Limits...
Synchrotron FTIR micro-spectroscopy for structural analysis of Lewy bodies in the brain of Parkinson's disease patients.

Araki K, Yagi N, Ikemoto Y, Yagi H, Choong CJ, Hayakawa H, Beck G, Sumi H, Fujimura H, Moriwaki T, Nagai Y, Goto Y, Mochizuki H - Sci Rep (2015)

Bottom Line: Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients.Our results showed a shift in the infrared spectrum that indicates abundance of a β-sheet-rich structure in LBs.Also, 2D infrared mapping of LBs revealed that the content of the β-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.

ABSTRACT
Lewy bodies (LBs), which mainly consist of α-synuclein (α-syn), are neuropathological hallmarks of patients with Parkinson's disease (PD). The fine structure of LBs is unknown, and LBs cannot be made artificially. Nevertheless, many studies have described fibrillisation using recombinant α-syn purified from E. coli. An extremely fundamental problem is whether the structure of LBs is the same as that of recombinant amyloid fibrils. Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients. Our results showed a shift in the infrared spectrum that indicates abundance of a β-sheet-rich structure in LBs. Also, 2D infrared mapping of LBs revealed that the content of the β-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

No MeSH data available.


Related in: MedlinePlus

Visible and FTIR images of typical LBs in the substantia nigra of the midbrain derived from the 83-year-old female PD patient.Different LBs and different scanning steps are shown. Shown from left to right are a microscope image, the amount of total proteins, the proportion of β-sheet structures, and the amount of lipids. The colour bar indicates low (blue) to high (red) contents. The area shaded with green was scanned with 3- to 5-μm steps. (A) 4-μm step, 12 × 11 pixels = 48 × 44 μm2. (B) 5-μm step, 8 × 9 pixels = 40 × 45 μm2. (C) 3-μm step, 14 × 17 pixels = 42 × 51 μm2. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4664933&req=5

f5: Visible and FTIR images of typical LBs in the substantia nigra of the midbrain derived from the 83-year-old female PD patient.Different LBs and different scanning steps are shown. Shown from left to right are a microscope image, the amount of total proteins, the proportion of β-sheet structures, and the amount of lipids. The colour bar indicates low (blue) to high (red) contents. The area shaded with green was scanned with 3- to 5-μm steps. (A) 4-μm step, 12 × 11 pixels = 48 × 44 μm2. (B) 5-μm step, 8 × 9 pixels = 40 × 45 μm2. (C) 3-μm step, 14 × 17 pixels = 42 × 51 μm2. Scale bar, 10 μm.

Mentions: Figure 5 shows 2D mapping of components of the FTIRM spectra for sections of the brain of a PD patient with typical mature LBs. The amount of total proteins was high in the core of LBs (Fig. 5, Protein). This result is consistent with the images obtained with HE staining and EM. In contrast, the proportion of β-sheet structures was low in the core and high in the halo (Fig. 5, β-sheet). This suggests that the halo includes more fibril-like structure than the core. On the other hand, lipids tended to be concentrated in the core of LBs (Fig. 5, Lipid). Among the twenty LBs studied in this work, eight did not show a concentrated protein-rich region. Since such a structure is inconsistent with EM images of typical LBs, we consider this due to technical difficulties associated with the sample preparation: thickness may not be uniform in the section, or part of the section may have been deformed or split during sectioning, staining or dehydration. Seven (58%) in the well-prepared twelve images showed the same distribution of protein, β-sheet and lipid as described above. The remaining five (42%) showed a low content of lipid and a rather high content of β-sheet in the core (Fig. S2).


Synchrotron FTIR micro-spectroscopy for structural analysis of Lewy bodies in the brain of Parkinson's disease patients.

Araki K, Yagi N, Ikemoto Y, Yagi H, Choong CJ, Hayakawa H, Beck G, Sumi H, Fujimura H, Moriwaki T, Nagai Y, Goto Y, Mochizuki H - Sci Rep (2015)

Visible and FTIR images of typical LBs in the substantia nigra of the midbrain derived from the 83-year-old female PD patient.Different LBs and different scanning steps are shown. Shown from left to right are a microscope image, the amount of total proteins, the proportion of β-sheet structures, and the amount of lipids. The colour bar indicates low (blue) to high (red) contents. The area shaded with green was scanned with 3- to 5-μm steps. (A) 4-μm step, 12 × 11 pixels = 48 × 44 μm2. (B) 5-μm step, 8 × 9 pixels = 40 × 45 μm2. (C) 3-μm step, 14 × 17 pixels = 42 × 51 μm2. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664933&req=5

f5: Visible and FTIR images of typical LBs in the substantia nigra of the midbrain derived from the 83-year-old female PD patient.Different LBs and different scanning steps are shown. Shown from left to right are a microscope image, the amount of total proteins, the proportion of β-sheet structures, and the amount of lipids. The colour bar indicates low (blue) to high (red) contents. The area shaded with green was scanned with 3- to 5-μm steps. (A) 4-μm step, 12 × 11 pixels = 48 × 44 μm2. (B) 5-μm step, 8 × 9 pixels = 40 × 45 μm2. (C) 3-μm step, 14 × 17 pixels = 42 × 51 μm2. Scale bar, 10 μm.
Mentions: Figure 5 shows 2D mapping of components of the FTIRM spectra for sections of the brain of a PD patient with typical mature LBs. The amount of total proteins was high in the core of LBs (Fig. 5, Protein). This result is consistent with the images obtained with HE staining and EM. In contrast, the proportion of β-sheet structures was low in the core and high in the halo (Fig. 5, β-sheet). This suggests that the halo includes more fibril-like structure than the core. On the other hand, lipids tended to be concentrated in the core of LBs (Fig. 5, Lipid). Among the twenty LBs studied in this work, eight did not show a concentrated protein-rich region. Since such a structure is inconsistent with EM images of typical LBs, we consider this due to technical difficulties associated with the sample preparation: thickness may not be uniform in the section, or part of the section may have been deformed or split during sectioning, staining or dehydration. Seven (58%) in the well-prepared twelve images showed the same distribution of protein, β-sheet and lipid as described above. The remaining five (42%) showed a low content of lipid and a rather high content of β-sheet in the core (Fig. S2).

Bottom Line: Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients.Our results showed a shift in the infrared spectrum that indicates abundance of a β-sheet-rich structure in LBs.Also, 2D infrared mapping of LBs revealed that the content of the β-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.

ABSTRACT
Lewy bodies (LBs), which mainly consist of α-synuclein (α-syn), are neuropathological hallmarks of patients with Parkinson's disease (PD). The fine structure of LBs is unknown, and LBs cannot be made artificially. Nevertheless, many studies have described fibrillisation using recombinant α-syn purified from E. coli. An extremely fundamental problem is whether the structure of LBs is the same as that of recombinant amyloid fibrils. Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients. Our results showed a shift in the infrared spectrum that indicates abundance of a β-sheet-rich structure in LBs. Also, 2D infrared mapping of LBs revealed that the content of the β-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

No MeSH data available.


Related in: MedlinePlus