mitoception-transferring-isolated-human-msc-mitochondria-to

MitoCeption: Transferring Isolated Human MSC Mitochondria to Glioblastoma Stem Cells

Mitochondria play a central role for cell metabolism, energy production and control of apoptosis. Inadequate mitochondrial function has been found ...

Montpellier University

Placental implantation involves highly regulated trophoblast invasion of the endometrial stroma. TGFbeta is a known regulator of this process. This study examines the effect of TGFbeta on extravillous cytotrophoblastic cell (EVCT) migration in cocultures of first-trimester human chorionic villus explants and primary human endometrial fibroblasts. Migration of EVCTs was followed by phase-contrast time-lapse microscopy and was shown to highly depend on the endometrial fibroblast matrix. Interstitial EVCT invasion was also analyzed by confocal microscopy of fluorescently prelabeled trophoblasts and endometrial fibroblasts. As expected, addition of TGFbeta led to inhibition of EVCT invasion of the endometrial cell layer. This inhibition was characterized by formation of compact EVCT stacks at migration fronts and displacement of endometrial fibroblasts. We tested the role of the RhoA/Rho-associated kinase (ROCK) pathway, a TGFbeta-dependent pathway known to regulate cell migration. Interestingly, blocking ROCK with the chemical inhibitor Y27632 had an effect opposite to TGFbeta activation because it promoted superficial EVCT migration on the endometrial cell layer. These data suggest a role for ROCK in the TGFbeta-dependent control of trophoblast migration. Furthermore, they indicate that even though ROCK signaling plays a role in human trophoblast cell invasion, EVCT migration can still occur in the absence of ROCK activity.

Opposite effects of transforming growth factor-beta activation and rho-associated kinase inhibition on human trophoblast migration in a reconstituted placental-endometrial coculture system.

Cell invasion targets specific tissues in physiological placental implantation and pathological metastasis, which raises questions about how this process is controlled. We compare dermis and endometrium capacities to support trophoblast invasion, using matching sets of human primary fibroblasts in a coculture assay with human placental explants. Substituting endometrium, the natural trophoblast target, with dermis dramatically reduces trophoblast interstitial invasion. Our data reveal that endometrium expresses a higher rate of the fibronectin (FN) extra type III domain A+ (EDA+) splicing isoform, which displays stronger matrix incorporation capacity. We demonstrate that the high FN content of the endometrium matrix, and not specifically the EDA domain, supports trophoblast invasion by showing that forced incorporation of plasma FN (EDA-) promotes efficient trophoblast invasion. We further show that the serine/arginine-rich protein serine/arginine-rich splicing factor 1 (SRSF1) is more highly expressed in endometrium and, using RNA interference, that it is involved in the higher EDA exon inclusion rate in endometrium. Our data therefore show a mechanism by which tissues can be distinguished, for their capacity to support invasion, by their different rates of EDA inclusion, linked to their SRSF1 protein levels. In the broader context of cancer pathology, the results suggest that SRSF1 might play a central role not only in the tumor cells, but also in the surrounding stroma.

Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion.

Mitochondrial activity is central to tissue homeostasis. Mitochondria dysfunction constitutes a hallmark of many genetic diseases and plays a key role in tumor progression. The essential role of mitochondria, added to their recently documented capacity to transfer from cell to cell, obviously contributes to their current interest. However, determining the proper role of mitochondria in defined biological contexts was hampered by the lack of suitable experimental tools. We designed a protocol (MitoCeption) to directly and quantitatively transfer mitochondria, isolated from cell type A, to recipient cell type B. We validated and quantified the effective mitochondria transfer by imaging, fluorescence-activated cell sorting (FACS) and mitochondrial DNA analysis. We show that the transfer of minute amounts of mesenchymal stem/stromal cell (MSC) mitochondria to cancer cells, a process otherwise occurring naturally in coculture, results in cancer cell enhanced oxidative phosphorylation (OXPHOS) activity and favors cancer cell proliferation and invasion. The MitoCeption technique, which can be applied to different cell systems, will therefore be a method of choice to analyze the metabolic modifications induced by exogenous mitochondria in host cells.

MitoCeption as a new tool to assess the effects of mesenchymal stem/stromal cell mitochondria on cancer cell metabolism and function.

The aim of this work was to understand whether the nature of breast cancer cells could modify the nature of the dialog of mesenchymal stem cells (MSCs) with cancer cells. By treating MSCs with the conditioned medium of metastatic Estrogen-receptor (ER)-negative MDA-MB-231, or non-metastatic ER-positive MCF-7 breast cancer cells, we observed that a number of chemokines were produced at higher levels by MSCs treated with MDA-MB-231 conditioned medium (CM). MDA-MB-231 cells were able to induce NF-κB signaling in MSC cells. This was shown by the use of a NF-kB chemical inhibitor or an IκB dominant negative mutant, nuclear translocation of p65 and induction of NF-κB signature. Our results suggest that MDA-MB-231 cells exert their effects on MSCs through the secretion of IL-1β, that activates MSCs and induces the same chemokines as the MDA-MB-231CM. In addition, inhibition of IL-1β secretion in the MDA-MB-231 cells reduces the induced production of a panel of chemokines by MSCs, as well the motility of MDA-MB-231 cells. Our data suggest that aggressive breast cancer cells secrete IL-1β, which increases the production of chemokines by MSCs.

IL-1β produced by aggressive breast cancer cells is one of the factors that dictate their interactions with mesenchymal stem cells through chemokine production.

Article	Year
Opposite effects of transforming growth factor-beta activation and rho-associated kinase inhibition on human trophoblast migration in a reconstituted placental-endometrial coculture system. Endocrinology\| PubMed ID: 18499753	2008
Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion. Molecular biology of the cell\| PubMed ID: 23966470	2013
MitoCeption as a new tool to assess the effects of mesenchymal stem/stromal cell mitochondria on cancer cell metabolism and function. Scientific reports\| PubMed ID: 25766410	2015
IL-1β produced by aggressive breast cancer cells is one of the factors that dictate their interactions with mesenchymal stem cells through chemokine production. Oncotarget\| PubMed ID: 26362269	2015

Marie-Luce Vignais

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