The blood-brain barrier (BBB) serves as a highly intricate and dynamic interface connecting the brain and the bloodstream, playing a vital role in maintaining brain homeostasis. BBB dysfunction has ...been associated with multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS); however, the role of the BBB in neurodegeneration is understudied. We developed an ALS patient-derived model of the BBB by using cells derived from 5 patient donors carrying C9ORF72 mutations. Brain microvascular endothelial-like cells (BMEC-like cells) derived from C9ORF72-ALS patients showed altered gene expression, compromised barrier integrity, and increased P-glycoprotein transporter activity. In addition, mitochondrial metabolic tests demonstrated that C9ORF72-ALS BMECs display a significant decrease in basal glycolysis accompanied by increased basal and ATP-linked respiration. Moreover, our study reveals that C9-ALS derived astrocytes can further affect BMECs function and affect the expression of the glucose transporter Glut-1. Finally, C9ORF72 patient-derived BMECs form leaky barriers through a cell-autonomous mechanism and have neurotoxic properties towards motor neurons.
An efficient strategy for programming dendritic cells (DCs) for cancer immunotherapy is the optimization of their maturation so that they can efficiently stimulate cancer-specific T cell responses. ...Interleukin (IL)-4 has appeared as an essential cytokine, widely used in vitro with granulocyte macrophage-colony stimulating factor (GM-CSF) to differentiate monocytes into immature DCs (iDC) and to prevent macrophage formation. Conflicting data have been published regarding the effect of IL-4 on functional DC maturation. To further understand IL-4's effects on DC maturation and function in vitro, we choose the most commonly used maturation factor tumor necrosis factor (TNF)-α.
Human monocyte-derived iDC were treated for 48 h with GM-CSF and TNF-α in the presence (IL-4(+)-DC) or absence (IL-4(-)-DC) of IL-4 and functions of both DC populations were compared.
On mixed lymphocyte reaction assay, IL-4(+)-DC were less potent than IL-4(-)-DC at inducing the proliferation of allogeneic CD4(+) T cells and the proportion of activated T cells expressing CD69 and/or CD25 was smaller. Interleukin-4 reduced the cell-surface expression of TNF-α-induced DC maturation markers CD83, CD86, HLA-DR and CD25 and generated a heterogeneous population of DCs. IL-4(+)-DC secreted less IL-12 and more IL-10 than IL-4(-)-DC following activation by soluble CD40L, and IL-4(+)-DC-activated T cells secreted lesser amounts of T helper (Th) 1 cytokines (IL-2 and interferon-γ). Importantly, IL-4 impaired the in vitro migratory capacity of DCs in response to CCL21 and CCL19 chemokines. This effect was related to reduced expression of CCR7 at both mRNA and protein levels.
Interleukin-4 used with GM-CSF and TNF-α during the maturation of DCs in vitro impaired DC functions and disturbed the maturation effect of TNF-α. Finally, our study reinforces the view that the quality of the DC maturation stimulus, which regulates DC migration and cytokine production, may be a decisive feature of the immunogenicity of DCs.
Dendritic cells (DCs) play a key role in immunity and are highly potent at presenting antigens and orienting the immune response. Depending on the environmental signals, DCs could turn the immune ...response toward immunity or immune tolerance. Several subsets of DCs have been described, with each expressing various surface receptors and all participating in DC-associated immune functions according to their specific skills. DC subsets could also contribute to the vicious circle of inflammation in immune diseases and establishment of immune tolerance in cancer. They appear to be appropriate targets in the control of inflammatory diseases or regulation of autoimmune responses. For all these reasons, in situ DC targeting with therapeutic antibodies seems to be a suitable way of modulating the entire immune system. At present, the field of antibody-based therapies has mainly been developed in oncology, but it is undergoing remarkable expansion thanks to a wide variety of antibody formats and their related functions. Moreover, current knowledge of DC biology may open new avenues for targeting and modulating the different DC subsets. Based on an update of pathogen recognition receptor expression profiles in human DC subsets, this review evaluates the possibility of inducing tolerant DCs using antibody-based therapeutic agents.
Amyotrophic lateral sclerosis (ALS) is a degenerative disease that progressively destroys motor neurons (MNs). Earlier studies identified EphA4, a receptor tyrosine kinase, as a possible ...disease-modifying gene. The complex interplay between the EphA4 receptor and its ephrin ligands in motor neurons and astrocytes has not yet been fully elucidated and includes a putative pro-apoptotic activity of the unbound receptor compared to ephrin-bound receptor. We recently reported that astrocytes from patients with ALS induce cell death in co-cultured MNs. Here we found that first-generation synthetic EphA4 agonistic agent 123C4, effectively protected MNs when co-cultured with reactive astrocytes from patients with ALS from multiple subgroups (sALS and mutant SOD1). Newer generation and more potent EphA4 agonistic agents 150D4, 150E8, and 150E7 provided effective protection at a lower therapeutic dose. Combined, the data suggest that the development of EphA4 agonistic agents provides potentially a promising therapeutic strategy for patients with ALS.
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•We report on potent and selective EphA4 agents targeting its ligand-binding domain•We used a method that generates neuronal progenitor cells from patient fibroblasts•The agents reverse motor neuron cell death are cellular models of patients with ALS•Our EphA4 agonists can effectively prevent astrocyte-mediated motor neuron toxicity
Medical biochemistry; Molecular biology; Neuroscience
There is an urgent need for alternative therapies targeting human dendritic cells (DCs) that could reverse inflammatory syndromes in many autoimmune and inflammatory diseases and organ ...transplantations. Here, we describe a bispecific antibody (bsAb) strategy tethering two pathogen-recognition receptors at the surface of human DCs. This cross-linking switches DCs into a tolerant profile able to induce regulatory T-cell differentiation. The bsAbs, not parental Abs, induced interleukin 10 and transforming growth factor β1 secretion in monocyte-derived DCs and human peripheral blood mononuclear cells. In addition, they induced interleukin 10 secretion by synovial fluid cells in rheumatoid arthritis and gout patients. This concept of bsAb-induced tethering of surface pathogen-recognition receptors switching cell properties opens a new therapeutic avenue for controlling inflammation and restoring immune tolerance.
Commensal gut bacteria are essential for the development and maintenance of the gut's immune system. Some bacteria strains, such as
Lactobacillus and
Bifidobacterium species, have been reported to ...provide protection from allergic and inflammatory bowel diseases. However, the interactions between these commensal bacteria and the immune system are largely unknown.
We studied the effects of a supernatant from the culture of
B breve C50 (BbC50) on the maturation, activation, and survival of human dendritic cells (DCs).
DCs were differentiated from human monocytes with IL-4 and GM-CSF for 5 days and cultured with BbC50 supernatant (BbC50
SN) or LPS for 2 days.
BbC50
SN induced DC maturation, with increase in CD83, CD86, and HLA-DR expression. We also showed, for the first time, that BbC50
SN prolonged DC survival, with high IL-10 and low IL-12 production compared with that seen in LPS-DCs. Moreover, BbC50
SN inhibited the effects of LPS on DCs, both in terms of IL-12 production and in terms of survival. The prolonged DC survival was independent of IL-10 production and nuclear factor κB pathway but was associated with an upregulation of Bcl-x
L and Phospho-Bad. Finally, BbC50
SN induced activation of Toll-like receptor 2 (TLR2)–transfected cells in contrast to TLR4-, TLR7-, and TLR9-transfected cells.
The supernatant of
B breve C50 can induce DC maturation and prolonged DC survival through TLR2, with high IL-10 production. These properties might correspond to a regulatory DC profile, which could limit the excessive T
H1 response and control the excessive T
H2 polarization observed in atopic newborns.
Regulatory T cells (Treg) play a crucial role in controlling immunity and transplant rejection. Two main groups of Treg have been described: antigen-induced Treg (iTreg) and natural Treg (nTreg). The ...ways to induce and the mechanisms of action of Treg subsets remained ill defined, particularly for their effects on CD8(+) T cells. CD8(+) T cells are major agents in the rejection of allografts; the aim of this study is to investigate the effects exerted on CD8(+) T cells by human CD4(+) iTreg induced by mycophenolic acid-treated dendritic cells. iTreg suppress the proliferation of CD8(+) T cells by allogeneic cell-cell interaction with mature dendritic cells and irrespectively of the TCR specificity of the CD8(+) T cells and cell-cell contact of iTreg with CD8(+) T cells. In our model, this suppression is independent of the action of IL-10 and TGF-β1. iTreg were able to modify phenotype and inhibited IFN-γ and TNF-α secretion by CD8(+) T cells. Most interestingly, iTreg inhibit the synthesis of perforin and of granzymes A and B by CD8(+) T cells and impaired their cytotoxicity against allogeneic targets. In summary, our study showed the involvement of iTreg in the down-regulation of cytotoxic responses mediated by CD8(+) T cells in an allospecific context. Following studies that have shown the existence of a regulation control exerted by iTreg on CD4(+) T cells and dendritic cells, this work ultimately shows that this regulation can reach CD8(+) T-cell functions.
Tocilizumab, a humanized anti-IL-6 receptor α (IL-6Rα) is widely used in the treatment of a panel of pathologies such as adult and juvenile rheumatoid arthritis (RA) and the systemic form of juvenile ...idiopathic arthritis in children. Its indications are expected to be largely extended to other inflammatory diseases in close future. Dendritic cells (DCs) appear to be deeply involved in the immunopathology of these diseases, yet the effects of tocilizumab on these cells were poorly studied. In this study, we explored the effect of tocilizumab on the regulation of IL-6R subunits gp130, soluble form of IL-6Rα (sIL-6Rα), and mIL-6Rα in human monocyte-derived DCs. Human DCs were derived from CD14
monocytes purified with beads with IL-4 and granulocyte macrophage colony-stimulating factor.
cultures of DCs were performed in the presence of tocilizumab. Using lipopolysaccharide (LPS) maturation of DCs, we demonstrated that tocilizumab did not inhibit IL-6 secretion, enhanced mIL-6Rα expression, and largely increased sIL-6Rα secretion. MAPK modulated STAT3 phosphorylation and surface expression of IL-6Rα in LPS-DCs. Tocilizumab had no impact on STAT3 phosphorylation in LPS-DCs while both LPS and IL-6 increased its activation. Tocilizumab modulated the regulation of IL-6R subunits leading to an inflammatory status of DCs and a massive secretion of IL-6Rα. Our results demonstrate that DCs acquire a pro-inflammatory profile following tocilizumab treatment, becoming a major source of IL-6
-signaling activation that might explain the poor clinical benefit in some RA patients.
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