WDFY4 is required for cross-presentation in response to viral and tumor antigens

Potential targets for synergistic bipolar irreversible electroporation in tumor suppression through transcriptomics and proteomics analysis

Previous studies have demonstrated that synergistic bipolar irreversible electroporation (SBIRE) is a promising non-thermal tumor ablation technique that effectively targets tumors without causing muscle contractions. Despite its clinical potential, the mechanistic understanding of SBIRE's tumor-suppressive effects remains underexplored. This study aims to identify potential molecular targets for SBIRE-mediated tumor suppression through comprehensive transcriptomics and proteomics analyses. Mice were selected as subjects for the creation of tumor models by the subcutaneous tumor-bearing method. Following the SBIRE intervention, tumor surveillance and pathological investigations were carried out. A comprehensive investigation was conducted using RNA sequencing-based transcriptomics and label-free quantitative proteomics to examine normal and SBIRE treated tumor samples. Differentially expressed genes (DEGs) and crucial signaling pathways were found using bioinformatics analysis. Western blot (WB), immunohistochemistry (IHC), and quantitative real-time PCR (qRT-PCR) were used to validate potentially associated genes. The results demonstrate that a substantial reduction in tumor size was achieved following SBIRE treatment. A total of 86 genes exhibited differential expression in tumors, with 84 genes showing upregulation and 2 genes showing downregulation. According to bioinformatics research, these DEGs were involved in a wide variety of biological activities, such as cell adhesion, positive regulation of tumor necrosis factor production, and immune system process. Beside major enrichment pathways like Efferocytosis, Endocytosis, PPAR signaling pathway and Metabolic pathways. The upregulation of WDFY family member 4 (WDFY4), Thrombospondin 1(THBS1), Pentraxin 3 (PTX3), Superoxide dismutase 3 (SOD3) and Glutathione peroxidase 3 (GPX3) genes were confirmed. These insights into the molecular underpinnings of SBIRE offer a novel therapeutic strategy for enhancing tumor suppression and improving clinical outcomes in cancer treatment.

Enhancing antitumor immunity through chemotherapeutic-derived lipid nanoparticle-induced immunogenic cell death and CD40L/Flt3L mRNA-mediated dendritic cell activation

Dendritic cells (DCs) are essential for inducing effective antitumor T cell responses. However, the immunosuppressive tumor microenvironment (TME) hinders DC recruitment and maturation, facilitating tumor progression and spread. This study investigates the synergistic potential of immunogenic cell death (ICD), triggered by chemotherapeutic-derived lipid nanoparticles (LNPs), in combination with Flt3L and CD40L mRNA delivery to enhance DC mobilization and activation, reprogram the TME, and ultimately promote robust antitumor T cell responses. The optimized LNP formulation, GEM5Q7, efficiently delivered mRNA and induced ICD in melanoma cells. Intratumoral administration of GEM5Q7, encapsulating Flt3L and CD40L mRNAs, elevated pro-inflammatory cytokine and chemokine secretion, driving the infiltration and activation of cross-presenting DCs, which are critical for priming T cells. In a subcutaneous melanoma model, this approach led to significant tumor suppression and a 40 % complete response rate. This strategy holds promise for enhancing cancer immunotherapies by reprogramming the TME and inducing durable antitumor T cell immunity.

STAT5 and STAT3 balance shapes dendritic cell function and tumour immunity

Immune checkpoint blockade (ICB) has transformed cancer therapy1,2. The efficacy of immunotherapy depends on dendritic cell-mediated tumour antigen presentation, T cell priming and activation3,4. However, the relationship between the key transcription factors in dendritic cells and ICB efficacy remains unknown. Here we found that ICB reprograms the interplay between the STAT3 and STAT5 transcriptional pathways in dendritic cells, thereby activating T cell immunity and enabling ICB efficacy. Mechanistically, STAT3 restrained the JAK2 and STAT5 transcriptional pathway, determining the fate of dendritic cell function. As STAT3 is often activated in the tumour microenvironment5, we developed two distinct PROTAC (proteolysis-targeting chimera) degraders of STAT3, SD-36 and SD-2301. STAT3 degraders effectively degraded STAT3 in dendritic cells and reprogrammed the dendritic cell-transcriptional network towards immunogenicity. Furthermore, STAT3 degrader monotherapy was efficacious in treatment of advanced tumours and ICB-resistant tumours without toxicity in mice. Thus, the crosstalk between STAT3 and STAT5 transcriptional pathways determines the dendritic cell phenotype in the tumour microenvironment and STAT3 degraders hold promise for cancer immunotherapy.

Regulatory T cell depletion promotes myeloid cell activation and glioblastoma response to anti-PD1 and tumor-targeting antibodies

Glioblastoma is invariably lethal and responds poorly to immune checkpoint blockade. Here, we examined the impact of regulatory T (Treg) cell depletion on glioblastoma progression and immunotherapy responsiveness. In human glioblastoma, elevated Treg cell signatures correlated with poorer survival outcomes, with these cells expressing high levels of CD25. In Nf1-/-Pten-/-EGFRvIII+ glioblastoma-bearing mice, a single dose of non-interleukin-2 (IL-2) blocking (NIB) anti-CD25 (anti-CD25NIB) antibody depleted Treg cells and promoted CD8+ T cell clonal expansion and partial tumor control, further enhanced by programmed cell death-1 (PD1)-blockade. Treg cell depletion induced interferon-γ (IFN-γ)-dependent tumor microenvironment remodeling, increasing Fcγ receptor (FcγR) expression on intratumoral myeloid cells and enhancing phagocytosis. Combination of anti-CD25NIB with anti-EGFRvIII tumor-targeting antibodies resulted in complete tumor control. Anti-human CD25NIB treatment of glioblastoma patient-derived tumor fragments effectively depleted Treg cells and activated CD8+ T cells. These findings underscore the therapeutic relevance of Treg targeting in glioblastoma and unveil potent combination strategies for anti-CD25NIB based on innate cell activation.

Anti- Melanoma Differentiation-Associated Gene 5 Antibody Positive Dermatomyositis: Recent Progress in Pathophysiology and Treatment

PURPOSE OF REVIEW

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is a rare systemic autoimmune disease characterized by a clinically amyopathic presentation and a high-risk association with rapidly progressive interstitial lung disease. Although frequently fatal, the underlying mechanisms remain incompletely understood. This review provides a comprehensive summary of recent advances in research on MDA5-DM, aiming to deepen our understanding of its pathogenic mechanisms and to accelerate future basic research that will contribute to the development of novel therapeutic strategies.

RECENT FINDINGS

Recent advancements have shed light on various aspects of this disease, including genetic and environmental factors contributing to disease susceptibility and the immunopathological processes and cytokine networks. Furthermore, significant progress has been made in understanding the pathogenicity, epitope recognition, and production mechanisms of anti-MDA5 antibodies, which have long been subjects of debate. On the therapeutic front, in addition to the conventional triple-combination regimen, emerging efficacy of JAK inhibitors and rituximab has been recognized. The development of biologics targeting lymphocytes offers additional hope for advancing therapeutic options. Advancing our understanding of the latest pathophysiological mechanisms of MDA5-DM is expected to pave the way for the development of safer and more effective therapeutic strategies.

The winding road to platelet α-granules

Platelets are anucleate cellular fragments derived from megakaryocytes (MKs) and α-granules constitute their most numerous membrane-bound compartments. These granules play a role in platelet aggregation to form a hemostatic plug but also contain numerous cargo proteins with key functions in angiogenesis, inflammation, wound healing and cancer. Human genetic disorders that cause deficiencies in the biogenesis of platelet α-granules manifest with prolonged bleeding. The initial studies on platelets and MKs from these patients provided a first glimpse into the biosynthesis of α-granules as a membrane trafficking problem. Significant progress in the field has been made in recent years in part due to the creation of iPSC-derived megakaryocytic cells capable of releasing functional platelets, thus overcoming the limitations of working with primary MKs. The emerging model indicates that sorting and recycling endosomes are key intermediate stations traversed by α-granule cargo on their way to the α-granule. Here we describe the different trafficking pathways used by α-granule proteins and elaborate on their commonalities. Similar to other lysosome-related organelles, most of the proteins involved in the biogenesis of α-granules are ubiquitously expressed and we discuss NBEAL2 as a factor highly expressed in MKs that likely diverts this machinery to make α-granules. Importantly, understanding the trafficking pathways involved in the making of the α-granule has an impact not only on platelet biology but may also illuminate the broader lysosome-related organelle field.

Metallophilic marginal zone macrophages cross-prime CD8+ T cell-mediated protective immunity against blood-borne tumors

Splenic metallophilic marginal zone macrophages (MMMs) are positioned to control the dissemination of blood-borne threats. We developed a purification protocol to enable characterization of MMMs phenotypically and transcriptionally. MMM gene expression profile was enriched for pathways associated with CD8+ T cell activation and major histocompatibility complex class I (MHC class I) cross-presentation. In vitro, purified MMMs equaled conventional dendritic cells type 1 (cDC1s) in cross-priming CD8+ T cells to soluble and particulate antigens, yet MMMs employed a distinct vacuolar processing pathway. In vivo biphoton and ex vivo light-sheet imaging showed long-standing contacts with cognate T cells differentiating to effectors. MMMs cross-primed protective CD8+ T cell antitumor responses both by capturing blood-borne tumor antigens and by internalizing tumor cells seeding the spleen. This cross-priming required expression of the transcription factor Batf3 by MMMs but was independent of cDC1-mediated capture of tumor material for cross-presentation or MHC class I-dressing. Thus, MMMs combine control of the dissemination of blood-borne pathogens and tumor materials with the initiation of innate and adaptive responses.

Shared pathway of WDFY4-dependent cross-presentation of immune complexes by cDC1 and cDC2

Priming CD8+ T cells against tumors or viral pathogens results largely from cross-presentation of exogenous antigens by type 1 conventional dendritic cells (cDC1s). Although monocyte-derived DCs and cDC2s can cross-present in vitro, their physiological relevance remains unclear. Here, we used genetic models to evaluate the role of cDC subsets in presentation of cell-associated and immune complex antigens to CD4+ and CD8+ T cells in vivo. For cell-associated antigens, cDC1s were necessary and sufficient to prime both CD4+ and CD8+ T cells. In contrast, for immune complex antigens, either cDC1 or cDC2, but not monocyte-derived DCs, could carry out cross-presentation to CD8+ T cells. Mice lacking cDC1 and vaccinated with immune complexes could cross-prime CD8+ T cells that were sufficient to mediate tumor rejection. Notably, this cross-presentation mediated by cDC2 was also WDFY4 dependent, similar to cross-presentation of cell-associated antigens by cDC1. These results demonstrate a previously unrecognized activity of WDFY4 in cDC2s and suggest a cross-presentation pathway shared by cDC subsets.

Cross-priming in cancer immunology and immunotherapy

Cytotoxic T cell immune responses against cancer crucially depend on the ability of a subtype of professional antigen-presenting cells termed conventional type 1 dendritic cells (cDC1s) to cross-present antigens. Cross-presentation comprises redirection of exogenous antigens taken from other cells to the major histocompatibility complex class I antigen-presenting machinery. In addition, once activated and having sensed viral moieties or T helper cell cooperation via CD40-CD40L interactions, cDC1s provide key co-stimulatory ligands and cytokines to mount and sustain CD8+ T cell immune responses. This regulated process of cognate T cell activation is termed cross-priming. In cancer mouse models, CD8+ T cell cross-priming by cDC1s is crucial for the efficacy of most, if not all, immunotherapy strategies. In patients with cancer, the presence and abundance of cDC1s in the tumour microenvironment is markedly associated with the level of T cell infiltration and responsiveness to immune checkpoint inhibitors. Therapeutic strategies to increase the numbers of cDC1s using FMS-like tyrosine kinase 3 ligand (FLT3L) and/or their activation status show evidence of efficacy in cancer mouse models and are currently being tested in initial clinical trials with promising results so far.

Tissue-specific properties of type 1 dendritic cells in lung cancer: implications for immunotherapy

Checkpoint inhibitors have led to remarkable benefits in non-small cell lung cancer (NSCLC), yet response rates remain below expectations. High-dimensional analysis and mechanistic experiments in clinical samples and relevant NSCLC models uncovered the immune composition of lung cancer tissues, providing invaluable insights into the functional properties of tumor-infiltrating T cells and myeloid cells. Among myeloid cells, type 1 conventional dendritic cells (cDC1s) stand out for their unique ability to induce effector CD8 T cells against neoantigens and coordinate antitumoral immunity. Notably, lung resident cDC1 are particularly abundant and long-lived and express a unique tissue-specific gene program, underscoring their central role in lung immunity. Here, we discuss recent insights on the induction and regulation of antitumoral T cell responses in lung cancer, separating it from the tissue-agnostic knowledge generated from heterogeneous tumor models. We focus on the most recent studies dissecting functional states and spatial distribution of lung cDC1 across tumor stages and their impact on T cell responses to neoantigens. Finally, we highlight relevant gaps and emerging strategies to harness lung cDC1 immunostimulatory potential.

New insights into markers for distinguishing neuroendocrine prostate cancer: evidence from single-cell analysis

Background

Neuroendocrine prostate cancer (NEPC) is a highly aggressive malignancy with few effective treatment options. The identification of reliable biomarkers for NEPC is essential for early detection and intervention.

Methods

We combined single-cell and bulk transcriptome analysis to identify novel markers of NEPC. InferCNV to assess copy number variations and leveraging consensus non-negative matrix factorization (cNMF) to characterize transcriptional programs. Pseudotime analysis was used to decipher prostate cancer (PCa) progression differentiation trajectory. BayesPrism integrates single-cell results and TCGA-PRAD sequencing information to further study prognostic features. Immunohistochemistry (IHC) was performed to validate the elevated expression of ASCL1 and WDFY4 in NEPC.

Results

We identified five distinct expression programs of PCa malignant epithelial cells, where Module 3 presented NEPC expression patterns, with activation of DNA replication and cell cycle pathways and classical NEPC marker expression. Patients with high Module 3 proportion correlated to poor clinical outcomes, advanced Gleason scores, and higher T stages. Pseudotime analysis highlighted key trajectory-dependent genes involved in the transition to NEPC, where expression of ASCL1 and WDFY4 elevated with progressing to NEPC cell fate, which were further confirmed by IHC analysis, indicating that WDFY4 and ASCL1 might be novel potential markers for distinguishing NEPC.

Conclusions

Combined single-cell and bulk analysis, we highlight the cellular heterogeneity and transcriptional programs, validated novel biomarkers of NEPC. Providing a foundation for early prediction of NEPC and management.

Revolutionizing cancer treatment: The power of dendritic cell-based vaccines in immunotherapy

In the modern time, cancer immunotherapies have increasingly become vital treatment options, joining long-established methods like surgery, chemotherapy, and radiotherapy treatment. Central to this emerging approach are dendritic cells (DCs), which boast a remarkable ability for antigen presentation. This ability is being leveraged to modulate T and B cell immunity, offering a groundbreaking strategy for tackling cancer. However, the percentage of patients experiencing meaningful benefits from this treatment remains relatively low, underscoring the ongoing necessity for further research and development in this field. This review offers a comprehensive analysis of the present-day progress in dendritic cell (DC)-based vaccines and recent efforts to enhance their efficacy. We explore the intricacies of DC function, from antigen capture to T cell stimulation, and discuss the outcomes of both preclinical and clinical trials across various cancer types. While the results are promising, the real-world application of DC-based vaccines is still nascent, posing multiple challenges that need to be overcome. These obstacles include optimizing the methods for DC generation and antigen loading, overcoming the immunosuppressive nature of the tumor microenvironment, and enhancing specificities of the immunologic response through personalized vaccines. The review concludes by emphasizing prospective opportunities for future research and emphasizing the critical need for extensive clinical trials. These trials are essential to validate the effectivity of DC-based vaccines and solidify their role in the broader spectrum of cancer immunotherapy options.

Transcription factor-mediated reprogramming to antigen-presenting cells

Antigen-presenting cells (APCs) are a heterogenous group of immune cells composed by dendritic cells (DCs) and macrophages (Mϕ), which are critical for orchestrating immunity against cancer or infections. Several strategies have been explored to generate APC subsets, including enrichment from peripheral blood and differentiation from pluripotent or multipotent cells. During development, the generation of APC subsets is instructed by transcription factors (TFs). Direct cell reprogramming, also known as transdifferentiation, offers an approach to harness combinations of TFs to generate APCs from unrelated somatic cells, including cancer cells. In this review, we summarize the transcriptional specification of DC subsets, highlight transcriptional networks for their generation, and discuss future applications of DC reprogramming in cancer immunotherapy.

High tumor glucocorticoid receptor expression in early-stage, triple-negative breast cancer is associated with increased T-regulatory cell infiltration

PURPOSE

In early-stage, triple-negative breast cancer (TNBC), immune cell infiltration contributes to cancer cell survival, tumor invasion, and metastasis. High TNBC glucocorticoid receptor (GR) expression in early-stage TNBC is associated with poor long-term outcomes; it is unknown if high GR expression is associated with an immunosuppressed tumor microenvironment. We hypothesized that high tumor GR expression would be associated with an immune-suppressed tumor microenvironment, which could thus account for the poor prognosis observed in GR-positive TNBC.

METHODS

Formalin fixed-paraffin embedded tissue (n = 47) from patients diagnosed with early-stage TNBC from The University of Chicago (2002-2014) were evaluated for both tumor cell anti-GR immunohistochemistry and for infiltrating immune cells by immunofluorescence. Multiplexed antibodies were used to enumerate CD8+, FOXP3+, and BATF3+ immune cells infiltrating within pan-cytokeratin positive tumor cell regions of interest, and nonparametric tests compared absolute counts of each of these tumor-infiltrating immune cell types.

RESULTS

The average age of patients represented in this study was 52 years, and 63% self-identified as Black. There was no significant association between tumor GR expression and age, race, or clinical stage at diagnosis. Compared to GR-low tumors, high GR expression in early-stage, treatment-naïve TNBC was associated with relatively increased numbers of immunosuppressive FOXP3 + regulatory T cells (p = 0.046) and BATF3+immune cells (p = 0.021). While there was a positive correlation with high GR expression and CD8+ cell infiltration, it was not significant (p = 0.068). The ratio of CD8+/FOXP3+cells was also not significant (p = 0.24).

CONCLUSIONS

These data support the hypothesis that in early-stage TNBC, high GR expression is significantly associated with infiltration of immunosuppressive regulatory T cells, suggesting a tumor-intrinsic role in shaping the immunosuppressive immune cell milieu. Furthermore, suppression of GR activity may regulate the tumor immune microenvironment and improve long-term outcomes in GR-high TNBC.

PRMT5 inhibition has a potent anti-tumor activity against adenoid cystic carcinoma of salivary glands

BACKGROUND

Adenoid cystic carcinoma (ACC) is a rare glandular malignancy, commonly originating in salivary glands of the head and neck. Given its protracted growth, ACC is usually diagnosed in advanced stage. Treatment of ACC is limited to surgery and/or adjuvant radiotherapy, which often fails to prevent disease recurrence, and no FDA-approved targeted therapies are currently available. As such, identification of new therapeutic targets specific to ACC is crucial for improved patients' outcomes.

METHODS

After thoroughly evaluating the gene expression and signaling patterns characterizing ACC, we applied PandaOmics (an AI-driven software platform for novel therapeutic target discovery) on the unique transcriptomic dataset of 87 primary ACCs. Identifying protein arginine methyl transferase 5 (PRMT5) as a putative candidate with the top-scored druggability, we next determined the applicability of PRMT5 inhibitors (PRT543 and PRT811) using ACC cell lines, organoids, and patient derived xenograft (PDX) models. Molecular changes associated with response to PRMT5 inhibition and anti-proliferative effect of the combination therapy with lenvatinib was then analyzed.

RESULTS

Using a comprehensive AI-powered engine for target identification, PRMT5 was predicted among potential therapeutic target candidates for ACC. Here we show that monotherapy with selective PRMT5 inhibitors induced a potent anti-tumor activity across several cellular and animal models of ACC, which was paralleled by downregulation of genes associated with ACC tumorigenesis, including MYB and MYC (the recognized drivers of ACC progression). Furthermore, as a subset of genes targeted by lenvatinib is upregulated in ACC, we demonstrate that addition of lenvatinib enhanced the growth inhibitory effect of PRMT5 blockade in vitro, suggesting a potential clinical benefit for patients expressing lenvatinib favorable molecular profile.

CONCLUSION

Taken together, our study underscores the role of PRMT5 in ACC oncogenesis and provides a strong rationale for the clinical development of PRMT5 inhibitors as a targeted monotherapy or combination therapy for treatment of patients with this rare disease, based on the analysis of their underlying molecular profile.

Comprehensive Enteroviral Serology Links Infection and Anti-Melanoma Differentiation-Associated Protein 5 Dermatomyositis

OBJECTIVE

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous, systemic autoimmune diseases characterized by specific clinical features and, frequently, skeletal muscle inflammation. Specific subtypes of IIMs can be characterized by myositis-specific autoantibodies and are associated with distinct clinical phenotypes. Here, we focus on anti-melanoma differentiation-associated protein 5 (MDA5)-positive myositis and anti-signal recognition particle (SRP)-positive myositis, both of which exhibit seasonality but lack known environmental triggers.

METHODS

We employed Phage ImmunoPrecipitation Sequencing to profile serum antibodies against the human proteome, the human virome, and a comprehensive enterovirus library. We analyzed sera from 57 patients with anti-MDA5 autoantibodies and 57 patients with anti-SRP autoantibodies, as well as 57 healthy controls. All groups were matched for age, sex, and race.

RESULTS

Our autoantibody profiling results define specific immunogenic regions within the MDA5 and SRP autoantigens. We also discovered that in MDA5 sera, versus SRP sera, there was an elevated antibody response to the viral capsid protein 1 (VP1) of enterovirus B, which was accompanied by a decreased antibody response to rhinovirus A.

CONCLUSION

Considering the role of MDA5 as a sensor of picornaviral infections and a mediator of inflammatory signaling, our data suggest a novel etiologic link between enterovirus infection and anti-MDA5 dermatomyositis.

Protocol to study ex vivo T cell priming by conventional dendritic cells from the mouse spleen

Conventional dendritic cells (cDC) are professional antigen-presenting cells able to prime naive T cells. Here, we present a protocol for ex vivo T cell priming by murine splenic cDC. We describe the steps of injecting fluorescently labeled antigens to mice, purifying antigen-bearing cDC, and priming antigen-specific T cells ex vivo. This protocol is suitable for studying the T cell priming function of cDC in various murine models and helps factor in the effect of the microenvironment on cDC ability to uptake and process antigens. For complete details on the use and execution of this protocol, please refer to Ashayeripanah et al.1.

Type I interferon signaling in dendritic cells limits direct antigen presentation and CD8+ T cell responses against an arthritogenic alphavirus

Ross River virus (RRV) and other alphaviruses cause chronic musculoskeletal syndromes that are associated with viral persistence, which suggests deficits in immune clearance mechanisms, including CD8+ T-cell responses. Here, we used a recombinant RRV-gp33 that expresses the immunodominant CD8+ T-cell epitope of lymphocytic choriomeningitis virus (LCMV) to directly compare responses with a virus, LCMV, that strongly induces antiviral CD8+ T cells. After footpad injection, we detected fewer gp33-specific CD8+ T cells in the draining lymph node (DLN) after RRV-gp33 than LCMV infection, despite similar viral RNA levels in the foot. However, less RRV RNA was detected in the DLN compared to LCMV, with RRV localizing principally to the subcapsular region and LCMV to the paracortical T-cell zones. Single-cell RNA-sequencing analysis of adoptively transferred gp33-specific transgenic CD8+ T cells showed rapid differentiation into effector cells after LCMV but not RRV infection. This defect in RRV-specific CD8+ T effector cell maturation was corrected by local blockade of type I interferon (IFN) signaling, which also resulted in increased RRV infection in the DLN. Studies in Wdfy4-/-, CD11c-Cre B2mfl/fl, or Xcr1-Cre Ifnar1fl/fl mice that respectively lack cross-presenting capacity, MHC-I antigen presentation by dendritic cells (DCs), or type I IFN signaling in the DC1 subset show that RRV-specific CD8+ T-cell responses can be improved by enhanced direct antigen presentation by DCs. Overall, our experiments suggest that antiviral type I IFN signaling in DCs limits direct alphavirus infection and antigen presentation, which likely delays CD8+ T-cell responses.IMPORTANCEChronic arthritis and musculoskeletal disease are common outcomes of infections caused by arthritogenic alphaviruses, including Ross River virus (RRV), due to incomplete virus clearance. Unlike other viral infections that are efficiently cleared by cytotoxic CD8+ T cells, RRV infection is surprisingly unaffected by CD8+ T cells as mice lacking or having these cells show similar viral persistence in joint and lymphoid tissues. To elucidate the basis for this deficient response, we measured the RRV-specific CD8+ T-cell population size and activation state relative to another virus known to elicit a strong T-cell response. Our findings reveal that RRV induces fewer CD8+ T cells due to limited infection of immune cells in the draining lymph node. By increasing RRV susceptibility in antigen-presenting cells, we elicited a robust CD8+ T-cell response. These results highlight antigen availability and virus tropism as possible targets for intervention against RRV immune evasion and persistence.

BEACH domain proteins function as cargo-sorting adaptors in secretory and endocytic pathways

We identify BEACH domain-containing proteins (BDCPs) as novel membrane coat proteins involved in the sorting of transmembrane proteins (TMPs) on the trans-Golgi network and tubular sorting endosomes. The seven typical mammalian BDCPs share a predicted alpha-solenoid-beta propeller structure, suggesting they have a protocoatomer origin and function. We map the subcellular localization of seven BDCPs based on their dynamic colocalization with RAB and ARF small GTPases and identify five typical BDCPs on subdomains of dynamic tubular-vesicular compartments on the intersection of endocytic recycling and post-Golgi secretory pathways. We demonstrate that BDCPs interact directly with the cytosolic tails of selected TMPs and identify a subset of TMPs, whose trafficking to the plasma membrane is affected in cells lacking BDCP. We propose that the competitive binding of BDCPs and clathrin coat adaptors to the cytosolic tails of TMPs, followed by their clustering to distinct subdomains of secretory/recycling tubules function as a mechanism for sorting of TMPs in pleomorphic tubular-vesicular compartments that lack a clathrin coat.

Suppression of melanoma by mice lacking MHC-II: Mechanisms and implications for cancer immunotherapy

Immune checkpoint inhibitors interfere with T cell exhaustion but often fail to cure or control cancer long-term in patients. Using a genetic screen in C57BL/6J mice, we discovered a mutation in host H2-Aa that caused strong immune-mediated resistance to mouse melanomas. H2-Aa encodes an MHC class II α chain, and its absence in C57BL/6J mice eliminates all MHC-II expression. H2-Aa deficiency, specifically in dendritic cells (DC), led to a quantitative increase in type 2 conventional DC (cDC2) and a decrease in cDC1. H2-Aa-deficient cDC2, but not cDC1, were essential for melanoma suppression and effectively cross-primed and recruited CD8 T cells into tumors. Lack of T regulatory cells, also observed in H2-Aa deficiency, contributed to melanoma suppression. Acute disruption of H2-Aa was therapeutic in melanoma-bearing mice, particularly when combined with checkpoint inhibition, which had no therapeutic effect by itself. Our findings suggest that inhibiting MHC-II may be an effective immunotherapeutic approach to enhance immune responses to cancer.

The clinical relevance of WDFY4 in autoimmune diseases in diverse ancestral populations

WD repeat- and FYVE domain-containing protein 4 (WDFY4), coded by a gene on 10q11.23, is a member of the BEACH (Beige and Chediak-Higashi) domain-containing family. Genome-wide association studies identified WDFY4 variants as a risk factor for SLE in Asian and European populations. WDFY4 variants are also associated with RA and primary biliary cholangitis, in different ancestry populations. The WDFY4 protein plays an essential role in the cross-presentation of classic dendritic cells, reactive oxygen species-induced apoptosis of CD8+ T cells, and non-canonical autophagic activity in B cells. A novel variant rs7919656 was identified in Japanese clinically amyopathic dermatomyositis patients, with a highly expressed truncated isoform augmenting the melanoma differentiation-associated gene 5 (MDA5) signalling pathway. The same variant was later found to be significantly associated with RP-ILD in Chinese MDA5+DM patients. Here, we briefly review the association of WDFY4 with autoimmune diseases and its known function in the immune response.

Lack of WDFY4 leads to impaired immune response and poor cancer prognosis

WDFY4 plays an essential role in the immune system by regulating B-cell growth and development and participating in antigen processing during cross-presentation. WDFY4 is closely related to asthma and systemic lupus erythematosus; however, its role in cancer remains unclear. The purpose of this study is to use bioinformatics to determine whether abnormal expression of WDFY4 is a risk factor for cancer and to preliminarily analyze the ways in which WDFY4 affects cancer through experiments. R language packages and bioinformatic database were used to mine the potential carcinogenic effect of WDFY4 and analyze the differential WDFY4 expression in cancer, gene mutations, different tumor prognoses, immune cell infiltration, tumor microenvironment, and DNA methylation correlation. H1975 and A549 cell lines were infected with lentiviruses to overexpress WDFY4, and the effect of WDFY4 on the activity, proliferation, apoptosis, and cell cycle of lung cancer cells was analyzed. WDFY4 was differentially expressed in human tumors in unpaired and paired samples. The differential expression of WDFY4 in unpaired and paired or protein samples from the Clinical Proteome Tumor Analysis Consortium of eight cancers was consistent. WDFY4 methylation was downregulated in 17 cancer types and caused prognostic differences in different directions in some cancers. WDFY4 overexpression significantly inhibited the activity and proliferation of lung cancer cell lines, promoted apoptosis, and caused cell cycle arrest. Differential WDFY4 expression in cancers leads to differences in the prognosis of various cancers. WDFY4 can be an independent prognostic factor for glioma, KIRC, and LUSC.

Multifaceted Aspects of Dysfunctional Myelopoiesis in Cancer and Therapeutic Perspectives with Focus on HCC

Myelopoiesis provides for the formation and continued renewal of cells belonging primarily to the innate immune system. It is a highly plastic process that secures the response to external and internal stimuli to face acute and changing needs. Infections and chronic diseases including cancer can modulate it by producing several factors, impacting proliferation and differentiation programs. While the lymphocytic compartment has attracted major attention due to the role of adaptive immunity in anticancer immune response, in recent years, research has found convincing evidence that confirms the importance of innate immunity and the key function played by emergency myelopoiesis. Due to cancer's ability to manipulate myelopoiesis to its own advantage, the purpose of this review is to outline myelopoiesis processes within the tumor microenvironment and suggest possible therapeutic lines of research to restore the physiological functioning of the host's immune system, with a special outlook on hepatocellular carcinoma (HCC).

The hallmarks of cancer immune evasion

According to the widely accepted "three Es" model, the host immune system eliminates malignant cell precursors and contains microscopic neoplasms in a dynamic equilibrium, preventing cancer outgrowth until neoplastic cells acquire genetic or epigenetic alterations that enable immune escape. This immunoevasive phenotype originates from various mechanisms that can be classified under a novel "three Cs" conceptual framework: (1) camouflage, which hides cancer cells from immune recognition, (2) coercion, which directly or indirectly interferes with immune effector cells, and (3) cytoprotection, which shields malignant cells from immune cytotoxicity. Blocking the ability of neoplastic cells to evade the host immune system is crucial for increasing the efficacy of modern immunotherapy and conventional therapeutic strategies that ultimately activate anticancer immunosurveillance. Here, we review key hallmarks of cancer immune evasion under the "three Cs" framework and discuss promising strategies targeting such immunoevasive mechanisms.

Regulation of neutrophil associated RNASET2 expression in rheumatoid arthritis

Neutrophils (PMNs) are key players of innate immune responses through the release of cytoplasmic granule content and the formation of neutrophil extracellular traps (NETs). RNASET2 is an acidic ribonuclease, recently proposed as an alarmin signal associated with inflammatory responses. Here we show that, along the neutrophil maturation cascade, RNASET2 is expressed in segmented and mature PMNs. In human PMNs, RNASET2 colocalized with primary and tertiary granules and was found to be associated with NETs following PMA or Nigericin stimulation. Similarly, activation of PMNs by soluble immune complexes, a hallmark of several autoimmune diseases, also induced RNASET2-associated NETs. Genome-wide association studies recently identified RNASET2 among a cluster of genes associated with increased susceptibility to develop autoimmune diseases, including rheumatoid arthritis (RA). RNASET2 was found expressed by PMNs and macrophages infiltrating inflamed joints in a murine model of RA (K/BxN Serum-Transfer-Induced Arthritis, STIA), by immunostaining. Similar results were found in synovial biopsies of RA patients with active disease. In addition, we demonstrate that RNASET2 circulating levels correlated with the onset and the severity of disease in two mouse models of inflammatory arthritis, STIA and CIA (Collagen-Induced Arthritis) and in serum of RA patients. These results show that PMNs are an important source of RNASET2 and that its circulating levels are associated with RA development suggesting a role for RNASET2 in the pathogenesis of immune-mediated diseases.

Formulating a TMEM176B blocker in chitosan nanoparticles uncouples its paradoxical roles in innate and adaptive antitumoral immunity

The immunoregulatory cation channel TMEM176B plays a dual role in tumor immunity. On the one hand, TMEM176B promotes antigen cross-presentation to CD8+ T cells by regulating phagosomal pH in dendritic cells (DCs). On the other hand, it inhibits NLRP3 inflammasome activation through ionic mechanisms in DCs, monocytes and macrophages. We speculated that formulating BayK8644 in PEGylated chitosan nanoparticles (NP-PEG-BayK8644) should slowly release the compound and by that mean avoid cross-presentation inhibition (which happens with a fast 30 min kinetics) while still triggering inflammasome activation. Chitosan nanocarriers were successfully obtained, exhibiting a particle size within the range of 200 nm; they had a high positive surface charge and a 99 % encapsulation efficiency. In in vitro studies, NP-PEG-BayK8644 did not inhibit antigen cross-presentation by DCs, unlike the free compound. The NP-PEG-BayK8644 activated the inflammasome in a Tmem176b-dependent manner in DCs. We administered either empty (eNP-PEG) or NP-PEG-BayK8644 to mice with established tumors. NP-PEG-BayK8644 significantly controlled tumor growth and improved mice survival compared to both eNP-PEG and free BayK8644 in melanoma and lymphoma models. This effect was associated with enhanced inflammasome activation by DCs in the tumor-draining lymph node and infiltration of the tumor by CD8+ T cells. Thus, encapsulation of BayK8644 in chitosan NPs improves the anti-tumoral properties of the compound by avoiding inhibition of antigen cross-presentation.

The pore-forming apolipoprotein APOL7C drives phagosomal rupture and antigen cross-presentation by dendritic cells

Conventional dendritic cells (cDCs) generate protective cytotoxic T lymphocyte (CTL) responses against extracellular pathogens and tumors. This is achieved through a process known as cross-presentation (XP), and, despite its biological importance, the mechanism(s) driving XP remains unclear. Here, we show that a cDC-specific pore-forming protein called apolipoprotein L 7C (APOL7C) is up-regulated in response to innate immune stimuli and is recruited to phagosomes. Association of APOL7C with phagosomes led to phagosomal rupture and escape of engulfed antigens to the cytosol, where they could be processed via the endogenous MHC class I antigen processing pathway. Accordingly, mice deficient in APOL7C did not efficiently prime CD8+ T cells in response to immunization with bead-bound and cell-associated antigens. Together, our data indicate the presence of dedicated apolipoproteins that mediate the delivery of phagocytosed proteins to the cytosol of activated cDCs to facilitate XP.

Optimization of the Irf8 +32-kb enhancer disrupts dendritic cell lineage segregation

Autoactivation of lineage-determining transcription factors mediates bistable expression, generating distinct cell phenotypes essential for complex body plans. Classical type 1 dendritic cell (cDC1) and type 2 dendritic cell (cDC2) subsets provide nonredundant functions for defense against distinct immune challenges. Interferon regulatory factor 8 (IRF8), the cDC1 lineage-determining transcription factor, undergoes autoactivation in cDC1 progenitors to establish cDC1 identity, yet its expression is downregulated during cDC2 differentiation by an unknown mechanism. This study reveals that the Irf8 +32-kb enhancer, responsible for IRF8 autoactivation, is naturally suboptimized with low-affinity IRF8 binding sites. Introducing multiple high-affinity IRF8 sites into the Irf8 +32-kb enhancer causes a gain-of-function effect, leading to erroneous IRF8 autoactivation in specified cDC2 progenitors, redirecting them toward cDC1 and a novel hybrid DC subset with mixed-lineage phenotypes. Further, this also causes a loss-of-function effect, reducing Irf8 expression in cDC1s. These developmental alterations critically impair both cDC1-dependent and cDC2-dependent arms of immunity. Collectively, our findings underscore the significance of enhancer suboptimization in the developmental segregation of cDCs required for normal immune function.

Specific Requirement of the p84/p110γ Complex of PI3Kγ for Antibody-Activated, Inducible Cross-Presentation in Murine Type 2 DCs

Cross-presentation by MHCI is optimally efficient in type 1 dendritic cells (DC) due to their high capacity for antigen processing. However, through specific pathways, other DCs, such as type 2 DCs and inflammatory DCs (iDCs) can also cross-present antigens. FcγR-mediated uptake by type 2 DC and iDC subsets mediates antibody-dependent cross-presentation and activation of CD8+ T cell responses. Here, an important role for the p84 regulatory subunit of PI3Kγ in mediating efficient cross-presentation of exogenous antigens in otherwise inefficient cross-presenting cells, such as type 2 DCs and GM-CSF-derived iDCs is identified. FcγR-mediated cross-presentation is shown in type 2 and iDCs depend on the enzymatic activity of the p84/p110γ complex of PI3Kγ, which controls the activity of the NADPH oxidase NOX2 and ROS production in murine spleen type 2 DCs and GM-CSF-derived iDCs. In contrast, p84/p110γ is largely dispensable for cross-presentation by type 1 DCs. These findings suggest that PI3Kγ-targeted therapies, currently considered for oncological practice, may interfere with the ability of type 2 DCs and iDCs to cross-present antigens contained in immune complexes.

Immunotherapy response induces divergent tertiary lymphoid structure morphologies in hepatocellular carcinoma

Tertiary lymphoid structures (TLS) are associated with improved response in solid tumors treated with immune checkpoint blockade, but understanding of the prognostic and predictive value of TLS and the circumstances of their resolution is incomplete. Here we show that in hepatocellular carcinoma treated with neoadjuvant immunotherapy, high intratumoral TLS density at the time of surgery is associated with pathologic response and improved relapse-free survival. In areas of tumor regression, we identify a noncanonical involuted morphology of TLS marked by dispersion of the B cell follicle, persistence of a T cell zone enriched for T cell-mature dendritic cell interactions and increased expression of T cell memory markers. Collectively, these data suggest that TLS can serve as both a prognostic and predictive marker of response to immunotherapy in hepatocellular carcinoma and that late-stage TLS may support T cell memory formation after elimination of a viable tumor.

In vivo dendritic cell reprogramming for cancer immunotherapy

Immunotherapy can lead to long-term survival for some cancer patients, yet generalized success has been hampered by insufficient antigen presentation and exclusion of immunogenic cells from the tumor microenvironment. Here, we developed an approach to reprogram tumor cells in vivo by adenoviral delivery of the transcription factors PU.1, IRF8, and BATF3, which enabled them to present antigens as type 1 conventional dendritic cells. Reprogrammed tumor cells remodeled their tumor microenvironment, recruited, and expanded polyclonal cytotoxic T cells; induced tumor regressions; and established long-term systemic immunity in multiple mouse melanoma models. In human tumor spheroids and xenografts, reprogramming to immunogenic dendritic-like cells progressed independently of immunosuppression, which usually limits immunotherapy. Our study paves the way for human clinical trials of in vivo immune cell reprogramming for cancer immunotherapy.

Analysis of the heterogeneity and complexity of murine extraorbital lacrimal gland via single-cell RNA sequencing

PURPOSE

The lacrimal gland is essential for maintaining ocular surface health and avoiding external damage by secreting an aqueous layer of the tear film. However, a healthy lacrimal gland's inventory of cell types and heterogeneity remains understudied.

METHODS

Here, 10X Genome-based single-cell RNA sequencing was used to generate an unbiased classification of cellular diversity in the extraorbital lacrimal gland (ELG) of C57BL/6J mice. From 43,850 high-quality cells, we produced an atlas of cell heterogeneity and defined cell types using classic marker genes. The possible functions of these cells were analyzed through bioinformatics analysis. Additionally, the CellChat was employed for a preliminary analysis of the cell-cell communication network in the ELG.

RESULTS

Over 37 subclasses of cells were identified, including seven types of glandular epithelial cells, three types of fibroblasts, ten types of myeloid-derived immune cells, at least eleven types of lymphoid-derived immune cells, and five types of vascular-associated cell subsets. The cell-cell communication network analysis revealed that fibroblasts and immune cells play a pivotal role in the dense intercellular communication network within the mouse ELG.

CONCLUSIONS

This study provides a comprehensive transcriptome atlas and related database of the mouse ELG.

Memory T-Cells Contribute to Calcium Release from Bones during Lactation in Mice

Objective: Milk production during lactation places a high demand for calcium that is fulfilled both from maternal bone resorption and diet. While it is known that mammary gland-derived PTHrP drives bone resorption during lactation, the impact of postpartum estrogen loss on bone has been unclear. Methods: We used a case-control study design to test the effect of estrogen loss in lactating mice. Results: In the present study, we show for the first time that estrogen loss during lactation activates memory T-cells (TM) to produce TNFα and IL-17A to aid in bone resorption and calcium release. Our studies reveal a new mechanism for the release of calcium from bone postpartum. The findings provide several new insights. First, the immune system plays a critical role in milk production postpartum. Second, evolutionarily, the pathway serves the physiological purpose of increasing bone resorption to release calcium for breastmilk production postpartum but becomes maladaptive postmenopause, leading to osteoporosis. Finally, these results highlight the crosstalk between the brain-bone-breast-endocrine axis and the immune system during lactation.

Immunometabolic characteristics of Dendritic Cells and its significant modulation by mitochondria-associated signaling in the tumor microenvironment influence cancer progression

Dendritic cells (DCs) mediated T-cell responses is critical to anti-tumor immunity. This study explores immunometabolic attributes of DC, emphasizing on mitochondrial association, in Tumor Microenvironment (TME) that regulate cancer progression. Conventional DC subtypes cross-present tumor-associated antigens to activate lymphocytes. However, plasmacytoid DCs participate in both pro- and anti-tumor signaling where mitochondrial reactive oxygen species (mtROS) play crucial role. CTLA-4, CD-47 and other surface-receptors of DC negatively regulates T-cell. Increased glycolysis-mediated mitochondrial citrate buildup and translocation to cytosol with augmented NADPH, enhances mitochondrial fatty acid synthesis fueling DCs. Different DC subtypes and stages, exhibit variable mitochondrial content, membrane potential, structural dynamics and bioenergetic metabolism regulated by various cytokine stimulation, e.g., GM-CSF, IL-4, etc. CD8α+ cDC1s augmented oxidative phosphorylation (OXPHOS) which diminishes at advance effector stages. Glutaminolysis in mitochondria supplement energy in DCs but production of kynurenine and other oncometabolites leads to immunosuppression. Mitochondria-associated DAMPs cause activation of cGAS-STING pathway and inflammasome oligomerization stimulating DC and T cells. In this study, through a comprehensive survey and critical analysis of the latest literature, the potential of DC metabolism for more effective tumor therapy is highlighted. This underscores the need for future research to explore specific therapeutic targets and potential drug candidates.

Dendritic cell-based immunotherapy in non-small cell lung cancer: a comprehensive critical review

Despite treatment advances through immunotherapies, including anti-PD-1/PD-L1 therapies, the overall prognosis of non-small cell lung cancer (NSCLC) patients remains poor, underscoring the need for novel approaches that offer long-term clinical benefit. This review examined the literature on the subject over the past 20 years to provide an update on the evolving landscape of dendritic cell-based immunotherapy to treat NSCLC, highlighting the crucial role of dendritic cells (DCs) in immune response initiation and regulation. These cells encompass heterogeneous subsets like cDC1s, cDC2s, and pDCs, capable of shaping antigen presentation and influencing T cell activation through the balance between the Th1, Th2, and Th17 profiles and the activation of regulatory T lymphocytes (Treg). The intricate interaction between DC subsets and the high density of intratumoral mature DCs shapes tumor-specific immune responses and impacts therapeutic outcomes. DC-based immunotherapy shows promise in overcoming immune resistance in NSCLC treatment. This article review provides an update on key clinical trial results, forming the basis for future studies to characterize the role of different types of DCs in situ and in combination with different therapies, including DC vaccines.

Macrophage WDFY3, a protector against autoimmunity

Efficient efferocytosis is essential for maintaining homeostasis. Excessive apoptotic cell (AC) death and impaired macrophage efferocytosis lead to autoantigen release and autoantibody production, immune activation, and organ damage. It remains unclear whether these immunogenic autoantigens are the sole cause of increased autoimmunity or if efferocytosis of ACs directly influences macrophage function, impacting their ability to activate T cells and potentially amplifying autoimmune responses. Additionally, it has not been established if enhancing macrophage efferocytosis or modulating macrophage responses to AC engulfment can be protective in autoimmune-like disorders. Our previous work showed WDFY3 is crucial for efficient macrophage efferocytosis. This study reveals that myeloid knockout of Wdfy3 exacerbates autoimmunity in young mice with increased AC burden by systemic injections of ACs and in middle-aged mice developing spontaneous autoimmunity, whereas ectopic overexpression of WDFY3 suppresses autoimmunity in these models. Macrophages, as efferocytes, can activate T cells and the inflammasome upon engulfing ACs, which are suppressed by overexpressing WDFY3. This work uncovered the role of WDFY3 as a protector against autoimmunity by promoting macrophage efferocytosis thus limiting autoantigen production, as well as mitigating T cell activation and inflammasome activation.

CRISPR/Cas9 screening: unraveling cancer immunotherapy's 'Rosetta Stone'

Clustered regularly interspaced palindromic repeats (CRISPR)-based technology, a powerful toolset for the unbiased functional genomic screening of biological processes, has facilitated several scientific breakthroughs in the biomedical field. Cancer immunotherapy has advanced the treatment of numerous malignancies that previously had restricted treatment options or unfavorable outcomes. In the realm of cancer immunotherapy, the application of CRISPR/CRISPR-associated protein 9 (Cas9)-based genetic perturbation screening has enabled the identification of genes, biomarkers, and signaling pathways that govern various cancer immunoreactivities, as well as the development of effective immunotherapeutic targets. In this review, we summarize the advances in CRISPR/Cas9-based screening for cancer immunotherapy and outline the immunotherapeutic targets identified via CRISPR screening based on cancer-type classification.

Intestinal cDC1s provide cues required for CD4+ T cell-mediated resistance to Cryptosporidium

Cryptosporidium is an enteric pathogen and a prominent cause of diarrheal disease worldwide. Control of Cryptosporidium requires CD4+ T cells, but how protective CD4+ T cell responses are generated is poorly understood. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to understand the basis for CD4+ T cell priming and effector function. These studies revealed that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node but differentiate into Th1 cells in the gut to provide local parasite control. Although type 1 conventional dendritic cells (cDC1s) were dispensable for CD4+ T cell priming, they were required for CD4+ T cell gut homing and were a source of IL-12 at the site of infection that promoted local production of IFN-γ. Thus, cDC1s have distinct roles in shaping CD4+ T cell responses to an enteric infection: first, to promote gut homing from the mesLN, and second, to drive effector responses in the intestine.

Constitutive Flt3 signaling impacts conventional dendritic cell function

The development of dendritic cells (DCs) depends on signaling via the FMS-like tyrosine kinase 3 (Flt3) receptor. How Flt3 signaling impacts terminally differentiated DC function is unknown. This is important given the increasing interest in exploiting Flt3 for vaccination and tumor immunotherapy. Here, we examined DCs in mice harboring constitutively activated Flt3 (Flt3-ITD). Flt3ITD/ITD mice possessed expanded splenic DC subsets including plasmacytoid DC, conventional DC (cDC)1, cDC2, double positive (DP) cDC1 (CD11c+ CD8+ CD11b- CD103+ CD86+), noncanonical (NC) cDC1 (CD11c+ CD8+ CD11b- CD103- CD86-) and single positive (SP) cDC1 (CD11c+ CD8+ CD11b- CD103- CD86+). Outcomes of constitutive Flt3 signaling differed depending on the cDC subset examined. In comparison with wild type (WT) DCs, all Flt3ITD/ITD cDCs displayed an altered surface phenotype with changes in costimulatory molecules, major histocompatibility complex class I (MHC I) and II (MHC II). Cytokine secretion patterns, antigen uptake, antigen proteolysis and antigen presenting function differed between WT and Flt3ITD/ITD subsets, particularly cDC2. In summary, Flt3 signaling impacts the function of terminally differentiated cDCs with important consequences for antigen presentation.

Flow cytometry-assisted analysis of phenotypic maturation markers on an immortalized dendritic cell line

Dendritic cells (DCs), and especially so conventional type I DCs (cDC1s), are fundamental regulators of anticancer immunity, largely reflecting their superior ability to engulf tumor-derived material and process it for cross-presentation on MHC Class I molecules to CD8+ cytotoxic T lymphocytes (CTLs). Thus, investigating key DC functions including (but not limited to) phagocytic capacity, expression of CTL-activating ligands on the cell surface, and cross-presentation efficacy is an important component of multiple immuno-oncology studies. Unfortunately, DCs are terminally differentiated cells, implying that they cannot be propagated indefinitely in vitro and hence must be generated ad hoc from circulating or bone marrow-derived precursors, which presents several limitations. Here, we propose a simple, cytofluorometric method to quantify phenotypic activation markers including CD80, CD86 and MHC class II molecules on the surface of a conditionally immortalized immature DC line that can be indefinitely propagated in vitro but also driven into maturation at will with a simple change in culture conditions. Upon appropriate scaling and automatization, this approach is compatible with high-throughput screening programs for the discovery of novel DC activators that do not suffer from batch variability and other limitations associated with the generation of fresh DCs.

Dendritic cell subsets and implications for cancer immunotherapy

Dendritic cells (DCs) play a central role in the orchestration of effective T cell responses against tumors. However, their functional behavior is context-dependent. DC type, transcriptional program, location, intratumoral factors, and inflammatory milieu all impact DCs with regard to promoting or inhibiting tumor immunity. The following review introduces important facets of DC function, and how subset and phenotype can affect the interplay of DCs with other factors in the tumor microenvironment. It will also discuss how current cancer treatment relies on DC function, and survey the myriad ways with which immune therapy can more directly harness DCs to enact antitumor cytotoxicity.

Targeting immunogenic cell stress and death for cancer therapy

Immunogenic cell death (ICD), which results from insufficient cellular adaptation to specific stressors, occupies a central position in the development of novel anticancer treatments. Several therapeutic strategies to elicit ICD - either as standalone approaches or as means to convert immunologically cold tumours that are insensitive to immunotherapy into hot and immunotherapy-sensitive lesions - are being actively pursued. However, the development of ICD-inducing treatments is hindered by various obstacles. Some of these relate to the intrinsic complexity of cancer cell biology, whereas others arise from the use of conventional therapeutic strategies that were developed according to immune-agnostic principles. Moreover, current discovery platforms for the development of novel ICD inducers suffer from limitations that must be addressed to improve bench-to-bedside translational efforts. An improved appreciation of the conceptual difference between key factors that discriminate distinct forms of cell death will assist the design of clinically viable ICD inducers.

Tim4 enables large peritoneal macrophages to cross-present tumor antigens at early stages of tumorigenesis

Receptors controlling the cross-presentation of tumor antigens by macrophage subsets in cancer tissues are poorly explored. Here, we show that TIM4+ large peritoneal macrophages efficiently capture and cross-present tumor-associated antigens at early stages of peritoneal infiltration by ovarian cancer cells. The phosphatidylserine (PS) receptor TIM4 promotes maximal uptake of dead cells or PS-coated artificial targets and triggers inflammatory and metabolic gene programs in combination with cytoskeletal remodeling and upregulation of transcriptional signatures related to antigen processing. At the cellular level, TIM4-mediated engulfment induces nucleation of F-actin around nascent phagosomes, delaying the recruitment of vacuolar ATPase, acidification, and cargo degradation. In vivo, TIM4 deletion blunts induction of early anti-tumoral effector CD8 T cells and accelerates the progression of ovarian tumors. We conclude that TIM4-mediated uptake drives the formation of specialized phagosomes that prolong the integrity of ingested antigens and facilitate cross-presentation, contributing to immune surveillance of the peritoneum.

Comparative analysis of the nucleus accumbens transcriptional features in multiple depressive animal models

Chronic stress is deemed a significant clinical contributor to depression. The use of animal models of chronic stress can fully reveal the complex pathological mechanisms and their changing trends in the pathogenesis of depression, which is crucial for both disease prevention and therapy. It is also unknown how various forms of stress differ in their impact on animal physiology and behavior. The nucleus accumbens (NAc), an essential brain area for the pathophysiology of depression, and its underlying neural mechanisms remain unclear. Here, we systematically compared transcriptional signatures in the NAc of four chronic stress models in rats: chronic unpredictable mild stress (CUMS), chronic social defeat stress (CSDS), learned helplessness (LH), chronic restraint stress (CRS). The majority of differentially expressed genes (DEGs) were unique to a single depression model, while the rank-rank hypergeometric overlap analysis showed that the CSDS and CRS models had the greatest overlap, and the CRS and CUMS models had the least. Then, we performed pathway analysis of the differential genes and found that the neuroactive ligand-receptor interaction pathway was significantly enriched not only in the LH, CRS and CSDS stress models, but also significantly enriched in stress genes that were also altered in at least two stress models. Finally, we found three hub genes (Dcx, Tnc and Wdfy4) by constructing co-expression networks for stress genes. In summary, our research has the potential to offer fresh insights into the molecular mechanisms underlying depression induced by different types of stress, highlighting both their similarities and differences. It may provide valuable clues for understanding the pathogenesis of depression.

Control of adaptive immunity by pattern recognition receptors

One of the most significant conceptual advances in immunology in recent history is the recognition that signals from the innate immune system are required for induction of adaptive immune responses. Two breakthroughs were critical in establishing this paradigm: the identification of dendritic cells (DCs) as the cellular link between innate and adaptive immunity and the discovery of pattern recognition receptors (PRRs) as a molecular link that controls innate immune activation as well as DC function. Here, we recount the key events leading to these discoveries and discuss our current understanding of how PRRs shape adaptive immune responses, both indirectly through control of DC function and directly through control of lymphocyte function. In this context, we provide a conceptual framework for how variation in the signals generated by PRR activation, in DCs or other cell types, can influence T cell differentiation and shape the ensuing adaptive immune response.

Functional CRISPR screens in T cells reveal new opportunities for cancer immunotherapies

T cells are fundamental components in tumour immunity and cancer immunotherapies, which have made immense strides and revolutionized cancer treatment paradigm. However, recent studies delineate the predicament of T cell dysregulation in tumour microenvironment and the compromised efficacy of cancer immunotherapies. CRISPR screens enable unbiased interrogation of gene function in T cells and have revealed functional determinators, genetic regulatory networks, and intercellular interactions in T cell life cycle, thereby providing opportunities to revamp cancer immunotherapies. In this review, we briefly described the central roles of T cells in successful cancer immunotherapies, comprehensively summarised the studies of CRISPR screens in T cells, elaborated resultant master genes that control T cell activation, proliferation, fate determination, effector function, and exhaustion, and highlighted genes (BATF, PRDM1, and TOX) and signalling cascades (JAK-STAT and NF-κB pathways) that extensively engage in multiple branches of T cell responses. In conclusion, this review bridged the gap between discovering element genes to a specific process of T cell activities and apprehending these genes in the global T cell life cycle, deepened the understanding of T cell biology in tumour immunity, and outlined CRISPR screens resources that might facilitate the development and implementation of cancer immunotherapies in the clinic.

Dendritic cells as orchestrators of anticancer immunity and immunotherapy

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting innate immune cells that regulate adaptive immunity, including against cancer. Therefore, understanding the precise activities of DCs in tumours and patients with cancer is important. The classification of DC subsets has historically been based on ontogeny; however, single-cell analyses are now additionally revealing a diversity of functional states of DCs in cancer. DCs can promote the activation of potent antitumour T cells and immune responses via numerous mechanisms, although they can also be hijacked by tumour-mediated factors to contribute to immune tolerance and cancer progression. Consequently, DC activities are often key determinants of the efficacy of immunotherapies, including immune-checkpoint inhibitors. Potentiating the antitumour functions of DCs or using them as tools to orchestrate short-term and long-term anticancer immunity has immense but as-yet underexploited therapeutic potential. In this Review, we outline the nature and emerging complexity of DC states as well as their functions in regulating adaptive immunity across different cancer types. We also describe how DCs are required for the success of current immunotherapies and explore the inherent potential of targeting DCs for cancer therapy. We focus on novel insights on DCs derived from patients with different cancers, single-cell studies of DCs and their relevance to therapeutic strategies.

Condensin-mediated restriction of retrotransposable elements facilitates brain development in Drosophila melanogaster

Neural stem and progenitor cell (NSPC) maintenance is essential for ensuring that organisms are born with proper brain volumes and head sizes. Microcephaly is a disorder in which babies are born with significantly smaller head sizes and cortical volumes. Mutations in subunits of the DNA organizing complex condensin have been identified in microcephaly patients. However, the molecular mechanisms by which condensin insufficiency causes microcephaly remain elusive. We previously identified conserved roles for condensins in repression of retrotransposable elements (RTEs). Here, we show that condensin subunit knockdown in NSPCs of the Drosophila larval central brain increases RTE expression and mobility which causes cell death, and significantly decreases adult head sizes and brain volumes. These findings suggest that unrestricted RTE expression and activity may lead to improper brain development in condensin insufficient organisms, and lay the foundation for future exploration of causative roles for RTEs in other microcephaly models.

Dendritic cell-targeted therapy expands CD8 T cell responses to bona-fide neoantigens in lung tumors

Cross-presentation by type 1 DCs (cDC1) is critical to induce and sustain antitumoral CD8 T cell responses to model antigens, in various tumor settings. However, the impact of cross-presenting cDC1 and the potential of DC-based therapies in tumors carrying varied levels of bona-fide neoantigens (neoAgs) remain unclear. Here we develop a hypermutated model of non-small cell lung cancer in female mice, encoding genuine MHC-I neoepitopes to study neoAgs-specific CD8 T cell responses in spontaneous settings and upon Flt3L + αCD40 (DC-therapy). We find that cDC1 are required to generate broad CD8 responses against a range of diverse neoAgs. DC-therapy promotes immunogenicity of weaker neoAgs and strongly inhibits the growth of high tumor-mutational burden (TMB) tumors. In contrast, low TMB tumors respond poorly to DC-therapy, generating mild CD8 T cell responses that are not sufficient to block progression. scRNA transcriptional analysis, immune profiling and functional assays unveil the changes induced by DC-therapy in lung tissues, which comprise accumulation of cDC1 with increased immunostimulatory properties and less exhausted effector CD8 T cells. We conclude that boosting cDC1 activity is critical to broaden the diversity of anti-tumoral CD8 T cell responses and to leverage neoAgs content for therapeutic advantage.

Gel-mediated recruitment of conventional type 1 dendritic cells potentiates the therapeutic effects of radiotherapy

The efficacy of radiotherapy has not yet achieved optimal results, partially due to insufficient priming and infiltration of effector immune cells within the tumor microenvironment (TME), which often exhibits suppressive phenotypes. In particular, the infiltration of X-C motif chemokine receptor 1 (XCR1)-expressing conventional type-1 dendritic cells (cDC1s), which are critical in priming CD8+ cytotoxic T cells, within the TME is noticeably restricted. Hence, we present a facile methodology for the efficient fabrication of a calcium phosphate hydrogel loaded with X-C motif chemokine ligand 1 (XCL1) to selectively recruit cDC1s. Manganese phosphate microparticles were also loaded into this hydrogel to reprogram the TME via cGAS-STING activation, thereby facilitating the priming of cDC1s propelled specific CD8+ T cells. They also polarize tumor-associated macrophages towards the M1 phenotype and reduce the proportion of regulatory cells, effectively reversing the immunosuppressive TME into an immune-active one. The yielded XCL1@CaMnP gel exhibits significant efficacy in enhancing the therapeutic outcomes of radiotherapy, particularly when concurrently administered with postoperative radiotherapy, resulting in an impressive 60 % complete response rate. Such XCL1@CaMnP gel, which recruits cDC1s to present tumor antigens generated in situ, holds great potential as a versatile platform for enhanced cancer treatment through modulating the immunosuppressive TME.