Orphan opioid receptor oligonucleotides inhibit HIV-1 expression in human brain cells

We found that orphan opioid receptor (OR) mRNA was constitutively expressed in human fetal microglia, astrocytes, and cerebral cortical neurons. An OR antisense oligonucleotide markedly inhibited HIV-1 expression in enriched microglial cell and the mixed glial/neuronal cell cultures but not in the chronically infected promonocytic U1 cells. The sense oligonucleotide also inhibited HIV-1 expression in brain cell cultures. These findings indicate that while human brain cells constitutively express mRNA for OR, antisense oligonucleotides to OR non-specifically inhibit acute HIV- 1 infection.