Saccharomyces boulardii Improves Intestinal Cell Restitution through Activation of the α2β1 Integrin Collagen Receptor

Intestinal epithelial cell damage is frequently seen in the mucosal lesions of inflammatory bowel diseases such as ulcerative colitis or Crohn's disease. Complete remission of these diseases requires both the cessation of inflammation and the migration of enterocytes to repair the damaged epithelium. Lyophilized Saccharomyces boulardii (Sb, Biocodex) is a nonpathogenic yeast widely used as a therapeutic agent for the treatment and prevention of diarrhea and other gastrointestinal disorders. In this study, we determined whether Sb could accelerate enterocyte migration. Cell migration was determined in Sb force-fed C57BL6J mice and in an in vitro wound model. The impact on α2β1 integrin activity was assessed using adhesion assays and the analysis of α2β1 mediated signaling pathways both in vitro and in vivo. We demonstrated that Sb secretes compounds that enhance the migration of enterocytes independently of cell proliferation. This enhanced migration was associated with the ability of Sb to favor cell-extracellular matrix interaction. Indeed, the yeast activates α2β1 integrin collagen receptors. This leads to an increase in tyrosine phosphorylation of cytoplasmic molecules, including focal adhesion kinase and paxillin, involved in the integrin signaling pathway. These changes are associated with the reorganization of focal adhesion structures. In conclusion Sb secretes motogenic factors that enhance cell restitution through the dynamic regulation of α2β1 integrin activity. This could be of major importance in the development of novel therapies targeting diseases characterized by severe mucosal injury, such as inflammatory and infectious bowel diseases

Dialogue entre les molécules d'adhérence et le récepteur à l'IGF-I lors de la progression des mélanomes

Le mélanome est un cancer en recrudescence depuis 10 ans. Il est devenu de ce fait une préoccupation majeure de santé publique. Au cours de la progression tumorale, l’expression des molécules d’adhérence (intégrines et cadhérines) ainsi que le récepteur à l’IGF de type I (IGF-IR) sont modulées. Notamment, il est observé un « switch des cadhérines » de la E vers la N, une surexpression des intégrines α2 et αv, et de l’IGF-IR. C’est dans cette optique que nous nous sommes intéressés aux dialogues croisés entre les molécules d’adhérence et l’IGF-IR. Dans un premier temps, nous avons mis en évidence un dialogue entre la N-cadhérine et l’intégrine αv lors de la migration des mélanomes. Dans un second temps, nous avons démontré que les dialogues entre l’IGF-IR, l’intégrine α2 et les cadhérines différent selon la nature de la cadhérine incriminée. Ces modifications de dialogues ont un impact important sur la propension migratoire des mélanomes.Cutaneous malignant melanoma is an aggressive melanocyte malignancy that is characterized by early metastasis, bad prognosis, and poor survival. Altered cell-cell adhesion (cadherins), cell-extracellular matrix (integrins) interaction, and IGF type I receptor (IGF-IR) are playing an important role in melanoma progression. In particular, we observed a "cadherins switch" from E to N, and α2- αv-integrins and IGF-IR over-expression. In this optics, we were interested in the crosstalk between adhesion molecules and IGF-IR. First, we brought to light a crosstalk between N-cadherin and αv-integrin during melanoma migration. Secondly, we demonstrated that the dialogues between the IGF-IR, α2-integrin and cadherins are different according to the nature of the cadherin involved. Such modulation in the crosstalk may have an important impact on the migratory inclination of melanomas

Dialogue entre les molécules d'adhérence et le récepteur à l'IGF-I lors de la progression des mélanomes

Le mélanome est un cancer en recrudescence depuis 10 ans. Il est devenu de ce fait une préoccupation majeure de santé publique. Au cours de la progression tumorale, l expression des molécules d adhérence (intégrines et cadhérines) ainsi que le récepteur à l IGF de type I (IGF-IR) sont modulées. Notamment, il est observé un switch des cadhérines de la E vers la N, une surexpression des intégrines a2 et av, et de l IGF-IR. C est dans cette optique que nous nous sommes intéressés aux dialogues croisés entre les molécules d adhérence et l IGF-IR. Dans un premier temps, nous avons mis en évidence un dialogue entre la N-cadhérine et l intégrine av lors de la migration des mélanomes. Dans un second temps, nous avons démontré que les dialogues entre l IGF-IR, l intégrine a2 et les cadhérines différent selon la nature de la cadhérine incriminée. Ces modifications de dialogues ont un impact important sur la propension migratoire des mélanomes.Cutaneous malignant melanoma is an aggressive melanocyte malignancy that is characterized by early metastasis, bad prognosis, and poor survival. Altered cell-cell adhesion (cadherins), cell-extracellular matrix (integrins) interaction, and IGF type I receptor (IGF-IR) are playing an important role in melanoma progression. In particular, we observed a "cadherins switch" from E to N, and a2- av-integrins and IGF-IR over-expression. In this optics, we were interested in the crosstalk between adhesion molecules and IGF-IR. First, we brought to light a crosstalk between N-cadherin and av-integrin during melanoma migration. Secondly, we demonstrated that the dialogues between the IGF-IR, a2-integrin and cadherins are different according to the nature of the cadherin involved. Such modulation in the crosstalk may have an important impact on the migratory inclination of melanomas.AIX-MARSEILLE1-Bib.electronique (130559902) / SudocSudocFranceF

Lebectin increases N-cadherin-mediated adhesion through PI3K/AKT pathway.

International audienceCell adhesion molecules, including cadherins and integrins, play an essential role during tumor progression and represent potential targets for the development of new therapeutic agents. We previously showed that lebectin, a C-type lectin protein (CLP) issued from Macrovipera lebectina snake venom, inhibits integrin-mediated migration of IGR39 melanoma cells. Here we assessed whether lebectin modulates cell-cell adhesion. We demonstrated that lebectin promotes N-cadherin/catenin complex reorganization at cell-cell contacts, inducing a strengthening of intercellular adhesion. This reorganization is associated to phosphorylation of beta-catenin on tyrosine 142 residue. Interestingly, lebectin acts on N-cadherin-mediated cell-cell contacts through PI3K/Akt pathway. This effect could contribute to the blockage of tumor cell migration previously observed

alpha v integrin processing interferes with the cross-talk between alpha v beta 5/beta 6 and alpha 2 beta 1 integrins

International audienceBackground information. Previous studies have reported that cross-talk between integrins may be an important regulator of integrin-ligand binding and subsequent signalling events that control a variety of cell functions in many tissues. We previously demonstrated that alpha v beta 5/beta 6 integrin represses alpha 2 beta 1-dependent cell migration. The alpha v subunits undergo an endoproteolytic cleavage by protein convertases, whose role in tumoral invasion has remained controversial. Results. Inhibition of convertases by the convertase inhibitor alpha 1-PDX (alpha 1-antitrypsin Portland variant), leading to the cell-surface expression of an uncleaved form of the av integrin, stimulated cell migration toward type I collagen. Under convertase inhibition, alpha 2 beta 1 engagement led to enhanced phosphorylation of both FAK (focal adhesion kinase) and MAPK (mitogen-activated protein kinase). This outside-in signalling stimulation was associated with increased levels of activated integrin located in larger than usual focal-adhesion structures and a cell migration that was independent of the PI3K (phosphoinositide 3-kinase)/Akt (also called protein kinase B) pathway. Conclusions. The increase in cell migration observed upon convertases inhibition appears to be due to the up-regulation of beta 1 integrins and to their location in larger focal-adhesion structures. The endoproteolytic cleavage of av subunits is necessary for alpha v beta 5/beta 6 integrin to control alpha 2 beta 1 function and could thus play an essential role in colon cancer cell migration

Deciphering the Crosstalk Between Myeloid-Derived Suppressor Cells and Regulatory T Cells in Pancreatic Ductal Adenocarcinoma

International audiencePancreatic ductal adenocarcinoma (PDAC) is a fatal disease with rising incidence and a remarkable resistance to current therapies. The reasons for this therapeutic failure include the tumor's extensive infiltration by immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). By using light sheet fluorescent microscopy, we identified here direct interactions between these major immunoregulatory cells in PDAC. The in vivo depletion of MDSCs led to a significant reduction in Tregs in the pancreatic tumors. Through videomicroscopy and ex vivo functional assays we have shown that (i) MDSCs are able to induce Treg cells in a cell-cell dependent manner; (ii) Treg cells affect the survival and/or the proliferation of MDSCs. Furthermore, we have observed contacts between MDSCs and Treg cells at different stages of human cancer. Overall our findings suggest that interactions between MDSCs and Treg cells contribute to PDAC immunosuppressive environment

Saccharomyces boulardii CNCM I-745 Restores intestinal Barrier Integrity by Regulation of E-cadherin Recycling

International audienceAlteration in intestinal permeability is the main factor underlying the pathogenesis of many diseases affecting the gut, such as inflammatory bowel disease [IBD]. Characterization of molecules targeting the restoration of intestinal barrier integrity is therefore vital for the development of alternative therapies. The yeast Saccharomyces boulardii CNCM I-745 [Sb], used to prevent and treat antibiotic-associated infectious and functional diarrhea, may have a beneficial effect in the treatment of IBD