I have neglected my scienceblogging duties for too long, so here is a compendium of the latest and coolest news to cross my desk.
* Resveratrol, a compound found in red wine and a long-time favorite of the blog, helps keep you fit by tricking the liver into thinking that you’re fasting (subscription wall). Focusing on the resveratrol target Sirtuin 1 rather than the drug itself, a team found that fasting stimulates the liver to break down fat and cholesterol via a signal from SIRT1. This further supports the idea that the drug lengthens lifespan among a staggering number of other beneficial effects largely by “tricking” the body into acting as though it’s starving.
* Move over resveratrol! Reporting in Cell, researchers have created a mouse that lives longer, eats more, weighs less and resists the negative physical effects of stress by knocking out a brain-specific signaling molecule called type 5 adenylyl cyclase (AC5; subscription wall). If AC5 proves as easy to manipulate with drugs as SIRT1 this news could be huge for people with stress-related heart and weight problems. Which is to say quite a lot of us.
* More good news – caffeine and exercise helps a mouse lose weight! You probably knew that already. Did you know that it also protects against cancer? The researchers specifically looked at skin cancer from ultraviolet light, but I will go out on a limb and predict that a limited number of other types of cancer will also prove amenable to the jogging-and-coffee treatment. I’ll explain my reasoning after the jump.
* A new population genetics study proposes a genetic theory of autism.
* Sadly in the near future we will need more PTSD-related research, not less. In the same vein as an earlier report that an experimental drug can selectively wipe out stressful memories, researchers have recently found that a gene variant, ADRA2B, increases the vividness of emotional memories.
* As they sometimes do Humboldt squid have migrated with warm, low-oxygen waters out of the Baja area and into southern and central California. This time, however, the big squid seem to have arrived for good. What the heck is a Humboldt? Think of a mean-tempered doberman that eats everything it sees. The squid’s reputation as a man-killer is probably exaggerated but commercial fishermen won’t be happy.
Back to the point about caffeine, skin cancer made a good topic for study because like a limited subset of carcinogens, ultraviolet light promotes cancer by acting like a micro-scale DNA chainsaw. Cells cannot divide when DNA has been cut so cell division waits until repair enzymes have fixed the break. Very rarely the repair enzymes make a mistake, which can be a problem if the error happens in the right (wrong) place. Mistakes that inappropriately activate (Ras) or inactivate (p53) specific proteins often kick off a process of unregulated growth and further mutation that eventually leads to cancer.
Interestingly, we knew for a while that caffeine is both a stimulant and a very handy drug for bypassing cell cycle checkpoints. This property, cutting the regulations on cell growth, is one of the reasons why I haven’t had much coffee since I took up science as a career. This study suggests that I should regard caffeine in almost exactly the opposite light. The key is that UV-damaged cells need that arrested period so that the repair enzymes can fix broken DNA. When caffeine shortcuts the mandatory wait time the cell barrels ahead with division without waiting for the repair. Instead of (maybe) a cancer cell you have a dead cell, which is a far more manageable problem.
The caffeine trick won’t do any good for cells that have already become cancerous and it won’t prevent inherited cancers, viral cancers (e.g., human pappilomavirus) or cancers that come from spontaneous mutations in non-dividing tissue. But it will probably work as well or better than sunblock if you’re planning some time at the beach.