Gene transfer of dopamine-synthesizing enzymes into the striatal neurons has led to behavioral recovery in animal models of Parkinson's disease (PD). We evaluated the safety, tolerability, and ...potential efficacy of adeno-associated virus (AAV) vector–mediated gene delivery of aromatic L-amino acid decarboxylase (AADC) into the putamen of PD patients. Six PD patients were evaluated at baseline and at 6 months, using multiple measures, including the Unified Parkinson's Disease Rating Scale (UPDRS), motor state diaries, and positron emission tomography (PET) with 6-18Ffluoro-L-m-tyrosine (FMT), a tracer for AADC. The short-duration response to levodopa was measured in three patients. The procedure was well tolerated. Six months after surgery, motor functions in the OFF-medication state improved an average of 46% based on the UPDRS scores, without apparent changes in the short-duration response to levodopa. PET revealed a 56% increase in FMT activity, which persisted up to 96 weeks. Our findings provide class IV evidence regarding the safety and efficacy of AADC gene therapy and warrant further evaluation in a randomized, controlled, phase 2 setting.
In Japan, the Pharmaceuticals and Medical Devices Law was passed in 2014. In this new law, regenerative medical products were defined, and a conditional and term-limited approval system only for ...regenerative medical products was instituted. Therefore, regenerative medical products can be approved based on phase I and/or II trials. Gene therapy and adoptive cellular therapy are categorized as regenerative medical products. This law is intended for registration trials for marketing authorization. The Act on the Safety of Regenerative Medicine was also implemented in 2014. This act is intended for clinical research and medical practice involving processed cells other than registration trials. Under this act, a review of plans on medical treatments or clinical studies by a certified committee and submission of the plans to the Ministry of Health, Labour and Welfare (MHLW) are mandatory. The MHLW instituted the SAKIGAKE (meaning a pioneer or forerunner in Japanese) designation system in 2015. This designation is similar to the breakthrough therapy designation in the US and PRIME in the EU. In addition, the MHLW started the "Project for Enhanced Practical Application of Innovative Drugs, Medical Devices and Regenerative Medical Products" to promote personnel exchange and cooperation in writing of guidelines on the evaluation of innovative medical products between the Pharmaceuticals and Medical Devices Agency and academia. Some new guidelines regarding gene and cellular therapy were published.
In this review, we comprehensively described these complicated regulations and problems to be solved in order to facilitate global readers' understanding of Japanese regulatory frameworks.
Two-photon imaging with genetically encoded calcium indicators (GECIs) enables long-term observation of neuronal activity in vivo. However, there are very few studies of GECIs in primates. Here, we ...report a method for long-term imaging of a GECI, GCaMP6f, expressed from adeno-associated virus vectors in cortical neurons of the adult common marmoset (Callithrix jacchus), a small New World primate. We used a tetracycline-inducible expression system to robustly amplify neuronal GCaMP6f expression and up- and downregulate it for more than 100 days. We succeeded in monitoring spontaneous activity not only from hundreds of neurons three-dimensionally distributed in layers 2 and 3 but also from single dendrites and axons in layer 1. Furthermore, we detected selective activities from somata, dendrites, and axons in the somatosensory cortex responding to specific tactile stimuli. Our results provide a way to investigate the organization and plasticity of cortical microcircuits at subcellular resolution in non-human primates.
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•An AAV vector system for enhanced and controllable expression of GCaMP6f is developed•This system allows long-term two-photon neuronal imaging in the marmoset brain•The same neuronal populations can be followed over 100 days•Neuronal responses to tactile stimulation can be imaged at subcellular resolution
Long-term two-photon calcium imaging has been challenging in non-human primates. Sadakane et al. use an inducible expression system to visualize cortical neurons in adult marmosets. They show that the same neuronal population can be followed over 100 days and neuronal responses to tactile stimulation can be imaged at subcellular resolution.
The paraventricular thalamic nucleus (PVT) is a part of epithalamus and sends outputs to emotion-related brain areas such as the medial prefrontal cortex, nucleus accumbens, and amygdala. Various ...functional roles of the PVT in emotion-related behaviors are drawing attention. Here, we investigated the effect of manipulation of PVT neurons on the firing patterns of medial prefrontal cortical (mPFC) neurons and depression-like behavior. Extracellular single-unit recordings revealed that acute activation of PVT neurons by hM3Dq, an activation type of designer receptors exclusively activated by designer drugs (DREADDs), and administration of clozapine N-oxide (CNO) caused firing rate changes in mPFC neurons. Moreover, chronic presynaptic inhibition in PVT neurons by tetanus toxin (TeTX) increased the proportion of interneurons among firing neurons in mPFC and shortened the immobility time in the forced swimming test, whereas long-term activation of PVT neurons by hM3Dq caused recurrent hypoactivity episodes. These findings suggest that PVT neurons regulate the excitation/inhibition balance in the mPFC and mood stability.
The corticospinal (CS) tract is essential for voluntary movement, but what we know about the organization and development of the CS tract remains limited. To determine the total cortical area ...innervating the seventh cervical spinal cord segment (C7), which controls forelimb movement, we injected a retrograde tracer (fluorescent microspheres) into C7 such that it would spread widely within the unilateral gray matter (to >80%), but not to the CS tract. Subsequent detection of the tracer showed that, in both juvenile and adult mice, neurons distributed over an unexpectedly broad portion of the rostral two-thirds of the cerebral cortex converge to C7. This even included cortical areas controlling the hindlimbs (the fourth lumbar segment, L4). With aging, cell densities greatly declined, mainly due to axon branch elimination. Whole-cell recordings from spinal cord cells upon selective optogenetic stimulation of CS axons, and labeling of axons (DsRed) and presynaptic structures (synaptophysin) through cotransfection using exo utero electroporation, showed that overgrowing CS axons make synaptic connections with spinal cells in juveniles. This suggests that neuronal circuits involved in the CS tract to C7 are largely reorganized during development. By contrast, the cortical areas innervating L4 are limited to the conventional hindlimb area, and the cell distribution and density do not change during development. These findings call for an update of the traditional notion of somatotopic CS projection and imply that there are substantial developmental differences in the cortical control of forelimb and hindlimb movements, at least in rodents.
Objectives
Increasing numbers of reports have described hematopoietic improvement after iron chelation therapy in iron‐overloaded patients. These observations indicate that excess iron could affect ...hematopoiesis unfavorably. To investigate how excess iron affects hematopoiesis in vivo, we generated iron‐overloaded mice and examined hematopoietic parameters in these mice.
Methods
We generated iron‐overloaded mice by injecting 200 mg of iron dextran into C57BL/6J mice, and immature hematopoietic cells in the bone marrow were evaluated by flow cytometric analyses, colony‐forming assays, and bone marrow transplantation analyses. We also examined changes in molecular profiles of the hematopoietic microenvironment.
Results and Conclusions
Iron‐overloaded (IO) mice did not show significant defects in the hematopoietic data of the peripheral blood. Myeloid progenitor cells in the bone marrow were increased in IO mice, but the number and function of the erythroid progenitors and hematopoietic stem cells were not significantly affected. However, bone marrow transplantation from normal donors to IO recipients showed delayed hematopoietic reconstitution, which indicates that excess iron impacts the hematopoietic microenvironment negatively. Microarray and quantitative RT‐PCR analyses on the bone marrow stromal cells demonstrated remarkably reduced expression of CXCL12, VCAM‐1, Kit‐ligand, and IGF‐1 in the iron‐overloaded mice. In addition, erythropoietin and thrombopoietin levels were significantly suppressed, and increased oxidative stress was observed in the IO bone marrow and liver. Consequently, our findings indicate that excess iron can damage bone marrow stromal cells and other vital organs, disrupting hematopoiesis presumably by increased oxidative stress.
Summary
To reduce the delay in marketing authorization of drugs in Japan, four Japanese national projects were instituted. We examined all oncologic drugs for adult patients approved or discussed ...through these schemes, for the first time. All the data are publicly available. In total, 197 applications/demands (181 indications and 16 dosages/uses) were collected. As of December 31, 2015, 64 indications and 10 dosages/uses were approved as off-label drugs through these schemes without conducting additional registration trials in Japan. Furthermore, 46 indications and two dosages/uses were approved after registration trials in Japan requested by the national scheme councils. Regarding the following 23 indications of the 197 applications/demands, registration trials in Japan were commenced after the national scheme council’s request: 17 hematological malignancies and six orphan solid tumors. Moreover, 54 indications and three dosages/uses, for which demands were submitted, were regarded as not a high medical priority by the national scheme council. Regarding two hematological malignancy indications, the dosage approved in foreign countries was intolerable for the Japanese patients in Japanese registration trials and this stopped the clinical development in Japan. Our analysis showed that 110 indications and 12 dosages/uses were approved in Japan through these schemes. These national projects have provided numerous therapeutic options for Japanese patients and may be meaningful for promoting clinical development and regulatory approval especially in orphan diseases in countries other than Japan.
Restoring dopamine production in the putamen through gene therapy is a straightforward strategy for ameliorating motor symptoms for Parkinson's disease (PD). In a ...1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity-based primate model of PD, we previously showed the safety and efficacy of adeno-associated viral (AAV) vector-mediated gene delivery to the putamen of three dopamine-synthesizing enzymes (tyrosine hydroxylase TH, aromatic l-amino acid decarboxylase AADC, and guanosine triphosphate cyclohydrolase I GCH) up to 10 months postprocedure. Although three of four monkeys in this study have previously undergone postmortem analysis, one monkey was kept alive for 15 years after gene therapy to evaluate long-term effects. Here, we report that this monkey showed behavioral recovery in the right-side limb that remained unchanged for 15 years, at which time euthanasia was carried out owing to onset of senility. Immunohistochemistry of the postmortem brain from this monkey revealed persistent expression of TH, AADC, and GCH genes in the lesioned putamen. Transduced neurons were broadly distributed, with the estimated transduction region occupying 91% of the left postcommissural putamen. No signs of cytotoxicity or Lewy body pathology were observed in the AAV vector-injected putamen. This study provides evidence of long-term safety and efficacy of the triple-transduction method as a gene therapy for PD.
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