Morphine, a potent opiate, is the gold standard in clinical medicine for relieving agonizing pain. But it is highly addictive and, outside of the clinic, plays a role in the transmission of the human immunodeficiency virus through needle sharing. Researchers have known that morphine suppresses the immune system but haven’t understood how the drug causes changes at the molecular level. A team led by Joseph M. McCune at the University of California at San Francisco and Richard D. Smith at the Pacific Northwest National Laboratory addressed this question in a recent paper in Molecular & Cellular Proteomics (1). They studied three African green monkeys and three pigtailed macaques, chosen because they differ in their susceptibility to simian immunodeficiency virus, the primate version of HIV. The investigators quantified differences in the proteomes and immune responses at the organ, individual and species levels in both groups in response to morphine. As expected, both primate species showed decreased immune responses. “However, at the proteome level, we were surprised at the magnitude, in terms of numbers, of proteins that significantly changed in abundance across all tissues and fluids,” says Smith. This observation suggested that there were different mechanisms at play to give the same immunosuppressive response to morphine. Because their systems-biology approach generated a detailed map of the molecular changes when a SIV-infected host ingests morphine, Smith says, the investigators can start exploring how the suppressed immune system affects other types of infections.
- 1. Brown, J.N. Mol. Cell. Proteomics. DOI: 10.1074/ mcp.M111.016121 (2012)
Rajendrani Mukhopadhyay (email@example.com) is the senior science writer for ASBMB Today and the technical editor for The Journal of Biological Chemistry. Follow her on Twitter at www.twitter.com/rajmukhop.