Introduction Our group has conducted extensive basic and preclinical studies of the use of human induced pluripotent cell (iPSC)-derived neural stem/progenitor cell (hiPSC-NS/PC) grafts in models of spinal cord injury (SCI). Evidence from animal experiments suggests this approach is safe and effective. We are preparing to initiate a first-in-human clinical study of hiPSC-NS/PC transplantation in subacute SCI. Setting NS/PCs were prepared at a Good Manufacturing Practice-grade cell processing facility at Osaka National Hospital using a clinical-grade integration-free hiPSC line established by the iPSC Stock Project organized by the Kyoto University Center for iPS Cell Research and Application. After performing all quality checks, the long-term safety and efficacy of cells were confirmed using immunodeficient mouse models. Methods The forthcoming clinical study uses an open-label, single-arm design. The initial follow-up period is 1 year. The primary objective is to assess the safety of hiPSC-NS/PC transplantation in patients with subacute SCI. The secondary objective is to obtain preliminary evidence of its impact on neurological function and quality-of-life outcomes. Four patients with C3/4-Th10 level, complete subacute (within 24 days post-injury) SCI will be recruited. After obtaining consent, cryopreserved cells will be thawed and prepared following a multi-step process including treatment with a γ-secretase inhibitor to promote cell differentiation. A total of 2 × 10 6 cells will be transplanted into the injured spinal cord parenchyma 14–28 days post-injury. Patients will also receive transient immunosuppression. This study protocol has been reviewed and approved by the Certified Committee for Regenerative Medicine and the Japanese Ministry of Health, Labor and Welfare (University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number, UMIN000035074; Japan Registry of Clinical Trials [jRCT] number, jRCTa031190228). Discussion/conclusion We plan to start recruiting a patient as soon as the COVID-19 epidemic subsides. The primary focus of this clinical study is safety, and the number of transplanted cells may be too low to confirm efficacy. After confirming safety, a dose-escalation study is planned.

The transplantation of neural progenitor cells (NPCs) derived from human induced pluripotent stem cells (iPSCs) has beneficial effects on spinal cord injury (SCI). However, while there are many subtypes of NPCs with different regional identities, the subtype of iPSC-derived NPCs that is most appropriate for cell therapy for SCI has not been identified. Here, we generated forebrain- and spinal cord-type NPCs from human iPSCs and grafted them onto the injured spinal cord in mice. These two types of NPCs retained their regional identities after transplantation and exhibited different graft-host interconnection properties. NPCs with spinal cord regional identity but not those with forebrain identity resulted in functional improvement in SCI mice, especially in those with mild-to-moderate lesions. This study highlights the importance of the regional identity of human iPSC-derived NPCs used in cell therapy for SCI.

Recent advances in systemic treatments for mucopolysaccharidosis have led to therapies that improve the multiple somatic features of this disease, but the therapeutic effect on ocular manifestations such as corneal clouding is not satisfactory. Here, we administered an adenovirus expressing human beta-glucuronidase (AxCAhGUS) into the anterior chamber or intrastromal region of the cornea in mice with mucopolysaccharidosis type VII (B6/MPSVII), and successfully treated corneal clouding of MPSVII. When we injected AxCAhGUS into the anterior chamber of the eyes, cells expressing beta-glucuronidase (GUSB) were located mainly in the trabecular meshwork as well as in all corneal regions, and subsequent pathological corrections in the cornea were achieved. Widespread transgene expression was also observed when we administered AxCAhGUS inside the cornea after lamellar keratotomy, and rapid elimination of the lysosomal storage in the corneal keratocytes occurred. Furthermore, intrastromal vector administration did not generate significant levels of anti-adenovirus neutralizing antibodies, and secondary vector administration was effective. Based on these observations, we conclude that it is worth developing a treatment strategy for corneal clouding in mucopolysaccharidosis based on direct intraocular administration of adenoviral vectors.

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Eleven 3-substituted isocoumarins and a benzylidenephthalide were synthesized through thermal cyclization reaction of delta- and gamma-ketoamides, respectively. Subsequent deprotection of the hydroxyl groups of the resulting isocoumarin and benzylidenephthalide compounds afforded thunberginols A, B, and F, respectively, which originated from the processed leaves of Hydrangea macrophylla SERINGE var. thunbergii MAKINO. The synthesized isocoumarins and thunberginols were evaluated for their anti-allergic activity, in which thunberginol B exhibited the highest inhibitory potency on the degranulation of RBL-2H3 cells induced by antigen. Structure-activity relationship studies were carried out to determine the necessary substituents on the 3-phenylisocoumarin skeleton for inhibitory activity.

Cell-mediated gene therapy for visceral lesions of lysosomal storage diseases is promising; however, the treatment of central nervous system (CNS) lesions remains a challenge. In this study, we generated rat amniotic epithelial cells (AEC) that overexpress and secrete human beta-glucuronidase (GUSB) following transduction with an adenoviral vector encoding human GUSB. The AEC were used as donor cells for cell-mediated gene therapy of CNS lesions in mice with mucopolysaccharidosis type VII (MPSVII), a lysosomal storage disorder caused by an inherited deficiency of GUSB activity. After confirmation that the secreted GUSB was taken up mainly via mannose 6-phosphate receptors in primary cultured neurons, the AEC were transplanted into the brains of adult MPSVII mice. Histochemical analysis showed extensive GUSB activity throughout the ipsilateral hemisphere of the recipient brains, and pathological improvement of the lysosomal storage was observed even in regions far from the site of injection. These results suggest that intracerebral transplantation of genetically engineered AEC has therapeutic potential for the treatment of CNS lesions in lysosomal storage disorders.

Systemic injection of an adenovirus vector into adult mice resulted in pathological improvements in multiple visceral organs of mice with mucopolysaccharidosis VII; however, no therapeutic efficacy was observed for mental retardation, skeletal deformities, corneal clouding, and retinal degeneration. In this study, an adenovirus vector expressing human bglucuronidase was injected into mice with mucopolysaccharidosis VII within 24 h of birth, and therapeutic efficacy was evaluated. In the brains of the mice, more than 20% of GUSB activity was maintained for at least 20 weeks after birth, and histopathological analysis showed no obvious lysosomal storage. Furthermore, no vacuolated cells were detected in corneal stroma and retinal pigment epithelium in the eyes of the mice treated in the neonatal period, while pathological improvement was not observed in adult MPSVII mice that received similar treatments. The treated mice also lacked characteristic facial skeletal deformities, and radiographic analysis demonstrated that their facial and cranial bones were morphologically normal. These results indicate that a single systemic adenovirus injection in the neonatal period could prevent the progression of mental retardation, corneal clouding, retinal degeneration, and skeletal deformities, all of which are frequently observed clinical manifestations and difficult to treat in adulthood.

Transplantation of neural stem/progenitor cells (NS/PCs) derived from human induced pluripotent stem cells (hiPSCs) is considered to be a promising therapy for spinal cord injury (SCI) and will soon be translated to the clinical phase. However, how grafted neuronal activity influences functional recovery has not been fully elucidated. Here, we show the locomotor functional changes caused by inhibiting the neuronal activity of grafted cells using a designer receptor exclusively activated by designer drugs (DREADD). In vitro analyses of inhibitory DREADD (hM4Di)-expressing cells demonstrated the precise inhibition of neuronal activity via administration of clozapine N-oxide. This inhibition led to a significant decrease in locomotor function in SCI mice with cell transplantation, which was exclusively observed following the maturation of grafted neurons. Furthermore, trans-synaptic tracing revealed the integration of graft neurons into the host motor circuitry. These results highlight the significance of engrafting functionally competent neurons by hiPSC-NS/PC transplantation for sufficient recovery from SCI.