Effects of opiates and HIV proteins on neurons: the role of ferritin heavy chain and a potential for synergism

Human immunodeficiency virus 1 (HIV-1) and its associated proteins can have a profound impact on the central nervous system. Co-morbid abuse of opiates, such as morphine and heroin, is often associated with rapid disease progression and greater neurological dysfunction. The mechanisms by which HIV proteins and opiates cause neuronal damage on their own and together are unclear. The emergence of ferritin heavy chain (FHC) as a negative regulator of the chemokine receptor CXCR4, a co-receptor for HIV, may prove to be important in elucidating the interaction between HIV proteins and opiates. This review summarizes our current knowledge of central nervous system damage inflicted by HIV and opiates, as well as the regulation of CXCR4 by opiate-induced changes in FHC protein levels. We propose that HIV proteins and opiates exhibit an additive or synergistic effect on FHC/CXCR4, thereby decreasing neuronal signaling and function.