Biology subjects

Dozmorov, I.

Publications and source records attributed to Dozmorov, I..

3 recordsLinked to original sources

bioRxiv2021

WY14643 Increases Herpesvirus Replication Independent of PPARα Expression and Inhibits IFNβ Production

Peroxisome proliferator activated receptor (PPAR) agonists are commonly used to treat metabolic disorders in humans because they regulate fatty acid oxidation and cholesterol metabolism. In addition to their roles in controlling metabolism, PPAR agonists also regulate inflammation and are immunosuppressive in models of autoimmunity. We aimed to test whether activation of PPAR with clinically relevant ligands could impact herpesvirus infection using the model strain murine gammaherpesvirus-68. We found that PPAR agonists WY14643 and fenofibrate increased herpesvirus replication in vitro. In vivo, WY14643 increased viral replication and caused lethality in mice. Unexpectedly, these effects proved independent of PPAR. Investigating the mechanism of action for WY14643, we found that it suppresses production of type I interferon by inhibiting stimulator of interferon (STING), which lies downstream of the cytoplasmic DNA sensor cGAS. Thus, WY14643 regulates interferon downstream of cytoplasmic DNA recognition and increases herpesvirus replication in a PPAR-independent manner. Taken together, our data indicate that caution should be employed when using PPAR agonists in immuno-metabolic studies, as they can have off-target effects on viral replication. ImportancePPAR agonists are used clinically to treat both metabolic and inflammatory disorders. Because viruses are known to rewire host metabolism to their own benefit, the intersection of immunity, metabolism, and virology is an important research area. Our article is an important contribution to this field because for two reasons. First, it shows a role for PPAR agonists in altering virus detection by cells. Second, it shows that PPAR agonists can affect virus replication in a manner unrelated to their expected genetic function. This knowledge is valuable for anyone seeking to use PPAR agonists as a research tool.

immunology↗

bioRxiv2019

Metabolic Control of Viral Infection through PPAR-α Regulation of STING Signaling

Peroxisomal proliferator activated receptors (PPARs) are sensors of dietary lipids and pharmacological targets in the treatment of metabolic disorders. PPAR ligands are also immunosuppressive. However, their function during infection is debated and the mechanisms that underlie their immunoregulatory properties are unclear. We investigated the consequences of PPAR activation during herpesvirus infection. We found that activation of PPAR- increased herpesvirus replication, suppressed type I interferon production and induced reactive oxygen species (ROS). We discovered that ROS induced by PPAR- stimulation suppressed the cytoplasmic DNA sensing pathway after direct activation of stimulator of interferon (STING), the ER adapter downstream of cytoplasmic DNA recognition. Although high ROS induces inflammasome activation and cytokine production, we found that ROS inhibited interferon production after cytoplasmic DNA recognition. Treatment of mice with a clinically relevant agonist of PPAR- increased herpesvirus replication and pathogenesis, comparable to levels observed previously in type I interferon receptor knockout mice. These findings reveal that activation of PPAR- regulates immunity to cytoplasmic DNA and DNA virus infection through inhibition of interferon. Moreover, these results demonstrate that STING signaling and interferon production is regulated by ROS.

immunology↗

bioRxiv2018

Transcriptome profiling of pathogen-specific CD4 T cells identifies T-cell-intrinsic caspase-1 as an important regulator of Th17 differentiation

One sentence summaryOur study revealed that DCs shape distinct pathogen-specific CD4 T cell transcriptome and from which, we discovered an unexpected role for T-cell-intrinsic caspase-1 in promoting Th17 differentiation.\n\nABSTRACTDendritic cells (DCs) are critical for priming and differentiation of pathogen-specific CD4 T cells. However, to what extent innate cues from DCs dictate transcriptional changes in T cells leading to effector heterogeneity remains elusive. Here we have used an in vitro approach to prime naive CD4 T cells by DCs stimulated with distinct pathogens. We have found that such pathogen-primed CD4 T cells express unique transcriptional profiles dictated by the nature of the priming pathogen. In contrast to cytokine-polarized Th17 cells that display signatures of terminal differentiation, pathogen-primed Th17 cells maintain a high degree of heterogeneity and plasticity. Further analysis identified caspase-1 as one of the genes upregulated only in pathogen-primed Th17 cells but not in cytokine-polarized Th17 cells. T-cell-intrinsic caspase-1, independent of its function in inflammasome, is critical for inducing optimal pathogen-driven Th17 responses. More importantly, T cells lacking caspase-1 fail to induce colitis following transfer into RAG-deficient mice, further demonstrating the importance of caspase-1 for the development of pathogenic Th17 cells in vivo. This study underlines the importance of DC-mediated priming in identifying novel regulators of T cell differentiation.

immunology↗