Autophagy Deregulation in HIV-1-Infected Cells Increases Extracellular Vesicle Release and Contributes to TLR3 Activation.

Human immunodeficiency virus type 1 (HIV-1) infection can result in HIV-associated neurocognitive disorder (HAND), a spectrum of disorders characterized by neurological impairment and chronic inflammation. Combined antiretroviral therapy (cART) has elicited a marked reduction in the number of individuals diagnosed with HAND. However, there is continual, low-level viral transcription due to the lack of a transcription inhibitor in cART regimens, which results in the accumulation of viral products within infected cells.

Longitudinal Plasma Kallikrein Levels and Their Association With the Risk of Cardiovascular Disease Outcomes in Type 1 Diabetes in DCCT/EDIC.

We determined the relationship between plasma kallikrein and cardiovascular disease (CVD) outcomes as well as major adverse cardiovascular events (MACE) in the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) cohort of type 1 diabetes (T1D). Plasma kallikrein levels were measured longitudinally in 693 subjects at DCCT baseline (1983-1989), midpoint (1988-1991), and end (1993) and at EDIC years 4-6 (1997-1999), 8-10 (2001-2003), and 11-13 (2004-2006). Cox proportional hazards regression models assessed the association between plasma kallikrein levels and the risk of CVD.

Analysis of longitudinal semicontinuous data using marginalized two-part model.

Background: Connective tissue growth factor (CTGF), is a secreted matricellular factor that has been linked to increased risk of cardiovascular disease in diabetic subjects. Despite the biological role of CTGF in diabetes, it still remains unclear how CTGF expression is regulated. In this study, we aim to identify the clinical parameters that modulate plasma CTGF levels measured longitudinally in type 1 diabetic patients over a period of 10 years.

Plasma Connective Tissue Growth Factor (CTGF/CCN2) Levels Predict Myocardial Infarction in the Veterans Affairs Diabetes Trial (VADT) Cohort.

Objective: Connective tissue growth factor (CTGF), also known as CCN2, is a potent chemotactic and extracellular matrix-inducing matricellular protein that has been implicated in progression of inflammatory and fibroproliferative disorders. An emerging role of CTGF/CCN2 is that of a prosclerotic factor implicated in the development of cardiac disease. Our objective was to determine the role of CTGF/CCN2 as a predictor of cardiovascular events in type 2 diabetes in the Veterans Affairs Diabetes Trial (VADT) cohort.

Multivariate Generalized Linear Mixed Models With Random Intercepts To Analyze Cardiovascular Risk Markers in Type-1 Diabetic Patients.

Statistical approaches tailored to analyzing longitudinal data that have multiple outcomes with different distributions are scarce. This paucity is due to the non-availability of multivariate distributions that jointly model outcomes with different distributions other than the multivariate normal. A plethora of research has been done on the specific combination of binary-Gaussian bivariate outcomes but a more general approach that allows other mixtures of distributions for multiple longitudinal outcomes has not been thoroughly demonstrated and examined.

Plasma Prekallikrein Is Associated With Carotid Intima-Media Thickness in Type 1 Diabetes.

The hypothesis that plasma prekallikrein (PK) is a risk factor for the development of vascular complications was assessed in a study using the Diabetes Control and Complications Trial (DCCT)/Epidemiology and Diabetes Interventions and Complications (EDIC) cohort of subjects with type 1 diabetes. The circulating levels of plasma PK activity were measured in the plasma of 636 subjects with type 1 diabetes (EDIC years 3-5). Common and internal carotid intima-media thickness (IMT) were measured by B-mode ultrasonography in EDIC years 1 and 6.

Inflammatory biomarkers, glycemic variability, hypoglycemia, and renal transplant outcomes: results of a randomized controlled trial.

Background: We previously reported that compared to standard glycemic control [blood glucose (BG): 70-180 mg/dL], patients randomized to intensive glycemic control (BG: 70-110 mg/dL) were at increased risk of graft rejection in renal transplantation. However, the underlying mechanisms that associate the effect of intensive glycemic control with renal transplant outcomes have not been identified.

Methods: A secondary data analysis of 93 participants (n=44 intensive, n=49 control) was conducted using data from a previous randomized controlled clinical trial.

Relationship between vitamin D status and incidence of vascular events in the Veterans Affairs Diabetes Trial.

Objective: Few studies have examined the relationship between vitamin D levels and incident cardiovascular events in large well-characterized patient cohorts. Therefore, our objective was to determine if low vitamin D levels predicted vascular complications of diabetes.

Methods: Prospective analysis of 936 veterans with type 2 diabetes (59.

Biasing the parathyroid hormone receptor: relating in vitro ligand efficacy to in vivo biological activity.

Recent advances in our understanding of the pluridimensional nature of GPCR signaling have provided new insights into how orthosteric ligands regulate receptors, and how the phenomenon of functional selectivity or ligand "bias" might be exploited in pharmaceutical design. In contrast to the predictions of simple two-state models of GPCR function, where ligands affect all aspects of GPCR signaling proportionally, current models assume that receptors exist in multiple "active" conformations that differ in their ability to couple to different downstream effectors, and that structurally distinct ligands can bias signaling by preferentially stabilizing different active states. The type 1 parathyroid hormone receptor (PTH(1)R) offers unique insight into both the opportunities and challenges of exploiting ligand bias in pharmaceutical design, not only because numerous "biased" PTH analogs have been described but also because many of them have been characterized for biological activity in vivo.

The beta-arrestin pathway-selective type 1A angiotensin receptor (AT1A) agonist [Sar1,Ile4,Ile8]angiotensin II regulates a robust G protein-independent signaling network.

The angiotensin II peptide analog [Sar(1),Ile(4),Ile(8)]AngII (SII) is a biased AT(1A) receptor agonist that stimulates receptor phosphorylation, β-arrestin recruitment, receptor internalization, and β-arrestin-dependent ERK1/2 activation without activating heterotrimeric G-proteins. To determine the scope of G-protein-independent AT(1A) receptor signaling, we performed a gel-based phosphoproteomic analysis of AngII and SII-induced signaling in HEK cells stably expressing AT(1A) receptors. A total of 34 differentially phosphorylated proteins were detected, of which 16 were unique to SII and eight to AngII stimulation.

Plasma kallikrein promotes epidermal growth factor receptor transactivation and signaling in vascular smooth muscle through direct activation of protease-activated receptors.

The kallikrein-kinin system, along with the interlocking renin-angiotensin system, is a key regulator of vascular contractility and injury response. The principal effectors of the kallikrein-kinin system are plasma and tissue kallikreins, proteases that cleave high molecular weight kininogen to produce bradykinin. Most of the cellular actions of kallikrein (KK) are thought to be mediated by bradykinin, which acts via G protein-coupled B1 and B2 bradykinin receptors on VSMCs and endothelial cells.

The adiponectin receptors AdipoR1 and AdipoR2 activate ERK1/2 through a Src/Ras-dependent pathway and stimulate cell growth.

Adiponectin is an adipocyte-derived cytokine that has attracted much attention because of its insulin-sensitizing effects in liver and skeletal muscle. Two adiponectin receptors, AdipoR1/R2, have been cloned, but relatively little is known about their intracellular signaling mechanisms. We found that full-length adiponectin rapidly and robustly activates the ERK1/2 mitogen-activated protein kinase pathway in primary vascular smooth muscle, vascular endothelial cells, and hepatocytes.

Discovery of 5-[[4-[(2,3-dimethyl-2H-indazol-6-yl)methylamino]-2-pyrimidinyl]amino]-2-methyl-benzenesulfonamide (Pazopanib), a novel and potent vascular endothelial growth factor receptor inhibitor.

Inhibition of the vascular endothelial growth factor (VEGF) signaling pathway has emerged as one of the most promising new approaches for cancer therapy. We describe herein the key steps starting from an initial screening hit leading to the discovery of pazopanib, N(4)-(2,3-dimethyl-2H-indazol-6-yl)-N(4)-methyl-N(2)-(4-methyl-3-sulfonamidophenyl)-2,4-pyrimidinediamine, a potent pan-VEGF receptor (VEGFR) inhibitor under clinical development for renal-cell cancer and other solid tumors.

Role of beta-arrestin-mediated desensitization and signaling in the control of angiotensin AT1a receptor-stimulated transcription.

Heptahelical G protein-coupled receptors employ several mechanisms to activate the ERK1/2 cascade and control gene transcription. Previous work with the angiotensin AT1a receptor has shown that G(q/11) activation leads to a rapid and transient rise in ERK1/2 activity, whereas beta-arrestin binding supports sustained ERK1/2 activation by scaffolding a Raf.MEK.

Pharmacokinetic-pharmacodynamic correlation from mouse to human with pazopanib, a multikinase angiogenesis inhibitor with potent antitumor and antiangiogenic activity.

With the development of targeted therapeutics, especially for small-molecule inhibitors, it is important to understand whether the observed in vivo efficacy correlates with the modulation of desired/intended target in vivo. We have developed a small-molecule inhibitor of all three vascular endothelial growth factor (VEGF) receptors (VEGFR), platelet-derived growth factor receptor, and c-Kit tyrosine kinases, pazopanib (GW786034), which selectively inhibits VEGF-induced endothelial cell proliferation. It has good oral exposure and inhibits angiogenesis and tumor growth in mice.

Constitutive ERK1/2 activation by a chimeric neurokinin 1 receptor-beta-arrestin1 fusion protein. Probing the composition and function of the G protein-coupled receptor "signalsome".

The beta-arrestins, a small family of G protein-coupled receptor (GPCR)-binding proteins involved in receptor desensitization, have been shown to bind extracellular signal-regulated kinases 1 and 2 (ERK1/2) and function as scaffolds for GPCR-stimulated ERK1/2 activation. To better understand the mechanism of beta-arrestin-mediated ERK1/2 activation, we compared ERK1/2 activation by the wild-type neurokinin 1 (NK1) receptor with a chimeric NK1 receptor having beta-arrestin1 fused to the receptor C terminus (NK1-betaArr1). The NK1 receptor couples to both G(s) and G(q/11), resides on the plasma membrane, and mediates rapid ERK1/2 activation and nuclear translocation in response to neurokinin A.

Discovery and evaluation of 2-anilino-5-aryloxazoles as a novel class of VEGFR2 kinase inhibitors.

A series of derivatives of 2-anilino-5-phenyloxazole (5) has been identified as inhibitors of VEGFR2 kinase. Herein we describe the structure-activity relationship (SAR) of this novel template. Optimization of both aryl rings led to very potent inhibitors at both the enzymatic and cellular levels.

Not so strange bedfellows: G-protein-coupled receptors and Src family kinases.

Src family nonreceptor tyrosine kinases are an integral component of the signal transduction apparatus employed by growth factor receptor tyrosine kinases. As such, their role in cellular growth control and malignant transformation has been the subject of intensive investigation. In contrast, classical G-protein-coupled receptor (GPCR) signaling involves activation of second messenger-regulated serine/threonine kinases or ion channels, and is primarily involved in neurotransmission and the short-term regulation of intermediary metabolism.

Antitumour efficacy of VEGFR2 tyrosine kinase inhibitor correlates with expression of VEGF and its receptor VEGFR2 in tumour models.

During the development of indazolylpyrimidines as novel and potent inhibitors of vascular endothelial growth factor (VEGF) receptor-2 (VEGFR2) tyrosine kinase, we observed that some human tumour xenografts are more sensitive to VEGFR2 kinase inhibitors than others. A better understanding of the basis for this differential response may help to identify a predictive marker that would greatly aid in the identification of a suitable patient population for treatment. One representative compound from the indazolylpyrimidine series is GW654652 that inhibited all three VEGFRs with similar potency.

Signaling in time and space: G protein-coupled receptors and mitogen-activated protein kinases.

Because of their central role in the cellular response to growth factors, assays of MAP kinase activity are commonly used in pharmaceutical screening efforts aimed at detecting chemical modifiers of growth regulatory pathways. As our understanding of the complexity of signal transduction networks expands, however, it is becoming apparent that previously unappreciated temporal and contextual factors have profound effects on MAP kinase function. This is exemplified by recent studies of the regulation of the ERK1/2 MAP kinase cascade by GPCRs.

Beta-arrestin-dependent formation of beta2 adrenergic receptor-Src protein kinase complexes.

The Ras-dependent activation of mitogen-activated protein (MAP) kinase pathways by many receptors coupled to heterotrimeric guanine nucleotide binding proteins (G proteins) requires the activation of Src family tyrosine kinases. Stimulation of beta2 adrenergic receptors resulted in the assembly of a protein complex containing activated c-Src and the receptor. Src recruitment was mediated by beta-arrestin, which functions as an adapter protein, binding both c-Src and the agonist-occupied receptor.

Ras-dependent mitogen-activated protein kinase activation by G protein-coupled receptors. Convergence of Gi- and Gq-mediated pathways on calcium/calmodulin, Pyk2, and Src kinase.

Many receptors that couple to heterotrimeric guanine-nucleotide binding proteins (G proteins) have been shown to mediate rapid activation of the mitogen-activated protein kinases Erk1 and Erk2. In different cell types, the signaling pathways employed appear to be a function of the available repertoire of receptors, G proteins, and effectors. In HEK-293 cells, stimulation of either alpha1B- or alpha2A-adrenergic receptors (ARs) leads to rapid 5-10-fold increases in Erk1/2 phosphorylation.

Gbetagamma subunits mediate Src-dependent phosphorylation of the epidermal growth factor receptor. A scaffold for G protein-coupled receptor-mediated Ras activation.

In many cells, stimulation of mitogen-activated protein kinases by both receptor tyrosine kinases and receptors that couple to pertussis toxin-sensitive heterotrimeric G proteins proceed via convergent signaling pathways. Both signals are sensitive to inhibitors of tyrosine protein kinases and require Ras activation via phosphotyrosine-dependent recruitment of Ras guanine nucleotide exchange factors. Receptor tyrosine kinase stimulation mediates ligand-induced receptor autophosphorylation, which creates the initial binding sites for SH2 domain-containing docking proteins.

Role of c-Src tyrosine kinase in G protein-coupled receptor- and Gbetagamma subunit-mediated activation of mitogen-activated protein kinases.

Several G protein-coupled receptors that interact with pertussis toxin-sensitive heterotrimeric G proteins mediate Ras-dependent activation of mitogen-activated protein (MAP) kinases. The mechanism involves Gbetagamma subunit-mediated increases in tyrosine phosphorylation of the Shc adapter protein, Shc*Grb2 complex formation, and recruitment of Ras guanine nucleotide exchange factor activity. We have investigated the role of the ubiquitous nonreceptor tyrosine kinase c-Src in activation of the MAP kinase pathway via endogenous G protein-coupled lysophosphatidic acid (LPA) receptors or by transient expression of Gbetagamma subunits in COS-7 cells.