Role of Nox4 in Neuronal Differentiation of Mouse Subventricular Zone Neural Stem Cells

Abstract

Reactive oxygen species (ROS), at appropriate concentrations, mediate various normal cellular functions, including defense against pathogens, signal transduction, cellular growth, and gene expression. A recent study demonstrated that ROS and ROS-generating NADPH oxidase (Nox) are important in self-renewal and neuronal differentiation of subventricular zone (SVZ) neural stem cells in adult mouse brains. In this study, we found that endogenous ROS were detected in SVZ neural stem cells cultured from postnatal mouse brains. Nox4 was predominantly expressed in cultured cells, while the levels of the Nox1 and Nox2 transcripts were very low. In addition, the Nox4 gene was highly upregulated (by up to 10-fold) during neuronal differentiation. Immunocytochemical analysis detected the Nox4 protein mainly in neurons positive for the neuronal specific tubulin Tuj1. After differentiation, endogenous ROS were detected exclusively in neuron-like cells with processes. In addition, perturbation of the cellular redox state with N-acetyl cysteine, a ROS scavenger, during neuronal differentiation greatly inhibited neurogenesis. Lastly, knockdown of Nox4 using short hairpin RNA decreased neurogenesis. These findings suggest that Nox4 may be a major ROS-generating enzyme in postnatal SVZ neural stem cells, and Nox4-mediated ROS generation may be important in their neuronal differentiation.

Naringin Supplementation during Pregnancy Induces Sex and Region-Specific Alterations in the Offspring’s Brain Redox Status

“…It is well established that the redox signaling is essential during neurodevelopment since the transition from neural stem cells (NSC) to a neuron involves a metabolic shift from a glycolytic to a more oxidative based metabolism, which consequently increases the amount of mitochondrial-derived reactive oxygen species (ROS) [ 64 , 65 ]. Moreover, other sources of ROS, such as the NADPH-oxidase enzyme family, have also been proposed to play particularly important roles in inducing the neurogenic process [ 66 , 67 , 68 ]. Consequently, such an increase in the ROS induces the activation of several signaling cascades involved in the commitment of the NSC and its differentiation into a fully grown neuron [ 68 , 69 , 70 , 71 ].…”

“…Although the transient increase in ROS is essential to induce the commitment of the NSC, such a process needs to be tightly regulated to maintain a physiological and tolerable intracellular level of reactive species [ 72 ]. On one hand, persistent and particularly high amounts of ROS, which exceed a physiologically acceptable range, can induce oxidative stress, hinder axonal growth, and impair neurodevelopment, while on the other hand, low ROS amounts have been linked to the maintenance of the quiescent state of the NSC, which reduces its differentiation into neurons [ 67 , 73 , 74 ].…”

Long-Term Antioxidant Metal–Organic Frameworks

“…A VersaMax microplate reader was used for quantitative analysis of the cell viability. WST-8 Cell Viability Assay Kit was purchased from Quanti-Max, and N5 medium was prepared in advance according to a previous report . Phosphate-buffered saline (PBS) was purchased from GenDEPOT.…”

NADPH Oxidases: Redox Regulators of Stem Cell Fate and Function

“…NOXs, together with the mitochondria electron-transport chain, are the main intracellular sources of ROS [ 15 ]. However, ROS generated in mitochondria are a byproducts of cellular respiration meanwhile NOXs deliberately produce ROS, and this production is tightly regulated by the cell [ 16 ]. Three major forms of intracellular ROS exist: superoxide anions (O − ), hydrogen peroxide (H 2 O 2 ), and hydroxyl radicals (OH − ) [ 17 ].…”

“…The up-regulation of NOX4 represents a mechanism to modulate different cellular processes since H 2 O 2 produced by NOX4 regulates intracellular signaling [ 146 , 147 ]. Park et al [ 16 ] observed that NOX4 was predominantly expressed among NOX isoforms in SVZ NSCs cultured from mouse neonates and its expression increased during neuronal differentiation. In addition, the treatment of SVZ NSC cultures with the antioxidant N-acetyl cysteine (NAC) reduced neurogenesis as well as the knockdown of NOX4.…”