Vol.:(0123456789)
1 3
Cellular and Molecular Neurobiology (2018) 38:1051–1065
https://doi.org/10.1007/s10571-018-0576-7
ORIGINAL RESEARCH
Involvement of Nuclear Receptor REV‑ERBβ in Formation of Neurites
and Proliferation of Cultured Adult Neural Stem Cells
Koji Shimozaki
1
Received: 29 September 2017 / Accepted: 27 January 2018 / Published online: 3 February 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2018
Abstract
Neural stem cells (NSCs) serve as the source of both neurons and support cells, and neurogenesis is reportedly linked to the
circadian clock. This study aimed to clarify the functional role of the circadian rhythm-related nuclear receptor, REV-ERBβ,
in neurogenesis of NSCs from adult brain. Accordingly, Rev-erbβ expression and the effect of Rev-erbβ gene-specific knock-
down on neurogenesis in vitro was examined in adult rodent NSCs. Initial experiments confirmed REV-ERBβ expression in
cultured adult NSCs, while subsequent gene expression and gene ontogeny analyses identified functional genes upregulated
or downregulated by REV-ERBβ. In particular, expression levels of factors associated with proliferation, stemness, and
neural differentiation were affected. Knockdown of Rev-erbβ showed involvement of REV-ERBβ in regulation of cellular
proliferation and self-renewal of cultured adult NSCs. Moreover, Rev-erbβ-knockdown cells formed neurons with a slightly
shrunken morphology, fewer new primary neurites, and reduced length and branch formation of neurites. Altogether, this
suggests that REV-ERBβ is involved in neurite formation during neuronal differentiation of cultured adult NSCs. In summary,
REV-ERBβ is a known circadian regulatory protein that appears to be involved in neurogenesis via regulation of networks
for cell proliferation and neural differentiation/maturation in adult NSCs.
Keywords REV-ERBβ · Neural stem cells · Adult neurogenesis · Proliferation · Neurite outgrowth
Introduction
Neural stem cells (NSCs) serve as the source of both neurons
and support cells, such as astrocytes and oligodendrocytes.
Most NSCs undergo repeated self-renewal during neural
development. They maintain their unique cellular proper-
ties during this process, but eventually assume a final differ-
entiated form appropriate to their developmental stage and
niche. However, in limited regions of the adult brain, some
NSCs are maintained in a stem cell-like state after the organ-
ism ceases development. This quality, called “stemness,”
is a combination of self-renewal ability, pluripotency, and/
or multipotency, which allows this cell subpopulation to
continually generate new neurons during the lifetime of
the organism (Altman and Das 1965; Eriksson et al. 1998;
Gage 2000; Alvarez-Buylla and Lim 2004). In the brain of
adult mammals, newborn neurons are produced in specific
neuronal niches [e.g., the subventricular zone (SVZ) and
subgranular zone (SGZ)], which contain NSCs and neural
progenitor cells (NPCs) in quiescent and active phases of the
cell cycle. In the SVZ and SGZ, progeny of these cells dif-
ferentiate into olfactory bulb interneurons and hippocampal
granular neurons, respectively (Doetsch et al. 1999; Kem-
permann et al. 2004). Adult NSCs resemble astrocyte-like
cells and exhibit biochemical properties that include simul-
taneous expression of the nuclear protein, Sox2, and inter-
mediate filament proteins such as nestin and glial fibrillary
acidic protein (GFAP). Neurogenesis (particularly in the
SGZ) plays important roles in several adult brain processes,
such as memory formation and extinction, pattern separa-
tion in memory, learning and cognition, and potentiation of
antidepressant efficacy (Shors et al. 2001; Zhao et al. 2008;
Aimone et al. 2011; Akers et al. 2014; Johnston et al. 2016).
Adult neurogenesis occurs via several cell biological pro-
cesses: (1) proliferation, migration, and differentiation of
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s1057 1-018-0576-7) contains
supplementary material, which is available to authorized users.
* Koji Shimozaki
shimozak@nagasaki-u.ac.jp
1
Division of Functional Genomics, Life Science Support
Center, Nagasaki University, 1-12-4 Sakamoto,
Nagasaki 852-8523, Japan
@Phil_Robichaud
@deepthiw
@JoseServera