The loss of endothelial connective integrity and endothelial barrier dysfunction can lead to increased vascular injury, which is related to the activation of endothelial inflammasomes. There are evidences that low concentrations of aspirin can effectively prevent cardiovascular diseases. We hypothesized that low-dose aspirin could ameliorate endothelial injury by inhibiting the activation of NLRP3 inflammasomes and ultimately prevent cardiovascular diseases. Microvascular endothelial cells were stimulated by lipopolysaccharide (2 μg/mL) and administrated by 0.1–2 mmol/L aspirin. The wild type mice were stimulated with LPS (100 μg/kg/day), and 1 h later treated with aspirin (12.5, 62.5, or 125 mg/kg/day) and dexamethasone (0.0182 mg/kg/day) for 7 days. Plasma and heart were harvested for measurement of ELISA and immunofluorescence analyses. We found that aspirin could inhibit NLRP3 inflammasome formation and activation
in vitro
in dose-dependent manner and has correlation between the NLRP3 inflammasome and the ROS/TXNIP pathway. We also found that low-concentration aspirin could inhibit the formation and activation of NLRP3 inflammasome and restore the expression of the endothelial tight junction protein zonula occludens-1/2 (ZO1/2). We assume that aspirin can ameliorate the endothelial layer dysfunction by suppressing the activation of NLRP3 inflammasome.
In variational inference (VI), coordinate-ascent and gradient-based approaches are two major types of algorithms for approximating difficult-to-compute probability densities. In real-world implementations of complex models, Monte Carlo methods are widely used to estimate expectations in coordinate-ascent approaches and gradients in derivative-driven ones. We discuss a Monte Carlo coordinate ascent VI (MC-CAVI) algorithm that makes use of Markov chain Monte Carlo (MCMC) methods in the calculation of expectations required within coordinate ascent VI (CAVI). We show that, under regularity conditions, an MC-CAVI recursion will get arbitrarily close to a maximiser of the evidence lower bound with any given high probability. In numerical examples, the performance of MC-CAVI algorithm is compared with that of MCMC and-as a representative of derivative-based VI methods-of Black Box VI (BBVI). We discuss and demonstrate MC-CAVI's suitability for models with hard constraints in simulated and real examples. We compare MC-CAVI's performance with that of MCMC in an important complex model used in nuclear magnetic resonance spectroscopy data analysis-BBVI is nearly impossible to be employed in this setting due to the hard constraints involved in the model.
Background
A recent study has reported that patients with nonalcoholic fatty liver disease (NAFLD) are more susceptible to coronary microvascular dysfunction (CMD), which may predict major adverse cardiac events. However, little is known regarding the causes of CMD during NAFLD. In this study, we aimed to explore the role of hepatic small extracellular vesicles (sEVs) in regulating the endothelial dysfunction of coronary microvessels during NAFLD.
Results
We established two murine NAFLD models by feeding mice a methionine-choline-deficient (MCD) diet for 4 weeks or a high-fat diet (HFD) for 16 weeks. We found that the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-dependent endothelial hyperpermeability occurred in coronary microvessels during both MCD diet and HFD-induced NAFLD. The in vivo and in vitro experiments proved that novel-microRNA(miR)-7-abundant hepatic sEVs were responsible for NLRP3 inflammasome-dependent endothelial barrier dysfunction. Mechanistically, novel-miR-7 directly targeted lysosomal associated membrane protein 1 (LAMP1) and promotes lysosomal membrane permeability (LMP), which in turn induced Cathepsin B-dependent NLRP3 inflammasome activation and microvascular endothelial hyperpermeability. Conversely, a specific novel-miR-7 inhibitor markedly improved endothelial barrier integrity. Finally, we proved that steatotic hepatocyte was a significant source of novel-miR-7-contained hepatic sEVs, and steatotic hepatocyte-derived sEVs were able to promote NLRP3 inflammasome-dependent microvascular endothelial hyperpermeability through novel-miR-7.
Conclusions
Hepatic sEVs contribute to endothelial hyperpermeability in coronary microvessels by delivering novel-miR-7 and targeting the LAMP1/Cathepsin B/NLRP3 inflammasome axis during NAFLD. Our study brings new insights into the liver-to-microvessel cross-talk and may provide a new diagnostic biomarker and treatment target for microvascular complications of NAFLD.
Graphical Abstract
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