the most predominant mechanisms of multidrug resistance in azole-resistant (AR) clinical isolates of Candida albicans. Blocking drug efflux represents an attractive approach to combat the multidrug resistance of this opportunistic human pathogen. In this study, we rationally designed and synthesized transmembrane peptide mimics (TMPMs) of Cdr1 protein (Cdr1p) that correspond to each of the 12 transmembrane helices (TMHs) of the two transmembrane domains of the protein to target the primary structure of the Cdr1p. Several FITC-tagged TMPMs specifically bound to Cdr1p and blocked the efflux of entrapped fluorescent dyes from the AR (Gu5) isolate. These TMPMs did not affect the efflux of entrapped fluorescent dye from cells expressing the Cdr1p homologue Cdr2p or from cells expressing a non-ABC transporter Mdr1p. Notably, the time correlation of single photon counting fluorescence measurements confirmed the specific interaction of FITC-tagged TMPMs with their respective TMH. By using mutant variants of Cdr1p, we show that these TMPM antagonists contain the structural information necessary to target their respective TMHs of Cdr1p and specific binding sites that mediate the interactions between the mimics and its respective helix. Additionally, TMPMs that were devoid of any demonstrable hemolytic, cytotoxic, and antifungal activities chemosensitize AR clinical isolates and demonstrate synergy with drugs that further improved the therapeutic potential of fluconazole in vivo.


Assuntos
Antifúngicos/farmacologia , Azóis , Materiais Biomiméticos/farmacologia , Candida albicans/metabolismo , Farmacorresistência Fúngica/efeitos dos fármacos , Proteínas Fúngicas/antagonistas & inibidores , Peptídeos/farmacologia , Antifúngicos/química , Materiais Biomiméticos/química , Candida albicans/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Humanos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Peptídeos/química , Estrutura Secundária de Proteína
16.
Chem Commun (Camb) ; 49(26): 2688-90, 2013 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-23435449

RESUMO

hIAPP fibrillization implicated in Type 2 diabetes pathology involves formation of oligomers toxic to insulin producing pancreatic ß-cells. We report design, synthesis, 3D structure and functional characterization of dehydrophenylalanine (ΔF) containing peptides which inhibit hIAPP fibrillization. The inhibitor protects ß-cells from hIAPP induced toxicity.


Assuntos
Polipeptídeo Amiloide das Ilhotas Pancreáticas/antagonistas & inibidores , Peptídeos/farmacologia , Cristalografia por Raios X , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Modelos Moleculares , Peptídeos/síntese química , Peptídeos/química , Conformação Proteica , Relação Estrutura-Atividade
17.
PLoS One ; 7(10): e46713, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23056416

RESUMO

Broadly neutralizing antibodies to HIV-1 usually develops in chronic infections. Here, we examined the basis of enhanced sensitivity of an env clone amplified from cross neutralizing plasma of an antiretroviral naïve chronically infected Indian patient (ID50 >600-fold higher compared to other autologous env clones). The enhanced autologous neutralization of pseudotyped viruses expressing the sensitive envelope (Env) was associated with increased sensitivity to reagents and monoclonal antibodies targeting distinct sites in Env. Chimeric viruses constructed by swapping fragments of sensitive Env into resistant Env backbone revealed that the presence of unique residues within C2V3 region of gp120 governed increased neutralization. The enhanced virus neutralization was also associated with low CD4 dependence as well as increased binding of Env trimers to IgG1b12 and CD4-IgG2 and was independent of gp120 shedding. Our data highlighted vulnerabilities in the Env obtained from cross neutralizing plasma associated with the exposure of discontinuous neutralizing epitopes and enhanced autologous neutralization. Such information may aid in Env-based vaccine immunogen design.


Assuntos
Produtos do Gene env/metabolismo , HIV-1/metabolismo , Linhagem Celular , Produtos do Gene env/genética , HIV-1/genética , Humanos , Mutagênese Sítio-Dirigida
18.
Chembiochem ; 12(16): 2495-501, 2011 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-21905193

RESUMO

Ubiquitinated cytoplasmic inclusions of TDP-43 and its C-terminal cleavage products are the pathological hallmarks of amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitinated inclusions. The C-terminal fragments (CTFs) of TDP-43 are increasingly considered to play an important role in its aggregation and in disease. Here, we employed a set of synthetic peptides spanning the length of the TDP-43 CTF (220-414) in order to find out its core aggregation domains. Two regions, one in the RRM-2 domain (246-255) and the other in the C-terminal domain (311-320) of TDP-43, stand out as highly aggregation prone. Studies done on recombinant purified TDP-43 CTF and its three mutants, in which these sequences were deleted individually and together, suggested that the 311-320 region has a more crucial role to play than the 246-255 in its aggregation. The study helps in defining specific peptide sequences that might form the core of TDP-43 aggregation. Identification of these sequences could help in designing peptide based inhibitors of TDP-43 aggregation.


Assuntos
Proteínas de Ligação a DNA/química , Sequência de Aminoácidos , Benzotiazóis , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Luz , Peptídeos/síntese química , Peptídeos/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Espalhamento de Radiação , Tiazóis/química , Tiazóis/metabolismo
19.
Peptides ; 32(8): 1732-40, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21693143

RESUMO

In the present work, we investigated the antifungal activity of two de novo designed, antimicrobial peptides VS2 and VS3, incorporating unnatural amino acid α,ß-dehydrophenylalanine (ΔPhe). We observed that the low-hemolytic peptides could irreversibly inhibit the growth of various Candida species and multidrug resistance strains at MIC(80) values ranging from 15.62 µM to 250 µM. Synergy experiments showed that MIC(80) of the peptides was drastically reduced in combination with an antifungal drug fluconazole. The dye PI uptake assay was used to demonstrate peptide induced cell membrane permeabilization. Intracellular localization of the FITC-labeled peptides in Candida albicans was studied by confocal microscopy and FACS. Killing kinetics, PI uptake assay, and the intracellular presence of FITC-peptides suggested that growth inhibition is not solely a consequence of increased membrane permeabilization. We showed that entry of the peptide in Candida cells resulted in accumulation of reactive oxygen species (ROS) leading to cell necrosis. Morphological alteration in Candida cells caused by the peptides was visualized by electron microscopy. We propose that de novo designed VS2 and VS3 peptides have multiple detrimental effects on target fungi, which ultimately result in cell wall disruption and killing. Therefore, these peptides represent a good template for further design and development as antifungal agents.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Oligopeptídeos/farmacologia , Peptídeos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Antifúngicos/síntese química , Antifúngicos/química , Candida albicans/crescimento & desenvolvimento , Parede Celular/metabolismo , Testes de Sensibilidade Microbiana , Oligopeptídeos/síntese química , Oligopeptídeos/química , Peptídeos/síntese química , Peptídeos/química
20.
Anal Chem ; 83(14): 5526-34, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21619052

RESUMO

Development of noninvasive methods for tuberculosis (TB) diagnosis, with the potential to be administered in field situations, remains as an unmet challenge. A wide array of molecules are present in urine and reflect the pathophysiological condition of a subject. With infection, an alteration in the molecular constituents is anticipated, characterization of which may form a basis for TB diagnosis. In the present study volatile organic compounds (VOCs) in human urine derived from TB patients and healthy controls were identified and quantified using headspace gas chromatography/mass spectrometry (GC/MS). We found significant (p < 0.05) increase in the abundance of o-xylene (6.37) and isopropyl acetate (2.07) and decreased level of 3-pentanol (0.59), dimethylstyrene (0.37), and cymol (0.42) in TB patients compared to controls. These markers could discriminate TB from healthy controls and related diseases like lung cancer and chronic obstructive pulmonary disorder. This study suggests a possibility of using urinary VOCs for the diagnosis of human TB.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Tuberculose/diagnóstico , Tuberculose/urina , Compostos Orgânicos Voláteis/urina , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Reprodutibilidade dos Testes , Adulto Jovem
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