By Kim Tong-hyung
Staff Reporter
Scientists have reported on a gene newly associated with Alzheimer's disease, saying that the discovery could help efforts to find a cure for the condition.
The research team, led by Seoul National University (SNU) Professor Suh Yoo-hun, said that the expression of the S100ap (S100 calcium binding protein A9) gene, also known as calgranulin B, was found to dramatically increase in the brains of Alzheimer's patients.
The study, which will be published in the online version of peer-review journal, PLoS ONE (Public Library of Science ONE), is the first to establish a link between the S100ap gene and the disease, Suh said.
The research also suggests the possibility of therapies based on using small interfering RNA (siRNA) to suppress the gene, an approach that showed promise in tests with laboratory mice.
``The deterioration of brain cells in the transgenic laboratory mice was slowed after an injection of siRNA. This gives the study important meaning, as it suggests the possibility of developing new drugs based on materials that suppress the S100a9 gene, which could help prevent or slow Alzheimer's,'' Suh said.
SiRNA, also known as silencing RNA, are a class of double-stranded RNA molecules that are involved in the RNA interference (RNAi) mechanism, which interferes with the expression of specific genes.
RNAi, considered among the most important breakthrough in recent findings, work by switching off individual genes, and scientists have been considering more ways to exploit the mechanism to target and suppress certain medical conditions.
The S100a9 is a member of the S100 family of proteins that are localized in the nucleus and membrane of a wide range of cells, and bind with calcium within those cells.
Although the gene is regarded as a marker protein for a number of inflammatory diseases in humans, such as rheumatoid arthritis, its exact functions have yet to be detailed.
Suh claims that suppressing S100a9 expression through the use of SiRNA would enhance chances of preventing Alzheimer's.
The delivery of SiRNA lowers cell levels of oxygen free radicals, known to cause cumulative damage within cells that results in Alzheimer's and other disorders.
The SiRNA treatment also suppresses pro-inflammatory cytokines, which are related to cardiovascular disease, insulin resistance and diabetes, Suh said.
By injecting ShRNA (short hairpin RNA) into the brains of mice genetically conditioned to carry human Alzheimer's disease, Suh's team successfully lowered the levels of beta-amyloid protein, which normally leads to nerve cell death in the brain.