Methods for using cyclin-dependent kinase (CDK) inhibitors to enhance growth and self-renewal of progenitor cells, in vitro and in vivo.

Hematopoietic stem cells are extremely difficult to maintain or expand in vitro. Two observations in traditional long-term bone marrow cultures strongly suggest that macrophages may be at the root of the problem: First, micromolar concentrations of hydrocortisone improve the longevity of long-term bone marrow cultures and hydrocortisone is known as a potent inhibitor of macrophage production of pro-inflammatory cytokines, chemokines, enzymes, nitrogen oxide and reactive oxygen species and redirects macrophages to the anti-inflammatory differentiation pathway; Second, the decline of hematopoiesis in long-term bone marrow cultures coincides with the development of large numbers of adherent and non-adherent macrophages including foreign body giant cells. These adherent macrophages and foreign body giant cells exhibit well-spread morphology, contain numerous lysosomes and phagolysosomes in the cytoplasm and are metabolically active. We hypothesize that hydrocortisone fails to suppress all aspects of macrophage pro-inflammatory activation/differentiation, resulting in the production of inhibitors or toxins of hematopoiesis. Macrophage adhesion in cell culture depends on serum proteins pre-adsorbed to the tissue-culture-treated polystyrene (TC-PS), which adsorbs proteins via mostly hydrophilic interactions. TC-PS is used in almost all tissue culture devices currently available. Cellular adhesion provides a strong stimulus for metabolic, mitotic and certain gene activities. Therefore, we seek to reduce macrophage adhesion and activation by culturing bone marrow cells in tissue culture devices composed of or covered with polymers with very different protein-binding characteristics than TC-PS such as polyethylene (PE) and other polyolefins, the latter bind proteins via exclusively hydrophobic interactions. As a result, polyolefins bind different proteins and in lower quantities than TC-PS. Furthermore, PE does not contain additional chemical features like the phenolic rings of polystyrene that might contribute to protein binding and macrophage adhesion/activation. Using these new culture devices, we developed a drastically different long-term bone marrow culture, the “Low Macrophage-Adhesion/Activation” (LoMAC) bone marrow culture. In LoMAC bone marrow culture, hematopoiesis continues for months to over a year and hematopoietic stem cells are amplified gradually. In stark contrast to traditional long-term bone marrow cultures, de novo erythropoiesis and megakaryocytopoiesis proceed robustly in the LoMAC bone marrow culture and B-lymphocyte and natural killer cell progenitors can be continuously derived. Thus, these new culture devices and the associated LoMAC c

The present description provides improved methods for generating thymic epithelial progenitor (TEP) cells from pluripotent stem (PS) cells in vitro. Also provided are isolated invitro cell populations, compositions, and systems comprising TEP cells produced in vitro. Compositions and systems of cell populations of thymic epithelial cells and subpopulations thereof, as well as cells formed during different stages of differentiation of PS cells into thymic epithelial cells and subpopulations thereof are provided.

The present invention relates to a method for inducing differentiation, into chondrocytes, of cord blood mononuclear cell-derived induced pluripotent stem cells. In a case where a chondrogenic pellet produced by the method of the present invention is transplanted into a cartilage damage area in vivo, regeneration of cartilage can be effectively exhibited by differentiated chondrocytes. In such a case, an effective cartilage regeneration capacity can be exhibited as compared with a case where chondrocytes produced by differentiation induction with the addition of a recombinant growth factor are transplanted. Thus, the present invention can be usefully used for tissue engineering therapies.

The present invention relates to stem cells derived from villi adjacent to the chorionic plate (VCP), and a cell therapeutic agent comprising same. Stem cells derived from the tissue of VCP comprising, of the total villi, the region that is ⅓ of the distance from the area adjacent to the chorionic plate up to the villus distal part, and the basal region of the villi, according to the present invention, exhibit uniform growth characteristics, and proliferation characteristics superior to those of stem cells derived from other placental tissue, and exhibit remarkably excellent differentiation into cartilage, bone and fat, thereby being effectively usable in various tissue regeneration treatments requiring the regeneration of cartilage, bone and fat, and, particularly, in cartilage regeneration and osteoarthritis treatment.

The invention generally features compositions comprising induced pluripotent stem cell progenitors (also termed reprogramming progenitor cells) and methods of isolating such cells. The invention also provides compositions comprising induced pluripotent stem cells (iPSCs) derived from such progenitor cells. Induced pluripotent stem cell progenitors generate iPSCs at high efficiency.

Methods for derivation, culture, and maturation of small hepatic progenitor cells are described.

The present invention relates to methods for developing engineered T-cells for immunotherapy that are non-alloreactive. The present invention relates to methods for modifying T-cells by inactivating both genes encoding T-cell receptor and an immune checkpoint gene to unleash the potential of the immune response. This method involves the use of specific rare cutting endonucleases, in particular TALE-nucleases (TAL effector endonuclease) and polynucleotides encoding such polypeptides, to precisely target a selection of key genes in T-cells, which are available from donors or from culture of primary cells. The invention opens the way to standard and affordable adoptive immunotherapy strategies for treating cancer and viral infections.

A method of expanding TCRalpha deficient T-cells by expressing pTalpha or functional variants thereof into said cells, thereby restoring a functional CD3 complex. This method is particularly useful to enhance the efficiency of immunotherapy using primary T-cells from donors. This method involves the use of pTalpha or functional variants thereof and polynucleotides encoding such polypeptides to expand TCRalpha deficient T-cells. Such engineered cells can be obtained by using specific rare-cutting endonuclease, preferably TALE-nucleases. The use of Chimeric Antigen Receptor (CAR), especially multi-chain CAR, in such engineered cells to target malignant or infected cells. The invention opens the way to standard and affordable adoptive immunotherapy strategies for treating cancer and viral infections.

The present invention relates to a method for in vitro expansion of mature erythroid cells. More specifically, the present invention relates to a method for obtaining concentrated erythrocytes by culturing erythroid cells at high density so as to allow the cells to physically and directly come in contact with each other. Particularly, the method of the present invention is very useful in that it is possible to obtain a large amount of clinically useful concentrated erythrocytes through a small container such as a test tube-sized bioreactor.