scholarly journals The role of dendritic cells and their interactions in the pathogenesis of antibody-associated autoimmune encephalitis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Fatme Seval Ismail ◽  
Sven G. Meuth ◽  
Nico Melzer
Keyword(s):  
Dendritic Cells ◽  
Autoimmune Encephalitis ◽  
Brain Parenchyma ◽  
Lymphoid Tissues ◽  
In Vivo Models ◽  
Complex Interactions ◽  
Neuronal Proteins ◽  
Inflammatory Brain Disease ◽  
Therapy Strategies

AbstractAutoimmune encephalitis (AE) is an inflammatory brain disease which is frequently associated with antibodies (Abs) against cell-surface, synaptic or intracellular neuronal proteins. There is increasing evidence that dendritic cells (DCs) are implicated as key modulators in keeping the balance between immune response and tolerance in the CNS. Migratory features of DCs to and from the brain are linked to initiating and maintaining of neuroinflammation. Genetic polymorphisms together with other triggers such as systemic or cerebral viral infection, or systemic malignancies could contribute to the dysbalance of “regulatory” and “encephalitogenic” DCs with subsequent dysregulated T and B cell reactions in AE. Novel in vivo models with implantation of mature DCs containing neuronal antigens could help to study the pathogenesis and perhaps to understand the origin of AE. Investigations of DCs in human blood, lymphoid tissues, CSF, and brain parenchyma of patients with AE are necessary to deepen our knowledge about the complex interactions between DCs, T and B cells during neuroinflammation in AE. This can support developing new therapy strategies.

scholarly journals Vascular Dysfunction Induced by Mercury Exposure

2019 ◽  
Vol 20 (10) ◽  
pp. 2435 ◽  
Author(s):  
Tetsuya Takahashi ◽  
Takayoshi Shimohata
Keyword(s):  
Oxidative Stress ◽  
Vascular Dysfunction ◽  
Brain Parenchyma ◽  
Transport Systems ◽  
Mehg Exposure ◽  
In Vivo Models ◽  
The Central Nervous System ◽  
The Brain

Methylmercury (MeHg) causes severe damage to the central nervous system, and there is increasing evidence of the association between MeHg exposure and vascular dysfunction, hemorrhage, and edema in the brain, but not in other organs of patients with acute MeHg intoxication. These observations suggest that MeHg possibly causes blood–brain barrier (BBB) damage. MeHg penetrates the BBB into the brain parenchyma via active transport systems, mainly the l-type amino acid transporter 1, on endothelial cell membranes. Recently, exposure to mercury has significantly increased. Numerous reports suggest that long-term low-level MeHg exposure can impair endothelial function and increase the risks of cardiovascular disease. The most widely reported mechanism of MeHg toxicity is oxidative stress and related pathways, such as neuroinflammation. BBB dysfunction has been suggested by both in vitro and in vivo models of MeHg intoxication. Therapy targeted at both maintaining the BBB and suppressing oxidative stress may represent a promising therapeutic strategy for MeHg intoxication. This paper reviews studies on the relationship between MeHg exposure and vascular dysfunction, with a special emphasis on the BBB.

scholarly journals Control of Dendritic Cell Migration, T Cell-Dependent Immunity, and Autoimmunity by Protein Tyrosine Phosphatase PTPN12 Expressed in Dendritic Cells

2013 ◽  
Vol 34 (5) ◽  
pp. 888-899 ◽  
Author(s):  
Inmoo Rhee ◽  
Ming-Chao Zhong ◽  
Boris Reizis ◽  
Cheolho Cheong ◽  
André Veillette
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Protein Tyrosine Phosphatase ◽  
Tyrosine Phosphatase ◽  
Genetically Engineered ◽  
Lymphoid Tissues ◽  
Peripheral Tissues ◽  
Protein Tyrosine

Dendritic cells (DCs) capture and process antigens in peripheral tissues, migrate to lymphoid tissues, and present the antigens to T cells. PTPN12, also known as PTP-PEST, is an intracellular protein tyrosine phosphatase (PTP) involved in cell-cell and cell-substratum interactions. Herein, we examined the role of PTPN12 in DCs, using a genetically engineered mouse lacking PTPN12 in DCs. Our data indicated that PTPN12 was not necessary for DC differentiation, DC maturation, or cytokine production in response to inflammatory stimuli. However, it was needed for full induction of T cell-dependent immune responsesin vivo. This function largely correlated with the need of PTPN12 for DC migration from peripheral sites to secondary lymphoid tissues. Loss of PTPN12 in DCs resulted in hyperphosphorylation of the protein tyrosine kinase Pyk2 and its substrate, the adaptor paxillin. Pharmacological inhibition of Pyk2 or downregulation of Pyk2 expression also compromised DC migration, suggesting that Pyk2 deregulation played a pivotal role in the migration defect caused by PTPN12 deficiency. Together, these findings identified PTPN12 as a key regulator in the ability of DCs to induce antigen-induced T cell responses. This is due primarily to the role of PTPN12 in DC migration from peripheral sites to secondary lymphoid organs through regulation of Pyk2.

scholarly journals Minimal modification in the factor VIII B-domain sequence ameliorates the murine hemophilia A phenotype

Blood ◽  
2013 ◽  
Vol 121 (21) ◽  
pp. 4396-4403 ◽  
Author(s):  
Joshua I. Siner ◽  
Nicholas P. Iacobelli ◽  
Denise E. Sabatino ◽  
Lacramiora Ivanciu ◽  
Shangzhen Zhou ◽  
...  
Keyword(s):  
Hemophilia A ◽  
The Novel ◽  
In Vivo Models ◽  
Domain Sequence ◽  
Key Points ◽  
Minimal Modification ◽  
Therapy Strategies ◽  
Enhanced Stability

Key Points The novel FVIII variant (FVIII-RH) has enhanced stability and procoagulant activity in both in vitro and in vivo models. FVIII-RH is efficacious and safe; thus, it is an attractive molecule for protein replacement and as a transgene in gene-therapy strategies.

scholarly journals ITAM signaling in dendritic cells controls T helper cell priming by regulating MHC class II recycling

Blood ◽  
2010 ◽  
Vol 116 (17) ◽  
pp. 3208-3218 ◽  
Author(s):  
Daniel B. Graham ◽  
Holly M. Akilesh ◽  
Grzegorz B. Gmyrek ◽  
Laura Piccio ◽  
Susan Gilfillan ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Mhc Class Ii ◽  
Autoimmune Encephalitis ◽  
Class Ii ◽  
T Helper Cell ◽  
Helper Cell ◽  
Nucleotide Exchange ◽  
T Helper

Abstract Immature dendritic cells (DCs) specialize in antigen capture and maintain a highly dynamic pool of intracellular major histocompatibility complex class II (MHCII) that continuously recycles from peptide loading compartments to the plasma membrane and back again. This process facilitates sampling of environmental antigens for presentation to T helper cells. Here, we show that a signaling pathway mediated by the DC immunoreceptor tyrosine-based activation motif (ITAM)–containing adaptors (DAP12 and FcRγ) and Vav family guanine nucleotide exchange factors controls the half-life of surface peptide-MHCII (pMHCII) complexes and is critical for CD4 T-cell triggering in vitro. Strikingly, mice with disrupted DC ITAMs show defective T helper cell priming in vivo and are protected from experimental autoimmune encephalitis. Mechanistically, we show that deficiency in ITAM signaling results in increased pMHCII internalization, impaired recycling, and an accumulation of ubiquitinated MHCII species that are prematurely degraded in lysosomes. We propose a novel mechanism for control of T helper cell priming.

5-lipoxygenase expression in dendritic cells generated from CD34+ hematopoietic progenitors and in lymphoid organs

Blood ◽  
2000 ◽  
Vol 96 (12) ◽  
pp. 3857-3865
Author(s):  
Rainer Spanbroek ◽  
Markus Hildner ◽  
Dieter Steinhilber ◽  
Norbert Fusenig ◽  
Kozo Yoneda ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Lymphocyte ◽  
Transforming Growth Factor ◽  
Leukotriene B4 ◽  
Lymphoid Tissues ◽  
Ionophore A23187 ◽  
In Cells

The 5-lipoxygenase (5-LO) pathway in human CD34+ hematopoietic progenitor cells, which were induced to differentiate into dendritic cells (DCs) by cytokines in vitro and in DCs of lymphoid tissues in situ, was examined. Extracts prepared from HPCs contained low levels of 5-LO or 5-LO–activating protein. Granulocyte-macrophage colony-stimulating factor (GM-CSF) plus tumor necrosis factor–α (TNF-α) promoted DC differentiation and induced a strong rise in 5-LO and FLAP expression. Fluorescence-activated cell sorter (FACS) analyses identified a major DC population coexpressing human leukocyte antigen (HLA)-DR/CD80 and monocytic or Langerhans cell markers. Transforming growth factor–β1 (TGF-β–1), added to support DC maturation, strongly promoted the appearance of CD1a+/Lag+ Langerhans-type cells as well as mature CD83+ DCs. TGF-β–1 further increased 5-LO and FLAP expression, recruited additional cells into the 5-LO+DC population, and promoted production of 5-hydroxyeicosatetraenoic acid and leukotriene B4 in response to calcium (Ca++) ionophore A23187. These in vitro findings were corroborated by 5-LO expression in distinct DC phenotypes in vivo. Scattered 5-LO and FLAP in situ hybridization signals were recorded in cells of paracortical T-lymphocyte–rich areas and germinal centers (GCs) of lymph nodes (LNs) and tonsil and in cells of mucosae overlying the Waldeyer tonsillar ring. 5-LO protein localized to both CD1a+ immature DCs and to CD83+ mature interdigitating DCs of T-lymphocyte–rich areas of LNs and tonsil. As DCs have the unique ability to initiate naive lymphocyte activation, our data support the hypothesis that leukotrienes act at proximal steps of adaptive immune responses.

scholarly journals Role of Dendritic Cell Targeting in Venezuelan Equine Encephalitis Virus Pathogenesis

2000 ◽  
Vol 74 (2) ◽  
pp. 914-922 ◽  
Author(s):  
Gene H. MacDonald ◽  
Robert E. Johnston
Keyword(s):  
Dendritic Cells ◽  
Lymph Node ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Lymphoid Tissues ◽  
Venezuelan Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Viral Spread ◽  
Draining Lymph Node

ABSTRACT The initial steps of Venezuelan equine encephalitis virus (VEE) spread from inoculation in the skin to the draining lymph node have been characterized. By using green fluorescent protein and immunocytochemistry, dendritic cells in the draining lymph node were determined to be the primary target of VEE infection in the first 48 h following inoculation. VEE viral replicon particles, which can undergo only one round of infection, identified Langerhans cells to be the initial set of cells infected by VEE directly following inoculation. These cells are resident dendritic cells in the skin, which migrate to the draining lymph node following activation. A point mutation in the E2 glycoprotein gene of VEE that renders the virus avirulent and compromises its ability to spread beyond the draining lymph blocked the appearance of virally infected dendritic cells in the lymph node in vivo. A second-site suppressor mutation that restores viral spread to lymphoid tissues and partially restore virulence likewise restored the ability of VEE to infect dendritic cells in vivo.

PARP-1 inhibition prevents CNS migration of dendritic cells during EAE, suppressing the encephalitogenic response and relapse severity

2011 ◽  
Vol 17 (7) ◽  
pp. 794-807 ◽  
Author(s):  
Leonardo Cavone ◽  
Alessandra Aldinucci ◽  
Clara Ballerini ◽  
Tiziana Biagioli ◽  
Flavio Moroni ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Molecular Mechanisms ◽  
Neurological Impairment ◽  
Mouse Bone Marrow ◽  
In Vivo Models ◽  
In Vitro Techniques ◽  
Parp 1

Background: Pharmacological inhibitors of poly(ADP-ribose) polymerase-1 (PARP-1) are currently evaluated in clinical trials for various malignancies but, interestingly, also proved of remarkable efficacy in preclinical models of autoimmune disorders including experimental autoimmune encephalomyelitis (EAE). Objectives: The objectives of the study were to determine molecular mechanisms underlying suppression of the encephalitogenic response by these drugs; likewise, whether clinically-relevant post-treatment paradigms with PARP-1 inhibitors could prevent EAE relapses. Methods: Adopted both in vitro techniques (bone marrow-derived cultured DC) as well as in vivo models of chronic or relapsing–remitting (RR) EAE. Results: We report that two structurally unrelated PARP-1 inhibitors negatively regulated NFκB activation, as well as maturation, cytokine production and APC function of cultured mouse bone marrow-derived dendritic cells (DCs). PARP-1 inhibitors also reduced the number and APC function of DCs migrating in the draining lymph nodes of ovalbumin-immunized mice. In C57Bl mice with chronic EAE or SJL mice with RR EAE, pharmacological inhibition of PARP-1 reduced CNS DC migration and demyelination as well as neurological impairment to an extent similar to that achieved with the potent immunosuppressant cyclosporine A. Remarkably, PARP-1 inhibitors injected after the first phase of disease reduced relapse incidence and severity, as well as the spinal cord number of autoreactive Th17 cells. Under this clinically-relevant treatment paradigm, PARP inhibitors also suppressed epitope spreading of the encephalitogenic response. Conclusions: Overall, data underscore the potential relevance of PARP-1 inhibitors to MS therapy and suppression of autoimmunity.

scholarly journals The Requirement of Membrane Lymphotoxin for the Presence of Dendritic Cells in Lymphoid Tissues

1999 ◽  
Vol 190 (5) ◽  
pp. 629-638 ◽  
Author(s):  
Qiang Wu ◽  
Yang Wang ◽  
Jing Wang ◽  
Elizabeth O. Hedgeman ◽  
Jeffrey L. Browning ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Lymphoid Tissues ◽  
Tnf Receptor ◽  
Wild Type ◽  
Normal Numbers ◽  
And Function ◽  
Necrosis Factor ◽  
Cell Zone

Although several cytokines, including tumor necrosis factor (TNF), can promote the growth of dendritic cells (DCs) in vitro, the cytokines that naturally regulate DC development and function in vivo have not been well defined. Here, we report that membrane lymphotoxin (LT), instead of TNF, regulates the migration of DCs in the spleen. LTα−/− mice, lacking membrane LTα/β and LTα3, show markedly reduced numbers of DCs in the spleen. Unlike wild-type mice and TNF−/− mice that have densely clustered DCs in the T cell zone and around the marginal zone, splenic DCs in LTα−/− mice are randomly distributed. The reduced number of DCs in lymphoid tissues of LTα−/− mice is associated with an increased number of DCs in nonlymphoid tissues. The number of splenic DCs in LTα−/− mice is restored when additional LT-expressing cells are provided. Blocking membrane LTα/β in wild-type mice markedly diminishes the accumulation of DCs in lymphoid tissues. These data suggest that membrane LT is an essential ligand for the presence of DCs in the spleen. Mice deficient in TNF receptor, which is the receptor for both soluble LTα3 and TNF-α3 trimers, have normal numbers of DCs. However, LTβR−/− mice show reduced numbers of DCs, similar to the mice lacking membrane LT α/β. Taken together, these results support the notion that the signaling via LTβR by membrane LTα/β is required for the presence of DCs in lymphoid tissues.

scholarly journals MHC class II–restricted antigen presentation by plasmacytoid dendritic cells inhibits T cell–mediated autoimmunity

2010 ◽  
Vol 207 (9) ◽  
pp. 1891-1905 ◽  
Author(s):  
Magali Irla ◽  
Natalia Küpfer ◽  
Tobias Suter ◽  
Rami Lissilaa ◽  
Mahdia Benkhoucha ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Plasmacytoid Dendritic Cells ◽  
T Cell Response ◽  
Lymphoid Tissues ◽  
Capture Process

Although plasmacytoid dendritic cells (pDCs) express major histocompatibility complex class II (MHCII) molecules, and can capture, process, and present antigens (Ags), direct demonstrations that they function as professional Ag-presenting cells (APCs) in vivo during ongoing immune responses remain lacking. We demonstrate that mice exhibiting a selective abrogation of MHCII expression by pDCs develop exacerbated experimental autoimmune encephalomyelitis (EAE) as a consequence of enhanced priming of encephalitogenic CD4+ T cell responses in secondary lymphoid tissues. After EAE induction, pDCs are recruited to lymph nodes and establish MHCII-dependent myelin-Ag–specific contacts with CD4+ T cells. These interactions promote the selective expansion of myelin-Ag–specific natural regulatory T cells that dampen the autoimmune T cell response. pDCs thus function as APCs during the course of EAE and confer a natural protection against autoimmune disease development that is mediated directly by their ability to present of Ags to CD4+ T cells in vivo.

scholarly journals Differential Uptake and Processing of a Haemophilus influenzae P5-Derived Immunogen by Chinchilla Dendritic Cells

2007 ◽  
Vol 76 (3) ◽  
pp. 967-977 ◽  
Author(s):  
Laura A. Novotny ◽  
Santiago Partida-Sánchez ◽  
Robert S. Munson ◽  
Lauren O. Bakaletz
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Haemophilus Influenzae ◽  
Protective Immunity ◽  
Lymphoid Tissues ◽  
Lymphoid Aggregate ◽  
Intranasal Immunization ◽  
Bone Marrow Precursor

ABSTRACT Dendritic cells (DCs) are potent antigen-presenting cells involved in the initiation and modulation of immune responses after immunization via their ability to process and present antigen to naive T cells. We wanted to examine the role of DCs in the development of protective immunity against nontypeable Haemophilus influenzae (NTHI)-induced experimental otitis media (OM) after intranasal immunization of chinchillas with an NTHI P5-derived synthetic peptide immunogen called LB1. As chinchilla DCs have not been described, we adapted well-established protocols to induce the differentiation of chinchilla bone marrow precursor cells into DCs, which resulted in cells that were morphologically and phenotypically similar to DCs of other species. In vitro, chinchilla DCs readily internalized LB1, upregulated expression of the maturation markers CD80 and major histocompatibility complex class II, and presented processed LB1 to primed CD3+ T cells, which resulted in antigen-specific T-cell proliferation. In vivo, LB1-activated DCs trafficked from the chinchilla nasal cavity primarily to the nasal-associated lymphoid tissues and were detected in close proximity to CD3+ T cells within this lymphoid aggregate. These data are the first to characterize chinchilla DCs and their functional properties. Furthermore, they suggest an important role for chinchilla DCs in the development of protective immunity against experimental NTHI-induced OM after intranasal immunization.

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