While genome-wide association studies are ongoing to identify sequence variation influencing susceptibility to major depressive disorder (MDD), epigenetic marks, such as DNA methylation, which can be influenced by environment, might also play a role. Here we present the first genome-wide DNA methylation (DNAm) scan in MDD. We compared 39 postmortem frontal cortex MDD samples to 26 controls. DNA was hybridized to our Comprehensive High-throughput Arrays for Relative Methylation (CHARM) platform, covering 3.5 million CpGs. CHARM identified 224 candidate regions with DNAm differences >10%. These regions are highly enriched for neuronal growth and development genes. Ten of 17 regions for which validation was attempted showed true DNAm differences; the greatest were in PRIMA1, with 12–15% increased DNAm in MDD (p = 0.0002–0.0003), and a concomitant decrease in gene expression. These results must be considered pilot data, however, as we could only test replication in a small number of additional brain samples (n = 16), which showed no significant difference in PRIMA1. Because PRIMA1 anchors acetylcholinesterase in neuronal membranes, decreased expression could result in decreased enzyme function and increased cholinergic transmission, consistent with a role in MDD. We observed decreased immunoreactivity for acetylcholinesterase in MDD brain with increased PRIMA1 DNAm, non-significant at p = 0.08.While we cannot draw firm conclusions about PRIMA1 DNAm in MDD, the involvement of neuronal development genes across the set showing differential methylation suggests a role for epigenetics in the illness. Further studies using limbic system brain regions might shed additional light on this role.

Opiate addiction is characterized by progressive increases in drug intake over time suggesting maladaptive changes in motivational and reward systems. These behaviors are mediated by dopaminergic neurons originating from the ventral tegmental area (VTA), and longterm changes of these dopaminergic neurons are attributed to increased postsynaptic glutamatergic activation. Indeed, chronic morphine administration is known to increase AMPA receptor glutamate receptor 1 (GluR1) subunit in the VTA. However, there is no ultrastructural evidence that morphine affects the expression or surface availability of GluR1 subunits in VTA neurons of defined distribution or transmitter phenotype. Therefore, we examined electron microscopic immunolabeling of GluR1 and tyrosine hydroxylase (TH) in two VTA regions of rats perfused 1 h after a single injection of morphine, or chronic morphine in intermittent-escalating doses for 14 d, and appropriate saline controls. Acute morphine administration produced a significant increase in GluR1 immunogold particles at the plasma membrane and postsynaptic densities in both TH-and non-TH-containing dendrites in the parabrachial VTA, a region that contains mainly prefrontal-cortical-projecting dopaminergic neurons involved in motivation and drug-seeking behavior. Chronic morphine administration maintained the increased synaptic GluR1 labeling in the parabrachial VTA, but also increased the number of GluR1-labeled synapses and TH immunoreactivity in dendrites of the paranigral VTA where substantially more dopaminergic neurons project to limbic structures implicated in locomotor activation and reward. These results demonstrate a region-and dose-dependent redistribution of GluR1-containing AMPA receptors, which is consistent with acute morphine activation of cortical-projecting VTA neurons and chronic morphine activation of limbic-projecting VTA neurons.

Women are less susceptible to the cerebrovascular complications of hypertension, such as a stroke and vascular dementia. The mechanism of such protection may be related to a reduced vulnerability of women to the cerebrovascular actions of hypertension. To test this hypothesis, we used a model of hypertension based on infusion of angiotensin II (ANG II), an octapeptide that plays a key role in hypertension and produces cerebrovascular dysregulation. Cerebral blood flow (CBF) was monitored by laser-Doppler flowmetry in anesthetized (urethane-chloralose) C57BL/6J male and female mice equipped with a cranial window. ANG II administration (0.25 mug.kg(-1).min(-1) iv x 30-45 min) elevated arterial pressure equally in both sexes but attenuated the CBF increase induced by whisker stimulation or by the endothelium-dependent vasodilator acetylcholine (ACh) in male but not in female mice. The administration of ANG II for 7 days (2.74 mg.kg(-1).day(-1)), using osmotic minipumps, also attenuated these cerebrovascular responses in male, but not female, mice. The reduced susceptibility to the effect of ANG II in female mice was abolished by ovariectomy and reinstated by estrogen administration to ovariectomized mice. Administration of estrogen to male mice abolished the ANG II-induced attenuation of CBF responses. We conclude that female mice are less susceptible to the cerebrovascular dysregulation induced by ANG II, an effect related to estrogen. Such protection from the deleterious cerebrovascular effects of hypertension may play a role in the reduced vulnerability to the cerebrovascular complications of hypertension observed in women.

No abstract

G protein-coupled receptors (GPCRs) are integral cell-surface proteins having a central role in tumor growth and metastasis. However, several GPCRs retain an atypical intracellular/nuclear location in various types of cancer. The pathological significance of this is currently unknown. Here we extend this observation by showing that the bradykinin B2R (BK-B2R) is nuclearly expressed in the human triple-negative breast cancer (TNBC) cell line MDA-MB-231 and in human clinical specimens of TNBC. We posited that these “nuclearized” receptors could be involved in oncogenic signaling linked to aberrant growth and survival maintenance of TNBC. We used cell-penetrating BK-B2R antagonists, including FR173657 and novel transducible, cell-permeable forms of the peptide B2R antagonist HOE 140 (NG68, NG134) to demonstrate their superior efficacy over impermeable ones (HOE 140), in blocking proliferation and promoting apoptosis of MDA-MB-231 cells. Some showed an even greater antineoplastic activity over conventional chemotherapeutic drugs in vitro. The cell-permeable B2R antagonists had less to no anticancer effects on B2R shRNA-knockdown or non-B2R expressing (COS-1) cells, indicating specificity in their action. Possible mechanisms of their anticancer effects may involve activation of p38kinase/p27Kip1 pathways. Together, our data support the existence of a possible intracrine signaling pathway via internal/nuclear B2R, critical for the growth of TNBC cells, and identify new chemical entities that enable to target the corresponding intracellular GPCRs.

1 The e ects of tachykinin NK 1 , NK 2 and NK 3 receptor agonists and antagonists were measured on blood pressure (MAP) and heart rate (HR) after bilateral microinjection into the substantia nigra (SN) of awake, unrestrained rats. 2 Increasing doses (25 pmol ± 1 nmol) of selective agonists at NK 1 ([Sar 9 ,Met(O 2 ) 11 ]SP), NK 2 ([bAla 8 ]NKA(4 ± 10)) and NK 3 (senktide) receptors into the SN produced tachycardia which was selectively and reversibly blocked by the prior injection of tachykinin antagonists at NK 1 (RP67580, 250 pmol), NK 2 (SR48968, 250 pmol) and NK 3 (R-820, 500 pmol) receptor. A rapid fall in MAP followed by a pressor response was seen with 1 nmol of [Sar 9 ,Met(O 2 ) 11 ]SP. Behavioural activity was elicited by 1 nmol of [Sar 9 ,Met (O 2 11 ]SP (sni ng4face washing=grooming) and senktide (sni ng4wet dog shake4rearing=locomotion). Tachykinin antagonists had no direct cardiovascular or behavioural e ects. 4 These data suggest that the SN is a potential site of modulation of cardiac activity by tachykinins. In addition to the withdrawal of the cardiovagal activity by NK 1 receptor, the three tachykinin receptors appear to increase the sympatho/adrenal drive to the heart. This occurs independently of changes in MAP and behaviour. Hence, this study highlights a new central regulatory mechanism of cardiac autonomic activity.

No abstract

1 The role of nigral tachykinin NK 1 , NK 2 and NK 3 receptors in central cardiovascular regulation was studied by measuring the eects of selective agonists and antagonists on mean arterial pressure (MAP) and heart rate (HR) after bilateral microinjection into the substantia nigra of spontaneously hypertensive rats (SHR ]NKA(4-10)) agonists at 25 and 100 pmol while the NK 3 agonist (senktide, 50 and 100 pmol) had no signi®cant eect. The three agonists had no eect on behaviour, and increases in MAP were elicited by the NK 1 agonist only.3 Whereas antagonists at NK 1 (RP 67580, 500 pmol) and NK 2 (SR 48968, 500 pmol) receptors had no signi®cant eect on MAP and HR, the NK 3 antagonist (R-820, 500 pmol) reduced MAP for over 3 h in SHR. That anti-hypertensive eect did not occur after intracerebroventricular or intravenous injection of R-820. Also, R-820 had no cardiovascular eect in WKY. 4 The anity (K D : 0.7 nM) and densities of speci®c NK 3 receptor binding sites measured in the substantia nigra, ventral tegmental area, hippocampus and amygdala were not signi®cantly dierent in SHR and WKY. 5 It is concluded that endogenous tachykinins exert a tonic activity on NK 3 receptors in the substantia nigra of SHR to maintain high blood pressure. Hence, nigral tachykinin NK 3 receptors may represent a promising therapeutic target in the treatment of arterial hypertension.