2007 Fiscal Year Final Research Report Summary
An analysis of molecular mechanism underlying spastin-induced spastic paraplegia and a strategy for the development of targeted therapies for the disease
| Project/Area Number |
18590954
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurology
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| Research Institution | Jichi Medical University |
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Principal Investigator |
TAKIYAMA Yoshihisa Jichi Medical University, School of Medicine, Lecturer (00245052)
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| Co-Investigator(Kenkyū-buntansha) |
SAKOE Kumi University of Yamanashi, Dept. Haematology, Assistant Professor (10398505)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Hereditary Spastic Paraplegia / Spastin / anti-spastin antibody / siRNA / Vinblastine / SPG4 / SPG7 |
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| Research Abstract |
The most common form of autosomal dominant hereditary spastic paraplegias (HSPs) is caused by mutations in the SPG4/SPAST gene, encoding spastin, a member of the AAA family of ATPases. Although spastin are suggested to be involved in microtubule dynamics, we have no due of the mechanism by which spastin mutations may lead to degeneration of corticospinal axons. Therefore, we investigated the function of spastin and the molecular mechanism underlying neurodegeneration due to spastin mutations. In addition, we attempted to find treatment agents for SPG4.
(1) Subcellular localization of endogenous spastin :
We investigated the subcellular localization of endogenous spastin in HeLa and NT2 cells using a spastin-specific antibody. In Hela cells, Spastin is predominantly localized in the nucleus during the interphase, with enrichment toward the centrosome and the spindle in the metaphase. In the telophase, spastin is concentrated in the nucleus and midzone region, with intense staining in the
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midbody. The results indicate that spastin plays an important role in cell division with microtubule severing process. In NT2 cells, spastin is enriched in the growth cone and in the branching regions. siRNA knock-down of spastin expression showed abnormal elongation and swelling of neurite, suggesting that spawn is essential far axon outgrouth.
(2) Screening of possible treatment agents for SPG4
We established a screening system (siRNA knock-down of spastin expression in NT2 and SHSY5Y cells) of possible treatment agents for SPG4. Then screening of possible treatment agents for SPG4 was performed using the system. Although vinblastin rescued the abnormal expansion of neurite, it also induced neuronal cell death.
(3) Gene expression profiling on sacsin
We performed gene-profiling experiments to identify genes that are expressed at low levels together with siRNA knock-down of spastin expression. We found some candidate genes that could be associated with spastin. Among them, a gene was associated with the elongation of neurite and stability of microtubules, and was co-localized with spastin at the top of the neurite. To elucidate the net-work system associated with spastin will shed light on the establishment of treatment for SPG4. Less
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