CD4+FOXP3+ Tregs are currently explored to develop cell therapies against immune‐mediated disorders, with an increasing focus on antigen receptor‐engineered Tregs. Deciphering their mode of action is ...necessary to identify the strengths and limits of this approach. Here, we addressed this issue in an autoimmune disease of the CNS, EAE. Following disease induction, autoreactive Tregs upregulated LAG‐3 and CTLA‐4 in LNs, while IL‐10 and amphiregulin (AREG) were increased in CNS Tregs. Using genetic approaches, we demonstrated that IL‐10, CTLA‐4, and LAG‐3 were nonredundantly required for the protective function of antigen receptor‐engineered Tregs against EAE in cell therapy whereas AREG was dispensable. Treg‐derived IL‐10 and CTLA‐4 were both required to suppress acute autoreactive CD4+ T‐cell activation, which correlated with disease control. These molecules also affected the accumulation in the recipients of engineered Tregs themselves, underlying complex roles for these molecules. Noteworthy, despite the persistence of the transferred Tregs and their protective effect, autoreactive T cells eventually accumulated in the spleen of treated mice. In conclusion, this study highlights the remarkable power of antigen receptor‐engineered Tregs to appropriately provide multiple suppressive factors nonredundantly necessary to prevent autoimmune attacks.
Graphical : Autoreactive Tregs produced by gene therapy are a promising approach for cell therapy of immunological diseases. We found that IL‐10, CTLA‐4, and LAG‐3 were nonredundantly involved in their protective effect in EAE, underlining their unique capacity to appropriately deliver in time and space crucial nonredundant mechanisms of immune regulation.
Excessive inflammation occurs during infection and autoimmunity in mice lacking the alpha-subunit of the interleukin 27 (IL-27) receptor. The molecular mechanisms underlying this increased ...inflammation are incompletely understood. Here we report that IL-27 upregulated IL-10 in effector T cells that produced interferon-gamma and expressed the transcription factor T-bet but did not express the transcription factor Foxp3. These IFN-gamma+T-bet+Foxp3- cells resembled effector T cells that have been identified as the main source of host-protective IL-10 during inflammation. IL-27-induced production of IL-10 was associated with less secretion of IL-17, and exogenous IL-27 reduced the severity of adoptively transferred experimental autoimmune encephalomyelitis by a mechanism dependent on IL-10. Our data show that IL-27-induced production of IL-10 by effector T cells contributes to the immunomodulatory function of IL-27.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Numerous studies have demonstrated the role of immune cells, in particular macrophages, in central nervous system (CNS) pathologies. There are two main macrophage populations in the CNS: (i) the ...microglia, which are the resident macrophages of the CNS and are derived from yolk sac progenitors during embryogenesis, and (ii) the monocyte-derived macrophages (MDM), which can infiltrate the CNS during disease and are derived from bone marrow progenitors. The roles of each macrophage subpopulation differ depending on the pathology being studied. Furthermore, there is no consensus on the histological markers or the distinguishing criteria used for these macrophage subpopulations. However, the analysis of the expression profiles of the CD11b and CD45 markers by flow cytometry allows us to distinguish the microglia (CD11b
CD45
) from the MDM (CD11b
CD45
). In this protocol, we show that the density gradient centrifugation and the flow cytometry analysis can be used to characterize these CNS macrophage subpopulations, and to study several markers of interest expressed by these cells as we recently published. Thus, this technique can further our understanding of the role of macrophages in mouse models of neurological diseases and can also be used to evaluate drug effects on these cells.
Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are autoimmune demyelinating diseases of the central nervous system (CNS). Interferon-γ-producing Th1 ...and interleukin-17-producing Th17 CD4
+
T helper (Th) cells mediate disease pathogenesis in EAE and likely in MS as well. However, the relative contribution of each Th subset to autoimmune processes in the CNS remains unclear. Emerging data suggest that both Th1 and Th17 cells contribute to CNS autoimmunity, albeit through different mechanisms. A better understanding of the roles that Th1 and Th17 cells play in autoimmune inflammation will be helpful in developing new therapeutic approaches. In this review, we discuss recent findings on the roles of Th1 and Th17 cells in the pathogenesis of EAE.
Neisseria meningitidis (the meningococcus) remains a major cause of bacterial meningitis and fatal sepsis. This commensal bacterium of the human nasopharynx can cause invasive diseases when it leaves ...its niche and reaches the bloodstream. Blood-borne meningococci have the ability to adhere to human endothelial cells and rapidly colonize microvessels. This crucial step enables dissemination into tissues and promotes deregulated inflammation and coagulation, leading to extensive necrotic purpura in the most severe cases. Adhesion to blood vessels relies on type IV pili (TFP). These long filamentous structures are highly dynamic as they can rapidly elongate and retract by the antagonistic action of two ATPases, PilF and PilT. However, the consequences of TFP dynamics on the pathophysiology and the outcome of meningococcal sepsis in vivo have been poorly studied. Here, we show that human graft microvessels are replicative niches for meningococci, that seed the bloodstream and promote sustained bacteremia and lethality in a humanized mouse model. Intriguingly, although pilus-retraction deficient N. meningitidis strain (ΔpilT) efficiently colonizes human graft tissue, this mutant did not promote sustained bacteremia nor induce mouse lethality. This effect was not due to a decreased inflammatory response, nor defects in bacterial clearance by the innate immune system. Rather, TFP-retraction was necessary to promote the release of TFP-dependent contacts between bacteria and, in turn, the detachment from colonized microvessels. The resulting sustained bacteremia was directly correlated with lethality. Altogether, these results demonstrate that pilus retraction plays a key role in the occurrence and outcome of meningococcal sepsis by supporting sustained bacteremia. These findings open new perspectives on the role of circulating bacteria in the pathological alterations leading to lethal sepsis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IL‐17‐secreting CD8+ T cells (Tc17 cells) have been implicated in immunity to infections, cancer, and autoimmune diseases. Thus far, studies on Tc17 cells have primarily investigated their ...development from naïve precursors, while the biology of committed Tc17 cells has been less characterized, in particular during the effector phase of immune responses. IL‐27 is an important regulator of inflammation through the induction of regulatory Tr1 cells, as well as a suppressor of Th17‐cell development. IL‐27 suppresses the development of Tc17 cells, but its effects on committed Tc17 cells are unknown. Here we demonstrate that even though IL‐27 completely inhibited the development of C57BL/6 mouse Tc17 cells, it had little effect on previously committed Tc17 cells. Although committed Tc17 cells were capable of responding to IL‐27, it had no effect on expression of RORγt and RORα, or production of various cytokines. Committed Tc17 cells did not express granzyme B and lacked cytotoxicity in vitro, features that remained unaltered by IL‐27 treatment. Nonetheless, they efficiently induced diabetes, irrespective of treatment with IL‐27 prior to transfer into RIP‐mOVA mice. These findings suggest that use of IL‐27 to modulate autoimmune diseases might have limited therapeutic efficacy if autoaggressive Tc17 cells have already developed.
IL-27 counters the effect of TGF-beta+IL-6 on naive CD4(+) T cells, resulting in near complete inhibition of de novo Th17 development. In contrast, little is known about the effect of IL-27 on ...already differentiated Th17 cells. A better understanding of how IL-27 regulates these cells is needed to evaluate the therapeutic potential of IL-27 in Th17 cells-associated diseases. In this study, we show that IL-27 had surprisingly little effect on committed Th17 cells, despite its expression of a functional IL-27R. Contrary to de novo differentiation of Th17 cells, IL-27 did not suppress expression of retinoid-related orphan receptor (ROR)gammat or RORalpha in committed Th17 cells. Consistent with this finding, the frequency of committed Th17 cells and their cytokine secretion remained unaffected by IL-27. Both memory Th17 cells (CD4(+)CD25(-)CD62L(low)) that developed in vivo and encephalitogenic Th17 cells infiltrating the CNS of mice developing experimental autoimmune encephalomyelitis produced similar amounts of IL-17A when reactivated with IL-23 in the absence and presence of exogenous IL-27. Finally, IL-27 failed to suppress encephalitogenicity of Th17 cells in an adoptive transfer of experimental autoimmune encephalomyelitis. Analysis ex vivo of transferred Th17 cells in the spleen and CNS of recipient mice showed that cells retained similar phenotype irrespective of whether cells were treated or not with IL-27. Our data demonstrate that in contrast to inhibition of de novo differentiation of Th17 cells, IL-27 has little or no effect on committed Th17 cells. These findings indicate that therapeutic applications of IL-27 might have a limited efficacy in inflammatory conditions where aggressive Th17 responses have already developed.
The signals controlling marginal zone (MZ) and follicular (FO) B cell development remain incompletely understood. Here, we show that AKT orchestrates MZ B cell formation in mice and humans. Genetic ...models that increase AKT signaling in B cells or abolish its impact on FoxO transcription factors highlight the AKT-FoxO axis as an on-off switch for MZ B cell formation in mice. In humans, splenic immunoglobulin (Ig) D+CD27+ B cells, proposed as an MZ B cell equivalent, display higher AKT signaling than naive IgD+CD27− and memory IgD−CD27+ B cells and develop in an AKT-dependent manner from their precursors in vitro, underlining the conservation of this developmental pathway. Consistently, CD148 is identified as a receptor indicative of the level of AKT signaling in B cells, expressed at a higher level in MZ B cells than FO B cells in mice as well as humans.
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•AKT signaling in B cells drives MZ B cell development•FoxO1 inactivation is necessary for MZ B cell development•AKT is also distinctively increased in human IgD+CD27+ MZ B cells•CD148 is expressed at higher levels in MZ B cells than FO B cells in mice and humans
Cox et al. show that AKT activation biases B cell development toward marginal zone (MZ) B cells with innate functions. CD148 is identified as a receptor indicative of AKT signaling level in B cells, expressed at higher levels in MZ than FO B cells in mice and humans.
Muscle‐invasive forms of urothelial carcinomas are responsible for most mortality in bladder cancer. Finding new treatments for invasive bladder tumours requires adequate animal models to decipher ...the mechanisms of progression, in particular the way tumours interact with their microenvironment. Herein, using the murine bladder tumour cell line MB49 and its more aggressive variant MB49‐I, we demonstrate that the adaptive immune system efficiently limits progression of MB49, whereas MB49‐I has lost tumour antigens and is insensitive to adaptive immune responses. Furthermore, we unravel a parallel mechanism developed by MB49‐I to subvert its environment: de novo secretion of the proteoglycan decorin. We show that decorin overexpression in the MB49/MB49‐I model is required for efficient progression, by promoting angiogenesis and tumour cell invasiveness. Finally, we show that these results are relevant to muscle‐invasive human bladder carcinomas, which overexpress decorin together with angiogenesis‐ and adhesion/migration‐related genes, and that decorin overexpression in the human bladder carcinoma cell line TCCSUP is required for efficient invasiveness in vitro. We thus propose decorin as a new therapeutic target for these aggressive tumours.
Only a small fraction of patients with non‐invasive bladder cancer respond well to therapy. This study shows that the adaptive immune system cannot control invasive bladder tumors, while Decorin is found critical for this cancer progression.
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