Suchergebnisse

AbstractFreshwater grazers are suitable organisms to investigate the fate of environmental pollutants, such as weathered multi-walled carbon nanotubes (wMWCNTs). One key process is the uptake of ingested materials into digestive or absorptive cells. To address this, we investigated the localization of wMWCNTs in the intestinal tracts of the mud snail Lymnaea stagnalis (L. stagnalis) and the mayfly Rhithrogena semicolorata (R. semicolorata). In L. stagnalis, bundles of wMWCNTs could be detected in the midgut lumen, whereas only single wMWCNTs could be detected in the lumina of the digestive gland. Intracellular uptake of wMWCNTs was detected by transmission electron microscopy (TEM) but was restricted to the cells of the digestive gland. In larvae of R. semicolorata, irritations of the microvilli and damages in the apical parts of the epithelial gut cells were detected after feeding with 1 to 10 mg/L wMWCNTs. In both models, we detected fibrillar structures in close association with the epithelial cells that formed peritrophic membranes (PMs). The PM may cause a reduced transmission of wMWCNT bundles into the epithelium by forming a filter barrier and potentially protecting the cells from the wMWCNTs. As a result, the uptake of wMWCNTs into cells is rare in mud snails and may not occur at all in mayfly larvae. In addition, we monitor physiological markers such as levels of glycogen or triglycerides and the RNA/DNA ratio. This ratio was significantly affected in L. stagnalis after 24 days with 10 mg/L wMWCNTs, but not in R. semicolorata after 28 days and 10 mg/L wMWCNTs. However, significant effects on the energy status of R. semicolorata were analysed after 28 days of exposure to 1 mg/L wMWCNTs. Furthermore, we observed a significant reduction of phagosomes per enterocyte cell in mayfly larvae at a concentration of 10 mg/L wMWCNTs (p < 0.01).

The aim of this work was to evaluate the effects of Anagrapha falcifera (AfMNPV) multiple nucleopolyhedrovirus passages in the S. cosmioides caterpillar's biology at different times of infection and histological changes that the virus could cause in the caterpillar midgut, seeking correlate histopathologic effects to the effectiveness of this virus as a potential biological control of this pest. Larvae were infected with seven days of development, by using three different passages of AfMNPV on S. cosmioides (F1, F4 and F7, which is the first, fourth and seventh passages, respectively) and the control treatment. Compared biology assays with the same treatments for analyzing behavior and mortality of caterpillars were performed concomitantly. The midgut morphology was compared between infected and uninfected larvae. The digestive tubes were collected at 24, 72 and 144 hours of infection (20 tubes/treatment/time of infection). After collection, the digestive tubes were fixed in Karnovsky, processed, stained with Hematoxylin-Eosin, and examined under a light microscope. The biology results of F4 and F7treatments, showed a drastic reduction in locomotion and feeding from the fourth day after infection and higher cumulative mortality rate compared to the control and F1. All treatments caused morphological changes in the midgut of S. cosmioides, in the three times of infection, with the greatest changes occurring at the epithelium. The AfMNPV, in the three passages tested in S. cosmioides, caused behavioral and morphological changes in the midgut, indicating that it can be a promising agent for biological control of this pest.

Background & Aims: Acinar cells constitute 90% of the pancreas epithelium, are polarized, and secrete digestive enzymes. These cells play a crucial role in pancreatitis and pancreatic cancer. However, there are limited models to study normal acinar cell differentiation in vitro. The aim of this work was to generate and characterize purified populations of pancreatic acinar cells from embryonic stem (ES) cells. Methods: Reporter ES cells (Ela-pur) were generated that stably expressed both β-galactosidase and puromycin resistance genes under the control of the elastase I promoter. Directed differentiation was achieved by incubation with conditioned media of cultured fetal pancreatic rudiments and adenoviral-mediated co-expression of p48/Ptf1a and Mist1, 2 basic helix-loop-helix transcription factors crucial for normal pancreatic acinar development and differentiation. Results: Selected cells expressed multiple markers of acinar cells, including digestive enzymes and proteins of the secretory pathway, indicating activation of a coordinated differentiation program. The genes coding for digestive enzymes were not regulated as a single module, thus recapitulating what occurs during in vivo pancreatic development. The generated cells displayed transient agonist-induced Ca2+ mobilization and showed a typical response to physiologic concentrations of secretagogues, including enzyme synthesis and secretion. Importantly, these effects did not imply the acquisition of a mixed acinar-ductal phenotype. Conclusions: These studies allow the generation of almost pure acinar-like cells from ES cells, providing a normal cell-based model for the study of the acinar differentiation program in vitro. ; This study was supported by Spanish Ministry of Education and Science Grants (SAF2001-0432 and GEN2001-4748-C05 to A.S.; GEN2001-4748-C01 and SAF2004-01137 to F.X.R. and SAF2006-4973 to M.A.V.), Instituto de Salud Carlos III grants (02/3053 and PI05/2738 to A.S.; and Red HERACLES to M.A.V.), Catalan Government grants (SGR2005 to M.A.V.), and by a National Institutes of Health grant (DK55489 to S.F.K.). A.S. was supported by the Instituto de Salud Carlos III; M.R., F.D. and M. M. were recipients of a Graduate Fellowship from the Ministry of Education and Science, Instituto de Salud Carlos III, and the Catalan Government, respectively.

Inflammatory bowel disease; Faecal microbiota transplantation; Rat model of colitis ; Enfermedad inflamatoria intestinal; Trasplante de microbiota fecal; Modelo de colitis en ratas ; Malaltia inflamatòria intestinal; Trasplantament de microbiota fecal; Model de colitis en rates ; Background: Faecal microbiota transplantation (FMT) is a novel potential therapy for inflammatory bowel diseases, but it is poorly characterised. Methods: We evaluated the performance of the mouse and rat as a pre-clinical model for human microbiota engraftment. We then characterised the effect of a single human stool transfer (HST) on a humanised model of DSS-induced colitis. Colonic and faecal microbial communities were analysed using the 16S rRNA approach and clinical manifestations were assessed in a longitudinal setting. Findings: The microbial community of rats showed greater similarity to that of humans, while the microbiome of mice showed less similarity to that of humans. Moreover, rats captured more human microbial species than mice after a single HST. Using the rat model, we showed that HST compensated faecal dysbiosis by restoring alpha-diversity and by increasing the relative abundance of health-related microbial genera. To some extent, HST also modulated the microbial composition of colonic tissue. These faecal and colonic microbial communities alterations led to a relative restoration of colon length, and a significant decrease in both epithelium damage and disease severity. Remarkably, stopping inflammation by removing DSS before HST caused a faster and greater recovery of both microbiome and clinical manifestation features. Interpretation: Our results indicate that the rat outperforms the mouse as a model for human microbiota engraftment and show that the efficacy of HST can be enhanced when inflammation stimulation is withdrawn. Finally, our findings support a new therapeutic strategy based on the use FMT combined with anti inflammatory drugs. ; Study funded by the Instituto de Salud Carlos III/FEDER (PI17/00614), a government agency. The funder had no role in study design, data collection, data analysis, interpretation or writing of the report.

Angiotensin converting enzyme (ACE) inhibitory peptides have been extensively studied as an alternative to synthetic drugs for the treatment of hypertension. Recent studies have shown that dry-cured ham is an important source of naturally generated bioactive peptides, especially showing ACE inhibitory activity. However, due to their excessive degradation by digestive and brush-border enzymes, it is not clear whether these peptides resist intestinal absorption and reach the blood stream where they may exert their antihypertensive effect. Therefore, dry-cured ham extracts and specific pure peptides naturally generated during the dry-curing process, showing ACE inhibitory activity, have been studied for their stability during transepithelial transport in a Caco-2 cell monolayer. The ACE inhibitory activity of transport samples was assayed, showing the highest values in apical samples at 15 min of incubation. In concentrated basal solutions, ACE inhibition values increased during transport for purified peptides, reaching values close to 70% for AAPLAP and KPVAAP at 60 min of cellular transport. Fragments generated by cellular activity were detected by using tandem mass spectrometry techniques, showing that AAATP, AAPLAP, and KPVAAP were hydrolysed during the transport, although KPVAAP was also absorbed intact. This study highlights the potential of intact dry-cured ham peptides as well as their fragments to be absorbed across the intestinal epithelium and reach the blood stream to exert an antihypertensive action. ; The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement 312090 (BACCHUS). This publication reflects only the author views and the Community is not liable for any use made of the information contained therein. Grant AGL2013-47169-R from MINECO and FEDER funds and the FPI Scholarship BES-2011-046096 from MINECO (Spain) to M.G. are fully acknowledged. The JAEDOC-CSIC postdoctoral contract to L.M. co-funded by the European Social Fund and BOF (Special Research Fund of Ghent University) for their financial support (Project 01B04212) are also acknowledged. ; Peer reviewed

Human Adenoviruses (AdVs) are etiologic agents for respiratory tract, digestive tract, heart, and eye infections. Although most AdV infections are self-resolving, some infections progress to acute respiratory disease with up to 50% mortality, particularly in immunosuppressed people. Except for vaccines for serotypes, 4 and 7, serotypes that are prevalent in the military, no vaccines or therapeutics that specifically prevent or treat AdV infection exist. On the other hand, AdV remains the most common vector system used in gene therapy clinical trials worldwide and several AdV vectors show promise in phase III clinical trials. The majority of AdVs use the coxsackievirus and adenovirus receptor (CAR) as a primary receptor. We have characterized an alternatively spliced eight-exon containing isoform (CAREx8) that localizes at the apical surface of epithelial cells and is responsible for the initiation of apical AdV infection. A cellular scaffold protein named Membrane Associated Guanylate Kinase, WW and PDZ Domain Containing 1 (MAGI-1) directly interacts with and alternatively regulates CAREx8 through the C-terminal PDZ-binding domain. The alternative regulation is due to the interaction with two different domains, namely PDZ1 and PDZ3, within the same molecule (MAGI-1). I hypothesized that cell permeable peptides that target the interaction between MAGI-1 PDZ1 domain and CAREx8 (TAT-PDZ1) would be able to decrease CAREx8 protein levels and prevent AdV infection. On the other hand, peptides that target the interaction between MAGI-1 PDZ3 domain and CAREx8 (TAT-PDZ3) would be able to increase CAREx8 and enhance AdV mediated gene therapy. Decoy peptides that target the assigned domain were synthesized and conjugated to TAT cell permeable peptide to facilitate peptide entry (TAT-PDZ1; TAT-NET1, TAT-E6) or (TAT-PDZ3; TAT-CAREx8-9c, TAT-ESAM). Peptide entry into the polarized epithelia was confirmed by mass spectroscopy and fluorescence microscopy. Treatment with TAT-PDZ1 peptides decreased the cellular levels of CAREx8 and suppressed AdV transduction in MDCK, human airway epithelia (HAE), as well as epithelia from cotton rats, an animal model of AdV pathogenicity. To determine the mechanism of peptide action, CAREx8 localization was tracked by immunofluorescence. Interestingly, TAT-PDZ1 caused nuclear translocation of CAREx8 C-term domain, an effect that was reversed by ADAM17 inhibitor (TIMP3) and ¿-secretase inhibitor (Comp E), implicating the regulated intramembrane proteolysis (RIP) pathway. Immunoprecipitation and direct ligand binding assays showed that ADAM17 interacts specifically with MAGI-1 PDZ2 domain, suggesting that TAT-PDZ1 peptides caused CAREx8 degradation by enhancing the proximity of the substrate (CAREx8) and enzyme (ADAM17). Finally, ADAM17 caused CAREx8 extracellular domain (ECD) shedding that was able to significantly decrease AdV-GFP transduction, indicating a second protective role against AdV entry by the shed ECD of CAREx8. By contrast, TAT-PDZ3 peptides increased the levels of CAREx8 and significantly increased AdV entry and transduction in MDCK, HAE, and cotton rat epithelia. Upon TAT-PDZ3 peptide administration, CAREx8 was localized in vesicular pattern compartments distinct from MAGI-1 and spread throughout the apical trafficking pathway and at the apical surface of the epithelium. Investigation of the trafficking pathway of CAREx8 using Rabs reveal the possibility of CAREx8 is residing within the recycling Endosomal-Golgi pathway. Neither TAT-PDZ1 nor TAT-PDZ3 binding peptides altered epithelium formation, as measured by transepithelial resistance (TER) as well as dextran permeability across the epithelia, indicating the safety of the peptides on epithelial integrity. Moreover, intranasal administration of TAT-PDZ3 peptides increased AdV transduction by 300-500% while TAT-PDZ1 peptides decreased AdV transduction by 80-95% after intrana.

O estudo histológico e morfométrico do intestino delgado de capivaras adultas Hydrochoerus hydrochaeris foi desenvolvido neste trabalho, enfatizando particularidades do duodeno, jejuno e íleo. Foram coletados fragmentos das porções cranial, medial e caudal de cada segmento intestinal, submetidos ao processamento histológico de rotina e corados pelas técnicas de Hematoxilina-Eosina e Alcian Blue-Ácido Periódico de Schiff. O intestino delgado da capivara é semelhante ao da maioria dos mamíferos em relação à sua estrutura histológica, sendo constituído pelas camadas mucosa, submucosa, muscular e serosa. Não houve diferença significativa na espessura dessas camadas entre os segmentos intestinais. Pregas espessas e ramificadas foram encontradas ao longo do intestino delgado, sendo mais desenvolvidas no duodeno. Observaram-se vilosidades digitiformes e com outras formas, além de vilosidades ramificadas, e uma espessa borda em escova. Glândulas de Brünner foram observadas na porção cranial do duodeno, distribuídas na camada submucosa e na área basal da camada mucosa, além de numerosas células caliciformes ao longo do intestino delgado, ambas apresentando glicoconjugados ácidos e neutros. Várias células de defesa foram encontradas no tecido conjuntivo das camadas mucosa e submucosa, principalmente linfócitos difusos ou constituindo nódulos linfóides que se associam para formar as placas de Peyer na porção caudal do íleo. Células de Paneth e células enteroendócrinas também foram detectadas no epitélio intestinal.
Palavras-chave: Roedores. Morfologia. Histometria. Trato Digestivo.

Abstract
The histological and morphometric study of the small intestine of adult capybaras Hydrochoerushydrochaeriswas developed in this work, emphasizing particularities of the duodenum, jejunum, and ileum. Fragments of the cranial, medial, and caudal portions of each intestinal segment were collected, submitted to the routine histological processing, and stained by the techniques of Hematoxylin-Eosin, Alcian Blue, and Periodic Acid Schiff. The small intestine of the capybara, regarding its histological structure, is similar to most mammals, composedofthe mucosal, submucosal, muscular, and serosal layers. There was no significant difference in the thickness of those layers among the intestinal segments. Thick and ramified folds were found along the small intestine, being more developed in the duodenum. Finger-shaped villus and with other forms, besides ramified villus, and a thick brush border were observed. Brünner's glands were seen in the cranial portion of the duodenum, distributed in the submucosal and the basal area of the mucosal layer, as well as numerous goblet cells along the small intestine, both presenting acid, and neutral glycoconjugates. Several defense cells were found in the connective tissue of the mucosal and submucosal layers, mainly lymphocytes, diffuse or forming lymphoid nodules, which aggregate to form Payer´s patches in the caudal portion of the ileum. Paneth´s cells and enteroendocrine cells were also detected in the intestinal epithelium.

Keywords: Digestive Tract. Histometry. Morphology. Rodents.