Our study showed that neurite length

Our study showed that neurite length and the ratio of apoptotic wst-1 in FALS- and FUSH517D/H517D iPSC-derived neurons were the same as in control motor neurons. With several stresses especially in glutamate treatment, however, FALS- and FUSH517D/H517D HB9-positive motor neurons exhibited shorter neurites and an increased cleaved-CASPASE3-positive cell ratio compared with control HB9-positive motor neurons. These results suggest that FALS iPSC-derived motor neurons are vulnerable to oxidative and excitatory stresses and there is a possibility that these phenomena are relevant to ALS-like phenotypes. We thus determined that these ALS patient-specific iPSC-derived motor neurons recapitulate disease phenotypes. Recently, other groups also established in vitro FUS iPSCs models showing the inclusion of the stress granule of FUS mutant proteins (Lenzi et al., 2015; Liu et al., 2015). In addition to these findings, we observed additional ALS-like phenotypes and motor neuron vulnerability under some stress conditions and discovered potential biologically relevant aberrant gene expressions. Importantly, these events are also confirmed by the use of genome editing technology to generate isogenic mutant FUS H517D, suggesting that the present in vitro FALS model is able to recapitulate the ALS-like phenotypes. Based on these results, our mutant FUS-associated iPSC-derived HB9-positive motor neurons can be added to the list of model systems that may provide general tools for use in the analysis of the pathogenic process and drug screening studies in human motor neuron disorders.
Experimental Procedures
Author Contributions
Acknowledgments We thank the members of the Okano laboratory for helpful comments and discussion. The research described in this study was supported by grants from the Program for Intractable Disease Research Utilizing Disease-specific iPS Cells funded by the Japan Science and Technology Agency (JST)/Japan Agency for Medical Research and Development (A-MED) to H.O., Ministry of Health, Labor and Welfare (MHLW) of Japan to H.O., Translational Research Network Program from A-MED to Keio University, the New Energy and Industrial Technology Development Organization (NEDO), and the Ministry of Education, Science, Sports and Culture (MEXT) (Scientific Research on Innovative Area, a MEXT Grant-in-Aid Project FY2014-2018 “Brain Protein Aging and Dementia Control”). H.O. is a scientific consultant for San Bio Co., Ltd.
Introduction Cell transplantation therapies have great promise for treatment against neurodegenerative disorders such as Parkinson\'s disease (PD). Accordingly, several groups have reported methods to induce midbrain dopaminergic (DA) neurons from human pluripotent stem cells, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) (Kriks et al., 2011; Kirkeby et al., 2012; Denham et al., 2012; Sundberg et al., 2013), and a robust and efficient induction method of midbrain DA progenitors was established toward clinical application (Doi et al., 2014). These ESC/iPSC-derived DA neurons can improve the rotational behavior of 6-hydroxydopamine (6-OHDA)-lesioned hemi-parkinsonian rat models (Kriks et al., 2011; Kirkeby et al., 2012; Sundberg et al., 2013; Doi et al., 2014). Histological and electrophysiological analyses have revealed that grafted DA neurons can functionally integrate into host neural circuits (Mahalik et al., 1985; Sortwell et al., 1998; Sørensen et al., 2005; Tønnesen and Kokaia, 2012). Importantly, the survival and maturation of grafted neural progenitor cells depend on conditional cues from the host brain environment (Nishino et al., 2000; Morizane et al., 2013; Nishimura et al., 2015). Moreover, it has been reported that the adult brain has endogenous potential to recruit neural stem/progenitor cells for neuronal function repair (Höglinger et al., 2004; Paez-Gonzalez et al., 2014). Evoking this potential may promote graft-to-host synaptic connection for effective cell transplantation therapy for PD. However, which neurons in the striatum optimally form functional synapses with the grafted DA neurons to achieve long-term recovery remains unknown.