Latest news with #CYP26B1
Yahoo
20-06-2025
- Science
- Yahoo
Humans Already Have the Ingredients to Regrow Limbs, Scientists Find
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Axolotls are known for their ability to grow back just about any body part that is bitten off by a predator, but the trigger for this regeneration was a mystery until now. It turns out that retinoic acid and the enzyme CYP26B1 are heavily involved in regrowing missing limbs, determining what goes where before forming new tissue. Future technology inspired by axolotls could possibly help humans regenerate limbs—we have what is needed, but need to find out how to make those pieces communicate like they do in axolotls. In the 1995 cyberpunk film Virtuosity, the genes of android villain SID 6.7 are merged with snake DNA, giving him the superhuman ability to regrow lost limbs. Axolotls can do that without even trying—in fact, it is possible for an axolotl to lose virtually any body part (even its brain and internal organs) and fully regenerate it. Mysteries surrounding these virally adorable amphibians' regenerative powers have fueled the sci-fi dreams (and frustrations) of scientists for almost two centuries, but not until recently did anyone understand the mechanism behind this ability. Now, molecular biologist James Monaghan of Northeastern University has made a breakthrough that has allowed us to identify the driving force of regeneration—and maybe, one day, we will be able to give this power to humans. Positional memory means that an axolotl somehow knows if it needs to grow back a lost finger, hand, or entire arm. This was already known to be the basic mechanism behind vertebrate regeneration, but what Monaghan found was that it begins with retinoic acid and the enzyme CYP26B1. Neither of these chemicals are exclusive to axolotls—both are also found in the human body. It is just a matter of axolotls being able to use them differently. Larger limbs at proximal sites closer to the body, such as arms, contain more retinoic acid and less CYP26B1 (which breaks the retinoic acid down). And in smaller sites further from the body, like hands, there is less retinoic acid and more CYP26B1. 'Regenerating limbs retain their proximodistal (PD) positional identity following amputation. This positional identity is genetically encoded by PD patterning genes that instruct blastema cells to regenerate the appropriate PD limb segment,' Monaghan and his team said in a study recently published in the journal Nature Communications. When a predator bites an arm (or anything else) off of an axolotl, retinoic acid is synthesized in the middle layer of skin and spreads to the limb bud. This helps generate fibroblasts, which are connective tissue cells in humans, but regenerative cells in these creatures. Fibroblasts form blastema, or limb progenitor cells, which then grow and differentiate to recreate the particular limb that is missing. Blastema mirror the behaviors of limb buds that grow as an embryo develops, and in both embryos and adult axolotls that have been injured, positional information is exchanged between stem cells in the blastema and other cells in this budding limb to ensure that the appropriate tissues regenerate where they are supposed to grow. The gene Hoxa13 activates CYP26B1, which breaks down retinoic acid where it is not needed and uses it to create a pattern for the limb being regenerated. This breakdown determines how much retinoic acid is at an amputation site and, consequently, the position and structure of the limb which is regrown. Higher levels of retinoic acid activate the Shox gene—a transcription factor that both gives directions for producing a protein that regulates what other genes do and is involved with forming the skeleton. As Monaghan found out, defects such as skeletal abnormalities can occur if this process is disrupted. Raising levels of retinoic acid in an axolotl's hand caused it to grow not just another hand, but a whole new arm. Eliminating Shox with CRISPR-Cas9 resulted in normal hands but short arms, with bones that did not harden properly. This also occurs in humans with Shox mutations. What is especially amazing about axolotls is that they regenerate the limb in the exact same form it took before amputation. Some other animals that regenerate, like lizards, may grow back the end of a missing tail, but in a simpler form than the original. Much more research will be needed to transfer this ability to humans, but the materials are there. Healing wounds without scarring might even be possible in the near future. What we need to do next to make that future a reality is find out what happens inside blastema cells during regeneration, and which parts of these cells are targeted by retinoic acid. 'If we can find ways of making our fibroblasts listen to these regenerative cues, then they'll do the rest,' Monaghan said in a recent press release. 'They know how to make a limb already because, just like the salamander, they made it during development.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
12-06-2025
- Health
- Yahoo
Axolotls' Regenerative Abilities Could Teach Scientists a Thing or Two About Medicine
Axolotls might be cute enough to feature in a wide variety of games, TV shows, and children's toy brands, but that's not all that makes them special: The species is also exceptionally good at regenerating lost limbs and organs. Thinking that these smiling salamanders might have something to teach modern medicine, researchers in Boston are unpacking the molecules responsible for axolotls' rapid regrowth. One molecule in particular could someday help heal human wounds and replace lost limbs. The molecule is retinoic acid, according to a paper published Tuesday in Nature Communications. Human bodies make retinoic acid out of vitamin A (obtained by eating fish, dairy, and vegetables) and occasionally receive it through cosmetic retinoids, which are used to treat acne. The molecule is key to cell growth, and if too much of it is absorbed during pregnancy, it can lead to serious birth defects. In axolotls, retinoic acid takes that role a step further. Biologists at Northeastern University have found that axolotls rely on a retinoic acid signaling gradient, which allows different concentrations of the molecule to work in various parts of the body. Their shoulders, for instance, contain more retinoic acid (and less of the enzyme CYP26B1, which breaks it down) than their palms. When an axolotl loses its arm, the retinoic acid in its shoulder tells its fibroblasts, or regenerative cells, how to build a new one. This axolotl is regenerating an arm after an attack. Credit: HTO/Wikimedia Commons (public domain) According to Northeastern's write-up, this discovery led the researchers to conduct experiments that were, in their words, "pretty Frankensteiny." Adding bonus retinoic acid to an axolotl's hand allowed it to grow a duplicate limb, for example. But simply injecting a human with extra retinoic acid won't allow them to generate new body parts. Now, the researchers are working to untangle "shox," short for the "short homeobox gene." This gene activates whenever retinoic acid signaling increases in an axolotl's body, suggesting that shox plays a part in limb regeneration. Indeed, removing shox from an axolotl's genome caused it to grow "very short arms," albeit with normal-sized hands. Understanding how retinoic acid and shox collaborate will be the next step toward wielding axolotl insights in human medicine. "If we can find ways of making our fibroblasts listen to these regenerative cues, then they'll do the rest," said biologist and study co-author James Monaghan. "They know how to make a limb already because, just like the salamander, they made it during development."
