The study, reported in the Proceedings of the National Academy of Sciences, looked at how cigarette smoke affects retinal pigmented epithelial (RPE) cells and may contribute to age-related macular degeneration. James T. Handa, principal investigator and chief of the retina division at the Wilmer Eye Institute at Johns Hopkins University, noted that smoking is often linked to tissue damage by free radicals, and the new work also shows epigenetic changes—non-permanent shifts in gene expression—in RPE cells.
Researchers compared RPE cells from 3-month and 12-month mice after both acute and chronic smoke exposure. They used genetic sequencing at several time points and found dysfunctional RPE clusters and reduced chromatin accessibility. Chromatin is the compact structure of DNA, RNA, and proteins that controls which genes are active.
Acute smoke exposure decreased expression of core RPE function genes and of genes called hallmarks of aging, such as genomic instability, telomere shortening, and damaged mitochondria. Tests of donated human RPE cells from several donors showed many shared gene changes—1,698 genes overlapped between dysfunctional human and mouse cells. Researchers now plan to study which changes persist and how age plus continuous smoke exposure add to late-stage AMD and related problems.
Difficult words
- epigenetic — Changes in gene activity without DNA change
- chromatin — DNA and proteins packed inside the cell
- genomic — Related to an organism's complete genetic material
- telomere — End part of a chromosome that shortens
- mitochondrion — Cell parts that make energy for the cellmitochondria
- acute — Happening over a short time period
- chronic — Continuing for a long time
- dysfunctional — Not working normally or properly
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Based on the article, how might stopping smoking affect the risk of age-related eye damage? Give two reasons.
- Why do you think researchers used both younger and older mice plus donated human cells in this study?
- Researchers want to study which changes persist. What results would be most important for doctors trying to prevent late-stage macular degeneration?
Related articles
Milk glands in many mammals have receptors for H5N1
A study found that milk gland tissue from pigs, sheep, goats, beef cattle, alpacas and humans contains sialic acid receptors that can let H5N1 attach to cells. Researchers warn of surveillance and concerns about raw milk from mammals.
Wheat fiber protects mice from intestinal inflammation
Two research papers report that adding wheat fiber to the diet protects mice from intestinal inflammation. Gut bacteria release polyphenols from the fiber that reduce inflammation, and authors suggest whole-grain foods may lower IBD risk.
How Long-Term Singlehood Affects Young Adults
A study tracked more than 17,000 young people in Germany and the UK from ages 16 to 29. It found that long periods of singlehood are linked to falling life satisfaction and rising loneliness, while starting a first relationship improves well-being.
