IFI16 and cGAS cooperate in the activation of STING during DNA sensing in human keratinocytes

Many human cells can sense the presence of exogenous DNA during infection though the cytosolic DNA receptor cyclic GMP-AMP synthase (cGAS), which produces the second messenger cyclic GMP-AMP (cGAMP). Other putative DNA receptors have been described, but whether their functions are redundant, tissue-specific or integrated in the cGAS-cGAMP pathway is unclear. Here we show that interferon-γ inducible protein 16 (IFI16) cooperates with cGAS during DNA sensing in human keratinocytes, as both cGAS and IFI16 are required for the full activation of an innate immune response to exogenous DNA and DNA viruses. IFI16 is also required for the cGAMP-induced activation of STING, and interacts with STING to promote STING phosphorylation and translocation. We propose that the two DNA sensors IFI16 and cGAS cooperate to prevent the spurious activation of the type I interferon response

Glucocortiocoid Treatment of MCMV Infected Newborn Mice Attenuates CNS Inflammation and Limits Deficits in Cerebellar Development

Infection of the developing fetus with human cytomegalovirus (HCMV) is a major cause of central nervous system disease in infants and children; however, mechanism(s) of disease associated with this intrauterine infection remain poorly understood. Utilizing a mouse model of HCMV infection of the developing CNS, we have shown that peripheral inoculation of newborn mice with murine CMV (MCMV) results in CNS infection and developmental abnormalities that recapitulate key features of the human infection. In this model, animals exhibit decreased granule neuron precursor cell (GNPC) proliferation and altered morphogenesis of the cerebellar cortex. Deficits in cerebellar cortical development are symmetric and global even though infection of the CNS results in a non-necrotizing encephalitis characterized by widely scattered foci of virus-infected cells with mononuclear cell infiltrates. These findings suggested that inflammation induced by MCMV infection could underlie deficits in CNS development. We investigated the contribution of host inflammatory responses to abnormal cerebellar development by modulating inflammatory responses in infected mice with glucocorticoids. Treatment of infected animals with glucocorticoids decreased activation of CNS mononuclear cells and expression of inflammatory cytokines (TNF-α, IFN-β and IFNγ) in the CNS while minimally impacting CNS virus replication. Glucocorticoid treatment also limited morphogenic abnormalities and normalized the expression of developmentally regulated genes within the cerebellum. Importantly, GNPC proliferation deficits were normalized in MCMV infected mice following glucocorticoid treatment. Our findings argue that host inflammatory responses to MCMV infection contribute to deficits in CNS development in MCMV infected mice and suggest that similar mechanisms of disease could be responsible for the abnormal CNS development in human infants infected in-utero with HCMV

Case Reports: Chemokine and Cytokine Profiling in Patients with Herpetic Uveitis

Nam V Nguyen,1,2,* Susanne L Linderman,3,* Tolulope Fashina,1,* Max Devine,1,2 Christopher D Conrady,1,4 Jessica G Shantha,5,6 Rafi Ahmed,3,* Steven Yeh1,6,* 1Department of Ophthalmology, University of Nebraska Medical Center, Omaha, NE, USA; 2College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA; 3Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, USA; 4Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA; 5Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA; 6Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA*These authors contributed equally to this workCorrespondence: Steven Yeh, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA, Tel +1 402 559-2020, Email [email protected]: To report cytokine/chemokine profiles of ocular fluid in two patients with herpetic uveitis.Methods: Cytokine and chemokine profiling of ocular fluid was performed in two patients with herpetic uveitis. Ocular fluid findings were correlated with disease manifestations and the patients’ clinical course.Observation: Case 1 was a 45-year-old female, who was evaluated for an 11-day history of recurrent redness, and decreased vision in the right eye (OD) and was diagnosed with acute retinal necrosis. Ocular fluid from anterior chamber paracentesis was positive for varicella zoster virus (VZV) via PCR testing. Subsequently, the patient developed proliferative vitreoretinopathy requiring a pars plana vitrectomy. Ocular fluid sample cytokine/chemokine analysis detected IFN-γ, TNF-α, IL-8, IL-18, MIP-1β, IP-10, and MCP-1 with MCP-1 being the most abundant cytokine. Case 2 was a 30-year-old female with a two-month history of progressive pain and decreased vision OD. She was diagnosed with hypertensive anterior uveitis after diagnostic anterior chamber paracentesis. Despite successful therapy for the anterior uveitis, her intraocular pressure remained elevated and required a glaucoma filtration procedure. Ocular fluid sample was collected at the time of surgery for cytokine/chemokine profiles analysis, and levels of 7 cytokines/chemokines were detected including IL-6, IL-8, IL-18, MIP-1β, IP-10, MCP-1, and IL-1RA with IL-1RA being the most abundant cytokine.Conclusion: Cytokine/chemokine profiles of two patients with herpetic uveitis showed elevated levels of MCP-1, IP-10, IL-8, and IL-18 while IL-1RA was elevated in the chronic phase of hypertensive anterior uveitis. Further studies of cytokines and chemokines will improve our understanding of soluble mediators and potential targets for herpetic uveitis.Keywords: case reports, cytokine, chemokine, acute retinal necrosis, anterior hypertensive uveiti

Type I Interferon and NF-κB Activation Elicited by Herpes Simplex Virus gH/gL via αvβ3 Integrin in Epithelial and Neuronal Cell Lines

αvβ3 integrin represents a novel sensing system which detects herpes simplex virus (HSV) and bacterial constituents. In cooperation with Toll-like receptor 2 (TLR2), it elicits an innate response that leads to activation of type I interferon (IFN), NF-κB, and a specific set of cytokines. We report that this defensive branch is functional in cells which represent experimental models of epithelial, including keratinocytic, and neuronal cells. These are the major targets of HSV in vivo. HSV entered the three cell lines via distinct routes. Hence, the defensive response was independent of the route of virus entry. Soluble gH/gL sufficed to elicit type I IFN and NF-κB activation and represents the viral pathogen-associated molecular pattern (PAMP) of this defense system