| Popis: |
The cells of the vertebrate immune system provide protection from infection by activating a variety of defense mechanisms. During activation, cells may grow in size, proliferate, and produce effector molecules, all of which represent energetically demanding processes. Failure to meet the energetic and biosynthetic demands may lead to immune dysfunction and disease. A common feature of immune cell activation is increased uptake and utilization of the amino acid glutamine. Glutamine is a key metabolic intermediate, allowing it to serve multiple roles during immune activation. In lymphocytes, increased glutamine uptake may provide biosynthetic precursors, via entry into the citric acid cycle, and may also serve as an exchange substrate for uptake of other amino acids. In macrophages, high glutamine import rates are required for efficient phagocytosis of opsonized particles. Glutamine can also serve as a biosynthetic precursor for arginine, and is able to support nitric oxide synthesis when arginine levels are low. In neutrophils, glutamine is required for production of reactive oxygen and nitrogen species, but also for maintaining pools of reduced glutathione, helping maintain neutrophil viability. Overall, glutamine represents a key amino acid in supporting the activation of immune cells, and represents a potential therapeutic target for both suboptimal and hyperactive immune responses. |
