Inhibition of NF-κB prevents high glucose-induced proliferation and plasminogen activator inhibitor-1 expression in vascular smooth muscle cells

Beta arrestin-related signalling axes are influenced by dexamethasone and metformin in vascular smooth muscle cells cultured in high glucose condition

BACKGROUND

Metformin (Met) and dexamethasone (Dexa) are known to reduce blood sugar levels and anti-inflammatory effects, respectively. Based on the acceleration of atherosclerosis process in diabetes, the β-arrestin 2 (BARR2) gene and protein expression levels were evaluated in vascular smooth muscle cells (VSMCs) treated with Met and Dexa in high glucose conditions in this study.

METHODS AND MATERIALS

Human VSMCs were cultured in Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 (DMEM-F12) medium and, were treated with different values of Met (1 mM, 5 mM and 7 mM) and Dexa (10-7  M, 10-6  M and 10-5  M) in 24- and 48-h periods. The BARR2 gene and protein expression levels were identified with RT-qPCR and western blotting techniques, respectively. The signalling axes were predicted from gene network made using Cytoscape software and, were annotated with Gene Ontology.

RESULTS

The BARR2 gene and protein expression levels reduced in VSMCs treated with Dexa and Met after 24- and 48-h periods. These results were more changed after 48 h. Furthermore, many BARR2-related signalling axes were found from the network genes.

CONCLUSION

Met and Dexa suppressed the BARR2 protein and gene expression levels in the VSMCs. Moreover, the gene network suggested some the cellular signalling axes related to BARR2 that may be affected by Met and Dexa.

Diabetes-Associated Hyperglycemia Causes Rapid-Onset Ocular Surface Damage

Purpose

The metabolic alterations due to chronic hyperglycemia are well-known to cause diabetes-associated complications. Short-term hyperglycemia has also been shown to cause many acute changes, including hemodynamic alterations and osmotic, oxidative, and inflammatory stress. The present study was designed to investigate whether diabetes-associated hyperglycemia can cause rapid-onset detrimental effects on the tear film, goblet cells, and glycocalyx and can lead to activation of an inflammatory cascade or cellular stress response in the cornea.

Methods

Mouse models of type 1 and type 2 diabetes were used. Tear film volume, goblet cell number, and corneal glycocalyx area were measured on days 7, 14, and 28 after the onset of hyperglycemia. Transcriptome analysis was performed to quantify changes in 248 transcripts of genes involved in inflammatory, apoptotic, and stress response pathways.

Results

Our data demonstrate that type 1 and type 2 diabetes-associated hyperglycemia caused a significant decrease in the tear film volume, goblet cell number, and corneal glycocalyx area. The decrease in tear film and goblet cell number was noted as early as 7 days after onset of hyperglycemia. The severity of ocular surface injury was significantly more in type 1 compared to type 2 diabetes. Diabetes mellitus also caused an increase in transcripts of genes involved in the inflammatory, apoptotic, and cellular stress response pathways.

Conclusions

The results of the present study demonstrate that diabetes-associated hyperglycemia causes rapid-onset damage to the ocular surface. Thus, short-term hyperglycemia in patients with diabetes mellitus may also play an important role in causing ocular surface injury and dry eye.

The effect of metformin on the metabolism of human vascular smooth muscle cells in high glucose conditions

OBJECTIVES

Metformin is widely used in type 2 diabetic patients as an antihyperglycemic drug. The aim of this study was to investigate the effect of metformin on the metabolism of vascular smooth muscle cells in high glucose conditions.

MATERIALS AND METHODS

The vascular smooth muscle cells were cultured in DMEM F12 containing glucose as high as 25 mM. The preconditioned cells were then treated with metformin in doses of 1, 5, and 7 mM for 24 h. MTT method was used to determine cell viability. Biochemical parameters including lactate, glucose, total protein, creatinine, and triglyceride were measured in the cell culture after the treatment with metformin. Oil Red O staining method was used to stain the lipids in the cells.

RESULTS

Metformin reduced significantly (p<0.001) VSMC proliferation in a concentration-dependent manner. With the increase of glucose uptake by VSMCs, the cell lipid deposition was not changed. Other biochemical parameters such as lactate, triglyceride, total protein, and creatinine were significantly changed in the cell culture (p<0.05).

CONCLUSIONS

Metformin increased the glucose uptake impacting metabolic pathways in VSMCs. It also increased the lactate efflux and protein metabolism without the change in cellular lipid deposition in high glucose conditions.

Focal adhesion kinase-related pathways may be suppressed by metformin in vascular smooth muscle cells in high glucose conditions

Introduction

Cardiovascular diseases are known as one of the important causes of death in patients with diabetes mellitus. Metformin is used as an oral medication for reducing blood sugar. In this study, the effects of metformin were investigated on the FAK gene expression levels, pFAK protein values, cell viability and migration rate of VSMCs in high glucose conditions.

Materials and methods

The FAK gene expression levels and pFAK protein values were evaluated in VSMCs treated with different doses of metformin (1, 5 and 7 mM), based on cell viability using RT‐qPCR, western blotting and MTT techniques. The cellular migration was evaluated by scratch assay.

Results

The FAK gene expression levels reduced significantly in metformin‐treated VSMCs at 24 h and 48 h periods (p < .0008 and p < .0001, respectively). The pFAK protein values reduced significantly at 24 h (5 mM and 7 mM metformin doses) and 48 h periods (p < .001). In agreement with pFAK protein values, cellular migration reduced significantly at 24 h and 48 h periods (p < .001).

Conclusion

The results showed that metformin may suppress the proliferation and migration of VSMCs via FAK‐related pathways and may retard the progression of vessel stenosis in diabetes.

Metabolomic Analysis of Serum and Tear Samples from Patients with Obesity and Type 2 Diabetes Mellitus

Metabolomics strategies are widely used to examine obesity and type 2 diabetes (T2D). Patients with obesity (n = 31) or T2D (n = 26) and sex- and age-matched controls (n = 28) were recruited, and serum and tear samples were collected. The concentration of 23 amino acids and 10 biogenic amines in serum and tear samples was analyzed. Statistical analysis and Pearson correlation analysis along with network analysis were carried out. Compared to controls, changes in the level of 6 analytes in the obese group and of 10 analytes in the T2D group were statistically significant. For obesity, the energy generation, while for T2D, the involvement of NO synthesis and its relation to insulin signaling and inflammation, were characteristic. We found that BCAA and glutamine metabolism, urea cycle, and beta-oxidation make up crucial parts of the metabolic changes in T2D. According to our data, the retromer-mediated retrograde transport, the ethanolamine metabolism, and, consequently, the endocannabinoid signaling and phospholipid metabolism were characteristic of both conditions and can be relevant pathways to understanding and treating insulin resistance. By providing potential therapeutic targets and new starting points for mechanistic studies, our results emphasize the importance of complex data analysis procedures to better understand the pathomechanism of obesity and diabetes.

DR1 activation promotes vascular smooth muscle cell apoptosis via up-regulation of CSE/H2 S pathway in diabetic mice

The important role of hydrogen sulfide (H₂ S) as a novel gasotransmitter in inhibiting proliferation and promoting apoptosis of vascular smooth muscle cells (VSMCs) has been widely recognized. The dopamine D1 receptor (DR1), a G protein coupled receptor, inhibits atherosclerosis by suppressing VSMC proliferation. However, whether DR1 contributes to VSMC apoptosis via the induction of endogenous H₂ S in diabetic mice is unclear. Here, we found that hyperglycemia decreased the expressions of DR1 and cystathionine-γ-lyase (CSE, a key enzyme for endogenous H₂ S production) and reduced endogenous H₂ S generation in mouse arteries and cultured VSMCs. DR1 agonist SKF38393 increased DR1 and CSE expressions and stimulated endogenous H₂ S generation. Sodium hydrosulfide (NaHS, a H₂ S donor) increased CSE expressions and H₂ S generation but had no effect on DR1 expression. In addition, high glucose (HG) increased VSMC apoptosis, up-regulated IGF-1-IGF-1R and HB-EGF-EGFR, and stimulated ERK1/2 and PI3K-Akt pathways. Overexpression of DR1, the addition of SKF38393 or supply of NaHS further promoted VSMC apoptosis and down-regulated the above pathways. Knock out of CSE or the addition of the CSE inhibitor poly propylene glycol diminished the effect of SKF38393. Moreover, calmodulin (CaM) interacted with CSE in VSMCs; HG increased intracellular Ca²⁺ concentration and induced CaM expression, further strengthened the interaction of CaM with CSE in VSMCs, which were further enhanced by SKF38393. CaM inhibitor W-7, inositol 1,4,5-trisphosphate (IP₃ ) inhibitor 2-APB, or ryanodine receptor inhibitor tetracaine abolished the stimulatory effect of SKF38393 on CaM expression and intracellular Ca²⁺ concentration. Taken together, these results suggest that DR1 up-regulates CSE/H₂ S signaling by inducing the Ca²⁺ -CaM pathway followed by down-regulations of IGF-1-IGF-1R and HB-EGF-EGFR and their downstream ERK1/2 and PI3K-Akt, finally promoting the apoptosis of VSMCs in diabetic mice.

Zinc Ameliorates the Osteogenic Effects of High Glucose in Vascular Smooth Muscle Cells

In diabetic patients, medial vascular calcification is common and associated with increased cardiovascular mortality. Excessive glucose concentrations can activate the nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-kB) and trigger pro-calcific effects in vascular smooth muscle cells (VSMCs), which may actively augment vascular calcification. Zinc is able to mitigate phosphate-induced VSMC calcification. Reduced serum zinc levels have been reported in diabetes mellitus. Therefore, in this study the effects of zinc supplementation were investigated in primary human aortic VSMCs exposed to excessive glucose concentrations. Zinc treatment was found to abrogate the stimulating effects of high glucose on VSMC calcification. Furthermore, zinc was found to blunt the increased expression of osteogenic and chondrogenic markers in high glucose-treated VSMCs. High glucose exposure was shown to activate NF-kB in VSMCs, an effect that was blunted by additional zinc treatment. Zinc was further found to increase the expression of TNFα-induced protein 3 (TNFAIP3) in high glucose-treated VSMCs. The silencing of TNFAIP3 was shown to abolish the protective effects of zinc on high glucose-induced NF-kB-dependent transcriptional activation, osteogenic marker expression, and the calcification of VSMCs. Silencing of the zinc-sensing receptor G protein-coupled receptor 39 (GPR39) was shown to abolish zinc-induced TNFAIP3 expression and the effects of zinc on high glucose-induced osteogenic marker expression. These observations indicate that zinc may be a protective factor during vascular calcification in hyperglycemic conditions.

High Glucose and Advanced Glycation End Products Induce CD147-Mediated MMP Activity in Human Adipocytes

Basigin (CD147) is a transmembrane glycoprotein that regulates several physiological processes, including the production and activity of matrix metalloproteinases (MMPs). The activity of CD147 depends mainly on its glycosylation, which varies among pathophysiological conditions. However, it is unknown whether CD147 activity or its function in MMP regulation are affected by the diabetic environment, which is characterized by high glucose (HG) levels and an excess of glycation end products (AGEs). In this study, we investigated the effect of HG and AGEs on CD147 expression in human adipocytes. We also examined the mediating role of nuclear factor kappa B (NFκB) and receptor of AGE (RAGE) to this effect. Our findings show that carboxymethyl lysine and HG increased CD147 expression and glycosylation, which was accompanied by increases in MMP2 and MMP9 expression and activity, as well as upregulations of the N-acetylglucosaminyltransferase, MGAT5. These effects were abolished by NFκB and RAGE inhibition, CD147 gene silencing, and by the glycosylation inhibitor, tunicamycin. In conclusion, the current findings indicate that AGEs and HG induce CD147 expression and glycosylation in adipocytes, with possible mediation by NFκB and RAGE. One of the critical outcomes of this pathway is augmented MMP activity known to contribute to cardiovascular complications in diabetes.

Diabetes Mellitus Promotes Smooth Muscle Cell Proliferation in Mouse Ureteral Tissue through the P-ERK/P-JNK/VEGF/PKC Signaling Pathway

Background and objectives: The aim of our study was to evaluate the role of diabetes mellitus (DM) as a significant factor affecting spontaneous stone expulsion, as suggested by previous research. Materials and methods: We investigated the influence of DM on the ureter using a murine model. The mouse-model arm of this study used 20 15 -week-old mice, including 10 normal (control) mice and 10 DM mice. We measured the proximal, middle and distal ureteral smooth muscle thickness in each mouse and the differences among ureteral sections were analyzed. Mouse ureteral specimens were also analyzed via western blotting to detect relative protein expression of phosphor–extracellular signal regulated kinases (P–ERK), phosphor–C–Jun N–terminal kinase (P–JNK), vascular endothelial growth factor (VEGF), and protein kinase C (PKC), which are representative factors involved in cell regulation. Results: We observed significant hyperproliferation of ureteral smooth muscle in DM mice compared to normal mice, which may provoke reduced peristalsis. The ureteral smooth muscle of DM mice was significantly thicker than that of normal mice in all ureteral tissues: proximal (p = 0.040), mid (p = 0.010), and distal (p = 0.028). The relative protein expression of P-ERK (p = 0.005) and P–JNK (p = 0.001) was higher in the diabetic group compared to the normal group. Additionally, protein expression of VEGF (p = 0.002) and PKC (p = 0.001) were remarkably up-regulated in DM mice. Conclusions: Hyperproliferation of ureteral smooth muscle was observed in DM mice, but not in normal mice. The pathways mediated by P–ERK, P–JNK, VEGF, and PKC may play an important role in pathological ureteral conditions.

Yixintongmai Inhibits Proliferation and Migration and Promotes Apoptosis of Vascular Smooth Muscle Cells Cultured with High Glucose

Objective

This study was designed to evaluate the effects of yixintongmai on proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs) cultured with high glucose.

Methods

VSMCs of the thoracic aorta from 5- to 8-week-old male Sprague-Dawley rats were cultured with normal (4.5 mM) or high (25 mM) glucose, respectively. The concentration of yixintongmai powder at 360 μg/ml was chosen according to pre-experimental results.

Results

Yixintongmai inhibited the proliferation of VSMCs (CCK-8 assay: 0.75 ± 0.04 versus 0.98 ± 0.09 OD, P < 0.001; cell counting: 37533 ± 1861 versus 56009 ± 3779 cells/well, P < 0.001) and the expression of proliferating cell nuclear antigen (0.74 ± 0.08 fold, P < 0.001) as compared with high glucose (HG). Yixintongmai inhibited the migration of VSMCs (transwell assay: 146 ± 16 versus 265 ± 62 cells; P < 0.001), scratch wound assay (0.17 ± 0.01 fold, P < 0.001), and the expression of matrix metalloproteinases-9 (0.87 ± 0.03 fold, P < 0.001) as compared with HG. Yixintongmai decreased mitochondrial membrane potentials (0.36 ± 0.12 fold, P < 0.001) and promoted early (2.11 ± 0.20 fold, P < 0.01) and late (2.11 ± 0.28 fold, P < 0.01) apoptosis of VSMCs as compared with HG. Yixintongmai inhibited the expression of B-cell lymphoma 2 (0.83 ± 0.07 fold, P < 0.01) and stimulated the activity of cleaved-capase-3/caspase-3 (2.00 ± 0.12 fold, P < 0.05) as compared with HG. Yixintongmai inhibited reactive oxygen species generation (0.46 ± 0.03 fold, P < 0.01) and the expression of NADPH oxidase-1 (0.84 ± 0.04 fold, P < 0.001), nuclear factor-kappa B (NF-κB) p65 (0.71 ± 0.07 fold, P < 0.001), phosphorylated NF-κB p65 (0.39 ± 0.02 fold, P < 0.0001), and inhibited nuclear translocation of NF-κB p65 (0.87 ± 0.03 fold, P < 0.001) in VSMCs as compared with HG.

Conclusions

Yixintongmai inhibits the proliferation and migration and promotes the apoptosis of VSMCs cultured with HG, which suggests the potential anti-atherosclerotic effects of this traditional Chinese medicine.

Role of SGK1 in the Osteogenic Transdifferentiation and Calcification of Vascular Smooth Muscle Cells Promoted by Hyperglycemic Conditions

In diabetes mellitus, hyperglycemia promotes the osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) to enhance medial vascular calcification, a common complication strongly associated with cardiovascular disease and mortality. The mechanisms involved are, however, still poorly understood. Therefore, the present study explored the potential role of serum- and glucocorticoid-inducible kinase 1 (SGK1) during vascular calcification promoted by hyperglycemic conditions. Exposure to high-glucose conditions up-regulated the SGK1 expression in primary human aortic VSMCs. High glucose increased osteogenic marker expression and activity and, thus, promoted the osteogenic transdifferentiation of VSMCs, effects significantly suppressed by additional treatment with the SGK1 inhibitor EMD638683. Moreover, high glucose augmented the mineralization of VSMCs in the presence of calcification medium, effects again significantly reduced by SGK1 inhibition. Similarly, SGK1 knockdown blunted the high glucose-induced osteogenic transdifferentiation of VSMCs. The osteoinductive signaling promoted by high glucose required SGK1-dependent NF-kB activation. In addition, advanced glycation end products (AGEs) increased the SGK1 expression in VSMCs, and SGK1 inhibition was able to interfere with AGEs-induced osteogenic signaling. In conclusion, SGK1 is up-regulated and mediates, at least partly, the osteogenic transdifferentiation and calcification of VSMCs during hyperglycemic conditions. Thus, SGK1 inhibition may reduce the development of vascular calcification promoted by hyperglycemia in diabetes.

MiR145-5p inhibits proliferation of PMVECs via PAI-1 in experimental hepatopulmonary syndrome rat pulmonary microvascular hyperplasia

Hepatopulmonary syndrome (HPS) is a triad of advanced liver disease, intrapulmonary vasodilatation and arterial hypoxemia. Increasing evidence shows that HPS is associated with pulmonary microvascular hyperplasia. The aim of this work was to investigate the underlying mechanism of miR-145 in regulating the proliferation of pulmonary microvascular endothelial cells (PMVECs) and angiogenesis in HPS via plasminogen activator inhibitor-1 (PAI-1). To test this, morphology score and number of pulmonary microvascular were assessed in lung tissues from rats with HPS by Hematoxylin and Eosin (H&E) staining. Expression levels of PAI-1 were assessed in lung tissues from HPS rats, as well as in PMVECs treated with HPS rat serum. We also selected the putative microRNA binding site on PAI-1 by bioinformatics analysis. Then, miR145-3p and miR145-5p expression levels in the lungs and PMVECs of rats were detected by qRT-PCR because miR145-5p is a microRNA binding site on PAI-1. In addition, the effects of miR-145-5p regulation on PAI-1 were examined by upregulation and downregulation of miR-145-5p and specific lentivirus transfection was used to overexpress and knockdown PAI-1 to assess PAI-1 function on PMVECs proliferation. Our data showed that levels of PAI-1 expression in lung tissue of rats increased significantly when rats were treated with common bile duct ligation. We found that levels of miR-145-5p were frequently downregulated in HPS tissues and cell lines, and overexpression of miR-145-5p dramatically inhibited PMVECs proliferation. We further verified PAI-1 as a novel and direct target of miR-145-5p in HPS. MiR-145-5p inhibits PAI-1 synthesis and the expression changes of PAI-1 directly affect the proliferation of PMVECs. We concluded that miR-145-5p negatively regulates PMVEC proliferation through PAI-1 expression. In addition, overexpression of miR-145-5p may prove beneficial as a therapeutic strategy for HPS treatment.

Summary: Our findings provide proof of principle that microRNAs may be useful for the future development of novel therapeutic strategies in HPS.

Regulation of angiotensin II-induced B-cell lymphoma-2-associated athanogene 3 expression in vascular smooth muscle cells

Previous studies have demonstrated that angiotensin II (Ang II) is involved in the process of atherosclerosis and vascular restenosis through its proinflammatory effect. Bcl‑2‑associated athanogene 3 (BAG3) had been suggested to be associated with proliferation, migration and invasion in many types of tumor. However, the role of BAG3 among the proliferative process of vascular smooth muscle cells (VSMCs) induced by Ang II, to the best of our knowledge, remains to be investigated. The present study demonstrated that in growth‑arrested VSMCs, Ang II‑induced VSMC proliferation, accompanied by increased BAG3 mRNA and protein expression levels in a dose‑ and time‑dependent manner. BAG3 expression levels were measured in VSMCs treated in the presence or absence of Ang II. The proliferation of VSMCs was assessed using manual cell counting and Cell Counting kit‑8 assays. mRNA and protein expression levels of BAG3, Toll‑like receptor 4 (TLR4), proliferating cell nuclear antigen, nuclear factor (NF)‑κB p65, smooth muscle protein 22α and phosphorylated NF‑κB p65 were assessed by reverse transcription‑quantitative polymerase chain reaction and western blotting, respectively. In non‑transfected or scramble short hairpin RNA (shRNA)‑transfected VSMCs cells, Ang II significantly induced VSMC proliferation. However, this Ang II‑induce proliferation was attenuated when BAG3 was silenced, suggesting that inhibition of BAG3 may somehow reduce proliferation in Ang II‑induced VSMCs. Furthermore, the TLR4/NF‑κB p65 signaling pathway was involved in BAG3 gene upregulation. In conclusion, to the best of our knowledge, the present study demonstrated for the first time that inhibition of BAG3 attenuates cell proliferation. Furthermore, Ang II induced VSMCs proliferation through regulation of BAG3 expression via the TLR4/NF‑κB p65 signaling pathway.

Chicoric acid prevents PDGF-BB-induced VSMC dedifferentiation, proliferation and migration by suppressing ROS/NFκB/mTOR/P70S6K signaling cascade

Phenotypic switch of vascular smooth muscle cells (VSMCs) is characterized by increased expressions of VSMC synthetic markers and decreased levels of VSMC contractile markers, which is an important step for VSMC proliferation and migration during the development and progression of cardiovascular diseases including atherosclerosis. Chicoric acid (CA) is identified to exert powerful cardiovascular protective effects. However, little is known about the effects of CA on VSMC biology. Herein, in cultured VSMCs, we showed that pretreatment with CA dose-dependently suppressed platelet-derived growth factor type BB (PDGF-BB)-induced VSMC phenotypic alteration, proliferation and migration. Mechanistically, PDGF-BB-treated VSMCs exhibited higher mammalian target of rapamycin (mTOR) and P70S6K phosphorylation, which was attenuated by CA pretreatment, diphenyleneiodonium chloride (DPI), reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) and nuclear factor-κB (NFκB) inhibitor Bay117082. PDGF-BB-triggered ROS production and p65-NFκB activation were inhibited by CA. In addition, both NAC and DPI abolished PDGF-BB-evoked p65-NFκB nuclear translocation, phosphorylation and degradation of Inhibitor κBα (IκBα). Of note, blockade of ROS/NFκB/mTOR/P70S6K signaling cascade prevented PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration. CA treatment prevented intimal hyperplasia and vascular remodeling in rat models of carotid artery ligation in vivo. These results suggest that CA impedes PDGF-BB-induced VSMC phenotypic switching, proliferation, migration and neointima formation via inhibition of ROS/NFκB/mTOR/P70S6K signaling cascade.

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Chicoric acid attenuated PDGF-BB-evoked VSMC phenotypic transformation, proliferation and migration.

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Chicoric acid antagonized the activated ROS/NFκB/mTOR/P70S6K signaling pathway in VSMCs.

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Chicoric acid treatment prevented intimal hyperplasia in rat models of carotid artery ligation.

NF-κβ: A Potential Target in the Management of Vascular Complications of Diabetes

Diabetes is a metabolic disorder affecting large percentage of population worldwide. NF-κβ plays key role in pathogenesis of vascular complications of diabetes. Persistent hyperglycemia activates NF-κβ that triggers expression of various cytokines, chemokines and cell adhesion molecules. Over-expression of TNF-α, interleukins, TGF-β, Bcl2 and other pro-inflammatory proteins and pro-apoptotic genes by NF-κβ is key risk factor in vascular dysfunction. NF-κβ over-expression also triggers calcification of endothelial cells leading to endothelial dysfunction and further vascular complications. Inhibition of NF-κβ pro-inflammatory pathway is upcoming novel target for management of vascular complications of diabetes. Various natural and synthetic inhibitors of NF-κβ have been studied in management of diabetic complications. Recent preclinical and clinical studies validate NF-κβ as promising target in the management of vascular complications of diabetes.

Concentration‑dependent effects of paeoniflorin on proliferation and apoptosis of vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs) are an important component of arterial walls, and their dysfunction may serve an important role in the development of cardiovascular diseases, including atherosclerosis and restenosis. Paeoniflorin (PF) is a principal component of the commonly used traditional Chinese medicine, peonies. To the best of our knowledge, the effects of PF on apoptosis and proliferation of VSMCs and its underlying molecular mechanisms have not been widely reported. Therefore, the present study was designed to investigated this phenomenon. VSMCs were treated with different concentrations of PF (25, 50 and 100 µg/ml) for 12, 24 or 48 h. The data demonstrated that PF treatment not only significantly decreased cell viability and DNA synthesis but also blocked G0/G1 cell cycle progression. This effect was associated with a decreased expression of cyclin D1, cyclin E, cyclin‑dependent kinase (CDK)4 and CDK2 as well as an upregulation of p21. Notably, a significant concentration‑dependent decrease in the phosphorylation of p65 and nuclear factor of κ light polypeptide gene enhancer in B‑cells inhibitor‑α (IκBα) was observed. In addition, it was demonstrated that PF promoted the apoptosis of VSMCs, which was associated with the increased expression of caspases. In conclusion, PF inhibited the proliferation of VSMCs by downregulating proteins associated with the nuclear factor‑κB signaling pathway. Furthermore, it promoted the apoptosis of VSMCs by upregulating the expression of caspases. These results may be useful in improving the understanding of the molecular mechanisms underlying the apoptotic and anti‑proliferative effects of PF on VSMCs, and facilitate the development of novel treatments for cardiovascular diseases.

Role of β3 adrenoceptor in rat thoracic aorta contractility

To clarify the role of β₃-AR in rat thoracic aorta contractility and underlying mechanisms. BRL 37344 (BRL) was used to detect the role of β₃-AR on rat thoracic aorta. 40 rats were randomly divided into Sham control group, Sham+SR group with SR 59230A (SR) injected, chronic heart failure (CHF) control group, and CHF+SR group. The effects of SR on thoracic aorta structure, function and NF-κB expression were estimated. BRL produced relaxant effect in both endothelium-intact and endothelium-free aorta rings, which was antagonized by SR and partially by L-NAME, but not changed by Propranolol. Similar results were obtained on thoracic aorta smooth muscle of CHF rats. β₃-AR was located in both vascular smooth muscle layer and endothelial layer. After SR injection, the aorta rings in Sham+SR group showed reduced endothelium-dependent relaxation response to Ach compared with Sham control group. The aorta rings in CHF control group showed reduced endothelium-dependent relaxation to Ach, with increased endothelium-dependent relaxation in CHF+SR group. Besides, SR injection showed increased contraction to NA. Meanwhile, NF-κB expression in Sham+SR group was higher than Sham control group, with increased expression in CHF control group but decreased in CHF+SR group. Microarray screening showed 48 and 42 differentially expressed miRNAs in Sham+SR rats and CHF+SR rats respectively with 19 of them associated with NF-κB pathways. β₃-AR is expressed in rat aorta and exerts relaxant effects through NOS-dependent pathway. β₃-AR Inhibition delayed damage of vessels in development of heart failure possibly through regulation of NF-κB signaling pathway.

Gene expression profiles and signaling mechanisms in α2B-adrenoceptor-evoked proliferation of vascular smooth muscle cells

BACKGROUND

α2-adrenoceptors are important regulators of vascular tone and blood pressure. Regulation of cell proliferation is a less well investigated consequence of α2-adrenoceptor activation. We have previously shown that α2B-adrenoceptor activation stimulates proliferation of vascular smooth muscle cells (VSMCs). This may be important for blood vessel development and plasticity and for the pathology and therapeutics of cardiovascular disorders. The underlying cellular mechanisms have remained mostly unknown. This study explored pathways of regulation of gene expression and intracellular signaling related to α2B-adrenoceptor-evoked VSMC proliferation.

RESULTS

The cellular mechanisms and signaling pathways of α2B-adrenoceptor-evoked proliferation of VSMCs are complex and include redundancy. Functional enrichment analysis and pathway analysis identified differentially expressed genes associated with α2B-adrenoceptor-regulated VSMC proliferation. They included the upregulated genes Egr1, F3, Ptgs2 and Serpine1 and the downregulated genes Cx3cl1, Cav1, Rhoa, Nppb and Prrx1. The most highly upregulated gene, Lypd8, represents a novel finding in the VSMC context. Inhibitor library screening and kinase activity profiling were applied to identify kinases in the involved signaling pathways. Putative upstream kinases identified by two different screens included PKC, Raf-1, Src, the MAP kinases p38 and JNK and the receptor tyrosine kinases EGFR and HGF/HGFR. As a novel finding, the Src family kinase Lyn was also identified as a putative upstream kinase.

CONCLUSIONS

α2B-adrenoceptors may mediate their pro-proliferative effects in VSMCs by promoting the activity of bFGF and PDGF and the growth factor receptors EGFR, HGFR and VEGFR-1/2. The Src family kinase Lyn was also identified as a putative upstream kinase. Lyn is known to be expressed in VSMCs and has been identified as an important regulator of GPCR trafficking and GPCR effects on cell proliferation. Identified Ser/Thr kinases included several PKC isoforms and the β-adrenoceptor kinases 1 and 2. Cross-talk between the signaling mechanisms involved in α2B-adrenoceptor-evoked VSMC proliferation thus appears to involve PKC activation, subsequent changes in gene expression, transactivation of EGFR, and modulation of kinase activities and growth factor-mediated signaling. While many of the identified individual signals were relatively small in terms of effect size, many of them were validated by combining pathway analysis and our integrated screening approach.

Insulin promotes vascular smooth muscle cell proliferation and apoptosis via differential regulation of tumor necrosis factor-related apoptosis-inducing ligand

BACKGROUND

Insulin regulates glucose homeostasis but can also promote vascular smooth muscle (VSMC) proliferation, important in atherogenesis. Recently, we showed that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) stimulates intimal thickening via accelerated growth of VSMCs. The aim of the present study was to determine whether insulin-induced effects on VSMCs occur via TRAIL.

METHODS

Expression of TRAIL and TRAIL receptor in response to insulin and glucose was determined by polymerase chain reaction. Transcriptional activity was assessed using wild-type and site-specific mutations of the TRAIL promoter. Chromatin immunoprecipitation studies were performed. VSMC proliferation and apoptosis was measured.

RESULTS

Insulin and glucose exposure to VSMC for 24 h stimulated TRAIL mRNA expression. This was also evident at the transcriptional level. Both insulin- and glucose-inducible TRAIL transcriptional activity was blocked by dominant-negative specificity protein-1 (Sp1) overexpression. There are five functional Sp1-binding elements (Sp1-1, Sp1-2, Sp-5/6 and Sp1-7) on the TRAIL promoter. Insulin required the Sp1-1 and Sp1-2 sites, but glucose needed all Sp1-binding sites to induce transcription. Furthermore, insulin (but not glucose) was able to promote VSMC proliferation over time, associated with increased decoy receptor-2 (DcR2) expression. In contrast, chronic 5-day exposure of VSMC to 1 µg/mL insulin repressed TRAIL and DcR2 expression, and reduced Sp1 enrichment on the TRAIL promoter. This was associated with increased cell death.

CONCLUSIONS

The findings of the present study provide a new mechanistic insight into how TRAIL is regulated by insulin. This may have significant implications at different stages of diabetes-associated cardiovascular disease. Thus, TRAIL may offer a novel therapeutic solution to combat insulin-induced vascular pathologies.

Anti-atherogenic effect of trivalent chromium-loaded CPMV nanoparticles in human aortic smooth muscle cells under hyperglycemic conditions in vitro

Atherosclerosis, a major macrovascular complication associated with diabetes, poses a tremendous burden on national health care expenditure. Despite extensive efforts, cost-effective remedies are unknown. Therapies for atherosclerosis are challenged by a lack of targeted drug delivery approaches. Toward this goal, we turn to a biology-derived drug delivery system utilizing nanoparticles formed by the plant virus, Cowpea mosaic virus (CPMV). The aim herein is to investigate the anti-atherogenic potential of the beneficial mineral nutrient, trivalent chromium, loaded CPMV nanoparticles in human aortic smooth muscle cells (HASMC) under hyperglycemic conditions. A non-covalent loading protocol is established yielding CrCl3-loaded CPMV (CPMV-Cr) carrying 2000 drug molecules per particle. Using immunofluorescence microscopy, we show that CPMV-Cr is readily taken up by HASMC in vitro. In glucose (25 mM)-stimulated cells, 100 nM CPMV-Cr inhibits HASMC proliferation concomitant to attenuated proliferating cell nuclear antigen (PCNA, proliferation marker) expression. This is accompanied by attenuation in high glucose-induced phospho-p38 and pAkt expression. Moreover, CPMV-Cr inhibits the expression of pro-inflammatory cytokines, transforming growth factor-β (TGF-β) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), in glucose-stimulated HASMCs. Finally glucose-stimulated lipid uptake is remarkably abrogated by CPMV-Cr, revealed by Oil Red O staining. Together, these data provide key cellular evidence for an atheroprotective effect of CPMV-Cr in vascular smooth muscle cells (VSMC) under hyperglycemic conditions that may promote novel therapeutic ventures for diabetic atherosclerosis.

Diabetic Cardiovascular Disease Induced by Oxidative Stress

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality among patients with diabetes mellitus (DM). DM can lead to multiple cardiovascular complications, including coronary artery disease (CAD), cardiac hypertrophy, and heart failure (HF). HF represents one of the most common causes of death in patients with DM and results from DM-induced CAD and diabetic cardiomyopathy. Oxidative stress is closely associated with the pathogenesis of DM and results from overproduction of reactive oxygen species (ROS). ROS overproduction is associated with hyperglycemia and metabolic disorders, such as impaired antioxidant function in conjunction with impaired antioxidant activity. Long-term exposure to oxidative stress in DM induces chronic inflammation and fibrosis in a range of tissues, leading to formation and progression of disease states in these tissues. Indeed, markers for oxidative stress are overexpressed in patients with DM, suggesting that increased ROS may be primarily responsible for the development of diabetic complications. Therefore, an understanding of the pathophysiological mechanisms mediated by oxidative stress is crucial to the prevention and treatment of diabetes-induced CVD. The current review focuses on the relationship between diabetes-induced CVD and oxidative stress, while highlighting the latest insights into this relationship from findings on diabetic heart and vascular disease.

Subcellular proteomic approach for identifying the signaling effectors of protein kinase C-β₂ under high glucose conditions in human umbilical vein endothelial cells

The high glucose‑induced activation of protein kinase C‑β2 (PKC‑β2) has an essential role in the pathophysiology of diabetes‑associated vascular disease. In the present study, human umbilical vein endothelial cells (HUVECs) were cultured in high and normal glucose conditions prior to being infected with a recombinant adenovirus to induce the overexpression of PKC‑β2. The activity of PKC‑β2 was also decreased using a selective PKC‑β2 inhibitor. A series of two‑dimensional electrophoresis images detected ~800 spots in the nuclei, and ~600 spots in the cytosol. Following intra‑ and inter‑group cross‑matching, 38 significantly altered spots were identified as high glucose‑induced and PKC‑β2‑associated nuclear proteins. In addition to the observation that the regulation of key proteins involved in the nuclear factor (NF)‑κB signaling cascade occurred in the cytosol, various transcription factors, including peroxisome proliferator‑activated receptor δ (PPAR‑δ), were also altered in the nuclei. A human protein‑protein interaction network of potential connections of PKC‑β2‑associated proteins was constructed in the proteomics investigation using Biological General Repository for Interaction Datasets. The results indicated that PKC‑β2 may be involved in high glucose‑induced glucose and lipid crosstalk by regulating PPAR‑δ. In addition, NF‑κB inhibitor‑interacting Ras‑like protein 1 may be important in the PKC‑β2‑NF‑κB inhibitor‑NF‑κB signaling pathway in HUVECs under high‑glucose conditions.

Transcription Factor Runx2 Promotes Aortic Fibrosis and Stiffness in Type 2 Diabetes Mellitus

RATIONALE

Accelerated arterial stiffening is a major complication of diabetes mellitus with no specific therapy available to date.

OBJECTIVE

The present study investigates the role of the osteogenic transcription factor runt-related transcription factor 2 (Runx2) as a potential mediator and therapeutic target of aortic fibrosis and aortic stiffening in diabetes mellitus.

METHODS AND RESULTS

Using a murine model of type 2 diabetes mellitus (db/db mice), we identify progressive structural aortic stiffening that precedes the onset of arterial hypertension. At the same time, Runx2 is aberrantly upregulated in the medial layer of db/db aortae, as well as in thoracic aortic samples from patients with type 2 diabetes mellitus. Vascular smooth muscle cell-specific overexpression of Runx2 in transgenic mice increases expression of its target genes, Col1a1 and Col1a2, leading to medial fibrosis and aortic stiffening. Interestingly, increased Runx2 expression per se is not sufficient to induce aortic calcification. Using in vivo and in vitro approaches, we further demonstrate that expression of Runx2 in diabetes mellitus is regulated via a redox-sensitive pathway that involves a direct interaction of NF-κB with the Runx2 promoter.

CONCLUSIONS

In conclusion, this study highlights Runx2 as a previously unrecognized inducer of vascular fibrosis in the setting of diabetes mellitus, promoting arterial stiffness irrespective of calcification.

Quantitative proteomics reveals an altered cystic fibrosis in vitro bronchial epithelial secretome

Alterations in epithelial secretions and mucociliary clearance contribute to chronic bacterial infection in cystic fibrosis (CF) lung disease, but whether CF lungs are unchanged in the absence of infection remains controversial. A proteomic comparison of airway secretions from subjects with CF and control subjects shows alterations in key biological processes, including immune response and proteolytic activity, but it is unclear if these are due to mutant CF transmembrane conductance regulator (CFTR) and/or chronic infection. We hypothesized that the CF lung apical secretome is altered under constitutive conditions in the absence of inflammatory cells and pathogens. To test this, we performed quantitative proteomics of in vitro apical secretions from air-liquid interface cultures of three life-extended CF (ΔF508/ΔF508) and three non-CF human bronchial epithelial cells after labeling of CF cells by stable isotope labeling with amino acids in cell culture. Mass spectrometry analysis identified and quantitated 666 proteins across samples, of which 70 exhibited differential enrichment or depletion in CF secretions (±1.5-fold change; P < 0.05). The key molecular functions were innate immunity (24%), cytoskeleton/extracellular matrix organization (24%), and protease/antiprotease activity (17%). Oxidative proteins and classical complement pathway proteins that are altered in CF secretions in vivo were not altered in vitro. Specific differentially increased proteins-MUC5AC and MUC5B mucins, fibronectin, and matrix metalloproteinase-9-were validated by antibody-based assays. Overall, the in vitro CF secretome data are indicative of a constitutive airway epithelium with altered innate immunity, suggesting that downstream consequences of mutant CFTR set the stage for chronic inflammation and infection in CF airways.

Evaluating PAI-1 as a biomarker for stress in diving: human serum total PAI-1 is unaltered after 2 h dry exposures to 280 kPa hyperbaric air

Plasminogen activator inhibitor (PAI-1) is induced in the vasculature and secreted into the vascular lumen in response to inflammation and oxidative stress. We have previously reported a fivefold increase in plasma PAI-1 from rats exposed to 708 kPa hyperbaric air. In the current study we assess the potential of human serum total PAI-1 as a biomarker for stress in compressed air diving. Eleven recreational divers, nine males and two females, completed four 2 h hyperbaric air exposures to 280 kPa in a pressure chamber over a period of 2 weeks. The air pressure corresponds to a diving depth of 18 m in water. Serum was collected before the study and again 3 h 30 min after completion of each hyperbaric exposure. All samples were taken in the afternoon to minimize the contribution of circadian variation. The analysis revealed no change in serum total PAI-1 after hyperbaric exposures within the group of divers (P = 0.064), but significant interindividual differences persisted throughout the study (P < 0.0005). A case of decompression sickness after the third round of hyperbaric exposure did not affect PAI-1. In conclusion, compressed air exposure to 280 kPa does not affect serum total PAI-1, and significant interindividual variation in PAI-1 levels may limit its usefulness as a biomarker. This does, however, not give a complete answer regarding PAI-1 in physiologically stressful dives. Further studies with different exposures and timing are needed for that.

Analysis of factors affecting spontaneous expulsion of ureteral stones that may predict unfavorable outcomes during watchful waiting periods: What is the influence of diabetes mellitus on the ureter?

Purpose

The aim of our study was to evaluate the association of several factors with spontaneous stone expulsion, including ureteral stone characteristics (size, location, hydronephrosis, perinephric stranding), types of medications prescribed (α-blocker, low-dose steroid), and other possible demographic and health-history factors (gender, age, serum creatinine, underlying diabetes mellitus [DM], and hypertension).

Materials and Methods

A total of 366 patients with ureteral stones were enrolled. All patients underwent watchful waiting without any invasive procedures. Initial diagnoses of ureteral stones were confirmed by computed tomography scans, which were taken at approximately 1-month intervals to check for stone expulsion. Univariate and multivariate analyses were conducted to identify significant factors that contributed to stone expulsion.

Results

Among 366 patients, 335 patients (91.5%) experienced spontaneous stone passage during a mean follow-up period of 2.95±2.62 weeks. The patients were divided into two groups depending on the success of spontaneous stone passage. Univariate analyses revealed that stone location (p=0.003), stone size (p=0.021), and underlying DM (p<0.001) were significant predictors of stone passage. Multivariate analyses confirmed that stone size (p=0.010), stone location (p=0.008), and underlying DM (p=0.003) were independent predictive factors affecting stone passage.

Conclusions

Stone size, location, and underlying DM were confirmed to be significant predictive factors for spontaneous passage of ureteral stones. Urologists should consider active procedures, such as shock wave lithotripsy or ureteroscopy, rather than conservative management in patients presenting with proximally located stones, large ureteral stones, or underlying DM.

Magnesium prevents β-glycerophosphate-induced calcification in rat aortic vascular smooth muscle cells

Vascular calcification (VC), in which high serum phosphate plays a critical role, is one major problem in patients with chronic kidney disease. Clinical studies report that magnesium has a protective effect on VC. However, the studies regarding the impact of high serum magnesium on VC at a cellular level are few and require further investigation. Therefore, the present study explored the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in rat aortic vascular smooth muscle cells (RAVSMCs). In the present study, the addition of magnesium decreased calcium deposition, which was increased by BGP. Higher magnesium levels inhibited BGP-induced alkaline phosphatase (ALP) activity and decreased the expression of core-binding factor α-1 (Cbfα1). In conclusion, higher magnesium levels prevented BGP-induced calcification in RAVSMCs and inhibited the expression of Cbfα1 and ALP. Thus, magnesium is influencing the expression of Cbfα1 and ALP associated with VC and may have the potential to serve as a role for VC in clinical situations.

Glucagon-Like Peptide-1 Receptor Activation Does not Affect Re-Endothelialization but Reduces Intimal Hyperplasia via Direct Effects on Smooth Muscle Cells in a Nondiabetic Model of Arterial Injury

Diabetic patients have an increased risk of restenosis and late stent thrombosis after angioplasty, i.e. complications that are related to a defective re-endothelialization. Exendin-4, a stable glucagon-like peptide (GLP)-1 receptor agonist, has been suggested to influence the formation of intimal hyperplasia and to increase endothelial cell proliferation in vitro. Thus, the aim of this study was to investigate the mechanisms by which treatment with exendin-4 could influence re-endothelialization and intimal hyperplasia after vascular injury.

METHODS

Sprague-Dawley rats were subjected to balloon injury of the left common carotid artery and treated for 4 weeks with exendin-4 or vehicle. Intimal hyperplasia and vessel wall elasticity were monitored noninvasively by high-frequency ultrasound, and re-endothelialization was evaluated upon sacrifice using Evans blue dye.

RESULTS AND CONCLUSION

Exendin-4 selectively reduced the proliferation of smooth muscle cells (SMCs) and intimal hyperplasia in vivo without affecting the re-endothelialization process, but treatment with exendin-4 improved arterial wall elasticity. Our data also show that exendin-4 significantly decreased the proliferation and increased the apoptosis of SMCs in vitro, effects that appear to be mediated through cAMP signaling and endothelial nitric oxide synthase following GLP-1 receptor activation. Together, these effects of exendin-4 are highly desirable and may lead to an improved outcome for patients undergoing vascular interventions.

Differential regulation of human aortic smooth muscle cell proliferation by monocyte-derived macrophages from diabetic patients

Macrophage accumulation in the arterial wall and smooth muscle cell (SMC) proliferation are features of type 2 diabetes mellitus (DM) and its vascular complications. However, the effects of diabetic monocyte-derived macrophages on vascular SMC proliferation are not clearly understood. In the present study, we investigated the pro-proliferative effect of macrophages isolated from DM patients on vascular SMCs. Macrophage-conditioned media (MCM) were prepared from macrophages isolated from DM patients. DM-MCM treatment induced HASMC proliferation, decreased p21(Cip1) and p27(Kip1) expressions, and increased microRNA (miR)-17-5p and miR-221 expressions. Inhibition of either miR-17-5p or miR-221 inhibited DM-MCM-induced cell proliferation. Inhibition of miR-17-5p abolished DM-MCM-induced p21(Cip1) down-regulation; and inhibition of miR-221 attenuated the DM-MCM-induced p27(Kip1) down-regulation. Furthermore, blocking assays demonstrated that PDGF-CC in DM-MCM is the major mediators of cell proliferation in SMCs. In conclusion, our present data support the hypothesis that SMC proliferation stimulated by macrophages may play critical roles in vascular complications in DM patients and suggest a new mechanism by which arterial disease is accelerated in diabetes.

Sulforaphane reduction of testicular apoptotic cell death in diabetic mice is associated with the upregulation of Nrf2 expression and function

Diabetes-induced testicular cell death is due predominantly to oxidative stress. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important transcription factor in controlling the antioxidative system and is inducible by sulforaphane (SFN). To test whether SFN prevents diabetes-induced testicular cell death, an insulin-defective stage of type 2 diabetes (IDS-T2DM) was induced in mice. This was accomplished by feeding them a high-fat diet (HFD) for 3 mo to induce insulin resistance and then giving one intraperitoneal injection of streptozotocin to induce hyperglycemia while age-matched control mice were fed a normal diet (ND). IDS-T2DM and ND-fed control mice were then further subdivided into those with or without 4-mo SFN treatment. IDS-T2DM induced significant increases in testicular cell death presumably through receptor and mitochondrial pathways, shown by increased ratio of Bax/Bcl2 expression and cleavage of caspase-3 and caspase-8 without significant change of endoplasmic reticulum stress. Diabetes also significantly increased testicular oxidative damage and inflammation. All of these diabetic effects were significantly prevented by SFN treatment with upregulated Nrf2 expression. These results suggest that IDS-T2DM induces testicular cell death presumably through caspase-8 activation and mitochondria-mediated cell death pathways and also by significantly downregulating testicular Nrf2 expression and function. SFN upregulates testicular Nrf2 expression and its target antioxidant expression, which was associated with significant protection of the testis from IDS-T2DM-induced germ cell death.

Atorvastatin increases lipopolysaccharide-induced expression of tumour necrosis factor-α-induced protein 8-like 2 in RAW264.7 cells

RAW264.7 cells are one of the major sources of productive inflammatory biomediators, including tumour necrosis factor-α (TNF-α) and interleukin (IL)-6. TNF-α-induced protein 8-like 2 (TIPE2) is an essential negative regulator of Toll-like and T-cell receptors, and the selective expression in the immune system prevents hyper-responsiveness and maintains immune homeostasis. The aim of the present study was to investigate whether atorvastatin upregulates the expression of TIPE2 and further regulates the inflammatory response and oxidation emergency response in RAW264.7 cells. RAW264.7 cells were incubated in Dulbecco’s modified Eagle’s medium containing lipopolysaccharide (LPS) in the presence or absence of atorvastatin. Following incubation, the medium was collected and the levels of TNF-α and IL-6 were measured using an enzyme-linked immunosorbent assay. The cells were harvested, and the mRNA and protein expression levels of TIPE2, macrophage migration inhibitory factor (MIF), IκB and nuclear factor (NF-κB)-κB were analysed using quantitative polymerase chain reaction and western blotting analysis, respectively, the expression of NOS, COX-2 and HO-1 protein were essayed by western blotting analysis, NO and ROS activities were determined. The results revealed that LPS increased the mRNA and protein expression levels of TIPE2, MIF and NF-κB, as well as the production of IL-6 and TNF-α, in a dose and time dependent manner in RAW264.7 cells. Meanwhile, LPS enhanced the expression of NOS and COX-2 protein, blocked HO-1 protein expression, increased NO and PGE2 production and ROS activity in a dose dependent manner in RAW264.7 cells. Atorvastatin significantly increased LPS induced expression of TIPE2, downregulated the expression of NOS, COX-2, MIF and NF-κB and the production of PGE2, NO, IL-6 and TNF-α in a time and dose dependent manner, and increased HO-1 protein expression, reduced ROS production in a dose dependent manner. The observations indicated that atorvastatin upregulated LPS induced expression of TIPE2 and consequently inhibited MIF, NF-κB, NOS and COX-2 expression and the production of NO, PGE2, TNF-α and IL-6, increased HO-1 expression, and inhibited ROS activity in cultured RAW264.7 cells.

PI3K/p110α inhibition selectively interferes with arterial thrombosis and neointima formation, but not re-endothelialization: potential implications for drug-eluting stent design

BACKGROUND

Impaired re-endothelialization and stent thrombosis are a safety concern associated with drug-eluting stents (DES). PI3K/p110α controls cellular wound healing pathways, thereby representing an emerging drug target to modulate vascular homoeostasis after injury.

METHODS AND RESULTS

PI3K/p110α was inhibited by treatment with the small molecule inhibitor PIK75 or a specific siRNA. Arterial thrombosis, neointima formation, and re-endothelialization were studied in a murine carotid artery injury model. Proliferation and migration of human vascular smooth muscle cell (VSMC) and endothelial cell (EC) were assessed by cell number and Boyden chamber, respectively. Endothelial senescence was evaluated by the β-galactosidase assay, endothelial dysfunction by organ chambers for isometric tension. Arterial thrombus formation was delayed in mice treated with PIK75 when compared with controls. PIK75 impaired arterial expression and activity of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1); in contrast, plasma clotting and platelet aggregation did not differ. In VSMC and EC, PIK75 inhibited expression and activity of TF and PAI-1. These effects occurred at the transcriptional level via the RhoA signalling cascade and the transcription factor NFkB. Furthermore, inhibition of PI3K/p110α with PIK75 or a specific siRNA selectively impaired proliferation and migration of VSMC while sparing EC completely. Treatment with PIK75 did not induce endothelial senescence nor inhibit endothelium-dependent relaxations. In line with this observation, treatment with PIK75 selectively inhibited neointima formation without affecting re-endothelialization following vascular injury.

CONCLUSION

Following vascular injury, PI3K/p110α inhibition selectively interferes with arterial thrombosis and neointima formation, but not re-endothelialization. Hence, PI3K/p110α represents an attractive new target in DES design.

Selective Activation of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Mediates C-Reactive Protein–Evoked Endothelial Vasodilator Dysfunction in Coronary Arterioles

Rationale :

Studies in cultured endothelium implicate that lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) or Fcγ receptor II (CD32) contributes to the proatherogenic effects of C-reactive protein (CRP). However, the identity of the receptors linking to deleterious actions of CRP in vasomotor regulation remains unknown.

Objective :

We tested the hypothesis that LOX-1 contributes to adverse effects of CRP on endothelium-dependent vasomotor function in resistance arterioles.

Methods and Results :

Porcine coronary arterioles were isolated for vasoreactivity study, dihydroethidium fluorescence staining of superoxide, immunohistochemical localization of receptors, immunoprecipitation of receptor/CRP interaction, and protein blot. Intraluminal treatment of pressurized arterioles with a pathophysiological level of CRP (7 µg/mL; 60 minutes) attenuated endothelium-dependent nitric oxide–mediated and prostacyclin-mediated dilations to serotonin and arachidonic acid, respectively. LOX-1 and CD32 were detected in the endothelium of arterioles. Blockade of LOX-1 with either pharmacological antagonist κ-carrageenan or anti–LOX-1 antibody prevented the detrimental effect of CRP on vasodilator function, whereas anti-CD32 antibody treatment was ineffective. Denudation of endothelium and blockade of LOX-1 but not CD32 prevented CRP-induced elevation of superoxide in the vessel wall. CRP was coimmunoprecipitated with LOX-1 and CD32 from CRP-treated arterioles. Similarly, LOX-1 and CD32 blockade prevented CRP-induced arteriolar expression of plasminogen activator inhibitor-1, a thrombogenic protein.

Conclusions :

CRP elicits endothelium-dependent oxidative stress and compromises nitric oxide–mediated and prostacyclin-mediated vasomotor function via LOX-1 activation. In contrast, both LOX-1 and CD32 mediate plasminogen activator inhibitor-1 upregulation in arterioles by CRP. Thus, activation of LOX-1 and CD32 may contribute to vasomotor dysfunction and proatherogenic actions of CRP, respectively.

Fluridone as a new anti-inflammatory drug

Fluridone is a herbicide extensively utilized in agriculture for its documented safety in animals. Fluridone contains a 4(1H)-pyridone and a trifluoromethyl-benzene moiety, which are also present in molecules with analgesic and anti-inflammatory properties. The established absence of adverse effects of Fluridone on animals prompted us to investigate whether it could represent a new anti-inflammatory compound targeting human cells. In stimulated human monocytes, micromolar Fluridone inhibited cyclooxygenase-2 expression and the release of monocyte chemoattractant protein-1 and prostaglandin-E2, to a similar extent as Acetylsalicylic acid. Fluridone also inhibited the proliferation of aortic smooth muscle cells and reduced proliferation and cytokine release by human activated lymphocytes. The mechanism of Fluridone seems to rely on the dose-dependent inhibition of the nuclear translocation of nuclear factor-κB, a transcription factor playing a pivotal role in inflammation. Fluridone also inhibited the release from stimulated human monocytes of abscisic acid, a plant stress hormone recently discovered also in mammalian cells, where it stimulates pro-inflammatory responses. Interestingly, the mechanism of Fluridone's toxicity in plants relies on the inhibition of the enzyme phytoene desaturase, involved in the biosynthetic pathway of ß-carotene, the precursor of absciscic acid in plants. Finally, administration of Fluridone reduced peritoneal inflammation in Zymosan-treated mice. These results suggest that Fluridone could represent a new prototype of anti-inflammatory drug, also active on abscisic acid pro-inflammatory pathway.

Peroxisome proliferator-activated receptor δ agonist attenuates hepatic steatosis by anti-inflammatory mechanism

Although peroxisome proliferator receptor (PPAR)-α and PPAR-γ agonist have been developed as chemical tools to uncover biological roles for the PPARs such as lipid and carbohydrate metabolism, PPAR-δ has not been fully investigated. In this study, we examined the effects of the PPAR-δ agonist GW0742 on fatty liver changes and inflammatory markers. We investigated the effects of PPAR-δ agonist GW0742 on fatty liver changes in OLETF rats. Intrahepatic triglyceride contents and expression of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and monocyte chemo-attractant protein-1 (MCP-1) and also, PPAR-γ coactivator (PGC)-1α gene were evaluated in liver tissues of OLETF rats and HepG2 cells after GW0742 treatment. The level of TNF-α and MCP-1 was also examined in supernatant of Raw264. 7 cell culture. To address the effects of GW0742 on insulin signaling, we performed in vitro study with AML12 mouse hepatocytes. Rats treated with GW0742 (10 mg/kg/day) from 26 to 36 weeks showed improvement in fatty infiltration of the liver. In liver tissues, mRNA expressions of TNF-α, MCP-1, and PGC-1α were significantly decreased in diabetic rats treated with GW0742 compared to diabetic control rats. We also observed that GW0742 had inhibitory effects on palmitic acid-induced fatty accumulation and inflammatory markers in HepG2 and Raw264.7 cells. The expression level of Akt and IRS-1 was significantly increased by treatment with GW0742. The PPAR-δ agonist may attenuate hepatic fat accumulation through anti-inflammatory mechanism, reducing hepatic PGC-1α gene expression, and improvement of insulin signaling.

Statins suppress glucose-induced plasminogen activator inhibitor-1 expression by regulating RhoA and nuclear factor-κB activities in cardiac microvascular endothelial cells

The aim of this study was to investigate the possible proinflammatory signaling pathways involved in statin inhibition of glucose-induced plasminogen activator inhibitor-1 (PAI-1) expression in cardiac microvascular endothelial cells (CMECs). Primary rat CMECs were grown in the presence of 5.7 or 23 mmol/L glucose. PAI-1 mRNA and protein expression levels were measured by realtime polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay, respectively. A pull-down assay was performed to determine RhoA activity. IκBα protein expression was measured by Western blotting, nuclear factor (NF)-κB activation was detected by electrophoretic mobility shift assay and its transcription activity was determined by a dual luciferase reporter gene assay. PAI-1 mRNA and protein expression levels were both increased with high glucose concentrations, but they were significantly suppressed by simvastatin and atorvastatin treatment (P < 0.01) and the effects were reversed by mevalonate (100 μmol/L) and geranylgeranyl pyrophosphate (10 μmol/L) but not farnesyl pyrophosphate (10 μmol/L). Such effects were similar to those of a RhoA inhibitor, C3 exoenzyme (5 μg/mL), inhibitors of RhoA kinase (ROCK), Y-27632 (10 μmol/L) and hydroxyfasudil (10 μmol/L) and an NF-κB inhibitor, BAY 11-7082 (5 μmol/L). High glucose-induced RhoA and NF-κB activations in CMECs were both significantly inhibited by statins (P < 0.01). Simvastatin and atorvastatin equally suppress high glucose-induced PAI-1 expression. These effects of statins may occur partly by regulating the RhoA/ROCK-NF-κB pathway. The multifunctional roles of statins may be particularly beneficial for patients with metabolic syndrome.

Pioglitazone inhibits high glucose-induced synthesis of extracellular matrix by NF-κB and AP-1 pathways in rat peritoneal mesothelial cells

High glucose (HG) in peritoneal dialysates has been demonstrated to induce extracellular matrix (ECM) synthesis by peritoneal mesothelial cells (PMCs) and to contribute to peritoneal fibrosis during continuous ambulatory peritoneal dialysis (CAPD). In the present study, we investigated the effects of pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, on HG-induced ECM accumulation and the underlying mechanism in rat PMCs (RPMCs). In cultured RPMCs, HG treatment increased the expression of fibronectin (FN), collagen I and plasminogen activation inhibitor-1 (PAI-1) at the mRNA and protein levels, while it downregulated the expression of PPARγ in a time- and concentration-dependent manner. Pretreatment with pioglitazone not only decreased the expression of PAI-1 and matrix proteins (FN and collagen I), but prevented the downregulation of PPARγ in RPMCs under HG conditions. HG treatment activated the nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) pathways. In addition, the NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), and the AP-1 inhibitor, SP600125, decreased the protein levels of FN, collagen I and PAI-1, suggesting a role for the NF-κB and AP-1 pathways in the regulation of ECM accumulation induced by HG in RPMCs. Notably, we demonstrated that pretreatment with pioglitazone significantly inhibited HG-induced NF-κB and AP-1 activation. Collectively, these results suggest that pioglitazone inhibits HG-induced ECM accumulation in RPMCs by increasing PPARγ expression, and by inhibiting the NF-κB and AP-1 pathways.

B cell-associated immune profiles in patients with end-stage renal disease (ESRD)

Most of the previous studies on immune dysregulation in end-stage renal disease (ESRD) have focused on T cell immunity. We investigated B cell subpopulations in ESRD patients and the effect of hemodialysis (HD) on B cell-associated immune profiles in these patients. Forty-four ESRD [maintenance HD patients (n = 27) and pre-dialysis patients (n = 17)] and 27 healthy volunteers were included in this study. We determined the percentage of B cell subtypes, such as mature and immature B cells, memory B cells, and interleukin (IL)-10⁺ cells, as well as B cell-producing cytokines (IL-10, IL-4 and IL-21) by florescent activated cell sorting (FACS). B cell-associated gene expression was examined using real-time PCR and B cell producing cytokines (IL-10, IL-4 and IL-21) were determined using an enzyme-linked immunosorbent assay (ELISA). The percentage of total B cells and mature B cells did not differ significantly among the three groups. The percentages of memory B cells were significantly higher in the pre-dialysis group than in the HD group (P < 0.01), but the percentage of immature B cells was significantly lower in the pre-dialysis group than in the other groups. The percentages of IL-10-expressing cells that were CD19⁺ or immature B cells did not differ significantly (P > 0.05) between the two subgroups within the ESRD group, but the serum IL-10 concentration was significantly lower in the pre-dialysis group (P < 0.01). The results of this study demonstrate significantly altered B cell-associated immunity. Specifically, an imbalance of immature and memory B cells in ESRD patients was observed, with this finding predominating in pre-dialysis patients.