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AbstractBackgroundNatural killer (NK) cells’ unique ability to kill transformed cells expressing stress ligands or lacking major histocompatibility complexes (MHC) has prompted their development for immunotherapy. However,NK cells have demonstrated only moderate responses against cancer in clinical trials.MethodsAdvanced genome engineering may thus be used to unlock their full potential. Multiplex genome editing with CRISPR/Cas9 base editors (BEs) has been used to enhance T cell function and has already entered clinical trials but has not been reported in human NK cells. Here,we report the first application of BE in primary NK cells to achieve both loss-of-function and gain-of-function mutations.ResultsWe observed highly efficient single and multiplex base editing,resulting in significantly enhanced NK cell function in vitro and in vivo. Next,we combined multiplex BE with non-viral TcBuster transposon-based integration to generate interleukin-15 armored CD19 chimeric antigen receptor (CAR)-NK cells with significantly improved functionality in a highly suppressive model of Burkitt’s lymphoma both in vitro and in vivo.ConclusionsThe use of concomitant non-viral transposon engineering with multiplex base editing thus represents a highly versatile and efficient platform to generate CAR-NK products for cell-based immunotherapy and affords the flexibility to tailor multiple gene edits to maximize the effectiveness of the therapy for the cancer type being treated. View Publication

IntroductionCurrent antiretroviral therapy (ART) for HIV infection reduces plasma viral loads to undetectable levels and has increased the life expectancy of people with HIV (PWH). However,this increased lifespan is accompanied by signs of accelerated aging and a higher prevalence of age-related comorbidities. Tat (Trans-Activator of Transcription) is a key protein for viral replication and pathogenesis. Tat is encoded by 2 exons,with the full-length Tat ranging from 86 to 101 aa (Tat101). Introducing a stop codon in position 73 generates a 1 exon,synthetic 72aa Tat (Tat72). Intracellular,full-length Tat activates the NF-κB pro-inflammatory pathway and increases antiapoptotic signals and ROS generation. These effects may initiate a cellular senescence program,characterized by cell cycle arrest,altered cell metabolism,and increased senescence-associated secretory phenotype (SASP) mediator release However,the precise role of HIV-Tat in inducing a cellular senescence program in CD4+ T-cells is currently unknown.MethodsJurkat Tetoff cell lines stably transfected with Tat72,Tat101,or an empty vector were used. Flow cytometry and RT-qPCR were used to address senescence biomarkers,and 105 mediators were assessed in cell supernatants with an antibody-based membrane array. Key results obtained in Jurkat-Tat cells were addressed in primary,resting CD4+ T-cells by transient electroporation of HIV-Tat-FLAG plasmid DNA.ResultsIn the Jurkat cell model,expression of Tat101 increased the levels of the senescence biomarkers BCL-2,CD87,and p21,and increased the release of sCD30,PDGF-AA,and sCD31,among other factors. Tat101 upregulated CD30 and CD31 co-expression in the Jurkat cell surface,distinguishing these cells from Tat72 and Tetoff Jurkats. The percentage of p21+,p16+,and γ-H2AX+ cells were higher in Tat-expressing CD4+ T-cells,detected as a FLAG+ population compared to their FLAG- (Tat negative) counterparts. Increased levels of sCD31 and sCD26 were also detected in electroporated CD4+ T-cell supernatants.DiscussionIntracellular,full-length HIV-Tat expression increases several senescence biomarkers in Jurkat and CD4+ T-cells,and SASP/Aging mediators in cell supernatants. Intracellular HIV-Tat may initiate a cellular senescence program,contributing to the premature aging phenotype observed in PWH. Graphical Abstract View Publication

Tetracyclines are essential bacterial protein synthesis inhibitors under continual development to combat antibiotic resistance yet suffer from unwanted side effects. Mitoribosomes - responsible for generating oxidative phosphorylation (OXPHOS) subunits - share structural similarities with bacterial machinery and may suffer from cross-reactivity. Since lymphocytes rely upon OXPHOS upregulation to establish immunity,we set out to assess the impact of ribosome-targeting antibiotics on human T cells. We find tigecycline,a third-generation tetracycline,to be the most cytotoxic compound tested. In vitro,5–10 μM tigecycline inhibits mitochondrial but not cytosolic translation,mitochondrial complex I,III and IV expression,and curtails the activation and expansion of unique T cell subsets. By cryo-EM,we find tigecycline to occupy three sites on T cell mitoribosomes. In addition to the conserved A-site found in bacteria,tigecycline also attaches to the peptidyl transferase center of the large subunit. Furthermore,a third,distinct binding site on the large subunit,aligns with helices analogous to those in bacteria,albeit lacking methylation in humans. The data provide a mechanism to explain part of the anti-inflammatory effects of these drugs and inform antibiotic design. Tetracyclines impair cellular function by targeting ribosomes. Here,the authors demonstrate that tigecycline impairs T cell function by selectively inhibiting mitochondrial protein synthesis and uncover the structural basis for mitoribosome inhibition and its role in immunosuppression. View Publication

Squalene-based emulsion (SE) adjuvants like MF59 and AS03 are used in protein subunit vaccines against influenza virus (e.g.,Fluad,Pandemrix,Arepanrix) and SARS-CoV-2 (e.g.,Covifenz,SKYCovione). We demonstrate the critical role of uric acid (UA),a damage-associated molecular pattern (DAMP),in triggering immunogenicity by SE adjuvants. In mice,SE adjuvants elevated DAMP levels in draining lymph nodes. Strikingly,inhibition of UA synthesis reduced vaccine-induced innate immunity,subsequently impairing optimal antibody and T cell responses. In vivo treatment with UA crystals elicited partial adjuvant effects. In vitro stimulation with UA crystals augmented the activation of dendritic cells (DCs) and B cells and altered multiple pathways in these cells,including inflammation and antigen presentation in DCs and cell proliferation in B cells. In an influenza vaccine model,UA contributed to protection against influenza viral infection. These results demonstrate the importance of DAMPs,specifically the versatile role of UA in the immunogenicity of SE adjuvants,by regulating DCs and B cells. View Publication

Extracellular DNA (eDNA) is crucial for the structural integrity of bacterial biofilms as they undergo transformation from B-DNA to Z-DNA as the biofilm matures. This transition to Z-DNA increases biofilm rigidity and prevents binding by canonical B-DNA-binding proteins,including nucleases. One of the primary defenses against bacterial infections are Neutrophil Extracellular Traps (NETs),wherein neutrophils release their own eDNA to trap and kill bacteria. Here we show that H-NS,a bacterial nucleoid associated protein (NAP) that is also released during biofilm development,is able to incapacitate NETs. Indeed,when exposed to human derived neutrophils,H-NS prevented the formation of NETs and lead to NET eDNA retraction in previously formed NETs. NETs that were exposed to H-NS also lost their ability to kill free-living bacteria which made H-NS an attractive therapeutic candidate for the control of NET-related human diseases. A model of H-NS release from biofilms and NET incapacitation is discussed. View Publication

Myocardial infarction (MI) is a major global health concern. Although myeloid cells are crucial for tissue repair in emergency haematopoiesis after MI,excessive myelopoiesis can exacerbate scarring and impair cardiac function. Bone marrow (BM) haematopoietic stem cells (HSCs) have the unique capability to replenish the haematopoietic system,but their role in emergency haematopoiesis after MI has not yet been established. Here we collected human sternal BM samples from over 150 cardiac surgery patients,selecting 49 with preserved cardiac function. We show that MI causes detrimental transcriptional and functional changes in human BM HSCs. Lineage tracing experiments suggest that HSCs are contributors of pro-inflammatory myeloid cells infiltrating cardiac tissue after MI. Therapeutically,enforcing HSC quiescence with the vitamin A metabolite 4-oxo-retinoic acid dampens inflammatory myelopoiesis,thereby modulating tissue remodelling and preserving long-term cardiac function after MI. Rettkowski,Romero-Mulero et al. show that myocardial infarction impacts bone marrow haematopoietic stem cells and leads to inflammatory myelopoiesis,which can be dampened by treatment with 4-oxo-retinoic acid,promoting cardiac recovery. View Publication

AbstractBackgroundChimeric antigen receptor (CAR) T-cell therapy depends on T cells that are genetically modified to recognize and attack cancer cells. Their effectiveness thus hinges on the functionality of a patient’s own T cells. Since CAR T-cell therapy is currently only approved for advanced cancers after at least one line of chemotherapy,we evaluated the potential negative effects of prior exposure to chemotherapy on T-cell functionality.MethodsWe studied T cells of two B-cell non-Hodgkin’s lymphoma patient cohorts,one collected before treatment (pre-therapy) and the other after one or more (median 3) lines of chemotherapy (post-therapy). Leveraging advanced multiparameter flow cytometry,single-cell RNA sequencing (scRNA-seq),whole-genome DNA methylation arrays and in vitro functionality testing of generated CAR T cells,we compared patient samples in their suitability for effective CAR T-cell therapy.ResultsWe discovered significant modifications in T-cell subsets and their transcriptional profiles secondary to chemotherapy exposure. Our analysis revealed a discernible shift towards phenotypically more differentiated T cells and an upregulation of markers indicative of T-cell exhaustion. Additionally,scRNA-seq and DNA methylation analyses revealed gene expression and epigenetic changes associated with diminished functionality in post-therapy T cells. Cytotoxicity assays demonstrated superior killing efficacy of CAR T cells derived from treatment-naïve patients compared with those with chemotherapy history.ConclusionsThese findings corroborate that employing T cells collected prior to frontline chemotherapy could enhance the effectiveness of CAR T-cell therapy and improve patient outcomes. View Publication

AbstractThere is currently a lack of tools capable of perturbing genes in both a precise and a spatiotemporal fashion. The flexibility of CRISPR (clustered regularly interspaced short palindromic repeats),coupled with light’s unparalleled spatiotemporal resolution deliverable from a controllable source,makes optogenetic CRISPR a well-suited solution for precise spatiotemporal gene perturbations. Here,we present a new optogenetic CRISPR tool (Blue Light-inducible Universal VPR-Improved Production of RGRs,BLU-VIPR) that diverges from prevailing split-Cas design strategies and instead focuses on optogenetic regulation of guide RNA (gRNA) production. We engineered BLU-VIPR around a new potent blue-light activated transcription factor (VPR-EL222) and ribozyme-flanked gRNA. The BLU-VIPR design is genetically encoded and ensures precise excision of multiple gRNAs from a single messenger RNA transcript. This simplified spatiotemporal gene perturbation and allowed for several types of optogenetic CRISPR,including indels,CRISPRa,and base editing. BLU-VIPR also worked in vivo with cells previously intractable to optogenetic gene editing,achieving optogenetic gene editing in T lymphocytes in vivo. View Publication

Data of low-density neutrophils (LDN),the neutrophils in the peripheral blood mononuclear cells (PBMC) fraction,in sepsis is still less. As such,LDN (CD66b-positive cells in PBMC) was highest in intensive care unit (ICU) patients with sepsis (n=24) compared with non-sepsis (n=10) and healthy control (n=20),with a negative correlation with lymphocyte count and could predict secondary infection and mortality with the area under the curve (AUC) at 0.79 and 0.84,respectively. Compared with sepsis normal-density neutrophils (NDN),sepsis-LDN demonstrated higher expression of CD66b,CD63,CD11b,and CD184,but lower expression of CD62L and CD182 and defects of effector functions,including phagocytosis and apoptosis. The t-distributed stochastic neighbor embedding (t-SNEs) demonstrated high program cell death ligand-1 (PD-L1) in sepsis-LDN. In sepsis samples,the T cell proliferation in PBMC (T cells with LDNs) was lower than that in the isolated T cells (T cells alone) and incubation of anti-PD-L1 neutralizing antibody,but not a reactive oxygen species (ROS) scavenger (N-acetyl cysteine),improved the T cell suppression. Additionally,30 min lipopolysaccharide (LPS) activation altered healthy control NDN into LPS-LDN (reduced density) and LPS-NDN (maintain density) with similarly elevated CD66b,CD11B,and CD62L. However,LPS-LDN (in vitro LDN) showed lower expression of CD63,CD184,and PD-L1 compared with LDN from patients (sepsis-LDN),suggesting a partial LPS impact on LDN generation. From the microscopic-based method (Wright’s staining in PBMC),sepsis-LDN demonstrated a mixed population of mature and immature cells with a good correlation with the flow-based analysis (Bland–Altman analysis and AUC). In conclusion,LDN in sepsis,partly generated by LPS activation,was associated with secondary infection and T cell suppression,mainly through the expression of PD-L1,which might be an immune suppression biomarker,especially with a less expensive microscopic-based method. View Publication

This work demonstrates that group 2 KLF family transcription factors are critical for specifying the identity of distinct tissue-resident macrophages. KLF2 directly controls expression of genes previously shown to be necessary in cavity macrophages,while KLF4 may play a similar role in alveolar macrophages. Tissue-resident macrophages adopt distinct gene expression profiles and exhibit functional specialization based on their tissue of residence. Recent studies have begun to define the signals and transcription factors that induce these identities. Here we describe an unexpected and specific role for the broadly expressed transcription factor Krüppel-like factor 2 (KLF2) in the development of embryonically derived large cavity macrophages (LCMs) in the serous cavities. KLF2 not only directly regulates the transcription of genes previously shown to specify LCM identity,such as retinoic acid receptors and GATA6,but also is required for induction of many other transcripts that define the identity of these cells. Our results suggest that KLF4 may similarly regulate the identity of alveolar macrophages in the lung. These data demonstrate that broadly expressed transcription factors,such as group 2 KLFs,can play important roles in the specification of distinct identities of tissue-resident macrophages. View Publication

Uveal melanoma (UM) is the most common intraocular cancer in adults,with metastatic disease (mUM) occurring in approximately half of the patients. Tebentafusp,an immune-mobilizing monoclonal T cell receptor against cancer (ImmTAC),is a therapeutic shown to improve overall survival (OS) in HLA-A*02:01+ adult patients with mUM. Here we investigate the impact of tumor-associated macrophages (TAM) on ImmTAC activity. In vitro,M2 macrophages inhibit ImmTAC-mediated tumor-killing in a dose-dependent and contact-dependent manner. Accordingly,high baseline intratumoral TAM-to-T cell ratios correlate with shorter OS (HR = 2.09,95% CI,1.31–3.33,p = 0.002) in tebentafusp-treated mUM patients from a phase 2 trial. By contrast,IL-2 conditioning of T cells overcomes M2 macrophage-mediated suppression in vitro,while ImmTAC treatment leads to M2-to-M1 macrophage reprogramming both in vitro and in tebentafusp-treated mUM patients. Overall,we show that tebentafusp reshapes the tumor microenvironment to enhance anti-tumor T cell activity,whilst combining tebentafusp with IL-2 may enhance benefit in patients with high levels of TAM. ‘T cell engagers promote antitumor immunity,but how macrophage modulates this activity in tumor is still unclear. Here the authors show,using biopsies from patients with uveal melanoma and single cell analyses,that a T cell engager,tebentafusp,reprograms tumor-associated macrophages and ameliorates,in synergy with IL-2,immunosuppression to cancer. View Publication

AbstractBackgroundHypoxia is associated with the evasion of triple-negative breast cancer (TNBC) from immune surveillance. Hypoxia increases the subpopulation of putative TNBC stem-like cells (TNBCSCs) through activating Wnt/β-Catenin signaling. The shedding of MHC class I-related chain A (MICA) is particularly noteworthy in cancer stem cells (CSCs),promoting the resistance of CSCs to natural killer (NK) cell cytotoxicity. To reestablish MICA/NKG2D-mediated immunosurveillance,we proposed the design of a fusion protein (SHH002-hu1-MICA) which consists of Frizzled-7 (Fzd7)-targeting antibody and MICA,serving as an engager retargeting NK cells against TNBCs,especially TNBCSCs.MethodsOpal multicolor immunohistochemistry staining was used to validate the expression of membrane MICA (mMICA) and existence of NK cells in TNBC tumors; flow cytometry (FCM) assay was used to detect the expression of Fzd7/mMICA on TNBCs. Biolayer interferometry (BLI) and surface plasmon resonance (SPR) assays were executed to assess the affinity of SHH002-hu1-MICA towards rhFzd7/rhNKG2D; near-infrared imaging assay was used to evaluate the targeting capability. A cytotoxicity assay was conducted to assess the effects of SHH002-hu1-MICA on NK cell-mediated killing of TNBCs,and FCM assay to analyze the effects of SHH002-hu1-MICA on the degranulation of NK cells. Finally,TNBC cell-line-derived xenografts were established to evaluate the anti-tumor activities of SHH002-hu1-MICA in vivo.ResultsThe expression of mMICA is significantly downregulated in hypoxic TNBCs and TNBCSCs,leading to the evasion of immune surveillance exerted by NK cells. The expression of Fzd7 is significantly upregulated in TNBCSCs and exhibits a negative correlation with the expression of mMICA and infiltration level of NK cells. On accurate assembly,SHH002-hu1-MICA shows a strong affinity for rhFzd7/rhNKG2D,specifically targets TNBC tumor tissues,and disrupts Wnt/β-Catenin signaling. SHH002-hu1-MICA significantly enhances the cytotoxicity of NK cells against hypoxic TNBCs and TNBCSCs by inducing the degranulation of NK cells and promotes the infiltration of NK cells in CD44high regions within TNBC xenograft tumors,exhibiting superior anti-tumor activities than SHH002-hu1.ConclusionsSHH002-hu1-MICA maintains the targeting property of SHH002-hu1,successfully activates and retargets NK cells against TNBCs,especially TNBCSCs,exhibiting superior antitumor activities than SHH002-hu1. SHH002-hu1-MICA represents a promising new engager for NK cell-based immunotherapy for TNBC. View Publication