Could an Infection Trigger Alzheimer’s Disease?
Author: May Thongthum
Researchers and scientists have been debating for a decade over the connection between microbial infection and Alzheimer’s disease. In this article, Alison Abbot gathered a series of studies, research papers and arguments to tell the story of why neuroscientists are now starting to support the idea that microbes can cause the onset of dementia and Alzheimer’s disease. Many current researches aim to prove that Alzheimer’s results from a build-up of sticky, soluble proteins called amyloid-peptides in the spaces in brain cells, which clump into plaques and cause inflammation, killing neurons (See Figure.2). Researchers have proposed several microbes as triggers of Alzheimer’s including three human herpes viruses and three bacteria.
A team of scientists at the biotech firm Genentech in California, showed that a mutation in a gene PILRA, which usually helps herpes enter neurons, is associated with reduced risk of Alzheimer’s. The researchers say the mutation might prevent this entry. More interestingly, a paper from Yue-Ming Li at Cornell University published in 2020 reveals a mechanism that might link neuroinflammation to amyloid-production. The team found that a protein called IFLTM3 is activated when viruses enter the brain. The protein then binds to one of the amyloid-making enzymes, called γ-secretase, and increases amyloid production. Moreover, they found that a cytokine (inflammation-boosting molecule) called interferon increased levels of both IFTIM3 and amyloid-. All of these findings suggest that the protein IFTIM3 could act as a link between inflammation and the amyloid production. Citation: Abbott, A. (2020, November 04). Are infections seeding some cases of Alzheimer’s disease?
References:
Figure Retrieved from Hur JY, Frost GR, Wu X, Crump C, Pan SJ, Wong E, Barros M, Li T, Nie P, Zhai Y, Wang JC, Tcw J, Guo L, McKenzie A, Ming C, Zhou X, Wang M, Sagi Y, Renton AE, Esposito BT, Kim Y, Sadleir KR, Trinh I, Rissman RA, Vassar R, Zhang B, Johnson DS, Masliah E, Greengard P, Goate A, Li YM. The innate immunity protein IFITM3 modulates γ-secretase in Alzheimer’s disease. Nature. 2020 Oct;586(7831):735-740. doi: 10.1038/s41586-020-2681-2. Epub 2020 Sep 2. PMID: 32879487.
Abbott, A. (2020, November 04). Are infections seeding some cases of Alzheimer’s disease? Retrieved November 14, 2020, from https://www.nature.com/articles/d41586-020-03084-9
