Cytoplasm and organelle transfer between mesenchymal multipotent stromal cells and renal tubular cells in co-culture.
ABSTRACT Cell-to-cell interactions of human mesenchymal multipotent stromal cells (MMSC) and rat renal tubular cells (RTC) were explored under conditions of co-cultivation. We observed formation of different types of intercellular contacts, including so called tunneling nanotubes. These contacts were shown to be able to provide transfer of cell's contents, including organelles. We documented intercellular exchange with fluorescent probes specific to cytosol, plasmalemma and mitochondria. Initial transport of cellular components was revealed after 3 h of co-culturing, and occurred in two directions--both direct and retrograde as referred to RTC. However, transport of probes toward MMSC was more efficient. One significant result of such transport was appearance of renal-specific Tamm-Horsfall protein in MMSC, indicating induction of their differentiation into kidney tubular cells. We conclude that transfer of cellular compartments between renal and stem cells could provide differentiation of MMSC when transplanted into kidney and result in therapeutic benefits in renal failure.
Article: Bi-directional exchange of membrane components occurs during co-culture of mesenchymal stem cells and nucleus pulposus cells.[show abstract] [hide abstract]
ABSTRACT: Mesenchymal stem cell (MSC)-based therapies have been proposed as novel treatments for intervertebral disc (IVD) degeneration. We have previously demonstrated that when MSCs are co-cultured with nucleus pulposus (NP) cells with direct cell-cell contact, they differentiate along the NP lineage and simultaneously stimulate the degenerate NP cell population to regain a normal (non-degenerate) phenotype, an effect which requires cell-cell communication. However, the mechanisms by which NP cells and MSCs interact in this system are currently unclear. Thus, in this study we investigated a range of potential mechanisms for exchange of cellular components or information that may direct these changes, including cell fusion, gap-junctional communication and exchange of membrane components by direct transfer or via microvesicle formation. Flow cytometry of fluorescently labeled MSCs and NP cells revealed evidence of some cell fusion and formation of gapjunctions, although at the three timepoints studied these phenomena were detectable only in a small proportion of cells. While these mechanisms may play a role in cell-cell communication, the data suggests they are not the predominant mechanism of interaction. However, flow cytometry of fluorescently dual-labeled cells showed that extensive bi-directional transfer of membrane components is operational during direct co-culture of MSCs and NP cells. Furthermore, there was also evidence for secretion and internalization of membrane-bound microvesicles by both cell types. Thus, this study highlights bi-directional intercellular transfer of membrane components as a possible mechanism of cellular communication between MSC and NP cells.PLoS ONE 01/2012; 7(3):e33739. · 4.09 Impact Factor
Article: Tunneling nanotubes provide a unique conduit for intercellular transfer of cellular contents in human malignant pleural mesothelioma.[show abstract] [hide abstract]
ABSTRACT: Tunneling nanotubes are long, non-adherent F-actin-based cytoplasmic extensions which connect proximal or distant cells and facilitate intercellular transfer. The identification of nanotubes has been limited to cell lines, and their role in cancer remains unclear. We detected tunneling nanotubes in mesothelioma cell lines and primary human mesothelioma cells. Using a low serum, hyperglycemic, acidic growth medium, we stimulated nanotube formation and bidirectional transfer of vesicles, proteins, and mitochondria between cells. Notably, nanotubes developed between malignant cells or between normal mesothelial cells, but not between malignant and normal cells. Immunofluorescent staining revealed their actin-based assembly and structure. Metformin and an mTor inhibitor, Everolimus, effectively suppressed nanotube formation. Confocal microscopy with 3-dimensional reconstructions of sectioned surgical specimens demonstrated for the first time the presence of nanotubes in human mesothelioma and lung adenocarcinoma tumor specimens. We provide the first evidence of tunneling nanotubes in human primary tumors and cancer cells and propose that these structures play an important role in cancer cell pathogenesis and invasion.PLoS ONE 01/2012; 7(3):e33093. · 4.09 Impact Factor