A Psychobiologist Explains How Mitochondria Impact Your Health

Remember mitochondria? Those little “powerhouses” of the cell that many of us learned about in high school biology? It turns out they do a lot more than provide energy for cellular functions. In fact, Martin Picard, PhD, associate professor of behavioral medicine at the Vagelos College of Physicians and Surgeons, calls mitochondria the “CEO of the cell.”

Dr. Picard explains why he got interested in mitochondria, how they network throughout the body, and what role they play in helping us function at our best.

Most of us first learned about mitochondria in school. What are mitochondria?

Mitochondria are small living creatures within our cells that look like sausages. They are extremely dynamic, always fusing with each other to make longer ones, and breaking off to make shorter ones. Mitochondria are responsible for transforming energy from the food you eat into energy your cells use to fuel many, many functions.

Within mitochondria are tiny folds called cristae. When we talk about mitochondria as the “powerhouse” of the cell, we’re talking about what happens between the cristae. This is where nutrient molecules in the food you eat combine with oxygen to produce the energy your cells and your body need.

Could you describe the initial observation you made in 2015 that supercharged your interest in mitochondria?

Sure! At the time, I was working as a postdoc in the lab of Doug Wallace, PhD, and we were experimenting with a cutting-edge 3-D imaging technology. We were using the technology to image mitochondria of heart muscle in mice that had heart failure because we suspected their mitochondria were sick.

What I noticed shocked me. The cristae of neighboring mitochondria aligned as if to support each other, and as I watched, the mitochondria appeared to talk to each other. That was the first hint that mitochondria are “social.” It was this physical alignment among separate mitochondria that got me thinking that maybe mitochondria do more than transform energy; maybe they operate as a living, communicating network.

In a recent Scientific American article, you refer to mitochondria as the “CEO of the cell.” What do you mean by that?

So, your ninth-grade science teacher wasn’t wrong when they called mitochondria the “powerhouses” of the cell. Mitochondria do provide energy for our cells and our bodies. However, I prefer to call mitochondria the “processor of the cell,” or better, “CEO of the cell” for Chief Executive Organelle, a phrase from my colleague Tim Shutt at the University of Calgary, Canada. That’s because mitochondria are also a primary vehicle for information processing. It is this information processing that has become the focus of my career and the focus of my lab.

For example, we (and other labs) have shown that mitochondria from different parts of the body communicate via hormones. How do they do this? Cortisol, the hormone that increases blood glucose levels to fuel the stress response, is made in the mitochondria of the adrenal glands, which sit on top of the kidneys. Our sex hormones—testosterone, estrogen, and progesterone—are synthesized mainly by mitochondria in the reproductive organs.

And brain mitochondria have receptors to sense both stress and sex hormones. So, we have populations of mitochondria in the adrenal glands and the sex organs that signal directly, via the blood, to mitochondria in the brain. In 2012, we suggested that the mitochondrial collective across the whole body should be called the Mitochondrial Information Processing System, or the MIPS.

Mitochondria can also give orders. A lot of people may be surprised to learn that it is a cell’s mitochondria that decide when a cell will divide or die at the end of its life cycle. If a cell’s mitochondria deem it necessary, they trigger a programmed cell death, or apoptosis—a form of self-sacrifice for the greater good of the organism.

Mitochondria really behave like the CEO of the cell: taking in information, focusing on the greater good of the organism, and delivering orders and messages to help the system thrive and function at its best.

Is it possible that certain diseases or conditions can be traced, at least in part, to an interruption or a corruption of this information processing?

Yes. One way this happens is when a cell’s unhealthy mitochondria send signals to the cell’s nucleus that turn on (or off) genes in abnormal ways. Our work previously showed that mitochondrial signals control the expression of more than two thirds of genes in the nucleus. Defective mitochondria can change which genes are expressed and to what extent, which can completely alter the nature, behavior, and resilience of cells and ultimately of the whole organism.

Also, abnormal mitochondrial shape and function are emerging as biomarkersand potential causes of cognitive and neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and others. Clinically, a neurobiological subtype of autism spectrum disorder involves defects in mitochondrial biology.

Mitochondria have been implicated in inflammation, too. When a cell is injured or stressed, its mitochondria leak bits of DNA. These bits of DNA are interpreted by the body’s immune system as pathogens, and the inflammatory immune response can lead to numerous chronic health conditions.

So various environmental chemicals, chronic mental stress and negative experiences, and physical inactivity may all converge to alter mitochondrial energy transformation and/or signaling, impairing coherence within the body and mind.

Are there things we can do to help our mitochondria stay healthy and perform optimally?

Definitely! Exercise is a great way to keep your mitochondria running smoothly. When you move vigorously and breathe heavily, your cells are expending a lot of energy. Your breathing provides the oxygen your mitochondria use to transform energy. At the same time, your mitochondria send signals to your cells to optimize the whole system. In response, your cells make more mitochondria!

Social connection may also be important, particularly for brain mitochondria. My colleague, Caroline Trumpff, PhD, has found a correlation between positive mental states—such as feeling purpose, optimism, and connectedness—and the health of brain mitochondria. In her study, people who had experienced more positive mental states had mitochondria in their prefrontal cortex that had been optimized for energy transformation.

Finally, pay attention to what and when you eat. It turns out that a ketogenic diet, which involves cutting out all refined sugars, limiting carbohydrates, and making up the calorie difference with fats, encourages your body to burn ketones.

Ketones, produced by your liver mitochondria, are the preferred energy source of brain mitochondria. When you cut out sugars, or when you fast for several hours, you engage the MIPS. Mitochondria begin to feed one another. If you want your brain’s mitochondria to function well, for most people, a ketogenic diet or feeling hungry occasionally are good places to start.