InVivoMAb anti-mouse IFNAR-1

The proteasome inhibitor bortezomib induces apoptosis in multiple myeloma cells and has transformed patient outcome. Using in vitro as well as in vivo immunodeficient and immunocompetent murine multiple myeloma models, we here show that bortezomib also triggers immunogenic cell death (ICD), characterized by exposure of calreticulin on dying multiple myeloma cells, phagocytosis of tumor cells by dendritic cells, and induction of multiple myeloma-specific immunity. We identify a bortezomib-triggered specific ICD gene signature associated with better outcome in two independent cohorts of patients with multiple myeloma. Importantly, bortezomib stimulates multiple myeloma cell immunogenicity via activation of the cGAS/STING pathway and production of type I IFNs, and STING agonists significantly potentiate bortezomib-induced ICD. Our study therefore delineates mechanisms whereby bortezomib exerts immunotherapeutic activity and provides the framework for clinical trials of STING agonists with bortezomib to induce potent tumor-specific immunity and improve patient outcome in multiple myeloma. SIGNIFICANCE: Our study demonstrates that cGAS/STING-dependent immunostimulatory activity mediates bortezomib anti-myeloma activity in experimental models and associates with clinical response to bortezomib in patients with multiple myeloma. These findings provide the rationale for clinical evaluation of STING agonists to further potentiate anti-multiple myeloma immune response.See related commentary by Zitvogel and Kroemer. ©2021 American Association for Cancer Research.

Immune checkpoint inhibitors (ICIs) extend survival in many patients with cancer but are ineffective in patients without pre-existing immunity1-9. Although personalized mRNA cancer vaccines sensitize tumours to ICIs by directing immune attacks against preselected antigens, personalized vaccines are limited by complex and time-intensive manufacturing processes10-14. Here we show that mRNA vaccines targeting SARS-CoV-2 also sensitize tumours to ICIs. In preclinical models, SARS-CoV-2 mRNA vaccines led to a substantial increase in type I interferon, enabling innate immune cells to prime CD8+ T cells that target tumour-associated antigens. Concomitant ICI treatment is required for maximal efficacy in immunologically cold tumours, which respond by increasing PD-L1 expression. Similar correlates of vaccination response are found in humans, including increases in type I interferon, myeloid-lymphoid activation in healthy volunteers and PD-L1 expression on tumours. Moreover, receipt of SARS-CoV-2 mRNA vaccines within 100 days of initiating ICI is associated with significantly improved median and three-year overall survival in multiple large retrospective cohorts. This benefit is similar among patients with immunologically cold tumours. Together, these results demonstrate that clinically available mRNA vaccines targeting non-tumour-related antigens are potent immune modulators capable of sensitizing tumours to ICIs.

The variety and functionality of current clinical vaccine adjuvants remain limited. Conventional aluminum-based adjuvants predominantly induce Th2-biased humoral immunity but exhibit a limited capacity to elicit Th1-mediated cellular immune responses, particularly tumor antigen-specific cytotoxic CD8+ T lymphocytes (CTLs), which are essential for effective cancer vaccine performance. Inspired by natural biomolecular condensates, we developed a versatile noncovalent protein self-assembly strategy distinct from traditional approaches requiring structural domain modifications or bifunctional crosslinkers. Our methodology employs amphiphilic molecules (sodium myristate/SMA and sodium dodecyl thiolate/SDT) as molecular bridges to mediate protein‒protein interactions through hydrophobic forces and disulfide bond formation. This process generates nanoscale protein condensate (PCD) vaccines with exceptional stability. As a novel adjuvant system, these synthetic condensates significantly enhance antigen cross-presentation by optimizing key parameters: antigen loading capacity, lymph node targeting, cytosolic delivery, and lysosomal escape. Consequently, they induce robust antigen-specific CTL responses and humoral immunity, demonstrating potent antitumor efficacy. Importantly, we found that the synthetic protein condensate (PCD) alone can act as a nanoadjuvant. By increasing mitochondrial membrane permeability, PCD induces mitochondrial DNA leakage into the cytosol, activating the cGAS‒STING pathway and promoting DC maturation. This safe and scalable platform eliminates the need for complex covalent modifications or genetic engineering, and it facilitates the design of diverse modular antigens, including neoantigens and viral antigens. Given its straightforward manufacturing process and superior immunogenicity, this synthetic PCD vaccine adjuvant has significant potential for clinical application and translation.

Beyond supporting cancer cell proliferation, tumor growth relies on the ability of cancer cells to evade immune surveillance. Identifying novel molecules that promote tumor immune escape may help develop more effective immunotherapeutic strategies. The histone acetyltransferase E1A-binding protein p300 (EP300) is a key epigenetic regulator that modulates gene transcription through chromatin remodeling and acetylation of histones and transcription factors. However, its role in regulating immune evasion remains incompletely understood. This study investigates the impact of EP300 on tumor immune escape and suggests its potential as an immunotherapeutic target.

Bacteria of the genus Shigella replicate in intestinal epithelial cells and cause shigellosis, a severe diarrheal disease that resolves spontaneously in most healthy individuals. During shigellosis, neutrophils are abundantly recruited to the gut and have long been thought to be central to Shigella control and pathogenesis. However, how shigellosis resolves remains poorly understood due to the longstanding lack of a tractable and physiological animal model. Here, using our newly developed Nlrc4-/-Casp11-/- mouse model of shigellosis, we unexpectedly find no major role for neutrophils in limiting Shigella or in disease pathogenesis. Instead, we uncover an essential role for macrophages in the host control of Shigella. Macrophages respond to Shigella via Toll-like receptors (TLRs) to produce IL-12, which then induces IFN-γ, a cytokine that is essential to control Shigella replication in intestinal epithelial cells. Collectively, our findings reshape our understanding of the innate immune response to Shigella.

The ability of bacteria and viruses to selectively replicate in tumours has led to synthetic engineering of new microbial therapies. Here we design a cooperative strategy whereby Salmonella typhimurium bacteria transcribe and deliver the Senecavirus A RNA genome inside host cells, launching a potent oncolytic viral infection. 'Encapsidated' by bacteria, the viral genome can further bypass circulating antiviral antibodies to reach the tumour and initiate replication and spread within immune mice. Finally, we engineer the virus to require a bacterially delivered protease to achieve virion maturation, demonstrating bacterial control over the virus. Together, we refer to this platform as 'CAPPSID' for Coordinated Activity of Prokaryote and Picornavirus for Safe Intracellular Delivery. This work extends bacterially delivered therapeutics to viral genomes, and shows how a consortium of microbes can achieve a cooperative aim.

Viral infections disrupt glucose metabolism; however, their impact on disease prognosis in highly pathogenic viruses remains largely unknown. There is an additional need to investigate the antiviral mechanisms of glucose-lowering therapeutics. Here, our multicenter clinical study shows that hyperglycemia and pre-existing diabetes are independent risk factors for mortality in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging and highly pathogenic bunyavirus. SFTSV infection triggers gluconeogenesis, which, in turn, inhibits AMPK activity and subsequent interferon I (IFN-I) responses, thereby facilitating viral replication. In vitro and animal studies further reveal that metformin inhibits SFTSV replication by suppressing autophagy through the AMPK-mTOR pathway, contributing to protection against lethal SFTSV infection in mice. Importantly, our large cohort study demonstrates that metformin reduces viremia and SFTSV-related mortality in patients with hyperglycemia or pre-existing diabetes, contrasting with the disadvantageous effect of insulin. These findings highlight the promising therapeutic potential of metformin in treating viral infections, particularly among individuals with hyperglycemia or diabetes.

Viral infections disrupt glucose metabolism; however, their impact on disease prognosis in highly pathogenic viruses remains largely unknown. There is an additional need to investigate the antiviral mechanisms of glucose-lowering therapeutics. Here, our multicenter clinical study shows that hyperglycemia and pre-existing diabetes are independent risk factors for mortality in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging and highly pathogenic bunyavirus. SFTSV infection triggers gluconeogenesis, which, in turn, inhibits AMPK activity and subsequent interferon I (IFN-I) responses, thereby facilitating viral replication. In vitro and animal studies further reveal that metformin inhibits SFTSV replication by suppressing autophagy through the AMPK-mTOR pathway, contributing to protection against lethal SFTSV infection in mice. Importantly, our large cohort study demonstrates that metformin reduces viremia and SFTSV-related mortality in patients with hyperglycemia or pre-existing diabetes, contrasting with the disadvantageous effect of insulin. These findings highlight the promising therapeutic potential of metformin in treating viral infections, particularly among individuals with hyperglycemia or diabetes.

Viral infections disrupt glucose metabolism; however, their impact on disease prognosis in highly pathogenic viruses remains largely unknown. There is an additional need to investigate the antiviral mechanisms of glucose-lowering therapeutics. Here, our multicenter clinical study shows that hyperglycemia and pre-existing diabetes are independent risk factors for mortality in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging and highly pathogenic bunyavirus. SFTSV infection triggers gluconeogenesis, which, in turn, inhibits AMPK activity and subsequent interferon I (IFN-I) responses, thereby facilitating viral replication. In vitro and animal studies further reveal that metformin inhibits SFTSV replication by suppressing autophagy through the AMPK-mTOR pathway, contributing to protection against lethal SFTSV infection in mice. Importantly, our large cohort study demonstrates that metformin reduces viremia and SFTSV-related mortality in patients with hyperglycemia or pre-existing diabetes, contrasting with the disadvantageous effect of insulin. These findings highlight the promising therapeutic potential of metformin in treating viral infections, particularly among individuals with hyperglycemia or diabetes.

Viral infections disrupt glucose metabolism; however, their impact on disease prognosis in highly pathogenic viruses remains largely unknown. There is an additional need to investigate the antiviral mechanisms of glucose-lowering therapeutics. Here, our multicenter clinical study shows that hyperglycemia and pre-existing diabetes are independent risk factors for mortality in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging and highly pathogenic bunyavirus. SFTSV infection triggers gluconeogenesis, which, in turn, inhibits AMPK activity and subsequent interferon I (IFN-I) responses, thereby facilitating viral replication. In vitro and animal studies further reveal that metformin inhibits SFTSV replication by suppressing autophagy through the AMPK-mTOR pathway, contributing to protection against lethal SFTSV infection in mice. Importantly, our large cohort study demonstrates that metformin reduces viremia and SFTSV-related mortality in patients with hyperglycemia or pre-existing diabetes, contrasting with the disadvantageous effect of insulin. These findings highlight the promising therapeutic potential of metformin in treating viral infections, particularly among individuals with hyperglycemia or diabetes.

Crimean-Congo haemorrhagic fever virus (CCHFV) is the most prevalent tick-borne zoonotic bunyavirus, causing severe hemorrhagic fever and fatality in humans. Currently, the absence of approved vaccines or therapeutics for CCHFV infection necessitates the development of innovative therapeutic strategies. Here, we identify a guanine (G)-rich sequence located within the mRNA of the glycoprotein precursor in the medium (M) segment of the CCHFV genome, designated as M-PQS-1664(+). M-PQS-1664(+) can form stable G-quadruplex (G4) structure and functions as a negative regulatory element for viral replication. Host DDX60 is up-regulated in response to CCHFV infection, thereby it is hijacked to unwind M-PQS-1664(+) G4 for facilitating viral replication. The FDA-approved drug Cepharanthine (CEP), which competes with DDX60 to specifically stabilize M-PQS-1664(+) G4 without a global induction of host cellular G4s formation, exhibits remarkable antiviral activity in vitro and in vivo. More importantly, CEP possesses antiviral activity (50% inhibitory concentration ~ 0.2 μM) that having ~ 88 × the potency of ribavirin. Our findings underscore the CCHFV G4s as a promising target for drug development and highlight the significant potential of CEP in combating CCHFV.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced impaired antiviral immunity and excessive inflammatory responses cause lethal pneumonia. However, the in vivo roles of key pattern recognition receptors that elicit protective antiviral and fatal inflammatory responses, specifically in the lungs, are not well described. Coronaviruses possess single-stranded RNA genome that activates TLR7/8 to induce an antiviral interferon (IFN) and robust inflammatory cytokine response. Here, using wild-type and TLR7-deficient (TLR7-/-) mice infected with mouse-adapted SARS-CoV-2 (MA-CoV-2), we examined the role of TLR7 in the lung antiviral and inflammatory response and severe pneumonia. We showed that TLR7 deficiency significantly increased lung virus loads and morbidity/mortality, which correlated with reduced levels of type I IFNs (Ifna/b), type III IFNs (Ifnl), and IFN-stimulated genes (ISGs) in the lungs. A detailed evaluation of MA-CoV-2-infected lungs revealed increased neutrophil accumulation and lung pathology in TLR7-/- mice. We further showed that blocking type I IFN receptor (IFNAR) signaling enhanced SARS-CoV-2 replication in the lungs and caused severe lung pathology, leading to 100% mortality compared to infected control mice. Moreover, immunohistochemical assessment of the lungs revealed increased numbers of SARS-CoV-2 antigen-positive macrophages, pneumocytes, and bronchial epithelial cells in TLR7-/- and IFNAR-deficient mice compared to control mice. In summary, we conclusively demonstrated that despite TLR7-induced robust lung inflammation, TLR7-induced IFN/ISG responses suppress lung virus replication and pathology and provide protection against SARS-CoV-2-induced fatal pneumonia. Additionally, given the similar disease outcomes in control, TLR7-/-, and IFNAR-deficient MA-CoV-2-infected mice and coronavirus disease 2019 (COVID-19) patients, we propose that MA-CoV-2-infected mice constitute an excellent model for studying COVID-19.IMPORTANCESevere coronavirus disease 2019 (COVID-19) is caused by a delicate balance between a strong antiviral and an exuberant inflammatory response. A robust antiviral immunity and regulated inflammation are protective, while a weak antiviral response and excessive inflammation are detrimental. However, the key host immune sensors that elicit protective antiviral and inflammatory responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenge are poorly defined. Here, we examined the role of viral RNA-mediated TLR7 activation in the lung antiviral and inflammatory responses in SARS-CoV-2-infected mice. We demonstrate that TLR7 deficiency led to a high rate of morbidity and mortality, which correlated with an impaired antiviral interferon (IFN)-I/III response, enhanced lung virus replication, and severe lung pathology. Furthermore, we show that blocking IFN-I signaling using anti-IFN receptor antibody promoted SARS-CoV-2 replication in the lungs and caused severe disease. These results provide conclusive evidence that TLR7 and IFN-I receptor deficiencies lead to severe disease in mice, replicating clinical features observed in COVID-19 patients.

In anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) and systemic lupus erythematosus (SLE), glomerulonephritis is a severe kidney complication driven by immune cells, including T cells. However, the mechanisms underlying T cell activation in these contexts remain elusive. Here we report that in patients with AAV and SLE, type I interferon (IFN-I) induces T cell differentiation into interferon-stimulated genes-expressing T (ISG-T) cells, which are characterized by an elevated IFN-I signature, an immature phenotype, and cytotoxicity in inflamed tissue. Mechanistically, IFN-I stimulates the expression of interferon regulatory factor 7 (IRF7) in T cells, which in turn induces granzyme B production. In mice, blocking IFN-I signaling reduces IRF7 and granzyme B expression in T cells, thus ameliorating glomerulonephritis. In parallel, spatial transcriptomic analyses of kidney biopsies from patients with AAV or SLE reveal an elevated ISG signature and the presence of ISG-T cells in close proximity to plasmacytoid dendritic cells, the primary producers of IFN-I. Our results from both patients and animal models thus suggest that IFN-I production in inflamed tissue may drive ISG-T cell differentiation to expand the pool of cytotoxic T cells in autoimmune diseases.

Mitochondrial diseases (MtD) represent a significant public health challenge due to their heterogenous clinical presentation, often severe and progressive symptoms, and lack of effective therapies. Environmental exposures, such bacterial and viral infection, can further compromise mitochondrial function and exacerbate the progression of MtD. However, the underlying immune alterations that enhance immunopathology in MtD remain unclear. Here we employ in vitro and in vivo approaches to clarify the molecular and cellular basis for innate immune hyperactivity in models of polymerase gamma (Polg)-related MtD. We reveal that type I interferon (IFN-I)-mediated upregulation of caspase-11 and guanylate-binding proteins (GBP) increase macrophage sensing of the opportunistic microbe Pseudomonas aeruginosa (PA) in Polg mutant mice. Furthermore, we show that excessive cytokine secretion and activation of pyroptotic cell death pathways contribute to lung inflammation and morbidity after infection with PA. Our work provides a mechanistic framework for understanding innate immune dysregulation in MtD and reveals potential targets for limiting infection- and inflammation-related complications in Polg-related MtD.

Yellow fever (YFV) and Zika (ZIKV) viruses cause significant morbidity and mortality, despite the existence of an approved YFV vaccine and the development of multiple ZIKV vaccine candidates to date. New technologies may improve access to vaccines against these pathogens. We previously described a nanostructured lipid carrier (NLC)-delivered self-amplifying RNA (saRNA) vaccine platform with excellent thermostability and immunogenicity, appropriate for prevention of tropical infectious diseases.

Tumor cells often employ many ways to restrain type I IFN signaling to evade immune surveillance. However, whether cellular amino acid metabolism regulates this process remains unclear, and its effects on antitumor immunity are relatively unexplored. Here, we found that asparagine inhibited IFN-I signaling and promoted immune escape in bladder cancer. Depletion of asparagine synthetase (ASNS) strongly limited in vivo tumor growth in a CD8+ T cell-dependent manner and boosted immunotherapy efficacy. Moreover, clinically approved L-asparaginase (ASNase),synergized with anti-PD-1 therapy in suppressing tumor growth. Mechanistically, asparagine can directly bind to RIG-I and facilitate CBL-mediated RIG-I degradation, thereby suppressing IFN signaling and antitumor immune responses. Clinically, tumors with higher ASNS expression show decreased responsiveness to immune checkpoint inhibitor therapy. Together, our findings uncover asparagine as a natural metabolite to modulate RIG-I-mediated IFN-I signaling, providing the basis for developing the combinatorial use of ASNase and anti-PD-1 for bladder cancer.

Type I Interferons (IFN-I) are central to host protection against viral infections, with plasmacytoid dendritic cells (pDC) being the most significant source, yet pDCs lose their IFN-I production capacity following an initial burst of IFN-I, resulting in susceptibility to secondary infections. The underlying mechanisms of these dynamics are not well understood. Here we find that viral infection reduces the capacity of pDCs to engage both oxidative and glycolytic metabolism. Mechanistically, we identify lactate dehydrogenase B (LDHB) as a positive regulator of pDC IFN-I production in mice and humans; meanwhile, LDHB deficiency is associated with suppressed IFN-I production, pDC metabolic capacity, and viral control following infection. In addition, preservation of LDHB expression is sufficient to partially retain the function of otherwise exhausted pDCs, both in vitro and in vivo. Furthermore, restoring LDHB in vivo in pDCs from infected mice increases IFNAR-dependent, infection-associated pathology. Our work thus identifies a mechanism for balancing immunity and pathology during viral infections, while also providing insight into the highly preserved infection-driven pDC inhibition.