P40.30
Background: Understanding the mechanisms underlying mucosal susceptibility to HIV infection and defining new biomarkers of vaginal inflammation and immune activation are essential to developing safe and effective HIV prevention products. To this end we analyzed transcriptomes of human vaginal tissues after in vivo treatment with pro-inflammatory (PIC) and non-inflammatory (NIC) compounds.
Methods: Nineteen women (mean age=32) applied 2-4 doses of PICs, including imiquimod and nonoxynol-9 (N9), and NIC, hydroxyethyl cellulose (HEC)-based placebo gel, intravaginally, in a crossover design. Vaginal biopsies were taken at baseline and after treatment and preserved in RNAlater or formalin. Gene expression (n=93 tissue samples) was analyzed by using Affymetrix U133 Plus 2 arrays. Data processing was done using BRB-array tools software. Genes showing statistically different expression (p<0.001) between treatment and control groups and fold change differences≥2 were considered differentially expressed. Functional analysis was done using Ingenuity Pathway Analysis and published data. Immunohistochemical analysis (IHC) was performed on paraffin embedded vaginal tissues.
Results: Transcriptomic analysis indicated that HEC did not alter mucosal gene expression significantly. Conversely, imiquimod caused dysregulation of 879 genes, and N9 of 89 genes. There were 66 genes common to both PIC treatments. Functional analysis indicated 27 genes involved in inflammatory and immune responses, 8 of which were chemoattractants for immune cells. Upstream regulation analysis revealed strong interferon signature. IHC showed PIC-induced influx of immune cells, including CD3+ T cells, into the vaginal mucosa.
Conclusions: Intravaginal application of PICs induced a strong mucosal immuno-inflammatory response and transcriptomic change with a common profile of dysregulated genes which can serve as biomarkers of vaginal inflammation and immune activation in the safety evaluation of HIV prevention interventions.
