Differentiation Of Dendritic Cells Research Articles

A phase Ib/II study (IMMCO-1) of atezolizumab plus tivozanib in immunologically cold pancreatic, gallbladder, and biliary cancers.

TPS491 Background: Checkpoint inhibition (CPI) represents a significant advance in cancer care however it is not effective in the treatment of several immunologically cold tumors including pancreatic, gallbladder, and biliary cancers where checkpoint inhibitors have produced objective response rates of <5%. VEGF is thought to play a key role in modulating the anti-tumor immune response. Secreted by tumors, it leads to endothelial cell proliferation, vascular permeability, and vasodilation that together leads to the development of an abnormal vasculature with excessive permeability and poor blood flow, thus limiting immune surveillance. In addition, VEGF inhibits dendritic cell differentiation, limiting the presentation of tumor antigens to CD4 and CD8 T cells. Through the inhibition of VEGF, it may be possible to potentiate the effect of immune checkpoint blockade. Combined use of a VEGF tyrosine kinase inhibitor (TKI) and checkpoint inhibitor is already standard of care in advanced kidney, cervical and endometrial cancers. There has been suggestion that such a combination may have clinical activity in some microsatellite stable (MSS) GI malignancies. This signal seeking study aims to build upon those observations by incorporating a pan-VEGF axis inhibitor (tivozanib) with CPI. Methods: This is an open-label non-randomized phase Ib/II signal seeking basket study in multiple immunologically cold tumors. The co-primary endpoints are safety and efficacy of the combination of the VEGF-TKI tivozanib and CPI atezolizumab. Key eligibility criteria includes patients with MSS pancreatic, biliary (cholangiocarcinoma and gallbladder), well-differentiated grade 2 and 3 neuroendocrine tumors, ovarian and vulvar cancer, soft tissue sarcoma, castrate resistant prostate cancer, and HER2 positive hormone receptor negative breast cancer, that is metastatic and progressed on at least one line of therapy. Key exclusion criteria will include patients with known mismatch repair deficiency, microsatellite instability, or high tumor mutational burden. The phase Ib portion will assess the safety profile of the combination of tivozanib and atezolizumab with a potential dose de-escalation of tivozanib using a 3+3 study design. Starting doses include tivozanib 1.34 mg per day for 21 days of each 28-day cycle and atezolizumab 1680 mg on day 1 of every 28-day cycle. The phase II portion will enroll up to 26 additional patients using the dose of tivozanib found to be safe in the Ib portion. Disease response assessments are every 12 weeks with CT Chest, Abdomen, and Pelvis via RECIST 1.1. Treatment will continue until progression or intolerance. This signal seeking study is looking to confirm the best objective response rate for evaluable patients increasing from <7% (null hypothesis) to 25% (one-sided alpha = 0.05; 80% power). Active enrollment continues. Clinical trial information: NCT05000294.

Reduced Plasmacytoid Dendritic Cell Output Is Associated With High Risk in Low-grade Myelodysplastic Syndrome.

Reduced Plasmacytoid Dendritic Cell Output Is Associated With High Risk in Low-grade Myelodysplastic Syndrome.

TNFR2 Depletion Reduces Psoriatic Inflammation in Mice by Downregulating Specific Dendritic Cell Populations in Lymph Nodes and Inhibiting IL-23/IL-17 Pathways

TNF-α, a proinflammatory cytokine, is a crucial mediator of psoriasis pathogenesis. TNF-α functions by activating TNFR1 and TNFR2. Anti-TNF drugs that neutralize TNF-α, thus blocking the activation of TNFR1 and TNFR2, have been proven highly therapeutic in psoriatic diseases. TNF-α also plays an important role in host defense; thus, anti-TNF therapy can cause potentially serious adverse effects, including opportunistic infections and latent tuberculosis reactivation. These adverse effects are attributed to TNFR1 inactivation. Therefore, understanding the relative contributions of TNFR1 and TNFR2 has clinical implications in mitigating psoriasis versus global TNF-α blockade. We found a significant reduction in psoriasis lesions as measured by epidermal hyperplasia, characteristic gross skin lesion, and IL-23 or IL-17A levels in Tnfr2-knockout but not in Tnfr1-knockout mice in the imiquimod psoriasis model. Furthermore, imiquimod-mediated increase in the myeloid dendritic cells, TNF/inducible nitric oxide synthase‒producing dendritic cells, and IL-23 expression in the draining lymph nodes were dependent on TNFR2 but not on TNFR1. Together, our results support that psoriatic inflammation is not dependent on TNFR1 activity but is driven by a TNFR2-dependent IL-23/IL-17 pathway activation. Thus, targeting the TNFR2 pathway may emerge as a potential next-generation therapeutic approach for psoriatic diseases.

Manganese-phenolic nanoadjuvant combines sonodynamic therapy with cGAS-STING activation for enhanced cancer immunotherapy

Dendritic cells (DCs) play a key role in the presentation of tumor antigens to initiate innate and adaptive immune responses. While the tumor microenvironment (TME) contains a network of immunosuppressive factors that inhibit the differentiation and maturation of DCs. Immunoadjuvants have been focusing on modulating DCs function to improve cancer immunotherapy. Herein, a phenolic nanoadjuvant was developed by self-assembly of the sonosensitizer polymer (PEG-b-IR), GSH inhibitor (sabutoclax), Mn2+ and TME acidic sensitive phenolic polymer (PEG-b-Pho) via metal–phenolic coordination. The combinational action of SDT-mediated ICD effect and Mn2+ promoted the activation of the cGAS-STING pathway significantly enhanced DCs maturation. Furthermore, this phenolic nanoadjuvant greatly sensitizes tumors to PD-L1 checkpoint blockade immunotherapy, resulting in efficiently inhibiting the growth of distant tumors and restraining lung metastasis. Therefore, our work provides the potential to remedy the therapeutic limitation of insufficient antitumor immunity for enhanced cancer immunotherapy.

Influence of photon, proton and carbon ion irradiation on differentiation, maturation and functionality of dendritic cells.

While the primary purpose of radiotherapy (RT) is the elimination of cancer cells by inducing DNA-damage, considerable evidence emerges that anti-neoplastic effects extend beyond mere tumor cell killing. These secondary effects are based on activation of dendritic cells (DCs) via induction of antitumoral immune reactions. However, there is an ongoing debate whether or not irradiation of the DCs themselves may negatively affect their maturation and functionality. Human monocytes were irradiated with different absorbed doses (1 × 15 Gy relative biological effectiveness (RBE), 5 × 2 Gy (RBE), 1 × 0.5 Gy (RBE)) with photons, protons and carbon ions. Differentiation and maturation of DCs were assessed by staining of corresponding cell surface molecules and functional analysis of irradiated DCs was based on in vitro analysis of phagocytosis, migration and IL-12 secretion. Irradiation of CD14-positive DCs did not alter surface phenotypes of immature DCs and mature DCs. Not only differentiation, but also functionality of immature DCs regarding phagocytosis, migration and IL-12 secretion capacity was not negatively influenced through RT with photons, protons or carbon ions as well as with different dose levels. After proton irradiation migratory capacity of immature DCs was increased. Our experiments reveal that phenotypic maturation of DCs remains unchanged after RT with different fractionations and after irradiation with particle therapy. Unaffected functionality (phagocytosis, migration and cytokine secretion) after RT of DCs indicated possible persistent potential for inducing adaptive immune response. Additional effects on the immunogenic potential of DCs will be investigated by further functional assays.

Postmortem high-dimensional immune profiling of severe COVID-19 patients reveals distinct patterns of immunosuppression and immunoactivation

A complete diagnostic autopsy is the gold-standard to gain insight into Coronavirus disease 2019 (COVID-19) pathogenesis. To delineate the in situ immune responses to SARS-CoV-2 viral infection, here we perform comprehensive high-dimensional transcriptional and spatial immune profiling in 22 COVID-19 decedents from Wuhan, China. We find TIM-3-mediated and PD-1-mediated immunosuppression as a hallmark of severe COVID-19, particularly in men, with PD-1+ cells being proximal rather than distal to TIM-3+ cells. Concurrently, lymphocytes are distal, while activated myeloid cells are proximal, to SARS-CoV-2 viral antigens, consistent with prevalent SARS-CoV-2 infection of myeloid cells in multiple organs. Finally, viral load positively correlates with specific immunosuppression and dendritic cell markers. In summary, our data show that SARS-CoV-2 viral infection induces lymphocyte suppression yet myeloid activation in severe COVID-19, so these two cell types likely have distinct functions in severe COVID-19 disease progression, and should be targeted differently for therapy.

Naringenin Regulates FKBP4/NR3C1/NRF2 Axis in Autophagy and Proliferation of Breast Cancer and Differentiation and Maturation of Dendritic Cell.

NRF2 is an important regulatory transcription factor involved in tumor immunity and tumorigenesis. In this study, we firstly identified that FKBP4/NR3C1 axis was a novel negative regulator of NRF2 in human breast cancer (BC) cells. The effect of FKBP4 appeared to be at protein level of NRF2 since it could not suppress the expression of NRF2 at mRNA level. Bioinformatics analysis and in vitro experiments further demonstrated that FKBP4 regulated NRF2 via regulating nuclear translocation of NR3C1. We then reported that naringenin, a flavonoid, widely distributed in citrus and tomato, could suppress autophagy and proliferation of BC cells through FKBP4/NR3C1/NRF2 signaling pathway in vitro and in vivo. Naringenin was also found to promote dendritic cell (DC) differentiation and maturation through FKBP4/NR3C1/NRF2 axis. Therefore, our study found that naringenin could induce inhibition of autophagy and cell proliferation in BC cells and enhance DC differentiation and maturation, at least in part, though regulation of FKBP4/NR3C1/NRF2 signaling pathway. Identification of FKBP4/NR3C1/NRF2 axis would provide insights for novel anti-tumor strategy against BC among tumor microenvironment.

The effects of 1,25(OH)2 D3 treatment on immune responses and intracellular metabolic pathways of bone marrow-derived dendritic cells from lean and obese mice.

Vitamin D affects differentiation, maturation, and activation of dendritic cells (DCs). Obesity-related immune dysfunction is associated with metabolic changes in immune cells. Objectives of the study are to investigate the effects of vitamin D and obesity on immune responses and markers related to immunometabolism of bone marrow-derived dendritic cells (BMDCs). Bone marrow cells (BMCs) were isolated from lean and obese mice, and BMDCs were generated by culturing BMCs with rmGM-CSF. BMDCs were treated with 1 or 10nM of 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ), and maturation was induced by LPS (50 ng/ml) stimulation for 24 hr. Cell phenotypes, cytokine productions, and expression of proteins and genes involved in Akt/mTOR signaling pathway and glycolytic pathway were determined. 1,25(OH)2 D3 treatment inhibited differentiation of BMDCs (CD11c+ %), expression of phenotypes related with DC function (MHC class II and CD86) and production of IL-12p70 in both lean and obese mice. The expression of PD-L1 and the ratio of IL-10/IL-12p70 were increased by 1,25(OH)2 D3 . With 1,25(OH)2 D3 treatment, Akt/mTOR signaling pathway was suppressed, and expression of genes related to glycolysis (Glut1, Pfkfb4, and Hif1A) was increased. The upregulation of glycolysis-related genes observed with 1,25(OH)2 D3 treatment seems to be associated with the induction of tolerogenic features of BMDCs from lean and obese mice, and Hif1A seems to have a potential role in conveying the effect of 1,25(OH)2 D3 on glycolysis.

PP2Cδ Controls the Differentiation and Function of Dendritic Cells Through Regulating the NSD2/mTORC2/ACLY Pathway.

Dendritic cells (DCs) are recognized as a key orchestrator of immune response and homeostasis, deregulation of which may lead to autoimmunity such as experimental autoimmune encephalomyelitis (EAE). Herein we show that the phosphatase PP2Cδ played a pivotal role in regulating DC activation and function, as PP2Cδ ablation caused aberrant maturation, activation, and Th1/Th17-priming of DCs, and hence induced onset of exacerbated EAE. Mechanistically, PP2Cδ restrained the expression of the essential subunit of mTORC2, Rictor, primarily through de-phosphorylating and proteasomal degradation of the methyltransferase NSD2 via CRL4DCAF2 E3 ligase. Loss of PP2Cδ in DCs accordingly sustained activation of the Rictor/mTORC2 pathway and boosted glycolytic and mitochondrial metabolism. Consequently, ATP-citrate lyse (ACLY) was increasingly activated and catalyzed acetyl-CoA for expression of the genes compatible with hyperactivated DCs under PP2Cδ deletion. Collectively, our findings demonstrate that PP2Cδ has an essential role in controlling DCs activation and function, which is critical for prevention of autoimmunity.

The Mechanism of Delayed Ischemic Preconditioning in Alleviating Acute Ischemia/Reperfusion Renal Injury through Treg Mediated by Immature CD11c+ Dendritic Cells

Introduction: Renal ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury, and its mechanism is complex involving multiple factors, while delayed ischemic preconditioning (DIPC) has a protective effect on the above process. In our previous study, we found that DIPC can exert its protection on renal IRI by inhibiting the maturation of dendritic cells (DCs), but the mechanism has not been clarified. This study aimed to investigate the protective mechanism of DIPC on renal IRI in mice through Treg mediated by immature DCs (imDCs). Methods: The IRI mice model, DIPC treatment, and conditional CD11c⁺ DCs (CD11c-DTR) knockout mice were used to perform our study. The maturation and differentiation of DCs and Treg cells in the kidney and spleen were analyzed by flow cytometry. HE staining was used to evaluate the pathology of the kidney tissue. The level of creatinine (Cr), oxidative stress factors (SOD, MDA), and inflammatory factors (TNF-α, IL-10, IL-4) were also measured. Then, imDCs were co-cultured with HK-2 cells, and apoptosis was analyzed with flow cytometry and PI-Hoechst 33,342 fluorescence staining to assess the apoptosis rate of HK-2 cells under hypoxic-reoxygenated (H/R) conditions. Results: DIPC could decrease renal Cr levels, alleviate pathological renal damage, and reduce oxidative stress and inflammation caused by IRI. Moreover, DIPC could decrease the number of mature DCs (mDCs) and increase Treg lymphocyte infiltration in the kidney tissue, while the reduction of DCs reversed this process. In addition, our in vitro experiment found that in the H/R model, the apoptosis of HK-2 cells decreased which were co-cultured with imDCs. Conclusion: DIPC can regulate the differentiation of DCs into imDCs, thus affecting the differentiation level and distribution of Treg cells to exert its protective effect on renal IRI.

High-Yield Monocyte, Macrophage, and Dendritic Cell Differentiation From Induced Pluripotent Stem Cells

High-Yield Monocyte, Macrophage, and Dendritic Cell Differentiation From Induced Pluripotent Stem Cells

Preservation of antigen-specific responses in cryopreserved CD4+ and CD8+ T cells expanded with IL-2 and IL-7

ObjectivesWe sought to develop medium throughput standard operating procedures for screening cryopreserved human peripheral blood mononuclear cells (PBMCs) for CD4+ and CD8+ T cell responses to potential autoantigens. MethodsDendritic cells were loaded with a peptide cocktail from ubiquitous viruses or full-length viral protein antigens and cocultured with autologous T cells. We measured expression of surface activation markers on T cells by flow cytometry and cytometry by time of flight 24–72 h later. We tested responses among T cells freshly isolated from healthy control PBMCs, cryopreserved T cells, and T cells derived from a variety of T cell expansion protocols. We also compared the transcriptional profile of CD8+ T cells rested with interleukin (IL)7 for 48 h after 1) initial thawing, 2) expansion, and 3) secondary cryopreservation/thawing of expanded cells. To generate competent antigen presenting cells from PBMCs, we promoted differentiation of PBMCs into dendritic cells with granulocyte macrophage colony stimulating factor and IL-4. ResultsWe observed robust dendritic cell differentiation from human PBMCs treated with 50 ng/mL GM-CSF and 20 ng/mL IL-4 in as little as 3 days. Dendritic cell purity was substantially increased by magnetically enriching for CD14+ monocytes prior to differentiation. We also measured antigen-dependent T cell activation in DC-T cell cocultures. However, polyclonal expansion of T cells with anti-CD3/antiCD28 abolished antigen-dependent upregulation of CD69 in our assay despite minimal transcriptional differences between rested CD8+ T cells before and after expansion. Furthermore, resting these expanded T cells in IL-2, IL-7 or IL-15 did not restore the antigen dependent responses. In contrast, T cells that were initially expanded with IL-2 + IL-7 rather than plate bound anti-CD3 + anti-CD28 retained responsiveness to antigen stimulation and these responses strongly correlated with responses measured at initial thawing. SignificanceWhile screening techniques for potential pathological autoantibodies have come a long way, comparable full-length protein target assays for screening patient T cells at medium throughput are noticeably lacking due to technical hurdles. Here we advance techniques that should have broad applicability to translational studies investigating cell mediated immunity in infectious or autoimmune diseases. Future studies are aimed at investigating possible CD8+ T cell autoantigens in MS and other CNS autoimmune diseases.

Identification of Profound Metabolic Alterations in Human Dendritic Cells by Progesterone Through Integrated Bioinformatics Analysis.

Maintaining the homeostasis of the decidual immune microenvironment at the maternal-fetal interface is essential for reproductive success. Dendritic cells (DCs) are the professional antigen-presenting cells and dominate this balance of immunogenicity and tolerance. Progesterone (P4) is highlighted as the “hormone of pregnancy” in most eutherian mammals because of its regulatory role in immune-endocrine behavior during pregnancy. Recent studies have shown that P4 is associated with the differentiation and function of DCs, however, the underlying mechanisms remain unidentified. In addition, while progress in the field of immunometabolism has highlighted the intimate connections between the metabolism phenotype and the immunogenic or tolerogenic fate of DCs, whether P4 can affect DCs metabolism and thus exert a functional manipulation has not yet been explored. In this study, we acquired human peripheral blood monocyte-derived DCs and conducted RNA sequencing (RNA-seq) on immature DCs (iDCs), P4-treated DCs (pDCs), and mature DCs (mDCs), aiming to comprehensively assess the effects of P4 on DCs. Our results showed pDCs performed a distinct differentially expressed genes (DEGs) profile compared with iDCs or mDCs. Further functional enrichment and weighted gene co-expression network (WGCNA) analysis found that these DEGs were related not only to the cellular components but also to the significant metabolic activities, including mitochondrial oxidative phosphorylation (OXPHOS) and fatty acid metabolism. In addition, these changes may be involved in the activation of various signaling pathways of PI3K/Akt/mTOR, AMPK/PGC1-α, and PPAR-γ. In summary, our work suggested that P4 induced profound metabolic alterations of mitochondrial OXPHOS and fatty acid metabolism in DCs. Our findings may provide new insights into the role of P4 in DCs.

Associations between CSF proteins and medial temporal lobe atrophy across the AD continuum

AbstractBackgroundCortical atrophy is a typical feature of Alzheimer´s disease (AD). The biological processes that associate with or possibly lead to atrophy remain largely unexplored. We hypothesized that disease stage would modulate the associations between cerebrospinal fluid (CSF) proteins and regional cortical thickness in individuals with abnormal CSF beta‐amyloid.MethodCognitively normal (CN), mild cognitive impairment (MCI) and AD individuals were selected from ADNI, based on abnormal CSF beta‐amyloid (<192 ng/l). All examined individuals had cortical thickness measurements and CSF proteomic data available (measured with MRM and RBM). Correlations between 217 CSF proteins and cortical thickness in 34 cortical regions (averaged over the left and right hemispheres) were analyzed with linear models, adjusted for age and sex. Interactions for diagnosis were evaluated for each protein‐cortical thickness association. Protein enrichment analysis was performed with Cytoscape ClueGO.ResultWe included 197 individuals (32 CN; 104 MCI; 61 AD) with a mean age 74.8 (SD 7.1) years, 41.6 % women.Cortical thickness declined according to disease progression in 28 brain regions, most significantly in the entorhinal cortex (ANOVA p‐value <0.0001), the middle temporal gyrus (p<0.0001) and the inferior temporal cortex (p<0.0001). 9 proteins, including phospho‐tau and BACE activity, showed interactions for diagnosis in the entorhinal cortex, 12 in the middle temporal gyrus and 19 inferior temporal cortex. These proteins were associated with beta‐amyloid metabolic process, dendritic cell differentiation, and oligodendrocyte development in ClueGO enrichment analyses. A consistent finding was that higher levels of the majority of these CSF proteins correlated with lower cortical thickness in CN, and that these correlations were attenuated with disease progression.ConclusionAlterations in the levels of CSF proteins are associated with cortical atrophy in the medial temporal regions, and the biological processes underlying cortical atrophy seem to begin already in the preclinical stage of AD. These results suggest that therapies targeted at preventing cortical atrophy would need to be initiated already in the CN stage.

A Sampling of Highlights from the Literature

TAMs expressing TREM2 are a potential therapeutic target (from Fig. 2F of Cao et al., Cancer Immunol Res 2019)Understanding the mechanisms underlying resistance to anti–PD-1 therapy is key to developing new therapeutics. Binnewies et al. find that human and mouse immunosuppressive tumor-associated macrophages (TAM) express triggering receptor expressed on myeloid cells 2 (TREM2) and that the presence of these cells in the tumor microenvironment correlates with an exhausted T-cell state in human tumors and anti–PD-1 resistance in mouse models of cancer. A TREM2-specific antibody promotes antitumor immunity in mice by depleting TAMs, leading to enhanced CD8+ T-cell function. It also reverses anti–PD-1 resistance, highlighting the potential of targeting TREM2 to treat patients with anti–PD-1–resistant tumors.Binnewies M, …, Sriram V. Cell Rep 2021 Oct 19;37:109844.Loss of antigen can have an impact on therapy efficacy (by Silverisdead via Flickr)Tumor loss of target antigen(s) can lead to resistance to treatments such as adoptive cell therapy and chimeric antigen receptor T-cell therapy. Xue et al. demonstrate that engineered, tumor-specific Th9 cells can overcome this hurdle and eliminate tumor cells regardless of antigen expression. This effect is due to both direct killing and induction of bystander responses driven by intratumoral accumulation of extracellular ATP—because Th9 cells lack CD39—which leads to monocyte recruitment and production of type I IFN. This study identifies a novel role of Th9 cells in antitumor responses and highlights their potential use as an “unconventional” cell type for cell-based therapy.Xue G, …, Lu Y. Cancer Cell 2021 Oct 21. DOI: 10.1016/j.ccell.2021.09.011.Engineered E. coli bacteria can improve immunotherapy (by Janice Haney Carr via PIXNIO)An increase in L-arginine concentration in tumors is associated with improved antitumor T-cell function, but modulating intratumoral L-arginine concentrations is challenging. Canale et al. engineered probiotic Escherichia coli to constitutively convert ammonia, often abundant in the tumor microenvironment, into L-arginine. Intratumoral and intravenous delivery of the engineered bacteria into tumor-bearing mice synergizes with anti–PD-L1 to improve tumor clearance and increase survival. The effect is dependent on T cells and induces long-lasting immune memory against tumor rechallenge. The advent of this synthetic biotic therapy opens a new dimension to immunotherapy-augmenting strategies for future therapeutic development.Canale FP, …, Geiger R. Nature 2021 Oct 6;598:662–6.Each ICB therapy has separate effects but can be combined to increase efficacy (by Fauxto_digit via Flickr)Immune checkpoint blockade (ICB) is effective in only some patients with melanoma, and the effects of ICB on systemic T-cell responses are not fully elucidated. Gangaev et al. analyzed ex vivo peripheral blood CD8+ T-cell responses to melanoma-associated epitopes. Patient treatment with PD-1 blockade does not affect the breadth of the responses, but anti–CTLA-4 enhances the breadth of the responses. The data highlight that ICB strategies have distinct effects and suggest that those induced by anti–PD-1 act primarily at the tumor site, supporting combinatorial use of ICB therapies.Gangaev A, …, Kvistborg P. Proc Natl Acad Sci U S A 2021 Oct 26;118:e2102849118.Ly6c+CD103+ DC differentiation from precursors is inhibited by BTK and IDO (from Fig. 6 of Neumüller et al., Intech Open 2016)The Ly6c+CD103+ dendritic cells (DC) that cross-present tumor antigens are largely absent from the tumor microenvironment. Sharma et al. find that either pharmacologic or genetic inhibition of BTK and IDO in mouse models of melanoma promotes differentiation of these DCs and antitumor activity. This occurs because the BTK–IDO axis inhibits IFNγ-induced GATOR2–mTORC1 activation, which drives differentiation of monocyte-lineage DC precursors into Ly6c+CD103+ DCs. Elucidating this pathway highlights a molecular process that may be targeted to improve immunotherapy response in tumors refractory to current treatments.Sharma MD, …, Munn DH. Immunity 2021 Oct 12;54:2354–71.e8.Microbiota promote IFN-I production in the TME (from Fig. 1C of Hakozaki et al., Cancer Immunol Res 2020)Interactions between tumor microenvironment (TME) components influence tumor development and response to therapy. Lam et al. show that microbiota-derived stimulator of interferon genes (STING) agonists induce monocytes in the TME to produce type I IFN (IFN-I), which promotes macrophage polarization toward an antitumorigenic phenotype and natural killer cell recruitment, activation, and cross-talk with dendritic cells. This IFN-I pathway is triggered and promotes antitumor immunity in mice fed a high-fiber diet or transplanted with fecal microbiota from patients with melanoma responding to immune checkpoint blockade. The data provide insight that could be used to harness microbiota to treat cancer.Lam KC, …, Goldszmid RS. Cell 2021 Oct 14;184:5338–56.e21.

Inhibiting BTK and IDO Enhances Dendritic Cell-Mediated Immune Response.

Dual inhibition of BTK and IDO promotes monocytic lineage-derived dendritic cell differentiation.

Modulation of the immune response by heterogeneous monocytes and dendritic cells in lung cancer.

Different subpopulations of monocytes and dendritic cells (DCs) may have a key impact on the modulation of the immune response in malignancy. In this review, we summarize the monocyte and DCs heterogeneity and their function in the context of modulating the immune response in cancer. Subgroups of monocytes may play opposing roles in cancer, depending on the tumour growth and progression as well as the type of cancer. Monocytes can have pro-tumour and anti-tumour functions and can also differentiate into monocyte-derived DCs (moDCs). MoDCs have a similar antigen presentation ability as classical DCs, including cross-priming, a process by which DCs activate CD8 T-cells by cross-presenting exogenous antigens. DCs play a critical role in generating anti-tumour CD8 T-cell immunity. DCs have plastic characteristics and show distinct phenotypes depending on their mature state and depending on the influence of the tumour microenvironment. MoDCs and other DC subsets have been attracting increased interest owing to their possible beneficial effects in cancer immunotherapy. This review also highlights key strategies deploying specific DC subpopulations in combination with other therapies to enhance the anti-tumour response and summarizes the latest ongoing and completed clinical trials using DCs in lung cancer.

Homeostatic IL-13 in healthy skin directs dendritic cell differentiation to promote TH2 and inhibit TH17 cell polarization.

The signals driving the adaptation of type 2 dendritic cells (DC2s) to diverse peripheral environments remain mostly undefined. We show that differentiation of CD11blo migratory DC2s-a DC2 population unique to the dermis-required IL-13 signaling dependent on the transcription factors STAT6 and KLF4, whereas DC2s in lung and small intestine were STAT6-independent. Similarly, human DC2s in skin expressed an IL-4 and IL-13 gene signature that was not found in blood, spleen and lung DCs. In mice, IL-13 was secreted homeostatically by dermal innate lymphoid cells and was independent of microbiota, TSLP or IL-33. In the absence of IL-13 signaling, dermal DC2s were stable in number but remained CD11bhi and showed defective activation in response to allergens, with diminished ability to support the development of IL-4+GATA3+ helper T cells (TH), whereas antifungal IL-17+RORγt+ TH cells were increased. Therefore, homeostatic IL-13 fosters a noninflammatory skin environment that supports allergic sensitization.

CTIM-10. REPRODUCIBILITY OF CLINICAL TRIALS USING CMV-TARGETED DENDRITIC CELL VACCINES IN PATIENTS WITH GLIOBLASTOMA

Abstract INTRODUCTION Vaccination with dendritic cells (DCs) fares poorly in primary and recurrent glioblastoma (GBM). Moreover, GBM vaccine trials are often underpowered due to limited sample size. METHODS To address these limitations, we conducted three sequential clinical trials utilizing Cytomegalovirus (CMV)-specific DC vaccines in patients with primary GBM. Autologous DCs were generated and electroporated with mRNA encoding for the CMV protein pp65. Serial vaccination was given throughout adjuvant temozolomide cycles, and 111Indium radiolabeling was implemented to assess migration efficiency of DC vaccines. Patients were followed for median overall survival (mOS) and OS. RESULTS Our initial study was the phase II ATTAC study (NCT00639639; total n=12) with 6 patients randomized to vaccine site preconditioning with tetanus-diphtheria (Td) toxoid. This led to an expanded cohort trial (ATTAC-GM; NCT00639639) of 11 patients receiving CMV DC vaccines containing granulocyte-macrophage colony-stimulating factor (GM-CSF). Follow-up data from ATTAC and ATTAC-GM revealed 5-year OS rates of 33.3% (mOS 38.3 months; CI95 17.5-undefined) and 36.4% (mOS 37.7 months; CI95 18.2-109.1), respectively. ATTAC additionally revealed a significant increase in DC migration to draining lymph nodes following Td preconditioning (P=0.049). Increased DC migration was associated with OS (Cox proportional hazards model, HR=0.820, P=0.023). Td-mediated increased migration has been recapitulated in our larger confirmatory trial ELEVATE (NCT02366728) of 43 patients randomized to preconditioning (Wilcoxon rank sum, Td n=24, unpulsed DC n=19; 24h, P=0.031 and 48h, P=0.0195). In ELEVATE, median follow-up of 42.2 months revealed significantly longer OS in patients randomized to Td (P=0.026). The 3-year OS for Td-treated patients in ELEVATE was 34% (CI95 19-63%) compared to 6% given unpulsed DCs (CI95 1-42%). CONCLUSION We report reproducibility of our findings across three sequential clinical trials using CMV pp65 DCs. Despite their small numbers, these successive trials demonstrate consistent survival outcomes, thus supporting the efficacy of CMV DC vaccine therapy in GBM.

Identification of a Novel Gene Correlated With Vascular Smooth Muscle Cells Proliferation and Migration in Chronic Thromboembolic Pulmonary Hypertension.

Objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombofibrotic obstruction of the proximal pulmonary arteries, which result in vascular remodeling of the distal pulmonary artery. While the cellular and molecular mechanisms underlying CTEPH pathogenesis remain incompletely understood, recent evidence implicates vascular remodeling. Here, we identify the molecular mechanisms that contribute to vascular remodeling in CTEPH.Methods: Microarray data (GSE130391) for patients with CTEPH and healthy controls were downloaded from the Gene Expression Omnibus (GEO) and screened for differentially expressed genes (DEGs). DEGs were functionally annotated using Gene Ontology (GO) functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. A protein–protein interaction (PPI) network was constructed to identify hub genes. Finally, pulmonary artery samples were harvested from patients with CTEPH (n = 10) and from controls (n = 10) and primary vascular smooth muscle cells (VSMCs) were cultured. Effects of the proto-oncogene FOS on VSMC proliferation and migration were assessed using expression and knockdown studies.Results: We detected a total of 292 DEGs, including 151 upregulated and 141 downregulated genes. GO analysis revealed enrichment of DEGs in biological processes of signal transduction, response to lipopolysaccharide, signal transduction, and myeloid dendritic cell differentiation. Molecular function analysis revealed enrichment in tumor necrosis factor (TNF)-activated receptor activity, transcriptional activator activity, and protein homodimerization activity. The expression of TNF-α and its receptor (sTNFR1 and sTNFR2) were significantly higher in CTEPH group, compared with control group. KEGG pathway analysis revealed enrichment in salmonella infection, pathways in cancer, osteoclast differentiation, and cytokine-cytokine receptor interaction. Hub genes in the PPI included FOS, suggesting an important role for this gene in vascular remodeling in CTEPH. Primary VSMCs derived from patients with CTEPH showed increased FOS expression and high proliferation and migration, which was attenuated by FOS inhibition. In control VSMCs, TNF-α treatment increased proliferation and migration, which FOS inhibition likewise attenuated.Conclusion: TNF-α drives CTEPH pathogenesis by promoting VSMC proliferation and migration via increased FOS expression. These results advance our understanding of the molecular mechanisms of vascular remodeling in CTEPH, and may inform the development of new therapeutic targets.