Abstract
BackgroundL-methionine, the principal sulfur-containing amino acid in proteins, plays critical roles in cell physiology as an antioxidant and in the breakdown of fats and heavy metals. Previous studies suggesting the use of L-methionine as a treatment for depression and other diseases indicate that it might also improve memory and propose a role in brain function. However, some evidence indicates that an excess of methionine can be harmful and can increase the risk of developing Type-2 diabetes, heart diseases, certain types of cancer, brain alterations such as schizophrenia, and memory impairment.ResultsHere, we report the effects of an L-methionine-enriched diet in wild-type mice and emphasize changes in brain structure and function. The animals in our studypresented 1) higher levels of phosphorylated tau protein, 2) increased levels of amyloid-β (Aβ)-peptides, including the formation of Aβ oligomers, 3) increased levels of inflammatory response,4) increased oxidative stress, 5) decreased level of synaptic proteins, and 6) memory impairment and loss. We also observed dysfunction of the Wnt signaling pathway.ConclusionTaken together, the results of our study indicate that an L-methionine-enriched diet causes neurotoxic effects in vivo and might contribute to the appearance of Alzheimer’s-like neurodegeneration.Electronic supplementary materialThe online version of this article (doi:10.1186/s13024-015-0057-0) contains supplementary material, which is available to authorized users.
Highlights
L-methionine, the principal sulfur-containing amino acid in proteins, plays critical roles in cell physiology as an antioxidant and in the breakdown of fats and heavy metals
Our results showed that the brains of mice with a methionine-rich diet presented 1) increased levels of phosphorylated tau protein, 2) increased levels of amyloid-β (Aβ) peptides and Aβ oligomers, 3) neuroinflammation, 4) increased levels of nitro-tyrosinated protein, a marker of oxidative stress, 5) decreased levels of pre- and post- synaptic proteins, and 6) memory impairment accompanied by the loss of function of the Wnt signaling pathway
Several studies have demonstrated that L-methionine is an important and essential amino acid; high levels have been associated with deleterious effects [9, 10]
Summary
L-methionine, the principal sulfur-containing amino acid in proteins, plays critical roles in cell physiology as an antioxidant and in the breakdown of fats and heavy metals. Some evidence indicates that an excess of methionine can be harmful and can increase the risk of developing Type-2 diabetes, heart diseases, certain types of cancer, brain alterations such as schizophrenia, and memory impairment. Methionine and cysteine are considered to be the principal sulfur-containing amino acids in proteins, and they play critical roles in cell metabolism. Methionine metabolism begins with its conversion to homocysteine (Hcy) via its intermediate, S-adenosylmethionine (SAM). This sequence of reactions is called transmethylation, and it ubiquitously occurs in mammalian cells [14]. Methionine is a key aminoacid in humans [26, 27], a large body of evidence supports the notion that excessive uptake can become harmful, further clarifying that the way we eat is fundamental in a healthy lifestyle
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
