RATIONALE:Atherosclerosis is a chronic inflammatory disease that is driven by the interplay of pro- and anti-inflammatory leukocytes in the aorta. Yet, the phenotypic and transcriptional diversity of ...aortic leukocytes is only poorly understood.
OBJECTIVE:We characterized leukocytes from healthy and atherosclerotic mouse aortas in-depth by single cell RNA-sequencing (scRNAseq) and mass cytometry (CyTOF) to define an atlas of the immune cell landscape in atherosclerosis.
METHODS AND RESULTS:Employing scRNAseq of aortic leukocytes from chow (CD) and western diet (WD) fed Apoe and Ldlr mice, we detected 11 principal leukocyte clusters with distinct phenotypical and spatial characteristics, while the cellular repertoire in healthy aortas was less diverse. Gene set enrichment analysis on a single cell level established that multiple pathways, such as for lipid metabolism, proliferation, and cytokine secretion, were confined to particular leukocyte clusters. Leukocyte populations were differentially regulated in atherosclerotic Apoe and Ldlr mice. We confirmed the phenotypic diversity of these clusters with a novel CyTOF 35-marker panel with metal-labelled antibodies and conventional flow cytometry. Cell populations retrieved by these protein-based approaches were highly correlated to transcriptionally defined clusters. In an integrated screening strategy of scRNAseq, CyTOF, and FACS, we detected three principal B-cell subsets with alterations in surface markers, functional pathways, and in vitro cytokine secretion. Finally, we used leukocyte cluster gene signatures to enumerate leukocyte frequencies in 126 human plaques by a genetic deconvolution strategy. This approach revealed that human carotid plaques and microdissected mouse plaques were mostly populated by macrophages, T-cells, and monocytes. In addition, the frequency of genetically defined leukocyte populations in carotid plaques predicted cardiovascular events in patients.
CONCLUSIONS:The definition of leukocyte diversity by high-dimensional analyses enables a fine-grained analysis of aortic leukocyte subsets, reveals new immunological mechanisms and cell-type specific pathways, and establishes a functional relevance for lesional leukocytes in human atherosclerosis.
Danger-associated molecular patterns derived from damaged or dying cells elicit inflammation and potentiate antitumor immune responses. In this article, we show that treatment of breast cancer cells ...with the antitumor agent topotecan (TPT), an inhibitor of topoisomerase I, induces danger-associated molecular pattern secretion that triggers dendritic cell (DC) activation and cytokine production. TPT administration inhibits tumor growth in tumor-bearing mice, which is accompanied by infiltration of activated DCs and CD8
T cells. These effects are abrogated in mice lacking STING, an essential molecule in cytosolic DNA-mediated innate immune responses. Furthermore, TPT-treated cancer cells release exosomes that contain DNA that activate DCs via STING signaling. These findings suggest that a STING-dependent pathway drives antitumor immunity by responding to tumor cell-derived DNA.
Oncolytic reovirus, which possesses 10 segments of dsRNA genome, mediates antitumor effects via not only virus replication in a tumor cell-specific manner, but also activation of antitumor immunity; ...however, the mechanism(s) of reovirus-induced activation of antitumor immunity have not been fully elucidated. Recent studies have demonstrated that overcoming an immunosuppressive environment in tumor-bearing hosts is important to achieve efficient activation of antitumor immunity. Among the various types of cells involved in immunosuppression, it has been revealed that myeloid-derived suppressor cells (MDSCs) are significantly increased in tumor-bearing hosts and play crucial roles in the immunosuppression in tumor-bearing hosts. In this study, we examined whether reovirus inhibits the immunosuppressive activity of MDSCs, resulting in efficient activation of immune cells after in vivo administration. The results showed that splenic MDSCs recovered from PBS-treated tumor-bearing mice significantly suppressed the Ag-specific proliferation of CD8
T cells. In contrast, the suppressive activity of MDSCs on T cell proliferation was significantly reduced after reovirus administration. Reovirus also inhibited the immunosuppressive activity of MDSCs in IFN-β promoter stimulator-1 knockout (KO) mice and in wild-type mice. In contrast, the immunosuppressive activity of MDSCs in TLR-3 KO mice was not significantly altered by reovirus treatment. The activation levels of CD4
and CD8
T cells were significantly lower in TLR3 KO mice than in wild-type mice after reovirus administration. These results indicate that reovirus inhibits the immunosuppressive activity of MDSCs in a TLR3, but not IFN-β promoter stimulator-1, signaling-dependent manner.
Aluminum-based adjuvants (aluminum salts or alum) are widely used in human vaccination, although their mechanisms of action are poorly understood. Here we report that, in mice, alum causes cell death ...and the subsequent release of host cell DNA, which acts as a potent endogenous immunostimulatory signal mediating alum adjuvant activity. Furthermore, we propose that host DNA signaling differentially regulates IgE and IgG1 production after alum-adjuvanted immunization. We suggest that, on the one hand, host DNA induces primary B cell responses, including IgG1 production, through interferon response factor 3 (Irf3)-independent mechanisms. On the other hand, we suggest that host DNA also stimulates 'canonical' T helper type 2 (T(H)2) responses, associated with IgE isotype switching and peripheral effector responses, through Irf3-dependent mechanisms. The finding that host DNA released from dying cells acts as a damage-associated molecular pattern that mediates alum adjuvant activity may increase our understanding of the mechanisms of action of current vaccines and help in the design of new adjuvants.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Caspase recruitment domain family member 14 (CARD14) was recently identified as a psoriasis-susceptibility gene, but its immunological role in the pathogenesis of psoriasis in vivo remains unclear. ...In this study, we examined the role of CARD14 in murine experimental models of psoriasis induced by either imiquimod (IMQ) cream or recombinant IL-23 injection. In all models tested, the psoriasiform skin inflammation was abrogated in
mice. Comparison of the early gene signature of the skin between IMQ-cream-treated
mice and
mice revealed not only their similarity, but also distinct gene sets targeted by IL-23. Cell type-specific analysis of these mice identified skin Langerin
Langerhans cells as a potent producer of IL-23, which was dependent on both TLR7 and TLR9 but independent of CARD14, suggesting that CARD14 is acting downstream of IL-23, not TLR7 or TLR9. Instead, a bone marrow chimera study suggested that CARD14 in radio-sensitive hematopoietic cells was required for IMQ-induced psoriasiform skin inflammation, controlling the number of Vγ4
T cells producing IL-17 or IL-22 infiltrating through the dermis to the inflamed epidermis. These data indicate that CARD14 is essential and a potential therapeutic target for psoriasis.
Agonists for TLR9 and Stimulator of IFN Gene (STING) act as vaccine adjuvants that induce type‐1 immune responses. However, currently available CpG oligodeoxynucleotide (ODN) (K‐type) induces IFNs ...only weakly and STING ligands rather induce type‐2 immune responses, limiting their potential therapeutic applications. Here, we show a potent synergism between TLR9 and STING agonists. Together, they make an effective type‐1 adjuvant and an anticancer agent. The synergistic effect between CpG ODN (K3) and STING‐ligand cyclic GMP–AMP (cGAMP), culminating in NK cell IFN‐γ (type‐II IFN) production, is due to the concurrent effects of IL‐12 and type‐I IFNs, which are differentially regulated by IRF3/7, STING, and MyD88. The combination of CpG ODN with cGAMP is a potent type‐1 adjuvant, capable of inducing strong Th1‐type responses, as demonstrated by enhanced antigen‐specific IgG2c and IFN‐γ production, as well as cytotoxic CD8+ T‐cell responses. In our murine tumor models, intratumoral injection of CpG ODN and cGAMP together reduced tumor size significantly compared with the singular treatments, acting as an antigen‐free anticancer agent. Thus, the combination of CpG ODN and a STING ligand may offer therapeutic application as a potent type‐II IFN inducer.
Spike protein mutation Leu455Ser is a hallmark mutation of JN.1: we have recently shown that HK.3 and other flip variants carry Leu455Phe, which contributes to increased transmissibility and immune ...escape ability compared with the parental EG.5.1 variant.5 Here, we investigated the virological properties of JN.1. KJI and KS are supported in part by AMED SCARDA Japan Initiative for World-leading Vaccine Research and Development Centers UTOPIA and by AMED SCARDA Program on R&D of new generation vaccine including new modality application. KS received funding from the AMED Research Program on HIV/AIDS, JST CREST, JSPS Core-to-Core Program, The Tokyo Biochemical Research Foundation, and The Mitsubishi Foundation; received consulting fees from Moderna Japan and Takeda Pharmaceutical; and honoraria for lectures from Gilead Sciences, Moderna Japan, and Shionogi & Co. JI received funding from JST PRESTO and JSPS KAKENHI Grant-in-Aid for Early-Career Scientists; and received consulting fees and honoraria for lectures from Takeda Pharmaceutical.
Although checkpoint inhibitors (CPIs) have changed the paradigm of cancer therapy, low response rates and serious systemic adverse events remain challenging. In situ vaccine (ISV), intratumoral ...injection of immunomodulators that stimulate innate immunity at the tumor site, allows for the development of vaccines in patients themselves. K3-SPG, a second-generation nanoparticulate Toll-like receptor 9 (TLR9) ligand consisting of K-type CpG oligodeoxynucleotide (ODN) wrapped with SPG (schizophyllan), integrates the best of conventional CpG ODNs, making it an ideal cancer immunotherapy adjuvant. Focusing on clinical feasibility for pancreaticobiliary and gastrointestinal cancers, we investigated the antitumor activity of K3-SPG-ISV in preclinical models of pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC). K3-SPG-ISV suppressed tumor growth more potently than K3-ISV or K3-SPG intravenous injections, prolonged survival, and enhanced the antitumor effect of CPIs. Notably, in PDAC model, K3-SPG-ISV alone induced systemic antitumor effect and immunological memory. ISV combination of K3-SPG and agonistic CD40 antibody further enhanced the antitumor effect. Our results imply that K3-SPG-based ISV can be applied as monotherapy or combined with CPIs to improve their response rate or, conversely, with CPI-free local immunotherapy to avoid CPI-related adverse events. In either strategy, the potency of K3-SPG-based ISV would provide the rationale for its clinical application to puncturable pancreaticobiliary and gastrointestinal malignancies.
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