Enhanced anandamide degradation is associated with neuronal apoptosis induced by the HIV-1 coat glycoprotein gp120 in the rat neocortex Mauro Maccarrone,* ,  Silvia Piccirilli, Natalia Battista,à Claudio Del Duca, Giuseppe Nappi,  M. Tiziana Corasaniti,§ Alessandro Finazzi-Agro ` à and Giacinto Bagetta  , ¶ *Department of Biomedical Sciences, University of Teramo, Teramo  IRCCS C. Mondino, Santa Lucia Center for Experimental Neurobiology, Rome àDepartment of Experimental Medicine and Biochemical Sciences, University of Rome, Rome §Department of Pharmaco-Biology Sciences, University Magna Graecia of Catanzaro, Catanzaro ¶Department of Pharmaco-Biology, Calabria University at Cosenza, Cosenza, Italy Abstract Human immunodeficiency virus type-1 coat glycoprotein gp120 causes delayed apoptosis in rat brain neocortex. Here, we investigated the possible role of the endocannabinoid system in this process. It is shown that gp120 causes a time- dependent increase in the activity and immunoreactivity of the anandamide (AEA)-hydrolyzing enzyme fatty acid amide hydrolase (FAAH), paralleled by increased activity of the AEA membrane transporter and decreased endogenous levels of AEA. The AEA-synthesizing phospholipase D and the AEA- binding receptors were not affected by gp120. None of the changes induced by gp120 in the cortex were induced by bovine serum albumin, nor were they observed in the hippocampus of the same animals. Also, the activity of 5-lipoxygenase, which generates AEA derivatives able to inhibit FAAH, decreased down to approximately 25% of the control activity upon gp120 treatment, due to reduced protein level (45%). In addition, the FAAH inhibitor methyl-arachidonoyl fluorophosphonate significantly reduced gp120-induced apop- tosis in rat brain neocortex, whereas selective blockers of AEA membrane transporter or of AEA-binding receptors were inef- fective. Taken together, these results suggest that gp120, by activating FAAH, decreases endogenous levels of AEA, and the latter effect seems instrumental in the execution of delayed neuronal apoptosis in the brain neocortex of rats. Keywords: endocannabinoids, gp120, lipoxygenase, neuronal apoptosis. J. Neurochem. (2004) 89, 1293–1300. Type-1 human immunodeficiency virus (HIV-1) coat glyco- protein gp120 has been shown to cause apoptosis (pro- grammed cell death, PCD) in the brain neocortex of rats treated with a dose of 100 ng of this coat protein for seven consecutive days (Bagetta et al. 1996a,b). This type of PCD may be implicated in neuronal loss often described at post- mortem in the brain of patients suffering from AIDS- associated neurological syndrome (Corasaniti et al. 2001a). Arachidonatemetabolites(Genis et al.1992),andinparticular prostanoids (Maccarrone et al.2000a),seemtobeinvolvedin the execution of gp120-induced PCD in the rat brain, along with an increased expression of interleukin-1b (Bagetta et al. 1999; Corasaniti et al. 2001b). However, the underlying mechanism(s) remain(s) to be elucidated. Endocannabinoids are amides, esters and ethers of long chain polyunsaturated fatty acids, found in several human tissues (Di Marzo et al. 2002). Anandamide (N-arachidonoylethanolamine, AEA) and Received November 4, 2003; revised manuscript received February 2, 2004; accepted February 6, 2004. Address correspondence and reprint requests to Prof. Mauro Mac- carrone, Department of Biomedical Sciences, University of Teramo, Piazza A. Moro 45, I-64100 Teramo, Italy. E-mail: Maccarrone@unite.it Abbreviations used: AEA, anandamide (N-arachidonoylethanol- amine); AMT, anandamide membrane transporter; BSA, bovine serum albumin; CBR, cannabinoid receptor; FAAH, fatty acid amide hydrolase; HIV-1, human immunodeficiency virus type-1; 5-LOX, 5-lipoxygenase; MAFP, methyl-arachidonoyl fluorophosphonate; NAPE, N-acyl- phosphatidylethanolamine; NArPE, N-arachidonoyl-phosphatidyletha- nolamine; PCD, programmed cell death; PLD, phospholipase D; TUNEL, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP- biotin nick end-labelling. Journal of Neurochemistry , 2004, 89, 1293–1300 doi:10.1111/j.1471-4159.2004.02430.x Ó 2004 International Society for Neurochemistry, J. Neurochem. (2004) 89, 1293–1300 1293