Crystal Structure of the Extracellular Domain of the Human Dendritic Cell Surface Marker CD83

Comparison of immunoexpression of dendritic cells, mast cells and blood vessels in periodontal disease between adults and elderly

OBJECTIVE

The aim of this study was to compare, in adults and elderly individuals, the immunoexpression of immature and mature dendritic cells (DCs), mast cells, and blood vessels in healthy and diseased gingival tissues.

MATERIALS AND METHODS

The expressions of immunohistochemical markers, including CD1a (immature dendritic cells), CD83 (mature dendritic cells), tryptase (mast cells) and CD34 (blood vessels), were analyzed in gingival biopsies from elderly (n = 27) and adult (n = 127) patients presenting health, gingivitis and periodontitis. Positive cells for each specimen and marker were counted.

RESULTS

There were no differences in the immunostaining of DCs, mast cells and the amount of blood vessels among gingival biopsies with health, gingivitis and periodontitis in adult and elderly subjects (p > 0.05). Immature DCs were more frequent in tissues with gingivitis and periodontitis in elderly patients, when compared to adults (p < 0.05). Furthermore, degranulated mast cell counts were higher, whereas the number of microvessels was lower in gingivitis in the elderly, when compared to adults (p < 0.05).

CONCLUSIONS

Diseased periodontal sites in the elderly present an overall significant overexpression of immature DCs and degranulated mast cells, in relation to those of adults. Furthermore, gingivitis in elderly is associated with decreased microvessel growth. These immunoinflammatory differences between elderly and adults may have implications in periodontal tissue breakdown in the late adulthood. Further studies should be performed to elucidate this hypothesis.

CLINICAL RELEVANCE

Understading the relationship between aging and changes in immune cells during periodontal inflammation may lead to therapeutic targets for the future management of periodontal diseases.

Exploration of Key Immune-Related Transcriptomes Associated with Doxorubicin-Induced Cardiotoxicity in Patients with Breast Cancer

Based on a few studies, heart failure patients with breast cancer were assessed to find potential biomarkers for doxorubicin-induced cardiotoxicity. However, key immune-related transcriptional markers linked to doxorubicin-induced cardiotoxicity in breast cancer patients have not been thoroughly investigated. We used GSE40447, GSE76314, and TCGA BRCA cohorts to perform this study. Then, we performed various bioinformatics approaches to identify the key immune-related transcriptional markers and their association with doxorubicin-induced cardiotoxicity in patients with breast cancer. We found 255 upregulated genes and 286 downregulated genes in patients with doxorubicin-induced heart failure in breast cancer. We discovered that in patients with breast cancer comorbidity doxorubicin-induced cardiotoxicity, the 58 immunological genes are elevated (such as CPA3, VSIG4, GATA2, RFX2, IL3RA, and LRP1), and the 60 genes are significantly suppressed (such as MS4A1, FCRL1, CD200, FCRLA, FCRL2, and CD79A). Furthermore, we revealed that the immune-related differentially expressed genes (DEGs) are substantially associated with the enrichment of KEGG pathways, including B-cell receptor signaling pathway, primary immunodeficiency, chemokine signaling pathway, hematopoietic cell lineage, cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, MAPK signaling pathway, focal adhesion, dilated cardiomyopathy, cell adhesion molecule, etc. Moreover, we discovered that the doxorubicin-induced immune-related genes are crucially involved in the protein-protein interaction and gene clusters. The immune-related genes, including IFIT5, XCL1, SPIB, BTLA, MS4A1, CD19, TCL1A, CD83, CD200, FCRLA, CD79A, BIRC3, and IGF2R are significantly associated with a poor survival prognosis of breast cancer patients and showed diagnostic efficacy in patients with breast cancer and heart failure. Molecular docking revealed that the survival-associated genes interact with the doxorubicin with appreciable binding affinity. Finally, we validated the expression level of immune-related genes in breast cancer patients-derived cardiomyocytes with doxorubicin-induced cardiotoxicity and found that the level of RAD9A, HSPA1B, GATA2, IGF2R, CD200, ERCC8, and BCL11A genes are consistently dysregulated. Our findings offered a basis for understanding the mechanism and pathogenesis of the cardiotoxicity caused by doxorubicin in breast cancer patients and predicted the interaction of immune-related potential biomarkers with doxorubicin.

CD83 Regulates the Immune Responses in Inflammatory Disorders

Activating the immune system plays an important role in maintaining physiological homeostasis and defending the body against harmful infections. However, abnormalities in the immune response can lead to various immunopathological responses and severe inflammation. The activation of dendritic cells (DCs) can influence immunological responses by promoting the differentiation of T cells into various functional subtypes crucial for the eradication of pathogens. CD83 is a molecule known to be expressed on mature DCs, activated B cells, and T cells. Two isotypes of CD83, a membrane-bound form and a soluble form, are subjects of extensive scientific research. It has been suggested that CD83 is not only a ubiquitous co-stimulatory molecule but also a crucial player in monitoring and resolving inflammatory reactions. Although CD83 has been involved in immunological responses, its functions in autoimmune diseases and effects on pathogen immune evasion remain unclear. Herein, we outline current immunological findings and the proposed function of CD83 in inflammatory disorders.

The CD83 Molecule - An Important Immune Checkpoint

The CD83 molecule has been identified to be expressed on numerous activated immune cells, including B and T lymphocytes, monocytes, dendritic cells, microglia, and neutrophils. Both isoforms of CD83, the membrane-bound as well as its soluble form are topic of intensive research investigations. Several studies revealed that CD83 is not a typical co-stimulatory molecule, but rather plays a critical role in controlling and resolving immune responses. Moreover, CD83 is an essential factor during the differentiation of T and B lymphocytes, and the development and maintenance of tolerance. The identification of its interaction partners as well as signaling pathways have been an enigma for the last decades. Here, we report the latest data on the expression, structure, and the signaling partners of CD83. In addition, we review the regulatory functions of CD83, including its striking modulatory potential to maintain the balance between tolerance versus inflammation during homeostasis or pathologies. These immunomodulatory properties of CD83 emphasize its exceptional therapeutic potential, which has been documented in specific preclinical disease models.

CD83: Activation Marker for Antigen Presenting Cells and Its Therapeutic Potential

CD83 is a member of the immunoglobulin (Ig) superfamily and is expressed in membrane bound or soluble forms. Membrane CD83 (mCD83) can be detected on a variety of activated immune cells, although it is most highly and stably expressed by mature dendritic cells (DC). mCD83 regulates maturation, activation and homeostasis. Soluble CD83 (sCD83), which is elevated in the serum of patients with autoimmune disease and some hematological malignancies is reported to have an immune suppressive function. While CD83 is emerging as a promising immune modulator with therapeutic potential, some important aspects such as its ligand/s, intracellular signaling pathways and modulators of its expression are unclear. In this review we discuss the recent biological findings and the potential clinical value of CD83 based therapeutics in various conditions including autoimmune disease, graft-vs.-host disease, transplantation and hematological malignancies.

Soluble CD83 Alleviates Experimental Autoimmune Uveitis by Inhibiting Filamentous Actin-Dependent Calcium Release in Dendritic Cells

Soluble CD83 (sCD83) is the extracellular domain of the membrane-bound CD83 molecule, and known for its immunoregulatory functions. Whether and how sCD83 participates in the pathogenesis of uveitis, a serious inflammatory disease of the eye that can cause visual disability and blindness, is unknown. By flow cytometry and imaging studies, we show that sCD83 alleviates experimental autoimmune uveitis (EAU) through a novel mechanism. During onset and recovery of EAU, the level of sCD83 rises in the serum and aqueous humor, and CD83⁺ leukocytes infiltrate the inflamed eye. Systemic or topical application of sCD83 exerts a protective effect by decreasing inflammatory cytokine expression, reducing ocular and splenic leukocyte including CD4⁺ T cells and dendritic cells (DCs). Mechanistically, sCD83 induces tolerogenic DCs by decreasing the synaptic expression of co-stimulatory molecules and hampering the calcium response in DCs. These changes are caused by a disruption of the cytoskeletal rearrangements at the DC–T cell contact zone, leading to altered localization of calcium microdomains and suppressed T-cell activation. Thus, the ability of sCD83 to modulate DC-mediated inflammation in the eye could be harnessed to develop new immunosuppressive therapeutics for autoimmune uveitis.

NK cells are negatively regulated by sCD83 in experimental autoimmune uveitis

Natural killer (NK) cells represent a subset of lymphocytes that contribute to innate immunity and have been reported to play a role in autoimmune uveitis. However, the mechanisms regulating NK cellular function in this condition remain unclear. Herein, we investigated the status of NK cells in experimental autoimmune uveitis (EAU). We found that the number of CD83+CD3-NK1.1+ cells was increased in the inflamed eyes and spleens of the EAU mouse model. At the recovery stage of EAU, serum concentrations of soluble CD83 (sCD83) were increased. sCD83 treatment relieved retinal tissue damage and decreased the number of infiltrating NK cells in inflamed eyes. Further analysis of the effects of sCD83 treatment in EAU revealed that it reduced: 1) the expressions of CD11b and CD83 in NK cells, 2) the percent of CD11bhighCD27lowCD3-NK1.1+ cells and 3) the secretion of granzyme B, perforin and IFN-γ in NK cells as demonstrated both in vivo and in vitro. When sCD83 treated-NK cells were transferred into EAU mice, retinal tissue damage was relieved. These results demonstrate sCD83 down-regulate NK cellular function and thus provide important, new information regarding the means for the beneficial effects of this agent in the treatment of autoimmune uveitis.