Epinephrine Production in Th17 Cells and Experimental Autoimmune Encephalitis.

Epinephrine is a hormone secreted primarily by medullary cells of the adrenal glands which regulates permeability of blood-brain barrier (BBB). Recent studies showed signaling by epinephrine/epinephrine receptor in T cells is involved in autoimmune diseases. Nevertheless, the production of epinephrine by T cells and its pathogenic function in T cells are not well investigated. Our results show that phenylethanol N-methyltransferase (PNMT), a rate-limiting enzyme of epinephrine synthesis, is specifically expressed in vitro in differentiated TH17 cells and in tissue-resident TH17 cells. Indeed, expression levels of enzymes involved in epinephrine production are higher in TH17 cells from animals after EAE induction. The induction of PNMT was not observed in other effector T cell subsets or regulatory T cells. Epinephrine producing TH17 cells exhibit co-expression of GM-CSF, suggesting they are pathogenic TH17 cells. To delineate the function of epinephrine-production in TH17 cells, we generated a TH17-specific knockout of tyrosine hydroxylase (Th) by breeding a Th-flox and a ROR-gt-CRE mouse (Th-CKO). Th-CKO mice are developmentally normal with an equivalent T lymphocyte number in peripheral lymphoid organs. Th-CKO mice also show an equivalent number of TH17 cells in vivo and following in vitro differentiation. To test whether epinephrine-producing TH17 cells are key for breaching the BBB, migration of T cells through mouse brain endothelial cells was investigated in vitro. Both epi+ wild-type and epi- TH17 cells migrate through an endothelial cell barrier. Mice were immunized with MOG peptide to induce experimental autoimmune encephalitis (EAE) and disease progression was monitored. Although there is a reduced infiltration of CD4+ T cells in Th-CKO mice, no difference in clinical score was observed between Th-CKO and wild-type control mice. Increased neutrophils were observed in the central nervous system of Th-CKO mice, suggesting an alternative pathway to EAE progression in the absence of TH17 derived epinephrine.

Trace amines produced by skin bacteria accelerate wound healing in mice.

Certain skin bacteria are able to convert aromatic amino acids (AAA) into trace amines (TA) that act as neuromodulators. Since the human skin and sweat contain a comparatively high content of AAA one can expect that such bacteria are able to produce TA on our skin. Here we show that TA-producing Staphylococcus epidermidis strains expressing SadA are predominant on human skin and that TA accelerate wound healing. In wounded skin, keratinocytes produce epinephrine (EPI) that leads to cell motility inhibition by ß2-adrenergic receptor (ß2-AR) activation thus delay wound healing. As ß2-AR antagonists, TA and dopamine (DOP) abrogate the effect of EPI thus accelerating wound healing both in vitro and in a mouse model. In the mouse model, the S. epidermidis wild type strain accelerates wound healing compared to its ΔsadA mutant. Our study demonstrates that TA-producing S. epidermidis strains present on our skin might be beneficial for wound healing.

The Impact of MNRI Therapy on the Levels of Neurotransmitters Associated with Inflammatory Processes.

The neurotransmitter levels of representatives from five different diagnosis groups were tested before and after participation in the MNRI®-Masgutova Neurosensorimotor Reflex Intervention. The purpose of this study was to ascertain neurological impact on (1) Developmental disorders, (2) Anxiety disorders/OCD (Obsessive Compulsive Disorder), PTSD (Post-Traumatic Stress disorder), (3) Palsy/Seizure disorders, (4) ADD/ADHD (Attention Deficit Disorder/Attention Deficit Disorder Hyperactive Disorder), and (5) ASD (Autism Spectrum Disorder) disorders. Each participant had a form of neurological dysregulation and typical symptoms respective to their diagnosis. These diagnoses have a severe negative impact on the quality of life, immunity, stress coping, cognitive skills, and social assimilation. This study showed a trend towards optimization and normalization of neurological and immunological functioning, thus supporting the claim that the MNRI method is an effective non-pharmacological neuromodulation treatment of neurological disorders. The effects of MNRI on inflammation have not yet been assessed. The resulting post-MNRI changes in participants' neurotransmitters show significant adjustments in the regulation of the neurotransmitter resulting in being calmer, a decrease of hypervigilance, an increase in stress resilience, behavioral and emotional regulation improvements, a more positive emotional state, and greater control of cognitive processes. In this paper, we demonstrate that the MNRI approach is an intervention that reduces inflammation. It is also likely to reduce oxidative stress and encourage homeostasis of excitatory neurotransmitters. MNRI may facilitate neurodevelopment, build stress resiliency, neuroplasticity, and optimal learning opportunity. There have been no reported side effects of MNRI treatments.

Muscle vasodilator response via potential adrenaline secretion to L-cysteine microinjected in rostral ventrolateral medulla of rats.

We previously found that the thiol amino acid L-cysteine microinjected into rat medullary autonomic areas produces changes in arterial blood pressure (AP) via ionotropic excitatory amino acid receptors (iEAAr), but its effect on vascular beds is still unknown. Rostral ventrolateral medulla (RVLM) pressor area includes adrenal and lumbar presympathetic neurons which activation could cause opposite muscle vascular responses: vasodilation versus vasoconstriction. However, there are few data on the vasodilator response in rats. Ionotropic EAAr activation alone with L-cysteine may be effective to differentiate RVLM sites for those opposite responses. To test it, muscle blood flow responses to L-cysteine were mapped in the ventrolateral medulla (VLM) of rats. In anesthetized rats with a cranial window above the VLM, hindquarter flow (HQF) and AP were monitored, providing hindquarter resistance (HQR) by dividing AP by HQF. L-Cysteine mapping in VLM including caudal depressor vasodilator area defined with L-glutamate showed HQR responses in parallel to AP responses, suggesting the importance of iEAAr in muscle vascular regulation. Microinjections of L-cysteine into RVLM succeeded to detect sites of slower muscle vasodilation and blockade of peripheral ß-adrenoceptors abolished this response, indicating potential adrenaline secretion. Although there was no functional topography, the iEAAr activation alone with L-cysteine can differentiate sites of muscle vasodilation from vasoconstriction in rat RVLM. The neuromodulator candidate L-cysteine is a useful tool when chemical stimulation of iEAAr is required.

EPHB6 controls catecholamine biosynthesis by up-regulating tyrosine hydroxylase transcription in adrenal gland chromaffin cells.

EPHB6 is a member of the erythropoietin-producing hepatocellular kinase (EPH) family and a receptor tyrosine kinase with a dead kinase domain. It is involved in blood pressure regulation and adrenal gland catecholamine (CAT) secretion, but several facets of EPHB6-mediated CAT regulation are unclear. In this study, using biochemical, quantitative RT-PCR, immunoblotting, and gene microarray assays, we found that EPHB6 up-regulates CAT biosynthesis in adrenal gland chromaffin cells (AGCCs). We observed that epinephrine content is reduced in the AGCCs from male Ephb6-KO mice, caused by decreased expression of tyrosine hydroxylase, the rate-limiting enzyme in CAT biosynthesis. We demonstrate that the signaling pathway from EPHB6 to tyrosine hydroxylase expression in AGCCs involves Rac family small GTPase 1 (RAC1), MAP kinase kinase 7 (MKK7), c-Jun N-terminal kinase (JNK), proto-oncogene c-Jun, activator protein 1 (AP1), and early growth response 1 (EGR1). On the other hand, signaling via extracellular signal-regulated kinase (ERK1/2), p38 mitogen-activated protein kinase, and ELK1, ETS transcription factor (ELK1) was not affected by EPHB6 deletion. We further report that EPHB6's effect on AGCCs was via reverse signaling through ephrin B1 and that EPHB6 acted in concert with the nongenomic effect of testosterone to control CAT biosynthesis. Our findings elucidate the mechanisms by which EPHB6 modulates CAT biosynthesis and identify potential therapeutic targets for diseases, such as hypertension, caused by dysfunctional CAT biosynthesis.

Imidacloprid, a neonicotinoid insecticide, facilitates tyrosine hydroxylase transcription and phenylethanolamine N-methyltransferase mRNA expression to enhance catecholamine synthesis and its nicotine-evoked elevation in PC12D cells.

Imidacloprid is a neonicotinoid insecticide acting as an agonist of nicotinic acetylcholine receptors (nAChRs) in the target insects. However, questions about the safety to mammals, including human have emerged. Overactivation of mammalian peripheral catecholaminergic systems leads to onset of tachycardia, hypertension, vomiting, etc., which have been observed in acutely imidacloprid-poisoned patients as well. Physiological activation of the nAChRs is known to drive catecholamine biosynthesis and secretion in mammalian adrenal chromaffin cells. Yet, the impacts of imidacloprid on the catecholaminergic function of the chromaffin cells remain to be evaluated. In this study using PC12D cells, a catecholaminergic cell line derived from the medulla chromaffin-cell tumors of rat adrenal gland, we examined whether imidacloprid itself could impact the catecholamine-synthesizing ability. Imidacloprid alone did facilitate tyrosine hydroxylase (TH) transcription via activation of α3ß4 nAChR and the α7 subunit-comprising receptor. The insecticide showed the TH transcription-facilitating ability at the concentrations of 3 and 30 µM, at which acetylcholine is known to produce physiological responses, including catecholamine secretion through the nAChRs in adrenal chromaffin cells. The insecticide-facilitated TH transcription was also dependent on PKA- and RhoA-mediated signaling pathways. The insecticide coincidentally raised levels of TH and phenylethanolamine N-methyltransferase (PNMT) mRNA, and as a consequence, increased catecholamine production, although the efficacy of the neonicotinoid was lesser than that of nicotine, indicating its partial agonist-like action. Intriguingly, in cultured rat adrenal chromaffin cells, imidacloprid did increase levels of TH and PNMT protein. When the chromaffin cells were treated with nicotine in the presence of the insecticide, nicotine-elevated adrenaline production was enhanced due to facilitation of nicotine-increased TH and PNMT protein expression, and simultaneous enhancement of nicotine-elevated adrenaline secretion also took place. These findings thus suggest that imidacloprid may facilitate the physiological functions of adrenal glands in mammals.

Enhanced activity of hormone sensitive lipase (HSL) in mesenteric but not epididymal fat correlates with higher production of epinephrine in mesenteric adipocytes in rat model of cachectic rheumatoid arthritis.

Cachectic rheumatoid arthritis, the less frequent form of the disease, is associated with loss of fat mass and often more severe course of the disease. Its experimental model represents rat adjuvant arthritis (AA) characterized by edema, lack of appetite, sharp body weight and fat loss. As individual fat depots display functional differences, here we studied lipolytic activity and sensitivity to lipolytic stimuli of nodeless epididymal fat (eWAT) and perinodal mesenteric fat (mWAT) depots at the peak of AA. We also examined changes in catecholamine and cytokine levels involved in lipolysis in plasma and/or isolated adipocytes from both WATs to identify the contribution of local, adipocyte-based processes and/or systemic events to adiposity loss in cachectic rheumatoid arthritis. AA was induced to male Lewis rats by complete Freund's adjuvant. Groups of ad libitum-fed and pair-fed controls were used to distinguish the effects of food restriction from inflammation-induced cachexia. Adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL) and its phosphorylated form (pHSL) were analyzed by western blot. CRP and catecholamine levels in plasma or adipocyte lysates were determined using ELISA kits. Cytokine-induced neutrophil chemoattractant-1 (CINC-1/CXCL1), monocyte chemoattractant protein-1 (MCP-1/CCL2), IL-1ß, IL-6, IL-10 and leptin in adipocyte lysate were analyzed by quantitative protein microarray. Plasma glycerol and FFA were measured spectrophotometrically. AA rats developed severe cachexia, with lower adiposity in mWAT compared to normal and pair-fed controls, whereas in eWAT the adiposity was similarly reduced in AA and pair-fed groups. ATGL levels in both WATs were not affected by AA or pair feeding. AA upregulated levels of HSL, pHSL and pHSL/HSL ratio in mWAT, whereas none of these parameters has changed in eWAT of AA rats or in either WATs of pair-fed rats. In AA rats plasma glycerol was elevated, whereas FFA concentration was reduced. Plasma norepinephrine and epinephrine were increased in AA compared with both groups of controls. In eWAT adipocytes, AA but not pair feeding, upregulated norepinephrine levels. In mWAT adipocytes, AA rats showed higher epinephrine levels than pair-fed controls. Leptin levels in both WATs were depleted in AA animals in accordance with body weight loss. None of the measured cytokines in eWAT and mWAT was enhanced. Our results demonstrate augmented lipolytic activity in mWAT and not eWAT during cachectic arthritis. The adipocyte-derived cytokines do not seem to contribute to activated lipolysis. We first demonstrated enhanced presence of norepinephrine in perinodal adipocytes that may contribute to the regulation of local lipolytic activity by auto/paracrine fashion and thus provide independent fuel supply to activated lymph nodes.

Catecholamine metabolism in paraganglioma and pheochromocytoma: similar tumors in different sites?

Pheochromocytoma (PHEO) and paraganglioma (PGL) are catecholamine-producing neuroendocrine tumors that arise respectively inside or outside the adrenal medulla. Several reports have shown that adrenal glucocorticoids (GC) play an important regulatory role on the genes encoding the main enzymes involved in catecholamine (CAT) synthesis i.e. tyrosine hydroxylase (TH), dopamine ß-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). To assess the influence of tumor location on CAT metabolism, 66 tissue samples (53 PHEO, 13 PGL) and 73 plasma samples (50 PHEO, 23 PGL) were studied. Western blot and qPCR were performed for TH, DBH and PNMT expression. We found a significantly lower intra-tumoral concentration of CAT and metanephrines (MNs) in PGL along with a downregulation of TH and PNMT at both mRNA and protein level compared with PHEO. However, when PHEO were partitioned into noradrenergic (NorAd) and mixed tumors based on an intra-tumoral CAT ratio (NE/E >90%), PGL and NorAd PHEO sustained similar TH, DBH and PNMT gene and protein expression. CAT concentration and composition were also similar between NorAd PHEO and PGL, excluding the use of CAT or MNs to discriminate between PGL and PHEO on the basis of biochemical tests. We observed an increase of TH mRNA concentration without correlation with TH protein expression in primary cell culture of PHEO and PGL incubated with dexamethasone during 24 hours; no changes were monitored for PNMT and DBH at both mRNA and protein level in PHEO and PGL. Altogether, these results indicate that long term CAT synthesis is not driven by the close environment where the tumor develops and suggest that GC alone is not sufficient to regulate CAT synthesis pathway in PHEO/PGL.

How to prevent alcoholic liver disease.

Betaine supplements of alcoholic beverages are proposed to prevent the development of alcoholic liver disease in patients that abuse alcohol. This recommendation is based on the observation of studies where it has been shown in binge drinking and chronic ethanol feeding animal models that betaine prevents liver injury resulting from high blood alcohol levels. The basic observation is that betaine added to ethanol being ingested increases the elimination rate of blood alcohol, which prevents the blood alcohol levels (BALs) from reaching high levels. The mechanism of how betaine does this is postulated to be that betaine causes the increase in the elimination rate by increasing the metabolic rate which generates NAD the rate limiting cofactor of alcohol oxidation by ADH. Betaine does this most likely by supporting the methylation of norepinephrine to form epinephrine by phenylethanolamine N-methyltransferase. Epinephrine is 5 to 10-fold more active than norepinephrine in increasing the metabolic rate.

Partial blockade of nicotinic acetylcholine receptors improves the counterregulatory response to hypoglycemia in recurrently hypoglycemic rats.

Recurrent exposure to hypoglycemia can impair the normal counterregulatory hormonal responses that guard against hypoglycemia, leading to hypoglycemia unawareness. This pathological condition known as hypoglycemia-associated autonomic failure (HAAF) is the main adverse consequence that prevents individuals with type 1 diabetes mellitus from attaining the long-term health benefits of tight glycemic control. The underlying molecular mechanisms responsible for the progressive loss of the epinephrine response to subsequent bouts of hypoglycemia, a hallmark sign of HAAF, are largely unknown. Normally, hypoglycemia triggers both the release and biosynthesis of epinephrine through activation of nicotinic acetylcholine receptors (nAChR) on the adrenal glands. We hypothesize that excessive cholinergic stimulation may contribute to impaired counterregulation. Here, we tested whether administration of the nAChR partial agonist cytisine to reduce postganglionic synaptic activity can preserve the counterregulatory hormone responses in an animal model of HAAF. Compared with nicotine, cytisine has limited efficacy to activate nAChRs and stimulate epinephrine release and synthesis. We evaluated adrenal catecholamine production and secretion in nondiabetic rats subjected to two daily episodes of hypoglycemia for 3 days, followed by a hyperinsulinemic hypoglycemic clamp on day 4. Recurrent hypoglycemia decreased epinephrine responses, and this was associated with suppressed TH mRNA induction (a measure of adrenal catecholamine synthetic capacity). Treatment with cytisine improved glucagon responses as well as epinephrine release and production in recurrently hypoglycemic animals. These data suggest that pharmacological manipulation of ganglionic nAChRs may be promising as a translational adjunctive therapy to avoid HAAF in type 1 diabetes mellitus.

Heart ventricles specific stress-induced changes in ß-adrenoceptors and muscarinic receptors.

The left and right ventricles fulfill different role in heart function. Here we compare chamber specific changes in local catecholamine concentrations; gene expression and the receptor protein amount of all three ß-adrenoceptors (ß-AR) in rat right heart ventricles exposed to acute (1 session) and repeated (7 sessions) immobilization stress (IMMO) vs. previously observed changes in left ventricles. Density of muscarinic receptors as main cardio-inhibitive receptors was also measured. In the right ventricles, noradrenaline and adrenaline were increased. No ß1-AR changes were observed, in spite of the increased sympathetic activity. On the other hand, we have found a decrease of ß2-AR gene expression (reduction to 30%) after 7 IMMO and protein (to 59%) after 1 IMMO. ß3-AR gene expression was increased after 7 IMMO. Muscarinic receptor density was not changed. When comparing correlation in left and right ventricles, there was strong correlation between adrenaline and ß2-AR gene expression, protein and ß3-AR gene expression in the left ventricles while only correlation between adrenaline and ß2-AR mRNA and protein in the right ventricles was found. Our results show that maintenance of cardiac homeostasis under stress conditions are to a great extent achieved by a balance between different receptors and also by a balanced receptor changes in left vs. right ventricles. Taken together, decrease of cardio-stimulating ß2-AR represents a new important mechanism by which ß2-AR contributes to the heart physiology.

Catecholamine production is differently regulated in splenic T- and B-cells following stress exposure.

OBJECTIVES: Stress is accompanied also by a rise in splenic catecholamines (CAs). However, indications about endogenous CA production in the spleen exist but there are no data about the cellular source of this production and possible modification by stress. Therefore, our aim was to investigate whether splenic T- and B-cells are one of main sources in the spleen expressing tyrosine hydroxylase (TH), enzyme crucial for CA biosynthesis, and phenylethanolamine N-methyltransferase (PNMT) which is necessary for epinephrine production. We also investigated whether stress is able to modify expression of both enzymes and CA levels within these cell fractions as well as tried to explain functional consequences of changes observed. RESULTS: T-cells contain higher levels of TH mRNA than B-cells although protein levels appeared similar. On contrary, the PNMT mRNA and protein were higher in B-cells, which appeared to be the main source of PNMT in the spleen. T-cells increased TH and PNMT expression after acute stress while similar rise was observed in B-cells after repeated stress, most probably as a consequence of higher CA turnover in both cell populations. The rise in TH and PNMT was accompanied by an elevation of Bax/Bcl-2 mRNA ratio, number of apoptotic cells and also by a decline of IFN-γ mRNA in both cell types. Reduction of IL-2 and IL-4 mRNA was also observed in B-cells. CONCLUSION: Stress-induced stimulation of endogenous CA biosynthesis in lymphocytes is dependent on the type of lymphocyte population and duration of stressor and leads to attenuated IFN-γ expression and induction of apoptosis. These changes might contribute to dysregulation of specific immune functions involving T- and B-cells and may decrease the ability to cope with intracellular agents following stress situations.

Adrenergic modulation of immune cells: an update.

Sympathoadrenergic pathways are crucial to the communication between the nervous system and the immune system. The present review addresses emerging issues in the adrenergic modulation of immune cells, including: the specific pattern of adrenoceptor expression on immune cells and their role and changes upon cell differentiation and activation; the production and utilization of noradrenaline and adrenaline by immune cells themselves; the dysregulation of adrenergic immune mechanisms in disease and their potential as novel therapeutic targets. A wide array of sympathoadrenergic therapeutics is currently used for non-immune indications, and could represent an attractive source of non-conventional immunomodulating agents.

Fetal glucocorticoid synthesis is required for development of fetal adrenal medulla and hypothalamus feedback suppression.

During pregnancy, fetal glucocorticoid is derived from both maternal supply and fetal secretion. We have created mice with a disruption of the Cyp11a1 gene resulting in loss of fetal steroid secretion but preserving the maternal supply. Cyp11a1null embryos have appreciable although lower amounts of circulating corticosterone, the major mouse glucocorticoid, suggesting that transplacental corticosterone is a major source of corticosterone in fetal circulation. These embryos thus provide a means to examine the effect of fetal glucocorticoids. The adrenal in Cyp11a1 null embryos was disorganized with abnormal mitochondria and oil accumulation. The adrenal medullary cells did not express phenylethanolamine N-methyltransferase and synthesized no epinephrine. Cyp11a1 null embryos had decreased diencephalon Hsd11b1, increased diencephalon Crh, and increased pituitary Pomc expression, leading to higher adrenocorticotropin level in the plasma. These data indicate blunted feedback suppression despite reasonable amounts of circulating corticosterone. Thus, the corticosterone synthesized in situ by the fetus is required for negative feedback suppression of the hypothalamus-pituitary-adrenal axis and for catecholamine synthesis in adrenal medulla.

Adrenal α2-adrenergic receptors in the aging normotensive and spontaneously hypertensive rat.

This study investigates α(2)-adrenergic receptor (α(2)AR) mediated feedback inhibition of catecholamine release from the adrenal medulla of adult (52 weeks) and old (98 weeks) spontaneously hypertensive rats (SHR) and normotensive controls Wistar Kyoto (WKY) rats. Adrenal epinephrine content as well as the spontaneous and the nicotinic-evoked release of epinephrine were similar between adult SHR and WKY rats. Aging produced a significant reduction in epinephrine synthesis in WKY rats. In contrast, in SHR aging produced a significant increase in epinephrine release without significant changes in epinephrine synthesis. The α(2)AR agonist medetomidine abolished (80-90% inhibition) the nicotinic-evoked release of epinephrine in adult SHR and WKY rats. With aging, this effect was unaltered in WKY rats but was significantly decreased in SHR (30% inhibition). Adrenal α(2A)AR mRNA levels were significantly reduced in old SHR compared with age matched WKY rats. In conclusion, in aging the α(2)AR mediated feedback inhibition of epinephrine release from the adrenal medulla is preserved in WKY rats but compromised in SHR, resulting in increased epinephrine release.

Role of reactive oxygen species in the neural and hormonal regulation of the PNMT gene in PC12 cells.

The stress hormone, epinephrine, is produced predominantly by adrenal chromaffin cells and its biosynthesis is regulated by the enzyme phenylethanolamine N-methyltransferase (PNMT). Studies have demonstrated that PNMT may be regulated hormonally via the hypothalamic-pituitary-adrenal axis and neurally via the stimulation of the splanchnic nerve. Additionally, hypoxia has been shown to play a key role in the regulation of PNMT. The purpose of this study was to examine the impact of reactive oxygen species (ROS) produced by the hypoxia mimetic agent CoCl(2), on the hormonal and neural stimulation of PNMT in an in vitro cell culture model, utilizing the rat pheochromocytoma (PC12) cell line. RT-PCR analyses show inductions of the PNMT intron-retaining and intronless mRNA splice variants by CoCl(2) (3.0- and 1.76-fold, respectively). Transient transfection assays of cells treated simultaneously with CoCl(2) and the synthetic glucocorticoid, dexamethasone, show increased promoter activity (18.5-fold), while mRNA levels of both splice variants do not demonstrate synergistic effects. Similar results were observed when investigating the effects of CoCl(2)-induced ROS on the neural stimulation of PNMT via forskolin. Our findings demonstrate that CoCl(2)-induced ROS have synergistic effects on hormonal and neural activation of the PNMT promoter.

Investigations on the triiodothyronine (T3)-specificity of thyrotropic (TSH) and gonadotropic (HCG) hormone in the unicellular Tetrahymena.

In a previous experiment thyrotropin (TSH) increased the triiodothyronine (T3) production of Tetrahymena and chorionic gonadotropin (HCG) moderately overlapped the effect. At present the production of three amino acid type (histamine, serotonin, epinephrine) and one peptide (endorphin) hormones were studied under the effect of TSH or HCG, in tryptone-yeast (TY) or salt (Losina-Losinsky) medium. The duration of the effect was 10 min. TSH significantly (with almost 20%) decreased epinephrine production in TY medium and HCG similarly decreased epinephrine and increased histamine level. In salt solution TSH as well as HCG decreased the level of serotonin. The results show that at this low level of phylogeny TSH effect is not completely thyroxine-specific, however it is not general. HCG overlaps TSH effect on epinephrine and serotonin production, however its effect is broader. The experiments also demonstrate that the effect of pituitary trop-hormones can be bidirectional in Tetrahymena, as histamine level was increased and epinephrine level was decreased by HCG, in the same cells.

Chronic cardiac pressure overload induces adrenal medulla hypertrophy and increased catecholamine synthesis.

Increased activity of the sympathetic system is an important feature contributing to the pathogenesis and progression of chronic heart failure. While the mechanisms and consequences of enhanced norepinephrine release from sympathetic nerves have been intensely studied, the role of the adrenal gland in the development of cardiac hypertrophy and progression of heart failure is less well known. Thus, the aim of the present study was to determine the effect of chronic cardiac pressure overload in mice on adrenal medulla structure and function. Cardiac hypertrophy was induced in wild-type mice by transverse aortic constriction (TAC) for 8 weeks. After TAC, the degree of cardiac hypertrophy correlated significantly with adrenal weight and adrenal catecholamine storage. In the medulla, TAC caused an increase in chromaffin cell size but did not result in chromaffin cell proliferation. Ablation of chromaffin α(2C)-adrenoceptors did not affect adrenal weight or epinephrine synthesis. However, unilateral denervation of the adrenal gland completely prevented adrenal hypertrophy and increased catecholamine synthesis. Transcriptome analysis of microdissected adrenal medulla identified 483 up- and 231 downregulated, well-annotated genes after TAC. Among these genes, G protein-coupled receptor kinases 2 (Grk2) and 6 and phenylethanolamine N-methyltransferase (Pnmt) were significantly upregulated by TAC. In vitro, acetylcholine-induced Pnmt and Grk2 expression as well as enhanced epinephrine content was prevented by inhibition of nicotinic acetylcholine receptors and Ca(2+)/calmodulin-dependent signaling. Thus, activation of preganglionic sympathetic nerves innervating the adrenal medulla plays an essential role in inducing adrenal hypertrophy, enhanced catecholamine synthesis and induction of Grk2 expression after cardiac pressure overload.

The ß2-adrenergic receptor and Her2 comprise a positive feedback loop in human breast cancer cells.

In this study, ß2-AR level was found to be up-regulated in MCF-7 cells overexpressing Her2 (MCF-7/Her2). Correlation of ß2-AR level with Her2 status was demonstrated in breast cancer tissue samples. Constitutive phosphorylation of ERK, mRNA expression up-regulation of catecholamine-synthesis enzymes, and increased epinephrine release were detected in MCF-7/Her2 cells. ß2-AR expression induced by epinephrine and involvement of ERK signaling were validated. The data indicate that Her2 overexpression and excessive phosphorylation of ERK cause epinephrine autocrine release from breast cancer cells, resulting in up-regulation of ß2-AR expression. The data also showed that catecholamine prominently stimulated Her2 mRNA expression and promoter activity. The activation and nuclear translocation of STAT3 triggered by isoproterenol were observed. Enhanced binding activities of STAT3 to the Her2 promoter after isoproterenol stimulation were verified. Using STAT3 shRNA and dominant negative STAT3 mutant, the role of STAT3 in isoproterenol-induced Her2 expression was further confirmed. The data support a model where ß2-AR and Her2 comprise a positive feedback loop in human breast cancer cells.

Vesicular monoamine transporters (VMATs) in adrenal chromaffin cells: stress-triggered induction of VMAT2 and expression in epinephrine synthesizing cells.

Vesicular monoamine transporters (VMATs) mediate transmitter uptake into neurosecretory vesicles. There are two VMAT isoforms, VMAT1 and VMAT2, encoded by separate genes and displaying different cellular distributions and pharmacological properties. We examined the effect of immobilization stress (IMO) on expression of VMATs in the rat adrenal medulla. Under basal conditions, VMAT1 is widely expressed in all adrenal chromaffin cells, while VMAT2 is co-localized with tyrosine hydroxylase (TH) but not phenylethanolamine N-methyltransferase (PNMT), indicating its expression in norepinephrine (NE)-, but not epinephrine (Epi)-synthesizing chromaffin cells. After exposure to IMO, there was no change in levels of VMAT1 mRNA. However, VMAT2 mRNA was elevated after exposure of rats to 2 h IMO once (1× IMO) or daily for 6 days (6× IMO). The changes in VMAT2 mRNA were reflected by increased VMAT2 protein after the repeated IMO. Immunofluorescence revealed an increased number of cells expressing VMAT2 following repeated IMO and its colocalization with PNMT in many chromaffin cells. The findings suggest an adaptive mechanism in chromaffin cells whereby enhanced catecholamine storage capacity facilitates more efficient utilization of the well-characterized heightened catecholamine biosynthesis with repeated IMO stress.