| Project/Area Number |
23K14367
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 47040:Pharmacology-related
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| Research Institution | National Center of Neurology and Psychiatry |
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Principal Investigator |
全 麗麗 国立研究開発法人国立精神・神経医療研究センター, 神経研究所 神経薬理研究部, リサーチフェロー (80906975)
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| Project Period (FY) |
2023-04-01 – 2026-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2025: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2024: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2023: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | spinal cord injury / Hnrnpu / astrocyte / glial scar formation / proliferation / central nervous system |
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| Outline of Research at the Start |
Following spinal cord injury (SCI), astrocytes are the predominant cellular component that proliferate and migrate to the lesion core for the contribution of glial scar formation, which has long been considered a major cause of neuronal regeneration failure. However, the detailed molecular mechanisms by which astrocytes in response to central nervous system (CNS) injury remain unclear. Our objective is to explore interventions on potential regulators that govern scar formation by astrocytes to facilitate the regeneration of neural circuits following injury.
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| Outline of Annual Research Achievements |
Through functional screening of highly expressed genes in the pathological state of spinal cord astrocytes, we identified heterogeneous nuclear ribonucleoprotein U (Hnrnpu) as a potential endogenous molecule that regulates astrocyte proliferation. In this fiscal year, we focused on the role of Hnrnpu in regulating the proliferation and migration of astrocytes, processes that are essential in the pathology of spinal cord injury, through in vitro experiments. Our findings demonstrate that inhibiting Hnrnpu suppresses BrdU incorporation and wound closure in primary astrocytes, indicating its crucial involvement in these processes. Additionally, Hnrnpu inhibition alters gene expression characteristic of reactive and scar-forming astrocytes, suggesting its potential role in phenotypic and transcriptomic changes associated with astrocytic scar formation post-CNS injury. Consistent results were observed in both mouse and human astrocytes, highlighting the broad relevance of Hnrnpu. RNA-seq analysis revealed hundreds of differentially expressed genes. Furthermore, gene ontology enrichment analysis indicated that Hnrnpu-deficient human astrocytes change the expression of gene sets annotated with cell population proliferation, cell migration, wound healing, and axon guidance, further implicating Hnrnpu in astrogliosis and glial scar formation.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Building upon successful in vitro studies confirming the impact of Hnrnpu on astrocytic phenotypic and transcriptomic changes associated with glial scar formation, we proceeded to in vivo investigations. Utilizing a dorsal hemisection injury model of the spinal cord, we observed an upregulation of Hnrnpu expression post-injury, mirroring the trend of astrocyte proliferation. This supports the notion that Hnrnpu may indeed play a role in astrocyte proliferation following spinal cord injury. To delve deeper into the function of Hnrnpu in astrocytes, we plan to manipulate its expression through AAV virus injection.
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| Strategy for Future Research Activity |
Based on the aforementioned observations, we have established that Hnrnpu plays a crucial role in astrocyte proliferation both in vitro and in vivo spinal cord injury models. To manipulate Hnrnpu expression specifically in astrocytes in vivo, we will develop an astrocyte-targeted adeno-associated virus (AAV) 2/5-mir30-based shRNA knockdown vector. This vector will express enhanced green fluorescent protein under the control of the glial fibrillary acidic protein (GFAP) promoter. Subsequently, we will assess whether Hnrnpu knockdown in astrocytes influences glial scar formation, motor function recovery, and axonal regeneration in injured mice.
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