The delay and loss of drugs are serious problems in Japan. To overcome this issue, it is important to strengthen drug development capabilities. For drug development, the establishment and advancement of non-clinical testing methods are necessary for safe and effective clinical trials. Recently, the movement toward alternatives to animal testing has accelerated internationally. New Approach Methodologies (NAMs), such as human inducible pluripotent stem cell (hiPSC) technology and in silico modeling & simulation, are considered valuable for drug development. It has been demonstrated that hiPSC-derived cardiomyocytes (hiPSC-CMs) are useful tools to assess drug-induced cardiotoxicity, including arrhythmia and cardiac contractile dysfunction, leading to the use of hiPSC-CMs in the drug review process. Advancing hiPSC technologies have enabled the generation of mature hiPSC-CMs and engineered heart tissues, which are expected to provide novel information in drug safety and efficacy evaluation. Furthermore, it would be possible to establish the non-clinical evaluation that takes into account individual differences by developing hiPSCs bearing characteristics specific to certain populations, such as pediatrics or rare disease patients. Here, we present the recent findings and future perspectives on non-clinical evaluation using hiPSC technology.

Currently, a variety of anticancer agents are used in the treatment of cancer. Since anticancer agents are used continuously over a long time, they carry the risk of side effects. One of the major side effects is cardiac dysfunction. For example, doxorubicin, an anthracycline-type anticancer agent, is clinically restricted because of its dose-dependent cardiotoxicity. Cardiotoxicity includes decreased ejection fraction, arrhythmias, and congestive heart failure, all of which are associated with high mortality rates. Therefore, it is important to assess the risk of cardiotoxicity of anticancer agents in advance. Cardiomyocytes require energy to beat and retain an abundance of mitochondria. We established quantitative measurements of mitochondrial length and respiratory activities using cardiomyocytes. We found that exposure of human iPS cell-derived cardiomyocytes (hiPSC-CMs) to anticancer agents with reported cardiotoxicity enhanced mitochondrial hyperfission and the oxygen consumption rate was significantly reduced. Knockdown of dynamin-related protein 1 (Drp1), mitochondrial fission-accelerating GTP-binding protein, suppressed mitochondrial hyperfission in hiPSC-CMs. This indicates that visualizing mitochondrial functions in hiPSC-CMs will be helpful in assessing the risk of cardiotoxicity caused by anticancer agents and that maintaining mitochondrial quality will become a new strategy to reduce anticancer agents-induced cardiotoxicity. In this review, we present the evaluation of cardiotoxicity targeting mitochondrial quality in anticancer agents, using osimertinib, a non-small cell lung cancer drug, as an example.

Human induced pluripotent stem cells derived cardiomyocytes (hiPSC-CMs) can recapitulate the properties of human cardiomyocyte and exhibit disease phenotypes in vitro, attributable to their healthy- or patient-specific genetic backgrounds. Therefore, hiPSC-CMs are a crucial tool for developing therapeutic agents for cardiovascular diseases, and regenerative medicine using hiPSC-CMs is expected to be an alternative therapy to heart transplantation. Moreover, the development of organoid models has been advanced to replicate the complex structure of heart tissue in vitro, thereby effectively facilitating drug discovery. On the other hand, current methods for advancing drug discovery using hiPSC-CMs face limitations, including the difficulty of quantifying characteristics such as cell structure and predicting the risk and efficacy of candidate drug in clinical practice. In the field of regenerative medicine, challenges include quality control and the verification of safety of transplanted cells in human. In silico model, including artificial intelligence (AI) and simulation, have been developed in the field of drug discovery using hiPSC-CMs. These advancements encompass phenotype scoring via AI and risk prediction through simulations. This review outlines the current status and challenges of drug discovery using hiPSC-CMs and in silico model, based on the published reports.

Glaucoma is an age-related neurodegenerative disease and the leading cause of blindness, but currently no fundamental treatment has been present. The main treatment is to reduce intraocular pressure, which is expected to delay the progression of the disease. However, there are many glaucoma patients for whom progression cannot be controlled by lowering intraocular pressure alone, and the development of a fundamental treatment is required. Meanwhile, the clinical application of gene therapy is increasing worldwide. Various gene therapy vectors are still being developed, and technological change is much faster in this field. Gene therapy has already been clinically applied to several neurodegenerative diseases, but gene therapy for glaucoma has not yet been established. Our group is investigating the development of a new treatment for glaucoma by gene therapy using neurotrophic factor signaling. And we aim not only to suppress disease progression by neuroprotection, but also to recover the visual function by axonal regeneration.

Age-related macular degeneration (AMD) is one of the most common neuroinflammatory diseases that is the leading cause of blindness worldwide. AMD is caused by not only mutations in immune-related genes such as Cfh (complement factor H) but also the accumulation of environmental factors such as obesity and other inflammatory triggers with age. Our study found that the past histories of obesity can lead to immunological reprogramming in the innate immune system and affect the development of AMD in later life. This reveals a new link in the role of innate immune memory in neuroinflammatory diseases such as AMD, and intervention in innate immune memory may be a new therapeutic strategy.

The ocular tissue is one of the most densely populated tissues in the body with extremely small blood vessels, and vascular lesions have been reported to be a factor in vision loss and visual field defects in many ocular diseases. Currently, vascular endothelial growth factor (VEGF)-targeted agents are the first line of treatment for intraocular vascular lesions, however, there are some cases in which they are not fully effective. Therefore, we explored pathogenic molecules other than VEGF, aiming to develop new molecular-targeted therapy. Using an experimental pathological model mimicking intraocular vascular lesions, we found that B-cell CLL/lymphoma 6 member B protein (BCL6B), which has been identified as a Bric-a-brac, Tramtrack, and Broad Complex protein, may play an important role in intraocular angiogenesis and vascular hyperpermeability. In this article, we introduce the usefulness of suppressing BCL6B expression and discuss the possibility of drug discovery by targeting Notch signaling in chorioretinal vascular lesions.

In the overall Japanese population, the prevalence of perennial allergic rhinitis (AR) increased from 18.7% to 24.5% from 1998 to 2019. For Japanese cedar pollen (JCP) induced AR, the prevalence in the same period increased from 16.2% to 38.8% in the general population and from 7.2% to 30.1% in children (5–9 years), indicating a serious problem especially in younger age groups. Allergy immunotherapy (AIT) is an AR treatment modality that induces immune tolerance to allergens by repeated allergen administration and is the only treatment form that reduces symptoms and medication use and provides sustained effect after treatment completion. In Japan, AIT is available primarily as sublingual immunotherapy (SLIT) tablets. Two tablets based on a freeze-dried formulation (a JCP SLIT-tablet, approved 2018, and a house dust mite (HDM) SLIT-tablet, approved 2015), and one tablet based on a compressed formulation (HDM, approved 2015) are available. For SLIT to be effective, the concentration of allergen when solubilized in saliva must be as high as possible for as long as possible within the recommended sublingual holding time (1–2 minutes), parameters that must be supported by the tablet formulation. The characteristics of the freeze-dried and compressed formulations were compared using the HDM SLIT-tablets. Freeze-dried tablets disintegrated immediately and displayed fast and complete HDM allergen release in solvent, while compressed tablets disintegrated more slowly and provided only incomplete allergen release. Freeze-dried SLIT-tablets are believed to provide full mucosal availability of the allergen content during the sublingual holding time, and a low medication burden.

The prevalence of allergic rhinitis (AR) reached 49.2% in 2019. In particular, the prevalence of Japanese cedar (JC) pollinosis is 38.8%, and the onset age of pollinosis is becoming younger. AR is known to be a risk factor for the development of allergic asthma, a potentially life-threatening condition. Allergen immunotherapy (AIT) is a well-documented, safe, effective treatment option for respiratory allergic disease. It has been demonstrated that AIT can provide relief from clinical symptoms and that AIT has the potential to provide long-term post-treatment effect. Unlike pharmacotherapy, AIT addresses the basic immunological mechanisms that are responsible for the development and persistence of allergic conditions. Currently, two main routes of AIT administration, subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), are commonly available. In Japan, house dust mite (HDM) SLIT tablets have been available since 2015, and JC SLIT tablet had been approved by 2018 without any age limitation. The randomized double-blind, placebo-controlled trials that included pediatric patients have been conducted in Japan. In phase II/III trail with JC SLIT tablets, treatment effect-size (improvement of clinical symptoms compared to placebo) was 46.3% after three years treatment. In addition, AR was improved in 40% (1 year) and 30% (2 years) after discontinuation of SLIT. Several future initiatives including the AIT against cedar pollen allergies were announced by Japanese government. This review covered the findings to date, including immunotherapy not only for JC pollinosis- but also for HDM-induced perennial AR.

Allergen-specific immunotherapy (AIT) has been a longstanding treatment for allergic diseases. Historically, subcutaneous immunotherapy was the main approach, but with the development of sublingual preparations, which are associated with fewer systemic side effects, sublingual immunotherapy is gaining global popularity. In Japan, the approval of standardized sublingual immunotherapy preparations in 2014 has significantly accelerated its adoption. The mechanism of allergic inflammation is divided into sensitization and elicitation phases. The sensitization phase involves the production of antigen-specific IgE antibodies against a particular antigen. These IgE antibodies bind to FcεRI on mast cells and basophils, preparing the body for an allergic response. The elicitation phase occurs when the body, already primed with these antibodies, is re-exposed to the same antigen, triggering inflammation and symptoms. This phase includes mechanisms where IgE-mediated mast cell activation leads to degranulation and where local Th2 cell activation induces inflammation. While the mechanisms of AIT are not fully understood, they are categorized into desensitization and immune tolerance. Desensitization is induced by reducing the responsiveness of mast cells and basophils to the antigen. Immune tolerance involves the production of antigen-specific IgG4 antibodies that compete with IgE for antigen binding, and the induction of regulatory T cells and other anti-inflammatory immune cells producing cytokines such as IL-10. AIT still faces challenges, such as the lack of predictive biomarkers for efficacy. Recent studies indicate that HLA genotypes influence AIT responsiveness. Advances in genetic and single-cell analysis are expected to address these challenges, paving the way for improved treatment outcomes.

Distal myopathy with rimmed vacuoles (GNE myopathy) is an incurable disease that develops after the late teens, progresses slowly, and has no effective treatment. It is inherited in an autosomal recessive manner, and the number of patients in Japan is estimated to be around 400. The causative gene was revealed to be GNE, the rate-limiting enzyme in the sialic acid biosynthesis pathway, and non-clinical studies demonstrated the effectiveness of sialic acid. Tohoku University Hospital conducted an investigator-initiated phase I trial with aceneuraminic acid in 2010. After that, trials were conducted overseas, and a phase II trial using acenoiraminic acid sustained-release tablets confirmed that muscle strength in the upper limbs had recovered, and the drug progressed to a phase III trial. In Japan, a Phase II/III study was conducted at five domestic facilities using the same protocol as the overseas Phase III study, and efficacy and safety were confirmed. However, Phase III trials overseas failed to show efficacy and development was discontinued. An additional confirmation study was conducted in Japan, and as a result of confirming reproducibility, the product was approved for manufacturing and sales in March 2024, ahead of the rest of the world. This is a successful example of the development of a therapeutic drug for an ultra-orphan disease, which is said to be difficult to develop, and is expected to lead to early treatment for patients.

Elucidating the neural mechanisms governing changes in individual animal behavior is a key goal in neuroscience. Such research has important implications for behavioral pharmacology and could lead to the development of treatments for psychiatric and neurological disorders. Given that the brain likely represents vast amounts of information through the combined activity of multiple neurons, studying these mechanisms requires the simultaneous recording of many neurons. Recent years have seen significant advancements in techniques for multi-cellular activity recording. Calcium imaging utilizing fluorescent sensors has emerged as a powerful method, enabling the concurrent acquisition of spatial arrangements and temporal activity changes in neuronal populations. This article focuses on deep brain imaging using GRIN lenses, particularly deep brain calcium imaging in freely behaving animals with miniaturized head-mounted microscopes. We compare the strengths and limitations of this approach to other calcium imaging methods, electrophysiological techniques, and fiber photometry. Finally, we discuss future developments in this field, including two-photon microscopy for imaging beyond cell bodies, membrane potential imaging using voltage sensors, and single-cell resolution manipulation of neural activity by integrating spatial light modulators and electrically tunable lenses.