Washington: Scientists have discovered a group of six new proteins that may help divulge secrets of how we age, potentially unlocking new insights into diabetes, Alzheimer's, cancer and other ageing-related diseases.
The tiny proteins appear to play several big roles in our bodies' cells, from decreasing the amount of damaging free radicals and controlling the rate at which cells die to boosting metabolism and helping tissues throughout the body respond better to insulin, researchers said.
The naturally occurring amounts of each protein decrease with age, leading researchers to believe that they play an important role in the ageing process and the onset of diseases linked to older age, they said.
The research team led by Pinchas Cohen, professor at the University of Southern California Leonard Davis School of Gerontology, identified the tiny proteins for the first time and observed their surprising origin from organelles in the cell called mitochondria and their game-changing roles in metabolism and cell survival.
The latest finding builds upon prior research by Cohen and his team that uncovered two significant proteins, humanin and MOTS-c, hormones that appear to have significant roles in metabolism and diseases of ageing.
Unlike most other proteins, humanin and MOTS-c are encoded in mitochondria, the structure within cells that produces energy from food, instead of in the cell's nucleus where most genes are contained.
Mitochondria have their own small collection of genes, which were once thought to play only minor roles within cells but now appear to have important functions throughout the body.
Cohen's team used computer analysis to see if the part of the mitochondrial genome that provides the code for humanin was coding for other proteins as well.
The analysis uncovered the genes for six new proteins, which were dubbed small humanin-like peptides, or SHLPs, 1 through 6.
After identifying the six SHLPs and successfully developing antibodies to test for several of them, the team examined both mouse tissues and human cells to determine their abundance in different organs as well as their functions.
The proteins were distributed quite differently among organs, which suggests that the proteins have varying functions based on where they are in the body.
Of particular interest is SHLP 2, Cohen said. The protein appears to have profound insulin-sensitising, anti-diabetic effects as well as potent neuro-protective activity that may emerge as a strategy to combat Alzheimer's disease.
He added that SHLP 6 is also intriguing, with a unique ability to promote cancer cell death and thus potentially target malignant diseases.
"The findings are an important advance that will be ripe for rapid translation into drug development for diseases of ageing," said Cohen.