Activation of the ACE2/Angiotensin-(1-7)/Mas Receptor Axis Enhances the Reparative Function of Dysfunctional Diabetic Endothelial Progenitors

We tested the hypothesis that activation of the protective arm of the renin angiotensin system, the angiotensin-converting enzyme 2 (ACE2)/angiotensin-(1-7) [Ang-(1-7)]/Mas receptor axis, corrects the vasoreparative dysfunction typically seen in the CD34(+) cells isolated from diabetic individuals. Peripheral blood CD34(+) cells from patients with diabetes were compared with those of nondiabetic controls. Ang-(1-7) restored impaired migration and nitric oxide bioavailability/cGMP in response to stromal cell-derived factor and resulted in a decrease in NADPH oxidase activity. The survival and proliferation of CD34(+) cells from diabetic individuals were enhanced by Ang-(1-7) in a Mas/phosphatidylinositol 3-kinase (PI3K)/Akt-dependent manner. ACE2 expression was lower, and ACE2 activators xanthenone and diminazine aceturate were less effective in inducing the migration in cells from patients with diabetes compared with controls. Ang-(1-7) overexpression by lentiviral gene modification restored both the in vitro vasoreparative functions of diabetic cells and the in vivo homing efficiency to areas of ischemia. A cohort of patients who remained free of microvascular complications despite having a history of longstanding inadequate glycemic control had higher expression of ACE2/Mas mRNA than patients with diabetes with microvascular complications matched for age, sex, and glycemic control. Thus, ACE2/Ang-(1-7)\Mas pathway activation corrects existing diabetes-induced CD34(+) cell dysfunction and also confers protection from development of this dysfunction.

Androgens and estrogens stimulate ribosome biogenesis in prostate and breast cancer cells in receptor dependent manner

Ribosome biogenesis is a fundamental cellular process intimately linked to cell growth and proliferation, which is upregulated in most of cancers especially in aggressive cancers. In breast and prostate cancers steroid hormone receptor signalling is the principal stimulus for cancer growth and progression. Here we investigated the link between estrogen and androgen receptor signalling and the initial stage of ribosome biogenesis - transcription of rRNA genes. We have discovered that estrogen or androgen treatment can positively regulate rRNA synthesis in breast and prostate cancer cells respectively and that this effect is receptor dependent. This novel and interesting finding suggests a previously unidentified link between steroid hormone receptor signalling pathways and the regulation of ribosome biogenesis.

Investigation of Genetic Variation in Scavenger Receptor Class B, Member 1 (SCARB1) and Association with Serum Carotenoids

Objective: To investigate association of scavenger receptor class B, member 1 (SCARB1) genetic variants with serum carotenoid levels of lutein (L) and zeaxanthin (Z) and macular pigment optical density (MPOD).
Design: A cross-sectional study of healthy adults aged 20 to 70.
Participants: We recruited 302 participants after local advertisement.
Methods: We measured MPOD by customized heterochromatic flicker photometry. Fasting blood samples were taken for serum L and Z measurement by high-performance liquid chromatography and lipoprotein analysis by spectrophotometric assay. Forty-seven single nucleotide polymorphisms (SNPs) across SCARB1 were genotyped using Sequenom technology. Association analyses were performed using PLINK to compare allele and haplotype means, with adjustment for potential confounding and correction for multiple comparisons by permutation testing. Replication analysis was performed in the TwinsUK and Carotenoids in Age-Related Eye Disease Study (CAREDS) cohorts.
Main Outcome Measures: Odds ratios for MPOD area, serum L and Z concentrations associated with genetic variations in SCARB1 and interactions between SCARB1 and gender.
Results: After multiple regression analysis with adjustment for age, body mass index, gender, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, smoking, and dietary L and Z levels, 5 SNPs were significantly associated with serum L concentration and 1 SNP with MPOD (P<0.01). Only the association between rs11057841 and serum L withstood correction for multiple comparisons by permutation testing (P<0.01) and replicated in the TwinsUK cohort (P = 0.014). Independent replication was also observed in the CAREDS cohort with rs10846744 (P = 2×10-4), an SNP in high linkage disequilibrium with rs11057841 (r2 = 0.93). No interactions by gender were found. Haplotype analysis revealed no stronger association than obtained with single SNP analyses.
Conclusions: Our study has identified association between rs11057841 and serum L concentration (24% increase per T allele) in healthy subjects, independent of potential confounding factors. Our data supports further evaluation of the role for SCARB1 in the transport of macular pigment and the possible modulation of age-related macular degeneration risk through combating the effects of oxidative stress within the retina.
Financial Disclosure(s): Proprietary or commercial disclosures may be found after the references. Ophthalmology 2013;120:1632–1640 © 2013 by the American Academy of Ophthalmology.

Reduced soluble receptor for advanced glycation end-products (sRAGE) scavenger capacity precedes pre-eclampsia in Type 1 diabetes

Objective Increased advanced glycation end-products (AGEs) and their soluble receptors (sRAGE) have been implicated in the pathogenesis of pre-eclampsia (PE). However, this association has not been elucidated in pregnancies complicated by diabetes. We aimed to investigate the serum levels of these factors in pregnant women with Type 1 diabetes mellitus (T1DM), a condition associated with a four-fold increase in PE. Design Prospective study in women with T1DM at 12.2 ± 1.9, 21.6 ± 1.5 and 31.5 ± 1.7 weeks of gestation [mean ± standard deviation (SD); no overlap] before PE onset. Setting Antenatal clinics. Population Pregnant women with T1DM (n = 118; 26 developed PE) and healthy nondiabetic pregnant controls (n = 21). Methods Maternal serum levels of sRAGE (total circulating pool), N -(carboxymethyl)lysine (CML), hydroimidazolone (methylglyoxal-modified proteins) and total AGEs were measured by immunoassays. Main outcome measures Serum sRAGE and AGEs in pregnant women with T1DM who subsequently developed PE (DM PE+) versus those who remained normotensive (DM PE-). Results In DM PE+ versus DM PE-, sRAGE was significantly lower in the first and second trimesters, prior to the clinical manifestation of PE (P <0.05). Further, reflecting the net sRAGE scavenger capacity, sRAGE:hydroimidazolone was significantly lower in the second trimester (P <0.05) and sRAGE:AGE and sRAGE:CML tended to be lower in the first trimester (P <0.1) in women with T1DM who subsequently developed PE versus those who did not. These conclusions persisted after adjusting for prandial status, glycated haemoglobin (HbA1c), duration of diabetes, parity and mean arterial pressure as covariates. Conclusions In the early stages of pregnancy, lower circulating sRAGE levels, and the ratio of sRAGE to AGEs, may be associated with the subsequent development of PE in women with T1DM. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

Clinical and testing protocols for the analysis of epidermal growth factor receptor mutations in East Asian patients with non-small cell lung cancer:a combined clinical-molecular pathological approach

Several randomized phase III studies in advanced stage non-small cell lung cancer (NSCLC) confirmed the superior response rate and progression-free survival of using epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor as first-line therapy compared with chemotherapy in patients with activating EGFR mutations. Despite the need for EGFR mutation tests to guide first-line therapy in East Asian NSCLC, there are no current standard clinical and testing protocols.

RUNX3 acts as a tumor suppressor in breast cancer by targeting estrogen receptor α

Transcription factor RUNX3 is inactivated in a number of malignancies, including breast cancer, and is suggested to function as a tumor suppressor. How RUNX3 functions as a tumor suppressor in breast cancer remains undefined. Here, we show that about 20% of female Runx3(+/-) mice spontaneously developed ductal carcinoma at an average age of 14.5 months. Additionally, RUNX3 inhibits the estrogen-dependent proliferation and transformation potential of ERa-positive MCF-7 breast cancer cells in liquid culture and in soft agar and suppresses the tumorigenicity of MCF-7 cells in severe combined immunodeficiency mice. Furthermore, RUNX3 inhibits ERa-dependent transactivation by reducing the stability of ERa. Consistent with its ability to regulate the levels of ERa, expression of RUNX3 inversely correlates with the expression of ERa in breast cancer cell lines, human breast cancer tissues and Runx3(+/-) mouse mammary tumors. By destabilizing ERa, RUNX3 acts as a novel tumor suppressor in breast cancer.

Addressing Selective Polypharmacology of Antipsychotic Drugs Targeting the Bioaminergic Receptors through the Receptor Dynamic Conformational Ensembles

Selective polypharmacology, where a drug acts on multiple rather than single molecular targets involved in a disease, emerges to develop a structure-based system biology approach to design drugs selectively targeting a disease-active protein network. We focus on the bioaminergic receptors that belong to the group of integral membrane signalling proteins coupled to the G protein and represent targets for therapeutic agents against schizophrenia and depression. Among them, it has been shown that the serotonin (5-HT2A and 5-HT6), dopamine (D2 and D3) receptors induce a cognition-enhancing effect (group 1), while the histamine (H1) and serotonin (5-HT2C) receptors lead to metabolic side effects and the 5-HT2B serotonin receptor causes pulmonary hypertension (group 2). Thus, the problem arises to develop an approach that allows identifying drugs targeting only the disease-active receptors, i.e. group 1. The recent release of several crystal structures of the bioaminergic receptors, involving the D3 and H1 receptors provides the possibility to model the structures of all receptors and initiate a study of the structural and dynamic context of selective polypharmacology. In this work, we use molecular dynamics simulations to generate a conformational space of the receptors and subsequently characterize its binding properties applying molecular probe mapping. All-against-all comparison of the generated probe maps of the selected diverse conformations of all receptors with the Tanimoto similarity coefficient (Tc) enable to separate the receptors of group 1 from group 2. The pharmacophore built based on the Tc-selected receptor conformations, using the multiple probe maps discovers structural features that can be used to design molecules selective towards the receptors of group 1. The importance of several predicted residues to ligand selectivity is supported by the available mutagenesis and ligand structure-activity relationships studies. In addition, the Tc-selected conformations of the receptors for group 1 show good performance in isolation of known ligands from a random decoy. Our computational structure-based protocol to tackle selective polypharmacology of antipsychotic drugs could be applied for other diseases involving multiple drug targets, such as oncologic and infectious disorders.

Insulin receptor substrate-2 is expressed in kidney epithelium and up-regulated in diabetic nephropathy

Diabetic nephropathy (DN) is a progressive fibrotic condition that may lead to end-stage renal disease and kidney failure. Transforming growth factor-ß1 and bone morphogenetic protein-7 (BMP7) have been shown to induce DN-like changes in the kidney and protect the kidney from such changes, respectively. Recent data identified insulin action at the level of the nephron as a crucial factor in the development and progression of DN. Insulin requires a family of insulin receptor substrate (IRS) proteins for its physiological effects, and many reports have highlighted the role of insulin and IRS proteins in kidney physiology and disease. Here, we observed IRS2 expression predominantly in the developing and adult kidney epithelium in mouse and human. BMP7 treatment of human kidney proximal tubule epithelial cells (HK-2 cells) increases IRS2 transcription. In addition, BMP7 treatment of HK-2 cells induces an electrophoretic shift in IRS2 migration on SDS/PAGE, and increased association with phosphatidylinositol-3-kinase, probably due to increased tyrosine/serine phosphorylation. In a cohort of DN patients with a range of chronic kidney disease severity, IRS2 mRNA levels were elevated approximately ninefold, with the majority of IRS2 staining evident in the kidney tubules in DN patients. These data show that IRS2 is expressed in the kidney epithelium and may play a role in the downstream protective events triggered by BMP7 in the kidney. The specific up-regulation of IRS2 in the kidney tubules of DN patients also indicates a novel role for IRS2 as a marker and/or mediator of human DN progression.

Dietary Restriction Induced Longevity is Mediated by Nuclear Receptor NHR-62 in Caenorhabditis elegans

Dietary restriction (DR) extends lifespan in a wide variety of species, yet the underlying mechanisms are not well understood. Here we show that the C. elegans HNF4a- related nuclear hormone receptor NHR-62 is required for metabolic and physiologic responses associated with DR-induced longevity. nhr-62 mediates the longevity of eat- 2 mutants, a genetic mimetic of dietary restriction, and blunts the longevity response of DR induced by bacterial food dilution at low nutrient levels. Metabolic changes associated with DR, including decreased Oil Red O staining, increased autophagy, and changes in fatty acid composition are partly reversed by mutation of nhr-62. Expression profiles reveal that several hundred genes induced by DR depend on the activity of NHR-62, including a putative lipase required for the DR response. This study provides critical evidence that nuclear hormone receptors regulate the DR response, suggesting hormonal and metabolic control of life span.

Simulations of Biased Agonists in the β2 Adrenergic Receptor with Accelerated Molecular Dynamics

The biased agonism of the G protein-coupled receptors (GPCRs), where in addition to a traditional G protein-signalling pathway a GPCR promotes intracellular signals though ß-arrestin, is a novel paradigm in pharmacology. Biochemical and biophysical studies have suggested that a GPCR forms a distinct ensemble of conformations signalling through the G protein and ß-arrestin. Here we report on the dynamics of the ß2 adrenergic receptor bound to the ß-arrestin and G protein biased agonists and the empty receptor to further characterize the receptor conformational changes caused by biased agonists. We use conventional and accelerated molecular dynamics (aMD) simulations to explore the conformational transitions of the GPCR from the active state to the inactive state. We found that aMD simulations enable monitoring the transition within the nanosecond timescale while capturing the known microscopic characteristics of the inactive states, such as the ionic lock, the inward position of F6.44, and water clusters. Distinct conformational states are shown to be stabilized by each biased agonist. In particular, in simulations of the receptor with the ß-arrestin biased agonist, N-cyclopentylbutanepherine we observe a different pattern of motions in helix 7 when compared to simulations with the G protein biased agonist, Salbutamol that involves perturbations of the network of interactions within the NPxxY motif. Understanding the network of interactions induced by biased ligands and the subsequent receptor conformational shifts will lead to development of more efficient drugs. © 2013 American Chemical Society

Rhinovirus upregulates transient receptor potential channels in a human neuronal cell line: Implications for respiratory virus-induced cough reflex sensitivity

ABSTRACT (250 words)
BACKGROUND: The mechanism underlying respiratory virus-induced cough hypersensitivity is unknown. Up-regulation of airway neuronal receptors responsible for sensing physical and chemical stimuli is one possibility and the transient receptor potential (TRP) channel family are potential candidates. We have used an in vitro model of sensory neurones and human rhinovirus (HRV-16) to study the effect of virus infection on TRP expression.
METHODS: IMR32 neuroblastoma cells were differentiated in culture to express three TRP channels, TRPV1, TRPA1 and TRPM8. Flow cytometry and qRT-PCR were used to measure TRP channel protein and mRNA levels following inoculation with live virus, inactivated virus, virus- induced soluble factors or pelleted virus particles. Multiplex bioassay was used to determine nerve growth factor (NGF), interleukin (IL)-1ß, IL-6 and IL-8 levels in response to infection.
RESULTS: Early up-regulation of TRPA1 and TRPV1 expression occurred 2 to4 hours post infection. This was independent of replicating virus as virus induced soluble factors alone were sufficient to increase channel expression 50 and 15 fold, respectively. NGF, IL-6 and IL-8 levels, increased in infected cell supernatants, represent possible candidates. In contrast, TRPM8 expression was maximal at 48 hours (9.6 fold) and required virus replication rather than soluble factors
CONCLUSIONS We show for the first time that rhinovirus can infect neuronal cells. Furthermore, infection causes up-regulation of TRP channels by channel specific mechanisms. Increase in TRPA1 and TRPV1 levels can be mediated by soluble factors induced by infection whereas TRPM8 requires replicating virus. TRP channels may be novel therapeutic targets for controlling virus-induced cough.

Dose-dependent effects of the once-daily GLP-1 receptor agonist lixisenatide in patients with Type 2 diabetes inadequately controlled with metformin:a randomized, double-blind, placebo-controlled trial

To evaluate the dose-response relationship of lixisenatide (AVE0010), a glucagon-like peptide-1 (GLP-1) receptor agonist, in metformin-treated patients with Type 2 diabetes.

Mifepristone, a glucocorticoid receptor antagonist, produces clinical and metabolic benefits in patients with Cushing's syndrome

Cushing's syndrome (CS) is a disorder associated with significant morbidity and mortality due to prolonged exposure to high cortisol concentrations.

Sirolimus Stimulates Vascular Stem/Progenitor Cell Migration and Differentiation Into Smooth Muscle Cells via Epidermal Growth Factor Receptor/Extracellular Signal-Regulated Kinase/β-Catenin Signaling Pathway

Sirolimus-eluting stent therapy has achieved considerable success in overcoming coronary artery restenosis. However, there remain a large number of patients presenting with restenosis after the treatment, and the source of its persistence remains unclarified. Although recent evidence supports the contribution of vascular stem/progenitor cells in restenosis formation, their functional and molecular responses to sirolimus are largely unknown.