An ectomycorrhizal fungus alters sensitivity to jasmonate, salicylate, gibberellin, and ethylene in host roots.

The phytohormones jasmonate, gibberellin, salicylate, and ethylene regulate an interconnected reprogramming network integrating root development with plant responses against microbes. The establishment of mutualistic ectomycorrhizal symbiosis requires the suppression of plant defense responses against fungi as well as the modification of root architecture and cortical cell wall properties. Here, we investigated the contribution of phytohormones and their crosstalk to the ontogenesis of ectomycorrhizae (ECM) between grey poplar (Populus tremula x alba) roots and the fungus Laccaria bicolor. To obtain the hormonal blueprint of developing ECM, we quantified the concentrations of jasmonates, gibberellins, and salicylate via liquid chromatography-tandem mass spectrometry. Subsequently, we assessed root architecture, mycorrhizal morphology, and gene expression levels (RNA sequencing) in phytohormone-treated poplar lateral roots in the presence or absence of L. bicolor. Salicylic acid accumulated in mid-stage ECM. Exogenous phytohormone treatment affected the fungal colonization rate and/or frequency of Hartig net formation. Colonized lateral roots displayed diminished responsiveness to jasmonate but regulated some genes, implicated in defense and cell wall remodelling, that were specifically differentially expressed after jasmonate treatment. Responses to salicylate, gibberellin, and ethylene were enhanced in ECM. The dynamics of phytohormone accumulation and response suggest that jasmonate, gibberellin, salicylate, and ethylene signalling play multifaceted roles in poplar L. bicolor ectomycorrhizal development

Cell Toxicity Study of Antiseptic Solutions Containing Povidone-Iodine and Hydrogen Peroxide

The increasing incidence of periprosthetic joint infections (PJIs) has led to a growing interest in developing strategies to prevent and treat this severe complication. The surgical site's application of antiseptic solutions to eliminate contaminating bacteria and eradicate the bacterial biofilm has been increasing over time. Even though it has been proven that combining antimicrobials could enhance their activities and help overcome acquired microbial resistance related to the topical use of antibiotics, the toxicity of integrated solutions is not well described. This study aimed to evaluate the cytotoxicity of solutions containing povidone-iodine (PI) and hydrogen peroxide (H2O2), alone or in combination, after 1.3 and 5 min of exposure. Chondrocytes, tenocytes, and fibroblast-like synoviocytes were used for cytotoxicity analysis. Trypan blue stain (0.4% in PBS) was applied to evaluate the dead cells. All solutions tested showed a progressive increase in toxicity as exposure time increased except for PI at 0.3%, which exhibited the lowest toxicity. The combined solutions reported a reduced cellular killing at 3 and 5 min than H2O2 at equal concentrations, similar results to PI solutions

Absence of Rac1 and Rac3 GTPases in the nervous system hinders thymic, splenic and immune-competence development

The nervous system influences organ development by direct innervation and the action of hormones. We recently showed that the specific absence of Rac1 in neurons (Rac1N) in a Rac3-deficient (Rac3KO) background causes motor behavioural defects, epilepsy, and premature mouse death around postnatal day 13. We report here that Rac1N/Rac3KO mice display a progressive loss of immune-competence. Comparative longitudinal analysis of lymphoid organs from control, single Rac1N or Rac3KO, and double Rac1N/Rac3KO mutant animals showed that thymus development is preserved up to postnatal day 9 in all animals, but is impaired in Rac1N/Rac3KO mice at later times. This is evidenced by a drastic reduction in thymic cell numbers. Cell numbers were also reduced in the spleen, leading to splenic tissue disarray. Organ involution occurs in spite of unaltered thymocyte and lymphocyte subset composition, and proper mature T-cell responses to polyclonal stimuli in vitro. Suboptimal thymus innervation by tau-positive neuronal terminals possibly explains the suboptimal thymic output and arrested thymic development, which is accompanied by higher apoptotic rates. Our results support a role for neuronal Rac1 and Rac3 in dictating proper lymphoid organ development, and suggest the existence of lymphoid-extrinsic mechanisms linking neural defects to the loss of immune-competence

Metabolic determinants of the immune modulatory function of neural stem cells.

BACKGROUND: Neural stem cells (NSCs) display tissue trophic and immune modulatory therapeutic activities after transplantation in central nervous system disorders. The intercellular interplay between stem cells and target immune cells is increased in NSCs exposed to inflammatory cues. Here, we hypothesize that inflammatory cytokine signalling leads to metabolic reprogramming of NSCs regulating some of their immune modulatory effects. METHODS: NSC lines were prepared from the subventricular zone (SVZ) of 7-12-week-old mice. Whole secretome-based screening and analysis of intracellular small metabolites was performed in NSCs exposed to cocktails of either Th1-like (IFN-γ, 500 U/ml; TNF-α, 200 U/ml; IL-1β, 100 U/ml) or Th2-like (IL-4, IL-5 and IL-13; 10 ng/ml) inflammatory cytokines for 16 h in vitro. Isotopologues distribution of arginine and downstream metabolites was assessed by liquid chromatography/mass spectrometry in NSCs incubated with U-(13)C6 L-arginine in the presence or absence of Th1 or Th2 cocktails (Th1 NSCs or Th2 NSCs). The expression of arginase I and II was investigated in vitro in Th1 NSCs and Th2 NSCs and in vivo in the SVZ of mice with experimental autoimmune encephalomyelitis, as prototypical model of Th1 cell-driven brain inflammatory disease. The effects of the inflammatory cytokine signalling were studied in NSC-lymph node cells (LNC) co-cultures by flow cytometry-based analysis of cell proliferation following pan-arginase inhibition with N(ω)-hydroxy-nor-arginine (nor-NOHA). RESULTS: Cytokine-primed NSCs showed significantly higher anti-proliferative effect in co-cultures vs. control NSCs. Metabolomic analysis of intracellular metabolites revealed alteration of arginine metabolism and increased extracellular arginase I activity in cytokine-primed NSCs. Arginase inhibition by nor-NOHA partly rescued the anti-proliferative effects of cytokine-primed NSCs. CONCLUSIONS: Our work underlines the use of metabolic profiling as hypothesis-generating tools that helps unravelling how stem cell-mediated mechanisms of tissue restoration become affected by local inflammatory responses. Among different therapeutic candidates, we identify arginase signalling as novel metabolic determinant of the NSC-to-immune system communication.This work has received support from the National Multiple Sclerosis Society (NMSS, partial grants RG-4001-A1), the Italian Multiple Sclerosis Association (AISM, grant 2010/R/31 and grant 2014/PMS/4), the Italian Ministry of Health (GR08-7), the European Research Council (ERC) under the ERC-2010-StG Grant agreement n° 260511-SEM_SEM and the UK Regenerative Medicine Platform Acellular hub (Partnership award RG69889) and core support grant from the Wellcome Trust and MRC to the Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute. LPJ was supported by a Wellcome Trust Research Training Fellowship (RG79423).This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1186/s12974-016-0667-

Inovação na América Latina: temas e metodologias emergentes - Innovation in Latin America: emerging themes and methodologies

Este estudo consiste em uma revisão sistemática da literaturacontemporânea sobre inovação na América Latina. O principal objetivo éencontrar temas recorrentes, criando interceptos de pesquisa para futurasinvestigações a partir da observação de objetos, conteúdos e modelos emascensão. O portfólio bibliográfico, totaliza 47 artigos em língua inglesapublicados entre 2015 e 2017 em periódico, que foram classificadose codificados sistematicamente. Além disto, a análise qualitativa deconteúdo de cada obra está disponível como Apêndice deste artigo.Por meio de uma série de levantamentos comparativos, é traçada umalinha vigente de relevância e contribuição de autores, nacionalidades eperiódicos. Encontrou-se uma preponderância de análises quantitativasde dados secundários, com janelas de tempo estáticas ou curtas (até 3anos), e que abordam temas empresariais ou de políticas de inovação.A amostragem aponta Brasil, Espanha e Colômbia (respectivamente),como as nacionalidades mais representativas na produção acadêmicacontemporânea sobre o recorte proposto

Boosting Interleukin-12 Antitumor Activity and Synergism with Immunotherapy by Targeted Delivery with isoDGR-Tagged Nanogold.

AbstractThe clinical use of interleukin‐12 (IL12), a cytokine endowed with potent immunotherapeutic anticancer activity, is limited by systemic toxicity. The hypothesis is addressed that gold nanoparticles tagged with a tumor‐homing peptide containing isoDGR, an αvβ3‐integrin binding motif, can be exploited for delivering IL12 to tumors and improving its therapeutic index. To this aim, gold nanospheres are functionalized with the head‐to‐tail cyclized‐peptide CGisoDGRG (Iso1) and murine IL12. The resulting nanodrug (Iso1/Au/IL12) is monodispersed, stable, and bifunctional in terms of αvβ3 and IL12‐receptor recognition. Low‐dose Iso1/Au/IL12, equivalent to 18–75 pg of IL12, induces antitumor effects in murine models of fibrosarcomas and mammary adenocarcinomas, with no evidence of toxicity. Equivalent doses of Au/IL12 (a nanodrug lacking Iso1) fail to delay tumor growth, whereas 15 000 pg of free IL12 is necessary to achieve similar effects. Iso1/Au/IL12 significantly increases tumor infiltration by innate immune cells, such as NK and iNKT cells, monocytes, and neutrophils. NK cell depletion completely inhibits its antitumor effects. Low‐dose Iso1/Au/IL12 can also increase the therapeutic efficacy of adoptive T‐cell therapy in mice with autochthonous prostate cancer. These findings indicate that coupling IL12 to isoDGR‐tagged nanogold is a valid strategy for enhancing its therapeutic index and sustaining adoptive T‐cell therapy

The mutualism effector MiSSP7 of Laccaria bicolor alters the interactions between the poplar JAZ6 protein and its associated proteins

Despite the pivotal role of jasmonic acid in the outcome of plant-microorganism interactions, JA-signaling components in roots of perennial trees like western balsam poplar (Populus trichocarpa) are poorly characterized. Here we decipher the poplar-root JA-perception complex centered on PtJAZ6, a co-repressor of JA-signaling targeted by the effector protein MiSSP7 from the ectomycorrhizal basidiomycete Laccaria bicolor during symbiotic development. Through protein–protein interaction studies in yeast we determined the poplar root proteins interacting with PtJAZ6. Moreover, we assessed via yeast triple-hybrid how the mutualistic effector MiSSP7 reshapes the association between PtJAZ6 and its partner proteins. In the absence of the symbiotic effector, PtJAZ6 interacts with the transcription factors PtMYC2s and PtJAM1.1. In addition, PtJAZ6 interacts with it-self and with other Populus JAZ proteins. Finally, MiSSP7 strengthens the binding of PtJAZ6 to PtMYC2.1 and antagonizes PtJAZ6 homo-/heterodimerization. We conclude that a symbiotic effector secreted by a mutualistic fungus may promote the symbiotic interaction through altered dynamics of a JA-signaling-associated protein–protein interaction network, maintaining the repression of PtMYC2.1-regulated genes

IL-17A impairs host tolerance during airway chronic infection by Pseudomonas aeruginosa

Resistance and tolerance mechanisms participate to the interplay between host and pathogens. IL-17-mediated response has been shown to be crucial for host resistance to respiratory infections, whereas its role in host tolerance during chronic airway colonization is still unclear. Here, we investigated whether IL-17-mediated response modulates mechanisms of host tolerance during airways chronic infection by P. aeruginosa. First, we found that IL-17A levels were sustained in mice at both early and advanced stages of P. aeruginosa chronic infection and confirmed these observations in human respiratory samples from cystic fibrosis patients infected by P. aeruginosa. Using IL-17a(-/-) or IL-17ra(-/-) mice, we found that the deficiency of IL-17A/IL-17RA axis was associated with: i) increased incidence of chronic infection and bacterial burden, indicating its role in the host resistance to P. aeruginosa; ii) reduced cytokine levels (KC), tissue innate immune cells and markers of tissue damage (pro-MMP-9, elastin degradation, TGF-β1), proving alteration of host tolerance. Blockade of IL-17A activity by a monoclonal antibody, started when chronic infection is established, did not alter host resistance but increased tolerance. In conclusion, this study identifies IL-17-mediated response as a negative regulator of host tolerance during P. aeruginosa chronic airway infection

Lotus japonicus karrikin receptors display divergent ligand-binding specificities and organ-dependent redundancy

Author summary Plant hormone signaling is crucial for development and for adequate responses to biotic and abiotic environmental conditions. The most recently discovered plant hormone receptor KARRIKIN INSENSITVE 2 (KAI2), binds a small butenolide called karrikin that was discovered in smoke and induces germination of fire-following plants. Several lines of evidence suggest a yet elusive endogenous hormone, which acts as ligand for KAI2. Until its identification, synthetic karrikins or the strigolactone-like molecule GR24 are used to probe the karrikin signaling pathway. While the model plant Arabidopsis contains only one KAI2 gene, several copies are maintained in other species suggesting sub-functionalization. We report that genomes of species in the legume hologalegina clade encode two KAI2 versions. In Lotus japonicus, they diverge in their binding ability to synthetic ligands due to three amino acid changes in their binding pocket, of which two are conserved across legumes and one has independently occurred in several species across the angiosperm phylogeny. Surprisingly, L. japonicus hypocotyls react with developmental responses to two different karrikins (KAR(1), KAR(2)) and a synthetic strigolactone rac-GR24, while root development responds only to KAR(1). This shows that there is not only diversity in ligand-receptor relationships but possibly also organ-specific uptake or metabolism of divergent butenolide molecules. Karrikins (KARs), smoke-derived butenolides, are perceived by the alpha/beta-fold hydrolase KARRIKIN INSENSITIVE2 (KAI2) and thought to mimic endogenous, yet elusive plant hormones tentatively called KAI2-ligands (KLs). The sensitivity to different karrikin types as well as the number of KAI2 paralogs varies among plant species, suggesting diversification and co-evolution of ligand-receptor relationships. We found that the genomes of legumes, comprising a number of important crops with protein-rich, nutritious seed, contain two or more KAI2 copies. We uncover sub-functionalization of the two KAI2 versions in the model legume Lotus japonicus and demonstrate differences in their ability to bind the synthetic ligand GR24(ent-5DS) in vitro and in genetic assays with Lotus japonicus and the heterologous Arabidopsis thaliana background. These differences can be explained by the exchange of a widely conserved phenylalanine in the binding pocket of KAI2a with a tryptophan in KAI2b, which arose independently in KAI2 proteins of several unrelated angiosperms. Furthermore, two polymorphic residues in the binding pocket are conserved across a number of legumes and may contribute to ligand binding preferences. The diversification of KAI2 binding pockets suggests the occurrence of several different KLs acting in non-fire following plants, or an escape from possible antagonistic exogenous molecules. Unexpectedly, L. japonicus responds to diverse synthetic KAI2-ligands in an organ-specific manner. Hypocotyl growth responds to KAR(1), KAR(2) and rac-GR24, while root system development responds only to KAR(1). This differential responsiveness cannot be explained by receptor-ligand preferences alone, because LjKAI2a is sufficient for karrikin responses in the hypocotyl, while LjKAI2a and LjKAI2b operate redundantly in roots. Instead, it likely reflects differences between plant organs in their ability to transport or metabolise the synthetic KLs. Our findings provide new insights into the evolution and diversity of butenolide ligand-receptor relationships, and open novel research avenues into their ecological significance and the mechanisms controlling developmental responses to divergent KLs