Science Bytes: The Autophagy Miracle

Worn-out proteins, malfunctioning organelles, invading microorganisms. You surely don’t want these junk to mess up your body. Fortunately, nature has a solution and its called autophagy.

Autophagy is a combination of two Greek words: “auto” which means “self” and “phagein” which means “to eat”. In essence, the process works like a tiny internal cleaner that sweeps up all unwelcome cells and recycles them to keep living cells healthy. As you might have guessed, a well-functioning autophagy system helps to delay aging.

Dr. Yoshinori Ohsumi, a cell biologist at the Tokyo Institute of Technology, spent years studying how human cells recycle their trash. The mechanisms of this process were mostly unknown until the early 1990s, when Ohsumi conducted a series of groundbreaking experiments with yeast, where he detected autophagy and identified genes important for the process. In 2016, he received the Nobel Prize in Physiology or Medicine for discovering the autophagy mechanism.

In this July, 2016 photo, Japanese scientist Yoshinori Ohsumi smiles at the Tokyo Institute of Technology campus in Yokohama, south of Tokyo. Ohsumi was awarded this year’s Nobel Prize in medicine on Monday, Oct. 3, for discoveries related to the degrading and recycling of cellular components. The Karolinska Institute honored Ohsumi for “brilliant experiments” in the 1990s on autophagy, the machinery with which cells recycle their content. Disrupted autophagy has been linked to various diseases including Parkinson’s, diabetes and cancer, the institute said. (Akiko Matsushita/Kyodo News via AP)

Most of the tissues in our bodies replace their cells with new ones on a regular basis. Each organ needs its own time to renew itself completely. The gist of how autophagy works is as follows. Inside the cytoplasm of every living cell are organelles called autophagosomes which continually engulf bits of cytoplasm that is clotted with unwanted proteins, damaged cell parts and invading bacteria and viruses. These “cargo” is then carried to digestive organelles called lysosomes where the trash is broken up and recycled into new cells. In short, autophagy is about removal and renewal.

Scientists have also determined that autophagy acts as a defense against viruses and bacteria. If a foreign object or organism evades the extracellular immune system and find its way into the cytoplasm, it becomes a target for the autophagy system. By the same token, when autophagy malfunctions, the consequences can be dire. These include diabetes, cancers, Alzheimer’s disease, and aging itself. Therefore, you will want to do everything you can to prolong the efficiency of this amazing cleansing process. How? Read on.

It has long been known that fasting provokes the body to break down toxic cells. When you fast, you lower your calorie intake which increases the level of nitric oxide in your body. Because nitric oxide is a molecule that helps detoxify and rejuvenate the body, increasing its level in the body helps reduce inflammation, oxidative stress and blood pressure, all of which promotes a healthier life. And possibly a longer life, too as calorie restrictions as one ages help to offset the age-related decline of the body’s functions, including that of autophagy.

Schematic Diagram of the Autophagy Process

Schematic diagram of the steps of autophagy. Autophagy begins with the formation of the phagophore or isolation membrane (vesicle nucleation step). The concerted action of the autophagy core machinery proteins at the phagophore assembly site (PAS) is thought to lead to the expansion of the phagophore into an autophagosome (vesicle elongation). The autophagosome can engulf bulk cytoplasm nonspecifically, including entire organelles, or target cargos specifically. When the outer membrane of the autophagosome fuses with an endosome (forming an amphisome before fusing with the lysosome) or directly with a lysosome (docking and fusion steps), it forms an autophagolysosome. Finally, the sequestered material is degraded inside the autophagolyosome (vesicle breakdown and degradation) and recycled.

Watch this video to discover more on autophagy and different ways of fasting.

Leave a Reply