Integrin-αvβ3 regulates thrombopoietin-mediated maintenance of hematopoietic stem cells.

Throughout life, one's blood supply depends on sustained division of hematopoietic stem cells (HSCs) for self-renewal and differentiation. Within the bone marrow microenvironment, an adhesion-dependent or -independent niche system regulates HSC function. Here we show that a novel adhesion-dependent mechanism via integrin-β3 signaling contributes to HSC maintenance.

Structural characterization of bioengineered human corneal endothelial cell sheets fabricated on temperature-responsive culture dishes.

For the purpose of corneal regenerative medicine, we fabricated human corneal endothelial cell sheets on temperature-responsive dishes, which could be non-invasively harvested as intact, transplantable sheets by simply reducing the culture temperature. Cells demonstrated hexagonal cell shape with numerous microvilli and cilia, and also exhibited abundant cytoplasmic organelles similar to these cells in vivo. Immunofluorescence for type IV collagen and fibronectin revealed that abundant extracellular matrix (ECM) was deposited on the basal surface throughout culture, and the deposited ECM was harvested along with the cell sheets by reducing culture temperature to 20 degrees C.

Thermally responsive polymer-grafted surfaces facilitate patterned cell seeding and co-culture.

Tissue engineering constructs that effectively duplicate natural tissue function must also maintain tissue architectural and organization features, particularly the integration of multiple cell types preserving distinct, integrated phenotypes. Cell-cell communication and biochemical cross-talk have been shown to be essential for the maintenance of differentiated cell functions in tissues and organs. Current limitations of cell-culture hinder progress in understanding the features and dynamics of heterotypic cell communication pathways critical to developing more sophisticated or effective tissue-engineered devices.