40 research outputs found
Practical fixed-time stabilization for discrete-time impulsive switched port-controlled Hamiltonian systems
No full textThis paper is concerned with practical fixed-time (FT) stabilization problem of discretetime impulsive switched port-controlled Hamiltonian systems (DISPCH). First, starting with discrete-time port-controlled Hamiltonian systems, a novel controller is presented to achieve practical FT stability of the obtained closed-loop system. Moreover, in order to well handle the abrupt changes at switch moments in practical switched systems, another novel controller is presented in terms of positive-order Lyapunov functions approach and range dwell time method to make discrete-time impulsive switched port-controlled Hamiltonian system practical FT stable. Ultimately, the validity of proposed methods is illustrated by simulations
Evaluation of blood flow as a route for propagation in experimental synucleinopathy
No full textInternational audienceIn Parkinson's disease, synucleinopathy is hypothesized to spread from the enteric nervous system, via the vagus nerve, to the central nervous system. Recent evidences collected in non-human primates challenge however the hypothesis of a transmission of α-synuclein (α-syn) pathology through the vagus nerve. Would the hypothesis whereby the bloodstream acts as a route for long-distance transmission of pathological α-syn hold true, an inter-individual transmission of synucleinopathy could occur via blood contact. Here, we used a parabiosis approach to join the circulatory systems of wild type and GFP transgenic C57BL/6 J mice, for which one of the partners parabiont received a stereotaxic intranigral injection of patient-derived α-syn aggregates. While the Lewy Body-receiving mice exhibited a loss of dopamine neurons and an increase in nigral S129 phosphorylated α-syn immunoreactivity, their parabiotic bloodstream-sharing partners did not show any trend for a lesion or change in S129 phosphorylated-α-syn levels. Altogether, our study suggests that, in the patient-derived α-synuclein aggregates-injected mouse model and within the selected time frame, the disease is not "transmitted" through the bloodstream
Notch promotes neural lineage entry by pluripotent embryonic stem cells
No full textA central challenge in embryonic stem (ES) cell biology is to understand how to impose direction on primary lineage commitment. In basal culture conditions, the majority of ES cells convert asynchronously into neural cells. However, many cells resist differentiation and others adopt nonneural fates. Mosaic activation of the neural reporter Sox-green fluorescent protein suggests regulation by cell-cell interactions. We detected expression of Notch receptors and ligands in mouse ES cells and investigated the role of this pathway. Genetic manipulation to activate Notch constitutively does not alter the stem cell phenotype. However, upon withdrawal of self-renewal stimuli, differentiation is directed rapidly and exclusively into the neural lineage. Conversely, pharmacological or genetic interference with Notch signalling suppresses the neural fate choice. Notch promotion of neural commitment requires parallel signalling through the fibroblast growth factor receptor. Stromal cells expressing Notch ligand stimulate neural specification of human ES cells, indicating that this is a conserved pathway in pluripotent stem cells. These findings define an unexpected and decisive role for Notch in ES cell fate determination. Limiting activation of endogenous Notch results in heterogeneous lineage commitment. Manipulation of Notch signalling is therefore likely to be a key factor in taking command of ES cell lineage choice
Comparison of the expression and toxicity of AAV2/9 carrying the human A53T α-synuclein gene in presence or absence of WPRE
No full textInternational audienceWoodchuck Hepatitis Virus Post-transcriptional Regulatory Element (WPRE) is thought to enhance transgene expression of target genes delivered by adeno-associated viral (AAV) vectors. This study assessed the protein expression of α-synuclein, phosphorylated α-synuclein at Serine 129, extent of nigrostriatal degeneration as well as subsequent behavioral deficits induced by unilateral intranigral stereotactic injection in male adult C57BL/6J mice of an AAV2/9 expressing A53T human α-synuclein under the control of the synapsin promoter in presence or absence of the WPRE. The presence of WPRE enabled to achieve greater nigrostriatal degeneration and synucleinopathy which was concomitant with worsened forelimb use asymmetry. This work refines a mouse Parkinson's disease model in which anatomo-pathology is related to behavioral deficits
Reduced oligodendrocyte exosome secretion in multiple system atrophy involves SNARE dysfunction
No full textInternational audienceAbstract Transportation of key proteins via extracellular vesicles has been recently implicated in various neurodegenerative disorders, including Parkinson’s disease, as a new mechanism of disease spreading and a new source of biomarkers. Extracellular vesicles likely to be derived from the brain can be isolated from peripheral blood and have been reported to contain higher levels of α-synuclein (α-syn) in Parkinson’s disease patients. However, very little is known about extracellular vesicles in multiple system atrophy, a disease that, like Parkinson’s disease, involves pathological α-syn aggregation, though the process is centred around oligodendrocytes in multiple system atrophy. In this study, a novel immunocapture technology was developed to isolate blood CNPase-positive, oligodendrocyte-derived enriched microvesicles (OEMVs), followed by fluorescent nanoparticle tracking analysis and assessment of α-syn levels contained within the OEMVs. The results demonstrated that the concentrations of OEMVs were significantly lower in multiple system atrophy patients, compared to Parkinson’s disease patients and healthy control subjects. It is also noted that the population of OEMVs involved was mainly in the size range closer to that of exosomes, and that the average α-syn concentrations (per vesicle) contained in these OEMVs were not significantly different among the three groups. The phenomenon of reduced OEMVs was again observed in a transgenic mouse model of multiple system atrophy and in primary oligodendrocyte cultures, and the mechanism involved was likely related, at least in part, to an α-syn-mediated interference in the interaction between syntaxin 4 and VAMP2, leading to the dysfunction of the SNARE complex. These results suggest that reduced OEMVs could be an important mechanism related to pathological α-syn aggregation in oligodendrocytes, and the OEMVs found in peripheral blood could be further explored for their potential as multiple system atrophy biomarkers
Mechanisms of motor and non-motor complications in experimental parkinsonism
No full textParkinson’s disease (PD), one of the most common neurodegenerative disorders, is classically characterized by the progressive loss of midbrain dopaminergic neurons and by the emergence of cardinal motor symptoms including rigidity, tremor and bradykinesia. PD treatment relies on pharmacological dopamine replacement, which is the most effective therapy to alleviate motor symptoms. However, the use of L-Dopa and dopamine receptor agonists is associated with the development of motor and non-motor complications, such as dyskinesia and neuropsychiatric disorders, which can be even more debilitating than the cardinal symptoms of PD and represent a major limitation to its management. Utilizing experimental models of PD, the work presented in this thesis investigates the underlying mechanisms involved in these treatment-related complications.In Paper I we examined changes in autophagy associated with L-Dopa-induced dyskinesia (LID), which consists of dystonic and choreic abnormal involuntary movements tending to occur within a few years from the beginning of L-Dopa treatment. We found that LID is associated with dopamine D1 receptor (D1R)-mediated accumulation of the autophagy- specific substrate p62, a marker of autophagy deficiency. Inhibition of the mammalian target of rapamycin complex 1 with rapamycin counteracted the impairment of autophagy produced by L-Dopa, and reduced dyskinesia, suggesting that autophagy-promoting agents may represent a novel pharmacological approach to the treatment of dyskinesia. In Paper II we examined the ability of pre- and post-surgical interventions to reduce the mortality observed in a bilateral 6-hydroxydopamine mouse model reproducing non-motor symptoms of PD. We showed that the survival rate of male and female mice subjected to this lesion differs significantly, with higher mortality among males, and provided a protocol of enhanced care, which nearly eliminates animal loss. The same model was utilized in Paper III to recapitulate features of dopamine dysregulation syndrome, a non-motor complication in PD patients associated with pathological overconsumption of dopaminergic medications, far beyond that necessary to correct motor disabilities. We found that L-Dopa acquires rewarding properties in dopamine-depleted mice and this effect was mediated by abnormal D1R transmission in the dorsal striatum. We identified ΔFosB as a potential target to counteract this condition.Overall, the work presented in this thesis offers a new perspective on underlying, and potentially common, mechanisms involved in motor and non-motor complications induced by dopamine replacement therapy. These studies also reveal the importance of employing appropriate experimental models of PD to identify novel targets for therapeutic interventions.List of scientific papersI. Feyder, M., Plewnia, C. (co-first author), Lieberman, O. J., Spigolon, G., Piccin, A., Urbina, L., Dehay, B., Li, Q., Nilsson, P., Altun, M., Santini, E., Sulzer, D., Bezard, E., Borgkvist, A., & Fisone, G. Involvement of Autophagy in Levodopa-Induced Dyskinesia. Movement Disorders. 2021, 36(5):1137- 1146. https://doi.org/10.1002/mds.28480 II. Masini, D., Plewnia, C., Bertho, M., Scalbert, N., Caggiano, V., Fisone, G. A Guide to the Generation of a 6-Hydroxydopamine Mouse Model of Parkinson's Disease for the Study of Non-Motor Symptoms. Biomedicines. 2021, 9(6):598. https://doi.org/10.3390/biomedicines9060598 III. Plewnia, C., Masini, D., Fisone, G. Rewarding properties of L-Dopa in experimental parkinsonism are linked to dysregulated dopamine D1 receptor transmission. [Manuscript]</p
Applications of RFID in the pharmaceutical supply chain
No full textL’obiettivo di questa tesi è principalmente quello di mostrare le possibili applicazioni della tecnologia RFID (Radio Frequency Identification) all’interno della supply chain farmaceutica, cercando di comprendere il campo di applicazione di questa tecnologia in un’industria così altamente regolata e complessa come quella farmaceutica.
La tesi è organizzata in tre sezioni; nel primo capitolo si trattano i principi alla base della tecnologia RFID e l’attuale stato dell’arte nella standardizzazione della banda di frequenza utilizzata e nell’hardware. In questa sezione sono poi mostrate le principali applicazioni e nella parte finale i problemi affrontati da un’azienda nell’applicare l’RFID al proprio business.
Il secondo capitolo descrive le parti coinvolte nell’industria farmaceutica, dal produttore al consumatore finale, poi esamina le caratteristiche essenziali della supply chain farmaceutica e gli aspetti chiave e le criticità da affrontare in questo campo per essere efficiente e per consegnare il prodotto al cliente in maniera sicura e consistente.
Infine nell’ultima sezione i due argomenti centrali sono fusi assieme, cercando di esaminare come la tecnologia RFID sia in grado di risolvere i problemi affrontati da tale industria.
Il lavoro non vuole mostrare la tecnologia RFID come una panacea di tutte le problematiche presentate in questa industria, ma vuole cercare di colmare il gap presente in letteratura riguardo le possibili applicazioni di questa tecnologia nell’industria specificata
Insights into molecular mechanisms of disease in Neurodegeneration with Brain Iron Accumulation; unifying theories.
No full textNeurodegeneration with brain iron accumulation (NBIA) is a group of disorders characterised by dystonia, parkinsonism and spasticity. Iron accumulates in the basal ganglia and may be accompanied by Lewy bodies, axonal swellings and hyperphosphorylated tau depending on NBIA subtype. Mutations in 10 genes have been associated with NBIA that include Ceruloplasmin (Cp) and Ferritin Light Chain (FTL), both directly involved in iron homeostasis, as well as Pantothenate Kinase 2 (PANK2), Phospholipase A2 group 6 (PLA2G6), Fatty acid hydroxylase 2 (FA2H), Coenzyme A synthase (COASY), C19orf12, WDR45 and DCAF17 (C2orf37). These genes are involved in seemingly unrelated cellular pathways, such as lipid metabolism, Coenzyme A synthesis and autophagy. A greater understanding of the cellular pathways that link these genes and the disease mechanisms leading to iron dyshomeostasis is needed. Additionally, the major overlap seen between NBIA and more common neurodegenerative diseases may highlight conserved disease processes. In this review, we will discuss clinical and pathological findings for each NBIA-related gene, discuss proposed disease mechanisms such as mitochondrial health, oxidative damage, autophagy/mitophagy and iron homeostasis and speculate potential overlap between NBIA subtypes
Role of Robo1 receptor in semaphorin signalling system and cortical interneuron migration
No full textEn route to the cerebral cortex, interneurons encounter the developing striatum and avoid
it. It has been shown that these cells express neuropilin (Nrp) as well as PlexinA
receptors, which allow these cells to respond to Sema3A and Sema3F chemorepulsive
cues expressed in the developing striatum and as consequence they migrate around it and
into their proper tangential migratory paths. Robo proteins (receptors for the
chemorepulsive family of ligands Slit) have also been observed in cortical interneurons,
and they are thought to modulate the morphology of migrating interneurons as well as to
play a role in their migration.
In the present work, I found that Robo1, but not Robo2 or Slit1/Slit2, deficient
(Robo1-/-) mice contain a significant number of cortical interneurons migrating aberrantly
through their developing striatum. In vitro experiments showed that dissociated cells
taken from the medial ganglionic eminence (MGE, major source of cortical interneurons)
of Robo1-/- mice do not respond to either Sema3A or Sema3F induced chemorepulsion.
Moreover, I observed significant down regulation of Nrp and PlexinA receptors, as well
as reduced levels of Sema3F expression and of some intracellular effectors activated by
Sema3A and Sema3F in Robo1-/- cortical interneurons. Using a cell line as an in vitro
model, I confirmed that perturbation of Robo1 signalling results in loss of responsiveness
to Sema3A and Sema3F, as well as down regulation of their receptors. Additionally, I
found that Robo1 can bind directly to Nrp and PlexinA proteins.
Taken together, the data presented here suggest a novel role for Robo1 receptor in
controlling the expression of distinct components of the class 3 semaphorin signalling
system and thus, the migration of cortical interneurons. They also suggest that the
migration of cortical interneurons around the striatum might result from the collaborative
effort of Robo1receptors and the class 3 semaphorin signalling system
