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

PLoS One. 2012;7(12):e52738. doi: 10.1371/journal.pone.0052738. Epub 2012 Dec 27.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 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
  • Elafin / physiology*
  • Epithelial Cells / drug effects*
  • Epithelial Cells / immunology
  • Epithelial Cells / metabolism
  • Epithelial Cells / virology
  • Female
  • Gene Expression Regulation
  • HIV-1 / immunology
  • HIV-1 / physiology*
  • Host-Pathogen Interactions
  • Humans
  • Immunity, Innate*
  • Interleukin-8 / metabolism
  • NF-kappa B / metabolism
  • Protein Structure, Tertiary
  • Protein Transport
  • Receptors, Immunologic
  • Receptors, Pattern Recognition / genetics
  • Receptors, Pattern Recognition / metabolism
  • Sex Workers
  • Toll-Like Receptor 3 / genetics
  • Toll-Like Receptor 3 / metabolism
  • Transcytosis
  • Tumor Necrosis Factor-alpha
  • Virus Attachment
  • Virus Internalization

Substances

  • Elafin
  • Interleukin-8
  • NF-kappa B
  • PI3 protein, human
  • Receptors, Immunologic
  • Receptors, Pattern Recognition
  • TLR3 protein, human
  • Toll-Like Receptor 3
  • Tumor Necrosis Factor-alpha
  • RIGI protein, human
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases

Grants and funding

This research was supported by a grant as part of the Comprehensive T Cell Vaccine Immune Monitoring Consortium (CTC-VIMC), a key component of the Collaboration for AIDS Vaccine Development (CAVD) funded by the Bill and Melinda Gates Foundation to K.L.R. A.G.D. was supported, in part, by a Studentship Award from the Ontario HIV Treatment Network (OHTN) and K.L.R. by a Career Scientist Award from the OHTN. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.