RESUMO
Tuftsin-PhosphorylCholine (TPC) is a novel bi-specific molecule which links tuftsin and phosphorylcholine. TPC has shown immunomodulatory activities in experimental mouse models of autoimmune diseases. We studied herein the effects of TPC ex vivo on both peripheral blood mononuclear cells (PBMCs) and temporal artery biopsies (TABs) obtained from patients with giant cell arteritis (GCA) and age-matched disease controls. GCA is an immune-mediated disease affecting large vessels. Levels of 18 cytokines in supernatants, PBMC viability, T helper (Th) cell differentiation of PBMCs and gene expression in TABs were analyzed. Treatment ex vivo with TPC decreased the production of IL-1ß, IL-2, IL-5, IL-6, IL-9, IL-12(p70), IL-13, IL-17A, IL-18, IL-21, IL-22, IL-23, IFNγ, TNFα, GM-CSF by CD3/CD28 activated PBMCs whereas it negligibly affected cell viability. It reduced Th1 and Th17 differentiation while did not impact Th22 differentiation in PBMCs stimulated by phorbol 12-myristate 13-acetate plus ionomycin. In inflamed TABs, treatment with TPC down-regulated the production of IL-1ß, IL-6, IL-13, IL-17A and CD68 gene expression. The effects of TPC were comparable to the effects of dexamethasone, included as the standard of care, with the exception of a greater reduction of IL-2, IL-18, IFNγ in CD3/CD28 activated PBMCs and CD68 gene in inflamed TABs. In conclusion our results warrant further investigations regarding TPC as an immunotherapeutic agent in GCA and potentially other autoimmune and inflammatory diseases.
Assuntos
Anti-Inflamatórios/uso terapêutico , Dexametasona/uso terapêutico , Arterite de Células Gigantes/tratamento farmacológico , Imunoterapia/métodos , Fosforilcolina/análogos & derivados , Subpopulações de Linfócitos T/imunologia , Células Th1/imunologia , Tuftsina/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Diferenciação Celular , Células Cultivadas , Citocinas/metabolismo , Combinação de Medicamentos , Feminino , Humanos , Ativação Linfocitária , Masculino , Fosforilcolina/uso terapêuticoRESUMO
Bleomycin is an anticancer antibiotic effective against a range of human malignancies. Yet its usefulness is limited by serious side effects. In this study, we converted bleomycin into a prodrug by covalently linking 2-sulfo, 9 fluorenylmethoxycarbonyl (FMS) to the primary amino side chain of bleomycin. FMS-bleomycin lost its efficacy to bind transition metal ions and therefore was converted into an inactive derivative. Upon incubation in vitro under physiological conditions, the FMS-moiety undergoes spontaneous hydrolysis, generating native bleomycin possessing full anti-bacterial potency. FMS hydrolysis and reactivation takes place with a t1/2 value of 17⯱â¯1â¯h. In silico simulation predicts a narrow therapeutic window in human patients of seven hours, starting 40â¯min after administration. In mice, close agreement was obtained between the experimental and the simulated pharmacokinetic profiles for FMS-bleomycin. FMS-bleomycin is thus shown to be a classical prodrug: it is inactive at the time of administration and the non-modified (active) bleomycin is released with a desirable pharmacokinetic profile following administration, suggesting it may have therapeutic value in the clinic.
Assuntos
Antibióticos Antineoplásicos/farmacocinética , Bleomicina/farmacocinética , Fluorenos/química , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/química , Bleomicina/administração & dosagem , Bleomicina/química , Cátions Bivalentes/química , Simulação por Computador , Escherichia coli/efeitos dos fármacos , Hidrólise , Concentração Inibidora 50 , Masculino , Camundongos , Camundongos Endogâmicos ICR , Testes de Sensibilidade Microbiana , Modelos Biológicos , Pró-Fármacos/administração & dosagem , Pró-Fármacos/química , Pró-Fármacos/farmacocinética , Zinco/químicaRESUMO
Improved clinical findings of inflammatory bowel disease (IBD) upon treatment with helminthes and their ova were proven in animal models of IBD and in human clinical studies. The immunomodulatory properties of several helminthes were attributed to the phosphorylcholine (PC) molecule. We assessed the therapeutic potential of tuftsin-PC conjugate (TPC) to attenuate murine colitis. Colitis was induced by Dextransulfate-Sodium-Salt (DSS) in drinking water. TPC was given by daily oral ingestion (50 µg/0.1 ml/mouse or PBS) starting at day -2. Disease activity index (DAI) score was followed daily and histology of the colon was performed by H&E staining. Analysis of the cytokines profile in distal colon lysates was performed by immunoblot. Treatment of DSS induced colitis with TPC prevented the severity of colitis, including a reduction in the DAI score, less shortening of the colon and less inflammatory activity in histology. The immunoblot showed that the colitis preventive activity of TPC was associated with downregulation of colon pro-inflammatory IL-1ß, TNFα and IL-17 cytokines expression, and enhancement of anti-inflammatory IL-10 cytokine expression. In the current study, we demonstrated that TPC treatment can prevent significantly experimental colitis induction in naïve mice. We propose the TPC as a novel potential small synthetic molecule to treat colitis.
Assuntos
Colite/patologia , Fatores Imunológicos/farmacologia , Fosforilcolina , Tuftsina/farmacologia , Animais , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/imunologia , Citocinas/metabolismo , Sulfato de Dextrana/efeitos adversos , Modelos Animais de Doenças , Humanos , Fatores Imunológicos/administração & dosagem , Fatores Imunológicos/química , Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos , Índice de Gravidade de Doença , Tuftsina/administração & dosagem , Tuftsina/químicaRESUMO
In areas where helminths infections are common, autoimmune diseases are rare. Treatment with helminths and ova from helminths, improved clinical findings of inflammatory bowel disease, multiple-sclerosis and rheumatoid-arthritis. The immunomodulatory functions of some helminths were attributed to the phosphorylcholine (PC) moiety. We aimed to decipher the tolerogenic potential of Tuftsin-PC (TPC) compound in mice genetically prone to develop lupus. Lupus prone NZBXW/F1 mice received subcutaneously TPC (5 µg/1 ml), 3 times a week starting at 14 weeks age. Autoantibodies were tested by ELISA, T-regulatory-cells by FACS, cytokines profile by RT-PCR and cytokines protein levels by DuoSet ELISA. Glomerulonephritis was addressed by detection of proteinuria, and immunoglobulin complex deposition in the mesangium of the kidneys of the mice by immunofluorescence. Our results show that TPC attenuated the development of glomerulonephritis in lupus prone mice, in particular, it ameliorated proteinuria (p < 0.02), and reduced immunoglobulin deposition in the kidney mesangium. TPC also enhanced the expression of TGFß and IL-10 (p < 0.001), and inhibited the production of IFNγ and IL-17 (p < 0.03). TPC Significantly enhanced the expansion of CD4+CD25+FOXP3+ T-regulatory cells (Tregs) phenotype in the treated mice. These data indicate that TPC hampered lupus development in genetically lupus prone mice which was exemplified by moderate glomerulonephritis, attenuation of pro-inflammatory cytokines and enhancement of anti-inflammatory cytokines expression, as well as Tregs expansion. Our results propose harnessing novel natural therapy for lupus patients.
Assuntos
Mesângio Glomerular/efeitos dos fármacos , Glomerulonefrite/tratamento farmacológico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Nefrite Lúpica/tratamento farmacológico , Fosforilcolina/administração & dosagem , Linfócitos T Reguladores/efeitos dos fármacos , Tuftsina/administração & dosagem , Animais , Autoanticorpos/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Fatores de Transcrição Forkhead/metabolismo , Mesângio Glomerular/imunologia , Humanos , Injeções Subcutâneas , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos NZB , Fosforilcolina/análogos & derivados , Fosforilcolina/síntese química , Linfócitos T Reguladores/imunologia , Tuftsina/síntese químicaRESUMO
Most chemotherapeutic agents are blood-brain barrier (BBB) impermeants. HIV-1-derived TAT protein variants contain a transmembrane domain, which may enable them to cross the BBB and reach the brain. Here we synthesized CAYGRKKRRQRRR, a peptide containing a cysteine moiety attached to the N terminus of the transmembrane domain (C-TAT peptide), and studied its effects in an in vitro BBB model, which we found to reflect penetration by a receptor-independent pathway. Incubation of the brain capillary endothelial cell monolayer with 0.3-0.6 µmol/ml of this C-TAT peptide, for a period of 1-2 h, destabilizes brain capillary endothelial cell monolayer and introduces the ability of impermeant therapeutic agents including high molecular weight proteins to penetrate it substantially. The cysteinyl moiety at position 1 of the C-TAT peptide contributes largely to the destabilizing potency and the penetration efficacy of impermeant substances. The destabilizing effect was reversed using heparin. In summary, experimental conditions allowing a significant increase in entry of impermeant low and high molecular weight substances from the luminal (blood) to the abluminal side (brain) were found in an in vitro BBB model reflecting in vivo protein penetrability by a receptor-independent pathway.
Assuntos
Células Endoteliais/metabolismo , Infecções por HIV/metabolismo , HIV-1/metabolismo , Peptídeos/metabolismo , Proteínas/metabolismo , Produtos do Gene tat do Vírus da Imunodeficiência Humana/metabolismo , Animais , Barreira Hematoencefálica , Encéfalo/metabolismo , Infecções por HIV/virologia , HIV-1/genética , Humanos , Modelos Biológicos , Peso Molecular , Peptídeos/genética , Permeabilidade , Transporte Proteico , Proteínas/química , Suínos , Produtos do Gene tat do Vírus da Imunodeficiência Humana/química , Produtos do Gene tat do Vírus da Imunodeficiência Humana/genéticaRESUMO
We found that human serum albumin (HSA) contains a single binding domain for derivatives of long-chain fatty acid (LCFA)-like molecules in which the carboxylate is replaced by sulfonate. Accordingly, we have synthesized 16-sulfo-hexadecanoic acid-N-hydroxysuccinimide ester [HO(3)S-(CH(2))(15)-CONHS], an agent that reacts selectively with the amino side chains of peptides and proteins. A macromolecule containing a single 16-sulfohexadecanoate moiety associating with albumin with a K(a) value of 0.83 ± 0.08 × 10(6) M(-1), a sufficient affinity to extend the actions in vivo of such short-lived peptides and proteins. Subcutaneous administration of insulin-NHCO-(CH(2))(15)-SO(3)(-) into mice facilitated a glucose-lowering effect 4.3 times in duration and 6.6 times in area under the curve (AUC) as compared to an in vitro equipotent amount of Zn(2+)-free insulin. Similarly, subcutaneous and intravenous administration of exendin-4-NHCO-(CH(2))(15)-SO(3)(-) to mice yielded prolonged and stable reduction in glucose level, 5-9-fold longer than that of exendin-4. Also, a single subcutaneous administration of human interferon-α2-[NH-CO-(CH(2))(15)-SO(3)(-)](3) to mice yielded circulating antiviral activity over a period of 40 h. In conclusion, a simple, hydrophilic reagent has been engineered, synthesized, and studied. Its linkage to peptides and proteins in a monomodified fashion yielded hydrophilic, prolonged acting derivatives, due to their acquired ability to associate with serum albumin after administration.
Assuntos
Desenho de Fármacos , Hipoglicemiantes/metabolismo , Hipoglicemiantes/farmacocinética , Peptídeos/metabolismo , Peptídeos/farmacocinética , Albumina Sérica/metabolismo , Sequência de Aminoácidos , Animais , Disponibilidade Biológica , Glicemia/metabolismo , Ácidos Graxos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Masculino , Camundongos , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/farmacologia , Ligação Proteica , Especificidade por SubstratoRESUMO
Antiphospholipid syndrome (APS) is characterized by thromboembolic phenomena and recurrent fetal loss associated with elevated circulating anti-phospholipid/beta2glycoprotein-I(ß2GPI)-binding-antibodies(Abs). Individual APS patients harbor diverse clusters of circulating anti-ß2GPI Abs, targeting different epitopes on the ß2GPI molecule. Our novel approach was to construct a peptide composed of ß2GPI-ECs-binding-site (phospholipids-membrane), named "EMBI". EMBI exert dual activities: a) At first EMBI prevented ß2GPI ECs binding, thus reduced by 89% the binding of ß2GPI/anti-ß2GPI to the cells in comparison with 9.3% inhibition by EMBI scrambled form (scEMBI). b) Longer exposure of ECs to EMBI resulted in intracellular EMBI penetration which did not prevent ß2GPI/anti-ß2GPI binding to HUVEC. Surprisingly, ß2GPI/anti-ß2GPI did not activate ECs harboring EMBI, illustrated by prevention of E-selectin and tissue factor (TF) expression. The inhibition of TF mRNA transcription was illustrated by quantitative RT-PCR. EMBI decreased the expression of phosphorylated JNK1/2, p38, HSP27 and enhanced phosphorylation of glycogen synthase kinase-3ß (pGSK3ß). Knocking down the GSK3ß expression by siRNA-GSK3ß, reduced the TF expression by ß2GPI/anti-ß2GPI-exposed-HUVEC. In-vivo, EMBI significantly decreased the percentage of fetal loss in naïve mice infused with anti-ß2GPI Abs, p<0.04. Thus, the dual activity of EMBI may introduce EMBI as a potential novel candidate peptide, to treat patients with APS.
Assuntos
Síndrome Antifosfolipídica/fisiopatologia , Células Endoteliais/metabolismo , Inibidores Enzimáticos/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/metabolismo , Peptídeos/farmacologia , Tromboplastina/metabolismo , Animais , Anticorpos Antifosfolipídeos/imunologia , Anticorpos Antifosfolipídeos/metabolismo , Síndrome Antifosfolipídica/enzimologia , Modelos Animais de Doenças , Selectina E/metabolismo , Células Endoteliais/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Feminino , Morte Fetal/imunologia , Morte Fetal/prevenção & controle , Regulação Enzimológica da Expressão Gênica/imunologia , Quinase 3 da Glicogênio Sintase/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/síntese química , Fosfolipídeos/imunologia , Fosfolipídeos/metabolismo , Fosforilação/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Conformação Proteica , RNA Mensageiro/metabolismo , Tromboplastina/genética , beta 2-Glicoproteína I/química , beta 2-Glicoproteína I/imunologia , beta 2-Glicoproteína I/farmacologiaRESUMO
A family of monomodified bovine serum albumin (BSA) linked to methotrexate (MTX) through a variety of spacers was prepared. All analogues were found to be prodrugs having low MTX-inhibitory potencies toward dihydrofolate reductase in a cell-free system. The optimal conjugates regenerated their antiproliferative efficacies following entrance into cancerous glioma cell lines and were significantly superior to MTX in an insensitive glioma cell line. A BSA-MTX conjugate linked through a simple ethylene chain spacer, containing a single peptide bond located 8.7 Å distal to the protein back bone, and apart from the covalently linked MTX by about 12 Å, was most effective. The inclusion of an additional disulfide bond in the spacer neither enhanced nor reduced the killing potency of this analogue. Disrupting the native structure of the carrier protein in the conjugates significantly reduced their antiproliferative activity. In conclusion, we have engineered BSA-MTX prodrug analogues which undergo intracellular reactivation and facilitate antiproliferative activities following their entrance into glioma cells.
RESUMO
The common use of dental and orthopedic implants calls for special attention to the immune response leading to peri-prosthetic bone loss and implant failure. In addition to the well-established microbial etiology for oral implant failure, wear debris and in particular titanium (Ti) particles (TiP) in the implant vicinity are an important trigger of inflammation and activation of bone resorption around oral and orthopedic implants, presenting an unmet medical need. Here, we employed bacterial-derived lipopolysaccharides (LPS) to model infection and TiP to model aseptic inflammation and osteolysis. We assessed inflammation in vitro by measuring IL1ß, IL6 and TNFα mRNA expression in primary macrophages, osteoclastogenesis in RANKL-induced bone marrow derived pre-osteoclasts and osteolysis in vivo in a mouse calvarial model. We also assessed the trans-epithelial penetrability and safety of the tested compound in rats. Our results show that a lipophilic super-active derivative of vasoactive intestinal peptide (VIP), namely stearyl-norleucine-VIP (SNV) presented superior anti-inflammatory and anti-osteoclastogenic effects compared to VIP in vitro. In the bacterial infection model (LPS), SNV significantly reduced IL1ß expression, while VIP increased IL6 expression. In the aseptic models of osteolysis, SNV showed greater suppression of in vitro osteoclastogenesis than VIP, and significantly inhibited inflammation-induced osteolysis in vivo. We also observed that expression levels of the VIP receptor VPAC-2, but not that of VPAC-1, dramatically decreased during osteoclast differentiation. Importantly, SNV previously shown to have an increased stability compared to VIP, showed here significant trans-epithelial penetration and a clean toxicological profile, presenting a novel drug candidate that could be applied topically to counter both aseptic and infection-related bone destruction.
RESUMO
Human serum albumin (HSA) is efficiently taken up by cancer cells as a source of carbon and energy. In this study, we prepared a monomodified derivative of HSA covalently linked to an EDTA derivative and investigated its efficacy to shuttle weakly anti-proliferative EDTA associating ligands such as vanadium, into a cancer cell line. HSA-S-MAL-(CH2)2-NH-CO-EDTA was found to associate both with the vanadium anion (+5) and the vanadium cation (+4) with more than thrice the associating affinity of those ligands toward EDTA. Both conjugates internalized into glioma tumor cell line via caveolae-mediated endocytosis pathway and showed potent anti-proliferative capacities. IC50 values were in the range of 0.2 to 0.3 µM, potentiating the anti-proliferative efficacies of vanadium (+4) and vanadium (+5) twenty to thirty fold, respectively. HSA-EDTA-VO++ in particular is a cancer permeable prodrug conjugate. The associated vanadium (+4) is not released, nor is it active anti-proliferatively prior to its engagement with the cancerous cells. The bound vanadium (+4) dissociates from the conjugate under acidic conditions with half maximal value at pH 5.8. In conclusion, the anti-proliferative activity feature of vanadium can be amplified and directed toward a cancer cell line. This is accomplished using a specially designed HSA-EDTA-shuttling vehicle, enabling vanadium to be anti-proliferatively active at the low micromolar range of concentration.
RESUMO
Amyloids are pathological fibrillar aggregates of proteins related to over 20 diseases. Amyloid fibers are characterized by the cross-beta motif, which is minimally defined as a series of beta-strands extended perpendicular to the fiber axis, joined by hydrogen bonds parallel to the fiber direction. Several structures, all in agreement with the cross-beta definition, have been proposed for specific amyloids. We study the correlation among the suprastructural chirality, molecular structure, and molecular chirality of amyloids. Here we investigate the suprastructure chirality of different (all-S) serum amyloid A (SAA) truncated peptides. We found that the suprastructure chirality of amyloid fibers from segments SAA(2-6), SAA(1-11) and the majority of those from SAA(2-9) is left-handed, which is consistent with the beta-sheet protofilament model. In contrast, SAA(1-12) and SAA(2-12) as well as SAA(1-12), where the C-terminal aspartic acid was point mutated to either leucine or alanine, form right-handed helical amyloid fibers. Such a suprastructure switch indicates a molecular change in the protofilament structure. This is supported by the behavior observed in the FTIR spectra, where the amide I peak of all of the right-handed fibers is red shifted relative to the left-handed amyloid fibers. This work is a case study where isolated short fragments of SAA containing the same amyloidogenic core sequence fold into different amyloid structures. We show that core sequences, supposed to start the misfolding aggregation of the full-length amyloid peptides, may have structures different from those assumed by the isolated segments.
Assuntos
Peptídeos/química , Proteína Amiloide A Sérica/química , Sequência de Aminoácidos , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Mutação , Conformação Proteica , Proteína Amiloide A Sérica/genética , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
chelators can modulate ß-amyloid accumulation, protect against tau hyperphosphorylation, and block metal-related oxidative stress, and thereby hold considerable promise as effective anti-AD drugs. At present, a growing interest is focusing on increasing the efficacy and targeting of chelators through drug design. To this end, we have developed a new class of multifunctional prochelators from three FDA- approved drugs rasagiline, rivastigmine, and donepezil or tacrine. HLA20 A was designed by merging the important pharmacophores of rasagiline, rivastigmine, and donepezil into our newly developed multifunctional chelator HLA20. M30D was constructed using the key pharmacophoric moieties from rasagiline, rivastigmine, and tacrine. Experiments showed that both compounds possess potent anti-acetylcholinesterase (AChE) activity in vitro with weak inhibition of butyrylcholinesterase (BuChE), and without significant metal-binding activity. M30D was found also to be a highly potent MAO A inhibitor with moderate inhibition of MAO B in vitro. Both HLA20 and M30D can be activated by inhibition of AChE to release active chelators HLA20 and M30, respectively. HLA20 and M30 have been shown to be able to modulate amyloid precursor protein regulation and beta-amyloid reduction, suppress oxidative stress, and passivate excess metal ions (Fe, Cu, and Zn). Compared with the activated chelator HLA20 or M30, both HLA20A and M30D exhibited lower cytotoxicity in SH-SY5Y neuroblastoma cells, substantiating the prochelator strategy for minimizing toxicity associated with poor targeted chelators.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Quelantes/uso terapêutico , Indanos/química , Fármacos Neuroprotetores/uso terapêutico , Inibidores da Colinesterase/uso terapêutico , Humanos , Estresse Oxidativo , FosforilaçãoRESUMO
The hygiene hypothesis claims that the lack of exposure to microorganisms in developed countries correlates with a rise in the incidence of autoimmune diseases. It was also found that helminths are able to modulate the immune response in hosts in order to survive. Consequently, several successful trials using helminths as a treatment for autoimmune patients have been reported. The helminth derivative, phosphorylcholine (PC), was discovered as an immunomodulatory molecule. We have recently shown in a murine model that when a conjugate of tuftsin and PC, termed TPC, is prophylactically administered before the onset of glomerulonephritis, it attenuates the development of systemic lupus erythematosus (SLE). The current study aimed to examine the TPC effect on the gut microbiome in a mouse model of lupus. TPC treatment altered the gut composition in the mice with active lupus, in correlation with a significant decrease in glomerulonephritis, followed by an increased level of anti-inflammatory interleukin 10 (IL-10), decreased levels of proinflammatory mediators, and expansion of the T regulatory cell population. Importantly, we found that TPC treatment altered the mouse gut microbiome composition, in correlation with a significant decrease in protein secretion and improved disease parameters. The major effects of TPC treatment on the gut microbiome included decreased abundances of Akkermansia and increased abundance of several genera, including Turicibacter, Bifidobacterium, unclassified Mogibacteriaceae, unclassified Clostridiaceae, Adlercreutzia, Allobaculum, and Anaeroplasma. Overall, our results associate microbial changes with the immunomodulation of glomerulonephritis in mice with lupus. IMPORTANCE Recently, several papers referred to the association of different bacteria with lupus in mice and humans. This is the first report to demonstrate the effect of a compound derived from helminths on the induction of remission in mice with lupus and its association with a bacterial change. We show that several genera, including Akkermansia, are associated with clinical and serological parameters of lupus, while other genera, including butyrate-producing bacteria, are associated with amelioration of disease following tuftsin and phosphorylcholine treatment.
RESUMO
Amyloids are pathological fibrillar aggregates of proteins related to more than 20 different diseases. Amyloid fibers have a characteristic cross-beta structure consisting of a series of beta-strands extended perpendicular to the fiber axis and joined by hydrogen bonds parallel to the fiber direction. Fibril aggregation results in helical suprastructures. Here we used high-resolution SEM and cryo-SEM for the study of chirality in the amyloid suprastructure. We found that amyloids of Abeta1-40 and hen lysozyme form at all hierarchical levels always and only left-handed helices. In contrast, amyloid fibers formed by the N-terminal sequence of serum amyloid A (SAA1-12) consist of right-handed helices exclusively. Consistently, the peptide enantiomer, formed of (R)-aminoacids, aggregates exclusively in left-handed helices. We conclude that the opposite handedness of the SAA1-12 amyloids is an intrinsic feature of the peptide structure. The left-handed chirality observed for the Abeta1-40 and hen lysozyme amyloid suprastructures is consistent with the conventional beta-sheet structural model. In contrast, the right-handedness observed in (all-S) SAA1-12 fibers indicates that the cross-beta structure of SAA1-12 fibers is probably not formed of beta-sheets. Whatever the answer to the dilemma of the right-handed helicity of SAA1-12 amyloid fibers is, its existence shows that the supramolecular chirality of amyloid fibers is not only dictated by the molecular chirality of the component molecules but also by their structural organization.
Assuntos
Peptídeos beta-Amiloides/química , Muramidase/química , Fragmentos de Peptídeos/química , Proteína Amiloide A Sérica/química , Animais , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Conformação ProteicaRESUMO
Affecting an estimated 5% of adults over 65 years of age, Parkinson's disease and Alzheimer's disease are the most common neurodegenerative disorders. Accumulating evidence suggests that oxidative stress induced by the breakdown of iron homeostasis is a major contributor to the neuronal loss observed in neurodegeneration. Thus, brain-permeable iron chelators may present potential therapeutic benefits. In the present study, iron-chelating hydroxamate groups were introduced into the NAP (NAPVSIPQ) peptide, whose neuroprotective qualities have been widely demonstrated. Our experiments revealed that the novel dihydroxamate peptide 3 is capable of inhibiting iron-catalyzed hydroxyl radical formation and lipid peroxidation, abilities that are not part of the repertoire of its parent peptide. In addition, peptide 3 was superior to native NAP in protecting human neuroblastoma cell cultures against the toxicity of hydrogen peroxide. These results suggest that NAP-based iron chelators deserve further investigation in the search for drug candidates for neurodegeneration.
Assuntos
Antioxidantes/síntese química , Ácidos Hidroxâmicos/síntese química , Quelantes de Ferro/síntese química , Fármacos Neuroprotetores/síntese química , Oligopeptídeos/síntese química , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Compostos Férricos/química , Compostos Ferrosos/química , Humanos , Peróxido de Hidrogênio/farmacologia , Ácidos Hidroxâmicos/química , Ácidos Hidroxâmicos/farmacologia , Radical Hidroxila/química , Técnicas In Vitro , Quelantes de Ferro/química , Quelantes de Ferro/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Estresse Oxidativo , Ratos , Ratos Sprague-DawleyRESUMO
The different clinical entities of osteochondromas, hereditary multiple exostoses (HME) and non-familial solitary exostosis, are known to express localized exostoses in their joint metaphyseal cartilage. In the current study biopsies of osteochondromas patients were screened with respect to a number of cellular and molecular parameters. Specifically, cartilaginous biopsy samples of nine HME patients, 10 solitary exostosis patients and 10 articular cartilages of control subjects were collected and cell cultures were established. Results obtained showed that one of the two HME samples that underwent DNA sequencing analysis (HME-1) had a novel mutation for an early stop codon, which led to an aberrant protein, migrating at a lower molecular weight position. The EXT-1 mRNA and protein levels in chondrocyte cultures derived from all nine HME patients were elevated, compared with solitary exostosis patients or control subjects. Furthermore, cell cultures of HME patients had significantly decreased pericellular heparan sulphate (HS) in comparison with cultures of solitary exostosis patients or control subjects. Immunohistochemical staining of tissue sections and Western blotting of cell cultures derived from HME patients revealed higher levels of heparanase compared with solitary exostosis patients and of control subjects. Further investigations are needed to determine whether the low pericellular HS levels in HME patients stem from decreased biosynthesis of HS, increased degradation or a combination of both. In conclusion, it appears that due to a mutated glycosyltransferase, the low content of pericellular HS in HME patients leads to the anatomical deformations with exostoses formation. Hence, elevation of HS content in the pericellular regions should be a potential molecular target for correction.
Assuntos
Condrócitos/metabolismo , Exostose Múltipla Hereditária/genética , Exostose/genética , N-Acetilglucosaminiltransferases/genética , Especificidade de Anticorpos , Sequência de Bases , Estudos de Casos e Controles , Células Cultivadas , Condrócitos/patologia , Análise Mutacional de DNA , Exostose/patologia , Expressão Gênica , Glucuronidase/análise , Glucuronidase/genética , Glicosaminoglicanos/análise , Glicosaminoglicanos/genética , Humanos , Immunoblotting/métodos , Imuno-Histoquímica , Dados de Sequência Molecular , N-Acetilglucosaminiltransferases/análise , N-Acetilglucosaminiltransferases/imunologia , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodosRESUMO
Dysfunction of the ubiquitin-proteasome system (UPS) and accumulation of iron in substantia nigra (SN) are implicated in the pathogenesis of Parkinson's disease (PD). UPS dysfunction and iron misregulation may reinforce each other's contribution to the degeneration of dopamine (DA) neurons. In the present study, we use a new brain-permeable iron chelator, VK-28 [5-(4-(2-hydroxyethyl) piperazin-1-yl (methyl)-8-hydroxyquinoline], and its derivative M30 [5-(N-methyl-N-propargyaminomethyl)-8-hydroxyquinoline] in vivo to test their neuroprotective and neurorestorative properties against proteasome inhibitor (lactacystin) -induced nigrostriatal degeneration. Bilateral microinjections of lactacystin (1.25 microg/side) into the mouse medial forebrain bundle were performed. Administration of VK-28 (5 mg/kg, once a day) or M30 (5 mg/kg, once a day) was applied intraperitoneally 7 days before or after the lactacystin microinjection until the mice were sacrificed 28 days after microinjection. We found that VK-28 and M30 both significantly improved behavioral performances and attenuated lactacystin-induced DA neuron loss, proteasomal inhibition, iron accumulation, and microglial activation in SN. In addition, M30 restored the Bcl-2 level, which was suppressed after lactacystin injection. These findings suggest that brain-permeable iron chelators can improve DA neuron survival under UPS impairment. Furthermore, M30, a derivative of VK-28 and neuroprotective agent rasagiline, may serve as a better neuroprotective therapy for PD.
Assuntos
Acetilcisteína/análogos & derivados , Barreira Hematoencefálica/metabolismo , Dopamina/metabolismo , Quelantes de Ferro/farmacologia , Degeneração Neural/induzido quimicamente , Degeneração Neural/prevenção & controle , Neurônios/patologia , Substância Negra/patologia , Acetilcisteína/toxicidade , Animais , Cabras , Hidroxiquinolinas/farmacocinética , Hidroxiquinolinas/farmacologia , Quelantes de Ferro/farmacocinética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Coelhos , Substância Negra/efeitos dos fármacosRESUMO
We synthesized two carminic acid (7-alpha-d-glucopyranosyl-9,10-dihydro-3,5,6,8-tetrahydroxy-1-methyl-9,10-dioxo-2-anthracene carboxlic acid, CA)-GnRH conjugates to be used as a model for potential photoactive targeted compounds. CA was conjugated to the epsilon-amino group of [d-Lys(6)]GnRH through its carboxylic moiety or via a beta-alanine spacer (beta-ala). Redox potentials of CA and its conjugates were determined. We used electron spin resonance (ESR) and spin trapping techniques to study the light-stimulated redox properties of CA and its CA-GnRH conjugates. Upon irradiation, the compounds stimulated the formation of reactive oxygen species (ROS), that is, singlet oxygen ((1)O(2)) and oxygen radicals (O(2)(-*) and OH(*)). Both conjugates exhibited higher ROS production than the non-conjugated CA. The bioactivity properties of the CA conjugates and the parent peptide, [d-Lys(6)]GnRH, were tested on primary rat pituitary cells. We found that the conjugates preserved the bioactivity of GnRH as illustrated by their capability to induce ERK phosphorylation and LH release.
Assuntos
Carmim/análogos & derivados , Hormônio Liberador de Gonadotropina/química , Hipófise/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Animais , Carmim/química , Células Cultivadas , Espectroscopia de Ressonância de Spin Eletrônica , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Radicais Livres , Hormônio Luteinizante/metabolismo , Oxirredução , Fosforilação , Fotoquímica , Hipófise/citologia , Hipófise/metabolismo , Ratos , Oxigênio SingleteRESUMO
A novel small molecule named tuftsin-phosphorylcholine (TPC), which is linked to the biological activity of helminths, was constructed. The current study address the effect of TPC treatment in established collagen-induced arthritis (CIA) mice and propose TPC bi-functional activity. TPC treatment was initiated when clinical score was 2 to 4. Arthritis scores in TPC treated mice were lower compared to mice treated with vehicle (P < 0.001). Joint staining showed normal joint structure in TPC-treated mice compared to control groups treated with phosphate buffered saline (PBS), phosphorylcholine, or tuftsin, which exhibited severely inflamed joints. TPC enhanced anti-inflammatory response due to increased IL-10 secretion, and reduced pro-inflammatory cytokine secretion (IL-1-ß, IL-6, TNF-αP < 0.001). Furthermore, TPC therapy increased expansion of CD4+CD25+FOXP3+T regulatory cells and IL-10+CD5+CD1d+B regulatory cells. We propose that the immunomodulatory activity of TPC can be a result of a bi-specific activity of TPC: (a) The tuftsin part of the TPC shifts RAW macrophage cells from pro-inflammatory macrophages M1 to anti-inflammatory M2-secreting IL-10 (P < 0.001) through neuropilin-1 and (b) TPC significantly reduce mouse TLR4 expression via NFkB pathway by HEKTM cells (P < 0.02) via the phosphorylcholine site of the molecule. Our results indicate that TPC, significantly ameliorated established CIA by its immunomodulatory activity. These data could lead to a novel self bi-functional small molecule for treating patients with progressive RA.
Assuntos
Artrite Experimental/tratamento farmacológico , Helmintos/metabolismo , Fosforilcolina/uso terapêutico , Tuftsina/uso terapêutico , Animais , Artrite Experimental/patologia , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/metabolismo , Modelos Animais de Doenças , Células HEK293 , Humanos , Interleucina-10/metabolismo , Interleucina-1beta/metabolismo , Articulações/patologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos DBA , NF-kappa B/metabolismo , Neuropilina-1/metabolismo , Fosforilcolina/farmacologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismo , Receptor 4 Toll-Like/efeitos dos fármacos , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , Tuftsina/farmacologiaRESUMO
The antiphospholipid syndrome (APS) is characterized by the presence of pathogenic autoantibodies against beta2-glycoprotein-I (beta2GPI). The factors causing production of anti-beta2GPI remain unidentified, but an association with infectious agents has been reported. Recently, we identified a hexapeptide (TLRVYK) that is recognized specifically by a pathogenic anti-beta2GPI mAb. In the present study we evaluated the APS-related pathogenic potential of microbial pathogens carrying sequences related to this hexapeptide. Mice immunized with a panel of microbial preparations were studied for the development of anti-beta2GPI autoantibodies. IgG specific to the TLRVYK peptide were affinity purified from the immunized mice and passively infused intravenously into naive mice at day 0 of pregnancy. APS parameters were evaluated in the infused mice on day 15 of pregnancy. Following immunization, high titers of antipeptide [TLRVYK] anti-beta2GPI Ab's were observed in mice immunized with Haemophilus influenzae, Neisseria gonorrhoeae, or tetanus toxoid. The specificity of binding to the corresponding target molecules was confirmed by competition and immunoblot assays. Naive mice infused with the affinity-purified antipeptide Ab's had significant thrombocytopenia, prolonged activated partial thromboplastin time and elevated percentage of fetal loss, similar to a control group of mice immunized with a pathogenic anti-beta2GPI mAb. Our study establishes a mechanism of molecular mimicry in experimental APS, demonstrating that bacterial peptides homologous with beta2GPI induce pathogenic anti-beta2GPI Ab's along with APS manifestations.