Neural stem cell neural differentiation in 3D extracellular matrix and endoplasmic reticulum stress microenvironment

Abstract

Successful neural stem cell (NSC) transplantation for treating neurological disorders is dependent on the effective differentiation of NSCs towards neurons especially in a pathological microenvironment. The purpose of this study was to evaluate NSC differentiation in an in vivo-like three-dimensional (3D) pathological microenvironment. We investigated use of a nano-scale electrospinning scaffold called nanomatrix incorporated into extracellular matrix proteins (ECM) for improvement of NSC differentiation capacity even under the endoplasmic reticulum (ER) stress condition, which generally occurred in various neurological disorders. ECM proteins used here included collagen, collagen + laminin, Matrigel, and Matrigel + laminin groups. NSCs cultured in Matrigel + laminin group were more potent for neural differentiation in comparison with other ECM groups. Addition of nanomatrix to the Matrigel + laminin group resulted in the enhancement of neuron marker TUJ1 expression and an increase in the length of neurite outgrowth even though the culture was treated with a toxic dose of tunicamycin, a commonly used ER stress inducer. Similarly, the downregulated expression levels of hippocampal granule neuron markers of PROX1 and FOXG1 in response to tunicamycin were reversed by addition of nanomatrix to the Matrigel + laminin group. The protective mechanism of nanomatrix combined with Matrigel and laminin was found to regulate unfolded protein response (UPR) signaling molecules, including Bip, ATF4 and CHOP. Taken together, these results implicated that combination of nanomatrix with Matrigel and laminin contributed to neural differentiation from NSCs even under an ER stress condition. It should be useful for researching the control of transplanted or endogenous NSC differentiation, especially in ER stress-related neurological diseases.