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Improved spatial learning and memory by perilla diet is correlated with immunoreactivities to neurofilament and α-synuclein in hilus of dentate gyrus.

Lee J, Park S, Lee JY, Yeo YK, Kim JS, Lim J - Proteome Sci (2012)

Bottom Line: Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein.Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament.Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Major in Food Biomaterials, Kyungpook National University, Daegu, 702-701, South Korea. jkylim@knu.ac.kr.

ABSTRACT

Background: Perilla (Perilla frutescens) oil is very rich in α-linolenic acid, an omega-3 fatty acid. As it is widely reported that omega-3 fatty acid supplementation improves cognitive function in children and adults, feeding rats with perilla diets followed by analysis of proteomic changes in the hippocampus can provide valuable information on the mechanism of learning and memory at the molecular level. To identify proteins playing roles in learning and memory, differentially expressed proteins in the hippocampus of the 5 week old rats fed perilla diets for 3 weeks or 3 months were identified by proteomic analysis and validated by immunological assays.

Results: The perilla diet groups showed improved spatial learning and memory performances in a T-maze test. They also displayed elevated level of 22:6n-3 fatty acid, an omega-3 fatty acid (p<0.05), in the brain compared to the control diet group. Quantitative proteomic analysis using 2-D gels as well as functional annotation grouping with the differentially expressed proteins in the hippocampus showed that those proteins involved in cytoskeleton and transport were the major differentially expressed proteins in the 3-week group, whereas those involved in energy metabolism, neuron projection and apoptosis in addition to cytoskeleton and transport were the major ones in the 3 month group. Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein. Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament. Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

Conclusion: Improved cognitive function upon administration of n-3 fatty acid-rich perilla diet is associated with the differential expression of hippocampal proteins related to cytoskeleton, energy metabolism, transport, neuro-projection, and apoptosis. Particularly, the enhanced immunoreactivities to α-synuclein and neurofilament in the hilus of dentate gyrus suggest that perilla diet supplementation promotes neuronal signaling and alters synaptic plasticity for improved learning and memory.

No MeSH data available.


Related in: MedlinePlus

Western blotting analysis on the hippocampus of rats fed perilla diets for 3 weeks (3W) and 3 months (3M).A. The bands of hippocampal proteins separated on SDS-PAGE and transferred to PVDF membrane were incubated with antibodies against AMPA receptor (AMPAR), α-synuclein (α-syn), neurofilament M (NeuroF M), and β-soluble NSF attachment protein (β-NSF) and decorated with a chemiluminescence. B. The intensities of the bands were captured with a densitometer and normalized according to that of GAPDH. The normalized band intensities were compared between control (C) and perilla (P) or perilla oil (O) diet groups, and presented as relative expressions (%) with the control group as 100%. Letters a and b on the bar graphs designate differences between the expression levels in each group with different letters for significant differences (p <0.05).
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Figure 3: Western blotting analysis on the hippocampus of rats fed perilla diets for 3 weeks (3W) and 3 months (3M).A. The bands of hippocampal proteins separated on SDS-PAGE and transferred to PVDF membrane were incubated with antibodies against AMPA receptor (AMPAR), α-synuclein (α-syn), neurofilament M (NeuroF M), and β-soluble NSF attachment protein (β-NSF) and decorated with a chemiluminescence. B. The intensities of the bands were captured with a densitometer and normalized according to that of GAPDH. The normalized band intensities were compared between control (C) and perilla (P) or perilla oil (O) diet groups, and presented as relative expressions (%) with the control group as 100%. Letters a and b on the bar graphs designate differences between the expression levels in each group with different letters for significant differences (p <0.05).

Mentions: Since AMPA receptor subunits are essential for hippocampal synaptic plasticity, spatial learning and memory, as well as long term potentiation induction and maintenance[15-17], an antibody against AMPA receptor was used to investigate improved spatial learning and memory in rats supplemented with perilla-diets. After 3 weeks of perilla-diet intake, there was a significant increase in AMPA receptor expression, a positive control for learning and memory improvement, in the hippocampus (Figure 3). AMPA receptor protein was also differentially expressed in the hippocampus of rats supplemented with perilla-diets for 3 months. α-synuclein protein showed a good correlation with the proteomic data from Western blotting analysis. Protein expression in the hippocampus significantly increased upon both perilla- and perilla oil-diet supplementation for 3 weeks or 3 months. Neurofilament was down-regulated in both the perilla-diet and perilla oil-diet groups after 3 weeks, but it was up-regulated in the 3 month perilla oil-diet group. β-Soluble NSF protein showed slight down-regulation in the 3 week samples of perilla-diet group but up-regulation in the 3 month samples of both perilla- and perilla oil-diet groups. Overall, the fold changes of expression level in AMPA receptor, α-synuclein, neurofilament, and β-soluble NSF protein were correlated with the proteomic data and were always greater in the perilla oil-diet group compared to perilla-diet group in Western blotting analysis.


Improved spatial learning and memory by perilla diet is correlated with immunoreactivities to neurofilament and α-synuclein in hilus of dentate gyrus.

Lee J, Park S, Lee JY, Yeo YK, Kim JS, Lim J - Proteome Sci (2012)

Western blotting analysis on the hippocampus of rats fed perilla diets for 3 weeks (3W) and 3 months (3M).A. The bands of hippocampal proteins separated on SDS-PAGE and transferred to PVDF membrane were incubated with antibodies against AMPA receptor (AMPAR), α-synuclein (α-syn), neurofilament M (NeuroF M), and β-soluble NSF attachment protein (β-NSF) and decorated with a chemiluminescence. B. The intensities of the bands were captured with a densitometer and normalized according to that of GAPDH. The normalized band intensities were compared between control (C) and perilla (P) or perilla oil (O) diet groups, and presented as relative expressions (%) with the control group as 100%. Letters a and b on the bar graphs designate differences between the expression levels in each group with different letters for significant differences (p <0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539918&req=5

Figure 3: Western blotting analysis on the hippocampus of rats fed perilla diets for 3 weeks (3W) and 3 months (3M).A. The bands of hippocampal proteins separated on SDS-PAGE and transferred to PVDF membrane were incubated with antibodies against AMPA receptor (AMPAR), α-synuclein (α-syn), neurofilament M (NeuroF M), and β-soluble NSF attachment protein (β-NSF) and decorated with a chemiluminescence. B. The intensities of the bands were captured with a densitometer and normalized according to that of GAPDH. The normalized band intensities were compared between control (C) and perilla (P) or perilla oil (O) diet groups, and presented as relative expressions (%) with the control group as 100%. Letters a and b on the bar graphs designate differences between the expression levels in each group with different letters for significant differences (p <0.05).
Mentions: Since AMPA receptor subunits are essential for hippocampal synaptic plasticity, spatial learning and memory, as well as long term potentiation induction and maintenance[15-17], an antibody against AMPA receptor was used to investigate improved spatial learning and memory in rats supplemented with perilla-diets. After 3 weeks of perilla-diet intake, there was a significant increase in AMPA receptor expression, a positive control for learning and memory improvement, in the hippocampus (Figure 3). AMPA receptor protein was also differentially expressed in the hippocampus of rats supplemented with perilla-diets for 3 months. α-synuclein protein showed a good correlation with the proteomic data from Western blotting analysis. Protein expression in the hippocampus significantly increased upon both perilla- and perilla oil-diet supplementation for 3 weeks or 3 months. Neurofilament was down-regulated in both the perilla-diet and perilla oil-diet groups after 3 weeks, but it was up-regulated in the 3 month perilla oil-diet group. β-Soluble NSF protein showed slight down-regulation in the 3 week samples of perilla-diet group but up-regulation in the 3 month samples of both perilla- and perilla oil-diet groups. Overall, the fold changes of expression level in AMPA receptor, α-synuclein, neurofilament, and β-soluble NSF protein were correlated with the proteomic data and were always greater in the perilla oil-diet group compared to perilla-diet group in Western blotting analysis.

Bottom Line: Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein.Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament.Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

View Article: PubMed Central - HTML - PubMed

Affiliation: Major in Food Biomaterials, Kyungpook National University, Daegu, 702-701, South Korea. jkylim@knu.ac.kr.

ABSTRACT

Background: Perilla (Perilla frutescens) oil is very rich in α-linolenic acid, an omega-3 fatty acid. As it is widely reported that omega-3 fatty acid supplementation improves cognitive function in children and adults, feeding rats with perilla diets followed by analysis of proteomic changes in the hippocampus can provide valuable information on the mechanism of learning and memory at the molecular level. To identify proteins playing roles in learning and memory, differentially expressed proteins in the hippocampus of the 5 week old rats fed perilla diets for 3 weeks or 3 months were identified by proteomic analysis and validated by immunological assays.

Results: The perilla diet groups showed improved spatial learning and memory performances in a T-maze test. They also displayed elevated level of 22:6n-3 fatty acid, an omega-3 fatty acid (p<0.05), in the brain compared to the control diet group. Quantitative proteomic analysis using 2-D gels as well as functional annotation grouping with the differentially expressed proteins in the hippocampus showed that those proteins involved in cytoskeleton and transport were the major differentially expressed proteins in the 3-week group, whereas those involved in energy metabolism, neuron projection and apoptosis in addition to cytoskeleton and transport were the major ones in the 3 month group. Differential protein expression in the hippocampus was validated by Western blotting using four selected proteins, known to be involved in synaptic plasticity; AMPA receptor, neurofilament, α-synuclein, and β-soluble NSF attachment protein. Brain sections from the perilla-diet groups showed enhanced immunoreactivities to α-synuclein and neurofilament. Especially, neurofilament immunoreactive cells manifested longer neurite projections in the hilus of dentate gyrus of the perilla-diet groups.

Conclusion: Improved cognitive function upon administration of n-3 fatty acid-rich perilla diet is associated with the differential expression of hippocampal proteins related to cytoskeleton, energy metabolism, transport, neuro-projection, and apoptosis. Particularly, the enhanced immunoreactivities to α-synuclein and neurofilament in the hilus of dentate gyrus suggest that perilla diet supplementation promotes neuronal signaling and alters synaptic plasticity for improved learning and memory.

No MeSH data available.


Related in: MedlinePlus