Generation of cell-derived three dimensional extracellular matrix substrates from two dimensional endothelial cell cultures.

Within the cellular microenvironment, extracellular matrix (ECM) proteins are critical nonsoluble signaling factors that modulate cell attachment, migration, proliferation, and differentiation. We have developed a simple method to isolate and process ECM from endothelial cell cultures to create a three-dimensional (3D) ECM substrate. Endothelial cell monolayers were chemically lysed and enzymatically digested to isolate a thin, two-dimensional (2D) ECM substrate. This thin 1.8 µm 2D ECM was collected and applied to a solid support to produce 12-16-fold thicker 3D ECM substrates with average thicknesses ranging from 21 to 29 µm. The biological activity of isolated ECM was assessed by cell culture. Neural progenitor cells were cultured on endothelial-produced ECM, and unlike the thin 2D ECM, which was quickly remodeled by cells, 3D ECM substrates remained in culture for an extended period (>7 days), suggesting that a continuous signaling cue for in vitro experiments may be provided. This simple method for creating 3D ECM substrates can be applied to a variety of cell culture models for studies aimed at identifying the signaling effects of the ECM within cellular microenvironments.

Cryopreservation of transfected primary dorsal root ganglia neurons.

Primary dorsal root ganglia (DRG) neurons are often used to investigate the relative strength of various guidance cues to promote re-growth in vitro. Current methods of neuron isolation are laborious and disposal of excess dissected cells is inefficient. Traditional immunostaining techniques are inadequate to visualize real-time neurite outgrowth in co-culture. Cryopreservation, in combination with transfection techniques, may provide a viable solution to both under-utilized tissue and insufficient methods of visualization. This study aims to qualitatively and quantitatively demonstrate successful cryopreservation of primary transfected and non-transfected DRG neurons. Fluorescent micrographs were used to assess morphology after 24h in culture and suggest similarities between freshly isolated neurons and neurons which have been transfected and/or cryopreserved. Quantitative measurements of neuron outgrowth (specifically, primary neurites, branch points and total neurite length) indicate that neuron outgrowth is not altered by cryopreservation. Transfected neurons have stunted outgrowth at 24h.