Jun Takahashi

Kyoto University, Kioto, Kyōto, Japan

Are you Jun Takahashi?

Claim your profile

Publications (159)554.05 Total impact

  • Source
    Kaneyasu Nishimura · Shigeo Murayama · Jun Takahashi
    [Show abstract] [Hide abstract]
    ABSTRACT: Successful cell transplantation for Parkinson's disease (PD) depends on both an optimal host brain environment and ideal donor cells. We report that a secreted peptide, neurexophilin 3 (NXPH3), supports the survival of mouse induced pluripotent stem cell-derived (iPSC-derived) dopaminergic (DA) neurons in vitro and in vivo. We compared the gene expression profiles in the mouse striatum from two different environments: a supportive environment, which we defined as 1 week after acute administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and a nonsupportive environment, defined as 8 weeks after chronic administration of MPTP. NXPH3 expression was higher in the former condition and lower in the latter compared with untreated controls. When we injected mouse iPSC-derived neural cells along with NXPH3 into the mouse striatum, the ratio of tyrosine hydroxylase-positive DA neurons per graft volume was higher at 8 weeks compared with cell injections that excluded NXPH3. In addition, quantitative polymerase chain reaction analyses of the postmortem putamen revealed that the expression level of NXPH3 was lower in PD patients compared with normal controls. These findings will contribute to optimizing the host brain environment and patient recruitment in cell therapy for PD. ©AlphaMed Press.
    STEM CELLS TRANSLATIONAL MEDICINE 06/2015; DOI:10.5966/sctm.2014-0197 · 3.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We aimed at evaluating the infective complications with intracranial EEG recording in order to lessen them. We retrospectively reviewed our database of intracranial monitoring cases with subdural electrodes at Kyoto University Hospital between May 1992 and March 2012. A total of 46 monitoring sessions were included in this analysis. Infective complications related to intracranial electrodes occurred in four monitoring sessions (8.7%) (three male patients). Causative agents were identified as Staphylococcus aureus (S. aureus) in three monitoring sessions and Staphylococcus epidermidis in one. In univariate analysis, the significant risk factor was solely identified as the season of monitoring. More infective complications occurred when the monitoring took place in autumn. There tended to be more infective complications in the cases, who had implantation in the right side or discontinuation of intravenously administered prophylactic antibiotics although these factors were not statistically significant. Age, gender, duration of monitoring, number of electrodes, and pathological diagnosis did not seem to represent an increased risk of infective complications. Infective complications had no significant influence on seizure outcome. Invasive monitoring during autumn might be a risk factor especially in terms of infective complications. S. aureus was a common pathogen. Copyright © 2015 Elsevier Inc. All rights reserved.
    World Neurosurgery 03/2015; DOI:10.1016/j.wneu.2015.03.048 · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by mutations of the survival of motor neuron 1 (SMN1) gene. In the pathogenesis of SMA, pathological changes of the neuromuscular junction (NMJ) precede the motor neuronal loss. Therefore, it is critical to evaluate the NMJ formed by SMA patients' motor neurons (MNs), and to identify drugs that can restore the normal condition. We generated NMJ-like structures using MNs derived from SMA patient-specific induced pluripotent stem cells (iPSCs), and found that the clustering of the acetylcholine receptor (AChR) is significantly impaired. Valproic acid and antisense oligonucleotide treatment ameliorated the AChR clustering defects, leading to an increase in the level of full-length SMN transcripts. Thus, the current in vitro model of AChR clustering using SMA patient-derived iPSCs is useful to dissect the pathophysiological mechanisms underlying the development of SMA, and to evaluate the efficacy of new therapeutic approaches. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Stem Cell Reports 03/2015; 4(4). DOI:10.1016/j.stemcr.2015.02.010 · 5.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the in vivo function of human dopaminergic (DA) neurons, Parkinson's disease (PD) model rats made by the hemi-lateral injection of 6-hydroxydopamine (6-OHDA) are widely used as host animals. In the case of such xeno-transplantation, however, immunosuppression is needed for good survival of the grafted cells.
    Journal of Neuroscience Methods 02/2015; 243. DOI:10.1016/j.jneumeth.2015.01.027 · 1.96 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Survivors of pediatric brain tumors are often affected by late effects, such as motility disturbance of limb(s), seizure, ocular/visual impairment, endocrine abnormality, and higher brain dysfunction, resulting from the disease and its treatment. Appropriate provision of supportive care will require understanding the effects of these experiences on survivors' health-related quality of life (HRQOL). The aim of this study was to identify the relationships between late effects and specific aspects of the HRQOL of pediatric brain tumor survivors. We distributed questionnaires for measuring HRQOL to 138 survivors and their parents at 8 hospitals and 1 clinic in Japan and simultaneously surveyed late effects using information provided by the survivors' attending physicians. We compared the HRQOL of survivors with and survivors without specific late effects. A total of 106 survivors and their parents returned the questionnaires to the researchers. The HRQOL of survivors 18 years or older was negatively affected by all 5 late effects, indicating that their higher impairment was associated with diminished HRQOL. The HRQOL of survivors aged 12 to 17 years was negatively affected by 2 late effects (ocular/visual impairment and motility disturbance of the limbs). A part of the HRQOL subdomain (motor and cognitive functioning) of survivors aged 12 to 17 years was positively related to ocular/visual impairment. Five late effects influenced the HRQOL of pediatric brain tumor survivors. Nurses and other health professionals should provide specific care designed to support aspects of HRQOL affected by late effects. For example, survivors with ocular/visual impairment may be expected to require additional emotional support, and those with seizures or endocrine abnormalities may be expected to require additional support for sleep disorders.
    Cancer nursing 03/2014; 37(6). DOI:10.1097/NCC.0000000000000110 · 1.93 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Human induced pluripotent stem cells (iPSCs) can provide a promising source of midbrain dopaminergic (DA) neurons for cell replacement therapy for Parkinson's disease. However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. Here, we show that human iPSC-derived DA progenitor cells can be efficiently isolated by cell sorting using a floor plate marker, CORIN. We induced DA neurons using scalable culture conditions on human laminin fragment, and the sorted CORIN(+) cells expressed the midbrain DA progenitor markers, FOXA2 and LMX1A. When transplanted into 6-OHDA-lesioned rats, the CORIN(+) cells survived and differentiated into midbrain DA neurons in vivo, resulting in significant improvement of the motor behavior, without tumor formation. In particular, the CORIN(+) cells in a NURR1(+) cell-dominant stage exhibited the best survival and function as DA neurons. Our method is a favorable strategy in terms of scalability, safety, and efficiency and may be advantageous for clinical application.
    Stem Cell Reports 03/2014; 2(3):337-50. DOI:10.1016/j.stemcr.2014.01.013 · 5.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to apply human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) to regenerative medicine, the cells should be produced under restricted conditions conforming to GMP guidelines. Since the conventional culture system has some issues that need to be addressed to achieve this goal, we developed a novel culture system. We found that recombinant laminin-511 E8 fragments are useful matrices for maintaining hESCs and hiPSCs when used in combination with a completely xeno-free (Xf) medium, StemFit™. Using this system, hESCs and hiPSCs can be easily and stably passaged by dissociating the cells into single cells for long periods, without any karyotype abnormalities. Human iPSCs could be generated under feeder-free (Ff) and Xf culture systems from human primary fibroblasts and blood cells, and they possessed differentiation abilities. These results indicate that hiPSCs can be generated and maintained under this novel Ff and Xf culture system.
    Scientific Reports 01/2014; 4:3594. DOI:10.1038/srep03594 · 5.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We examined the gene expression and DNA methylation of 49 human induced pluripotent stem cells (hiPSCs) and 10 human embryonic stem cells and found overlapped variations in gene expression and DNA methylation in the two types of human pluripotent stem cell lines. Comparisons of the in vitro neural differentiation of 40 hiPSCs and 10 human embryonic stem cells showed that seven hiPSC clones retained a significant number of undifferentiated cells even after neural differentiation culture and formed teratoma when transplanted into mouse brains. These differentiation-defective hiPSC clones were marked by higher expression levels of several genes, including those expressed from long terminal repeats of specific human endogenous retroviruses. These data demonstrated a subset of hiPSC lines that have aberrant gene expression and defective potential in neural differentiation, which need to be identified and eliminated before applications in regenerative medicine.
    Proceedings of the National Academy of Sciences 11/2013; 110(51). DOI:10.1073/pnas.1319061110 · 9.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Surgical intervention is expected to improve the quality of life in patients with intractable epilepsy by providing adequate seizure control. Although many previous studies showed various rates of seizure freedom, definite conclusions have not yet been made regarding outcomes. In order to clarify the long-term postoperative outcome for a period up to 10 years, a retrospective review of our patients was performed longitudinally by using the survival analysis method. The postoperative state of epilepsy in 76 patients who underwent resection surgery was assessed based on Engel's criteria. In addition, Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. In this patient group, abnormal lesion were detected by MRI in 70 out of 76 cases, and the ictal onset zone was finally identified within temporal lobe in 51 cases. The most favorable outcome, defined as Engel Class Ia, was observed in 26 (37%), 24 (40%), and 18 (41%) cases at 2, 5, and 10 years after surgery, respectively. The Kaplan-Meier survival curve in the overall group estimated the probability of seizure freedom as 75% (95% confidence interval [CI] 70-80%), 67% (62-72%), and 51% (45-57%) at 2, 5, and 10 years follow up, respectively. Half of all seizure recurrences occurred within the first 2 postoperative years. In this study, we showed that long-term favorable outcome of seizure control following resection surgery can be achieved in more than half of the patients.
    Neurologia medico-chirurgica 10/2013; 53(11). DOI:10.2176/nmc.oa2013-0065 · 0.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Induced pluripotent stem cells (iPSCs) provide the potential for autologous transplantation using cells derived from a patient's own cells. However, the immunogenicity of iPSCs or their derivatives has been a matter of controversy, and up to now there has been no direct comparison of autologous and allogeneic transplantation in the brains of humans or nonhuman primates. Here, using nonhuman primates, we found that the autologous transplantation of iPSC-derived neurons elicited only a minimal immune response in the brain. In contrast, the allografts caused an acquired immune response with the activation of microglia (IBA-1(+)/MHC class II(+)) and the infiltration of leukocytes (CD45(+)/CD3(+)). Consequently, a higher number of dopaminergic neurons survived in the autografts. Our results suggest that the autologous transplantation of iPSC-derived neural cells is advantageous for minimizing the immune response in the brain compared with allogeneic grafts.
    Stem Cell Reports 10/2013; 1(4):283-292. DOI:10.1016/j.stemcr.2013.08.007 · 5.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Our work and the study of Bilican et al. highlight the need for complementary assays to detect subtle phenotypic differences between control and mutant induced pluripotent stem cell lines.
    Science translational medicine 06/2013; 5(188):188lr2. DOI:10.1126/scitranslmed.3005697 · 14.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aim: The aim of this study was to determine the correlation between the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) axis and glucose intolerance in acromegaly during the early postoperative period. Subjects and Methods: The study included 20 patients with acromegaly caused by GH-secreting pituitary adenoma who received transsphenoidal surgery in our hospital. Glucose tolerance was evaluated with oral glucose tolerance tests (OGTTs) performed pre- and early postoperative periods (9 [7-18] days after surgery). Homeostasis model assessment of insulin resistance (HOMA-R) and insulinogenic index (IGI) were calculated, and correlation analyses were performed between these values and the GH- IGF-1 axis. Patients were divided according to postoperative changes of the axis, and glucose tolerance was compared between the groups. Results: In preoperative OGTTs, nine patients had impaired glucose tolerance and two had diabetes mellitus patterns. Postoperatively, significant reduction was observed both in fasting plasma glucose levels (p < 0.01) and in HOMA-R (p < 0.01), whereas IGI showed no significant change. HOMA-R was significantly correlated with serum IGF-1 levels both before (r = 0.83, p < 0.01) and after (r = 0.57, p < 0.01) surgery, although it was not correlated with serum GH levels. Patients who achieved more than 50% postoperative reduction in serum IGF-1 levels showed significant improvement in OGTTs results (p < 0.05). Conclusions: In patients with acromegaly, serum IGF-1 levels, but not GH levels, were significantly correlated with insulin resistance. Early postoperative improvement of glucose tolerance is observed in patients who achieved postoperative reduction in serum IGF-1 levels.
    Journal of endocrinological investigation 05/2013; 36(10). DOI:10.3275/8964 · 1.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Animals that possess regenerative abilities are widespread in the animal kingdom. Hydra, planarian, zebrafish, newt and axolotl are known prominent species, and the cellular aspects of the stem cell system for regeneration are well elucidated. However, few animals can be used to investigate the molecular basis of neuronal regeneration, in spite of the presence of prominent regenerative animals, as mentioned above. Planarians, for instance, can regenerate a functional brain after amputation in a few days, even from non-brain tissue. Newts can regenerate several tissues and organs (i.e., lens, limbs, jaws, hearts and tails) with recovery of function and physiology after injury or tissue removal. These animals achieve regeneration of missing nervous system utilizing stem cells. However, it is difficult to regenerate nervous system in mammalians, including human beings, although these animals possess neural stem cells. Therefore, regenerative animals provide unique opportunities to investigate the generation and utilization of stem cells to repair lost or injured tissue in non-regenerative animals. On the other hand, the successful derivation of neural cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) under in vitro conditions provides a new experimental strategy for clinical translation. In other words, although human beings lack regenerative abilities, the new clinical strategy of “regenerative medicine,” including cell-transplantation therapy, has been developed to recover lost neural functions by using stem cells. This research field has become a greatly advancing scientific field worldwide. In this chapter, we focus on the molecular systems of generation of functional dopaminergic (DA) neurons in vivo and/or in vitro in regenerative and non-regenerative animals. The first topic investigates how regenerative animals recruit new DA neurons from stem cells after injury. The second topic explores how to generate DA neurons from mammalian ESCs and iPSCs under in vitro conditions. The third topic evaluates clinical applications for human neural disease, especially Parkinson’s disease.
    Neural Stem Cells - New Perspectives, Edited by Luca Bonfanti, 04/2013: chapter 10: pages 271-286; InTech., ISBN: 978-953-51-1069-9
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cell replacement therapy using embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) is a promising strategy for the treatment of neurologic diseases such as Parkinson’s disease (PD). However, a limiting factor for effective cell transplantation is the low survival rate of grafted cells, especially neurons. In this study, we modified the host environment and investigated whether the simultaneous administration of soluble factors can improve the survival and differentiation of murine iPSC-derived dopaminergic (DA) neurons in host brains. With the goal of applying this technology in clinical settings in the near future, we selected drugs that were already approved for clinical use. The drugs included two commonly used anticonvulsants, valproic acid (VPA) and zonisamide (ZNS), and estradiol (E2), also known as biologically active estrogen. Following neural induction of murine iPSCs, we collected neural progenitor cells by sorting PSA-NCAM+ cells, then treated the PSA-NCAM+ cells with drugs for four days. An immunofluorescence study revealed that 0.01 mM and 0.1 mM of VPA and 10 nM of E2 increased the percentage of tyrosine hydroxylase+ (TH: a DA neuron marker) cells in vitro. Furthermore, 0.1 mM of VPA increased the percentage of TH+ cells that simultaneously express the midbrain markers FOXA2 and NURR1. Next, in order to determine the effects of the drugs in vivo, the iPSC-derived NPCs were transplanted into the striata of intact SD rats. The animals received intraperitoneal injections of one of the drugs for four weeks, then were subjected to an immunofluorescence study. VPA administration (150 mg/kg/daily) increased the number of NeuN+ postmitotic neurons and TH+ DA neurons in the grafts. Furthermore, VPA (150 mg/kg/daily) and ZNS (30 mg/kg/daily) increased the number of TH+FOXA2+ midbrain DA neurons. These results suggest that the systemic administration of VPA and ZNS may improve the efficiency of cell replacement therapy using iPSCs to treat PD.
    Frontiers in Cellular Neuroscience 02/2013; 7:116. DOI:10.3389/fncel.2013.00116 · 4.18 Impact Factor
  • Source
    Kaneyasu Nishimura · Jun Takahashi
    [Show abstract] [Hide abstract]
    ABSTRACT: Parkinson's disease (PD) is one of the candidate diseases for cell transplantation therapy, since successful clinical experiments have accumulated using human fetal tissue grafting for PD patients. Although some grafted PD patients have shown drastic improvements, several issues still remain with regard to using human fetal tissue. This review highlights the recent advances in stem cell technology toward clinical applications using human pluripotent stem cells. In particular, pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells (iPSCs), are the focus as a source of cell transplantation therapy that can be used instead of human fetal tissues. Additionally, efficient methods for stem cell maintenance and differentiation have been developed and improved toward the clinical transition. These advances in the basic technologies have helped accelerate the realization of regenerative medicine. We also review the current topics regarding disease modeling and drug screening using iPSC technology. Finally, we also describe the future prospects of these stem cell research fields toward clinical application.
    Biological & Pharmaceutical Bulletin 02/2013; 36(2):171-175. DOI:10.1248/bpb.b12-00929 · 1.78 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Figure optionsView in workspaceDownload full-size imageDownload as PowerPoint slide
  • [Show abstract] [Hide abstract]
    ABSTRACT: We herein report three cases of gonadotroph adenoma in men (36-72 years of age) presenting with visual impairment and suprasellar masses measuring approximately 20 to 30 mm in diameter. Endocrinological examinations were normal, except for slightly increased follicle stimulating hormone (FSH) levels in two cases. Based on the tentative diagnosis of non-functioning pituitary adenoma, transsphenoidal surgery was performed, which revealed that the tumors consisted of FSH- and LH-positive cells. As gonadotroph adenoma is very common among patients with clinically silent pituitary adenoma, it should be diagnosed using pathological examinations.
    Internal Medicine 01/2013; 52(11):1199-1202. DOI:10.2169/internalmedicine.52.7855 · 0.97 Impact Factor
  • Source
    Asuka Morizane · Daisuke Doi · Jun Takahashi
    [Show abstract] [Hide abstract]
    ABSTRACT: Pluripotent stem cells are promising potential sources for cell replacement therapy and are useful research tools for exploring disease mechanisms. Neural cells are one of the cell types that have been most efficiently differentiated through several established protocols. This chapter describes the feeder-free floating aggregation culture system for the induction of dopaminergic neurons. This method is simple and highly efficient for the production of dopaminergic neurons. It has several advantages for application in clinical usage in comparison to the other protocols using either feeder cells or Matrigel.
    Methods in molecular biology (Clifton, N.J.) 01/2013; 1018:11-9. DOI:10.1007/978-1-62703-444-9_2 · 1.29 Impact Factor
  • Nosotchu 01/2013; 35(2):143-146. DOI:10.3995/jstroke.35.143
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: Glioblastoma (GBM) is one of the worst cancers in terms of prognosis. Standard therapy consists of resection with concomitant chemoradiotherapy. Resistance to nimustine hydrochloride (ACNU), an alkylating agent, has been linked to methylguanine DNA methyltransferase (MGMT). Daily administration of procarbazine (PCZ) has been reported to decrease MGMT activity. This study investigated the efficacy of ACNU + PCZ compared to ACNU alone for GBM and anaplastic astrocytoma (AA). METHODS: Patients (20-69 years) who had newly diagnosed AA and GBM were randomly assigned to receive radiotherapy with ACNU alone or with ACNU + PCZ. The primary endpoint was overall survival (OS). This was designed as a phase II/III trial with a total sample size of 310 patients and was registered as UMIN-CTR C000000108. RESULTS: After 111 patients from 19 centers in Japan were enrolled, this study was terminated early because temozolomide was newly approved in Japan. The median OS and median progression-free survival (PFS) with ACNU alone (n = 55) or ACNU + PCZ (n = 56) in the intention-to-treat population were 27.4 and 22.4 months (p = 0.75), and 8.6 and 6.9 months, respectively. The median OS and median PFS of the GBM subgroup treated with ACNU alone (n = 40) or ACNU + PCZ (n = 41) were 19.0 and 19.5 months, and 6.2 and 6.3 months, respectively. Grade 3/4 hematologic adverse events occurred in more than 40 % of patients in both arms, and 27 % of patients discontinued treatment because of adverse events. CONCLUSIONS: The addition of PCZ to ACNU was not beneficial, in comparison with ACNU alone, for patients with newly diagnosed AA and GBM.
    Cancer Chemotherapy and Pharmacology 12/2012; 71(2). DOI:10.1007/s00280-012-2041-5 · 2.57 Impact Factor

Publication Stats

5k Citations
554.05 Total Impact Points

Institutions

  • 1990–2015
    • Kyoto University
      • • Center for iPS Cell Research and Application (CiRA)
      • • Division of Pharmaceutical Sciences
      • • Institute for Frontier Medical Sciences
      • • Department of Neurosurgery
      Kioto, Kyōto, Japan
  • 1990–2014
    • Tazuke Kofukai Medical Research Institute, Kitano Hospital
      Ōsaka, Ōsaka, Japan
  • 2010
    • National Hospital Organization Minami Kyoto Hospital
      Kioto, Kyōto, Japan
  • 2006
    • Hamamatsu Rosai Hospital
      Hamamatu, Shizuoka, Japan
    • Kanazawa University
      • Department of Neurosurgery
      Kanazawa, Ishikawa, Japan
  • 2004
    • National Cerebral and Cardiovascular Center
      Ōsaka, Ōsaka, Japan
  • 2000
    • Osaka City University
      • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan