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Frontiers in Immunology 2018Psoriasis is a common skin disease that presents with well-demarcated patches of inflammation. Recurrent disease in fixed areas of the skin indicates a localized disease... (Review)
Review
Psoriasis is a common skin disease that presents with well-demarcated patches of inflammation. Recurrent disease in fixed areas of the skin indicates a localized disease memory that is preserved in resolved lesions. In line with such concept, the involvement of tissue-resident immune cells in psoriasis pathology is increasingly appreciated. Langerhans cells (LCs) are perfectly placed to steer resident T cells and local tissue responses in psoriasis. Here, we present an overview of the current knowledge of LCs in human psoriasis, including findings that highlight pro-inflammatory features of LCs in psoriasis lesions. We also review the literature on conflicting data regarding LC localization and functionality in psoriasis. Our review highlights that further studies are needed to elucidate the molecular mechanisms that drive LCs functionality in inflammatory diseases.
Topics: Humans; Langerhans Cells; Psoriasis
PubMed: 29520279
DOI: 10.3389/fimmu.2018.00300 -
Cancer Immunology Research Jun 2020Langerhans cell histiocytosis (LCH) is a rare disorder characterized by tissue accumulation of CD1aCD207 LCH cells. In LCH, somatic mutations of the gene have been...
Langerhans cell histiocytosis (LCH) is a rare disorder characterized by tissue accumulation of CD1aCD207 LCH cells. In LCH, somatic mutations of the gene have been detected in tissue LCH cells, bone marrow CD34 hematopoietic stem cells, circulating CD14 monocytes, and BDCA1 myeloid dendritic cells (DC). Targeting in clonal Langerhans cells (LC) and their precursors is a potential treatment option for patients whose tumors have the mutation. The development of mouse macrophages and LCs is regulated by the CSF1 receptor (CSF1R). In patients with diffuse-type tenosynovial giant cell tumors, CSF1R inhibition depletes tumor-associated macrophages (TAM) with therapeutic efficacy; however, CSF1R signaling in LCs and LCH has not been investigated. We found through IHC and flow cytometry that CSF1R is normally expressed on human CD1aCD207 LCs in the epidermis and stratified epithelia. LCs that were differentiated from CD14 monocytes, BDCA1 DCs, and CD34 cord blood progenitors expressed CSF1R that was downregulated upon maturation. Immature LCs migrated toward CSF1, but not IL34. Administration of the c-FMS/CSF1R kinase inhibitors GW2580 and BLZ945 significantly reduced human LC migration. In LCH clinical samples, LCH cells (including cells) and TAMs retained high expression of CSF1R. We also detected the presence of transcripts for its ligand, CSF1, but not IL34, in all tested LCH cases. CSF1R and CSF1 expression in LCH, and their role in LC migration and differentiation, suggests CSF1R signaling blockade as a candidate rational approach for treatment of LCH, including the and wild-type forms of the disease.
Topics: Adolescent; Adult; Aged; Apoptosis; Cell Differentiation; Cell Lineage; Cell Movement; Cells, Cultured; Child; Child, Preschool; Dendritic Cells; Female; Histiocytosis, Langerhans-Cell; Humans; Infant; Infant, Newborn; Langerhans Cells; Male; Middle Aged; Monocytes; Receptor, Macrophage Colony-Stimulating Factor; Tumor Microenvironment; Young Adult
PubMed: 32238382
DOI: 10.1158/2326-6066.CIR-19-0232 -
Medicine Feb 2020Langerhans cells (LCs) and plasmacytoid dendritic cells (pDCs) play an important role in the cutaneous immune response to viral infection. Verruca vulgaris (VV) is a...
Langerhans cells (LCs) and plasmacytoid dendritic cells (pDCs) play an important role in the cutaneous immune response to viral infection. Verruca vulgaris (VV) is a chronic benign disease caused by human papillomavirus (HPV) infection.To investigate the possible roles of LCs, pDCs and toll-like receptor (TLR)7/9 signaling pathways in the pathogenesis of VV, we detected the expression of CD1a, CD2AP, CD123, TLR7/9, IFN regulatory factor 7 (IRF7), and interleukin-1 receptor-associated kinase 1 (IRAK1) in VV lesions.The expression of CD1a, CD2AP, CD123, TLR7/9, IRF7, and IRAK1 in 20 VV lesions was tested by immunohistochemistry. The density and number of stained cells were compared between VV lesions and the perilesional normal skin.The density and number of CD1a-, CD2AP-, CD123-, TLR9-, and IRAK1-positive cells in the papillary layer of VV lesions were significantly higher than those in the perilesional normal skin (P < .05). There were no significant differences in the density and positive rate of CD1a+ cells in the epidermis and of TLR7 and IRF7 cells in the dermis between VV lesions and the perilesional normal skin at the edge (P > .05).In VV, the number of LCs increases only in the dermis, indicating that LC's antigen-presenting function might not be inhibited. The increased number of pDCs in VV lesions suggests that HPV infection may recruit the pDCs to the virus-infected epithelium. We speculate that the TLR7/9 downstream signaling pathway is not fully activated in VV, leading to difficulty of HPV removal and the relapse of HPV-infected lesions.
Topics: Adolescent; Adult; Dendritic Cells; Female; Humans; Inflammation Mediators; Langerhans Cells; Male; Signal Transduction; Toll-Like Receptor 7; Toll-Like Receptor 9; Toll-Like Receptors; Warts; Young Adult
PubMed: 32080113
DOI: 10.1097/MD.0000000000019214 -
Allergy Jun 2016Langerhans cells (LC) represent a specialized subset of evolutionarily conserved dendritic cells (DC) that populate stratified epithelial tissues, which are essential... (Review)
Review
Langerhans cells (LC) represent a specialized subset of evolutionarily conserved dendritic cells (DC) that populate stratified epithelial tissues, which are essential for the induction of skin and mucosal immunity and tolerance, including allergy. Transforming growth factor-β1 (TGF-β1) has been confirmed to be a predominant factor involved in LC development. Despite great advances in the understanding of LC ontogeny and diverse replenishment patterns, the underlying molecular mechanisms remain elusive. This review focuses on the recent discoveries in TGF-β1-mediated LC development and maintenance, with special attention to the involved transcription factors and related regulators.
Topics: Animals; Cell Differentiation; Gene Expression Regulation; Humans; Langerhans Cells; Protein Binding; Transcription Factors; Transcription, Genetic; Transforming Growth Factor beta1
PubMed: 26948524
DOI: 10.1111/all.12871 -
PloS One 2021For their functions of insulin biosynthesis and glucose- and fatty acid- mediated insulin secretion, Langerhans β-cells require an intracellular milieu rich in oxygen....
BACKGROUND
For their functions of insulin biosynthesis and glucose- and fatty acid- mediated insulin secretion, Langerhans β-cells require an intracellular milieu rich in oxygen. This requirement makes β-cells, with their constitutively low antioxidative defense, susceptible to the oxidative stress. Although much progress has been made in identifying its molecular basis in experimental systems, whether the oxidative stress due to excessive fatty acids plays a crucial role in the Langerhans cell degeneration in primates is still debated.
METHODS
Focusing on Hsp70.1, which has dual functions as molecular chaperone and lysosomal stabilizer, the mechanism of lipotoxicity to Langerhans cells was studied using macaque monkeys after the consecutive injections of the lipid peroxidation product 'hydroxynonenal'. Based on the 'calpain-cathepsin hypothesis' formulated in 1998, calpain activation, Hsp70.1 cleavage, and lysosomal integrity were studied by immunofluorescence histochemistry, electron microscopy, and Western blotting.
RESULTS
Light microscopy showed more abundant vacuole formation in the hydroxynonenal-treated islet cells than the control cells. Electron microscopy showed that vacuolar changes, which were identified as enlarged rough ER, occurred mainly in β-cells followed by δ-cells. Intriguingly, both cell types showed a marked decrease in insulin and somatostatin granules. Furthermore, they exhibited marked increases in peroxisomes, autophagosomes/autolysosomes, lysosomal and peroxisomal membrane rupture/permeabilization, and mitochondrial degeneration. Disrupted peroxisomes were often localized in the close vicinity of degenerating mitochondria or autolysosomes. Immunofluorescence histochemical analysis showed an increased co-localization of activated μ-calpain and Hsp70.1 with the extralysosomal release of cathepsin B. Western blotting showed increases in μ-calpain activation, Hsp70.1 cleavage, and expression of the hydroxynonenal receptor GPR109A.
CONCLUSIONS
Taken together, these data implicate hydroxynonenal in both oxidation of Hsp70.1 and activation of μ-calpain. The calpain-mediated cleavage of the carbonylated Hsp70.1, may cause lysosomal membrane rupture/permeabilization. The low defense of primate Langerhans cells against hydroxynonenal and peroxisomally-generated hydrogen peroxide, was presumably overwhelmed to facilitate cell degeneration.
Topics: Animals; Cell Death; Female; Langerhans Cells; Lipid Peroxidation; Macaca fuscata; Pancreas
PubMed: 34748564
DOI: 10.1371/journal.pone.0245702 -
Brain, Behavior, and Immunity Nov 2013Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis,... (Review)
Review
Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis, rosacea and acne; are widely believed to be exacerbated by stress. A growing body of research now suggests that neuropeptides and neurotransmitters serve as a link between these two systems. Neuropeptides and neurotransmitters are released by nerves innervating the skin to influence important actors of the immune system, such as Langerhans cells and mast cells, which are located within close anatomic proximity. Catecholamines and other sympathetic transmitters that are released in response to activation of the sympathetic nervous system are also able to reach the skin and affect immune cells. Neuropeptides appear to direct the outcome of Langerhans cell antigen presentation with regard to the subtypes of Th cells generated and neuropeptides induce the degranulation of mast cells, among other effects. Additionally, endothelial cells, which release many inflammatory mediators and express cell surface molecules that allow leukocytes to exit the bloodstream, appear to be regulated by certain neuropeptides and transmitters. This review focuses on the evidence that products of nerves have important regulatory activities on antigen presentation, mast cell function and endothelial cell biology. These activities are highly likely to have clinical and therapeutic relevance.
Topics: Animals; Humans; Langerhans Cells; Neuropeptides; Neurotransmitter Agents; Peripheral Nerves
PubMed: 23517710
DOI: 10.1016/j.bbi.2013.03.006 -
Acta Physiologica (Oxford, England) Mar 2015Calcitonin gene-related peptide (CGRP) has been viewed as a neuropeptide and vasodilator. However, CGRP is more appropriately thought of as a pleiotropic signalling... (Review)
Review
Calcitonin gene-related peptide (CGRP) has been viewed as a neuropeptide and vasodilator. However, CGRP is more appropriately thought of as a pleiotropic signalling molecule. Indeed, CGRP has key regulatory functions on immune and inflammatory processes within the skin. CGRP-containing nerves are intimately associated with epidermal Langerhans cells (LCs), and CGRP has profound regulatory effects on Langerhans cell antigen-presenting capability. When LCs are exposed to CGRP in vitro, their ability to present antigen for in vivo priming of naïve mice or elicitation of delayed-type hypersensitivity is inhibited in at least some situations. Administration of CGRP intradermally inhibits acquisition of immunity to Th1-dominant haptens applied to the injected site while augmenting immunity to Th2-dominant haptens, although the cellular targets of activity in these experiments remain unclear. Although CGRP can be a pro-inflammatory agent, several studies have demonstrated that administration of CGRP can inhibit the elicitation of inflammation by inflammatory stimuli in vivo. In this regard, CGRP inhibits the release of certain chemokines by stimulated endothelial cells. This is likely to be physiologically relevant as cutaneous blood vessels are innervated by sensory nerves. Exciting new studies suggest a significant role for CGRP in the pathogenesis of psoriasis and, most strikingly, that CGRP inhibits the ability of LCs to transmit the human immunodeficiency virus 1 to T lymphocytes. A more complete understanding of the role of CGRP in the skin immune system may lead to new and novel approaches for the therapy of immune-mediated skin disorders.
Topics: Animals; Calcitonin Gene-Related Peptide; Endothelial Cells; HIV Infections; Humans; Immunity, Innate; Inflammation; Langerhans Cells; Neurons; Signal Transduction; Skin
PubMed: 25534428
DOI: 10.1111/apha.12442 -
The Journal of Investigative Dermatology Jan 2021Langerhans cells (LCs) in the skin are a first line of defense against pathogens but also play an essential role in skin homeostasis. Their exclusive expression of the... (Review)
Review
Langerhans cells (LCs) in the skin are a first line of defense against pathogens but also play an essential role in skin homeostasis. Their exclusive expression of the C-type lectin receptor Langerin makes them prominent candidates for immunotherapy. For vaccine testing, an easily accessible cell platform would be desirable as an alternative to the time-consuming purification of LCs from human skin. Here, we present such a model and demonstrate that monocytes in the presence of GM-CSF, TGF-β1, and the Notch ligand DLL4 differentiate within 3 days into CD1aLangerincells containing Birbeck granules. RNA sequencing of these monocyte-derived LCs (moLCs) confirmed gene expression of LC-related molecules, pattern recognition receptors, and enhanced expression of genes involved in the antigen-presenting machinery. On the protein level, moLCs showed low expression of costimulatory molecules but prominent expression of C-type lectin receptors. MoLCs can be matured, secrete IL-12p70 and TNF-α, and stimulate proliferation and cytokine production in allogeneic CD4 and CD8 T cells. In regard to vaccine testing, a recently characterized glycomimetic Langerin ligand conjugated to liposomes demonstrated specific and fast internalization into moLCs. Hence, these short-term in vitro‒generated moLCs represent an interesting tool to screen LC-based vaccines in the future.
Topics: Cell Differentiation; Cells, Cultured; Dendritic Cells; Humans; Langerhans Cells; Lymphocyte Activation; Monocytes; Phenotype; Skin
PubMed: 32522485
DOI: 10.1016/j.jid.2020.05.098 -
The Journal of Investigative Dermatology Mar 1965
Topics: Cell Biology; Cell Physiological Phenomena; Chromatophores; Electrons; Histological Techniques; Langerhans Cells; Melanins; Microscopy; Microscopy, Electron; Skin
PubMed: 14275697
DOI: 10.1038/jid.1965.35 -
Cellular and Molecular Life Sciences :... Mar 2009Langerhans cells are immature skin-homing dendritic cells that furnish the epidermis with an immune surveillance system, and translate information between the internal... (Review)
Review
Langerhans cells are immature skin-homing dendritic cells that furnish the epidermis with an immune surveillance system, and translate information between the internal and external milieu. Dendritic cells, in particular Langerhans cells, are gaining prominence as one of the potential principal players orchestrating the decision between immunity and tolerance. Langerhans cells capture aberrant self-antigen and pathogen-derived antigen for display to the efferent immune response. Recent evidence suggests redundancy in the antigen-presenting function of Langerhans cells, with dermal dendritic subsets capable of fulfilling an analogous role. There is mounting evidence that Langerhans cells can cross-prime T cells to recognize antigens. Langerhans cells are proposed to stimulate T regulatory cells, and are implicated in the pathogenesis of cutaneous T cell lymphoma.The phenotype of Langerhans cells, which may be tolerogenic or immunogenic, appears to depend on their state of maturity, inciting immunogen and cytokine environment, offering the potential for manipulation in immunotherapy.
Topics: Animals; Antigen Presentation; Cell Movement; Humans; Immune Tolerance; Immunity; Langerhans Cells; Stem Cells
PubMed: 19002380
DOI: 10.1007/s00018-008-8470-y