Immune quorum sensing dictates IFN-I response dynamics in human plasmacytoid dendritic cells

Type I interferons (IFN-Is) are key in fighting viral infections, but also serve major roles beyond antiviral immunity. Crucial is the tight regulation of IFN-I responses, while excessive levels are harmful to the cells. In essence, immune responses are generated by single cells making their own decisions, which are based on the signals they perceive. Additionally, immune cells must anticipate the future state of their environment, thereby weighing the costs and benefits of each possible outcome, in the presence of other potentially competitive decision makers (i.e., IFN-I producing cells). A rather new cellular communication mechanism called quorum sensing describes the effect of cell density on cellular secretory behaviors, which fits well with matching the right amount of IFN-Is produced to fight an infection. More competitive decision makers must contribute relatively less and vice versa. Intrigued by this concept, we assessed the effects of immune quorum sensing in pDCs, specialized immune cells known for their ability to mass produce IFN-Is. Using conventional microwell assays and droplet-based microfluidics assays, we were able the characterize the effect of quorum sensing in human primary immune cells in vitro. These insights open new avenues to manipulate IFN-I response dynamics in pathological conditions affected by aberrant IFN-I signaling.

Type I interferon pathway genetic variants in severe COVID-19

Coronavirus Disease 2019 (COVID-19) is an infectious disease caused by SARS-CoV-2. According to the World Health Organization (WHO), there have been over 760 million reported cases and over 6 million deaths caused by this disease worldwide. The severity of COVID-19 is based on symptoms presented by the patient and is divided as asymptomatic, mild, moderate, severe, and critical. The manifestations are interconnected with genetic variations. The innate immunity is the quickest response mechanism of an organism against viruses. Type I interferon pathway plays a key role in antiviral responses due to viral replication inhibition in infected cells and adaptive immunity stimulation induced by interferon molecules. Thus, variants in type I interferon pathway's genes are being studied in different COVID-19 manifestations. This review summarizes the role of variants in type I interferon pathway's genes on prognosis and severity progression of COVID-19.

Age-related transcript changes in type I interferon signaling in children and adolescents with long COVID

SARS-CoV-2 typically causes mild symptoms in children, but evidence suggests that persistent immunopathological changes may lead to long COVID (LC). To explore the interplay between LC and innate immunity, we assessed the type I interferon (IFN-I) response in children and adolescents with LC symptoms (LC; n = 28). This was compared with age-matched SARS-CoV-2 recovered participants without LC symptoms (MC; n = 28) and healthy controls (HC; n = 18). We measured the mRNA expression of IFN-I (IFN-α/β/ε/ω), IFN-I receptor (IFNAR1/2), and ISGs (ISG15, ISG56, MxA, IFI27, BST2, LY6E, OAS1, OAS2, OAS3, and MDA5) in PBMCs collected 3-6 months after COVID-19. LC adolescents (12-17 years) had higher transcript levels of IFN-β, IFN-ε, and IFN-ω than HC, whereas LC children (6-11 years) had lower levels than HC. In adolescents, increased levels of IFN-α, IFN-β, and IFN-ω mRNAs were found in the LC group compared with MC, while lower levels were observed in LC children than MC. Adolescents with neurological symptoms had higher IFN-α/β mRNA levels than MC. LC and MC participants showed decreased expression of ISGs and IFNAR1, but increased expression of IFNAR2, than HC. Our results show age-related changes in the expression of transcripts involved in the IFN-I signaling pathway in children and adolescents with LC.

cGAS-STING pathway mediates activation of dendritic cell sensing of immunogenic tumors

Type I interferons (IFN-I) play pivotal roles in tumor therapy for three decades, underscoring the critical importance of maintaining the integrity of the IFN-1 signaling pathway in radiotherapy, chemotherapy, targeted therapy, and immunotherapy. However, the specific mechanism by which IFN-I contributes to these therapies, particularly in terms of activating dendritic cells (DCs), remains unclear. Based on recent studies, aberrant DNA in the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signaling pathway, which in turn produces IFN-I, which is essential for antiviral and anticancer immunity. Notably, STING can also enhance anticancer immunity by promoting autophagy, inflammation, and glycolysis in an IFN-I-independent manner. These research advancements contribute to our comprehension of the distinctions between IFN-I drugs and STING agonists in the context of oncology therapy and shed light on the challenges involved in developing STING agonist drugs. Thus, we aimed to summarize the novel mechanisms underlying cGAS-STING-IFN-I signal activation in DC-mediated antigen presentation and its role in the cancer immune cycle in this review.

Salmonella T3SS-elicited inflammatory innate immune response inhibits type I IFN response in macrophages

As a gram-negative intracellular bacterial pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium) invades different cell types including macrophages. Its infection in macrophages induces robust innate immune responses that are featured by proinflammatory and type I interferon (IFN) responses. The type III secretion systems (T3SSs) of S. Typhimurium play a crucial role in activating host inflammasome pathways. It has been recognized that the inflammasome pathways inhibit the type I IFN cascade. However, the potential role of T3SS in regulating the type I IFN response and the underlying mechanisms are largely unknown. In this study, we showed that S. Typhimurium infection activated strong proinflammatory, type I IFN and IFN-stimulated genes (ISGs) expression in macrophages. Furthermore, we showed that T3SS-defective S. Typhimurium mutant ΔinvC elicited attenuated inflammatory response but enhanced type I IFN and ISGs expression. Additionally, the inhibition of caspase-1 by a specific inhibitor VX-765 resulted in increased type I IFN response. Moreover, cell-permeable pan-caspase inhibitor Z-VAD-FMK also enhanced the type I IFN response upon S. Typhimurium infection. Intriguingly, compared with exponential phase S. Typhimurium infection, stationary phase bacteria triggered higher levels of type I IFN responses. Finally, the inhibition of caspase-1 by VX-765 substantially increased the intracellular S. Typhimurium burden. In conclusion, we demonstrated that the proinflammatory response induced by S. Typhimurium T3SS can inhibit the type I IFN response, which provides insight into the role of T3SS in orchestrating innate immunity during S. Typhimurium infection.

Activation of cGAS-STING suppresses coxsackievirus replication via interferon-dependent signaling

Coxsackievirus B3 (CVB3) is a non-enveloped, single-stranded, positive RNA virus known for its role in provoking inflammatory diseases that affect the heart, pancreas, and brain, leading to conditions such as myocarditis, pancreatitis, and meningitis. Currently, there are no FDA-approved drugs treating CVB3 infection; therefore, identifying potential molecular targets for antiviral drug development is imperative. In this study, we examined the possibility of activating the cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway, a cytosolic DNA-sensing pathway that triggers a type-I interferon (IFN) response, in inhibiting CVB3 infection. We found that activation of the cGAS-STING pathway through the application of cGAS (poly dA:dT and herring testes DNA) or STING agonists (2'3'-cGAMP and diamidobenzimidazole), or the overexpression of STING, significantly suppresses CVB3 replication. Conversely, gene-silencing of STING enhances viral replication. Mechanistically, we demonstrated that cGAS-STING activation combats CVB3 infection by inducing IFN response. Notably, we discovered that knockdown of IFN-α/β receptor, a key membrane receptor in type-I IFN signaling, or inhibition of the downstream JAK1/2 signaling with ruxolitinib, mitigates the effects of STING activation, resulting in increased viral protein production. Furthermore, we investigated the interplay between CVB3 and the cGAS-STING pathway. We showed that CVB3 does not trigger cGAS-STING activation; instead, it antagonizes STING and the downstream TBK1 activation induced by cGAMP. In summary, our results provide insights into the interaction of an RNA virus and the DNA-sensing pathway, highlighting the potential for agonist activation of the cGAS-STING pathway in the development of anti-CVB3 drugs.

Echinococcus granulosus cyst fluid inhibits the type I interferon response by promoting ROS in macrophages

In cystic echinococcosis (CE), Echinococcus granulosus cystic fluid (EgCF) could impede macrophage-mediated immunity. However, whether EgCF is implicated in the type I interferon response remains to be established. Here, we revealed that EgCF reduced 2'3'-cGAMP-induced IFN-β production in macrophages by inhibiting the cGAS-STING-IRF3 signaling. EgCF also increased the intracellular reactive oxygen species (ROS) levels. Administration of the ROS inhibitor N-acetylcysteine (NAC) restored the cGAS-STING-IRF3 signaling, which, in turn, upregulated IFN-β expression. The findings disclose that EgCF could increase macrophage ROS levels, thereby blocking cGAS-STING-IRF3 signaling and repressing the IFN-I response.

Mechanism of action and treatment of type I interferon in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) caused by HBV, HCV infection, and other factors is one of the most common malignancies in the world. Although, percutaneous treatments such as surgery, ethanol injection, radiofrequency ablation, and transcatheter treatments such as arterial chemoembolization are useful for local tumor control, they are not sufficient to improve the prognosis of patients with HCC. External interferon agents that induce interferon-related genes or type I interferon in combination with other drugs can reduce the recurrence rate and improve survival in HCC patients after surgery. Therefore, in this review, we focus on recent advances in the mechanism of action of type I interferons, emerging therapies, and potential therapeutic strategies for the treatment of HCC using IFNs.

A rare manifestation of STING-associated vasculopathy with onset in infancy: a case report

BACKGROUND

STING-associated vasculopathy with onset in infancy (SAVI) is a rare type I interferonopathy caused by heterozygous variants in the STING gene. In SAVI, STING variants confer a gain-of-function which causes overactivation of type I interferon (IFN) signaling leading to autoinflammation and various degrees of immunodeficiency and autoimmunity.

CASE PRESENTATION

We report the case of a 5 year old child and his mother, both of whom presented with systemic inflammatory symptoms yet widely varying organ involvement, disease course and therapeutic response. Genetic testing revealed a heterozygous STING variant, R281Q, in the child and his mother that had previously been associated with SAVI. However, in contrast to previously reported SAVI cases due to the R281Q variant, our patients showed an atypical course of disease with alopecia totalis in the child and a complete lack of lung involvement in the mother.

CONCLUSIONS

Our findings demonstrate the phenotypic breadth of clinical SAVI manifestations. Given the therapeutic benefit of treatment with JAK inhibitors, early genetic testing for SAVI should be considered in patients with unclear systemic inflammation involving cutaneous, pulmonary, or musculoskeletal symptoms, and signs of immunodeficiency and autoimmunity.

Deficiency of Trex1 leads to spontaneous development of type 1 diabetes

BACKGROUND

Type 1 diabetes is believed to be an autoimmune condition, characterized by destruction of insulin-producing cells, due to the detrimental inflammation in pancreas. Growing evidences have indicated the important role of type I interferon in the development of type 1 diabetes.

METHODS

Trex1-deficient rats were generated by using CRISPR-Cas9. The fasting blood glucose level of rat was measured by a Roche Accuchek blood glucose monitor. The levels of insulin, islet autoantibodies, and interferon-β were measured using enzyme-linked immunosorbent assay. The inflammatory genes were detected by quantitative PCR and RNA-seq. Hematein-eosin staining was used to detect the pathological changes in pancreas, eye and kidney. The pathological features of kidney were also detected by Masson trichrome and periodic acid-Schiff staining. The distribution of islet cells, immune cells or ssDNA in pancreas was analyzed by immunofluorescent staining.

RESULTS

In this study, we established a Trex1-deletion Sprague Dawley rat model, and unexpectedly, we found that the Trex1-/- rats spontaneously develop type 1 diabetes. Similar to human diabetes, the hyperglycemia in rats is accompanied by diabetic complications such as diabetic nephropathy and cataract. Mechanistical investigation revealed the accumulation of ssDNA and the excessive production of proinflammatory cytokines, including IFN-β, in Trex1 null pancreas. These are likely contributing to the inflammation in pancreas and eventually leading to the decline of pancreatic β cells.

CONCLUSIONS

Our study links the DNA-induced chronic inflammation to the pathogenesis of type 1 diabetes, and also provides an animal model for type 1 diabetes studies.

Platelets are a major player and represent a therapeutic opportunity in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune dysregulation and organ injury with a premature mortality due to cardiovascular diseases. Platelets, that are primarily known for their role in hemostasis, have been shown to play an active role in the pathogenesis and in the progression of immune-mediated inflammatory diseases. Here we summarize the evidence of their roles in SLE pathogenesis which supports the development of targeted treatments. Platelets and their precursors, the megakaryocytes, are intrinsically different in SLE patients compared with healthy controls. Different triggers related to innate and adaptive immunity activate platelets which release extracellular vesicles, soluble factors and interact with immune cells, thereby perpetuating inflammation. Platelets are involved in organ damage in SLE, especially in lupus nephritis and participate in the heightened cardiovascular mortality. They also play a clear role in antiphospholipid syndrome which can be associated with both thrombocytopenia and thrombosis. To tackle platelet activation and their interactions with immune cells now constitute promising therapeutic strategies in SLE.

The crucial regulatory role of type I interferon in inflammatory diseases

Type I interferon (IFN-I) plays crucial roles in the regulation of inflammation and it is associated with various inflammatory diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and periodontitis, impacting people's health and quality of life. It is well-established that IFN-Is affect immune responses and inflammatory factors by regulating some signaling. However, currently, there is no comprehensive overview of the crucial regulatory role of IFN-I in distinctive pathways as well as associated inflammatory diseases. This review aims to provide a narrative of the involvement of IFN-I in different signaling pathways, mainly mediating the related key factors with specific targets in the pathways and signaling cascades to influence the progression of inflammatory diseases. As such, we suggested that IFN-Is induce inflammatory regulation through the stimulation of certain factors in signaling pathways, which displays possible efficient treatment methods and provides a reference for the precise control of inflammatory diseases.

Glabridin improves autoimmune disease in Trex1-deficient mice by reducing type I interferon production

BACKGROUND

The cGAS-STING signaling pathway is an essential section of the natural immune system. In recent years, an increasing number of studies have shown a strong link between abnormal activation of the cGAS-STING signaling pathway, a natural immune pathway mediated by the nucleic acid receptor cGAS, and the development and progression of autoimmune diseases. Therefore, it is important to identify an effective compound to specifically downregulate this pathway for disease.

METHODS

The effect of Glabridin (Glab) was investigated in BMDMs and Peripheral blood mononuclear cell (PBMC) by establishing an in vitro model of cGAS-STING signaling pathway activation. An activation model stimulated by DMXAA was also established in mice to study the effect of Glab. On the other hand, we investigated the possible mechanism of action of Glab and the effect of Glab on Trex1-deficient mice.

RESULTS

In this research, we report that Glab, a major component of licorice, specifically inhibits the cGAS-STING signaling pathway by inhibiting the level of type I interferon and inflammatory cytokines (IL-6 and TNF-α). In addition, Glab has a therapeutic effect on innate immune diseases caused by abnormal cytoplasmic DNA in Trex1-deficient mice. Mechanistically, Glab can specifically inhibit the interaction of STING with IRF3.

CONCLUSION

Glab is a specific inhibitor of the cGAS-STING signaling pathway and may be used in the clinical therapy of cGAS-STING pathway-mediated autoimmune diseases.

Imatinib and M351-0056 enhance the function of VISTA and ameliorate the development of SLE via IFN-I and noncanonical NF-κB pathway

V-domain immunoglobulin suppressor of T-cell activation (VISTA), an important negative checkpoint protein, participates in immunoregulation. Systemic lupus erythematosus (SLE) is an autoimmune disease in which patients exhibit high levels of autoantibodies and multi-organ tissue injury, primarily involving the kidney and skin. In wild-type (WT) mice and Vsir-/- mice with pristane-induced lupus-like disease, we found that VISTA deficiency exacerbated the lupus-like disease in mice, possibly through aberrant activation of type I interferon (IFN-I) signaling, CD4+ T cell, and noncanonical nuclear factor-κB (NF-κB) pathway. Surface plasmon resonance results showed that imatinib, an FDA-approved tyrosine kinase inhibitor, may have a high affinity for human VISTA-ECD with a KD value of 0.2009 μM. The biological activities of imatinib and VISTA agonist M351-0056 were studied in monocytes and T cells and in lupus-like disease murine model of chronic graft-versus-host disease (cGVHD) and lupus-prone MRL/lpr mice. VISTA small-molecule agonist reduced the cytokine production of peripheral blood mononuclear cells (PBMCs) and Jurkat cells and inhibited PBMCs proliferation. Moreover, they attenuated the levels of autoantibodies, renal injury, inflammatory cytokines, chemokines, and immune cell expansion in the cGVHD mouse model and MRL/lpr mice. Our findings also demonstrated that VISTA small-molecule agonist ameliorated the development of SLE through improving aberrantly activated IFN-I signaling and noncanonical NF-κB pathway. In conclusion, VISTA has a protective effect on the development and progression of SLE. VISTA agonist M351-0056 and imatinib have been firstly demonstrated to attenuate SLE, suggesting interventions to enhance VISTA function may be effective in treating SLE. VISTA deficiency exacerbates pristane-induced lupus-like disease in mice by promoting activation of the IFN-I and noncanonical NF-κB pathway. Imatinib was screened as a small-molecule VISTA agonist by molecular docking, SPR, and cellular level experiments. VISTA agonists (M351-0056 and imatinib) alleviated lupus-like disease progression in the cGVHD mouse model and MRL/lpr mice by inhibiting activation of IFN-I and noncanonical NF-κB pathway.

Differences and similarities in cytokine profiles of macrophage activation syndrome in systemic lupus erythematosus and adult-onset Still's disease

To clarify the differences and similarities in the cytokine profiles of macrophage activating syndrome (MAS) between systemic lupus erythematosus (SLE) and adult-onset Still's disease (AOSD). The study participants included 9 patients with MAS-SLE, 22 with non-MAS-SLE, 9 with MAS-AOSD, and 13 with non-MAS-AOSD. Serum cytokine levels were measured using a multiplex bead assay. Cytokine levels were compared between patients with SLE and AOSD with/without MAS. Moreover, cytokine patterns were examined using principal component analysis (PCA) and cluster analysis. IL-6, IL-8, IL-18, and TNF-α levels were elevated in patients with SLE and AOSD. IFN-α levels were elevated in SLE, whereas IL-1β and IL-18 levels were elevated in AOSD. In SLE, IFN-α and IL-10 levels were higher in MAS than in non-MAS and controls. PCA revealed distinctive cytokine patterns in SLE and AOSD, SLE with IFN-α and IP-10, AOSD with IL-1β, IL-6, and IL-18, and enhanced cytokine production in MAS. PCA and cluster analysis showed no differences in cytokine patterns between the MAS and non-MAS groups. However, serum ferritin levels were correlated with IFN-α levels in SLE. Cytokine profiles differed between SLE and AOSD but not between MAS and non-MAS. MAS is induced by the enhancement of underlying cytokine abnormalities rather than by MAS-specific cytokine profiles. Type I IFN may be involved in MAS development in patients with SLE.

HSPA13 modulates type I interferon antiviral pathway and NLRP3 inflammasome to restrict dengue virus infection in macrophages

Dengue virus (DENV) is a type of arthropod-borne Flavivirus, which leads to a series of serious diseases like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DENV has a devastating health and economic impact worldwide. However, there are no suitable drugs to combat the virus. Here we reported that HSPA13, also known as stress chaperone (STCH), is a member of the HSP70 family and is a key regulator of type I interferon (IFN-I) and pro-inflammatory responses during DENV infection. HSPA13 expression was increased in macrophages infected with DENV or other Flaviviruses like Zika virus (ZIKV), Yellow fever virus (YFV) and Japanese encephalitis virus (JEV). Further, HSPA13 suppressed the replication of DENV and other Flaviviruses (ZIKV, JEV, YFV), which exhibited broad-spectrum antiviral effects. On the one hand, HSPA13 promoted production of IFN-β and interferon-stimulated genes (ISGs, such as ISG15, OAS and IFIT3) by interacting with RIG-I and up-regulating RIG-I expression during DENV infection. On the other hand, HSPA13 enhanced NLRP3 inflammasome activation and IL-1β secretion by interacting with ASC in DENV infection. We identified HSPA13 as a potential anti-DENV target. Our results provide clues for the development of antiviral drugs against DENV based on HSPA13 and reveal novel drug target against Flaviviruses.

Nascent transcription upon interferon-α2 stimulation on human and rhesus macaque lymphoblastoid cell lines

OBJECTIVES

The interferon-triggered innate immune response has been observed to be under strong diversifying selection to counteract the many pathogens hosts have to defend against. In particular, rewiring of gene transcription regulation allows organisms to rapidly acquire new phenotypes by removing and adding genes into the innate immune gene network. Dissecting the molecular processes by which this rewiring takes place, either by changing the DNA regulatory elements or by changing the activity of the regulators across species, is key to better understand this evolutionary process.

DATA DESCRIPTION

To better comprehend the evolutionary dynamics that have occurred in the initial transcriptional response to interferon in primates, we present Precision Run-On (PRO-seq) datasets made after 1 h of interferon-α2 stimulation on human and rhesus macaque lymphoblastoid cell lines. Further, we tested the difference between using either species' cognate interferon versus using the other orthologous interferon to account for any potential impacts in the interaction of the orthologous interferons with their cellular membrane receptors. This data provides insights into the regulatory mechanisms that drive species-specific responses to environmental perturbations, such as the one driven by the interactions of pathogens and their hosts.

Tumor microenvironment-responsive DNA-based nanomedicine triggers innate sensing for enhanced immunotherapy

Lack of proper innate sensing inside the tumor microenvironment could reduce both innate and adaptive immunity, which remains a critical cause of immunotherapy failure in various tumor treatments. Double-stranded DNA (dsDNA) has been evidenced to be a promising immunostimulatory agent to induce type I interferons (IFN-Is) production for innate immunity activation through the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway, yet the unsatisfactory delivery and susceptibility to nuclease degradation hindered its feasibility for further clinical applications. Herein, we report on the constructed tumor microenvironment-responsive DNA-based nanomedicine loaded by dendritic mesoporous organosilica nanoparticles (DMONs), which provide efficient delivery of dsDNA to induce intratumoral IFN-Is production for triggering innate sensing for enhanced anti-tumor immunotherapy. Extensive in vitro and in vivo evaluations have demonstrated the dramatic IFN-Is production induced by dsDNA@DMONs in both immune cells and tumor cells, which facilitates dendritic cells (DCs) maturation and T cells activation for eliciting the potent innate immune and adaptive immune responses. Desirable biosafety and marked therapeutic efficacy with a tumor growth inhibition (TGI) of 51.0% on the murine B16-F10 melanoma model were achieved by the single agent dsDNA@DMONs. Moreover, dsDNA@DMONs combined with anti-PD-L1 antibody further enhanced the anti-tumor efficacy and led to almost complete tumor regression. Therefore, this work highlighted the immunostimulatory DNA-based nanomedicine as a promising strategy for overcoming the resistance to immunotherapy, by promoting the IFN-Is production for innate immunity activation and remodeling the tumor microenvironment.

Low-dose metronomic chemotherapy triggers oxidized mtDNA sensing inside tumor cells to potentiate CD8+T anti-tumor immunity

Low-dose metronomic (LDM) chemotherapy, the frequent and continuous use of low doses of conventional chemotherapeutics, is emerging as a promising form of chemotherapy utilization. LDM chemotherapy exerts immunomodulatory effects. However, the underlying mechanism is not fully understood. Here we found that suppressing tumor growth by LDM chemotherapy was dependent on the activation of CD8+T cells. LDM chemotherapy potentiated the cytotoxic function of CD8+T cells by stimulating cancer-cell autonomous type I interferon (IFN) induction. Mechanistically, LDM chemotherapy evoked mitochondrial dysfunction and increased reactive oxygen species (ROS) production. ROS triggered the oxidation of cytosolic mtDNA, which was sensed by cGAS-STING, consequently inducing type I IFN production in the cancer cells. Moreover, the cGAS-STING-IFN axis increased PD-L1 expression and predicted favorable clinical responses to chemoimmunotherapy. Antioxidant N-acetylcysteine inhibited oxidized mtDNA-induced type I IFN production and attenuated the efficacy of combination therapy with LDM chemotherapy and PD-L1 blockade. This study elucidates the critical role of intratumoral oxidized mtDNA sensing in LDM chemotherapy-mediated activation of CD8+T cell immune response. These findings may provide new insights for designing combinatorial immunotherapy for cancer patients.

Mitochondrial Lon protease promotes CD4+ T cell activation by activating the cGAS-STING-TBK1 axis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which autoreactive CD4+ T cells play an essential role. We extracted CD4+ T cells from SLE-prone Fcgr2b-/- mice to elaborate the mechanism of mitochondrial Lon protease in CD4+ T cell activation in SLE. Transcriptome sequencing was performed in SLE-prone Fcgr2b-/- mice, and the stimulator of interferon gene (STING) related to SLE was obtained. It was demonstrated that STING expression was elevated in CD4+ T cells in SLE-prone Fcgr2b-/- mice. The downstream genes and pathways of STING were predicted by GO and KEGG approaches. The data indicated that STING regulated IFN signaling to promote CD4+ T cell activation in SLE-prone Fcgr2b-/- mice. Next, the interaction of cGAS, STING, TBK1, and IFN-I was verified by Co-IP assay. Moreover, the roles of cGAS, STING, and TBK1 in activating CD4+ T cells from SLE-prone Fcgr2b-/- mice were evaluated using gain- or loss-of-function experiments. Mechanistically, cGAS upregulated the IFN-I signaling pathway by directly interacting with STING and TBK1, contributing to CD4+ T cell activation. Besides, cytosolic mtDNA could activate CD4+ T cell activation in SLE-prone Fcgr2b-/- mice by upregulating the cGAS-STING-TBK1 axis. The function of mitochondrial Lon protease in oxidative damage and mtDNA release in CD4+ T cells of SLE-prone Fcgr2b-/- mice were explored. Mitochondrial Lon protease enhanced mtDNA release into the cytoplasm under oxidative stress. Collectively, our work indicates that mitochondrial Lon protease enhances CD4+ T cell activation by inducing mtDNA leakage and offers new candidate targets for developing diagnostic and therapeutic strategies.

Astrocytes evoke a robust IRF7-independent type I interferon response upon neurotropic viral infection

BACKGROUND

Type I interferons (IFN-I) are fundamental in controlling viral infections but fatal interferonopathy is restricted in the immune-privileged central nervous system (CNS). In contrast to the well-established role of Interferon Regulatory Factor 7 (IRF7) in the regulation of IFN-I response in the periphery, little is known about the specific function in the CNS.

METHODS

To investigate the role for IRF7 in antiviral response during neurotropic virus infection, mice deficient for IRF3 and IRF7 were infected systemically with Langat virus (LGTV). Viral burden and IFN-I response was analyzed in the periphery and the CNS by focus formation assay, RT-PCR, immunohistochemistry and in vivo imaging. Microglia and infiltration of CNS-infiltration of immune cells were characterized by flow cytometry.

RESULTS

Here, we demonstrate that during infection with the neurotropic Langat virus (LGTV), an attenuated member of the tick-borne encephalitis virus (TBEV) subgroup, neurons do not rely on IRF7 for cell-intrinsic antiviral resistance and IFN-I induction. An increased viral replication in IRF7-deficient mice suggests an indirect antiviral mechanism. Astrocytes rely on IRF7 to establish a cell-autonomous antiviral response. Notably, the loss of IRF7 particularly in astrocytes resulted in a high IFN-I production. Sustained production of IFN-I in astrocytes is independent of an IRF7-mediated positive feedback loop.

CONCLUSION

IFN-I induction in the CNS is profoundly regulated in a cell type-specific fashion.

Disruption of type I interferon pathway and reduced production of IFN-α by parabens in virus-infected dendritic cells

BACKGROUND

Parabens are widely used preservatives commonly found in foods, cosmetics, and industrial products. Several studies have examined the effects of parabens on human health owing to widespread and continuous exposure to them in daily life. However, little is known about their immune-regulatory effects.

OBJECTIVE

Here, we aimed to investigate whether methylparaben, ethylparaben, and propylparaben affect the function of dendritic cells (DCs) as the most potent antigen-presenting cells that play a critical role in the initiation of adaptive immune responses.

METHODS

Bone-marrow derived DCs (BMDCs) were treated with three types of parabens (methylparaben, ethylparaben, and propylparaben) for 12 h. Subsequently, the transcriptomic profile was analyzed using RNA sequencing with further gene set enrichment analysis based on commonly regulated differentially expressed genes (DEGs). To test whether parabens suppress the production of type-I interferons (IFN-I) in BMDCs during viral infection, BMDCs or paraben-treated BMDCs were infected with Lymphocytic Choriomeningitis Virus (LCMV) at 10 multiplicity of infection (MOI) and measured the production of IFN-α1.

RESULTS

Transcriptomic analyses revealed that all three types of parabens reduced the transcription levels of genes in virus infection-associated pathways, such as IFN-I responses in BMDCs. Furthermore, parabens considerably reduced IFN-α1 production in the virus-infected BMDCs.

CONCLUSION

Our study is the first to show that parabens may modulate anti-viral immune responses by regulating DCs.

Ceragenins exhibit antiviral activity against SARS-CoV-2 by increasing the expression and release of type I interferons upon activation of the host's immune response

The COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) heavily burdened the entire world socially and economically. Despite a generation of vaccines and therapeutics to confront infection, it remains a threat. Most available antivirals target viral proteins and block their activity or function. While such an approach is considered effective and safe, finding treatments for specific viruses of concern leaves us unprepared for developed resistance and future viral pandemics of unknown origin. Here, we propose ceragenins (CSAs), synthetic amphipathic molecules designed to mimic the properties of cationic antimicrobial peptides (cAMPs), as potential broad-spectrum antivirals. We show that selected CSAs exhibit antiviral activity against SARS-CoV-2 and low-pathogenic human coronaviruses 229E, OC43, and NL63. The mechanism of action of CSAs against coronaviruses is mainly attributed to the stimulation of antiviral cytokines, such as type I interferons or IL-6. Our study provides insight into a novel immunomodulatory strategy that might play an essential role during the current pandemic and future outbreaks.

Mitochondrial dysfunction and type I interferon signaling induce anxiodepressive-like behaviors in mice with neuropathic pain

Clinical evidence indicates that major depression is a common comorbidity of chronic pain, including neuropathic pain; however, the cellular basis for chronic pain-mediated major depression remains unclear. Mitochondrial dysfunction induces neuroinflammation and has been implicated in various neurological diseases, including depression. Nevertheless, the relationship between mitochondrial dysfunction and anxiodepressive-like behaviors in the neuropathic pain state remains unclear. The current study examined whether hippocampal mitochondrial dysfunction and downstream neuroinflammation are involved in anxiodepressive-like behaviors in mice with neuropathic pain, which was induced by partial sciatic nerve ligation (PSNL). At 8 weeks after surgery, there was decreased levels of mitochondrial damage-associated molecular patterns, such as cytochrome c and mitochondrial transcription factor A, and increased level of cytosolic mitochondrial DNA in the contralateral hippocampus, suggesting the development of mitochondrial dysfunction. Type I interferon (IFN) mRNA expression in the hippocampus was also increased at 8 weeks after PSNL surgery. The restoration of mitochondrial function by curcumin blocked the increased cytosolic mitochondrial DNA and type I IFN expression in PSNL mice and improved anxiodepressive-like behaviors. Blockade of type I IFN signaling by anti-IFN alpha/beta receptor 1 antibody also improved anxiodepressive-like behaviors in PSNL mice. Together, these findings suggest that neuropathic pain induces hippocampal mitochondrial dysfunction followed by neuroinflammation, which may contribute to anxiodepressive-behaviors in the neuropathic pain state. Improving mitochondrial dysfunction and inhibiting type I IFN signaling in the hippocampus might be a novel approach to reducing comorbidities associated with neuropathic pain, such as depression and anxiety.

Live Mycobacterium paragordonae induces heterologous immunity of natural killer cells by eliciting type I interferons from dendritic cells via STING-dependent sensing of cyclic-di-GMP

Exploiting the heterologous effects of vaccines is a feasible strategy to combat different pathogens. These effects have been explained by enhanced immune responses of innate immune cells. Mycobacterium paragordonae is a rare nontuberculosis mycobacterium that has temperature-sensitive properties. Although natural killer (NK) cells exhibit heterologous immunity features, the cellular crosstalk between NK cells and dendritic cells (DCs) during live mycobacterial infection has remained elusive. We show that live but not dead M. paragordonae enhances heterologous immunity against unrelated pathogens in NK cells by IFN-β of DCs in both mouse models and primary human immune cells. C-di-GMP from live M. paragordonae acted as a viability-associated pathogen-associated molecular pattern (Vita-PAMP), leading to STING-dependent type I IFN production in DCs via the IRE1α/XBP1s pathway. Also, increased cytosolic 2'3'-cGAMP by cGAS can induce type I IFN response in DCs by live M. paragordonae infection. We found that DC-derived IFN-β plays a pivotal role in NK cell activation by live M. paragordonae infection, showing NK cell-mediated nonspecific protective effects against Candida albicans infection in a mouse model. Our findings indicate that the heterologous effect of live M. paragordonae vaccination is mediated by NK cells based on the crosstalk between DCs and NK cells.

MicroRNA-9-1 Attenuates Influenza A Virus Replication via Targeting Tankyrase 1

An unstable influenza genome leads to the virus resistance to antiviral drugs that target viral proteins. Thus, identification of host factors essential for virus replication may pave the way to develop novel antiviral therapies. In this study, we investigated the roles of the poly(ADP-ribose) polymerase enzyme, tankyrase 1 (TNKS1), and the endogenous small noncoding RNA, miR-9-1, in influenza A virus (IAV) infection. Increased expression of TNKS1 was observed in IAV-infected human lung epithelial cells and mouse lungs. TNKS1 knockdown by RNA interference repressed influenza viral replication. A screen using TNKS1 3'-untranslation region (3'-UTR) reporter assays and predicted microRNAs identified that miR-9-1 targeted TNKS1. Overexpression of miR-9-1 reduced influenza viral replication in lung epithelial cells as measured by viral mRNA and protein levels as well as virus production. miR-9-1 induced type I interferon production and enhanced the phosphorylation of STAT1 in cell culture. The ectopic expression of miR-9-1 in the lungs of mice by using an adenoviral viral vector enhanced type I interferon response, inhibited viral replication, and reduced susceptibility to IAV infection. Our results indicate that miR-9-1 is an anti-influenza microRNA that targets TNKS1 and enhances cellular antiviral state.

Selective neuroimmune modulation by type I interferon drives neuropathology and neurologic dysfunction following traumatic brain injury

Accumulating evidence suggests that type I interferon (IFN-I) signaling is a key contributor to immune cell-mediated neuropathology in neurodegenerative diseases. Recently, we demonstrated a robust upregulation of type I interferon-stimulated genes in microglia and astrocytes following experimental traumatic brain injury (TBI). The specific molecular and cellular mechanisms by which IFN-I signaling impacts the neuroimmune response and neuropathology following TBI remains unknown. Using the lateral fluid percussion injury model (FPI) in adult male mice, we demonstrated that IFN α/β receptor (IFNAR) deficiency resulted in selective and sustained blockade of type I interferon-stimulated genes following TBI as well as decreased microgliosis and monocyte infiltration. Molecular alteration of reactive microglia also occurred with diminished expression of genes needed for MHC class I antigen processing and presentation following TBI. This was associated with decreased accumulation of cytotoxic T cells in the brain. The IFNAR-dependent modulation of the neuroimmune response was accompanied by protection from secondary neuronal death, white matter disruption, and neurobehavioral dysfunction. These data support further efforts to leverage the IFN-I pathway for novel, targeted therapy of TBI.

Plasmacytoid dendritic cells: A dendritic cell in disguise

Since their discovery, the identity of plasmacytoid dendritic cells (pDCs) has been at the center of a continuous dispute in the field, and their classification as dendritic cells (DCs) has been recently re-challenged. pDCs are different enough from the rest of the DC family members to be considered a lineage of cells on their own. Unlike the exclusive myeloid ontogeny of cDCs, pDCs may have dual origin developing from myeloid and lymphoid progenitors. Moreover, pDCs have the unique ability to quickly secrete abundant levels of type I interferon (IFN-I) in response to viral infections. In addition, pDCs undergo a differentiation process after pathogen recognition that allows them to activate T cells, a feature that has been shown to be independent of presumed contaminating cells. Here, we aim to provide an overview of the historic and current understanding of pDCs and argue that their classification as either lymphoid or myeloid may be an oversimplification. Instead, we propose that the capacity of pDCs to link the innate and adaptive immune response by directly sensing pathogens and activating adaptive immune responses justify their inclusion within the DC network.

Strategies involving STING pathway activation for cancer immunotherapy: Mechanism and agonists

Recent studies have expanded the known functions of cGAS-STING in inflammation to a role in cancer due to its participation in activating immune surveillance. In cancer cells, the cGAS-STING pathway can be activated by cytosolic dsDNA derived from genomic, mitochondrial and exogenous origins. The resulting immune-stimulatory factors from this cascade can either attenuate tumor growth or recruit immune cells for tumor clearance. Furthermore, STING-IRF3-induced type I interferon signaling can enforce tumor antigen presentation on dendritic cells and macrophages and thus cross-prime CD8+ T cells for antitumor immunity. Given the functions of the STING pathway in antitumor immunity, multiple strategies are being developed and tested with the rationale of activating STING in tumor cells or tumor-infiltrating immune cells to elicit immunostimulatory effects, either alone or in combination with a range of established chemotherapeutic and immunotherapeutic regimens. Based on the canonical molecular mechanism of STING activation, numerous strategies for inducing mitochondrial and nuclear dsDNA release have been used to activate the cGAS-STING signaling pathway. Other noncanonical strategies that activate cGAS-STING signaling, including the use of direct STING agonists and STING trafficking facilitation, also show promise in type I interferon release and antitumor immunity priming. Here, we review the key roles of the STING pathway in different steps of the cancer-immunity cycle and characterize the canonical and noncanonical mechanisms of cGAS-STING pathway activation to understand the potential of cGAS-STING agonists for cancer immunotherapy.

Mutations in the non-structural protein coding region regulate gene expression from replicon RNAs derived from Venezuelan equine encephalitis virus

Self-replicating RNA (repRNA) derived from Venezuelan equine encephalitis (VEE) virus is a promising platform for gene therapy and confers prolonged gene expression due to its self-replicating capability, but repRNA suffers from a suboptimal transgene expression level due to its induction of intracellular innate response which may result in inhibition of translation. To improve transgene expression of repRNA, we introduced point mutations in the non-structural protein 1-4 (nsP1-4) coding region of VEE replicon vectors. As a proof of concept, inflammatory cytokines served as genes of interest and were cloned in their wild type and several mutant replicon vectors, followed by transfection in mammalian cells. Our data show that VEE replicons bearing nsP1GGAC-nsP2T or nsP1GGAC-nsP2AT mutations in the nsP1-4 coding region could significantly reduce the recognition by innate immunity as evidenced by the decreased production of type I interferon, and enhance transgene expression in host cells. Thus, the newly discovered mutant VEE replicon vectors could serve as promising gene expression platforms to advance VEE-derived repRNA-based gene therapies.

STING controls opioid-induced itch and chronic itch via spinal tank-binding kinase 1-dependent type I interferon response in mice

BACKGROUND

Patients receiving epidural or intrathecal opioids administration for neuraxial analgesia frequently suffer from an irritating itch. STING (stimulator of interferon genes), an innate immune modulator, is strongly implicated in pain pathogenesis via neuron-immune modulation. Given that pain and itch share some common neurocircuits, we evaluate the therapeutic potential of STING agonists in opioid-induced itch and chronic itch.

METHODS

Opioids (morphine, fentanyl and sufentanil) were intrathecally injected to induce acute itch. Chronic itch was induced by dry skin and contact dermatitis. Opioids analgesic effect, itch-induced scratching behavior, spinal expression of STING, phosphorylation of TBK1 (tank-binding kinase 1), IRF3 (interferon regulatory factor-3) and ERK (extracellular signal-regulated kinase), as well as production of IFN-α and IFN-β were examined. STING agonists (DMXAA and ADU-S100), TBK1 inhibitor, recombinant IFN-α and IFN-β elucidated the mechanism and treatment of itch. Whole-brain functional connectivity was evaluated using resting-state fMRI.

RESULTS

We report the primary expression of STING protein by the spinal dorsal horn neurons. Intraperitoneal injection of DMXAA dose-dependently reduces morphine-induced scratch bouts, without impairing morphine antinociception. Simultaneously, DMXAA alleviates fentanyl- and sufentanil-induced itching-like behavior, and chronic scratching behavior caused by dry skin and contact dermatitis. Furthermore, DMXAA drastically increases spinal phosphorylation of TBK1 and IRF3 following morphine exposure, dry skin and contact dermatitis. DMXAA-induced anti-pruritus effects and spinal productions of IFN-α and IFN-β are compensated by intrathecal delivery of the TBK1 inhibitor. Also, ADU-S100, recombinant IFN-α and IFN-β exhibits remarkable attenuation in scratching behaviors after morphine injection and dermatitis. Recombinant IFN-α inhibits morphine-induced spinal phosphorylation of ERK. Finally, DMXAA prevents dermatitis-induced the increase of cerebral functional connectivity between regions of interests such as primary somatosensory cortex, piriform cortex, retrosplenial cortex, colliculus and ventral thalamus.

CONCLUSIONS

STING activation confers protection against opioid-induced itch and chronic itch through spinal up-regulation of TBK1-IRF3-type I interferon cascades in mice, suggesting that STING agonists are promising candidates in translational development for pruritus relief.

CD169 expression on monocytes as a marker for assessing type I interferon status in pediatric inflammatory diseases

BACKGROUND

Evaluation of type I interferons (IFNs) in inflammatory or autoimmune diseases is challenging because of their rapid clearance in peripheral blood. The IFN gene expression signature has recently been used to evaluate the IFN status; however, this is often a labor-intensive and time-consuming procedure. Therefore, we assessed the feasibility of measuring expression of an IFN-inducible protein, CD169 (Siglec-1), on monocytes and circulating levels of soluble CD169 as alternative markers for type I IFN status in various pediatric inflammatory diseases.

METHODS

Data from flow cytometric analysis of surface CD169 on monocytes and an enzyme-linked immunosorbent assay of soluble CD169 in peripheral blood were compared with serum IFN-α levels in 8 patients with viral infections, 5 with bacterial infections, 10 with systemic lupus erythematosus (SLE), 5 with Kikuchi-Fujimoto disease (KFD), 7 with Kawasaki disease (KD), and 8 with inflammatory bowel disease (IBD), and in 8 healthy controls.

RESULTS

Surface CD169 expression was detected mainly on CD14⁺ monocytes and was significantly increased in patients with viral infections, SLE, and KFD, but not in patients with bacterial infections, KD, and IBD. There were similar trends for circulating soluble CD169; however, there was a significant increase only in patients with viral infections. Surface CD169 levels were significantly correlated with serum levels of IFN-α and soluble CD169.

CONCLUSION

Analysis of CD169 expression on CD14⁺ monocytes may be useful for rapid assessment of type I IFN status for differentiation of pediatric inflammatory diseases from type 1 IFN-mediated diseases.

Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

BACKGROUND

We previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in ~ 80% of cases.

METHODS

We report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded.

RESULTS

No gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P = 1.1 × 10-4) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR = 3.70[95%CI 1.3-8.2], P = 2.1 × 10-4). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR = 19.65[95%CI 2.1-2635.4], P = 3.4 × 10-3), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR = 4.40[9%CI 2.3-8.4], P = 7.7 × 10-8). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD] = 43.3 [20.3] years) than the other patients (56.0 [17.3] years; P = 1.68 × 10-5).

CONCLUSIONS

Rare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old.

Immunomodulatory effects of targeted radionuclide therapy

It is now clear that conventional radiation therapy can reinstate cell death immunogenicity. Recent preclinical data indicate that targeted radionuclide therapy that irradiate tumors at continuous low dose rate also can elicit immunostimulatory effects and represents a promising strategy to circumvent immune checkpoint inhibitor resistance. In this perspective, we discuss the accumulating preclinical and clinical data suggesting that activation of the immune system through the cGAS-STING axis and the release of extracellular vesicles by irradiated cells, participate to this antitumor immunity. This should need to be considered for adapting clinical practices to state of the art of the radiobiology and to increase targeted radionuclide therapy effectiveness.

p120-catenin promotes innate antiviral immunity through stabilizing TBK1-IRF3 complex

TBK1-IRF3 complex plays vital roles in antiviral immune responses, its regulatory mechanisms are currently incompletely understood. p120-catenin (p120), an armadillo-repeat protein, mainly regulates the stability of classical cadherins and the development of epithelial-to-mesenchymal transitions (EMTs). Here we report that p120 is a positive regulator of type I IFN production. Ectopic expression of p120 enhanced Vesicular stomatitis virus and Sendai-virus-induced type I IFN production, whereas knockdown of p120 expression suppressed type I IFN production. Mechanistically, p120 promoted phosphorylation of IRF3 via stabilizing the TBK1-IRF3 complex. Consistently, p120 knock down mice are more susceptible to VSV infection as indicated by higher tissue viral titers, less IFN-I production and greater infiltration of immune cells. This study reveals p120 as an important positive regulator in innate immunity and identifies that p120 facilitates host antiviral response through stabilizing TBK1-IRF3 complex.

Size-optimized nuclear-targeting phototherapy enhances the type I interferon response for "cold" tumor immunotherapy

There is growing interest in the effect of innate immune silencing in "cold" tumors, which always fail in the immune checkpoint blockade monotherapy using PD-L1 monoclonal antibodies (aPD-L1). Combination of aPD-L1 with photodynamic therapy, i.e., photoimmunotherapy, is a promising strategy to improve the mono immunotherapy. Nuclear-targeting nanoparticles could elicit a type I interferon (IFN)-mediated innate immune response and reverse the immunosuppressive microenvironment for long-term immunotherapy of "cold" tumors. Photosensitizers such as zinc phthalocyanine (ZnPc) have limited ability to target the nucleus and activate innate sensing pathways to minimize tumor recurrence. Additionally, the relationship between nanoparticle size and nuclear entry capacity remains unclear. Herein, graphene quantum dots (GQDs) were employed as aPD-L1 and ZnPc carriers. Three particle sizes (200 nm, 32 nm and 5 nm) of aPD-L1/ZnPc/GQD-PEG (PZGE) were synthesized and tested. The 5 nm nanoparticles achieved the best nuclear enrichment capacity contributing to their ultrasmall size. Notably, 5 nm PZGE-based photodynamic therapy enabled an amplification of the type I IFN-mediated innate immune response and could convert "immune-cold" tumors into "immune-hot" ones. Utilizing their size advantage to target the nucleus, 5 nm nanoparticles induced DNA damage and activated the type I IFN-mediated innate immune response, subsequently promoting cytotoxic T-lymphocyte infiltration and reversing negative PD-L1 expression. Furthermore, the nanoplatform we designed is promising for the effective suppression of distant oral squamous cell carcinoma. Thus, for the first time, this study presents a size design strategy for nuclear-targeted photo-controlled immune adjuvants and the nuclear-targeted phototherapy-mediated immunomodulatory functions of type I IFN innate immune signalling for "immune-cold" tumors. STATEMENT OF SIGNIFICANCE: The potential of commonly used photosensitizers to activate innate sensing pathways for producing type I IFNs is limited due to the lack of nuclear targeting. Facilitating the nuclear-targeting of photosensitizers to enhance innate immune response and execute long-term tumor killing effect would be a promising strategy for "cold" tumor photoimmunotherapy. Herein, we report an optimal size of PZGE nanoparticles that enable the nuclear-targeting of ZnPc, which reinforces the type I IFN-mediated innate immune response, synergistically reversing "cold tumors" to "hot tumors" for effective primary and distant tumor photoimmunotherapy. This work highlights the marked efficacy of ultrasmall nuclear-located nanocarriers and offers new insight into "immune-cold tumors" via prominent innate immune activation mediated by nuclear-targeting photoimmunotherapy.

Type I and III interferons are good markers to monitor COVID-19 pathophysiology

The COVID-19 pandemic has caused millions of deaths and has resulted in disastrous societal and economic impacts worldwide. During SARS-CoV-2 infection, abnormal levels of pro-inflammatory cytokines have been observed and were associated to the severity of the disease. Type I (-α/β) and Type III (IFN-λ) interferons are family members of cytokines that play an important role in fighting viral replication during the early phases of infection. The location and timing of the IFNs production have been shown to be decisive for the COVID-19 outcome. Despite the effectiveness of COVID-19 vaccines and with the emergence of new SARS-CoV-2 variants, a better understanding of the involvement of IFNs as players in antiviral immunity in the COVID-19 pathophysiology is necessary to implement additional potent prophylactic and/or therapeutic approaches. In this study, we investigated the role of type I and III IFN in COVID-19 pathophysiology. We first analyzed the IFN-α, IFN-β and IFN- λ mRNA expression in nasopharyngeal swabs and blood samples from Moroccan patients infected with SARS-CoV-2 and secondly correlated these IFNs expressions with COVID-19 clinical and biological parameters. Our results showed that in the upper airways of patients with mild, non-severe, or severe COVID-19 manifestations, the IFN- α, - β and - λ are expressed in the same manner as in controls. However, in blood samples their expression was downregulated in all groups. Univariate linear models with interferons as predictors to evaluate clinical-biological parameters highlighted that the main clinical-biological relations were found when testing: FiO2, Lymphocyte values and virus load. Furthermore, the multivariate models confirmed that quantifications of interferons during COVID-19 are good biological markers for tracking COVID-19 pathophysiology.

Pterostilbene effectively inhibits influenza A virus infection by promoting the type I interferon production

With the prevalence of novel strains and drug-resistant influenza viruses, there is an urgent need to develop effective and low-toxicity anti-influenza therapeutics. Regulation of the type I interferon antiviral response is considered an attractive therapeutic strategy for viral infection. Pterostilbene, a 3,5-dimethoxy analog of resveratrol, is known for its remarkable pharmacological activity. Here, we found that pterostilbene effectively inhibited influenza A virus infection and mainly affected the late stages of viral replication. A mechanistic study showed that the antiviral activity of pterostilbene might promote the induction of antiviral type I interferon and expression of its downstream interferon-stimulated genes during viral infection. The same effect of pterostilbene was also observed in the condition of polyinosinic-polycytidylic acid (poly I:C) transfection. Further study showed that pterostilbene interacted with influenza non-structural 1 (NS1) protein, inhibited ubiquitination mediated degradation of RIG-I and activated the downstream antiviral pathway, orchestrating an antiviral state against influenza virus in the cell. Taken together, pterostilbene could be a promising anti-influenza agent for future antiviral drug exploitation and compounds with similar structures may provide new options for the development of novel inhibitors against influenza A virus (IAV).

Interferon stimulated gene 15 (ISG15) in cancer: An update

Among the plethora of defense mechanisms which a host elicits after pathogen invasion, type 1 interferons play a central role in regulating the immune system's response. They induce several interferon-stimulated genes (ISGs) which play a diverse role once activated. Over the past few decades, there have been several studies exploring the role of ISGs in cancer and ISG15 is among the most studied for its pro and anti-tumorigenic role. In this review, we aim to provide an update on the recent observations and findings related to ISG15 in cancer. We provide a brief overview about the initial observations and important historical findings which helped scientists understand structure and function of ISG15. We aim to provide an overview of ISG15 in cancer with an emphasis on studies which delve into the molecular mechanism of ISG15 in modulating the tumor microenvironment. Further, the dysregulation of ISG15 in cancer and the molecular mechanisms associated with its pro and anti-tumor roles are discussed in respective cancer types. Finally, we discuss multiple therapeutic applications of ISG15 in current cancer therapy.

Effect of temperature and IRF-9 gene-knockout on dynamics of vRNA, cRNA, and mRNA of viral hemorrhagic septicemia virus (VHSV)

The replication of viral hemorrhagic septicemia virus (VHSV) in appropriate host cells depends on environmental factors and the host cell's immunity. The dynamics of each VHSV RNA strand (vRNA, cRNA, and mRNA) in different conditions can provide a clue on the viral replication strategies, which can be a base for the development of efficient control measures. As VHSV is known to be sensitive to temperature and type I interferon (IFN) responses, in this study, we analyzed the effect of temperature difference (15 °C and 20 °C) and IRF-9 gene knockout on the dynamics of the three VHSV RNA strands in Epithelioma papulosum cyprini (EPC) cells using a strand-specific RT-qPCR. The tagged primers designed in this study successfully worked to quantify the three strands of VHSV. In the results of the temperature effect, the higher speed in viral mRNA transcription and the significantly higher (more than 10 times at 12-36 h) copy number of cRNA at 20 °C compared to those at 15 °C suggested the positive effect of high temperature on VHSV replication. In the results of the IRF-9 gene knockout effect, although IRF-9 gene knockout did not bring a dramatic effect on VHSV replication compared to the temperature effect, the increase of mRNA in IRF-9 KO cells was faster than normal EPC cells, which was reflected in the copy numbers of cRNA and vRNA. The IRF-9 gene knockout effect was not dramatic even in the replication of rVHSV-ΔNV-eGFP that harbors eGFP gene ORF instead of NV gene ORF. These results suggest that VHSV may be highly susceptible to pre-activated type I IFN responses but not highly susceptible to post-infection-mediated type I IFN responses or lowered type I IFN before infection. In both experiments of temperature effect and IRF-9 gene knockout effect, the copy number of cRNA never exceeded the copy number of vRNA at all assay times, suggesting that the binding efficiency of the RNP complex to the 3' end of cRNA might be lower than that to the 3' end of vRNA. Further research is needed to elucidate the regulatory mechanism that limits the amount of cRNA at an appropriate level during VHSV replication.

Promotion of the resistance of human oral epithelial cells to herpes simplex virus type I infection via N6-methyladenosine modification

OBJECTIVE

This study aimed to explore the mechanism behind N6-methyladenosine (m6A) modification of the total ribonucleic acid (RNA) involved in the resistance to herpes simplex virus type I (HSV-1) infection in oral epithelial cells.

METHOD

The variation in m6A modification level on messenger RNA following HSV-1 infection was determined using the RNA dot blot method. The expression levels of alpha-ketoglutarate-dependent dioxygenase lab homolog 5 (ALKBH5) protein and fatty mass and obesity-associated genes (FTO) were determined using real-time fluorescence quantification polymerase chain reaction and the western blot technique, respectively. Next, after suppressing the expression of ALKBH5 or FTO via small interfering RNA, human immortalised oral epithelial cells (HIOECs) were infected with HSV-1, followed by measurement of the viral load or expression level of type I interferon (I-IFN) and interferon-stimulated genes (ISGs).

RESULTS

The m6A modification level was significantly increased following HSV-1 infection of the HIOECs (P < 0.05), while the expression of ALKBH5 and FTO genes was reduced (P < 0.01). Moreover, the suppression of ALKBH5 or FTO increased the production of I-IFN and ISGs during the HSV-1 infection of the HIOECs (P < 0.01), and the viral load was significantly reduced (P < 0.01).

CONCLUSION

During oral HSV-1 infection, the m6A level was increased through the down-regulation of ALBHK5 and FTO expression, increasing I-IFN production and the promotion of HSV-1 clearing in HIOECs.

The induction and suppression of type I and type III interferons by human group H rotavirus

Group H Rotavirus (RVH) is associated with human diarrhea gastroenteritis. The interferon (IFN) response induced by RVH remains unclear. In this study, we first studied the characteristic feature of RVH and found J19 strain of RVH grew less efficiently compared with the G6P1 strain of RVA. Next, we found that infection with the J19 virus resulted in the secretion of IFN-λ1, but not IFN-β, while both IFN-β and IFN-λ1 could inhibit J19 replication significantly in Caco-2 cells. NSP1 played an important role in the suppression of type I and type III IFN response, and NSP5 protein significantly inhibited activation of IFN-λ1. J19 NSP1 suppressed the induction of IFN-β obviously than G6P1 NSP1, while G6P1 NSP1 reduced IFN-λ1 induction to the greatest extent compared with G9P8, Wa, and J19 NSP1s. Our studies reveal the propagation feature of RVH and interferon induction and suppression by group H rotavirus.

Relationship of systemic type I interferon activity with clinical phenotypes, disease activity, and damage accrual in systemic lupus erythematosus in treatment-naive patients: a retrospective longitudinal analysis

BACKGROUND

Systemic lupus erythematosus (SLE) is heterogeneous in organ involvement and disease severity, presenting a broad clinical phenotype. Systemic type I interferon (IFN) activity has been shown to be associated with lupus nephritis, autoantibodies, and disease activity in treated SLE patients; however, these relationships are unknown in treatment-naive patients. We aimed to determine the relationship of systemic IFN activity with clinical phenotypes, disease activity, and damage accrual in treatment-naive SLE patients before and after induction and maintenance therapy.

METHODS

Forty treatment-naive SLE patients were enrolled for this retrospective longitudinal observational study to examine the relationship between serum IFN activity and clinical manifestations of EULAR/ACR-2019 criteria domains, disease activity measures, and damage accrual. As controls, 59 other treatment-naive rheumatic disease patients and 33 healthy individuals were recruited. Serum IFN activity was measured by WISH bioassay and presented as an IFN activity score.

RESULTS

Treatment-naive SLE patients had significantly higher serum IFN activity than other rheumatic disease patients (score: 97.6 and 0.0, respectively, p < 0.001). High serum IFN activity was significantly associated with fever, hematologic disorders (leukopenia), and mucocutaneous manifestations (acute cutaneous lupus and oral ulcer) of EULAR/ACR-2019 criteria domains in treatment-naive SLE patients. Serum IFN activity at baseline significantly correlated with SLEDAI-2K scores and decreased along with a decrease in SLEDAI-2K scores after induction and maintenance therapy (R² = 0.112, p = 0.034). SLE patients who developed organ damage (SDI ≥ 1) had higher serum IFN activity at baseline than those who did not (SDI = 0) (150.0 versus 57.3, p= 0.018), but the multivariate analysis did not detect its independent significance (p = 0.132).

CONCLUSIONS

Serum IFN activity is characteristically high and is linked to fever, hematologic disorders, and mucocutaneous manifestations in treatment-naive SLE patients. Serum IFN activity at baseline correlates with disease activity and decreases in parallel with a decrease in disease activity after induction and maintenance therapy. Our results suggest that IFN plays an important role in the pathophysiology of SLE and that serum IFN activity at baseline may be a potential biomarker for the disease activity in treatment-naive SLE patients.

Lidocaine inhibits influenza a virus replication by up-regulating IFNα4 via TBK1-IRF7 and JNK-AP1 signaling pathways

Influenza A viruses (IAV), significant respiratory pathogenic agents, cause seasonal epidemics and global pandemics in intra- and interannual cycles. Despite effective therapies targeting viral proteins, the continuous generation of drug-resistant IAV strains is challenging. Therefore, exploring novel host-specific antiviral treatment strategies is urgently needed. Here, we found that lidocaine, widely used for local anesthesia and sedation, significantly inhibited H1N1(PR8) replication in macrophages. Interestingly, its antiviral effect did not depend on the inhibition of voltage-gated sodium channels (VGSC), the main target of lidocaine for anesthesia. Lidocaine significantly upregulated early IFN-I, interferon α4 (IFNα4) mRNA, and protein levels, but not those of early IFNβ in mouse RAW 264.7 cell line and human THP-1 derived macrophages. Knocking out IFNα4 by CRISPR-Cas9 partly reversed lidocaine's inhibition of PR8 replication in macrophages. Mechanistically, lidocaine upregulated IFNα4 by activating TANK-binding kinase 1 (TBK1)-IRF7 and JNK-AP1 signaling pathways. These findings indicate that lidocaine has an incredible antiviral potential by enhancing IFN-I signaling in macrophages. In conclusion, our results indicate the potential auxiliary role of lidocaine for anti-influenza A virus therapy and even for anti-SARS-CoV-2 virus therapy, especially in the absence of a specific medicine.

Ste20-Like Kinase TAOK1 Positively Regulates Antiviral Responses by Controlling the TBK1-IRF3 Signaling Axis

The cytosolic viral nucleic acid-sensing pathways converge on the protein kinase TANK-binding kinase 1 (TBK1) and the transcription factor interferon (IFN)-regulatory factor 3 (IRF3) to induce type I IFN production and antiviral immune responses. However, the mechanism that triggers the binding of TBK1 and IRF3 after virus infection remains not fully understood. Here, we identified that thousand and one kinase 1 (TAOK1), a Ste20-like kinase, positively regulated virus-induced antiviral immune responses by controlling the TBK1-IRF3 signaling axis. Virus invasion downregulated the expression of TAOK1. TAOK1 deficiency resulted in decreased nucleic acid-mediated type I IFN production and increased susceptibility to virus infection. TAOK1 was constitutively associated with TBK1 independently of the mitochondrial antiviral signaling protein MAVS. TAOK1 promoted IRF3 activation by enhancing TBK1-IRF3 complex formation. TAOK1 enhanced virus-induced type I IFN production in a kinase activity-dependent manner. Viral infection induced TAOK1 to bind with dynein instead of microtubule-associated protein 4 (MAP4), leading to the trafficking of TBK1 to the perinuclear region to bind IRF3. Thus, the depolymerization of microtubule impaired virus-mediated IRF3 activation. Our results revealed that TAOK1 functioned as a new interaction partner and regulated antiviral signaling via trafficking TBK1 along microtubules to bind IRF3. These findings provided novel insights into the function of TAOK1 in the antiviral innate immune response and its related clinical significance.

Systems analysis of human responses to an aluminium hydroxide-adsorbed TLR7 agonist (AS37) adjuvanted vaccine reveals a dose-dependent and specific activation of the interferon-mediated antiviral response

The candidate Adjuvant System AS37 contains a synthetic toll-like receptor agonist (TLR7a) adsorbed to alum. In a phase I study (NCT02639351), healthy adults were randomised to receive one dose of licensed alum-adjuvanted meningococcal serogroup C (MenC-CRM₁₉₇) conjugate vaccine (control) or MenC-CRM₁₉₇ conjugate vaccine adjuvanted with AS37 (TLR7a dose 12.5, 25, 50 or 100 µg). A subset of 66 participants consented to characterisation of peripheral whole blood transcriptomic responses, systemic cytokine/chemokine responses and multiple myeloid and lymphoid cell responses as exploratory study endpoints. Blood samples were collected pre-vaccination, 6 and 24 h post-vaccination, and 3, 7, 28 and 180 days post-vaccination. The gene expression profile in whole blood showed an early, AS37-specific transcriptome response that peaked at 24 h, increased with TLR7a dose up to 50 µg and generally resolved within one week. Five clusters of differentially expressed genes were identified, including those involved in the interferon-mediated antiviral response. Evaluation of 30 cytokines/chemokines by multiplex assay showed an increased level of interferon-induced chemokine CXCL10 (IP-10) at 24 h and 3 days post-vaccination in the AS37-adjuvanted vaccine groups. Increases in activated plasmacytoid dendritic cells (pDC) and intermediate monocytes were detected 3 days post-vaccination in the AS37-adjuvanted vaccine groups. T follicular helper (Tfh) cells increased 7 days post-vaccination and were maintained at 28 days post-vaccination, particularly in the AS37-adjuvanted vaccine groups. Moreover, most of the subjects that received vaccine containing 25, 50 and 100 µg TLR7a showed an increased MenC-specific memory B cell responses versus baseline. These data show that the adsorption of TLR7a to alum promotes an immune signature consistent with TLR7 engagement, with up-regulation of interferon-inducible genes, cytokines and frequency of activated pDC, intermediate monocytes, MenC-specific memory B cells and Tfh cells. TLR7a 25-50 µg can be considered the optimal dose for AS37, particularly for the adjuvanted MenC-CRM₁₉₇ conjugate vaccine.

Identification of potential biomarkers for systemic lupus erythematosus by integrated analysis of gene expression and methylation data

INTRODUCTION

Systemic lupus erythematosus (SLE) is a heterogeneous and chronic autoimmune disease. Aberrant DNA methylation occurs during various processes of SLE development regulating the mRNA expression of interrelated genes. This study aims to screen potential DNA methylation markers for SLE.

METHODS

Gene expression and methylation datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between SLE patients and healthy controls were screened using the limma R package, and differentially methylated positions (DMPs) and regions (DMRs) were identified using dmpfinder and bumphunter (minfi). Additionally, the DNA methylation markers to distinguish SLE patients from healthy controls were explored through receiver operating characteristic (ROC) curves and logistic regression analyses. Finally, we validated the results of the bioinformatic analysis by pyrosequencing.

RESULTS

In total, 91 DEGs, 90,092 DMPs, 15 DMRs, and 13 DMR-associated genes were identified. Through the integrative analysis of DEG- and DMR-associated genes, we identified five type I interferon (IFN)-related genes as key epigenetic-driven genes in SLE. GO enrichment analysis showed that the five SLE-associated epigenetic-driven genes were mainly enriched in the type I IFN signaling pathway involved in immune response and defense response to virus. Moreover, we identified two SLE-specific DNA methylation markers, three SLE without lupus nephritis (SLE-LN^-)-specific DNA methylation markers, and two SLE with lupus nephritis (SLE-LN⁺)-specific DNA methylation markers by stepwise logistic regression.

CONCLUSIONS

Overall, our study demonstrates potential DNA methylation markers of SLE, SLE-LN^-, and SLE-LN⁺, which may help the diagnosis, boost the development of new epigenetic therapy, and contribute to individualized treatment. Key Points • This study identified five type I IFN-related genes as key epigenetic-driven genes in SLE, which support the importance of the type I IFN pathway in the pathogenesis of SLE • We identified novel DNA methylation biomarkers in SLE, SLE-LN-, and SLE-LN+ by a comprehensive analysis of bioinformatics methods and executed experimental validation, and binary logistic regression analysis showed that they have excellent potential • These results may provide new insights into the biological mechanisms of SLE, and identify reliable biomarkers for SLE, SLE-LN-, and SLE-LN+, which may contribute to diagnosis and individualized treatment.

Mouse Models of Henipavirus Infection

The Nipah and Hendra viruses, belonging to henipavirus genus, are recently emerged zoonotic pathogens that cause severe and often fatal, neurologic, and/or respiratory diseases in both humans and various animals. As mice represent a small animal model convenient to study viral infections and provide a well-developed experimental toolbox for analysis in immunovirology, we describe in this chapter a few basic methods used in biosafety 4 level (BSL4) conditions to study henipavirus infection in mice.

Type I and II interferon signaling in colorectal cancer liver metastasis

Metastatic colorectal cancer is one of the leading causes of cancer-related deaths worldwide. Traditional chemotherapy extended the lifespan of cancer patients by only a few months, but targeted therapies and immunotherapy prolonged survival and led to long-term remissions in some cases. Type I and II interferons have direct pro-apoptotic and anti-proliferative effects on cancer cells and stimulate anti-cancer immunity. As a result, interferon production by cells in the tumor microenvironment is in the spotlight of immunotherapies as it affects the responses of anti-cancer immune cells. However, promoting effects of interferons on colorectal cancer metastasis have also been reported. Here we summarize our knowledge about pro- and anti-metastatic effects of type I and II interferons in colorectal cancer liver metastasis and discuss possible therapeutic implications.

Effect of CRISPR/Cas9-mediated knockout of either IRF-3 or IRF-5 gene in Epithelioma papulosum cyprini cells on type I interferon response and NF-κB activity

Transcription factors related to the activation of type I interferons (IFNs) and nuclear factor-kappa B (NF-κB) are known to be critical in innate immune responses. Interferon regulatory factors (IRFs) are a family of transcription factors. IRF-3 is known to act as the primary regulator in type I IFN signaling in response to viral infections, and the upregulation of IRF5 by virus infection has been reported in various fish species. One of the ways to know the functional role of certain genes is the production of target gene(s) knockout cells or organisms. In the present study, we produced either IRF3 or IRF5 gene knockout Epithelioma papulosum cyprini (EPC) cells using a CRISPR/Cas9 system, and investigated the effect of IRF3 gene and IRF5 gene knockout on polyinosinic:polycytidylic acid (ploly (I:C))-mediated and viral hemorrhagic septicemia virus (VHSV) infection-mediated type I IFN response and NF-κB activation. Both IRF3 knockout and IRF5 knockout EPC cells showed severely decreased type I IFN responses measured by ISRE activity and the expression of Mx1 and ISG15 genes when stimulated with poly (I:C), while the decreased level of type I IFN responses was not high as by poly (I:C) stimulation when infected with VHSV. Different from type I IFN response, NF-κB activities in IRF3 and IRF5 knockout cells were not highly different between poly (I:C) stimulated cells and VHSV-infected cells. Further studies are needed to elucidate pathways responsible for the type I IFN responses and NF-κB activation by VHSV infection.