Alpha 6 integrin is important for myogenic stem cell differentiation

A muscle progenitor cell population, other than muscle satellite cells, can be isolated and purified from porcine muscle tissue. We show the presence of at least two types of stem cells in porcine muscle: those that express α6 integrin and those that lack expression of this integrin type. By flow cytometry, we could select for myogenic stem cell populations expressing the neural cell adhesion molecule in the presence and absence of α6 integrin. The expression of α6 integrin showed an advantage in the formation of myotubes, possibly by an improved cell fusion capacity. This notion was strengthened by qRT-PCR analysis showing sustained PAX7, MYF5 and DESMIN expression and a strong myogenic differentiation capacity of this stem cell population. Selective inhibition of α6 integrin function, both by blocking antibodies and RNA interference, showed the importance of α6 integrin in myogenic differentiation of muscle stem cells. It is concluded that α6 integrin expression can be used as biomarker to select for highly myogenic cell populations in muscle tissue

A perfused human blood–brain barrier on-a-chip for high-throughput assessment of barrier function and antibody transport

Abstract Background Receptor-mediated transcytosis is one of the major routes for drug delivery of large molecules into the brain. The aim of this study was to develop a novel model of the human blood–brain barrier (BBB) in a high-throughput microfluidic device. This model can be used to assess passage of large biopharmaceuticals, such as therapeutic antibodies, across the BBB. Methods The model comprises human cell lines of brain endothelial cells, astrocytes, and pericytes in a two-lane or three-lane microfluidic platform that harbors 96 or 40 chips, respectively, in a 384-well plate format. In each chip, a perfused vessel of brain endothelial cells was grown against an extracellular matrix gel, which was patterned by means of surface tension techniques. Astrocytes and pericytes were added on the other side of the gel to complete the BBB on-a-chip model. Barrier function of the model was studied using fluorescent barrier integrity assays. To test antibody transcytosis, the lumen of the model’s endothelial vessel was perfused with an anti-transferrin receptor antibody or with a control antibody. The levels of antibody that penetrated to the basal compartment were quantified using a mesoscale discovery assay. Results The perfused BBB on-a-chip model shows presence of adherens and tight junctions and severely limits the passage of a 20 kDa FITC-dextran dye. Penetration of the antibody targeting the human transferrin receptor (MEM-189) was markedly higher than penetration of the control antibody (apparent permeability of 2.9 × 10−5 versus 1.6 × 10−5 cm/min, respectively). Conclusions We demonstrate successful integration of a human BBB microfluidic model in a high-throughput plate-based format that can be used for drug screening purposes. This in vitro model shows sufficient barrier function to study the passage of large molecules and is sensitive to differences in antibody penetration, which could support discovery and engineering of BBB-shuttle technologies