Function and design of the Nox1 system in vascular smooth muscle cells

Mitogen-Activated Protein Kinases SvPmk1 and SvMps1 Are Critical for Abiotic Stress Resistance, Development and Pathogenesis of Sclerotiophoma versabilis

Mitogen-activated protein kinase (MAPK) signaling pathways are evolutionarily conserved in eukaryotes and modulate responses to both internal and external stimuli. Pmk1 and Mps MAPK pathways regulate stress tolerance, vegetative growth and cell wall integrity in Saccharomyces cerevisiae and Pyricularia oryzae. Here, we deployed genetic and cell biology strategies to investigate the roles of the orthologs of Pmk1 and Mps1 in Sclerotiophoma versabilis (herein referred to as SvPmk1 and SvMps1, respectively). Our results showed that SvPmk1 and SvMps1 are involved in hyphal development, asexual reproduction and pathogenesis in S. versabilis. We found that ∆Svpmk1 and ∆Svmps1 mutants have significantly reduced vegetative growths on PDA supplemented with osmotic stress-inducing agents, compared to the wild type, with ∆Svpmps1 being hypersensitive to hydrogen peroxide. The two mutants failed to produce pycnidia and have reduced pathogenicity on Pseudostellaria heterophylla. Unlike SvPmk1, SvMps1 was found to be indispensable for the fungal cell wall integrity. Confocal microscopic analyses revealed that SvPmk1 and SvMps1 are ubiquitously expressed in the cytosol and nucleus. Taken together, we demonstrate here that SvPmk1 and SvMps1 play critical roles in the stress resistance, development and pathogenesis of S. versabilis.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Mechanisms underlying unidirectional laminar shear stress-mediated Nrf2 activation in endothelial cells: Amplification of low shear stress signaling by primary cilia

Endothelial cells are sensitive to mechanical stress and respond differently to oscillatory flow versus unidirectional flow. This review highlights the mechanisms by which a wide range of unidirectional laminar shear stress induces activation of the redox sensitive antioxidant transcription factor nuclear factor-E2-related factor 2 (Nrf2) in cultured endothelial cells. We propose that fibroblast growth factor-2 (FGF-2), brain-derived neurotrophic factor (BDNF) and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) are potential Nrf2 activators induced by laminar shear stress. Shear stress-dependent secretion of FGF-2 and its receptor-mediated signaling is tightly controlled, requiring neutrophil elastase released by shear stress, αvβ3 integrin and the cell surface glycocalyx. We speculate that primary cilia respond to low laminar shear stress (<10 dyn/cm2), resulting in secretion of insulin-like growth factor 1 (IGF-1), which facilitates αvβ3 integrin-dependent FGF-2 secretion. Shear stress induces generation of heparan-binding epidermal growth factor-like growth factor (HB-EGF), which contributes to FGF-2 secretion and gene expression. Furthermore, HB-EGF signaling modulates FGF-2-mediated NADPH oxidase 1 activation that favors casein kinase 2 (CK2)-mediated phosphorylation/activation of Nrf2 associated with caveolin 1 in caveolae. Higher shear stress (>15 dyn/cm2) induces vesicular exocytosis of BDNF from endothelial cells, and we propose that BDNF via the p75NTR receptor could induce CK2-mediated Nrf2 activation. Unidirectional laminar shear stress upregulates gene expression of FGF-2 and BDNF and generation of 15d-PGJ2, which cooperate in sustaining Nrf2 activation to protect endothelial cells against oxidative damage.

Reactive Oxygen Species (ROS), Intimal Thickening, and Subclinical Atherosclerotic Disease

Arteriosclerosis causes significant morbidity and mortality worldwide. Central to this process is the development of subclinical non-atherosclerotic intimal lesions before the appearance of pathologic intimal thickening and advanced atherosclerotic plaques. Intimal thickening is associated with several risk factors, including oxidative stress due to reactive oxygen species (ROS), inflammatory cytokines and lipid. The main ROS producing systems in-vivo are reduced nicotinamide dinucleotide phosphate (NADPH) oxidase (NOX). ROS effects are context specific. Exogenous ROS induces apoptosis and senescence, whereas intracellular ROS promotes stem cell differentiation, proliferation, and migration. Lineage tracing studies using murine models of subclinical atherosclerosis have revealed the contributory role of medial smooth muscle cells (SMCs), resident vascular stem cells, circulating bone-marrow progenitors and endothelial cells that undergo endothelial-mesenchymal-transition (EndMT). This review will address the putative physiological and patho-physiological roles of ROS in controlling vascular cell fate and ROS contribution to vascular regeneration and disease progression.

Mechanisms of N‑acetylcysteine in reducing monocrotaline‑induced pulmonary hypertension in rats: Inhibiting the expression of Nox1 in pulmonary vascular smooth muscle cells

The aim of the present study was to investigate the impact of N‑acetylcysteine (NAC) on the expression of reduced nicotinamide adenine dinucleotide phosphate oxidase 1 (Nox1), and the proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) in rats exhibiting monocrotaline (MCT)‑induced pulmonary hypertension, and to investigate the possible mechanisms and treatment roles of NAC in pulmonary vascular remodeling (PVR). A total of 18 Wistar rats were randomly divided into three groups: The control (C) group; the MCT (M) group; and the NAC (N) group. The right ventricular hypertrophy index (RVHI) and other indicators were recorded 6 weeks subsequently. Groups C and M were divided into two subgroups: Groups C1 and M1 (control); and group C2 and M2 group (treated with ML171). Group N was not sub‑divided. PASMCs were isolated, and the vascular remodeling and Nox1 positioning were observed. The expression of Nox mRNA in each group, and the proliferation, apoptosis, and superoxide dismutase (SOD) activity of PASMCs, prior to and following the ML171 treatment, were measured. NAC was able to decrease RVHI and other indicators (P<0.001). The mRNA expression of Nox1 and Nox4 in group M was significantly increased compared with group C (P<0.05), and NAC was able to significantly decrease the expression of these two factors in lung tissue (P<0.001). MCT‑PASMCs exhibited differences in Nox1 mRNA expression (P<0.001), and the total SOD activity was Nox1‑dependently increased (r=0.949; P<0.001). NAC was able to decrease Nox1‑derived reactive oxygen species in PASMCs, thereby improving PVR. Nox1 was able to increase SOD activity, thereby demonstrating its positive effect on the proliferation of MCT‑PASMCs.

Perspective: On the importance of hydrodynamic interactions in the subcellular dynamics of macromolecules

An outstanding challenge in computational biophysics is the simulation of a living cell at molecular detail. Over the past several years, using Stokesian dynamics, progress has been made in simulating coarse grained molecular models of the cytoplasm. Since macromolecules comprise 20%-40% of the volume of a cell, one would expect that steric interactions dominate macromolecular diffusion. However, the reduction in cellular diffusion rates relative to infinite dilution is due, roughly equally, to steric and hydrodynamic interactions, HI, with nonspecific attractive interactions likely playing rather a minor role. HI not only serve to slow down long time diffusion rates but also cause a considerable reduction in the magnitude of the short time diffusion coefficient relative to that at infinite dilution. More importantly, the long range contribution of the Rotne-Prager-Yamakawa diffusion tensor results in temporal and spatial correlations that persist up to microseconds and for intermolecular distances on the order of protein radii. While HI slow down the bimolecular association rate in the early stages of lipid bilayer formation, they accelerate the rate of large scale assembly of lipid aggregates. This is suggestive of an important role for HI in the self-assembly kinetics of large macromolecular complexes such as tubulin. Since HI are important, questions as to whether continuum models of HI are adequate as well as improved simulation methodologies that will make simulations of more complex cellular processes practical need to be addressed. Nevertheless, the stage is set for the molecular simulations of ever more complex subcellular processes.

The role of oxidative stress and autophagy in atherosclerosis

Atherosclerosis is a multifactorial, multistep disorder of large- and medium-sized arteries involving, in addition to age, gender and menopausal status, a complex interplay between lifestyle and genetic risk factors. Atherosclerosis usually begins with the diffusion and retention of atherogenic lipoproteins into the subendothelial space of the artery wall where they become oxidized by local enzymes and accumulate, leading to the formation of a cushion called atheroma or atheromatous or fibrofatty plaque, composed of a mixture of macrophages, lymphocytes, smooth muscle cells (SMCs), cholesterol cleft, necrotic debris, and lipid-laden foam cells. The pathogenesis of atherosclerosis still remains incompletely understood but emerging evidence suggests that it may involve multiple cellular events, including endothelial cell (EC) dysfunction, inflammation, proliferation of vascular SMCs, matrix (ECM) alteration, and neovascularization. Actually, a growing body of evidence indicates that autophagy along with the chronic and acute overproduction of reactive oxygen species (ROS) is integral to the development and progression of the disease and may represent fruitful avenues for biological investigation and for the identification of new therapeutic targets. In this review, we give an overview of ROS and autophagy in atherosclerosis as background to understand their potential role in this vascular disease.

Lycopene inhibits neointimal hyperplasia through regulating lipid metabolism and suppressing oxidative stress

The present study aimed to investigate the possible mechanism(s) through which lycopene inhibits neointimal hyperplasia in restenosis models. A total of 32 white rabbits were randomly divided into the following four groups: A sham group, a model group, a model group treated with apocynin and a model group treated with lycopene. Immunohistochemistry and transmission electron microscopy (TEM) were used to detect the carotid structures in these groups. Quantitative polymerase chain reaction (qPCR) and western blot analysis were performed to detect the mRNA and protein expression levels of the proteins involved in cell proliferation and oxidative stress, including anti‑proliferating cell nuclear antigen, extracellular signal-regulated kinase, nicotinamide adenine dinucleotide phosphate oxidase 1, hydroxymethyl glutaric acyl coenzyme A reductase, adenosine triphosphate‑binding cassette transporter A1 and human neutrophil cytochrome b light chain. Immunohistochemistry and TEM indicated that lycopene treatment significantly reduced the intima/media ratios, the accumulation of lipids and the formation of foam cells in carotid plaques in rabbit restenosis models. Furthermore, lycopene regulated the blood lipid levels and suppressed the oxidative stress in these models. In addition, qPCR and western blot analyses revealed that lycopene significantly decreased the expression levels of cell proliferation‑associated proteins, as well as proteins involved in lipid synthesis and transportation. The results suggest that lycopene may regulate lipid metabolism and suppress oxidative stress, and thus, represents a promising therapeutic against neointimal hyperplasia.

Mesoscopic modeling as a starting point for computational analyses of cystic fibrosis as a systemic disease

Probably the most prominent expectation associated with systems biology is the computational support of personalized medicine and predictive health. At least some of this anticipated support is envisioned in the form of disease simulators that will take hundreds of personalized biomarker data as input and allow the physician to explore and optimize possible treatment regimens on a computer before the best treatment is applied to the actual patient in a custom-tailored manner. The key prerequisites for such simulators are mathematical and computational models that not only manage the input data and implement the general physiological and pathological principles of organ systems but also integrate the myriads of details that affect their functionality to a significant degree. Obviously, the construction of such models is an overwhelming task that suggests the long-term development of hierarchical or telescopic approaches representing the physiology of organs and their diseases, first coarsely and over time with increased granularity. This article illustrates the rudiments of such a strategy in the context of cystic fibrosis (CF) of the lung. The starting point is a very simplistic, generic model of inflammation, which has been shown to capture the principles of infection, trauma, and sepsis surprisingly well. The adaptation of this model to CF contains as variables healthy and damaged cells, as well as different classes of interacting cytokines and infectious microbes that are affected by mucus formation, which is the hallmark symptom of the disease (Perez-Vilar and Boucher, 2004) [1]. The simple model represents the overall dynamics of the disease progression, including so-called acute pulmonary exacerbations, quite well, but of course does not provide much detail regarding the specific processes underlying the disease. In order to launch the next level of modeling with finer granularity, it is desirable to determine which components of the coarse model contribute most to the disease dynamics. The article introduces for this purpose the concept of module gains or ModGains, which quantify the sensitivity of key disease variables in the higher-level system. In reality, these variables represent complex modules at the next level of granularity, and the computation of ModGains therefore allows an importance ranking of variables that should be replaced with more detailed models. The "hot-swapping" of such detailed modules for former variables is greatly facilitated by the architecture and implementation of the overarching, coarse model structure, which is here formulated with methods of biochemical systems theory (BST). This article is part of a Special Issue entitled: Computational Proteomics, Systems Biology & Clinical Implications. Guest Editor: Yudong Cai.