Fibroblasts fusions

Figure 2. Ultrastructural aspects of M813 virus-induced ceii fusion as shown by replica preparation technique, (a) Cell surface replica of a PA317 fibroblast after incubation for 30 min at 4°C with medium containing M813 virus. Numerous microvilli extend from the slightly folded cell surface. The...

Correa-Duarte et al. [24] MW CNT, oxidized Fibroblasts of mice (L929) -inoculation to CNT, observation - 7 days Formation of the isolated cells, fusion after 7 days, absence of cytotoxicity... 

Feeder cells for fusion cultures (see Note 6) essential for fusions employing rat myelomas. Quickly thaw irradiated rat fibroblasts, prepared as described in Note 6, just before commencing the cell fusion. Add the cells to 10 mL of serum-free DMEM, centrifuge, and wash once in serum-free DMEM Resuspend feeders in HAT medium just before addition of the fusion mixture. Alternatively, use thymocytes from spleen donors (mouse). 

Centrifuge for 3 min at 400g, and then resuspend the cells in 200 mL HAT selection medium, and add irradiated fibroblast or thymocyte feeder cells. Plate 2-mL aliquots into four 24-well plates or, if necessary, five 96-well plates (fusions with SP2/0 myeloma) (see Note 6). 

Faigle, W., Colucci-Guyon, E., Louvard, D., Amigorena, S., and Galli, T. (2000). Vimentin filaments in fibroblasts are a reservoir for SNAP23, a component of the membrane fusion machinery. Mol. Biol. Cell 11, 3485-3494. 

DOPE containing CL/DNA complexes in mammalian cell cultures exhibit the ii structure rather than the found in DOPC containing complexes. As revealed by optical microscopy, complexes remained stable inside cells and attached to giant anionic vesicles, whereas Hjj complexes showed fusion of their lipid with the mouse fibroblast cell membranes (Figure 10.12) or giant anionic vesicles that results in DNA release. 

Specifically, the data reviewed in Chapters 12 and 13 indicate that LCM are rapidly removed from the circulation by the tumor the maximum accumulation of LCM in the tumor area occurs within the first 30 min after administration (ref. 531). These rapid kinetics for LCM uptake are quite consistent with the well-documented kinetics long-known for the LDL receptor-mediated endocytic pathway (ref. 616). For example, Goldstein et al. (ref. 643) reported that LDL-ferritin bound to coated pits at 4°C is rapidly internalized when fibroblasts in tissue culture are warmed to 37°C. In this uptake process, the coated pits invaginate to form coated endocytic vesicles. After 5 to 10 min at 37°C, LDL-ferritin is observed in lysosomes as the result of their fusion with the incoming coated vesicles (ref. 643). The rapid sequence of events visualized in electron micrographs precisely parallels biochemically-derived data on the rapid uptake and degradation of radiolabeled LDL (ref. 644,645). 

Driesen RB, Dispersyn GD, Verheyen FK, et al. Partial cell fusion a newly recognized type of communication between dedifferentiating cardiomyocytes and fibroblasts. Cardiovasc Res 2005 68 37-46. 

Some cells, such as hybridomas, stem, and hematopoietic cells may require a class of proteins known as interleukins, especially IL-6. This compound can substitute for feeder cells (such as those of the peritoneal exudates or spleen, fibroblasts or timocytes) in the post-fusion stage of hybridoma cultures. IL-6 is secreted by monocytes, T lymphocytes, and endothelial cells and is effective in the stimulation of hybridomas of different species, including lineages that are difficult to cultivate, such as human-mouse and rat-mouse hybrids. IL-6 also presents a synergistic effect with other interleukins to increase antibody production. 

Feeder cells for fusion cultures ( eNote 5. Essential for fusions employing rat myelomas) Three hours to one day before fusion, 2—4 x 10 rat fibroblasts in 10 mL of DMEM and contained in a 30 mL plastic universal are irradiated with about 30 Gy (3000 rad) of X- or T rays. Dilute with 90 mL of HT (3 h before fusion) or DMEM containing 10% FCS (1 d before fusion) and plate 1-mL aliquots into four 24-well plates or 0.2-mL aliquots into five 96-welI plates. Alternatively, use thymocytes from spleen donors (mouse). 

A cDNA encoding human IL-17 (hIL-17) has been cloned from a CD4 T-cell library. The predicted 155-amino acid sequence contains an N-terminal signal peptide and exhibits 72% amino acid identity with HVS13 and 63% with murine CTLA-8, High levels of hIL-17 were induced from primary peripheral blood CD4 T cells on stimulation. When expressed in CVl/EBNA cells, recombinant hIL-17 was secreted in both glycosylated and nonglycosylated forms. An hIL-17 Fc fusion protein and supernatants from cells transfected with hIL-17 induced IL-6 and IL-8 production and enhanced the surface expression of the ICAM-1 in human fibroblasts. ... 

Fig. 11.4 Hypothetical model for integration of the major mechanisms of TAG storage and mobilization (1) conversion of fibroblasts/ preadipocytes into adipocytes, (2) biogenesis of forming LD at the ER membrane, (3) fusion of smaller LD to mature LD, (4) translocation of HSL from the cytosol to the surface of LD, (5) disassembly and reorganization at...

One criterion for a bona fide membrane-fusion protein is that membrane fusion can be reconstituted by transfection of the candidate fusion protein into nonfusing cells or by reconstitution into lipid vesicles (White, 1990 White, 1992 White and Blobel, 1989). Transfection of meltrin a into fibroblasts did not lead to an increase in cell fusion (Yagami-Hiromasa et al., 1995). Clearly, failure to reconstitute fusion does not rule out a role in fusion because the cellular fusion machinery may be more complex than viral fusion proteins. Muscle cells might contain other proteins that are required for meltrin a to promote membrane fusion but that are not expressed or active in fibroblasts. Ultimately, the identity of a bona fide cell-cell fusion protein or protein machine will only be determined by reconstituting membrane fusion with defined components. In the interim, it will be important to more accurately understand the roles of meltrin a and fertilin in the cascade of steps that result in membrane fusion and thereby perhaps distinguish between a direct and indirect role in fusion. 

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