Culture medium modulates the behaviour of human dental pulp-derived cells: technical note.

International audienc

beta 2-adrenoreceptor stimulation dampens the LPS-induced M1 polarization in pig macrophages

The cross-talk between sympatho-adreno-medullar axis and innate immunity players was mainly studied in rodents. In intensive husbandry, pigs are exposed to multiple stressors inducing repeated releases of catecholamines that bind to adrenoreceptors (AR) on target cells. Among adrenoreceptors, the (beta 2-AR is largely expressed by immune cells including macrophages. We report herein on the effects of catecholamines, through (beta 2-AR stimulation, on pig macrophage functions activated by LPS. beta 2-AR stimulation of porcine macrophages prevented the LPS-induced increase in TINF alpha and IL-8 secretion while increasing IL-10 secretion. In contrast, treatment with a beta 2-agonist had no effect on anti-microbial functions. Lastly, beta 2-AR stimulation of macrophages reduced the expression of genes up regulated by LPS. Altogether, we demonstrated that (beta 2-AR stimulation of porcine macrophages prevented polarization towards a pro-inflammatory phenotype. Since porcine macrophages are a suitable model for human macrophages, our results might be relevant to appreciate catecholamine effects on human macrophages

Dexamethasone stimulates differentiation of odontoblast-like cells in human dental pulp cultures

International audienceRegenerative dental pulp strategies require the identification of precursors able to differentiate into odontoblast-like cells that secrete reparative dentin after injury. Pericytes have the ability to give rise to osteoblasts, chondrocytes, and adipocytes, a feature that has led to the suggestion that odontoblast-like cells could derive from these perivascular cells. In order to gain new insights into this hypothesis, we investigated the effects of dexamethasone (Dex), a synthetic glucocorticoid employed to induce osteogenic differentiation in vitro, in a previously reported model of human dental pulp cultures containing pericytes as identified by their expression of smooth muscle actin (SMA) and their specific ultrastructural morphology. Our data indicated that Dex (10(-8) M) significantly inhibited cell proliferation and markedly reduced the proportion of SMA-positive cells. Conversely, Dex strongly stimulated alkaline phosphatase (ALP) activity and induced the expression of the transcript encoding the major odontoblastic marker, dentin sialophosphoprotein. Nevertheless, parathyroid hormone/parathyroid hormone-related peptide receptor, core-binding factor a1/osf 2, osteonectin, and lipoprotein lipase mRNA levels were not modified by Dex treatment. Dex also increased the proportion of cells expressing STRO-1, a marker of multipotential mesenchymal progenitor cells. These observations indicate that glucocorticoids regulate the commitment of progenitors derived from dental pulp cells to form odontoblast-like cells, while reducing the proportion of SMA-positive cells. These results provide new perspectives in deciphering the cellular and molecular mechanisms leading to reparative dentinogenesis

Myeloid derived suppressor cells recruited by cyclophosphamide in the spleen of non-obese diabetic mouse might participate to diabetes acceleration through their further migration and differentiation into the pancreas

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Diabetes acceleration by cyclophosphamide in the non-obese diabetic mouse is associated with differentiation of immunosuppressive monocytes into immunostimulatory cells

Cyclophosphamide (CTX) was previously shown to induce the recruitment of immunosuppressivemyeloid cells in mouse. In the non-obese diabetic (NOD) mouse, which develops spontaneously type I diabetes, CTX is widely known to accelerate the autoimmune process.Our data demonstrated that CTX actually did mobilize an immunosuppressive myeloid CD11b+ Ly-6G− population in the NOD mouse spleen in addition to a well-identified neutrophil CD11b+ Ly-6G+ population. CD11b+ Ly-6G− cells, in contrast with CD11b+ Ly-6G+ cells, were able to inhibit in vitro mitogen-induced syngeneic T cell proliferation. CD11b+ Ly-6G− cells represented a heterogeneous population mainly made of CD31hi cells and Ly-6C+ monocytes. Only these last ones supported the immunosuppressive in vitro activity and resembled circulating inflammatory monocytes according to flow cytometry, cytology and RT-PCR data.Although CD11b+ Ly-6G− Ly-6C+ cells exhibited immunosuppressive function in vitro, they were not able to control the autoimmune response following CTX injection. Our data show that these CTX-induced immunosuppressive myeloid cells actually behaved as very plastic cells in vitro. Likewise, in the model of prediabetic NOD/SCID mice, CD11b+ Ly-6G− Ly-6C+ were able to differentiate into CD11c+ cells after i.v. injection. Herein, we described a new mechanism by which CTX might induce diabetes acceleration in the NOD mouse. In summary, recruited immunosuppressive cells might participate in the immunopotentiating effect of CTX on the autoimmune response by their further differentiation into immunostimulatory cells

Thérapie cellulaire de la Dystrophie musculaire de Duchenne: Essai préclinique chez le chien myopathe

La dystrophie musculaire de Duchenne (DMD) est une maladie génétique progressive du muscle liéeau chromosome X. Elle est la maladie génétique la plus fréquente chez l’homme. La thérapie cellulairebasée sur l’utilisation de cellules souches somatiques est une voie thérapeutique riche d’intérêt.Nous avons isolé, chez un modèle de chien myopathe, une cellule souche musculaire (MuStem)qui présente les qualités indispensables à une utilisation thérapeutique : forte capacité d’amplification,capacité à fusionner avec les fibres musculaires, renouvellement du contingent de cellules satellites,dispersion dans l’organisme après administration vasculaire, persistance de l’effet à longterme, spectaculaire amélioration clinique des animaux traités. Ces résultats précliniques ouvrent lavoie à un essai thérapeutique chez l’enfant atteint de dystrophie musculaire de Duchenne

Human MuStem cells, a promising therapeutic candidate for muscular dystrophies with immunomodulatory properties

Nowadays, allogeneic cell-based therapeutic approaches for regenerative medecine are limited by graft rejection. To counteract this major deleterious effect, immunosuppressive regimens are developed and given to patients, improving their lifespan but causing in return severe adverse effects. Over the last years, a number of adult stem cell populations including mesenchymal stem cells (MSC) and vessel-associated stem cells were described for the treatment of genetic muscle diseases. Those cells were shown to display immunomodulatory properties by acting, directly or through the secretion of soluble factors, on a large number of immune cell partners (Cossu et al., 2012; English et al., 2013). Duchenne Muscular Dystrophy (DMD) is a degenerative muscle disease characterized notably by an inflammatory component that negatively impacts on muscle regeneration activity. In this context, these original immune features attributed to stem cells could be a great advantage to improve cell engraftment and efficiency. In the laboratory, we have isolated a population of muscle-derived stem cells from healthy dog muscle tissue, called cMuStem cells, and made the proof of concept of their systemic delivery efficiency in the preclinical GRMD canine model of DMD (Rouger et al, 2011; Robriquet et al, 2015). Recently, we managed to isolate the same population from Paravertebralis muscle of 9 to 15-years old patients free of known muscle disease (hMuStem cells). It was defined as a mixed population composed of both myogenic progenitors and mesenchymal perivascular cells, and characterized by a large proliferation rate, an oligopotency as well as an in vivo myogenic regenerative potential. The aim of the study was to determine whether hMuStem cells also exhibit immunomodulatory properties. Interestingly, our preliminary data show the ability of hMuStem cells from different donors to modulate allogeneic T cell proliferation and to secrete various immunomodulatory molecules (prostaglandin-E2, indoleamin-2,3-deoxygenase-1, heme oxygenase-1 and inducible nitric-oxide synthase-1). Our data also suggest that hMuStem cells are able to interact with the complement system by inhibiting complement-mediated lysis of erythrocytes. This effect seems to be mediated by factor H, an alternative inhibitory complement pathway. Overall, our study is critical for the understanding of the interaction between MuStem cells and the immune system, as well as the design of safe and efficient allogeneic stem cell-based therapy for the treatment of muscular dystrophies

Biological markers associated with robustness of piglets at weaning

Biological markers associated with robustness of piglets at weaning. 10. European Symposium of porcine Health Managemen

Caractérisation phénotypique de cellules souches somatiques dérivées du muscle chez le chien

Caractérisation phénotypique de cellules souches somatiques dérivées du muscle chez le chien. 15th Annual Congress of the French Society of Cytometry (AFC

Immunomodulatory properties of human MuStem cells: assessing their impact on adaptive and innate immunity

Several preclinical approaches based on allogeneic stem cell delivery were shown to be attractive for the treatment of genetic muscular dystrophies. Nevertheless, a significant hurdle for their clinical translation is the immune rejection of donor cells. Immunosuppressive regimens are generally used to overcome host immunity and can allow the improvement of graft survival. Nevertheless, they are associated with a number of side effects, limiting their long term use. Recently, some tissue-specific adult stem cell populations were described to exhibit immunomodulatory properties that could increase their ability to engraft in an allogeneic recipient and improve their regenerative potential. We have previously demonstrated that allogeneic muscle-derived delayed adherent stem cells (that we called MuStem cells) are able to phenotypically and clin- ically correct the Duchenne dystrophic canine model (Rouger et al., 2011; Robriquet et al., 2015). Recently, we isolated human MuStem cells and assessed their immunomodulatory potential. We evaluated their ability to inhibit T cell prolif- eration and to modulate the complement pathway. Interest- ingly, our preliminary data showed that human MuStem cells were able to modulate allogeneic T cell proliferation and to express immunomodulatory molecules such as prostaglandin- E2, indoleamin-2,3-deoxygenase-1 and TGFb2. Moreover, MuStem cells were also able to secrete Factor H molecule suggesting a potential effect on the alternate pathway of the complement system. Overall, our study is critical for the un- derstanding of the crosstalk between MuStem cells and the im- mune system, as well as the design of safe and efficient allogeneic stem cell-based therapy for the treatment of muscle dystrophie