Anti-HIV-1 activity of elafin depends on its nuclear localization and altered innate immune activation in female genital epithelial cells

• Published in: PloS one Vol. 7; no. 12; p. e52738
• Main Authors: Drannik, Anna G, Nag, Kakon, Yao, Xiao-Dan, Henrick, Bethany M, Ball, T Blake, Plummer, Francis A, Wachihi, Charles, Kimani, Joshua, Rosenthal, Kenneth L
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27-12-2012; Public Library of Science (PLoS)
• Subjects: Acquired immune deficiency syndrome; Activation; AIDS; Antimicrobial agents; Antiviral activity; Autocrine signalling; Biology; Cell Line, Tumor; Cell Nucleus - metabolism; Cervix Uteri - cytology; DEAD Box Protein 58; DEAD-box RNA Helicases - genetics; DEAD-box RNA Helicases - metabolism; Disease Resistance; Double-stranded RNA; Elafin - physiology; Endometrium; Epithelial cells; Epithelial Cells - drug effects; Epithelial Cells - immunology; Epithelial Cells - metabolism; Epithelial Cells - virology; Female; Gene expression; Gene Expression Regulation; HIV; HIV-1 - immunology; HIV-1 - physiology; Host-Pathogen Interactions; Human immunodeficiency virus; Humans; Immune response; Immune system; Immunity, Innate; Immunology; Immunomodulation; Infections; Infectious diseases; Interleukin 8; Interleukin-8 - metabolism; Localization; Medicine; Mucosa; N-Terminus; NF-kappa B - metabolism; NF-κB protein; Nuclear transport; Paracrine signalling; Pathology; Prostitution; Proteases; Protein Structure, Tertiary; Protein Transport; Proteins; Public health; Receptors, Immunologic; Receptors, Pattern Recognition - genetics; Receptors, Pattern Recognition - metabolism; RNA; Sex industry; Sex oriented businesses; Sex Workers; Sexually transmitted diseases; Signal transduction; STD; TLR3 protein; Toll-Like Receptor 3 - genetics; Toll-Like Receptor 3 - metabolism; Toll-like receptors; Transcytosis; Translocation; Tumor Necrosis Factor-alpha; Virus Attachment; Virus Internalization; Viruses; Workers; Canada; Manitoba Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0052738

Elafin (E) and its precursor trappin-2 (Tr) are alarm antiproteases with antimicrobial and immunomodulatory activities. Tr and E (Tr/E) have been associated with HIV-1 resistance. We recently showed that Tr/E reduced IL-8 secretion and NF-κB activation in response to a mimic of viral dsRNA and contributed to anti-HIV activity of cervicovaginal lavage fluid (CVL) of HIV-resistant (HIV-R) commercial sex workers (CSWs). Additionally, Tr, and more so E, were found to inhibit attachment/entry and transcytosis of HIV-1 in human endometrial HEC-1A cells, acting through virus or cells. Given their immunomodulatory activity, we hypothesized that Tr/E could exert anti-HIV-1 activity at multiple levels. Here, using tagged and untagged Tr/E proteins, we comparatively evaluated their protease inhibitory, anti-HIV-1, and immunomodulatory activities, and cellular distribution. E appeared to function as an autocrine/paracrine factor in HEC-1A cells, and anti-HIV-1 activity of E depended on its unmodified N-terminus and altered cellular innate activation, but not its antiprotease activity. Specifically, exogenously added N-terminus-unmodified E was able to enter the nucleus and to reduce viral attachment/entry and transcytosis, preferentially affecting R5-HIV-1(ADA), but not X4-HIV-1(IIIB). Further, anti-HIV-1 activity of E was associated with significantly decreased HIV-1-triggered IL-8 release, attenuated NF-κB/p65 nuclear translocation, and significantly modulated mRNA expression of innate sensors TLR3 and RIG-I in HEC-1A cells. Most importantly, we found that elevated Tr/E in CVLs of HIV-R CSWs were associated with lower mRNA levels of TLRs 2, 3, 4 and RIG-I in the genital ECs from this cohort, suggesting a link between Tr/E, HIV-1 resistance and modulated innate viral recognition in the female genital mucosa. Collectively, our data indicate that unmodified N-terminus is critical for intranuclear localization and anti-HIV-1 activity of E. We also propose that E-mediated altered cellular innate activation most likely contributes to the HIV-R phenotype of these subjects.