Regulatory volume decrease in neural precursor cells: taurine efflux and gene microarray analysis.

BACKGROUND/AIMS Neural stem/ progenitor cells (NPCs) endure important changes in cell volume during growth, proliferation and migration. As a first approach to know about NPC response to cell volume changes, the Regulatory Volume Decrease (RVD) subsequent to hypotonic swelling was investigated. METHODS NPCs obtained from the mesencephalon and the subventricular zone of embryonic and adult mice, respectively, were grown and cultured as neurospheres. Cell volume changes were measured by large-angle light-scattering and taurine efflux by [(3)H]-taurine. Expression of genes encoding molecules related to RVD was analysed using a DNA microarray obtained from NPC samples. RESULTS Embryonic and adult NPCs exposed to osmolarity reduction (H15, H30, H40) exhibited rapid swelling followed by RVD. The magnitude, efficiency and pharmacological profile, of RVD and of [(3)H]-taurine osmosensitive efflux were comparable to those found in cultured brain cells, astrocytes and neurons. The relative expression of genes encoding molecules related to volume regulation, i.e. K(+) and Cl(-) channels, cotransporters, exchangers and aquaporins were identified in NPCs. CONCLUSION NPCs show the ability to respond to hypotonic-evoked volume changes by adaptative recovery processes, similar to those found in other cultured brain cells. Genes related to molecules involved in RVD were found expressed in NPCs.