The atypical chemokine receptor 2 (ACKR2), also named D6, regulates local levels of inflammatory chemokines by internalization and degradation. To explore potential anti-inflammatory functions of ...ACKR2 in glomerulonephritis, we induced autologous nephrotoxic nephritis in C57/BL6 wild-type and Ackr2-deficient mice. Renal ACKR2 expression increased and localized to interstitial lymphatic endothelium during nephritis. At two weeks Ackr2–/–mice developed increased albuminuria and urea levels compared to wild-type mice. Histological analysis revealed increased structural damage in the glomerular and tubulointerstitial compartments within Ackr2−/− kidneys. This correlated with excessive renal leukocyte infiltration of CD4+ T cells and mononuclear phagocytes with increased numbers in the tubulointerstitium but not glomeruli in knockout mice. Expression of inflammatory mediators and especially markers of fibrotic tissue remodeling were increased along with higher levels of ACKR2 inflammatory chemokine ligands like CCL2 in nephritic Ackr2–/– kidneys. In vitro, Ackr2 deficiency in TNF-stimulated tubulointerstitial tissue but not glomeruli increased chemokine levels. These results are in line with ACKR2 expression in interstitial lymphatic endothelial cells, which also assures efflux of activated leukocytes into regional lymph nodes. Consistently, nephritic Ackr2–/– mice showed reduced adaptive cellular immune responses indicated by decreased regional T-cell activation. However, this did not prevent aggravated injury in the kidneys of Ackr2–/– mice with nephrotoxic nephritis due to simultaneously increased tubulointerstitial chemokine levels, leukocyte infiltration and fibrosis. Thus, ACKR2 is important in limiting renal inflammation and fibrotic remodeling in progressive nephrotoxic nephritis. Hence, ACKR2 may be a potential target for therapeutic interventions in immune complex glomerulonephritis.
Following renal ischemia-reperfusion injury (IRI), resolution of inflammation allows tubular regeneration, whereas ongoing inflammatory injury mediated by infiltrating leukocytes leads to nephron ...loss and renal fibrosis, typical hallmarks of chronic kidney disease. Atypical chemokine receptor 2 (ACKR2) is a chemokine decoy receptor that binds and scavenges inflammatory CC chemokines and reduces local leukocyte accumulation. We hypothesized that ACKR2 limits leukocyte infiltration, inflammation, and fibrotic tissue remodeling after renal IRI, thus preventing progression to chronic kidney disease. Compared with wild type, Ackr2 deficiency increases CC chemokine ligand 2 levels in tumor necrosis factor–stimulated tubulointerstitial tissue in vitro. In Ackr2-deficient mice with early IRI 1 or 5 days after transient renal pedicle clamping, tubular injury was similar to wild type, although accumulation of mononuclear phagocytes increased in postischemic Ackr2−/− kidneys. Regarding long-term outcomes, Ackr2−/− kidneys displayed more tubular injury 5 weeks after IRI, which was associated with persistently increased renal infiltrates of mononuclear phagocytes, T cells, Ly6Chigh inflammatory macrophages, and inflammation. Moreover, Ackr2 deficiency caused substantially aggravated renal fibrosis in Ackr2−/− kidneys 5 weeks after IRI, shown by increased expression of matrix molecules, renal accumulation of α-smooth muscle actin–positive myofibroblasts, and bone marrow–derived fibrocytes. ACKR2 is important in limiting persistent inflammation, tubular loss, and renal fibrosis after ischemic acute kidney injury and, thus, can prevent progression to chronic renal disease.
Background
The use of antibiotics during pregnancy is associated with increased allergic asthma risk in the offspring, and given that approximately 25% of pregnant women are prescribed antibiotics, ...it is important to understand the mechanisms contributing to this phenomenon. Currently, there are no studies that directly test this association experimentally. Our objective was to develop a mouse model in which antibiotic treatment during pregnancy results in increased offspring asthma susceptibility.
Methods
Pregnant mice were treated daily from gestation day 8‐17 with an oral solution of the antibiotic vancomycin, and three concentrations were tested. At weaning, offspring were subjected to an adjuvant‐free experimental asthma protocol using ovalbumin as an allergen. The composition of the gut microbiome was determined in mothers and offspring with samples collected from five different time points; short‐chain fatty acids were also analyzed in allergic offspring.
Results
We found that maternal antibiotic treatment during pregnancy was associated with increased offspring asthma severity in a dose‐dependent manner. Furthermore, maternal vancomycin treatment during pregnancy caused marked changes in the gut microbiome composition in both mothers and pups at several different time points. The increased asthma severity and intestinal microbiome changes in pups were also associated with significantly decreased cecal short‐chain fatty acid concentrations.
Conclusion
Consistent with the “Developmental Origins Hypothesis,” our results confirm that exposure to antibiotics during pregnancy shapes the neonatal intestinal environment and increases offspring allergic lung inflammation.
The rising prevalence of type 1 diabetes (T1D) over the past decades has been linked to lifestyle changes, but the underlying mechanisms are largely unknown. Recent findings point to gut-associated ...mechanisms in the control of T1D pathogenesis. In nonobese diabetic (NOD) mice, a model of T1D, diabetes development accelerates after deletion of the Toll-like receptor 4 (TLR4). We hypothesized that altered intestinal functions contribute to metabolic alterations, which favor accelerated diabetes development in TLR4-deficient (TLR4
−/−
) NOD mice. In 70–90-day-old normoglycemic (prediabetic) female NOD TLR4
+/+
and NOD TLR4
−/−
mice, gut morphology and microbiome composition were analyzed. Parameters of lipid metabolism, glucose homeostasis, and mitochondrial respiratory activity were measured
in vivo
and
ex vivo
. Compared with NOD TLR4
+/+
mice, NOD TLR4
−/−
animals showed lower muscle mass of the small intestine, higher abundance of Bacteroidetes, and lower Firmicutes in the large intestine, along with lower levels of circulating short-chain fatty acids (SCFA). These changes are associated with higher body weight, hyperlipidemia, and severe insulin and glucose intolerance, all occurring before the onset of diabetes. These mice also exhibited insulin resistance–related abnormalities of energy metabolism, such as lower total respiratory exchange rates and higher hepatic oxidative capacity. Distinct alterations of gut morphology and microbiota composition associated with reduction of circulating SCFA may contribute to metabolic disorders promoting the progression of insulin-deficient diabetes/T1D development.
Human neutrophil elastase is an important regulator of the immune response and plays a role in host defense mechanisms and further physiological processes. The uncontrolled activity of this serine ...protease may cause severe tissue alterations and impair inflammatory states. The design of an activity-based probe for human neutrophil elastase reported herein relies on a sulfonyloxyphthalimide moiety as a new type of warhead that is linker-connected to a coumarin fluorophore. The inhibitory potency of the activity-based probe was assessed against several serine and cysteine proteases, and the selectivity for human neutrophil elastase (K
= 6.85 nM) was determined. The adequate fluorescent tag of the probe allowed for the in-gel fluorescence detection of human neutrophil elastase in the low nanomolar range. The coumarin moiety and the anthranilic acid function of the probe, produced in the course of a Lossen rearrangement, were part of two different Förster resonance energy transfers.
Bacterial infection has been discussed as a potential etiologic factor in the pathophysiology of coronary heart disease (CHD). This study analyzes molecular phylogenies to systematically explore the ...presence, frequency, and diversity of bacteria in atherosclerotic lesions in patients with CHD.
We investigated 16S rDNA signatures in atherosclerotic tissue obtained through catheter-based atherectomy of 38 patients with CHD, control material from postmortem patients (n=15), and heart-beating organ donors (n=11) using clone libraries, denaturating gradient gel analysis, and fluorescence in situ hybridization. Bacterial DNA was found in all CHD patients by conserved PCR but not in control material or in any of the normal/unaffected coronary arteries. Presence of bacteria in atherosclerotic lesions was confirmed by fluorescence in situ hybridization. A high overall bacterial diversity of >50 different species, among them Staphylococcus species, Proteus vulgaris, Klebsiella pneumoniae, and Streptococcus species, was demonstrated in >1500 clones from a combined library and confirmed by denaturating gradient gel analysis. Mean bacterial diversity in atheromas was high, with a score of 12.33+/-3.81 (range, 5 to 22). A specific PCR detected Chlamydia species in 51.5% of CHD patients.
Detection of a broad variety of molecular signatures in all CHD specimens suggests that diverse bacterial colonization may be more important than a single pathogen. Our observation does not allow us to conclude that bacteria are the causative agent in the etiopathogenesis of CHD. However, bacterial agents could have secondarily colonized atheromatous lesions and could act as an additional factor accelerating disease progression.
The rising prevalence of type 1 diabetes (T1D) over the past decades has been linked to lifestyle changes, but the underlying mechanisms are largely unknown. Recent findings point to gut-associated ...mechanisms in the control of T1D pathogenesis. In nonobese diabetic (NOD) mice, a model of T1D, diabetes development accelerates after deletion of the Toll-like receptor 4 (TLR4). We hypothesized that altered intestinal functions contribute to metabolic alterations, which favor accelerated diabetes development in TLR4-deficient (TLR4−/−) NOD mice. In 70–90-day-old normoglycemic (prediabetic) female NOD TLR4+/+ and NOD TLR4−/− mice, gut morphology and microbiome composition were analyzed. Parameters of lipid metabolism, glucose homeostasis, and mitochondrial respiratory activity were measured in vivo and ex vivo. Compared with NOD TLR4+/+ mice, NOD TLR4−/− animals showed lower muscle mass of the small intestine, higher abundance of Bacteroidetes, and lower Firmicutes in the large intestine, along with lower levels of circulating short-chain fatty acids (SCFA). These changes are associated with higher body weight, hyperlipidemia, and severe insulin and glucose intolerance, all occurring before the onset of diabetes. These mice also exhibited insulin resistance–related abnormalities of energy metabolism, such as lower total respiratory exchange rates and higher hepatic oxidative capacity. Distinct alterations of gut morphology and microbiota composition associated with reduction of circulating SCFA may contribute to metabolic disorders promoting the progression of insulin-deficient diabetes/T1D development.
Report on the second Mock LISA data challenge Babak, Stanislav; Baker, John G; Benacquista, Matthew J ...
Classical and quantum gravity,
06/2008, Letnik:
25, Številka:
11
Journal Article, Conference Proceeding
Human neutrophil elastase is an important regulator of the immune response and plays a role in host defense mechanisms and further physiological processes. The uncontrolled activity of this serine ...protease may cause severe tissue alterations and impair inflammatory states. The design of an activity-based probe for human neutrophil elastase reported herein relies on a sulfonyloxyphthalimide moiety as a new type of warhead that is linker-connected to a coumarin fluorophore. The inhibitory potency of the activity-based probe was assessed against several serine and cysteine proteases, and the selectivity for human neutrophil elastase (K i = 6.85 nM) was determined. The adequate fluorescent tag of the probe allowed for the in-gel fluorescence detection of human neutrophil elastase in the low nanomolar range. The coumarin moiety and the anthranilic acid function of the probe, produced in the course of a Lossen rearrangement, were part of two different Förster resonance energy transfers.
The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of several data sets containing ...simulated instrument noise and gravitational-wave sources of undisclosed parameters. Participants are asked to analyze the data sets and report the maximum information about source parameters. The challenges are being released in rounds of increasing complexity and realism: in this proceeding we present the results of Challenge 2, issued in January 2007, which successfully demonstrated the recovery of signals from supermassive black-hole binaries, from ~20,000 overlapping Galactic white-dwarf binaries, and from the extreme-mass-ratio inspirals of compact objects into central galactic black holes.
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