IFN-β Secretion Research Articles

Human Milk Oligosaccharide 2'-Fucosyllactose Modulates Local Viral Immune Defense by Supporting the Regulatory Functions of Intestinal Epithelial and Immune Cells.

Human milk contains bioactive components that provide protection against viral infections in early life. In particular, intestinal epithelial cells (IEC) have key regulatory roles in the prevention of enteric viral infections. Here we established an in vitro model to study the modulation of host responses against enteric viruses mimicked by poly I:C (pIC). The effects of 2′-fucosyllactose (2′FL), abundantly present in human milk, were studied on IEC and/or innate immune cells, and the subsequent functional response of the adaptive immune cells. IEC were pre-incubated with 2′FL and stimulated with naked or Lyovec™-complexed pIC (LV-pIC). Additionally, monocyte-derived dendritic cells (moDC) alone or in co-culture with IEC were stimulated with LV-pIC. Then, conditioned-moDC were co-cultured with naïve CD4+ T helper (Th)-cells. IEC stimulation with naked or LV-pIC promoted pro-inflammatory IL-8, CCL20, GROα and CXCL10 cytokine secretion. However, only exposure to LV-pIC additionally induced IFNβ, IFNλ1 and CCL5 secretion. Pre-incubation with 2′FL further increased pIC induced CCL20 secretion and LV-pIC induced CXCL10 secretion. LV-pIC-exposed IEC/moDC and moDC cultures showed increased secretion of IL-8, GROα, IFNλ1 and CXCL10, and in the presence of 2′FL galectin-4 and -9 were increased. The LV-pIC-exposed moDC showed a more pronounced secretion of CCL20, CXCL10 and CCL5. The moDC from IEC/moDC cultures did not drive T-cell development in moDC/T-cell cultures, while moDC directly exposed to LV-pIC secreted Th1 driving IL-12p70 and promoted IFNγ secretion by Th-cells. Hereby, a novel intestinal model was established to study mucosal host-defense upon a viral trigger. IEC may support intestinal homeostasis, regulating local viral defense which may be modulated by 2′FL. These results provide insights regarding the protective capacity of human milk components in early life.

Decreased leukocyte exhaustion is associated with decreased IFN-β and increased α-defensin-1 levels in type-2 diabetes.

Pan-leukocyte exhaustion is a physiological process associated with immune homeostasis. Too much of immune exhaustion can lead to immune impairment and increased susceptibility to infections and cancer; too little can lead to chronic inflammation. Since type-2 diabetes subjects have both impaired immunity and metainflammation, we looked at TLR induced pan-immune exhaustion and its regulation, in these subjects. TLR induced expression of PD-1 and CTLA-4 in T cells, B cells, monocytes and neutrophils, in whole blood cultures, were quantified by flowcytometry. Circulating levels and in vitro secretion of IFN-β and α-Defensin-1 (α-DEF-1) were quantified by ELISA. TLR induced expression of PU.1, IRF-3,-4 and -5 in whole blood cultures was quantified by qRT-PCR. Systemic lipid and protein peroxidation was quantified by spectrophotometry. TLR induced expression of PD-1 (in monocytes) and CTLA-4 expression (in B cells and neutrophils) were decreased in drug naive newly diagnosed diabetes patients. This was associated with decreased secretion and circulating levels of IFN-β and increased secretion and circulating levels of α-DEF-1 in these subjects. No major derangement in the transcriptional network was seen. Many of these defects were only partially rectified in those under treatment. Together, we hypothesize that the high defensin levels could inhibit TLR signalling leading to reduced IFN-β levels, which in turn could lead to reduced expression of PD-1 and CTLA-4 in the immune cells. This effect along with systemic redox stress could fuel metainflammation in type-2 diabetes.

Adenosine Deaminase 2 Deficiency (DADA2): A Crosstalk Between Innate and Adaptive Immunity.

Deficiency of Adenosine deaminase 2 (DADA2) is a monogenic autoinflammatory disorder presenting with a broad spectrum of clinical manifestations, including immunodeficiency, vasculopathy and hematologic disease. Biallelic mutations in ADA2 gene have been associated with a decreased ADA2 activity, leading to reduction in deamination of adenosine and deoxyadenosine into inosine and deoxyinosine and subsequent accumulation of extracellular adenosine. In the early reports, the pivotal role of innate immunity in DADA2 pathogenic mechanism has been underlined, showing a skewed polarization from the M2 macrophage subtype to the proinflammatory M1 subtype, with an increased production of inflammatory cytokines such as TNF-α. Subsequently, a dysregulation of NETosis, triggered by the excess of extracellular Adenosine, has been implicated in the pathogenesis of DADA2. In the last few years, evidence is piling up that adaptive immunity is profoundly altered in DADA2 patients, encompassing both T and B branches, with a disrupted homeostasis in T-cell subsets and a B-cell skewing defect. Type I/type II IFN pathway upregulation has been proposed as a possible core signature in DADA2 T cells and monocytes but also an increased IFN-β secretion directly from endothelial cells has been described. So far, a unifying clear pathophysiological explanation for the coexistence of systemic inflammation, immunedysregulation and hematological defects is lacking. In this review, we will explore thoroughly the latest understanding regarding DADA2 pathophysiological process, with a particular focus on dysregulation of both innate and adaptive immunity and their interacting role in the development of the disease.

TIRAP/Mal Positively Regulates TLR8-Mediated Signaling via IRF5 in Human Cells

Toll-like receptor 8 (TLR8) recognizes single-stranded RNA of viral and bacterial origin as well as mediates the secretion of pro-inflammatory cytokines and type I interferons by human monocytes and macrophages. TLR8, as other endosomal TLRs, utilizes the MyD88 adaptor protein for initiation of signaling from endosomes. Here, we addressed the potential role of the Toll-interleukin 1 receptor domain-containing adaptor protein (TIRAP) in the regulation of TLR8 signaling in human primary monocyte-derived macrophages (MDMs). To accomplish this, we performed TIRAP gene silencing, followed by the stimulation of cells with synthetic ligands or live bacteria. Cytokine-gene expression and secretion were analyzed by quantitative PCR or Bioplex assays, respectively, while nuclear translocation of transcription factors was addressed by immunofluorescence and imaging, as well as by cell fractionation and immunoblotting. Immunoprecipitation and Akt inhibitors were also used to dissect the signaling mechanisms. Overall, we show that TIRAP is recruited to the TLR8 Myddosome signaling complex, where TIRAP contributes to Akt-kinase activation and the nuclear translocation of interferon regulatory factor 5 (IRF5). Recruitment of TIRAP to the TLR8 signaling complex promotes the expression and secretion of the IRF5-dependent cytokines IFNβ and IL-12p70 as well as, to a lesser degree, TNF. These findings reveal a new and unconventional role of TIRAP in innate immune defense.

CASTING: A Potent Supramolecular Strategy to Cytosolically Deliver STING Agonist for Cancer Immunotherapy and SARS-CoV-2 Vaccination

CASTING: A Potent Supramolecular Strategy to Cytosolically Deliver STING Agonist for Cancer Immunotherapy and SARS-CoV-2 Vaccination

Nucleopore Traffic Is Hindered by SARS-CoV-2 ORF6 Protein to Efficiently Suppress IFN-β and IL-6 Secretion.

A weak production of INF-β along with an exacerbated release of pro-inflammatory cytokines have been reported during infection by the novel SARS-CoV-2 virus. SARS-CoV-2 encodes several proteins that are able to counteract the host immune system, which is believed to be one of the most important features contributing to the viral pathogenesis and development of a severe clinical outcomes. Previous reports demonstrated that the SARS-CoV-2 ORF6 protein strongly suppresses INF-β production by hindering the RIG-I, MDA-5, and MAVS signaling cascade. In the present study, we better characterized the mechanism by which the SARS-CoV-2 ORF6 counteracts IFN-β and interleukin-6 (IL-6), which plays a crucial role in the inflammation process associated with the viral infection. In the present study, we demonstrated that the SARS-CoV-2 ORF6 protein has evolved an alternative mechanism to guarantee host IFN-β and IL-6 suppression, in addition to the transcriptional control exerted on the genes. Indeed, a block in movement through the nucleopore of newly synthetized messenger RNA encoding the immune-modulatory cytokines IFN-β and IL-6 are reported here. The ORF6 accessory protein of SARS-CoV-2 displays a multifunctional activity and may represent one of the most important virulence factors. Where conventional antagonistic strategies of immune evasion—such as the suppression of specific transcription factors (e.g., IRF-3, STAT-1/2)—would not be sufficient, the SARS-CoV-2 ORF6 protein is the trump card for the virus, also blocking the movement of IFN-β and IL-6 mRNAs from nucleus to cytoplasm. Conversely, we showed that nuclear translocation of the NF-κB transcription factor is not affected by the ORF6 protein, although inhibition of its cytoplasmic activation occurred. Therefore, the ORF6 protein exerts a 360-degree inhibition of the antiviral response by blocking as many critical points as possible.

Early IFNβ secretion determines variable downstream IL-12p70 responses upon TLR4 activation.

The interleukin-12 (IL-12) family comprises the only heterodimeric cytokines mediating diverse functional effects. We previously reported a striking bimodal IL-12p70 response to lipopolysaccharide (LPS) stimulation in healthy donors. Herein, we demonstrate that interferon β (IFNβ) is a major upstream determinant of IL-12p70 production, which is also associated with numbers and activation of circulating monocytes. Integrative modeling of proteomic, genetic, epigenomic, and cellular data confirms IFNβ as key for LPS-induced IL-12p70 and allowed us to compare the relative effects of each of these parameters on variable cytokine responses. Clinical relevance of our findings is supported by reduced IFNβ-IL-12p70 responses in patients hospitalized with acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or chronically infected with hepatitis C (HCV). Importantly, these responses are resolved after viral clearance. Our systems immunology approach defines a better understanding of IL-12p70 and IFNβ in healthy and infected persons, providing insights into how common genetic and epigenetic variation may impact immune responses to bacterial infection.

The E248R protein of African swine fever virus inhibits the cGAS-STING-mediated innate immunity

We researched the mechanism of African swine fever virus (ASFV) protein E248R in regulating the cGAS-STING pathway. First, we verified via the dual-luciferase reporter assay system that E248R protein inhibited the secretion of IFN-β induced by cGAS-STING or HT-DNA in a dose-dependent manner. The relative quantitative PCR analysis indicated that the overexpression of E248R inhibited HT-DNA-induced transcription of IFN-b1, RANTES, IL-6, and TNF-α in PK-15 cells. Next, we found that E248R interacted with STING by co-immunoprecipitation assay and laser confocal microscopy. Finally, we demonstrated that E248R inhibited the expression of STING protein by using Western blotting. We demonstrated for the first time that the E248R protein of ASFV suppressed the host innate immune response via inhibiting STING expression. The results are pivotal in extending the understanding of the ASFV immune escape and can guide the design of vaccines against ASFV.

Proceedings to the 7th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA)

Proceedings to the 7th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA)

Screening of Antiviral Components of Yinhuapinggan Granule and Protective Effects of Yinhuapinggan Granule on MDCK Cells with Influenza A/H1N1 Virus.

Background Traditional Chinese medicine Yinhuapinggan granule (YHPG) has been used for treating upper respiratory tract infection like influenza, cough, and viral pneumonia. However, its active ingredients that really exert the main efficacy have not been well elucidated. This study is aimed at screening its antiviral components and investigating the potential therapeutic mechanisms of YHPG against the influenza A/PR8/34 (H1N1) virus in Madin Darby canine kidney (MDCK). Methods MDCK cells were infected with the influenza virus and then treated with ribavirin, YHPG, and main active ingredients in YHPG. Based on the maximum nontoxic concentration (TC0), half-maximal toxic concentration (TC50), half-maximal inhibitory concentration (IC50), and therapeutic index (TI), interferon-β (IFN-β) and interleukin-6 (IL-6) levels were measured using enzyme-linked immunosorbent assay (ELISA), and the gene expression of TLR7, MyD88, tumor necrosis factor receptor-associated factor 6 (TRAF6), c-Jun amino terminal kinase (JNK), p38 mitogen-activated protein kinase (p38 MAPK), and p65 nuclear transcription factor-kappa B (p65 NF-κB) was quantified using reverse transcription-polymerase chain reaction (RT-PCR). Results The results indicated that the components of YHPG, such as ephedrine hydrochloride, pseudoephedrine hydrochloride, chlorogenic acid, and emodin, had significant antiviral effects. High and medium doses of YHPG effectively reduced the cytopathic effect (CPE) and significantly decreased IFN-β and IL-6 levels in the supernatant. Simultaneously, the transcript levels of TLR7, MyD88, TRAF6, JNK, p38 MAPK, and p65 NF-κB decreased in infected MDCK cells. Moreover, a certain dose-dependent relationship among different groups of YHPG was observed. Conclusions These results indicated that YHPG and the components of YHPG had a significant inhibitory function on the proliferation of the H1N1 virus. The mechanism might be associated with suppressing the activation of the TLR7/MyD88 signaling pathway, a decrease in the mRNA expression of key target genes, and inhibition of IFN-β and IL-6 secretion.

Monocyte and Macrophage Lipid Accumulation Results in Down-Regulated Type-I Interferon Responses.

Macrophages are critical components of atherosclerotic lesions and their pro- and anti-inflammatory responses influence atherogenesis. Type-I interferons (IFNs) are cytokines that play an essential role in antiviral responses and inflammatory activation and have been shown to promote atherosclerosis. Although the impact of type-I IFNs on macrophage foam cell formation is well-documented, the effect of lipid accumulation in monocytes and macrophages on type-I IFN responses remains unknown. Here we examined IFN stimulated (ISG) and non-ISG inflammatory gene expression in mouse and human macrophages that were loaded with acetylated LDL (acLDL), as a model for foam cell formation. We found that acLDL loading in mouse and human macrophages specifically suppressed expression of ISGs and IFN-β secretion, but not other pro-inflammatory genes. The down regulation of ISGs could be rescued by exogenous IFN-β supplementation. Activation of the cholesterol-sensing nuclear liver X receptor (LXR) recapitulated the cholesterol-initiated type-I IFN suppression. Additional analyses of murine in vitro and in vivo generated foam cells confirmed the suppressed IFN signaling pathways and suggest that this phenotype is mediated via down regulation of interferon regulatory factor binding at gene promoters. Finally, RNA-seq analysis of monocytes of familial hypercholesterolemia (FH) patients also showed type-I IFN suppression which was restored by lipid-lowering therapy and not present in monocytes of healthy donors. Taken together, we define type-I IFN suppression as an athero-protective characteristic of foamy macrophages. These data provide new insights into the mechanisms that control inflammatory responses in hyperlipidaemic settings and can support future therapeutic approaches focusing on reprogramming of macrophages to reduce atherosclerotic plaque progression and improve stability.

Bioinspired magnetic nanocomplexes amplifying STING activation of tumor-associated macrophages to potentiate cancer immunotherapy

Insufficient tumor-infiltration of the cytotoxic T lymphocytes (CTLs) and immunosuppressive tumor microenvironment (ITM) severely hinder T cell-based cancer immunotherapy. In this study, we developed bioinspired magnetic nanocomplexes (m-PUNCs) to boost antitumor immunogenicity through amplifying stimulator of interferon genes (STING)-regulated immune cascade of tumor-associated macrophages (TAMs). m-PUNCs were engineered by integrating ultrasmall iron oxide nanoparticles (UIONPs), tumor acidity-ionizable of poly(ethylene glycol)-block-poly(2-(hexamethyleneimino)) ethyl methacrylate (PHMA) diblock copolymer, and red blood cell membrane into a single nanoplatform. The resultant m-PUNCs specifically accumulated at the tumor site via passive targeting effect, which were subsequently phagocytized with TAMs. The UIONPs moiety efficiently relieved the ITM by repolarizing TAMs into M1-phenotype, while PHMA activated the STING pathway and stimulated type-I interferon (e.g., IFN-β) secretion in TAMs. Consequently, IFN-β attracted the conventional type I dendritic cells for priming the tumor-specific CTLs. In combination with immune checkpoint blockade therapy with the antibody against programmed death ligand 1, m-PUNCs remarkably inhibited tumor growth and prolonged the survival of both melanoma and breast tumor-bearing mouse model. This study demonstrated the immune cascade of magnetic nanocomplexes-mediated TAM repolarization and subsequent STING activation, which might provide novel insights for potentiating cancer immunotherapy.

ELISA-based quantification of type I IFN secretion by irradiated cancer cells.

Cancer cell-intrinsic type I interferon (IFN-I) activation is required to initiate early innate immune responses and the subsequent radiation-induced anti-tumor immunity. Investigating the secretion of IFN-I cytokines in response to radiation therapy (RT) is therefore a critical readout for selecting the best immunogenic radiation dose-fractionation regimen. In this chapter, we present different ELISA-based quantification techniques that can be utilized to assess the secretion of tumor-derived IFN-I cytokines, namely IFN-α and IFN-β.

Interactions of Muscovy duck reovirus, gut microbiota, and host innate immunity: Transcriptome and gut microbiota analysis

It has been shown that Muscovy duck reovirus (MDRV) infection causes severe intestinal barrier damage and intestinal mucosal immune suppression. The health and balance of gut microbes is essential for the progression of intestinal infectious diseases. To investigate the interaction of MDRV, intestinal bacteria with host intestinal innate immunity, an MDRV contact-infection model was established in this study. High-throughput sequencing technology was used to sequence 16S rDNA and transcripts in ileal samples from experimental Muscovy ducklings. Our results suggest that intestinal opportunistic pathogens such as Streptococcus and Corynebacterium proliferated massively in MDRV-infected Muscovy ducklings. The body initiates antiviral and antibacterial immunity and actively fights the infection of gut microbes. The synthesis of peptidoglycan, lipopolysaccharide, and flagellin by intestinal bacteria activates the Toll-like receptor signaling pathway resulting in increased secretion of IFN-β, IL-1β, and IL-8. The RIG-I-like receptor signaling pathway is an important signaling pathway for the interaction between MDRV and the host. At the same time, we also observed that multiple genes in the JAK-STAT signaling pathway were significantly different. These genes are important targets for studying the immunosuppression caused by MDRV. In conclusion, we analyzed the interaction of MDRV, intestinal flora and host immune system during MDRV infection, which provides a basis for the further study on the mechanism of intestinal immunosuppression caused by MDRV.

Pharmacokinetics and Pharmacodynamics of Huanglian-Houpo Decoction Based on Berberine Hydrochloride and Magnolol Against H1N1 Influenza Virus.

Background and ObjectivesHuanglian-Houpo decoction (HH), which is recorded in the famous traditional Chinese medicine monograph “Puji Fang,” contains two individual herbs, Huanglian (Rhizoma coptidis) and Houpo (Magnoliae officinalis cortex). It was regularly used to treat seasonal epidemic colds and influenzas in ancient China. Our laboratory discovered that HH has a significant anti-H1N1 influenza virus effect. However, no pharmacokinetic and pharmacodynamic data concerning the anti-H1N1 influenza virus activity of HH are available to date. In the current study, the concentration-time profiles of two major components of HH, berberine and magnolol, in rat plasma were investigated.MethodsAn integrate pharmacokinetic approach was developed for evaluating the holistic pharmacokinetic characteristics of berberine and magnolol from HH. Additionally, the inhibition rate and levels of IFN-β in MDCK cells infected by influenza virus were analyzed. Data were calculated using 3p97 with pharmacokinetic analysis.ResultsThe estimated pharmacokinetic parameters were maximum plasma concentration (Cmax) 0.9086 μg/ml, area under the concentration-time curve (AUC) 347.74 μg·min/ml, and time to reach Cmax (Tmax) 64.69 min for berberine and Cmax = 0.9843 μg/ml, AUC= 450.64 μg·min/ml, Tmax = 56.86 min for magnolol, respectively. Furthermore, integrated pharmacokinetic and pharmacodynamic analysis showed that the highest plasma concentration, inhibition rate and interferon-β (IFN-β) secretion of HH first increased and then weakened over time, reaching their peaks at 60 min. The plasma concentration of HH is directly related to the anti-influenza virus effect.ConclusionThe results indicated that berberine and magnolol are the main active ingredients of HH related to its anti-influenza virus effect, which is related to the improvement of IFN-β secretion.

The STING-IRF3 pathway contributes to paraquat-induced acute lung injury

Immune and inflammatory responses play significant roles in paraquat (PQ)-induced acute lung injury (ALI), but the specific mechanisms remain unclear. Our study aimed to investigate the action of STING-IRF3 signaling on PQ-induced ALI in mice. Following PQ administration, samples were collected at 2, 12, 24, and 48 h for in vivo studies, and 24 h for in vitro studies. Following PQ administration (30 mg/kg, i.p.), injury to mouse lungs was evaluated by H&E staining and wet/dry ratios, and lung oxidative damage was evaluated by MDA and SOD assays. The mRNA levels of Sting, Irf3, and Ifnβ were detected by RT-PCR, the expression of STING and IRF3 were assessed by western blotting and IHC/IF, and the secretion of IFNβ was detected by ELISA. In vivo, PQ administration induced pathological changes and increased wet/dry ratios in lungs after 48 h. Sting, Irf3, and Ifnβ mRNA levels in lung tissues, STING and pIRF3 protein levels in lung tissues, and IFNβ secretion in serum, were upregulated by PQ in a time-dependent manner. PQ administration promoted IRF3 nuclear translocation in lung tissues after 48 h. The above changes were all attenuated by dexamethasone treatment (5 mg/kg, i.p., qd). In vitro, PQ induced STING and IRF3 translocation. Irf3 or Sting silencing decreased the mRNA levels and supernatant secretion of IFNβ in PQ-treated RAW264.7 mouse macrophages. Sting silencing also inhibited the protein and mRNA levels of IRF3 in vitro. Our study suggests that STING-IRF3 signaling contributes to PQ-induced ALI, providing new information for future treatment strategies.

Clinically used JAK inhibitor blunts dsRNA-induced inflammation and calcification in aortic valve interstitial cells.

Calcific aortic valve disease (CAVD) is the most prevalent valvulopathy worldwide. Growing evidence supports a role for viral and cell-derived double-stranded (ds)-RNA in cardiovascular pathophysiology. Poly(I:C), a dsRNA surrogate, has been shown to induce inflammation, type I interferon (IFN) responses, and osteogenesis through Toll-like receptor 3 in aortic valve interstitial cells (VIC). Here, we aimed to determine whether IFN signaling via Janus kinase (JAK)/Signal transducers and activators of transcription (STAT) mediates dsRNA-induced responses in primary human VIC. Western blot, ELISA, qPCR, calcification, flow cytometry, and enzymatic assays were performed to evaluate the mechanisms of dsRNA-induced inflammation and calcification. Poly(I:C) triggered a type I IFN response characterized by IFN-regulatory factors gene upregulation, IFN-β secretion, and STAT1 activation. Additionally, Poly(I:C) promoted VIC inflammation via NF-κB and subsequent adhesion molecule expression, and cytokine secretion. Pretreatment with ruxolitinib, a clinically used JAK inhibitor, abrogated these responses. Moreover, Poly(I:C) promoted a pro-osteogenic phenotype and increased VIC calcification to a higher extent in cells from males. Inhibition of JAK with ruxolitinib or a type I IFN receptor blocking antibody blunted Poly(I:C)-induced calcification. Mechanistically, Poly(I:C) promoted VIC apoptosis in calcification medium, which was inhibited by ruxolitinib. Moreover, Poly(I:C) co-operated with IFN-γ to increase VIC calcification by synergistically activating extracellular signal-regulated kinases and hypoxia-inducible factor-1α pathways. In conclusion, JAK/STAT signaling mediates dsRNA-triggered inflammation, apoptosis, and calcification and may contribute to a positive autocrine loop in human VIC in the presence of IFN-γ. Blockade of dsRNA responses with JAK inhibitors may be a promising therapeutic avenue for CAVD.

Tofacitinib therapy intercepts macrophage metabolic reprogramming instigated by SARS-CoV-2 Spike protein.

The molecular mechanism of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Spike protein was characterized to identify novel therapies. The impact of tofacitinib, IL‐6R Ab, or TNFi therapy was determined on Spike protein or LPS/IFN‐γ‐induced signaling, inflammation, and metabolic reprogramming in MΦs and/or rheumatoid arthritis (RA) fibroblast‐like synoviocyte (FLS). ACE2 frequency was markedly expanded in MΦs compared to T cells and RA FLS. Tofacitinib suppresses Spike protein potentiated STAT1 signaling, whereas this function was unchanged by TNFi. Tofacitinib impairs IL‐6/IFN/LPS‐induced STAT1 and STAT3 phosphorylation in RA MΦs and FLS. Interestingly, tofacitinib had a broader inhibitory effect on the monokines, glycolytic regulators, or oxidative metabolites compared to IL‐6R Ab and TNFi in Spike‐protein‐activated MΦs. In contrast, all three therapies disrupted IFN‐α and IFN‐β secretion in response to Spike protein; nonetheless, the IFN‐γ was only curtailed by tofacitinib or IL‐6R Ab. While tofacitinib counteracted MΦ metabolic rewiring instigated by Spike protein, it was inconsequential on the glycolysis expansion mediated via HK2 and/or LDHA in the activated RA MΦ and FLS. Nevertheless, the potentiated inflammatory response and the diminished oxidative phosphorylation modulated by Spike protein and/or LPS/IFN‐γ stimulation in MΦs or RA FLS were reversed by tofacitinib. In conclusion, tofacitinib suppresses MΦ inflammation and immunometabolism triggered by Spike protein and may provide a promising strategy for COVID‐19 patients.

A20/Nrdp1 interaction alters the inflammatory signaling profile by mediating K48- and K63-linked polyubiquitination of effectors MyD88 and TBK1

A20 is a potent anti-inflammatory protein that mediates both inflammation and ubiquitination in mammals, but the related mechanisms are not clear. In this study, we performed mass spectrometry (MS) screening, gene ontology (GO) analysis, and coimmunoprecipitation (co-IP) in a lipopolysaccharide (LPS)-induced inflammatory cell model to identify novel A20-interacting proteins. We confirmed that the E3 ubiquitin ligase Nrdp1, also known as ring finger protein 41 (RNF41), interacted with A20 in LPS-stimulated cells. Further co-IP analysis demonstrated that when A20 was knocked out, degradation-inducing K48-linked ubiquitination of inflammatory effector MyD88 was decreased, but protein interaction-mediating K63-linked ubiquitination of another inflammatory effector TBK1 was increased. Moreover, western blot experiments showed that A20 inhibition induced an increase in levels of MyD88 and phosphorylation of downstream effector proteins as well as of TBK1 and a downstream effector, while Nrdp1 inhibition induced an increase in MyD88 but a decrease in TBK1 levels. When A20 and Nrdp1 were coinhibited, no further change in MyD88 was observed, but TBK1 levels were significantly decreased compared with those upon A20 inhibition alone. Gain- and loss-of-function analyses revealed that the ZnF4 domain of A20 is required for Nrdp1 polyubiquitination. Upon LPS stimulation, the inhibition of Nrdp1 alone increased the secretion of IL-6 and TNF-α but decreased IFN-β secretion, as observed in other studies, suggesting that Nrdp1 preferentially promotes the production of IFN-β. Taken together, these results demonstrated that A20/Nrdp1 interaction is important for A20 anti-inflammation, thus revealing a novel mechanism for the anti-inflammatory effects of A20.

Ribosomal Protein L13 Participates in Innate Immune Response Induced by Foot-and-Mouth Disease Virus.

In addition to ribosomal protein synthesis and protein translation, ribosomal proteins also participate in tumorigenesis and tumor progression, immune responses, and viral replication. Here, we show that ribosomal protein L13 (RPL13) participates in the antiviral immune response induced by foot-and-mouth disease virus (FMDV), inhibiting FMDV replication. The overexpression of RPL13 promoted the induction and activation of the promoters of the nuclear factor-κB (NF-κB) and interferon-β (IFN-β) genes, and the expression and protein secretion of the antiviral factor IFN-β and proinflammatory cytokine interleukin-6 (IL-6). The knockdown of RPL13 had the opposite effects. We also found that the FMDV 3Cpro protease interacts with RPL13, and that its activity reduces the expression of RPL13, thus antagonizing the RPL13-mediated antiviral activity. This study extends our knowledge of the extraribosomal functions of ribosomal proteins and provides new scientific information on cellular antiviral defenses and virus-antagonizing mechanisms.