Mitochondria-induced inflammation: the dark side T of a cell's
"powerhouse"
he word “immunity” conjures up an image of our body fighting against infections. We picture our immune cells heroically battling against foreign, unwanted substances – viruses and bacteria – that have breached our barriers and invaded our anatomical space. Most of us love the classic tale of “good” versus “bad”. But what about the more twisted, exciting tale of “good-turned-bad”? Some systems designed to ensure our body’s survival can become dysfunctional and trigger an unnecessary immune response against the body’s own cells. One of such essential systems are the mitochondria – organelles or structures inside each cell that generate chemical energy required to fuel cellular processes. The mitochondria use the tricarboxylic acid (TCA) cycle and electron transport chain to convert nutrients into adenosine triphosphate (ATP) molecules. Energy or ATP production is undeniably their most well-known function; however, the mitochondria carry out multiple other tasks to maintain cell survival. Mitochondrial products are used to make amino acids, nucleotides, and lipids – the building blocks of proteins, DNA, and cell membranes, respectively. For example, citrate and alpha ketoglutarate are both TCA cycle metabolites produced by the mitochondria. In addition to participating in the TCA cycle, citrate is involved in synthesizing fatty acids and cholesterol while alpha ketoglutarate is converted to glutamate – the precursor to amino acids glutamine, alanine, and aspartate. The responsibilities of mitochondria extend far beyond energy production or the synthesis of essential molecules. Mitochondria can indirectly induce inflammation, alerting the immune system of infections and setting it to “attack” mode. Upon infection, a cell usually dies and bursts open, releasing its contents for adjacent
10 IMMpress Vol. 11 No. 2 2023
