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Trastuzumab-induced cardiotoxicity interferes with continued treatment in approximately 10% of patients with ErbB2-positive breast cancer, but its mechanism has not been fully elucidated. In this study, we recruited trastuzumab-treated patients with ≥30% reduction in left ventricular ejection fraction (SP) and noncardiotoxic patients (NP). From each of these patients, we established three cases of induced pluripotent stem cell-derived cardiomyocytes (pt-iPSC-CMs). Reduced contraction and relaxation velocities following trastuzumab treatment were more evident in SP pt-iPSC-CMs than NP pt-iPSC-CMs, indicating the cardiotoxicity phenotype could be replicated. Differences in ATP production, reactive oxygen species, and autophagy activity were observed between the two groups. Analysis of transcripts revealed enhanced kallikrein5 expression and pro-inflammatory signaling pathways, such as interleukin-1β, in SP pt-iPSC-CMs after trastuzumab treatment. The kallilkrein5-protease-activated receptor 2 (PAR2)-MAPK signaling pathway was more activated in SP pt-iPSC-CMs, and treatment with a PAR2-antagonist suppressed interleukin-1β expression. Our data indicate enhanced pro-inflammatory responses through kallikrein5-PAR2 signaling and vulnerability to external stresses appear to be the cause of trastuzumab-induced cardiotoxicity in SP.

The serotonin 5-HT2A receptor (5-HT2AR) has been receiving increasing attention because its genetic variants have been associated with a variety of neurological diseases. To elucidate the pathogenesis of the neurological diseases associated with 5-HT2AR gene (HTR2A) variants, we have previously established a protocol to induce HTR2A-expressing neurons from human-induced pluripotent stem cells (hiPSCs). Here, we investigated the maturation stages and electrophysiological properties of HTR2A-positive neurons induced from hiPSCs and constructed an HTR2A promoter-specific reporter lentivirus to label the neurons. We found that neuronal maturity increased over time and that HTR2A expression was induced at the late stage of neuronal maturation. Furthermore, we demonstrated successful labelling of the HTR2A-positive neurons, which had fluorescence and generated repetitive action potentials in response to depolarizing currents and an inward current during the application of TCB-2, a selective agonist of 5-HT2ARs, respectively. These results indicated that our in vitro model mimicked the in vivo dynamics of 5-HT2AR. Therefore, in vitro monitoring of the function of HTR2A-positive neurons induced from hiPSCs could help elucidate the pathophysiological mechanisms of neurological diseases associated with genetic variations of the HTR2A gene.

Mitochondrial structural changes are associated with the regulation of mitochondrial function, apoptosis, and neurodegenerative diseases. PRKN is known to be involved with various mechanisms of mitochondrial quality control including mitochondrial structural changes. Parkinson’s disease (PD) with PRKN mutations is characterized by the preferential degeneration of dopaminergic neurons in the substantia nigra pars compacta, which has been suggested to result from the accumulation of damaged mitochondria. However, ultrastructural changes of mitochondria specifically in dopaminergic neurons derived from iPSC have rarely been analyzed. The main reason for this would be that the dopaminergic neurons cannot be distinguished directly among a mixture of iPSC-derived differentiated cells under electron microscopy. To selectively label dopaminergic neurons and analyze mitochondrial morphology at the ultrastructural level, we generated control and PRKN-mutated patient tyrosine hydroxylase reporter (TH-GFP) induced pluripotent stem cell (iPSC) lines. Correlative light-electron microscopy analysis and live cell imaging of GFP-expressing dopaminergic neurons indicated that iPSC-derived dopaminergic neurons had smaller and less functional mitochondria than those in non-dopaminergic neurons. Furthermore, the formation of spheroid-shaped mitochondria, which was induced in control dopaminergic neurons by a mitochondrial uncoupler, was inhibited in the PRKN-mutated dopaminergic neurons. These results indicate that our established TH-GFP iPSC lines are useful for characterizing mitochondrial morphology, such as spheroid-shaped mitochondria, in dopaminergic neurons among a mixture of various cell types. Our in vitro model would provide insights into the vulnerability of dopaminergic neurons and the processes leading to the preferential loss of dopaminergic neurons in patients with PRKN mutations.

The gap junction beta-2 (GJB2) gene is the most common genetic cause of hereditary deafness worldwide. Among them, the G45E/Y136X mutation in GJB2 is the third most prevalent in Japan. In this study, we generated two induced pluripotent stem cell (iPSC) lines from peripheral blood mononuclear cells (PBMCs) of siblings with moderate-to-severe hearing loss (patient) or normal hearing (genetic carrier) carrying a homozygous or heterozygous G45E/Y136X mutation in GJB2 gene, respectively. These iPSC lines showed the expression of pluripotency markers and could differentiate into three germ layers. These disease-specific iPSC lines will be a powerful tool for investigating the pathogenesis of GJB2-related deafness.

Sleep bruxism (SB) is a sleep-related movement disorder characterized by grinding and clenching of the teeth during sleep. We previously found a significant association between SB and a single nucleotide polymorphism (SNP), rs6313, in the neuronal serotonin 2A receptor gene (HTR2A), and established human induced pluripotent stem cell (hiPSC)-derived neurons from SB patients with a genetic variant. To elucidate the electrophysiological characteristics of SB iPSC-derived neural cells bearing a SB-related genetic variant, we generated ventral hindbrain neurons from two SB patients and two unaffected controls and explored the intrinsic membrane properties of these neurons by patch-clamp technique. We found that the electrophysiological properties of the iPSC-derived neurons from the control line mature in a time-dependent manner in long-term cultures. In the early stage of neurogenesis, neurons from two SB lines tended to display shorter action potential (AP) half durations, which led to an increased cell capability of evoked firing. This is the first in vitro modelling of SB using disease-specific hiPSCs. The revealed electrophysiological characteristics may serve as a benchmark for further investigation of pathogenic mechanisms underlying SB.Summary StatementSleep bruxism patient-specific iPSC-derived neurons with the HTR2A variant show altered electrophysiological characteristics, providing the foremost narration of sleep bruxism neurological phenotypes in vitro from any species.

Sleep bruxism (SB) is a sleep-related movement disorder characterized by grinding and clenching of the teeth during sleep. We previously found a significant association between SB and a single nucleotide polymorphism (SNP), rs6313, in the neuronal serotonin 2A receptor gene (HTR2A) and established human induced pluripotent stem cell (iPSC)-derived neurons from SB patients with a genetic variant. To elucidate the electrophysiological characteristics of SB iPSC-derived neural cells bearing an SB-related genetic variant, we generated ventral hindbrain neurons from SB patients and unaffected controls and explored the intrinsic membrane properties of these neurons by the patch-clamp technique. We found that the electrophysiological properties of iPSC-derived neurons mature in a time-dependent manner in long-term control cultures. SB neurons exhibited shorter action potential half durations and higher action potential firing frequencies. This is the first in vitro modeling of SB using patient-specific iPSCs. The revealed electrophysiological characteristics may serve as a benchmark for further investigation of pathogenic mechanisms underlying SB. Moreover, our results on long-term cultures provide a strategy to define functional maturity of human neurons in vitro, which can be implemented for stem cell research of neurogenesis, and neurodevelopmental disorders.

Summary Although pluripotent stem cells can generate various types of differentiated cells, it is unclear why lineage-committed stem/progenitor cells derived from pluripotent stem cells are decelerated and why the differentiation-resistant propensity of embryonic stem cell (ESC)/induced pluripotent stem cell (iPSC)-derived cells is predominant compared with the in vivo equivalents derived from embryonic/adult tissues. In this study, we demonstrated that iPSCs reprogrammed and maintained with three chemical inhibitors of the fibroblast growth factor 4-mitogen-activated protein kinase cascade and GSK3β (3i) could be differentiated into all three germ layers more efficiently than the iPSCs reprogrammed without the 3i chemicals, even though they were maintained with 3i chemicals once they were reprogrammed. Although the iPSCs reprogrammed with 3i had increased numbers of Zscan4-positive cells, the Zscan4-positive cells among iPSCs that were reprogrammed without 3i did not have an accelerated differentiation ability. These observations suggest that 3i exposure during the reprogramming period determines the accelerated differentiation/maturation potentials of iPSCs that are stably maintained at the distinct state., Graphical Abstract, Highlights • iPSCs reprogrammed and maintained with 3i have accelerated differentiation potential • iPSC colonies reprogrammed with 3i contain increased number of Zscan4 (+) cells, Mouse iPSCs reprogrammed and maintained with three chemical inhibitors of the FGF4-MAPK cascade and GSK3β (3i; PD184352, CHIR99021, and SU5402) could be differentiated into all three germ layers efficiently and contain increased numbers of Zscan4, a 2-cell stage marker, positive cells.

Parkinson’s disease (PD) is characterized by the loss of A9 midbrain dopaminergic neurons and the accumulation of alpha-synuclein aggregates in remaining neurons. Many studies of the molecular and cellular basis of neurodegeneration in PD have made use of iPSC-derived neurons from patients with familial PD mutations. However, approximately half of the cells in the brain are glia, and their role facilitating neurodegeneration is unclear. We developed a novel serum-free protocol to generate midbrain astrocytes from patient-derived iPSCs harbouring the pathogenic p.A30P, p.A53T mutations inSNCA, as well as duplication and triplication of theSNCAlocus. In our cellular model, aggregates of alpha-synuclein occurred only within the GFAP+astrocytes carrying the pathogenicSNCAmutations. Assessment of spontaneous cytosolic calcium (Ca2+) release using Fluo4 revealed thatSNCAmutant astrocytes released excess Ca2+compared to controls. Unbiased evaluation of 3D mitochondrial morphometric parameters showed that theseSNCAmutant astrocytes had increased mitochondrial fragmentation and decreased mitochondrial connectivity compared to controls, and reduced mitochondrial bioenergetic function. This comprehensive assessment of different pathogenicSNCAmutations derived from PD patients using the same cellular model enabled assessment of the mutation effect, showing that p.A53T and triplication astrocytes were the most severely affected. Together, our results indicate that astrocytes harbouring the familial PD mutations inSNCAare dysfunctional, suggesting a contributory role for dysfunctional astrocytes in the disease mechanism and pathogenesis of PD.Table of Contents ImageMain PointsWe used a novel serum-free protocol to generate midbrain-specific functional astrocytes from Parkinson’s disease patients carrying pathological mutations inSNCAPatient-derived astrocytes show morphological and functional impairments

Vitamin B12 deficiency is a risk factor for bone disorders via mechanisms not fully understood. In this study, an increase in serum inorganic phosphorus (Pi) concentrations was associated with a vitamin B12 deficiency. Napi2a, a renal cotransporter for Pi reabsorption, accumulated on plasma membranes in a vitamin B12 deficiency suggests that vitamin B12 plays an important role in Pi homeostasis.

Megalin is a scavenger receptor that serves in the endocytosis of a highly diverse group of ligands that includes Vitamin B12. We found an accumulation of megalin closed to apical region in renal proximal tubule cells of Vitamin B12-deficient rats. Interestingly, Vitamin B12 levels also controlled resorption of renal retinol binding protein. Using L2 yolk sac cells, megalin localized to the submembrane compartment by methylmalonic acid (MMA), which accumulates during vitamin B12 deficiency. In addition, MMA inhibited megalin-mediated endocytosis via YWTD repeats motif in an ectodomain of megalin. Therefore, megalin endocytosis may be regulated by MMA.

Vitamin B12 deficiency is a risk factor for bone disorders via mechanisms not fully understood. In this study, an increase in serum inorganic phosphorus (Pi) concentrations was associated with a vitamin B12 deficiency. Napi2a, a renal cotransporter for Pi reabsorption, accumulated on plasma membranes in a vitamin B12 deficiency suggests that vitamin B12 plays an important role in Pi homeostasis.

As a general hospital that is aiming to provide regional medical care, our hospital has been actively involved in trying to establish a unified system for providing information on drugs to patients, through close cooperation with the Regional Pharmacists Association. We have been involved in promoting the spread of prescriptions to be filled at outside phrmacies, training pharmacists working in pharmacies, and providing information on drugs to patients through the issuance of a “medicine guidebook” and “drug-record pocketbook”, and thus have established a system for exchanging of information on drugs in order to monitor the side effects in patients, and thereby establish a system to exchange information among patients treated at home. The results of our efforts in these areas have indicated that, hospital pharmacists, in cooperation with pharmacists working at pharmacies, can therefore partitively contribute to the treatment of outpatients and to regional medical care.

As a general hospital that plays a supporting role in regional medical care, our hospital has been addressing the problems regarding the “Study Project for Cooperation Between Pharmacies in Medical Institutions Offering Home Medical Care and Private Pharmacies” initiated by the Ministry of Health and Welfare in 1997. In this cooperative system, efforts have been made by hospital pharmacists and private pharmacists to interlink such systems as the system for instructing patients being discharged regarding their medications and the delivery system. In this regard there has been an increased exchange of information between pharmacists on patients requiring medical care at home. This system of cooperation between hospital and private pharmacists in home medical care is thought to be an effective way to improve the quality of treatment, and thereby enhane the quality of life for such patients.

Mistakes in filling prescriptions at outside pharmacies can sometimes lead to hospitalization, especially in the case of children. To counter this problem, we began to issue a “drug-record poketbook” to provide information to pharmacies and to educate the parents. We developed a system for drug management guidance in pediatrics aimed at improving the quality of guidance for medication. This system makes use of TDM, allows the participation in doctors' rounds, and provides pamphlets explaining certain points that the potients need to be careful about. After the introduction of this system, the number of dispensing errors at pharmacies decreased. This comprehensive information system enabled the monitoring of both inpatients as well as outpatients. These results show this system is a useful contribution to the service for patients.

Quasielastic neutron scattering measurements were carried out at room temperature for liquid S 2 Cl 2 , S 2 Br 2 , Se 2 Cl 2 and Se 2 Br 2 , which are composed of the molecules having the X-A-A-X type chain unit, X and A being halogen and chalcogen atoms. The measurements were performed at the scattering wave vectors of 0.98, 1.55, 2.32 and 2.66 A -1 by using AGNES spectrometer installed in JAERI. By analyzing the intermediate scattering function, which was obtained by Fourier transform of the observed dynamic structure factor, a fast and a slow relaxation processes have been found. The fast process, whose relaxation time is less than 1 picosecond, may be assigned to fluctuations in the dihedral angle within the molecule, while the slow process, whose relaxation time depends strongly on the molecular weight, may be assigned to the translational diffusion of the molecule.