P40.04
Background: The HIV prevention field requires better tools for studying mucosal drug toxicity and general inflammation. Standard tools that study individual components in isolation likely underestimates the global effects that may underpin complex immunological processes. Advances in mass spectrometry allow for the measurement of a large number of immunological parameters simultaneously. Here we evaluate the utility of this technology for examining rectal mucosal samples, and the effect of the known mucosal irritant nonoxynol-9 on the host rectal mucosal proteome.
Methods: Rectal sponge samples were collected from 7 individuals pre (Visit 1) and after 7 consecutive days (Visit 3) of once-daily doses of Nonoxynol-9 (N9) or placebo HEC gel controls (MTN-007 phase 1 clinical trial). Sponge eluates were analyzed by tandem mass spectrometry.
Results: 488 unique proteins were identified, that covered many functions that may be important for product toxicity including dermatitis (57, 6.78E-29), skin development (23, 4.57E-18), allergic response (47, p=3.0E-20), psoriasis (127, p=5.67E-38), cell death (127, 3.68E-16), necrosis (107, 4.82E-13), and cancer (279, 1.1E-10). 46 proteins were differentially expressed (p<0.05) between N9 and HEC controls, after 7 days of exposure (V3) (filtered to non-treated controls (n=8, p<0.05). Hierarchical clustering showed a general overexpression of proteins in the N9 treatment arm. Biofunctional analysis indicated these factors belong to skin disorders (20) and general inflammation (11), and apoptotic, carcinogenic, and pro-inflammatory canonical pathways, indicating a wide range of inflammatory and toxic effects of N9 (p<0.05, BH corrected).
Conclusions: This indicates that proteomics methods are suitable for monitoring immune factors in rectal mucosa, and mucosal-irritant associated responses. This shows the utility of systems biology techniques and adds to the available toolsets for toxicity monitoring of future microbicide candidates.
