Utilizing primary human airway mucociliary tissue cultures to model ramifications of chronic E-cigarette usage

Electronic cigarettes are battery powered devices that use a vape-liquid to produce a vapor that is inhaled. A consequence of the rise in e-cigarette usage was the 2019 emergence of a vaping-induced respiratory disease denoted as 'e-cigarette or vaping use-associated lung injury' (EVALI). One of the suspected causes of EVALI is Vitamin E Acetate (VEA), which was found to be a diluent in certain illicit vape-pens, whereas nicotine is commonly diluted in equal parts propylene glycol and vegetable glycerin (PG:VG). The prevalent use of e-cigarettes and the emergence of a novel illness has made understanding how e-cigarette vapors affect our respiratory tissues a public health concern. We have designed and produced a simple device that can operate e-cigarettes and deliver the vapor to a chamber containing a standard cell culture multi-well plate. Here we utilize our device to model the response of human airway mucociliary tissue after chronic exposure to vapors produced from either PG:VG or VEA. We note several differences between how PG:VG and VEA vapors interact with and alter airway tissue cultures and suggest potential mechanisms for how VEA-vapors can exacerbate EVALI symptoms. Our device combined with primary human airway tissue cultures make an economical and compact model system that allows for animal-free investigations into the acute and chronic consequences of e-cigarette vapors on primary respiratory cells.

Interferon ɛ restricts Zika virus infection in the female reproductive tract

Interferon ɛ (IFNɛ) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections. Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNɛ contributes to protection against ZIKV infection in vivo is unknown. In this study, we show that IFNɛ plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNɛ was expressed not only by epithelial cells in the FRT but also by immune and stromal cells at baseline or after exposure to viruses or specific Toll-like receptor (TLR) agonists. IFNɛ-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal but not subcutaneous ZIKV infection. IFNɛ deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNɛ protected Ifnɛ-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNɛ was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNɛ in mediating protection against the transmission of ZIKV in the context of sexual contact.

Interferon ε restricts Zika virus infection in the female reproductive tract

Interferon ε (IFNε) is a unique type I IFN that has been implicated in host defense against sexually transmitted infections (STIs). Zika virus (ZIKV), an emerging pathogen, can infect the female reproductive tract (FRT) and cause devastating diseases, particularly in pregnant women. How IFNε contributes to protection against ZIKV infection in vivo is unknown. Here, we show that IFNε plays a critical role in host protection against vaginal ZIKV infection in mice. We found that IFNε was expressed not only by epithelial cells in the FRT, but also by certain immune and other cells at baseline or after exposure to viruses or specific TLR agonists. IFNε-deficient mice exhibited abnormalities in the epithelial border and underlying tissue in the cervicovaginal tract, and these defects were associated with increased susceptibility to vaginal, but not subcutaneous ZIKV infection. IFNε-deficiency resulted in an increase in magnitude, duration, and depth of ZIKV infection in the FRT. Critically, intravaginal administration of recombinant IFNε protected Ifnε-/- mice and highly susceptible Ifnar1-/- mice against vaginal ZIKV infection, indicating that IFNε was sufficient to provide protection even in the absence of signals from other type I IFNs and in an IFNAR1-independent manner. Our findings reveal a potentially critical role for IFNε in mediating protection against transmission of ZIKV in the context of sexual contact.

Human IFNe and IFNa modulate immune and anti-HIV functions through the differential involvement of IFNa receptors

Interferon e (IFNe) is a critical innate immune mediator that protects the host against sexually transmitted infections. Although the current paradigm is that IFNɛ is a type I IFN and signals through IFNa receptors (IFNARs), our and other published results show that IFNɛ has unique gene regulatory and immune functions that are distinct from IFNa. IFNɛ is constitutively expressed in the mucosa, and highly abundant in the female reproductive tract. It exhibits superior mucosal immune activity compared to IFNa/b. We have previously shown that that human IFNe induces an anti-HIV state through a mechanism independent of known type I IFN-induced HIV host restriction factors in primary macrophages. IFNɛ induces phagocytosis and reactive oxygen species that contribute to anti-HIV activity. In this study, we determined the involvement of IFNARs in immune modulation and HIV inhibition by human IFNɛ in comparison to human IFNa.

Human IFNɛ elicited a more robust immune response than human IFNa2 in PBMCs and primary macrophages. The immune profiles in response to human IFNɛ were cell-type dependent. Antibodies (Abs) against IFNAR1 or IFNAR2 blocked induction of interferon-stimulated genes (ISGs) by human IFNa2 and murine IFNe. However, anti-IFNAR2 but not anti-IFNAR1 Ab blocked human IFNe-mediated ISG induction. Interestingly, anti-IFNAR1 or anti-IFNAR2 Ab blocked cytokine induction by human IFNa2 but not by human IFNe. Finally, we found that both IFNAR1 and IFNAR2 were involved in anti-HIV activity of human IFNa2 but only IFNAR2 was involved in HIV inhibition by human IFNe. In summary, our results indicate that human IFNe, not a conventional type I IFN, modulates immune and anti-HIV functions through distinct mechanisms from IFNa2.