Contribution à la compréhension et à la prévention de la mort des cellules souches mésenchymateuses après implantation en site ischémique

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

la tension d'oxygène régule les fonctions paracrines des cellules souches mésenchymateuses

International audienceMesenchymal stem cells (MSCs) have captured the attention and research endeavors of the scientific world because of their differentiation potential. However, there is accumulating evidence suggesting that the beneficial effects of MSCs are predominantly due to the multitude of bioactive mediators secreted by these cells. Because the paracrine potential of MSCs is closely related to their microenvironment, the present study investigated and characterized select aspects of the human MSC (hMSC) secretome and assessed its in vitro and in vivo bioactivity as a function of oxygen tension, specifically near anoxia (0.1% O2) and hypoxia (5% O2), conditions that reflect the environment to which MSCs are exposed during MSC-based therapies in vivo. In contrast to supernatant conditioned media (CM) obtained from hMSCs cultured at either 5% or 21% of O2, CM from hMSCs cultured under near anoxia exhibited significantly (p < .05) enhanced chemotactic and proangiogenic properties and a significant (p < .05) decrease in the inflammatory mediator content. An analysis of the hMSC secretome revealed a specific profile under near anoxia: hMSCs increase their paracrine expression of the angiogenic mediators vascular endothelial growth factor (VEGF)-A, VEGF-C, interleukin-8, RANTES, and monocyte chemoattractant protein 1 but significantly decrease expression of several inflammatory/immunomodulatory mediators. These findings provide new evidence that elucidates aspects of great importance for the use of MSCs in regenerative medicine and could contribute to improving the efficacy of such therapies.SIGNIFICANCE:The present study investigated and characterized select aspects of the human mesenchymal stem cell (hMSC) secretome and assessed its in vitro and in vivo biological bioactivity as a function of oxygen tension, specifically near anoxia (0.1% O2) and hypoxia (5% O2), conditions that reflect the environment to which MSCs are exposed during MSC-based therapies in vivo. The present study provided the first evidence of a shift of the hMSC cytokine signature induced by oxygen tension, particularly near anoxia (0.1% O2). Conditioned media obtained from hMSCs cultured under near anoxia exhibited significantly enhanced chemotactic and proangiogenic properties and a significant decrease in the inflammatory mediator content. These findings provide new evidence that elucidates aspects of great importance for the use of MSCs in regenerative medicine, could contribute to improving the efficacy of such therapies, and most importantly highlighted the interest in using conditioned media in therapeutic modalities.Les cellules souches mésenchymateuses (CSM) sont très attractives pour la thérapie cellulaire en raison de leur potentiel de différenciation. Cependant, de nombreuses preuves suggèrent que les effets bénéfiques des CSM sont principalement dus à la multitude de médiateurs bioactifs sécrétés par ces cellules. Parce que le potentiel paracrine des CSM est étroitement lié à leur microenvironnement, la présente étude a examiné et caractérisé certains aspects du sécrétome du CSM humain (CSMh) et évalué sa bioactivité in vitro et in vivo en fonction de la tension en oxygène, en particulier près de l'anoxie. (0,1% O 2) et l’hypoxie (5% O 2), conditions qui reflètent l’environnement auquel les MSC sont exposés au cours de traitements in vivo à base de MSC. Contrairement aux milieux conditionnés (MC) obtenus à partir de CSM cultivées à 5% ou à 21% d'oxygène, les MC provenant de CSM cultivées presque en anoxie présentaient des propriétés chimiotactiques et proangiogéniques renforcées de manière significative (p <0,05) et une diminution significative du contenu en médiateur inflammatoire p<0,05). Une analyse du sécrétome des CSM a révélé un profil spécifique dans l'anoxie proche: les CSM accroissent leur expression paracrine du facteur de croissance endothélial vasculaire (VEGF)-A, VEGF-C, l'interleukine-8, RANTES et la protéine 1 de monocyte, un agent chimioattractant monocytaire mais diminue de façon significative l'expression de plusieurs médiateurs inflammatoires / immomodulateurs. Ces résultats fournissent de nouvelles preuves qui élucident des aspects d'une grande importance pour l'utilisation des CSM en médecine régénérative et pourraient contribuer à améliorer l'efficacité de tels traitements

Bone Regeneration in Sheep Using Acropora Coral, a Natural Resorbable Scaffold, and Autologous Mesenchymal Stem Cells

International audienc

Comparison of Survival and Osteogenic Ability of Human Mesenchymal Stem Cells in Orthotopic and Ectopic Sites in Mice

International audienc

Proangiogenic and Prosurvival Functions of Glucose in Human Mesenchymal Stem Cells upon Transplantation

International audienc

The paracrine effects of human induced pluripotent stem cells promote bone-like structures via the upregulation of BMP expression in a mouse ectopic model

Abstract Use of human induced pluripotent stem cells (h-iPSCs) for bone tissue engineering is most appealing, because h-iPSCs are an inexhaustible source of osteocompetent cells. The present study investigated the contribution of undifferentiated h-iPSCs and elucidated aspects of the underlying mechanism(s) of the involvement of these cells to new bone formation. Implantation of undifferentiated h-iPSCs seeded on coral particles in ectopic sites of mice resulted in expression of osteocalcin and DMP-1, and in mineral content similar to that of the murine bone. The number of the implanted h-iPSCs decreased with time and disappeared by 30 days post-implantation. In contrast, expression of the murine osteogenic genes at day 15 and 30 post-implantation provided, for the first time, evidence that the implanted h-iPSCs affected the observed outcomes via paracrine mechanisms. Supporting evidence was provided because supernatant conditioned media from h-iPSCs (h-iPSC CM), promoted the osteogenic differentiation of human mesenchymal stem cells (h-MSCs) in vitro. Specifically, h-iPSC CM induced upregulation of the BMP-2, BMP-4 and BMP-6 genes, and promoted mineralization of the extracellular matrix. Given the current interest in the use of h-iPSCs for regenerative medicine applications, our study contributes new insights into aspects of the mechanism underlying the bone promoting capability of h-iPSCs

Human Mesenchymal Stem Cell Failure to Adapt to Glucose Shortage and Rapidly Use Intracellular Energy Reserves Through Glycolysis Explains Poor Cell Survival After Implantation

International audienc

Quiescence Preconditioned Human Multipotent Stromal Cells Adopt a Metabolic Profile Favorable for Enhanced Survival under Ischemia

International audienc

A Perfusion Bioreactor for Engineering Bone Constructs: An In Vitro and In Vivo Study

International audienceA perfusion bioreactor, which was designed based on fluidized bed concepts, was validated for the culture of bone constructs of clinically relevant size. For this study, natural coral has been used as three-dimensional scaffolds. This biomaterial is a microporous, biocompatible, osteoconductive, and absorbable scaffold. This perfusion bioreactor provided a stable environment in terms of osmolarity, pH, and, most importantly, oxidative stress. Bone constructs engineered in this system resulted in significantly higher cell proliferation and homogenous cell distribution than those cultured under static conditions. Particularly relevant to the production of bioengineered bone in a clinical setting, custom-made bone constructs (each one with volume up to 30 cm 3) could be produced using a such perfusion bioreactor. Last, but not least, the bone constructs of clinically relevant volume thus produced were shown to be osteogenic when transplanted subcutaneously in sheep