Researchers at Harvard have shown that aging can be driven backwards or forwards at will in a single mouse just by manipulating the animal’s epigenetic information—how its strand of DNA is modified by the attachment of methyl molecules, like socks pinned to a clothesline. DNA methylation is the basis of the Horvath clock, used to measure aging, but the information theory of aging posits that epigenetics are not merely a marker of aging in mammals but a driver—and a reversible one, though that’s never been shown before. “We show for the first time that a main cause of aging is DNA break repair that distracts chromatin factors to smoothen the epigenetic landscape and cause cells to lose their identity,” says author David Sinclair. If this is true, he adds, then most age-related diseases may be due to a single process that could be targeted by a drug or through a gene therapy with a subset of the so-called Yamanaka factors, Oct4, Sox2, and Klf4. Cell

One of the compelling questions in longevity has been understanding how so-called senescent cells emerge throughout the body with age, how their poisonous secretions contribute to tissue dysfunction, and ultimately how to counter all that. A new study from the Chinese Academy of Sciences in Beijing shines light on the importance of non-coding DNA in this process—pieces of genetic information called human endogenous retroviruses (HERVs) that make up 8 percent of the human genome but don’t code for any human proteins. They are like ghostly remnants of our past illnesses, like evidence of ancient infections stained indelibly on our genomes. Sometimes those ghosts can be awakened—and maybe there’s a ghostbuster. The researchers showed that knocking down HERV levels with the HIV/AIDS drug abacavir in mice improved their physical health and short-term memory. While preliminary, “the findings provide fresh insights into therapeutic strategies for alleviating aging,” they write. Cell

Researchers at SUNY Stony Brook in New York have uncovered the neuroscience of what the French have known for centuries: Good taste begins in childhood. Exposing baby mice to an array of different tastes, they tracked how the pups grew to prefer sweets, how that preference actually changed their brains, altering their neural responsiveness to sucrose, and how that persisted into adulthood, profoundly affecting the development of neuronal circuits in the gustatory cortex. Culturally, the French have long embraced this approach, offering children a wide variety of foods, including a cheese course, in early infancy, sometimes while still breastfeeding. (Note to reader: For safety, never give an infant a raw milk cheese!) Science Advances

The first peptide drug was launched to great fanfare 100 years ago when 14-year-old Leonard Thompson got the first injection of insulin, Eli Lilly began mass producing it, and (at least some of) the researchers who discovered the lifesaving drug won the Nobel prize. But despite that early promise, it wasn’t until the beginning of this century that peptide drug design really took off. Currently there are more than 80 approved peptide drugs, with hundreds more in the pipeline, and if researchers at Zhejiang University in Hangzhou, China, have their way, there will be many more to come. Using machine learning to mine hundreds of billions of short, virtual peptides, the researchers identified several with potent antimicrobial promise, which they hope will accelerate the discovery of new drugs against multidrug-resistant bacteria—something we cover in our main feature story this week. Nature Biomedical Engineering

The mammalian penis achieves and maintains an erection because blood flow causes molecular changes to a tissue known as the tunica albuginea. This tissue has a double layer of stacked orthogonal rows of wavy collagen fibers, and during an erection, these fibers straighten, stretch, and you know the rest. Now researchers at South China University of Technology in Guangzhou, China, have designed an artificial tunica albuginea made from a strain-stiffening hydrogel that is physiologically safe and implantable, which they tested in pigs. The work shows promise for treating some forms of erectile dysfunction based on damage to the tunica albuginea as well as inspiring the design of electronic skins, wearable devices, implantable sensors, or new types of soft robots capable of stiffening on demand. Matter

Breathe! That basic guidance of yoga gurus, meditation masters, and spiritual teachers since ancient times may enjoy a solid basis in a real physiological phenomenon tied to lowering stress, according to a small randomized, controlled clinical trial reported this week. Researchers at Stanford University enrolled 108 people into four arms of a trial where they did a daily five-minute period of mindfulness meditation or an equivalent amount of carefully controlled breathing in one of three ways. One group practiced “cyclic sighing,” which emphasizes long exhalations. The next did “box breathing” where inspiration equals expiration. The third practiced a version of in-through-the-nose-out-through-the-mouth, emphasizing long breaths and short exhales. They found that the breathwork produces greater improvement in mood than mindfulness meditation—especially the long exhalation form. Cell Reports Medicine