High mitochondrial temperature is maintained in cells subjected to metabolic stress
Together with colleagues in four countries, Mügen Terzioglu and Howy Jacobs from Tampere University’s Faculty of Medicine and Health Technology have just published a paper in the leading bioscience journal eLife reporting extraordinary findings on the temperature of mitochondria in human and animal cells.
Corroborating their own preliminary observations, first published in 2018, that mitochondria are maintained at around 50 ºC, they have now demonstrated this high mitochondrial temperature using two independent methods, in a range of different cultured cells from humans, mice and the fruit-fly Drosophila.
Furthermore, they have shown that when external metabolic stresses are applied to cells, such as by toxins that disrupt cellular energy transactions or by changes in nutrient availability, mitochondrial metabolism is remodeled, so as to maintain a temperature about 15 ºC warmer than the cell’s external environment.
To put this in context, while our bodies as a whole are kept at a steady 37 ºC, with even a small increase perceived as fever, the energy factories inside our cells are much hotter, operating at the temperature of a typical cup of freshly made coffee. Radiating heat to the rest of the cell appears to be one of the core functions of mitochondria, which are not just supplying energy for other processes, such as muscle contraction or electrical signaling in nerve cells.
There are huge implications of these findings for understanding disease processes, as well as how cells and organisms cope with fluctuations in the external environment. If the ’heat-work balance’ becomes disturbed, many vital physiological functions are likely to suffer.
The next steps in this research are to pinpoint the molecular machineries that monitor mitochondrial temperature and modulate mitochondrial heat output in response to cellular needs.
“This opens a whole new chapter in biochemistry and physiology and may require us to revise a lot of basic ’textbook’ knowledge”, Howy Jacobs says.
Further information
Howy Jacobs
howard.jacobs [at] tuni.fi (howard[dot]jacobs[at]tuni[dot]fi)
Terzioglu M, Veeroja K, Montonen T, Ihalainen TO, Salminen TS, Bénit P, Rustin P, Chang Y-T, Nagai T, Jacobs HT (2023) Mitochondrial temperature homeostasis resists external metabolic stresses. ELife 12, RP89232. doi: 10.7554/eLife.89232.3.
Chrétien D, Bénit P, Ha H-H, Keipert S, El-Khoury R, Chang Y-T, Jastroch M, Jacobs HT, Rustin P, Rak M (2018) Mitochondria are maintained physiologically at close to 50 ºC. PLoS Biol. 16, e2003992. doi: 10.1371/journal.pbio.2003992.
