Javiera bravo-alegria university of texas md anderson cancer center (md anderson) researchgate anoxia fetal

Experimental evidence in animal models suggests that misfolded amyloid-b (ab) spreads in disease

Following a prion-like mechanism. Several properties characteristics of infectious prions have been shown

For the induction of ab aggregates. However, a detailed titration of ab misfolding transmissibility and

Estimation of the minimum concentration of biologically active ab seeds able to accelerate pathological

Changes has not yet been performed. In this study, brain extracts from old tg2576 animals were serially

Diluted and intra-cerebrally injected into young subjects from the same transgenic line. Animals were


Sacrificed several months after treatment and brain slices were analyzed for amyloid pathology.Anoxia fetal we observed

That administration of misfolded ab was able to significantly accelerate amyloid deposition in young mice,

Even when the original sample was diluted a million times. The titration curve obtained in this experiment

Was compared to the natural ab load spontaneously accumulated by these mice overtime. Our findings

Suggest that administration of the largest dose of ab seeds led to an acceleration of pathology equivalent to

Over a year. These results show that active ab seeds present in the brain can seed amyloidosis in a titratable

Manner, similarly as observed for infectious prions.

Nitric oxide exerts important regulatory functions in various brain processes. Its synthesis in neurons has been most commonly ascribed to the neuronal nitric oxide synthase (nnos) isoform.Anoxia fetal however, the endothelial isoform (enos), which is significantly associated with caveolae in different cell types, has been implicated in synaptic plasticity and is enriched in the dendrites of CA1 hippocampal neurons. Using high resolution

Microscopy and co-distribution analysis of enos with synaptic and raft proteins, we now show for the first time in primary cortical and hippocampal neuronal cultures, virtually devoid of endothelial cells, that enos is present in neurons and is localized in dendritic spines. Moreover, enos is present in a postsynaptic density-enriched

Biochemical fraction isolated from these neuronal cultures. In addition, qpcr analysis reveals that both the nnos as well as the enos transcripts are present in neuronal cultures.Anoxia fetal moreover, enos inhibition in cortical cells has a negative impact on cell survival after excitotoxic stimulation with N-methyl-D-aspartate (NMDA). Consistent with previous results that indicated nitric oxide production in response to the neurotrophin

BDNF, we could detect enos in immunoprecipitates of the BDNF receptor trkb while nnos could not be detected. Taken together, our results show that enos is located at excitatory synapses where it could represent a source for NO production and thus, the contribution of enos-derived nitric oxide to the regulation of neuronal survival and function deserves further investigations.

Introduction: earlier work by our laboratory and other groups has identified that aging leads to changes in both the immune system and the microbiome.Anoxia fetal the elderly have high mortality and more disability after a stroke, a finding that is recapitulated in murine model. Recently, pro-inflammatory γδ T cells have received increasing attention as a major contributor to gut immune responses. These cells may be a link in the bidirectional communication between the microbiome and the central nervous system. We hypothesize that fecal transplant of aged biome into young animals will enhance inflammation, γδ T cell numbers, and worsen functional recovery after stroke in young mice.

Methods: young C57BL/6 male mice, were randomized and subjected to sham surgery/right middle cerebral artery occlusion (MCAO-60min) followed by reperfusion. All mice received streptomycin treatment at 24h and 48h after MCAO.Anoxia fetal subsequently, mice were gavaged with biome from either young or aged animals at 72 and 96 h post-stroke. Behavioral and functional outcomes were evaluated. Animals were sacrificed 15 days after stroke. Brain atrophy was quantified, and flow cytometry (FACS) and immunohistochemistry was performed on gut tissue and spleen to determine if stroke or the aged biome influence γδ T cells.

Results: young mice transplanted with aged biome take a longer time to regain their pre-stroke body weight. These mice have higher post-stroke hyperactivity compared with mice treated with young biome, as measured by average velocity (p.006) and total distance traveled (p.006) in the open field. Young mice given aged biome had poorer grip strength, as well as a depressive phenotype, when compared with mice transplanted with young biome.Anoxia fetal FACS analysis shows higher levels of γδ T cell in the gut with stroke and with fecal transplant of aged biome (sham vs. Stroke p=0.0443; young vs. Aged biome p=0.0199).

Conclusion: collectively our findings suggests that the gut microbiome plays an important role in post-stroke recovery. Understanding the underlying mechanisms may identify novel therapeutic targets for the treatment of stroke patients.

Natural forms of prion diseases frequently originate by oral (p.O.) infection. However, quantitative information on the gastro-intestinal (GI) absorption of prions (i.E. The bioavailability and subsequent biodistribution) is mostly unknown. The main goal of this study was to evaluate the fate of prions after oral administration, using highly purified radiolabeled prpsc.Anoxia fetal the results showed a bi-phasic reduction of prpsc with time in the GI, except for the ileum and colon which showed sustained increases peaking at 3–6 hr, respectively. Plasma and whole blood ¹²⁵I-prpsc reached maximal levels by 30 min and 3 hr, respectively, and blood levels were constantly higher than plasma. Upon crossing the GI-tract ¹²⁵I-prpsc became associated to blood cells, suggesting that binding to cells decreased the biological clearance of the agent. Size-exclusion chromatography revealed that oligomeric ¹²⁵I-prpsc were transported from the intestinal tract, and protein misfolding cyclic amplification showed that prpsc in organs and blood retained the typical prion self-replicating ability.Anoxia fetal pharmacokinetic analysis found the oral bioavailability of ¹²⁵I-prpsc to be 33.6%. Interestingly, ¹²⁵I-prpsc reached the brain in a quantity equivalent to the minimum amount needed to initiate prion disease. Our findings provide a comprehensive and quantitative study of the fate of prions upon oral infection.

Prions are composed of the misfolded prion protein (prp(sc)) organized in a variety of aggregates. An important question in the prion field has been to determine the identity of functional prp(sc) aggregates. In this study, we used equilibrium sedimentation in sucrose density gradients to separate prp(sc) aggregates from three hamster prion strains (hyper, drowsy, SSLOW) subjected to minimal manipulations.Anoxia fetal we show that prp(sc) aggregates distribute in a wide range of arrangements and the relative proportion of each species depends on the prion strain. We observed a direct correlation between the density of the predominant prp(sc) aggregates and the incubation periods for the strains studied. The relative presence of prp(sc) in fractions of different sucrose densities was indicative of the protein deposits present in the brain as analyzed by histology. Interestingly, no association was found between sensitivity to proteolytic degradation and aggregation profiles. Therefore, the organization of prp molecules in terms of the density of aggregates generated may determine some of the particular strain properties, whereas others are independent from it.Anoxia fetal our findings may contribute to understand the mechanisms of strain variation and the role of prp(sc) aggregates in prion-induced neurodegeneration.

The silences of the archives, the reknown of the story.

The martin guerre affair has been told many times since jean de coras and guillaume lesueur published their stories in 1561. It is in many ways a perfect intrigue with uncanny resemblance, persuasive deception and a surprizing end when the two martin stood face to face, memory to memory, before captivated judges and a guilty feeling bertrande de rols. The historian wanted to go beyond the known story in order to discover the world of the heroes. This research led to disappointments and surprizes as documents were discovered concerning the environment of artigat’s inhabitants and bearing directly on the main characters thanks to notarial contracts.Anoxia fetal along the way, study of the works of coras and lesueur took a new direction. Coming back to the affair a quarter century later did not result in finding new documents (some are perhaps still buried in spanish archives), but by going back over her tracks, the historian could only be struck by the silences of the archives that refuse to reveal their secrets and, at the same time, by the possible openings they suggest, by the intuition that almost invisible threads link here and there characters and events.

A hallmark feature of alzheimer’s disease (AD) is the misfolding, aggregation and brain accumulation of amyloid-β (aβ) and tau proteins. AD is considered as a protein misfolding disorder (pmds), a group of diseases characterized by the misfolding of a native protein into a toxic isoform.Anoxia fetal pmds comprise several pathological conditions, including parkinson’s disease, and transmissible spongiform encephalopathies (tses) or prion diseases. TSEs are so far the only pmds considered as infectious. Recent evidence suggests that misfolding of disease-associated aβ can be transmitted following a prion-like mechanism. However, additional studies need to be done in order to analyze whether aβ has the biological properties of prions. One of these characteristics is that the extent of pathological transmission should directly depend on the amount of aβ aggregated seeds administered, i.E. The material must be titrable in transmission bioassays. The aim of this work was to titrate aβ aggregates in an animal model of AD (tg2576), as well as to find the minimum amount of particles able to accelerate amyloid pathology in vivo.Anoxia fetal

A pool of brain extracts coming from old tg2576 animals was serially diluted. Samples from each dilution were injected into the hippocampus of young tg2576 mice (50 days old). Animals were sacrificed at 285 days old and brain samples were analyzed for amyloid pathology by IHC and ELISA.

As previously shown, administration of misfolded aβ containing brain materials was able to seed the aggregation of endogenous aβ in tg2576 mice. A significant increase was observed for animals injected with the brain dilutions ranging from 10-1 to 10-6. Animals injected with the sample representing the higher dilution (10-7) did not show any significant difference when compared to non-injected controls. Importantly, the burden of aggregates observed in animals injected with the samples bearing the highest concentration of aβ seeds was increased ~400 folds.Anoxia fetal the titration curve obtained in this experiment was compared to the natural aβ load spontaneously accumulated by these mice overtime. Our findings suggest that administration of the largest dose of aβ seeds led to an acceleration of pathology equivalent to several months.

Our findings, together with previously published reports, suggest that some aspects of AD pathology might be transmissible. These results show that active aβ seeds present in the brain of old tg2576 mice can seed brain amyloidosis in a titrable manner, similarly as observed for infectious prions. These results may contribute to understand the mechanisms implicated in the initiation of aβ pathology and therefore be useful to develop new therapeutic strategies.Anoxia fetal

Introduction

Mesenchymal stem cells (mscs) are adult, multipotent, stem cells with immunomodulatory properties. The mechanisms involved in the capacity of mscs to inhibit the proliferation of proinflammatory T lymphocytes, which appear responsible for causing autoimmune disease, have yet to be fully elucidated. One of the underlying mechanisms studied recently is the ability of mscs to generate T regulatory (treg) cells in vitro and in vivo from activated peripheral blood mononuclear cells (PBMC), T-CD4+ and also T-CD8+ cells. In the present work we investigated the capacity of mscs to generate treg cells using T-CD4+ cells induced to differentiate toward the proinflammatory th1 and th17 lineages.Anoxia fetal

Methods

MSCs were obtained from mouse bone marrow and characterized according to their surface antigen expression and their multilineage differentiation potential. CD4+ T cells isolated from mouse spleens were induced to differentiate into th1 or th17 cells and co-cultured with mscs added at day 0, 2 or 4 of the differentiation processes. After six days, CD25, foxp3, IL-17 and IFN-γ expression was assessed by flow cytometry and helios and neuropilin 1 mrna levels were assessed by RT-qpcr. For the functional assays, the ‘conditioned’ subpopulation generated in the presence of mscs was cultured with concanavalin A-activated CD4+ T cells labeled with carboxyfluorescein succinimidyl ester. Finally, we used the encephalomyelitis autoimmune diseases (EAE) mouse model, in which mice were injected with mscs at day 18 and 30 after immunization.Anoxia fetal at day 50, the mice were euthanized and draining lymph nodes were extracted for th1, th17 and treg detection by flow cytometry.

Results

MSCs were able to suppress the proliferation, activation and differentiation of CD4+ T cells induced to differentiate into th1 and th17 cells. This substantial suppressive effect was associated with an increase of the percentage of functional induced CD4+CD25+foxp3+ regulatory T cells and IL-10 secretion. However, using mature th1 or th17 cells our results demonstrated that while mscs suppress the proliferation and phenotype of mature th1 and th17 cells they did not generate treg cells. Finally, we showed that the beneficial effect observed following MSC injection in an EAE mouse model was associated with the suppression of th17 cells and an increase in the percentage of CD4+CD25+foxp3+ T lymphocytes when administrated at early stages of the disease.Anoxia fetal

Conclusions

This study demonstrated that mscs contribute to the generation of an immunosuppressive environment via the inhibition of proinflammatory T cells and the induction of T cells with a regulatory phenotype. Together, these results might have important clinical implications for inflammatory and autoimmune diseases.