Dataset Information

Exposure of Microglia to Interleukin-4 Represses NF-κB-Dependent Transcription of Toll-Like Receptor-Induced Cytokines.

ABSTRACT: Interleukin (IL)-4 is a cytokine that affects both adaptive and innate immune responses. In the central nervous system, microglia express IL-4 receptors and it has been described that IL-4-exposed microglia acquire anti-inflammatory properties. We here demonstrate that IL-4 exposure induces changes in the cell surface protein expression profile of primary rhesus macaque microglia and enhances their potential to induce proliferation of T cells with a regulatory signature. Moreover, we show that Toll like receptor (TLR)-induced cytokine production is broadly impaired in IL-4-exposed microglia at the transcriptional level. IL-4 type 2 receptor-mediated signaling is shown to be crucial for the inhibition of microglial innate immune responses. TLR-induced nuclear translocalization of NF-κB appeared intact, and we found no evidence for epigenetic modulation of target genes. By contrast, nuclear extracts from IL-4-exposed microglia contained significantly less NF-κB capable of binding to its DNA consensus site. Further identification of the molecular mechanisms that underlie the inhibition of TLR-induced responses in IL-4-exposed microglia may aid the design of strategies that aim to modulate innate immune responses in the brain, for example in gliomas.

SUBMITTER: Zuiderwijk-Sick EA

PROVIDER: S-EPMC8645606 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Exposure of Microglia to Interleukin-4 Represses NF-κB-Dependent Transcription of Toll-Like Receptor-Induced Cytokines.

Zuiderwijk-Sick Ella A EA van der Putten Céline C Timmerman Raissa R Veth Jennifer J Pasini Erica M EM van Straalen Linda L van der Valk Paul P Amor Sandra S Bajramovic Jeffrey J JJ

Frontiers in immunology 20211122

Interleukin (IL)-4 is a cytokine that affects both adaptive and innate immune responses. In the central nervous system, microglia express IL-4 receptors and it has been described that IL-4-exposed microglia acquire anti-inflammatory properties. We here demonstrate that IL-4 exposure induces changes in the cell surface protein expression profile of primary rhesus macaque microglia and enhances their potential to induce proliferation of T cells with a regulatory signature. Moreover, we show that T ...[more]

PMID: 34880868

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Project description:BackgroundChronic alcohol consumption is more frequently associated with advanced, aggressive hepatocellular carcinoma (HCC) tumors. Alcohol adversely impacts ER/Golgi membrane trafficking and Golgi protein N-glycosylation in hepatocytes; these effects have been attributed (in part) to dysregulated adenosine diphosphate-ribosylation factor (ARF) GTPase signaling. Here, we investigated the role of the ARF GTPase guanine exchange factor PSD4 in HCC progression.MethodsR-based bioinformatics analysis was performed on publicly available array data. Modulating gene expression was accomplished via lentiviral vectors. Gene expression was analyzed using quantitative real-time PCR and immunoblotting. PSD4 promoter methylation was assessed using quantitative methylation-specific PCR. Phospho-p65(S276)/DNMT1 binding to the PSD4 promoter was analyzed via chromatin immunoprecipitation. We constructed ethanol/DEN-induced and DEN only-induced transgenic murine models of HCC.ResultsWe identified PSD4 as a hypermethylated, suppressed gene in alcohol-related HCC tumors; however, PSD4 was not dysregulated in all-cause HCC tumors. Certain HCC cell lines also displayed varying degrees of PSD4 downregulation. PSD4 overexpression or knockdown decreased and increased cell migration and invasiveness, respectively. Mechanistically, PSD4 transcription was repressed by TNF-α-induced phospho-p65(S276)'s recruitment of DNA methyltransferase 1 (DNMT1), resulting in PSD4 promoter methylation. PSD4 inhibited pro-EMT CDC42 activity, resulting in downregulation of E-cadherin and upregulation of N-cadherin and vimentin. Hepatocyte-specific PSD4 overexpression reduced ethanol/DEN-induced HCC tumor progression and EMT marker expression in vivo.ConclusionsPSD4 is a hypermethylated, suppressed gene in alcohol-related HCC tumors that negatively modulated pro-EMT CDC42 activity. Furthermore, we present a novel phospho-NF-κB p65(S276)/DNMT1-mediated promoter methylation mechanism by which TNF-α/NF-κB signaling represses PSD4 transcription in HCC cells.

Project description:UnlabelledCharacterizing the cellular factors that play a role in the HIV replication cycle is fundamental to fully understanding mechanisms of viral replication and pathogenesis. Whole-genome small interfering RNA (siRNA) screens have identified positive and negative regulators of HIV replication, providing starting points for investigating new cellular factors. We report here that silencing of the deubiquitinase cylindromatosis protein (CYLD), increases HIV infection by enhancing HIV long terminal repeat (LTR)-driven transcription via the NF-κB pathway. CYLD is highly expressed in CD4(+) T lymphocytes, monocyte-derived macrophages, and dendritic cells. We found that CYLD silencing increases HIV replication in T cell lines. We confirmed the positive role of CYLD silencing in HIV infection in primary human CD4(+) T cells, in which CYLD protein was partially processed upon activation. Lastly, Jurkat T cells latently infected with HIV (JLat cells) were more responsive to phorbol 12-myristate 13-acetate (PMA) reactivation in the absence of CYLD, indicating that CYLD activity could play a role in HIV reactivation from latency. In summary, we show that CYLD acts as a potent negative regulator of HIV mRNA expression by specifically inhibiting NF-κB-driven transcription. These findings suggest a function for this protein in modulating productive viral replication as well as in viral reactivation.ImportanceHIV transcription is regulated by a number of host cell factors. Here we report that silencing of the lysine 63 deubiquitinase CYLD increases HIV transcription in an NF-κB-dependent manner. We show that CYLD is expressed in HIV target cells and that its silencing increases HIV infection in transformed T cell lines as well as primary CD4(+) T cells. Similarly, reactivation of latent provirus was facilitated in the absence of CYLD. These data suggest that CYLD, which is highly expressed in CD4(+) T cells, can control HIV transcription in productive infection as well as during reactivation from latency.

Dataset Information

Exposure of Microglia to Interleukin-4 Represses NF-κB-Dependent Transcription of Toll-Like Receptor-Induced Cytokines.

Publications

Exposure of Microglia to Interleukin-4 Represses NF-κB-Dependent Transcription of Toll-Like Receptor-Induced Cytokines.

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