Multiple Birthdating Analyses in Adult Neurogenesis: A Line-Up of the Usual Suspects

Analyzing the variation in different subpopulations of newborn neurons is central to the study of adult hippocampal neurogenesis. The acclaimed working hypothesis that different subpopulations of newborn, differentiating neurons could be playing different roles arouses great interest. Therefore, the physiological and quantitative analysis of neuronal subpopulations at different ages is critical to studies of neurogenesis. Such approaches allow cells of different ages to be identified by labeling them according to their probable date of birth. Until very recently, only neurons born at one specific time point could be identified in each experimental animal. However the introduction of different immunohistochemically compatible markers now enables multiple subpopulations of newborn neurons to be analyzed in the same animal as in a line-up, revealing the relationships between these subpopulations in response to specific influences or conditions. This review summarizes the current research carried out using these techniques and outlines some of the key applications

Vitronectin regulates Sonic hedgehog activity during cerebellum development through CREB phosphorylation

12 páginas, 7 figuras.During development of the cerebellum, Sonic hedgehog (SHH) is expressed in migrating and settled Purkinje neurons and is directly responsible for proliferation of granule cell precursors in the external germinal layer. We have previously demonstrated that SHH interacts with vitronectin in the differentiation of spinal motor neurons. Here, we analysed whether similar interactions between SHH and extracellular matrix glycoproteins regulate subsequent steps of granule cell development. Laminins and their integrin receptor subunit alpha6 accumulate in the outer most external germinal layer where proliferation of granule cell precursors is maximal. Consistent with this expression pattern, laminin significantly increases SHH-induced proliferation in primary cultures of cerebellar granule cells. Vitronectin and its integrin receptor subunits alpha(v) are expressed in the inner part of the external germinal layer where granule cell precursors exit the cell cycle and commence differentiation. In cultures, vitronectin is able to overcome SHH-induced proliferation, thus allowing granule cell differentiation. Our studies indicate that the pathway in granule cell precursors responsible for the conversion of a proliferative SHH-mediated response to a differentiation signal depends on CREB. Vitronectin stimulates phosphorylation of cyclic-AMP responsive element-binding protein (CREB), and over-expression of CREB is sufficient to induce granule cell differentiation in the presence of SHH. Taken together, these data suggest that granule neuron differentiation is regulated by the vitronectin-induced phosphorylation of CREB, a critical event that terminates SHH-mediated proliferation and permits the differentiation program to proceed in these cells.This research was supported by grant PM97-0018 to Dr Ignacio Torres Alemán and by grants PM97-0019 and BIO4-CT98-0399 to Dr Paola Bovolenta, in whose laboratories this research was carried out.Peer reviewe

Can Exercise Make You Smarter, Happier, and Have More Neurons? A Hormetic Perspective

Exercise can make you smarter, happier and have more neurons depending on the dose (intensity) of the training program. It is well recognized that exercise protocols induce both positive and negative effects depending on the intensity of the exercise, among other key factors, a process described as a hormetic-like biphasic dose-response. However, no evidences have been reported till very recently about the biphasic response of some of the potential mediators of the exercise-induced actions. This hypothesis and theory will focus on the adult hippocampal neurogenesis (AHN) as a putative physical substrate for hormesis responses to exercise in the context of exercise-induced actions on cognition and mood, and on the molecular pathways which might potentially be mediating these actions.The authors acknowledge the support of CSIC (Spanish Council for Scientific Investigation) and the Ministerio de Economía y Competitividad, Spain (research grant reference BFU2013-48907-R).Peer reviewedPeer Reviewe

Systemic IL-2/anti-IL-2Ab complex combined with sublingual immunotherapy suppresses experimental food allergy in mice through induction of mucosal regulatory T cells

Therapeutic tolerance restoration has been proven to modify food allergy in patients and animal models and although sublingual immunotherapy (SLIT) has showed promise, combined therapy may be necessary to achieve a strong and long‐term tolerance. In this work, we combined SLIT with systemic administration of IL‐2 associated with an anti‐IL‐2 monoclonal antibody (IL‐2/anti‐IL‐2Ab complex or IL‐2C) to reverse the IgE‐mediated experimental allergy. Balb/c mice were sensitized with cholera toxin and milk proteins and orally challenged with allergen to elicit hypersensitivity reactions. Then, allergic mice were treated with a sublingual administration of very low amounts of milk proteins combined with intraperitoneal injection of low doses of IL‐2C. The animals were next re‐exposed to allergens and mucosal as well as systemic immunological parameters were assessed in vivo and in vitro. The treatment reduced serum specific IgE, IL‐5 secretion by spleen cells and increased IL‐10 and TGF‐β in the lamina propria of buccal and duodenal mucosa. We found an augmented frequency of IL‐10‐secreting CD4+CD25+Foxp3+ regulatory T cells (Treg) in the submaxilar lymph nodes and buccal lamina propria. Tregs were sorted, characterized and adoptively transferred to naïve mice, which were subsequently sensitized. No allergy was experienced in these mice and we encouragingly discovered a faster and more efficient tolerance induction with the combined therapy compared with SLIT. The combination of two therapeutic strategies rendered Treg‐mediated tolerance more efficient compared to individual treatments and reversed the established IgE‐mediated food allergy. This approach highlights the ability of IL‐2C to expand Tregs, and it may represent a promising disease‐modifying therapy for managing food allergyInstituto de Estudios Inmunológicos y FisiopatológicosConsejo Nacional de Investigaciones Científicas y Técnica

Systemic IL-2/anti-IL-2Ab complex combined with sublingual immunotherapy suppresses experimental food allergy in mice through induction of mucosal regulatory T cells

Therapeutic tolerance restoration has been proven to modify food allergy in patients and animal models and although sublingual immunotherapy (SLIT) has showed promise, combined therapy may be necessary to achieve a strong and long‐term tolerance. In this work, we combined SLIT with systemic administration of IL‐2 associated with an anti‐IL‐2 monoclonal antibody (IL‐2/anti‐IL‐2Ab complex or IL‐2C) to reverse the IgE‐mediated experimental allergy. Balb/c mice were sensitized with cholera toxin and milk proteins and orally challenged with allergen to elicit hypersensitivity reactions. Then, allergic mice were treated with a sublingual administration of very low amounts of milk proteins combined with intraperitoneal injection of low doses of IL‐2C. The animals were next re‐exposed to allergens and mucosal as well as systemic immunological parameters were assessed in vivo and in vitro. The treatment reduced serum specific IgE, IL‐5 secretion by spleen cells and increased IL‐10 and TGF‐β in the lamina propria of buccal and duodenal mucosa. We found an augmented frequency of IL‐10‐secreting CD4+CD25+Foxp3+ regulatory T cells (Treg) in the submaxilar lymph nodes and buccal lamina propria. Tregs were sorted, characterized and adoptively transferred to naïve mice, which were subsequently sensitized. No allergy was experienced in these mice and we encouragingly discovered a faster and more efficient tolerance induction with the combined therapy compared with SLIT. The combination of two therapeutic strategies rendered Treg‐mediated tolerance more efficient compared to individual treatments and reversed the established IgE‐mediated food allergy. This approach highlights the ability of IL‐2C to expand Tregs, and it may represent a promising disease‐modifying therapy for managing food allergyInstituto de Estudios Inmunológicos y FisiopatológicosConsejo Nacional de Investigaciones Científicas y Técnica

Identification and characterization of microRNAs in Phaseolus vulgaris by high-throughput sequencing

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are endogenously encoded small RNAs that post-transcriptionally regulate gene expression. MiRNAs play essential roles in almost all plant biological processes. Currently, few miRNAs have been identified in the model food legume <it>Phaseolus vulgaris </it>(common bean). Recent advances in next generation sequencing technologies have allowed the identification of conserved and novel miRNAs in many plant species. Here, we used Illumina's sequencing by synthesis (SBS) technology to identify and characterize the miRNA population of <it>Phaseolus vulgaris</it>.</p> <p>Results</p> <p>Small RNA libraries were generated from roots, flowers, leaves, and seedlings of <it>P. vulgaris</it>. Based on similarity to previously reported plant miRNAs,114 miRNAs belonging to 33 conserved miRNA families were identified. Stem-loop precursors and target gene sequences for several conserved common bean miRNAs were determined from publicly available databases. Less conserved miRNA families and species-specific common bean miRNA isoforms were also characterized. Moreover, novel miRNAs based on the small RNAs were found and their potential precursors were predicted. In addition, new target candidates for novel and conserved miRNAs were proposed. Finally, we studied organ-specific miRNA family expression levels through miRNA read frequencies.</p> <p>Conclusions</p> <p>This work represents the first massive-scale RNA sequencing study performed in <it>Phaseolus vulgaris </it>to identify and characterize its miRNA population. It significantly increases the number of miRNAs, precursors, and targets identified in this agronomically important species. The miRNA expression analysis provides a foundation for understanding common bean miRNA organ-specific expression patterns. The present study offers an expanded picture of <it>P. vulgaris </it>miRNAs in relation to those of other legumes.</p

Unravelling Chemical Composition of Agave Spines: News from Agave fourcroydes Lem.

Spines are key plant modifications developed to deal against herbivores; however, its physical structure and chemical composition have been little explored in plant species. Here, we took advantage of high-throughput chromatography to characterize chemical composition of Agave fourcroydes Lem. spines, a species traditionally used for fiber extraction. Analyses of structural carbohydrate showed that spines have lower cellulose content than leaf fibers (52 and 72%, respectively) but contain more than 2-fold the hemicellulose and 1.5-fold pectin. Xylose and galacturonic acid were enriched in spines compared to fibers. The total lignin content in spines was 1.5-fold higher than those found in fibers, with elevated levels of syringyl (S) and guaiacyl (G) subunits but similar S/G ratios within tissues. Metabolomic profiling based on accurate mass spectrometry revealed the presence of phenolic compounds including quercetin, kaempferol, (+)-catechin, and (-)-epicatechin in A. fourcroydes spines, which were also detected in situ in spines tissues and could be implicated in the color of these plants' structures. Abundance of (+)-catechins could also explain proanthocyanidins found in spines. Agave spines may become a plant model to obtain more insights about cellulose and lignin interactions and condensed tannin deposition, which is valuable knowledge for the bioenergy industry and development of naturally dyed fibers, respectively

Impact of operatoŕs experience on peri-procedural outcomes with Watchman FLX: Insights from the FLX-SPA registry

Background: The Watchman FLX is a device upgrade of the Watchman 2.5 that incorporates several design enhancements intended to simplify left atrial appendage occlusion (LAAO) and improve procedural outcomes. This study compares peri-procedural results of LAAO with Watchman FLX (Boston Scientific, Marlborough, Massachusetts) in centers with varying degrees of experience with the Watchman 2.5 and Watchman FLX. Methods: Prospective, multicenter, 'real-world' registry including consecutive patients undergoing LAAO with the Watchman FLX at 26 Spanish sites (FLX-SPA registry). Implanting centers were classified according to the center's prior experience with the Watchman 2.5. A further division of centers according to whether or not they had performed ≤ 10 or > 10Watchman FLX implants was prespecified at the beginning of the study. Procedural outcomes of institutions stratified according to their experience with the Watchman 2.5 and FLX devices were compared. Results: 359 patients [mean age 75.5 (SD8.1), CHA2DS2-VASc 4.4 (SD1.4), HAS-BLED 3.8(SD0.9)] were included. Global success rate was 98.6%, successful LAAO with the first selected device size was achieved in 95.5% patients and the device was implanted at first attempt in 78.6% cases. There were only 9(2.5%) major peri-procedural complications. No differences in efficacy or safety results according to the centeŕs previous experience with Watchman 2.5 and procedural volume with Watchman FLX existed. Conclusions: The Watchman FLX attains high procedural success rates with complete LAA sealing in unselected, real-world patients, along with a low incidence of peri-procedural complications, regardless of operatoŕs experience with its previous device iteration or the number of Watchman FLX devices implanted

Differential Regulation of the Variations Induced by Environmental Richness in Adult Neurogenesis as a Function of Time: A Dual Birthdating Analysis

Adult hippocampal neurogenesis (AHN) augments after environmental enrichment (EE) and it has been related to some of the anxiolytic, antidepressant and neuroprotective effects of EE. Indeed, it has been suggested that EE specifically modulates hippocampal neurogenic cell populations over the course of time. Here we have used dual-birthdating to study two subpopulations of newborn neuron in mice (Mus musculus): those born at the beginning and at the end of enrichment. In this way, we demonstrate that while short-term cell survival is upregulated after an initial 1 week period of enrichment in 2 month old female mice, after long-term enrichment (2 months) neither cell proliferation nor the survival of the younger newly born cell populations are distinguishable from that observed in non-enriched control mice. In addition, we show that the survival of older newborn neurons alone (i.e. those born at the beginning of the enrichment) is higher than in controls, due to the significantly lower levels of cell death. Indeed, these parameters are rapidly adjusted to the sudden cessation of the EE conditions. These findings suggest both an early selective, long-lasting effect of EE on the neurons born in the initial stages of enrichment, and a quick response when the environment again becomes impoverished. Therefore, EE induces differential effects on distinct subpopulations of newborn neurons depending on the age of the immature cells and on the duration of the EE itself. The interaction of these two parameters constitutes a new, specific regulation of these neurogenic populations that might account for the long-term enrichment's behavioral effects