Mitochondrial DNA: Definition, Function, and Examples

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Mitochondrial DNA Definition

We frequently hear that stress is disturbing because it has the potential to make us sick if it becomes persistent and overwhelming. Independent studies appear to have hinted at a biological link, showing that stress might induce biological damage and potentially lead to certain illnesses. Furthermore, mitochondrial DNA — the mitochondrion’s genome — appears to play a role.

Features of Mitochondrial DNA

The mitochondrion (plural: mitochondria) is a cellular organelle that provides chemical energy for a variety of biological functions. This rod-shaped structure within the cell is responsible for the production of ATP, the cell’s primary energy source.

As a result, the mitochondrion is regarded as the cell’s “powerhouse.” Glucose (a monosaccharide) is “churned” during cellular respiration to extract energy, typically in the form of ATP.

To begin, glucose is converted to pyruvate by a sequence of processes. It then converts pyruvate to acetyl coenzyme A for oxidation via an enzyme-driven cyclic process known as the Krebs cycle.

Finally, the electron transport chain is involved in a series of events (redox reactions) that result in the synthesis of ATPs (via chemiosmosis).

Mitochondrial DNA is a kind of genetic material found only in mitochondria. As a result, the mitochondrion is thought to be a semi-autonomous, self-replicating organelle.

It can make its own RNAs and proteins, for example. In general, we get the mitochondrial DNA from our mothers, whereas we receive the nuclear genome from both parents.

Mitochondrial DNA Fate During Stress

When faced with a stressful circumstance, our bodies react instinctively. We have a tendency to exhale quickly. The pulse becomes erratic. The muscles in our bodies tighten up. We also perspire heavily. All of these reactions (also known as “fight-or-flight”) can be difficult to manage since they need a lot of energy.

We become fatigued after being stimulated for a long time. Stress sets in sooner or later, and it has a negative impact on our health. The mitochondria work for a long period merely to keep up with the surge in energy demand. As a result, individuals become sensitive to the effects of excessive labour.

Inconveniently, unlike the nucleus, mitochondria have limited repair capabilities. Finally, the organelle is disrupted, allowing mitochondrial DNA to leak into the cytoplasm. The genetic material eventually makes its way into the circulation, where it becomes genet.

Mitochondrial DNA Cast-offs

The expelled mitochondrial DNA appears to degrade into genetic trash, and stress may play a role in this. A succession of investigations led to the development of this hypothesis. To begin with, Gong et al. discovered that persistent moderate stress caused mitochondrial damage in the hippocampus, hypothalamus, and cortex of mice.

Second, another group of researchers (Lindqvist et al.) discovered that people who had recently attempted suicide had greater plasma levels of freely circulating mitochondrial DNA in their blood than healthy people.

Finally, comparable effects were seen in people exposed to a stressful scenario by Martin Picard (a psychobiologist at Columbia University) and his team. As a result, their volunteers, who were all healthy men and women, were asked to defend themselves against a bogus charge.

Before and after the interview, blood samples were collected. The researchers discovered that 30 minutes after the test, the mitochondrial DNA in the subjects’ blood rose twofold. Picard speculated that mitochondrial DNA may have functioned as a hormone. Furthermore, he hypothesised that the ejection of these genetic outcasts resembled the release of cortisol by adrenal gland cells in reaction to stress.

Mitochondrial DNA as an Inflammatory Factor

Inflammatory responses were caused by circulating mitochondrial DNA, according to Zhang et al. As a result, the genetic by-products can attach to TLR9 (an immune cell receptor). This binding may have prompted the immune cell to react similarly to how it reacts to antigens.

It might have caused the cell to produce cytokines, which signal additional immune cells to come to the scene. So far, these hypotheses based on separate research have revealed the possibility of direct biological harm as a result of stress. Stress may have a role in the emergence of ill-health problems, according to scientific evidence.

One of these is the rise in circulating mitochondrial DNA cast-offs. In an article on mental health published in Scientific American, further facts and research on mitochondrial DNA are detailed.

Mitochondrial DNA Citations
  • Mitochondrial DNA Integrity: Role in Health and Disease. Cells . 2019 Jan 29;8(2):100.
  • Mitochondrial DNA maintenance defects. Biochim Biophys Acta Mol Basis Dis . 2017 Jun;1863(6):1539-1555.
  • Mitochondrial DNA: Distribution, Mutations, and Elimination.Cells . 2019 Apr 25;8(4):379.
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