Plasmacytoid dendritic cells (pDCs) are sensor cells with diverse immune functions, from type I interferon (IFN-I) production to antigen presentation, T cell activation, and tolerance. Regulation of ...these functions remains poorly understood but could be mediated by functionally specialized pDC subpopulations. We address pDC diversity using a high-dimensional single-cell approach: mass cytometry (CyTOF). Our analysis uncovers a murine pDC-like population that specializes in antigen presentation with limited capacity for IFN-I production. Using a multifaceted cross-species comparison, we show that this pDC-like population is the definitive murine equivalent of the recently described human AXL+ DCs, which we unify under the name transitional DCs (tDCs) given their continuum of pDC and cDC2 characteristics. tDCs share developmental traits with pDCs, as well as recruitment dynamics during viral infection. Altogether, we provide a framework for deciphering the function of pDCs and tDCs during diseases, which has the potential to open new avenues for therapeutic design.
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•We identify the murine homolog of human AXL+ DCs, now called transitional DCs (tDCs)•tDC development depends on Tcf4, similar to pDCs•tDCs are inefficient at IFN-I production but can efficiently activate T cells•During influenza infection, tDCs and pDCs accumulate in the lung
Dendritic cells (DCs) are unique therapeutic targets given their capacity to modulate immune responses. Yet complete alignment of the DC network between species is lacking. Using a multi-dimensional approach, Leylek et al. identify the mouse homolog of human AXL+ DCs, named transitional DCs (tDCs), and reveal their similarities with pDCs.
DNA methylation is considered to be a relatively stable epigenetic mark. However, a growing body of evidence indicates that DNA methylation levels can change rapidly; for example, in innate immune ...cells facing an infectious agent. Nevertheless, the causal relationship between changes in DNA methylation and gene expression during infection remains to be elucidated. Here, we generated time-course data on DNA methylation, gene expression, and chromatin accessibility patterns during infection of human dendritic cells with Mycobacterium tuberculosis. We found that the immune response to infection is accompanied by active demethylation of thousands of CpG sites overlapping distal enhancer elements. However, virtually all changes in gene expression in response to infection occur before detectable changes in DNA methylation, indicating that the observed losses in methylation are a downstream consequence of transcriptional activation. Footprinting analysis revealed that immune-related transcription factors (TFs), such as NF-κB/Rel, are recruited to enhancer elements before the observed losses in methylation, suggesting that DNA demethylation is mediated by TF binding to cis-acting elements. Collectively, our results show that DNA demethylation plays a limited role to the establishment of the core regulatory program engaged upon infection.
Cardiovascular disease is the leading cause of mortality worldwide, and atherosclerosis the principal factor underlying cardiovascular events. Atherosclerosis is a chronic inflammatory disease ...characterized by endothelial dysfunction, intimal lipid deposition, smooth muscle cell proliferation, cell apoptosis and necrosis, and local and systemic inflammation, involving key contributions to from innate and adaptive immunity. The balance between proatherogenic inflammatory and atheroprotective anti-inflammatory responses is modulated by a complex network of interactions among vascular components and immune cells, including monocytes, macrophages, dendritic cells, and T, B, and foam cells; these interactions modulate the further progression and stability of the atherosclerotic lesion. In this review, we take a global perspective on existing knowledge about the pathogenesis of immune responses in the atherosclerotic microenvironment and the interplay between the major innate and adaptive immune factors in atherosclerosis. Studies such as this are the basis for the development of new therapies against atherosclerosis.
Summary
Dendritic cells (DC) are a class of bone‐marrow‐derived cells arising from lympho‐myeloid haematopoiesis that form an essential interface between the innate sensing of pathogens and the ...activation of adaptive immunity. This task requires a wide range of mechanisms and responses, which are divided between three major DC subsets: plasmacytoid DC (pDC), myeloid/conventional DC1 (cDC1) and myeloid/conventional DC2 (cDC2). Each DC subset develops under the control of a specific repertoire of transcription factors involving differential levels of IRF8 and IRF4 in collaboration with PU.1, ID2, E2‐2, ZEB2, KLF4, IKZF1 and BATF3. DC haematopoiesis is conserved between mammalian species and is distinct from monocyte development. Although monocytes can differentiate into DC, especially during inflammation, most quiescent tissues contain significant resident populations of DC lineage cells. An extended range of surface markers facilitates the identification of specific DC subsets although it remains difficult to dissociate cDC2 from monocyte‐derived DC in some settings. Recent studies based on an increasing level of resolution of phenotype and gene expression have identified pre‐DC in human blood and heterogeneity among cDC2. These advances facilitate the integration of mouse and human immunology, support efforts to unravel human DC function in vivo and continue to present new translational opportunities to medicine.
A review of human DC subsets incorporating recent studies on their origins, functions and transcriptional profiles.
The method of choice for the development of new vaccines is to target distinct dendritic cell subsets with antigen in vivo and to harness their function in situ to enhance cell-mediated immunity or ...induce tolerance to specific antigens. The innate functions of dendritic cells themselves may also be targeted by inhibitors or activators that would target a specific function such as interferon production, potentially important in autoimmune disease and chronic viral infections. Importantly targeting dendritic cells requires detailed knowledge of both the surface phenotype and function of each dendritic cell subset, including how they may respond to different types of vaccine adjuvants, their ability to produce soluble mediators and to process and present antigens and induce priming of naïve T cells. This review summarizes our knowledge of the functional attributes of the human dendritic cell subsets in the steady state and upon activation and their roles in human disease.
After entering tissues, monocytes differentiate into cells that share functional features with either macrophages or dendritic cells (DCs). How monocyte fate is directed toward monocyte-derived ...macrophages (mo-Macs) or monocyte-derived DCs (mo-DCs) and which transcription factors control these differentiation pathways remains unknown. Using an in vitro culture model yielding human mo-DCs and mo-Macs closely resembling those found in vivo in ascites, we show that IRF4 and MAFB were critical regulators of monocyte differentiation into mo-DCs and mo-Macs, respectively. Activation of the aryl hydrocarbon receptor (AHR) promoted mo-DC differentiation through the induction of BLIMP-1, while impairing differentiation into mo-Macs. AhR deficiency also impaired the in vivo differentiation of mouse mo-DCs. Finally, AHR activation correlated with mo-DC infiltration in leprosy lesions. These results establish that mo-DCs and mo-Macs are controlled by distinct transcription factors and show that AHR acts as a molecular switch for monocyte fate specification in response to micro-environmental factors.
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•IRF4 and MAFB are essential for human mo-DC and mo-Mac differentiation, respectively•AHR activation promotes mo-DC and inhibits mo-Mac differentiation through BLIMP-1•AhR is involved in the in vivo differentiation of mo-DCs in the mouse
How monocytes differentiate into dendritic cells versus macrophages is poorly understood. Goudot et al. show that IRF4 and MAFB are essential for dendritic cell or macrophage differentiation, respectively, and identify aryl hydrocarbon receptor as a major regulator of monocyte fate.
The role of dendritic cells in cancer Lee, Yoke Seng; Radford, Kristen J
International review of cell and molecular biology,
2019, Letnik:
348
Journal Article
Recenzirano
Cancer immunotherapy harnesses the ability of the immune system to recognize and eliminate cancer. The potent ability of dendritic cells (DCs) to initiate and regulate adaptive immune responses ...underpins the successful generation of anti-tumor immune responses. DCs are a heterogeneous leukocyte population comprised of distinct subsets that drive specific types of immune responses. Understanding how DCs induce tumor immune responses and the mechanisms adopted by tumors to evade DC surveillance is essential to render immunotherapies more effective. This review discusses current knowledge of the roles played by different DC subsets in human cancer and how these might be manipulated as new immunotherapeutics to improve CD8
T cell-mediated immune responses, with a particular focus on the conventional type 1 DCs (cDC1).
Dendritic cells (DCs) form a remarkable cellular network that shapes adaptive immune responses according to peripheral cues. After four decades of research, we now know that DCs arise from a ...hematopoietic lineage distinct from other leukocytes, establishing the DC system as a unique hematopoietic branch. Recent work has also established that tissue DCs consist of developmentally and functionally distinct subsets that differentially regulate T lymphocyte function. This review discusses major advances in our understanding of the regulation of DC lineage commitment, differentiation, diversification, and function in situ.
Plasmacytoid dendritic cells (pDCs) are found in the CNS during neuroinflammation and have been reported to exert regulatory functions in multiple sclerosis (MS) and its animal model experimental ...autoimmune encephalomyelitis (EAE). However, the mechanisms of entry of pDCs into the CNS as well as their phenotype and innate functional properties, once recruited into the CNS, have not been thoroughly examined. Herein, we show that pDCs rapidly accumulate into the brain and spinal cord during the acute phase of EAE, and maintain the expression of numerous phenotypic markers typical of peripheral pDCs. Functionally, CNS‐pDCs constitutively expressed IRF7 and were able to rapidly produce type I IFNs and IL‐12p40 upon ex vivo TLR‐9 stimulation. Using adoptive transfer experiments, we provide evidence that CNS‐pDC are recruited from the blood and accumulate into the CNS during the acute phase of EAE. Accumulation of pDCs into the CNS was strongly inhibited in the absence of CD29, but not CD18, suggesting a major role for ß1 but not ß2 integrins. Indeed, blocking the CD49d α4‐integrins during acute EAE drastically diminished CNS‐pDC numbers. Together, our results demonstrate that circulating pDCs are actively recruited into the CNS during acute EAE through a mechanism largely dependent on CD49d/CD29‐integrins.
Accumulation of circulating pDCs into the CNS occurs during the acute phase of EAE.
CD29‐deficiency, but not CD18, significantly diminished accumulation of pDC into the CNS of EAE mice.
Blood‐derived pDCs solely rely on the expression of CD29 integrins to efficiently enter into the CNS during EAE.
Microbial infections are recognized by the innate immune system both to elicit immediate defense and to generate long-lasting adaptive immunity. To detect and respond to vastly different groups of ...pathogens, the innate immune system uses several recognition systems that rely on sensing common structural and functional features associated with different classes of microorganisms. These recognition systems determine microbial location, viability, replication and pathogenicity. Detection of these features by recognition pathways of the innate immune system is translated into different classes of effector responses though specialized populations of dendritic cells. Multiple mechanisms for the induction of immune responses are variations on a common design principle wherein the cells that sense infections produce one set of cytokines to induce lymphocytes to produce another set of cytokines, which in turn activate effector responses. Here we discuss these emerging principles of innate control of adaptive immunity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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