The ubiquitin-proteasome system and inflammatory activity in diabetic atherosclerotic plaques: effects of rosiglitazone treatment

Melatonin inhibits the formation of intraplaque neovessels in ApoE-/- mice via PPARγ- RhoA-ROCK pathway

BACKGROUND

According to former research, the atherosclerotic plaque is thought to be aggravated by intraplaque neovessels (IPN) and intraplaque hemorrhage (IPH). Intriguingly, a lower incidence of IPH was found in plaque treated with melatonin. In this study, we attempted to investigate the impact and underlying mechanism regarding the influences of melatonin upon IPN.

METHODS

A mouse model was established by subjecting the high fat diet (HFD)-fed ApoE-/- mice to tandem stenosis (TS) surgery with melatonin and GW9662, a PPARγ antagonist, being given by gavage. In vitro experiment was conducted with HUVECs exposing to according treatments of VEGF, melatonin, GW9662, or Y27632.

RESULTS

Plaque and IPN were attenuated by treatment with melatonin, which was then reversed by blocking PPARγ. Western blotting results showed that melatonin increased PPARγ and decreased RhoA/ROCK signaling in carotid artery. Elevated RhoA/ROCK signaling was observed in melatonin-treated mice when PPARγ was blocked. In accordance with it, experiments using protein and mRNA from HUVECs revealed that melatonin inhibited the RhoA/ROCK signaling by enhancing PPARγ. According to in vitro study, melatonin was able to inhibit cell migration and angiogenesis, which was aborted by GW9662. Blockage of ROCK using Y27632 was able to cease the effect of GW9662 and restored the suppression on cell migration and angiogenesis by melatonin.

CONCLUSIONS

Our study demonstrates that melatonin is able to curb development of plaque and IPN formation by inhibiting the migration of endothelial cells via PPARγ- RhoA-ROCK pathway. That provides a therapeutic potential for both melatonin and PPARγ agonist targeting IPN, IPH, and atherosclerotic plaque.

An examination of causal associations and shared risk factors for diabetes and cardiovascular diseases in the East Asian population: A Mendelian randomization study

BACKGROUND

One of the major contributors to disability and mortality among diabetics is cardiovascular disease (CVD), with coronary artery disease (CAD) as the most prevalent type. However, previous studies have provided controversial evidence linking diabetes to other types of CVDs, such as atrial fibrillation (AF). In addition, the risk factors that predispose people to the risk of diabetes and its complications differ across ethnicities, but the disease risk profiles in the East Asian population have been less investigated.

METHODS

The causal association between type 2 diabetes (T2D) and two types of CVDs (i.e., AF and CAD) in the East Asian population was first studied using Mendelian randomization (MR) analyses. Next, we examined the causal effect of 49 traits on T2D and CAD to identify their separate and shared risk factors in East Asians. A causal mediation analysis was performed to examine the role of T2D in mediating the relationship between the identified shared risk factors and CAD.

RESULTS

T2D was causally associated with CAD, but not AF, in East Asians. A screening of the risk factors indicated that six and 11 traits were causally associated with T2D and CAD, respectively, with suggestive levels of evidence. Alkaline phosphatase (ALP) was the only trait associated with both T2D and CAD, as revealed by the univariable MR analyses. Moreover, the causal association between ALP and CAD no longer existed after adjusting T2D as a covariable in the causal mediation study.

CONCLUSION

Our study highlights the risk profiles in the East Asian population, which is important in formulating targeted therapies for T2D and CVDs in East Asians.

Disorder in the Human Skp1 Structure is the Key to its Adaptability to Bind Many Different Proteins in the SCF Complex Assembly

Skp1(S-phase kinase-associated protein 1 - Homo sapiens) is an adapter protein of the SCF(Skp1-Cullin1-Fbox) complex, which links the constant components (Cul1-RBX) and the variable receptor (F-box proteins) in Ubiquitin E3 ligase. It is intriguing how Skp1 can recognise and bind to a variety of structurally different F-box proteins. For practical reasons, previous efforts have used truncated Skp1, and thus it has not been possible to track the crucial aspects of the substrate recognition process. In this background, we report the solution structure of the full-length Skp1 protein determined by NMR spectroscopy for the first time and investigate the sequence-dependent dynamics in the protein. The solution structure reveals that Skp1 has an architecture: β1-β2-H1-H2-L1-H3-L2-H4-H5-H6-H7(partially formed) and a long tail-like disordered C-terminus. Structural analysis using DALI (Distance Matrix Alignment) reveals conserved domain structure across species for Skp1. Backbone dynamics investigated using NMR relaxation suggest substantial variation in the motional timescales along the length of the protein. The loops and the C-terminal residues are highly flexible, and the (R2/R1) data suggests μs-ms timescale motions in the helices as well. Further, the dependence of amide proton chemical shift on temperature and curved profiles of their residuals indicate that the residues undergo transitions between native state and excited state. The curved profiles for several residues across the length of the protein suggest that there are native-like low-lying excited states, particularly for several C-terminal residues. Our results provide a rationale for how the protein can adapt itself, bind, and get functionally associated with other proteins in the SCF complex by utilising its flexibility and conformational sub-states.

Thiazolidinedione use and retinal fluid in the comparison of age-related macular degeneration treatments trials

Background

Thiazolidinediones, commonly used antidiabetic medications, have been associated with an increased risk of development of diabetic macular oedema and increased vascular endothelial cell permeability. Macular neovascularisation in age-related macular degeneration (AMD) and associated fluid leakage may be influenced by thiazolidinediones. This study aims to determine the association between thiazolidinedione usage and retinal morphological outcomes or visual acuity (VA) in patients treated with bevacizumab or ranibizumab for neovascular AMD (nAMD).

Methods

Secondary analysis of data from the Comparison of Age-related Macular Degeneration Treatments Trials. Participant self-reported diabetes status and thiazolidinedione usage at baseline. VA, intraretinal, subretinal and subretinal pigment epithelium fluid, and foveal thickness of retinal layers were evaluated at baseline and during 2-year follow-up. Comparisons of outcomes between thiazolidinedione usage groups were adjusted by macular neovascularisation lesion type in multivariable regression models.

Results

Patients taking thiazolidinedione (n=30) had lower adjusted mean VA score at baseline (difference −6.2 letters; p=0.02), greater proportion with intraretinal fluid (IRF) at year 2 (75% vs 50%, adjusted OR 2.8; p=0.04), greater mean decrease in subretinal tissue complex thickness from baseline at year 1 (difference −75.1 um; p=0.02) and greater mean decrease in subretinal thickness at year 1 (difference −41.9 um; p=0.001) and year 2 (difference −43.3 um; p=0.001).

Conclusions

In this exploratory analysis, patients with diabetes taking thiazolidinediones and treated with bevacizumab or ranibizumab for nAMD had worse baseline mean VA, greater reductions in subretinal and subretinal tissue complex thickness from baseline, and greater proportions with IRF comparing to patients not taking thiazolidinediones.

Trial registration number

ClinicalTrials.gov NCT00593450.

The Role of Peroxisome Proliferator-Activated Receptor Gamma and Atherosclerosis: Post-translational Modification and Selective Modulators

Atherosclerosis is the hallmark of cardiovascular disease (CVD) which is a leading cause of death in type 2 diabetes patients, and glycemic control is not beneficial in reducing the potential risk of CVD. Clinically, it was shown that Thiazolidinediones (TZDs), a class of peroxisome proliferator-activated receptor gamma (PPARγ) agonists, are insulin sensitizers with reducing risk of CVD, while the potential adverse effects, such as weight gain, fluid retention, bone loss, and cardiovascular risk, restricts its use in diabetic treatment. PPARγ, a ligand-activated nuclear receptor, has shown to play a crucial role in anti-atherosclerosis by promoting cholesterol efflux, repressing monocytes infiltrating into the vascular intima under endothelial layer, their transformation into macrophages, and inhibiting vascular smooth muscle cells proliferation as well as migration. The selective activation of subsets of PPARγ targets, such as through PPARγ post-translational modification, is thought to improve the safety profile of PPARγ agonists. Here, this review focuses on the significance of PPARγ activity regulation (selective activation and post-translational modification) in the occurrence, development and treatment of atherosclerosis, and further clarifies the value of PPARγ as a safe therapeutic target for anti-atherosclerosis especially in diabetic treatment.

Activated monocytes as a therapeutic target to attenuate vascular inflammation and lower cardiovascular disease-risk in patients with type 2 diabetes: A systematic review of preclinical and clinical studies

Low grade inflammation is associated with the progression of atherosclerosis. Patients with type 2 diabetes (T2D) have altered cholesterol levels, which are targeted by free radicals to promote lipid peroxidation. Elevated levels of monocyte-associated cytokines such as interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and tumor necrosis factor-alpha (TNF-α), subsequently drive endothelial tissue injury. In fact, the levels of circulating platelet-monocyte aggregates in patients with T2D is a robust marker for atherosclerosis and a cardiovascular disease (CVD)-risk factor. To identify eligible studies, we searched the major online databases using PubMed and Google Scholar. The cumulative evidence synthesized in the current review suggests that, traditional therapies which include thiazolidinediones, statins and some calcium channel blockers can be useful in the primary prevention of atherosclerosis by inhibiting the formation of monocyte-derived microparticles, and pro-inflammatory cytokines such as IL-6, TNF-α, MCP-1, and NF-κB in patients with T2D. Future studies are needed to ascertain whether the combination of dietary interventions and glucose or lipid lowering agents can provide an enhanced cardioprotection in patients with T2D.

Network Pharmacology Study on Molecular Mechanisms of Zhishi Xiebai Guizhi Decoction in the Treatment of Coronary Heart Disease

Background

Coronary heart disease is characterized by the formation of arterial plaque. If not taken seriously, it will cause serious consequences such as myocardial infarction and heart failure. Zhishi Xiebai Guizhi Decoction first appeared in “Synopsis of Prescriptions of the Golden Chamber” and is a representative prescription for the treatment of coronary heart disease. This study aims to explain the mechanism of Zhishi Xiebai Guizhi Decoction in the treatment of coronary heart disease through network pharmacology and clinical trials.

Methods

We first identified the core compounds of Zhishi Xiebai Guizhi Decoction and their potential targets through TCMSP. Then, We analyzed the molecular targets of Zhishi Xiebai Guizhi Decoction in coronary heart disease with OMIM and GeneCards databases. After the common targets were screened out, we manage to figure out the pathways of these target genes through STRING. Finally, we verify the treatment results in clinical trials.

Results

Through network pharmacology analysis, we discovered that several core compounds of Zhishi Xiebai Guizhi Decoction have anti-inflammatory effects and are of great significance to treatment of cardiovascular diseases. The mechanism may be closely related to PPARγ, inflammation, TNF signaling pathway, AMPK signaling pathway, and PI3K-Akt signaling pathway. Clinical trials have also proved the key role of inflammation.

Conclusions

Zhishi Xiebai Guizhi Decoction may play a role in treating coronary heart disease by activating PPARγ. TNF signaling pathway, AMPK signaling pathway, and PI3K-Akt signaling pathway are potential mechanisms as well. The application of network pharmacology can provide a novel method for the research of Chinese herbal medicine. We hope that Zhishi Xiebai Guizhi Decoction will be recognized as a complementary or alternative treatment for coronary heart disease.

Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders

Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.

PS-341 alleviates chronic low-grade inflammation and improves insulin sensitivity through the inhibition of TM4 (UBAC2) degradation

Background

The TM4 (UBAC2) protein, which contains 4 transmembrane domains and one ubiquitin binding domain, is mainly expressed in cell and nuclear membranes. The current research aimed to explore the role of TM4 in metabolic inflammation and to examine whether the ubiquitin–proteasome inhibitor PS-341 could regulate the function of TM4.

Methods

The metabolic phenotypes of TM4 knockout (KO) mice were studied. We next explored the association between the polymorphisms of TM4 and obesity in a Chinese Han population. TM4 expression in the visceral fat of obese patients who underwent laparoscopic cholecystectomy was also analysed. Finally, the effect of PS-341 on the degradation and function of the TM4 protein was investigated in vivo and in vitro.

Results

TM4 KO mice developed obesity, hepatosteatosis, hypertension, and glucose intolerance under a high-fat diet. TM4 counterregulated Nur77, IKKβ, and NF-kB both in vivo and in vitro. The TM4 SNP rs147851454 is significantly associated with obesity after adjusting for age and sex (OR 1.606, 95% CI 1.065–2.422 P = 0.023) in 3394 non-diabetic and 1862 type 2 diabetic adults of Han Chinese. TM4 was significantly downregulated in the visceral fat of obese patients. PS-341 induced TM4 expression through inhibition of TM4 degradation in vitro. In db/db mice, PS-341 administration led to downregulation of Nur77/IKKβ/NF-κB expression in visceral fat and liver, and alleviation of hyperglycaemia, hypertension, and glucose intolerance. The hyperinsulinaemic-euglycaemic clamp demonstrated that PS-341 improved the glucose infusion rate and alleviated insulin resistance in db/db mice.

Conclusions

PS-341 alleviates chronic low-grade inflammation and improves insulin sensitivity through inhibition of TM4 degradation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00579-8.

Chinese Herbs and Repurposing Old Drugs as Therapeutic Agents in the Regulation of Oxidative Stress and Inflammation in Pulmonary Diseases

Several pro-inflammatory factors and proteins have been characterized that are involved in the pathogenesis of inflammatory diseases, including acute respiratory distress syndrome, chronic obstructive pulmonary disease, and asthma, induced by oxidative stress, cytokines, bacterial toxins, and viruses. Reactive oxygen species (ROS) act as secondary messengers and are products of normal cellular metabolism. Under physiological conditions, ROS protect cells against oxidative stress through the maintenance of cellular redox homeostasis, which is important for proliferation, viability, cell activation, and organ function. However, overproduction of ROS is most frequently due to excessive stimulation of either the mitochondrial electron transport chain and xanthine oxidase or reduced nicotinamide adenine dinucleotide phosphate (NADPH) by pro-inflammatory cytokines, such as interleukin-1β and tumor necrosis factor α. NADPH oxidase activation and ROS overproduction could further induce numerous inflammatory target proteins that are potentially mediated via Nox/ROS-related transcription factors triggered by various intracellular signaling pathways. Thus, oxidative stress is considered important in pulmonary inflammatory processes. Previous studies have demonstrated that redox signals can induce pulmonary inflammatory diseases. Thus, therapeutic strategies directly targeting oxidative stress may be effective for pulmonary inflammatory diseases. Therefore, drugs with anti-inflammatory and anti-oxidative properties may be beneficial to these diseases. Recent studies have suggested that traditional Chinese medicines, statins, and peroxisome proliferation-activated receptor agonists could modulate inflammation-related signaling processes and may be beneficial for pulmonary inflammatory diseases. In particular, several herbal medicines have attracted attention for the management of pulmonary inflammatory diseases. Therefore, we reviewed the pharmacological effects of these drugs to dissect how they induce host defense mechanisms against oxidative injury to combat pulmonary inflammation. Moreover, the cytotoxicity of oxidative stress and apoptotic cell death can be protected via the induction of HO-1 by these drugs. The main objective of this review is to focus on Chinese herbs and old drugs to develop anti-inflammatory drugs able to induce HO-1 expression for the management of pulmonary inflammatory diseases.

The Role of Free Radicals in Autophagy Regulation: Implications for Ageing

Reactive oxygen and nitrogen species (ROS and RNS, resp.) have been traditionally perceived solely as detrimental, leading to oxidative damage of biological macromolecules and organelles, cellular demise, and ageing. However, recent data suggest that ROS/RNS also plays an integral role in intracellular signalling and redox homeostasis (redoxtasis), which are necessary for the maintenance of cellular functions. There is a complex relationship between cellular ROS/RNS content and autophagy, which represents one of the major quality control systems in the cell. In this review, we focus on redox signalling and autophagy regulation with a special interest on ageing-associated changes. In the last section, we describe the role of autophagy and redox signalling in the context of Alzheimer's disease as an example of a prevalent age-related disorder.

Thrombogenicity and central pulse pressure to enhance prediction of ischemic event occurrence in patients with established coronary artery disease: The MAGMA-ischemia score

BACKGROUND AND AIMS

Conventional cardiovascular risk estimators based on clinical demographics have limited prediction of coronary events. Markers for thrombogenicity and vascular function have not been explored in risk estimation of high-risk patients with coronary artery disease. We aimed to develop a clinical and biomarker score to predict 3-year adverse cardiovascular events.

METHODS

Four hundred eleven patients, with ejection fraction ≥40% undergoing coronary angiography, and found to have a luminal diameter stenosis ≥50%, were included in the analysis. Thrombelastography indices and central pulse pressure (CPP) were determined at the time of catheterization.

RESULTS

We identified predictors of death, myocardial infarction (MI) or stroke and developed a numerical ischemia risk score. The primary endpoint of cardiovascular death, MI or stroke occurred in 22 patients (5.4%). The factors associated with events were age, prior PCI or CABG, diabetes, CPP, and thrombin-induced platelet-fibrin clot strength, and were included in the MAGMA-ischemia score. The MAGMA-ischemia score showed a c-statistic of 0.85 (95% Confidence Interval [CI] 0.80-0.87; p<0.001) for the primary endpoint. In the subset of patients who underwent revascularization, the c-statistic was 0.90 (p<0.001). Patients with MAGMA-ischemia score greater than 5 had highest risk to develop clinical events, hazard ratio for the primary endpoint: 13.9 (95% CI 5.8-33.1, p<0.001) and for the secondary endpoint: 4.8 (95% CI 2.3-9.6, p<0.001). When compared to previous models, the MAGMA-ischemia score yielded a higher discrimination.

CONCLUSIONS

Inclusion of CPP and assessment of thrombogenicity in a novel score for patients with documented CAD enhanced the prediction of events.

Redox regulation of proteasome function

Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) were initially regarded mainly as metabolic by-products with damaging properties. Over the last decade, our understanding of their role in metabolism was drastically changed and they were recognized as essential mediators in cellular signaling cascades, as well as modulators of biochemical pathways. Proteostasis is highly affected by the various levels of intracellular and extracellular free radicals with either mild or severe outcomes. As part of the proteostatic network, the proteasome system is equally affected by redox alterations. This short review summarizes the effects of oxidative stress on proteasome status while it also recapitulates conditions and processes where redox alterations signal changes to proteasome expression, assembly and function.

Identification of Differentially Expressed Micrornas Associate with Glucose Metabolism in Different Organs of Blunt Snout Bream (Megalobrama amblycephala)

Blunt snout bream (Megalobrama amblycephala) is a widely favored herbivorous fish species and is a frequentlyused fish model for studying the metabolism physiology. This study aimed to provide a comprehensive illustration of the mechanisms of a high-starch diet (HSD) induced lipid metabolic disorder by identifying microRNAs (miRNAs) controlled pathways in glucose and lipid metabolism in fish using high-throughput sequencing technologies. Small RNA libraries derived from intestines, livers, and brains of HSD and normal-starch diet (NSD) treated M. amblycephala were sequenced and 79, 124 and 77 differentially expressed miRNAs (DEMs) in intestines, livers, and brains of HSD treated fish were identified, respectively. Bioinformatics analyses showed that these DEMs targeted hundreds of predicted genes were enriched into metabolic pathways and biosynthetic processes, including peroxisome proliferator-activated receptor (PPAR), glycolysis/gluconeogenesis, and insulin signaling pathway. These analyses confirmed that miRNAs play crucial roles in glucose and lipid metabolism related to high wheat starch treatment. These results provide information on further investigation of a DEM-related mechanism dysregulated by a high carbohydrate diet.

PPARs: regulators of metabolism and as therapeutic targets in cardiovascular disease. Part II: PPAR-β/δ and PPAR-γ

The PPARs are a subfamily of three ligand-inducible transcription factors, which belong to the superfamily of nuclear hormone receptors. In mammals, the PPAR subfamily consists of three members: PPAR-α, PPAR-β/δ and PPAR-γ. PPARs control the expression of a large number of genes involved in metabolic homeostasis, lipid, glucose and energy metabolism, adipogenesis and inflammation. PPARs regulate a large number of metabolic pathways that are implicated in the pathogenesis of metabolic diseases such as metabolic syndrome, Type 2 diabetes mellitus, nonalcoholic fatty liver disease and cardiovascular disease. The aim of this review is to provide up-to-date information about the biochemical and metabolic actions of PPAR-β/δ and PPAR-γ, the therapeutic potential of their agonists currently under clinical development and the cardiovascular disease outcome of clinical trials of PPAR-γ agonists, pioglitazone and rosiglitazone.

Nano-liquid Chromatography-orbitrap MS-based Quantitative Proteomics Reveals Differences Between the Mechanisms of Action of Carnosic Acid and Carnosol in Colon Cancer Cells

Carnosic acid (CA) and carnosol (CS) are two structurally related diterpenes present in rosemary herb (Rosmarinus officinalis). Although several studies have demonstrated that both diterpenes can scavenge free radicals and interfere in cellular processes such as cell proliferation, they may not necessarily exert the same effects at the molecular level. In this work, a shotgun proteomics study based on stable isotope dimethyl labeling (DML) and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) has been performed to identify the relative changes in proteins and to gain some light on the specific molecular targets and mechanisms of action of CA and CS in HT-29 colon cancer cells. Protein profiles revealed that CA and CS induce different Nrf2-mediated response. Furthermore, examination of our data revealed that each diterpene affects protein homeostasis by different mechanisms. CA treatment induces the expression of proteins involved in the unfolded protein response in a concentration dependent manner reflecting ER stress, whereas CS directly inhibits chymotrypsin-like activity of the 20S proteasome. In conclusion, the unbiased proteomics-wide method applied in the present study has demonstrated to be a powerful tool to reveal differences on the mechanisms of action of two related bioactive compounds in the same biological model.

15-Deoxy-Δ12,14-Prostaglandin J2 Modifies Components of the Proteasome and Inhibits Inflammatory Responses in Human Endothelial Cells

15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an electrophilic lipid mediator derived from PGD₂ with potent anti-inflammatory effects. These are likely to be due to the covalent modification of cellular proteins, via a reactive α,β-unsaturated carbonyl group in its cyclopentenone ring. This study was carried out to identify novel cellular target(s) for covalent modification by 15d-PGJ₂ and to investigate the anti-inflammatory effects of the prostaglandin on endothelial cells (EC). The data presented here show that 15d-PGJ₂ modifies and inhibits components of the proteasome and consequently inhibits the activation of the NF-κB pathway in response to TNF-α. This, in turn, inhibits the adhesion and migration of monocytes toward activated EC, by reducing the expression of adhesion molecules and chemokines in the EC. The effects are consistent with the covalent modification of 13 proteins in the 19S particle of the proteasome identified by mass spectrometry and the suppression of proteasome function, and were similar to the effects seen with a known proteasome inhibitor (MG132). The ubiquitin-proteasome system has been implicated in the regulation of several inflammatory processes and the observation that 15d-PGJ₂ profoundly affects the proteasome functions in human EC suggests that 15d-PGJ₂ may regulate the progression of inflammatory disorders such as atherosclerosis.

Histone H2AK119 and H2BK120 mono-ubiquitination modulate SET7/9 and SUV39H1 in type 1 diabetes-induced renal fibrosis

Hyperglycaemia-induced expression of extracellular matrix (ECM) components plays a major role in the development of diabetic nephropathy (DN). The epigenetic mechanisms that modulate ECM gene expression in DN remain unclear. Therefore, we examined the role of histone H2A and H2B monoubiquitination on epigenetic chromatin marks, such as histone H3 lysine dimethylation (H3K4Me2, H3K9Me2 and H3K79Me2) in type 1 diabetic rat kidney. Hyperglycaemia increased collagen deposition and Col1a1 gene expression. In whole kidney of diabetic animals, both H2AK119 mono-ubiquitination (H2AK119Ub) and H2BK120 mono-ubiquitination (H2BK120Ub) were found to be increased, whereas, in glomeruli of diabetic animals, expression of both H2AK119Ub and H2BK120Ub was reduced. Changes in ubiquitin proteasome system components like increased Rnf2 (H2A-specific E3 ligase) and decreased H2A- and H2B-specific deubiquitinases (ubiquitin-specific proteases 7, 16, 21 and 22) were also observed. Globally increased levels of chromatin marks associated with active genes (H3K4Me2 and H3K79Me2) and decreased levels of repressive marks (H3K9Me2) were also observed. Hyperglycaemia also increased the protein expression of SET7/9 and decreased the expression of SUV39H1. We also showed the decreased occupancy of H2AK119Ub and H2BK120Ub on the promoters of Set7/9 and Suv39h1 in diabetic kidney. In addition, methylation marks regulated by H2AK119Ub (H3K27Me2 and H3K36Me2) and H2BK120Ub (H3K4Me2 and H3K79Me2) were also found to be altered on the promoters of Set7/9 and Suv39h1 Taken together, these results show the functional role of H2AK119Ub and H2BK120Ub in regulating histone H3K4Me2 and H3K9Me2 through modulating the expression of SET7/9 and SUV39H1 in the development of diabetic renal fibrosis.

Increased 4-hydroxy-2-nonenal-induced proteasome dysfunction is correlated with cardiac damage in streptozotocin-injected rats with isoproterenol infusion

Increase in 4-hydroxy-2-nonenal (4HNE) due to oxidative stress has been observed in a variety of cardiac diseases such as diabetic cardiomyopathy. 4HNE exerts a damaging effect in the myocardium by interfering with subcellular organelles like mitochondria by forming adducts. Therefore, we hypothesized that increased 4HNE adduct formation in the heart results in proteasome inactivation in isoproterenol (ISO)-infused type 1 diabetes mellitus (DM) rats. Eight-week-old male Sprague Dawley rats were injected with streptozotocin (STZ, 65 mg kg(-1) ). The rats were infused with ISO (5 mg kg(-1) ) for 2 weeks by mini pumps, after 8 weeks of STZ injection. We studied normal control (n = 8) and DM + ISO (n = 10) groups. Cardiac performance was assessed by echocardiography and Millar catheter at the end of the protocol at 20 weeks. Initially, we found an increase in 4HNE adducts in the hearts of the DM + ISO group. There was also a decrease in myocardial proteasomal peptidase (chymotrypsin and trypsin-like) activity. Increases in cardiomyocyte area (446 ± 32·7 vs 221 ± 10·83) (µm(2) ), per cent area of cardiac fibrosis (7·4 ± 0·7 vs 2·7 ± 0·5) and cardiac dysfunction were also found in DM + ISO (P < 0·05) relative to controls. We also found increased 4HNE adduct formation on proteasomal subunits. Furthermore, reduced aldehyde dehydrogenase 2 activity was observed in the myocardium of the DM + ISO group. Treatment with 4HNE (100 μM) for 4 h on cultured H9c2 cardiomyocytes attenuated proteasome activity. Therefore, we conclude that the 4HNE-induced decrease in proteasome activity may be involved in the cardiac pathology in STZ-injected rats infused with ISO. Copyright © 2016 John Wiley & Sons, Ltd.

Macromolecular Degradation Systems and Cardiovascular Aging

Aging-related cardiovascular diseases are a rapidly increasing problem worldwide. Cardiac aging demonstrates progressive decline of diastolic dysfunction of ventricle and increase in ventricular and arterial stiffness accompanied by increased fibrosis stimulated by angiotensin II and proinflammatory cytokines. Reactive oxygen species and multiple signaling pathways on cellular senescence play major roles in the process. Aging is also associated with an alteration in steady state of macromolecular dynamics including a dysfunction of protein synthesis and degradation. Currently, impaired macromolecular degradation is considered to be closely related to enhanced inflammation and be involved in the process and mechanism of cardiac aging. Herein, we review the role and mechanisms of the degradation system of intracellular macromolecules in the process and pathophysiology of cardiovascular aging.

Comparison of Triggering and Nontriggering Factors in ST-Segment Elevation Myocardial Infarction and Extent of Coronary Arterial Narrowing

Various physical, emotional, and extrinsic triggers have been attributed to acute coronary syndrome. Whether a correlation can be drawn between identifiable ischemic triggers and the nature of coronary artery disease (CAD) still remains unclear. In the present study, we evaluated the correlation between triggered versus nontriggered ischemic symptoms and the extent of CAD in patients with ST-segment elevation myocardial infarction (STEMI). We conducted a retrospective, single-center observational study including 1,345 consecutive patients with STEMI, treated with primary percutaneous coronary intervention. Acute physical and emotional triggers were identified in patients' historical data. Independent predictors of multivessel CAD were determined using a logistic regression model. A potential trigger was identified in 37% of patients. Physical exertion was found to be the most dominant trigger (65%) followed by psychological stress (16%) and acute illness (12%). Patients with nontriggered STEMI tended to be older and more likely to have co-morbidities. Patients with nontriggered STEMI showed a higher rate of multivessel CAD (73% vs 30%, p <0.001). In a multivariate regression model, nontriggered symptoms emerged as an independent predictor of multivessel CAD (odds ratio 8.33, 95% CI 5.74 to 12.5, p = 0.001). No specific trigger was found to predict independently the extent of CAD. In conclusion, symptoms onset without a recognizable trigger is associated with multivessel CAD in STEMI. Further studies will be required to elucidate the putative mechanisms underlying ischemic triggering.

Hypoglycemic agents and potential anti-inflammatory activity

Current literature shows an association of diabetes and secondary complications with chronic inflammation. Evidence of these immunological changes include altered levels of cytokines and chemokines, changes in the numbers and activation states of various leukocyte populations, apoptosis, and fibrosis during diabetes. Therefore, treatment of diabetes and its complications may include pharmacological strategies to reduce inflammation. Apart from anti-inflammatory drugs, various hypoglycemic agents have also been found to reduce inflammation that could contribute to improved outcomes. Extensive studies have been carried out with thiazolidinediones (peroxisome proliferator-activated receptor-γ agonist), dipeptidyl peptidase-4 inhibitors, and metformin (AMP-activated protein kinase activator) with each of these classes of compounds showing moderate-to-strong anti-inflammatory action. Sulfonylureas and alpha glucosidase inhibitors appeared to exert modest effects, while the injectable agents, insulin and glucagon-like peptide-1 receptor agonists, may improve secondary complications due to their anti-inflammatory potential. Currently, there is a lack of clinical data on anti-inflammatory effects of sodium–glucose cotransporter type 2 inhibitors. Nevertheless, for all these glucose-lowering agents, it is essential to distinguish between anti-inflammatory effects resulting from better glucose control and effects related to intrinsic anti-inflammatory actions of the pharmacological class of compounds.

AMPK/Mitochondria in Metabolic Diseases

The obtaining of nutrients is the most important task in our lives. Energy is central to life's evolutions; this was one of the aspect that induced the selection of the more adaptable and more energetically profitable species. Nowadays things have changed in our modern society. A high proportion of people has access to plenty amount of food and the obesity appear as one of the pathological characteristics of our society. Energy is obtained essentially in the mitochondria with the transfer of protons across the inner membrane that produce ATP. The exactly regulation of the synthesis and degradation of ATP (ATP ↔ ADP + phosphate) is essential to all form of life. This task is performed by the 5' adenosine monophosphate-activated protein kinase (AMPK). mtDNA is highly exposed to oxidative damage and could play a central role in human health and disease. This high potential rate of abnormalities is controlled by one of the most complex mechanism: the autophagy. AMPK appears to be the key cellular energy sensor involved in multiple cellular mechanisms and is essential to have a good metabolic homeostasis to face all the aggression and start the inflammatory reaction. Therefore its disturbances have been related with multiple diseases. Recent findings support the role of AMPK in inflammation and immunity such as Metabolic Syndrome, Obesity and Diabetes. All these Metabolic Disorders are considered pandemics and they need an adequate control and prevention. One important way to achieve it is deepen in the pathogenic mechanisms. Mitochondria and AMPK are the key elements through which it happen, their knowledge and research allow us to a better management. The discovery and use of drugs that can modulate them is imperative to improve our way of manage the metabolic disorders.

18β-Glycyrrhetinic acid exerts protective effects against cyclophosphamide-induced hepatotoxicity: potential role of PPARγ and Nrf2 upregulation

18β-Glycyrrhetinic acid (18β-GA) has been proposed as a promising hepatoprotective agent. The current study aimed to investigate the protective action and the possible mechanisms of 18β-GA against cyclophosphamide (CP)-induced liver injury in rats, focusing on the role of peroxisome proliferator-activated receptor gamma (PPARγ) and NF-E2-related factor-2 (Nrf2). Rats were administered 18β-GA at doses 25 and 50 mg/kg 2 weeks prior to CP injection. Five days after CP administration, animals were sacrificed and samples were collected. CP induced hepatic damage evidenced by the histopathological changes and significant increase in serum pro-inflammatory cytokines, liver marker enzymes, and liver lipid peroxidation and nitric oxide (NO) levels. 18β-GA counteracted CP-induced oxidative stress and inflammation as assessed by restoration of the antioxidant defenses and diminishing of pro-inflammatory cytokines, lipid peroxidation, and NO production. These hepatoprotective effects appear to depend on activation of Nrf2 and PPARγ, and subsequent suppression of nuclear factor-kappa B. In conclusion, the present study provides evidence that 18β-GA exerts hepatoprotective effects against CP through induction of antioxidant defenses and suppression of inflammatory response. This report also confers new information that 18β-GA protects liver against the toxic effect of chemotherapeutic alkylating agents via activation of Nrf2 and PPARγ.

Effects of thiazolidinedione therapy on inflammatory markers of type 2 diabetes: a meta-analysis of randomized controlled trials

BACKGROUND

Inflammation is a common feature in patients with type 2 diabetes mellitus (T2DM). This meta-analysis aimed to assess the influence of thiazolidinedione (TZD) therapy on the circulating levels of inflammatory markers in patients with T2DM.

METHODS AND RESULTS

We searched the databases Medline, Embase, ScienceDirect, Web of Science, SpringerLink, and the Cochrane Library for randomized controlled trials (RCTs) that examined the effects of thiazolidinedione vs. a placebo on patients with T2DM. The main outcomes were absolute changes in levels of circulating inflammatory markers. Twenty-seven RCTs were included and data were analyzed using a fixed-effect model or a random-effect model based on heterogeneity. Pooled results indicated that circulating levels of high-sensitivity C reactive protein (hsCRP; SMD = -0.65, 95% CI = -0.98 to -0.32, p < 0.01), monocyte chemoattractant protein-1 (MCP-1; WMD = -54.19, 95% CI = -73.86 to -34.52, p < 0.01), von Willebrand factor% (vWF%; WMD = -8.18, 95% CI = -13.54 to -2.81, p 0.01), fibrinogen (SMD = -0.26, 95% CI = -0.41 to -0.11, p < 0.01) and E-selectin(WMD = -3.57, 95% CI = -5.59 to -1.54, p <0.01) were significantly decreased after TZD therapy. However, interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), soluble CD40 ligand, plasminogen activator inhibitor 1 (PAI-1) and intercellular adhesion molecule (ICAM-1) were not significantly affected. Subgroup analyses of PAI-1, vWF% and fibrinogen in terms of trial drugs showed significant reductions for rosiglitazone (all p valuses< 0.05), but not pioglitazone treatment. Conversely, the E-selectin (p < 0.01) lowering effect only existed in the pioglitazone group. Further, rosiglitazone and pioglitazone treatment reduced serum hsCRP and MCP-1 but had no marked effects on MMP-9, IL-6 and ICAM-1.

CONCLUSIONS

Limited evidence suggested that TZD therapy had anti-inflammatory property that might contribute to its beneficial effect on inflammatory state in patients with type 2 diabetes.

Sirtuin 6 expression and inflammatory activity in diabetic atherosclerotic plaques: effects of incretin treatment

The role of sirtuin 6 (SIRT6) in atherosclerotic progression of diabetic patients is unknown. We evaluated SIRT6 expression and the effect of incretin-based therapies in carotid plaques of asymptomatic diabetic and nondiabetic patients. Plaques were obtained from 52 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Twenty-two diabetic patients were treated with drugs that work on the incretin system, GLP-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors for 26 ± 8 months before undergoing the endarterectomy. Compared with nondiabetic plaques, diabetic plaques had more inflammation and oxidative stress, along with a lesser SIRT6 expression and collagen content. Compared with non-GLP-1 therapy-treated plaques, GLP-1 therapy-treated plaques presented greater SIRT6 expression and collagen content, and less inflammation and oxidative stress, indicating a more stable plaque phenotype. These results were supported by in vitro observations on endothelial progenitor cells (EPCs) and endothelial cells (ECs). Indeed, both EPCs and ECs treated with high glucose (25 mmol/L) in the presence of GLP-1 (100 nmol/L liraglutide) presented a greater SIRT6 and lower nuclear factor-κB expression compared with cells treated only with high glucose. These findings establish the involvement of SIRT6 in the inflammatory pathways of diabetic atherosclerotic lesions and suggest its possible positive modulation by incretin, the effect of which is associated with morphological and compositional characteristics of a potential stable plaque phenotype.

Nitric oxide affects UbcH10 levels differently in type 1 and type 2 diabetic rats

BACKGROUND

Nitric oxide (NO) more effectively inhibits neointimal hyperplasia in type 2 diabetic versus nondiabetic and type 1 diabetic rodents. NO also decreases the ubiquitin-conjugating enzyme UbcH10, which is critical to cell-cycle regulation. This study seeks to determine whether UbcH10 levels in the vasculature of diabetic animal models account for the differential efficacy of NO at inhibiting neointimal hyperplasia.

MATERIALS AND METHODS

Vascular smooth muscle cells (VSMCs) harvested from nondiabetic lean Zucker (LZ) and type 2 diabetic Zucker diabetic fatty (ZDF) rats were exposed to high glucose (25 mM) and high insulin (24 nM) conditions to mimic the diabetic environment in vitro. LZ, streptozotocin-injected LZ (STZ, type 1 diabetic), and ZDF rats underwent carotid artery balloon injury (±10 mg PROLI/NO), and vessels were harvested at 3 and 14 d. UbcH10 was assessed by Western blotting and immunofluorescent staining.

RESULTS

NO more effectively reduced UbcH10 levels in LZ versus ZDF VSMCs; however, addition of insulin and glucose dramatically potentiated the inhibitory effect of NO on UbcH10 in ZDF VSMCs. Three days after balloon injury, Western blotting showed NO decreased free UbcH10 and increased polyubiquitinated UbcH10 levels by 35% in both STZ and ZDF animals. Fourteen days after injury, immunofluorescent staining showed increased UbcH10 levels throughout the arterial wall in all animal models. NO decreased UbcH10 levels in LZ and STZ rats but not in ZDF.

CONCLUSIONS

These data suggest a disconnect between UbcH10 levels and neointimal hyperplasia formation in type 2 diabetic models and contribute valuable insight regarding differential efficacy of NO in these models.

Targeting the ubiquitin-proteasome system in atherosclerosis: status quo, challenges, and perspectives

SIGNIFICANCE

Atherosclerosis is a vascular disease of worldwide significance with fatal complications such as myocardial infarction, stroke, and peripheral artery disease. Atherosclerosis is recognized as a chronic inflammatory disease leading to arterial plaque formation and vessel narrowing in different vascular beds. Besides the strong inflammatory nature of atherosclerosis, it is also characterized by proliferation, apoptosis, and enhanced oxidative stress. The ubiquitin-proteasome system (UPS) is the major intracellular degradation system in eukaryotic cells. Besides its essential role in the degradation of dysfunctional and oxidatively damaged proteins, it is involved in many processes that influence disease progression in atherosclerosis. Hence, it is logical to ask whether targeting the proteasome is a reasonable and feasible option for the treatment of atherosclerosis.

RECENT ADVANCES

Several lines of evidence suggest stage-specific dysfunction of the UPS in atherogenesis. Regulation of key processes by the proteasome in atherosclerosis, as well as the modulation of these processes by proteasome inhibitors in vascular cells, is outlined in this review. The treatment of atherosclerotic animal models with proteasome inhibitors yielded partly opposing results, the potentially underlying reasons of which are discussed here.

CRITICAL ISSUES AND FUTURE DIRECTIONS

Targeting UPS function in atherosclerosis is a promising but challenging option. Limitations of current proteasome inhibitors, dose dependency, and the cell specificity of effects, as well as the potential of future therapeutics are discussed. A stage-specific in-depth exploration of UPS function in atherosclerosis in the future will help identify targets and windows for beneficial intervention.

Enzyme enhancers for the treatment of Fabry and Pompe disease

Lysosomal storage disorders (LSD) are a group of heterogeneous diseases caused by compromised enzyme function leading to multiple organ failure. Therapeutic approaches involve enzyme replacement (ERT), which is effective for a substantial fraction of patients. However, there are still concerns about a number of issues including tissue penetrance, generation of host antibodies against the therapeutic enzyme, and financial aspects, which render this therapy suboptimal for many cases. Treatment with pharmacological chaperones (PC) was recognized as a possible alternative to ERT, because a great number of mutations do not completely abolish enzyme function, but rather trigger degradation in the endoplasmic reticulum. The theory behind PC is that they can stabilize enzymes with remaining function, avoid degradation and thereby ameliorate disease symptoms. We tested several compounds in order to identify novel small molecules that prevent premature degradation of the mutant lysosomal enzymes α-galactosidase A (for Fabry disease (FD)) and acid α-glucosidase (GAA) (for Pompe disease (PD)). We discovered that the expectorant Ambroxol when used in conjunction with known PC resulted in a significant enhancement of mutant α-galactosidase A and GAA activities. Rosiglitazone was effective on α-galactosidase A either as a monotherapy or when administered in combination with the PC 1-deoxygalactonojirimycin. We therefore propose both drugs as potential enhancers of pharmacological chaperones in FD and PD to improve current treatment strategies.

PPAR Gamma Expression Levels during Development of Heart Failure in Patients with Coronary Artery Disease after Coronary Artery Bypass-Grafting

Genetic research has elucidated molecular mechanisms of heart failure (HF). Peroxisome proliferator-activated receptors (PPARs) seem to be important in etiology of HF. The aim of study was to find the correlation between PPARγ expression during development of HF in patients and coronary artery disease (CAD) after coronary artery bypass-grafting (CABG). Methods and Results. We followed up 157 patients (mean age 63) with CAD without clinical, laboratory, or echo parameters of HF who underwent CABG. Clinical and laboratory status were assessed before CABG and at 1, 12, and 24 months. During CABG slices of aorta (Ao) and LV were collected for genetic research. HF was defined as LVEF <40% or NT-proBNP >400 pg/mL or 6MWT <400 m. Patients were divided into 2 groups: with and without HF. PPARγ expression in Ao and LV was not increased in both groups at 2-year follow-up. Sensitivity of PPARγ expression in Ao above 1.1075 in detection of HF was 20.5% (AUC 0.531, 95% CI 0.442–0.619). Positive predictive value (Ppv) was 85.7%. Sensitivity and specificity of PPARγ expression in the LV in detection of HF were 58% and 92.9%, respectively (AUC 0.540, 95% CI 0.452–0.626). Ppv was 73.2%. Conclusion. PPARγ expression in Ao and LV was comparable and should not be used as predictive factor for development of HF in patients with CAD after CABG.

Impaired proteostasis: role in the pathogenesis of diabetes mellitus

In living organisms, proteins are regularly exposed to 'molecular ageing', which corresponds to a set of non-enzymatic modifications that progressively cause irreversible damage to proteins. This phenomenon is greatly amplified under pathological conditions, such as diabetes mellitus. For their survival and optimal functioning, cells have to maintain protein homeostasis, also called 'proteostasis'. This process acts to maintain a high proportion of functional and undamaged proteins. Different mechanisms are involved in proteostasis, among them degradation systems (the main intracellular proteolytic systems being proteasome and lysosomes), folding systems (including molecular chaperones), and enzymatic mechanisms of protein repair. There is growing evidence that the disruption of proteostasis may constitute a determining event in pathophysiology. The aim of this review is to demonstrate how such a dysregulation may be involved in the pathogenesis of diabetes mellitus and in the onset of its long-term complications.

Bortezomib, a proteasome inhibitor, attenuates angiotensin II-induced hypertension and aortic remodeling in rats

Background

Hypertension is a highly prevalent disorder and a major risk factor for cardiovascular diseases. Hypertensive vascular remodeling is the pathological mal-adaption of blood vessels to the hypertensive condition that contributes to further development of high blood pressure and end-organ damage. Hypertensive remodeling involves, at least in part, changes in protein turnover. The ubiquitin proteasome system (UPS) is a major protein quality and quantity control system. This study tested the hypothesis that the proteasome inhibitor, bortezomib, would attenuate AngII-induced hypertension and its sequelae such as aortic remodeling in rats.

Methodology/Principal Findings

Male Sprague Dawley rats were subjected to AngII infusion for two weeks in the absence or presence of bortezomib. Mean arterial pressure was measured in conscious rats. Aortic tissue was collected for estimation of wall area, collagen deposition and expression of tissue inhibitors of matrix metalloproteases (TIMP), Ki67 (a marker of proliferation), reactive oxygen species (ROS) and VCAM-1 (a marker of inflammation). AngII infusion increased arterial pressure significantly (160±4 mmHg vs. vehicle treatment 133±2 mmHg). This hypertensive response was attenuated by bortezomib (138±5 mmHg). AngII hypertension was associated with significant increases in aortic wall to lumen ratio (∼29%), collagen deposition (∼14%) and expression of TIMP1 and TIMP2. AngII also increased MMP2 activity, proteasomal chymotrypsin-like activity, Ki67 staining, ROS generation and VCAM-1 immunoreactivity. Co-treatment of AngII-infused rats with bortezomib attenuated these AngII-induced responses.

Conclusions

Collectively, these data support the idea that proteasome activity contributes to AngII-induced hypertension and hypertensive aortic vascular remodeling at least in part by modulating TIMP1/2 and MMP2 function. Preliminary observations are consistent with a role for ROS, inflammatory and proliferative mechanisms in this effect. Further understanding of the mechanisms by which the proteasome is involved in hypertension and vascular structural remodeling may reveal novel targets for pharmacological treatment of hypertension, hypertensive remodeling or both.

Putative association between UBE2E2 polymorphisms and the risk of gestational diabetes mellitus

We hypothesized that ubiquitin-conjugating enzyme E2 E2 (UBE2E2) may be associated with gestational diabetes mellitus (GDM) and conducted association analyses. A total of 2071 subjects were recruited for the study, with 1104 cases and 967 controls. Two UBE2E2 single-nucleotide polymorphisms rs6780569 and rs7612463, and their haplotypes were analyzed for the study. As a result, rs7612463 showed a significant association with GDM in the recessive model. In addition, the regression analyses for the phenotypes showed that rs6780569. rs7612463 and ht2 showed significant associations with fasting plasma glucose (FPG) in recessive models, while ht1 showed an association in the dominant model. Our results show that the genetic variants of UBE2E2 are associated with GDM and FPG, which could be an important preliminary result for future studies.

Proteasome inhibitor PS-341 attenuates flow-induced pulmonary arterial hypertension

PS-341, a proteasome inhibitor, is suggested to prevent the vascular remodeling induced by high-flow pulmonary artery hypertension (PAH), but the mechanism remains unclear. The aim of the current study was to investigate the effects and possible mechanism of PS-341 on hypertension-induced vascular remodeling. Male Sprague-Dawley rats were subjected to surgical methods to produce a shunt model of PAH. Three days after the surgical procedure, the animals randomly assigned to four groups (n = 10 in each group): I: sham group; II: shunt group; III: vehicle; IV: treated group. Eight weeks postoperative, the hemodynamics data were measured through Swan-Ganz catheter; the protein expression level of proliferating cell nuclear antigen, nuclear factor-κB (NF-κB), inhibitor of nuclear factor-κB (I-κBα), transforming growth factor beta-β (TGF-β), drosophila mothers against decapentaplegic protein (Smad) and vascular endothelia growth factor (VEGF) were investigated by immunohistochemical and Western blotting; the mRNA expression level of Ubiquitin (Ub), Smad3, TGF-β1and Smad2 in lung were performed to detect by real-time reverse transcription-polymerase chain reaction analysis. The results showed that hemodynamic data and right ventricular hypertrophy were significantly improved (P < 0.05), the expression level of Ub, NF-κB, TGF-β1, Smad2 and VEGF were decreased (P < 0.05), but the level of I-κBα was increased in PS-341 treated group as compared with the shunt and vehicle groups (P < 0.05). In conclusion, the present study indicated that PS-341 could significantly improve the lung damage, attenuate pulmonary vascular remodeling induced by high blood PAH model. The mechanism may be mediated by inhibition of NF-κB and TGF-β/Smad signaling pathway and modulation the effect of VEGF.

Complex disease interventions from a network model for type 2 diabetes

There is accumulating evidence that the proteins encoded by the genes associated with a common disorder interact with each other, participate in similar pathways and share GO terms. It has been anticipated that the functional modules in a disease related functional linkage network are informative to reveal significant metabolic processes and disease's associations with other complex disorders. In the current study, Type 2 diabetes associated functional linkage network (T2DFN) containing 2770 proteins and 15041 linkages was constructed. The functional modules in this network were scored and evaluated in terms of shared pathways, co-localization, co-expression and associations with similar diseases. The assembly of top scoring overlapping members in the functional modules revealed that, along with the well known biological pathways, circadian rhythm, diverse actions of nuclear receptors in steroid and retinoic acid metabolisms have significant occurrence in the pathophysiology of the disease. The disease's association with other metabolic and neuromuscular disorders was established through shared proteins. Nuclear receptor NRIP1 has a pivotal role in lipid and carbohydrate metabolism, indicating the need to investigate subsequent effects of NRIP1 on Type 2 diabetes. Our study also revealed that CREB binding protein (CREBBP) and cardiotrophin-1 (CTF1) have suggestive roles in linking Type 2 diabetes and neuromuscular diseases.

Pioglitazone, extract of compound Danshen dripping pill, and quercetin ameliorate diabetic nephropathy in diabetic rats

BACKGROUND

Oxidative stress appears to play a role in the pathogenesis of diabetes mellitus (DM), and disruption of the ubiquitin-proteasome system may underlie these pathological changes. We tested the effect of pioglitazone (PIO), an extract of Danshen dripping pill (DSP), and quercetin (QUE) on the pathogenesis of DM in a rat model.

METHODS

Male Sprague Dawley rats were maintained in a normal control (NC) group or given a modified diet and streptozotocin (STZ) to induce DM. After STZ treatment, rats were given intragastric placebo, PIO, DSP, or QUE for 8 weeks. At the end of the treatment period, serum and urine chemistry, renal hypertrophy, renal histopathology, and renal expression of ubiquitin and nuclear factor (NF)-κB p65 were analyzed.

RESULTS

DM rats had altered body and kidney weight, altered serum and urine chemistry, increased accumulation of glomerular extracellular matrix (ECM), and increased renal expression of ubiquitin and NF-κB p65, indicating successful establishment of our DM model. Treatment with PIO, DSP, or QUE significantly ameliorated these pathological changes, although treated rats still had some symptoms of DM.

CONCLUSION

DM rats have increased expression of ubiquitin and NF-κB p65 in their renal tubules and glomeruli. PIO, DSP, and QUE ameliorated the pathological changes associated with DM and also reduced the renal expression of ubiquitin and NF-κB p65. These agents may provide protection from renal pathology associated with DM due to their anti-oxidant effects.

Medical management and strategies to prevent coronary artery disease in patients with type 2 diabetes mellitus

Coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM) is associated with increased immediate and long-term mortality compared with patients without T2DM. The amplified incidence of CAD stems partly from the aggregation of multiple risk factors, such as obesity, dyslipidemia, and hypertension, which occur in this population. In addition, there appear to be increased forces at play at the molecular and vascular levels in these individuals, which is evidenced by the increased thrombosis and inflammation that is seen in those with diabetic atherosclerosis. Hence, there is a growing need to emphasize early and vigilant risk factor management in patients with T2DM to help reduce their burden of cardiovascular-related mortality. In this article, we review the primary and secondary prevention measures as well as the management of CAD in patients with T2DM.

Enhancement of 26S proteasome functionality connects oxidative stress and vascular endothelial inflammatory response in diabetes mellitus

OBJECTIVE

Although the connection of oxidative stress and inflammation has been long recognized in diabetes mellitus, the underlying mechanisms are not fully elucidated. This study defined the role of 26S proteasomes in promoting vascular inflammatory response in early diabetes mellitus.

METHODS AND RESULTS

The 26S proteasome functionality, markers of autophagy, and unfolded protein response were assessed in (1) cultured 26S proteasome reporter cells and endothelial cells challenged with high glucose, (2) transgenic reporter (Ub(G76V)-green fluorescence protein) and wild-type (C57BL/6J) mice rendered diabetic, and (3) genetically diabetic (Akita and OVE26) mice. In glucose-challenged cells, and also in aortic, renal, and retinal tissues from diabetic mice, enhanced 26S proteasome functionality was observed, evidenced by augmentation of proteasome (chymotrypsin-like) activities and reduction in 26S proteasome reporter proteins, accompanied by increased nitrotyrosine-containing proteins. Also, whereas inhibitor of the nuclear factor κ-light-chain-enhancer of activated B cells α proteins were decreased, an increase was found in nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) nucleus translocation, which enhanced the NF-κB-mediated proinflammatory response, without affecting markers of autophagy or unfolded protein response. Importantly, the alterations were abolished by MG132 administration, small interfering RNA knockdown of PA700 (proteasome activator protein complex), or superoxide scavenging in vivo.

CONCLUSIONS

Early hyperglycemia enhances 26S proteasome functionality, not autophagy or unfolded protein response, through peroxynitrite/superoxide-mediated PA700-dependent proteasomal activation, which elevates NF- ĸB-mediated endothelial inflammatory response in early diabetes mellitus.

Rosiglitazone attenuates NF-κB-mediated Nox4 upregulation in hyperglycemia-activated endothelial cells

Vascular complications, a major cause of morbidity and mortality in diabetic patients, are related to hyperglycemia-induced oxidative stress. Previously, we reported that rosiglitazone (RSG) attenuated vascular expression and activity of NADPH oxidases in diabetic mice. The mechanisms underlying these effects remain to be elucidated. We hypothesized that RSG acts directly on endothelial cells to modulate vascular responses in diabetes. To test this hypothesis, human aortic endothelial cells (HAECs) were exposed to normal glucose (NG; 5.6 mmol/l) or high glucose (HG; 30 mmol/l) concentrations. Select HAEC monolayers were treated with RSG, caffeic acid phenethyl ester (CAPE), diphenyleneiodonium (DPI), small interfering (si)RNA (to NF-κB/p65 or Nox4), or Tempol. HG increased the expression and activity of the NADPH oxidase catalytic subunit Nox4 but not Nox1 or Nox2. RSG attenuated HG-induced NF-κB/p65 phosphorylation, nuclear translocation, and binding to the Nox4 promoter. Inhibiting NF-κB with CAPE or siNF-κB/p65 also reduced HG-induced Nox4 expression and activity. HG-induced H(2)O(2) production was attenuated by siRNA-mediated knockdown of Nox4, and HG-induced HAEC monocyte adhesion was attenuated by treatment with RSG, DPI, CAPE, or Tempol. These results indicate that HG exposure stimulates HAEC NF-κB activation, Nox4 expression, and H(2)O(2) production and that RSG attenuates HG-induced oxidative stress and subsequent monocyte-endothelial interactions by attenuating NF-κB/p65 activation and Nox4 expression. This study provides novel insights into mechanisms by which the thiazolidinedione peroxisome proliferator-activated receptor-γ ligand RSG favorably modulates endothelial responses in the diabetic vasculature.

Involvement of the ubiquitin-proteasome system in the formation of experimental postsurgical peritoneal adhesions

We investigated the Ubiquitin-Proteasome System (UPS), major nonlysosomal intracellular protein degradation system, in the genesis of experimental postsurgical peritoneal adhesions. We assayed the levels of UPS within the adhered tissue along with the development of peritoneal adhesions and used the specific UPS inhibitor bortezomib in order to assess the effect of the UPS blockade on the peritoneal adhesions. We found a number of severe postsurgical peritoneal adhesions at day 5 after surgery increasing until day 10. In the adhered tissue an increased values of ubiquitin and the 20S proteasome subunit, NFkB, IL-6, TNF-α and decreased values of IkB-beta were found. In contrast, bortezomib-treated rats showed a decreased number of peritoneal adhesions, decreased values of ubiquitin and the 20S proteasome, NFkB, IL-6, TNF-α, and increased levels of IkB-beta in the adhered peritoneal tissue. The UPS system, therefore, is primarily involved in the formation of post-surgical peritoneal adhesions in rats.

The ubiquitin-proteasome system and cardiovascular disease

Over the past decade, the role of the ubiquitin-proteasome system (UPS) has been the subject of numerous studies to elucidate its role in cardiovascular physiology and pathophysiology. There have been many advances in this field including the use of proteomics to achieve a better understanding of how the cardiac proteasome is regulated. Moreover, improved methods for the assessment of UPS function and the development of genetic models to study the role of the UPS have led to the realization that often the function of this system deviates from the norm in many cardiovascular pathologies. Hence, dysfunction has been described in atherosclerosis, familial cardiac proteinopathies, idiopathic dilated cardiomyopathies, and myocardial ischemia. This has led to numerous studies of the ubiquitin protein (E3) ligases and their roles in cardiac physiology and pathophysiology. This has also led to the controversial proposition of treating atherosclerosis, cardiac hypertrophy, and myocardial ischemia with proteasome inhibitors. Furthering our knowledge of this system may help in the development of new UPS-based therapeutic modalities for mitigation of cardiovascular disease.

PPAR-gamma in the Cardiovascular System

Peroxisome proliferator-activated receptor-γ (PPAR-γ), an essential transcriptional mediator of adipogenesis, lipid metabolism, insulin sensitivity, and glucose homeostasis, is increasingly recognized as a key player in inflammatory cells and in cardiovascular diseases (CVD) such as hypertension, cardiac hypertrophy, congestive heart failure, and atherosclerosis. PPAR-γ agonists, the thiazolidinediones (TZDs), increase insulin sensitivity, lower blood glucose, decrease circulating free fatty acids and triglycerides, lower blood pressure, reduce inflammatory markers, and reduce atherosclerosis in insulin-resistant patients and animal models. Human genetic studies on PPAR-γ have revealed that functional changes in this nuclear receptor are associated with CVD. Recent controversial clinical studies raise the question of deleterious action of PPAR-γ agonists on the cardiovascular system. These complex interactions of metabolic responsive factors and cardiovascular disease promise to be important areas of focus for the future.

Combined 3D-QSAR, molecular docking and molecular dynamics study on derivatives of peptide epoxyketone and tyropeptin-boronic acid as inhibitors against the β5 subunit of human 20S proteasome

An abnormal ubiquitin-proteasome is found in many human diseases, especially in cancer, and has received extensive attention as a promising therapeutic target in recent years. In this work, several in silico models have been built with two classes of proteasome inhibitors (PIs) by using 3D-QSAR, homology modeling, molecular docking and molecular dynamics (MD) simulations. The study resulted in two types of satisfactory 3D-QSAR models, i.e., the CoMFA model (Q(2) = 0.462, R(2) (pred) = 0.820) for epoxyketone inhibitors (EPK) and the CoMSIA model (Q(2) = 0.622, R(2) (pred) = 0.821) for tyropeptin-boronic acid derivatives (TBA). From the contour maps, some key structural factors responsible for the activity of these two series of PIs are revealed. For EPK inhibitors, the N-cap part should have higher electropositivity; a large substituent such as a benzene ring is favored at the C6-position. In terms of TBA inhibitors, hydrophobic substituents with a larger size anisole group are preferential at the C8-position; higher electropositive substituents like a naphthalene group at the C3-position can enhance the activity of the drug by providing hydrogen bond interaction with the protein target. Molecular docking disclosed that residues Thr60, Thr80, Gly106 and Ser189 play a pivotal role in maintaining the drug-target interactions, which are consistent with the contour maps. MD simulations further indicated that the binding modes of each conformation derived from docking is stable and in accord with the corresponding structure extracted from MD simulation overall. These results can offer useful theoretical references for designing more potent PIs.

Cholesterol in human atherosclerotic plaque is a marker for underlying disease state and plaque vulnerability

Background

Cholesterol deposition in arterial wall drives atherosclerosis. The key goal of this study was to examine the relationship between plaque cholesterol content and patient characteristics that typically associate with disease state and lesion vulnerability. Quantitative assays for free cholesterol, cholesteryl ester, triglyceride, and protein markers in atherosclerotic plaque were established and applied to plaque samples from multiple patients and arterial beds (Carotid and peripheral arteries; 98 lesions in total).

Results

We observed a lower cholesterol level in restenotic than primary peripheral plaque. We observed a trend toward a higher level in symptomatic than asymptomatic carotid plaque. Peripheral plaque from a group of well-managed diabetic patients displayed a weak trend of more free cholesterol deposition than plaque from non-diabetic patients. Plaque triglyceride content exhibited less difference in the same comparisons. We also measured cholesterol in multiple segments within one carotid plaque sample, and found that cholesterol content positively correlated with markers of plaque vulnerability, and negatively correlated with stability markers.

Conclusions

Our results offer important biological validation of cholesterol as a key lipid marker for plaque severity. Results also suggest cholesterol is a more sensitive plaque marker than routine histological staining for neutral lipids.