2012 Fiscal Year Final Research Report
Investigation of the molecular mechanism of the radical reaction to induce the amyloid fibril derived from the transthyretin
| Project/Area Number |
22590540
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Laboratory medicine
|
|---|
| Research Institution | Osaka Medical College |
|---|
Principal Investigator |
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKUBO Takayuki 大阪医科大学, 医学部, 教授 (60163359)
TSUJI Motomu 大阪医科大学, 医学部, 教授 (60144466)
YAMAMOTO Daisuke 大阪医科大学, 医学部, 准教授 (50240106)
NAITO Yasuhide 光産業創成大学院大学, 光医療健康分野, 准教授 (40237186)
|
|---|
| Project Period (FY) |
2010 – 2012
|
| Keywords | アミロイド / ラジカル反応 / 質量イメージング / 凝集体形成 |
|---|
| Research Abstract |
Senile systemic amyloidosis and familial amyloid polyneuropathy are caused by oxidative deposition of conformationally altered transthyretin (TTR). We identified oxidative modification of the 10th cysteine of TTR through S-sulfonation in vitro. Based on mass spectrometric analysis, we determined the spectrophotometric, western blotting, and fluorescent microscopic properties of TTR incubated with and without cysteine-S-sulfonate in acidic (pH 4) and alkaline (pH 8) conditions at 37 degrees. The absorption of the aggregated TTR molecules increased more with incubation time and the concentration of cysteine-S-sulfonate at pH 4 than at pH 8. The Congo red binding to the S-sulfonated TTR at pH 4 was saturated with an apparent Bmax of 2.01 mol per mole of the S-sulfonated TTR and apparent KD of 7.75x10(-6) M. On the other hand, the Bmax of cysteinyl TTR was1.38, and its KD was 3.52x10(-6) M while the Bmax of reduced TTR was 0.86, and its KD was 2.86x10(-6) M. Moreover, we detected poitive amyloid fibril staining using Thioflavin T and Congo red with the S-sulfonated TTR but not with untreated or reduced TTR by microscopic fluorescent analysis. After modification of TTR in vitro, oligomers resisted reduction and denaturation was irreversibly induced, and which contributed differences in the Western blotting patterns obtained with four anti-TTR antibodies. In conclusion, thisstudy showed that the formation of S-sulfonation of TTR through oxidative modifications of the thiol residue on the 10th cysteine of TTR is an important trigger step in the formation of transthyretin-related amyloid fibril.
|
