Tightly Anchored Tissue-Mimetic Matrices as Instructive Stem Cell Microenvironments Investigators describe a methodology that permits reliable anchorage of native cell-secreted extracellular matrix (ECM) to culture carriers. They validated their approach by fabricating two types of human bone marrow-specific ECM substrates that were robust enough to support human mesenchymal stem cells (MSCs) and hematopoietic stem and progenitor cells in vitro. [Nat Methods] Abstract Physical Limits of Cell Migration: Control by ECM Space and Nuclear Deformation and Tuning by Proteolysis and Traction Force Using matrix metalloproteinase (MMP)-degradable collagen lattices or nondegradable substrates of varying porosity, researchers quantitatively identified the limits of cell migration by physical arrest. MMP-independent migration declined as linear function of pore size and with deformation of the nucleus, with arrest reached at 10% of the nuclear cross section. [J Cell Biol] Abstract The Extracellular Matrix Glycoprotein Tenascin-R Affects Adult but Not Developmental Neurogenesis in the Olfactory Bulb Scientists showed that the extracellular matrix glycoprotein tenascin-R (TNR) is produced in the granule cell layer of the olfactory bulb (OB) and that its expression increases during postnatal development. Time-lapse video imaging and morphological analyses revealed that a lack of TNR decreases the radial migration of neuronal precursors in the adult, but not in the developing OB. [J Neurosci] Abstract Integrin α3β1-CD151 Complex Regulates Dimerization of ErbB2 via RhoA Integrin α3β1 regulates adhesive interactions of cells with laminins and have a critical role in adhesion-dependent cellular responses. Here, the authors examined the role of α3β1-integrin in ErbB2-dependent proliferation of breast cancer cells in three-dimensional laminin-rich extracellular matrix. [Oncogene] Abstract Laminin β1a Controls Distinct Steps during the Establishment of Digestive Organ Laterality Scientists identified a mutation affecting zebrafish laminin β1a (lamb1a) that disrupts left-right asymmetry of the liver and pancreas. In these mutants, the liver spans the midline and the ventral pancreatic bud remains split into bilateral structures. They showed that lamb1a regulates asymmetric left-right gene expression in the lateral plate mesoderm. Their results provide cellular and molecular mechanisms by which extracellular matrix proteins regulate left-right organ morphogenesis. [Development] Abstract Microfluidics Embedded within Extracellular Matrix to Define Vascular Architectures and Pattern Diffusive Gradients To generate temporally and spatially defined soluble gradients within a 3D cell culture environment, investigators developed an approach to patterning microfluidically ported microchannels that pass through a 3D extracellular matrix (ECM). Micromolded networks of sacrificial conduits ensconced within an ECM gel precursor solution are dissolved following ECM gelation to yield functional microfluidic channels. [Lab Chip] Abstract Fibronectin and Integrin Alpha 5 Play Requisite Roles in Cardiac Morphogenesis Fibronectin and its major receptor, integrin α5β1 are required for embryogenesis. These mutants have similar phenotypes, although, defects in integrin α5-deficient mice are milder. Scientists examined heart development in those mutants, in which the heart is formed, and discovered that both fibronectin and integrin α5 were required for cardiac morphogenesis, and in particular, for the formation of the cardiac outflow tract. [Dev Biol] Abstract |