27The cerebellum has been considered as a major component of the motor system.
It sends outputs to a variety of brain regions that are related to motor functions and
receives feedback inputs from them. It is well known that the damage in the cerebel-
lum leads to impairments in motor and postural control. In addition to the well-
known motor functions, recent studies, especially those in humans, have revealed an
involvement of the cerebellum in cognitive functions, such as attention, language
processing, and supervised learning. Several labs had attempted cerebellar induc-
tion from PSCs, but the efficiency of differentiation was low (Erceg et al. 2010 ;
Salero and Hatten 2007 ; Su et al. 2006 ; Tao et al. 2010 ). In addition, these protocols
have not yet been widely used by other researchers, and their reproducibility remains
to be confirmed. Such current circumstances hamper the research of cerebellar dis-
eases with the iPSC technologies, which have already been extensively used for
investigation of other neurological disorders (Wiethoff et al. 2015 ).
We recently demonstrated that cerebellar neurons are generated from PSCs
(Morino et al. 2015 ; Muguruma et al. 2010 , 2015 ). To effectively generate cerebellar
tissues from PSCs, we took an indirect strategy to induce the isthmic organizer tissue
that secondarily self-induces the cerebellar tissues. In this culture using hPSCs,
we found that hPSC self-organizes a polarized cerebellar structure in 3D culture.
Fig. 2.1 Self-induction of neural progenitors from hESCs in SFEBq culture. (Upper panel)
hESCs form an aggregate within few hours. The expressions of Oct3/4 and E-cadherin on day 1
gradually disappear by day 7. (Lower panel) Around 14 days, the majority of hESC-derived tissue
expresses Nestin and Pax6, which are markers for neural progenitors. Ecad E-cadherin. The scale
bars represent 100 μm (upper panel) and 200 μm (lower panel) (Modified from Muguruma 2016 )
2 Self-Organized Cerebellar Tissue fromfiHuman Pluripotent Stem Cells andfiIts...