MEMBRANE ELASTIC PROPERTIES DURING NEURAL PERCURSOR CELL DIFFERENTIATION

Neural precursor cells differentiate into several cell types as neurons, astrocytes and oligodendrocytes of the mammalian central nervous system that display distinct functions and morphological features. However, little is known about how cell surface mechanics vary during the differentiation process. In this work, by precisely measuring membrane tension and bending modulus using correlative optical tweezers and scanning electron microscopy (SEM), we map their variations and correlate them with changes in neural precursor cell morphology along their distinct differentiation fate, analyzed by immunofluorescence imaging in a confocal microscopy. Cells maintained in culture as neural precursors as well as those plated in neurobasal medium reveal a decrease in membrane tension over the first hours of culture followed by stabilization, with no change in bending modulus. During astrocyte differentiation, membrane tension initially decreases and then increases after 72 h, accompanied by consolidation of glial fibrillary acidic protein expression and striking actin reorganization, while bending modulus increases following observed alterations. For oligodendrocytes, the changes in membrane tension are less abrupt over the first hours, but their values subsequently decrease, correlating with a shift from oligodendrocyte marker O4 to myelin basic protein expressions and a remarkable actin reorganization, while bending modulus remains constant. Oligodendrocytes at later differentiation stages show membrane vesicles with similar membrane tension but higher bending modulus as compared to the cell surface. Altogether, our results display an entire spectrum of how membrane elastic properties are varying, thus contributing to a better understanding of neural differentiation from a mechanobiological perspective.