Exosomes as a vehicle for alpha-Synuclein toxic species propagation in alpha±-synucleinopathies

alpha-synucleinopathies are a group of neurodegenerative disorders characterized by the presence of abnormally aggregated alpha-synuclein (aS). Recent evidence suggests that the early site of aS aggregation is synapses, where aS seems to play its physiological role. Moreover, aggregated aS is reported to be secreted by cells, suggesting its potential involvement in disease initiation and progression. Considering the nature of neurodegenerative disorders as well as the defined, step-wise spreading of Lewy body pathology in alpha-synucleinopathies, the idea of extracellular aS as a pathogenic prion-like agent is extremely appealing. This research project developed in this frame and it is focused on the propagation of aS toxic species mediated by a particular type of extracellular vesicles, exosomes. To this aim, exosomes containing aS and DOPAL modified aS oligomers were purified by HEK293T cells and we focused on the effect of these vesicles on different cell types. Since, in neurons, exosomes appear to be secreted in a spatially and regulated manner through synapses, we first investigate their effect on primary neuronal culture synapses . Upon incubation, aS containing exosomes and, more significantly, DOPAL-modified aS containing exosomes are delivered to synapses, where they alter proteins amounts, function and neuronal morphology. aS containing exosomes contribute also to neuroinflammation: they mediate increment of IL-1beta cytokine production in mouse immortalized microglia cells. Our results highlight an exosomes-driven toxicity of aS not only to neuronal synapses, but also to microglia, inducing the secretion of IL-1beta. Therefore, aS containing exosomes appear as a vehicle of aS toxicity, which might be interesting not only as a future therapeutic target, but also as a potential biomarker for alpha-synucleinopathies

Leucine-rich repeat kinase 2 positively regulates inflammation and down-regulates NF-κB p50 signaling in cultured microglia cells

7openopenRusso, Isabella; Berti, Giulia; Plotegher, Nicoletta; Bernardo, Greta; Filograna, Roberta; Bubacco, Luigi; Greggio, Elisa*Russo, Isabella; Berti, Giulia; Plotegher, Nicoletta; Bernardo, Greta; Filograna, Roberta; Bubacco, Luigi; Greggio, Elis

DOPAL derived alpha-synuclein oligomers impair synaptic vesicles physiological function

Parkinson's disease is a neurodegenerative disorder characterized by the death of dopaminergic neurons and by accumulation of alpha-synuclein (aS) aggregates in the surviving neurons. The dopamine catabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) is a highly reactive and toxic molecule that leads to aS oligomerization by covalent modifications to lysine residues. Here we show that DOPAL-induced aS oligomer formation in neurons is associated with damage of synaptic vesicles, and with alterations in the synaptic vesicles pools. To investigate the molecular mechanism that leads to synaptic impairment, we first aimed to characterize the biochemical and biophysical properties of the aS-DOPAL oligomers; heterogeneous ensembles of macromolecules able to permeabilise cholesterol-containing lipid membranes. aS-DOPAL oligomers can induce dopamine leak in an in vitro model of synaptic vesicles and in cellular models. The dopamine released, after conversion to DOPAL in the cytoplasm, could trigger a noxious cycle that further fuels the formation of aS-DOPAL oligomers, inducing neurodegeneration

Risk factors for discontinuing oral immunotherapy in children with persistent cow milk allergy

Background: There are no universally accepted criteria for discontinuing milk oral immunotherapy (MOIT) in patients with persistent cow milk allergy (CMA) and little data are available on predictive risk factors for dropping out from oral immunotherapy (OIT), due to allergic reactions or other reasons. Methods: We retrospectively reviewed clinical records of patients with persistent severe CMA undergoing MOIT in a tertiary care center hospital to investigate risk factors associated with discontinuation of OIT. Persistent and severe allergy was defined as the history of systemic reactions and any milk protein-specific IgE level >85 kU/ml. All patients were first admitted for an in-hospital rush phase eventually followed by an at-home dose increase. We evaluated the effect of various factors on two primary outcomes: the highest dose of milk ingested during the in-hospital rush phase and during the home OIT phase. Results: We identified 391 patients, of whom 131 met the inclusion criteria for the retrospective study, 54 females and 77 males. Data of the home OIT phase were available for 104 patients (27%). Regarding the home OIT outcome, an association for having a cow milk avoiding diet was found with reaching a dose below 10 ml during the in-hospital rush phase (relative risks [RR]: 2.33, confidence interval [CI]: 0.85; 6.42), an age above than 10 years from the time of admission (RR: 3.29, CI: 0.85; 12.73), and a higher total number of reactions occurred during the hospitalization (RR: 1.54, CI: 1.02; 2.32), whereas the presence of respiratory reactions with wheezing (RR: 1.93, CI: 0.49; 7.61) and an IM adrenaline use was related to a higher risk of having an OIT still in progress (RR: 5.47, CI: 0.33; 7.73). Conclusions: In this cohort of children with persistent CMA undergoing OIT who presented with respiratory reactions with wheezing, the development of anaphylaxis with the need for IM adrenaline, and age above 10 years were predictors of poor long-term outcome

Peculiarities of Functional Connectivity—including Cross-Modal Patterns—in Professional Karate Athletes: Correlations with Cognitive and Motor Performances

Professional karate is a sport activity requiring both physical and psychological skills that have been associated with a better "global neural efficacy." By means of resting state functional magnetic resonance imaging (rs-fMRI), we investigated the neural correlates of cognitive and kinematic abilities in a group of 14 professional karateka and 14 heathy matched controls. All subjects underwent an extensive cognitive test battery for the identification of individual multidimensional cognitive profile and rs-fMRI scans investigating functional connectivity (FC). Moreover, kinematic performances in athletes were quantified by the Ergo-Mak, an integrated system developed for measuring motor reactivity, strength, and power of athletic gestures. Karateka performed significantly better than controls in the visual search task, an ability linked with increased positive correlations in FC between the right superior parietal lobe and bilateral occipital poles. Kinematic performances of athletic feats were sustained by increased positive correlations between subcortical (cerebellum and left thalamus) and cortical (inferior frontal cortex, superior parietal cortex, superior temporal cortex) regions. An unexpected FC increase between auditory and motor-related areas emerged in karateka, possibly reflecting a cross-modal coupling due to the continuous exposure to either internal or external auditory cues, positing this sensory channel as a possible target for novel training strategies. Results represent a further step in defining brain correlates of "neural efficiency" in these athletes, whose brain can be considered a model of continuous plastic train-related adaptation

Crop rotations sustain cereal yields under a changing climate

Agriculture is facing the complex challenge of satisfying increasing food demands, despite the current and projected negative impacts of climate change on yields. Increasing crop diversity at a national scale has been suggested as an adaptive measure to better cope with negative climate impacts such as increasing temperatures and drought, but there is little evidence to support this hypothesis at the field scale. Using seven long-term experiments across a wide latitudinal gradient in Europe, we showed that growing multiple crop species in a rotation always provided higher yields for both winter and spring cereals (average +860 and +390 kg ha(-1) per year, respectively) compared with a continuous monoculture. In particular, yield gains in diverse rotations were higher in years with high temperatures and scant precipitations, i.e. conditions expected to become more frequent in the future, rendering up to c. 1000 kg ha(-1) per year compared to monocultures. Winter cereals yielded more in diverse rotations immediately after initiation of the experiment and kept this advantage constant over time. For spring cereals, the yield gain increased over time since diversification adoption, arriving to a yearly surplus of c. 500 kg ha(-1) after 50-60 years with still no sign of plateauing. Diversified rotations emerge as a promising way to adapt temperate cropping systems and contribute to food security under a changing climate. However, novel policies need to be implemented and investments made to give means and opportunities for farmers to adopt diversified crop rotations

Observation of Mixed Valence Ru Components in Zn Doped Y2Ru2O7 Pyrochlores

We present a study of Y2 12xZnxRu2O7 pyrochlores as a function of the Zn doping level x. X-ray diffraction measurements show that single-phase samples could be obtained for x < 0.2. Within the allowed range for x, dc conductivity measurements revealed a sizable decrease in resistivity at all the investigated temperatures for Zn doped samples with respect to undoped ones. Neutron diffraction data of the x = 0.2 sample showed that replacing Y3+ by Zn2+ does not result in the formation of oxygen vacancies. X-ray photoemission spectroscopy measurements revealed that part of the Ru ions are in the 5+ oxidation state to balance, in terms of electronic charge, the incorporation of Zn2+. The results give experimental evidence that the heterovalent doping promotes the increase of conductivity in the Y2Ru2O7 pyrochlores, making these systems promising as intermediate temperature solid oxide fuel cell cathodes

Electronic structure and magnetism of strained bcc phases across the fcc to bcc transition in ultrathin Fe films

We investigated the electronic structure of the bcc metastable phases involved in the fcc to bcc transition of Fe. Ultrathin Fe films were grown on a 2-monolayer (ML) Ni/W(110) substrate, where a fcc lattice is stabilized at low Fe coverages and the transition proceeds through the formation of bcc nuclei showing a specific "Kurdjumov-Sachs" orientation with the substrate. A comprehensive description of the electronic structure evolution is achieved by combining spin-resolved UV photoemission spectroscopy and ab initio calculations. According to our results, an exchange-split band structure is observed starting from 2 ML of Fe, concomitant with the formation of ferromagnetic bcc nuclei. Continuous modifications are observed in the spin-resolved photoemission spectra for increasing Fe coverage, especially for what concerns the minority states, possibly indicative of the progressive relaxation of the strained bcc phase starting from the bcc/fcc interface