The endogenous metabolite itaconate has recently emerged as a regulator of macrophage function, but its precise mechanism of action remains poorly understood. Here we show that itaconate is required ...for the activation of the anti-inflammatory transcription factor Nrf2 (also known as NFE2L2) by lipopolysaccharide in mouse and human macrophages. We find that itaconate directly modifies proteins via alkylation of cysteine residues. Itaconate alkylates cysteine residues 151, 257, 288, 273 and 297 on the protein KEAP1, enabling Nrf2 to increase the expression of downstream genes with anti-oxidant and anti-inflammatory capacities. The activation of Nrf2 is required for the anti-inflammatory action of itaconate. We describe the use of a new cell-permeable itaconate derivative, 4-octyl itaconate, which is protective against lipopolysaccharide-induced lethality in vivo and decreases cytokine production. We show that type I interferons boost the expression of Irg1 (also known as Acod1) and itaconate production. Furthermore, we find that itaconate production limits the type I interferon response, indicating a negative feedback loop that involves interferons and itaconate. Our findings demonstrate that itaconate is a crucial anti-inflammatory metabolite that acts via Nrf2 to limit inflammation and modulate type I interferons.
Genetic disruption of Nrf2 greatly enhances susceptibility to prooxidant- and carcinogen-induced experimental models of various human disorders; but the mechanisms by which this transcription factor ...confers protection are unclear. Using Nrf2-proficient (Nrf2(+/+)) and Nrf2-deficient (Nrf2(-/-)) primary epithelial cultures as a model, we now show that Nrf2 deficiency leads to oxidative stress and DNA lesions, accompanied by impairment of cell-cycle progression, mainly G(2)/M-phase arrest. Both N-acetylcysteine and glutathione (GSH) supplementation ablated the DNA lesions and DNA damage-response pathways in Nrf2(-/-) cells; however only GSH could rescue the impaired colocalization of mitosis-promoting factors and the growth arrest. Akt activation was deregulated in Nrf2(-/-) cells, but GSH supplementation restored it. Inhibition of Akt signaling greatly diminished the GSH-induced Nrf2(-/-) cell proliferation and wild-type cell proliferation. GSH depletion impaired Akt signaling and mitosis-promoting factor colocalization in Nrf2(+/+) cells. Collectively, our findings uncover novel functions for Nrf2 in regulating oxidative stress-induced cell-cycle arrest, especially G(2)/M-checkpoint arrest, and proliferation, and GSH-regulated redox signaling and Akt are required for this process.
In an experiment performed at Lawrence Berkeley National Laboratory's 88-inch cyclotron, the isotope 244Md was produced in the 209Bi (40Ar , 5n) reaction. Decay properties of 244Md were measured at ...the focal plane of the Berkeley Gas-filled Separator, and the mass number assignment of A = 244 was confirmed with the apparatus for the identification of nuclide A . The isotope 244Md is reported to have one, possibly two, α -decaying states with α energies of 8.66(2) and 8.31(2) MeV and half-lives of 0.4 + 0.4 − 0.1 and ∼ 6 s , respectively. Additionally, first evidence of the α decay of 236Bk was observed and is reported.
Background: TF is highly expressed in cancerous and atherosclerotic lesions. Monocyte recruitment is a hallmark of disease progression in these pathological states. Objective: To examine the role of ...integrin signaling in TF‐dependent recruitment of monocytes by endothelial cells. Methods: The expression of flTF and asTF in cervical cancer and atherosclerotic lesions was examined. Biologic effects of the exposure of primary microvascular endothelial cells (MVEC) to truncated flTF ectodomain (LZ‐TF) and recombinant asTF were assessed. Results: flTF and asTF exhibited nearly identical expression patterns in cancer lesions and lipid‐rich plaques. Tumor lesions, as well as stromal CD68+ monocytes/macrophages, expressed both TF forms. Primary MVEC rapidly adhered to asTF and LZ‐TF, and this was completely blocked by anti‐β1 integrin antibody. asTF‐ and LZ‐TF‐treatment of MVEC promoted adhesion of peripheral blood mononuclear cells (PBMCs) under orbital shear conditions and under laminar flow; asTF‐elicited adhesion was more pronounced than that elicited by LZ‐TF. Expression profiling and western blotting revealed a broad activation of cell adhesion molecules (CAMs) in MVEC following asTF treatment including E‐selectin, ICAM‐1 and VCAM‐1. In transwell assays, asTF potentiated PMBC migration through MVEC monolayers by ∼3‐fold under MCP‐1 gradient. Conclusions: TF splice variants ligate β1 integrins on MVEC, which induces the expression of CAMs in MVEC and leads to monocyte adhesion and transendothelial migration. asTF appears more potent than flTF in eliciting these effects. Our findings underscore the pathophysiologic significance of non‐proteolytic, integrin‐mediated signaling by the two naturally occurring TF variants in cancer and atherosclerosis.
Essentials
von Willebrands factor (VWF) glycosylation plays a key role in modulating in vivo clearance.
VWF glycoforms were used to examine the role of specific glycan moieties in regulating ...clearance.
Reduction in sialylation resulted in enhanced VWF clearance through asialoglycoprotein receptor.
Progressive VWF N‐linked glycan trimming resulted in increased macrophage‐mediated clearance.
Click to hear Dr Denis discuss clearance of von Willebrand factor in a free presentation from the ISTH Academy
Summary
Background
Enhanced von Willebrand factor (VWF) clearance is important in the etiology of both type 1 and type 2 von Willebrand disease (VWD). In addition, previous studies have demonstrated that VWF glycans play a key role in regulating in vivo clearance. However, the molecular mechanisms underlying VWF clearance remain poorly understood.
Objective
To define the molecular mechanisms through which VWF N‐linked glycan structures influence in vivo clearance.
Methods
By use of a series of exoglycosidases, different plasma‐derived VWF (pd‐VWF) glycoforms were generated. In vivo clearance of these glycoforms was then assessed in VWF−/− mice in the presence or absence of inhibitors of asialoglycoprotein receptor (ASGPR), or following clodronate‐induced macrophage depletion.
Results
Reduced amounts of N‐linked and O‐linked sialylation resulted in enhanced pd‐VWF clearance modulated via ASGPR. In addition to this role of terminal sialylation, we further observed that progressive N‐linked glycan trimming also resulted in markedly enhanced VWF clearance. Furthermore, these additional N‐linked glycan effects on clearance were ASGPR‐independent, and instead involved enhanced macrophage clearance that was mediated, at least in part, through LDL receptor‐related protein 1.
Conclusion
The carbohydrate determinants expressed on VWF regulate susceptibility to proteolysis by ADAMTS‐13. In addition, our findings now further demonstrate that non‐sialic acid carbohydrate determinants expressed on VWF also play an unexpectedly important role in modulating in vivo clearance through both hepatic ASGPR‐dependent and macrophage‐dependent pathways. In addition, these data further support the hypothesis that variation in VWF glycosylation may be important in the pathophysiology underlying type 1C VWD.
.
A segmented Si-telescope and HPGe array, STARS-LIBERACE, was used to study the
156
Gd(
p
,
t
γ
)
154
Gd direct reaction by particle-
γ
coincidence spectroscopy. New cross sections with a 25MeV ...proton beam are reported and compared to previous (p,t) and (t,p) studies. Furthermore, additional evidence for coexisting
K
π
=
0
1
+
,
2
1
+
and
0
2
+
,
2
2
+
configurations at
N
= 90 is presented. Direct and indirect population patterns of the low-lying states are also explored. Review of the new and existing evidence favors an interpretation based on a configuration-dependent pairing interaction. The weakening of monopole pairing strength and an increase in quadrupole pairing strength could bring 2p-2h
0
+
states below
2
Δ
. This may account for a large number of the low-lying
0
+
states observed in two-nucleon transfer reactions. A hypothesis for the origin of the
0
2
+
and
0
3
+
states is provided.
Summary
Background
Enhanced von Willebrand factor (VWF) clearance is important in the etiology of type 1 and type 2 von Willebrand disease (VWD). More than 20 different VWF point mutations have ...already been reported in patients with enhanced clearance. These include the VWD‐Vicenza variant, which is characterized by an Arg1205His substitution in the VWF D3 domain. Critically, however, the molecular mechanisms through which single amino acid substitutions in VWF result in enhanced clearance of this complex multimeric glycoprotein have not been defined.
Objectives
In this study, we have investigated the biological basis underlying the enhanced clearance of the VWF‐R1205H variant.
Methods
Using VWF−/− mice, in vivo clearance rates were determined for a series of full‐length and truncated recombinant VWF variants. In addition, the role of macrophages in modulating enhanced VWD‐Vicenza clearance was investigated using clodronate liposome administration.
Results
Our findings demonstrate that substitutions of R1205 with histidine, cysteine or serine all result in markedly reduced survival of full‐length recombinant VWF. Importantly, D'A3 fragments containing these same R1205 substitutions also demonstrated significantly enhanced clearance. In contrast to the reduced in vivo survival observed with R1205H, clearance of R1204H was not enhanced. Recent studies have demonstrated that hepatic and splenic macrophages play key roles in regulating VWF clearance. Importantly, macrophage‐depletion also served to markedly attenuate the enhanced clearance phenotypes associated with VWF‐R1205H, VWF‐R1205S and VWF‐R1205C.
Conclusions
Collectively, these novel findings demonstrate a specific and critical role for the R1205 residue in modulating macrophage‐mediated clearance of VWF in vivo.
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