Pharmacologically active microcarriers influence VEGF-A effects on mesenchymal stem cell survival

Resistance of transplanted mesenchymal stem cells (MSCs) in post-ischemic heart is limited by their poor vitality. Vascular-endothelial-growth-factor-A (VEGF-A) as such or slowly released by fibronectin-coated pharmacologically-active-microcarriers (FN-PAM-VEGF) could differently affect survival kinases and anti-apoptotic mediator (e.g. Bcl-2). Therefore VEGF-A or FN-PAM-VEGF could differently enhance cell proliferation, and/or resistance to hypoxia/reoxygenation (H/R) of MSCs. To test these hypotheses MSCs were incubated for 6-days with VEGF-A alone or with FN-PAM-VEGF. In addition, MSCs pre-treated for 24-hrs with VEGF-A or FN-PAM-VEGF were subsequently exposed to H/R (72-hrs 3% O(2) and 3-hrs of reoxygenation). Cell-proliferation and post-hypoxic vitality were determined. Kinases were studied at 30-min., 1- and 3-days of treatment. Cell-proliferation increased about twofold (P < 0.01) 6-days after VEGF-A treatment, but by a lesser extent (55% increase) with FN-PAM-VEGF (P < 0.05). While MSC pre-treatment with VEGF-A confirmed cell-proliferation, pre-treatment with FN-PAM-VEGF protected MSCs against H/R. In the early phase of treatments, VEGF-A increased phospho-Akt, phospho-ERK-1/2 and phospho-PKCε compared to the untreated cells or FN-PAM-VEGF. Afterword, kinase phosphorylations were higher with VGEF, except for ERK-1/2, which was similarly increased by both treatments at 3 days. Only FN-PAM-VEGF significantly increased Bcl-2 levels. After H/R, lactate dehydrogenase release and cleaved Caspase-3 levels were mainly reduced by FN-PAM-VEGF. While VEGF-A enhances MSC proliferation in normoxia, FN-PAM-VEGF mainly hampers post-hypoxic MSC death. These different effects underscore the necessity of approaches suited to the various conditions. The use of FN-PAM-VEGF could be considered as a novel approach for enhancing MSC survival and regeneration in hostile environment of post-ischemic tissues

Survival, differentiation, and neuroprotective mechanisms of human stem cells complexed with neurotrophin-3-releasing pharmacologically active microcarriers in an ex vivo model of parkinson’s disease

© AlphaMed Press 2015. Stem cell-based regenerative therapies hold great potential for the treatment of degenerative disorders such as Parkinson’s disease (PD). We recently reported the repair and functional recovery after treatment with human marrow-isolated adult multilineage inducible (MIAMI) cells adhered to neurotrophin-3 (NT3) releasing pharmacologically active microcarriers (PAMs) in hemiparkinsonian rats. In order to comprehend this effect, the goal of the present work was to elucidate the survival, differentiation, and neuroprotective mechanisms of MIAMI cells and human neural stem cells (NSCs), both adhering to NT3-releasing PAMs in an ex vivo organotypic model of nigrostriatal degeneration made from brain sagittal slices. It was shown that PAMs led to a marked increase in MIAMI cell survival and neuronal differentiation when releasing NT3. A significant neuroprotective effect of MIAMI cells adhering to PAMs was also demonstrated. NSCs barely had a neuroprotective effect and differentiated mostly into dopaminergic neuronal cells when adhering to PAM-NT3. Moreover, those cells were able to release dopamine in a sufficient amount to induce a return to baseline levels. Reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay analyses identified vascular endothelial growth factor (VEGF) and stanniocalcin-1 as potential mediators of the neuroprotective effect of MIAMI cells and NSCs, respectively. It was also shown that VEGF locally stimulated tissue vascularization, which might improve graft survival, without excluding a direct neuroprotective effect of VEGF on dopaminergic neurons. These results indicate a prospective interest of human NSC/PAM and MIAMI cell/PAM complexes in tissue engineering for PD.Spanish Ministry of Economy and Competitiveness (Grant SAF2010-17167), a grant from the Comunidad de Madrid (Grant S2011-BMD-2336), and Instituto de Salud Carlos III (Redes Tematicas de Investigacion Cooperativa en Salud RD12/0019/0013) to A.M.S.Peer Reviewe

Transplantation of adipose tissue mesenchymal cells conjugated with VEGF-releasing microcarriers promotes repair in murine myocardial infarction

RATIONALE: Engraftment and survival of transplanted stem or stromal cells in the microenvironment of host tissues may be improved by combining such cells with scaffolds to delay apoptosis and enhance regenerative properties. OBJECTIVES: We examined whether poly(lactic-co-glycolic acid) (PLGA) pharmacologically active microcarriers (PAMs) releasing vascular endothelial growth factor (VEGF) enhance survival, differentiation and angiogenesis of adipose tissue-mesenchymal stromal cells (AT-MSCs). We analyzed the efficacy of transplanted AT-MSCs conjugated with PAMs in a murine model of acute myocardial infarction (AMI). METHODS: We used fibronectin-coated (empty) PAMs or VEGF-releasing PAMs covered with murine AT-MSCs. Twelve month-old C57 mice underwent coronary artery ligation (Lig) to induce AMI, and were randomized into 5 treatment groups: AMI control (saline 20 microL, n=7), AMI followed by intramyocardial injection with AT-MSCs (2.5x105 cells/20 microL, n=5), or concentrated medium from AT-MSCs (CM, 20 microL, n=8), or AT-MSCs (2.5x105 cells/20 microL) conjugated with empty PAMs (n=7), or VEGF-releasing PAMs (n=8). Sham-operated mice (n=7) were used as controls. RESULTS: VEGF-releasing PAMs increased proliferation and angiogenic potential of AT-MSCs, but did not impact their osteogenic or adipogenic differentiation. AT-MSCs conjugated with VEGF-releasing PAMs inhibited apoptosis, decreased fibrosis, increased arteriogenesis and the number of cardiac-resident Ki-67 positive cells, and improved myocardial fractional shortening compared with AT-MSCs alone when transplanted into the infarcted hearts of C57 mice. With the exception of fractional shortening, all such effects of AT-MSCs conjugated with VEGF-PAMs were paralleled by the injection of CM. CONCLUSIONS: AT-MSCs conjugated with VEGF-releasing PAMs exert paracrine effects that may have therapeutic applications

Reparation du systeme cholinergique septo-hippocampique lese: etude et caracterisation du role du 'Nerve Growth Factor' (NGF)

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84774 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Cellules stromales mésenchymateuses et vecteurs polymériques pour l'ingénierie tissulaire du système nerveux central

Les cellules stromales mésenchymateuses (CSM) possèdent de nombreux atouts pour la thérapie cellulaire du cerveau. Nous avons tout d'abord démontré que les CSM ne migraient pas dans le cerveau de rats sains alors qu'elles étaient attirées par une lésion située à grande distance de leur site d'implantation. Nous avons également confirmé que la faible survie et différenciation neuronale des cellules in vivo constituent les obstacles majeurs à la thérapie cellulaire du cerveau. Par conséquent, nous nous sommes ensuite attachés à améliorer le potentiel de différenciation neuronal des CSM avant transplantation, à l'aide d'un pré-traitement en epidermal growth factor (EGF) et basic fibroblast growth factor (bFGF) in vitro. Finalement, nous avons associé des CSM à des vecteurs polymériques, les microcarriers pharmacologiquement actifs (MPA), afin de favoriser la survie, la différenciation neuronale et les capacités de réparation tissulaire des cellules après transplantation. Ces microsphères de PLGA ont ainsi été enrobées d'une surface biomimétique de laminine, après en avoir démontré les bénéfices sur la différenciation neuronale des CSM in vitro. Des CSM ont ensuite été mises en contact avec des MPA enrobées de laminine et libérant une neurotrophine, avant transplantation dans un modèle animal de la maladie de Parkinson. D'importants effets fonctionnels ont été observés par rapport à la greffe de cellules seules, et cette stratégie est la première à démontrer l'intérêt de cellules souches adultes associées à des vecteurs polymériques bioactifs pour protéger le système nerveux central dans le contexte de la maladie de Parkinson.Mesenchymal stromal cells (MSCs) have several advantages for brain cell therapy. We first demonstrated that MSCs do not migrate in healthy rat brains whereas they were attracted by a lesion located far from their implantation site. However, we also confirmed that the poor cell survival and neuronal differentiation are the major obstacles encountered for brain cell therapy. Thus, we then focused on enhancing the neuronal differentiation potential of MSCs before transplantation, using an epidermal growth factor-basic fibroblast growth factor (EGF-bFGF) pre-treatment in vitro. Finally, we associated MSCs to polymeric vectors, the pharmacologically active microcarriers (PAMs), to increase cell survival and neuronal differentiation, and thereby favouring MSC tissue regeneration potential after transplantation. These PLGA microspheres were coated with a biomimetic surface of laminin, after demonstrating the benefits of this molecule on the neuronal differentiation potential of MSCs in vitro. After attachment of MSCs on their surface, neurotrophin releasing, laminin-coated PAMs have been evaluated in a rat model of Parkinson's disease. A significant functional recovery was observed compared to cells grafted without PAMs. This strategy is the first to give the proof of concept for the use of adult stem cells combined to bioactive polymeric vectors to protect the central nervous system in the context of Parkinson's disease.ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF