Abstract
Conditioned medium has now gained increasing interest since the development of secretome-based therapy. Various types of cells have been studied as a source of the secretome. One of them is neural progenitor cells (NPCs). These are cells that capable of differentiating into neurons as well as glial cells. Indeed, the study on NPCs has risen in the last few decades, but the study on the differentiated cells has not clearly described. The most common procedures that widely used to get the conditioned medium is starvation. However, cell starvation may cause environmental stress and become an apoptotic trigger for the cells. In this study, we analyzed the effect of starvation on differentiated cells from E17 rat neural progenitor cells (NPCs) based on cells characteristics and secretome profile. We found that starvation decreased cells viability and affected the heterogeneity of the cell population. Astrocytes survived more under nutrient deprivation conditions, and the progenitor cells showed a higher tendency to differentiate to glial cells than neurons. Duration of starvation also influenced the secretome profile, alterations found in protein types and also their function in the biological process. During 24 hours of starvation, cells secreted proteins that were used to maintain cell growth, stimulate differentiation, and produce energy, but there were also proteins that identified and involved in autophagy activation. After 48 hours of starvation, astrocytes that became the dominant cells secreted proteins that try to keep protecting the remaining neurons.