Cellular recycling extends health and life expectancy in mammals
Buildingon two decades of research, scientists at University of Texas Southwestern have foundthat enhancing autophagy, a process of natural "cellularhousekeeping" within our bodies, can extend the lifespan of mice by10 percent and reduce age-related illnesses. The study could serveas an important step toward treating degenerative diseases likeAlzheimer's in humans.
Autophagy(from the Greek words for "self" and "eating") is a highly-desirable physiological process that destroys aged or damagedcellular components and recycles them to build new, healthier cells.Scientists believe that one of the reasons why exerciseand calorie-restricted diets tend to improve our health and lengthen our lives is thatthey subject cells to heightened levels of stress, which in turnboosts autophagyin the body.
Unfortunately,our ability to perform this valuable "cellular spring-cleaning"declines with age. But what if that decline could be stopped?
Ina recent study, a team led by doctors SalwaSebti and Álvaro Fernández at UT Southwestern set out to findwhether artificially and permanently increasing the level ofautophagy in mice would affect their longevity and overall health.The researchers achieved this through genetic engineering, bymutating the protein Beclin-1(which helps regulate autophagy and cell death) so it would bind lesstightly to its inhibitor Bcl-2.
Asa result of this tweak, the genetically-engineered mice showedconsistently higher levels of autophagy in all their organs andthroughout their lives. Previous studies had suggested these micewere partially immune to the mouse equivalent of Alzheimer's disease,but the latest work goes into significantly more depth, suggestingthey also live about 10 percent longer lives and are generallyhealthier, since they are less likely to develop age-related cancersand pathological changes in the heart and kidneys.
"Thesestudies have important implications for human health and for thedevelopment of drugs to improve it," said Dr. Beth Levine, directorof the Center for Autopathy Research at UT Southwestern. "They showthat strategies to increase the cellular housekeeping pathway ofautophagy may retard aging and aging-related diseases."
Theresults suggest that it should be safe to permanently increaseautophagy to treat neurodegeneration and other diseases by developingdrugs that specifically target the binding between Beclin-1 andBlc-2.
Levineand her team are now working with other researchers to synthesizesuch a drug, with the intent to target human patients.
Thestudy appears in the latest edition of the journal Nature.