Identification of undescribed Relb expression domains in the murine brain by new Relb:cre-katushka reporter mice.
Developmental dynamics : an official publication of the American Association of Anatomists
The Heparan Sulfate Mimetic PG545 Modulates T Cell Responses and Prevents Delayed-Type Hypersensitivity.
Frontiers in immunology
2020; 11: 132
Noncanonical NF-?B signaling through activation of the transcription factor RelB acts as key regulator of cell lineage determination and differentiation in various tissues including the immune system. To elucidate temporospatial aspects of Relb expression, we generated a BAC transgenic knock-in mouse expressing the fluorescent protein Katushka and the enzyme Cre recombinase under control of the murine Relb promoter (Relb Cre-Kat mice).Co-expression of Katushka and Relb in fibroblast cultures and tissues of transgenic mice revealed highly specific reporter functions of the transgene. Crossing Relb Cre-Kat mice with ROSA26R reporter mice that allow for Cre-mediated consecutive ?-galactosidase or YFP synthesis identified various Relb expression domains in perinatal and mature mice. Besides thymus and spleen, highly specific expression patterns were found in different neuronal domains, as well as in other nonimmune organs including skin, skeletal structures and kidney. De novo Relb expression in the mature brain was confirmed in conditional knockout mice with neuro-ectodermal Relb deletion.Our results demonstrate the usability of Relb Cre-Kat reporter mice for the detection of de novo and temporarily restricted Relb expression including cell and lineage tracing of Relb expressing cells. Relb expression during mouse embryogenesis and at adulthood suggests, beyond immunity, important functions of this transcription factor in neurodevelopment and CNS function.
View details for DOI 10.1002/dvdy.170
View details for PubMedID 32145043
Natural Tr1-like cells do not confer long-term tolerogenic memory.
The heparan sulfate mimetic PG545 (pixatimod) is under evaluation as an inhibitor of angiogenesis and metastasis including in human clinical trials. We have examined the effects of PG545 on lymphocyte phenotypes and function. We report that PG545 treatment suppresses effector T cell activation and polarizes T cells away from Th17 and Th1 and toward Foxp3+ regulatory T cell subsets in vitro and in vivo. Mechanistically, PG545 inhibits Erk1/2 signaling, a pathway known to affect both T cell activation and subset polarization. Interestingly, these effects are also observed in heparanase-deficient T cells, indicating that PG545 has effects that are independent of its role in heparanase inhibition. Consistent with these findings, administration of PG545 in a Th1/Th17-dependent mouse model of a delayed-type hypersensitivity led to reduced footpad inflammation, reduced Th17 memory cells, and an increase in FoxP3+ Treg proliferation. PG545 also promoted Foxp3+ Treg induction by human T cells. Finally, we examined the effects of other heparan sulfate mimetics PI-88 and PG562 on lymphocyte polarization and found that these likewise induced Foxp3+ Treg in vitro but did not reduce Th17 numbers or improve delayed-type hypersensitivity in this model. Together, these data indicate that PG545 is a potent inhibitor of Th1/Th17 effector functions and inducer of FoxP3+ Treg. These findings may inform the adaptation of PG545 for clinical applications including in inflammatory pathologies associated with type IV hypersensitivity responses.
View details for DOI 10.3389/fimmu.2020.00132
View details for PubMedID 32117279
View details for PubMedCentralID PMC7015948
Alternative NF-?B signaling controls peripheral homeostasis and function of regulatory T cells.
IL-10-producing Tr1 cells promote tolerance but their contributions to tolerogenic memory are unclear. Using 10BiT mice that carry a Foxp3-eGFP reporter and stably express CD90.1 following IL-10 production, we characterized the spatiotemporal dynamics of Tr1 cells in a house dust mite model of allergic airway inflammation. CD90.1+Foxp3-IL-10+ Tr1 cells arise from memory cells and rejoin the tissue-resident memory T-cell pool after cessation of IL-10 production. Persistent antigenic stimulation is necessary to sustain IL-10 production and Irf1 and Batf expression distinguishes CD90.1+Foxp3-IL-10+ Tr1 cells from CD90.1+Foxp3-IL-10- 'former' Tr1. Depletion of Tr1-like cells after primary sensitization exacerbates allergic airway inflammation. However, neither transfer nor depletion of former Tr1 cells influences either Tr1 numbers or the inflammatory response during subsequent allergen memory re-challenge weeks later. Together these data suggest that naturally-arising Tr1 cells do not necessarily give rise to more Tr1 upon allergen re-challenge or contribute to tolerogenic memory. This phenotypic instability may limit efforts to re-establish tolerance by expanding Tr1 in vivo.
View details for DOI 10.7554/eLife.44821
View details for PubMedID 31603425
A new RelB-dependent CD117(+)CD172a(+) murine DC subset preferentially induces Th2 differentiation and supports airway hyperresponses in vivo
EUROPEAN JOURNAL OF IMMUNOLOGY
2018; 48 (6): 923?36
Regulatory T cells (Tregs) maintain immune homeostasis and play an important role in tissue regeneration after injury. Mutations affecting development or homeostasis of Tregs lead to immune pathologies in humans and are often fatal in mouse models. Although the pathways required for Treg development are being increasingly characterized, factors crucial for Treg homeostasis are not completely understood. Previously we have found a role for alternative NF-?B pathway in restricting T cell activation and Th17 differentiation. Here, by using the mouse model of uncontrolled alternative NF-?B signaling we identify a crucial intrinsic role of RelB signaling in regulating homeostasis and competitive fitness of Tregs. The failure of p100-/- Tregs to maintain the population of effector Tregs and efficiently suppress immune reactions results in lethal multiorgan Th1-mediated inflammation in Rag1-/- recipients. This inflammation is combined with severe lymphopenia and could be rescued by adoptive transfer of wild type Tregs. Thus in addition to its role in Th17 differentiation, RelB acts as a potent inhibitor of Treg effector functions. Our results point to RelB as a potential therapeutic target for Treg manipulation.
View details for DOI 10.1016/j.imbio.2019.06.001
View details for PubMedID 31200979
RelB regulates Th17 differentiation in a cell-intrinsic manner
2018; 223 (2): 191?99
The NF-?B transcription factor subunit RelB is important for the full activation of conventional dendritic cells (cDCs) during T-cell-dependent immune responses. Although the number of splenic DCs is greatly reduced in RelBnull mice, the cause and consequences of this deficiency are currently unknown. To circumvent the impact of the pleiotropic defects in RelBnull mice we used a reporter model for RelB expression (RelBKatushka mice) and conditionally deleted RelB in DCs (RelBCD11c-Cre mice). Thereby, we can show here that RelB is essential for the differentiation of a CD117+ CD172a+ cDC subpopulation that highly expresses RelB. Surprisingly, these DCs depend on p50 for their development and are negatively regulated by a constitutive p52 activation in absence of p100. The absence of p52/p100 had no influence on the homeostasis of CD117+ CD172a+ cDCs. RelB-dependent CD117+ CD172a+ DCs strongly induce the production of the type 2 cytokines IL-4 and IL-13, as well as GM-CSF from naïve Th cells. Consequently, mice lacking RelB in cDCs show an attenuated bronchial hyperresponsiveness with reduced eosinophil infiltration. Taken together, we have identified a new splenic RelB-dependent CD117+ CD172a+ cDC population that preferentially induces Th2 responses.
View details for DOI 10.1002/eji.201747332
View details for Web of Science ID 000434963700004
View details for PubMedID 29485182
Dietary restriction improves repopulation but impairs lymphoid differentiation capacity of hematopoietic stem cells in early aging
JOURNAL OF EXPERIMENTAL MEDICINE
2016; 213 (4): 535?53
The role of the alternative NF-?B pathway is mainly attributed to the lymphoid organ formation and blood cancer. However, its involvement in lymphocyte differentiation is not clearly defined. Recently, we have shown that uncontrolled activation of alternative NF-?B in mice lacking the NF-?B inhibitory protein p100 (p100-/- mice) hinders plasmablast proliferation and diminishes T cell independent responses. Here we show that hyperactivation of this pathway leads to a cell-intrinsic T cell defects. p100-deficient T helper cells displayed both an activation and a proliferation defect in vitro. In addition, memory T cell formation was impaired in vivo. Moreover, p100-/- T cells failed to polarize into T helper 17 cells. This phenotype was dependent on increased RelB activation and suboptimal ROR?t expression. Thus, our results demonstrate that RelB acts as a negative regulator of T cell activation and Th17 development. Targeting this pathway therefore could be beneficial in Th17-mediated pathologies.
View details for DOI 10.1016/j.imbio.2017.10.026
View details for Web of Science ID 000419263000006
View details for PubMedID 29050819
NF-kappa B2/p100 deficiency impairs immune responses to T- cell- independent type 2 antigens
EUROPEAN JOURNAL OF IMMUNOLOGY
2014; 44 (3): 662?72
Dietary restriction (DR) improves health, delays tissue aging, and elongates survival in flies and worms. However, studies on laboratory mice and nonhuman primates revealed ambiguous effects of DR on lifespan despite improvements in health parameters. In this study, we analyzed consequences of adult-onset DR (24 h to 1 yr) on hematopoietic stem cell (HSC) function. DR ameliorated HSC aging phenotypes, such as the increase in number of HSCs and the skewing toward myeloid-biased HSCs during aging. Furthermore, DR increased HSC quiescence and improved the maintenance of the repopulation capacity of HSCs during aging. In contrast to these beneficial effects, DR strongly impaired HSC differentiation into lymphoid lineages and particularly inhibited the proliferation of lymphoid progenitors, resulting in decreased production of peripheral B lymphocytes and impaired immune function. The study shows that DR-dependent suppression of growth factors and interleukins mediates these divergent effects caused by DR. Supplementation of insulin-like growth factor 1 partially reverted the DR-induced quiescence of HSCs, whereas IL-6/IL-7 substitutions rescued the impairment of B lymphopoiesis exposed to DR. Together, these findings delineate positive and negative effects of long-term DR on HSC functionality involving distinct stress and growth signaling pathways.
View details for DOI 10.1084/jem.20151100
View details for Web of Science ID 000373394100007
View details for PubMedID 26951333
View details for PubMedCentralID PMC4821645
Calixarene methylenebisphosphonic acids as inhibitors of fibrin polymerization
2011; 278 (8): 1244?51
Formation of the splenic marginal zone (MZ) depends on the alternative NF-?B signaling pathway. Recently, we reported that unrestricted activation of this pathway in NF-?B2/p100-deficient (p100(-/-) ) knock-in mice alters the phenotype of MZ stroma and B cells. Here, we show that lack of the p100 inhibitor resulted in an expansion of both MZ B and peritoneal B-1 cells. However, these cells failed to generate proliferating blasts in response to T-cell-independent type 2 (TI-2) Ags, correlating with dampened IgM and absent IgG3 responses. This phenotype was in part due to increased activity of the NF-?B subunit RelB. Moreover, p100(-/-) ?B6 BM chimeras were more susceptible to infection by encapsulated Streptococcus pneumoniae bacteria, pathogens that induce TI-2 responses. In contrast to the TI-2 defect, p100 deficiency did not impair immune responses to the TI-1 Ag LPS and p100(-/-) MZ B cells showed normal Ag transportation into B-cell follicles. Furthermore, p100(-/-) MZ B and B-1 cells failed to respond to TI-2 Ags in the presence of WT accessory cells. Thus, NF-?B2/p100 deficiency caused a predominant B-cell-intrinsic TI-2 defect that could largely be attributed to impaired proliferation of plasmablasts. Importantly, p100 was also necessary for efficient defense against clinically relevant TI-2 pathogens.
View details for DOI 10.1002/eji.201343484
View details for Web of Science ID 000332933200009
View details for PubMedID 24242887
Calixarenes bearing two or four methylenebisphosphonic acid groups at the macrocyclic upper rim have been studied with respect to their effects on fibrin polymerization. The most potent inhibitor proved to be calixarene tetrakis-methylene-bis-phosphonic acid (C-192), in which case the maximum rate of fibrin polymerization in the fibrinogen + thrombin reaction decreased by 50% at concentrations of 0.52 × 10(-6) M (IC(50)). At this concentration, the molar ratio of the compound to fibrinogen was 1.7 : 1. For the case of desAABB fibrin polymerization, the IC(50) was 1.26 × 10(-6) M at a molar ratio of C-192 to fibrin monomer of 4 : 1. Dipropoxycalixarene bis-methylene-bis-phosphonic acid (C-98) inhibited fibrin desAABB polymerization with an IC(50) = 1.31 × 10(-4) M. We hypothesized that C-192 blocks fibrin formation by combining with polymerization site 'A' (A?17-19), which ordinarily initiates protofibril formation in a 'knob-hole' manner. This suggestion was confirmed by an HPLC assay, which showed a host-guest inclusion complex of C-192 with the synthetic peptide Gly-Pro-Arg-Pro, an analogue of site 'A'. Further confirmation that the inhibitor was acting at the initial step of the reaction was obtained by electron microscopy, with no evidence of protofibril formation being evident. Calixarene C-192 also doubled both the prothrombin time and the activated partial thromboplastin time in normal human blood plasma at concentrations of 7.13 × 10(-5) M and 1.10 × 10(-5) M, respectively. These experiments demonstrate that C-192 is a specific inhibitor of fibrin polymerization and blood coagulation and can be used for the design of a new class of antithrombotic agents.
View details for DOI 10.1111/j.1742-4658.2011.08045.x
View details for Web of Science ID 000289151700007
View details for PubMedID 21294845