A Phosphatase-Mimetic Nano-Stabilizer of Mast Cells for Long-Term Prevention of Allergic Disease.
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ABSTRACT:
SUBMITTER: Lin P
PROVIDER: S-EPMC8061383 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:WHO guidelines advocate breastfeeding for 6 months, and EAACI guideline recommends exclusive breastfeeding for 4-6 months. However, evidence for breastfeeding to prevent asthma and allergic disease is conflicting. We examined whether following recommended breastfeeding guidelines alters the long-term risks of asthma, eczema, rhinitis or atopy.The effect of nonexclusive (0, >0-6, >6 months) and exclusive breastfeeding (0, >0-4, >4 months) on repeated measures of asthma (10, 18 years), eczema, rhinitis, and atopy (1-or-2, 4, 10, 18 years) risks was estimated in the IoW cohort (n = 1456) using log-linear models with generalized estimating equations. The Food Allergy and Intolerance Research (FAIR) cohort (n = 988), also from the IoW, was examined to replicate results.Breastfeeding (any or exclusive) had no effect on asthma and allergic disease in the IoW cohort. In the FAIR cohort, any breastfeeding for >0-6 months protected against asthma at 10 years (RR = 0.50, 95% CI = 0.32-0.79, P = 0.003), but not other outcomes, whilst exclusive breastfeeding for >4 months protected against repeated rhinitis (RR = 0.36, 95% CI = 0.18-0.71, P = 0.003). Longer breastfeeding was protective against late-onset wheeze in the IoW cohort.The protective effects of nonexclusive and exclusive breastfeeding against long-term allergic outcomes were inconsistent between these colocated cohorts, agreeing with previous observations of heterogeneous effects. Although breastfeeding should be recommended for other health benefits, following breastfeeding guidelines did not appear to afford a consistent protection against long-term asthma, eczema, rhinitis or atopy. Further research is needed into the long-term effects of breastfeeding on allergic disease.
| S-EPMC4844826 | biostudies-other
Project description:Atopic dermatitis is a chronic inflammatory skin disease that affects 15-30% of children and approximately 5% of adults in industrialized countries. Although the pathogenesis of atopic dermatitis is not fully understood, the disease is mediated by an abnormal immunoglobulin-E immune response in the setting of skin barrier dysfunction. Mast cells contribute to immunoglobulin-E-mediated allergic disorders including atopic dermatitis. Upon activation, mast cells release their membrane-bound cytosolic granules leading to the release of several molecules that are important in the pathogenesis of atopic dermatitis and host defence. More than 90% of patients with atopic dermatitis are colonized with Staphylococcus aureus in the lesional skin whereas most healthy individuals do not harbour the pathogen. Several staphylococcal exotoxins can act as superantigens and/or antigens in models of atopic dermatitis. However, the role of these staphylococcal exotoxins in disease pathogenesis remains unclear. Here we report that culture supernatants of S. aureus contain potent mast-cell degranulation activity. Biochemical analysis identified ?-toxin as the mast cell degranulation-inducing factor produced by S. aureus. Mast cell degranulation induced by ?-toxin depended on phosphoinositide 3-kinase and calcium (Ca(2+)) influx; however, unlike that mediated by immunoglobulin-E crosslinking, it did not require the spleen tyrosine kinase. In addition, immunoglobulin-E enhanced ?-toxin-induced mast cell degranulation in the absence of antigen. Furthermore, S. aureus isolates recovered from patients with atopic dermatitis produced large amounts of ?-toxin. Skin colonization with S. aureus, but not a mutant deficient in ?-toxin, promoted immunoglobulin-E and interleukin-4 production, as well as inflammatory skin disease. Furthermore, enhancement of immunoglobulin-E production and dermatitis by ?-toxin was abrogated in Kit(W-sh/W-sh) mast-cell-deficient mice and restored by mast cell reconstitution. These studies identify ?-toxin as a potent inducer of mast cell degranulation and suggest a mechanistic link between S. aureus colonization and allergic skin disease.
| S-EPMC4090780 | biostudies-literature
Project description:OBJECTIVES:Compared with pain-free controls, patients with fibromyalgia (FM) have more mast cells in the skin. Whether mast cells are involved in the pathogenesis of FM is unclear. We sought to determine the effects of a mast cell stabilizer (ketotifen) on FM symptoms. MATERIALS AND METHODS:Fifty-one FM patients were randomized to daily oral ketotifen 2 mg bid (n=24) for 8 weeks or placebo (N=27). Mean age of patients was 51.2 years (SD=8.4); 88% were female and 88% were white; 22% were taking concomitant opiates; and mean pressure pain sensitivity (range, 0 to 20) was 10.0 (0.4). At study entry, the weekly average pain intensity was 6.4 (1.1) and the mean score on the Revised Fibromyalgia Impact Questionnaire-Revised was 66.8 (14.0). RESULTS:We found no statistically significant treatment group differences from baseline in either group for the 2 primary measures: weekly average pain intensity (ketotifen -1.3 [1.9] vs. placebo -1.5 [1.9], P=0.7); and Fibromyalgia Impact Questionnaire-Revised score (-12.1 [19.5] vs. -12.2 [18.1], P=0.9). No secondary outcome measures (Brief Pain Inventory pain intensity and pressure pain sensitivity) reached statistical significance; results did not differ in the intent-to-treat and completer analyses. Other than transient sedation (6 [28.6%] vs. 1 [4.0%]), ketotifen was well tolerated. DISCUSSION:The study results question whether skin mast cells play a major role in the pathogenesis of FM. However, given the role of mast cells in peripheral and central nociception, and the minimal side effects of ketotifen, a randomized clinical trial using increasing doses of ketotifen may be warranted.
| S-EPMC4417653 | biostudies-literature
Project description:Synaptic plasticity is an important mechanism that underlies learning and cognition. Protein phosphorylation by kinases and dephosphorylation by phosphatases play critical roles in the activity-dependent alteration of synaptic plasticity. In this study, we report that Wip1, a protein phosphatase, is essential for long-term potentiation (LTP) and long-term depression (LTD) processes. Wip1-deletion suppresses LTP and enhances LTD in the hippocampus CA1 area. Wip1 deficiency-induced aberrant elevation of CaMKII T286/287 and T305 phosphorylation underlies these dysfunctions. Moreover, we showed that Wip1 modulates CaMKII dephosphorylation. Wip1(-/-) mice exhibit abnormal GluR1 membrane expression, which could be reversed by the application of a CaMKII inhibitor, indicating that Wip1/CaMKII signaling is crucial for synaptic plasticity. Together, our results demonstrate that Wip1 phosphatase plays a vital role in regulating hippocampal synaptic plasticity by modulating the phosphorylation of CaMKII.
| S-EPMC4951180 | biostudies-literature
Project description:ObjectiveThe Centers for Medicare and Medicaid Services' National Partnership to Improve Dementia Care in Nursing Homes focuses on but is not limited to long-term care (LTC) residents with dementia; the potential impact on residents with other diagnoses is unclear. We sought to determine whether resident subpopulations experienced changes in antipsychotic and mood stabilizer prescribing.DesignRepeated cross-sectional analysis of a 20% Medicare sample, 2011-2014.Setting and participantFee-for-service Medicare beneficiaries with Part D coverage in LTC (n = 562,485) and a secondary analysis limited to persons with depression or bipolar disorder (n = 139,071).MethodsMain outcome was quarterly predicted probability of treatment with an antipsychotic or mood stabilizer.ResultsFrom 2011 to 2014, the adjusted predicted probability (APP) of antipsychotic treatment fell from 0.120 [95% confidence interval (CI) 0.119-0.121] to 0.100 (95% CI 0.099-0.101; P < .001). Use decreased for all age, sex, and racial/ethnic groups; the decline was larger for persons with dementia (P < .001). The APP of mood stabilizer use grew from 0.140 (95% CI 0.139-0.141) to 0.185 (95% CI 0.184-0.186), growth slightly larger among persons without dementia (P < .001). Among persons with depression or bipolar disorder, the APP of antipsychotic treatment increased from 0.081 (95% CI 0.079-0.082) to 0.087 (95% CI 0.085-0.088; P < .001); APP of mood stabilizer treatment grew more, from 0.193 (95% CI 0.190-0.196) to 0.251 (0.248-0.253; P < .001). Quetiapine was the most commonly prescribed antipsychotic. The most widely prescribed mood stabilizer was gabapentin, prescribed to 70.5% of those who received a mood stabilizer by the end of 2014.Conclusions and implicationsThe likelihood of antipsychotic and mood stabilizer treatment did not decline for residents with depression or bipolar disorder, for whom such prescribing may be appropriate but who were not excluded from the Partnership's antipsychotic quality measure. Growth in mood stabilizer use was widespread, and largely driven by growth in gabapentin prescribing.
| S-EPMC7641905 | biostudies-literature
Project description:Mast cells are major effector cells for allergic responses that act by releasing inflammatory mediators, such as histamine and pro-inflammatory cytokines. Accordingly, different strategies have been pursued to develop anti-allergic and anti-inflammatory candidates by regulating the function of mast cells. The purpose of this study was to determine the effectiveness of elaeocarpusin (EL) on mast cell-mediated allergic inflammation. We isolated EL from Elaeocarpus sylvestris L. (Elaeocarpaceae), which is known to possess anti-inflammatory properties. For this study, various sources of mast cells and mouse anaphylaxis models were used. EL suppressed the induction of markers for mast cell degranulation, such as histamine and ?-hexosaminidase, by reducing intracellular calcium levels. Expression of pro-inflammatory cytokines, such as tumor necrosis factor-? and IL-4, was significantly decreased in activated mast cells by EL. This inhibitory effect was related to inhibition of the phosphorylation of Fyn, Lyn, Syk, and Akt, and the nuclear translocation of nuclear factor-?B. To confirm the effect of EL in vivo, immunoglobulin E-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin-induced active systemic anaphylaxis (ASA) models were induced. EL reduced the PCA reaction in a dose dependent manner. In addition, EL attenuated ASA reactions such as hypothemia, histamine release, and IgE production. Our results suggest that EL is a potential therapeutic candidate for allergic inflammatory diseases that acts via the inhibition of mast cell degranulation and expression of proinflammatory cytokines.
| S-EPMC5999758 | biostudies-literature
Project description:Background and aimsDespite established guidelines on secondary prevention of cardiovascular disease, practical implementation of treatment targets is deficient even in high-income countries. This study compared long-term hospital-based treatment with follow-up at primary health care regarding new cardiovascular events and achievement of treatment targets.MethodsThis randomized controlled trial at Sørlandet Hospital, Norway 2007-2021 included patients hospitalized due to myocardial infarction (n = 760) or after scheduled percutaneous coronary intervention (PCI) (n = 677) or coronary artery bypass grafting (n = 103). Patients were randomized to hospital-based secondary preventive care with consultations 2 weeks, 3 months, 6 months and 1 year after the index event and annually for up to 5 years, or follow-up at primary health care. Final data was collected after 10 years and hazard ratios were calculated using Cox regression analyses.ResultsComposite endpoint-free survival due to a lower rate of PCI improved in patients with hospital-based follow-up (n = 788) compared to patients followed-up at primary health care (n = 752) (HR 0.80, 95% CI 0.66-0.96; p = 0.02) but all-cause mortality was not reduced (HR 0.96, 95% CI 0.59-1.56; p = 0.86). At 1 year, LDL-cholesterol (2.1 [SD 0.7] versus 2.3 [SD 0.8] mmol/l; p < 0.001) and systolic blood pressure (132 [SD 16] versus 142 [SD 20] mm/Hg; p < 0.001) were lower in the hospital-based group, and the differences remained significant during the first 5 years. Other secondary preventive measures (smoking cessation, physical activity, body weight, glucose control, drug adherence) did not differ.ConclusionsLong-term hospital-based secondary preventive follow-up improved composite endpoint-free survival, but not mortality. Substantial risk factors remained unaddressed. The beneficial effects on blood pressure and LDL-cholesterol disappeared after annual consultations ceased.Trial registrationThe study is registered in ClinicalTrials.gov (NCT00679237) May 16, 2008.
| S-EPMC8679993 | biostudies-literature
Project description:Cromolyn, widely characterized as a 'mast cell stabilizer', has been used in mice to investigate the biological roles of mast cells in vivo. However, it is not clear to what extent cromolyn can either limit the function of mouse mast cells or influence biological processes in mice independently of effects on mast cells. We confirmed that cromolyn (at 10 mg/kg in vivo or 10-100 ?M in vitro) can inhibit IgE-dependent mast cell activation in rats in vivo (measuring Evans blue extravasation in passive cutaneous anaphylaxis (PCA) and increases in plasma histamine in passive systemic anaphylaxis (PSA)) and in vitro (measuring peritoneal mast cell (PMC) ?-hexosaminidase release and prostaglandin D(2) synthesis). However, under the conditions tested, cromolyn did not inhibit those mast cell-dependent responses in mice. In mice, cromolyn also failed to inhibit the ear swelling or leukocyte infiltration at sites of PCA. Nor did cromolyn inhibit IgE-independent degranulation of mouse PMCs induced by various stimulators in vitro. At 100 mg/kg, a concentration 10 times higher than that which inhibited PSA in rats, cromolyn significantly inhibited the increases in plasma concentrations of mouse mast cell protease-1 (but not of histamine) during PSA, but had no effect on the reduction in body temperature in this setting. Moreover, this concentration of cromolyn (100 mg/kg) also inhibited LPS-induced TNF production in genetically mast cell-deficient C57BL/6-Kit(W-sh/W-sh) mice in vivo. These results question cromolyn's effectiveness and selectivity as an inhibitor of mast cell activation and mediator release in the mouse.
| S-EPMC3580174 | biostudies-literature
Project description: Not available
| S-EPMC6517017 | biostudies-literature
Project description:Studies of long-term potentiation (LTP) and long-term depression (LTD) strongly suggest that individual synapses can be bidirectionally modified. A central question is the biochemical mechanisms that make LTP and LTD persistent. Previous theoretical models have proposed that the autophosphorylation properties of CaMKII could underlie a bistable molecular switch that maintains LTP, and there is experimental support for this mechanism. In contrast, there has been comparatively little theoretical or experimental work regarding the mechanisms that maintain LTD. Several lines of evidence indicate that LTD is not simply a reversal of previous LTP but rather involves separate biochemical reactions. These findings indicate that a minimal model of the synapse must involve a tristable system. Here, we describe a phosphatase (PP2A) switch, which together with a kinase switch form a tristable system. PP2A can be activated by a Ca(2+)-dependent process but can also be phosphorylated and inactivated by CaMKII. When dephosphorylated, PP2A can dephosphorylate itself. We show that these properties can lead to a persistent increase in PP2A during LTD (as reported experimentally), thus forming a phosphatase switch. We show that the coupled PP2A and CaMKII switches lead to a tristable system in which the kinase activity is high in the LTP state; the PP2A activity is high in the LTD state, and neither activity is high in the basal state. Our results provide an explanation for the recent finding that inhibition of PP2A prevents LTD induction.
| S-EPMC2620235 | biostudies-literature