Effects of Human Alpha-Synuclein A53T-A30P Mutations on SVZ and Local Olfactory Bulb Cell Proliferation in a Transgenic Rat Model of Parkinson Disease

A transgenic Sprague Dawley rat bearing the A30P and A53T α-synuclein (α-syn) human mutations under the control of the tyrosine hydroxylase promoter was generated in order to get a better understanding of the role of the human α-syn mutations on the neuropathological events involved in the progression of the Parkinson's disease (PD). This rat displayed olfactory deficits in the absence of motor impairments as observed in most early PD cases. In order to investigate the role of the mutated α-syn on cell proliferation, we focused on the subventricular zone (SVZ) and the olfactory bulbs (OB) as a change of the proliferation could affect OB function. The effect on OB dopaminergic innervation was investigated. The human α-syn co-localized in TH-positive OB neurons. No human α-syn was visualized in the SVZ. A significant increase in resident cell proliferation in the glomerular but not in the granular layers of the OB and in the SVZ was observed. TH innervation was significantly increased within the glomerular layer without an increase in the size of the glomeruli. Our rat could be a good model to investigate the role of human mutated α-syn on the development of olfactory deficits

Distinct Roles of Bcl-2 and Bcl-Xl in the Apoptosis of Human Bone Marrow Mesenchymal Stem Cells during Differentiation

Background: Adult mesenchymal stem cells (MSCs) can be maintained over extended periods of time before activation and differentiation. Little is known about the programs that sustain the survival of these cells. Principal Findings: Undifferentiated adult human MSCs (hMSCs) did not undergo apoptosis in response to different cell death inducers. Conversely, the same inducers can readily induce apoptosis when hMSCs are engaged in the early stages of differentiation. The survival of undifferentiated cells is linked to the expression of Bcl-Xl and Bcl-2 in completely opposite ways. Bcl-Xl is expressed at similar levels in undifferentiated and differentiated hMSCs while Bcl-2 is expressed only in differentiated cells. In undifferentiated hMSCs, the down-regulation of Bcl-Xl is associated with an increased sensitivity to apoptosis while the ectopic expression of Bcl-2 induced apoptosis. This apoptosis is linked to the presence of cytoplasmic Nur 77 in undifferentiated hMSCs. Significance: In hMSCs, the expression of Bcl-2 depends on cellular differentiation and can be either pro- or anti-apoptotic. Bcl-Xl, on the other hand, exhibits an anti-apoptotic activity under all conditions

Effet neuro-anatomiques de l'alcoolisation chronique au niveau de structures cerebrales impliquees dans la memoire. Etude d'un modele animal

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 83110 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Étude de la transdifférenciation nerveuse des cellules souches mésenchymateuses (application à la thérapie cellulaire restauratrice dans un modèle animal de la chorée de Huntington)

Les cellules souches adulte mésenchymateuses (MSCs) se différencient en cellules des lignées mésodermique et neuro-ectodermique. L utilisation de MSCs comme source de cellules pour une thérapie cellulaire restauratrice est envisageable. Nous avons entrepris la caractérisation ainsi que la transdifférenciation des MSCs in vitro en cellules nerveuses ainsi que leur transplantation dans le striatum d un rat intoxiqué au 3NP, modèle de la maladie de Huntington. Elle entraîne une dégénérescence des neurones GABAergiques du striatum. Les MSCs, une fois transformées en neurones GABAergiques, pourraient permettre une restauration de la fonction perdue. La réponse inflammatoire à la greffe de MSCs (Rat, Homme) a été étudiée. La transdifférenciation des MSCs de rat in vitro en cellules nerveuses est difficile et dépend des conditions de culture. Après transplantation, aucune transdifférenciation n a été observée mais des effets bénéfiques moteurs de la greffe sont notés. Cette récupération fonctionnelle serait due à la libération au niveau du striatum de facteurs trophiques et/ou stabilisateurs de la matrice extracellulaire par les MSCs. L étude de la réponse immunitaire du cerveau après allo-transplantation ou xéno-transplantation montre l absence de rejet à 90 jours. Ainsi un traitement immunosuppresseur ne serait pas nécessaire en cas de greffe de MSCs d une autre espèce. En conclusion, dans le cas de maladies neurodégénératives, les MSCs pourraient être une source cellulaire prometteuse pour une thérapie restauratrice. Leur mode d action reposerait plutôt sur des propriétés hypoimmunogènique et productrice de facteurs trophiques que sur une transdifférenciation nerveuse.Mesenchymal Stem Cells (MSCs) differentiate in cells from mesodermic and neuro-ectodermic lineages. MSCs as source of cells for restaurative cells therapy seems appropriate. On one hand, we characterized in vitro and studied MSCs transdifferentiation into nerve cells. On the other hand, MSCs were transplanted into the striatum of a 3NP-rat model of Huntington s disease. This disease induces striatal GABAergic neuronal loss. Once MSCs transdifferentiated into GABAergic neurons they could, re-instate the lost function. The inflammatory response to Human or Rat MSC transplants was also investigated. In vitro, MSC transdifferentiation into neurons is difficult and depends on the culture conditions. After transplantation, no MSC transdifferentiation was observed but beneficial effects of the transplant were noticed. This recovery of function is certainly induced by the striatal release of trophic factors and/or extra-cellular matrix components by the MSCs. The inflammatory investigation performed after allo- or xeno-transplantation showed the absence of rejection after 90 days. Therefore an immuno-suppresive treatment would not be necessary for xenogeneic MSC transplantation. To conclude, MSCs could be a promissing cellular source as a treatment in neurodegenerative diseases. Rather than their transdifferentiative properties, their hypoimmunogenic capacity as well as their ability to produce trophic factors are of great interest.NANTES-BU Sciences (441092104) / SudocSudocFranceF

Le disque intervertébral lombal : du développement embryonnaire à la dégénérescence

International audienceLumbar intervertebral discs (IVD) are highly prone to degenerate as early as the skeletal maturity is achieved. This degeneration could explain about 40% of the low back pain cases in humans. Despite the efficiency of pain-relieving treatments, the scientific community seeks to develop innovative therapeutic approaches to limit the use of invasive surgical procedures (spine fusion and arthroplasty). As a prerequisite to the development of these therapeutic strategies, we first have to improve our fundamental knowledge on IVD physiopathology. Recently, several studies have demonstrated that the phenotype of Nucleus pulposus (NP) cells was singular and quite distinct from that of articular chondrocytes. In parallel, recent studies dealing with NP cell development and origin as well as their role in intervertebral tissue homesotasis allowed to gain new insights into the complex mechanisms governing disc degeneration. This review summarizes the actual knowledge on IVD physiology and on the complex cell-mediated processes of IVD degeneration that has recently led the scientific community to explore new biotherapeutic strategies.Les disques intervertébraux (DIV) lombaires sont fortement sujets à une dégénérescence tissulaire dès l’âge de la maturité squelettique. Cette dégénérescence serait à l’origine de 40 % des cas de lombalgie chez l’homme. Malgré des traitements aujourd’hui efficaces contre la douleur, la communauté scientifique cherche à développer de nouvelles approches thérapeutiques afin d’éviter le recours aux arthrodèses ou prothèses discales. Cependant, le développement de ces nouvelles approches nécessite l’approfondissement de nos connaissances fondamentales relatives à la physiopathologie discale. Récemment, des études ont démontré que les cellules du Nucleus pulposus (NP) présentaient un phénotype distinct de celui des chondrocytes articulaires. Parallèlement à ces travaux, des études sur l’origine embryonnaire des cellules du NP ainsi que sur la régulation de l’homéostasie du tissu discal ont permis d’élucider certains mécanismes physiopathologiques. Cette revue résume l’avancée des connaissances relatives à la physiologie du DIV ainsi que les mécanismes mis en place lors de la dégénérescence, permettant ainsi d’envisager de nouvelles stratégies thérapeutiques

The lumbar intervertebral disc: From embryonic development to degeneration

International audienceLumbar intervertebral discs (IVDs) are prone to degeneration upon skeletal maturity. In fact, this process could explain approximately 40% of the cases of low back pain in humans. Despite the efficiency of pain-relieving treatments, the scientific community seeks to develop innovative therapeutic approaches that might limit the use of invasive surgical procedures (e.g., spine fusion and arthroplasty). As a prerequisite to the development of these strategies, we must improve our fundamental knowledge regarding IVD path-ophysiology. Recently, several studies have demonstrated that there is a singular phenotype associated with Nucleus pulposus (NP) cells, which is distinct from that of articular chondrocytes. In parallel, recent studies concerning the origin and development of NP cells, as well as their role in intervertebral tissue homeostasis, have yielded new insights into the complex mechanisms involved in disc degeneration. This review summarizes our current understanding of IVD physiology and the complex cell-mediated processes that contribute to IVD degeneration. Collectively, these recent advances could inspire the scientific community to explore new biotherapeutic strategies

La médecine régénératrice du disque intervertébral : panacée ou illusion ?

International audienceRecent improvements of our understanding of the physiopathological processes of disc degeneration has made possible to consider with interest the regenerative medicine strategies to restore the intervertebral disc (IVD) function. These strategies include cell therapy and tissue engineering that could repair disc integrity by appropriate cells associated or not with a scaffolding biomaterials. Several options can be considered concerning cell types but also biomaterials. Studies in animal and human seem to confirm the feasibility of such an approach. However, unresolved issues remain including cell and biomaterial types to restore a functional nucleopulpogenic extracellular matrix (ECM). To date, stem cells (MSC and induced pluripotent stem cells iPS) and hydrogel family are well acknowledged as the ideal candidates regarding their ability to differentiate into an appropriate cell type and their hyperhydration composition similar to that of intervertebral disc ECM, respectively. Future work should allow to consider regenerative medicine as a breakthrough innovation in the management of low back pain patients. After a brief reminder of the general principles of regenerative medicine and its relevance to treat degenerative disc disease, cell therapy and tissue engineering are discussed. A state of the art is then given before discussing the remaining challenges prior to the transposition to humans.L’amélioration récente de notre compréhension des processus physiopathologiques de la dégénérescence discale permet d’envisager aujourd’hui le développement de stratégies de médecine régénératrice. Il s’agit notamment de la thérapie cellulaire et de l’ingénierie tissulaire qui ont pour objectif la restauration de la fonction discale par un apport de cellules associées ou non à un biomatériau. Différentes options peuvent être envisagées que ce soit au niveau du type cellulaire mais également au niveau du biomatériau utilisé. Les travaux menés chez l’animal et chez l’homme semblent confirmer la faisabilité d’une telle approche. Il reste cependant des questions en suspens, notamment le choix des cellules et du biomatériau adaptés à la restauration fonctionnelle de la matrice extracellulaire (MEC) discale. D’ores et déjà, les cellules souches (cellules stromales mésenchymateuses [CSM] adultes et cellules souches pluripotentes induites [iPS]) et la famille des hydrogels sont reconnus comme des candidats privilégiés au regard respectivement de leur capacité de différenciation en différents types cellulaires et de leur composition hyperhydratée rappelant celle de la MEC du disque intervertébral. Les futurs travaux devraient permettre de positionner la médecine régénératrice comme une innovation de rupture dans la prise en charge des patients lombalgiques. Après un bref rappel des principes de la médecine régénératrice et de son intérêt pour traiter la dégénérescence discale, les approches de thérapie cellulaire et d’ingénierie tissulaire sont discutées. Un état de l’art est ensuite réalisé puis un point sur les derniers défis à relever avant la transposition à l’homme est abordé

Intervertebral disc regeneration: a great challenge for tissue engineers

International audienceno abstrac

Desmin-lacZ transgene expression and regeneration within skeletal muscle transplants.

The purpose of this study was to investigate the initiation and time course of the regeneration process in fragments of skeletal muscle transplants as a function of muscle tissue age at implantation. The appearance of desmin occurs at the very beginning of myogenesis. The transgenic desmin nls lacZ mice used in the study bear a transgene in which the 1 kb DNA 5' regulatory sequence of the desmin gene is linked to a reporter gene coding for Escherichia coli beta-galactosidase. The desmin lacZ transgene labels muscle cells in which the desmin synthesis programme has commenced. We implanted pectoralis muscle fragments from fetal transgenic embryos and mature and old transgenic mice into mature non-transgenic mice. Early events of myogenesis occurring during regeneration started sooner in transplants from 4-month-old (day 3 post-implantation) muscle than in those from 24-month-old (day 5-6 post-implantation) muscle, and they lasted longer in those from young (day 17 post-implantation) than in those from old (day 14 post-implantation) muscle fragments. In adult muscle, transgene activation proceeded from the periphery toward the centre of the transplant. In transplants from fetal 18-day-old pectoralis, myotubes with transgene activity were observed from day 1 to day 19. Desmin immunoreactivity, which appeared about one day after transgene activation, was followed by myosin expression. In adult transplants, the continuity of laminin labelling was disrupted around degenerative fibres, illustrating alteration of the extracellular matrix. Our data suggest that satellite cells from old muscle tissue have lower proliferative capacity and/or less access to trophic substances released by the host (damaged fibres, vascularization) than those from fetal or young adult muscle