Fracture healing is an evolutionarily conserved process that depends on the complex interplay of osteogenic, angiogenic, and inflammatory responses. Impaired bone healing is observed in up to 10 to 15% of patients with fractures and can lead to nonunion, which is the absence of bone healing. Here, we explore a role of neutrophil extracellular traps (NETs) in fracture healing and their association with nonunion. In both mice and humans, skeletal injury triggers rapid but transient NET formation at the fracture site. The combined genetic deletion of enzymes essential for NET clearance, DNase1 and DNase1-like-3 , initially favors callus mineralization in the early healing phase. However, sustained NET elevation subsequently leads to impaired bone regeneration and fracture nonunion over the course of healing. Conversely, additional deletion of the NET-generating enzyme Pad4 improves bone regeneration and lowers nonunion rates. Mechanistically, NETs up-regulate cGas-Sting signaling, thereby collapsing the formation of type-H vessels, which couple osteogenesis to angiogenesis in the fracture callus. Pharmacological inhibition of cGas-Sting restored type-H vessels, enhanced bone healing, and prevented nonunion in DNase -deficient but not Pad4 -deficient mice. In patients, serum NET markers declined during normal healing but were elevated in nonunion, correlating with excessive NET and STING accumulation in the callus. Therapeutically, the inhibition of NET formation with the Pad4 inhibitor GSK484 or the promotion of NET clearance with dornase alfa (recombinant DNase1) accelerated bone repair and prevented nonunion in preclinical models. These findings identify sustained NETs as a disruptor of fracture healing and a potential target for enhancing bone regeneration.
There is currently no approved vaccine for Shigella spp., a leading cause of diarrhea with increasing rates of antimicrobial resistance. Shigella vaccine development is complicated in part by an incomplete understanding of the structural and molecular determinants of immunity. To address this, we isolated monoclonal antibodies against candidate Shigella vaccine antigens using samples from a Shigella flexneri outbreak in a nonhuman primate (NHP) research facility. We found that antibodies targeting the Shigella O-antigen can undergo substantial affinity maturation (>10%) to acquire broad cross-reactivity across S. flexneri serotypes. We also found that the virulence-associated type III secretion system (T3SS) proteins IpaD and IpaB elicit moderate T cell and robust antibody responses. T3SS antibodies could either inhibit or enhance bacterial virulence in vitro and differed in vivo depending on their epitope specificity. Collectively, these findings provide insights into protective and deleterious immune responses against Shigella that directly inform vaccine immunogen design.
Most persons living with HIV-1 who discontinue antiretroviral therapy (ART) demonstrate viral rebound, but the tissue-level events that lead to rebound viremia remain poorly understood. Here, we report the origin, dynamics, and correlates of viral rebound in 16 rhesus macaques (RMs) infected with molecularly barcoded SIVmac239M, treated with ART for 70 weeks, and necropsied on day 12 after ART discontinuation. Barcode analysis of plasma during daily post-ART sampling identified 1 to 38 rebounding viral lineages per animal, with a mean of 2.4 lineages contributing to initial rebound viremia. Analysis of barcode viral RNA expression in tissues revealed presumptive anatomic origin sites for 56 of 175 rebounding viral lineages, with enrichment in the gastrointestinal (GI) tract and GI-associated lymph nodes by mixed-effects logistic regression. Daily transcriptomic and proteomic profiling in peripheral blood after ART discontinuation showed up-regulation of pathways related to T cell signaling, cytokine responses, and cellular metabolism before detectable rebound viremia. These data show that viral rebound is initiated by oligofocal tissue expansion of a limited number of clonal lineages, followed by systemic dissemination and serial emergence of additional lineages from multiple tissues. Longer time to viral rebound was associated with metabolic, epigenetic, and immunologic signatures that suppress proviral reactivation. These findings advance our understanding of the tissue origins and host correlates of viral rebound and provide a framework for future studies examining GI-associated reservoir compartments, peripheral blood biomarker development, and host-directed strategies to prolong ART-free viral remission.
The skull bone marrow (SBM) is emerging as a critical hub for neuroimmune signaling, yet its role in chronic pain is unknown. Using integrated positron emission tomography/magnetic resonance imaging, here, we show that the levels of 18-kilodalton translocator protein (TSPO), a putative marker of immune cell density, are elevated in the SBM of individuals with chronic pain [n = 125; chronic low back pain (cLBP), n = 88; knee osteoarthritis (KOA), n = 37] compared with healthy controls (n = 22). These elevations were widespread, generally more pronounced for KOA than cLBP, associated with pain and pain-comorbid symptoms in partially segregated spatial patterns, and supported by preliminary immunohistochemical evidence in human SBM samples from a donor with a history of chronic pain (compared with a healthy donor). Because TSPO is highly expressed in myeloid cells, these results link SBM immune dysregulation with chronic pain and its associated psychological and functional impairments. These findings provide a strong rationale for investigating this previously overlooked structure, which remains largely underexplored in the context of pain.
Recent evidence implicates a metabolic switch in afferent spinal circuits as a key driver of the transition from acute pain- to chronic pain-related behaviors in mice after tissue injury, yet the cellular substrates and functional consequences remain incompletely defined. Using a combination of pharmacological and genetic approaches, we investigated whether metabolic reprogramming in spinal cord cell populations constitutes a causal mechanism linking peripheral injury to the progression to pain chronicity. After peripheral injury induced by a hindpaw formalin injection in mice, single-nucleus RNA sequencing (snRNA-seq) revealed that spinal oligodendrocytes down-regulated transcripts for myelin protein synthesis and up-regulated transcripts important for lipid biosynthesis. Comparative lipidomics showed that this resource reallocation after peripheral injury was associated with disrupted spinal myelin composition. Moreover, axonal integrity was compromised, causing neuronal accumulation of amyloid precursor protein, enhanced β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) expression, and increased insoluble amyloid-β42 (Aβ42) during a critical temporal window for the transition to pain chronicity. Blocking Aβ42 production by BACE1 inhibition or clearing Aβ42 by intrathecal 4G8 monoclonal antibody injection prevented the emergence of persistent pain after hindpaw formalin injection. Oligodendrocyte-specific deletion of N-acylethanolamine acid amidase, a key regulator of cell metabolism and pain, prevented Aβ42 release and chronic pain development induced by formalin injection or sciatic nerve ligation. These findings uncover an unexpected mechanistic link between chronic pain and amyloid pathology and identify the NAAA→Aβ42 pathway as a target for disease-modifying intervention.
Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that leads to right heart failure and ultimately death. Therapeutic options targeting the underlying mechanisms of the disease are urgently needed. MicroRNAs (miRs) have emerged as critical regulators of cardiovascular homeostasis and disease. Here, we identified microRNA-224-5p (miR-224) as a regulator of pulmonary vascular remodeling and delineate its mechanism of action in PAH. miR-224 expression was increased in the lungs of patients with PAH and across multiple experimental models of pulmonary hypertension, including mouse, rat, and pig models, as well as in pulmonary arterial smooth muscle cells (PASMCs) isolated from patients with PAH. In vitro, miR-224 overexpression was sufficient to induce PASMC proliferation. In vivo, adeno-associated virus 1 (AAV1)-mediated overexpression of miR-224 exacerbated PAH in mice, whereas intratracheal delivery of aerosolized AAV1-ToughDecoy-miR-224 or a chemically modified antisense oligonucleotide targeting miR-224 (LNA-224) attenuated disease severity in Sugen/Hypoxia (Su/Hx) and monocrotaline models in both mice and rats. Moreover, SMC-specific inhibition of miR-224 via an AAV1 vector expressing ToughDecoy-miR-224 reversed pulmonary vascular remodeling and improved right ventricular function in the Su/Hx mouse model. Mechanistically, miR-224 targeted multiple components of the bone morphogenetic protein (BMP)/transforming growth factor-β (TGFβ) signaling pathway, leading to suppressed BMP/SMAD signaling and enhanced TGFβ-associated responses. Inhibition of miR-224 restored the balance between growth-inhibitory BMP signaling and growth-promoting TGFβ signaling in PASMCs. Collectively, these findings identify miR-224 as a regulator of pulmonary vascular remodeling and highlight miR-224 inhibition as a promising therapeutic strategy for PAH.
Two live-attenuated vaccines, LMA and LMP, were evaluated alone or in combination with a trivalent adenoviral vector-based vaccine (Ad5-YFV) for their protective efficacy against pneumonic plague in wild-type (WT) and interferon-γ (IFN-γ) knockout (KO) mice. LMA and LMP comprise triple deletion mutants of Yersinia pestis CO92, which causes pneumonic plague, and Ad5-YFV incorporates three protective plague immunogens. Protection of 80 to 100% was observed in vaccinated mice when challenged with highly lethal intranasal doses of parental Y. pestis CO92. All vaccinated mice generated robust humoral and cellular immune responses. Immunized WT mice generated overall greater antibody responses in both serum and bronchoalveolar lavage fluid with higher percentages of polyfunctional T cell populations. Vaccinated IFN-γ KO mice displayed better B cell activity in germinal centers with higher percentages of activated antigen-specific and memory T cells. Superior lung immunity and recall immune responses were observed in both WT and IFN-γ KO mice immunized using a prime-pull vaccine strategy, which also provided full protection against pneumonic plague to mice lacking IFN-α, IFN-β, and IFN-γ receptors. Depletion of IFN-γ or tumor necrosis factor-α from immunized WT mice before and during infection did not reduce protection against pulmonary Y. pestis CO92 challenge. These data suggest that IFN-γ may not be required for protection against pneumonic plague by these vaccines. Combining live-attenuated and adenovirus-based vaccines resulted in augmentation of systemic and local immune responses, which could be beneficial in providing long-lasting immunity against pneumonic plague.
Chimeric antigen receptor (CAR) T cell therapy for acute myeloid leukemia (AML) is constrained by antigen heterogeneity and shared expression with healthy compartments, and there are often challenges in obtaining autologous T cells from heavily pretreated patients. To address these challenges, we developed universal donor-derived, base-edited, anti-CD33 CAR T cells (BE-CAR33) that used precise multiplexed cytidine deamination to simultaneously disrupt the TRAC, CD52, and CD7 loci to prevent graft-versus-host disease and evade immunotherapy effects. An open-label, nonrandomized, single-center phase 1 study (ISRCTN14430213) evaluated the safety, feasibility, and activity of BE-CAR33 cell therapy ahead of allogeneic stem cell transplantation (allo-SCT) for patients with AML. Eligible participants were aged less than 16 years with relapsed/refractory AML. Five patients were screened, and three were enrolled; one additional adult received BE-CAR33 through compassionate access. Participants received fludarabine, cyclophosphamide, and alemtuzumab followed by 1.2 to 1.8 × 106 BE-CAR33 cells per kilogram. Treatment-emergent adverse events included cytokine release syndrome (grade ≤2), neurotoxicity (grade 3), cytopenias (grade 4), and transient rashes. Two patients demonstrated reduced minimal residual disease and proceeded to allo-SCT. Serial flow cytometry, chimerism quantification, and vector copy number analyses tracked BE-CAR33 T cells until elimination during transplant. Differentially expressed genes included editing signatures and switched from manufacturing-related toward postexpansion effector and exhaustion profiles. Although primary end points were not met, this first-in-human study demonstrated the feasibility of an "off-the-shelf" base-edited CAR T cell approach and informs future multiantigen strategies against AML.
For metastatic colonization to occur, disseminated tumor cells must survive, adapt to, and remodel distant microenvironments in an organ-specific manner. We established a human multitissue model of cancer spread, with engineered bone and lung linked by vascular flow containing circulating cancer cells. Parental MDA-MB-231 cells extravasated toward both tissues, remodeled their niches, and acquired transcriptional programs reflecting adaptation to the local microenvironment, particularly upon homing to bone. Tissue-specific colonization by the bone- and lung-tropic MDA-MB-231 derivatives was quantified in independently perfused bone or lung platforms. Consistent with in vivo behavior, bone-tropic cells showed stronger bone colonization than lung-tropic cells and induced more pronounced osteolysis. In contrast, lung-tropic cells caused greater epithelial disruption in lung tissue and only modest colonization of bone. Distinct patterns of tissue colonization and secreted factors demonstrate that this device recapitulates key features of organ-specific metastasis observed in vivo for this family of cell lines.
Frontotemporal dementia is commonly caused by loss-of-function mutations in the progranulin gene. Potential therapies for this disorder have entered clinical trials, including progranulin gene therapy and drugs that reduce progranulin interactions with sortilin. Both approaches ameliorate functional and pathological abnormalities in mouse models of progranulin insufficiency. Here, we investigated whether modifying the progranulin carboxyl terminus to block sortilin interactions would improve the efficacy of progranulin gene therapy. We compared the effects of treating progranulin-deficient mice with gene therapy vectors expressing progranulin with intact sortilin interactions, progranulin with the carboxyl terminus blocked to reduce sortilin interactions, or GFP control. We found that expressing carboxyl-terminally blocked progranulin generated higher levels of progranulin both at the injection site and in more distant regions. Carboxyl-terminally blocked progranulin was also more effective at ameliorating microgliosis, microglial lipofuscinosis, microglial morphology changes, and lipid abnormalities including ganglioside accumulation and loss of bis(monoacylglycero)phosphate lipids. Behavioral abnormalities detected in progranulin-deficient mice using an unbiased machine learning analysis were absent after treatment with carboxyl-terminally blocked progranulin but not corrected by unblocked progranulin. Last, only carboxyl-terminally blocked progranulin reduced plasma neurofilament light chain, a biomarker of axonal damage, in progranulin-deficient mice. These results demonstrate that modifying the progranulin cargo to block sortilin interactions may be important for increasing the effectiveness of progranulin gene therapy.
Platelet dysfunction drives bleeding complications in patients with advanced chronic kidney disease (CKD), worsening clinical outcomes. However, the underlying mechanisms remain unclear, limiting treatment options. In this study, we identified the expression of urea transporter B (SLC14A1/UT-B) in human and mouse platelets. By analyzing a clinical cohort of patients with CKD, we demonstrated that single-nucleotide polymorphisms in SLC14A1 were associated with bleeding events in CKD. Using a 5/6 nephrectomy (5/6 Nx) mouse model and blood samples from patients with advanced CKD, we found that SLC14A1/UT-B-mediated urea influx underlies platelet dysfunction in advanced CKD given that both genetic knockout of Slc14a1 or pharmacological inhibition of UT-B reversed mouse and human platelet dysfunction induced by urea or advanced CKD plasma. SLC14A1/UT-B-mediated urea influx induced protein carbamylation, which drove platelet dysfunction. By characterizing the carbamylation profiles of proteins in human and mouse platelets, we demonstrated that carbamylation disrupted cytoskeletal rearrangement, degranulation, and inside-out integrin αIIbβ3 signaling transduction during platelet activation, leading to impaired platelet aggregation, secretion, and spreading in advanced CKD. Furthermore, treatment of 5/6 Nx mice with the UT-B inhibitor PU-48 effectively preserved platelet function and improved hemostatic ability. These findings suggest that SLC14A1/UT-B promoted urea uptake in platelets and mediated bleeding in advanced CKD, highlighting its potential as a therapeutic target for managing bleeding complications in patients with advanced CKD.
cfDNA fragmentomics of routine prenatal screening data identifies adverse pregnancy outcomes in immune-mediated disease (Stanley et al. , this issue).
Vaccination with real-world complex antigens often elicits a hierarchical immune response to different epitopes. This immunodominance is a major obstacle in vaccine design because nonprotective epitopes often divert the immune response away from protective epitopes. We posited that B cell epitope avidity (i.e., total multivalent binding strength) is a key regulator of immunodominance hierarchy by modulating both germinal center (GC) seeding and B cell competitive fitness in GCs. To test these hypotheses, we used two sets of mosaic nanoparticle immunogens to precisely modulate epitope avidity by varying the valency and affinity components independently while keeping nanoparticle size and helper T cell epitopes constant. We evaluated these immunogens in three HIV vaccine models that use humanized mice to recapitulate physiological precursor frequencies and affinities. Increased epitope avidity drove seeding of GCs, as well as B cell competitive fitness and immunodominance hierarchies in GCs. B cell receptor sequencing revealed that epitope valency had negligible impact on total somatic hypermutations but collectively promoted clonal diversity and affinity maturation in GCs. Restricting interclonal competition rescued early GC B cell responses to low-valency immunogens. Epitope valency and affinity worked in combination to promote GC B cell competitive fitness, although valency had prominent influences. Furthermore, both valency and affinity regulated the early extrafollicular (EF) plasma cell response in a manner dependent on interclonal competition. The data highlight the critical importance of relative epitope avidity in shaping the competitive immunodominance landscape in GC and EF responses. This should be considered when designing next-generation nanoparticle vaccines.
Huntington's disease (HD) is a progressive neurodegenerative disorder with no approved therapies. Despite multiple clinical trials, huntingtin (HTT)-lowering strategies have yet to show meaningful clinical benefit. Both somatic expansion and toxic HTT species are key molecular drivers of HD, yet therapeutic strategies targeting these pathways have never been directly compared or evaluated in combination. Using therapeutic divalent siRNAs, we assessed the long-term impact of silencing MutS homolog 3 (MSH3), a critical regulator of somatic expansion, HTT, or both in Q111 HD mice (>110 CAGs), which develop robust expansion, mutant HTT inclusions, and transcriptional dysregulation by 12 months. Long-term MSH3 silencing blocked somatic expansion, reduced inclusions, and normalized gene expression. HTT silencing alone had a limited effect, whereas combined MSH3/HTT targeting synergistically eliminated inclusions and restored transcriptomic profiles. Parallel treatment in wild-type mice showed no toxicity, supporting the safety of long-term intervention. These findings position somatic expansion as a promising therapeutic target and demonstrate the potential of RNAi-based cosilencing of MSH3 and HTT as a disease-modifying strategy for HD.
Mutations in the transcription factor gene Wilms Tumor 1 (WT1) are one of the leading causes of congenital glomerular disease, characterized by severe urinary protein loss and glomerular scarring. No disease-modifying therapies exist for WT1 glomerulopathies, and affected children rely on dialysis or kidney transplantation. We evaluated a previously uncharacterized treatment in a mouse model with an orthologous human mutation in Wt1 (Wt1+/R394W) that replicates the pathology of WT1 glomerulopathy. Lipid nanocomplexes were engineered to target integrin αvβ3 for efficient delivery of mRNA to primary podocytes and glomerular endothelial cells in vitro. A minimally invasive ultrasound-guided renal artery injection enabled precise and specific kidney localization in vivo, a finding not replicated by systemic administration. Nanocomplex-derived protein localized in glomeruli for up to 7 days in healthy and diseased mice. This platform was then used to perform an interventional preclinical trial in Wt1+/R394W mice, delivering angiopoietin-1 (Angpt1) mRNA, a vascular growth factor critical for glomerular health that is reduced in Wt1+/R394W podocytes. Angpt1 nanocomplex therapy reduced albuminuria, preserved glomerular endothelial integrity, prevented podocyte loss, and alleviated glomerulosclerosis in Wt1+/R394W mice. These findings demonstrate the therapeutic potential of this targeted approach for WT1 glomerulopathy and provide a foundation for clinical translation to improve outcomes in children with glomerular disease.
The protective benefits of vaccination can critically depend on the durability of the corresponding immune response. However, the factors influencing vaccine durability are poorly understood. Here, we tested whether antigen avidity (i.e., cumulative multivalent binding strength) affected the durability, magnitude, and diversity of the humoral immune response in preclinical HIV vaccine models. We developed neoteric mosaic nanoparticle platforms to vary antigen avidity through precise modulation of its key constituents, epitope affinity and valency, while keeping other variables constant. High-valency immunogens elicited durable and clonally diverse memory B cell (MBC) responses that were detectable for more than 1 year postprime. Increased antigen valency also drove the formation and persistence of long-lived plasma cells (LLPCs) as well as epitope-specific serum antibody responses. This appeared to be due, in part, to more robust and durable germinal center (GC) reactions that were elicited by high-valency immunogens and were detectable for upward of 6 months postprime. High-valency antigens also promoted B cell responses in a clinically relevant homologous prime-boost regimen. The positive effects of antigen avidity in driving productive B cell responses were independent of antigen dose and adjuvant. However, when interclonal competition was suppressed, MBC, LLPC, and late GC responses to low-avidity immunogens were rescued. Affinity worked in concert with valency to drive the formation of MBC responses, with valency having strong influences. Collectively, the results underscore the importance of antigen avidity in eliciting durable and diverse vaccine responses.
Adults who survive intensive care unit (ICU) admission with sepsis (sepsis survivors) have immune impairments involving concurrent inflammation and immunosuppression that increase their long-term risk of reinfections and mortality. Vaccine immunogenicity could therefore be abnormal in sepsis survivors but has never been examined. Here, in a 1:1 randomized, placebo-controlled trial, we tested the efficacy and immunogenicity of a single intramuscular dose of 13-valent pneumococcal conjugate vaccine (PCV13) in 214 sepsis survivors at ICU discharge. The PCV13 group (n = 104) experienced 43 primary outcome events (time to first infection-related rehospitalization or death during 365 days of follow-up) among 72.5 person-years of follow-up compared with 38 events among 76.5 person-years of follow-up in the placebo group (n = 110) [hazard ratio, 1.23 (95% CI, 0.80 to 1.91)]. The PCV13 group experienced higher rates of reinfections and received earlier antibiotic prescriptions in primary care. There were no vaccine-related serious adverse events. PCV13 immunogenicity assessments included serotype-specific immunoglobulin G (IgG), immunophenotyping, and pan-leukocyte RNA sequencing measured at baseline and 10 and 30 days postrandomization. PCV13-induced serotype-specific IgG responses varied across serotypes and participants, without excessive cytokine responses. PCV-induced blood transcriptional module responses in antigen-presenting cells and helper T cells were also variable. Variations in PCV13 immunogenicity were associated with age in men, body mass index in women, and cytotoxicity-associated gene modules regardless of sex. This trial showed that PCV13 administered at ICU discharge did not benefit this sepsis survivor population and underscores the need for further research to delineate treatable molecular mechanisms of postsepsis immune dysfunction (ClinicalTrials.gov identifier NCT03565159).
Acute myeloid leukemia/myelodysplastic syndromes (AML/MDSs) carrying p53 mutations are refractory to various standard therapies. Arsenic trioxide (ATO) may be effective in restoring function to p53 structural mutants. Here, we report that mutant p53 rescued by ATO treatment strengthened interferon responses triggered by the DNA hypomethylating agent decitabine by transactivating interferon regulatory factor 7 (IRF7) directly. Decitabine also increased the transactivation activity of ATO-rescued mutant p53 by inducing p53-serine-20 phosphorylation and blocking p53-inhibitory mouse double minute 2 homolog (MDM2). ATO and decitabine together killed p53-mutant AML cells and suppressed tumor growth in cell line-derived xenografts. In a first-in-human pilot clinical trial for testing the combination of ATO and decitabine (PANDA-T0 trial, NCT03855371), which enrolled five patients with AML/MDS harboring p53 structural mutations, the ATO and decitabine regimen produced manageable adverse events, and four of the five treated patients achieved complete remission at the level of the bone marrow, associated with p53 activation and interferon response. In 103 p53-mutant patients whose samples were deposited in Ruijin AML/MDS sample repository, 48 distinct p53 missense mutants were identified, 21 of which were classified as ATO and decitabine regimen applicable because of their competencies in activating p53 and interferon responses upon cotreatment. This study establishes an alternative treatment regimen for patients with p53-mutant AML/MDS and provides a proof-of-concept framework for p53-targeted therapy that differentiates between p53 mutations.
High succinate concentrations are implicated in rheumatoid arthritis (RA) and other inflammatory diseases through G protein-coupled receptor 91 (GPR91)-mediated signaling. Despite the therapeutic potential of targeting GPR91, conflicting reports on the receptor's inflammatory roles have hindered treatment development. Here, we report that the effects of succinate on GPR91 signaling are biphasic and concentration dependent. At physiological succinate concentration, membrane-localized GPR91 promotes M2 polarization through Gq-mediated activation of phospholipase C and intracellular calcium mobilization. In RA, elevated succinate induces GPR91 internalization and mitochondrial translocation, thereby disrupting Gq signaling. Mechanistically, mitochondrial GPR91 recruits Gs proteins and, together with intracellular succinate, activates the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway. PKA then phosphorylates cytidine/uridine monophosphate kinase 2 at serine-404, stabilizing it to enhance mitochondrial DNA (mtDNA) synthesis. Newly synthesized mtDNA is oxidized (forming ox-mtDNA) and released into the cytosol, activating the cyclic GMP-AMP synthase-stimulator of interferon genes pathway to drive macrophage inflammation. Myeloid-specific GPR91 deletion or inhibition of intracellular succinate accumulation alleviates arthritis in mice. This study reveals that GPR91 reprograms signaling by subcellular relocation, providing a promising therapeutic strategy for autoimmune diseases.
Assembly of flaviviruses such as Zika virus (ZIKV), dengue virus, and West Nile virus in the host cell endoplasmic reticulum is driven by the structural envelope (E) and premembrane (prM) proteins. The formation of an infectious virion requires cleavage of prM by the host furin protease during a maturation step that is dependent on a conformational change in virion structure. Here, we demonstrate that the biogenesis of flavivirus particles does not require an intact prM protein or proteolytic activation. The expression of E protein preceded by a truncated version of prM (M-E) was sufficient for the formation of noninfectious ZIKV subviral particles and pseudo-infectious reporter virions. Subviral particles encoded by a ZIKV M-E DNA vaccine elicited a neutralizing antibody response in macaques that was insensitive to the virion maturation state, a feature of flavivirus humoral immunity shown to correlate with protection. M-E vaccines that uniformly present structural features shared with mature virions offer a higher-quality and more broadly applicable approach for vaccination against flaviviruses.
