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SUMMARY Tumor-associated macrophages (TAMs) shape tumor immunity and therapeutic efficacy. However,it is poorly understood whether and how post-translational modifications (PTMs) intrinsically affect the phenotype and function of TAMs. Here,we reveal that peptidylarginine deiminase 4 (PAD4) exhibits the highest expression among common PTM enzymes in TAMs and negatively correlates with the clinical response to immune checkpoint blockade. Genetic and pharmacological inhibition of PAD4 in macrophages prevents tumor progression in tumor-bearing mouse models,accompanied by an increase in macrophage major histocompatibility complex (MHC) class II expression and T cell effector function. Mechanistically,PAD4 citrullinates STAT1 at arginine 121,thereby promoting the interaction between STAT1 and protein inhibitor of activated STAT1 (PIAS1),and the loss of PAD4 abolishes this interaction,ablating the inhibitory role of PIAS1 in the expression of MHC class II machinery in macrophages and enhancing T cell activation. Thus,the PAD4-STAT1-PIAS1 axis is an immune restriction mechanism in macrophages and may serve as a cancer immunotherapy target. Graphical Abstract In brief Pitter et al. demonstrate that the PAD4-mediated citrullination of STAT1 in macrophages enforces the STAT1-PIAS1 interaction restraining STAT1 transcriptional activity and MHC class II machinery expression and,consequently,limits T cell-mediated anti-tumor immunity. View Publication

Gene silencing without gene editing holds great potential for the development of safe therapeutic applications. Here,we describe a novel strategy to concomitantly repress multiple genes using zinc finger proteins fused to Krüppel-Associated Box repression domains (ZF-Rs). This was achieved via the optimization of a lentiviral system tailored for the delivery of ZF-Rs in hematopoietic cells. We showed that an optimal design of the lentiviral backbone is crucial to multiplex up to three ZF-Rs or two ZF-Rs and a chimeric antigen receptor. ZF-R expression had no impact on the integrity and functionality of transduced cells. Furthermore,gene repression in ZF-R-expressing T cells was highly efficient in vitro and in vivo during the entire monitoring period (up to 10 weeks),and it was accompanied by epigenetic remodeling events. Finally,we described an approach to improve ZF-R specificity to illustrate the path toward the generation of ZF-Rs with a safe clinical profile. In conclusion,we successfully developed an epigenetic-based cell engineering approach for concomitant modulation of multiple gene expressions that bypass the risks associated with DNA editing. Graphical abstract David Fenard and colleagues developed a lentiviral backbone for the multiplexing of up to three ZF-R sequences,allowing an efficient,stable,and specific epigenetic control of multiple genes in T cells or Tregs after a single lentiviral transduction event. View Publication

IntroductionSepsis engenders distinct host immunologic changes that include the expansion of myeloid-derived suppressor cells (MDSCs). These cells play a physiologic role in tempering acute inflammatory responses but can persist in patients who develop chronic critical illness.MethodsCellular Indexing of Transcriptomes and Epitopes by Sequencing and transcriptomic analysis are used to describe MDSC subpopulations based on differential gene expression,RNA velocities,and biologic process clustering.ResultsWe identify a unique lineage and differentiation pathway for MDSCs after sepsis and describe a novel MDSC subpopulation. Additionally,we report that the heterogeneous response of the myeloid compartment of blood to sepsis is dependent on clinical outcome.DiscussionThe origins and lineage of these MDSC subpopulations were previously assumed to be discrete and unidirectional; however,these cells exhibit a dynamic phenotype with considerable plasticity. View Publication

SummarySevere COVID-19 often leads to secondary infections and sepsis that contribute to long hospital stays and mortality. However,our understanding of the precise immune mechanisms driving severe complications after SARS-CoV-2 infection remains incompletely understood. Here,we provide evidence that the SARS-CoV-2 envelope (E) protein initiates innate immune inflammation,via toll-like receptor 2 signaling,and establishes a sustained state of innate immune tolerance following initial activation. Monocytes in this tolerant state exhibit reduced responsiveness to secondary stimuli,releasing lower levels of cytokines and chemokines. Mice exposed to E protein before secondary lipopolysaccharide challenge show diminished pro-inflammatory cytokine expression in the lung,indicating that E protein drives this tolerant state in vivo. These findings highlight the potential of the SARS-CoV-2 E protein to induce innate immune tolerance,contributing to long-term immune dysfunction that could lead to susceptibility to subsequent infections,and uncovers therapeutic targets aimed at restoring immune function following SARS-CoV-2 infection. Graphical abstract Highlights•SARS-CoV-2 envelope (E) protein activated innate immune cells through TLR2•E protein promoted a long-term tolerant immune state after initial activation•Monocytes in this tolerant state had reduced responsiveness to secondary stimuli•E protein priming reduced lung inflammation markers to LPS in neonatal mice Molecular biology; Immunity; Components of the immune system; Virology; Transcriptomics. View Publication

Therapeutic usage of cytokines in patients is limited by toxicity. The authors report that blocking a cytokine binding protein,IL18BP,to enhance the cytokine’s natural activity yields antitumor activity in preclinical models and shows promise for clinical translation. AbstractRecombinant cytokines have limited anticancer efficacy mostly due to a narrow therapeutic window and systemic adverse effects. IL18 is an inflammasome-induced proinflammatory cytokine,which enhances T- and NK-cell activity and stimulates IFNγ production. The activity of IL18 is naturally blocked by a high-affinity endogenous binding protein (IL18BP). IL18BP is induced in the tumor microenvironment (TME) in response to IFNγ upregulation in a negative feedback mechanism. In this study,we found that IL18 is upregulated in the TME compared with the periphery across multiple human tumors and most of it is bound to IL18BP. Bound IL18 levels were largely above the amount required for T-cell activation in vitro,implying that releasing IL18 in the TME could lead to potent T-cell activation. To restore the activity of endogenous IL18,we generated COM503,a high-affinity anti-IL18BP that blocks the IL18BP:IL18 interaction and displaces precomplexed IL18,thereby enhancing T- and NK-cell activation. In vivo,administration of a surrogate anti-IL18BP,either alone or in combination with anti-PD-L1,resulted in significant tumor growth inhibition and increased survival across multiple mouse tumor models. Moreover,the anti-IL18BP induced pronounced TME-localized immune modulation including an increase in polyfunctional nonexhausted T- and NK-cell numbers and activation. In contrast,no increase in inflammatory cytokines and lymphocyte numbers or activation state was observed in serum and spleen. Taken together,blocking IL18BP using an Ab is a promising approach to harness cytokine biology for the treatment of cancer. View Publication

BackgroundDiffuse large B-cell lymphoma (DLBCL) represents a prevalent malignant tumor,with approximately 40% of patients encountering treatment challenges or relapse attributed to rituximab resistance,primarily due to diminished or absent CD20 expression. Our prior research identified PDK4 as a key driver of rituximab resistance through its negative regulation of CD20 expression. Further investigation into PDK4’s resistance mechanism and the development of advanced exosome nanoparticle complexes may unveil novel resistance targets and pave the way for innovative,effective treatment modalities for DLBCL.MethodsWe utilized a DLBCL-resistant cell line with high PDK4 expression (SU-DHL-2/R). We infected it with short hairpin RNA (shRNA) lentivirus for RNA sequencing,aiming to identify significantly downregulated mRNA in resistant cells. Techniques including immunofluorescence,immunohistochemistry,and Western blotting were employed to determine PDK4’s localization and expression in resistant cells and its regulatory role in phosphorylation of Histone deacetylase 8 (HDAC8). Furthermore,we engineered advanced exosome nanoparticle complexes,aCD20@ExoCTX/siPDK4,through cellular,genetic,and chemical engineering methods. These nanoparticles underwent characterization via Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM),and their cellular uptake was assessed through flow cytometry. We evaluated the nanoparticles’ effects on apoptosis in DLBCL-resistant cells and immune cells using CCK-8 assays and flow cytometry. Additionally,their capacity to counteract resistance and exert anti-tumor effects was tested in a resistant DLBCL mouse model.ResultsWe found that PDK4 initiates HDAC8 activation by phosphorylating the Ser-39 site,suppressing CD20 protein expression through deacetylation. The aCD20@ExoCTX/siPDK4 nanoparticles served as effective intracellular delivery mechanisms for gene therapy and monoclonal antibodies,simultaneously inducing apoptosis in resistant DLBCL cells and triggering immunogenic cell death in tumor cells. This dual action effectively reversed the immunosuppressive tumor microenvironment,showcasing a synergistic therapeutic effect in a subcutaneous mouse tumor resistance model.ConclusionsThis study demonstrates that PDK4 contributes to rituximab resistance in DLBCL by modulating CD20 expression via HDAC8 phosphorylation. The designed exosome nanoparticles effectively overcome this resistance by targeting the PDK4/HDAC8/CD20 pathway,representing a promising approach for drug delivery and treating patients with Rituximab-resistant DLBCL.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12943-024-02057-0. View Publication

Trained immunity may play a role in vaccine-induced protection against infections. We showed that the highly efficacious recombinant VZV-gE zoster vaccine (RZV) generated trained immunity in monocytes,natural killer (NK) cells,and dendritic cells (DCs) and that the less efficacious live zoster vaccine did not. RZV stimulated ex vivo gE-specific monocyte,DC and NK cell responses that did not correlate with CD4 + T-cell responses. These responses were also elicited in purified monocyte and NK cell cocultures stimulated with VZV-gE and persisted above prevaccination levels for ≥ 4 years post-RZV administration. RZV administration also increased ex vivo heterologous monocyte and NK cell responses to herpes simplex and cytomegalovirus antigens. ATAC-seq analysis and ex vivo TGFβ1 supplementation and inhibition experiments demonstrated that decreased tgfβ1 transcription resulting from RZV-induced chromatin modifications may explain the development of monocyte trained immunity. The role of RZV-trained immunity in protection against herpes zoster and other infections should be further studied. View Publication

Current clinical strategies for the delivery of pulmonary therapeutics to the lung are primarily targeted to the upper portions of the airways. However,targeted delivery to the lower regions of the lung is necessary for the treatment of parenchymal lung injury and disease. Here,we have developed an mRNA therapeutic for the lower lung using one-component Ionizable Amphiphilic Janus Dendrimers (IAJDs) as a delivery vehicle. We deliver an anti-inflammatory cytokine mRNA,transforming growth factor-beta (TGF-β),to produce transient protein expression in the lower regions of the lung. This study highlights IAJD’s potential for precise,effective,and safe delivery of TGF-β mRNA to the lung. This delivery system offers a promising approach for targeting therapeutics to the specific tissues,a strategy necessary to fill the current clinical gap in treating parenchymal lung injury and disease. View Publication

IntroductionHumanization is typically adopted to reduce the immunogenicity of murine antibodies generated by hybridoma technology when used in humans.MethodsTwo different strategies of antibody humanization are popularly employed,including “complementarity determining region (CDR) grafting” and “framework (FR) shuffling” to humanize a murine antibody against human programmed death-1 (PD-1),XM PD1. In CDR-grafting humanization,the CDRs of XM PD-1,were grafted into the human FR regions with high homology to the murine FR counterparts,and back mutations of key residues were performed to retain the antigen-binding affinities. While in FR-shuffling humanization,a combinatorial library of the six murine CDRs in-frame of XM PD-1 was constructed to a pool of human germline FRs for high-throughput screening for the most favorable variants. We evaluated many aspects which were important during antibody development of the molecules obtained by the two methods,including antibody purity,thermal stability,binding efficacy,predicted humanness,and immunogenicity,along with T cell epitope prediction for the humanized antibodies.ResultsWhile the ideal molecule was not achieved through CDR grafting in this particular instance,FR-shuffling proved successful in identifying a suitable candidate. The study highlights FR-shuffling as an effective complementary approach that potentially increases the success rate of antibody humanization. It is particularly noted for its accessibility to those with a biological rather than a computational background. DiscussionThe insights from this comparison are intended to assist other researchers in selecting appropriate humanization strategies for drug development,contributing to broader application and understanding in the field. View Publication

IntroductionHeme oxygenase-1 (HO-1) is a stress-inducible heat shock protein (HSP32) that exerts cytoprotective effects against oxidative stress and inflammation,and is involved in the maintenance of cellular homeostasis. This study aimed to evaluate the expression of HO-1 in natural killer (NK) cells from individuals of different age groups after stimulation with various factors,and to analyze the relationships between the concentration of this cytoprotective protein and parameters corresponding to oxidative stress and inflammation,that is,NOD-like receptor protein 3 (NLRP3),glutathione (GSH),GSH disulfide (GSSG),and interleukin 6 (IL-6).MethodsThe study population comprised three age groups: young adults (age range,19–23 years),older adults aged under 85 years (age range,73–84 years),and older adults aged over 85 years (age range,85–92 years). NLRP3,GSH,and GSSG concentrations were measured in serum,whereas the HO-1 concentration and IL-6 expression were studied in NK cells cultivated for 48 h and stimulated with IL-2,lipopolysaccharide (LPS),or phorbol 12-myristate 13-acetate (PMA) with ionomycin.ResultsThe analysis of serum NLRP3,GSH,and GSSG concentrations revealed no statistically significant differences among the studied age groups. However,some typical trends of aging were observed,such as a decrease in GSH concentration and an increase in both GSSG level,and GSSG/GSH ratio. The highest basal expression of IL-6 and lowest basal content of HO-1 were found in NK cells of adults over 85 years of age. The NK cells in this age group also showed the highest sensitivity to stimulation with the applied factors. Moreover,statistically significant negative correlations were observed between HO-1 and IL-6 expression levels in the studied NK cells.ConclusionsThese results showed that NK cells can express HO-1 at a basal level,which was significantly increased in activated cells,even in the oldest group of adults. The reciprocal relationship between HO-1 and IL-6 expression suggests a negative feedback loop between these parameters. View Publication

AbstractIntroductionNovel strategies are needed to address the rising burden of osteoporosis and fragility fractures. High-intensity resistance and impact (HiRIT) exercise has shown benefit in improving bone density in postmenopausal women with osteoporosis/osteopenia. Whether HiRIT can enhance the therapeutic effects of osteoporosis pharmacotherapy has not been established. ROLEX-DUO is a randomised controlled trial designed to assess the efficacy of romosozumab on various bone and muscle outcomes in combination with different exercise interventions in women with postmenopausal osteoporosis/osteopenia.Methods and analysisROLEX-DUO is an 8-month randomised placebo-controlled trial conducted at two tertiary referral centres for patients with osteoporosis/osteopenia in Sydney,New South Wales,Australia. The study is implementing the combination of romosozumab or placebo with different forms of exercise in postmenopausal women with osteoporosis/osteopenia without recent fragility fracture (n=102). Eligible women will be randomised 1:1:1 into one of three groups: (1) romosozumab with supervised HiRIT,(2) romosozumab with unsupervised low-intensity exercise or (3) placebo with unsupervised low-intensity exercise. Co-primary outcomes are the mean percentage change in lumbar spine bone mineral density (BMD),and mean change in five times sit-to-stand test performance (seconds) at 8 months. Secondary/exploratory outcomes include BMD changes at the femoral neck,total hip and distal radius,three-dimensional dual-energy X-ray absorptiometry (DXA) hip outcomes,DXA-derived lean and fat mass,serum markers of bone turnover (procollagen type 1 peptide,C-telopeptide of type 1 collagen) and bone biomarkers (dickkopf-1),serum extracellular vesicle analyses,36-Item Short Form Survey (SF-36) quality-of-life scores,Menopause-Specific Quality Of Life (MENQOL) Questionnaire menopause symptom burden scores,number of falls and fractures. Mixed-effects models will be performed to compare longitudinal outcome results between groups using intention-to-treat analysis.Ethics and disseminationThe trial was approved by the Northern Sydney Local Health District Human Research Ethics Committee (2022/ETH01794,protocol V.8,dated 03 July 2024). Participants will provide written informed consent prior to inclusion. Findings will be disseminated via peer-reviewed journals,scientific conferences and summary reports to funding bodies.Trial registration numberACTRN12623000867695. View Publication

Single-cell RNA sequencing (scRNA-seq) can resolve transcriptional features from individual cells,but scRNA-seq techniques capable of resolving the variable regions of B cell receptors (BCRs) remain limited,especially from widely-used 3′-barcoded libraries. Here,we report a method that can recover paired,full-length variable region sequences of BCRs from 3′-barcoded scRNA-seq libraries. We first verify this method (B3E-seq) can produce accurate,full-length BCR sequences. We then apply this method to profile B cell responses elicited against the capsular polysaccharide of Streptococcus pneumoniae serotype 3 (ST3) by glycoconjugate vaccines in five infant rhesus macaques. We identify BCR features associated with specificity for the ST3 antigen which are present in multiple vaccinated monkeys,indicating a convergent response to vaccination. These results demonstrate the utility of our method to resolve key features of the B cell repertoire and profile antigen-specific responses elicited by vaccination. A method that recovers full-length,paired heavy- and light-chain variable regions of B cell receptor transcripts from 3’barcoded scRNA-seq libraries reveals a convergent response to pneumococcus vaccination in rhesus macaques. View Publication