HIV induction of beta defensins in oral epithelial cells

We previously showed that HIV-1 induces expression of hBD-2 and -3 significantly above baseline in normal human oral epithelial cells (NHOEC) and that these peptides inhibit HIV replication in vitro (Quinones-Mateu et al, 2003). Objective: To initiate characterization of the mechanism(s) of activation of hBD-2 and -3 by HIV-1 in NHOECs. Methods: Time course analysis of hBD-2 and -3 expression were conducted by challenging mixed donor NHOEC monolayers with primary and laboratory adapted HIV-1 strains representing both viral bio-phenotypes (X4 and R5), for up to 72 hours. Monolayers were also challenged with either (i) recombinant HIV-1 monomeric gp120, (ii) trimeric gp140, or (iii) virally regulated human immunodeficiency virus-like particles that express X4 and R5 envelopes and are deficient in activities associated with viral reverse transcriptase and protease (VLP). All analyses used real time PCR to determine hBD transcript expression, respectively. Results: Unlike gp120 and gp140, VLPs induced the expression of hBD-2 and -3 mRNA 5- to 30-fold above baseline after 48 hours of exposure to VLP89.6 (X4R5) and VLPADA (R5) (10ng/ml). The time course study showed that HIV induced hBD2 mRNA expression after 18 hours of exposure, reaching the highest level after 48 hours. In contrast, hBD3 mRNA was induced after only a 3 hr challenge. Conclusions: The time course results indicate that hBD2 and -3 are upregulated by HIV via different pathways. Interestingly, the induction of hBD-2 and -3 mRNA after incubation of NHOECs with VLPs was comparable to that observed with actual virions. Elucidation of the viral hBD inducing components as well as the different hBD induction pathways are underway. Supported by NIH/NIDCR 1RO1 DE-015510