Bay w 9798, a dihydropyridine structurally related to nifedipine with no calcium channel-blocking properties, inhibits tumour necrosis factor-alpha-induced vascular cell adhesion molecule-1 expression in endothelial cells by suppressing reactive oxygen species generation

Dihydropyridine Derivatives Modulate Heat Shock Responses and have a Neuroprotective Effect in a Transgenic Mouse Model of Alzheimer's Disease

Heat shock proteins (Hsps) have chaperone activity and play a pivotal role in the homeostasis of proteins by preventing misfolding, by clearing aggregated and damaged proteins from cells, and by maintaining proteins in an active state. Alzheimer’s disease (AD) is thought to be caused by amyloid-β peptide that triggers tau hyperphosphorylation, which is neurotoxic. Although proteostasis capacity declines with age and facilitates the manifestation of neurodegenerative diseases such as AD, the upregulation of chaperones improves prognosis. Our research goal is to identify potent Hsp co-inducers that enhance protein homeostasis for the treatment of AD, especially 1,4-dihydropyridine derivatives optimized for their ability to modulate cellular stress responses. Based on favorable toxicological data and Hsp co-inducing activity, LA1011 was selected for the in vivo analysis of its neuroprotective effect in the APPxPS1 mouse model of AD. Here, we report that 6 months of LA1011 administration effectively improved the spatial learning and memory functions in wild type mice and eliminated neurodegeneration in double mutant mice. Furthermore, Hsp co-inducer therapy preserves the number of neurons, increases dendritic spine density, and reduces tau pathology and amyloid plaque formation in transgenic AD mice. In conclusion, the Hsp co-inducer LA1011 is neuroprotective and therefore is a potential pharmaceutical candidate for the therapy of neurodegenerative diseases, particularly AD.

1,4-Dihydropyridine Derivatives: Dihydronicotinamide Analogues-Model Compounds Targeting Oxidative Stress

Many 1,4-dihydropyridines (DHPs) possess redox properties. In this review DHPs are surveyed as protectors against oxidative stress (OS) and related disorders, considering the DHPs as specific group of potential antioxidants with bioprotective capacities. They have several peculiarities related to antioxidant activity (AOA). Several commercially available calcium antagonist, 1,4-DHP drugs, their metabolites, and calcium agonists were shown to express AOA. Synthesis, hydrogen donor properties, AOA, and methods and approaches used to reveal biological activities of various groups of 1,4-DHPs are presented. Examples of DHPs antioxidant activities and protective effects of DHPs against OS induced damage in low density lipoproteins (LDL), mitochondria, microsomes, isolated cells, and cell cultures are highlighted. Comparison of the AOA of different DHPs and other antioxidants is also given. According to the data presented, the DHPs might be considered as bellwether among synthetic compounds targeting OS and potential pharmacological model compounds targeting oxidative stress important for medicinal chemistry.

Targeted endothelial nanomedicine for common acute pathological conditions

Endothelium, a thin monolayer of specialized cells lining the lumen of blood vessels is the key regulatory interface between blood and tissues. Endothelial abnormalities are implicated in many diseases, including common acute conditions with high morbidity and mortality lacking therapy, in part because drugs and drug carriers have no natural endothelial affinity. Precise endothelial drug delivery may improve management of these conditions. Using ligands of molecules exposed to the bloodstream on the endothelial surface enables design of diverse targeted endothelial nanomedicine agents. Target molecules and binding epitopes must be accessible to drug carriers, carriers must be free of harmful effects, and targeting should provide desirable sub-cellular addressing of the drug cargo. The roster of current candidate target molecules for endothelial nanomedicine includes peptidases and other enzymes, cell adhesion molecules and integrins, localized in different domains of the endothelial plasmalemma and differentially distributed throughout the vasculature. Endowing carriers with an affinity to specific endothelial epitopes enables an unprecedented level of precision of control of drug delivery: binding to selected endothelial cell phenotypes, cellular addressing and duration of therapeutic effects. Features of nanocarrier design such as choice of epitope and ligand control delivery and effect of targeted endothelial nanomedicine agents. Pathological factors modulate endothelial targeting and uptake of nanocarriers. Selection of optimal binding sites and design features of nanocarriers are key controllable factors that can be iteratively engineered based on their performance from in vitro to pre-clinical in vivo experimental models. Targeted endothelial nanomedicine agents provide antioxidant, anti-inflammatory and other therapeutic effects unattainable by non-targeted counterparts in animal models of common acute severe human disease conditions. The results of animal studies provide the basis for the challenging translation endothelial nanomedicine into the clinical domain.

Targeted Drug Delivery to Endothelial Adhesion Molecules

Endothelial cells represent important targets for therapeutic and diagnostic interventions in many cardiovascular, pulmonary, neurological, inflammatory, and metabolic diseases. Targeted delivery of drugs (especially potent and labile biotherapeutics that require specific subcellular addressing) and imaging probes to endothelium holds promise to improve management of these maladies. In order to achieve this goal, drug cargoes or their carriers including liposomes and polymeric nanoparticles are chemically conjugated or fused using recombinant techniques with affinity ligands of endothelial surface molecules. Cell adhesion molecules, constitutively expressed on the endothelial surface and exposed on the surface of pathologically altered endothelium—selectins, VCAM-1, PECAM-1, and ICAM-1—represent good determinants for such a delivery. In particular, PECAM-1 and ICAM-1 meet criteria of accessibility, safety, and relevance to the (patho)physiological context of treatment of inflammation, ischemia, and thrombosis and offer a unique combination of targeting options including surface anchoring as well as intra- and transcellular targeting, modulated by parameters of the design of drug delivery system and local biological factors including flow and endothelial phenotype. This review includes analysis of these factors and examples of targeting selected classes of therapeutics showing promising results in animal studies, supporting translational potential of these interventions.

N-n-butyl haloperidol iodide ameliorates cardiomyocytes hypoxia/reoxygenation injury by extracellular calcium-dependent and -independent mechanisms

N-n-butyl haloperidol iodide (F2) has been shown to antagonize myocardial ischemia/reperfusion injury by blocking calcium channels. This study explores the biological functions of ERK pathway in cardiomyocytes hypoxia/reoxygenation injury and clarifies the mechanisms by which F2 ameliorates cardiomyocytes hypoxia/reoxygenation injury through the extracellular-calcium-dependent and -independent ERK1/2-related pathways. In extracellularcalcium-containing hypoxia/reoxygenation cardiomyocytes, PKCα and ERK1/2 were activated, Egr-1 protein level and cTnI leakage increased, and cell viability decreased. The ERK1/2 inhibitors suppressed extracellular-calcium-containing-hypoxia/reoxygenation-induced Egr-1 overexpression and cardiomyocytes injury. PKCα inhibitor downregulated extracellularcalcium-containing-hypoxia/reoxygenation-induced increase in p-ERK1/2 and Egr-1 expression. F2 downregulated hypoxia/reoxygenation-induced elevation of p-PKCα, p-ERK1/2, and Egr-1 expression and inhibited cardiomyocytes damage. The ERK1/2 and PKCα activators antagonized F2's effects. In extracellular-calcium-free-hypoxia/reoxygenation cardiomyocytes, ERK1/2 was activated, LDH and cTnI leakage increased, and cell viability decreased. F2 and ERK1/2 inhibitors antagonized extracellular-calcium-free-hypoxia/reoxygenation-induced ERK1/2 activation and suppressed cardiomyocytes damage. The ERK1/2 activator antagonized F2's above effects. F2 had no effect on cardiomyocyte cAMP content or PKA and Egr-1 expression. Altogether, ERK activation in extracellular-calcium-containing and extracellular-calcium-free hypoxia/reoxygenation leads to cardiomyocytes damage. F2 may ameliorate cardiomyocytes hypoxia/reoxygenation injury by regulating the extracellular-calcium-dependent PKCα/ERK1/2/Egr-1 pathway and through the extracellular-calcium-independent ERK1/2 activation independently of the cAMP/PKA pathway or Egr-1 overexpression.

Targeted interception of signaling reactive oxygen species in the vascular endothelium

Reactive oxygen species (ROS) are implicated as injurious and as signaling agents in human maladies including inflammation, hyperoxia, ischemia-reperfusion and acute lung injury. ROS produced by the endothelium play an important role in vascular pathology. They quench, for example, nitric oxide, and mediate pro-inflammatory signaling. Antioxidant interventions targeted for the vascular endothelium may help to control these mechanisms. Animal studies have demonstrated superiority of targeting ROS-quenching enzymes catalase and superoxide dismutase to endothelial cells over nontargeted formulations. A diverse arsenal of targeted antioxidant formulations devised in the last decade shows promising results for specific quenching of endothelial ROS. In addition to alleviation of toxic effects of excessive ROS, these targeted interventions suppress pro-inflammatory mechanisms, including endothelial cytokine activation and barrier disruption. These interventions may prove useful in experimental biomedicine and, perhaps, in translational medicine.

Targeted modulation of reactive oxygen species in the vascular endothelium

'Endothelial cells lining vascular luminal surface represent an important site of signaling and injurious effects of reactive oxygen species (ROS) produced by other cells and endothelium itself in ischemia, inflammation and other pathological conditions. Targeted delivery of ROS modulating enzymes conjugated with antibodies to endothelial surface molecules (vascular immunotargeting) provides site-specific interventions in the endothelial ROS, unattainable by other formulations including PEG-modified enzymes. Targeting of ROS generating enzymes (e.g., glucose oxidase) provides ROS- and site-specific models of endothelial oxidative stress, whereas targeting of antioxidant enzymes SOD and catalase offers site-specific quenching of superoxide anion and H(2)O(2). These targeted antioxidant interventions help to clarify specific role of endothelial ROS in vascular and pulmonary pathologies and provide basis for design of targeted therapeutics for treatment of these pathologies. In particular, antibody/catalase conjugates alleviate acute lung ischemia/reperfusion injury, whereas antibody/SOD conjugates inhibit ROS-mediated vasoconstriction and inflammatory endothelial signaling. Encapsulation in protease-resistant, ROS-permeable carriers targeted to endothelium prolongs protective effects of antioxidant enzymes, further diversifying the means for targeted modulation of endothelial ROS.

PECAM-targeted delivery of SOD inhibits endothelial inflammatory response

Elevated generation of reactive oxygen species (ROS) by endothelial enzymes, including NADPH-oxidase, is implicated in vascular oxidative stress and endothelial proinflammatory activation involving exposure of vascular cell adhesion molecule-1 (VCAM-1). Catalase and superoxide dismutase (SOD) conjugated with antibodies to platelet/endothelial cell adhesion molecule 1 (PECAM-1) bind specifically to endothelium and inhibit effects of corresponding ROS, H(2)O(2), and superoxide anion. In this study, anti-PECAM/SOD, but not anti-PECAM/catalase or nontargeted enzymes, including polyethylene glycol (PEG)-SOD, inhibited 2- to 3-fold VCAM expression caused by tumor necrosis factor (TNF), interleukin-1β, and lipopolysaccharide. Anti- PECAM/SOD, but not nontargeted counterparts, accumulated in vascular endothelium after intravenous injection, localized in endothelial endosomes, and inhibited by 70% lipopolysaccharide-caused VCAM-1 expression in mice. Anti-PECAM/SOD colocalized with EEA-1-positive endothelial vesicles and quenched ROS produced in response to TNF. Inhibitors of NADPH oxidase and anion channel ClC3 blocked TNF-induced VCAM expression, affirming that superoxide produced and transported by these proteins, respectively, mediates inflammatory signaling. Anti-PECAM/SOD abolished VCAM expression caused by poly(I:C)-induced activation of toll-like receptor 3 localized in intracellular vesicles. These results directly implicate endosomal influx of superoxide in endothelial inflammatory response and suggest that site-specific interception of this signal attained by targeted delivery of anti-PECAM/SOD into endothelial endosomes may have anti-inflammatory effects.

Bisacurone inhibits adhesion of inflammatory monocytes or cancer cells to endothelial cells through down-regulation of VCAM-1 expression

Bisacurone, one of the active compounds of the traditionally used indigenous herb Curcuma longa Linne (Zingiberaceae), has anti-oxidant, anti-inflammatory, and anti-metastatic activities. We studied how the level of vascular cell adhesion molecule-1 (VCAM-1), one of the key molecules in the development of atherosclerosis as well as carcinogenesis and metastasis, might be affected by bisacurone in tumor necrosis factor-alpha (TNF-alpha)-activated human umbilical vein endothelial cells (HUVECs). Bisacurone dose-dependently inhibited TNF-alpha-mediated expression of VCAM-1. It showed significant suppressive effect on ROS generation in response to TNF-alpha stimulation and it blocked nuclear factor-kappa B (NF-kappaB) p65 translocation into the nucleus and phosphorylation of inhibitory factor kappaBalpha (IkappaBalpha). It also inhibited phosphorylation of Akt and PKC, which are upstream in the regulation of VCAM-1 by TNF-alpha. Furthermore, bisacurone decreased U937 monocyte and human oral cancer cell (Hep-2, QLL-I, SCC-15) adhesion to HUVECs stimulated by TNF-alpha, suggesting that it may inhibit the binding of these cells by regulating the expression of critical adhesion molecules by TNF-alpha. Thus, bisacurone may be beneficial in the treatment of inflammatory diseases, such as atherosclerosis, where inflammatory monocytes are involved in their pathology, and, moreover, in the development of tumors.