The expression of calcium/calmodulin-dependent kinase IV (CaMKIV) was hitherto thought to be confined to the nervous system. However, a recent genome-wide analysis indicated an association between hypertension and a single-nucleotide polymorphism (rs10491334) of the human CaMKIV gene (CaMK4), which suggests a role for this kinase in the regulation of vascular tone

Cancer development and chemo-resistance are often due to impaired functioning of the p53 tumor suppressor through genetic mutation or sequestration by other proteins. In glioblastoma multiforme (GBM), p53 availability is frequently reduced because it binds to the Murine Double Minute-2 (MDM2) oncoprotein, which accumulates at high concentrations in tumor cells. The use of MDM2 inhibitors that interfere with the binding of p53 and MDM2 has become a valid approach to inhibit cell growth in a number of cancers; however little is known about the efficacy of these inhibitors in GBM. We report that a new small-molecule inhibitor of MDM2 with a spirooxoindolepyrrolidine core structure, named ISA27, effectively reactivated p53 function and inhibited human GBM cell growth in vitro by inducing cell cycle arrest and apoptosis. In immunoincompetent BALB/c nude mice bearing a human GBM xenograft, the administration of ISA27 in vivo activated p53, inhibited cell proliferation and induced apoptosis in tumor tissue. Significantly, ISA27 was non-toxic in an in vitro normal human cell model and an in vivo mouse model. ISA27 administration in combination with temozolomide (TMZ) produced a synergistic inhibitory effect on GBM cell viability in vitro, suggesting the possibility of lowering the dose of TMZ used in the treatment of GBM. In conclusion, our data show that ISA27 releases the powerful antitumor capacities of p53 in GBM cells. The use of this MDM2 inhibitor could become a novel therapy for the treatment of GBM patients.

In this study, we investigated the significance of β2-adrenergic receptor (β2AR) in age-related impaired insulin secretion and glucose homeostasis. We characterized the metabolic phenotype of β2AR-null C57Bl/6N mice (β2AR−/−) by performing in vivo and ex vivo experiments. In vitro assays in cultured INS-1E β-cells were carried out in order to clarify the mechanism by which β2AR deficiency affects glucose metabolism. Adult β2AR−/− mice featured glucose intolerance, and pancreatic islets isolated from these animals displayed impaired glucose-induced insulin release, accompanied by reduced expression of peroxisome proliferator–activated receptor (PPAR)γ, pancreatic duodenal homeobox-1 (PDX-1), and GLUT2. Adenovirus-mediated gene transfer of human β2AR rescued these defects. Consistent effects were evoked in vitro both upon β2AR knockdown and pharmacologic treatment. Interestingly, with aging, wild-type (β2AR+/+) littermates developed impaired insulin secretion and glucose tolerance. Moreover, islets from 20-month-old β2AR+/+ mice exhibited reduced density of β2AR compared with those from younger animals, paralleled by decreased levels of PPARγ, PDX-1, and GLUT2. Overexpression of β2AR in aged mice rescued glucose intolerance and insulin release both in vivo and ex vivo, restoring PPARγ/PDX-1/GLUT2 levels. Our data indicate that reduced β2AR expression contributes to the age-related decline of glucose tolerance in mice.

T he pentraxin (PTX) family includes 2 subgroups of proteins that are structurally divided into short and long forms, are encoded by different genes, and are produced by different cells. [1][2][3] PTX3 is the prototype of the long PTX group, which differs from short PTXs by the presence of an unrelated long N-terminal domain giving it a different ligand recognition capacity. 4 PTX3 is highly conserved from mouse to humans (82% identical and 92% conserved amino acids) and is induced by primary inflammatory stimuli in a variety of cell types, 5,6 including mononuclear phagocytes, fibroblasts, adipocytes, dendritic, and endothelial and smooth muscle cells. 5,7 Marked as an innate immunity protein, PTX3 not only regulates inflammatory responses but also is involved in a range of important biological mechanisms, including vascular pathology. In fact, blood vessels produce large amounts of PTX3 during inflammation, and the level of circulating PTX3 increases in several pathological conditions affecting the cardiovascular system. 8,9 Moreover, in advanced atherosclerotic lesions and in patients with vasculitis, the protein is abundantly present in endothelial cells. 10,11 Thus, PTX3 seems to be a rapid marker of primary local innate immunity and inflammation activation and a novel diagnostic tool for vascular disorders. Clinical Perspective on p 1505In addition, high plasma PTX3 has been linked to vascular endothelial dysfunction in several human diseases, including Background-Pentraxin 3 (PTX3), the prototype of long pentraxins, has been described to be associated with endothelial dysfunction in different cardiovascular disorders. No study has yet evaluated the possible direct effect of PTX3 on vascular function. Methods and Results-Through in vitro experiments of vascular reactivity and ultrastructural analyses, we demonstrate that PTX3 induces dysfunction and morphological changes in the endothelial layer through a P-selectin/matrix metalloproteinase-1 pathway. The latter hampered the detachment of endothelial nitric oxide synthase from caveolin-1, leading to an impairment of nitric oxide signaling. In vivo studies showed that administering PTX3 to wild-type mice induced endothelial dysfunction and increased blood pressure, an effect absent in P-selectin-deficient mice. In isolated human umbilical vein endothelial cells, PTX3 significantly blunted nitric oxide production through the matrix metalloproteinase-1 pathway. Finally, using ELISA, we found that hypertensive patients (n=31) have higher plasma levels of PTX3 and its mediators P-selectin and matrix metalloproteinase-1 than normotensive subjects (n=21). Conclusions-Our data show for the first time a direct role of PTX3 on vascular function and blood pressure homeostasis, identifying the molecular mechanisms involved. The findings in humans suggest that PTX3, P-selectin, and matrix metalloproteinase-1 may be novel biomarkers that predict the onset of vascular dysfunction in hypertensive patients. Here, we demonstrate that (1) PTX3 induces vascular dysfuncti...

Abstract-Recently it has been demonstrated that catecholamines are produced and used by macrophages and mediate immune response. The aim of this study is to verify whether endothelial cells (ECs), which are of myeloid origin, can produce catecholamines. We demonstrated that genes coding for tyrosine hydroxylase, Dopa decarboxylase, dopamine ␤ hydroxylase (D␤H), and phenylethanolamine-N-methyl transferase, enzymes involved in the synthesis of catecholamines, are all expressed in basal conditions in bovine aorta ECs, and their expression is enhanced in response to hypoxia. Moreover, hypoxia enhances catecholamine release. To evaluate the signal transduction pathway that regulates catecholamine synthesis in ECs, we overexpressed in bovine aorta ECs either protein kinase A (PKA) or the transcription factor cAMP response element binding, because PKA/cAMP response element binding activation induces tyrosine hydroxylase transcription and activity in response to stress. Both cAMP response element binding and PKA overexpression enhance D␤H and phenylethanolamine-N-methyl transferase gene expression and catecholamine release, whereas H89, inhibitor of PKA, exerts the opposite effect, evidencing the role of PKA/cAMP response element binding transduction pathway in the regulation of catecholamine release in bovine aorta ECs. We then evaluated by immunohistochemistry the expression of tyrosine hydroxylase, Dopa decarboxylase, D␤H, and phenylethanolamine-N-methyl transferase in femoral arteries from hindlimbs of C57Bl/6 mice 3 days after removal of the common femoral artery to induce chronic ischemia. Ischemia evokes tyrosine hydroxylase, Dopa decarboxylase, D␤H, and phenylethanolamine-N-methyl transferase expression in the endothelium. Finally, the pharmacological inhibition of catecholamine release by fusaric acid, an inhibitor of D␤H, reduces the ability of ECs to form network-like structures on Matrigel matrix. In conclusion, our study demonstrates for the first time that ECs are able to synthesize and release catecholamines in response to ischemia. Key Words: catecholamines Ⅲ ischemia Ⅲ endothelium Ⅲ angiogenesis E ndothelial cells (ECs) cover the interior surface of blood vessels throughout the entire circulatory system, and they are involved in many aspects of vascular biology.1-4 Indeed, angiogenesis is a phenomenon intimately associated with EC migration and proliferation during embryonic development. 5Similarly, ECs play major roles in immune and inflammatory reactions by regulating lymphocyte and leukocyte migration into tissues by means of direct interaction with ECs.6 Moreover, ECs have an important role in the regulation of the vascular tone by releasing vasoactive agents controlling smooth muscle cell proliferation and contractility.Indeed, ECs are known to release both vasodilators (NO) and vasoconstrictors (thromboxane, platelet-derived growth factor, and endothelin 1) in response to local and circulating stimuli. [7][8][9][10][11][12][13][14] To this purpose, the endothelium is regulated in a fine way by a s...

Growing evidence indicate that mitochondria play a functional role in arrhythmogenesis. We report here the molecular mechanisms underlying the action of these highly dynamic organelles in the regulation of cell metabolism, action potential and, overall, heart excitability. In particular, we examine the role of cardiac mitochondria in linking metabolism and cell excitability. The importance of the main mitochondrial channels is evaluated as well, including the recently identified calcium uniporter. Promises and pitfalls of potential therapeutic strategies targeting mitochondrial pathways are also assessed.

BackgroundIntegrins are heterodimeric receptors that play a critical role in cell-cell and cell-matrix adhesion processes. Among them, αVβ3 integrin, that recognizes the aminoacidic RGD triad, is reported to be involved in angiogenesis, tissue repair and tumor growth. We have recently synthesized a new and selective ligand of αVβ3 receptor, referred to as RGDechiHCit, that contains a cyclic RGD motif and two echistatin moieties.MethodsThe aim of this study is to evaluate in vitro and in vivo the effects of RGDechiHCit. Therefore, we assessed its properties in cellular (endothelial cells [EC], and vascular smooth muscle cells [VSMC]) and animal models (Wistar Kyoto rats and c57Bl/6 mice) of angiogenesis.ResultsIn EC, but not VSMC, RGDechiHCit inhibits intracellular mitogenic signaling and cell proliferation. Furthermore, RGDechiHCit blocks the ability of EC to form tubes on Matrigel. In vivo, wound healing is delayed in presence of RGDechiHCit. Similarly, Matrigel plugs demonstrate an antiangiogenic effect of RGDechiHCit.ConclusionsOur data indicate the importance of RGDechiHCit in the selective inhibition of endothelial αVβ3 integrin in vitro and in vivo. Such inhibition opens new fields of investigation on the mechanisms of angiogenesis, offering clinical implications for treatment of pathophysiological conditions such as cancer, proliferative retinopathy and inflammatory disease.

Rationale: Endothelial progenitor cells (EPCs) are present in the systemic circulation and home to sites of ischemic injury where they promote neoangiogenesis. β 2 -Adrenergic receptor (β 2 AR) plays a critical role in vascular tone regulation and neoangiogenesis. Objective: We aimed to evaluate the role of β 2 AR on EPCs’ function. Methods and Results: We firstly performed in vitro analysis showing the expression of β 2 AR on EPCs. Stimulation of wild-type EPCs with β-agonist isoproterenol induced a significant increase of Flk-1 expression on EPCs as assessed by fluorescence-activated cell sorter. Moreover, β 2 AR stimulation induced a significant increase of cell proliferation, improved the EPCs migratory activity, and enhanced the EPCs’ ability to promote endothelial cell network formation in vitro. Then, we performed in vivo studies in animals model of hindlimb ischemia. Consistent with our in vitro results, in vivo EPCs’ treatment resulted in an improvement of impaired angiogenic phenotype in β 2 AR KO mice after induction of ischemia, whereas no significant amelioration was observed when β 2 AR knock out (KO) EPCs were injected. Indeed, wild-type–derived EPCs’ injection resulted in a significantly higher blood flow restoration in ischemic hindlimb and higher capillaries density at histological analysis as compared with not treated or β 2 AR KO EPC-treated mice. Conclusions: The present study provides the first evidence that EPCs express a functional β 2 AR. Moreover, β 2 AR stimulation results in EPCs proliferation, migration, and differentiation, enhancing their angiogenic ability, both in vitro and in vivo, leading to an improved response to ischemic injury in animal models of hindlimb ischemia.