SEP 02, 2019 5:17 PM PDT

Measuring the Heat That Mitochondria Release

WRITTEN BY: Carmen Leitch

Researchers at the University of Illinois developed a minuscule probe that can take the temperature of a cell’s interior. They used it to learn more about how heat is involved in metabolism. The power-generating organelles of the cell, mitochondria (described in the video below) have a sort of internal battery, which produces heat when protons are released. The researchers were able to take measurements of this heat. The findings, which may offer new insights into obesity and cancer, have been reported in Communications Biology.

"Producing heat is part of the mitochondria's role in the center of metabolism activity," said mechanical science and engineering professor Sanjiv Sinha, who led the work. "It needs to produce the energy currency that's used for the activities in the cell, and heat is one of the byproducts, in most cases. But there is a mechanism that can ramp this process up to produce more heat when the body needs it. That's what fat cells do when they're in need of heat when the body's temperature goes down."

The fast-read thermometer probe that was created had to be long enough to get into cells while they were viewed under a microscope. But it also had to be so small that it didn’t disrupt the cell’s functions.

"Think about how we take temperature with a probe under our tongue. We are essentially doing the same, but inside a single cell," Sinha said. "And we wanted to be very fast to measure what's happening. Things happen inside the cell very quickly. It's like, if you're taking a young child's temperature, you need to do it very quickly, or they will move and it won't be accurate."

Along with with the lab of emeritus professor Rhanor Gillette, Sinha’s team tested their probe, which turned out to be surprisingly effective.

"We found some results that were completely different from what has been published before," noted Manjunath Rajagopal, a graduate student and first author of the study. "We saw a sharp temperature spike that is significantly large and short-lived - around five degrees Celsius and less than one second. The gold standard for measuring has been with fluorescence, but it is too slow to see this short, high burst of heat. Just with a simple probe measuring at high speed, we have demonstrated that we can find things that other methods have missed."

It was thought that mitochondria were producing heat as they broke down more glucose. However, the heat spikes the researchers were observing were too high for that. "It cannot be releasing that kind of energy from metabolizing stored glucose. It just didn't make sense," Sinha said. "Where is it coming from? There has to be a source of that energy."

After hypothesizing that the energy release was akin to the release of protons from a cellular battery, the team confirmed it using molecules that open membrane channels in the mitochondria.

"In the mitochondria, one part of the glucose metabolism reaction stores some of the energy as a proton battery. It pushes all the protons to one side of a membrane, which creates an energy store," Rajagopal said. "We basically short-circuited the stored energy."

The team wants to apply the probe to more types of cells, which may reveal targets for therapies. Fat cells, for example, might be stimulated to release protons as an obesity treatment.

"Cancer would be another application," Rajagopal said. "Cancer cells have a variety of reprogrammed metabolic pathways that are often driven to extremes. This probe provides us a tool to study thermal activity associated with different metabolic pathways."

Learn more about the role of mitochondria in disease from the video.

Sources: Phys.org via University of Illinois at Urbana-Champaign, Communications Biology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 09, 2020
Cell & Molecular Biology
Why Liver Gene Therapies Have Not Worked & How to Improve Them
SEP 09, 2020
Why Liver Gene Therapies Have Not Worked & How to Improve Them
Diseases that are caused by errors in a gene might be cured if we could correct those errors, or genetic mutations.
SEP 27, 2020
Microbiology
New Insight Into An Old Bacterial Pathogen
SEP 27, 2020
New Insight Into An Old Bacterial Pathogen
There are many different strains of Escherichia coli bacteria, some of which live harmlessly in the human gut. But some ...
SEP 29, 2020
Cell & Molecular Biology
What We Call Parkinson's Disease May Actually be Two Distinct Disorders
SEP 29, 2020
What We Call Parkinson's Disease May Actually be Two Distinct Disorders
Researchers have used imaging tools to show that Parkinson's disease may actually be two different diseases, one that st ...
OCT 19, 2020
Clinical & Molecular DX
Making Capillary Electrophoresis Accessible for Any Lab
OCT 19, 2020
Making Capillary Electrophoresis Accessible for Any Lab
Analyzing nucleic acids through gel electrophoresis has been a staple of genetic research for decades. But using traditi ...
OCT 18, 2020
Cell & Molecular Biology
Small RNA is Connected to Bacterial Pathogenicity
OCT 18, 2020
Small RNA is Connected to Bacterial Pathogenicity
It's thought that as much as half of the global population carries a bacterium called Helicobacter pylori in their stoma ...
NOV 22, 2020
Cell & Molecular Biology
What is ChIP-Seq and Is It Quantitative After All?
NOV 22, 2020
What is ChIP-Seq and Is It Quantitative After All?
ChIP-Seq is a tool for analyzing the interactions between DNA and the proteins that bind to it, which influences gene ac ...
Loading Comments...