In vivo characterization of the novel neuropeptide Y Y1 receptor antagonist H 409/22

Inhalational Anesthetics Inhibit Neuroglioma Cell Proliferation and Migration via miR-138, -210 and -335

Inhalational anesthetics was previously reported to suppress glioma cell malignancy but underlying mechanisms remain unclear. The present study aims to investigate the effects of sevoflurane and desflurane on glioma cell malignancy changes via microRNA (miRNA) modulation. The cultured H4 cells were exposed to 3.6% sevoflurane or 10.3% desflurane for 2 h. The miR-138, -210 and -335 expression were determined with qRT-PCR. Cell proliferation and migration were assessed with wound healing assay, Ki67 staining and cell count kit 8 (CCK8) assay with/without miR-138/-210/-335 inhibitor transfections. The miRNA downstream proteins, hypoxia inducible factor-1α (HIF-1α) and matrix metalloproteinase 9 (MMP9), were also determined with immunofluorescent staining. Sevoflurane and desflurane exposure to glioma cells inhibited their proliferation and migration. Sevoflurane exposure increased miR-210 expression whereas desflurane exposure upregulated both miR-138 and miR-335 expressions. The administration of inhibitor of miR-138, -210 or -335 inhibited the suppressing effects of sevoflurane or desflurane on cell proliferation and migration, in line with the HIF-1α and MMP9 expression changes. These data indicated that inhalational anesthetics, sevoflurane and desflurane, inhibited glioma cell malignancy via miRNAs upregulation and their downstream effectors, HIF-1α and MMP9, downregulation. The implication of the current study warrants further study.

Expression of matrix metalloproteinase 2 and 9 in breast cancer and breast fibroadenoma: a randomized, double-blind study

Background

Matrix metalloproteinases (MMPs) 2 and 9 may play an important role in cell proliferation and dissemination of cancer. However, few studies have compared the expression of these proteins between breast cancer and fibroadenoma.

Material and methods

A randomized, double-blind study was carried out in 66 premenopausal women, aged 20-49 years, who had been diagnosed with fibroadenoma or breast cancer. The patients were divided into two groups: Group A, control (fibroadenoma, n=36) and Group B, study (cancer, n=30). Immunohistochemical analysis was performed using tissue samples of fibroadenoma and breast cancer to assess MMP-2 and MMP-9 antigen expression. Cells were considered positive if exhibiting brown cytoplasmic staining. Fisher’s exact test was used to compare the percentage of cases with cells expressing MMP-2 and MMP-9 in control and study groups (p < 0.05).

Results

Light microscopy showed a higher concentration of cells with positive cytoplasmic staining for MMP-2 and MMP-9 expression in breast cancer than in fibroadenoma. The percentage of cases with cells expressing MMP-2 in the control and study groups was 41.67% and 86.11%, respectively (p < 0.0009), whereas the percentage of cases with cells expressing MMP-9 in groups A and B was 66.67% and 93.33%, respectively (p<0.0138). MMP-2 and MMP-9 positive expression was significantly higher in moderately differentiated tumors compared to well and poorly differentiated tumors, p <0.005 and p<0.001, respectively.

Conclusions

The current study shows that MMP-2 and MMP-9 protein expression was significantly higher in the breast cancer than in the fibroadenoma and also in moderately differentiated breast cancer.

Differential effects of metoprolol and atenolol to neuropeptide Y blockade in coronary artery disease

OBJECTIVE

To explore possible differential effects between metoprolol and atenolol in patients with coronary artery disease.

DESIGN

The study was randomized, double blind, two-way crossover with the Y1 antagonist AR-H040922 given as IV infusion for 2 h or placebo. Most patients were treated with metoprolol or atenolol. In a post hoc analysis we compared the hemodynamic response to exercise of the Y1 antagonist in patients on metoprolol (n = 16) and atenolol (n = 5), and assessed respiratory sinus arrhythmia (RSA), an indirect measurement of cardiac vagal activation, in the placebo phase in patients on metoprolol (n = 26) and on atenolol (n = 24).

RESULTS

1) The Y1 antagonist reduced the systolic blood pressure rise during and after exercise during atenolol, but not during metoprolol, while heart rate and maximal load were similar with the two beta-blockers and not affected by the Y1 antagonist. 2) At equal heart- and respiration-rate 7-8 min after exercise the RSA was significantly lower in atenolol than in metoprolol patients, while no difference was seen at rest before exercise.

CONCLUSION

These findings from this hypothesis generating study indicate that peripheral effects of NPY contribute less to cardiovascular stress reactions in patients on metoprolol than in those on atenolol.

NPY and its involvement in axon guidance, neurogenesis, and feeding

OBJECTIVES

The role of neuropeptides in nervous system function is still in many cases undefined. In the present study we examined a possible role of the 36-amino acid neuropeptide Y (NPY) with regard to three functions: axon guidance and attraction/repulsion, adult neurogenesis, and control of food intake.

METHODS

Growth cones from embryonic dorsal root ganglion neurons were studied in culture during asymmetrical gradient application of NPY. Growth cones were monitored over a 60-min period, and final turning angle and growth rate were recorded. In the second part the NPY Y(1) and Y(2) receptors were studied in the subventricular zone, the rostral migratory stream, and the olfactory bulb in normal mice and mice with genetically deleted NPY Y(1) or Y(2) receptors. In the third part an anorectic mouse was analyzed with immunohistochemistry.

RESULTS

1) NPY elicited an attractive turning response and an increase in growth rate, effects exerted via the NPY Y(1) receptor. 2) The NPY Y(1) receptor was expressed in neuroblasts in the anterior rostral migratory stream. Mice deficient in the Y(1) or Y(2) receptor had fewer proliferating precursor cells and neuroblasts in the subventricular zone and rostral migratory stream and fewer neurons in the olfactory bulb expressing calbindin, calretinin or tyrosine hydroxylase. 3) In the anorectic mouse markers for microglia were strongly upregulated in the arcuate nucleus and in projection areas of the NPY/agouti gene-related protein arcuate system.

CONCLUSION

NPY participates in several mechanisms involved in the development of the nervous system and is of importance in the control of food intake.

Receptor autoradiography as mean to explore the possible functional relevance of neuropeptides: focus on new agonists and antagonists to study natriuretic peptides, neuropeptide Y and calcitonin gene-related peptides

Over the past 20 years, receptor autoradiography has proven most useful to provide clues as to the role of various families of peptides expressed in the brain. Early on, we used this method to investigate the possible roles of various brain peptides. Natriuretic peptide (NP), neuropeptide Y (NPY) and calcitonin (CT) peptide families are widely distributed in the peripheral and central nervous system and induced multiple biological effects by activating plasma membrane receptor proteins. The NP family includes atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP). The NPY family is composed of at least three peptides NPY, peptide YY (PYY) and the pancreatic polypeptides (PPs). The CT family includes CT, calcitonin gene-related peptide (CGRP), amylin (AMY), adrenomedullin (AM) and two newly isolated peptides, intermedin and calcitonin receptor-stimulating peptide (CRSP). Using quantitative receptor autoradiography as well as selective agonists and antagonists for each peptide family, in vivo and in vitro assays revealed complex pharmacological responses and radioligand binding profile. The existence of heterogeneous populations of NP, NPY and CT/CGRP receptors has been confirmed by cloning. Three NP receptors have been cloned. One is a single-transmembrane clearance receptor (NPR-C) while the other two known as CG-A (or NPR-A) and CG-B (or NPR-B) are coupled to guanylate cyclase. Five NPY receptors have been cloned designated as Y(1), Y(2), Y(4), Y(5) and y(6). All NPY receptors belong to the seven-transmembrane G-protein coupled receptors family (GPCRs; subfamily type I). CGRP, AMY and AM receptors are complexes which include a GPCR (the CT receptor or CTR and calcitonin receptor-like receptor or CRLR) and a single-transmembrane domain protein known as receptor-activity-modifying-proteins (RAMPs) as well as an intracellular protein named receptor-component-protein (RCP). We review here tools that are currently available in order to target each NP, NPY and CT/CGRP receptor subtype and establish their respective pathophysiological relevance.

Synthesis of fluorinated 1-(3-morpholin-4-yl-phenyl)-ethylamines

The synthesis of four (+/-)-fluorinated 1-(3-morpholin-4-yl-phenyl)-ethylamines and an enantioselective approach to these amines through reductive amination are described.

Mitogenic actions of neuropeptide Y in vascular smooth muscle cells: synergetic interactions with the beta-adrenergic system

Neuropeptide Y (NPY), a sympathetic cotransmitter and vasoconstrictor, also stimulates vascular smooth muscle cell (VSMC) growth, but which of its Y1-Y5 receptors are involved remains unclear. In quiescent rat VSMCs, NPY receptor mRNAs were undetectable (reverse transcription-polymerase chain reaction), but Y1, Y2, and Y5 expression were upregulated or induced following NPY treatment. Concomitantly, NPY increased up to twofold [3H]thymidine incorporation and cell number bimodally, with a high-affinity peak at pM and low affinity peak at nM concentrations. The Y1 or Y5 (not Y2) antagonist alone did not change the high-affinity peak but decreased the low affinity peak by 50% and fully blocked NPY's response when combined. In VSMCs lacking NPY receptors and responsiveness, transient Y1 cDNA transfection restored their mitogenic response (blocked by the Y1 antagonist). In VSMCs with low or no NPY responsiveness, pre-exposure to beta-adrenergic receptor agonist (isoproterenol), forskolin, or dibutyryl cAMP augmented NPY's mitogenic effect, while upregulating Y1, Y2, and Y5 receptor expression (isoproterenol only). Thus, NPY is a potent vascular mitogen acting via Y1 and Y5 receptors. However, since their expression is low in nonproliferating cells, amplification of NPY's mitogenic responses requires upregulation of at least the Y1 receptor by NPY itself or beta-adrenergic, cAMP-dependent activation.

Impaired angiogenesis in neuropeptide Y (NPY)-Y2 receptor knockout mice

Which of Y1-Y5 receptors (Rs) mediate NPY's angiogenic activity was studied using Y2R-null mice and R-specific antagonists. In Y2R-null mice, NPY-induced aortic sprouting and in vivo Matrigel capillary formation were decreased by 50%; Y1R-antagonist blocked the remaining response. NPY-induced sprouting was equally inhibited by Y2R- (and Y5R- but less by Y1R-) antagonists in wild type mice. Spontaneous and NPY-induced revascularization of ischemic gastrocnemius muscles were similarly reduced in Y2R-null mice. Thus, NPY-induced angiogenesis, spontaneous and ischemic, is primarily mediated by Y2Rs. However, Y5Rs and, to a lesser degree Y1Rs, also may play a role in NPY-mediated angiogenesis.

Pharmacology of neuropeptide Y receptor antagonists. Focus on cardiovascular functions

Neuropeptide Y is one of the most abundant mammalian neuropeptides identified to date. The possible actions of neuropeptide Y, that is co-localized and released with noradrenaline, as a sympathetic co-transmitter has attracted much attention during the last decade. In recent years, several non-peptide antagonists with high subtype selectivity for neuropeptide Y receptors have been introduced. With them, the status of neuropeptide Y as a sympathetic transmitter has been established, and so have profound cardiovascular effects mediated by neuropeptide Y Y(1) and Y(2) receptors. Significant release of neuropeptide Y occurs especially upon stronger sympathetic activation, and recent data suggest that the importance of neuropeptide Y seems enhanced in stress-related cardiovascular disorders. The true significance of neuropeptide Y has thus started to unfold, owing to the presence of the first generation of selective neuropeptide Y receptor antagonists. This review concerns the pharmacology of these agents, what we have learnt from them, and might find out in the future.

Vascular pharmacology of BIIE0246, the first selective non-peptide neuropeptide Y Y(2) receptor antagonist, in vivo

BIIE0246, a recently introduced non-peptide neuropeptide Y (NPY) Y(2) receptor antagonist, was pharmacologically characterized in vivo, on vascular responses evoked in the anaesthetized pig. The NPY Y(2) receptor agonist N-acetyl[Leu(28)Leu(31)]NPY(24-36) evoked dose-dependent vasoconstriction in spleen. These vascular responses were potently and dose-dependently antagonized by BIIE0246. Significant inhibition was seen already at 1 nmol kg(-1), whereas at 100 nmol kg(-1) of BIIE0246 these responses were completely abolished. The ID(50) value for this antagonism was 2.1 nmol kg(-1). Peptide YY (PYY) evoked dose-dependent vasoconstriction in both kidney and spleen, vascular responses mediated by the NPY Y(1) receptor and both NPY Y(1) and Y(2) receptors, respectively. Only the splenic response was inhibited by BIIE0246, the effect of which reached significance at 1 nmol kg(-1). Already 30 min after the last dose of BIIE0246 there was a significant recovery of the PYY-evoked splenic vasoconstriction, and a further 60 min later, this response was no longer significantly inhibited compared to control. BIIE0246 (100 nmol kg(-1)) did not affect renal and splenic vasoconstrictor responses either to the NPY Y(1) receptor agonist [Leu(31)Pro(34)]NPY, the alpha(1)-adrenoceptor agonist phenylephrine, the P2X(1)-purinoceptor agonist alpha,beta-methylene ATP or angiotensin II, demonstrating both selectivity and specificity for the NPY Y(2) receptor in vivo. It is concluded that BIIE0246 is a highly potent and selective NPY Y(2) receptor antagonist, albeit with rather short duration of action, in vivo. BIIE0246 thus represents the first interesting tool for studies on NPY Y(2) receptor-mediated transmission in vivo.

Pharmacology of H 394/84, a dihydropyridine neuropeptide Y Y(1) receptor antagonist, in vivo

The object of the present paper was to investigate the in vivo pharmacological profile of the dihydropyridine neuropeptide Y Y(1) receptor antagonist 1,4-Dihydro-4-[3-[[[[3-[spiro(indene-4,1'-piperidin-1-yl)]propyl]amino]carbonyl]amino]phenyl]-2,6-dimethyl-3,5-pyridine dicarboxylic acid, dimethylester (H 394/84). The renal vasoconstrictor response to neuropeptide Y in anaesthetized rats was dose-dependently antagonized by H 394/84 (ID(50) value=41+/-4 nmol/kg/min), whereas the renal vascular responses to noradrenaline and angiotensin II were only slightly affected by H 394/84 (500 nmol/kg/min). In pigs pretreated with reserpine and transection of sympathetic nerves (depleted of noradrenaline), H 394/84 dose-dependently antagonized renal and femoral vasoconstrictor responses evoked by sympathetic nerve activation (neuronally released neuropeptide Y) and exogenous neuropeptide Y. Significant inhibition was seen already at 1.0 nmol/kg/min, when plasma levels of the antagonist reached 29+/-4 nM. Around 70% of the antagonism remained 90 min after H 394/84 was given. The disposition of H 394/84 fits a biexponential model with initial and terminal half-lives of 2.6 and 48 min, respectively. H 394/84 (100 nmol/kg/min) did not inhibit vascular responses to neuropeptide Y Y(2) receptor-, alpha-adrenoceptor- or purinoceptor-activation in the pig in vivo. It is concluded that H 394/84 is a potent neuropeptide Y Y(1) receptor antagonist with rather long duration of action in vivo. The selectivity and specificity in vivo is more than 100-fold, and H 394/84 antagonizes vascular responses to exogenous and endogenous, neuronally released, neuropeptide Y with similar potency.