Search results for "Dendritic cell"
showing 10 items of 447 documents
Immunomodulatory activity of microRNAs: potential implications for multiple myeloma treatment
2015
Multiple myeloma (MM) is an incurable plasma cell neoplasm accounting for about 10% of all hematologic malignancies. Recently, emerging evidence is disclosing the complexity of bone marrow interactions between MM cells and infiltrating immune cells, which have been reported to promote proliferation, survival and drug resistance of tumor cells. MicroRNAs (miRNAs) are small non-coding RNA molecules with regulatory functions in the cell, whose expression has predictive and prognostic value in different malignancies. MiRNAs are gaining increasing interest due to their capability to polarize the immune-response through different mechanisms, which include the molecular reprogramming of immune cel…
Epithelium‐specific MyD88 signaling, but not DCs or macrophages, control acute intestinal infection with Clostridium difficile
2019
Infection with Clostridium difficile is one of the major causes of health care acquired diarrhea and colitis. Signaling though MyD88 downstream of TLRs is critical for initiating the early protective host response in mouse models of C. difficile infection (CDI). In the intestine, MyD88 is expressed in various tissues and cell types, such as the intestinal epithelium and mononuclear phagocytes (MNP), including DC or macrophages. Using a genetic gain-of-function system, we demonstrate here that restricting functional MyD88 signaling to the intestinal epithelium, but also to MNPs is sufficient to protect mice during acute CDI by upregulation of the intestinal barrier function and recruitment o…
Tnfaip3 expression in pulmonary conventional type 1 Langerin‐expressing dendritic cells regulates T helper 2‐mediated airway inflammation in mice
2020
Abstract Background Conventional type 1 dendritic cells (cDC1s) control anti‐viral and anti‐tumor immunity by inducing antigen‐specific cytotoxic CD8+ T‐cell responses. Controversy exists whether cDC1s also control CD4+ T helper 2 (Th2) cell responses, since suppressive and activating roles have been reported. DC activation status, controlled by the transcription factor NF‐κB, might determine the precise outcome of Th‐cell differentiation upon encounter with cDC1s. To investigate the role of activated cDC1s in Th2‐driven immune responses, pulmonary cDC1s were activated by targeted deletion of A20/Tnfaip3, a negative regulator of NF‐κB signaling. Methods To target pulmonary cDC1s, Cd207 (Lan…
E-Cadherin is Dispensable to Maintain Langerhans Cells in the Epidermis.
2019
The cell adhesion molecule E-cadherin is a major component of adherens junctions and marks Langerhans cells (LC), the only dendritic cell (DC) population of the epidermis. LC form a dense network and attach themselves to the surrounding keratinocytes via homophilic E-cadherin binding. LC activation, mobilization, and migration require a reduction in LC E-cadherin expression. To determine whether E-cadherin plays a role in regulating LC homeostasis and function, we generated CD11c-specific E-cadherin knockout mice (CD11c-Ecaddel). In the absence of E-cadherin−mediated cell adhesion, LC numbers remained stable and similar as in control mice, even in aged animals. Intriguingly, E-cadherin−defi…
FLT3 Ligand as a Molecular Adjuvant for Naked RNA Vaccines
2016
Intranodal immunization with antigen-encoding naked mRNA has proven to be an efficacious and safe approach to induce antitumor immunity. Thanks to its unique characteristics, mRNA can act not only as a source for antigen but also as an adjuvant for activation of the immune system. The search for additional adjuvants that can be combined with mRNA to further improve the potency of the immunization revealed Fms-like tyrosine kinase 3 (FLT3) ligand as a potent candidate. Systemic administration of the dendritic cell-activating FLT3 ligand prior to or along with mRNA immunization-enhanced priming and expansion of antigen-specific CD8(+) T cells in lymphoid organs, T-cell homing into melanoma tu…
IL-10-Modulated Human Dendritic Cells for Clinical Use: Identification of a Stable and Migratory Subset with Improved Tolerogenic Activity.
2015
Abstract Dendritic cells (DCs) are key regulators of protective immune responses and tolerance to (self-)Ags. Therefore, the scientific rationale for the use of tolerogenic DC therapy in the fields of allergies, autoimmunity, and transplantation medicine is strong. In this study, we analyzed the tolerogenic capacity of IL-10–modulated DC (IL-10DC) subpopulations to identify a DC subset that combines potent immunosuppressive activities with valuable immune properties for clinical implementation. IL-10DCs consist of two phenotypically distinct subpopulations: CD83highCCR7+ IL-10DCs and CD83lowCCR7− IL-10DCs. Suppressor assays with activated effector T cells revealed that CD4+ regulatory T cel…
Dendritic cells tip the balance towards induction of regulatory T cells upon priming in experimental autoimmune encephalomyelitis
2016
Counter-balancing regulatory mechanisms, such as the induction of regulatory T cells (Treg), limit the effects of autoimmune attack in neuroinflammation. However, the role of dendritic cells (DCs) as the most powerful antigen-presenting cells, which are intriguing therapeutic targets in this context, is not fully understood. Here, we demonstrate that conditional ablation of DCs during the priming phase of myelin-specific T cells in experimental autoimmune encephalomyelitis (EAE) selectively aborts inducible Treg (iTreg) induction, whereas generation of T helper (Th)1/17 cells is unaltered. DCs facilitate iTreg induction by creating a milieu with high levels of interleukin (IL)-2 due to a st…
Gatekeeper role of brain antigen‐presenting CD11c + cells in neuroinflammation
2015
Multiple sclerosis is the most frequent chronic inflammatory disease of the CNS. The entry and survival of pathogenic T cells in the CNS are crucial for the initiation and persistence of autoimmune neuroinflammation. In this respect, contradictory evidence exists on the role of the most potent type of antigen-presenting cells, dendritic cells. Applying intravital two-photon microscopy, we demonstrate the gatekeeper function of CNS professional antigen-presenting CD11c(+) cells, which preferentially interact with Th17 cells. IL-17 expression correlates with expression of GM-CSF by T cells and with accumulation of CNS CD11c(+) cells. These CD11c(+) cells are organized in perivascular clusters…
TGF-β inhibitor Smad7 regulates dendritic cell-induced autoimmunity
2017
TGF-β is an anti-inflammatory cytokine whose signaling is negatively controlled by Smad7. Previously, we established a role for Smad7 in the generation of autoreactive T cells; however, the function of Smad7 in dendritic cells (DCs) remains elusive. Here, we demonstrate that DC-specific Smad7 deficiency resulted in elevated expression of the transcription factors Batf3 and IRF8, leading to increased frequencies of CD8(+)CD103(+) DCs in the spleen. Furthermore, Smad7-deficient DCs expressed higher levels of indoleamine 2,3-dioxygenase (IDO), an enzyme associated with tolerance induction. Mice devoid of Smad7 specifically in DCs are resistant to the development of experimental autoimmune ence…
Gradual development of psoriatic skin lesions by constitutive low-level expression of IL-17A
2016
Psoriasis is a common chronic inflammatory skin disease restricted to humans. The understanding of its pathogenesis has long been hampered by the lack of suitable chronic mouse models. The cytokine IL-17A has emerged as a key player in epithelial immune responses and the defense against extracellular pathogens. Moreover, enhanced expression of IL-17A can turn pathologic and is closely associated with psoriasis. In this study, we generated a novel transgenic mouse model that recapitulates many characteristics of psoriasis. DC-1L-17A(ind) mice with constitutive low-level expression of IL-17A by CD11c(+) cells gradually develop skin lesions during adult life. The lesions preferentially occur a…