Immune Dysregulation in Patients Persistently Infected with Human Papillomaviruses 6 and 11

Human Papillomaviruses (HPVs) 6 and 11 are part of a large family of small DNA viruses, some of which are commensal. Although much of the population can contain or clear infection with these viruses, there is a subset of individuals who develop persistent infection that can cause significant morbidity and on occasion mortality. Depending on the site of infection, patients chronically infected with these viruses develop either recurrent, and on occasion, severe genital warts or recurrent respiratory papillomas that can obstruct the upper airway. The HPV-induced diseases described are likely the result of a complex and localized immune suppressive milieu that is characteristic of patients with persistent HPV infection. We review data that documents impaired Langerhans cell responses and maturation, describes the polarized adaptive T-cell immune responses made to these viruses, and the expression of class select II MHC and KIR genes that associate with severe HPV6 and 11 induced disease. Finally, we review evidence that documents the polarization of functional TH2 and T-regulatory T-cells in tissues persistently infected with HPV6 and 11, and we review evidence that there is suppression of natural killer cell function. Together, these altered innate and adaptive immune responses contribute to the cellular and humoral microenvironment that supports HPV 6 and 11-induced disease

Poly(I:C) induces controlled release of IL-36gamma from keratinocytes in the absence of cell death

The epithelium is part of an integrated immune system where cytokines, toll-like receptors and their ligands, and extracellular vesicles play a crucial role in initiating an innate immune response. IL-36gamma is a pro-inflammatory member of the IL-1 family that is mainly expressed by epithelial cells, but regulation of its expression and release are only beginning to be understood. Previous studies reported that IL-36gamma is abundant in recurrent respiratory papillomatosis, a rare but devastating disease caused by human papillomaviruses (HPV) types 6 and 11, in which papillomas recurrently grow in and block the airway. Despite the overexpression of IL-36gamma, papilloma tissues show no evidence of inflammation, possibly due to suppression of its release by HPVs. We have used primary human foreskin keratinocytes as a model to study IL-36gamma regulation in normal epithelial cells. Low doses of poly(I:C) mediate expression and release of IL-36gamma without inducing the cell death reported by those using high doses. PKR, an enzyme required for inflammasome activation, does not contribute to controlled release of IL36gamma. The keratinocytes secrete IL-36gamma in two forms, soluble and in extracellular vesicles. We conclude that there are two separately regulated pathways for the controlled secretion of IL-36gamma from keratinocytes, which could contribute to the modulation of both local and systemic immune responses to viruses and other pathogens

TOR and PKA Pathways Synergize at the Level of the Ste11 Transcription Factor to Prevent Mating and Meiosis in Fission Yeast

[Background]: In the fission yeast Schizosaccharomyces pombe, the TOR (target of rapamycin) and PKA (protein kinase A) signaling transduction pathways regulate the expression of genes required for cell growth and sexual differentiation in response to the nutritional environment. Inhibition of Tor2 signaling results in the induction of genes involved in sexual differentiation, and the cells undergo mating and meiosis, even under good nutritional conditions. The same phenotype is observed in mutants in which the PKA pathway is inactive. By contrast, Tor2 overexpression or mutations that hyperactivate PKA signaling impair sexual differentiation, even under poor nutritional conditions. Accordingly, a very important question is to understand the molecular mechanism by which these two pathways coordinately regulate gene expression in response to nutrients. [Methodology/Principal Findings]: Here we demonstrate that TOR and PKA pathways operate coordinately to negatively regulate sexual differentiation by inhibiting the nuclear accumulation of the Ste11 transcription factor. However, the Tor2 pathway is unable to block the nuclear localization of Ste11 under good nutritional conditions when the PKA pathway is inactive. Using microarray analyses, we found that both pathways inhibit sexual differentiation by blocking ste11-dependent gene expression. [Conclusions/Significance]: We conclude that both the PKA and the TOR pathways inhibit Ste11 nuclear accumulation to repress Ste11-dependent gene expression. However, the PKA pathway plays a quantitatively more important role than the TOR pathway in this process.N.V. is supported by a postdoctoral grant from the Carlos III Institute, Ministerio de Sanidad. Our group is supported by grants from la Junta de Castilla y Leon (Grupo de Excelencia grant GR265) and the Spanish Ministry of Science and Innovation (BFU2008-01808 and Consolider Ingenio CSD2007-00015).Peer reviewe

Alternate Splicing of Interleukin-1 Receptor Type II (IL1R2) In Vitro Correlates with Clinical Glucocorticoid Responsiveness in Patients with AIED

Autoimmune Inner Ear Disease (AIED) is poorly characterized clinically, with no definitive laboratory test. All patients suspected of having AIED are given glucocorticoids during periods of acute hearing loss, however, only half initially respond, and still fewer respond over time

Extracellular vesicles produced by primary human keratinocytes in response to TLR agonists induce stimulus-specific responses in antigen-presenting cells.

Cells can communicate through the extracellular vesicles (EVs) they secrete. Pathogen associated molecular patterns (PAMPs), alter the biophysical and communicative properties of EVs released from cells, but the functional consequences of these changes are unknown. Characterization of keratinocyte-derived EVs after poly(I:C) treatment (poly(I:C)-EVs) showed slight differences in levels of EV markers TSG101 and Alix, a loss of CD63 and were positive for autophagosome marker LC3b-II and the cytokine IL36γ compared to EVs from unstimulated keratinocytes (control-EVs). Flagellin treatment (flagellin-EVs) led to an EV marker profile like control-EVs but lacked LC3b-II. Flagellin-EVs also lacked IL-36γ despite nearly identical intracellular levels. While poly(I:C) treatment led to the clear emergence of a > 200 nm diameter EV sub-population, these were not found in flagellin-EVs. EV associated IL-36γ colocalized with LC3b-II in density gradient analysis, equilibrating to 1.10 g/mL, indicating a common EV species. Poly(I:C), but not flagellin, induced intracellular vesicles positive for IL-36γ, LC3b-II, Alix and TSG101, consistent with fusion of autophagosomes and multivesicular bodies. Simultaneous rapamycin and flagellin treatment induced similar intracellular vesicles but was insufficient for the release of IL-36γ+/LC3b-II+ EVs. Finally, a qRT-PCR array screen showed eight cytokine/chemokine transcripts were altered (p < 0.05) in monocyte-derived Langerhans cells (LCs) when stimulated with poly(I:C)-EVs while three were altered when LCs were stimulated with flagellin-EVs compared to control-EVs. After independent confirmation, poly(I:C)-EVs upregulated BMP6 (p = 0.035) and flagellin-EVs upregulated CXCL8 (p = 0.005), VEGFA (p = 0.018) and PTGS2 (p = 0.020) compared to control-EVs. We conclude that exogenous signals derived from pathogens can alter keratinocyte-mediated modulation of the local immune responses by inducing changes in the types of EVs secreted and responses in antigen presenting cells