RESUMO
Fruits are among the main natural sources of phenolic compounds (PC). These compounds exert important antioxidant properties primarily associated with the presence of hydroxyl groups in their molecular structure. Additionally, the antibacterial effects of fruit phenolic-rich extracts or individual PC commonly found in fruits have been an emerging research focus in recent years. This review discusses by first time the available literature regarding the inhibitory effects of fruit PC on pathogenic bacteria, including not only their direct effects on bacterial growth and survival, but also their effects on virulence factors and antibiotic resistance, as well as the possible mechanism underlying these inhibitory properties. The results of the retrieved studies show overall that the antibacterial effects of fruit PC vary with the target bacteria, type of PC and length of exposure to these compounds. The type of solvent and procedures used for extraction and fruit cultivar also seem to influence the antibacterial effects of phenolic-rich fruit extracts. Fruit PC have shown wide-spectrum antibacterial properties besides being effective antibiotic resistance modifying agents in pathogenic bacteria and these effects have shown to be associated with interruption of efflux pump expression/function. Furthermore, fruit PC can cause down regulation of a variety of genes associated with virulence features in pathogenic bacteria. Results of available studies indicate the depolarization and alteration of membrane fluidity as mechanisms underlying the inhibition of pathogenic bacteria by fruit PC. These data reveal fruit PC have potential antimicrobial properties, which should be rationally exploited in solutions to control pathogenic bacteria.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Frutas/química , Fenóis/farmacologia , Compostos Fitoquímicos/farmacologia , Antibacterianos/isolamento & purificação , Viabilidade Microbiana/efeitos dos fármacos , Fenóis/isolamento & purificação , Compostos Fitoquímicos/isolamento & purificação , Virulência/efeitos dos fármacosRESUMO
Goat farming is a low-cost alternative to dairy production in developing countries. In Brazil, goat production has increased in recent years due in part to the implementation of programs encouraging this activity. Mycobacterium avium ssp. paratuberculosis (MAP) is the causative agent of paratuberculosis, a disease that causes chronic granulomatous enteritis in ruminants, but MAP transmission dynamics are still poorly understood in goats. In a previously published study of our research group, 10 dairy goat farms (467 animals) from Minas Gerais state were analyzed for MAP detection; 2 fecal cultures and 11 milk samples tested positive for MAP by conventional PCR and were confirmed by sequencing. Because no clinical signs were observed over 1 yr of monitoring, we hypothesized that these MAP-positive goats could be passive shedders. Thus, in the present study, 4 positive goats (4/13) from the previous study were purchased and feces and milk samples were collected for evaluation (twice, with an interval of 3 mo between tests) by culture of MAP, IS900 PCR, or both. All analyses were negative for MAP. At the last time point, blood samples were collected for ELISA, the animals were killed, and tissues collected for tissue culture and histopathology. At necropsy, no macroscopic lesions related to paratuberculosis were observed. Similarly, no histological changes were observed and MAP in samples stained by Ziehl-Neelsen was not detected. These animals were characterized as potential passive shedders with upward contamination of the teat canal by MAP. This is the first report of the passive shedding phenomenon in goats in Brazil and it highlights the importance of identifying these animals for control programs and to ensure the quality of dairy products.
Assuntos
Derrame de Bactérias , Doenças das Cabras/microbiologia , Mycobacterium avium subsp. paratuberculosis , Paratuberculose/microbiologia , Animais , Brasil , Fezes/microbiologia , Cabras , Leite/microbiologiaRESUMO
The generation of strong pathogen-specific immune responses at mucosal surfaces where hepatitis B virus (HBV) transmission can occur is still a major challenge. Therefore, new vaccines are urgently needed in order to overcome the limitations of existing parenteral ones. Recent studies show that this may be achieved by intranasal immunization. Chitosan has gained attention as a nonviral gene delivery system; however, its use in vivo is limited due to low transfection efficiency mostly related to strong interaction between the negatively charged DNA and the positively charged chitosan. We hypothesize that the adsorption of negatively charged human serum albumin (HSA) onto the surface of the chitosan particles would facilitate the intracellular release of DNA, enhancing transfection activity. Here, we demonstrate that a robust systemic immune response was induced after vaccination using HSA-loaded chitosan nanoparticle/DNA (HSA-CH NP/DNA) complexes. Furthermore, intranasal immunization with HSA-CH NP/DNA complexes induced HBV specific IgA in nasal and vaginal secretions; no systemic or mucosal responses were detected after immunization with DNA alone. Overall, our results show that chitosan-based DNA complexes elicited both humoral and mucosal immune response, making them an interesting and valuable gene delivery system for nasal vaccination against HBV.
Assuntos
Formação de Anticorpos/imunologia , Quitosana/administração & dosagem , DNA/administração & dosagem , Antígenos de Superfície da Hepatite B/imunologia , Imunidade nas Mucosas/efeitos dos fármacos , Nanopartículas/administração & dosagem , Mucosa Nasal/imunologia , Administração Intranasal , Animais , Quitosana/química , DNA/química , Portadores de Fármacos , Feminino , Humanos , Imunização , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Mucosa Nasal/efeitos dos fármacos , Transfecção , VacinasRESUMO
In this study, we designed and synthesized a series of thiophen-2-iminothiazolidine derivatives from thiophen-2-thioureic with good anti-Trypanosoma cruzi activity. Several of the final compounds displayed remarkable trypanocidal activity. The ability of the new compounds to inhibit the activity of the enzyme cruzain, the major cysteine protease of T. cruzi, was also explored. The compounds 3b, 4b, 8b and 8c were the most active derivatives against amastigote form, with significant IC50 values between 9.7 and 6.03µM. The 8c derivative showed the highest potency against cruzain (IC50=2.4µM). Molecular docking study showed that this compound can interact with subsites S1 and S2 simultaneously, and the negative values for the theoretical energy binding (Eb=-7.39kcal·mol(-1)) indicates interaction (via dipole-dipole) between the hybridized sulfur sp(3) atom at the thiazolidine ring and Gly66. Finally, the results suggest that the thiophen-2-iminothiazolidines synthesized are important lead compounds for the continuing battle against Chagas disease.
Assuntos
Tiazolidinas/farmacologia , Tiofenos/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Linhagem Celular , Cisteína Endopeptidases , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/farmacologia , Inibidores de Cisteína Proteinase/toxicidade , Glicina/química , Camundongos , Simulação de Acoplamento Molecular , Octoxinol , Proteínas de Protozoários/antagonistas & inibidores , Tiazolidinas/síntese química , Tiazolidinas/toxicidade , Tiofenos/síntese química , Tiofenos/toxicidade , Tioureia/análogos & derivados , Tioureia/síntese química , Tioureia/farmacologia , Tioureia/toxicidade , Tripanossomicidas/síntese química , Tripanossomicidas/toxicidadeRESUMO
The dengue virus (DENV) is the causative agent of the viral infection dengue fever. In spite of all the efforts made to prevent the spread of the disease, once it is contracted, there is no specific treatment for dengue and the WHO guidelines are limited to rest and symptomatic treatment. In its reproductive cycle, DENV utilizes the NS2B-NS3pro, a serine protease, to cleave the viral polyprotein into its constituents. This enzyme is essential for the virus lifecycle, and presents an attractive target for the development of specific dengue treatments. Here we used a hybrid Quantum Mechanics and Molecular Mechanics (QM/MM) Molecular Dynamics approach and Umbrella Sampling to study the first step (acylation) of the reaction catalyzed by NS2B-NS3pro, using the Pairwise Distance Directed Gaussian PM3 (PDDG/PM3) semi-empirical Hamiltonian for the QM subsystem, and Amber ff99SB for the MM subsystem. Our results indicate that the nucleophilic attack on the substrate by Ser135 occurs in a stepwise manner, in which a proton transfer to His51 first activates Ser135, which only later attacks the substrate. The rate-determining step is the Ser135 activation, with a barrier of 24.1 kcal mol-1. Water molecules completing the oxyanion hole stabilize the negative charge formed on the carbonyl oxygen of the substrate. The final step in the process is a proton transfer from His51 to the substrate's nitrogen, which happens with a lower barrier of 5.1 kcal mol-1, and leads directly to the breakage of the peptide bond.
Assuntos
Vírus da Dengue/enzimologia , Simulação de Dinâmica Molecular , Serina Proteases , Proteínas Virais , CatáliseRESUMO
Bacterial contamination causes irreparable losses in the performance of alcoholic fermentation. Antibiotics are used to control these microorganisms, but they generate residues and cause microbial resistance. Today the only commercial product used by the mills is hops, but it is very expensive. As an alternative, the objective of this work was to evaluate the feasibility of using extracts from plants grown in the Cerrado for antimicrobial control during an alcoholic fermentation to replace antibiotics. Hydraethanolic extracts of leaves and essential oil of the following species were tested: Schinus terebinthifolius Raddi, Serjania erecta, Serjania marginata, Campomanesia adamantium and Syzygium cumini. Only the extract of Serjania marginata did not show any activity against the bacterium Bacillus sp. Both the essential oils as well as the hydroalcoholic extracts of S. terebinthifolius and C. adamantium and the extract of S. erecta showed antibacterial activity without harming the yeast, with potential to replace the hops.
Assuntos
Fermentação , Extratos Vegetais , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Bacillus , Óleos Voláteis/farmacologia , Testes de Sensibilidade Microbiana , Bactérias/efeitos dos fármacosRESUMO
MicroRNAs (miRNAs) are an abundant class of small noncoding RNA molecules that play an important role in the regulation of gene expression at the posttranscriptional level. Due to their ability to simultaneously modulate the fate of different genes, these molecules are particularly well suited to act as key regulators during immune cell differentiation and activation, and their dysfunction can contribute to pathological conditions associated with neuroinflammation. Recent studies have addressed the role of miRNAs in the differentiation of progenitor cells into microglia and in the activation process, aiming at clarifying the origin of adult microglia cells and the contribution of the central nervous system (CNS) environment to microglia phenotype, in health and disease. Altered expression of several miRNAs has been associated with Alzheimer's disease, multiple sclerosis, and ischemic injury, hence strongly advocating the use of these small molecules as disease markers and new therapeutic targets. This review summarizes the recent advances in the field of miRNA-mediated regulation of microglia development and activation. We discuss the role of specific miRNAs in the maintenance and switching of microglia activation states and illustrate the potential of this class of nucleic acids both as biomarkers of inflammation and new therapeutic tools for the modulation of microglia behavior in the CNS.
Assuntos
Sistema Nervoso Central/imunologia , MicroRNAs/imunologia , Microglia/imunologia , Doenças Neurodegenerativas/imunologia , Biomarcadores/metabolismo , Diferenciação Celular , Sistema Nervoso Central/efeitos dos fármacos , Sistema Nervoso Central/patologia , Citocinas/genética , Citocinas/imunologia , Regulação da Expressão Gênica , Humanos , Imunidade Inata/efeitos dos fármacos , Inflamação , Ativação de Macrófagos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/patologia , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Microglia/efeitos dos fármacos , Microglia/patologia , Células-Tronco Neurais/efeitos dos fármacos , Células-Tronco Neurais/imunologia , Células-Tronco Neurais/patologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Oligonucleotídeos Antissenso/farmacologiaRESUMO
There is an urgent need for expanding the number of brain banks serving psychiatric research. We describe here the Psychiatric Disorders arm of the Brain Bank of the Brazilian Aging Brain Study Group (Psy-BBBABSG), which is focused in bipolar disorder (BD) and obsessive compulsive disorder (OCD). Our protocol was designed to minimize limitations faced by previous initiatives, and to enable design-based neurostereological analyses. The Psy-BBBABSG first milestone is the collection of 10 brains each of BD and OCD patients, and matched controls. The brains are sourced from a population-based autopsy service. The clinical and psychiatric assessments were done by an expert team including psychiatrists, through an informant. One hemisphere was perfused-fixed to render an optimal fixation for conducting neurostereological studies. The other hemisphere was comprehensively dissected and frozen for molecular studies. In 20 months, we collected 36 brains. A final report was completed for 14 cases: 3 BDs, 4 major depressive disorders, 1 substance use disorder, 1 mood disorder NOS, 3 obsessive compulsive spectrum symptoms, 1 OCD and 1 schizophrenia. The majority were male (64%), and the average age at death was 67.2 ± 9.0 years. The average postmortem interval was 16 h. Three matched controls were collected. The pilot stage confirmed that the protocols are well fitted to reach our goals. Our unique autopsy source makes possible to collect a fairly number of high quality cases in a short time. Such a collection offers an additional to the international research community to advance the understanding on neuropsychiatric diseases.
Assuntos
Pesquisa Biomédica , Encéfalo/patologia , Transtornos Mentais/patologia , Bancos de Tecidos , Idoso , Idoso de 80 Anos ou mais , Brasil , Cérebro/patologia , Criopreservação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Perfusão , Fixação de TecidosRESUMO
Since clinical application of conventional cancer therapies is usually limited by drug resistance and toxic side effects, combination of chemotherapeutic agents with gene therapy appears as an attractive therapeutic strategy to overcome these issues. Being selectively expressed in tumor tissues, survivin is a promising target for the development of anticancer strategies aimed at eliminating tumor cells while sparing normal tissues. In this work, we achieved substantial protein knockdown in a number of human cell lines, namely, A549, HeLa and MCF-7 cells which overexpress survivin, after treatment with anti-survivin siRNAs, which was associated with a significant reduction of cell viability, when compared to treatment with control siRNAs. Interestingly, when the survivin-silencing approach was combined with a chemotherapeutic agent, an enhancement of the therapeutic effect was achieved. Treatment with anti-survivin siRNAs resulted in high levels of caspase 3/7 activation, and an enhancement of this effect was observed when survivin silencing was combined with vinblastine. In addition, we showed that for A549 and HeLa cells survivin silencing contributes to the reversion of cell resistance to doxorubicin. Overall, we demonstrate that the combination of a survivin-directed silencing strategy with chemotherapeutic agents constitutes a valuable approach for cancer treatment.
Assuntos
Doxorrubicina/farmacologia , Proteínas Inibidoras de Apoptose/metabolismo , Antibióticos Antineoplásicos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Western Blotting , Caspase 3/metabolismo , Caspase 7/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Citometria de Fluxo , Células HeLa , Humanos , Proteínas Inibidoras de Apoptose/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Survivina , Vimblastina/farmacologiaRESUMO
We analyzed the usefulness of a semi-tethered field running test (STR) and the relationships between indices of anaerobic power, anaerobic capacity and running performance in 9 trained male sprinters (22.2 ± 2.9 yrs, 176 ± 1 cm, 68.0 ± 9.4 kg). STR involved an all out 120 m run attached to an apparatus that enabled power calculation from force and velocity measures. Subjects also carried out a cycloergometer Wingate Anaerobic Test (WT), an all out 300 m run and had accessed their maximal accumulated oxygen deficit (MAOD) on a treadmill. Peak and mean powers attained in STR (1720 ± 221 and 1391 ± 201 W) were greater but significantly related (r = 0.82; P < 0.01) to those in the WT (808 ± 130 and 603 ± 87 W). In addition, power measures derived from the STR were stronger related to running performance compared to those from the WT (r = 0.81-0.94 vs. 0.68-0.84; P < 0.05). Relationships between MAOD and most power indices were only weak to moderate. These results support the usefulness of STR for specific power assessment in field running and suggest that anaerobic power and capacity are not related entities, irrespective of having been evaluated using similar or dissimilar exercise modes.
Assuntos
Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Corrida/fisiologia , Adulto , Limiar Anaeróbio/fisiologia , Tolerância ao Exercício/fisiologia , Humanos , Masculino , Adulto JovemRESUMO
Endocrine monitoring of non-human primates (NHP) via faecal metabolites of steroid hormones appears as a useful non-invasive alternative to evaluate the reproductive status of free living NHP, as well as of those kept in captivity but of difficult handling. However, validation is needed with plasma values before its application in the field. The aim of the present study was to monitor the different phases of the menstrual cycle from the new world NHP Sapajus apella and S. libidinosus. For this, hormonal and faecal plasma levels of E2, P4 and cortisol were assessed during different days of the menstrual cycle, together with colpocitology. The mean duration of the menstrual cycle according colpocitology was of 21.7 and 21.0 days for S. apella and S. libidinosus, respectively. These values were similar to those observed via plasma analysis, i.e. 22.7 and 20.3 days for S. apella and S. libidinosus, respectively. The day of plasmatic E2 peak was set as Day -1 and the estimated day of ovulation was set as Day 0 and occurred two days earlier in S. libidinosus than in S. apella females. In both species, it was observed a delay in faecal E2 peak of six days for S. apella and of 11 days for S. libidinosus when compared with the plasma peak. A maximum P4 plasma concentration was observed in the middle of luteal phase in S. apella and in S. libidinosus, both at around day 5. However, faecal P4 peaks were detected at days 9 and 8 in S. apella and S. libidinosus, respectively. Mean plasma and faecal cortisol levels were variable during all ovulatory cycle of S. apella and S. libidinosus females. Although no exact correlation was observed between plasmatic and faecal profile of steroid hormone, faecal samples were able to indicate ovarian cycle phase, being important to assess the reproductive status of the females applying a non-invasive method.
RESUMO
Physical exercise is a known preventive and therapeutic alternative for several cerebrovascular diseases. Therefore, the objective of the present study was to evaluate the motor performance and histomorphometry of the biceps brachii, soleus, and tibialis anterior muscles of rats submitted to a treadmill training program prior to the induction of cerebral ischemia via occlusion of the middle cerebral artery (OMCA). A total of 24 Wistar rats were distributed into four groups: Sham-Sed: sedentary control animals (n=6), who underwent sham surgery (in which OMCA did not occur); Sham+Ex: control animals exercised before the sham surgery (n=6); I-Sed: sedentary animals with cerebral ischemia (n=6); and I+Ex: animals exercised before the induction of ischemia (n=6). The physical exercise consisted of treadmill training for five weeks, 30 min/day (5 days/week), at a speed of 14 m/min. The results showed that the type-I fibers presented greater fiber area in the exercised ischemic group (I+Ex: 2347.96±202.77 µm2) compared to the other groups (Sham-Sed: 1676.46±132.21 µm2; Sham+Ex: 1647.63±191.09 µm2; I+Ex: 1566.93±185.09 µm2; P=0.0002). Our findings suggested that the angiogenesis process may have influenced muscle recovery and reduced muscle atrophy of type-I fibers in the animals that exercised before cerebral ischemia.
Assuntos
Isquemia Encefálica/complicações , Infarto da Artéria Cerebral Média , Músculo Esquelético/fisiopatologia , Atrofia Muscular/prevenção & controle , Condicionamento Físico Animal/fisiologia , Animais , Isquemia Encefálica/fisiopatologia , Modelos Animais de Doenças , Masculino , Atrofia Muscular/etiologia , Atrofia Muscular/patologia , Ratos , Ratos WistarRESUMO
In the present work, we used a novel albumin-associated lipoplex formulation, containing the cationic lipid 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (EPOPC) and cholesterol (Chol), to evaluate the antitumoral efficacy of two gene therapy strategies: immuno-gene therapy, mediated by IL-12 gene expression, and "suicide" gene therapy, mediated by HSV-tk gene expression followed by ganciclovir (GCV) treatment. Our data show that, in an animal model bearing a subcutaneous TSA (mouse mammary adenocarcinoma) tumor, intratumoral administration of the albumin-associated complexes containing the plasmid encoding IL-12 results in a strong antitumoral effect, as demonstrated by the smaller tumor size, the higher T-lymphocyte tumor infiltration and the more extensive tumor necrotic and hemorrhagic areas, as compared to that observed in animals treated with control complexes. On the other hand, the application of the "suicide" gene therapy strategy results in a significant antitumoral activity, which is similar to that achieved with the immuno-gene therapy strategy, although involving different antineoplastic mechanisms. For the tested model, albumin-associated complexes were shown to efficiently mediate intratumoral delivery of therapeutic genes, thus leading to a significant antitumoral effect. This finding is particularly relevant since TSA tumors are characterized for being poorly immunogenic, aggressive and exhibiting high proliferation capacity.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Terapia Genética/métodos , Interleucina-12/administração & dosagem , Interleucina-12/genética , Neoplasias/genética , Neoplasias/terapia , Simplexvirus/enzimologia , Timidina Quinase/administração & dosagem , Timidina Quinase/genética , Animais , Antineoplásicos , Sobrevivência Celular , DNA Viral/genética , Relação Dose-Resposta a Droga , Feminino , Ganciclovir/uso terapêutico , Interleucina-12/metabolismo , Lipossomos , Luciferases/genética , Linfócitos do Interstício Tumoral/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/patologia , Linfócitos T/imunologia , Timidina Quinase/metabolismoRESUMO
When designing molecular targeted therapeutic strategies against cancer, it is important to correlate protein expression and cell viability. However, such goal can be difficult if performed in separate assays, especially when only a fraction of cells has been efficiently transfected. Therefore, the aim of the present study was to establish a flow cytometry procedure to assess simultaneously Bcl-2 protein level and viability in small-cell lung cancer (SCLC) cells. Viability assessment was performed by staining cells with Annexin V-fluorescein isothiocyanate (FITC) and 7-aminoactinomycin D (7-AAD). Intracellular detection of Bcl-2 was carried out by immunodetection with monoclonal antibodies. Regarding viability determination, the FSC/7-AAD plot identifies the same percentage of viable cells as the FSC/Annexin V-FITC plot, although with greater sensitivity. The procedures involving cells' fixation with 1% paraformaldehyde and permeabilization with digitonin, required for intracellular Bcl-2 immunostaining did not compromise the association of 7-ADD (nor Annexin V-FITC) previously incubated with SCLC cells. It was therefore possible to simultaneously assess cell viability and Bcl-2 protein in SCLC cells. A simple, sensitive, and versatile procedure was established for the first time for the simultaneous evaluation of cell viability and intracellular detection of Bcl-2 in SCLC.
Assuntos
Citometria de Fluxo/métodos , Neoplasias Pulmonares/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Carcinoma de Pequenas Células do Pulmão/metabolismo , Anexina A5/farmacologia , Antineoplásicos/imunologia , Antineoplásicos/farmacologia , Benzamidas , Sobrevivência Celular , Inibidores Enzimáticos/farmacologia , Etoposídeo/imunologia , Etoposídeo/farmacologia , Humanos , Mesilato de Imatinib , Neoplasias Pulmonares/patologia , Piperazinas/imunologia , Piperazinas/farmacologia , Pirimidinas/imunologia , Pirimidinas/farmacologia , Carcinoma de Pequenas Células do Pulmão/patologiaRESUMO
New molecular biology techniques have uncovered the hidden role of genes in cancer. Identification of activated oncogenes, as fundamental genetic differences relative to normal cells, has made it possible to consider such genes as targets for antitumor therapy, namely by applying gene silencing strategies. In this regard, antisense oligonucleotides or small interfering RNAs, constitute promising therapeutic tools. The widespread clinical application of such molecules as modulators of gene expression, is still dependent on several aspects that limit their bioavailability, including: enhanced biological stability, favourable pharmacokinetics, enhanced tumor cell uptake and, consequently, efficient targeted delivery. One of the most promising strategies to overcome the barriers faced by gene silencing molecules, upon systemic administration, involves the use of lipid-based nanoparticles. The first part of this review aims at providing the reader with the molecular mechanism of action of the most important gene silencing molecules used in anticancer therapy. The primary obstacle for translating gene silencing technology from an effective research tool into a feasible therapeutic strategy remains its efficient delivery to the targeted cell type in vivo. Therefore, an overview of different lipid-based strategies for nucleic acid delivery will be presented on the second part. As we learn more about the pharmacokinetics and pharmacodynamics of the carrier and/or of the gene silencing molecules, it will be possible to further improve the delivery strategy that likely in the future will lead to the ideal non-viral particle for targeted cancer systemic gene silencing.
Assuntos
Inativação Gênica , Lipídeos/química , Nanopartículas , Animais , Humanos , Neoplasias/irrigação sanguínea , Neoplasias/terapia , RNA Interferente PequenoRESUMO
The use of tailored particle-based adjuvants constitutes a promising way to enhance antigen-specific humoral and cellular immune responses. However, a thorough understanding of the mechanisms underlying their adjuvanticity is crucial to generate more effective vaccines. We studied the ability of chitosan-aluminum nanoparticles (CH-Al NPs), which combine the immunostimulatory effects of chitosan and aluminum salts, to promote dendritic cell activation, assess their impact on innate and adaptive immune responses, and compare the results to those reported for conventional chitosan particles (CH-Na NPs). All tested CH-NP formulations were capable of modulating cytokine secretion by dendritic cells. CH-Al NPs promoted NLRP3 inflammasome activation, enhancing the release of IL-1ß without significantly inhibiting Th1 and Th17 cell-polarizing cytokines, IL-12p70 or IL-23, and induced DC maturation, but did not promote pro-inflammatory cytokine production on their own. In vivo results showed that mice injected with CH-Al NPs generated a local inflammatory response comparable to that elicited by the vaccine adjuvant alum. Importantly, after subcutaneous immunization with CH-Al NPs combined with the hepatitis B surface antigen (HBsAg), mice developed antigen-specific IgG titers in serum, nasal and vaginal washes. Overall, our results established CH-Al NPs as a potential adjuvant to enhance both innate and adaptive immune responses.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Alumínio/administração & dosagem , Quitosana/administração & dosagem , Antígenos de Superfície da Hepatite B/administração & dosagem , Nanopartículas/administração & dosagem , Animais , Citocinas/imunologia , Feminino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologiaRESUMO
The bacterial cytosine deaminase (CD) gene converts the non-toxic prodrug 5-fluorocytosine (5-FC) into 5-fluorouracil. We have previously shown, in a rat liver metastasis model from colon carcinoma, that intratumoral injection of a CD-expressing plasmid into the animals followed by 5-FC treatment results in the regression of the treated tumor as well as distant uninjected tumors. The aim of this study was to further analyze the mechanisms associated with tumor regression induced upon application of suicide CD/5-FC strategy. Tumor regression was associated with an increased apoptosis, the recruitment of natural killer cells, CD4- and CD8 T lymphocytes within the tumors and an increased expression of several cytokines/chemokines mRNAs. These data indicate that the CD/5-FC suicide strategy is associated with the triggering of cellular and molecular events leading to an efficient antitumor immune response involving both innate and acquired immunity.
Assuntos
Antimetabólitos/uso terapêutico , Citosina Desaminase/genética , Flucitosina/uso terapêutico , Regulação Enzimológica da Expressão Gênica/fisiologia , Genes Transgênicos Suicidas , Terapia Genética , Neoplasias Hepáticas Experimentais/terapia , Animais , Apoptose , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/patologia , Terapia Combinada , Citocinas/genética , Células Matadoras Naturais/imunologia , Lipossomos , Neoplasias Hepáticas Experimentais/imunologia , Neoplasias Hepáticas Experimentais/secundário , Masculino , Plasmídeos/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos , Transfecção , Células Tumorais CultivadasRESUMO
The use of particulate adjuvants offers an interesting possibility to enhance and modulate the immune responses elicited by vaccines. Aluminium salts have been extensively used as vaccine adjuvants, but they lack the capacity to induce a strong cellular and mucosal immune response. Taking this into consideration, in this study we designed a new antigen delivery system combining aluminium salts with chitosan. Chitosan-aluminium nanoparticles (CH-Al NPs) exhibited a mean diameter of 280nm and a positive surface charge. The newly developed CH-Al NPs are more stable at physiological environment than classical CH NPs, showing no cytotoxic effects and revealing potential as a delivery system for a wide range of model antigens. In vivo studies showed that mice immunized with hepatitis B surface antigen (HBsAg)-containing CH NPs display high anti-HBsAg IgG titers in the serum, as well as the highest antigen-specific IgG on vaginal washes. Furthermore, in contrast to mice receiving antigen alone, mice immunized with the particulate adjuvant were able to elicit IgG2c antibody titers and exhibited higher antigen-specific IFN-γ levels in splenocytes. In conclusion, we established that CH-Al NPs, combining two immunostimulants to enhance both humoral and cellular immune responses, are a safe and promising system for antigen delivery. Our findings point towards their potential in future vaccination approaches.
Assuntos
Adjuvantes Imunológicos/química , Alumínio/química , Quitosana/química , Antígenos de Superfície da Hepatite B/imunologia , Vacinas contra Hepatite B/imunologia , Células A549 , Animais , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/químicaRESUMO
This report describes a fatal case of a pet dog with major enteric signs owned by a family that has experienced cases of pulmonary tuberculosis (TB) in the household. Clinical and epidemiological aspects, imaging data, microbiological, haematological and histopathological examinations were assessed to diagnosis of disease. gyrB-RFLP, spoligotyping and MIRU-VNTR allowed molecular detection of M. tuberculosis strain from S family. The resazurin microtiter assay indicated that all isolates were resistant to isoniazid, ethambutol, ciprofloxacin, ofloxacin, streptomycin and amikacin. The public health concerns related to canine tuberculosis and risk of the dissemination by pets of M. tuberculosis pre-multidrug-resistant (PMD) to isoniazid, ethambutol and other first-line drugs used in human therapy of TB are discussed. We believe this to be the first report of PMD M. tuberculosis infection in a dog presenting mainly enteric manifestation, confirmed as S lineage by molecular methods, owned by a family in which TB has spread in the household for generations.
Assuntos
Doenças do Cão/microbiologia , Farmacorresistência Bacteriana Múltipla , Enterite/veterinária , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Pulmonar/microbiologia , Animais , Antituberculosos/farmacologia , Doenças do Cão/diagnóstico , Cães , Enterite/diagnóstico , Enterite/microbiologia , Evolução Fatal , Humanos , Isoniazida/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/isolamento & purificação , Animais de Estimação , Tuberculose Resistente a Múltiplos MedicamentosRESUMO
The objective of the present study was to evaluate changes in optic nerve head parameters, measured by confocal laser tomography, before and after trabeculectomy in order to identify outcome measures for the management of glaucoma. The optic nerve head of 22 eyes (22 patients) was analyzed by confocal laser tomography with the Heidelberg retinal tomogram (HRT) before and after trabeculectomy. The median time between the first HRT and surgery was 4.6 months (mean: 7.7 +/- 8.3) and the median time between surgery and the second HRT was 10.8 months (mean: 12.0 +/- 6.8). The patients were divided into two groups, i.e., those with the highest (group A) and lowest (group B) intraocular pressure (IOP) change after surgery. Differences in the 12 standard topographic parameters before and after surgery for each group were evaluated by the Wilcoxon signed rank test and the differences in these parameters between the two groups were compared by the Mann-Whitney rank sum test. Multiple regression analysis was used to evaluate the influence of the change in IOP (DeltaIOP and DeltaIOP%) and the changes in the other parameters. There were significant differences in the HRT measures before and after surgery in group A only for cup volume. In group B, no parameter was statistically different. The changes in group A were not significantly different than those in group B for any parameter (P > 0.004, Bonferroni correction for multiple comparisons). DeltaIOP and DeltaIOP% had a statistically significant effect on Delta cup disk area, Delta cup volume and Delta mean cup depth. Changes in cup shape size were influenced significantly only by DeltaIOP. Some optic disc parameters measured by HRT presented a significant improvement after filtering surgery, depending on the amount of IOP reduction. Long-term studies are needed to determine the usefulness of these findings as outcome measures in the management of glaucoma.