Researchers at the University of California, Riverside recently reported the results of a study looking at the effects of interferon-β (IFNβ) on the brain in a mouse model of NeuroHIV, which refers to the effects of HIV infection on the brain or central nervous. They found that higher or lower than normal levels of IFNβ, a small protein involved in cell signaling and the body's natural defense against viral infections, affect the brain in a sex-dependent fashion.
When infection-induced IFNβ levels are high, the brains of both females and males are protected. However, if IFNβ production is absent or too low, HIV can compromise brain function right away in both sexes. The researchers also found that the absence of IFNβ changes the production of nerve cell components in a sex-dependent manner. In females, it reduces dendrites in the cerebral cortex, while in males, it diminishes presynaptic terminals in the hippocampus.
Paradoxically, the damage to presynaptic terminals by HIV is diminished when IFNβ is absent, with the reduction of injury more pronounced in males. The researchers explain that normal levels of IFNβ are required for normal memory function and that the absence of IFNβ affects the brain differently in females and males.
The findings, published in Brain, Behavior, and Immunity, are especially significant because the mouse model of NeuroHIV used in the study shares key features of brain injury and compromised function with people living with HIV infection. The researchers plan to confirm their findings in tissues from people living with HIV and ultimately develop IFNβ as a therapy for patients with NeuroHIV.