MOLECULAR MECHANISMS OF OPIOIDS AS COFACTORS IN AIDS

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DESCRIPTION: Applicant's Abstract We were the first to report that HIV proteins express unique, immunoregulatory activities that may be extra-infectious mediators of the pathogenesis of AIDS. Next we studied the molecular mecnanisms underlying the effects of viral proteins in the development of the immnunodeficiency and neuropathological complications of AIDS. Also we had a long-standing interest in the role of i.v., recreational drugs as co-factors in susceptibility to and progression of HIV infections. These interests merged in a series of studies demonstrating that opioids potentiate several immunopathogenic mechanisms mediated by HIV proteins. Thus our preliminary results support the success of this proposal. Several experimental approaches will be used to determine the molecular mechanism underlying the synergy between HIV proteins and opioids. Human lymphocytes will be cultured with HIV proteins + morphine to look for further potentiation of the shift from Th-1 to Th-2 lymphocyte predominance that we showed was mediated by HIV proteins alone. This will be accomplished by examining both gene expression and production of Th-1 and Th-2 defining cytokines. Further we shall determine whether opioids synergize with HIV proteins in vitro to induce apoptosis of lymphocytes or purified microglia and astrocytes from rat brains to determine the effects of opioids and HIV proteins on the immune system and the CNS respectively. Control experiments using the mu-specific opioid antagonists, naloxone and beta funaltrexamine, will assure the specificity of opioid-mediated effects. In vivo confirmation of our in vitro CNS findings will be undertaken using our established rat mode1 wherein HIV proteins + excitatory amino acid agonists + morphine will be stereotactically injected into the dorsal hippocampus. Brain slices will be examined for gross and microscopic pathology. Identification of markers for apoptosis as well as expression of specific cytokine genes will be determined in brain sections by direct hybridization and a new, in situ, PCR method. Lastly we shall follow-up on the exciting new findings that the beta-chemokines and their receptors affect susceptibility to and progression of HIV infections. Recently, we reported that morphine modulates the expression of the beta-chemokines and their receptors. Now we shall determine the molecular mechanisms underlying these effects. Subsequent experiments will compare and contrast clinical materials from HIV- and HIV+ adults and neonates and the neuropathological studies will subsequently use human CNS tissues. Our studies on opioids as co-factors in HIV infections may yield novel therapies for the treatment of opioid-addicted, HIV-infected patients.