Biologists at the University of Manchester have pinpointed why a good night's sleep truly prepares us for the day's challenges. Their groundbreaking study reveals how our body clock boosts tissue maintenance precisely when we're most active.
As we age, the body clock becomes less precise, notes lead author Professor Karl Kadler. This discovery could ultimately help unravel key aspects of aging.
The findings illuminate the body's extracellular matrix—the supportive network of connective tissues like bone, skin, tendons, and cartilage. It accounts for over half our body weight, with collagen making up half of that, fully maturing by age 17.
Two Types of Fibrils
Researchers identified two distinct collagen fibrils: the rope-like structures that weave through cells to form tissues.
Thicker fibrils, around 200 nanometers in diameter—a million times smaller than a pinhead—are permanent fixtures from age 17 onward.
Thinner 50-nanometer fibrils, however, are temporary: they degrade under daily stress but regenerate during sleep.
Using mass spectrometry and advanced volumetric electron microscopy, the team tracked mouse fibrils every four hours over two days. Disabling body clock genes caused thin and thick fibrils to merge randomly.
“Collagen is our most abundant protein, providing structure, elasticity, and strength to connective tissues,” says Professor Kadler.
“Intuitively, you'd expect wear and tear to degrade our matrix, but it doesn't. Our body clock creates sacrificial fibrils that replenish nightly, safeguarding the permanent ones.”
He elaborates: “Think of permanent bricks as the walls and sacrificial paint that needs refreshing—or like oiling a car and topping up the radiator.”
“This insight deepens our grasp of biology, from wound healing to aging processes.”
