RESUMO
Prion diseases are fatal infectious neurodegenerative disorders in human and animals caused by misfolding of the cellular prion protein (PrPC) into the pathological isoform PrPSc Elucidating the molecular and cellular mechanisms underlying prion propagation may help to develop disease interventions. Cell culture systems for prion propagation have greatly advanced molecular insights into prion biology, but translation of in vitro to in vivo findings is often disappointing. A wider range of cell culture systems might help overcome these shortcomings. Here, we describe an immortalized mouse neuronal astrocyte cell line (C8D1A) that can be infected with murine prions. Both PrPC protein and mRNA levels in astrocytes were comparable with those in neuronal and non-neuronal cell lines permitting persistent prion infection. We challenged astrocytes with three mouse-adapted prion strains (22L, RML, and ME7) and cultured them for six passages. Immunoblotting results revealed that the astrocytes propagated 22L prions well over all six passages, whereas ME7 prions did not replicate, and RML prions replicated only very weakly after five passages. Immunofluorescence analysis indicated similar results for PrPSc Interestingly, when we used prion conversion activity as a readout in real-time quaking-induced conversion assays with RML-infected cell lysates, we observed a strong signal over all six passages, comparable with that for 22L-infected cells. These data indicate that the C8D1A cell line is permissive to prion infection. Moreover, the propagated prions differed in conversion and proteinase K-resistance levels in these astrocytes. We propose that the C8D1A cell line could be used to decipher prion strain biology.
Assuntos
Astrócitos/patologia , Proteínas PrPC/metabolismo , Proteínas PrPSc/metabolismo , Doenças Priônicas/patologia , Agregação Patológica de Proteínas/patologia , Animais , Astrócitos/metabolismo , Linhagem Celular , Expressão Gênica , Humanos , Camundongos , Proteínas PrPC/análise , Proteínas PrPSc/análise , Doenças Priônicas/metabolismo , Agregação Patológica de Proteínas/metabolismoRESUMO
Inflammasomes are multiprotein complexes that include members of the NLR (nucleotide-binding domain leucine-rich repeat containing) family and caspase-1. Once bacterial molecules are sensed within the macrophage, the inflammasome is assembled, mediating the activation of caspase-1. Caspase-11 mediates caspase-1 activation in response to lipopolysaccharide and bacterial toxins, and yet its role during bacterial infection is unknown. Here, we demonstrated that caspase-11 was dispensable for caspase-1 activation in response to Legionella, Salmonella, Francisella, and Listeria. We also determined that active mouse caspase-11 was required for restriction of L. pneumophila infection. Similarly, human caspase-4 and caspase-5, homologs of mouse caspase-11, cooperated to restrict L. pneumophila infection in human macrophages. Caspase-11 promoted the fusion of the L. pneumophila vacuole with lysosomes by modulating actin polymerization through cofilin. However, caspase-11 was dispensable for the fusion of lysosomes with phagosomes containing nonpathogenic bacteria, uncovering a fundamental difference in the trafficking of phagosomes according to their cargo.
Assuntos
Actinas/metabolismo , Bactérias/imunologia , Caspases/metabolismo , Lisossomos/metabolismo , Fagossomos/metabolismo , Multimerização Proteica , Fatores de Despolimerização de Actina/metabolismo , Animais , Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/imunologia , Infecções Bacterianas/metabolismo , Caspase 1/deficiência , Caspase 1/genética , Caspase 1/metabolismo , Caspases/deficiência , Caspases/genética , Caspases Iniciadoras , Humanos , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fagossomos/microbiologia , FosforilaçãoRESUMO
Prion diseases are fatal infectious neurodegenerative disorders in human and animals that are caused by misfolding of the cellular prion protein (PrPC) into the infectious isoform PrPSc. No effective treatment is available for prion diseases. Metformin is a first-line medication for treatment of type 2 diabetes which is known to activate AMPK and induce autophagy through the inhibition of mammalian target of rapamycin (mTOR1) signaling. Metformin was reported to be beneficial in various protein misfolding and neurodegenerative diseases like Alzheimer's and Huntington's diseases. In this study we investigated the anti-prion effect of metformin in persistently prion-infected neuronal cells. Our data showed that metformin significantly decreased the PrPSc load in the treated cells, as shown by less PK resistant PrP in Western blots and reduced prion conversion activity in Real-Time Quaking-Induced Conversion (RT-QuIC) assay in both 22L-ScN2a and RML-ScCAD5 cells. Additionally, metformin induced autophagy as shown by higher levels of LC3-II in treated cells compared with control cells. On the other hand, our mouse bioassay showed that oral metformin at a dose of 2 mg/ml in drinking water had no effect on the survival of prion-infected mice. In conclusion, our findings describe the anti-prion effect of metformin in two persistently prion-infected neuronal cell lines. This effect can be explained at least partially by the autophagy inducing activity of metformin. This study sheds light on metformin as an anti-prion candidate for the combination therapy of prion diseases.
Assuntos
Autofagia/efeitos dos fármacos , Metformina/farmacologia , Doenças Priônicas/tratamento farmacológico , Animais , Linhagem Celular , Feminino , Camundongos Endogâmicos , Doenças Priônicas/mortalidade , Doenças Priônicas/patologia , Príons/metabolismoRESUMO
Prions are protein-based infectious agents that autocatalytically convert the cellular prion protein PrPC to its pathological isoform PrPSc Subsequent aggregation and accumulation of PrPSc in nervous tissues causes several invariably fatal neurodegenerative diseases in humans and animals. Prions can infect recipient cells when packaged into endosome-derived nanoparticles called exosomes, which are present in biological fluids such as blood, urine, and saliva. Autophagy is a basic cellular degradation and recycling machinery that also affects exosomal processing, but whether autophagy controls release of prions in exosomes is unclear. Our work investigated the effect of autophagy modulation on exosomal release of prions and how this interplay affects cellular prion infection. Exosomes isolated from cultured murine central neuronal cells (CAD5) and peripheral neuronal cells (N2a) contained prions as shown by immunoblotting for PrPSc, prion-conversion activity, and cell culture infection. We observed that autophagy stimulation with the mTOR inhibitor rapamycin strongly inhibited exosomal prion release. In contrast, inhibition of autophagy by wortmannin or CRISPR/Cas9-mediated knockout of the autophagy protein Atg5 (autophagy-related 5) greatly increased the release of exosomes and exosome-associated prions. We also show that a difference in exosomal prion release between CAD5 and N2a cells is related to differences at the level of basal autophagy. Taken together, our results indicate that autophagy modulation can control lateral transfer of prions by interfering with their exosomal release. We describe a novel role of autophagy in the prion life cycle, an understanding that may provide useful targets for containing prion diseases.
Assuntos
Autofagia , Exossomos/metabolismo , Neurônios/metabolismo , Proteínas Priônicas/metabolismo , Animais , Linhagem Celular , Exossomos/patologia , Camundongos , Camundongos Endogâmicos C57BL , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/patologiaRESUMO
Prion diseases are fatal infectious neurodegenerative disorders in humans and other animals and are caused by misfolding of the cellular prion protein (PrPC) into the pathological isoform PrPSc These diseases have the potential to transmit within or between species, including zoonotic transmission to humans. Elucidating the molecular and cellular mechanisms underlying prion propagation and transmission is therefore critical for developing molecular strategies for disease intervention. We have shown previously that impaired quality control mechanisms directly influence prion propagation. In this study, we manipulated cellular quality control pathways in vitro by stably and transiently overexpressing selected quality control folding (ERp57) and cargo (VIP36) proteins and investigated the effects of this overexpression on prion propagation. We found that ERp57 or VIP36 overexpression in persistently prion-infected neuroblastoma cells significantly reduces the amount of PrPSc in immunoblots and prion-seeding activity in the real-time quaking-induced conversion (RT-QuIC) assay. Using different cell lines infected with various prion strains confirmed that this effect is not cell type- or prion strain-specific. Moreover, de novo prion infection revealed that the overexpression significantly reduced newly formed PrPSc in acutely infected cells. ERp57-overexpressing cells significantly overcame endoplasmic reticulum stress, as revealed by expression of lower levels of the stress markers BiP and CHOP, accompanied by a decrease in PrP aggregates. Furthermore, application of ERp57-expressing lentiviruses prolonged the survival of prion-infected mice. Taken together, improved cellular quality control via ERp57 or VIP36 overexpression impairs prion propagation and could be utilized as a potential therapeutic strategy.
Assuntos
Lectinas de Ligação a Manose/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas PrPC/metabolismo , Proteínas PrPSc/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Animais , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático , Feminino , Expressão Gênica , Humanos , Lectinas de Ligação a Manose/genética , Proteínas de Membrana Transportadoras/genética , Camundongos , Isomerases de Dissulfetos de Proteínas/genéticaRESUMO
Chronic wasting disease (CWD) is a fatal neurodegenerative disease that affects cervids in North America and now Europe. No effective measures are available to control CWD. We hypothesized that active vaccination with homologous and aggregation-prone recombinant prion protein (PrP) could overcome self-tolerance and induce autoantibody production against the cellular isoform of PrP (PrPC), which would be protective against CWD infection from peripheral routes. Five groups of transgenic mice expressing elk PrP (TgElk) were vaccinated with either the adjuvant CpG alone or one of four recombinant PrP immunogens: deer dimer (Ddi); deer monomer (Dmo); mouse dimer (Mdi); and mouse monomer (Mmo). Mice were then challenged intraperitoneally with elk CWD prions. All vaccinated mice developed ELISA-detectable antibody titers against PrP. Importantly, all four vaccinated groups survived longer than the control group, with the Mmo-immunized group exhibiting 60% prolongation of mean survival time compared with the control group (183 versus 114 days post-inoculation). We tested for prion infection in brain and spleen of all clinically sick mice. Notably, the attack rate was 100% as revealed by positive CWD signals in all tested tissues when assessed with Western blotting, real-time quaking-induced conversion, and immunohistochemistry. Our pilot study in reindeer indicated appreciable humoral immune responses to Mdi and Ddi immunogens, and the post-immune sera from the Ddi-vaccinated reindeer mitigated CWD propagation in a cell culture model (CWD-RK13). Taken together, our study provides very promising vaccine candidates against CWD, but further studies in cervids are required to investigate vaccine efficacy in the natural CWD hosts.
Assuntos
Proteínas Priônicas/imunologia , Proteínas Recombinantes/imunologia , Rena/imunologia , Vacinação , Doença de Emaciação Crônica/prevenção & controle , Animais , Autoanticorpos/imunologia , Feminino , Camundongos , Camundongos Transgênicos , Doença de Emaciação Crônica/imunologiaRESUMO
Chronic inflammation is a pivotal contributor to the liver damage mediated by hepatitis C virus (HCV). The NOD-like receptor, pyrin domain-containing 3 (NLRP3) inflammasome is activated by HCV in both hepatocytes and Kupffer cells. The aim of our study was to investigate the association of nine single-nucleotide polymorphisms in four inflammasome genes (NLRP3, CARD8, IL-1ß, and IL-18) with the susceptibility to HCV infection and outcome of interferon treatment in 201 Egyptian chronic hepatitis C patients and 95 healthy controls. The genotyping was conducted using TaqMan predesigned SNP assay. In the comparative analysis, the CC genotype of the NLRP3 rs1539019 was found to be associated with the lower risk to chronic HCV infection (OR: 0.33, 95% CI: 0.17-0.62). This association was also found for the CA genotype and the A allele of the NLRP3 rs35829419 (OR: 0.18 and 0.22, respectively), in addition to the GG genotype and G allele of IL-18 rs1946518 (OR: 0.55 and 0.61, respectively). In contrast, the AA genotype of the IL-1ß rs1143629 was significantly more frequent in HCV patients (OR: 1.7, 95% CI: 1-2.86). Notably, the frequency of the AA genotype of NLRP3 rs1539019 was significantly higher in patients with lack of response (NR) to the interferon treatment (OR: 1.95, 95% CI: 1-3.7). A similar association was found for both the CC genotype and C allele of the NLRP3 rs35829419 (OR: 2.78 and 2.73, respectively) and for the TT genotype and T allele of CARD8 rs2043211 (OR: 2.64 and 1.54, respectively). Yet, the IL-1ß (rs1143629, rs1143634) and IL-18 (rs187238, rs1946518) polymorphisms did not show any significant association with response to interferon treatment. In conclusion, this study reports, for the first time, the association of genetic variations in NLRP3 with hepatitis C susceptibility and response to treatment in Egyptian patients. However, further large-scale studies are recommended to confirm our findings.
Assuntos
Hepatite C Crônica/genética , Hepatite C Crônica/terapia , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Polimorfismo Genético , Adulto , Alelos , Antivirais/uso terapêutico , Proteínas Adaptadoras de Sinalização CARD/genética , Estudos de Casos e Controles , Egito , Feminino , Predisposição Genética para Doença , Genótipo , Humanos , Inflamação , Interleucina-18/genética , Interleucina-1beta/genética , Desequilíbrio de Ligação , Masculino , Proteínas de Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Fatores de RiscoRESUMO
Autophagy is originally described as the main catabolic pathway responsible for maintaining intracellular nutritional homeostasis that involves the formation of a unique vacuole, the autophagosome, and the interaction with the endosome-lysosome pathways. This conserved machinery plays a key role in immune-protection against different invaders, including pathogenic bacteria, intracellular parasites, and some viruses like herpes simplex and hepatitis C virus. Importantly, autophagy is linked to a number of human diseases and disorders including neurodegenerative disease, Crohn's disease, type II diabetes, tumorigenesis, cardiomyopathy, and fatty liver disease. On the other hand, inflammasomes are multiprotein platforms stimulated upon several environmental conditions and microbial infection. Once assembled, the inflammasomes mediate the maturation of pro-inflammatory cytokines and promote phagosome-lysosome fusion to sustain an innate immune response. The intersections between autophagy and inflammasome have been observed in various diseases and microbial infections. This review highlights the molecular aspects involved in autophagy and inflammasome interactions during different medical conditions and microbial infections.
Assuntos
Infecções/imunologia , Inflamassomos/metabolismo , Complexos Multiproteicos/metabolismo , Doenças Neurodegenerativas/imunologia , Fagossomos/metabolismo , Animais , Autofagia/imunologia , Humanos , Imunidade Inata , Inflamassomos/imunologia , Complexos Multiproteicos/imunologiaRESUMO
CONTEXT: In Arabic folk medicine, the seeds of Phoenix dactylifera L. (Arecaceae) have been used to manage diabetes for many years. Few studies have reported the antidiabetic effect of P. dactylifera seeds; however, their effect on diabetic complications is still unexplored. OBJECTIVE: The present study investigates the protective effect of P. dactylifera seeds against diabetic complications in rats. MATERIAL AND METHODS: The aqueous suspension of P. dactylifera seeds (aqPDS) (1 g/kg/d) was orally administered to streptozotocin-induced diabetic rats for 4 weeks. The serum biochemical parameters were assessed spectrophotometrically. Furthermore, oxidative stress was examined in both liver and kidney tissues by assessment of thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), reduced glutathione, superoxide dismutase (SOD), glutathione S-transferase, and catalase. RESULTS: Oral administration of aqPDS significantly ameliorated the elevated levels of glucose (248 ± 42 versus 508 ± 60 mg/dl), urea (32 ± 3.3 versus 48.3 ± 5.6 mg/dl), creatinine (2.2 ± 0.35 versus 3.8 ± 0.37 mg/dl), ALT (29.6 ± 3.9 versus 46.4 ± 5.9 IU/l), and AST (73.3 ± 13 versus 127.8 ± 18.7 IU/l) compared with the untreated diabetic rats. In addition to significant augmentation in the activities of antioxidant enzymes, there was reduction in TBARS and NO levels and improvement of histopathological architecture of the liver and kidney of diabetic rats. DISCUSSION AND CONCLUSION: The aqPDS showed potential protective effects against early diabetic complications of both liver and kidney. This effect may be explained by the antioxidant and free radical scavenging capabilities of P. dactylifera seeds.
Assuntos
Arecaceae/química , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/farmacologia , Sementes/química , Animais , Antioxidantes/farmacologia , Diabetes Mellitus Experimental/patologia , Relação Dose-Resposta a Droga , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , SuspensõesRESUMO
Burkholderia cenocepacia is an opportunistic pathogen that causes chronic infection and induces progressive respiratory inflammation in cystic fibrosis patients. Recognition of bacteria by mononuclear cells generally results in the activation of caspase-1 and processing of IL-1ß, a major proinflammatory cytokine. In this study, we report that human pyrin is required to detect intracellular B. cenocepacia leading to IL-1ß processing and release. This inflammatory response involves the host adapter molecule ASC and the bacterial type VI secretion system (T6SS). Human monocytes and THP-1 cells stably expressing either small interfering RNA against pyrin or YFP-pyrin and ASC (YFP-ASC) were infected with B. cenocepacia and analyzed for inflammasome activation. B. cenocepacia efficiently activates the inflammasome and IL-1ß release in monocytes and THP-1. Suppression of pyrin levels in monocytes and THP-1 cells reduced caspase-1 activation and IL-1ß release in response to B. cenocepacia challenge. In contrast, overexpression of pyrin or ASC induced a robust IL-1ß response to B. cenocepacia, which correlated with enhanced host cell death. Inflammasome activation was significantly reduced in cells infected with T6SS-defective mutants of B. cenocepacia, suggesting that the inflammatory reaction is likely induced by an as yet uncharacterized effector(s) of the T6SS. Together, we show for the first time, to our knowledge, that in human mononuclear cells infected with B. cenocepacia, pyrin associates with caspase-1 and ASC forming an inflammasome that upregulates mononuclear cell IL-1ß processing and release.
Assuntos
Sistemas de Secreção Bacterianos/fisiologia , Burkholderia cenocepacia/imunologia , Proteínas do Citoesqueleto/fisiologia , Inflamassomos/fisiologia , Monócitos/microbiologia , Apoptose , Sistemas de Secreção Bacterianos/genética , Burkholderia cenocepacia/genética , Proteínas Adaptadoras de Sinalização CARD , Caspase 1/fisiologia , Linhagem Celular/microbiologia , Proteínas do Citoesqueleto/antagonistas & inibidores , Proteínas do Citoesqueleto/genética , Humanos , Interleucina-1beta/metabolismo , Monócitos/metabolismo , Fagocitose , Pirina , Interferência de RNA , RNA Interferente Pequeno/farmacologia , Proteínas Recombinantes de Fusão/fisiologiaRESUMO
Adenosine deaminase (ADA) deficiency leads to severe combined immunodeficiency (SCID). Previous clinical trials showed that autologous CD34+ cell gene therapy (GT) following busulfan reduced-intensity conditioning is a promising therapeutic approach for ADA-SCID, but long-term data are warranted. Here we report an analysis on long-term safety and efficacy data of 43 patients with ADA-SCID who received retroviral ex vivo bone marrow-derived hematopoietic stem cell GT. Twenty-two individuals (median follow-up 15.4 years) were treated in the context of clinical development or named patient program. Nineteen patients were treated post-marketing authorization (median follow-up 3.2 years), and two additional patients received mobilized peripheral blood CD34+ cell GT. At data cutoff, all 43 patients were alive, with a median follow-up of 5.0 years (interquartile range 2.4-15.4) and 2 years intervention-free survival (no need for long-term enzyme replacement therapy or allogeneic hematopoietic stem cell transplantation) of 88% (95% confidence interval 78.7-98.4%). Most adverse events/reactions were related to disease background, busulfan conditioning or immune reconstitution; the safety profile of the real world experience was in line with premarketing cohort. One patient from the named patient program developed a T cell leukemia related to treatment 4.7 years after GT and is currently in remission. Long-term persistence of multilineage gene-corrected cells, metabolic detoxification, immune reconstitution and decreased infection rates were observed. Estimated mixed-effects models showed that higher dose of CD34+ cells infused and younger age at GT affected positively the plateau of CD3+ transduced cells, lymphocytes and CD4+ CD45RA+ naive T cells, whereas the cell dose positively influenced the final plateau of CD15+ transduced cells. These long-term data suggest that the risk-benefit of GT in ADA remains favorable and warrant for continuing long-term safety monitoring. Clinical trial registration: NCT00598481 , NCT03478670 .
Assuntos
Agamaglobulinemia , Transplante de Células-Tronco Hematopoéticas , Imunodeficiência Combinada Severa , Humanos , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/terapia , Adenosina Desaminase/genética , Adenosina Desaminase/uso terapêutico , Bussulfano/efeitos adversos , Terapia Genética , Retroviridae/genéticaRESUMO
The ability of Legionella pneumophila to cause pneumonia is determined by its capability to evade the immune system and grow within human monocytes and their derived macrophages. Human monocytes efficiently activate caspase-1 in response to Salmonella but not to L. pneumophila. The molecular mechanism for the lack of inflammasome activation during L. pneumophila infection is unknown. Evaluation of the expression of several inflammasome components in human monocytes during L. pneumophila infection revealed that the expression of the apoptosis-associated speck-like protein (ASC) and the NOD-like receptor NLRC4 are significantly down-regulated in human monocytes. Exogenous expression of ASC maintained the protein level constant during L. pneumophila infection and conveyed caspase-1 activation and restricted the growth of the pathogen. Further depletion of ASC with siRNA was accompanied with improved NF-κB activation and enhanced L. pneumophila growth. Therefore, our data demonstrate that L. pneumophila manipulates ASC levels to evade inflammasome activation and grow in human monocytes. By targeting ASC, L. pneumophila modulates the inflammasome, the apoptosome, and NF-κB pathway simultaneously.
Assuntos
Proteínas do Citoesqueleto/fisiologia , Doença dos Legionários/imunologia , Monócitos/microbiologia , Apoptose , Proteínas Reguladoras de Apoptose , Proteínas Adaptadoras de Sinalização CARD , Proteínas de Ligação ao Cálcio , Caspase 1 , Proteínas do Citoesqueleto/imunologia , Humanos , Inflamação , Monócitos/imunologia , NF-kappa B/metabolismo , Transdução de SinaisRESUMO
Prion diseases are fatal infectious neurodegenerative disorders in human and animals caused by misfolding of the cellular prion protein (PrPC) into the infectious isoform PrPSc. These diseases have the potential to transmit within or between species, and no cure is available to date. Targeting the unfolded protein response (UPR) as an anti-prion therapeutic approach has been widely reported for prion diseases. Here, we describe the anti-prion effect of the chemical compound Sephin1 which has been shown to protect in mouse models of protein misfolding diseases including amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) by selectively inhibiting the stress-induced regulatory subunit of protein phosphatase 1, thus prolonging eIF2α phosphorylation. We show here that Sephin1 dose and time dependently reduced PrPSc in different neuronal cell lines which were persistently infected with various prion strains. In addition, prion seeding activity was reduced in Sephin1-treated cells. Importantly, we found that Sephin1 significantly overcame the endoplasmic reticulum (ER) stress induced in treated cells, as measured by lower expression of stress-induced aberrant prion protein. In a mouse model of prion infection, intraperitoneal treatment with Sephin1 significantly prolonged survival of prion-infected mice. When combining Sephin1 with the neuroprotective drug metformin, the survival of prion-infected mice was also prolonged. These results suggest that Sephin1 could be a potential anti-prion drug selectively targeting one component of the UPR pathway.
Assuntos
Guanabenzo/análogos & derivados , Proteínas PrPC/metabolismo , Proteínas PrPSc/metabolismo , Príons/efeitos dos fármacos , Scrapie/tratamento farmacológico , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Sinergismo Farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/metabolismo , Guanabenzo/administração & dosagem , Guanabenzo/farmacologia , Guanabenzo/uso terapêutico , Metformina/administração & dosagem , Metformina/farmacologia , Metformina/uso terapêutico , Camundongos , Neuroblastoma/patologia , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Fosforilação/efeitos dos fármacos , Proteína Fosfatase 1/antagonistas & inibidores , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/metabolismo , Scrapie/patologiaRESUMO
BACKGROUND AND STUDY AIM: Hepatitis C represents a potential public health problem worldwide. Insulin resistance (IR) and type 2 diabetes (T2D) are among the serious metabolic complications for chronic hepatitis C virus (HCV) infection. MicroRNAs (miRNAs) are a group of small non-coding RNAs which are implicated in the modulation of almost all biological processes. The objective of this study was to investigate the levels of both miR-155 and miR-34a in sera of chronic HCV patients with or without T2D. PATIENTS AND METHODS: In this study, we investigated the expression of both miR-155 and miR-34a in 80 subjects (20 HCV, 19 HCV/T2D, 21 T2D and 19 healthy controls), using quantitative real-time PCR. RESULTS: Our results revealed significantly higher levels of both miR-155 and miR-34a in chronic HCV patients compared to healthy control subjects. However, only circulating miR-155 levels showed significant decline in diabetic HCV patients compared to non-diabetic HCV group. Intriguingly, the circulating levels of miR-155 were inversely correlated with HOMA-IR, fasting blood glucose and HbA1c levels. CONCLUSION: Our findings indicate that the insulin resistance and T2D in HCV are strongly related to miR-155. This may suggest a role for miR-155 in the pathogenesis of IR caused by HCV. However, further large-scale studies are required to confirm our findings.
Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Hepatite C Crônica/fisiopatologia , Resistência à Insulina , MicroRNAs/sangue , Adulto , Biomarcadores/sangue , Glicemia/metabolismo , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/complicações , Jejum , Feminino , Hemoglobinas Glicadas/metabolismo , Hepatite C Crônica/complicações , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROCRESUMO
Prions use cellular machineries for autocatalytic propagation by conformational conversion of the cellular prion protein into the pathological isoform PrPSc. Autophagy is a basic cellular degradation and recycling machinery that delivers cargo to lysosomes. Increase of autophagic flux in cells results in enhanced delivery of PrPSc in late endosomes to lysosomal degradation, providing a therapeutic target for prion diseases. Application of chemical enhancers of autophagy to cell or mouse models of prion infection provided a solid experimental proof-of-concept for this anti-prion strategy. In addition, increasing autophagy also reduces exosomal release of prions and transfer of prion infectivity between cells. Taken together, pharmacological induction of autophagy is a promising target for containing prion diseases, and ideal candidate for future combination therapies.
Assuntos
Autofagia , Doenças Priônicas/tratamento farmacológico , Animais , Exossomos , HumanosRESUMO
Chronic wasting disease (CWD) is the most contagious prion disease. It is expanding rapidly in North America, was found recently in Europe, and the potential for transmission to humans cannot be excluded yet. We hypothesized that it is possible to prevent peripheral CWD infection and CWD prion shedding by inducing auto-antibodies against the cellular prion protein (PrPC) by active vaccination. Our objective is to overcome self-tolerance against PrP by using a multimeric recombinant PrP (recPrP) as an immunogen. We expressed in E. coli, purified and refolded four immunogens: cervid and murine recPrP in monomeric and dimeric form. Testing immunogenicity in sera of the vaccinated transgenic mice expressing cervid PrP revealed that all four immunogens effectively overcame self-tolerance against the prion protein as shown by high antibody titers. Confocal microscopy analysis revealed effective binding of post-immune sera to surface-located PrPC in both murine and cervid PrP expressing cultured cells. Remarkably, the post-immune auto-antibodies effectively inhibited CWD-induced prion conversion in RT-QuIC assay when incubated with either PrP substrate or CWD seed. Furthermore, they mitigated prion propagation in CWD-infected cervid-PrP expressing RK13 cells. Together, multimeric recombinant cervid PrP effectively overcomes self-tolerance to PrP and induces auto-antibodies that interfere with CWD conversion in vitro.
Assuntos
Autoanticorpos/imunologia , Imunização/métodos , Proteínas PrPC/imunologia , Doença de Emaciação Crônica/terapia , Animais , Linhagem Celular Tumoral , Cervos , Feminino , Camundongos , Doença de Emaciação Crônica/imunologiaRESUMO
AIM: To investigate the current management of gastric antral webs (GAWs) among adults and identify optimal endoscopic and/or surgical management for these patients. METHODS: We reviewed our endoscopy database seeking to identify patients in whom a GAW was visualized among 24640 esophagogastroduodenoscopies (EGD) over a seven-year period (2006-2013) at a single tertiary care center. The diagnosis of GAW was suspected during EGD if aperture size of the antrum did not vary with peristalsis or if a "double bulb" sign was present on upper gastrointestinal series. Confirmation of the diagnosis was made by demonstrating a normal pylorus distal to the GAW. RESULTS: We identified 34 patients who met our inclusion criteria (incidence 0.14%). Of these, five patients presented with gastric outlet obstruction (GOO), four of whom underwent repeated sequential balloon dilations and/or needle-knife incisions with steroid injection for alleviation of GOO. The other 29 patients were incidentally found to have a non-obstructing GAW. Age at diagnosis ranged from 30-87 years. Non-obstructing GAWs are mostly incidental findings. The most frequently observed symptom prompting endoscopic work-up was refractory gastroesophageal reflux (n = 24, 70.6%) followed by abdominal pain (n = 11, 33.4%), nausea and vomiting (n = 9, 26.5%), dysphagia (n = 6, 17.6%), unexplained weight loss, (n = 4, 11.8%), early satiety (n = 4, 11.8%), and melena of unclear etiology (n = 3, 8.82%). Four of five GOO patients were treated with balloon dilation (n = 4), four-quadrant needle-knife incision (n = 3), and triamcinolone injection (n = 2). Three of these patients required repeat intervention. One patient had a significant complication of perforation after needle-knife incision. CONCLUSION: Endoscopic intervention for GAW using balloon dilation or needle-knife incision is generally safe and effective in relieving symptoms, however repeat treatment may be needed and a risk of perforation exists with thermal therapies.
RESUMO
Prion diseases are fatal infectious neurodegenerative disorders that affect both humans and animals. The autocatalytic conversion of the cellular prion protein (PrPC) into the pathologic isoform PrPSc is a key feature in prion pathogenesis. AR-12 is an IND-approved derivative of celecoxib that demonstrated preclinical activity against several microbial diseases. Recently, AR-12 has been shown to facilitate clearance of misfolded proteins. The latter proposes AR-12 to be a potential therapeutic agent for neurodegenerative disorders. In this study, we investigated the role of AR-12 and its derivatives in controlling prion infection. We tested AR-12 in prion infected neuronal and non-neuronal cell lines. Immunoblotting and confocal microscopy results showed that AR-12 and its analogue AR-14 reduced PrPSc levels after only 72 hours of treatment. Furthermore, infected cells were cured of PrPSc after exposure of AR-12 or AR-14 for only two weeks. We partially attribute the influence of the AR compounds on prion propagation to autophagy stimulation, in line with our previous findings that drug-induced stimulation of autophagy has anti-prion effects in vitro and in vivo. Taken together, this study demonstrates that AR-12 and the AR-14 analogue are potential new therapeutic agents for prion diseases and possibly protein misfolding disorders involving prion-like mechanisms.
Assuntos
Autofagia/efeitos dos fármacos , Celecoxib/análogos & derivados , Proteínas PrPSc/metabolismo , Pirazóis/farmacologia , Sulfonamidas/farmacologia , Animais , Linhagem Celular Tumoral , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/patologia , Pirazóis/química , Sulfonamidas/químicaRESUMO
BACKGROUND: Insulin resistance (IR) and type 2 diabetes mellitus (T2DM) are serious extrahepatic manifestations of chronic hepatitis C virus (HCV) infection. However, the mechanism underlying the IR in chronic HCV is obscure. Hepatokines are group of liver-derived protein, which affect the glucose and lipid metabolism in several tissues. Fetuin A (also known as human α2-HS-glycoprotein) is one of the hepatokines, which was recognized as a natural inhibitor of the insulin receptor tyrosine kinase in liver and skeletal muscle. Additionally, selenoprotein P has emerged as an important hepatokine, which primarily acts as selenium transporter and has been reported to be implicated in glucose homeostasis in human. OBJECTIVE: The aim of the current case-control study was to investigate the serum levels of both fetuin A and selenoprotein P in chronic hepatitis C patients with or without T2DM and to correlate their levels with other biochemical parameters of insulin resistance. MAIN FINDINGS: Our results showed that, serum fetuin A levels increased significantly in HCV patients compared with controls (P<0.01) and surplus increase was found in HCV with concomitant T2DM (P>0.001). However, selenoprotein P levels significantly elevated only in patients with both HCV and T2DM (P<0.05) compared with the healthy subjects. Both fetuin A and selenoprotein P were positively correlated with fasting blood glucose. Yet, only fetuin A was significantly correlated to the HOMA-IR (r=0.28; P=0.03). CONCLUSIONS: These results indicate crucial roles played by fetuin A and selenoprotein P in the IR caused by HCV and that both hepatokines may be targets for the development of therapies to treat or inhibit insulin resistance associated to HCV. However, further studies on large scale should be conducted to confirm our findings.
Assuntos
Diabetes Mellitus Tipo 2/sangue , Hepatite C Crônica/sangue , Selenoproteína P/sangue , alfa-2-Glicoproteína-HS/análise , Adulto , Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Glicemia/análise , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Humanos , MasculinoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Egyptian medicine, Phoenix dactylifera L. (date palm) seeds are listed in folk remedies for the management of diabetes, liver diseases and gastrointestinal disorders. The present study was conducted to investigate the protective effect of Phoenix dactylifera L. seeds aqueous suspension against the chemically-induced hepatic injury in rats. METHODS: Liver injury was achieved by exposing Wistar rats to CCl4 (10% in olive oil; 0.5 mL/rat; IP) twice a week for 4 weeks. Along with CCl4, aqueous suspensions of raw or roasted Phoenix dactylifera seeds (1.0 g/kg) were administered orally in a daily manner. RESULTS: Our results demonstrated that Phoenix dactylifera seeds significantly improved the CCl4-induced alterations in liver function parameters (AST, ALT, ALP and albumin). Moreover, the CCl4-induced oxidative stress, represented by elevated thiobarbituric acid reactive substance (TBARS), nitric oxide and oxidative DNA damage, was ameliorated by Phoenix dactylifera seeds treatment. In addition, Phoenix dactylifera seeds restored the activities of hepatic antioxidant enzymes (superoxide dismutase and glutathione S-transferase) that were declined after CCl4 treatment. Examination of liver histopathology revealed that Phoenix dactylifera seeds attenuate the incidence of liver lesions (including vacuolization and fibroblast proliferation) triggered by CCl4 intoxication. CONCLUSION: The Phoenix dactylifera seeds could be a promising candidate for protection against the CCl4-induced liver intoxication, and this hepatoprotective effect might be attributed to the antioxidant and free radical scavenging activities.