methylcellulose and arginyl-glycyl-aspartic-acid

Transplantation of pluripotent stem cells and their differentiated progeny has the potential to preserve or regenerate functional pathways and improve function after central nervous system injury. However, their utility has been hampered by poor survival and the potential to form tumors. Peptide-modified biomaterials influence cell adhesion, survival and differentiation in vitro, but their effectiveness in vivo remains uncertain. We synthesized a peptide-modified, minimally invasive, injectable hydrogel comprised of hyaluronan and methylcellulose to enhance the survival and differentiation of human induced pluripotent stem cell-derived oligodendrocyte progenitor cells. Cells were transplanted subacutely after a moderate clip compression rat spinal cord injury. The hydrogel, modified with the RGD peptide and platelet-derived growth factor (PDGF-A), promoted early survival and integration of grafted cells. However, prolific teratoma formation was evident when cells were transplanted in media at longer survival times, indicating that either this cell line or the way in which it was cultured is unsuitable for human use. Interestingly, teratoma formation was attenuated when cells were transplanted in the hydrogel, where most cells differentiated to a glial phenotype. Thus, this hydrogel promoted cell survival and integration, and attenuated teratoma formation by promoting cell differentiation.

Topics: Animals; Behavior, Animal; Cattle; Cell Differentiation; Cell Lineage; Cell Movement; Cell Survival; Disease Models, Animal; Female; Flow Cytometry; Humans; Hyaluronic Acid; Hydrogel, Polyethylene Glycol Dimethacrylate; Induced Pluripotent Stem Cells; Injections; Methylcellulose; Oligodendroglia; Oligopeptides; Platelet-Derived Growth Factor; Rats, Sprague-Dawley; Spinal Cord Injuries; Teratoma

Adinbitor was cloned from Agkistrodon halys brevicaudus stejneger and characterized as a novel disintegrin. In this study, total RNA was extracted from venom gland and used in RT-PCR to generate a cDNA which is 219 bp long. The sequence encoded a polypeptide composed of 73 amino acids, including 12 cysteines, an RGD motif, and the signature motif of disintergrin. Recombinant Adinbitor (rAdinbitor) was expressed in E. coli and purified by using the His. Bind affinity chromatography. The IC(50) for inhibiting human platelet aggregation and bFGF-induced proliferation of ECV304 cells was 6 microM and 0.89 microM respectively. Furthermore, Adinbitor significantly inhibited angiogenesis both in vivo and in vitro. Taken together, these results suggested that Adinbitor had typical functions of disintegrins.

Topics: Agkistrodon; Amino Acid Motifs; Amino Acid Sequence; Animals; Base Sequence; Cell Proliferation; Cell Survival; Chick Embryo; Chromatography; Cloning, Molecular; Collagen; Crotalid Venoms; Disintegrins; DNA, Complementary; Dose-Response Relationship, Drug; Drug Combinations; Electrophoresis, Polyacrylamide Gel; Fibroblast Growth Factor 2; Genetic Vectors; Inhibitory Concentration 50; Laminin; Methylcellulose; Molecular Sequence Data; Neovascularization, Pathologic; Oligopeptides; Platelet Aggregation; Proteoglycans; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA

Identification of receptor activator of nuclear factor-kappaB (RANK) and RANK-ligand (RANKL) has provided new insights into the osteoclast differentiation pathway. Osteoclast precursor cells were isolated using monoclonal antibodies against c-Fms and RANK, and the effect of adherence on the in vitro differentiation and proliferation of these cells was examined in 2 different types of stromal-cell-free culture systems: a semisolid culture medium (a nonadherent system) and a liquid culture medium (an adherent system). Osteoclast precursor cells were not able to differentiate into mature osteoclasts efficiently in the semisolid culture system. Trimerized RANKL enhanced osteoclast differentiation in semisolid cultures, but not to the extent seen when cells were allowed to adhere to plastic. Initial precursor cells were capable of differentiating into macrophages or osteoclasts. Once these cells were transferred to adherent conditions, striking differentiation was induced. Multinuclear cells were observed even after they had displayed phagocytic activity, which suggests that cell adhesion plays an important role in the differentiation of osteoclast precursor cells. Integrins, especially the arginine-glycine-aspartic acid (RGD)-recognizing integrins alpha(v) and beta(3), were needed for osteoclast-committed precursor cells to proliferate in order to form multinuclear osteoclasts, and the increase in cell density affected the formation of multinuclear cells. A model of osteoclast differentiation with 2 stages of precursor development is proposed: (1) a first stage, in which precursor cells are bipotential and capable of anchorage-independent growth, and (2) a second stage, in which the further proliferation and differentiation of osteoclast-committed precursor cells is anchorage-dependent. (Blood. 2000;96:4335-4343)

Topics: Animals; Antibodies, Monoclonal; Antigens, CD; Carrier Proteins; Cell Adhesion; Cell Culture Techniques; Cell Differentiation; Cell Division; Cells, Cultured; Culture Media; Female; Giant Cells; Glycoproteins; Hematopoietic Stem Cells; Integrin alphaV; Integrin beta3; Leucine Zippers; Macrophage Colony-Stimulating Factor; Macrophages; Membrane Glycoproteins; Methylcellulose; Mice; Mice, Inbred C57BL; Models, Biological; Oligopeptides; Osteoclasts; Osteoprotegerin; Plastics; Platelet Membrane Glycoproteins; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptor, Macrophage Colony-Stimulating Factor; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor