Figure 2.

Modulation of Mitochondrial Metabolism upon Infection.

Many bacteria and viruses hijack cellular metabolism for their own benefit. Mycobacterium is the best-known bacterium that influences host metabolism by enhancing aerobic glycolysis. Epithelial cells and immune cells infected with Mycobacterium exhibit a reduction in the tricarboxylic acid (TCA) cycle and a corresponding increase in the glycolytic flux. Elevated aerobic glycolysis is also observed in Mycobacterium-infected lung granulomas in animal models of infection and in patients with active tuberculosis. Legionella also promotes glycolytic flux similar to Mycobacterium, thus enhancing aerobic glycolysis. Brucella infection promotes lactate production via aerobic glycolysis, while suppressing the TCA cycle. Chlamydia enhances the levels of the glucose transporter GLUT1, leading to augmented glucose uptake and increased glycolytic flux, which is necessary for its intracellular growth. Viruses also perturb metabolic pathways for their replication and subsequent dissemination. Herpes virus induces the TCA cycle, thereby promoting mitochondrial respiration, while Hepatitis C perturbs mitochondrial fatty acid oxidation. Created with BioRender (www.BioRender.com).