Enhancing Interferon Regulatory Factor 7 Mediated Antiviral Responses and Decreasing Nuclear Factor Kappa B Expression Limit HIV-1 Replication in Cervical Tissues

Establishment of a productive HIV-1 infection in the female reproductive tract likely depends on the balance between anti-viral and pro-inflammatory responses leading to activation and proliferation of HIV target cells. Immune modulators that boost anti-viral and depress pro-inflammatory immune responses may decrease HIV-1 infection or replication. Polyinosinic: polycytidylic [Poly (I:C)] has been reported to down-regulate HIV-1 replication in immune cell subsets and lymphoid tissues, yet the scope and mechanisms of poly (I:C) regulation of HIV-1 replication in the cervicovaginal mucosa, the main portal of viral entry in women remain unknown. Using a relevant, underexplored ex vivo cervical tissue model, we demonstrated that poly (I:C) enhanced Interferon Regulatory Factor (IRF)7 mediated antiviral responses and decreased tissue Nuclear Factor Kappa B (NF κ B) RNA expression. This pattern of cellular transcription factor expression correlated with decreased HIV-1 transcription and viral release. Reducing IRF7 expression up-regulated HIV-1 and NFκB transcription, providing proof of concept for the critical involvement of IRF7 in cervical tissues. By combining poly (I:C) with a suboptimal concentration of tenofovir, the leading anti-HIV pro-phylactic microbicide candidate, we demonstrated an earlier and greater decrease in HIV replication in poly (I:C)/tenofovir treated tissues compared with tissues treated with tenofovir alone, indicating overall improved efficacy. Poly (I:C) decreases HIV-1 replication by stimulating IRF7 mediated antiviral responses while reducing NFκB expression. Early during the infection, poly (I:C) improved the anti-HIV-1 activity of suboptimal concentrations of tenofovir likely to be present during periods of poor adherence i.e. inconsistent or inadequate drug use. Understanding interactions between anti-viral and pro-inflammatory immune responses in the genital mucosa will provide crucial insights for the identification of targets that can be harnessed to develop preventative combination strategies to improve the efficacy of topical or systemic antiviral prophylactic agents and protect women from HIV-1 and other sexually transmitted infections

Differences in gene expression and cytokine production by crystalline vs. amorphous silica in human lung epithelial cells

<p>Abstract</p> <p>Background</p> <p>Exposure to respirable crystalline silica particles, as opposed to amorphous silica, is associated with lung inflammation, pulmonary fibrosis (silicosis), and potentially with lung cancer. We used Affymetrix/GeneSifter microarray analysis to determine whether gene expression profiles differed in a human bronchial epithelial cell line (BEAS 2B) exposed to cristobalite vs. amorphous silica particles at non-toxic and equal surface areas (75 and 150 × 10⁶μm²/cm²). Bio-Plex analysis was also used to determine profiles of secreted cytokines and chemokines in response to both particles. Finally, primary human bronchial epithelial cells (NHBE) were used to comparatively assess silica particle-induced alterations in gene expression.</p> <p>Results</p> <p>Microarray analysis at 24 hours in BEAS 2B revealed 333 and 631 significant alterations in gene expression induced by cristobalite at low (75) and high (150 × 10⁶μm²/cm²) amounts, respectively (p < 0.05/cut off ≥ 2.0-fold change). Exposure to amorphous silica micro-particles at high amounts (150 × 10⁶μm²/cm²) induced 108 significant gene changes. Bio-Plex analysis of 27 human cytokines and chemokines revealed 9 secreted mediators (p < 0.05) induced by crystalline silica, but none were induced by amorphous silica. QRT-PCR revealed that cristobalite selectively up-regulated stress-related genes and cytokines (<it>FOS, ATF3, IL6 </it>and <it>IL8</it>) early and over time (2, 4, 8, and 24 h). Patterns of gene expression in NHBE cells were similar overall to BEAS 2B cells. At 75 × 10⁶μm²/cm², there were 339 significant alterations in gene expression induced by cristobalite and 42 by amorphous silica. Comparison of genes in response to cristobalite (75 × 10⁶μm²/cm²) revealed 60 common, significant gene alterations in NHBE and BEAS 2B cells.</p> <p>Conclusions</p> <p>Cristobalite silica, as compared to synthetic amorphous silica particles at equal surface area concentrations, had comparable effects on the viability of human bronchial epithelial cells. However, effects on gene expression, as well as secretion of cytokines and chemokines, drastically differed, as the crystalline silica induced more intense responses. Our studies indicate that toxicological testing of particulates by surveying viability and/or metabolic activity is insufficient to predict their pathogenicity. Moreover, they show that acute responses of the lung epithelium, including up-regulation of genes linked to inflammation, oxidative stress, and proliferation, as well as secretion of inflammatory and proliferative mediators, can be indicative of pathologic potential using either immortalized lines (BEAS 2B) or primary cells (NHBE). Assessment of the degree and magnitude of these responses <it>in vitro </it>are suggested as predictive in determining the pathogenicity of potentially harmful particulates.</p

Mechanisms of oxidative stress and alterations in gene expression by Libby six-mix in human mesothelial cells

<p>Abstract</p> <p>Background</p> <p>Exposures to an amphibole fiber in Libby, Montana cause increases in malignant mesothelioma (MM), a tumor of the pleural and peritoneal cavities with a poor prognosis. Affymetrix microarray/GeneSifter analysis was used to determine alterations in gene expression of a human mesothelial cell line (LP9/TERT-1) by a non-toxic concentration (15×10⁶μm²/cm²) of unprocessed Libby six-mix and negative (glass beads) and positive (crocidolite asbestos) controls. Because manganese superoxide dismutase (MnSOD; SOD2) was the only gene upregulated significantly (p < 0.05) at both 8 and 24 h, we measured SOD protein and activity, oxidative stress and glutathione (GSH) levels to better understand oxidative events after exposure to non-toxic (15×10⁶μm²/cm²) and toxic concentrations (75×10⁶μm²/cm²) of Libby six-mix.</p> <p>Results</p> <p>Exposure to 15×10⁶μm²/cm²Libby six-mix elicited significant (p < 0.05) upregulation of one gene (<it>SOD2</it>; 4-fold) at 8 h and 111 gene changes at 24 h, including a 5-fold increase in <it>SOD2</it>. Increased levels of SOD2 mRNA at 24 h were also confirmed in HKNM-2 normal human pleural mesothelial cells by qRT-PCR. SOD2 protein levels were increased at toxic concentrations (75×10⁶μm²/cm²) of Libby six-mix at 24 h. In addition, levels of copper-zinc superoxide dismutase (Cu/ZnSOD; SOD1) protein were increased at 24 h in all mineral groups. A dose-related increase in SOD2 activity was observed, although total SOD activity remained unchanged. Dichlorodihydrofluorescein diacetate (DCFDA) fluorescence staining and flow cytometry revealed a dose- and time-dependent increase in reactive oxygen species (ROS) production by LP9/TERT-1 cells exposed to Libby six-mix. Both Libby six-mix and crocidolite asbestos at 75×10⁶μm²/cm²caused transient decreases (p < 0.05) in GSH for up to 24 h and increases in gene expression of heme oxygenase 1 (<it>HO-1</it>) in LP9/TERT-1 and HKNM-2 cells.</p> <p>Conclusions</p> <p>Libby six-mix causes multiple gene expression changes in LP9/TERT-1 human mesothelial cells, as well as increases in SOD2, increased production of oxidants, and transient decreases in intracellular GSH. These events are not observed at equal surface area concentrations of nontoxic glass beads. Results support a mechanistic basis for the importance of SOD2 in proliferation and apoptosis of mesothelial cells and its potential use as a biomarker of early responses to mesotheliomagenic minerals.</p

Enhancing Interferon Regulatory Factor 7 Mediated Antiviral Responses and Decreasing Nuclear Factor Kappa B Expression Limit HIV-1 Replication in Cervical Tissues.

Establishment of a productive HIV-1 infection in the female reproductive tract likely depends on the balance between anti-viral and pro-inflammatory responses leading to activation and proliferation of HIV target cells. Immune modulators that boost anti-viral and depress pro-inflammatory immune responses may decrease HIV-1 infection or replication. Polyinosinic:polycytidylic [Poly (I:C)] has been reported to down-regulate HIV-1 replication in immune cell subsets and lymphoid tissues, yet the scope and mechanisms of poly (I:C) regulation of HIV-1 replication in the cervicovaginal mucosa, the main portal of viral entry in women remain unknown. Using a relevant, underexplored ex vivo cervical tissue model, we demonstrated that poly (I:C) enhanced Interferon Regulatory Factor (IRF)7 mediated antiviral responses and decreased tissue Nuclear Factor Kappa B (NFκB) RNA expression. This pattern of cellular transcription factor expression correlated with decreased HIV-1 transcription and viral release. Reducing IRF7 expression up-regulated HIV-1 and NFκB transcription, providing proof of concept for the critical involvement of IRF7 in cervical tissues. By combining poly (I:C) with a suboptimal concentration of tenofovir, the leading anti-HIV prophylactic microbicide candidate, we demonstrated an earlier and greater decrease in HIV replication in poly (I:C)/tenofovir treated tissues compared with tissues treated with tenofovir alone, indicating overall improved efficacy. Poly (I:C) decreases HIV-1 replication by stimulating IRF7 mediated antiviral responses while reducing NFκB expression. Early during the infection, poly (I:C) improved the anti-HIV-1 activity of suboptimal concentrations of tenofovir likely to be present during periods of poor adherence i.e. inconsistent or inadequate drug use. Understanding interactions between anti-viral and pro-inflammatory immune responses in the genital mucosa will provide crucial insights for the identification of targets that can be harnessed to develop preventative combination strategies to improve the efficacy of topical or systemic antiviral prophylactic agents and protect women from HIV-1 and other sexually transmitted infections

Poly (I:C) decreases HIV-1 replication in PBMCs.

<p>HIV-1 p24 levels (ng/ml) in HIV-1 infected PBMCs left untreated or treated with poly (I:C) at 20 μg/ml were measured after washing the residual input virus (day 0), and again on days 3, 5 and 7 after infection. Results are shown as the mean ± STDEV from three experiments with each condition tested in triplicate. * p = 0.008, p = 0.01 and p = 0.009 for days 3, 5 and 7 after infection between untreated and poly (I:C) treated PBMCs.</p

Decreasing IRF7 expression enhances HIV-1 and RelA transcription.

<p>(A) IRF7, (C and F) HIV-1, (B, D and G) IFNα and (E and H) RelA transcription in HIV-1-infected cervical tissues treated with random and IRF7 targeting siRNA were quantified by RT-PCR before (A) and (B) and on days 1 (C, D and E) and 3 (F, G and H) after HIV-1 infection. All data was normalized to GAPDH. Results were consistent among four donors and are shown as the mean ± STDEV from one representative experiment with each condition tested in triplicate. * p<0.05 for tissues treated with random and IRF7 targeting siRNA.</p

Poly (I:C) decreases HIV-1 replication in cervical tissues.

<p>(A) HIV-1 p24 levels (ng/ml) in HIV-1 infected cervical tissues left untreated or treated with poly (I:C) at 20 μg/ml were measured after washing the residual input virus (day 0), and again on days 11 and 21 after infection. Results are shown as the geometric mean ± STDEV from triplicate values of 12 individual donors. *p = 0.00005 and p = 0.07 between untreated and poly (I:C) treated tissues at days 11 and 21 after infection, respectively. (B) Levels of HIV-1 reverse transcription and (C) integration in donor matched HIV-1 infected cervical tissues left untreated or treated with poly (I:C) at 20 μg/ml were quantified by RT-PCR on days 11 and 21 after infection. All data was normalized to human β actin. For HIV-1 reverse transcription and integration, day 11 values in untreated control tissues were set to 1. Day 11 values in poly (I:C) treated tissues or days 21 values in untreated or poly (I:C) treated tissues were normalized to 1. Results are shown as the relative geometric mean ± STDEV from triplicate values of 8 and 12 individual donors on days 11 and day 21 respectively. *p = 0.004 and p = 0.0009 between untreated and poly (I:C) treated tissues at days 11 and 21 after infection, respectively.</p

Poly (I:C) improves the efficacy of TFV in cervical tissues.

<p>(A) HIV-1 p24 levels (ng/ml) in HIV-1 infected cervical tissues left untreated or treated with TFV at 10 μg/ml alone or in combination with poly (I:C) at 20 μg/ml were evaluated after washing the residual input virus (day 0), and again on days 11 and 21 after infection. (B) Levels of HIV-1 reverse transcription and (C) viral integration in donor matched HIV-1 infected cervical tissues left untreated or treated with TFV at 10 μg/ml alone or in combination poly (I:C) at 20 μg/ml were quantified by RT-PCR on days 11 and 21 after infection. All data was normalized to human β-actin. For HIV-1 reverse transcription and integration, day 11 values in untreated control tissues were set to 1. Day 11 values in TFV or TFV/Poly (I:C) treated tissues or days 21 values in untreated; TFV or TFV/Poly (I:C) treated tissues were normalized to 1. Results were consistent among 4 donors and are shown as the mean ± STDEV from one representative experiment with each condition tested in triplicate. * p<0.05 for untreated, poly (I:C) and TFV treated tissues. (D) FACS analysis of single cell suspensions from HIV-1 infected ectocervical tissues left untreated or treated with TFV at 10 μg/ml and stained for CD3 and CD8 on day 11 after infection. CD4⁺ T cells were defined as CD3⁺ and CD8^-. For each panel the percentage of CD4⁺ T cells from the total cell number is depicted in the upper left corner. Results were consistent among 4 donors.</p

Poly (I:C) decreases HIV-1 transcription in cervical tissues by enhancing IRF7 mediated antiviral responses and reducing RelA expression.

<p>(A) Levels of HIV-1, (B) RelA, (C) IRF7, (D) IRF3, (E) RIG-1, (F) TLR3, (G) IFNα and (H) IFNβ transcription in HIV-1-infected cervical tissues left untreated or treated with poly (I:C) at 20 μg/ml were quantified by RT-PCR on days 3 and 5 after infection. All data was normalized to glyceraldehyde 3-phophate (GAPDH). For each gene, day 3 values in untreated control tissues were set to 1. Day 5 values in untreated control tissues or days 3 and 5 values in poly (I:C) treated tissues were normalized to 1. Results were consistent among three donors and are shown as the mean ± STDEV from one representative experiment with each condition tested in triplicate. * p<0.05 for untreated and poly (I:C) treated tissues.</p

Poly (I:C) decreases HIV-1 transcription by increasing IRF7 expression in PBMCs.

<p>(A) Levels of HIV-1, (B) RelA, (C) IRF7, (D) IRF3, (E) RIG-1, and (F) TLR3 transcription in HIV-1 infected PBMCs left untreated or treated with poly (I:C) at 20 μg/ml were quantified by RT-PCR on days 3 and 5 after infection. All data was normalized to GAPDH. For each gene, day 3 values in untreated control tissues were set to 1. Day 5 values in untreated control tissues or days 3 and 5 values in poly (I:C) treated tissues were normalized to 1. Results were consistent among three donors and are shown as the mean ± STDEV from one representative experiments with each condition tested in triplicate. * p<0.05 for untreated and poly (I:C) treated cells.</p