Mutant α-synuclein causes death of human cortical neurons via ERK1/2 and JNK activation.

Synucleinopathies refer to a group of disorders characterized by SNCA/α-synuclein (α-Syn)-containing cytoplasmic inclusions and neuronal cell loss in the nervous system including the cortex, a common feature being cognitive impairment. Still, the molecular pathogenesis of cognitive decline remains poorly understood, hampering the development of effective treatments. Here, we generated induced pluripotent stem cells (iPSCs) derived from familial Parkinson's disease (PD) patients carrying SNCA A53T mutation, differentiating them into cortical neurons by a direct conversion method. Patient iPSCs-derived cortical neurons harboring mutant α-Syn exhibited increased α-Syn-positive aggregates, shorter neurites, and time-dependent vulnerability. Furthermore, RNA-sequencing analysis, followed by biochemical validation, identified the activation of the ERK1/2 and JNK cascades in cortical neurons with SNCA A53T mutation. This result was consistent with a reverted phenotype of neuronal death in cortical neurons when treated with ERK1/2 and JNK inhibitors, respectively. Our findings emphasize the role of ERK1/2 and JNK cascades in the vulnerability of cortical neurons in synucleinopathies, and they could pave the way toward therapeutic advancements for synucleinopathies.

One-step induction of photoreceptor-like cells from human iPSCs by delivering transcription factors.

Retinal dystrophies (RDs) lead to irreversible vision impairment with no radical treatment. Although photoreceptor cells (PRCs) differentiated from human induced pluripotent stem cells (iPSCs) are essential for the study of RDs as a scalable source, current differentiation methods for PRCs require multiple steps. To address these issues, we developed a method to generate PRCs from human iPSCs by introducing the transcription factors, CRX and NEUROD1. This approach enabled us to generate induced photoreceptor-like cells (iPRCs) expressing PRC markers. Single-cell RNA sequencing revealed the transcriptome of iPRCs in which the genes associated with phototransduction were expressed. Generated iPRCs exhibited their functional properties in calcium imaging. Furthermore, light-induced damage on iPRCs was inhibited by an antioxidant compound. This simple approach would facilitate the availability of materials for PRC-related research and provide a useful application for disease modeling and drug discovery.

Establishment of induced pluripotent stem cells from schizophrenia discordant fraternal twins.

Schizophrenia (SCZ) is one of the major psychiatric disorders. The genetic factor is certainly influential in the onset of the disease but is not decisive. There is no identified molecular/cellular marker of the disease, and the pathomechanism is still unknown. In this study, we generated human induced pluripotent stem cells (iPSCs) derived from SCZ-discordant fraternal twins, and they could contribute to elucidation of the pathomechanism of SCZ.

iPSC screening for drug repurposing identifies anti-RNA virus agents modulating host cell susceptibility.

Human pathogenic RNA viruses are threats to public health because they are prone to escaping the human immune system through mutations of genomic RNA, thereby causing local outbreaks and global pandemics of emerging or re-emerging viral diseases. While specific therapeutics and vaccines are being developed, a broad-spectrum therapeutic agent for RNA viruses would be beneficial for targeting newly emerging and mutated RNA viruses. In this study, we conducted a screen of repurposed drugs using Sendai virus (an RNA virus of the family Paramyxoviridae), with human-induced pluripotent stem cells (iPSCs) to explore existing drugs that may present anti-RNA viral activity. Selected hit compounds were evaluated for their efficacy against two important human pathogens: Ebola virus (EBOV) using Huh7 cells and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using Vero E6 cells. Selective estrogen receptor modulators (SERMs), including raloxifene, exhibited antiviral activities against EBOV and SARS-CoV-2. Pioglitazone, a PPARγ agonist, also exhibited antiviral activities against SARS-CoV-2, and both raloxifene and pioglitazone presented a synergistic antiviral effect. Finally, we demonstrated that SERMs blocked entry steps of SARS-CoV-2 into host cells. These findings suggest that the identified FDA-approved drugs can modulate host cell susceptibility against RNA viruses.

Human induced pluripotent stem cells generated from a patient with idiopathic basal ganglia calcification.

Idiopathic basal ganglia calcification (IBGC) is a rare neurodegenerative disease, characterized by abnormal calcium deposits in basal ganglia of the brain. The affected individuals exhibit movement disorders, and progressive deterioration of cognitive and psychiatric ability. The genetic cause of the disease is mutation in one of several different genes, SLC20A2, PDGFB, PDGFRB, XPR1 or MYORG, which inheritably or sporadically occurs. Here we generated an induced pluripotent stem cell (iPSC) line from an IBGC patient, which is likely be a powerful tool for revealing the pathomechanisms and exploring potential therapeutic candidates of IBGC.

Generation of a human induced pluripotent stem cell line, BRCi009-A, derived from a patient with glycogen storage disease type 1a.

Glycogen storage disease type 1a (GSD1a) is an autosomal recessive disorder caused by mutations of the glucose-6-phosphatase (G6PC) gene. Mutations of the G6PC gene lead to excessive accumulation of glycogen in the liver, kidney, and intestinal mucosa due to the deficiency of microsomal glucose-6-phosphatase. Human induced pluripotent stem cells (iPSCs) enable the production of patient-derived hepatocytes in culture and are therefore a promising tool for modeling GSD1a. Here, we report the establishment of human iPSCs from a GSD1a patient carrying a G6PC mutation (c.648G > T; p.Leu216 = ).

Generation of a human induced pluripotent stem cell line derived from a Parkinson's disease patient carrying SNCA duplication.

Parkinson's disease (PD) is a devastating movement disorder with an unknown etiology. Multiplications of the SNCA gene cause the autosomal dominant form of familial PD as well as missense mutations of the gene. We established and characterized a human induced pluripotent stem cell (iPSC) line from a PD patient carrying SNCA duplication. The iPSC line displayed a capacity to differentiate into midbrain dopaminergic neurons affected in PD. The iPSC line will be useful for disease modeling applications.

Generation of a human induced pluripotent stem cell line, BRCi005-A, derived from a Best disease patient with BEST1 mutations.

Best Disease is an inherited retinal dystrophy that results in progressive and irreversible central vision loss caused by mutations of BESTROPHIN1 (BEST1). We established human induced pluripotent stem cells (iPSCs) from a Best disease patient with mutations R218H and A357V in the BEST1 gene. The generated iPSCs showed pluripotency markers and three-germ layer differentiation ability in vitro. A genetic analysis revealed mutations of R218H and A357V in the iPSCs. This iPSC line will be useful for elucidating the pathomechanisms of and drug discovery for Best disease.

Generation of a human induced pluripotent stem cell line, BRCi004-A, derived from a patient with age-related macular degeneration.

Age-related macular degeneration (AMD) is a late-onset progressive blinding disease. We established human induced pluripotent stem cells (iPSCs) from an AMD patient. The generated iPSC line showed pluripotency markers and three-germ layer differentiation ability in vitro. This iPSC line will be useful for elucidating the pathomechanisms of and drug discovery for AMD.

Generation of a human induced pluripotent stem cell line, BRCi001-A, derived from a patient with mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPS I) is a rare inherited metabolic disorder caused by defects in alpha-L-iduronidase (IDUA), a lysosomal protein encoded by IDUA gene. MPS I is a progressive multisystemic disorder with a wide range of symptoms, including skeletal abnormalities and cognitive impairment, and is characterized by a wide spectrum of severity levels caused by varied mutations in IDUA. A human iPSC line was established from an attenuated MPS I (Scheie syndrome) patient carrying an IDUA gene mutation (c.266G > A; p.R89Q). This disease-specific iPSC line will be useful for the research of MPS I.

Induced pluripotent stem cells derived from an autosomal dominant lateral temporal epilepsy (ADLTE) patient carrying S473L mutation in leucine-rich glioma inactivated 1 (LGI1).

Autosomal dominant lateral temporal epilepsy (ADLTE) is an inherited epileptic syndrome, and it is associated with mutations of leucine-rich glioma inactivated 1 (LGI1) gene. The underlying mechanisms of ADLTE are still unknown, as human neurons are difficult to obtain as a research tool. Human induced pluripotent stem cells (iPSCs) allow the generation of patient-derived neuronal cells in a dish, and can be a promising tool to model ADLTE. Here, we report the establishment of human iPSCs from an ADLTE patient carrying LGI1 mutation (c.1418C>T, p.Ser473Leu).

Establishment of DYT5 patient-specific induced pluripotent stem cells with a GCH1 mutation.

Peripheral blood mononuclear cells (PBMCs) were collected from a clinically diagnosed 20-year-old dystonia patient with a GCH1 mutation (DYT5). Episomal vectors were used to introduce reprogramming factors (OCT3/4, SOX2, KLF4, L-MYC, LIN28, and p53 carboxy-terminal dominant-negative fragment) to the PBMCs. The generated iPSCs expressed pluripotency markers, and were capable of differentiating into derivates of all three germ layers in vitro. The iPSC line also showed a normal karyotype and preserved the GCH1 mutation. This cellular model can provide opportunities to perform pathophysiological studies for aberrant dopamine metabolism-related disorders.

Induced pluripotent stem cells derived from a patient with familial idiopathic basal ganglia calcification (IBGC) caused by a mutation in SLC20A2 gene.

Idiopathic basal ganglia calcification (IBGC), also known as Fahr disease or primary familial brain calcifications (PFBC), is a rare neurodegenerative disorder characterized by calcium deposits in basal ganglia and other brain regions, causing neuropsychiatric and motor symptoms. We established human induced pluripotent stem cells (iPSCs) from an IBGC patient. The established IBGC-iPSCs carried SLC20A2 c.1848G>A mutation (p.W616* of translated protein PiT2), and also showed typical iPSC morphology, pluripotency markers, normal karyotype, and the ability of in vitro differentiation into three-germ layers. The iPSC line will be useful for further elucidating the pathomechanism and/or drug development for IBGC.

Analysis of neural crest cells from Charcot-Marie-Tooth disease patients demonstrates disease-relevant molecular signature.

Charcot-Marie-Tooth disease (CMT) is the most common inherited neuropathy. The majority of CMT is demyelinating type (demyelinating CMT) caused by Schwann cell involvement. Although a large number of genes responsible for demyelinating CMT have been found, the common molecular target of the pathophysiology caused by these different genes in demyelinating CMT is still unknown. We generated induced pluripotent stem cells (iPSCs) from healthy controls and patients with demyelinating CMT caused by duplication in peripheral myelin protein 22 kDa (PMP22) or point mutations in myelin protein zero (MPZ) or early growth response 2 (EGR2). iPSCs were differentiated into neural crest cells, progenitors of Schwann cells, followed by purification using the neural crest cell markers p75 and human natural killer-1. To identify a disease-relevant molecular signature at the early stage of demyelinating CMT, we conducted global gene expression analysis of iPSC-derived neural crest cells and found that a glutathione-mediated detoxification pathway was one of the related pathways in demyelinating CMT. mRNA expression of glutathione S-transferase theta 2 (GSTT2), encoding an important enzyme for glutathione-mediated detoxification, and production of reactive oxygen species were increased in demyelinating CMT. Our study suggested that patient-iPSC-derived neural crest cells could be a cellular model for investigating genetically heterogeneous disease CMT and might provide a therapeutic target for the disease.

Direct reprogramming of somatic cells is promoted by maternal transcription factor Glis1.

Induced pluripotent stem cells (iPSCs) are generated from somatic cells by the transgenic expression of three transcription factors collectively called OSK: Oct3/4 (also called Pou5f1), Sox2 and Klf4. However, the conversion to iPSCs is inefficient. The proto-oncogene Myc enhances the efficiency of iPSC generation by OSK but it also increases the tumorigenicity of the resulting iPSCs. Here we show that the Gli-like transcription factor Glis1 (Glis family zinc finger 1) markedly enhances the generation of iPSCs from both mouse and human fibroblasts when it is expressed together with OSK. Mouse iPSCs generated using this combination of transcription factors can form germline-competent chimaeras. Glis1 is enriched in unfertilized oocytes and in embryos at the one-cell stage. DNA microarray analyses show that Glis1 promotes multiple pro-reprogramming pathways, including Myc, Nanog, Lin28, Wnt, Essrb and the mesenchymal-epithelial transition. These results therefore show that Glis1 effectively promotes the direct reprogramming of somatic cells during iPSC generation.