Cuscuta reflexa invasion induces Ca release in its host.

PubMed

Albert, M; van der Krol, S; Kaldenhoff, R

2010-05-01

Cuscuta reflexa induces a variety of reaction in its hosts. Some of these are visual reactions, and it is clear that these morphological changes are preceded by events at the molecular level, where signal transduction is one of the early processes. Calcium (Ca(2+)) release is the major second messenger during signal transduction, and we therefore studied Ca(2+) spiking in tomato during infection with C. reflexa. Bioluminescence in aequorin-expressing tomato was monitored for 48 h after the onset of Cuscuta infestation. Signals at the attachment sites were observed from 30 to 48 h. Treatment of aequorin-expressing tomato leaf disks with Cuscuta plant extracts suggested that the substance that induced Ca(2+) release from the host was closely linked to parasite haustoria.

Oligomeric BAX induces mitochondrial permeability transition and complete cytochrome c release without oxidative stress.

PubMed

Li, Tsyregma; Brustovetsky, Tatiana; Antonsson, Bruno; Brustovetsky, Nickolay

2008-11-01

In the present study, we investigated the mechanism of cytochrome c release from isolated brain mitochondria induced by recombinant oligomeric BAX (BAX(oligo)). We found that BAX(oligo) caused a complete release of cytochrome c in a concentration- and time-dependent manner. The release was similar to those induced by alamethicin, which causes maximal mitochondrial swelling and eliminates barrier properties of the OMM. BAX(oligo) also produced large amplitude mitochondrial swelling as judged by light scattering assay and transmission electron microscopy. In addition, BAX(oligo) resulted in a strong mitochondrial depolarization. ATP or a combination of cyclosporin A and ADP, inhibitors of the mPT, suppressed BAX(oligo)-induced mitochondrial swelling and depolarization as well as cytochrome c release but did not influence BAX(oligo) insertion into the OMM. Both BAX(oligo)- and alamethicin-induced cytochrome c releases were accompanied by inhibition of ROS generation, which was assessed by measuring mitochondrial H(2)O(2) release with an Amplex Red assay. The mPT inhibitors antagonized suppression of ROS generation caused by BAX(oligo) but not by alamethicin. Thus, BAX(oligo) resulted in a complete cytochrome c release from isolated brain mitochondria in the mPT-dependent manner without involvement of oxidative stress by the mechanism requiring mitochondrial remodeling and permeabilization of the OMM.

Indomethacin-induced alterations in corticosteroid and prostaglandin release by isolated adrenocortical cells of the cat.

PubMed Central

Laychock, S G; Rubin, R P

1976-01-01

1 The effects of purported prostaglandin synthesis inhibitors on steroid and prostaglandin (E and F) release from trypsin-dispersed cat adrenocortical cells were investigated. 2 Low indomethacin concentrations potentiated adrenocorticotrophin (ACTH)-evoked prostaglandin and steroid release, whereas higher concentrations depressed both responses to ACTH. The steroidogenic response to exogenous prostaglandin E2 was not markedly altered over a wide range of indomethacin concentrations. 3 Indomethacin enhanced basal steroid release but did not enhance basal prostaglandin E or F release. 4 5,8,11,14-Eicosatetraynoic acid (ETA) elicited a concentration-dependent inhibition of ACTH-induced steroid release, but had little effect on prostaglandin E2-induced steroid release. A high concentration of ETA inhibited prostaglandin E and F release. 5 These data are discussed in relation to the concept that prostaglandins provide a critical link in ACTH-induced corticosteroidogenesis. PMID:181110

Cyclosporine Induces Endothelial Cell Release of Complement-Activating Microparticles

PubMed Central

Renner, Brandon; Klawitter, Jelena; Goldberg, Ryan; McCullough, James W.; Ferreira, Viviana P.; Cooper, James E.; Christians, Uwe

2013-01-01

Defective control of the alternative pathway of complement is an important risk factor for several renal diseases, including atypical hemolytic uremic syndrome. Infections, drugs, pregnancy, and hemodynamic insults can trigger episodes of atypical hemolytic uremic syndrome in susceptible patients. Although the mechanisms linking these clinical events with disease flares are unknown, recent work has revealed that each of these clinical conditions causes cells to release microparticles. We hypothesized that microparticles released from injured endothelial cells promote intrarenal complement activation. Calcineurin inhibitors cause vascular and renal injury and can trigger hemolytic uremic syndrome. Here, we show that endothelial cells exposed to cyclosporine in vitro and in vivo release microparticles that activate the alternative pathway of complement. Cyclosporine-induced microparticles caused injury to bystander endothelial cells and are associated with complement-mediated injury of the kidneys and vasculature in cyclosporine-treated mice. Cyclosporine-induced microparticles did not bind factor H, an alternative pathway regulatory protein present in plasma, explaining their complement-activating phenotype. Finally, we found that in renal transplant patients, the number of endothelial microparticles in plasma increases 2 weeks after starting tacrolimus, and treatment with tacrolimus associated with increased C3 deposition on endothelial microparticles in the plasma of some patients. These results suggest that injury-associated release of endothelial microparticles is an important mechanism by which systemic insults trigger intravascular complement activation and complement-dependent renal diseases. PMID:24092930

Effects of hyperthyroidism and hypothyroidism on rat growth hormone release induced by thyrotropin-releasing hormone.

PubMed

Chihara, K; Kato, Y; Ohgo, S; Iwasaki, Y; Maeda, K

1976-06-01

The effect of synthetic thyrotropin-releasing hormone (TRH) on the release of growth hormone (GH) and thyroid-stimulating hormone (TSH) was investigated in euthyroid, hypothyroid, and hyperthyroid rats under urethane anesthesia. In euthyroid control rats, intravenous injection of TRH (200 ng/100 g BW) resulted in a significant increase in both plasma GH and TSH. In rats made hypothyroid by treatment with propylthiouracil or by thyroidectomy, basal GH and TSH levels were significantly elevated with exaggerated responses to TRH. In contrast, plasma GH and TSH responses to TRH were both significantly inhibited in rats made hyperthyroid by L-thyroxine (T4) treatment. These results suggest that altered thyroid status influences GH release as well as TSH secretion induced by TRH in rats.

Caffeine's Attenuation of Cocaine-Induced Dopamine Release by Inhibition of Adenosine.

PubMed

Malave, Lauren B; Broderick, Patricia A

2014-06-01

Background: It is well known that the reinforcing properties of cocaine addiction are caused by the sharp increase of dopamine (DA) in the reward areas of the brain. However, other mechanisms have been speculated to contribute to the increase. Adenosine is one system that is associated with the sleep-wake cycle and is most important in regulating neuronal activity. Thus, more and more evidence is pointing to its involvement in regulating DA release. The current study set out to examine the role of adenosine in cocaine-induced DA release. Methods: Increasing doses of cocaine, caffeine, and their combination, as well as, 8-cyclopentyltheophylline (CPT), an adenosine A1 antagonist (alone and in combination with cocaine) were used to denote a response curve. A novel biosensor, the BRODERICK PROBE ® was implanted in the nucleus accumbens to image the drug-induced surge of DA release in vivo , in the freely moving animal in real time. Results: Combinations of cocaine and caffeine were observed to block the increased release of DA moderately after administration of the low dose (2.5 mg/kg cocaine and 12.5 mg/kg caffeine) and dramatically after administration of the high dose (10 mg/kg cocaine and 50 mg/kg caffeine), suggesting neuroprotection. Similarly, CPT and cocaine showed a decreased DA surge when administered in combination. Thus, the low and high dose of a nonselective adenosine antagonist, caffeine, and a moderate dose of a selective adenosine antagonist, CPT, protected against the cocaine-induced DA release. Conclusions: These results show a significant interaction between adenosine and DA release and suggest therapeutic options for cocaine addiction and disorders associated with DA dysfunction.

Caffeine's Attenuation of Cocaine-Induced Dopamine Release by Inhibition of Adenosine

PubMed Central

Malave, Lauren B.

2014-01-01

Background: It is well known that the reinforcing properties of cocaine addiction are caused by the sharp increase of dopamine (DA) in the reward areas of the brain. However, other mechanisms have been speculated to contribute to the increase. Adenosine is one system that is associated with the sleep-wake cycle and is most important in regulating neuronal activity. Thus, more and more evidence is pointing to its involvement in regulating DA release. The current study set out to examine the role of adenosine in cocaine-induced DA release. Methods: Increasing doses of cocaine, caffeine, and their combination, as well as, 8-cyclopentyltheophylline (CPT), an adenosine A1 antagonist (alone and in combination with cocaine) were used to denote a response curve. A novel biosensor, the BRODERICK PROBE® was implanted in the nucleus accumbens to image the drug-induced surge of DA release in vivo, in the freely moving animal in real time. Results: Combinations of cocaine and caffeine were observed to block the increased release of DA moderately after administration of the low dose (2.5 mg/kg cocaine and 12.5 mg/kg caffeine) and dramatically after administration of the high dose (10 mg/kg cocaine and 50 mg/kg caffeine), suggesting neuroprotection. Similarly, CPT and cocaine showed a decreased DA surge when administered in combination. Thus, the low and high dose of a nonselective adenosine antagonist, caffeine, and a moderate dose of a selective adenosine antagonist, CPT, protected against the cocaine-induced DA release. Conclusions: These results show a significant interaction between adenosine and DA release and suggest therapeutic options for cocaine addiction and disorders associated with DA dysfunction. PMID:25054079

MK-801-induced behavioural sensitisation alters dopamine release and turnover in rat prefrontal cortex.

PubMed

Cui, Xiaoying; Lefevre, Emilia; Turner, Karly M; Coelho, Carlos M; Alexander, Suzy; Burne, Thomas H J; Eyles, Darryl W

2015-02-01

Repeated exposure to psychostimulants that either increase dopamine (DA) release or target N-methyl-D-aspartate (NMDA) receptors can induce behavioural sensitisation, a phenomenon that may be important for the processes of addiction and even psychosis. A critical component of behavioural sensitisation is an increase in DA release within mesocorticolimbic circuits. In particular, sensitisation to amphetamine leads to increased DA release within well-known sub-cortical brain regions and also regulatory regions such as prefrontal cortex (PFC). However, it is unknown how DA release within the PFC of animals is altered by sensitisation to NMDA receptor antagonists. The aims of the present study were twofold, firstly to examine whether a single dose of dizocilpine maleate (MK-801) could induce long-term behavioural sensitisation and secondly to examine DA release in the PFC of sensitised rats. Behavioural sensitisation was assessed by measuring locomotion after drug exposure. DA release in the PFC was measured using freely moving microdialysis. We show that a single dose of MK-801 can induce sensitisation to subsequent MK-801 exposure in a high percentage of rats (66 %). Furthermore, rats sensitised to MK-801 have altered DA release and turnover in the PFC compared with non-sensitised rats. Schizophrenia patients have been postulated to have 'endogenous sensitisation' to psychostimulants. MK-801-induced sensitised rats, in particular when compared with non-sensitised rats, provide a useful model for studying PFC dysfunction in schizophrenia.

The specific GTP requirement for inositol 1,4,5-trisphosphate-induced Ca2+ release from skinned vascular smooth muscle.

PubMed

Saida, K; Twort, C; van Breemen, C

1988-01-01

Exogenous GTP was required for the induction of Ca2+ release from smooth muscle SR by IP3 if endogenous GTP was depleted. NaN3 could function as a partial substitute for GTP as a cofactor for the IP3-induced Ca2+ release from the SR. In contrast to the IP3-induced Ca2+ release, caffeine-induced Ca2+ release from the SR did not require GTP. Pertussis toxin inhibited the IP3-induced Ca2+ release from the SR, whereas it had no effect on caffeine-induced Ca2+ release. These results indicate that in smooth muscle two different Ca2+ release-channels exist in the SR: (a) activated by IP3, and (b) activated by caffeine or Ca2+.

Electronegative LDL induces priming and inflammasome activation leading to IL-1β release in human monocytes and macrophages.

PubMed

Estruch, M; Rajamäki, K; Sanchez-Quesada, J L; Kovanen, P T; Öörni, K; Benitez, S; Ordoñez-Llanos, J

2015-11-01

Electronegative LDL (LDL(−)), a modified LDL fraction found in blood, induces the release of inflammatory mediators in endothelial cells and leukocytes. However, the inflammatory pathways activated by LDL(−) have not been fully defined. We aim to study whether LDL(−) induced release of the first-wave proinflammatory IL-1β in monocytes and monocyte-derived macrophages (MDM) and the mechanisms involved. LDL(−) was isolated from total LDL by anion exchange chromatography. Monocytes and MDM were isolated from healthy donors and stimulated with LDL(+) and LDL(−) (100 mg apoB/L). In monocytes, LDL(−) promoted IL-1β release in a time-dependent manner, obtaining at 20 h-incubation the double of IL-1β release induced by LDL(−) than by native LDL. LDL(−)-induced IL-1β release involved activation of the CD14-TLR4 receptor complex. LDL(−) induced priming, the first step of IL-1β release, since it increased the transcription of pro-IL-1β (8-fold) and NLRP3 (3-fold) compared to native LDL. Several findings show that LDL(−) induced inflammasome activation, the second step necessary for IL-1β release. Preincubation of monocytes with K+ channel inhibitors decreased LDL(−)-induced IL-1β release. LDL(−) induced formation of the NLRP3-ASC complex. LDL(−) triggered 2-fold caspase-1 activation compared to native LDL and IL-1β release was strongly diminished in the presence of the caspase-1 inhibitor Z-YVAD. In MDM, LDL(−) promoted IL-1β release, which was also associated with caspase-1 activation. LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation. By IL-1β release, LDL(−) could regulate inflammation in atherosclerosis.

Zinc release contributes to hypoglycemia-induced neuronal death.

PubMed

Suh, Sang Won; Garnier, Philippe; Aoyama, Koji; Chen, Yongmei; Swanson, Raymond A

2004-08-01

Neurons exposed to zinc exhibit activation of poly(ADP-ribose) polymerase-1 (PARP-1), an enzyme that normally participates in DNA repair but promotes cell death when extensively activated. Endogenous, vesicular zinc in brain is released to the extracellular space under conditions causing neuronal depolarization. Here, we used a rat model of insulin-induced hypoglycemia to assess the role of zinc release in PARP-1 activation and neuronal death after severe hypoglycemia. Zinc staining with N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ) showed depletion of presynaptic vesicular zinc from hippocampal mossy fiber terminals and accumulation of weakly bound zinc in hippocampal CA1 cell bodies after severe hypoglycemia. Intracerebroventricular injection of the zinc chelator calcium ethylene-diamine tetraacetic acid (CaEDTA) blocked the zinc accumulation and significantly reduced hypoglycemia-induced neuronal death. CaEDTA also attenuated the accumulation of poly(ADP-ribose), the enzymatic product of PARP-1, in hippocampal neurons. These results suggest that zinc translocation is an intermediary step linking hypoglycemia to PARP-1 activation and neuronal death.

Neutrophil-derived resistin release induced by Aggregatibacter actinomycetemcomitans.

PubMed

Furugen, Reiko; Hayashida, Hideaki; Yoshii, Yumiko; Saito, Toshiyuki

2011-08-01

Resistin is an adipokine that induces insulin resistance in mice. In humans, resistin is not produced in adipocytes, but in various leukocytes instead, and it acts as a proinflammatory molecule. The present investigation demonstrated high levels of resistin in culture supernatants of neutrophils that are stimulated by a highly leukotoxic strain of Aggregatibacter actinomycetemcomitans. In contrast, the level of resistin was remarkably low when neutrophils were exposed to two other strains that produce minimal levels of leukotoxin and a further isogenic mutant strain incapable of producing leukotoxin. Pretreatment of neutrophils with a monoclonal antibody to CD18, β chain of lymphocyte function-associated molecule 1 (LFA-1), or an Src family tyrosine kinase inhibitor before incubation with the highly leukotoxic strain inhibited the release of resistin. These results show that A. actinomycetemcomitans-expressed leukotoxin induces extracellular release of human neutrophil-derived resistin by interacting with LFA-1 on the surface of neutrophils and, consequently, activating Src family tyrosine kinases. 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

The dopamine beta-hydroxylase inhibitor nepicastat increases dopamine release and potentiates psychostimulant-induced dopamine release in the prefrontal cortex.

PubMed

Devoto, Paola; Flore, Giovanna; Saba, Pierluigi; Bini, Valentina; Gessa, Gian Luigi

2014-07-01

The dopamine-beta-hydroxylase inhibitor nepicastat has been shown to reproduce disulfiram ability to suppress the reinstatement of cocaine seeking after extinction in rats. To clarify its mechanism of action, we examined the effect of nepicastat, given alone or in association with cocaine or amphetamine, on catecholamine release in the medial prefrontal cortex and the nucleus accumbens, two key regions involved in the reinforcing and motivational effects of cocaine and in the reinstatement of cocaine seeking. Nepicastat effect on catecholamines was evaluated by microdialysis in freely moving rats. Nepicastat reduced noradrenaline release both in the medial prefrontal cortex and in the nucleus accumbens, and increased dopamine release in the medial prefrontal cortex but not in the nucleus accumbens. Moreover, nepicastat markedly potentiated cocaine- and amphetamine-induced extracellular dopamine accumulation in the medial prefrontal cortex but not in the nucleus accumbens. Extracellular dopamine accumulation produced by nepicastat alone or by its combination with cocaine or amphetamine was suppressed by the α2 -adrenoceptor agonist clonidine. It is suggested that nepicastat, by suppressing noradrenaline synthesis and release, eliminated the α2 -adrenoceptor mediated inhibitory mechanism that constrains dopamine release and cocaine- and amphetamine-induced dopamine release from noradrenaline or dopamine terminals in the medial prefrontal cortex. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

Ca2+ Entry is Required for Mechanical Stimulation-induced ATP Release from Astrocyte

PubMed Central

Lee, Jaekwang; Chun, Ye-Eun; Han, Kyung-Seok; Lee, Jungmoo; Woo, Dong Ho

2015-01-01

Astrocytes and neurons are inseparable partners in the brain. Neurotransmitters released from neurons activate corresponding G protein-coupled receptors (GPCR) expressed in astrocytes, resulting in release of gliotransmitters such as glutamate, D-serine, and ATP. These gliotransmitters in turn influence neuronal excitability and synaptic activities. Among these gliotransmitters, ATP regulates the level of network excitability and is critically involved in sleep homeostasis and astrocytic Ca2+ oscillations. ATP is known to be released from astrocytes by Ca2+-dependent manner. However, the precise source of Ca2+, whether it is Ca2+ entry from outside of cell or from the intracellular store, is still not clear yet. Here, we performed sniffer patch to detect ATP release from astrocyte by using various stimulation. We found that ATP was not released from astrocyte when Ca2+ was released from intracellular stores by activation of Gαq-coupled GPCR including PAR1, P2YR, and B2R. More importantly, mechanical stimulation (MS)-induced ATP release from astrocyte was eliminated when external Ca2+ was omitted. Our results suggest that Ca2+ entry, but not release from intracellular Ca2+ store, is critical for MS-induced ATP release from astrocyte. PMID:25792866

Iron Release from Soybean Seed Ferritin Induced by Cinnamic Acid Derivatives.

PubMed

Sha, Xuejiao; Chen, Hai; Zhang, Jingsheng; Zhao, Guanghua

2018-05-04

Plant ferritin represents a novel class of iron supplement, which widely co-exists with phenolic acids in a plant diet. However, there are few reports on the effect of these phenolic acids on function of ferritin. In this study, we demonstrated that cinnamic acid derivatives, as widely occurring phenolic acids, can induce iron release from holo soybean seed ferritin (SSF) in a structure-dependent manner. The ability of the iron release from SSF by five cinnamic acids follows the sequence of Cinnamic acid > Chlorogenic acid > Ferulic acid > p -Coumaric acid > Trans -Cinnamic acid. Fluorescence titration in conjunction with dialysis results showed that all of these five compounds have a similar, weak ability to bind with protein, suggesting that their protein-binding ability is not related to their iron release activity. In contrast, both Fe 2+ -chelating activity and reducibility of these cinnamic acid derivatives are in good agreement with their ability to induce iron release from ferritin. These studies indicate that cinnamic acid and its derivatives could have a negative effect on iron stability of holo soybean seed ferritin in diet, and the Fe 2+ -chelating activity and reducibility of cinnamic acid and its derivatives have strong relations to the iron release of soybean seed ferritin.

Exocrine and endocrine release of kallikrein after reflex-induced salivary secretion.

PubMed

Berg, T; Johansen, L; Poulsen, K

1990-05-01

Exocrine and endocrine release of rat submandibular gland kallikrein has been shown to be low after parasympathetic and beta-adrenergic stimulation but greatly increased after alpha-adrenergic stimulation. In the present study, release of glandular kallikrein was investigated under conditions known to give a reflex-induced salivary gland response. Heat stress induced a rich flow of saliva originating in the submandibular glands. Salivary kallikrein secretory rate was higher than after parasympathetic stimulation but lower than after sympathetic stimulation (P less than 0.005). Only heat stress increased circulating glandular kallikrein (12.7 +/- 0.8 ng ml-1 before heat exposure and 53.3 +/- 14.1 ng ml-1 40 min afterwards, P less than 0.005). There were no indications that the endocrine release of kallikrein was due to non-specific leakage. Atropine abolished heat-induced salivation and endocrine kallikrein secretion, possibly through interference with central pathways (P less than 0.05). However, phentolamine did not, which may indicate as an yet unidentified mediator of endogenous kallikrein release. The salivary gland response to acid and ether was comparable to that observed after parasympathetic nerve stimulation and was abolished by atropine (P less than 0.005). Stimuli known to influence other salivary gland ductal cells, such as aggression and starvation followed by drinking, also did not increase the plasma concentration of glandular kallikrein. The fact that various conditions which induce salivation did not increase circulating glandular kallikrein, coupled with the fact that kallikrein concentration was the highest in animals that died from heat stress, may suggest that the increase in circulating glandular kallikrein seen after heat stress may be pathological and could contribute to the development of heat shock.

Nitric oxide-induced calcium release: activation of type 1 ryanodine receptor by endogenous nitric oxide.

PubMed

Kakizawa, Sho; Yamazawa, Toshiko; Iino, Masamitsu

2013-01-01

Ryanodine receptors (RyRs), located in the sarcoplasmic/endoplasmic reticulum (SR/ER) membrane, are required for intracellular Ca2+ release that is involved in a wide range of cellular functions. In addition to Ca2+-induced Ca2+ release in cardiac cells and voltage-induced Ca2+ release in skeletal muscle cells, we recently identified another mode of intracellular Ca2+ mobilization mediated by RyR, i.e., nitric oxide-induced Ca2+ release (NICR), in cerebellar Purkinje cells. NICR is evoked by neuronal activity, is dependent on S-nitrosylation of type 1 RyR (RyR1) and is involved in the induction of long-term potentiation (LTP) of cerebellar synapses. In this addendum, we examined whether peroxynitrite, which is produced by the reaction of nitric oxide with superoxide, may also have an effect on the Ca2+ release via RyR1 and the cerebellar LTP. We found that scavengers of peroxynitrite have no significant effect either on the Ca2+ release via RyR1 or on the cerebellar LTP. We also found that an application of a high concentration of peroxynitrite does not reproduce neuronal activity-dependent Ca2+ release in Purkinje cells. These results support that NICR is induced by endogenous nitric oxide produced by neuronal activity through S-nitrosylation of RyR1.

Model Scramjet Inlet Unstart Induced by Mass Addition and Heat Release

NASA Astrophysics Data System (ADS)

Im, Seong-Kyun; Baccarella, Damiano; McGann, Brendan; Liu, Qili; Wermer, Lydiy; Do, Hyungrok

2015-11-01

The inlet unstart phenomena in a model scramjet are investigated at an arc-heated hypersonic wind tunnel. The unstart induced by nitrogen or ethylene jets at low or high enthalpy Mach 4.5 freestream flow conditions are compared. The jet injection pressurizes the downstream flow by mass addition and flow blockage. In case of the ethylene jet injection, heat release from combustion increases the backpressure further. Time-resolved schlieren imaging is performed at the jet and the lip of the model inlet to visualize the flow features during unstart. High frequency pressure measurements are used to provide information on pressure fluctuation at the scramjet wall. In both of the mass and heat release driven unstart cases, it is observed that there are similar flow transient and quasi-steady behaviors of unstart shockwave system during the unstart processes. Combustion driven unstart induces severe oscillatory flow motions of the jet and the unstart shock at the lip of the scramjet inlet after the completion of the unstart process, while the unstarted flow induced by solely mass addition remains relatively steady. The discrepancies between the processes of mass and heat release driven unstart are explained by flow choking mechanism.

Ursodeoxycholic acid inhibits TNFα-induced IL-8 release from monocytes.

PubMed

O'Dwyer, Aoife M; Lajczak, Natalia K; Keyes, Jennifer A; Ward, Joseph B; Greene, Catherine M; Keely, Stephen J

2016-08-01

Monocytes are critical to the pathogenesis of inflammatory bowel disease (IBD) as they infiltrate the mucosa and release cytokines that drive the inflammatory response. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid with anti-inflammatory actions, has been proposed as a potential new therapy for IBD. However, its effects on monocyte function are not yet known. Primary monocytes from healthy volunteers or cultured U937 monocytes were treated with either the proinflammatory cytokine, TNFα (5 ng/ml) or the bacterial endotoxin, lipopolysaccharide (LPS; 1 μg/ml) for 24 h, in the absence or presence of UDCA (25-100 μM). IL-8 release into the supernatant was measured by ELISA. mRNA levels were quantified by qPCR and changes in cell signaling proteins were determined by Western blotting. Toxicity was assessed by measuring lactate dehydrogenase (LDH) release. UDCA treatment significantly attenuated TNFα-, but not LPS-driven, release of IL-8 from both primary and cultured monocytes. UDCA inhibition of TNFα-driven responses was associated with reduced IL-8 mRNA expression. Both TNFα and LPS stimulated NFκB activation in monocytes, while IL-8 release in response to both cytokines was attenuated by an NFκB inhibitor, BMS-345541. Interestingly, UDCA inhibited TNFα-, but not LPS-stimulated, NFκB activation. Finally, TNFα, but not LPS, induced phosphorylation of TNF receptor associated factor (TRAF2), while UDCA cotreatment attenuated this response. We conclude that UDCA specifically inhibits TNFα-induced IL-8 release from monocytes by inhibiting TRAF2 activation. Since such actions would serve to dampen mucosal immune responses in vivo, our data support the therapeutic potential of UDCA for IBD. Copyright © 2016 the American Physiological Society.

Cortical cholinergic deficiency enhances amphetamine-induced dopamine release in the accumbens but not striatum.

PubMed

Mattsson, Anna; Olson, Lars; Svensson, Torgny H; Schilström, Björn

2007-11-01

Cholinergic dysfunction has been implicated as a putative contributing factor in the pathogenesis of schizophrenia. Recently, we showed that cholinergic denervation of the neocortex in adult rats leads to a marked increase in the behavioral response to amphetamine. The main objective of this study was to investigate if the enhanced locomotor response to amphetamine seen after cortical cholinergic denervation was paralleled by an increased amphetamine-induced release of dopamine in the nucleus accumbens and/or striatum. The corticopetal cholinergic projections were lesioned by intraparenchymal infusion of 192 IgG-saporin into the nucleus basalis magnocellularis of adult rats. Amphetamine-induced dopamine release in the nucleus accumbens or striatum was monitored by in vivo microdialysis 2 to 3 weeks after lesioning. We found that cholinergic denervation of the rat neocortex leads to a significantly increased amphetamine-induced dopamine release in the nucleus accumbens. Interestingly, the cholinergic lesion did not affect amphetamine-induced release of dopamine in the striatum. The enhanced amphetamine-induced dopamine release in the nucleus accumbens in the cholinergically denervated rats could be reversed by administration of the muscarinic agonist oxotremorine, but not nicotine, prior to the amphetamine challenge, suggesting that loss of muscarinic receptor stimulation is likely to have caused the observed effect. The results suggest that abnormal responsiveness of dopamine neurons can be secondary to cortical cholinergic deficiency. This, in turn, might be of relevance for the pathophysiology of schizophrenia and provides a possible link between cholinergic disturbances and alteration of dopamine transmission.

Tumor induces muscle wasting in mice through releasing extracellular Hsp70 and Hsp90.

PubMed

Zhang, Guohua; Liu, Zhelong; Ding, Hui; Zhou, Yong; Doan, Hoang Anh; Sin, Ka Wai Thomas; Zhu, Zhiren J; Flores, Rene; Wen, Yefei; Gong, Xing; Liu, Qingyun; Li, Yi-Ping

2017-09-19

Cachexia, characterized by muscle wasting, is a major contributor to cancer-related mortality. However, the key cachexins that mediate cancer-induced muscle wasting remain elusive. Here, we show that tumor-released extracellular Hsp70 and Hsp90 are responsible for tumor's capacity to induce muscle wasting. We detected high-level constitutive release of Hsp70 and Hsp90 associated with extracellular vesicles (EVs) from diverse cachexia-inducing tumor cells, resulting in elevated serum levels in mice. Neutralizing extracellular Hsp70/90 or silencing Hsp70/90 expression in tumor cells abrogates tumor-induced muscle catabolism and wasting in cultured myotubes and in mice. Conversely, administration of recombinant Hsp70 and Hsp90 recapitulates the catabolic effects of tumor. In addition, tumor-released Hsp70/90-expressing EVs are necessary and sufficient for tumor-induced muscle wasting. Further, Hsp70 and Hsp90 induce muscle catabolism by activating TLR4, and are responsible for elevation of circulating cytokines. These findings identify tumor-released circulating Hsp70 and Hsp90 as key cachexins causing muscle wasting in mice.Cachexia affects many cancer patients causing weight loss and increasing mortality. Here, the authors identify extracellular Hsp70 and Hsp90, either in soluble form or secreted as part of exosomes from tumor cells, to be responsible for tumor induction of cachexia.

RANKL release from self-assembling nanofiber hydrogels for inducing osteoclastogenesis in vitro.

PubMed

Xing, James Z; Lu, Lei; Unsworth, Larry D; Major, Paul W; Doschak, Michael R; Kaipatur, Neelambar R

2017-02-01

To develop a nanofiber hydrogel (NF-hydrogel) for sustained and controlled release of the recombinant receptor activator of NF-kB ligand; (RANKL) and to characterize the release kinetics and bioactivity of the released RANKL. Various concentrations of fluorescently-labelled RANKL protein were added to NF-hydrogels, composed of Acetyl-(Arg-Ala-Asp-Ala) 4 -CONH 2 [(RADA) 4 ] of different concentrations, to investigate the resulting in vitro release rates. The nano-structures of NF-hydrogel, with and without RANKL, were determined using atomic force microscopy (AFM). Released RANKL was further analyzed for changes in secondary and tertiary structure using CD spectroscopy and fluorescent emission spectroscopy, respectively. Bioactivity of released RANKL protein was determined using NFATc1 gene expression and tartrate resistant acid phosphatase (TRAP) activity of osteoclast cells as biomarkers. NF-hydrogel concentration dependent sustained release of RANKL protein was measured at concentrations between 0.5 and 2%(w/v). NF-hydrogel at 2%(w/v) concentration exhibited a sustained and slow-release of RANKL protein up to 48h. Secondary and tertiary structure analyses confirmed no changes to the RANKL protein released from NF-hydrogel in comparison to native RANKL. The results of NFATc1 gene mRNA expression and TRAP activities of osteoclast, showed that the release process did not affect the bioactivity of released RANKL. This novel study is the first of its kind to attempt in vitro characterization of NF-hydrogel based delivery of RANKL protein to induce osteoclastogenesis. We have shown the self-assembling NF-hydrogel peptide system is amenable to the sustained and controlled release of RANKL locally; that could in turn increase local concentration of RANKL to induce osteoclastogenesis, for application to the controlled mobilization of tooth movement in orthodontic procedures. Orthodontic tooth movement (OTM) occurs through controlled application of light forces to teeth

Baicalin Inhibits Haemophilus Parasuis-Induced High-Mobility Group Box 1 Release during Inflammation.

PubMed

Fu, Shulin; Liu, Huashan; Chen, Xiao; Qiu, Yinsheng; Ye, Chun; Liu, Yu; Wu, Zhongyuan; Guo, Ling; Hou, Yongqing; Hu, Chien-An Andy

2018-04-27

Haemophilus parasuis ( H. parasuis ) can cause Glässer’s disease in pigs. However, the molecular mechanism of the inflammation response induced by H. parasuis remains unclear. The high-mobility group box 1 (HMGB1) protein is related to the pathogenesis of various infectious pathogens, but little is known about whether H. parasuis can induce the release of HMGB1 in piglet peripheral blood monocytes. Baicalin displays important anti-inflammatory and anti-microbial activities. In the present study, we investigated whether H. parasuis can trigger the secretion of HMGB1 in piglet peripheral blood monocytes and the anti-inflammatory effect of baicalin on the production of HMGB1 in peripheral blood monocytes induced by H. parasuis during the inflammation response. In addition, host cell responses stimulated by H. parasuis were determined with RNA-Seq. The RNA-Seq results showed that H. parasuis infection provokes the expression of cytokines and the activation of numerous pathways. In addition, baicalin significantly reduced the release of HMGB1 in peripheral blood monocytes induced by H. parasuis . Taken together, our study showed that H. parasuis can induce the release of HMGB1 and baicalin can inhibit HMGB1 secretion in an H. parasuis -induced peripheral blood monocytes model, which may provide a new strategy for preventing the inflammatory disorders induced by H. parasuis .

Substance P-induced release of Met5-enkephalin from striatal and periaqueductal gray slices.

PubMed

Del Río, J; Naranjo, J R; Yang, H Y; Costa, E

1983-11-21

Substance P(SP), the heptapeptide SP and the stable analogue (p-Glu5-MePhe8-MeGly9) SP (DiMe-C7) induce a Ca2+-dependent release of Met5-enkephalin (MET) from slices of periaqueductal gray matter (PAG) and striatum of rats. The MET release from striatal slices is greater than that from PAG slices because of the higher MET content of striatum. Intraventricular injection of SP and of the two related peptides induce analgesia in the rat, and their analgesic potency is in line with their capacity to release MET. Other neuropeptides which possess antinociceptive activity such as bombesin, neurotensin, vasopressin and somatostatin fail to release MET from PAG slices.

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

NASA Astrophysics Data System (ADS)

Yang, Jianhua; Lu, Wenbo; Chen, Ming; Yan, Peng; Zhou, Chuangbing

2013-07-01

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time-energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.

Role of connexin43 hemichannels in mechanical stress-induced ATP release in human periodontal ligament cells.

PubMed

Luckprom, P; Kanjanamekanant, K; Pavasant, P

2011-10-01

Our previous studies showed that mechanical stress could induce ATP release in human periodontal ligament (HPDL) cells. By signaling through P2 purinergic receptors, ATP increased the expression and the synthesis of osteopontin and RANKL. In this study, the mechanism of stress-induced ATP release was investigated. Continuous compressive forces were applied on cultured HPDL cells. The ATP released was measured using luciferin-luciferase bioluminescence. The expression of gap-junction proteins was examined using RT-PCR and western blot analysis. The opening of hemichannels was demonstrated by cellular uptake of a fluorescent dye, 5(6)-carboxyfluorescein, which is known to penetrate hemichannels. Intracellular signal transduction was investigated using inhibitors and antagonists. Mechanical stress induced the release of ATP into the culture medium, which was attenuated by carbenoxolone, a nonspecific gap-junction inhibitor. Addition of meclofenamic acid sodium salt, a connexin43 inhibitor, inhibited ATP release by mechanical stress. Knockdown of connexin43 expression by small interfering RNA reduced the amount of ATP released by mechanical stress, suggesting the role of connexin43 hemichannels. In addition, intracellular Ca(2+) blockers could also inhibit mechanical stress-induced ATP release and the opening of the gap junction. Our study demonstrated the involvement of gap-junction hemichannels, especially connexin43, in the stress-induced ATP-release mechanism. Furthermore, this mechanism may be regulated by the intracellular Ca(2+) signaling pathway. These results suggest an important role of gap-junction hemichannels in the function and behavior of HPDL cells. © 2011 John Wiley & Sons A/S.

Gq-DREADD Selectively Initiates Glial Glutamate Release and Inhibits Cue-induced Cocaine Seeking

PubMed Central

Scofield Michael, D.; Boger Heather, A.; Smith Rachel, J.; Li, Hao; Haydon Philip, G.; Kalivas Peter, W.

2015-01-01

Background Glial cells of the central nervous system directly influence neuronal activity by releasing neuroactive small molecules, including glutamate. Long-lasting cocaine-induced reductions in extracellular glutamate in the nucleus accumbens core (NAcore) affect synaptic plasticity responsible for relapse vulnerability. Methods We transduced NAcore astrocytes with an AAV viral vector expressing hM3Dq (Gq) DREADD under control of the glial fibrillary acidic protein (GFAP) promoter in 62 male Sprague Dawley rats, 4 dnSNARE mice and 4 wild type littermates. Using glutamate biosensors we measured NAcore glutamate levels following intracranial or systemic administration of clozapine-N-oxide (CNO), and tested the ability of systemic CNO to inhibit reinstated cocaine or sucrose seeking following self-administration (SA) and extinction training. Results Administration of CNO in GFAP-Gq-DREADD transfected animals increased NAcore extracellular glutamate levels in vivo. The glial origin of released glutamate was validated by an absence of CNO-mediated release in mice expressing a dominant-negative SNARE variant in glia. Also, CNO-mediated release was relatively insensitive to N-type calcium channel blockade. Systemic administration of CNO inhibited cue-induced reinstatement of cocaine seeking in rats extinguished from cocaine, but not sucrose SA. The capacity to inhibit reinstated cocaine-seeking was prevented by systemic administration of the group II metabotropic glutamate receptor (mGluR2/3) antagonist LY341495. Conclusions DREADD-mediated glutamate gliotransmission inhibited cue-induced reinstatement of cocaine seeking by stimulating release-regulating mGluR2/3 autoreceptors to inhibit cue-induced synaptic glutamate spillover. PMID:25861696

Stretch-induced Ca2+ independent ATP release in hippocampal astrocytes.

PubMed

Xiong, Yingfei; Teng, Sasa; Zheng, Lianghong; Sun, Suhua; Li, Jie; Guo, Ning; Li, Mingli; Wang, Li; Zhu, Feipeng; Wang, Changhe; Rao, Zhiren; Zhou, Zhuan

2018-02-28

Similar to neurons, astrocytes actively participate in synaptic transmission via releasing gliotransmitters. The Ca 2+ -dependent release of gliotransmitters includes glutamate and ATP. Following an 'on-cell-like' mechanical stimulus to a single astrocyte, Ca 2+ independent single, large, non-quantal, ATP release occurs. Astrocytic ATP release is inhibited by either selective antagonist treatment or genetic knockdown of P2X7 receptor channels. Our work suggests that ATP can be released from astrocytes via two independent pathways in hippocampal astrocytes; in addition to the known Ca 2+ -dependent vesicular release, larger non-quantal ATP release depends on P2X7 channels following mechanical stretch. Astrocytic ATP release is essential for brain functions such as synaptic long-term potentiation for learning and memory. However, whether and how ATP is released via exocytosis remains hotly debated. All previous studies of non-vesicular ATP release have used indirect assays. By contrast, two recent studies report vesicular ATP release using more direct assays. In the present study, using patch clamped 'ATP-sniffer cells', we re-investigated astrocytic ATP release at single-vesicle resolution in hippocampal astrocytes. Following an 'on-cell-like' mechanical stimulus of a single astrocyte, a Ca 2+ independent single large non-quantal ATP release occurred, in contrast to the Ca 2+ -dependent multiple small quantal ATP release in a chromaffin cell. The mechanical stimulation-induced ATP release from an astrocyte was inhibited by either exposure to a selective antagonist or genetic knockdown of P2X7 receptor channels. Functional P2X7 channels were expressed in astrocytes in hippocampal brain slices. Thus, in addition to small quantal ATP release, larger non-quantal ATP release depends on P2X7 channels in astrocytes. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Properties of Ca2+ release induced by clofibric acid from the sarcoplasmic reticulum of mouse skeletal muscle fibres

PubMed Central

Ikemoto, Takaaki; Endo, Makoto

2001-01-01

To characterize the effect of clofibric acid (Clof) on the Ca2+ release mechanism in the sarcoplasmic reticulum (SR) of skeletal muscle, we analysed the properties of Clof-induced Ca2+ release under various conditions using chemically skinned skeletal muscle fibres of the mouse.Clof (>0.5 mM) released Ca2+ from the SR under Ca2+-free conditions buffered with 10 mM EGTA (pCa >8).Co-application of ryanodine and Clof at pCa >8 but not ryanodine alone reduced the Ca2+ uptake capacity of the SR. Thus, Ca2+ release induced by Clof at pCa >8 must be a result of the activation of the ryanodine receptor (RyR).At pCa >8, (i) Clof-induced Ca2+ release was inhibited by adenosine monophosphate (AMP), (ii) the inhibitory effect of Mg2+ on the Clof-induced Ca2+ release was saturated at about 1 mM, and (iii) Clof-induced Ca2+ release was not inhibited by procaine (10 mM). These results indicate that Clof may activate the RyR-Ca2+ release channels in a manner different from Ca2+-induced Ca2+ release (CICR).In addition to this unique mode of opening, Clof also enhanced the CICR mode of opening of RyR-Ca2+ release channels.Apart from CICR, a high concentration of Ca2+ might also enhance the unique mode of opening by Clof.These results suggest that some features of Ca2+ release activated by Clof are similar to those of physiological Ca2+ release (PCR) in living muscle cells and raise the possibility that Clof may be useful in elucidating the mechanism of PCR in skeletal muscle. PMID:11606311

Methamphetamine induces the release of endothelin.

PubMed

Seo, Jeong-Woo; Jones, Susan M; Hostetter, Trisha A; Iliff, Jeffrey J; West, G Alexander

2016-02-01

Methamphetamine is a potent psychostimulant drug of abuse that increases release and blocks reuptake of dopamine, producing intense euphoria, factors that may contribute to its widespread abuse. It also produces severe neurotoxicity resulting from oxidative stress, DNA damage, blood-brain barrier disruption, microgliosis, and mitochondrial dysfunction. Intracerebral hemorrhagic and ischemic stroke have been reported after intravenous and oral abuse of methamphetamine. Several studies have shown that methamphetamine causes vasoconstriction of vessels. This study investigates the effect of methamphetamine on endothelin-1 (ET-1) release in mouse brain endothelial cells by ELISA. ET-1 transcription as well as endothelial nitric oxide synthase (eNOS) activation and transcription were measured following methamphetamine treatment. We also examine the effect of methamphetamine on isolated cerebral arteriolar vessels from C57BL/6 mice. Penetrating middle cerebral arterioles were cannulated at both ends with a micropipette system. Methamphetamine was applied extraluminally, and the vascular response was investigated. Methamphetamine treatment of mouse brain endothelial cells resulted in ET-1 release and a transient increase in ET-1 message. The activity and transcription of eNOS were only slightly enhanced after 24 hr of treatment with methamphetamine. In addition, methamphetamine caused significant vasoconstriction of isolated mouse intracerebral arterioles. The vasoconstrictive effect of methamphetamine was attenuated by coapplication of the endothelin receptor antagonist PD145065. These findings suggest that vasoconstriction induced by methamphetamine is mediated through the endothelin receptor and may involve an endothelin-dependent pathway. © 2015 Wiley Periodicals, Inc.

Antibiotic-induced bacterial killing stimulates tumor necrosis factor-alpha release in whole blood.

PubMed

Arditi, M; Kabat, W; Yogev, R

1993-01-01

Rapid lysis of gram-negative bacteria is associated with considerable release of free endotoxin. Production of tumor necrosis factor (TNF) from adult whole blood ex vivo in response to bacterial products generated during antibiotic killing of Haemophilus influenzae type b (Hib) was investigated. Heparinized whole blood released TNF in a dose-dependent fashion in response to purified lipooligosaccharide of Hib. Bacteria (10(4)-10(7) cfu/mL) were placed into a Transwell filter insert (0.1 microns) and incubated with whole blood in the presence of various antibiotics. Exposure to ceftriaxone resulted in significantly greater release of TNF during killing of Hib than did exposure to imipenem, despite similar degrees of bacterial killing at 6 h. Polymyxin B inhibited the ceftriaxone-induced TNF release by 97%-99%, indicating that free endotoxin was the predominant stimulus for the increase in TNF release in this system. These observations suggest that ceftriaxone-induced killing of Hib results in bacterial cell wall products that are more proinflammatory than those produced by imipenem.

Lateralized sex differences in stress-induced dopamine release in the rat.

PubMed

Sullivan, Ron M; Dufresne, Marc M; Waldron, Jay

2009-02-18

This study examined the possibility that hemispheric differences in stress-induced brain activation vary as a function of sex. Using in-vivo voltammetry, increases in extracellular dopamine release in response to predator odour and tail pinch stress were recorded bilaterally and simultaneously in either the infralimbic cortex or basolateral amygdala. In both stress-sensitive brain regions, significant sex x hemisphere interactions were observed, with males and females showing greater dopamine activation in right-brain and left-brain structures, respectively. Cortical asymmetries in dopamine release also showed sex-specific correlations with stress-induced neuroendocrine activation. Given the intriguing human parallels, we suggest that differential cerebral lateralization may be highly relevant to the disproportionately high incidence of stress-related disorders such as depression and anxiety seen in women.

Stress-induced release of GUT peptides in young women classified as restrained or unrestrained eaters.

PubMed

Hilterscheid, Esther; Laessle, Reinhold

2015-12-01

Basal release of GUT peptides has been found to be altered in restrained eaters. Stress-induced secretion, however, has not yet been described, but could be a biological basis of overeating that exposes restrained eaters to a higher risk of becoming obese. The aim of the present study was to compare restrained and unrestrained eaters with respect to stress-induced release of the GUT peptides ghrelin and PYY. 46 young women were studied. Blood sampling for peptides was done before and after the Trier Social Stress Test. Ghrelin secretion after stress was significantly elevated in the restrained eaters, whereas no significant differences were detected for PYY. Stress-induced release of GUT peptides can be interpreted as a cause as well as a consequence of restrained eating.

Endurance exercise modulates levodopa induced growth hormone release in patients with Parkinson's disease.

PubMed

Müller, Thomas; Welnic, Jacub; Woitalla, Dirk; Muhlack, Siegfried

2007-07-11

Acute levodopa (LD) application and exercise release human growth hormone (GH). An earlier trial showed, that combined stimulus of exercise and LD administration is the best provocative test for GH response in healthy participants. Objective was to show this combined effect of LD application and exercise on GH response and to investigate the impact on LD metabolism in 20 previously treated patients with Parkinson's disease (PD). We measured GH- and LD plasma concentrations following soluble 200 mg LD/50 mg benserazide administration during endurance exercise and rest on two separate consecutive days. GH concentrations significantly increased on both days, but GH release was significantly delayed during rest. LD metabolism was not altered due to exercise in a clinical relevant manner. Exercise induced a significant faster LD stimulated GH release in comparison with the rest condition. We did not find the supposed increase of LD induced GH release by endurance exercise. We assume, that only a limited amount of GH is available for GH release in the anterior pituitary following an acute 200 mg LD administration. GH disposal also depends on growth hormone releasing hormone (GHRH), which is secreted into hypothalamic portal capillaries. During the exercise condition, the resulting higher blood pressure supports blood flow and thus GHRH transport towards the GH producing cells in the pituitary. This might additionally have caused the significant faster GH release during exercise.

Saturated fatty acid palmitate induces extracellular release of histone H3: A possible mechanistic basis for high-fat diet-induced inflammation and thrombosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shrestha, Chandan; Department of Laboratory and Vascular Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima; Ito, Takashi

Highlights: •High-fat diet feeding and palmitate induces the release of nuclear protein histone H3. •ROS production and JNK signaling mediates the release of histone H3. •Extracellular histones induces proinflammatory and procoagulant response. -- Abstract: Chronic low-grade inflammation is a key contributor to high-fat diet (HFD)-related diseases, such as type 2 diabetes, non-alcoholic steatohepatitis, and atherosclerosis. The inflammation is characterized by infiltration of inflammatory cells, particularly macrophages, into obese adipose tissue. However, the molecular mechanisms by which a HFD induces low-grade inflammation are poorly understood. Here, we show that histone H3, a major protein component of chromatin, is released into themore » extracellular space when mice are fed a HFD or macrophages are stimulated with the saturated fatty acid palmitate. In a murine macrophage cell line, RAW 264.7, palmitate activated reactive oxygen species (ROS) production and JNK signaling. Inhibitors of these pathways dampened palmitate-induced histone H3 release, suggesting that the extracellular release of histone H3 was mediated, in part, through ROS and JNK signaling. Extracellular histone activated endothelial cells toexpress the adhesion molecules ICAM-1 and VCAM-1 and the procoagulant molecule tissue factor, which are known to contribute to inflammatory cell recruitment and thrombosis. These results suggest the possible contribution of extracellular histone to the pathogenesis of HFD-induced inflammation and thrombosis.« less

Shear-induced integrin signaling in platelet phosphatidylserine exposure, microvesicle release and coagulation.

PubMed

Pang, Aiming; Cui, Yujie; Chen, Yunfeng; Cheng, Ni; Delaney, M Keegan; Gu, Minyi; Stojanovic-Terpo, Aleksandra; Zhu, Cheng; Du, Xiaoping

2018-05-31

It is currently unclear why agonist-stimulated platelets require shear force to efficiently externalize the procoagulant phospholipid phosphatidylserine (PS) and release PS-exposed microvesicles (MVs). We reveal that integrin outside-in signaling is an important mechanism for this requirement. PS exposure and MV release were inhibited in β 3 -/- platelets or by integrin antagonists. The impaired MV release and PS exposure in β 3 -/- platelets were rescued by expressing wild type β 3 but not a Gα 13 binding-deficient β 3 mutant (E 733 EE to AAA), which blocks outside-in signaling but not ligand binding. Inhibition of Gα 13 or Src also diminished agonist/shear-dependent PS exposure and MV release, further indicating a role for integrin outside-in signaling. PS exposure in activated platelets was induced by application of pulling force via an integrin ligand, which was abolished by inhibiting Gα 13 -integrin interaction, suggesting that GGα 13 -dependent transmission of mechanical signals by integrins induces PS exposure. Inhibition of Gα 13 delayed coagulation in vitro. Furthermore, inhibition or platelet-specific knockout of Gα 13 diminished laser-induced intravascular fibrin formation in arterioles in vivo. Thus, β 3 integrins serve as a shear sensor activating the Gα 13 -dependent outside-in signaling pathway to facilitate platelet procoagulant function. Pharmacological targeting of Gα 13 -integrin interaction prevents occlusive thrombosis in vivo by inhibiting both coagulation and platelet thrombus formation. Copyright © 2018 American Society of Hematology.

A new NO donor failed to release NO and to induce relaxation in the rat basilar artery.

PubMed

Paulo, Michele; Rodrigues, Gerson J; da Silva, Roberto S; Bendhack, Lusiane M

2012-02-14

Nitric oxide (NO)-donors are pharmacologically active substances that in vivo or in vitro release NO. Their most common side effect is headache caused by cerebral vasodilatation. We previously demonstrated that the new NO-donor Ru(terpy)(bdq)NO](3+) (Terpy), synthesized in our laboratory, induces relaxation of rat aorta. This study aimed to verify the effect of Terpy and sodium nitroprusside (SNP) in basilar artery. We conducted vascular reactivity experiments on endothelium-denuded basilar rings. The concentrations of iron (Fe) and ruthenium (Ru) complex were analyzed in basilar artery lysates after incubation with NO donors by mass spectrometry. We also evaluated the NO released from SNP and Terpy by using confocal microscopy. Interestingly, Terpy did not induce relaxation of the basilar artery. SNP induced relaxation in a concentration-dependent way. NO donors cross the membrane of vascular smooth muscle and entered the cell. In spite of its permeability, Terpy did not release NO in the basilar artery. Otherwise, SNP released NO in the basilar artery cells cytoplasm. Taken together, our results demonstrate that the new NO donor (Terpy) failed to release NO and to induce relaxation in the basilar artery. The NO donor SNP induces vascular relaxation due to NO release in the vascular smooth muscle cells. Copyright © 2011 Elsevier B.V. All rights reserved.

GTP requirement for inositol-1,4,5-trisphosphate-induced Ca2+ release from sarcoplasmic reticulum in smooth muscle.

PubMed

Saida, K; van Breemen, C

1987-05-14

We have examined inositol-1,4,5-trisphosphate (IP3)-induced Ca2+ release from the sarcoplasmic reticulum (SR) in the skinned vascular smooth muscle. The amount of Ca2+ in the SR was estimated indirectly by caffeine-induced contraction of the skinned preparation. The Ca2+ release from the SR by IP3 required GTP. A non-hydrolyzable analogue of GTP, guanosine 5'-(beta gamma-imido) triphosphate (GppNHp) could substitute for GTP in the IP3-induced Ca2+ release. These results suggest an involvement of GTP-binding protein in the mechanism of Ca2+ release from the SR by IP3 in smooth muscle.

Ristocetin induces phosphorylated-HSP27 (HSPB1) release from the platelets of type 2 DM patients: Anti-platelet agent-effect on the release.

PubMed

Tokuda, Haruhiko; Kuroyanagi, Gen; Onuma, Takashi; Enomoto, Yukiko; Doi, Tomoaki; Iida, Hiroki; Otsuka, Takanobu; Ogura, Shinji; Iwama, Toru; Kojima, Kumi; Kozawa, Osamu

2018-04-01

It has been previously reported that HSP27 is released from platelets in type 2 diabetes mellitus (DM) patients according to phosphorylation. In the present study, we investigated the effect of ristocetin, a glycoprotein (GP)Ib/IX/V activator, on the release of HSP27 and the effect of anti-platelet agents, such as acetylsalicylic acid (ASA), on this release. Forty-six patients with type 2 DM were recruited, and classified into two groups depending on administration of anti-platelet agents, resulting in 31 patients without these agents (control group) and 15 patients with them (anti-platelet group). Ristocetin potently induced the aggregation of platelets in the two groups. Ristocetin-induced changes of the area under the curve of light transmittance and the ratio of the size of platelet aggregates in the anti-platelet group were slightly different from those in the control group. On the other hand, the levels of phosphorylated-HSP27 induced by ristocetin in the platelets from a patient of the anti-platelet group taking ASA were significantly lower than those from a patient of the control group. The levels of HSP27 release from the ristocetin-stimulated platelets were significantly correlated with the levels of phosphorylated-HSP27 in the platelets from patients in the two groups. The levels of HSP27 release and those of platelet-derived growth factor-AB (PDGF-AB) secretion stimulated by ristocetin in the anti-platelet group were lower than those in the control group. In addition, the levels of HSP27 release and those of PDGF-AB secretion stimulated by ADP in the anti-platelet group were lower than those in the control group. These results strongly suggest that anti-platelet agents inhibit the HSP27 release from platelets stimulated by ristocetin but not the aggregation in type 2 DM patients.

Near-Infrared-Induced Heating of Confined Water in Polymeric Particles for Efficient Payload Release

PubMed Central

2015-01-01

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution. PMID:24717072

Near-infrared-induced heating of confined water in polymeric particles for efficient payload release.

PubMed

Viger, Mathieu L; Sheng, Wangzhong; Doré, Kim; Alhasan, Ali H; Carling, Carl-Johan; Lux, Jacques; de Gracia Lux, Caroline; Grossman, Madeleine; Malinow, Roberto; Almutairi, Adah

2014-05-27

Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution.

Vitamin D Reduces Oxidative Stress-Induced Procaspase-3/ROCK1 Activation and MP Release by Placental Trophoblasts.

PubMed

Xu, Jie; Jia, Xiuyue; Gu, Yang; Lewis, David F; Gu, Xin; Wang, Yuping

2017-06-01

Increased microparticle (MP) shedding by placental trophoblasts contributes to maternal vascular inflammatory response and endothelial dysfunction in preeclampsia. Vitamin D has beneficial effects in pregnancy; however, its effect on trophoblast MP release has not been investigated. To investigate if vitamin D could protect trophoblasts from oxidative stress-induced MP release. Placental trophoblasts were isolated from uncomplicated and preeclamptic placentas. Effects of vitamin D on MP release induced by oxidative stress inducer CoCl2 were studied. Annexin V+ MPs were assessed by flow cytometry. Expression of caveolin-1, endothelial nitric oxide synthase (eNOS), procaspase-3, cleaved caspase-3, and Rho-associated coiled-coil protein kinase 1 (ROCK1) in trophoblasts and trophoblast-derived MPs were determined by Western blot. Trophoblasts from preeclamptic pregnancies released significantly more MPs than cells from uncomplicated pregnancies (P < 0.01). CoCl2-induced increase in MP release was associated with upregulation of caveolin-1 and downregulation of eNOS expression in trophoblasts (P < 0.05), which could be attenuated by 1,25(OH)2D3. Moreover, 1,25(OH)2D3 could also inhibit CoCl2-induced procaspase-3 cleavage and ROCK1 activation in trophoblasts. Consistently, CoCl2-induced upregulation of procaspase-3, cleaved caspase-3, and ROCK1 expression in trophoblast-derived MPs were also reduced in cells treated with 1,25(OH)2D3. Placental trophoblasts from preeclamptic pregnancies released more MP than cells from uncomplicated pregnancies. Oxidative stress-induced increase in MP shedding is associated with upregulation of caveolin-1 and downregulation of eNOS expression in placental trophoblasts. Inhibition of caspase-3 cleavage and ROCK1 activation, together with upregulation of eNOS expression, could be the potential cellular/molecular mechanism(s) of vitamin D protective effects on placental trophoblasts. Copyright © 2017 Endocrine Society

Type-3 ryanodine receptors mediate hypoxia-, but not neurotransmitter-induced calcium release and contraction in pulmonary artery smooth muscle cells.

PubMed

Zheng, Yun-Min; Wang, Qing-Song; Rathore, Rakesh; Zhang, Wan-Hui; Mazurkiewicz, Joseph E; Sorrentino, Vincenzo; Singer, Harold A; Kotlikoff, Michael I; Wang, Yong-Xiao

2005-04-01

In this study we examined the expression of RyR subtypes and the role of RyRs in neurotransmitter- and hypoxia-induced Ca2+ release and contraction in pulmonary artery smooth muscle cells (PASMCs). Under perforated patch clamp conditions, maximal activation of RyRs with caffeine or inositol triphosphate receptors (IP3Rs) with noradrenaline induced equivalent increases in [Ca2+]i and Ca2+-activated Cl- currents in freshly isolated rat PASMCs. Following maximal IP3-induced Ca2+ release, neither caffeine nor chloro-m-cresol induced a response, whereas prior application of caffeine or chloro-m-cresol blocked IP3-induced Ca2+ release. In cultured human PASMCs, which lack functional expression of RyRs, caffeine failed to affect ATP-induced increases in [Ca2+]i in the presence and absence of extracellular Ca2+. The RyR antagonists ruthenium red, ryanodine, tetracaine, and dantrolene greatly inhibited submaximal noradrenaline- and hypoxia-induced Ca2+ release and contraction in freshly isolated rat PASMCs, but did not affect ATP-induced Ca2+ release in cultured human PASMCs. Real-time quantitative RT-PCR and immunofluorescence staining indicated similar expression of all three RyR subtypes (RyR1, RyR2, and RyR3) in freshly isolated rat PASMCs. In freshly isolated PASMCs from RyR3 knockout (RyR3-/-) mice, hypoxia-induced, but not submaximal noradrenaline-induced, Ca2+ release and contraction were significantly reduced. Ruthenium red and tetracaine can further inhibit hypoxic increase in [Ca2+]i in RyR3-/- mouse PASMCs. Collectively, our data suggest that (a) RyRs play an important role in submaximal noradrenaline- and hypoxia-induced Ca2+ release and contraction; (b) all three subtype RyRs are expressed; and (c) RyR3 gene knockout significantly inhibits hypoxia-, but not submaximal noradrenaline-induced Ca2+ and contractile responses in PASMCs.

Injection-induced moment release can also be aseismic

USGS Publications Warehouse

McGarr, Arthur; Barbour, Andrew J.

2018-01-01

The cumulative seismic moment is a robust measure of the earthquake response to fluid injection for injection volumes ranging from 3100 to about 12 million m3. Over this range, the moment release is limited to twice the product of the shear modulus and the volume of injected fluid. This relation also applies at the much smaller injection volumes of the field experiment in France reported by Guglielmi, et al. (2015) and laboratory experiments to simulate hydraulic fracturing described by Goodfellow, et al. (2015). In both of these studies, the relevant moment release for comparison with the fluid injection was aseismic and consistent with the scaling that applies to the much larger volumes associated with injection-induced earthquakes with magnitudes extending up to 5.8. Neither the micro-earthquakes, at the site in France, nor the acoustic emission in the laboratory samples contributed significantly to the deformation due to fluid injection.

Lidocaine attenuates anisomycin-induced amnesia and release of norepinephrine in the amygdala

PubMed Central

Sadowski, Renee N.; Canal, Clint E.; Gold, Paul E.

2011-01-01

When administered near the time of training, protein synthesis inhibitors such as anisomycin impair later memory. A common interpretation of these findings is that memory consolidation requires new protein synthesis initiated by training. However, recent findings support an alternative interpretation that abnormally large increases in neurotransmitter release after injections of anisomycin may be responsible for producing amnesia. In the present study, a local anesthetic was administered prior to anisomycin injections in an attempt to mitigate neurotransmitter actions and thereby attenuate the resulting amnesia. Rats received lidocaine and anisomycin injections into the amygdala 130 and 120 min, respectively, prior to inhibitory avoidance training. Memory tests 48 hr later revealed that lidocaine attenuated anisomycin-induced amnesia. In other rats, in vivo microdialysis was performed at the site of amygdala infusion of lidocaine and anisomycin. As seen previously, anisomycin injections produced large increases in release of norepinephrine in the amygdala. Lidocaine attenuated the anisomycin-induced increase in release of norepinephrine but did not reverse anisomycin inhibition of protein synthesis, as assessed by c-Fos immunohistochemistry. These findings are consistent with past evidence suggesting that anisomycin causes amnesia by initiating abnormal release of neurotransmitters in response to the inhibition of protein synthesis. PMID:21453778

Cocaine cue–induced dopamine release in the human prefrontal cortex

PubMed Central

Milella, Michele S.; Fotros, Aryandokht; Gravel, Paul; Casey, Kevin F.; Larcher, Kevin; Verhaeghe, Jeroen A.J.; Cox, Sylvia M.L.; Reader, Andrew J.; Dagher, Alain; Benkelfat, Chawki; Leyton, Marco

2016-01-01

Background Accumulating evidence indicates that drug-related cues can induce dopamine (DA) release in the striatum of substance abusers. Whether these same cues provoke DA release in the human prefrontal cortex remains unknown. Methods We used high-resolution positron emission tomography with [18F]fallypride to measure cortical and striatal DA D2/3 receptor availability in the presence versus absence of drug-related cues in volunteers with current cocaine dependence. Results Twelve individuals participated in our study. Among participants reporting a craving response (9 of 12), exposure to the cocaine cues significantly decreased [18F]fallypride binding potential (BPND) values in the medial orbitofrontal cortex and striatum. In all 12 participants, individual differences in the magnitude of craving correlated with BPND changes in the medial orbitofrontal cortex, dorsolateral prefrontal cortex, anterior cingulate, and striatum. Consistent with the presence of autoreceptors on mesostriatal but not mesocortical DA cell bodies, midbrain BPND values were significantly correlated with changes in BPND within the striatum but not the cortex. The lower the midbrain D2 receptor levels, the greater the striatal change in BPND and self-reported craving. Limitations Limitations of this study include its modest sample size, with only 2 female participants. Newer tracers might have greater sensitivity to cortical DA release. Conclusion In people with cocaine use disorders, the presentation of drug-related cues induces DA release within cortical and striatal regions. Both effects are associated with craving, but only the latter is regulated by midbrain autoreceptors. Together, the results suggest that cortical and subcortical DA responses might both influence drug-focused incentive motivational states, but with separate regulatory mechanisms. PMID:26900792

Cocaine cue-induced dopamine release in the human prefrontal cortex.

PubMed

Milella, Michele S; Fotros, Aryandokht; Gravel, Paul; Casey, Kevin F; Larcher, Kevin; Verhaeghe, Jeroen A J; Cox, Sylvia M L; Reader, Andrew J; Dagher, Alain; Benkelfat, Chawki; Leyton, Marco

2016-08-01

Accumulating evidence indicates that drug-related cues can induce dopamine (DA) release in the striatum of substance abusers. Whether these same cues provoke DA release in the human prefrontal cortex remains unknown. We used high-resolution positron emission tomography with [18F]fallypride to measure cortical and striatal DA D2/3 receptor availability in the presence versus absence of drug-related cues in volunteers with current cocaine dependence. Twelve individuals participated in our study. Among participants reporting a craving response (9 of 12), exposure to the cocaine cues significantly decreased [18F]fallypride binding potential (BPND) values in the medial orbitofrontal cortex and striatum. In all 12 participants, individual differences in the magnitude of craving correlated with BPND changes in the medial orbitofrontal cortex, dorsolateral prefrontal cortex, anterior cingulate, and striatum. Consistent with the presence of autoreceptors on mesostriatal but not mesocortical DA cell bodies, midbrain BPND values were significantly correlated with changes in BPND within the striatum but not the cortex. The lower the midbrain D2 receptor levels, the greater the striatal change in BPND and self-reported craving. Limitations of this study include its modest sample size, with only 2 female participants. Newer tracers might have greater sensitivity to cortical DA release. In people with cocaine use disorders, the presentation of drug-related cues induces DA release within cortical and striatal regions. Both effects are associated with craving, but only the latter is regulated by midbrain autoreceptors. Together, the results suggest that cortical and subcortical DA responses might both influence drug-focused incentive motivational states, but with separate regulatory mechanisms.

Corticotropin-Releasing Factor Mediates Pain-Induced Anxiety through the ERK1/2 Signaling Cascade in Locus Coeruleus Neurons

PubMed Central

Borges, Gisela Patrícia; Micó, Juan Antonio; Neto, Fani Lourença

2015-01-01

Background: The corticotropin-releasing factor is a stress-related neuropeptide that modulates locus coeruleus activity. As locus coeruleus has been involved in pain and stress-related patologies, we tested whether the pain-induced anxiety is a result of the corticotropin-releasing factor released in the locus coeruleus. Methods: Complete Freund’s adjuvant-induced monoarthritis was used as inflammatory chronic pain model. α-Helical corticotropin-releasing factor receptor antagonist was microinjected into the contralateral locus coeruleus of 4-week-old monoarthritic animals. The nociceptive and anxiety-like behaviors, as well as phosphorylated extracellular signal-regulated kinases 1/2 and corticotropin-releasing factor receptors expression, were quantified in the paraventricular nucleus and locus coeruleus. Results: Monoarthritic rats manifested anxiety and increased phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus and paraventricular nucleus, although the expression of corticotropin-releasing factor receptors was unaltered. α-Helical corticotropin-releasing factor antagonist administration reversed both the anxiogenic-like behavior and the phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus. Conclusions: Pain-induced anxiety is mediated by corticotropin-releasing factor neurotransmission in the locus coeruleus through extracellular signal-regulated kinases 1/2 signaling cascade. PMID:25716783

Adenosine triphosphate induces P2Y2 activation and interleukin-8 release in human esophageal epithelial cells.

PubMed

Wu, Liping; Oshima, Tadayuki; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

2017-07-01

Immune-mediated mucosal inflammation characterized by the release of interleukin (IL)-8 is associated with gastroesophageal reflux disease. ATP released by human esophageal epithelial cells (HEECs) mediates the release of cytokines through P2 nucleotide receptors that are present on various cells, including HEECs. This study characterized and identified human esophageal epithelial P2 receptors that are responsible for ATP-mediated release of IL-8 by using a human esophageal stratified squamous epithelial model. Primary HEECs were cultured with the use of an air-liquid interface (ALI) system. The ATP analogue adenosine 5'-O-3-thiotriphosphate (ATP-γ-S) was added to the basolateral compartment, and IL-8 release was measured. Involvement of the P2Y2 receptor was assessed with the use of selective and non-selective receptor antagonists and a P2Y2 receptor agonist. Expression of the P2Y2 receptor was assessed using western blotting and immunohistochemistry. Adenosine triphosphate-γ-S induced IL-8 release through the P2Y2 receptor. A P2Y2 receptor antagonist but not a P2X3 receptor antagonist or a P2Y1 receptor antagonist blocked ATP-γ-S-mediated IL-8 release. Conversely, a P2Y2 receptor agonist induced IL-8 release. Western blotting and immunohistochemistry of the P2Y2 receptor showed strong expression of the P2Y2 receptor on ALI-cultured HEECs and in human esophagus. Inhibition of extracellular signal-regulated kinase but not of protein kinase C blocked the ATP-mediated release of IL-8. ATP-γ-S induced phosphorylation of extracellular signal-regulated kinase, and a P2Y2 receptor antagonist blocked this phosphorylation. Interleukin-8 release after purinergic stimulation in ALI-cultured HEECs is mediated through P2Y2 receptor activation. ATP-induced IL-8 release maybe involved in the pathogenesis of refractory gastroesophageal reflux disease. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Hypotonic swelling promotes nitric oxide release in cardiac ventricular myocytes: impact on swelling-induced negative inotropic effect

PubMed Central

Gonano, Luis Alberto; Morell, Malena; Burgos, Juan Ignacio; Dulce, Raul Ariel; De Giusti, Verónica Celeste; Aiello, Ernesto Alejandro; Hare, Joshua Michael; Vila Petroff, Martin

2014-01-01

Aims Cardiomyocyte swelling occurs in multiple pathological situations and has been associated with contractile dysfunction, cell death, and enhanced propensity to arrhythmias. We investigate whether hypotonic swelling promotes nitric oxide (NO) release in cardiomyocytes, and whether it impacts on swelling-induced contractile dysfunction. Methods and results Superfusing rat cardiomyocytes with a hypotonic solution (HS; 217 mOsm), increased cell volume, reduced myocyte contraction and Ca2+ transient, and increased NO-sensitive 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM) fluorescence. When cells were exposed to HS + 2.5 mM of the NO synthase inhibitor l-NAME, cell swelling occurred in the absence of NO release. Swelling-induced NO release was also prevented by the nitric oxide synthase 1 (NOS1) inhibitor, nitroguanidine, and significantly reduced in NOS1 knockout mice. Additionally, colchicine (inhibitor of microtubule polymerization) prevented the increase in DAF-FM fluorescence induced by HS, indicating that microtubule integrity is necessary for swelling-induced NO release. The swelling-induced negative inotropic effect was exacerbated in the presence of either l-NAME, nitroguandine, the guanylate cyclase inhibitor, ODQ, or the PKG inhibitor, KT5823, suggesting that NOS1-derived NO provides contractile support via a cGMP/PKG-dependent mechanism. Indeed, ODQ reduced Ca2+ wave velocity and both ODQ and KT5823 reduced the HS-induced increment in ryanodine receptor (RyR2, Ser2808) phosphorylation, suggesting that in this context, cGMP/PKG may contribute to preserve contractile function by enhancing sarcoplasmic reticulum Ca2+ release. Conclusions Our findings suggest a novel mechanism for NO release in cardiomyocytes with putative pathophysiological relevance determined, at least in part, by its capability to reduce the extent of contractile dysfunction associated with hypotonic swelling. PMID:25344365

Delivery of fullerene-containing complexes via microgel swelling and shear-induced release.

PubMed

Tarabukina, Elena; Zoolshoev, Zoolsho; Melenevskaya, Elena; Budtova, Tatiana

2010-01-15

The absorption and release of poly(vinylpyrrolidone)-fullerene C60 complexes (PVP/C60) from a model microgel is studied. A dry microgel based on a chemically cross-linked sodium polyacrylate was swollen in the aqueous solutions of complexes which were afterwards released under shear stress. First, gel swelling degree in static conditions in the excess of PVP/C60 solutions was studied: the degree of swelling decreases with the increase in PVP/C60 concentration. While pure PVP is homogeneously distributed between the gel and the surrounding solution, a slight concentration of complexes outside the gel was recorded. It was attributed to PVP/C60 hydrophobicity leading to the decrease in the thermodynamic quality of fullerene-containing solution being gel solvent. The release of PVP/C60 solutions induced by shear was studied with counter-rotating rheo-optical technique and compared with PVP solution release under the same conditions. The amount of solution released depends on polymer concentration and shear strain. Contrary to pure PVP solutions in which rate of release decreases with the increase in polymer concentration, PVP/C60 complexes are released faster when fullerene concentration inside the gel is higher.

Aging increases amyloid beta-peptide-induced 8-iso-prostaglandin F2alpha release from rat brain.

PubMed

Brunetti, Luigi; Michelotto, Barbara; Orlando, Giustino; Recinella, Lucia; Di Nisio, Chiara; Ciabattoni, Giovanni; Vacca, Michele

2004-01-01

In order to investigate whether amyloid beta-peptide-induced oxidative damage in the brain could be related to aging, we studied the release of 8-iso-prostaglandin (PG)F2alpha, a stable marker of cellular oxidative stress, in brain synaptosomes from Wistar rats of different ages (3, 6, 12, 18 months old), both basally and after amyloid beta-peptide (1-40) perfusion. We found that basal release of 8-iso-PGF2alpha was not significantly different among all age groups of rats. Either phospholipase A2 activation induced by calcium ionophore A23187 (10 nM) or amyloid beta-peptide (5 microM) did not modify isoprostane release, when these substances were used alone. In contrast, amyloid beta-peptide (1-5 microM) preincubation caused a dose-dependent increase of A23187-stimulated 8-iso-PGF2alpha release in each age group, which was also strikingly correlated to aging of rats. Furthermore, ferric ammonium sulfate stimulates isoprostane production to levels comparable to those induced by amyloid beta-peptide. In conclusion, although 8-iso-PGF2alpha production from rat brain synaptosomes is independent from aging in the basal state, aging renders neurons more vulnerable to amyloid beta-peptide-induced oxidative toxicity.

N-Acetylcysteine Amide Protects Against Oxidative Stress–Induced Microparticle Release From Human Retinal Pigment Epithelial Cells

PubMed Central

Carver, Kyle A.; Yang, Dongli

2016-01-01

Purpose Oxidative stress is a major factor involved in retinal pigment epithelium (RPE) apoptosis that underlies AMD. Drusen, extracellular lipid- and protein-containing deposits, are strongly associated with the development of AMD. Cell-derived microparticles (MPs) are small membrane-bound vesicles shed from cells. The purpose of this study was to determine if oxidative stress drives MP release from RPE cells, to assess whether these MPs carry membrane complement regulatory proteins (mCRPs: CD46, CD55, and CD59), and to evaluate the effects of a thiol antioxidant on oxidative stress–induced MP release. Methods Retinal pigment epithelium cells isolated from human donor eyes were cultured and treated with hydrogen peroxide (H2O2) to induce oxidative stress. Isolated MPs were fixed for transmission electron microscopy or processed for component analysis by flow cytometry, Western blot analysis, and confocal microscopy. Results Transmission electron microscopy showed that MPs ranged in diameter from 100 to 1000 nm. H2O2 treatment led to time- and dose-dependent elevations in MPs with externalized phosphatidylserine and phosphatidylethanolamine, known markers of MPs. These increases were strongly correlated to RPE apoptosis. Oxidative stress significantly increased the release of mCRP-positive MPs, which were prevented by a thiol antioxidant, N-acetylcysteine amide (NACA). Conclusions This is the first evidence that oxidative stress induces cultured human RPE cells to release MPs that carry mCRPs on their surface. The levels of released MPs are strongly correlated with RPE apoptosis. N-acetylcysteine amide prevents oxidative stress–induced effects. Our findings indicate that oxidative stress reduces mCRPs on the RPE surface through releasing MPs. PMID:26842754

Vinpocetine inhibits glutamate release induced by the convulsive agent 4-aminopyridine more potently than several antiepileptic drugs.

PubMed

Sitges, M; Sanchez-Tafolla, B M; Chiu, L M; Aldana, B I; Guarneros, A

2011-10-01

4-Aminopyridine (4-AP) is a convulsing agent that in vivo preferentially releases Glu, the most important excitatory amino acid neurotransmitter in the brain. Here the ionic dependence of 4-AP-induced Glu release and the effects of several of the most common antiepileptic drugs (AEDs) and of the new potential AED, vinpocetine on 4-AP-induced Glu release were characterized in hippocampus isolated nerve endings pre-loaded with labelled Glu ([3H]Glu). 4-AP-induced [3H]Glu release was composed by a tetrodotoxin (TTX) sensitive and external Ca2+ dependent fraction and a TTX insensitive fraction that was sensitive to the excitatory amino acid transporter inhibitor, TBOA. The AEDs: carbamazepine, phenytoin, lamotrigine and oxcarbazepine at the highest dose tested only reduced [3H]Glu release to 4-AP between 50-60%, and topiramate was ineffective. Vinpocetine at a much lower concentration than the above AEDs, abolished [3H]Glu release to 4-AP. We conclude that the decrease in [3H]Glu release linked to the direct blockade of presynaptic Na+ channels, may importantly contribute to the anticonvulsant actions of all the drugs tested here (except topiramate); and that the significantly greater vinpocetine effect in magnitude and potency on [3H]Glu release when excitability is exacerbated like during seizures, may involve the increase additionally exerted by vinpocetine in some K+ channels permeability. Copyright © 2011 Elsevier B.V. All rights reserved.

Exhaustive Exercise-induced Oxidative Stress Alteration of Erythrocyte Oxygen Release Capacity.

PubMed

Xiong, Yanlian; Xiong, Yanlei; Wang, Yueming; Zhao, Yajin; Li, Yaojin; Ren, Yang; Wang, Ruofeng; Zhao, Mingzi; Hao, Yitong; Liu, Haibei; Wang, Xiang

2018-05-24

The aim of the present study is to explore the effect of exhaustive running exercise (ERE) in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control (C), moderate running exercise (MRE) and exhaustive running exercise groups. The thermodynamics and kinetics properties of the erythrocyte oxygen release process of different groups were tested. We also determined the degree of band-3 oxidative and phosphorylation, anion transport activity and carbonic anhydrase isoform II(CAII) activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in TBARS and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II(CAII) activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamics and kinetics properties of RBCs oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive running induced alterations in erythrocytes oxygen release thermodynamics and kinetics properties.

Mitochondrial Reactive Oxygen Species (ROS) and ROS-Induced ROS Release

PubMed Central

Zorov, Dmitry B.; Juhaszova, Magdalena; Sollott, Steven J.

2014-01-01

Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca2+, etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca2+). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo. PMID:24987008

Polysaccharide peptides from COV-1 strain of Coriolus versicolor induce hyperalgesia via inflammatory mediator release in the mouse.

PubMed

Chan, Siu-Lung; Yeung, John H K

2006-04-18

Polysaccharide peptide (PSP), isolated from Coriolus versicolor COV-1, has been widely used as an adjunct to cancer chemotherapy and as an immuno-stimulator in China. In this study, the anti-nociceptive effects of PSP were investigated in two different pain models in the mouse. In the acetic acid-induced writhing model, initial studies showed that PSP decreased the number of acetic acid-induced writhing by 92.9%, which, by definition, would constitute an analgesic effect. However, further studies showed that PSP itself induced a dose-dependent writhing response. Studies on inflammatory mediator release showed that PSP increased the release of prostaglandin E2, tumor necrosis factor-alpha, interleukin-1beta, and histamine in mouse peritoneal macrophages and mast cells both in vitro and in vivo. The role of inflammatory mediator release in PSP-induced writhing was confirmed when diclofenac and dexamethasone decreased the number of writhing responses by 54% and 58.5%, respectively. Diphenhydramine totally inhibited the PSP-induced writhing. In the hot-plate test, PSP dose-dependently shortened the hind paw withdrawal latency, indicative of a hyperalgesic effect. The hyperalgesic effect was reduced by pretreatment with the anti-inflammatory drugs. In conclusion, the PSP-induced hyperalgesia was related to activation of peritoneal resident cells and an increase in the release of inflammatory mediators.

Mitochondria released by cells undergoing TNF-α-induced necroptosis act as danger signals.

PubMed

Maeda, A; Fadeel, B

2014-07-03

Necrosis leads to the release of so-called damage-associated molecular patterns (DAMPs), which may provoke inflammatory responses. However, the release of organelles from dying cells, and the consequences thereof have not been documented before. We demonstrate here that mitochondria are released from cells undergoing tumor necrosis factor-α (TNF-α)-induced, receptor-interacting protein (RIP)1-dependent necroptosis, a form of programmed necrosis. The released, purified mitochondria were determined to be intact as they did not emit appreciable amounts of mitochondrial DNA (mtDNA). Pharmacological inhibition of dynamin-related protein 1 (Drp1) prevented mitochondrial fission in TNF-α-triggered cells, but this did not block necroptosis nor the concomitant release of mitochondria. Importantly, primary human macrophages and dendritic cells engulfed mitochondria from necroptotic cells leading to modulation of macrophage secretion of cytokines and induction of dendritic cell maturation. Our results show that intact mitochondria are released from necroptotic cells and suggest that these organelles act as bona fide danger signals.

Hypoxia-induced angiogenesis is increased by the controlled release of deferoxiamine from gelatin hydrogels.

PubMed

Saito, Takashi; Tabata, Yasuhiko

2014-08-01

The objective of this study is to design biodegradable hydrogels for the controlled release of deferoxiamine (DFO) and evaluate their biological activity. When the DFO was added to human umbilical vein endothelial cells cultured in 5.0% O2, the level of hypoxia-inducible factor-1α and vascular endothelial growth factor significantly increased compared with that without DFO. The expression of angiogenesis-related genes was accordingly increased by the DFO addition. An aqueous solution of mixed gelatin and DFO was freeze-dried, and dehydrothermally treated at 140°C for 24h to prepare a gelatin hydrogel incorporating DFO. In the release test with phosphate-buffered saline solution (PBS) at 37°C, an initial DFO release of 60% was observed, followed by no release. When placed in PBS containing collagenase, the hydrogel was enzymatically degraded with time, and consequently released DFO in a degradation-dependent manner. After the hydrogel incorporating DFO was injected intramuscularly into a mouse model of hind limb ischemia, the number of new blood vessels formed was significantly higher than that with free DFO and DFO-free hydrogel. It is concluded that the DFO-containing hydrogel shows promising for inducing angiogenesis locally. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Enhanced basophil histamine release and neutrophil chemotactic activity predispose grain dust-induced airway obstruction.

PubMed

Park, H; Jung, K; Kang, K; Nahm, D; Cho, S; Kim, Y

1999-04-01

The pathogenic mechanism of grain dust (GD)-induced occupational asthma (OA) remains unclear. To understand further the mechanism of GD-induced OA. Fifteen employees working in a same GD industry, complaining of work-related respiratory symptoms, were enrolled and were divided into two groups according to the GD-bronchoprovocation test (BPT) result: six positive responders were grouped as group III, nine negative responders as group II and five healthy controls as group I. Serum GD-specific immunoglobulin (Ig)E (sIgE), specific IgG (sIgG) and specific IgG4 (sIgG4) antibodies were detected by enzyme-linked immunosorbent assay. Basophil histamine release was measured by the autofluorometric method, and changes of serum neutrophil chemotactic activity were observed by the Boyden chamber method. For clinical parameters such as degree of airway hyperresponsiveness to methacholine, duration of respiratory symptoms, exposure duration, and prevalences of serum sIgE, sIgG and sIgG4 antibodies, there were no significant differences between group II and III (P > 0.05, respectively). Serum neutrophil chemotactic activity increased significantly at 30 min and decreased at 240 min after the GD-BPT in group III subjects (P < 0.05, respectively), while no significant changes were noted in group II subjects (P > 0.05). Basophil histamine release induced by GD was significantly higher in group III than those of group I or group II (P < 0.05, respectively), while minimal release of anti-IgG4 antibodies was noted in all three groups. These results suggest that enhanced basophil histamine release and serum neutrophil chemotactic activity might contribute to the development of GD-induced occupational asthma.

Midazolam suppresses interleukin-1β-induced interleukin-6 release from rat glial cells

PubMed Central

2011-01-01

Background Peripheral-type benzodiazepine receptor (PBR) expression levels are low in normal human brain, but their levels increase in inflammation, brain injury, neurodegenerative states and gliomas. It has been reported that PBR functions as an immunomodulator. The mechanisms of action of midazolam, a benzodiazepine, in the immune system in the CNS remain to be fully elucidated. We previously reported that interleukin (IL)-1β stimulates IL-6 synthesis from rat C6 glioma cells and that IL-1β induces phosphorylation of inhibitory kappa B (IκB), p38 mitogen-activated protein (MAP) kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2, and signal transducer and activator of transcription (STAT)3. It has been shown that p38 MAP kinase is involved in IL-1β-induced IL-6 release from these cells. In the present study, we investigated the effect of midazolam on IL-1β-induced IL-6 release from C6 cells, and the mechanisms of this effect. Methods Cultured C6 cells were stimulated by IL-1β. IL-6 release from C6 cells was measured using an enzyme-linked immunosorbent assay, and phosphorylation of IκB, the MAP kinase superfamily, and STAT3 was analyzed by Western blotting. Results Midazolam, but not propofol, inhibited IL-1β-stimulated IL-6 release from C6 cells. The IL-1β-stimulated levels of IL-6 were suppressed by wedelolactone (an inhibitor of IκB kinase), SP600125 (an inhibitor of SAPK/JNK), and JAK inhibitor I (an inhibitor of JAK 1, 2 and 3). However, IL-6 levels were not affected by PD98059 (an inhibitor of MEK1/2). Midazolam markedly suppressed IL-1β-stimulated STAT3 phosphorylation without affecting the phosphorylation of p38 MAP kinase, SAPK/JNK or IκB. Conclusion These results strongly suggest that midazolam inhibits IL-1β-induced IL-6 release in rat C6 glioma cells via suppression of STAT3 activation. Midazolam may affect immune system function in the CNS. PMID:21682888

Rotenone and Paraquat do not Directly Activate Microglia or Induce Inflammatory Cytokine Release

PubMed Central

Klintworth, Heather; Garden, Gwenn; Xia, Zhengui

2009-01-01

Both epidemiological and pathological data suggest an inflammatory response including microglia activation and neuro-inflammation in the Parkinsonian brain. Treatments with lipopolysacchride (LPS), rotenone and paraquat have been used as models for Parkinson’s disease, as they cause dopaminergic neuron degeneration in culture and in animals. Recent studies have suggested that rotenone and paraquat induce neuro-inflammation, however, it is not known if they can directly activate microglia. Here, we use primary cultured microglia to address this question. Microglia activation was analyzed by morphological changes and release of nitric oxide and inflammatory cytokines. Treatment with LPS was used as a positive control. While LPS induced morphological changes characteristic of microglial activation and release of nitric oxide and inflammatory cytokines, rotenone and paraquat did not. Our results suggest that paraquat and rotenone do not act directly on microglia and that neuro-inflammation and microglial activation in animals treated with these agents is likely non-cell autonomous, and may occur as a result of dopaminergic neuron damage or factors released by neurons and other cells. PMID:19559752

Experimental investigation of cavitation induced air release

NASA Astrophysics Data System (ADS)

Kowalski, Karoline; Pollak, Stefan; Hussong, Jeanette

Variations in cross-sectional areas may lead to pressure drops below a critical value, such that cavitation and air release are provoked in hydraulic systems. Due to a relatively slow dissolution of gas bubbles, the performance of hydraulic systems will be affected on long time scales by the gas phase. Therefore predictions of air production rates are desirable to describe the system characteristics. Existing investigations on generic geometries such as micro-orifice flows show an outgassing process due to hydrodynamic cavitation which takes place on time scales far shorter than diffusion processes. The aim of the present investigation is to find a correlation between global, hydrodynamic flow characteristics and cavitation induced undissolved gas fractions generated behind generic flow constrictions such as an orifice or venturi tube. Experimental investigations are realised in a cavitation channel that enables an independent adjustment of the pressure level upstream and downstream of the orifice. Released air fractions are determined by means of shadowgraphy imaging. First results indicate that an increased cavitation activity leads to a rapid increase in undissolved gas volume only in the choking regime. The frequency distribution of generated gas bubble size seems to depend only indirectly on the cavitation intensity driven by an increase of downstream coalescence events due to a more densely populated bubbly flow.

Fractalkine is a "find-me" signal released by neurons undergoing ethanol-induced apoptosis.

PubMed

Sokolowski, Jennifer D; Chabanon-Hicks, Chloe N; Han, Claudia Z; Heffron, Daniel S; Mandell, James W

2014-01-01

Apoptotic neurons generated during normal brain development or secondary to pathologic insults are efficiently cleared from the central nervous system. Several soluble factors, including nucleotides, cytokines, and chemokines are released from injured neurons, signaling microglia to find and clear debris. One such chemokine that serves as a neuronal-microglial communication factor is fractalkine, with roles demonstrated in several models of adult neurological disorders. Lacking, however, are studies investigating roles for fractalkine in perinatal brain injury, an important clinical problem with no effective therapies. We used a well-characterized mouse model of ethanol-induced apoptosis to assess the role of fractalkine in neuronal-microglial signaling. Quantification of apoptotic debris in fractalkine-knockout (KO) and CX3CR1-KO mice following ethanol treatment revealed increased apoptotic bodies compared to wild type mice. Ethanol-induced injury led to release of soluble, extracellular fractalkine. The extracellular media harvested from apoptotic brains induces microglial migration in a fractalkine-dependent manner that is prevented by neutralization of fractalkine with a blocking antibody or by deficiency in the receptor, CX3CR1. This suggests fractalkine acts as a "find-me" signal, recruiting microglial processes toward apoptotic cells to promote their clearance. Next, we aimed to determine whether there are downstream alterations in cytokine gene expression due to fractalkine signaling. We examined mRNA expression in fractalkine-KO and CX3CR1-KO mice after alcohol-induced apoptosis and found differences in cytokine production in the brains of these KOs by 6 h after ethanol treatment. Collectively, this suggests that fractalkine acts as a "find me" signal released by apoptotic neurons, and subsequently plays a critical role in modulating both clearance and inflammatory cytokine gene expression after ethanol-induced apoptosis.

Intermittent hydrostatic pressure inhibits shear stress-induced nitric oxide release in human osteoarthritic chondrocytes in vitro.

PubMed

Lee, Mel S; Trindade, Michael C D; Ikenoue, Takashi; Schurman, David J; Goodman, Stuart B; Smith, R Lane

2003-02-01

To test the effects of intermittent hydrostatic pressure (IHP) on nitric oxide (NO) release induced by shear stress and matrix macromolecule gene expression in human osteoarthritic chondrocytes in vitro. Chondrocytes isolated from cartilage samples from 9 patients with osteoarthritis were cultured and exposed to either shear stress or an NO donor. Nitrite concentration was measured using the Griess reaction. Matrix macromolecule mRNA signal levels were determined using reverse-transcriptase polymerase chain reaction and quantified by imaging analysis software. Exposure to shear stress upregulated NO release in a dose and time-dependent manner. Application of IHP inhibited shear stress induced NO release but did not alter NO release from chondrocytes not exposed to shear stress. Shear stress induced NO or addition of an NO donor (sodium nitroprusside) was associated with decreased mRNA signal levels for the cartilage matrix proteins, aggrecan, and type II collagen. Intermittent hydrostatic pressure blocked the inhibitory effects of sodium nitroprusside but did not alter the inhibitory effects of shear stress on cartilage macromolecule gene expression. Our data show that shear stress and IHP differentially alter chondrocyte metabolism and suggest that a balance of effects between different loading forces preserve cartilage extracellular matrix in vivo.

Noradrenaline induces peripheral antinociception by endogenous opioid release.

PubMed

Romero, Thiago Roberto Lima; Soares Santos, Raquel Rodrigues; Castor, Marina Gomes Miranda E; Petrocchi, Júlia Alvarenga; Guzzo, Luciana Souza; Klein, Andre; Duarte, Igor Dimitri Gama

2018-02-23

The aim of this study was to investigate this involvement in not inflammatory model of pain and which opioid receptor subtype mediates noradrenaline-induced peripheral antinociception. NA is involved in the intrinsic control of pain-inducing pro-nociceptive effects in the primary afferent nociceptors. However, inflammation can induce various plastic changes in the central and peripheral noradrenergic system that, upon interaction with the immune system, may contribute, in part, to peripheral antinociception. Hyperalgesia was induced by intraplantar injection of prostaglandin E 2 (PGE 2 , 2 μg) into the plantar surface of the right hind paw and the paw pressure test to evaluated the hyperalgesia was used. Noradrenaline (NA) was administered locally into right hind paw of Wistar rat (160-200 g) alone and after either agents, α 2 -adrenoceptor antagonist yohimbine, α 1 -adrenoceptor antagonist prazosin, β-adrenoceptor antagonist propranolol, μ-opioid antagonist clocinnamox, δ-opioid antagonist naltrindole and κ-opioid antagonist nor-binaltorfimina. In addition, the enkephalinase inhibitor bestatin was administered prior to NA low dose. Intraplantar injection of NA induced peripheral antinociception against hyperalgesia induced by PGE 2 . This effect was reversed, in dose dependent manner, by intraplantar injection of yohimbine, prazosin, propranolol, clocinnamox and naltrindole. However, injection of nor-binaltorfimina did not alter antinociception of NA after PGE 2 hyperalgesia. Bestatin intensified the antinociceptive effects of low-dose of NA. Besides the α 2 -adrenoceptor, the present data provide evidence that, in absence of inflammation, NA activating α 1 and β-adrenoceptor induce endogenous opioid release to produce peripheral antinociceptive effect by μ and δ opioid receptors. Copyright © 2018 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Suckling induced insulin-like growth factor-1 (IGF-1) release in mother rats.

PubMed

Lékó, András H; Cservenák, Melinda; Dobolyi, Árpád

2017-12-01

Lactation involves significant neuroendocrine changes. The elevated prolactin (PRL) release from the pituitary, induced markedly by suckling, is the most relevant example. Suckling also causes a significant and rapid elevation in growth hormone (GH) levels. GH is necessary for milk synthesis as milk yield is stopped completely in the absence of PRL and GH, while the absence of PRL alone causes only a 50% reduction. Insulin-like growth factor-1 (IGF-1) plays an important role in the GH axis. GH exerts its effects through IGF-1 in the periphery, for example in the mammary gland. In addition, IGF-1 is responsible for the long-loop feedback control of GH secretion. IGF-1 secretion has not been established yet in mothers. Therefore, in the present study, we investigated the effect of suckling on serum IGF-1 level in rat mothers and correlated it with serum PRL levels. We examined a potential mechanism of the regulation of IGF-1 level during suckling by administering IGF-1 into the lateral ventricle of rat mothers continuously for 12days, or acutely, right before the start of suckling. We described that suckling affected IGF-1 release based on one-way repeated measures ANOVA (F=10.8 and p<0.001) and caused a marked increase of IGF-1 level 30min after the start of suckling (p<0.001). We demonstrated a significant (p<0.05; the correlation coefficient was 0.29) correlation to PRL level during suckling which supports that PRL could induce IGF-1 release. The prolonged central IGF-1 administration diminished the suckling-induced IGF-1 surge (F=9.19 and p<0.001) while the acute treatment did not have any effect compared to artificial cerebrospinal fluid injection, analysed with two-way repeated measures ANOVA. In conclusion, suckling induces IGF-1 release either by elevating PRL or GH. Long-loop feedback via IGF-1 in the GH axis can diminish this action. Copyright © 2017 Elsevier Ltd. All rights reserved.

Formononetin inhibits lipopolysaccharide-induced release of high mobility group box 1 by upregulating SIRT1 in a PPARδ-dependent manner.

PubMed

Hwang, Jung Seok; Kang, Eun Sil; Han, Sung Gu; Lim, Dae-Seog; Paek, Kyung Shin; Lee, Chi-Ho; Seo, Han Geuk

2018-01-01

The release of high mobility group box 1 (HMGB1) induced by inflammatory signals acts as a cellular alarmin to trigger a chain of inflammatory responses. Although the inflammatory actions of HMGB1 are well studied, less is known about the therapeutic agents that can impede its release. This study investigated whether the isoflavonoid formononetin can modulate HMGB1 release in cellular inflammatory responses. RAW264.7 murine macrophages were exposed to lipopolysaccharide (LPS) in the presence or absence of formononetin. The levels of HMGB1 release, sirtuin 1 (SIRT1) expression, and HMGB1 acetylation were analyzed by immunoblotting and real-time polymerase chain reaction. The effects of resveratrol and sirtinol, an activator and inhibitor of SIRT1, respectively, on LPS-induced HMGB1 release were also evaluated. Formononetin modulated cellular inflammatory responses by suppressing the release of HMGB1 by macrophages exposed to LPS. In RAW264.7 cells, formononetin significantly attenuated LPS-induced release of HMGB1 into the extracellular environment, which was accompanied by a reduction in its translocation from the nucleus to the cytoplasm. In addition, formononetin significantly induced mRNA and protein expression of SIRT1 in a peroxisome proliferator-activated receptor δ (PPARδ)-dependent manner. These effects of formononetin were dramatically attenuated in cells treated with small interfering RNA (siRNA) against PPARδ or with GSK0660, a specific inhibitor of PPARδ, indicating that PPARδ is involved in formononetin-mediated SIRT1 expression. In line with these effects, formononetin-mediated inhibition of HMGB1 release in LPS-treated cells was reversed by treatment with SIRT1-targeting siRNA or sirtinol, a SIRT1 inhibitor. By contrast, resveratrol, a SIRT1 activator, further potentiated the inhibitory effect of formononetin on LPS-induced HMGB1 release, revealing a possible mechanism by which formononetin regulates HMGB1 release through SIRT1. Furthermore

Formononetin inhibits lipopolysaccharide-induced release of high mobility group box 1 by upregulating SIRT1 in a PPARδ-dependent manner

PubMed Central

Hwang, Jung Seok; Kang, Eun Sil; Han, Sung Gu; Lim, Dae-Seog; Paek, Kyung Shin; Lee, Chi-Ho

2018-01-01

Background The release of high mobility group box 1 (HMGB1) induced by inflammatory signals acts as a cellular alarmin to trigger a chain of inflammatory responses. Although the inflammatory actions of HMGB1 are well studied, less is known about the therapeutic agents that can impede its release. This study investigated whether the isoflavonoid formononetin can modulate HMGB1 release in cellular inflammatory responses. Methods RAW264.7 murine macrophages were exposed to lipopolysaccharide (LPS) in the presence or absence of formononetin. The levels of HMGB1 release, sirtuin 1 (SIRT1) expression, and HMGB1 acetylation were analyzed by immunoblotting and real-time polymerase chain reaction. The effects of resveratrol and sirtinol, an activator and inhibitor of SIRT1, respectively, on LPS-induced HMGB1 release were also evaluated. Results Formononetin modulated cellular inflammatory responses by suppressing the release of HMGB1 by macrophages exposed to LPS. In RAW264.7 cells, formononetin significantly attenuated LPS-induced release of HMGB1 into the extracellular environment, which was accompanied by a reduction in its translocation from the nucleus to the cytoplasm. In addition, formononetin significantly induced mRNA and protein expression of SIRT1 in a peroxisome proliferator-activated receptor δ (PPARδ)-dependent manner. These effects of formononetin were dramatically attenuated in cells treated with small interfering RNA (siRNA) against PPARδ or with GSK0660, a specific inhibitor of PPARδ, indicating that PPARδ is involved in formononetin-mediated SIRT1 expression. In line with these effects, formononetin-mediated inhibition of HMGB1 release in LPS-treated cells was reversed by treatment with SIRT1-targeting siRNA or sirtinol, a SIRT1 inhibitor. By contrast, resveratrol, a SIRT1 activator, further potentiated the inhibitory effect of formononetin on LPS-induced HMGB1 release, revealing a possible mechanism by which formononetin regulates HMGB1 release

Mechanical stretch induces MMP-2 release and activation in lung endothelium: role of EMMPRIN.

PubMed

Haseneen, Nadia A; Vaday, Gayle G; Zucker, Stanley; Foda, Hussein D

2003-03-01

High-volume mechanical ventilation leads to ventilator-induced lung injury. This type of lung injury is accompanied by an increased release and activation of matrix metalloproteinases (MMPs). To investigate the mechanism leading to the increased MMP release, we systematically studied the effect of mechanical stretch on human microvascular endothelial cells isolated from the lung. We exposed cells grown on collagen 1 BioFlex plates to sinusoidal cyclic stretch at 0.5 Hz using the Flexercell system with 17-18% elongation of cells. After 4 days of cell stretching, conditioned media and cell lysate were collected and analyzed by gelatin, casein, and reverse zymograms as well as Western blotting. RT-PCR of mRNA extracted from stretched cells was performed. Our results show that 1) cyclic stretch led to increased release and activation of MMP-2 and MMP-1; 2) the activation of MMP-2 was accompanied by an increase in membrane type-1 MMP (MT1-MMP) and inhibited by a hydroxamic acid-derived inhibitor of MMPs (Prinomastat, AG3340); and 3) the MMP-2 release and activation were preceded by an increase in production of extracellular MMP inducer (EMMPRIN). These results suggest that cyclic mechanical stretch leads to MMP-2 activation through an MT1-MMP mechanism. EMMPRIN may play an important role in the release and activation of MMPs during lung injury.

Anaplerotic input is sufficient to induce time-dependent potentiation of insulin release in rat pancreatic islets.

PubMed

Gunawardana, Subhadra C; Liu, Yi-Jia; Macdonald, Michael J; Straub, Susanne G; Sharp, Geoffrey W G

2004-11-01

Nutrients that induce biphasic insulin release, such as glucose and leucine, provide acetyl-CoA and anaplerotic input in the beta-cell. The first phase of release requires increased ATP production leading to increased intracellular Ca(2+) concentration ([Ca(2+)](i)). The second phase requires increased [Ca(2+)](i) and anaplerosis. There is strong evidence to indicate that the second phase is due to augmentation of Ca(2+)-stimulated release via the K(ATP) channel-independent pathway. To test whether the phenomenon of time-dependent potentiation (TDP) has similar properties to the ATP-sensitive K(+) channel-independent pathway, we monitored the ability of different agents that provide acetyl-CoA and anaplerotic input or both of these inputs to induce TDP. The results show that anaplerotic input is sufficient to induce TDP. Interestingly, among the agents tested, the nonsecretagogue glutamine, the nonhydrolyzable analog of leucine aminobicyclo[2.2.1]heptane-2-carboxylic acid, and succinic acid methyl ester all induced TDP, and all significantly increased alpha-ketoglutarate levels in the islets. In conclusion, anaplerosis that enhances the supply and utilization of alpha-ketoglutarate in the tricarboxylic acid cycle appears to play an essential role in the generation of TDP.

Effective Anti-miRNA Oligonucleotides Show High Releasing Rate of MicroRNA from RNA-Induced Silencing Complex.

PubMed

Ariyoshi, Jumpei; Matsuyama, Yohei; Kobori, Akio; Murakami, Akira; Sugiyama, Hiroshi; Yamayoshi, Asako

2017-10-01

MicroRNAs (miRNAs) regulate gene expression by forming RNA-induced silencing complexes (RISCs) and have been considered as promising therapeutic targets. MiRNA is an essential component of RISC for the modulation of gene expression. Therefore, the release of miRNA from RISC is considered as an effective method for the inhibition of miRNA functions. In our previous study, we reported that anti-miRNA oligonucleotides (AMOs), which are composed of the 2'-O-methyl (2'-OMe) RNA, could induce the release of miRNA from RISC. However, the mechanisms underlying the miRNA-releasing effects of chemically modified AMOs, which are conventionally used as anti-cancer drugs, are still unclear. In this study, we investigated the relationship between the miRNA releasing rate from RISC and the inhibitory effect on RISC activity (IC 50 ) using conventional chemically modified AMOs. We demonstrated that the miRNA-releasing effects of AMOs are directly proportional to the IC 50 values, and AMOs, which have an ability to promote the release of miRNA from RISC, can effectively inhibit RISC activity in living cells.

Concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots. [Medicago sativa L. ; Rhizobium meliloti

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, C.A.; Phillips, D.A.

Flavonoid signals from alfalfa (Medicago sativa L.) induce transcription of nodulation (nod) genes in Rhizobium meliloti. Alfalfa roots release three major nod-gene inducers: 4{prime},7-dihydroxyflavanone, 4{prime},7-dihydroxyflavone, and 4,4{prime}-dihydroxy-2{prime}-methoxychalcone. The objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. Requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings with (U-{sup 14}C)-L-phenylalanine in the presence or absence of the phenylalanine ammonia-lyase inhibitor L-2-aminoxy-3-phenylpropionic acid (AOPP). In the absence of AOPP, each of the three flavonoids in exudates contained {sup 14}C. In the presence of AOPP, {sup 14}C labeling and releasemore » of all the exuded nod-gene inducers were reduced significantly. AOPP inhibited labeling and release of the strongest nod-gene inducer, methoxychalcone, by more than 90%. The release process responsible for exudation of nod-gene inducers appears to be specific rather than a general phenomenon such as a sloughing off of cells during root growth.« less

Tyramine-induced noradrenaline release from rat brain slices: prevention by (-)-deprenyl.

PubMed Central

Glover, V.; Pycock, C. J.; Sandler, M.

1983-01-01

Clorgyline (1 and 10 microM) and (+)-deprenyl (10 microM) both significantly potentiated the tyramine (100 microM)-induced release of [3H]-noradrenaline from rat cerebral cortex slices. (-)-Deprenyl (50 microM) significantly reduced it, while lower concentrations had no effect on noradrenaline release. However, in combination, 1 microM (-)-deprenyl blocked the release-facilitating action of 1 microM clorgyline, and 10 microM (-)-deprenyl that of 10 microM (+)-deprenyl. Low concentrations of (+)- and (-)-deprenyl (1 and 10 microM), both selectively inhibited phenylethylamine oxidation by monoamine oxidase B. Higher concentrations of (-)-deprenyl (20 and 50 microM) also inhibited 5-hydroxytryptamine oxidation by monoamine oxidase A. Clorgyline (1 and 10 microM) inhibited both enzymes. Thus, the effects of these drugs on noradrenaline-release cannot be explained solely in terms of irreversible inhibition of monoamine oxidase A and B, and other possible mechanisms are discussed. If the brain-slice model faithfully mirrors the sequence of events manifesting peripherally as the tyramine hypertensive response ('cheese effect'), then it is possible that low doses of (-)-deprenyl, administered with antidepressant monoamine oxidase inhibitors, can prevent this adverse reaction. PMID:6418254

Preprotein transport machineries of yeast mitochondrial outer membrane are not required for Bax-induced release of intermembrane space proteins.

PubMed

Sanjuán Szklarz, Luiza K; Kozjak-Pavlovic, Vera; Vögtle, F-Nora; Chacinska, Agnieszka; Milenkovic, Dusanka; Vogel, Sandra; Dürr, Mark; Westermann, Benedikt; Guiard, Bernard; Martinou, Jean-Claude; Borner, Christoph; Pfanner, Nikolaus; Meisinger, Chris

2007-04-20

The mitochondrial outer membrane contains protein import machineries, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It has been speculated that TOM or SAM are required for Bax-induced release of intermembrane space (IMS) proteins; however, experimental evidence has been scarce. We used isolated yeast mitochondria as a model system and report that Bax promoted an efficient release of soluble IMS proteins while preproteins were still imported, excluding an unspecific damage of mitochondria. Removal of import receptors by protease treatment did not inhibit the release of IMS proteins by Bax. Yeast mutants of each Tom receptor and the Tom40 channel were not impaired in Bax-induced protein release. We analyzed a large collection of mutants of mitochondrial outer membrane proteins, including SAM, fusion and fission components, but none of these components was required for Bax-induced protein release. The released proteins included complexes up to a size of 230 kDa. We conclude that Bax promotes efficient release of IMS proteins through the outer membrane of yeast mitochondria while the inner membrane remains intact. Inactivation of the known protein import and sorting machineries of the outer membrane does not impair the function of Bax at the mitochondria.

Cysteine analogues potentiate glucose-induced insulin release in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ammon, H.P.; Hehl, K.H.; Enz, G.

1986-12-01

In rat pancreatic islets, cysteine analogues, including glutathione, acetylcysteine, cysteamine, D-penicillamine, L-cysteine ethyl ester, and cysteine-potentiated glucose (11.1 mM) induced insulin secretion in a concentration-dependent manner. Their maximal effects were similar and occurred at approximately 0.05, 0.05, 0.1, 0.5, 1.0, 1.0 mM, respectively. At substimulatory glucose levels (2.8 mM), insulin release was not affected by these compounds. In contrast, thiol compounds, structurally different from cysteine and its analogues, such as mesna, tiopronin, meso-2,3-dimercaptosuccinic acid (DMSA), dimercaprol (BAL), beta-thio-D-glucose, as well as those cysteine analogues that lack a free-thiol group, including L-cystine, cystamine, D-penicillamine disulfide, S-carbocysteine, and S-carbamoyl-L-cysteine, did not enhancemore » insulin release at stimulatory glucose levels (11.1 mM); cystine (5 mM) was inhibitory. These in vitro data indicate that among the thiols tested here, only cysteine and its analogues potentiate glucose-induced insulin secretion, whereas thiols that are structurally not related to cysteine do not. This suggests that a cysteine moiety in the molecule is necessary for the insulinotropic effect. For their synergistic action to glucose, the availability of a sulfhydryl group is also a prerequisite. The maximal synergistic action is similar for all cysteine analogues tested, whereas the potency of action is different, suggesting similarity in the mechanism of action but differences in the affinity to the secretory system.« less

Endogenously Released Neuropeptide Y Suppresses Hippocampal Short-Term Facilitation and Is Impaired by Stress-Induced Anxiety

PubMed Central

Li, Qin; Bartley, Aundrea F.

2017-01-01

Neuropeptide Y (NPY) has robust anxiolytic properties and is reduced in patients with anxiety disorders. However, the mechanisms by which NPY modulates circuit function to reduce anxiety behavior are not known. Anxiolytic effects of NPY are mediated in the CA1 region of hippocampus, and NPY injection into hippocampus alleviates anxiety symptoms in the predator scent stress model of stress-induced anxiety. The mechanisms that regulate NPY release, and its effects on CA1 synaptic function, are not fully understood. Here we show in acute hippocampal slices from mice that endogenous NPY, released in response to optogenetic stimulation or synaptically evoked spiking of NPY+ cells, suppresses both of the feedforward pathways to CA1. Stimulation of temporoammonic synapses with a physiologically derived spike train causes NPY release that reduces short-term facilitation, whereas the release of NPY that modulates Schaffer collateral synapses requires integration of both the Schaffer collateral and temporoammonic pathways. Pathway specificity of NPY release is conferred by three functionally distinct NPY+ cell types, with differences in intrinsic excitability and short-term plasticity of their inputs. Predator scent stress abolishes the release of endogenous NPY onto temporoammonic synapses, a stress-sensitive pathway, thereby causing enhanced short-term facilitation. Our results demonstrate how stress alters CA1 circuit function through the impairment of endogenous NPY release, potentially contributing to heightened anxiety. SIGNIFICANCE STATEMENT Neuropeptide Y (NPY) has robust anxiolytic properties, and its levels are reduced in patients with post-traumatic stress disorder. The effects of endogenously released NPY during physiologically relevant stimulation, and the impact of stress-induced reductions in NPY on circuit function, are unknown. By demonstrating that NPY release modulates hippocampal synaptic plasticity and is impaired by predator scent stress, our results

Mast Cell Proteases 6 and 7 Stimulate Angiogenesis by Inducing Endothelial Cells to Release Angiogenic Factors

PubMed Central

de Souza, Devandir Antonio; Borges, Antonio Carlos; Santana, Ana Carolina; Oliver, Constance; Jamur, Maria Célia

2015-01-01

Mast cell proteases are thought to be involved with tumor progression and neo-vascularization. However, their exact role is still unclear. The present study was undertaken to further elucidate the function of specific subtypes of recombinant mouse mast cell proteases (rmMCP-6 and 7) in neo-vascularization. SVEC4-10 cells were cultured on Geltrex® with either rmMCP-6 or 7 and tube formation was analyzed by fluorescence microscopy and scanning electron microscopy. Additionally, the capacity of these proteases to induce the release of angiogenic factors and pro and anti-angiogenic proteins was analyzed. Both rmMCP-6 and 7 were able to stimulate tube formation. Scanning electron microscopy showed that incubation with the proteases induced SVEC4-10 cells to invade the gel matrix. However, the expression and activity of metalloproteases were not altered by incubation with the mast cell proteases. Furthermore, rmMCP-6 and rmMCP-7 were able to induce the differential release of angiogenic factors from the SVEC4-10 cells. rmMCP-7 was more efficient in stimulating tube formation and release of angiogenic factors than rmMCP-6. These results suggest that the subtypes of proteases released by mast cells may influence endothelial cells during in vivo neo-vascularization. PMID:26633538

Ventilation-induced release of phosphatidylcholine from neonatal-rat lungs in vitro.

PubMed Central

Nijjar, M S

1984-01-01

Factors regulating the release of phosphatidylcholine (PC) from neonatal-rat lungs were investigated. The results show that the release of prelabelled PC from the newborn-rat lung was augmented by air ventilation at the onset of breathing. This response was mimicked in lungs of pups delivered 1 day before term and allowed to breathe for different time intervals. Anoxia further augmented the ventilation-enhanced PC release from the newborn-rat lungs. The ventilation-induced release of PC was not abolished by the prior treatment of pups in utero or mothers in vivo with phenoxybenzamine, propranolol or atropine, suggesting the lack of receptor stimulation in the ventilation-enhanced PC release at birth. The results also show that ventilation stimulated [methyl-14C]choline incorporation into lung PC, presumably to replenish the depleted surfactant stores. The ratio of adenylate cyclase/cyclic AMP phosphodiesterase activities, which reflects cyclic AMP levels in the developing rat lungs, did not change during the 120 min of air ventilation when the release of PC was much enhanced, implying that cyclic AMP may not be involved. This confirms our conclusion that stimulation of beta-adrenergic receptor was not involved in the air-ventilation-enhanced release of PC. Since the cell number or size did not change during 120 min of ventilation when the alveolar-cell surface was maximally distended, it is suggested that distension of alveolar wall by air ventilation at the onset of breathing may bring the lamellar bodies containing surfactant close to the luminal surface of alveolar type II cells, thereby enhancing their fusion and extrusion by exocytosis. PMID:6477485

Differential involvement of IL-6 in the early and late phase of 1-methylnicotinamide (MNA) release in Concanavalin A-induced hepatitis.

PubMed

Sternak, Magdalena; Jakubowski, Andrzej; Czarnowska, Elzbieta; Slominska, Ewa M; Smolenski, Ryszard T; Szafarz, Malgorzata; Walczak, Maria; Sitek, Barbara; Wojcik, Tomasz; Jasztal, Agnieszka; Kaminski, Karol; Chlopicki, Stefan

2015-09-01

Exogenous 1-methylnicotinamide (MNA) displays anti-inflammatory activity. The aim of this work was to characterize the profile of release of endogenous MNA during the initiation and progression of murine hepatitis induced by Concanavalin A (ConA). In particular we aimed to clarify the role of interleukin-6 (IL-6) as well as the energy state of hepatocytes in MNA release in early and late phases of ConA-induced hepatitis in mice. Hepatitis was induced by ConA in IL-6(+/+) and IL-6(-/-) mice, and various parameters of liver inflammation and injury, as well as the energy state of hepatocytes, were analysed in relation to MNA release. The decrease in ATP/ADP and NADH/NAD ratios, cytokine release (IL-6, IFN-ɤ), acute phase response (e.g. haptoglobin) and liver injury (alanine aminotransaminase, ALT) were all blunted in ConA-induced hepatitis in IL-6(-/-) mice as compared to IL-6(+/+) mice. The release of MNA in response to Con A was also significantly blunted in IL-6(-/-) mice as compared to IL-6(+/+) mice in the early stage of ConA-induced hepatitis. In turn, nicotinamide N-methyltransferase (NNMT) and aldehyde oxidase (AO) activities were blunted in the liver and MNA plasma concentration was elevated to similar degree in the late stage after Concanavalin A in IL-6(+/+) and IL-6(-/-) mice. In conclusion, we demonstrated that in ConA-induced hepatitis, early, but not late MNA release was IL-6-dependent. Our results suggest that in the initiation and early hepatitis, MNA release is linked to the energy deficit/impaired redox status in hepatocytes, while in a later phase, MNA release is rather linked to the systemic inflammation. Copyright © 2015 Elsevier B.V. All rights reserved.

Nerve growth factor alters microtubule targeting agent-induced neurotransmitter release but not MTA-induced neurite retraction in sensory neurons.

PubMed

Pittman, Sherry K; Gracias, Neilia G; Fehrenbacher, Jill C

2016-05-01

Peripheral neuropathy is a dose-limiting side effect of anticancer treatment with the microtubule-targeted agents (MTAs), paclitaxel and epothilone B (EpoB); however, the mechanisms by which the MTAs alter neuronal function and morphology are unknown. We previously demonstrated that paclitaxel alters neuronal sensitivity, in vitro, in the presence of nerve growth factor (NGF). Evidence in the literature suggests that NGF may modulate the neurotoxic effects of paclitaxel. Here, we examine whether NGF modulates changes in neuronal sensitivity and morphology induced by paclitaxel and EpoB. Neuronal sensitivity was assessed using the stimulated release of calcitonin gene-related peptide (CGRP), whereas morphology of established neurites was evaluated using a high content screening system. Dorsal root ganglion cultures, maintained in the absence or presence of NGF, were treated from day 7 to day 12 in culture with paclitaxel (300nM) or EpoB (30nM). Following treatment, the release of CGRP was stimulated using capsaicin or high extracellular potassium. In the presence of NGF, EpoB mimicked the effects of paclitaxel: capsaicin-stimulated release was attenuated, potassium-stimulated release was slightly enhanced and the total peptide content was unchanged. In the absence of NGF, both paclitaxel and EpoB decreased capsaicin- and potassium-stimulated release and the total peptide content, suggesting that NGF may reverse MTA-induced hyposensitivity. Paclitaxel and EpoB both decreased neurite length and branching, and this attenuation was unaffected by NGF in the growth media. These differential effects of NGF on neuronal sensitivity and morphology suggest that neurite retraction is not a causative factor to alter neuronal sensitivity. Copyright © 2016 Elsevier Inc. All rights reserved.

Paclitaxel-induced peripheral neuropathy increases substance P release in rat spinal cord.

PubMed

Chiba, Terumasa; Oka, Yusuke; Kambe, Toshie; Koizumi, Naoya; Abe, Kenji; Kawakami, Kazuyoshi; Utsunomiya, Iku; Taguchi, Kyoji

2016-01-05

Peripheral neuropathy is a common adverse effect of paclitaxel treatment. The major dose-limiting side effect of paclitaxel is peripheral sensory neuropathy, which is characterized by painful paresthesia of the hands and feet. To analyze the contribution of substance P to the development of paclitaxel-induced mechanical hyperalgesia, substance P expression in the superficial layers of the rat spinal dorsal horn was analyzed after paclitaxel treatment. Behavioral assessment using the von Frey test and the paw thermal test showed that intraperitoneal administration of 2 and 4mg/kg paclitaxel induced mechanical allodynia/hyperalgesia and thermal hyperalgesia 7 and 14 days after treatment. Immunohistochemistry showed that paclitaxel (4mg/kg) treatment significantly increased substance P expression (37.6±3.7% on day 7, 43.6±4.6% on day 14) in the superficial layers of the spinal dorsal horn, whereas calcitonin gene-related peptide (CGRP) expression was unchanged. Moreover, paclitaxel (2 and 4mg/kg) treatment significantly increased substance P release in the spinal cord on day 14. These results suggest that paclitaxel treatment increases release of substance P, but not CGRP in the superficial layers of the spinal dorsal horn and may contribute to paclitaxel-induced painful peripheral neuropathy. Copyright © 2015 Elsevier B.V. All rights reserved.

Kinetic Studies of Calcium-Induced Calcium Release in Cardiac Sarcoplasmic Reticulum Vesicles

PubMed Central

Sánchez, Gina; Hidalgo, Cecilia; Donoso, Paulina

2003-01-01

Fast Ca2+ release kinetics were measured in cardiac sarcoplasmic reticulum vesicles actively loaded with Ca2+. Release was induced in solutions containing 1.2 mM free ATP and variable free [Ca2+] and [Mg2+]. Release rate constants (k) were 10-fold higher at pCa 6 than at pCa 5 whereas Ryanodine binding was highest at pCa ≤5. These results suggest that channels respond differently when exposed to sudden [Ca2+] changes than when exposed to Ca2+ for longer periods. Vesicles with severalfold different luminal calcium contents exhibited double exponential release kinetics at pCa 6, suggesting that channels undergo time-dependent activity changes. Addition of Mg2+ produced a marked inhibition of release kinetics at pCa 6 (K0.5 = 63 μM) but not at pCa 5. Coexistence of calcium activation and inhibition sites with equally fast binding kinetics is proposed to explain this behavior. Thimerosal activated release kinetics at pCa 5 at all [Mg2+] tested and increased at pCa 6 the K0.5 for Mg2+ inhibition, from 63 μM to 136 μM. We discuss the possible relevance of these results, which suggest release through RyR2 channels is subject to fast regulation by Ca2+ and Mg2+ followed by time-dependent regulation, to the physiological mechanisms of cardiac channel opening and closing. PMID:12668440

Mechanical load induces sarcoplasmic wounding and FGF release in differentiated human skeletal muscle cultures

NASA Technical Reports Server (NTRS)

Clarke, M. S.; Feeback, D. L.

1996-01-01

The transduction mechanism (or mechanisms) responsible for converting a mechanical load into a skeletal muscle growth response are unclear. In this study we have used a mechanically active tissue culture model of differentiated human skeletal muscle cells to investigate the relationship between mechanical load, sarcolemma wounding, fibroblast growth factor release, and skeletal muscle cell growth. Using the Flexcell Strain Unit we demonstrate that as mechanical load increases, so too does the amount of sarcolemma wounding. A similar relationship was also observed between the level of mechanical load inflicted on the cells and the amount of bFGF (FGF2) released into the surrounding medium. In addition, we demonstrate that the muscle cell growth response induced by chronic mechanical loading in culture can be inhibited by the presence of an antibody capable of neutralizing the biological activity of FGF. This study provides direct evidence that mechanically induced, sarcolemma wound-mediated FGF release is an important autocrine mechanism for transducing the stimulus of mechanical load into a skeletal muscle growth response.

Role of IL-1 beta and COX2 in silica-induced IL-6 release and loss of pneumocytes in co-cultures.

PubMed

Herseth, Jan I; Refsnes, Magne; Låg, Marit; Schwarze, Per E

2009-10-01

The pro-inflammatory cytokines IL-1 beta, TNF-alpha and IL-6 are of great importance in the development of silica-induced lung damage and repair. In this study we investigated the role of IL-1 beta, TNF-alpha and COX2 in silica-induced regulation of IL-6 release and pneumocyte loss in various mono- and co-cultures of monocytes, pneumocytes and endothelial cells. All co-cultures with monocytes, and especially cultures including endothelial cells, showed an increase of silica-induced release of IL-6 compared to the respective monocultures. Treatment with the antagonist IL-1 ra strongly decreased IL-1 beta and IL-6 release in contact co-cultures of monocytes and pneumocytes. COX2 up-regulation by silica and IL-1 beta was eliminated by IL-1 ra. Inhibition of COX2 markedly reduced both IL-1 beta and IL-6 release. IL-1 ra was more effective than COX2-inhibition in reduction of IL-6, but not of IL-1 beta. Silica-induced pneumocyte loss was reduced by IL-1 beta, but this effect was not counteracted by the IL-1 receptor antagonist. Our findings suggest that silica-induced IL-6 release from pneumocytes is mainly mediated via IL-1 beta release from the monocytes, via both COX2-dependent and -independent pathways. Notably, COX2-derived mediators seem crucial for a positive feed-back regulation of IL-1 beta release from the monocytes. In contrast to silica-induced IL-6, the reduction in pneumocyte loss by IL-1 beta does not seem to be regulated through an IL-1R1-dependent mechanism.

Anoxia-induced release of colloid- and nanoparticle-bound phosphorus in grassland soils.

PubMed

Henderson, R; Kabengi, N; Mantripragada, N; Cabrera, M; Hassan, S; Thompson, A

2012-11-06

Particle-facilitated transport is a key mechanism of phosphorus (P) loss in agroecosystems. We assessed contributions of colloid- and nanoparticle-bound P (nPP; 1-415 nm) to total P released from grassland soils receiving biannual poultry litter applications since 1995. In laboratory incubations, soils were subjected to 7 days of anoxic conditions or equilibrated at pH 6 and 8 under oxic conditions and then the extract was size fractionated by differential centrifugation/ultrafiltration for analysis of P, Al, Fe, Si, Ti, and Ca. Selected samples were characterized by transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) and field flow fractionation (FFF-ICP-MS). Particles released were present as nanoaggregates with a mean diameter of 200-250 nm, composed of ~50-nm aluminosilicate flakes studded with Fe and Ti-rich clusters (<10 nm) that contained most of the P detected by EDS. Anoxic incubation of stimulated nPP release with seasonally saturated soils released more nPP and Fe(2+)(aq) than well-drained soils; whereas, nonreductive particle dispersion, accomplished by raising the pH, yielded no increase in nPP release. This suggests Fe acts as a cementing agent, binding to the bulk soil P-bearing colloids that can be released during reducing conditions. Furthermore, it suggests prior periodic exposure to anoxic conditions increases susceptibility to redox-induced P mobilization.

Neutrophil extracellular traps release induced by Leishmania: role of PI3Kγ, ERK, PI3Kσ, PKC, and [Ca2+

PubMed Central

DeSouza-Vieira, Thiago; Guimarães-Costa, Anderson; Rochael, Natalia C.; Lira, Maria N.; Nascimento, Michelle T.; Lima-Gomez, Phillipe de Souza; Mariante, Rafael M.; Persechini, Pedro M.; Saraiva, Elvira M.

2016-01-01

Upon in vitro stimulation, neutrophils undergo a cell death named netosis. This process is characterized by extracellular release of chromatin scaffold associated with granular and cytoplasmic proteins, which together, ensnare and kill microbes. We have previously described that interaction of Leishmania amazonensis with human neutrophils leads to the release of neutrophil extracellular traps, which trap and kill the parasite. However, the signaling leading to Leishmania induced netosis is still unknown. Thus, we sought to evaluate signaling events that drive L. amazonensis induced neutrophil extracellular trap release from human neutrophils. Here, we found that PI3K, independently of protein kinase B, has a role in parasite-induced netosis. We also described that the main isoforms involved are PI3Kγ and PI3Kδ, which work in reactive oxygen species-dependent and -independent ways, respectively. We demonstrated that activation of ERK downstream of PI3Kγ is important to trigger reactive oxygen species-dependent, parasite-induced netosis. Pharmacological inhibition of protein kinase C also significantly decreased parasite-induced neutrophil extracellular trap release. Intracellular calcium, regulated by PI3Kδ, represents an alternative reactive oxygen species-independent pathway of netosis stimulated by L. amazonensis. Finally, intracellular calcium mobilization and reactive oxygen species generation are the major regulators of parasite-induced netosis. Our results contribute to a better understanding of the signaling behind netosis induced by interactions between Leishmania and neutrophils. PMID:27154356

Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils.

PubMed

LeMonte, Joshua J; Stuckey, Jason W; Sanchez, Joshua Z; Tappero, Ryan; Rinklebe, Jörg; Sparks, Donald L

2017-06-06

Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions. We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.

Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils

DOE PAGES

LeMonte, Joshua J.; Stuckey, Jason W.; Sanchez, Joshua Z.; ...

2017-05-04

Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions.more » We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Here, our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.« less

Sea Level Rise Induced Arsenic Release from Historically Contaminated Coastal Soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

LeMonte, Joshua J.; Stuckey, Jason W.; Sanchez, Joshua Z.

Climate change-induced perturbations in the hydrologic regime are expected to impact biogeochemical processes, including contaminant mobility and cycling. Elevated levels of geogenic and anthropogenic arsenic are found along many coasts around the world, most notably in south and southeast Asia but also in the United States, particularly along the Mid-Atlantic coast. The mechanism by and the extent to which arsenic may be released in contaminated coastal soils due to sea level rise are unknown. Here we show a series of data from a coastal arsenic-contaminated soil exposed to sea and river waters in biogeochemical microcosm reactors across field-validated redox conditions.more » We find that reducing conditions lead to arsenic release from historically contaminated coastal soils through reductive dissolution of arsenic-bearing mineral oxides in both sea and river water inundations, with less arsenic release from seawater scenarios than river water due to inhibition of oxide dissolution. For the first time, we systematically display gradation of solid phase soil-arsenic speciation across defined redox windows from reducing to oxidizing conditions in natural waters by combining biogeochemical microcosm experiments and X-ray absorption spectroscopy. Here, our results demonstrate the threat of sea level rise stands to impact arsenic release from contaminated coastal soils by changing redox conditions.« less

Forced swimming-induced oxytocin release into blood and brain: Effects of adrenalectomy and corticosterone treatment.

PubMed

Torner, Luz; Plotsky, Paul M; Neumann, Inga D; de Jong, Trynke R

2017-03-01

The oxytocin (OXT) system is functionally linked to the HPA axis in a reciprocal and complex manner. Certain stressors are known to cause the simultaneous release of OXT and adrenocorticotrophic hormone (ACTH) followed by corticosterone (CORT). Furthermore, brain OXT attenuates ACTH and CORT responses. Although there are some indications of CORT influencing OXT neurotransmission, specific effects of CORT on neurohypophyseal or intra-hypothalamic release of OXT have not been studied in detail. In the present set of experiments, adult male rats were adrenalectomized (ADX) or sham-operated and fitted with a jugular vein catheter and/or microdialysis probe targeting the hypothalamic paraventricular nucleus (PVN). Blood samples and dialysates were collected before and after forced swimming (FS) and analyzed for CORT, ACTH and AVP concentrations (in plasma) and OXT concentrations (in plasma and dialysates). Experimental treatments included acute infusion of CORT (70 or 175μg/kg i.v.) 5min prior to FS, or subcutaneous placement of 40% CORT pellets resulting in stable CORT levels in the normal basal range. Although ADX did not alter basal OXT concentrations either in plasma or in microdialysates from the PVN, it did cause an exaggerated peripheral secretion of OXT and a blunted intra-PVN release of OXT in response to FS. CORT pellets did not influence either of these ADX-induced effects, while acute infusion of 175μg/kg CORT rescued the stress-induced rise in OXT release within the PVN and modestly increased peripheral OXT secretion. In conclusion, these results indicate that CORT regulates both peripheral and intracerebral OXT release, but in an independent manner. Whereas the peripheral secretion of OXT occurs simultaneously to HPA axis activation in response to FS and is modestly influenced by CORT, HPA axis activation and circulating CORT strongly contribute to the stress-induced stimulation of OXT release within the PVN. Copyright © 2016 Elsevier Ltd. All rights

Novel hydrogen sulfide-releasing compound, S-propargyl-cysteine, prevents STZ-induced diabetic nephropathy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Xin; Li, Xinghui; Ma, Fenfen

2016-05-13

In this work, we demonstrated for the first time that S-propargyl-cysteine (SPRC, also named as ZYZ-802), a novel hydrogen sulfide (H{sub 2}S)-releasing compound, had renoprotective effects on streptozotocin (STZ)-induced diabetic kidney injury. SPRC treatment significantly reduced the level of creatinine, kidney to body weight ratio and in particular, markedly decreased 24-h urine microalbuminuria excretion. SPRC suppressed the mRNA expression of fibronectin and type IV collagen. In vitro, SPRC inhibited mesangial cells over-proliferation and hypertrophy induced by high glucose. Additionally, SPRC attenuated inflammation in diabetic kidneys. SPRC also reduced transforming growth factor β1 (TGF-β1) signaling and expression of phosphorylated Smad3 (p-Smad3) pathway. Moreover,more » SPRC inhibited phosphorylation of ERK, p38 protein. Taken together, SPRC was demonstrated to be a potential therapeutic candidate to suppress diabetic nephropathy. - Highlights: • We synthesized a novel hydrogen sulfide-releasing compound, S-propargyl-cysteine (SPRC). • SPRC was preliminarily demonstrated to prevent STZ-induced diabetic nephropathy (DN). • SPRC may exert potential therapeutic candidate to suppress DN.« less

Identified Serotonin-Releasing Neurons Induce Behavioral Quiescence and Suppress Mating in Drosophila.

PubMed

Pooryasin, Atefeh; Fiala, André

2015-09-16

Animals show different levels of activity that are reflected in sensory responsiveness and endogenously generated behaviors. Biogenic amines have been determined to be causal factors for these states of arousal. It is well established that, in Drosophila, dopamine and octopamine promote increased arousal. However, little is known about factors that regulate arousal negatively and induce states of quiescence. Moreover, it remains unclear whether global, diffuse modulatory systems comprehensively affecting brain activity determine general states of arousal. Alternatively, individual aminergic neurons might selectively modulate the animals' activity in a distinct behavioral context. Here, we show that artificially activating large populations of serotonin-releasing neurons induces behavioral quiescence and inhibits feeding and mating. We systematically narrowed down a role of serotonin in inhibiting endogenously generated locomotor activity to neurons located in the posterior medial protocerebrum. We identified neurons of this cell cluster that suppress mating, but not feeding behavior. These results suggest that serotonin does not uniformly act as global, negative modulator of general arousal. Rather, distinct serotoninergic neurons can act as inhibitory modulators of specific behaviors. An animal's responsiveness to external stimuli and its various types of endogenously generated, motivated behavior are highly dynamic and change between states of high activity and states of low activity. It remains unclear whether these states are mediated by unitary modulatory systems globally affecting brain activity, or whether distinct neurons modulate specific neuronal circuits underlying particular types of behavior. Using the model organism Drosophila melanogaster, we find that activating large proportions of serotonin-releasing neurons induces behavioral quiescence. Moreover, distinct serotonin-releasing neurons that we genetically isolated and identified negatively affect

Antagonistic effects of beta-phenylethylamine on quinpirole- and (-)-sulpiride-induced changes in evoked dopamine release from rat striatal slices.

PubMed

Yamada, S; Harano, M; Tanaka, M

1998-02-19

To assess the role of beta-phenylethylamine in aspects of dopamine release, we measured the level of beta-phenylethylamine in the rat striatum after killing the rats by microwave irradiation. We then investigated the effect of beta-phenylethylamine on electrically evoked dopamine release from rat striatal slices in vitro. The striatal beta-phenylethylamine level was 46.5 +/- 3.5 ng/g wet tissue, equivalent to 0.3 micromol/l. Superfusion with low concentrations of beta-phenylethylamine up to 1 micromol/l had no effect on spontaneous or electrically evoked dopamine release from striatal slices. Quinpirole reduced the evoked dopamine release from slices in a concentration-dependent manner. The quinpirole-induced reduction of evoked dopamine release was attenuated 30% by superfusion with 0.3 micromol/l beta-phenylethylamine. Moreover, the (-)-sulpiride (0.1 micromol/l)-induced increase in evoked dopamine release was also attenuated by superfusion with 0.3 micromol/l beta-phenylethylamine. These data indicate that submicromolar levels of beta-phenylethylamine could modify the dopamine autoreceptor mediated changes in evoked dopamine release from rat striatal slices.

Mechanical stretch-induced serotonin release from pulmonary neuroendocrine cells: implications for lung development.

PubMed

Pan, Jie; Copland, Ian; Post, Martin; Yeger, Herman; Cutz, Ernest

2006-01-01

Pulmonary neuroendocrine cells (PNEC) produce amine (serotonin, 5-HT) and peptides (e.g., bombesin, calcitonin) with growth factor-like properties and are thought to play an important role in lung development. Because physical forces are essential for lung growth and development, we investigated the effects of mechanical strain on 5-HT release in PNEC freshly isolated from rabbit fetal lung and in the PNEC-related tumor H727 cell line. Cultures exposed to sinusoidal cyclic stretch showed a significant 5-HT release inhibitable with gadolinium chloride (10 nM), a blocker of mechanosensitive channels. In contrast to hypoxia (Po2 approximately 20 mmHg), stretch-induced 5-HT release was not affected by Ca2+-free medium or nifedipine (50 microM), excluding the exocytic pathway. In H727 cells, stretch failed to release calcitonin, a peptide stored within dense core vesicles (DCV), whereas hypoxia caused massive calcitonin release. 5-HT released by mechanical stretch is derived predominantly from the cytoplasmic pool, because it is rapid ( approximately 5 min) and is releasable from early (20 days of gestation) fetal PNEC containing few DCV. Both mechanical stretch and hypoxia upregulated expression of tryptophan hydroxylase, the rate-limiting enzyme of 5-HT synthesis. We conclude that mechanical strain is an important physiological stimulus for the release of 5-HT from PNEC via mechanosensitive channels with potential effects on lung development and resorption of lung fluid at the time of birth.

Recharge of the early atmosphere of Mars by impact-induced release of CO2

USGS Publications Warehouse

Carr, Michael H.

1989-01-01

Channels on the Martian surface suggest that Mars had an early, relatively thick atmosphere. If the atmosphere was thick enough for water to be stable at the surface, CO2 in the atmosphere would have been fixed as carbonates on a relatively short time scale, previously estimated to be 1 bar every 107 years. This loss must have been offset by some replenishment mechanism to account for the numerous valley networks in the oldest surviving terrains. Impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by addition of carbon to Mars from the impacting bolides. Depending on the relationship between the transient cavity diameter and the diameter of the resulting crater, burial rates as a result of impact gardening at the end of heavy bombardment are estimated to range from 20 to 45 m/106 years, on the assumption that cratering rates in Mars were similar to those of the Nectarian Period on the Moon. At these rates 0.1-0.2 bar of CO2 could have been released every 107 years as a result of burial to depths where dissociation temperatures of carbonates were reached. Modeling of large impacts suggests that an additional 0.01 to 0.02 bar of CO2 could have been released every 107 years during the actual impacts. In the unlikely event that all the impacting material was composed of carbonaceous chondrites, a further 0.3 bar of CO2 could have been added to the atmosphere every 107 years by oxidation of meteoritic carbon. Even when supplemented by the volcanically induced release of CO2, these release rates are barely sufficient to sustain an early atmosphere if water were continuously present at the surface. The results suggest that water may have been only intermittently present on the surface early in the planet's history.

Host DNA released by NETosis promotes rhinovirus-induced type 2 allergic asthma exacerbation

PubMed Central

Toussaint, Marie; Jackson, David J; Swieboda, Dawid; Guedán, Anabel; Tsourouktsoglou, Theodora-Dorita; Ching, Yee Man; Radermecker, Coraline; Makrinioti, Heidi; Aniscenko, Julia; Edwards, Michael R; Solari, Roberto; Farnir, Frédéric; Papayannopoulos, Venizelos; Bureau, Fabrice; Marichal, Thomas; Johnston, Sebastian L

2018-01-01

Respiratory viral infections represent the most common cause of allergic asthma exacerbations. Amplification of type 2 immune response is strongly implicated in asthma exacerbation, but how virus infection boosts type 2 responses is poorly understood. We report a significant correlation between release of host double stranded DNA (dsDNA) following rhinovirus infection and exacerbation of type 2 allergic inflammation in humans. In a mouse model of allergic airway hypersensitivity, we show that rhinovirus infection triggers dsDNA release associated with neutrophil extracellular traps (NETs) formation (NETosis). We further demonstrate that inhibiting NETosis by blocking neutrophil elastase, or degrading NETs with DNase protects mice from type 2 immunopathology. Furthermore, injection of mouse genomic DNA alone is sufficient to recapitulate many features of rhinovirus-induced type 2 immune responses and asthma pathology. Thus, NETosis and its associated extracellular dsDNA contribute to the pathogenesis and may represent potential therapeutic targets of rhinovirus-induced asthma exacerbations. PMID:28459437

The total kinetic energy release in the fast neutron-induced fission of 232Th

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, Jonathan; Yanez, Ricardo; Loveland, Walter

Here, the post-emission total kinetic energy release (TKE) in the neutron-induced fission of 232Th was measured (using white spectrum neutrons from LANSCE) for neutron energies from E n=3 to 91MeV. In this energy range the average post-neutron total kinetic energy release decreases from 162.3±0.3 at E n=3 MeV to 154.9±0.3 MeV at E n=91 MeV. Analysis of the fission mass distributions indicates that the decrease in TKE with increasing neutron energy is a combination of increasing yields of symmetric fission (which has a lower associated TKE) and a decrease in the TKE release in asymmetric fission.

The total kinetic energy release in the fast neutron-induced fission of 232Th

DOE PAGES

King, Jonathan; Yanez, Ricardo; Loveland, Walter; ...

2017-12-15

Here, the post-emission total kinetic energy release (TKE) in the neutron-induced fission of 232Th was measured (using white spectrum neutrons from LANSCE) for neutron energies from E n=3 to 91MeV. In this energy range the average post-neutron total kinetic energy release decreases from 162.3±0.3 at E n=3 MeV to 154.9±0.3 MeV at E n=91 MeV. Analysis of the fission mass distributions indicates that the decrease in TKE with increasing neutron energy is a combination of increasing yields of symmetric fission (which has a lower associated TKE) and a decrease in the TKE release in asymmetric fission.

NET formation induced by Pseudomonas aeruginosa cystic fibrosis isolates measured as release of myeloperoxidase-DNA and neutrophil elastase-DNA complexes.

PubMed

Yoo, Dae-goon; Floyd, Madison; Winn, Matthew; Moskowitz, Samuel M; Rada, Balázs

2014-08-01

Cystic fibrosis (CF) airway disease is characterized by Pseudomonas aeruginosa infection and recruitment of neutrophil granulocytes. Neutrophil granule components (myeloperoxidase (MPO), human neutrophil elastase (HNE)), extracellular DNA and P. aeruginosa can all be found in the CF respiratory tract and have all been associated with worsening CF lung function. Pseudomonas-induced formation of neutrophil extracellular traps (NETs) offers a likely mechanism for release of MPO, HNE and DNA from neutrophils. NETs are composed of a DNA backbone decorated with granule proteins like MPO and HNE. Here we sought to examine whether CF clinical isolates of Pseudomonas are capable of inducing NET release from human neutrophil granulocytes. We used two methods to quantify NETs. We modified a previously employed ELISA that detects MPO-DNA complexes and established a new HNE-DNA ELISA. We show that these methods reliably quantify MPO-DNA and HNE-DNA complexes, measures of NET formation. We have found that CF isolates of P. aeruginosa stimulate robust respiratory burst and NET release in human neutrophils. By comparing paired "early" and "late" bacterial isolates obtained from the same CF patient we have found that early isolates induced significantly more NET release than late isolates. Our data support that Pseudomonas-induced NET release represents an important mechanism for release of neutrophil-derived CF inflammatory mediators, and confirm that decreased induction of NET formation is required for long-term adaptation of P. aeruginosa to CF airways. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultraviolet radiation-induced interleukin 6 release in HeLa cells is mediated via membrane events in a DNA damage-independent way.

PubMed

Kulms, D; Pöppelmann, B; Schwarz, T

2000-05-19

Evidence exists that ultraviolet radiation (UV) affects molecular targets in the nucleus or at the cell membrane. UV-induced apoptosis was found to be mediated via DNA damage and activation of death receptors, suggesting that nuclear and membrane effects are not mutually exclusive. To determine whether participation of nuclear and membrane components is also essential for other UV responses, we studied the induction of interleukin-6 (IL-6) by UV. Exposing HeLa cells to UV at 4 degrees C, which inhibits activation of surface receptors, almost completely prevented IL-6 release. Enhanced repair of UV-mediated DNA damage by addition of the DNA repair enzyme photolyase did not affect UV-induced IL-6 production, suggesting that in this case membrane events predominant over nuclear effects. UV-induced IL-6 release is mediated via NFkappaB since the NFkappaB inhibitor MG132 or transfection of cells with a super-repressor form of the NFkappaB inhibitor IkappaB reduced IL-6 release. Transfection with a dominant negative mutant of the signaling protein TRAF-2 reduced IL-6 release upon exposure to UV, indicating that UV-induced IL-6 release is mediated by activation of the tumor necrosis factor receptor-1. These data demonstrate that UV can exert biological effects mainly by affecting cell surface receptors and that this is independent of its ability to induce nuclear DNA damage.

Hydrostatic Pressure–Induced Release of Stored Calcium in Cultured Rat Optic Nerve Head Astrocytes

PubMed Central

Mandal, Amritlal; Delamere, Nicholas A.

2010-01-01

Purpose. Elevated intraocular pressure is associated with glaucomatous optic nerve damage. Other investigators have shown functional changes in optic nerve head astrocytes subjected to elevated hydrostatic pressure (HP) for 1 to 5 days. Recently, the authors reported ERK1/2, p90RSK and NHE1 phosphorylation after 2 hours. Here they examine calcium responses at the onset of HP to determine what precedes ERK1/2 phosphorylation. Methods. Cytoplasmic calcium concentration ([Ca2+]i) was measured in cultured rat optic nerve astrocytes loaded with fura-2. The cells were placed in a closed imaging chamber and subjected to an HP increase of 15 mm Hg. Protein phosphorylation was detected by Western blot analysis. Results. The increase of HP caused an immediate slow increase in [Ca2+]i. The response persisted in calcium-free solution and when nickel chloride (4 mM) was added to suppress channel-mediated calcium entry. Previous depletion of the ER calcium stores by cyclopiazonic acid abolished the HP-induced calcium level increase. The HP-induced increase persisted in cells exposed to xestospongin C, an inhibitor of IP3R-mediated calcium release. In contrast, ryanodine receptor (RyR) antagonist ruthenium red (10 μM) or dantrolene (25 μM) inhibited the HP-induced calcium increase. The HP-induced calcium increase was abolished when ryanodine-sensitive calcium stores were pre-depleted with caffeine (3 mM). HP caused ERK1/2 phosphorylation. The magnitude of the ERK1/2 phosphorylation response was reduced by ruthenium red and dantrolene. Conclusions. Increasing HP causes calcium release from a ryanodine-sensitive cytoplasmic store and subsequent ERK1/2 activation. Calcium store release appears to be a required early step in the initial astrocyte response to an HP increase. PMID:20071675

Contraction of small mesenteric arteries induced by micromolar concentrations of ATP released from caged ATP.

PubMed

Sjöblom-Widfeldt, N; Arner, A; Nilsson, H

1993-01-01

The concentration dependence of ATP-induced contractions in isolated resistance arteries was estimated using photolysis of caged ATP. Rat mesenteric vessels were isolated and mounted for force registration in a small chamber allowing illumination from a xenon-flash lamp. Photolysis of 100 microM caged ATP, which released about 20 microM ATP within a few milliseconds in the vessel, induced a transient contraction with an amplitude approximately 40-50% of the response induced by 10 microM noradrenaline. The responses could neither be induced by the light flash as such nor by caged ATP alone nor by photolysis of caged phosphate. The amplitude of the contractions was dependent on the concentration of caged ATP, and the effective concentration for ATP was estimated to be in the range of 1-10 microM. In contrast, when ATP was introduced by diffusion, about a 100-fold higher concentration was required. Thus photolytic release of ATP minimizes metabolism before its action on receptors and reveals action of ATP in a concentration range consistent with a role of ATP as a transmitter in nervous regulation of the tone of resistance vessels.

Shear stress-induced mitochondrial biogenesis decreases the release of microparticles from endothelial cells.

PubMed

Kim, Ji-Seok; Kim, Boa; Lee, Hojun; Thakkar, Sunny; Babbitt, Dianne M; Eguchi, Satoru; Brown, Michael D; Park, Joon-Young

2015-08-01

The concept of enhancing structural integrity of mitochondria has emerged as a novel therapeutic option for cardiovascular disease. Flow-induced increase in laminar shear stress is a potent physiological stimulant associated with exercise, which exerts atheroprotective effects in the vasculature. However, the effect of laminar shear stress on mitochondrial remodeling within the vascular endothelium and its related functional consequences remain largely unknown. Using in vitro and in vivo complementary studies, here, we report that aerobic exercise alleviates the release of endothelial microparticles in prehypertensive individuals and that these salutary effects are, in part, mediated by shear stress-induced mitochondrial biogenesis. Circulating levels of total (CD31(+)/CD42a(-)) and activated (CD62E(+)) microparticles released by endothelial cells were significantly decreased (∼40% for both) after a 6-mo supervised aerobic exercise training program in individuals with prehypertension. In cultured human endothelial cells, laminar shear stress reduced the release of endothelial microparticles, which was accompanied by an increase in mitochondrial biogenesis through a sirtuin 1 (SIRT1)-dependent mechanism. Resveratrol, a SIRT1 activator, treatment showed similar effects. SIRT1 knockdown using small-interfering RNA completely abolished the protective effect of shear stress. Disruption of mitochondrial integrity by either antimycin A or peroxisome proliferator-activated receptor-γ coactivator-1α small-interfering RNA significantly increased the number of total, and activated, released endothelial microparticles, and shear stress restored these back to basal levels. Collectively, these data demonstrate a critical role of endothelial mitochondrial integrity in preserving endothelial homeostasis. Moreover, prolonged laminar shear stress, which is systemically elevated during aerobic exercise in the vessel wall, mitigates endothelial dysfunction by promoting

An alkaline follicular fluid fraction induces capacitation and limited release of oviduct epithelium-bound stallion sperm.

PubMed

Leemans, Bart; Gadella, Bart M; Stout, Tom A E; Nelis, Hilde; Hoogewijs, Maarten; Van Soom, Ann

2015-09-01

Induction of hyperactivated motility is considered essential for triggering the release of oviduct-bound mammalian spermatozoa in preparation for fertilization. In this study, oviduct-bound stallion spermatozoa were exposed for 2 h to: i) pre-ovulatory and ii) post-ovulatory oviductal fluid; iii) 100% and iv) 10% follicular fluid (FF); v) cumulus cells, vi) mature equine oocytes, vii) capacitating and viii) non-capacitating medium. None of these triggered sperm release or hyperactivated motility. Interestingly, native FF was detrimental to sperm viability, an effect that was negated by heat inactivation, charcoal treatment and 30 kDa filtration alone or in combination. Moreover, sperm suspensions exposed to treated FF at pH 7.9 but not pH 7.4 showed Ca(2+)-dependent hypermotility. Fluo-4 AM staining of sperm showed elevated cytoplasmic Ca(2+) in hyperactivated stallion spermatozoa exposed to treated FF at pH 7.9 compared to a modest response in defined capacitating conditions at pH 7.9 and no response in treated FF at pH 7.4. Moreover, 1 h incubation in alkaline, treated FF induced protein tyrosine phosphorylation in 20% of spermatozoa. None of the conditions tested induced widespread release of sperm pre-bound to oviduct epithelium. However, the hyperactivating conditions did induce release of 70-120 spermatozoa per oviduct explant, of which 48% showed protein tyrosine phosphorylation and all were acrosome-intact, but capable of acrosomal exocytosis in response to calcium ionophore. We conclude that, in the presence of elevated pH and extracellular Ca(2+), a heat-resistant, hydrophilic, <30 kDa component of FF can trigger protein tyrosine phosphorylation, elevated cytoplasmic Ca(2+) and hyperactivated motility in stallion sperm, but infrequent release of sperm pre-bound to oviduct epithelium. © 2015 Society for Reproduction and Fertility.

Real-time investigation of cytochrome c release profiles in living neuronal cells undergoing amyloid beta oligomer-induced apoptosis

NASA Astrophysics Data System (ADS)

Lee, Jae Young; Park, Younggeun; Pun, San; Lee, Sung Sik; Lo, Joe F.; Lee, Luke P.

2015-06-01

Intracellular Cyt c release profiles in living human neuroblastoma undergoing amyloid β oligomer (AβO)-induced apoptosis, as a model Alzheimer's disease-associated pathogenic molecule, were analysed in a real-time manner using plasmon resonance energy transfer (PRET)-based spectroscopy.Intracellular Cyt c release profiles in living human neuroblastoma undergoing amyloid β oligomer (AβO)-induced apoptosis, as a model Alzheimer's disease-associated pathogenic molecule, were analysed in a real-time manner using plasmon resonance energy transfer (PRET)-based spectroscopy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02390d

PAR-2 activation enhances weak acid-induced ATP release through TRPV1 and ASIC sensitization in human esophageal epithelial cells.

PubMed

Wu, Liping; Oshima, Tadayuki; Shan, Jing; Sei, Hiroo; Tomita, Toshihiko; Ohda, Yoshio; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

2015-10-15

Esophageal visceral hypersensitivity has been proposed to be the pathogenesis of heartburn sensation in nonerosive reflux disease. Protease-activated receptor-2 (PAR-2) is expressed in human esophageal epithelial cells and is believed to play a role in inflammation and sensation. PAR-2 activation may modulate these responses through adenosine triphosphate (ATP) release, which is involved in transduction of sensation and pain. The transient receptor potential vanilloid receptor 1 (TRPV1) and acid-sensing ion channels (ASICs) are both acid-sensitive nociceptors. However, the interaction among these molecules and the mechanisms of heartburn sensation are still not clear. We therefore examined whether ATP release in human esophageal epithelial cells in response to acid is modulated by TRPV1 and ASICs and whether PAR-2 activation influences the sensitivity of TRPV1 and ASICs. Weak acid (pH 5) stimulated the release of ATP from primary human esophageal epithelial cells (HEECs). This effect was significantly reduced after pretreatment with 5-iodoresiniferatoxin (IRTX), a TRPV1-specific antagonist, or with amiloride, a nonselective ASIC blocker. TRPV1 and ASIC3 small interfering RNA (siRNA) transfection also decreased weak acid-induced ATP release. Pretreatment of HEECs with trypsin, tryptase, or a PAR-2 agonist enhanced weak acid-induced ATP release. Trypsin treatment led to the phosphorylation of TRPV1. Acid-induced ATP release enhancement by trypsin was partially blocked by IRTX, amiloride, or a PAR-2 antagonist. Conversely, acid-induced ATP release was augmented by PAR-2 activation through TRPV1 and ASICs. These findings suggested that the pathophysiology of heartburn sensation or esophageal hypersensitivity may be associated with the activation of PAR-2, TRPV1, and ASICs. Copyright © 2015 the American Physiological Society.

Doxorubicin Release Controlled by Induced Phase Separation and Use of a Co-Solvent.

PubMed

Park, Seok Chan; Yuan, Yue; Choi, Kyoungju; Choi, Seong-O; Kim, Jooyoun

2018-04-26

Electrospun-based drug delivery is emerging as a versatile means of localized therapy; however, controlling the release rates of active agents still remains as a key question. We propose a facile strategy to control the drug release behavior from electrospun fibers by a simple modification of polymer matrices. Polylactic acid (PLA) was used as a major component of the drug-carrier, and doxorubicin hydrochloride (Dox) was used as a model drug. The influences of a polar co-solvent, dimethyl sulfoxide (DMSO), and a hydrophilic polymer additive, polyvinylpyrrolidone (PVP), on the drug miscibility, loading efficiency and release behavior were investigated. The use of DMSO enabled the homogeneous internalization of the drug as well as higher drug loading efficiency within the electrospun fibers. The PVP additive induced phase separation in the PLA matrix and acted as a porogen. Preferable partitioning of Dox into the PVP domain resulted in increased drug loading efficiency in the PLA/PVP fiber. Fast dissolution of PVP domains created pores in the fibers, facilitating the release of internalized Dox. The novelty of this study lies in the detailed experimental investigation of the effect of additives in pre-spinning formulations, such as co-solvents and polymeric porogens, on the drug release behavior of nanofibers.

Doxorubicin Release Controlled by Induced Phase Separation and Use of a Co-Solvent

PubMed Central

Park, Seok Chan; Choi, Kyoungju; Choi, Seong-O

2018-01-01

Electrospun-based drug delivery is emerging as a versatile means of localized therapy; however, controlling the release rates of active agents still remains as a key question. We propose a facile strategy to control the drug release behavior from electrospun fibers by a simple modification of polymer matrices. Polylactic acid (PLA) was used as a major component of the drug-carrier, and doxorubicin hydrochloride (Dox) was used as a model drug. The influences of a polar co-solvent, dimethyl sulfoxide (DMSO), and a hydrophilic polymer additive, polyvinylpyrrolidone (PVP), on the drug miscibility, loading efficiency and release behavior were investigated. The use of DMSO enabled the homogeneous internalization of the drug as well as higher drug loading efficiency within the electrospun fibers. The PVP additive induced phase separation in the PLA matrix and acted as a porogen. Preferable partitioning of Dox into the PVP domain resulted in increased drug loading efficiency in the PLA/PVP fiber. Fast dissolution of PVP domains created pores in the fibers, facilitating the release of internalized Dox. The novelty of this study lies in the detailed experimental investigation of the effect of additives in pre-spinning formulations, such as co-solvents and polymeric porogens, on the drug release behavior of nanofibers. PMID:29701714

Resveratrol inhibits proteinase-activated receptor-2-induced release of soluble vascular endothelial growth factor receptor-1 from human endothelial cells

PubMed Central

Al-Ani, Bahjat

2013-01-01

We recently reported that (i) activation of the proinflammatory receptor, proteinase-activated receptor-2 (PAR-2) caused the release of an important biomarker in preeclampsia, soluble vascular endothelial growth factor receptor-1 (sVEGFR-1, also known as sFlt-1) from human umbilical vein endothelial cells (HUVECs), and (ii) that the anti-oxidant and anti-inflammatory agent, resveratrol, is capable of inhibiting the proinflammatory cytokine-induced sVEGFR-1 release from human placenta. Based on these findings and because PAR-2 is upregulated by proinflammatory cytokines, we sought to determine whether resveratrol can inhibit PAR-2-induced sVEGFR-1 release. PAR-2 expressing cells, HUVECs and human embryonic kidney cells (HEK-293) transfected with a human VEGFR-1 promoter-luciferase reporter construct were incubated with PAR-2-activating peptide and/or resveratrol. Cell supernatants were assayed for sVEGFR-1 by enzyme-linked immunosorbent assay (ELISA), and VEGFR-1 promoter-luciferase assay was performed on the harvested cell lysates. Preincubation of HEK-293 cells with resveratrol significantly inhibited PAR-2-induced VEGFR-1 promoter activity without affecting cell viability as assessed by MTT assay. The addition of resveratrol also blocked PAR-2-mediated sVEGFR-1 release from HUVECs. The present study demonstrates that resveratrol suppressed both VEGFR-1 promoter activity and sVEGFR-1 protein release induced by PAR-2 activation, which further endorses our recent findings of a potential therapeutic role for resveratrol in preeclampsia. PMID:26933402

Recharge of the early atmosphere of Mars by impact-induced release of CO2

NASA Technical Reports Server (NTRS)

Carr, Michael H.

1989-01-01

The question as to whether high impact rates early in the history of Mars could have aided in maintaining a relatively thick CO2 atmosphere is discussed. Such impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by the addition of carbon to Mars from the impacting bolides. On the assumption that cratering rates on Mars were comparable to those of the moon's Nectarial period, burial rates are a result of 'impact gardening' at the end of heavy bombardment are estimated to have ranged from 20 to 45 m/million years; at these rates, 0.1-0.2 bar of CO2 would have been released every 10 million years as a result of burial to depths at which carbonate dissociation temperatures are encountered.

Spinosad induces programmed cell death involves mitochondrial dysfunction and cytochrome C release in Spodoptera frugiperda Sf9 cells.

PubMed

Yang, Mingjun; Wang, Bo; Gao, Jufang; Zhang, Yang; Xu, Wenping; Tao, Liming

2017-02-01

Spinosad, a reduced-risk insecticide, acts on the nicotinic acetylcholine receptors and the gamma-aminobutyric acid receptor in the nervous system of target insects. However, its mechanism of action in non-neural insect cells is unclear. This study aimed to evaluate mitochondrial functional changes associated with spinosad in Spodoptera frugiperda (Sf9) insect cells. Our results indicate that in Sf9 cells, spinosad induces programmed cell death and mitochondrial dysfunction through enhanced reactive oxygen species production, mitochondrial permeability transition pore (mPTP) opening, and mitochondrial membrane potential collapse, eventually leading to cytochrome C release and apoptosis. The cytochrome C release induced by spinosad treatment was partly inhibited by the mPTP inhibitors cyclosporin A and bongkrekic acid. Subsequently, we found that spinosad downregulated Bcl-2 expression and upregulated p53 and Bax expressions, activated caspase-9 and caspase-3, and triggered PARP cleavage in Sf9 cells. These findings suggested that spinosad-induced programmed cell death was modulated by mitochondrial dysfunction and cytochrome C release. Copyright © 2016 Elsevier Ltd. All rights reserved.

The inhibition of cholera toxin-induced 5-HT release by the 5-HT3 receptor antagonist, granisetron, in the rat

PubMed Central

Turvill, J L; Connor, P; Farthing, M J G

2000-01-01

The secretagogue 5-hydroxytryptamine (5-HT) is implicated in the pathophysiology of cholera. 5-HT released from enterochromaffin cells after cholera toxin exposure is thought to activate non-neuronally (5-HT2 dependent) and neuronally (5-HT3 dependent) mediated water and electrolyte secretion. CT-secretion can be reduced by preventing the release of 5-HT. Enterochromaffin cells possess numerous receptors that, under basal conditions, modulate 5-HT release. These include basolateral 5-HT3 receptors, the activation of which is known to enhance 5-HT release. Until now, 5-HT3 receptor antagonists (e.g. granisetron) have been thought to inhibit cholera toxin-induced fluid secretion by blockading 5-HT3 receptors on secretory enteric neurones. Instead we postulated that they act by inhibiting cholera toxin-induced enterochromaffin cell degranulation. Isolated intestinal segments in anaesthetized male Wistar rats, pre-treated with granisetron 75 μg kg−1, lidoocaine 6 mg kg−1 or saline, were instilled with a supramaximal dose of cholera toxin or saline. Net fluid movement was determined by small intestinal perfusion or gravimetry and small intestinal and luminal fluid 5-HT levels were determined by HPLC with fluorimetric detection. Intraluminal 5-HT release was proportional to the reduction in tissue 5-HT levels and to the onset of water and electrolyte secretion, suggesting that luminal 5-HT levels reflect enterochromaffin cell activity. Both lidocaine and granisetron inhibited fluid secretion. However, granisetron alone, and proportionately, reduced 5-HT release. The simultaneous inhibition of 5-HT release and fluid secretion by granisetron suggests that 5-HT release from enterochromaffin cells is potentiated by endogenous 5-HT3 receptors. The accentuated 5-HT release promotes cholera toxin-induced fluid secretion. PMID:10882387

Calcium-Induced Calcium Release during Action Potential Firing in Developing Inner Hair Cells

PubMed Central

Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J.

2015-01-01

In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

Autocrine Regulation of UVA-Induced IL-6 Production via Release of ATP and Activation of P2Y Receptors

PubMed Central

Kawano, Ayumi; Kadomatsu, Remi; Ono, Miyu; Kojima, Shuji; Tsukimoto, Mitsutoshi; Sakamoto, Hikaru

2015-01-01

Extracellular nucleotides, such as ATP, are released from cells in response to various stimuli and act as intercellular signaling molecules through activation of P2 receptors. Exposure to the ultraviolet radiation A (UVA) component of sunlight causes molecular and cellular damage, and in this study, we investigated the involvement of extracellular nucleotides and P2 receptors in the UVA-induced cellular response. Human keratinocyte-derived HaCaT cells were irradiated with a single dose of UVA (2.5 J/cm2), and ATP release and interleukin (IL)-6 production were measured. ATP was released from cells in response to UVA irradiation, and the release was blocked by pretreatment with inhibitors of gap junction hemichannels or P2X7 receptor antagonist. IL-6 production was increased after UVA irradiation, and this increase was inhibited by ecto-nucleotidase or by antagonists of P2Y11 or P2Y13 receptor. These results suggest that UVA-induced IL-6 production is mediated by release of ATP through hemichannels and P2X7 receptor, followed by activation of P2Y11 and P2Y13 receptors. Interestingly, P2Y11 and P2Y13 were associated with the same pattern of IL-6 production, though they trigger different intracellular signaling cascades: Ca2+-dependent and PI3K-dependent, respectively. Thus, IL-6 production in response to UVA-induced ATP release involves at least two distinct pathways, mediated by activation of P2Y11 and P2Y13 receptors. PMID:26030257

Minocycline attenuates both OGD-induced HMGB1 release and HMGB1-induced cell death in ischemic neuronal injury in PC12 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kikuchi, Kiyoshi; Department of Neurosurgery, Omuta City General Hospital, 2-19-1 Takarazaka, Omuta-City, Fukuoka 836-8567; Kawahara, Ko-ichi

2009-07-24

High mobility group box-1 (HMGB1), a non-histone DNA-binding protein, is massively released into the extracellular space from neuronal cells after ischemic insult and exacerbates brain tissue damage in rats. Minocycline is a semisynthetic second-generation tetracycline antibiotic which has recently been shown to be a promising neuroprotective agent. In this study, we found that minocycline inhibited HMGB1 release in oxygen-glucose deprivation (OGD)-treated PC12 cells and triggered the activation of p38mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK1/2). The ERK kinase (MEK)1/2 inhibitor U-0126 and p38MAPK inhibitor SB203580 blocked HMGB1 release in response to OGD. Furthermore, HMGB1 triggered cell death inmore » a dose-dependent fashion. Minocycline significantly rescued HMGB1-induced cell death in a dose-dependent manner. In light of recent observations as well as the good safety profile of minocycline in humans, we propose that minocycline might play a potent neuroprotective role through the inhibition of HMGB1-induced neuronal cell death in cerebral infarction.« less

Is Liver Enzyme Release Really Associated with Cell Necrosis Induced by Oxidant Stress?

PubMed

Contreras-Zentella, Martha Lucinda; Hernández-Muñoz, Rolando

2016-01-01

Hepatic diseases are a major concern worldwide. Increased specific plasma enzyme activities are considered diagnostic features for liver diseases, since enzymes are released into the blood compartment following the deterioration of the organ. Release of liver mitochondrial enzymes is considered strong evidence for hepatic necrosis, which is associated with an increased production of ROS, often leading to greater hepatic lipid peroxidation. Lipotoxic mediators and intracellular signals activated Kupffer cells, which provides evidence strongly suggesting the participation of oxidant stress in acute liver damage, inducing the progression of liver injury to chronic liver damage. Elevated transaminase activities are considered as an index marker of hepatotoxicity, linked to oxidant stress. However, a drastic increase of serum activities of liver enzyme markers ought not necessarily to reflect liver cell death. In fact, increased serum levels of cytoplasmic enzymes have readily been observed after partial hepatectomy (PH) in the regenerating liver of rats. In this regard, we are now showing that in vitro modifications of the oxidant status affect differentially the release of liver enzymes, indicating that this release is a strictly controlled event and not directly related to the onset of oxidant stress of the liver.

Spinal Actions of Lipoxin A4 and 17(R)-Resolvin D1 Attenuate Inflammation-Induced Mechanical Hypersensitivity and Spinal TNF Release

PubMed Central

Abdelmoaty, Sally; Wigerblad, Gustaf; Bas, Duygu B.; Codeluppi, Simone; Fernandez-Zafra, Teresa; El-Awady, El-Sayed; Moustafa, Yasser; Abdelhamid, Alaa El-din S.; Brodin, Ernst; Svensson, Camilla I.

2013-01-01

Lipoxins and resolvins have anti-inflammatory and pro-resolving actions and accumulating evidence indicates that these lipid mediators also attenuate pain-like behavior in a number of experimental models of inflammation and tissue injury-induced pain. The present study was undertaken to assess if spinal administration of lipoxin A4 (LXA4) or 17 (R)-resolvin D1 (17(R)-RvD1) attenuates mechanical hypersensitivity in the carrageenan model of peripheral inflammation in the rat. Given the emerging role of spinal cytokines in the generation and maintenance of inflammatory pain we measured cytokine levels in the cerebrospinal fluid (CSF) after LXA4 or 17(R)-RvD1 administration, and the ability of these lipid metabolites to prevent stimuli-induced release of cytokines from cultured primary spinal astrocytes. We found that intrathecal bolus injection of LXA4 and17(R)-RvD1 attenuated inflammation-induced mechanical hypersensitivity without reducing the local inflammation. Furthermore, both LXA4 and 17(R)-RvD1 reduced carrageenan-induced tumor necrosis factor (TNF) release in the CSF, while only 17(R)-RvD1attenuated LPS and IFN-γ-induced TNF release in astrocyte cell culture. In conclusion, this study demonstrates that lipoxins and resolvins potently suppress inflammation-induced mechanical hypersensitivity, possibly by attenuating cytokine release from spinal astrocytes. The inhibitory effect of lipoxins and resolvins on spinal nociceptive processing puts them in an intriguing position in the search for novel pain therapeutics. PMID:24086560

Glycerogelatin-based ocular inserts of aceclofenac: physicochemical, drug release studies and efficacy against prostaglandin E₂-induced ocular inflammation.

PubMed

Mathurm, Manish; Gilhotra, Ritu Mehra

2011-01-01

An attempt has been made in the present study to formulate soluble ocular inserts of aceclofenac to facilitate the bioavailability of the drug into the eye, as no eye drop solution could be formulated. Glycero-gelatin ocular inserts/films were prepared and physicochemical parameters and drug release profiles of glycerol-gelatin films of aceclofenac were compared with surface cross-linked films of similar compositions. Ocular irritation of the developed formulation was also checked by HET-CAM test and efficacy of the developed formulation against prostaglandin-induced ocular inflammation in rabbit eye was determined. The non-cross-linked films showed poor mechanical, physicochemical properties, and very little potential of sustaining drug release, however cross-linking the films enhanced tensile strength by 70%, but elasticity decreased by 95%. The cross-linked ocular inserts showed less swelling than non-cross-linked. Formulation AF8 (20% gelatin and 70% glycerin, treated by cross-linker for 1 h) demonstrated the longest drug release for 24 h. As per the kinetic models all films showed a constant drug release with Higuchi diffusion mechanism. Formulation was found to be practically non-irritant. The optimized formulation was tested and compared with eye drops of aceclofenac for anti-inflammatory activity in rabbits against PGE₂-induced inflammation. In vivo studies with developed formulation indicated a significant inhibition of PGE₂-induced PMN migration as compared to eye drops. In conclusion, ocular inserts of aceclofenac was found promising as it achieved sustained drug release and better pharmacodynamic activity.

Omega-conotoxin- and nifedipine-insensitive voltage-operated calcium channels mediate K(+)-induced release of pro-thyrotropin-releasing hormone-connecting peptides Ps4 and Ps5 from perifused rat hypothalamic slices.

PubMed

Valentijn, K; Tranchand Bunel, D; Vaudry, H

1992-07-01

The rat thyrotropin-releasing hormone (TRH) precursor (prepro-TRH) contains five copies of the TRH progenitor sequence linked together by intervening sequences. Recently, we have shown that the connecting peptides prepro-TRH-(160-169) (Ps4) and prepro-TRH-(178-199) (Ps5) are released from rat hypothalamic neurones in response to elevated potassium concentrations, in a calcium-dependent manner. In the present study, the role of voltage-operated calcium channels in potassium-induced release of Ps4 and Ps5 was investigated, using a perifusion system for rat hypothalamic slices. The release of Ps4 and Ps5 stimulated by potassium (70 mM) was blocked by the inorganic ions Co2+ (2.6 mM) and Ni2+ (5 mM). In contrast, the stimulatory effect of KCl was insensitive to Cd2+ (100 microM). The dihydropyridine antagonist nifedipine (10 microM) had no effect on K(+)-evoked release of Ps4 and Ps5. Furthermore, the response to KCl was not affected by nifedipine (10 microM) in combination with diltiazem (1 microM), a benzothiazepine which increases the affinity of dihydropyridine antagonists for their receptor. The dihydropyridine agonist BAY K 8644, at concentrations as high as 1 mM, did not stimulate the basal secretion of Ps4 and Ps5. In addition, BAY K 8644 had no potentiating effect on K(+)-induced release of Ps4 and Ps5. The marine cone snail toxin omega-conotoxin, a blocker of both L- and N-type calcium channels had no effect on the release of Ps4 and Ps5 stimulated by potassium. Similarly, the omega-conopeptide SNX-111, a selective blocker of N-type calcium channels, did not inhibit the stimulatory effect of potassium. The release of Ps4 and Ps5 evoked by high K+ was insensitive to the non-selective calcium channel blocker verapamil (20 microM). Amiloride (1 microM), a putative blocker of T-type calcium channels, did not affect KCl-induced secretion of the two connecting peptides. Taken together, these results indicate that two connecting peptides derived from the pro-TRH, Ps

Platelet-rich concentrates differentially release growth factors and induce cell migration in vitro.

PubMed

Schär, Michael O; Diaz-Romero, Jose; Kohl, Sandro; Zumstein, Matthias A; Nesic, Dobrila

2015-05-01

Platelet-rich concentrates are used as a source of growth factors to improve the healing process. The diverse preparation protocols and the gaps in knowledge of their biological properties complicate the interpretation of clinical results. In this study we aimed to (1) analyze the concentration and kinetics of growth factors released from leukocyte- and platelet-rich fibrin (L-PRF), leukocyte- and platelet-rich plasma (L-PRP), and natural blood clot during in vitro culture; (2) investigate the migration of mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as a functional response to the factors released; and (3) uncover correlations between individual growth factors with the initial platelet/leukocyte counts or the induced cell migration. L-PRF, L-PRP, and natural blood clot prepared from 11 donors were cultured in vitro for 28 days and media supernatants collected after 8 hours and 1, 3, 7, 14, and 28 days. Released transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF), insulin growth factor (IGF-1), platelet-derived growth factor AB (PDGF-AB), and interleukin-1β (IL-1β) were measured in the supernatants with enzyme-linked immunosorbent assay. Migration of MSC and HUVEC induced by the supernatants was evaluated in Boyden chambers. More TGF-ß1 was released (mean ± SD in pg/mL of blood) from L-PRF (37,796 ± 5492) compared with L-PRP (23,738 ± 6848; p < 0.001) and blood clot (3739 ± 4690; p < 0.001), whereas more VEGF and IL-1ß were released from blood clot (1933 ± 704 and 2053 ± 908, respectively) compared with both L-PRP (642 ± 208; p < 0.001 and 273 ± 386; p < 0.001, respectively) and L-PRF (852 ± 376; p < 0.001 and 65 ± 56, p < 0.001, respectively). No differences were observed in IGF-1 and PDGF-AB released from any of the concentrates. TGF-β1 release peaked at Day 7 in L-PRF and at 8 hours and Day 7 in L-PRP and 8 hours and Day 14 in blood clot. In all concentrates, main release of VEGF

Effects of Chronic Alcohol Exposure on the Modulation of Ischemia-Induced Glutamate Release via Cannabinoid Receptors in the Dorsal Hippocampus.

PubMed

Zheng, Lei; Wu, Xiaoda; Dong, Xiao; Ding, Xinli; Song, Cunfeng

2015-10-01

Chronic alcohol consumption is a critical contributing factor to ischemic stroke, as it enhances ischemia-induced glutamate release, leading to more severe excitotoxicity and brain damage. But the neural mechanisms underlying this phenomenon are poorly understood. We evaluated the effects of chronic alcohol exposure on the modulation of ischemia-induced glutamate release via CB1 and CB2 cannabinoid receptors during middle cerebral artery occlusion, using in vivo microdialysis coupled with high-performance liquid chromatography, in alcohol-naïve rats or rats after 1 or 30 days of withdrawal from chronic ethanol intake (6% v/v for 14 days). Intra-dorsal hippocampus (DH) infusions of ACEA or JWH133, selective CB1 or CB2 receptor agonists, respectively, decreased glutamate release in the DH in alcohol-naïve rats in a dose-dependent manner. Such an effect was reversed by co-infusions of SR141716A or AM630, selective CB1 or CB2 receptor antagonists, respectively. After 30 days, but not 1 day of withdrawal, ischemia induced an enhancement in glutamate release in the DH, as compared with non-alcohol-treated control group. Intra-DH infusions of JWH133, but not ACEA, inhibited ischemia-induced glutamate release in the DH after 30 days of withdrawal. Finally, 1 day of withdrawal did not alter the protein level of CB1 or CB2 receptors in the DH, as compared to non-alcohol-treated control rats. Whereas 30 days of withdrawal robustly decreased the protein level of CB1 receptors, but failed to alter the protein level of CB2 receptors, in the DH, as compared to non-alcohol-treated control rats. Together, these findings suggest that loss of expression/function of CB1 receptors, but not CB2 receptors in the DH, is correlated with the enhancement of ischemia-induced glutamate release after prolonged alcohol withdrawal. Copyright © 2015 by the Research Society on Alcoholism.

Effect of antioxidant supplementation on exercise-induced cardiac troponin release in cyclists: a randomized trial.

PubMed

Klinkenberg, Lieke J J; Res, Peter T; Haenen, Guido R; Bast, Aalt; van Loon, Luc J C; van Dieijen-Visser, Marja P; Meex, Steven J R

2013-01-01

Cardiac troponin is the biochemical gold standard to diagnose acute myocardial infarction. Interestingly however, elevated cardiac troponin concentrations are also frequently observed during and after endurance-type exercise. Oxidative stress associated with prolonged exercise has been proposed to contribute to cardiac troponin release. Therefore, the aim of this study was to assess the effect of 4 week astaxanthin supplementation (a potent cartenoid antioxidant) on antioxidant capacity and exercise-induced cardiac troponin release in cyclists. Thirty-two well-trained male cyclists (age 25±5, weight 73±7 kg, maximum O2 uptake 60±5 mL·kg(-1)·min(-1), Wmax 5.4±0.5 W·kg(-1); mean ± SD) were repeatedly subjected to a laboratory based standardized exercise protocol before and after 4 weeks of astaxanthin (20 mg/day), or placebo supplementation in a double-blind randomized manner. Blood samples were obtained at baseline, at 60 min of cycling and immediately post-exercise (≈ 120 min). The pre-supplementation cycling trial induced a significant rise of median cardiac troponin T concentrations from 3.2 (IQR 3.0-4.2) to 4.7 ng/L (IQR 3.7-6.7), immediately post-exercise (p<0.001). Four weeks of astaxanthin supplementation significantly increased mean basal plasma astaxanthin concentrations from non-detectable values to 175±86 µg·kg(-1). However, daily astaxanthin supplementation had no effect on exercise-induced cardiac troponin T release (p = 0.24), as measured by the incremental area under the curve. Furthermore, the elevation in basal plasma astaxanthin concentrations was not reflected in changes in antioxidant capacity markers (trolox equivalent antioxidant capacity, uric acid, and malondialdehyde). Markers of inflammation (high-sensitivity C-reactive protein) and exercise-induced skeletal muscle damage (creatine kinase) were equally unaffected by astaxanthin supplementation. Despite substantial increases in plasma astaxanthin concentrations, astaxanthin

Involvement of connexin43 in the infrasonic noise-induced glutamate release by cultured astrocytes.

PubMed

Jiang, Shan; Wang, Yong-Qiang; Xu, Cheng-Feng; Li, Ya-Na; Guo, Rong; Li, Ling

2014-05-01

Infrasonic noise/infrasound is a type of environmental noise that threatens public health as a nonspecific biological stressor. Glutamate-related excitotoxicity is thought to be responsible for infrasound-induced impairment of learning and memory. In addition to neurons, astrocytes are also capable of releasing glutamate. In the present study, to identify the effect of infrasound on astroglial glutamate release, cultured astrocytes were exposed to infrasound at 16 Hz, 130 dB for different times. We found that infrasound exposure caused a significant increase in glutamate levels in the extracellular fluid. Moreover, blocking the connexin43 (Cx43) hemichannel or gap junction, decreasing the probability of Cx43 being open or inhibiting of Cx43 expression blocked this increase. The results suggest that glutamate release by Cx43 hemichannels/gap junctions is involved in the response of cultured astrocytes to infrasound.

Novel Carvedilol Analogs that Suppress Store Overload Induced Ca2+ Release

PubMed Central

Smith, Chris D.; Wang, Aixia; Vembaiyan, Kannan; Zhang, Jingqun; Xie, Cuihong; Zhou, Qiang; Wu, Guogen; Wayne Chen, S. R.; Back, Thomas G.

2013-01-01

Carvedilol is a uniquely effective drug for the treatment of cardiac arrhythmias in patients with heart failure. This activity is in part due to its ability to inhibit store overload-induced calcium release (SOICR) through the RyR2 channel. We describe the synthesis, characterization and bioassay of ca. 100 compounds based on the carvedilol motif in order to identify features that correlate with and optimize SOICR inhibition. A single cell bioassay was employed based on the RyR2-R4496C mutant HEK-293 cell line, in which calcium release from the endoplasmic reticulum through the defective channel was measured. IC50 values for SOICR inhibition were thus obtained. The compounds investigated contained modifications to the three principal subunits of carvedilol, including the carbazole and catechol moieties, as well as the linker chain containing the β-amino alcohol functionality. The SAR results indicate that significant alterations are tolerated in each of the three subunits. PMID:24124794

GENETIC INFLUENCES ON IN VTIRO PARTICULATE MATTER-INDUCED AIRWAY EPITHELIAL INJURY AND INFLAMMATORY MEDIATOR RELEASE

EPA Science Inventory

GENETIC INFLUENCES ON IN VITRO PARTICULATE MATTER-INDUCED AIRWAY EPITHELIAL INJURY AND INFLAMMATORY MEDIATOR RELEASE.
JA Dye, JH Richards, DA Andrews, UP Kodavanti. US EPA, RTP, NC, USA.

Particulate matter (PM) air pollution is capable of damaging the airway epitheli...

Regulation of the substance P-induced contraction via the release of acetylcholine and gamma-aminobutyric acid in the guinea-pig urinary bladder.

PubMed Central

Shirakawa, J.; Nakanishi, T.; Taniyama, K.; Kamidono, S.; Tanaka, C.

1989-01-01

1. The action of substance P (SP) on the release of gamma-aminobutyric acid (GABA) and acetylcholine (ACh) and on contraction were studied in strips of the guinea-pig urinary bladder. Substance P induced a dose-dependent contraction of strips of guinea-pig urinary bladder (EC50 = 1.2 x 10(-9) M). This contraction was not altered by tetrodotoxin, but with a dose of 10(-9) M and less, there was a complete inhibition by 10(-6) M) atropine. Contractions initiated by 3 x 10(-9) M) SP or more were partly inhibited by atropine. The EC50 value of substance P in the presence of atropine was 7.0 x 10(-9) M. 2. Substance P induced a Ca2+-dependent and tetrodotoxin-resistant release of [3H]-acetylcholine (ACh) from strips of urinary bladder preloaded with [3H]-choline (EC50 = 4.9 x 10(-10) M), and this release was antagonized by [D-Pro2,D-Trp7,9] substance P. 3. Bicuculline increased the substance P-induced contraction and the release of [3H]-ACh from the strips. 4. Substance P induced a Ca2+-dependent and tetrodotoxin-sensitive release of [3H]-gamma-aminobutyric acid (GABA) from strips preloaded with [3H]-GABA (EC50 = 2.6 x 10(-9) M), and this release was antagonized by [D-Pro2,D-Trp7,9] substance P. 5. Therefore, substance P appears to exert excitatory effects on the contractility of urinary bladder predominantly by stimulating its own receptor located on the cholinergic nerve terminals. GABA released by substance P inhibits stimulation of the cholinergic neurone. However, the direct action of substance P on the cholinergic neurone is more potent that the indirect action via GABA release. PMID:2479440

The mechanisms how heparin affects the tumor cell induced VEGF and chemokine release from platelets to attenuate the early metastatic niche formation

PubMed Central

Ponert, Jan Moritz; Schwarz, Svenja; Haschemi, Reza; Müller, Jens; Pötzsch, Bernd; Bendas, Gerd

2018-01-01

Metastasis is responsible for the majority of cancer associated fatalities. Tumor cells leaving the primary tumor and entering the blood flow immediately interact with platelets. Activated platelets contribute in different ways to cancer cell survival and proliferation, e.g. in formation of the early metastatic niche by release of different growth factors and chemokines. Here we show that a direct interaction between platelets and MV3 melanoma or MCF7 breast cancer cells induces platelet activation and a VEGF release in citrated plasma that cannot be further elevated by the coagulation cascade and generated thrombin. In contrast, the release of platelet-derived chemokines CXCL5 and CXCL7 depends on both, a thrombin-mediated platelet activation and a direct interaction between tumor cells and platelets. Preincubation of platelets with therapeutic concentrations of unfractionated heparin reduces the tumor cell initiated VEGF release from platelets. In contrast, tumor cell induced CXCL5 and CXCL7 release from platelets was not impacted by heparin pretreatment in citrated plasma. In defibrinated, recalcified plasma, on the contrary, heparin is able to reduce CXCL5 and CXCL7 release from platelets by thrombin inhibition. Our data indicate that different chemokines and growth factors in diverse platelet granules are released in tightly regulated processes by various trigger mechanisms. We show for the first time that heparin is able to reduce the mediator release induced by different tumor cells both in a contact and coagulation dependent manner. PMID:29346400

Ca2+-induced Ca2+ Release Phenomena in Mammalian Sympathetic Neurons Are Critically Dependent on the Rate of Rise of Trigger Ca2+

PubMed Central

Hernández-Cruz, Arturo; Escobar, Ariel L.; Jiménez, Nicolás

1997-01-01

The role of ryanodine-sensitive intracellular Ca2+ stores present in nonmuscular cells is not yet completely understood. Here we examine the physiological parameters determining the dynamics of caffeine-induced Ca2+ release in individual fura-2–loaded sympathetic neurons. Two ryanodine-sensitive release components were distinguished: an early, transient release (TR) and a delayed, persistent release (PR). The TR component shows refractoriness, depends on the filling status of the store, and requires caffeine concentrations ≥10 mM. Furthermore, it is selectively suppressed by tetracaine and intracellular BAPTA, which interfere with Ca2+-mediated feedback loops, suggesting that it constitutes a Ca2+-induced Ca2+-release phenomenon. The dynamics of release is markedly affected when Sr2+ substitutes for Ca2+, indicating that Sr2+ release may operate with lower feedback gain than Ca2+ release. Our data indicate that when the initial release occurs at an adequately fast rate, Ca2+ triggers further release, producing a regenerative response, which is interrupted by depletion of releasable Ca2+ and Ca2+-dependent inactivation. A compartmentalized linear diffusion model can reproduce caffeine responses: When the Ca2+ reservoir is full, the rapid initial Ca2+ rise determines a faster occupation of the ryanodine receptor Ca2+ activation site giving rise to a regenerative release. With the store only partially loaded, the slower initial Ca2+ rise allows the inactivating site of the release channel to become occupied nearly as quickly as the activating site, thereby suppressing the initial fast release. The PR component is less dependent on the store's Ca2+ content. This study suggests that transmembrane Ca2+ influx in rat sympathetic neurons does not evoke widespread amplification by CICR because of its inability to raise [Ca2+] near the Ca2+ release channels sufficiently fast to overcome their Ca2+-dependent inactivation. Conversely, caffeine-induced Ca2+ release can

Phosphorylation of TNF-alpha converting enzyme by gastrin-releasing peptide induces amphiregulin release and EGF receptor activation.

PubMed

Zhang, Qing; Thomas, Sufi M; Lui, Vivian Wai Yan; Xi, Sichuan; Siegfried, Jill M; Fan, Huizhou; Smithgall, Thomas E; Mills, Gordon B; Grandis, Jennifer Rubin

2006-05-02

G protein-coupled receptors induce EGF receptor (EGFR) signaling, leading to the proliferation and invasion of cancer cells. Elucidation of the mechanism of EGFR activation by G protein-coupled receptors may identify new signaling paradigms. A gastrin-releasing peptide (GRP)/GRP receptor-mediated autocrine pathway was previously described in squamous cell carcinoma of head and neck. In the present study, we demonstrate that TNF-alpha converting enzyme (TACE), a disintegrin and metalloproteinse-17, undergoes a Src-dependent phosphorylation that regulates release of the EGFR ligand amphiregulin upon GRP treatment. Further investigation reveals the phosphatidylinositol 3-kinase (PI3-K) as the intermediate of c-Src and TACE, contributing to their association and TACE phosphorylation. Phosphoinositide-dependent kinase 1 (PDK1), a downstream target of PI3-K, has been identified as the previously undescribed kinase to directly phosphorylate TACE upon GRP treatment. These findings suggest a signaling cascade of GRP-Src-PI3-K-PDK1-TACE-amphiregulin-EGFR with multiple points of interaction, translocation, and phosphorylation. Furthermore, knockdown of PDK1 augmented the antitumor effects of the EGFR inhibitor erlotinib, indicating PDK1 as a therapeutic target to improve the clinical response to EGFR inhibitors.

THE AUTOCRINE ROLE OF TRYPTASE IN PRESSURE OVERLOAD-INDUCED MAST CELL ACTIVATION, CHYMASE RELEASE AND CARDIAC FIBROSIS

PubMed Central

Li, Jianping; Jubair, Shaiban; Levick, Scott P; Janicki, Joseph S.

2015-01-01

Background Cardiac mast cell (MC) proteases, chymase and tryptase, increase proliferation and collagen synthesis in cultured cardiac fibroblasts. However, the question as to why preventing individually the actions of either protease prevents fibrosis when both are released upon MC activation remains unanswered. Since tryptase has the ability to activate MCs in noncardiac tissues via the protease-activated receptor-2 (PAR-2), there is the possibility that its, in vivo, fibrotic role is due to its ability to induce MC degranulation thereby amplifying the release of chymase. Methods This study sought to delineate the interactions between tryptase and chymase in myocardial remodeling secondary to transverse aortic constriction (TAC) for 5 wks in male Sprague Dawley rats untreated or treated with either the tryptase inhibitor, nafamostat mesilate or MC membrane stabilizing drug, nedocromil (n=6/group). In addition, ventricular slices from 6 rat hearts were incubated with tryptase, tryptase plus nafamostat mesilate or chymostatin for 24 h. Results and Conclusion The results indicate the presence of PAR-2 on MCs and that tryptase inhibition and nedocromil prevented TAC-induced fibrosis and increases in MC density, activation, and chymase release. Tryptase also significantly increased chymase concentration in ventricular tissue culture media, which was prevented by the tryptase inhibitor. Hydroxyproline concentration in culture media was significantly increased with tryptase incubation as compared to the control group and the tryptase group incubated with nafamostat mesilate or chymostatin. We conclude that tryptase contributes to TAC-induced cardiac fibrosis primarily via activation of MCs and the amplified release of chymase. PMID:26722642

Acute inflammation induces segmental, bilateral, supraspinally mediated opioid release in the rat spinal cord, as measured by μ-opioid receptor internalization

PubMed Central

Chen, Wenling; Marvizón, Juan Carlos G.

2009-01-01

The objective of this study was to measure opioid release in the spinal cord during acute and long-term inflammation using μ-opioid receptor (MOR) internalization. In particular, we determined whether opioid release occurs in the segments receiving the noxious signals or in the entire spinal cord, and whether it involves supraspinal signals. Internalization of neurokinin 1 receptors (NK1Rs) was measured to track the intensity of the noxious stimulus. Rats received peptidase inhibitors intrathecally to protect opioids from degradation. Acute inflammation of the hindpaw with formalin induced moderate MOR internalization in the L5 segment bilaterally, whereas NK1R internalization occurred only ipsilaterally. MOR internalization was restricted to the lumbar spinal cord, regardless of whether the peptidase inhibitors were injected in a lumbar or thoracic site. Formalin-induced MOR internalization was substantially reduced by isoflurane anesthesia. It was also markedly reduced by a lidocaine block of the cervical-thoracic spinal cord (which did not affect the evoked NK1R internalization) indicating that spinal opioid release is mediated supraspinally. In the absence of peptidase inhibitors, formalin and hindpaw clamp induced a small amount of MOR internalization, which was significantly higher than in controls. To study spinal opioid release during chronic inflammation, we injected Complete Freund's Adjuvant (CFA) in the hindpaw and peptidase inhibitors intrathecally. Two days later, no MOR or NK1R internalization was detected. Furthermore, CFA inflammation decreased MOR internalization induced by clamping the inflamed hindpaw. These results show that acute inflammation, but not chronic inflammation, induce segmental opioid release in the spinal cord that involves supraspinal signals. PMID:19298846

Acute inflammation induces segmental, bilateral, supraspinally mediated opioid release in the rat spinal cord, as measured by mu-opioid receptor internalization.

PubMed

Chen, W; Marvizón, J C G

2009-06-16

The objective of this study was to measure opioid release in the spinal cord during acute and long-term inflammation using mu-opioid receptor (MOR) internalization. In particular, we determined whether opioid release occurs in the segments receiving the noxious signals or in the entire spinal cord, and whether it involves supraspinal signals. Internalization of neurokinin 1 receptors (NK1Rs) was measured to track the intensity of the noxious stimulus. Rats received peptidase inhibitors intrathecally to protect opioids from degradation. Acute inflammation of the hind paw with formalin induced moderate MOR internalization in the L5 segment bilaterally, whereas NK1R internalization occurred only ipsilaterally. MOR internalization was restricted to the lumbar spinal cord, regardless of whether the peptidase inhibitors were injected in a lumbar or thoracic site. Formalin-induced MOR internalization was substantially reduced by isoflurane anesthesia. It was also markedly reduced by a lidocaine block of the cervical-thoracic spinal cord (which did not affect the evoked NK1R internalization) indicating that spinal opioid release is mediated supraspinally. In the absence of peptidase inhibitors, formalin and hind paw clamp induced a small amount of MOR internalization, which was significantly higher than in controls. To study spinal opioid release during chronic inflammation, we injected complete Freund's adjuvant (CFA) in the hind paw and peptidase inhibitors intrathecally. Two days later, no MOR or NK1R internalization was detected. Furthermore, CFA inflammation decreased MOR internalization induced by clamping the inflamed hind paw. These results show that acute inflammation, but not chronic inflammation, induces segmental opioid release in the spinal cord that involves supraspinal signals.

Azadirachtin-induced apoptosis involves lysosomal membrane permeabilization and cathepsin L release in Spodoptera frugiperda Sf9 cells.

PubMed

Wang, Zheng; Cheng, Xingan; Meng, Qianqian; Wang, Peidan; Shu, Benshui; Hu, Qiongbo; Hu, Meiying; Zhong, Guohua

2015-07-01

Azadirachtin as a kind of botanical insecticide has been widely used in pest control. We previously reported that azadirachtin could induce apoptosis of Spodoptera litura cultured cell line Sl-1, which involves in the up-regulation of P53 protein. However, the detailed mechanism of azadirachtin-induced apoptosis is not clearly understood in insect cultured cells. The aim of the present study was to address the involvement of lysosome and lysosomal protease in azadirachtin-induced apoptosis in Sf9 cells. The result confirmed that azadirachtin indeed inhibited proliferation and induced apoptosis. The lysosomes were divided into different types as time-dependent manner, which suggested that changes of lysosomes were necessarily physiological processes in azadirachtin-induced apoptosis in Sf9 cells. Interestingly, we noticed that azadirachtin could trigger lysosomal membrane permeabilization and cathepsin L releasing to cytosol. Z-FF-FMK (a cathepsin L inhibitor), but not CA-074me (a cathepsin B inhibitor), could effectively hinder the apoptosis induced by azadirachtin in Sf9 cells. Meanwhile, the activity of caspase-3 could also be inactivated by the inhibition of cathepsin L enzymatic activity induced by Z-FF-FMK. Taken together, our findings suggest that azadirachtin could induce apoptosis in Sf9 cells in a lysosomal pathway, and cathepsin L plays a pro-apoptosis role in this process through releasing to cytosol and activating caspase-3. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neonatal methamphetamine-induced corticosterone release in rats is inhibited by adrenal autotransplantation without altering the effect of the drug on hippocampal serotonin

PubMed Central

Grace, Curtis E.; Schaefer, Tori L.; Gudelsky, Gary A.; Williams, Michael T.; Vorhees, Charles V.

2010-01-01

Rat neonatal methamphetamine exposure results in corticosterone release and learning and memory impairments in later life; effects also observed after neonatal stress. Previous attempts to test the role of corticosterone release after methamphetamine using corticosterone inhibitors were unsuccessful and adrenalectomy caused reductions in hippocampal serotonin greater than those caused by methamphetamine alone. Here we tested whether adrenal autotransplantation could be used to attenuate methamphetamine-induced corticosterone release without also altering the effects of the drug on serotonin. Adrenal autotransplantation surgery occurred on postnatal day 9 followed by methamphetamine or saline treatment from postnatal day 11–20 (10 mg/kg/dose x 4/day). Plasma corticosterone and hippocampal serotonin and 5-hydroxyindoleacetic acid were determined 30 min following the first treatment on each day between postnatal days 11–20. Adrenal autotransplantation attenuated neonatal methamphetamine-induced corticosterone release by ~70% initially, ~55% midway through treatment, and ~25% by the end of treatment. Methamphetamine reduced serotonin and 5-hydroxyindoleacetic acid in the hippocampus to the same degree as in sham-surgery rats. The data show that neonatal adrenal autotransplantation is an effective method for partially reducing treatment-induce corticosterone release while providing sufficient corticosterone to sustain normal growth and development. The method should is applicable to other models of developmental stress/corticosterone release. PMID:20153424

Gravity loading induces adenosine triphosphate release and phosphorylation of extracellular signal-regulated kinases in human periodontal ligament cells.

PubMed

Ito, Mai; Arakawa, Toshiya; Okayama, Miki; Shitara, Akiko; Mizoguchi, Itaru; Takuma, Taishin

2014-11-01

The periodontal ligament (PDL) receives mechanical stress (MS) from dental occlusion or orthodontic tooth movement. Mechanical stress is thought to be a trigger for remodeling of the PDL and alveolar bone, although its signaling mechanism is still unclear. So we investigated the effect of MS on adenosine triphosphate (ATP) release and extracellular signal-regulated kinases (ERK) phosphorylation in PDL cells. Mechanical stress was applied to human PDL cells as centrifugation-mediated gravity loading. Apyrase, Ca(2+)-free medium and purinergic receptor agonists and antagonists were utilized to analyze the contribution of purinergic receptors to ERK phosphorylation. Gravity loading and ATP increased ERK phosphorylation by 5 and 2.5 times, respectively. Gravity loading induced ATP release from PDL cells by tenfold. Apyrase and suramin diminished ERK phosphorylation induced by both gravity loading and ATP. Under Ca(2+)-free conditions the phosphorylation by gravity loading was partially decreased, whereas ATP-induced phosphorylation was unaffected. Receptors P2Y4 and P2Y6 were prominently expressed in the PDL cells. Gravity loading induced ATP release and ERK phosphorylation in PDL fibroblasts, and ATP signaling via P2Y receptors was partially involved in this phosphorylation, which in turn would enhance gene expression for the remodeling of PDL tissue during orthodontic tooth movement. © 2013 Wiley Publishing Asia Pty Ltd.

Mechanical perturbation-induced ethylene releases apical dominance in Pharbitis nil by restricting shoot growth

NASA Technical Reports Server (NTRS)

Prasad, T. K.; Cline, M. G.

1985-01-01

Mechanical perturbation (MP, rubbing) or internodes of Pharbitis nil shoots initiates release of lateral buds (LB) from apical dominance within 48 h. Evidence is presented which suggests that MP promotion of LB outgrowth is mediated by ethylene-induced restriction of main shoot growth. Ethylene production in the internodes is stimulated by MP within 2 h. Effects of MP are mimicked by treatments with 1-aminocyclopropane-1-carboxylic acid (ACC) and are negated by the inhibitors of ethylene production or action, aminoethoxy vinylglycine (AVG) and AgNO3. The fact that effects of MP, ACC, and ethylene inhibitors are observed to occur on main shoot growth at least 24 h before they are observed to occur on LB growth suggests a possible cause and effect relationship. MP also causes an increase in internode diameter. MP stimulation of ethylene production appears to be mediated by ACC synthase. The results of this study and our previous studies suggest that apical dominance may be released by any mechanism which induces ethylene restriction of main shoot growth.

D-amphetamine (A)-induced dopamine (DA) release is not strictly dependent on newly-synthesized transmitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, E.; Cubeddu, L.

1986-03-05

A is thought to exert its stimulant effects by releasing DA from a newly synthesized transmitter pool. This hypothesis was evaluated directly by measuring the basal efflux and electrically-evoked release of endogenous DA and dihydroxyphenylacetic acid (DOPAC). In striatal slices from reserpine-treated rabbits A increased DA efflux, reduced DOPAC efflux, and inhibited electrically-evoked /sup 3/H-ACh release in a concentration-dependent manner. These effects could not be mimicked by inhibition of neuronal uptake or MAO, but were blocked by inhibition of DA synthesis or neuronal uptake, and were potentiated by inhibition of MAO. In slices with intact vesicular transmitter stores A inducedmore » DA efflux was 2-fold greater than that seen in slices having no vesicular stores. Inhibition of DA synthesis reduced A-induced DA efflux by 60%, but had little effect on the ability of A to inhibit /sup 3/H-ACh release. A also increased the electrical stimulation-evoked overflow of DA (an effect which was attenuated slightly by synthesis inhibition), and potently inhibited DOPAC overflow. These results suggest that: 1) A facilitates efflux of axoplasmic DA by an accelerated exchange diffusion mechanism. The releasable axoplasmic pool is derived from newly synthesized and vesicular transmitter pools; 2) postsynaptic indices of transmitter release may be misleading; and 3) A increases electrically-evoked DA release possibly by inhibiting neuronal uptake.« less

The gravity-regulated growth of axillary buds is mediated by a mechanism different from decapitation-induced release.

PubMed

Kitazawa, Daisuke; Miyazawa, Yutaka; Fujii, Nobuharu; Hoshino, Atsushi; Iida, Shigeru; Nitasaka, Eiji; Takahashi, Hideyuki

2008-06-01

When the upper part of the main shoot of the Japanese morning glory (Pharbitis nil or Ipomoea nil) is bent down, the axillary bud situated on the uppermost node of the bending region is released from apical dominance and elongates. Here, we demonstrate that this release of axillary buds from apical dominance is gravity regulated. We utilized two agravitropic mutants of morning glory defective in gravisensing cell differentiation, weeping (we) and weeping2 (we2). Bending the main shoots of either we or we2 plants resulted in minimal elongation of their axillary buds. This aberration was genetically linked to the agravitropism phenotype of the mutants, which implied that shoot bending-induced release from apical dominance required gravisensing cells. Previous studies have shown that basipetal translocation of auxin from the apical bud inhibits axillary bud growth, whereas cytokinin promotes axillary bud outgrowth. We therefore compared the roles of auxin and cytokinin in bending- or decapitation-induced axillary bud growth. In the wild-type and we plants, decapitation increased cytokinin levels and reduced auxin response. In contrast, shoot bending did not cause significant changes in either cytokinin level or auxin response, suggesting that the mechanisms underlying gravity- and decapitation-regulated release from apical dominance are distinct and unique.

Effects of some plant lectins on hydrogen peroxide release from macrophages induced with streptococcal preparation OK-432.

PubMed Central

Tomioka, H; Saito, H

1980-01-01

Concanavalin A and phytohemagglutinin were found to cause marked inhibition of H2O2 release from macrophages induced with killed streptococci (preparation OK-432). The inhibitory effect of these two lectins on the H2O2 release from macrophages was observed with spontaneous and wheat germ lectin-triggered H2O2 release. This suggests that the lectins act directly on the macrophage H2O2-releasing function, per se, but not on the wheat germ lectin-H2O2 release-enhancing process. Concanavalin A exhibited its inhibitory action on macrophage H2O2 release by specific binding to D-mannopyranoside receptor sites on the macrophage cell surface. Galactose-binding lectins, peanut agglutinin, and soybean agglutinin failed to inhibit, but, on the other hand, slightly enhanced macrophage H2O2 release. The effect of these five lectins on the phagocytosis of latex particles by macrophages was tested. Wheat germ lectin, concanavalin A, and phytohemagglutinin significantly depressed the macrophage phagocytosis, whereas peanut agglutinin and soybean agglutinin failed to show any inhibitory action. PMID:7399666

Corticotropin-releasing hormone and dopamine release in healthy individuals.

PubMed

Payer, Doris; Williams, Belinda; Mansouri, Esmaeil; Stevanovski, Suzanna; Nakajima, Shinichiro; Le Foll, Bernard; Kish, Stephen; Houle, Sylvain; Mizrahi, Romina; George, Susan R; George, Tony P; Boileau, Isabelle

2017-02-01

Corticotropin-releasing hormone (CRH) is a key component of the neuroendocrine response to stress. In animal models, CRH has been shown to modulate dopamine release, and this interaction is believed to contribute to stress-induced relapse in neuropsychiatric disorders. Here we investigated whether CRH administration induces dopamine release in humans, using positron emission tomography (PET). Eight healthy volunteers (5 female, 22-48 years old) completed two PET scans with the dopamine D 2/3 receptor radioligand [ 11 C]-(+)-PHNO: once after saline injection, and once after injection of corticorelin (synthetic human CRH). We also assessed subjective reports and measured plasma levels of endocrine hormones (adrenocorticotropic hormone and cortisol). Relative to saline, corticorelin administration decreased binding of the D 2/3 PET probe [ 11 C]-(+)-PHNO, suggesting dopamine release. Endocrine stress markers were also elevated, in line with activation of the hypothalamic-pituitary-adrenal axis, but we detected no changes in subjective ratings. Preliminary results from this proof-of-concept study suggests that CRH challenge in combination with [ 11 C]-(+)-PHNO PET may serve as an assay of dopamine release, presenting a potential platform for evaluating CRH/dopamine interactions in neuropsychiatric disorders and CRH antagonists as potential treatment avenues. Copyright © 2016 Elsevier Ltd. All rights reserved.

Calcium-Induced calcium release during action potential firing in developing inner hair cells.

PubMed

Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J

2015-03-10

In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

Inhibition by prostaglandin E(2) of anaphylatoxin C5a- but not zymosan-induced prostanoid release from rat Kupffer cells.

PubMed

Pestel, Sabine; Jungermann, Kurt; Götze, Otto; Schieferdecker, Henrike L

2002-04-01

The proinflammatory anaphylatoxin C5a induces the release of prostanoids, ie, prostaglandins (PG) and thromboxane (TX), from the resident liver macrophages (Kupffer cells [KC]). Because KC themselves express prostanoid receptors, prostanoids--besides having paracrine functions--might regulate their own release in an autocrine loop. So far, such a possible feedback regulation has not been investigated systematically, probably because of methodological difficulties to measure newly synthesized prostanoids in the presence of added prostanoids. Here, after prelabeling of phospholipids with [(14)C]arachidonate, cellularly formed [(14)C]prostanoids were determined in the presence of added unlabelled prostanoids by thin layer chromatography. In cultured KC, recombinant rat C5a (rrC5a) rapidly increased PGD(2), PGE(2), and TXA(2) release, which was strongly reduced by PGE(2), but neither by PGD(2) nor by the TXA(2) analog U46619. The inhibitory effect of PGE(2) was mimicked by cAMP, indicating that the G(s)-coupled PGE(2) receptors type 2 or 4 were involved. Zymosan also enhanced prostanoid release from KC, but with slightly slower kinetics; this action was neither inhibited by PGE(2) nor by cAMP. Also in perfused rat livers, rrC5a enhanced prostanoid release from KC as shown by prostanoid overflow and thereby indirectly increased glucose output from hepatocytes. Again, PGE(2), but not PGD(2), inhibited rrC5a-elicited prostanoid overflow. This resulted in a complete inhibition of rrC5a-induced, prostanoid-mediated glucose output. Thus, PGE(2) can inhibit specifically the C5a-induced prostanoid release from KC via a feedback mechanism and thereby limit prostanoid-mediated hepatocellular defense reactions, eg, glucose release.

Coincident postsynaptic activity gates presynaptic dopamine release to induce plasticity in Drosophila mushroom bodies

PubMed Central

Ueno, Kohei; Suzuki, Ema; Naganos, Shintaro; Ofusa, Kyoko; Horiuchi, Junjiro; Saitoe, Minoru

2017-01-01

Simultaneous stimulation of the antennal lobes (ALs) and the ascending fibers of the ventral nerve cord (AFV), two sensory inputs to the mushroom bodies (MBs), induces long-term enhancement (LTE) of subsequent AL-evoked MB responses. LTE induction requires activation of at least three signaling pathways to the MBs, mediated by nicotinic acetylcholine receptors (nAChRs), NMDA receptors (NRs), and D1 dopamine receptors (D1Rs). Here, we demonstrate that inputs from the AL are transmitted to the MBs through nAChRs, and inputs from the AFV are transmitted by NRs. Dopamine signaling occurs downstream of both nAChR and NR activation, and requires simultaneous stimulation of both pathways. Dopamine release requires the activity of the rutabaga adenylyl cyclase in postsynaptic MB neurons, and release is restricted to MB neurons that receive coincident stimulation. Our results indicate that postsynaptic activity can gate presynaptic dopamine release to regulate plasticity. DOI: http://dx.doi.org/10.7554/eLife.21076.001 PMID:28117664

Nicotine-induced Conditional Place Preference is Affected by Head Injury: Correlation with Dopamine Release in the Nucleus Accumbens Shell.

PubMed

Yuan-Hao, Chen; Kuo, Tung-Tai; Huang, Eagle Yi-Kung; Hoffer, Barry J; Kao, Jen-Hsin; Chou, Yu-Ching; Chiang, Yung-Hsiao; Miller, Jonathan

2018-06-14

Traumatic brain injury (TBI) is known to impact dopamine-mediated reward pathways, but the underlying mechanisms have not been fully established. Nicotine-induced conditional place preference (CPP) was used to study rats exposed to a 6-psi fluid percussion injury (FPI) with and without prior exposure to nicotine. Preference was quantified as a score defined as (C1-C2) / (C1+C2), where C1 is time in the nicotine-paired compartment and C2 is time in the saline-paired compartment. Subsequent fast-scan cyclic voltammetry (FSCV) was used to analyze the impact of nicotine infusion on dopamine release in the shell portion of the nucleus accumbens (NAc). To further determine the influence of brain injury on nicotine withdrawal, nicotine infusion was administered to the rats after FPI. The effects of FPI on CPP after prior exposure to nicotine and abstinence or withdrawal from nicotine were also assessed. After TBI, dopamine release was reduced in the NAc shell, and nicotine-induced CPP preference was significantly impaired. Preference scores of control, sham-injured, and FPI groups were 0.1627 ± 0.04204, 0.1515 ± 0.03806, and -0.001300 ± 0.04286, respectively. Nicotine-induced CPP was also seen in animals after nicotine pre-treatment, with a CPP score of 0.07805 ± 0.02838. Nicotine pre-exposure substantially increased tonic dopamine release in sham-injured animals, but it did not change phasic release; nicotine exposure after FPI enhanced phasic release, though not to the same levels seen in sham-injured rats. Conditioned preference was related not only to phasic dopamine release (r= 0.8110) but also to the difference between tonic and phasic dopamine levels (r= 0.9521). TBI suppresses dopamine release from the shell portion of the NAc, which in turn significantly alters reward-seeking behavior. These results have important implications for tobacco and drug use after TBI.

The 5-HT(1A) receptor agonist, 8-OH-DPAT, attenuates stress-induced anorexia in conjunction with the suppression of hypothalamic serotonin release in rats.

PubMed

Shimizu, N; Hori, T; Ogino, C; Kawanishi, T; Hayashi, Y

2000-12-22

The effect of the selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on stress-induced anorexia and serotonin (5-HT) release in the rat hypothalamus was studied with brain microdialysis. Subcutaneous injection of 8-OH-DPAT (1 mg/kg) significantly attenuated the immobilization-induced anorexia for 3 h, but had no effect during the following 9 h. Injection of 8-OH-DPAT itself had no effect on basal release of 5-HT, while it significantly blocked the immobilization-induced 5-HT release in the lateral hypothalamus. The results suggest that 8-OH-DPAT attenuated the stress-induced anorexia through the activation of 5-HT(1A) autoreceptors in dorsal raphe nucleus.

Platelet-Released Growth Factors Induce Differentiation of Primary Keratinocytes

PubMed Central

Tohidnezhad, Mersedeh; Lammel, Justus; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Jahr, Holger; Cremer, Jochen; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

2017-01-01

Autologous thrombocyte concentrate lysates, for example, platelet-released growth factors, (PRGFs) or their clinically related formulations (e.g., Vivostat PRF®) came recently into the physicians' focus as they revealed promising effects in regenerative and reparative medicine such as the support of healing of chronic wounds. To elucidate the underlying mechanisms, we analyzed the influence of PRGF and Vivostat PRF on human keratinocyte differentiation in vitro and on epidermal differentiation status of skin wounds in vivo. Therefore, we investigated the expression of early (keratin 1 and keratin 10) and late (transglutaminase-1 and involucrin) differentiation markers. PRGF treatment of primary human keratinocytes decreased keratin 1 and keratin 10 gene expression but induced involucrin and transglutaminase-1 gene expression in an epidermal growth factor receptor- (EGFR-) dependent manner. In concordance with these results, microscopic analyses revealed that PRGF-treated human keratinocytes displayed morphological features typical of keratinocytes undergoing terminal differentiation. In vivo treatment of artificial human wounds with Vivostat PRF revealed a significant induction of involucrin and transglutaminase-1 gene expression. Together, our results indicate that PRGF and Vivostat PRF induce terminal differentiation of primary human keratinocytes. This potential mechanism may contribute to the observed beneficial effects in the treatment of hard-to-heal wounds with autologous thrombocyte concentrate lysates in vivo. PMID:28808357

Protective effect of Growth Hormone-Releasing Hormone agonist in bacterial toxin-induced pulmonary barrier dysfunction.

PubMed

Czikora, Istvan; Sridhar, Supriya; Gorshkov, Boris; Alieva, Irina B; Kasa, Anita; Gonzales, Joyce; Potapenko, Olena; Umapathy, Nagavedi S; Pillich, Helena; Rick, Ferenc G; Block, Norman L; Verin, Alexander D; Chakraborty, Trinad; Matthay, Michael A; Schally, Andrew V; Lucas, Rudolf

2014-01-01

Antibiotic treatment of patients infected with G(-) or G(+) bacteria promotes release of the toxins lipopolysaccharide (LPS) and pneumolysin (PLY) in their lungs. Growth Hormone-releasing Hormone (GHRH) agonist JI-34 protects human lung microvascular endothelial cells (HL-MVEC), expressing splice variant 1 (SV-1) of the receptor, from PLY-induced barrier dysfunction. We investigated whether JI-34 also blunts LPS-induced hyperpermeability. Since GHRH receptor (GHRH-R) signaling can potentially stimulate both cAMP-dependent barrier-protective pathways as well as barrier-disruptive protein kinase C pathways, we studied their interaction in GHRH agonist-treated HL-MVEC, in the presence of PLY, by means of siRNA-mediated protein kinase A (PKA) depletion. Barrier function measurements were done in HL-MVEC monolayers using Electrical Cell substrate Impedance Sensing (ECIS) and VE-cadherin expression by Western blotting. Capillary leak was assessed by Evans Blue dye (EBD) incorporation. Cytokine generation in broncho-alveolar lavage fluid (BALF) was measured by multiplex analysis. PKA and PKC-α activity were assessed by Western blotting. GHRH agonist JI-34 significantly blunts LPS-induced barrier dysfunction, at least in part by preserving VE-cadherin expression, while not affecting inflammation. In addition to activating PKA, GHRH agonist also increases PKC-α activity in PLY-treated HL-MVEC. Treatment with PLY significantly decreases resistance in control siRNA-treated HL-MVEC, but does so even more in PKA-depleted monolayers. Pretreatment with GHRH agonist blunts PLY-induced permeability in control siRNA-treated HL-MVEC, but fails to improve barrier function in PKA-depleted PLY-treated monolayers. GHRH signaling in HL-MVEC protects from both LPS and PLY-mediated endothelial barrier dysfunction and concurrently induces a barrier-protective PKA-mediated and a barrier-disruptive PKC-α-induced pathway in the presence of PLY, the former of which dominates the latter.

Milk bioactive peptides and beta-casomorphins induce mucus release in rat jejunum.

PubMed

Trompette, Aurélien; Claustre, Jean; Caillon, Fabienne; Jourdan, Gérard; Chayvialle, Jean Alain; Plaisancié, Pascale

2003-11-01

Intestinal mucus is critically involved in the protection of the mucosa. An enzymatic casein hydrolysate and beta-casomorphin-7, a mu-opioid peptide generated in the intestine during bovine casein digestion, markedly induce mucus discharge. Because shorter mu-opioid peptides have been described, the effects of the opioid peptides in casein, beta-casomorphin-7, -6, -4, -4NH2 and -3, and of opioid neuropeptides met-enkephalin, dynorphin A and (D-Ala2,N-Me-Phe4,glycinol5)enkephalin (DAMGO) on intestinal mucus secretion were investigated. The experiments were conducted with isolated perfused rat jejunum. Mucus secretion under the influence of beta-casomorphins and opioid neuropeptides administered intraluminally or intra-arterially was evaluated using an ELISA for rat intestinal mucus. Luminal administration of beta-casomorphin-7 (1.2 x 10(-4) mol/L) provoked a mucus discharge (500% of controls) that was inhibited by naloxone, a specific opiate receptor antagonist. Luminal beta-casomorphin-6, -4 and -4NH2 did not modify basal mucus secretion, whereas intra-arterial administration of beta-casomorphin-4 (1.2 x 10(-6) mol/L) induced a mucus discharge. In contrast, intra-arterial administration of the nonopioid peptide beta-casomorphin-3 did not release mucus. Among the opioid neuropeptides, intra-arterial infusion of Met-enkephalin or dynorphin-A did not provoke mucus secretion. In contrast, beta-endorphin (1.2 x 10(-8) to 1.2 x 10(-6) mol/L) induced a dose-dependent release of mucus (maximal response at 500% of controls). DAMGO (1.2 x 10(-6) mol/L), a mu-receptor agonist, also evoked a potent mucus discharge. Our findings suggest that mu-opioid neuropeptides, as well as beta-casomorphins after absorption, modulate intestinal mucus discharge. Milk opioid-derived peptides may thus be involved in defense against noxious agents and could have dietary and health applications.

Modulation of basal and stress-induced amygdaloid substance P release by the potent and selective NK1 receptor antagonist L-822429.

PubMed

Singewald, Nicolas; Chicchi, Gary G; Thurner, Clemens C; Tsao, Kwei-Lan; Spetea, Mariana; Schmidhammer, Helmut; Sreepathi, Hari Kishore; Ferraguti, Francesco; Singewald, Georg M; Ebner, Karl

2008-09-01

It has been shown that anxiety and stress responses are modulated by substance P (SP) released within the amygdala. However, there is an important gap in our knowledge concerning the mechanisms regulating extracellular SP in this brain region. To study a possible self-regulating role of SP, we used a selective neurokinin-1 (NK1) receptor antagonist to investigate whether blockade of NK1 receptors results in altered basal and/or stress-evoked SP release in the medial amygdala (MeA), a critical brain area for a functional involvement of SP transmission in enhanced anxiety responses induced by stressor exposure. In vitro binding and functional receptor assays revealed that L-822429 represents a potent and selective rat NK1 receptor antagonist. Intra-amygdaloid administration of L-822429 via inverse microdialysis enhanced basal, but attenuated swim stress-induced SP release, while the low-affinity enantiomer of L-822429 had no effect. Using light and electron microscopy, synaptic contacts between SP-containing fibres and dendrites expressing NK1 receptors was demonstrated in the medial amygdala. Our findings suggest self-regulatory capacity of SP-mediated neurotransmission that differs in the effect on basal and stress-induced release of SP. Under basal conditions endogenous SP can serve as a signal that tonically inhibits its own release via a NK1 receptor-mediated negative feedback action, while under stress conditions SP release is further facilitated by activation of NK1 receptors, likely leading to high local levels of SP and activation of receptors to which SP binds with lower affinity.

Sound Waves Induce Neural Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells via Ryanodine Receptor-Induced Calcium Release and Pyk2 Activation.

PubMed

Choi, Yura; Park, Jeong-Eun; Jeong, Jong Seob; Park, Jung-Keug; Kim, Jongpil; Jeon, Songhee

2016-10-01

Mesenchymal stem cells (MSCs) have shown considerable promise as an adaptable cell source for use in tissue engineering and other therapeutic applications. The aims of this study were to develop methods to test the hypothesis that human MSCs could be differentiated using sound wave stimulation alone and to find the underlying mechanism. Human bone marrow (hBM)-MSCs were stimulated with sound waves (1 kHz, 81 dB) for 7 days and the expression of neural markers were analyzed. Sound waves induced neural differentiation of hBM-MSC at 1 kHz and 81 dB but not at 1 kHz and 100 dB. To determine the signaling pathways involved in the neural differentiation of hBM-MSCs by sound wave stimulation, we examined the Pyk2 and CREB phosphorylation. Sound wave induced an increase in the phosphorylation of Pyk2 and CREB at 45 min and 90 min, respectively, in hBM-MSCs. To find out the upstream activator of Pyk2, we examined the intracellular calcium source that was released by sound wave stimulation. When we used ryanodine as a ryanodine receptor antagonist, sound wave-induced calcium release was suppressed. Moreover, pre-treatment with a Pyk2 inhibitor, PF431396, prevented the phosphorylation of Pyk2 and suppressed sound wave-induced neural differentiation in hBM-MSCs. These results suggest that specific sound wave stimulation could be used as a neural differentiation inducer of hBM-MSCs.

Single and combined effects of carbamazepine and vinpocetine on depolarization-induced changes in Na+, Ca2+ and glutamate release in hippocampal isolated nerve endings.

PubMed

Sitges, María; Chiu, Luz María; Nekrassov, Vladimir

2006-07-01

The single and combined effects of carbamazepine and vinpocetine on the release of the excitatory amino acid neurotransmitter glutamate, on the rise in internal Na+ (Na(i), as determined with SBFI), and on the rise in internal Ca2+ (Ca(i), as determined with fura-2) induced by an increased permeability of presynaptic Na+ channels, with veratridine, or by an increased permeability of presynaptic Ca2+ channels with high K+, were investigated in isolated hippocampal nerve endings. The present study shows that carbamazepine and vinpocetine, both inhibit dose dependently the release of preloaded [3H]Glu induced by veratridine. However, carbamazepine is two orders of magnitude less potent than vinpocetine. The calculated IC(50)'s for carbamazepine and vinpocetine to inhibit veratridine-induced [3H]Glu release are 200 and 2 microM, respectively. Consistently 150 microM carbamazepine and 1.5 microM vinpocetine reduce the veratridine-induced rise in Na(i) in a similar extent. The single effects of carbamazepine and of vinpocetine on the presynaptic Na+ channel mediated responses, namely the rise in Na(i) and the release of Glu induced by veratridine, are additive. Responses that depend on the entrance of external Ca2+ via presynaptic Ca2+ channels, such as the release of [3H]Glu and the rise in Ca(i) induced by high K+, are insensitive to 300 microM carbamazepine and slightly reduced by 5 microM vinpocetine. It is concluded that the additive effects of carbamazepine, which is one of the most common antiepileptic drugs, and vinpocetine that besides its known neuroprotective action and antiepileptic potential is a memory enhancer, may perhaps be advantageous in the treatment of epileptic patients.

Drug-induced GABA transporter currents enhance GABA release to induce opioid withdrawal behaviors.

PubMed

Bagley, Elena E; Hacker, Jennifer; Chefer, Vladimir I; Mallet, Christophe; McNally, Gavan P; Chieng, Billy C H; Perroud, Julie; Shippenberg, Toni S; Christie, MacDonald J

2011-10-30

Neurotransmitter transporters can affect neuronal excitability indirectly via modulation of neurotransmitter concentrations or directly via transporter currents. A physiological or pathophysiological role for transporter currents has not been described. We found that GABA transporter 1 (GAT-1) cation currents directly increased GABAergic neuronal excitability and synaptic GABA release in the periaqueductal gray (PAG) during opioid withdrawal in rodents. In contrast, GAT-1 did not indirectly alter GABA receptor responses via modulation of extracellular GABA concentrations. Notably, we found that GAT-1-induced increases in GABAergic activity contributed to many PAG-mediated signs of opioid withdrawal. Together, these data support the hypothesis that GAT-1 activity directly produces opioid withdrawal signs through direct hyperexcitation of GABAergic PAG neurons and nerve terminals, which presumably enhances GABAergic inhibition of PAG output neurons. These data provide, to the best of our knowledge, the first evidence that dysregulation of a neurotransmitter transporter current is important for the maladaptive plasticity that underlies opiate withdrawal.

AT1 receptors mediate angiotensin II-induced release of nitric oxide in afferent arterioles.

PubMed

Patzak, Andreas; Lai, En Y; Mrowka, Ralf; Steege, Andreas; Persson, Pontus B; Persson, A Erik G

2004-11-01

Recent studies have indicated that angiotensin II (Ang II) possibly activates the nitric oxide (NO) system. We investigated the role of AT receptor subtypes (AT-R) in mediating the Ang II-induced NO release in afferent arterioles (Af) of mice. Isolated Af of mice were perfused, and the isotonic contraction measured. Further, NO release was determined using DAF-FM, a fluorescence indicator for NO. Moreover, we qualitatively assessed the expression of AT-R at the mRNA level using reverse transcription-polymerase chain reaction (RT-PCR). Ang II reduced luminal diameters dose dependently (67.3 +/- 6.3% at 10(-6) mol/L). Inhibition of AT2-R with PD123.319 did not change the Ang II contractile response. AT1-R blockade with ZD7155 inhibited contraction. Stimulation of AT2-R during AT1-R inhibition with ZD7155, and preconstriction with norepinephrine (NE) had no influence on the diameter. Drug application via the perfusion pipette changed flow and pressure, and enhanced NO fluorescence by DeltaF = 4.0 +/- 0.4% (N= 14, background). Luminal application of Ang II (10(-7) mol/L) increased the NO fluorescence by DeltaF = 9.9 +/- 1.2% (N= 8). AT1-R blockade blunted the increase to background levels (DeltaF to 4.0 +/- 0.3%, N= 6, P < 0.05), but AT2-R blockade did not (8.1 +/- 0.9%, N= 9). L-NAME nearly abolished the Ang II effect on the NO fluorescence (DeltaF = 1.6 +/- 0.5% (N= 8). NE did not increase NO release beyond the background levels. RT-PCR showed expression of both AT1-R and AT2-R. The results indicate an Ang II-induced NO release in Af of mice, which is mediated by AT1-R. Thus, Ang II balances its own constrictor action in Af. This control mechanism is very important in view of high renin and angiotensin II concentration in the juxtaglomerular apparatus.

Effects of habitual exercise on the eHsp72-induced release of inflammatory cytokines by macrophages from obese Zucker rats.

PubMed

Garcia, J J; Martin-Cordero, L; Hinchado, M D; Bote, M E; Ortega, E

2013-06-01

Regular exercise is a good non-pharmacological treatment of metabolic syndrome in that it improves obesity, diabetes, and inflammation. The 72 kDa extracellular heat shock protein (eHsp72) is released during exercise, thus stimulating the inflammatory responses. The aim of the present work was to evaluate the effect of regular exercise on the eHsp72-induced release of IL-1β, IL-6, and TNFα by macrophages from genetically obese Zucker rats (fa/fa) (ObZ), using lean Zucker (LZ) rats (Fa/fa) to provide reference values. ObZ presented a higher plasma concentration of eHsp72 than LZ, and exercise increased that concentration. In response to eHsp72, the macrophages from ObZ released less IL-1β and TNFα, but more IL-6, than macrophages from LZ. While eHsp72 stimulated the release of IL-1β, TNFα, and IL-6 in the macrophages from healthy LZ (with respect to the constitutive release), it inhibited the release of IL-1β and IL-6 in macrophages from ObZ. The habitual exercise improved the release of inflammatory cytokines by macrophages from ObZ in response to eHsp72 (it increased IL-1β and TNFα, and decreased IL-6), tending to values closer to those determined in healthy LZ. A deregulated macrophage inflammatory and stress response induced by eHsp72 underlies MS, and this is improved by habitual exercise. © Georg Thieme Verlag KG Stuttgart · New York.

AhV_aPA-induced vasoconstriction involves the IP₃Rs-mediated Ca²⁺ releasing.

PubMed

Zeng, Fuxing; Zou, Zhisong; Niu, Liwen; Li, Xu; Teng, Maikun

2013-08-01

AhV_aPA, the acidic PLA₂ purified from Agkistrodon halys pallas venom, was previously reported to possess a strong enzymatic activity and can remarkably induce a further contractile response on the 60 mM K⁺-induced contraction with an EC₅₀ in 369 nM on mouse thoracic aorta rings. In the present study, we found that the p-bromo-phenacyl-bromide (pBPB), which can completely inhibit the enzymatic activity of AhV_aPA, did not significantly reduce the contractile response on vessel rings induced by AhV_aPA, indicating that the vasoconstrictor effects of AhV_aPA are independent of the enzymatic activity. The inhibitor experiments showed that the contractile response induced by AhV_aPA is mainly attributed to the Ca²⁺ releasing from Ca²⁺ store, especially sarcoplasmic reticulum (SR). Detailed studies showed that the Ca²⁺ release from SR is related to the activation of inositol trisphosphate receptors (IP₃Rs) rather than ryanodine receptors (RyRs). Furthermore, the vasoconstrictor effect could be strongly reduced by pre-incubation with heparin, indicating that the basic amino acid residues on the surface of AhV_aPA may be involved in the interaction between AhV_aPA and the molecular receptors. These findings offer new insights into the functions of snake PLA₂ and provide a novel pathogenesis of A. halys pallas venom. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanisms of HSP72 release.

PubMed

Asea, Alexzander

2007-04-01

Currently two mechanisms are recognized by which heat shock proteins (HSP) are released from cells; a passive release mechanism, including necrotic cell death, severe blunt trauma, surgery and following infection with lytic viruses, and an active release mechanism which involves the non classical protein release pathway. HSPs are released both as free HSP and within exosomes. This review covers recent findings on the mechanism by which stress induces the release of HSP72 into the circulation and the biological significance of circulating HSP72 to host defense against disease.

Voltage-dependent Ca2+ release from the SR of feline ventricular myocytes is explained by Ca2+-induced Ca2+ release.

PubMed

Piacentino, V; Dipla, K; Gaughan, J P; Houser, S R

2000-03-15

1. Direct voltage-gated (voltage-dependent Ca2+ release, VDCR) and Ca2+ influx-gated (Ca2+-induced Ca2+ release, CICR) sarcoplasmic reticulum (SR) Ca2+ release were studied in feline ventricular myocytes. The voltage-contraction relationship predicted by the VDCR hypothesis is sigmoidal with large contractions at potentials near the Ca2+ equilibrium potential (ECa). The relationship predicted by the CICR hypothesis is bell-shaped with no contraction at ECa. 2. The voltage dependence of contraction was measured in ventricular myocytes at physiological temperature (37 C), resting membrane potential and physiological [K+]. Experiments were performed with cyclic adenosine 3',5'-monophosphate (cAMP) in the pipette or in the presence of the beta-adrenergic agonist isoproterenol (isoprenaline; ISO). 3. The voltage-contraction relationship was bell-shaped in Na+-free solutions (to eliminate the Na+ current and Na+-Ca2+ exchange, NCX) but the relationship was broader than the L-type Ca2+ current (ICa,L)-voltage relationship. 4. Contractions induced with voltage steps from normal resting potentials to -40 mV are thought to represent VDCR rather than CICR. We found that cAMP and ISO shifted the voltage dependence of ICa,L activation to more negative potentials so that ICa,L was always present with steps to -40 mV. ICa,L at -40 mV inactivated when the holding potential was decreased (VŁ = -57.8 +/- 0.49 mV). 5. ISO increased inward current, SR Ca2+ load and contraction in physiological [Na+] and a broad bell-shaped voltage-contraction relationship was observed. Inhibition of reverse-mode NCX, decreasing ICa,L and decreasing SR Ca2+ loading all decreased contractions at strongly positive potentials near ECa. 6. The voltage-contraction relationship in 200 microM cadmium (Cd2+) was bell-shaped, supporting a role of ICa,L rather than VDCR. 7. All results could be accounted for by the CICR hypothesis, and many results exclude the VDCR hypothesis.

Voltage-dependent Ca2+ release from the SR of feline ventricular myocytes is explained by Ca2+-induced Ca2+ release

PubMed Central

Piacentino, Valentino; Dipla, Konstantina; Gaughan, John P; Houser, Steven R

2000-01-01

Direct voltage-gated (voltage-dependent Ca2+ release, VDCR) and Ca2+ influx-gated (Ca2+-induced Ca2+ release, CICR) sarcoplasmic reticulum (SR) Ca2+ release were studied in feline ventricular myocytes. The voltage-contraction relationship predicted by the VDCR hypothesis is sigmoidal with large contractions at potentials near the Ca2+ equilibrium potential (ECa). The relationship predicted by the CICR hypothesis is bell-shaped with no contraction at ECa. The voltage dependence of contraction was measured in ventricular myocytes at physiological temperature (37 °C), resting membrane potential and physiological [K+]. Experiments were performed with cyclic adenosine 3′,5′-monophosphate (cAMP) in the pipette or in the presence of the β-adrenergic agonist isoproterenol (isoprenaline; ISO). The voltage-contraction relationship was bell-shaped in Na+-free solutions (to eliminate the Na+ current and Na+-Ca2+ exchange, NCX) but the relationship was broader than the L-type Ca2+ current (ICa,L)-voltage relationship. Contractions induced with voltage steps from normal resting potentials to -40 mV are thought to represent VDCR rather than CICR. We found that cAMP and ISO shifted the voltage dependence of ICa,L activation to more negative potentials so that ICa,L was always present with steps to -40 mV. ICa,L at -40 mV inactivated when the holding potential was decreased (V½ =−57·8 ± 0·49 mV). ISO increased inward current, SR Ca2+ load and contraction in physiological [Na+] and a broad bell-shaped voltage-contraction relationship was observed. Inhibition of reverse-mode NCX, decreasing ICa,L and decreasing SR Ca2+ loading all decreased contractions at strongly positive potentials near ECa. The voltage-contraction relationship in 200 μM cadmium (Cd2+) was bell-shaped, supporting a role of ICa,L rather than VDCR. All results could be accounted for by the CICR hypothesis, and many results exclude the VDCR hypothesis. PMID:10718736

Regulation of zinc homeostasis by inducible NO synthase-derived NO: nuclear metallothionein translocation and intranuclear Zn2+ release.

PubMed

Spahl, Daniela U; Berendji-Grün, Denise; Suschek, Christoph V; Kolb-Bachofen, Victoria; Kröncke, Klaus-D

2003-11-25

Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein (MT) and probably other proteins that complex Zn2+ via cysteine thiols. We show here that, in cytokine-activated murine aortic endothelial cells, NO derived from the inducible NO synthase (iNOS) induces a transient nuclear release of Zn2+. This nuclear Zn2+ release depends on the presence of MT as shown by the lack of this effect in activated endothelial cells from MT-deficient mice and temporally correlates with nuclear MT translocation. Data also show that NO is an essential but not sufficient signal for MT-mediated Zn2+ trafficking from the cytoplasm into the nucleus. In addition, we found that, endogenously via iNOS, synthesized NO increases the constitutive mRNA expression of both MT-1 and MT-2 genes and that nitrosative stress exogenously applied via an NO donor increases constitutive MT mRNA expression via intracellular Zn2+ release. In conclusion, we here provide evidence for a signaling mechanism based on iNOS-derived NO through the regulation of intracellular Zn2+ trafficking and homeostasis.

Regulation of zinc homeostasis by inducible NO synthase-derived NO: Nuclear metallothionein translocation and intranuclear Zn2+ release

PubMed Central

Spahl, Daniela U.; Berendji-Grün, Denise; Suschek, Christoph V.; Kolb-Bachofen, Victoria; Kröncke, Klaus-D.

2003-01-01

Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein (MT) and probably other proteins that complex Zn2+ via cysteine thiols. We show here that, in cytokine-activated murine aortic endothelial cells, NO derived from the inducible NO synthase (iNOS) induces a transient nuclear release of Zn2+. This nuclear Zn2+ release depends on the presence of MT as shown by the lack of this effect in activated endothelial cells from MT-deficient mice and temporally correlates with nuclear MT translocation. Data also show that NO is an essential but not sufficient signal for MT-mediated Zn2+ trafficking from the cytoplasm into the nucleus. In addition, we found that, endogenously via iNOS, synthesized NO increases the constitutive mRNA expression of both MT-1 and MT-2 genes and that nitrosative stress exogenously applied via an NO donor increases constitutive MT mRNA expression via intracellular Zn2+ release. In conclusion, we here provide evidence for a signaling mechanism based on iNOS-derived NO through the regulation of intracellular Zn2+ trafficking and homeostasis. PMID:14617770

β2 integrin mediates hantavirus-induced release of neutrophil extracellular traps

PubMed Central

Raftery, Martin J.; Lalwani, Pritesh; Krautkrӓmer, Ellen; Peters, Thorsten; Scharffetter-Kochanek, Karin; Krüger, Renate; Hofmann, Jörg; Seeger, Karl; Krüger, Detlev H.

2014-01-01

Rodent-borne hantaviruses are emerging human pathogens that cause severe human disease. The underlying mechanisms are not well understood, as hantaviruses replicate in endothelial and epithelial cells without causing any cytopathic effect. We demonstrate that hantaviruses strongly stimulated neutrophils to release neutrophil extracellular traps (NETs). Hantavirus infection induced high systemic levels of circulating NETs in patients and this systemic NET overflow was accompanied by production of autoantibodies to nuclear antigens. Analysis of the responsible mechanism using neutrophils from β2 null mice identified β2 integrin receptors as a master switch for NET induction. Further experiments suggested that β2 integrin receptors such as complement receptor 3 (CR3) and 4 (CR4) may act as novel hantavirus entry receptors. Using adenoviruses, we confirmed that viral interaction with β2 integrin induced strong NET formation. Collectively, β2 integrin–mediated systemic NET overflow is a novel viral mechanism of immunopathology that may be responsible for characteristic aspects of hantavirus-associated disease such as kidney and lung damage. PMID:24889201

Histamine-releasing factor/translationally controlled tumor protein (HRF/TCTP)-induced histamine release is enhanced with SHIP-1 knockdown in cultured human mast cell and basophil models

PubMed Central

Langdon, Jacqueline M.; Schroeder, John T.; Vonakis, Becky M.; Bieneman, Anja P.; Chichester, Kristin; MacDonald, Susan M.

2008-01-01

Previously, we demonstrated a negative correlation between histamine release to histamine-releasing factor/translationally controlled tumor protein (HRF/TCTP) and protein levels of SHIP-1 in human basophils. The present study was conducted to investigate whether suppressing SHIP-1 using small interfering (si)RNA technology would alter the releasability of culture-derived mast cells and basophils, as determined by HRF/TCTP histamine release. Frozen CD34+ cells were obtained from the Fred Hutchinson Cancer Research Center (Seattle, WA, USA). Cells were grown in StemPro-34 medium containing cytokines: mast cells with IL-6 and stem cell factor (100 ng/ml each) for 6–8 weeks and basophils with IL-3 (6.7 ng/ml) for 2–3 weeks. siRNA transfections were performed during Week 6 for mast cells and Week 2 for basophils with siRNA for SHIP-1 or a negative control siRNA. Changes in SHIP-1 expression were determined by Western blot. The functional knockdown was measured by HRF/TCTP-induced histamine release. siRNA knockdown of SHIP-1 in mast cells ranged from 31% to 82%, mean 65 ± 12%, compared with control (n=4). Histamine release to HRF/TCTP was increased only slightly in two experiments. SHIP-1 knockdown in basophils ranged from 34% to 69%, mean 51.8 ± 7% (n=4). Histamine release to HRF/TCTP in these basophils was dependent on the amount of SHIP knockdown. Mast cells and basophils derived from CD34+ precursor cells represent suitable models for transfection studies. Reducing SHIP-1 protein in cultured mast cells and in cultured basophils increases releasability of the cells. PMID:18625911

Putting out the fire: what terminates calcium-induced calcium release in cardiac muscle?

PubMed

Stern, Michael D; Cheng, Heping

2004-06-01

The majority of contractile calcium in cardiac muscle is released from stores in the sarcoplasmic reticulum (SR), by a process of calcium-induced calcium release (CICR) through ryanodine receptors. Because CICR is intrinsically self-reinforcing, the stability of and graded regulation of cardiac EC coupling appear paradoxical. It is now well established that this gradation results from the stochastic recruitment of varying numbers of elementary local release events, which may themselves be regenerative, and which can be directly observed as calcium sparks. Ryanodine receptors (RyRs) are clustered in dense lattices, and most calcium sparks are now believed to involve activation of multiple RyRs. This implies that local CICR is regenerative, requiring a mechanism to terminate it. It was initially assumed that this mechanism was inactivation of the RyR, but during the decade since the discovery of sparks, no sufficiently strong inactivation mechanism has been demonstrated in vitro and all empirically determined gating schemes for the RyR give unstable EC coupling in Monte Carlo simulations. We consider here possible release termination mechanisms. Stochastic attrition is the spontaneous decay of active clusters due to random channel closure; calculations show that it is much too slow unless assisted by another process. Calcium-dependent RyR inactivation involving third-party proteins remains a viable but speculative mechanism; current candidates include calmodulin and sorcin. Local depletion of SR release terminal calcium could terminate release, however calculations and measurements leave it uncertain whether a sufficient diffusion resistance exists within the SR to sustain such depletion. Depletion could be assisted by dependence of RyR activity on SR lumenal [Ca(2+)]. There is substantial evidence for such lumenal activation, but it is not clear if it is a strong enough effect to account for the robust termination of sparks. The existence of direct interactions

Drug-sensing hydrogels for the inducible release of biopharmaceuticals

NASA Astrophysics Data System (ADS)

Ehrbar, Martin; Schoenmakers, Ronald; Christen, Erik H.; Fussenegger, Martin; Weber, Wilfried

2008-10-01

Drug-dependent dissociation or association of cellular receptors represents a potent pharmacologic mode of action for regulating cell fate and function. Transferring the knowledge of pharmacologically triggered protein-protein interactions to materials science will enable novel design concepts for stimuli-sensing smart hydrogels. Here, we show the design and validation of an antibiotic-sensing hydrogel for the trigger-inducible release of human vascular endothelial growth factor. Genetically engineered bacterial gyrase subunit B (GyrB) (ref. 4) coupled to polyacrylamide was dimerized by the addition of the aminocoumarin antibiotic coumermycin, resulting in hydrogel formation. Addition of increasing concentrations of clinically validated novobiocin (Albamycin) dissociated the GyrB subunits, thereby resulting in dissociation of the hydrogel and dose- and time-dependent liberation of the entrapped protein pharmaceutical VEGF121 for triggering proliferation of human umbilical vein endothelial cells. Pharmacologically controlled hydrogels have the potential to fulfil the promises of stimuli-sensing materials as smart devices for spatiotemporally controlled delivery of drugs within the patient.

Effects of Bidens pilosa L. var. radiata SCHERFF treated with enzyme on histamine-induced contraction of guinea pig ileum and on histamine release from mast cells.

PubMed

Matsumoto, Takayuki; Horiuchi, Masako; Kamata, Katsuo; Seyama, Yoshiyuki

2009-06-01

The medical mechanism against type I allergies is to block the release or production of chemical mediators from mast cells or to block the H(1)-receptor signaling. We previously reported that the anti-allergic action of the dry powder from Bidens pilosa L. var. radiata SCHERFF treated with the enzyme cellulosine (eMMBP) was dependent on the inhibition of histamine release from mast cells. Here, we investigate that the effect of fractions in eMMBP on the histamine-induced contraction in guinea pig ileum and on the release of histamine in rat peritoneal mast cells. The histamine-induced contraction in guinea pig ileum is dose-dependently inhibited by ketotifen, an antagonist of H(1)-receptor. Fractions contained caffeic acid, caffeoylquinic acid and fractions contained flavonoids such as hyperin and isoquercitrin in eMMBP inhibit histamine release from mast cells, but only flavonoids such as hyperin, isoquercitrin and rutin suppress the histamine-induced contraction in guinea pig ileum. Moreover, the histamine-induced contraction was not affected by caffeic acid, however, such contraction was significantly inhibited by rutin. These results suggest that the primary antagonists of H(1)- receptor are different from the components in eMMBP that inhibit histamine release, and that these components participate in the anti-allergic activity of eMMBP.

The role of adenosine A1 and A2A receptors in the caffeine effect on MDMA-induced DA and 5-HT release in the mouse striatum.

PubMed

Górska, A M; Gołembiowska, K

2015-04-01

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") popular as a designer drug is often used with caffeine to gain a stronger stimulant effect. MDMA induces 5-HT and DA release by interaction with monoamine transporters. Co-administration of caffeine and MDMA may aggravate MDMA-induced toxic effects on DA and 5-HT terminals. In the present study, we determined whether caffeine influences DA and 5-HT release induced by MDMA. We also tried to find out if adenosine A1 and A2A receptors play a role in the effect of caffeine by investigating the effect of the selective adenosine A1 and A2A receptor antagonists, DPCPX and KW 6002 on DA and 5-HT release induced by MDMA. Mice were treated with caffeine (10 mg/kg) and MDMA (20 or 40 mg/kg) alone or in combination. DA and 5-HT release in the mouse striatum was measured using in vivo microdialysis. Caffeine exacerbated the effect of MDMA on DA and 5-HT release. DPCPX or KW 6002 co-administered with MDMA had similar influence as caffeine, but KW 6002 was more potent than caffeine or DPCPX. To exclude the contribution of MAO inhibition by caffeine in the caffeine effect on MDMA-induced increase in DA and 5-HT, we also tested the effect of the nonxanthine adenosine receptor antagonist CGS 15943A lacking properties of MAO activity modification. Our findings indicate that adenosine A1 and A2A receptor blockade may account for the caffeine-induced exacerbation of the MDMA effect on DA and 5-HT release and may aggravate MDMA toxicity.

From the Cover: 7,8-Dihydroxyflavone Rescues Lead-Induced Impairment of Vesicular Release: A Novel Therapeutic Approach for Lead Intoxicated Children.

PubMed

Zhang, Xiao-Lei; McGlothan, Jennifer L; Miry, Omid; Stansfield, Kirstie H; Loth, Meredith K; Stanton, Patric K; Guilarte, Tomás R

2018-01-01

Childhood lead (Pb2+) intoxication is a public health problem of global proportion. Lead exposure during development produces multiple effects on the central nervous system including impaired synapse formation, altered synaptic plasticity, and learning deficits. In primary hippocampal neurons in culture and hippocampal slices, Pb2+ exposure inhibits vesicular release and reduces the number of fast-releasing sites, an effect associated with Pb2+ inhibition of NMDA receptor-mediated trans-synaptic Brain-Derived Neurotrophic Factor (BDNF) signaling. The objective of this study was to determine if activation of TrkB, the cognate receptor for BDNF, would rescue Pb2+-induced impairments of vesicular release. Rats were chronically exposed to Pb2+ prenatally and postnatally until 50 days of age. This chronic Pb2+ exposure paradigm enhanced paired-pulse facilitation of synaptic potentials in Schaffer collateral-CA1 synapses in the hippocampus, a phenomenon indicative of reduced vesicular release probability. Decreased vesicular release probability was confirmed by both mean-variance analysis and direct 2-photon imaging of vesicular release from hippocampal slices of rats exposed to Pb2+in vivo. We also found a Pb2+-induced impairment of calcium influx in Schaffer collateral-CA1 synaptic terminals. Intraperitoneal injections of Pb2+ rats with the TrkB receptor agonist 7,8-dihydroxyflavone (5 mg/kg) for 14-15 days starting at postnatal day 35, reversed all Pb2+-induced impairments of presynaptic transmitter release at Schaffer collateral-CA1 synapses. This study demonstrates for the first time that in vivo pharmacological activation of TrkB receptors by small molecules such as 7,8-dihydroxyflavone can reverse long-term effects of chronic Pb2+ exposure on presynaptic terminals, pointing to TrkB receptor activation as a promising therapeutic intervention in Pb2+-intoxicated children. © The Author 2017. Published by Oxford University Press on behalf of the Society of

The Nitric Oxide Donor SNAP-Induced Amino Acid Neurotransmitter Release in Cortical Neurons. Effects of Blockers of Voltage-Dependent Sodium and Calcium Channels

PubMed Central

Merino, José Joaquín; Arce, Carmen; Naddaf, Ahmad; Bellver-Landete, Victor; Oset-Gasque, Maria Jesús; González, María Pilar

2014-01-01

Background The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neuronal communication. NO induces the release of amino acid neurotransmitters but the underlying mechanisms remain to be elucidated. Findings The aim of this work was to study the effect of NO on amino acid neurotransmitter release (Asp, Glu, Gly and GABA) in cortical neurons as well as the mechanism underlying the release of these neurotransmitters. Cortical neurons were stimulated with SNAP, a NO donor, and the release of different amino acid neurotransmitters was measured by HPLC. The involvement of voltage dependent Na+ and Ca2+ channels as well as cGMP in its mechanism of action was evaluated. Conclusions Our results indicate that NO induces release of aspartate, glutamate, glycine and GABA in cortical neurons and that this release is inhibited by ODQ, an inhibitor of soluble guanylate cyclase. Thus, the NO effect on amino acid neurotransmission could be mediated by cGMP formation in cortical neurons. Our data also demonstrate that the Na+ and Ca2+ voltage- dependent calcium channels are involved in the NO effects on cortical neurons. PMID:24598811

The nitric oxide donor SNAP-induced amino acid neurotransmitter release in cortical neurons. Effects of blockers of voltage-dependent sodium and calcium channels.

PubMed

Merino, José Joaquín; Arce, Carmen; Naddaf, Ahmad; Bellver-Landete, Victor; Oset-Gasque, Maria Jesús; González, María Pilar

2014-01-01

The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neuronal communication. NO induces the release of amino acid neurotransmitters but the underlying mechanisms remain to be elucidated. The aim of this work was to study the effect of NO on amino acid neurotransmitter release (Asp, Glu, Gly and GABA) in cortical neurons as well as the mechanism underlying the release of these neurotransmitters. Cortical neurons were stimulated with SNAP, a NO donor, and the release of different amino acid neurotransmitters was measured by HPLC. The involvement of voltage dependent Na+ and Ca2+ channels as well as cGMP in its mechanism of action was evaluated. Our results indicate that NO induces release of aspartate, glutamate, glycine and GABA in cortical neurons and that this release is inhibited by ODQ, an inhibitor of soluble guanylate cyclase. Thus, the NO effect on amino acid neurotransmission could be mediated by cGMP formation in cortical neurons. Our data also demonstrate that the Na+ and Ca2+ voltage- dependent calcium channels are involved in the NO effects on cortical neurons.

Carbon monoxide releasing molecule induces endothelial nitric oxide synthase activation through a calcium and phosphatidylinositol 3-kinase/Akt mechanism.

PubMed

Yang, Po-Min; Huang, Yu-Ting; Zhang, Yu-Qi; Hsieh, Chia-Wen; Wung, Being-Sun

2016-12-01

The production of nitric oxide (NO) by endothelial NO synthase (eNOS) plays a major role in maintaining vascular homeostasis. This study elucidated the potential role of carbon monoxide (CO)-releasing molecules (CORMs) in NO production and explored the underlying mechanisms in endothelial cells. We observed that 25μM CORM-2 could increase NO production and stimulate an increase in the intracellular Ca 2+ level. Furthermore, ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetra acetic acid caused CORM-2-induced NO production, which was abolished by 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetraacetoxy-methyl ester (BAPTA-AM), indicating that intracellular Ca 2+ release plays a major role in eNOS activation. The inhibition of the IP3 receptor diminished the CORM-2-induced intracellular Ca 2+ increase and NO production. Furthermore, CORM-2 induced eNOS Ser 1179 phosphorylation and eNOS dimerization, but it did not alter eNOS expression. CORM-2 (25μM) also prolonged Akt phosphorylation, lasting for at least 12h. Pretreatment with phosphatidylinositol 3-kinase inhibitors (wortmannin or LY294002) inhibited the increases in NO production and phosphorylation but did not affect eNOS dimerization. CORM-2-induced eNOS Ser 1179 phosphorylation was intracellularly calcium-dependent, because pretreatment with an intracellular Ca 2+ chelator (BAPTA-AM) inhibited this process. Although CORM-2 increases intracellular reactive oxygen species (ROS), pretreatment with antioxidant enzyme catalase and N-acetyl-cysteine did not abolish the CORM-2-induced eNOS activity or phosphorylation, signifying that ROS is not involved in this activity. Hence, CORM-2 enhances eNOS activation through intracellular calcium release, Akt phosphorylation, and eNOS dimerization. Copyright © 2016 Elsevier Inc. All rights reserved.

Light-induced protoporphyrin release from erythrocytes in erythropoietic protoporphyria.

PubMed Central

Sandberg, S; Brun, A

1982-01-01

The photohemolysis of normal erythrocytes incubated with protoporphyrin is reduced in the presence of albumin. When globin is added to normal erythrocytes loaded with protoporphyrin, protoporphyrin is bound to globin. During irradiation protoporphyrin moves from globin to the erythrocyte membrane and photohemolysis is initiated. Erythrocytes in patients with erythropoietic protoporphyria contain large amounts of protoporphyrin bound to hemoglobin. Upon irradiation of these cells in the absence of albumin, 40% of protoporphyrin and 80% of hemoglobin is released after 240 kJ/m2. The released protoporphyrin is hemoglobin bound. In contrast, when albumin is present only 8% of hemoglobin is released whereas protoporphyrin is released to 76%. The released protoporphyrin is albumin bound. A hypothesis for the release of erythrocyte protoporphyrin in erythropoietic protoporphyria without simultaneous hemolysis is proposed. Upon irradiation protoporphyrin photodamages its binding sites on hemoglobin, moves through the plasma membrane, and is bound to albumin in plasma. PMID:7107898

Cell Signaling and Neurotoxicity: 3H-Arachidonic acid release (Phospholipase A2) in cerebellar granule neurons

EPA Science Inventory

Cell signaling is a complex process which controls basic cellular activities and coordinates actions to maintain normal cellular homeostasis. Alterations in signaling processes have been associated with neurological diseases such as Alzheimer's and cerebellar ataxia, as well as, ...

Drug release through liposome pores.

PubMed

Dan, Nily

2015-02-01

Electrical, ultrasound and other types of external fields are known to induce the formation of pores in cellular and model membranes. This paper examines drug release through field induced liposome pores using Monte Carlo simulations. We find that drug release rates vary as a function of pore size and spacing, as well as the overall fraction of surface area covered by pores: The rate of release from liposomes is found to increase rapidly with pore surface coverage, approaching that of the fully ruptured liposome at fractional pore areas. For a given pore surface coverage, the pore size affects the release rate in the limit of low coverage, but not when the pores cover a relatively high fraction of the liposome surface area. On the other hand, for a given pore size and surface coverage, the distribution of pores significantly affects the release in the limit of high surface coverage: The rate of release from a liposome covered with a regularly spaced array of pores is, in this limit, higher than the release rate from (most) systems where the pores are distributed randomly on the liposome surface. In contrast, there is little effect of the pore distribution on release when the pore surface coverage is low. The simulation results are in good agreement with the predictions of detailed diffusion models. Copyright © 2014 Elsevier B.V. All rights reserved.

Naegleria fowleri Lysate Induces Strong Cytopathic Effects and Pro-inflammatory Cytokine Release in Rat Microglial Cells

PubMed Central

Lee, Yang-Jin; Park, Chang-Eun; Kim, Jong-Hyun; Sohn, Hae-Jin; Lee, Jinyoung; Jung, Suk-Yul

2011-01-01

Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A 51Cr release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-α, IL-6, and IL-1β, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response. PMID:22072830

Naegleria fowleri lysate induces strong cytopathic effects and pro-inflammatory cytokine release in rat microglial cells.

PubMed

Lee, Yang-Jin; Park, Chang-Eun; Kim, Jong-Hyun; Sohn, Hae-Jin; Lee, Jinyoung; Jung, Suk-Yul; Shin, Ho-Joon

2011-09-01

Naegleria fowleri, a ubiquitous free-living ameba, causes fatal primary amebic meningoencephalitis in humans. N. fowleri trophozoites are known to induce cytopathic changes upon contact with microglial cells, including necrotic and apoptotic cell death and pro-inflammatory cytokine release. In this study, we treated rat microglial cells with amebic lysate to probe contact-independent mechanisms for cytotoxicity, determining through a combination of light microscopy and scanning and transmission electron microscopy whether N. fowleri lysate could effect on both necrosis and apoptosis on microglia in a time- as well as dose-dependent fashion. A (51)Cr release assay demonstrated pronounced lysate induction of cytotoxicity (71.5%) toward microglial cells by 24 hr after its addition to cultures. In an assay of pro-inflammatory cytokine release, microglial cells treated with N. fowleri lysate produced TNF-α, IL-6, and IL-1β, though generation of the former 2 cytokines was reduced with time, and that of the last increased throughout the experimental period. In summary, N. fowleri lysate exerted strong cytopathic effects on microglial cells, and elicited pro-inflammatory cytokine release as a primary immune response.

Infrared neural stimulation induces intracellular Ca2+ release mediated by phospholipase C.

PubMed

Moreau, David; Lefort, Claire; Pas, Jolien; Bardet, Sylvia M; Leveque, Philippe; O'Connor, Rodney P

2018-02-01

The influence of infrared laser pulses on intracellular Ca 2+ signaling was investigated in neural cell lines with fluorescent live cell imaging. The probe Fluo-4 was used to measure Ca 2+ in HT22 mouse hippocampal neurons and nonelectrically excitable U87 human glioblastoma cells exposed to 50 to 500 ms infrared pulses at 1470 nm. Fluorescence recordings of Fluo-4 demonstrated that infrared stimulation induced an instantaneous intracellular Ca 2+ transient with similar dose-response characteristics in hippocampal neurons and glioblastoma cells (half-maximal effective energy density EC 50 of around 58 J.cm -2 ). For both type of cells, the source of the infrared-induced Ca 2+ transients was found to originate from intracellular stores and to be mediated by phospholipase C and IP 3 -induced Ca 2+ release from the endoplasmic reticulum. The activation of phosphoinositide signaling by IR light is a new mechanism of interaction relevant to infrared neural stimulation that will also be widely applicable to nonexcitable cell types. The prospect of infrared optostimulation of the PLC/IP 3 cell signaling cascade has many potential applications including the development of optoceutical therapeutics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-density lipoproteins induce a rapid and transient release of Ca2+ in cultured fibroblasts.

PubMed Central

Pörn, M I; Akerman, K E; Slotte, J P

1991-01-01

Several different cell types showed increased rates of proliferation and cholesterol mobilization in response to treatment with high-density lipoprotein (HDL). This would suggest that one main function of HDL is the activation of signal pathways in cells. In the current study we have used the fluorescent indicator fura-2 to monitor the level of cytosolic Ca2+ ([Ca2+]i) in human skin fibroblasts. Exposure of subconfluent as well as confluent fibroblasts to HDL3 (20-60 micrograms/ml) resulted in a rapid and transient increase in [Ca2+]i. Sequential additions of HDL3 resulted in diminished rises in [Ca2+]i. The transient rise in [Ca2+]i was observed with HDL prepared from plasma either by conventional ultracentrifugation or by precipitation with dextran sulphate. Chelation of the extracellular Ca2+ with EGTA prior to the addition of HDL3 did not prevent the HDL3-induced rise in [Ca2+]i, suggesting that the mobilized Ca2+ was derived mainly from intracellular stores. Covalent modification of the apoproteins of HDL3 with dimethyl suberimidate or tetranitromethane did not inhibit the HDL3-induced rise in [Ca2+]i. This indicates that the binding of HDL3 to cell surface receptors may not be necessary for the mobilization of intracellular Ca2+. Moreover, the Ca(2+)-releasing effect of HDL3 was not inhibited by the presence of albumin (1%, w/v) in the extracellular medium, suggesting that non-esterified fatty acids were not the cause of the increased [Ca2+]i. The exposure of fibroblasts to lysophosphatidic acid, a potent mitogen and Ca(2+)-releasing agent, before addition of HDL3 completely inhibited the HDL3-induced rise in [Ca2+]i. Furthermore, phorbol 12-myristate 13-acetate blocked the HDL3-induced rise in [Ca2+]i. The results of this study imply that exposure of cells to HDL generates an intracellular signal which is induced by a component of the lipid fraction. PMID:1930148

Changes in presynaptic release, but not reuptake, of bioamines induced by long-term antidepressant treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolzhenko, A.T.; Komissarov, I.V.

1986-10-01

This paper describes an investigation into the effect of long-term administration of antidepressants on neuronal uptake of NA and 5-HT and on their release, induced by electrical stimulation, in rat brain slices. The effects of the test substances on neuronal uptake of /sup 14/C-NA and /sup 3/H-5-HT by the slices was investigated. Values of IC/sub 50/ and EC/sub 2/ were found and compared in the experiments and control. The inhibitory effect of clonidine (10/sup -4/ M) and of 5-HT (10/sup -5/ M) on presynaptic release of /sup 14/C-NA and /sup 3/H-5-HT also was studied in brain slices from intact ratsmore » and rats treated for two weeks with antidepressants.« less

Release of Membrane-associated Mucins from Ocular Surface Epithelia

PubMed Central

Blalock, Timothy D.; Spurr-Michaud, Sandra J.; Tisdale, Ann S.; Gipson, Ilene K.

2008-01-01

Purpose Three membrane-associated mucins (MAMs)—MUC1, MUC4 and MUC16—are expressed at the ocular surface epithelium. Soluble forms of MAMs are detected in human tears, but the mechanisms of their release from the apical cells are unknown. The purpose of this study was to identify physiologic agents that induce ocular surface MAM release. Methods An immortalized human corneal-limbal epithelial cell line (HCLE) expressing the same MAMs as native tissue was used. An antibody specific to MUC16’s cytoplasmic tail was developed to confirm that only the extracellular domain is released into the tear fluid or culture media. Effects of agents that have been shown to be present in tears or are implicated in release/shedding of MAMs in other epithelia (neutrophil elastase, tumor necrosis factor (TNF), TNF-α-converting enzyme, and matrix metalloproteinases-7 and –9) were assessed on HCLE cells. HCLE cell surface proteins were biotinylated to measure efficiency of induced MAM release and surface restoration. Effects of induced release on surface barrier function were measured by rose bengal dye penetrance. Results MUC16 in tears and in HCLE-conditioned medium lacked the cytoplasmic tail. TNF induced release of MUC1, MUC4, and MUC16 from the HCLE surface. Matrix metalloproteinase-7 and neutrophil elastase induced release of MUC16 but not MUC1 or MUC4. Neutrophil elastase removed 68% of MUC16—78% of which was restored to the HCLE cell surface 24 hours after release. Neutrophil elastase-treated HCLE cells showed significantly reduced rose bengal dye exclusion. Conclusions Results suggest that extracellular domains of MUC1, 4, and 16 can be released from the ocular surface by agents present in tears. Neutrophil elastase and TNF present in higher amounts in dry eye patients’ tears may cause MAM release—allowing rose bengal staining. PMID:18436821

The effects of monobromobimane on calcium and phenylarsineoxide-induced mitochondrial swelling and cytochrome C release in isolated brain mitochondria.

PubMed

Abe, Tsutomu; Takagi, Norio; Nakano, Midori; Tanonaka, Kouichi; Takeo, Satoshi

2004-04-01

A possible involvement of inhibitory effects of monobromobimane (MBM), a thiol reagent, on the swelling and the release of cytochrome c in the isolated brain mitochondria was examined. MBM dose-dependently inhibited the calcium and phenylarsineoxide-induced mitochondrial swelling and cytochrome c release. Significant relationships between mitochondrial swelling and cytochrome c release were detected. Furthermore, effects of in vivo treatment with MBM on neuronal cell damage after transient (15 min) global ischemia in rats were examined. Infusion of MBM (1 or 3 microg/animal) to cerebral ventricles attenuated an increased number of TUNEL-positive cells and neuronal cell death in the hippocampal CA1 region at 72 h of reperfusion. These results suggest that MBM may have an ability to inhibit mitochondria-associated apoptotic pathways through attenuation of the mitochondrial swelling and the release of cytochrome c.

Mangiferin alleviates hypertension induced by hyperuricemia via increasing nitric oxide releases.

PubMed

Yang, Hua; Bai, Wenwei; Gao, Lihui; Jiang, Jun; Tang, Yingxi; Niu, Yanfen; Lin, Hua; Li, Ling

2018-06-06

Mangiferin, a natural glucosyl xanthone, was confirmed to be an effective uric acid (UA)- lowering agent with dual action of inhibiting production and promoting excretion of UA. In this study, we aimed to evaluate the effect of mangiferin on alleviating hypertension induced by hyperuricemia. Mangiferin (30, 60, 120 mg/kg) was administered intragastrically to hyperuricemic rats induced by gavage with potassium oxonate (750 mg/kg). Systolic blood pressure (SBP), serum levels of UA, nitric oxide (NO), C-reactionprotein (CRP) and ONOO - were measured. The mRNA and protein levels of endothelial nitric oxide synthase (eNOS), intercellular adhesion molecule-1 (ICAM-1), CRP were also analyzed. Human umbilical vein endothelial cells (HUVECs) were used in vitro studies. Administration of mangiferin significantly decreased the serum urate level and SBP at 8 weeks and last to 12 weeks. Further more, mangiferin could increase the release of NO and decrease the level of CRP in blood. In addition, mangiferin reversed the protein expression of eNOS, CRP, ICAM-1 and ONOO - in aortic segments in hyperuricemic rats. The results in vitro were consistent with the observed results in vivo. Taken together, these data suggested that mangiferin has played an important part in alleviating hypertension induced by hyperuricemia via increasing NO secretion and improving endothelial function. Copyright © 2018 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Neural control of Substance P-induced upregulation and release of macrophage migration inhibitory factor in the rat bladder

PubMed Central

Vera, Pedro L.; Wang, Xihai; Meyer-Siegler, Katherine L.

2009-01-01

OBJECTIVE Macrophage migration inhibitory factor (MIF) is increased in the intraluminal fluid after experimental inflammation and mediates pro-inflammatory effects on the bladder. We examined the contribution of nerve activity and of specific neurotransmitter systems on the mechanism of MIF release from the bladder during inflammation. MATERIALS & METHODS Male Sprague-Dawley rats were anesthetized, bladders were emptied and filled with saline. Rats received saline (s.c.; control; 0.1 ml/100 g bodyweight) or substance P (40 μg/kg in saline; s.c.; 0.1 ml/100 g bodyweight) and also received hexamethonium (50 mg/kg;i.p.; in saline; 0.1 ml/100 g body weight); intravesical lidocaine (2%; 0.3 ml), atropine (3 mg/kg in saline; i.v.; 0.1 ml/100 g body weight), propranolol (3 mg/kg in saline; i.v.; 0.1 ml/100 g body weight) or phentolamine (10 mg/kg in saline; i.v.; 0.1 ml/100 g body weight). After of 1 hour, the intravesical fluid was removed and the bladder was excised. MIF levels in the intraluminal fluid were measured by ELISA and Western-blotting. MIF expression in bladder homogenates was examined using RT-PCR. RESULTS Either intravesical lidocaine or ganglionic blockage with hexamethonium prevented Substance P-induced MIF release. In addition, pretreatment with atropine and phentolamine, but not propranolol, also prevented MIF release. MIF upregulation in the bladder, while increased with Substance P treatment, was only prevented by intravesical lidocaine. CONCLUSION Substance P-induced MIF release in the bladder is mediated through nerve activation. Post-ganglionic parasympathetic (via muscarinic receptors) and sympathetic (via alpha-adrenergic receptors) fibers mediate MIF release while activation of bladder afferent nerve terminals upregulate MIF. PMID:18499160

Agonist-induced β2-adrenoceptor desensitization and downregulation enhance pro-inflammatory cytokine release in human bronchial epithelial cells.

PubMed

Oehme, Susanne; Mittag, Anja; Schrödl, Wieland; Tarnok, Attila; Nieber, Karen; Abraham, Getu

2015-02-01

It is not clear whether increased asthma severity associated with long-term use of β2-adrenoceptor (β2-AR) agonists can be attributed to receptor degradation and increased inflammation. We investigated the cross-talk between β-AR agonist-mediated effects on β2-AR function and expression and cytokine release in human bronchial epithelial cells. In 16HBE14o(-) cells grown in the presence and absence of β-AR agonists and/or antagonists, the β2-AR density was assessed by radioligand binding; the receptor protein and mRNA was determined using laser scanning cytometer and RT-PCR; cAMP generation, the cytokines IL-6 and IL-8 release were determined using AlphaScreen Assay and ELISA, respectively. Isoprenaline (ISO) and salbutamol (Salbu) induced a concentration- and time-dependent significant decrease in β2-AR density. Both Salbu and ISO reduced cAMP generation in a concentration-dependent manner while in same cell culture the IL-6 and IL-8 release was significantly enhanced. These effects were antagonized to a greater extent by ICI 118.551 than by propranolol, but CGP 20712A had no effect. Reduction of the β2-AR protein and mRNA could be seen when cells were treated with ISO for 24 h. Our findings indicate a direct link between cytokine release and altered β2-AR expression and function in airway epithelial cells. β2-AR desensitization and downregulation induced by long-term treatment with β2-AR agonists during asthma may account for adverse reactions also due to enhanced release of pro-inflammatory mediators and should, thus, be considered in asthma therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tph2 gene deletion enhances amphetamine-induced hypermotility: effect of 5-HT restoration and role of striatal noradrenaline release.

PubMed

Carli, Mirjana; Kostoula, Chrysaugi; Sacchetti, Giuseppina; Mainolfi, Pierangela; Anastasia, Alessia; Villani, Claudia; Invernizzi, Roberto William

2015-11-01

Variants of tryptophan hydroxylase-2 (Tph2), the gene encoding enzyme responsible for the synthesis of brain serotonin (5-HT), have been associated with neuropsychiatric disorders, substance abuse and addiction. This study assessed the effect of Tph2 gene deletion on motor behavior and found that motor activity induced by 2.5 and 5 mg/kg amphetamine was enhanced in Tph2(-/-) mice. Using the in vivo microdialysis technique we found that the ability of amphetamine to stimulate noradrenaline (NA) release in the striatum was reduced by about 50% in Tph2(-/-) mice while the release of dopamine (DA) was not affected. Tph2 deletion did not affect the release of NA and DA in the prefrontal cortex. The role of endogenous 5-HT in enhancing the effect of amphetamine was confirmed showing that treatment with the 5-HT precursor 5-hydroxytryptophan (10 mg/kg) restored tissue and extracellular levels of brain 5-HT and the effects of amphetamine on striatal NA release and motor activity in Tph2(-/-) mice. Treatment with the NA precursor dihydroxyphenylserine (400 mg/kg) was sufficient to restore the effect of amphetamine on striatal NA release and motor activity in Tph2(-/-) mice. These findings indicate that amphetamine-induced hyperactivity is attenuated by endogenous 5-HT through the inhibition of striatal NA release. Tph2(-/-) mice may be a useful preclinical model to assess the role of 5-HT-dependent mechanisms in the action of psychostimulants. Acute sensitivity to the motor effects of amphetamine has been associated to increased risk of psychostimulant abuse. Here, we show that deletion of Tph2, the gene responsible for brain 5-HT synthesis, enhances the motor effect of amphetamine in mice through the inhibition of striatal NA release. This suggests that Tph2(-/-) mice is a useful preclinical model to assess the role of 5-HT-dependent mechanisms in psychostimulants action. Tph2, tryptophan hydroxylase-2. © 2015 International Society for Neurochemistry.

Calcium buffering properties of sarcoplasmic reticulum and calcium-induced Ca2+ release during the quasi-steady level of release in twitch fibers from frog skeletal muscle

PubMed Central

Fénelon, Karine; Lamboley, Cédric R.H.; Carrier, Nicole

2012-01-01

Experiments were performed to characterize the properties of the intrinsic Ca2+ buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([CaT]SR and [Ca2+]SR) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca2+ indicator). Results indicate SR Ca2+ buffering was consistent with a single cooperative-binding component or a combination of a cooperative-binding component and a linear binding component accounting for 20% or less of the bound Ca2+. Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca2+]SR and [CaT]SR are 0.67 and 17.1 mM, respectively, and the dissociation constant, Hill coefficient, and concentration of the Ca-binding sites are 0.78 mM, 3.0, and 44 mM, respectively. This information can be used to calculate a variable proportional to the Ca2+ permeability of the SR, namely d[CaT]SR/dt ÷ [Ca2+]SR (denoted release permeability), in experiments in which only [CaT]SR or [Ca2+]SR is measured. In response to a voltage-clamp step to −20 mV at 15°C, the release permeability reaches an early peak followed by a rapid decline to a quasi-steady level that lasts ∼50 ms, followed by a slower decline during which the release permeability decreases by at least threefold. During the quasi-steady level of release, the release amplitude is 3.3-fold greater than expected from voltage activation alone, a result consistent with the recruitment by Ca-induced Ca2+ release of 2.3 SR Ca2+ release channels neighboring each channel activated by its associated voltage sensor. Release permeability at −60 mV increases as [CaT]SR decreases from its resting physiological level to ∼0.1 of this level. This result argues against a release termination mechanism proposed in mammalian muscle fibers in which a luminal sensor of [Ca2+]SR inhibits release when [CaT]SR declines to a low level

Calcium buffering properties of sarcoplasmic reticulum and calcium-induced Ca(2+) release during the quasi-steady level of release in twitch fibers from frog skeletal muscle.

PubMed

Fénelon, Karine; Lamboley, Cédric R H; Carrier, Nicole; Pape, Paul C

2012-10-01

Experiments were performed to characterize the properties of the intrinsic Ca(2+) buffers in the sarcoplasmic reticulum (SR) of cut fibers from frog twitch muscle. The concentrations of total and free calcium ions within the SR ([Ca(T)](SR) and [Ca(2+)](SR)) were measured, respectively, with the EGTA/phenol red method and tetramethylmurexide (a low affinity Ca(2+) indicator). Results indicate SR Ca(2+) buffering was consistent with a single cooperative-binding component or a combination of a cooperative-binding component and a linear binding component accounting for 20% or less of the bound Ca(2+). Under the assumption of a single cooperative-binding component, the most likely resting values of [Ca(2+)](SR) and [Ca(T)](SR) are 0.67 and 17.1 mM, respectively, and the dissociation constant, Hill coefficient, and concentration of the Ca-binding sites are 0.78 mM, 3.0, and 44 mM, respectively. This information can be used to calculate a variable proportional to the Ca(2+) permeability of the SR, namely d[Ca(T)](SR)/dt ÷ [Ca(2+)](SR) (denoted release permeability), in experiments in which only [Ca(T)](SR) or [Ca(2+)](SR) is measured. In response to a voltage-clamp step to -20 mV at 15°C, the release permeability reaches an early peak followed by a rapid decline to a quasi-steady level that lasts ~50 ms, followed by a slower decline during which the release permeability decreases by at least threefold. During the quasi-steady level of release, the release amplitude is 3.3-fold greater than expected from voltage activation alone, a result consistent with the recruitment by Ca-induced Ca(2+) release of 2.3 SR Ca(2+) release channels neighboring each channel activated by its associated voltage sensor. Release permeability at -60 mV increases as [Ca(T)](SR) decreases from its resting physiological level to ~0.1 of this level. This result argues against a release termination mechanism proposed in mammalian muscle fibers in which a luminal sensor of [Ca(2+)](SR) inhibits

Exercise induced von Willebrand Factor release -- new model for routine endothelial testing.

PubMed

Balen, Sanja; Ruzić, Alen; Mirat, Jure; Persić, Viktor

2007-01-01

Endothelial dysfunction (ED) is actively involved in the mechanism of occurrence, development and progression of all the degrees of atherosclerosis. The established impact of ED on the progress and outcome of cardiovascular diseases, together with convincing indications of a possible successful therapeutic modification, necessitate the changeover of ED assessment from experimental to a routine practice. As there is no appropriate method for a clinical practice, scientists anticipate significant research efforts in the further development. Among numerous methods already available, von Willebrand Factor (vWF) stands out significantly. In accordance with the accepted leading diagnostic role of vWF baseline levels in the group of peripheral endothelial markers, and earlier scientific observations on the absence of its expected reactivation during physical exercise, we hypothesised this promising theory. We believe that a constant stronger release of vWF in endothelial cell injury leads to the exhaustion of its stores in Weibel-Palade bodies with the consequent absence of the expected rise of concentration during the exercise. Therefore, we hypothesised that ED could be exhaustible vWF endothelopathy and the exercise induced release of vWF a new, simple, safe and reliable test for the detection of ED and monitoring of the expected therapeutic effect. In order to have a final clinical usability of the proposed diagnostic model, it is necessary to test its reliability in different pathological and risk states, and establish susceptibility in therapeutic procedures. The correlation with invasive functional angiographic tests and the flow mediated dilatation test of peripheral arteries also needs to be validated. We expect the proposed test of vWF inducibility to find its place in clinical practice, i.e. in prevention, prediction and therapy of cardiovascular diseases.

Endothelial stress induces the release of vitamin D-binding protein, a novel growth factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raymond, Marc-Andre; Desormeaux, Anik; Labelle, Andree

2005-12-23

Endothelial cells (EC) under stress release paracrine mediators that facilitate accumulation of vascular smooth muscle cells (VSCM) at sites of vascular injury. We found that medium conditioned by serum-starved EC increase proliferation and migration of VSCM in vitro. Fractionation of the conditioned medium followed by mass spectral analysis identified one bioactive component as vitamin D-binding protein (DBP). DBP induced both proliferation and migration of VSMC in vitro in association with increased phosphorylation of ERK 1/2. PD 98059, a biochemical inhibitor of ERK 1/2, abrogated these proliferative and migratory responses in VSMC. DBP is an important carrier for the vitamin-D sterols,more » 25-hydroxyvitamin-D, and 1{alpha},25-dihydroxyvitamin-D. Both sterols inhibited the activity of DBP on VSMC, suggesting that vitamin D binding sites are important for initiating the activities of DBP on VSMC. Release of DBP at sites of endothelial injury represents a novel pathway favoring accumulation of VSMC at sites of vascular injury.« less

DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway

USDA-ARS?s Scientific Manuscript database

Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the...

Inhibitors of the 5-lipoxygenase arachidonic acid pathway induce ATP release and ATP-dependent organic cation transport in macrophages.

PubMed

da Silva-Souza, Hercules Antônio; Lira, Maria Nathalia de; Costa-Junior, Helio Miranda; da Cruz, Cristiane Monteiro; Vasconcellos, Jorge Silvio Silva; Mendes, Anderson Nogueira; Pimenta-Reis, Gabriela; Alvarez, Cora Lilia; Faccioli, Lucia Helena; Serezani, Carlos Henrique; Schachter, Julieta; Persechini, Pedro Muanis

2014-07-01

We have previously described that arachidonic acid (AA)-5-lipoxygenase (5-LO) metabolism inhibitors such as NDGA and MK886, inhibit cell death by apoptosis, but not by necrosis, induced by extracellular ATP (ATPe) binding to P2X7 receptors in macrophages. ATPe binding to P2X7 also induces large cationic and anionic organic molecules uptake in these cells, a process that involves at least two distinct transport mechanisms: one for cations and another for anions. Here we show that inhibitors of the AA-5-LO pathway do not inhibit P2X7 receptors, as judged by the maintenance of the ATPe-induced uptake of fluorescent anionic dyes. In addition, we describe two new transport phenomena induced by these inhibitors in macrophages: a cation-selective uptake of fluorescent dyes and the release of ATP. The cation uptake requires secreted ATPe, but, differently from the P2X7/ATPe-induced phenomena, it is also present in macrophages derived from mice deficient in the P2X7 gene. Inhibitors of phospholipase A2 and of the AA-cyclooxygenase pathway did not induce the cation uptake. The uptake of non-organic cations was investigated by measuring the free intracellular Ca(2+) concentration ([Ca(2+)]i) by Fura-2 fluorescence. NDGA, but not MK886, induced an increase in [Ca(2+)]i. Chelating Ca(2+) ions in the extracellular medium suppressed the intracellular Ca(2+) signal without interfering in the uptake of cationic dyes. We conclude that inhibitors of the AA-5-LO pathway do not block P2X7 receptors, trigger the release of ATP, and induce an ATP-dependent uptake of organic cations by a Ca(2+)- and P2X7-independent transport mechanism in macrophages. Copyright © 2014 Elsevier B.V. All rights reserved.

Cytokine-induced release of ceramide-enriched exosomes as a mediator of cell death signaling in an oligodendroglioma cell line[S

PubMed Central

Podbielska, Maria; Szulc, Zdzisław M.; Kurowska, Ewa; Hogan, Edward L.; Bielawski, Jacek; Bielawska, Alicja; Bhat, Narayan R.

2016-01-01

Th1 pro-inflammatory cytokines, i.e., TNF-α and IFN-γ, in combination are known to induce cell death in several cell types, including oligodendrocytes, but the mechanism of their synergistic cytotoxicity is unclear. Although ceramide (Cer) has been implicated in cytokine- and stress-induced cell death, its intracellular levels alone cannot explain cytokine synergy. We considered the possibility that Cer released as part of extracellular vesicles may contribute to cytokine-induced synergistic cell death. Using a human oligodendroglioma (HOG) cell line as a model, here we show that exosomes derived from TNF-α-treated “donor” cells, while being mildly toxic to fresh cultures (similar to individual cytokines), induce enhanced cell death when added to IFN-γ-primed target cultures in a fashion resembling the effect of cytokine combination. Further, the sphingolipid profiles of secreted exosomes, as determined by HPLC-MS/MS, revealed that the treatment with the cytokines time-dependently induced the formation and exosomal release, in particular of C16-, C24-, and C24:1-Cer species; C16-, C24-, and C24:1-dihydroCer species; and C16-, C24-, and C24:1-SM species. Finally, exogenous C6-Cer or C16-Cer mimicked and enhanced the cytotoxic effects of the cytokines upon HOG cells, thereby supporting the cell death-signaling role of extracellular Cer. PMID:27623848

Temperature-Induced Protein Release from Water-in-Oil-in-Water Double Emulsions

PubMed Central

Rojas, Edith C.; Staton, Jennifer A.; John, Vijay T.; Papadopoulos, Kyriakos D.

2009-01-01

A model water-in-oil-in-water (W1/O/W2) double emulsion was prepared by a two-step emulsification procedure and subsequently subjected to temperature changes that caused the oil phase to freeze and thaw while the two aqueous phases remained liquid. Our previous work on individual double-emulsion globules1 demonstrated that crystallizing the oil phase (O) preserves stability, while subsequent thawing triggers coalescence of the droplets of the internal aqueous phase (W1) with the external aqueous phase (W2), termed external coalescence. Activation of this instability mechanism led to instant release of fluorescently tagged bovine serum albumin (fluorescein isothiocyanate (FITC)-BSA) from the W1 droplets and into W2. These results motivated us to apply the proposed temperature-induced globule-breakage mechanism to bulk double emulsions. As expected, no phase separation of the emulsion occurred if stored at temperatures below 18 °C (freezing point of the model oil n-hexadecane), whereas oil thawing readily caused instability. Crucial variables were identified during experimentation, and found to greatly influence the behavior of bulk double emulsions following freeze-thaw cycling. Adjustment of these variables accounted for a more efficient release of the encapsulated protein. PMID:18543998

The regulation of ATP release from the urothelium by adenosine and transepithelial potential.

PubMed

Dunning-Davies, Bryony M; Fry, Christopher H; Mansour, Dina; Ferguson, Douglas R

2013-03-01

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Stretch of the urothelium, as occurs during bladder filling, is associated with a release of ATP that is postulated to act as a sensory neurotransmitter. The regulation of ATP release is poorly understood and in particular if there is a feedback mechanism provided by ATP itself. Adenosine, a breakdown product of ATP, is a potent inhibitor of stretch-induced ATP release, acting through and A1 receptor; endogenous levels are about 0.6μM. Data are consistent with ATP release relying on the rise of intracellular Ca2+. Transepithelial potential also controls ATP release, also acting via an A1 receptor-dependent pathway. To test the hypothesis that distension-induced ATP release from the bladder urothelium is regulated by adenosine as well as changes to transurothelial potential (TEP). To examine the role of changes to intracellular [Ca(2+) ] in ATP release. Rabbit urothelium/suburothelium membranes were used in an Ussing chamber system. Distension was induced by fluid removal from the chamber bathing the serosal (basolateral) membrane face. The TEP and short-circuit current were measured. ATP was measured in samples aspirated from the serosal chamber by a luciferin-luciferase assay. Intracellular [Ca(2+) ] was measured in isolated urothelial cells using the fluorochrome Fura-2. All experiments were performed at 37°C. Distension-induced ATP release was decreased by adenosine (1-10 μm) and enhanced by adenosine deaminase and A1- (but not A2-) receptor antagonists. Distension-induced ATP release was reduced by 2-APB, nifedipine and capsazepine; capsaicin induced ATP release in the absence of distension. ATP and capsaicin, but not adenosine, generated intracellular Ca(2+) transients; adenosine did not affect the ATP-generated Ca(2+) transient. ATP release was dependent on a finite transepithelial potential. Changes to TEP, in the absence of distension, generated ATP release that was in turn reduced by adenosine

Shiga Toxin 2 and Lipopolysaccharide Induce Human Microvascular Endothelial Cells To Release Chemokines and Factors That Stimulate Platelet Function

PubMed Central

Guessous, Fadila; Marcinkiewicz, Marek; Polanowska-Grabowska, Renata; Kongkhum, Sudawadee; Heatherly, Daniel; Obrig, Tom; Gear, Adrian R. L.

2005-01-01

Shiga toxins (Stxs) produced by Shigella dysenteriae type 1 and enterohemorrhagic Escherichia coli are the most common cause of hemolytic-uremic syndrome (HUS). It is well established that vascular endothelial cells, mainly those located in the renal microvasculature, are targets for Stxs. The aim of the present research was to evaluate whether E. coli-derived Shiga toxin 2 (Stx2) incubated with human microvascular endothelial cells (HMEC-1) induces release of chemokines and other factors that might stimulate platelet function. HMEC-1 were exposed for 24 h in vitro to Stx2, lipopolysaccharide (LPS), or the Stx2-LPS combination, and chemokine production was assessed by immunoassay. More interleukin-8 was released than stromal cell-derived factor 1α (SDF-1α) or SDF-1β and RANTES. The Stx2-LPS combination potentiated chemokine release, but Stx2 alone caused more release of SDF-1α at 24 h than LPS or Stx2-LPS did. In the presence of low ADP levels, HMEC-1 supernatants activated platelet function assessed by classical aggregometry, single-particle counting, granule secretion, P-selectin exposure, and the formation of platelet-monocyte aggregates. Supernatants from HMEC-1 exposed only to Stx2 exhibited enhanced exposure of platelet P-selectin and platelet-THP-1 cell interactions. Blockade of platelet cyclooxygenase by indomethacin prevented functional activation. The chemokine RANTES enhanced platelet aggregation induced by SDF-1α, macrophage-derived chemokine, or thymus and activation-regulated chemokine in the presence of very low ADP levels. These data support the hypothesis that microvascular endothelial cells exposed to E. coli O157:H7-derived Stx2 and LPS release chemokines and other factors, which when combined with low levels of primary agonists, such as ADP, cause platelet activation and promote the renal thrombosis associated with HUS. PMID:16299328

The mast cell stabilizer sodium cromoglycate reduces histamine release and status epilepticus-induced neuronal damage in the rat hippocampus.

PubMed

Valle-Dorado, María Guadalupe; Santana-Gómez, César Emmanuel; Orozco-Suárez, Sandra Adela; Rocha, Luisa

2015-05-01

Experiments were designed to evaluate changes in the histamine release, mast cell number and neuronal damage in hippocampus induced by status epilepticus. We also evaluated if sodium cromoglycate, a stabilizer of mast cells with a possible stabilizing effect on the membrane of neurons, was able to prevent the release of histamine, γ-aminobutyric acid (GABA) and glutamate during the status epilepticus. During microdialysis experiments, rats were treated with saline (SS-SE) or sodium cromoglycate (CG-SE) and 30 min later received the administration of pilocarpine to induce status epilepticus. Twenty-four hours after the status epilepticus, the brains were used to determine the neuronal damage and the number of mast cells in hippocampus. During the status epilepticus, SS-SE group showed an enhanced release of histamine (138.5%, p = 0.005), GABA (331 ± 91%, p ≤ 0.001) and glutamate (467%, p ≤ 0.001), even after diazepam administration. One day after the status epilepticus, SS-SE group demonstrated increased number of mast cells in Stratum pyramidale of CA1 (88%, p < 0.001) and neuronal damage in dentate gyrus, CA1 and CA3. In contrast to SS-SE group, rats from the CG-SE group showed increased latency to the establishment of the status epilepticus (p = 0.048), absence of wet-dog shakes, reduced histamine (but not GABA and glutamate) release, lower number of mast cells (p = 0.008) and reduced neuronal damage in hippocampus. Our data revealed that histamine, possibly from mast cells, is released in hippocampus during the status epilepticus. This effect may be involved in the subsequent neuronal damage and is diminished with sodium cromoglycate pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hsp72 release: mechanisms and methodologies.

PubMed

Asea, Alexzander

2007-11-01

To date there are two mechanisms that are recognized by which heat shock proteins (HSP) are released from cells; a passive release mechanism, including necrotic cell death, severe blunt trauma, surgery and following infection with lytic viruses, and an active release mechanism which involves the non classical protein release pathway in which HSPs are released within highly immunologically potent exosomes and as free HSP. This chapter describes the experimental procedures that have been developed to study the mechanism by which stress induces the release of HSP72 into the circulation and addresses the biological significance of circulating HSP72 to host defense against disease.

Persian Gulf Jellyfish (Cassiopea andromeda) Venom Fractions Induce Selective Injury and Cytochrome C Release in Mitochondria Obtained from Breast Adenocarcinoma Patients

PubMed

Mirshamsi, Mohammad Reza; Omranipour, Ramesh; Vazirizadeh, Amir; Fakhri, Amir; Zangeneh, Fatemeh; Mohebbi, Gholam Hussain; Seyedian, Ramin; Pourahmad, Jalal

2017-01-01

Objective: This study was conducted to investigate whether fractions of jellyfish Cassiope andromeda venom, could selectively induce toxicity on mitochondria isolated from cancer tissue of patients with breast adenocarcinomas. Methods: Firstly, we extracted two fractions, (f1 and f2) from crude jellyfish venom by gel filtration on Sephadex G-200.Then different dilutions of these extracted fractions were applied to mitochondria isolated from human breast tumoral- and extra-tumoral tissues. Parameters of mitochondrial toxicity including generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) collapse, swelling, cytochrome c release, activation of caspase3 and apoptosis were then assayed. Result: Our results demonstrate that fraction 2 of Cassiopea andromeda crude venom significantly (P<0.05) decreased mitochondrial succinate dehydrogenase activity, increased mitochondrial ROS production, induced mitochondrial swelling, MMP collapse and cytochrome c release, activated caspase3 and induced apoptosis only in tumoral mitochondria, and not in mitochondria obtained from extra-tumoral tissue (P<0.05). Conclusion: In conclusion this study suggested that fraction 2 of Cassiopea andromeda crude venom selectively induces ROS mediated cytotoxicity by directly targeting mitochondria isolated from human breast tumor tissue. Creative Commons Attribution License

Persian Gulf Jellyfish (Cassiopea andromeda) Venom Fractions Induce Selective Injury and Cytochrome C Release in Mitochondria Obtained from Breast Adenocarcinoma Patients

PubMed Central

Mirshamsi, Mohammad Reza; Omranipour, Ramesh; Vazirizadeh, Amir; Fakhri, Amir; Zangeneh, Fatemeh; Mohebbi, Gholam Hussain; Seyedian, Ramin; Pourahmad, Jalal

2017-01-01

Objective: This study was conducted to investigate whether fractions of jellyfish Cassiope andromeda venom, could selectively induce toxicity on mitochondria isolated from cancer tissue of patients with breast adenocarcinomas. Methods: Firstly, we extracted two fractions, (f1 and f2) from crude jellyfish venom by gel filtration on Sephadex G-200. Then different dilutions of these extracted fractions were applied to mitochondria isolated from human breast tumoral- and extra-tumoral tissues. Parameters of mitochondrial toxicity including generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) collapse, swelling, cytochrome c release, activation of caspase3 and apoptosis were then assayed. Result: Our results demonstrate that fraction 2 of Cassiopea andromeda crude venom significantly (P<0.05) decreased mitochondrial succinate dehydrogenase activity, increased mitochondrial ROS production, induced mitochondrial swelling, MMP collapse and cytochrome c release, activated caspase3 and induced apoptosis only in tumoral mitochondria, and not in mitochondria obtained from extra-tumoral tissue (P<0.05). Conclusion: In conclusion this study suggested that fraction 2 of Cassiopea andromeda crude venom selectively induces ROS mediated cytotoxicity by directly targeting mitochondria isolated from human breast tumor tissue. PMID:28240847

Leptin rapidly activates PPARs in C2C12 muscle cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bendinelli, Paola; Piccoletti, Roberta; Maroni, Paola

2005-07-08

Experimental evidence suggests that leptin operates on the tissues, including skeletal muscle, also by modulating gene expression. Using electrophoretic mobility shift assays, we have shown that physiological doses of leptin promptly increase the binding of C2C12 cell nuclear extracts to peroxisome proliferator-activated receptor (PPAR) response elements in oligonucleotide probes and that all three PPAR isoforms participate in DNA-binding complexes. We pre-treated C2C12 cells with AACOCF{sub 3}, a specific inhibitor of cytosolic phospholipase A{sub 2} (cPLA{sub 2}), an enzyme that supplies ligands to PPARs, and found that it abrogates leptin-induced PPAR DNA-binding activity. Leptin treatment significantly increased cPLA{sub 2} activity, evaluatedmore » as the release of [{sup 3}H]arachidonic acid from pre-labelled C2C12 cells, as well as phosphorylation. Further, using MEK1 inhibitor PD-98059 we showed that leptin activates cPLA{sub 2} through ERK induction. These results support a direct effect of leptin on skeletal muscle cells, and suggest that the hormone may modulate muscle transcription also by precocious activation of PPARs through ERK-cPLA{sub 2} pathway.« less

Prostaglandin F2 alpha and its analogs induce release of endogenous prostaglandins in iris and ciliary muscles isolated from cat and other mammalian species.

PubMed

Yousufzai, S Y; Ye, Z; Abdel-Latif, A A

1996-09-01

Prostaglandin F2 alpha (PGF 2 alpha) and its analog latanoprost are effective in lowering intraocular pressure (IOP) in both animal and human subjects. There is mounting experimental evidence now which indicates that the IOP-lowering effect of these PGs occurs through an increased uveoscleral outflow of aqueous humor. The ciliary muscle constitutes the main resistance in this pathway. Work from several laboratories, including our own, has shown that in this smooth muscle PGF 2 alpha has little effect on cAMP accumulation or on Ca2+ mobilization. In the present study, we hypothesized that some of the effects of PGF2 alpha and its analogs may be mediated through the release of endogenous PGs. The purpose of this work was to determine whether or not PGF2 alpha and its analogs can enhance the release of endogenous PGs in iris and ciliary muscles isolated from different species. This report documents for the first time that exogenous PGF2 alpha and its analogs, PhXA85 and latanoprost, stimulate the formation of PGE2, PGD2 and PGF2 alpha in iris and ciliary muscles isolated from cat, bovine, rabbit, dog, rhesus monkey and human. PG-induced PG release was demonstrated by means of both radioimmunoassay and radiochromatography. Kinetic studies on cat iris revealed that PGF2 alpha-induced PGE2 release is time (t 1/2 = 1.7 min) and dose-dependent (EC50 = 45 nM). The increase in PGE2 release was blocked by indomethacin (Indo) and by dexamethasone in a dose-dependent manner with IC50 s of 9.2 nM and 2.6 microM, respectively. Furthermore, dexamethasone inhibited arachidonic acid (AA) release, suggesting the involvement of phospholipase A2 in PGF2 alpha-induced PG release. The data presented demonstrate that PGF2 alpha and its analogs interact with the PG receptor to stimulate phospholipase A2 and release AA for PG synthesis. Relaxation of ciliary muscle by PGF2 alpha and its analogs, via release of endogenous PGE2, a potent activator of the adenylate cyclase system, could in

An empirical approach to estimate near-infra-red photon propagation and optically induced drug release in brain tissues

NASA Astrophysics Data System (ADS)

Prabhu Verleker, Akshay; Fang, Qianqian; Choi, Mi-Ran; Clare, Susan; Stantz, Keith M.

2015-03-01

The purpose of this study is to develop an alternate empirical approach to estimate near-infra-red (NIR) photon propagation and quantify optically induced drug release in brain metastasis, without relying on computationally expensive Monte Carlo techniques (gold standard). Targeted drug delivery with optically induced drug release is a noninvasive means to treat cancers and metastasis. This study is part of a larger project to treat brain metastasis by delivering lapatinib-drug-nanocomplexes and activating NIR-induced drug release. The empirical model was developed using a weighted approach to estimate photon scattering in tissues and calibrated using a GPU based 3D Monte Carlo. The empirical model was developed and tested against Monte Carlo in optical brain phantoms for pencil beams (width 1mm) and broad beams (width 10mm). The empirical algorithm was tested against the Monte Carlo for different albedos along with diffusion equation and in simulated brain phantoms resembling white-matter (μs'=8.25mm-1, μa=0.005mm-1) and gray-matter (μs'=2.45mm-1, μa=0.035mm-1) at wavelength 800nm. The goodness of fit between the two models was determined using coefficient of determination (R-squared analysis). Preliminary results show the Empirical algorithm matches Monte Carlo simulated fluence over a wide range of albedo (0.7 to 0.99), while the diffusion equation fails for lower albedo. The photon fluence generated by empirical code matched the Monte Carlo in homogeneous phantoms (R2=0.99). While GPU based Monte Carlo achieved 300X acceleration compared to earlier CPU based models, the empirical code is 700X faster than the Monte Carlo for a typical super-Gaussian laser beam.

LPA1 receptor-mediated thromboxane A2 release is responsible for lysophosphatidic acid-induced vascular smooth muscle contraction.

PubMed

Dancs, Péter Tibor; Ruisanchez, Éva; Balogh, Andrea; Panta, Cecília Rita; Miklós, Zsuzsanna; Nüsing, Rolf M; Aoki, Junken; Chun, Jerold; Offermanns, Stefan; Tigyi, Gábor; Benyó, Zoltán

2017-04-01

Lysophosphatidic acid (LPA) has been recognized recently as an endothelium-dependent vasodilator, but several lines of evidence indicate that it may also stimulate vascular smooth muscle cells (VSMCs), thereby contributing to vasoregulation and remodeling. In the present study, mRNA expression of all 6 LPA receptor genes was detected in murine aortic VSMCs, with the highest levels of LPA 1 , LPA 2 , LPA 4 , and LPA 6 In endothelium-denuded thoracic aorta (TA) and abdominal aorta (AA) segments, 1-oleoyl-LPA and the LPA 1-3 agonist VPC31143 induced dose-dependent vasoconstriction. VPC31143-induced AA contraction was sensitive to pertussis toxin (PTX), the LPA 1&3 antagonist Ki16425, and genetic deletion of LPA 1 but not that of LPA 2 or inhibition of LPA 3 , by diacylglycerol pyrophosphate. Surprisingly, vasoconstriction was also diminished in vessels lacking cyclooxygenase-1 [COX1 knockout (KO)] or the thromboxane prostanoid (TP) receptor (TP KO). VPC31143 increased thromboxane A 2 (TXA 2 ) release from TA of wild-type, TP-KO, and LPA 2 -KO mice but not from LPA 1 -KO or COX1-KO mice, and PTX blocked this effect. Our findings indicate that LPA causes vasoconstriction in VSMCs, mediated by LPA 1 -, G i -, and COX1-dependent autocrine/paracrine TXA 2 release and consequent TP activation. We propose that this new-found interaction between the LPA/LPA 1 and TXA 2 /TP pathways plays significant roles in vasoregulation, hemostasis, thrombosis, and vascular remodeling.-Dancs, P. T., Ruisanchez, E., Balogh, A., Panta, C. R., Miklós, Z., Nüsing, R. M., Aoki, J., Chun, J., Offermanns, S., Tigyi, G., Benyó, Z. LPA 1 receptor-mediated thromboxane A 2 release is responsible for lysophosphatidic acid-induced vascular smooth muscle contraction. © FASEB.

JS-K, a nitric oxide prodrug, induces cytochrome c release and caspase activation in HL-60 myeloid leukemia cells.

PubMed

Udupi, Vidya; Yu, Margaret; Malaviya, Swati; Saavedra, Joseph E; Shami, Paul J

2006-10-01

Nitric oxide (NO) induces differentiation and apoptosis in acute myelogenous leukemia (AML) cells. The NO prodrug O2-(2,4-dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate, or JS-K, has potent antileukemic activity. JS-K induces apoptosis in HL-60 cells by a caspase-dependent mechanism. The purpose of this study was to determine the pathway through which JS-K induces apoptosis. We show that JS-K alters mitochondrial membrane potential (DeltaPsim) and induces cytochrome c release from mitochondria into the cytoplasm. Treatment with JS-K resulted in activation of Caspase (Casp) 9, Casp 3 and Casp 8. JS-K constitutes a promising lead for a new class of anti-leukemic agents.

Dopamine-induced programmed cell death is associated with cytochrome c release and caspase-3 activation in snail salivary gland cells.

PubMed

Pirger, Zsolt; Rácz, Boglárka; Kiss, Tibor

2009-02-01

PCD (programmed cell death) is a common mechanism to remove unwanted and excessive cells from organisms. In several exocrine cell types, PCD mode of release of secretory products has been reported. The molecular mechanism of the release, however, is largely unknown. Our aim was to study the molecular mechanism of saliva release from cystic cells, the specific cell type of snail SGs (salivary glands). SG cells in active feeding animals revealed multiple morphological changes characteristic of PCD. Nerve stimulation and DA (dopamine) increased the number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling)-positive cells both in inactive and feeding animals. The DA-induced PCD was prevented by TEA (tetraethylammonium chloride) and eticlopride, emphasizing the role of K channels and D2 receptors in the PCD of cystic cells. DA enhanced cyto-c (cytochrome c) translocation into the cytosol and methyl-beta-cyclodextrin prevented it, suggesting apoptosome formation and ceramide involvement in the PCD linking of the surface DA receptor to mitochondria. Western blot analysis revealed that the release of cyto-c was under the control of Bcl-2 and Bad. DA also increased the active caspase-3 in gland cells while D2 receptor antagonists and TEA attenuated it. Our results provide evidence for a type of transmitter-mediated pathway that regulates the PCD of secretory cells in a mitochondrial-caspase-dependent manner. The activation of specific molecules, such as K channels, DA receptors, cyto-c, ceramide, Bcl-2 proteins and caspase-3, but not caspase-8, was demonstrated in cells involved in the DA-induced PCD, suggesting that PCD is a physiological method for the release of saliva from SG cells.

Low dose oral pH modified release budesonide for maintenance of steroid induced remission in Crohn's disease

PubMed Central

Gross, V; Andus, T; Ecker, K; Raedler, A; Loeschke, K; Plauth, M; Rasenack, J; Weber, A; Gierend, M; Ewe, K; Scholmerich, J; Budesonide, S

1998-01-01

Background—The relapse rate after steroid induced remission in Crohn's disease is high. 
Aims—To test whether oral pH modified release budesonide (3 × 1 mg/day) reduces the relapse rate and to identify patient subgroups with an increased risk of relapse. 
Methods—In a multicentre, randomised, double blind study, 179 patients with steroid induced remission of Crohn's disease received either 3 × 1 mg budesonide (n=84) or placebo (n=95) for one year. The primary study aim was the maintenance of remission of Crohn's disease for one year. 
Results—Patient characteristics at study entry were similar for both groups. The relapse rate was 67% (56/84) in the budesonide group and 65% (62/95) in the placebo group. The relapse curves in both groups were similar. The mean time to relapse was 93.5days in the budesonide group and 67.0 days in the placebo group. No prognostic factors allowing prediction of an increased risk for relapse or definition of patient subgroups who derived benefit from low dose budesonide were found. Drug related side effects were mild and no different between the budesonide and the placebo group. 
Conclusion—Oral pH modified release budesonide at a dose of 3 × 1 mg/day is not effective for maintaining steroid induced remission in Crohn's disease. 

 Keywords: budesonide; Crohn's disease; maintenance of remission PMID:9616309

Subpopulation of store-operated Ca2+ channels regulate Ca2+-induced Ca2+ release in non-excitable cells.

PubMed

Yao, Jian; Li, Qin; Chen, Jin; Muallem, Shmuel

2004-05-14

Ca2+-induced Ca2+ release (CICR) is a well characterized activity in skeletal and cardiac muscles mediated by the ryanodine receptors. The present study demonstrates CICR in the non-excitable parotid acinar cells, which resembles the mechanism described in cardiac myocytes. Partial depletion of internal Ca2+ stores leads to a minimal activation of Ca2+ influx. Ca2+ influx through this pathway results in an explosive mobilization of Ca2+ from the majority of the stores by CICR. Thus, stimulation of parotid acinar cells in Ca2+ -free medium with 0.5 microm carbachol releases approximately 5% of the Ca2+ mobilizable by 1 mm carbachol. Addition of external Ca2+ induced the same Ca2+ release observed in maximally stimulated cells. Similar results were obtained by a short treatment with 2.5-10 microm cyclopiazonic acid, an inhibitor of the sarco/endoplasmic reticulum Ca2+ ATPase pump. The Ca2+ release induced by the addition of external Ca2+ was largely independent of IP(3)Rs because it was reduced by only approximately 30% by the inhibition of the inositol 1,4,5-trisphosphate receptors with caffeine or heparin. Measurements of Ca2+ -activated outward current and [Ca2+](i) suggested that most CICR triggered by Ca2+ influx occurred away from the plasma membrane. Measurement of the response to several concentrations of cyclopiazonic acid revealed that Ca2+ influx that regulates CICR is associated with a selective portion of the internal Ca2+ pool. The minimal activation of Ca2+ influx by partial store depletion was confirmed by the measurement of Mn2+ influx. Inhibition of Ca2+ influx with SKF96365 or 2-aminoethoxydiphenyl borate prevented activation of CICR observed on addition of external Ca2+. These findings provide evidence for activation of CICR by Ca2+ influx in non-excitable cells, demonstrate a previously unrecognized role for Ca2+ influx in triggering CICR, and indicate that CICR in non-excitable cells resembles CICR in cardiac myocytes with the exception that in

Growth hormone (GH)-releasing activity of chicken GH-releasing hormone (GHRH) in chickens.

PubMed

Harvey, S; Gineste, C; Gaylinn, B D

2014-08-01

Two peptides with sequence similarities to growth hormone releasing hormone (GHRH) have been identified by analysis of the chicken genome. One of these peptides, chicken (c) GHRH-LP (like peptide) was previously found to poorly bind to chicken pituitary membranes or to cloned and expressed chicken GHRH receptors and had little, if any, growth hormone (GH)-releasing activity in vivo or in vitro. In contrast, a second more recently discovered peptide, cGHRH, does bind to cloned and expressed cGHRH receptors and increases cAMP activity in transfected cells. The possibility that this peptide may have in vivo GH-releasing activity was therefore assessed. The intravenous (i.v.) administration of cGHRH to immature chickens, at doses of 3-100 μg/kg, significantly increased circulating GH concentrations within 10 min of injection and the plasma GH levels remained elevated for at least 30 min after the injection of maximally effective doses. The plasma GH responses to cGHRH were comparable with those induced by human (h) or porcine (p) GHRH preparations and to that induced by thyrotropin releasing hormone (TRH). In marked contrast, the i.v. injection of cGHRH-LP had no significant effect on circulating GH concentrations in immature chicks. GH release was also increased from slaughterhouse chicken pituitary glands perifused for 5 min with cGHRH at doses of 0.1 μg/ml or 1.0 μg/ml, comparable with GH responses to hGHRH1-44. In contrast, the perifusion of chicken pituitary glands with cGHRH-LP had no significant effect on GH release. In summary, these results demonstrate that cGHRH has GH-releasing activity in chickens and support the possibility that it is the endogenous ligand of the cGHRH receptor. Copyright © 2014 Elsevier Inc. All rights reserved.

Nedocromil sodium inhibits antigen-induced contraction of human lung parenchymal and bronchial strips, and the release of sulphidopeptide-leukotriene and histamine from human lung fragments.

PubMed Central

Napier, F. E.; Shearer, M. A.; Temple, D. M.

1990-01-01

1. The effects of nedocromil sodium on antigen-induced release of sulphidopeptide-leukotrienes and histamine from passively sensitized fragments of human lung, and on antigen-induced contraction of sensitized strips of human lung parenchyma and bronchus, have been studied. 2. Nedocromil sodium 0.1 and 1 microM inhibited leukotriene release from fragments of human lung by 30% and 38% respectively, and histamine release by 43% for both concentrations, but 10 microM was ineffective. The lung fragments, which were passively sensitized to house dust mite, Dermataphagoides pteronyssinus, in control experiments released leukotrienes (6.58 +/- 0.12 nmol equiv. leukotriene C4 per g, n = 6) and histamine (10.3 +/- 1.8 of total tissue histamine, n = 5) when challenged with house dust mite extract. 3. Isolated strips of human lung parenchyma, passively sensitized to D. pteronyssinus, contracted when treated with house dust mite extract to a mean value of 40% of the maximal histamine response for each strip. Nedocromil sodium 0.1 and 1 microM inhibited these contractions by 50% and 70% of the control response, but 10 microM had no inhibitory effect. 4. Isolated rings from human bronchus, also passively sensitized to D. pteronyssinus, contracted when treated with house dust mite extract to a mean value of 86% of the maximal histamine response. Nedocromil sodium 1 microM, but not 0.1 or 10 microM, inhibited contractions by 48% of the control response. 5. The therapeutic effects of nedocromil sodium in allergic asthma may depend, partly, on its inhibition of antigen-induced release of leukotrienes and histamine in human lung and its consequent inhibition of antigen-induced contractions of parenchymal and bronchial tissue. PMID:1696152

Bisphenol A induces corticotropin-releasing hormone expression in the placental cells JEG-3.

PubMed

Huang, Hui; Tan, Wenjuan; Wang, C C; Leung, Lai K

2012-11-01

Bisphenol A is utilized to make polycarbonate plastics and is an environmental pollutant. Recent research has indicated that it is an endocrine disruptor and may interfere with reproduction. Placental corticotrophin-releasing hormone (CRH) is a peptide hormone which is involved in fetal development. Increased plasma CRH is associated with elevated risk of premature delivery. In the present study, we demonstrated that bisphenol A increased CRH mRNA expression in the placental JEG-3 cells at or above 25μM. Reporter gene assay also demonstrated that bisphenol A could induce CRH gene transactivity. Since cyclic AMP response element (CRE) is a major regulatory element located in CRH promoter, the sequence-specific binding activity was investigated by using electrophoretic mobility shift assay. Our data indicated that bisphenol A increased the CRE binding activity. Western analysis further illustrated that PKA could be the signal triggering the CRE binding and CRH gene transactivation. In summary, the present study demonstrated that bisphenol A could induce CRH expression in placental cells and the underlying signal transduction pathway was also described. Copyright © 2012 Elsevier Inc. All rights reserved.

HCOOH-induced Controlled-release Hydrolysis of Microalgae (Scenedesmus) to Lactic Acid over Sn-Beta Catalyst.

PubMed

Zan, Yifan; Sun, Yuanyuan; Kong, Lingzhao; Miao, Gai; Bao, Liwei; Wang, Hao; Li, Shenggang; Sun, Yuhan

2018-06-12

Formic acid induced controlled-release hydrolysis of sugar-rich microalgae (Scenedesmus) over the Sn-Beta catalyst was found to be a highly efficient process for producing lactic acid as a platform chemical. One-pot reaction with a very high lactic acid yield of 83.0% was realized in a batch reactor using water as the solvent. Under the attack of formic acid, the cell wall of Scenedesmus was disintegrated, and hydrolysis of the starch inside the cell was strengthened in a controlled-release mode, resulting in a stable and relatively low glucose concentration. Subsequently, the Sn-Beta catalyst was employed for the efficient conversion of glucose into lactic acid with stable catalytic performance through isomerization, retro-aldol and de-/rehydration reactions. Thus, the hydrolysis of polysaccharides and the catalytic conversion of the monosaccharide into lactic acid was realized by the synergy between an organic Brønsted acid and a heterogeneous Lewis acid catalyst. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The heme oxygenase-1 inducer THI-56 negatively regulates iNOS expression and HMGB1 release in LPS-activated RAW 264.7 cells and CLP-induced septic mice.

PubMed

Park, Eun Jung; Jang, Hwa Jin; Tsoyi, Konstantin; Kim, Young Min; Park, Sang Won; Kim, Hye Jung; Lee, Jae Heun; Chang, Ki Churl

2013-01-01

The nuclear DNA binding protein high mobility group box 1 (HMGB1) has recently been suggested to act as a late mediator of septic shock. The effect of ((S)-6,7-dihydroxy-1-(4-hydroxynaphthylmethyl)-1,2,3,4-tetrahydroisoquinoline alkaloid, also known as THI-56, in an experimental model of sepsis was investigated. THI-56 exhibited potent anti-inflammatory properties in response to LPS in RAW 264.7 cells. In particular, THI-56 significantly inhibited the expression of inducible nitric oxide synthase (iNOS) and the release of HMGB1 in activated macrophages. THI-56 activated NE-F2-regulated factor 2 (Nrf-2)/heme oxygenase 1 (HO-1). The specific knockdown of the HO-1 gene by HO-1 siRNA significantly reversed the inhibitory effects of THI-56 on iNOS expression and HMGB1 release in LPS-stimulated macrophages. Importantly, THI-56 administration protected animals from death induced by either a lethal dose of LPS or cecal ligation and puncture (CLP). Furthermore, the ALT, AST, BUN, creatinine, and HMGB1 levels in the blood were significantly increased in CLP-induced septic mice, and the administration of THI-56 reduced these levels in a concentration-dependent and zinc protoporphyrin IX (ZnPPIX)-sensitive manner. In addition, the administration of THI-56 significantly ameliorated not only lung damage but also macrophage infiltration in the livers of CLP-induced septic mice, and these effects were also abrogated in the presence of ZnPPIX. Thus, we conclude that THI-56 significantly attenuates the proinflammatory response induced by LPS and reduces organ damage in a CLP-induced sepsis model through the upregulation of Nrf-2/HO-1.

Action potential-independent and pharmacologically unique vesicular serotonin release from dendrites

PubMed Central

Colgan, Lesley A.; Cavolo, Samantha L.; Commons, Kathryn G.; Levitan, Edwin S.

2012-01-01

Serotonin released within the dorsal raphe nucleus (DR) induces feedback inhibition of serotonin neuron activity and consequently regulates mood-controlling serotonin release throughout the forebrain. Serotonin packaged in vesicles is released in response to action potentials by the serotonin neuron soma and terminals, but the potential for release by dendrites is unknown. Here three-photon (3P) microscopy imaging of endogenous serotonin in living rat brain slice, immunofluorescence and immuno-gold electron microscopy detection of VMAT2 (vesicular monoamine transporter 2) establish the presence of vesicular serotonin within DR dendrites. Furthermore, activation of glutamate receptors is shown to induce vesicular serotonin release from dendrites. However, unlike release from the soma and terminals, dendritic serotonin release is independent of action potentials, relies on L-type Ca2+ channels, is induced preferentially by NMDA, and displays distinct sensitivity to the selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine. The unique control of dendritic serotonin release has important implications for DR physiology and the antidepressant action of SSRIs, dihydropyridines and NMDA receptor antagonists. PMID:23136413

Losartan increases NO release in afferent arterioles during regression of L-NAME-induced renal damage.

PubMed

Helle, Frank; Iversen, Bjarne M; Chatziantoniou, Christos

2010-05-01

Inhibition of nitric oxide synthesis (NOS) induces hypertension and heavy proteinuria. Renal structure and function have shown striking improvement after interventions targeting ANG II or endothelin (ET) receptors in rats recovering after long-term NOS inhibition. To search for mechanisms underlying losartan-assisted regression of renal disease in rodents, we measured NO release and contractility to ET in afferent arterioles (AAs) from Sprague-Dawley rats recovering for 2 wk after 4 wk of N(G)-nitro-L-arginine methyl ester treatment. Losartan administration during the recovery period decreased blood pressure (113 ± 4 vs. 146 ± 5 mmHg, P < 0.01), reduced protein/creatinine ratio more (proteinuria decrease: Δ1,836 ± 214 vs. Δ1,024 ± 180 mg/mmol, P < 0.01), and normalized microvascular hypertrophy (AA media/lumen ratio: 1.74 ± 0.05 vs. 2.09 ± 0.08, P < 0.05) compared with no treatment. In diaminofluorescein-FM-loaded AAs from losartan-treated animals, NO release (% of baseline) was increased compared with untreated animals after stimulation with 10(-7) M ACh (118 ± 4 vs. 90 ± 7%, t = 560 s, P < 0.001) and 10(-9) M ET (123 ± 4 vs. 101 ± 5%, t = 560 s, P < 0.001). There was also a blunted contractile response to 10(-7) M ET in AAs from losartan-treated animals compared with untreated animals (Δ4.01 ± 2.9 vs. Δ14.6 ± 1.7 μm, P < 0.01), which disappeared after acute NOS inhibition (Δ10.7 ± 3.7 vs. Δ12.5 ± 2.9 μm, not significant). Contractile dose responses to ET (10(-9), 10(-8), 10(-7) M) were enhanced by NOS inhibition and blunted by exogenous NO (10(-2) mM S-nitroso-N-acetyl-penicillamine) in losartan-treated but not in untreated vessels. Reducing blood pressure similar to losartan with hydralazine did not improve AA hypertrophy, ET-induced contractility, ET-induced NO release, and NO sensitivity. In conclusion, blockade of the local action of ANG II improved endothelial function in AAs, a mechanism that is likely to contribute to the beneficial

Granisetron Extended-Release Injection: A Review in Chemotherapy-Induced Nausea and Vomiting.

PubMed

Deeks, Emma D

2016-12-01

An extended-release (ER) subcutaneously injectable formulation of the first-generation 5-HT 3 receptor antagonist granisetron is now available in the USA (Sustol ® ), where it is indicated for the prevention of acute and delayed chemotherapy-induced nausea and vomiting (CINV) following moderately emetogenic chemotherapy (MEC) or anthracycline and cyclophosphamide combination chemotherapy regimens in adults. Granisetron ER is administered as a single subcutaneous injection and uses an erosion-controlled drug-delivery system to allow prolonged granisetron release. Primary endpoint data from phase III studies after an initial cycle of chemotherapy indicate that, when used as part of an antiemetic regimen, granisetron ER injection is more effective than intravenous ondansetron in preventing delayed CINV following highly emetogenic chemotherapy (HEC); is noninferior to intravenous palonosetron in preventing both acute CINV following MEC or HEC and delayed CINV following MEC; and is similar, but not superior, to palonosetron in preventing delayed CINV following HEC. The benefits of granisetron ER were seen in various patient subgroups, including those receiving anthracycline plus cyclophosphamide-based HEC, and (in an extension of one of the studies) over multiple MEC or HEC cycles. Granisetron ER injection is generally well tolerated, with an adverse event profile similar to that of ondansetron or palonosetron. Thus, granisetron ER injection expands the options for preventing both acute and delayed CINV in adults with cancer receiving MEC or anthracycline plus cyclophosphamide-based HEC.

Dental resin curing blue light induces vasoconstriction through release of hydrogen peroxide.

PubMed

Oktay, Elif Aybala; Tort, Huseyin; Yıldız, Oguzhan; Ulusoy, Kemal Gokhan; Topcu, Fulya Toksoy; Ozer, Cigdem

2018-05-26

Dental resin curing blue light (BL) is frequently used during treatments in dental clinics. However, little is known about the influence of BL irradiation on pulpal blood vessels. The aim of the present study was to investigate the mechanism of effect of BL irradiation on vascular tone. Rat aorta (RA) rings were irradiated with a BL source in organ baths, and the responses were recorded isometrically. Effect of BL irradiation on phenylephrine (PE) -precontraction and acetylcholine (ACh) -induced relaxation after PE -precontraction were obtained and compared in BL -irradiated and control RA rings. Effect of 20 min preincubation with catalase (enzyme that breaks down hydrogene peroxide, 1200 u/ml) on PE -precontraced and BL-irradiated rings was also evaluated. Total oxidative stress (TOS) and total antioxidant capacity (TAC) in BL-irradiated and control RA preparations were measured with special assay kits and spectrophotometry. BL slightly decreased ACh -induced endothelium -dependent relaxations in PE (1 μM) -precontracted RA rings (n = 6, p > 0.05 vs. control). BL induced marked contraction 23.88 + 3.10% of PE (maximum contraction) in isolated RA ring segments precontracted with PE (p < 0.05 vs. control). The contractile effect of BL was inhibited by 1200 u/ml catalase (n = 6, p < 0.05 vs. control). BL irradiation increased the level of TOS in RA rings (n = 6, p < 0.05 vs. control). TAC levels were similar in BL-irradiated and control preparations. These results suggest that BL induces contraction in RA, and the mechanism of this effect may to be through release of hydrogen peroxide. Copyright © 2018 Elsevier B.V. All rights reserved.

Microdose gonadotropin-releasing hormone agonist in the absence of exogenous gonadotropins is not sufficient to induce multiple follicle development.

PubMed

Chung, Karine; Fogle, Robin; Bendikson, Kristin; Christenson, Kamilee; Paulson, Richard

2011-01-01

Because the effectiveness of the "microdose flare" stimulation protocol often is attributed to the dramatic endogenous gonadotropin release induced by the GnRH agonist, the aim of this study was to determine whether use of microdose GnRH agonist alone could induce multiple ovarian follicle development in normal responders. Based on these data, the duration of gonadotropin rise is approximately 24 to 48 hours and is too brief to sustain continued multiple follicle growth. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Choline acetyltransferase and organic cation transporters are responsible for synthesis and propionate-induced release of acetylcholine in colon epithelium.

PubMed

Bader, Sandra; Klein, Jochen; Diener, Martin

2014-06-15

Acetylcholine is not only a neurotransmitter, but is found in a variety of non-neuronal cells. For example, the enzyme choline acetyltransferase (ChAT), catalyzing acetylcholine synthesis, is expressed by the colonic epithelium of different species. These cells release acetylcholine across the basolateral membrane after luminal exposure to propionate, a short-chain fatty acid. The functional consequence is the induction of chloride secretion, measurable as increase in short-circuit current (Isc) in Ussing chamber experiments. It is unclear how acetylcholine is produced and released by colonic epithelium. Therefore, the aim of the present study was the identification (on mRNA and protein level) and functional characterization (in Ussing chamber experiments combined with HPLC detection of acetylcholine) of transporters/enzymes in the cholinergic system of rat colonic epithelium. Immunohistochemical staining as well as RT-PCR revealed the expression of high-affinity choline transporter, ChAT, carnitine acetyltransferase (CarAT), vesicular acetylcholine transporter (VAChT), and organic cation transporters (OCT 1, 2, 3) in colonic epithelium. In contrast to blockade of ChAT with bromoacetylcholine, inhibition of CarAT with mildronate did not inhibit the propionate-induced increase in Isc, suggesting a predominant synthesis of epithelial acetylcholine by ChAT. Although being expressed, blockade of VAChT with vesamicol was ineffective, whereas inhibition of OCTs with omeprazole and corticosterone inhibited propionate-induced Isc and the release of acetylcholine into the basolateral compartment. In summary, OCTs seem to be involved in regulated acetylcholine release by colonic epithelium, which is assumed to be involved in chemosensing of luminal short-chain fatty acids by the intestinal epithelium. Copyright © 2014 Elsevier B.V. All rights reserved.

Corticotropin-releasing factor-1 receptor activation mediates nicotine withdrawal-induced deficit in brain reward function and stress-induced relapse.

PubMed

Bruijnzeel, Adrie W; Prado, Melissa; Isaac, Shani

2009-07-15

Tobacco addiction is a chronic brain disorder that is characterized by a negative affective state upon smoking cessation and relapse after periods of abstinence. Previous research has shown that blockade of corticotropin-releasing factor (CRF) receptors with a nonspecific CRF1/CRF2 receptor antagonist prevents the deficit in brain reward function associated with nicotine withdrawal and stress-induced reinstatement of extinguished nicotine-seeking in rats. The aim of these studies was to investigate the role of CRF1 and CRF2 receptors in the deficit in brain reward function associated with precipitated nicotine withdrawal and stress-induced reinstatement of nicotine-seeking. The intracranial self-stimulation (ICSS) procedure was used to assess the negative affective state of nicotine withdrawal. Elevations in brain reward thresholds are indicative of a deficit in brain reward function. Stress-induced reinstatement of nicotine-seeking was investigated in animals in which responding for intravenously infused nicotine was extinguished by substituting saline for nicotine. In the ICSS experiments, the nicotinic receptor antagonist mecamylamine elevated the brain reward thresholds of the nicotine-dependent rats but not those of the control rats. The CRF1 receptor antagonist R278995/CRA0450 but not the CRF2 receptor antagonist astressin-2B prevented the elevations in brain reward thresholds associated with precipitated nicotine withdrawal. Furthermore, R278995/CRA0450 but not astressin-2B prevented stress-induced reinstatement of extinguished nicotine-seeking. Neither R278995/CRA0450 nor astressin-2B affected operant responding for chocolate-flavored food pellets. These studies indicate that CRF(1) receptors but not CRF(2) receptors play an important role in the anhedonic-state associated with acute nicotine withdrawal and stress-induced reinstatement of nicotine-seeking.

Dimebon Inhibits Calcium-Induced Swelling of Rat Brain Mitochondria But Does Not Alter Calcium Retention or Cytochrome C Release

PubMed Central

Naga, Kranthi Kumari

2012-01-01

Dimebon was originally introduced as an antihistamine and subsequently investigated as a possible therapeutic for a variety of disorders, including Alzheimer's disease. One putative mechanism underlying the neuroprotective properties of Dimebon is inhibition of mitochondrial permeability transition, based on the observation that Dimebon inhibited the swelling of rat liver mitochondria induced by calcium and other agents that induce permeability transition. Because liver and brain mitochondria differ substantially in their properties and response to conditions associated with opening of the permeability transition pore, we sought to determine whether Dimebon inhibited permeability transition in brain mitochondria. Dimebon reduced calcium-induced mitochondrial swelling but did not enhance the calcium retention capacity or impair calcium-induced cytochrome C release from non-synaptic mitochondria isolated from rat brain cerebral cortex. These findings indicate that Dimebon does not inhibit mitochondrial permeability transition, induced by excessive calcium uptake, in brain mitochondria. PMID:20625939

Dimebon inhibits calcium-induced swelling of rat brain mitochondria but does not alter calcium retention or cytochrome C release.

PubMed

Naga, Kranthi Kumari; Geddes, James W

2011-03-01

Dimebon was originally introduced as an antihistamine and subsequently investigated as a possible therapeutic for a variety of disorders, including Alzheimer's disease. One putative mechanism underlying the neuroprotective properties of Dimebon is inhibition of mitochondrial permeability transition, based on the observation that Dimebon inhibited the swelling of rat liver mitochondria induced by calcium and other agents that induce permeability transition. Because liver and brain mitochondria differ substantially in their properties and response to conditions associated with opening of the permeability transition pore, we sought to determine whether Dimebon inhibited permeability transition in brain mitochondria. Dimebon reduced calcium-induced mitochondrial swelling but did not enhance the calcium retention capacity or impair calcium-induced cytochrome C release from non-synaptic mitochondria isolated from rat brain cerebral cortex. These findings indicate that Dimebon does not inhibit mitochondrial permeability transition, induced by excessive calcium uptake, in brain mitochondria.

Neuronal injury-induced expression and release of apolipoprotein E in mixed neuron/glia co-cultures: nuclear factor kappaB inhibitors reduce basal and lesion-induced secretion of apolipoprotein E.

PubMed

Petegnief, V; Saura, J; de Gregorio-Rocasolano, N; Paul, S M

2001-01-01

In order to better delineate the intracellular signaling pathways underlying glial apolipoprotein E (apoE) expression and release, we have characterized an in vitro model of induction of glial apoE production induced by neuronal death. Exposure of mixed fetal cortical neuron/glia co-cultures to the neurotoxin N-methyl-D-aspartate results in increased apoE expression and release in a time- and concentration-dependent manner. Increased expression of apoE messenger RNA precedes the increase in intracellular apoE, followed by accumulation of the holoprotein in the culture medium. Neuronal injury induced by N-methyl-D-aspartate is accompanied by a reactive astrogliosis as measured by an increase in glial fibrillary acidic protein messenger RNA and protein at 48 and 72h post-lesion, respectively. A similar microgliosis was observed using the microglial marker ED-1. Neuronal injury-induced glial apoE secretion is attenuated by the nuclear factor kappaB inhibitors, aspirin, Bay 11-7082 and MG-132, suggesting that this transcription factor is involved in both constitutive and induced glial apoE expression. The present data show that up-regulation of apoE is an early event in the glial activation triggered by neurodegeneration in vitro and that activation of nuclear factor kappaB directly or indirectly mediates the increase in apoE expression.

Cytosolic acidification and intracellular zinc release in hippocampal neurons

PubMed Central

Kiedrowski, Lech

2012-01-01

In neurons exposed to glutamate, Ca2+ influx triggers intracellular Zn2+ release via an as yet unclear mechanism. Since glutamate induces a Ca2+-dependent cytosolic acidification, the present work tested the relationships among intracellular Ca2+ concentration ([Ca2+]i), intracellular pH (pHi), and [Zn2+]i. Cultured hippocampal neurons were exposed to glutamate and glycine (Glu/Gly), while [Zn2+]i, [Ca2+]i and pHi were monitored using FluoZin-3, Fura2-FF, and 2′,7′-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein, respectively. Glu/Gly applications decreased pHi to 6.1 and induced intracellular Zn2+ release in a Ca2+-dependent manner, as expected. The pHi drop reduced the affinity of FluoZin-3 and Fura-2-FF for Zn2+. The rate of Glu/Gly-induced [Zn2+]i increase was not correlated with the rate of [Ca2+]i increase. Instead, the extent of [Zn2+]i elevations corresponded well to the rate of pHi drop. Namely, [Zn2+]i increased more in more highly acidified neurons. Inhibiting the mechanisms responsible for the Ca2+-dependent pHi drop (plasmalemmal Ca2+ pump and mitochondria) counteracted the Glu/Gly-induced intracellular Zn2+ release. Alkaline pH (8.5) suppressed Glu/Gly-induced intracellular Zn2+ release whereas acidic pH (6.0) enhanced it. A pHi drop to 6.0 (without any Ca2+ influx or glutamate receptor activation) led to intracellular Zn2+ release; the released Zn2+ (free Zn2+ plus Zn2+ bound to Fura-2FF and FluoZin-3) reached 1 μM. PMID:22339672

The Release of Trapped Gases from Amorphous Solid Water Films: II. “Bottom-Up” Induced Desorption Pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, Robert A.; Smith, R. Scott; Kay, Bruce D.

2013-03-14

In this (Paper II) and the preceding companion paper (Paper I) we investigate the mechanisms for the release of trapped gases from underneath of amorphous solid water (ASW) films. In Paper I, we focused on the low coverage (pressure) regime where the release mechanism is controlled by crystallization-induced cracks formed in the ASW overlayer. In that regime the results were largely independent of the particular gas underlayer. Here in Paper II, we focus on the high coverage (pressure) regime where new desorption pathways become accessible prior to ASW crystallization. In contrast to the results for the low coverage regime (Papermore » I), the release mechanism is a function of the multilayer thickness and composition, displaying dramatically different behavior between Ar, Kr, Xe, CH4, N2, O2, and CO. Two primary desorption pathways are observed. The first occurs between 100 and 150 K and manifests itself as sharp, extremely narrow desorption peaks. Temperature programmed desorption is utilized to show that abrupt desorption bursts are due to pressure induced structural failure of the ASW overlyaer. The second pathway occurs at low temperature (typically <100 K) where broad desorption peaks are observed. Desorption through this pathway is attributed to diffusion through pores and connected pathways formed during ASW deposition. The extent of desorption and the lineshape of the low temperature desorption peak are dependent on the substrate on which the gas underlayer is deposited. Angle dependent ballistic deposition of the ASW is used vary the porosity of overlayer and confirm that the low temperature desorption pathway is due to porosity that is inherent in the ASW overlayer during deposition.« less

Cocaine-induced endocannabinoid release modulates behavioral and neurochemical sensitization in mice.

PubMed

Mereu, Maddalena; Tronci, Valeria; Chun, Lauren E; Thomas, Alexandra M; Green, Jennifer L; Katz, Jonathan L; Tanda, Gianluigi

2015-01-01

The endocannabinoid system has been implicated in the development of synaptic plasticity induced by several drugs abused by humans, including cocaine. However, there remains some debate about the involvement of cannabinoid receptors/ligands in cocaine-induced plasticity and corresponding behavioral actions. Here, we show that a single cocaine injection in Swiss-Webster mice produces behavioral and neurochemical alterations that are under the control of the endocannabinoid system. This plasticity may be the initial basis for changes in brain processes leading from recreational use of cocaine to its abuse and ultimately to dependence. Locomotor activity was monitored with photobeam cell detectors, and accumbens shell/core microdialysate dopamine levels were monitored by high-performance liquid chromatography with electrochemical detection. Development of single-trial cocaine-induced behavioral sensitization, measured as increased distance traveled in sensitized mice compared to control mice, was paralleled by a larger stimulation of extracellular dopamine levels in the core but not the shell of the nucleus accumbens. Both the behavioral and neurochemical effects were reversed by CB1 receptor blockade produced by rimonabant pre-treatments. Further, both behavioral and neurochemical cocaine sensitization were facilitated by pharmacological blockade of endocannabinoid metabolism, achieved by inhibiting the fatty acid amide hydrolase enzyme. In conclusion, our results suggest that a single unconditioned exposure to cocaine produces sensitization through neuronal alterations that require regionally specific release of endocannabinoids. Further, the present results suggest that endocannabinoids play a primary role from the earliest stage of cocaine use, mediating the inception of long-term brain-adaptive responses, shaping central pathways and likely increasing vulnerability to stimulant abuse disorders. Published 2013. This article is a U.S. Government work and is in the

Oligomeric Bax Is a Component of the Putative Cytochrome c Release Channel MAC, Mitochondrial Apoptosis-induced Channel

PubMed Central

Dejean, Laurent M.; Martinez-Caballero, Sonia; Guo, Liang; Hughes, Cynthia; Teijido, Oscar; Ducret, Thomas; Ichas, François; Korsmeyer, Stanley J.; Antonsson, Bruno; Jonas, Elizabeth A.; Kinnally, Kathleen W.

2005-01-01

Bcl-2 family proteins regulate apoptosis, in part, by controlling formation of the mitochondrial apoptosis-induced channel (MAC), which is a putative cytochrome c release channel induced early in the intrinsic apoptotic pathway. This channel activity was never observed in Bcl-2–overexpressing cells. Furthermore, MAC appears when Bax translocates to mitochondria and cytochrome c is released in cells dying by intrinsic apoptosis. Bax is a component of MAC of staurosporine-treated HeLa cells because MAC activity is immunodepleted by Bax antibodies. MAC is preferentially associated with oligomeric, not monomeric, Bax. The single channel behavior of recombinant oligomeric Bax and MAC is similar. Both channel activities are modified by cytochrome c, consistent with entrance of this protein into the pore. The mean conductance of patches of mitochondria isolated after green fluorescent protein-Bax translocation is significantly higher than those from untreated cells, consistent with onset of MAC activity. In contrast, the mean conductance of patches of mitochondria indicates MAC activity is present in apoptotic cells deficient in Bax but absent in apoptotic cells deficient in both Bax and Bak. These findings indicate Bax is a component of MAC in staurosporine-treated HeLa cells and suggest Bax and Bak are functionally redundant as components of MAC. PMID:15772159

Ethanol induces taurine release in the amygdala: an in vivo microdialysis study.

PubMed

Quertemont, E; Dahchour, A; Ward, R J; Witte, P

1999-01-01

The effect of acute IP ethanol injections on the extracellular aspartate, glutamate, taurine and GABA content of the basolateral amygdala microdialysate was investigated in relationship with total brain ethanol. Each acute intraperitoneal injection of ethanol, 0.5, 1.0, 2.0 and 3.0 g/kg body weight, induced an immediate increase in microdialysate taurine; both 0.5 and 1.0 g/kg ethanol evoked an increase during the first 20 minutes following injection which returned to baseline value by 40 minutes, despite the fact that ethanol was detectable in the brain until 60 or 120 minutes, respectively. After either 2.0 or 3.0 g/kg ethanol there was an increase in taurine of gradual intensity which gradually declined to reach baseline values by 100 minutes. In contrast, the ethanol concentration for 2.0 g/kg remained elevated at the end of the 120 minutes; approximately 25 mg ethanol/mg protein. The stimulated release of taurine within the amygdala could participate in the regulation of ethanoli-nduced changes in osmolarity, since taurine is postulated to act as an osmoregulator in the brain. Taurine could also mediate or interact with ethanol-induced central nervous system effects, as it exerts a modulatory action on cell excitability and neurotransmitter processes.

Opiate-induced dopamine release is modulated by severity of alcohol dependence: an [(18)F]fallypride positron emission tomography study.

PubMed

Spreckelmeyer, Katja N; Paulzen, Michael; Raptis, Mardjan; Baltus, Thomas; Schaffrath, Sabrina; Van Waesberghe, Julia; Zalewski, Magdalena M; Rösch, Frank; Vernaleken, Ingo; Schäfer, Wolfgang M; Gründer, Gerhard

2011-10-15

Preclinical data implicate the reinforcing effects of alcohol to be mediated by interaction between the opioid and dopamine systems of the brain. Specifically, alcohol-induced release of β-endorphins stimulates μ-opioid receptors (MORs), which is believed to cause dopamine release in the brain reward system. Individual differences in opioid or dopamine neurotransmission have been suggested to be responsible for enhanced liability to abuse alcohol. In the present study, a single dose of the MOR agonist remifentanil was administered in detoxified alcohol-dependent patients and healthy control subjects to mimic the β-endorphin-releasing properties of ethanol and to assess the effects of direct MOR stimulation on dopamine release in the mesolimbic reward system. Availability of D(2/3) receptors was assessed before and after single-dose administration of the MOR agonist remifentanil in 11 detoxified alcohol-dependent patients and 11 healthy control subjects with positron emission tomography with the radiotracer [(18)F]fallypride. Severity of dependence as assessed with the Alcohol Use Disorders Identification Test was compared with remifentanil-induced percentage change in [(18)F]fallypride binding (Δ%BP(ND)). The [(18)F]fallypride binding potentials (BP(ND)s) were significantly reduced in the ventral striatum, dorsal putamen, and amygdala after remifentanil application in both patients and control subjects. In the patient group, ventral striatum Δ%BP(ND) was correlated with the Alcohol Use Disorders Identification Test score. The data provide evidence for a MOR-mediated interaction between the opioid and the dopamine system, supporting the assumption that one way by which alcohol unfolds its rewarding effects is via a MOR-(γ-aminobutyric acid)-dopamine pathway. No difference in dopamine release was found between patients and control subjects, but evidence for a patient-specific association between sensitivity to MOR stimulation and severity of alcohol dependence

PLC-dependent intracellular Ca2+ release was associated with C6-ceramide-induced inhibition of Na+ current in rat granule cells.

PubMed

Liu, Zheng; Fei, Xiao-Wei; Fang, Yan-Jia; Shi, Wen-Jie; Zhang, Yu-Qiu; Mei, Yan-Ai

2008-09-01

In this report, the effects of C(6)-ceramide on the voltage-gated inward Na(+) currents (I(Na)), two types of main K(+) current [outward rectifier delayed K(+) current (I(K)) and outward transient K(+) current (I(A))], and cell death in cultured rat cerebellar granule cells were investigated. At concentrations of 0.01-100 microM, ceramide produced a dose-dependent and reversible inhibition of I(Na) without alteration of the steady-state activation and inactivation properties. Treatment with C(2)-ceramide caused a similar inhibitory effect on I(Na). However, dihydro-C(6)-ceramide failed to modulate I(Na). The effect of C(6)-ceramide on I(Na) was abolished by intracellular infusion of the Ca(2+)-chelating agent, 1,2-bis (2-aminophenoxy) ethane-N, N, N9, N9-tetraacetic acid, but was mimicked by application of caffeine. Blocking the release of Ca(2+) from the sarcoplasmic reticulum with ryanodine receptor blocker induced a gradual increase in I(Na) amplitude and eliminated the effect of ceramide on I(Na). In contrast, the blocker of the inositol 1,4,5-trisphosphate-sensitive Ca(2+) receptor did not affect the action of C(6)-ceramide. Intracellular application of GTPgammaS also induced a gradual decrease in I(Na) amplitude, while GDPbetaS eliminated the effect of C(6)-ceramide on I(Na). Furthermore, the C(6)-ceramide effect on I(Na) was abolished after application of the phospholipase C (PLC) blockers and was greatly reduced by the calmodulin inhibitors. Fluorescence staining showed that C(6)-ceramide decreased cell viability and blocking I(Na) by tetrodotoxin did not mimic the effect of C(6)-ceramide, and inhibiting intracellular Ca(2+) release by dantrolene could not decrease the C(6)-ceramide-induced cell death. We therefore suggest that increased PLC-dependent Ca(2+) release through the ryanodine-sensitive Ca(2+) receptor may be responsible for the C(6)-ceramide-induced inhibition of I(Na), which does not seem to be associated with C(6)-ceramide-induced granule

Prefrontal Cortex Corticotropin-Releasing Factor Receptor 1 Conveys Acute Stress-Induced Executive Dysfunction.

PubMed

Uribe-Mariño, Andrés; Gassen, Nils C; Wiesbeck, Maximilian F; Balsevich, Georgia; Santarelli, Sara; Solfrank, Beate; Dournes, Carine; Fries, Gabriel R; Masana, Merce; Labermeier, Christiana; Wang, Xiao-Dong; Hafner, Kathrin; Schmid, Bianca; Rein, Theo; Chen, Alon; Deussing, Jan M; Schmidt, Mathias V

2016-11-15

The medial prefrontal cortex (mPFC) subserves complex cognition and is impaired by stress. Corticotropin-releasing factor (CRF), through CRF receptor 1 (CRFR1), constitutes a key element of the stress response. However, its contribution to the effects of stress in the mPFC remains unclear. Mice were exposed to acute social defeat stress and subsequently to either the temporal order memory (n = 11-12) or reversal learning (n = 9-11) behavioral test. Changes in mPFC Crhr1 messenger RNA levels were measured in acutely stressed mice (n = 12). Crhr1 loxP/loxP mice received either intra-mPFC adeno-associated virus-Cre or empty microinjections (n = 17-20) and then were submitted to acute stress and later to the behavioral tests. Co-immunoprecipitation was used to detect activation of the protein kinase A (PKA) signaling pathway in the mPFC of acutely stressed mice (n = 8) or intra-mPFC CRF injected mice (n = 7). Finally, mice received intra-mPFC CRF (n = 11) and/or Rp-isomer cyclic adenosine 3',5' monophosphorothioate (Rp-cAMPS) (n = 12) microinjections and underwent behavioral testing. We report acute stress-induced effects on mPFC-mediated cognition, identify CRF-CRFR1-containing microcircuits within the mPFC, and demonstrate stress-induced changes in Crhr1 messenger RNA expression. Importantly, intra-mPFC CRFR1 deletion abolishes acute stress-induced executive dysfunction, whereas intra-mPFC CRF mimics acute stress-induced mPFC dysfunction. Acute stress and intra-mPFC CRF activate the PKA signaling pathway in the mPFC, leading to cyclic AMP response element binding protein phosphorylation in intra-mPFC CRFR1-expressing neurons. Finally, PKA blockade reverses the intra-mPFC CRF-induced executive dysfunction. Taken together, these results unravel a molecular mechanism linking acute stress to executive dysfunction via CRFR1. This will aid in the development of novel therapeutic targets for stress-induced cognitive dysfunction. Copyright © 2016 Society of Biological

Antiprogestin-releasing intrauterine devices

PubMed Central

Nayak, NR; Slayden, OD; Mah, K; Chwalisz, K; Brenner, Robert M

2007-01-01

Intrauterine devices (IUDs) that release progestins are highly effective contraceptives, but they induce breakthrough bleeding that some women find unacceptable. Because progesterone (P) antagonists (AP) are known to suppress the endometrium, induce amenorrhea, and inhibit fertility, AP IUDs may provide an effective contraceptive that also controls endometrial bleeding. Here we assessed the effects of empty (blank) vs AP-releasing (ZK 230 211) IUDs on bleeding patterns and endometrial growth in ovariectomized, artificially cycled macaques. The AP IUDs (but not the blank controls) induced extended, frank menstruation when inserted during the late luteal phase, an indication of local AP action. Over time, endometrial glandular and arterial proliferation were inhibited, steroid receptors were elevated, spiral arteries showed degenerative changes, progesterone withdrawal bleeding was prevented and estradiol-dependent proliferation was suppressed by the AP IUDs. In sum, AP IUDs suppressed the effects of P on endometrial progestational development and blocked the effects of estradiol on endometrial proliferation as previously shown for systemic treatment with APs. Therefore, AP IUDs may provide novel contraceptive devices with minimal breakthrough bleeding. PMID:17531599

Investigation of factors affecting in vitro doxorubicin release from PEGylated liposomal doxorubicin for the development of in vitro release testing conditions.

PubMed

Shibata, Hiroko; Izutsu, Ken-Ichi; Yomota, Chikako; Okuda, Haruhiro; Goda, Yukihiro

2015-01-01

Establishing appropriate drug release testing methods of liposomal products for assuring quality and performance requires the determination of factors affecting in vitro drug release. In this study, we investigated the effects of test conditions (human plasma lot, pH/salt concentration in the test media, dilution factor, temperature, ultrasound irradiation, etc.), and liposomal preparation conditions (pH/concentration of ammonium sulfate solution), on doxorubicin (DXR) release from PEGylated liposomal DXR. Higher temperature and lower pH significantly increased DXR release. The evaluation of DXR solubility indicated that the high DXR release induced by low pH may be attributed to the high solubility of DXR at low pH. Ultrasound irradiation induced rapid DXR release in an amplitude-dependent manner. The salt concentration in the test solution, human plasma lot, and dilution factor had a limited impact on DXR-release. Variations in the ammonium sulfate concentration used in solutions for the formation/hydration of liposomes significantly affected DXR release behavior, whereas differences in pH did not. In addition, heating condition in phosphate-buffered saline at lower pH (<6.5) exhibited higher discriminative ability for the release profiles from various liposomes with different concentrations of ammonium sulfate than did ultrasound irradiation. These results are expected to be helpful in the process of establishing appropriate drug release testing methods for PEGylated liposomal DXR.

DDPH ameliorated oxygen and glucose deprivation-induced injury in rat hippocampal neurons via interrupting Ca2+ overload and glutamate release.

PubMed

He, Zhi; Lu, Qing; Xu, Xulin; Huang, Lin; Chen, Jianguo; Guo, Lianjun

2009-01-28

Our previous work has demonstrated that DDPH (1-(2, 6-dimethylphenoxy)-2-(3, 4-dimethoxyphenylethylamino) propane hydrochloride), a competitive alpha(1)-adrenoceptor antagonist, could improve cognitive deficits, reduce histopathological damage and facilitate synaptic plasticity in vivo possibly via increasing NR2B (NMDA receptor 2B) expression and antioxidation of DDPH itself. The present study further evaluated effects of DDPH on OGD (Oxygen and glucose deprivation)-induced neuronal damage in rat primary hippocampal cells. The addition of DDPH to the cultured cells 12 h before OGD for 4 h significantly reduced neuronal damage as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and LDH (lactate dehydrogenase) release experiments. The effects of DDPH on intracellular calcium concentration were explored by Fura-2 based calcium imaging techniques and results showed that DDPH at the dosages of 5 microM and 10 microM suppressed the increase of intracellular calcium ([Ca(2+)](i)) stimulated by 50 mM KCl in Ca(2+)-containing extracellular solutions. However, DDPH couldn't suppress the increase of [Ca(2+)](i) induced by both 50 microM glutamate in Ca(2+)-containing extracellular solutions and 20 microM ATP (Adenosine Triphosphate) in Ca(2+)-free solution. These results indicated that DDPH prevented [Ca(2+)](i) overload in hippocampal neurons by blocking Ca(2+) influx (voltage-dependent calcium channel) but not Ca(2+) mobilization from the intracellular Ca(2+) store in endoplasm reticulum (ER). We also demonstrated that DDPH could decrease glutamate release when hippocampal cells were subjected to OGD. These observations demonstrated that DDPH protected hippocampal neurons against OGD-induced damage by preventing the Ca(2+) influx and decreasing glutamate release.

Synthesis and characterization of superabsorbent polymer prepared by radiation-induced graft copolymerization of acrylamide onto carboxymethyl cellulose for controlled release of agrochemicals

NASA Astrophysics Data System (ADS)

Hemvichian, Kasinee; Chanthawong, Auraruk; Suwanmala, Phiriyatorn

2014-10-01

Superabsorbent polymer (SAP) was synthesized by radiation-induced grafting of acrylamide (AM) onto carboxymethyl cellulose (CMC) in the presence of a crosslinking agent, N,N‧-methylenebisacrylamide (MBA). The effects of various parameters, such as dose, the amount of CMC, AM, MBA and ionic strength on the swelling ratio were investigated. In order to evaluate its controlled release potential, SAP was loaded with potassium nitrate (KNO3) as an agrochemical model and its potential for controlled release of KNO3 was studied. The amount of released KNO3 was analyzed by an inductively coupled plasma mass spectrometry (ICP-MS). The results from controlled release experiment agreed very well with the results from swelling experiment. The synthesized SAP was characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The obtained SAP exhibited a swelling ratio of 190 g/g of dry gel.

Cocaine cue-induced dopamine release in amygdala and hippocampus: a high-resolution PET [¹⁸F]fallypride study in cocaine dependent participants.

PubMed

Fotros, Aryandokht; Casey, Kevin F; Larcher, Kevin; Verhaeghe, Jeroen A J; Cox, Sylvia M L; Gravel, Paul; Reader, Andrew J; Dagher, Alain; Benkelfat, Chawki; Leyton, Marco

2013-08-01

Drug-related cues are potent triggers for relapse in people with cocaine dependence. Dopamine (DA) release within a limbic network of striatum, amygdala and hippocampus has been implicated in animal studies, but in humans it has only been possible to measure effects in the striatum. The objective here was to measure drug cue-induced DA release in the amygdala and hippocampus using high-resolution PET with [(18)F]fallypride. Twelve cocaine-dependent volunteers (mean age: 39.6 ± 8.0 years; years of cocaine use: 15.9 ± 7.4) underwent two [(18)F]fallypride high-resolution research tomography-PET scans, one with exposure to neutral cues and one with cocaine cues. [(18)F]Fallypride non-displaceable-binding potential (BPND) values were derived for five regions of interest (ROI; amygdala, hippocampus, ventral limbic striatum, associative striatum, and sensorimotor striatum). Subjective responses to the cues were measured with visual analog scales and grouped using principal component analysis. Drug cue exposure significantly decreased BPND values in all five ROI in subjects who had a high-, but not low-, craving response (limbic striatum: p=0.019, associative striatum: p=0.008, sensorimotor striatum: p=0.004, amygdala: p=0.040, and right hippocampus: p=0.025). Individual differences in the cue-induced craving response predicted the magnitude of [(18)F]fallypride responses within the striatum (ventral limbic: r=0.581, p=0.048; associative: r=0.589, p=0.044; sensorimotor: r=0.675, p=0.016). To our knowledge this study provides the first evidence of drug cue-induced DA release in the amygdala and hippocampus in humans. The preferential induction of DA release among high-craving responders suggests that these aspects of the limbic reward network might contribute to drug-seeking behavior.

Delta-9-Tetrahydrocannabinol-Induced Dopamine Release as a Function of Psychosis Risk: 18F-Fallypride Positron Emission Tomography Study

PubMed Central

Kuepper, Rebecca; Ceccarini, Jenny; Lataster, Johan; van Os, Jim; van Kroonenburgh, Marinus; van Gerven, Joop M. A.; Marcelis, Machteld; Van Laere, Koen; Henquet, Cécile

2013-01-01

Cannabis use is associated with psychosis, particularly in those with expression of, or vulnerability for, psychotic illness. The biological underpinnings of these differential associations, however, remain largely unknown. We used Positron Emission Tomography and 18F-fallypride to test the hypothesis that genetic risk for psychosis is expressed by differential induction of dopamine release by Δ9-THC (delta-9-tetrahydrocannabinol, the main psychoactive ingredient of cannabis). In a single dynamic PET scanning session, striatal dopamine release after pulmonary administration of Δ9-THC was measured in 9 healthy cannabis users (average risk psychotic disorder), 8 patients with psychotic disorder (high risk psychotic disorder) and 7 un-related first-degree relatives (intermediate risk psychotic disorder). PET data were analyzed applying the linear extension of the simplified reference region model (LSRRM), which accounts for time-dependent changes in 18F-fallypride displacement. Voxel-based statistical maps, representing specific D2/3 binding changes, were computed to localize areas with increased ligand displacement after Δ9-THC administration, reflecting dopamine release. While Δ9-THC was not associated with dopamine release in the control group, significant ligand displacement induced by Δ9-THC in striatal subregions, indicative of dopamine release, was detected in both patients and relatives. This was most pronounced in caudate nucleus. This is the first study to demonstrate differential sensitivity to Δ9-THC in terms of increased endogenous dopamine release in individuals at risk for psychosis. PMID:23936196

A leukocyte activation test identifies food items which induce release of DNA by innate immune peripheral blood leucocytes.

PubMed

Garcia-Martinez, Irma; Weiss, Theresa R; Yousaf, Muhammad N; Ali, Ather; Mehal, Wajahat Z

2018-01-01

Leukocyte activation (LA) testing identifies food items that induce a patient specific cellular response in the immune system, and has recently been shown in a randomized double blinded prospective study to reduce symptoms in patients with irritable bowel syndrome (IBS). We hypothesized that test reactivity to particular food items, and the systemic immune response initiated by these food items, is due to the release of cellular DNA from blood immune cells. We tested this by quantifying total DNA concentration in the cellular supernatant of immune cells exposed to positive and negative foods from 20 healthy volunteers. To establish if the DNA release by positive samples is a specific phenomenon, we quantified myeloperoxidase (MPO) in cellular supernatants. We further assessed if a particular immune cell population (neutrophils, eosinophils, and basophils) was activated by the positive food items by flow cytometry analysis. To identify the signaling pathways that are required for DNA release we tested if specific inhibitors of key signaling pathways could block DNA release. Foods with a positive LA test result gave a higher supernatant DNA content when compared to foods with a negative result. This was specific as MPO levels were not increased by foods with a positive LA test. Protein kinase C (PKC) inhibitors resulted in inhibition of positive food stimulated DNA release. Positive foods resulted in CD63 levels greater than negative foods in eosinophils in 76.5% of tests. LA test identifies food items that result in release of DNA and activation of peripheral blood innate immune cells in a PKC dependent manner, suggesting that this LA test identifies food items that result in release of inflammatory markers and activation of innate immune cells. This may be the basis for the improvement in symptoms in IBS patients who followed an LA test guided diet.

Natural Killer (NK)/melanoma cell interaction induces NK-mediated release of chemotactic High Mobility Group Box-1 (HMGB1) capable of amplifying NK cell recruitment

PubMed Central

Parodi, Monica; Pedrazzi, Marco; Cantoni, Claudia; Averna, Monica; Patrone, Mauro; Cavaletto, Maria; Spertino, Stefano; Pende, Daniela; Balsamo, Mirna; Pietra, Gabriella; Sivori, Simona; Carlomagno, Simona; Mingari, Maria Cristina; Moretta, Lorenzo; Sparatore, Bianca; Vitale, Massimo

2015-01-01

In this study we characterize a new mechanism by which Natural Killer (NK) cells may amplify their recruitment to tumors. We show that NK cells, upon interaction with melanoma cells, can release a chemotactic form of High Mobility Group Box-1 (HMGB1) protein capable of attracting additional activated NK cells. We first demonstrate that the engagement of different activating NK cell receptors, including those mainly involved in tumor cell recognition can induce the active release of HMGB1. Then we show that during NK-mediated tumor cell killing two HMGB1 forms are released, each displaying a specific electrophoretic mobility possibly corresponding to a different redox status. By the comparison of normal and perforin-defective NK cells (which are unable to kill target cells) we demonstrate that, in NK/melanoma cell co-cultures, NK cells specifically release an HMGB1 form that acts as chemoattractant, while dying tumor cells passively release a non-chemotactic HMGB1. Finally, we show that Receptor for Advanced Glycation End products is expressed by NK cells and mediates HMGB1-induced NK cell chemotaxis. Proteomic analysis of NK cells exposed to recombinant HMGB1 revealed that this molecule, besides inducing immediate chemotaxis, also promotes changes in the expression of proteins involved in the regulation of the cytoskeletal network. Importantly, these modifications could be associated with an increased motility of NK cells. Thus, our findings allow the definition of a previously unidentified mechanism used by NK cells to amplify their response to tumors, and provide additional clues for the emerging role of HMGB1 in immunomodulation and tumor immunity. PMID:26587323

Vasoactive intestinal polypeptide provokes acetylcholine release from the myenteric plexus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusunoki, M.; Tsai, L.H.; Taniyama, K.

1986-07-01

Effects of vasoactive intestinal polypeptide (VIP) on the release of acetylcholine (ACh) from longitudinal muscle strips with myenteric plexus (LM) preparations were examined in the guinea pig small intestine. VIP (10 to 10 W M) induced a concentration-dependent contraction of LM preparation. The VIP-induced contractions seem to be related to three components, the scopolamine-sensitive, the scopolamine-insensitive, the tetrodotoxin-sensitive, and the tetrodotoxin-insensitive contractions. VIP (10 to 10 W M) induced a concentration-dependent increase in the release of (TH)ACh from LM preparations preloaded with (TH)choline. The VIP-evoked (TH)ACh release was inhibited by removal of CaS from the perfusion medium and by treatmentmore » with tetrodotoxin but not by scopolamine and hexamethonium. The spontaneous and VIP-evoked (TH)ACh release was not affected by phentolamine, propranolol, methysergide, diphenhydramine, cimetidine, bicuculline, or (D-ProS, D-Trp/sup 7,9/)substance P. The result demonstrates that VIP induces contractions of longitudinal smooth muscle directly and indirectly by the stimulation of both cholinergic neurons and noncholinergic excitatory neurons.« less

Synergistic effect of sunlight induced photothermal conversion and H2O2 release based on hybridized tungsten oxide gel for cancer inhibition

NASA Astrophysics Data System (ADS)

Wang, Cong; Gao, Yibo; Gao, Xinghua; Wang, Hua; Tian, Jingxuan; Wang, Li; Zhou, Bingpu; Ye, Ziran; Wan, Jun; Wen, Weijia

2016-10-01

A highly efficient photochromic hydrogel was successfully fabricated via casting precursor, which is based on amorphous tungsten oxide and poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide). Under simulated solar illumination, the hydrogel has a rapid and controlled temperature increasing ratio as its coloration degree. Localized electrons in the amorphous tungsten oxide play a vital role in absorption over a broad range of wavelengths from 400 nm to 1100 nm, encompassing the entire visible light and infrared regions in the solar spectrum. More importantly, the material exhibits sustainable released H2O2 induced by localized electrons, which has a synergistic effect with the rapid surface temperature increase. The amount of H2O2 released by each film can be tuned by the light irradiation, and the film coloration can indicate the degree of oxidative stress. The ability of the H2O2-releasing gels in vitro study was investigated to induce apoptosis in melanoma tumor cells and NIH 3T3 fibroblasts. The in vivo experimental results indicate that these gels have a greater healing effect than the control in the early stages of tumor formation.

Synergistic effect of sunlight induced photothermal conversion and H2O2 release based on hybridized tungsten oxide gel for cancer inhibition

PubMed Central

Wang, Cong; Gao, Yibo; Gao, Xinghua; Wang, Hua; Tian, Jingxuan; Wang, Li; Zhou, Bingpu; Ye, Ziran; Wan, Jun; Wen, Weijia

2016-01-01

A highly efficient photochromic hydrogel was successfully fabricated via casting precursor, which is based on amorphous tungsten oxide and poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide). Under simulated solar illumination, the hydrogel has a rapid and controlled temperature increasing ratio as its coloration degree. Localized electrons in the amorphous tungsten oxide play a vital role in absorption over a broad range of wavelengths from 400 nm to 1100 nm, encompassing the entire visible light and infrared regions in the solar spectrum. More importantly, the material exhibits sustainable released H2O2 induced by localized electrons, which has a synergistic effect with the rapid surface temperature increase. The amount of H2O2 released by each film can be tuned by the light irradiation, and the film coloration can indicate the degree of oxidative stress. The ability of the H2O2-releasing gels in vitro study was investigated to induce apoptosis in melanoma tumor cells and NIH 3T3 fibroblasts. The in vivo experimental results indicate that these gels have a greater healing effect than the control in the early stages of tumor formation. PMID:27775086

DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway

PubMed Central

Cervantes, Christopher; Liu, Juan; He, Sijia; Zhou, Haiyan; Zhang, Bilin; Cai, Huan; Yin, Dongqing; Hu, Derong; Li, Zhi; Chen, Hongzhi; Gao, Xiaoli; Wang, Fang; O’Connor, Jason C.; Xu, Yong; Liu, Meilian; Dong, Lily Q.

2017-01-01

Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the DNA-sensing cGAS-cGAMP-STING pathway. Fat-specific knockout of disulfide-bond A oxidoreductase-like protein (DsbA-L), a chaperone-like protein originally identified in the mitochondrial matrix, impaired mitochondrial function and promoted mtDNA release, leading to activation of the cGAS-cGAMP-STING pathway and inflammatory responses. Conversely, fat-specific overexpression of DsbA-L protected mice against high-fat diet-induced activation of the cGAS-cGAMP-STING pathway and inflammation. Taken together, we identify DsbA-L as a key molecule that maintains mitochondrial integrity. DsbA-L deficiency promotes inflammation and insulin resistance by activating the cGAS-cGAMP-STING pathway. Our study also reveals that, in addition to its well-characterized roles in innate immune surveillance, the cGAS-cGAMP-STING pathway plays an important role in mediating obesity-induced metabolic dysfunction. PMID:29087318

DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway.

PubMed

Bai, Juli; Cervantes, Christopher; Liu, Juan; He, Sijia; Zhou, Haiyan; Zhang, Bilin; Cai, Huan; Yin, Dongqing; Hu, Derong; Li, Zhi; Chen, Hongzhi; Gao, Xiaoli; Wang, Fang; O'Connor, Jason C; Xu, Yong; Liu, Meilian; Dong, Lily Q; Liu, Feng

2017-11-14

Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the DNA-sensing cGAS-cGAMP-STING pathway. Fat-specific knockout of disulfide-bond A oxidoreductase-like protein (DsbA-L), a chaperone-like protein originally identified in the mitochondrial matrix, impaired mitochondrial function and promoted mtDNA release, leading to activation of the cGAS-cGAMP-STING pathway and inflammatory responses. Conversely, fat-specific overexpression of DsbA-L protected mice against high-fat diet-induced activation of the cGAS-cGAMP-STING pathway and inflammation. Taken together, we identify DsbA-L as a key molecule that maintains mitochondrial integrity. DsbA-L deficiency promotes inflammation and insulin resistance by activating the cGAS-cGAMP-STING pathway. Our study also reveals that, in addition to its well-characterized roles in innate immune surveillance, the cGAS-cGAMP-STING pathway plays an important role in mediating obesity-induced metabolic dysfunction.

Inhibition of Calpains Protects Mn-Induced Neurotransmitter release disorders in Synaptosomes from Mice: Involvement of SNARE Complex and Synaptic Vesicle Fusion.

PubMed

Wang, Can; Xu, Bin; Ma, Zhuo; Liu, Chang; Deng, Yu; Liu, Wei; Xu, Zhao-Fa

2017-06-16

Overexposure to manganese (Mn) could disrupt neurotransmitter release via influencing the formation of SNARE complex, but the underlying mechanisms are still unclear. A previous study demonstrated that SNAP-25 is one of substrate of calpains. The current study investigated whether calpains were involved in Mn-induced disorder of SNARE complex. After mice were treated with Mn for 24 days, Mn deposition increased significantly in basal nuclei in Mn-treated and calpeptin pre-treated groups. Behaviorally, less time spent in the center of the area and decreased average velocity significantly in an open field test after 24 days of Mn exposure. With the increase in MnCl 2 dosage, intracellular Ca 2+ increased significantly, but pretreatment with calpeptin caused a dose-dependent decrease in calpains activity. There were fragments of N-terminal of SNAP-25 protein appearance in Mn-treated groups, but it is decreased with pretreatment of calpeptin. FM1-43-labeled synaptic vesicles also provided evidence that the treatment with Mn resulted in increasing first and then decreasing, which was consistent with Glu release and the 80 kDa protein levels of SNARE complexes. In summary, Mn induced the disorder of neurotransmitter release through influencing the formation of SNARE complex via cleaving SNAP-25 by overactivation of calpains in vivo.

[Slow-release recombinant human bone morphogenetic protein-2 suppresses chromium wear particle-induced osteolysis in rats].

PubMed

Li, Gan; Li, Qi; Lin, Li-Jun; Duan, Xin; Zhang, Xi-Qi

2012-03-01

To observe the effect of a slow-release recombinant human bone morphogenetic protein-2 (rhBMP-2) formulation on the expressions of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in a murine air pouch model of bone implantation. A cranial bone allograft was implanted in the air pouch induced on the back of the recipients. The rat models were then randomized into 5 groups, including a blank control group, chromium particle group, and 3 rhBMP-2 groups receiving 50, 100 or 200 µg/L slow-release rhBMP-2 in addition to chromium particles. Three weeks later, the expressions of RANKL and OPG in the air pouch was detected using Western blotting and RT-PCR, and the positively stained area for osteoclasts in the bone graft was determined with TRAP staining for drug effect assessment. RANKL and OPG expressions were found in the air pouches in all the 5 groups. RANKL and OPG protein and mRNA expressions, RANKL/OPG ratio and osteoclast staining area in the bone graft were the highest in chromium particle group (P<0.05), but were significantly decreased by treatment with the slow-release rhBMP-2 formulation (P<0.05); the measurements showed no significant differences between the blank control group and 200 µg/L rhBMP-2 group (P>0.05). Chromium particles can cause osteolysis by increasing the RANKL/OPG ratio in rats, and intervention with slow-release rhBMP-2 can significantly promote bone formation and suppress bone resorption by decreasing RANKL/OPG ratio.

Cold urticaria: inhibition of cold-induced histamine release by doxantrazole.

PubMed

Bentley-Phillips, C B; Eady, R A; Greaves, M W

1978-10-01

Thirteen patients with cold urticaria were studied to assess the effect of the systemic drug doxantrazole, which has actions resembling disodium cromoglycate, on cold evoked histamine release. The patients, all of whom developed an immediate local whealing response after cooling of the forearm, demonstrated release of histamine into venous blood draining that forearm. Following doxantrazole treatment, significant suppression of histamine release occurred. In some but not all patients this was accompanied by diminution of urtication in response to cooling. A double-blind study was carried out in 3 subjects, all of whom showed diminished cold-stimulated histamine release after doxantrazole. Two of these showed clinical improvement. Doxantrazole had no effect on erythema due to intradermal histamine, but did suppress the erythematous reaction to intradermal injection of compound 48/80. Our results suggest that doxantrazole or related anti-allergic agents might be useful in the treatment of cold urticaria.

Ca2+ release triggered by nicotinate adenine dinucleotide phosphate in intact sea urchin eggs.

PubMed Central

Perez-Terzic, C M; Chini, E N; Shen, S S; Dousa, T P; Clapham, D E

1995-01-01

Nicotinate adenine dinucleotide phosphate (NAADP) was recently identified [Lee and Aarhus (1995) J. Biol. Chem. 270, 2152-2157; Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] as a potent Ca(2+)-releasing agent in sea urchin egg homogenates. NAADP triggered Ca2+ release by a mechanism that was distinct from inositol 1,4,5-trisphosphate (InsP3)- and cyclic ADP-ribose (cADPR)-induced Ca2+ release. When NAADP was microinjected into intact sea urchin eggs it induced a dose-dependent increase in cytoplasmic free Ca2+ which was independent of the extracellular [Ca2+]. The Ca2+ waves elicited by microinjections of NAADP originated at the site of injection and swept across the cytosol. As previously found in sea urchin egg homogenates, NAADP-induced Ca2+ release in intact eggs was not blocked by heparin or by prior desensitization to InsP3 or cADPR. Thio-NADP, a specific inhibitor of the NAADP-induced Ca2+ release in sea urchin homogenates [Chini, Beers and Dousa (1995) J. Biol. Chem. 270, 3116-3223] blocked NAADP (but not InsP3 or cADPR) injection-induced Ca2+ release in intact sea urchin eggs. Finally, fertilization of sea urchin eggs abrogated subsequent NAADP-induced Ca2+ release, suggesting that the NAADP-sensitive Ca2+ pool may participate in the fertilization response. This study demonstrates that NAADP acts as a selective Ca(2+)-releasing agonist in intact cells. Images Figure 2 PMID:8554544

Effects of luteinizing hormone-releasing hormone and arginine-vasotocin on the sperm-release response of Günther's Toadlet, Pseudophryne guentheri

PubMed Central

2010-01-01

Background Luteinizing hormone-releasing hormone (LHRH) is an exogenous hormone commonly used to induce spermiation in anuran amphibians. Over the past few decades, the LHRH dose administered to individuals and the frequency of injection has been highly variable. The sperm-release responses reported have been correspondingly diverse, highlighting a need to quantify dose-response relationships on a species-specific basis. This study on the Australian anuran Pseudophryne guentheri first evaluated the spermiation response of males administered one of five LHRHa doses, and second, determined whether AVT administered in combination with the optimal LHRHa dose improved sperm-release. Methods Male toadlets were administered a single dose of 0, 1, 2, 4 or 8 micrograms/g body weight of LHRHa. A 4 micrograms/g dose of AVT was administered alone or in combination with 2 micrograms/g LHRHa. Spermiation responses were evaluated at 3, 7 and 12 h post hormone administration (PA), and sperm number and viability were quantified using fluorescent microscopy. Results LHRHa administration was highly effective at inducing spermiation in P. guentheri, with 100% of hormone-treated males producing sperm during the experimental period. The number of sperm released in response to 2 micrograms/g LHRHa was greater than all other doses administered and sperm viability was highest in the 1 microgram/g treatment. The administration of AVT alone or in combination with LHRHa resulted in the release of significantly lower sperm numbers. Conclusion Overall, results from this study suggest that in P. guentheri, LHRHa is effective at inducing spermiation, but that AVT inhibits sperm-release. PMID:21059269

Involvement of P-type Ca2+ channels in the K(+)- and d-fenfluramine-induced [3H]5-HT release from rat hippocampal synaptosomes.

PubMed

Frittoli, E; Gobbi, M; Mennini, T

1994-06-01

The Ca2(+)-dependent [3H]5-HT release induced by depolarization or by 0.5 microM d-fenfluramine in rat hippocampal synaptosomes, was significantly reduced (35-42%) by three different P-type Ca2+ channels blockers (omega-Agatoxin-IVA, 100 nM, funnel-web spider toxin, FTX, 0.05 microliters/ml, and its synthetic analogue, sFTX, 1 mM), indicating the major role of these channels in the Ca2+ influx preceding neurotransmitter release.

Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

PubMed

Mann, Rajinder S; Ali, Jared G; Hermann, Sara L; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S; Alborn, Hans T; Stelinski, Lukasz L

2012-01-01

Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace

Effect of Leu-enkephalin and delta sleep inducing peptide (DSIP) on endogenous noradrenaline release by rat brain synaptosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lozhanets, V.V.; Anosov, A.K.

1986-01-01

The nonapeptide delta-sleep inducing peptide (DSIP) causes specific changes in the encephalogram of recipient animals: It prolongs the phase of long-wave or delta sleep. The cellular mechanism of action of DSIP has not yet been explained. To test the hyporhesis that this peptide or its degradation product may be presynaptic regulators of catecholamine release, the action of Leu-enkephaline, DSIP, and amino acids composing DSIP on release of endogenous noradrenalin (NA) from synaptosomes during depolarization was compared. Subcellular fractions from cerebral hemisphere of noninbred male albino rats were isolated. Lactate dehydrogenase activity was determined in the suspension of synaptosomes before andmore » after addition of 0.5% Triton X-100. The results were subjected to statistical analysis, using the Wilcoxon-Mann-Whitney nonparametric test.« less

Human Dermal Mast Cells Contain and Release Tumor Necrosis Factor α, which Induces Endothelial Leukocyte Adhesion Molecule 1

NASA Astrophysics Data System (ADS)

Walsh, Laurence J.; Trinchieri, Giorgio; Waldorf, Heidi A.; Whitaker, Diana; Murphy, George F.

1991-05-01

Tumor necrosis factor α (TNF-α) is a proinflammatory cytokine that mediates endothelial leukocyte interactions by inducing expression of adhesion molecules. In this report, we demonstrate that human dermal mast cells contain sizeable stores of immunoreactive and biologically active TNF-α within granules, which can be released rapidly into the extracellular space upon degranulation. Among normal human dermal cells, mast cells are the predominant cell type that expresses both TNF-α protein and TNF-α mRNA. Moreover, induction of endothelial leukocyte adhesion molecule 1 expression is a direct consequence of release of mast cell-derived TNF-α. These findings establish a role for human mast cells as "gatekeepers" of the dermal microvasculature and indicate that mast cell products other than vasoactive amines influence endothelium in a proinflammatory fashion.

Intracellular NAD+ levels are associated with LPS-induced TNF-α release in pro-inflammatory macrophages

PubMed Central

Al-Shabany, Abbas Jawad; Moody, Alan John; Foey, Andrew David; Billington, Richard Andrew

2016-01-01

Metabolism and immune responses have been shown to be closely linked and as our understanding increases, so do the intricacies of the level of linkage. NAD+ has previously been shown to regulate tumour necrosis factor-α (TNF-α) synthesis and TNF-α has been shown to regulate NAD+ homoeostasis providing a link between a pro-inflammatory response and redox status. In the present study, we have used THP-1 differentiation into pro- (M1-like) and anti- (M2-like) inflammatory macrophage subset models to investigate this link further. Pro- and anti-inflammatory macrophages showed different resting NAD+ levels and expression levels of NAD+ homoeostasis enzymes. Challenge with bacterial lipopolysaccharide, a pro-inflammatory stimulus for macrophages, caused a large, biphasic and transient increase in NAD+ levels in pro- but not anti-inflammatory macrophages that were correlated with TNF-α release and inhibition of certain NAD+ synthesis pathways blocked TNF-α release. Lipopolysaccharide stimulation also caused changes in mRNA levels of some NAD+ homoeostasis enzymes in M1-like cells. Surprisingly, despite M2-like cells not releasing TNF-α or changing NAD+ levels in response to lipopolysaccharide, they showed similar mRNA changes compared with M1-like cells. These data further strengthen the link between pro-inflammatory responses in macrophages and NAD+. The agonist-induced rise in NAD+ shows striking parallels to well-known second messengers and raises the possibility that NAD+ is acting in a similar manner in this model. PMID:26764408

Bladder pain induced by prolonged peripheral alpha 1A adrenoceptor stimulation involves the enhancement of transient receptor potential vanilloid 1 activity and an increase of urothelial adenosine triphosphate release.

PubMed

Matos, R; Cordeiro, J M; Coelho, A; Ferreira, S; Silva, C; Igawa, Y; Cruz, F; Charrua, A

2016-12-01

Pathophysiological mechanisms of chronic visceral pain (CVP) are unknown. This study explores the association between the sympathetic system and bladder nociceptors activity by testing the effect of a prolonged adrenergic stimulation on transient receptor potential vanilloid 1 (TRPV1) activity and on urothelial adenosine triphosphate (ATP) release. Female Wistar rats received saline, phenylephrine (PHE), PHE + silodosin, PHE + naftopidil or PHE + prazosin. TRPV1 knockout and wild-type mice received saline or PHE. Visceral pain behaviour tests were performed before and after treatment. Cystometry was performed, during saline and capsaicin infusion. Fos immunoreactivity was assessed in L6 spinal cord segment. Human urothelial ATP release induced by mechanical and thermal stimulation was evaluated. Subcutaneous, but not intrathecal, PHE administration induced pain, which was reversed by silodosin, a selective alpha 1A adrenoceptor antagonist, but not by naftopidil, a relatively selective antagonist for alpha 1D adrenoceptor. Silodosin also reversed PHE-induced bladder hyperactivity and L6 spinal cord Fos expression. Thus, in subsequent experiments, only silodosin was used. Wild-type, but not TRPV1 knockout, mice exhibited phenylephrine-induced pain. Capsaicin induced a greater increase in voiding contractions in PHE-treated rats than in control animals, and silodosin reversed this effect. When treated with PHE, ATP release from human urothelial cells was enhanced either by mechanical stimulation or by lowering the thermal threshold of urothelial TRPV1, which becomes abnormally responsive at body temperature. This study suggests that the activation of peripheral alpha 1A adrenoceptors induces CVP, probably through its interaction with TRPV1 and ATP release. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Influence of exercise on NA- and Hsp72-induced release of IFNγ by the peritoneal suspension of macrophages and lymphocytes from genetically obese Zucker rats.

PubMed

Martín-Cordero, L; García, J J; Hinchado, M D; Bote, E; Ortega, E

2013-03-01

Regular physical exercise is recognized as a nonpharmacological therapeutic strategy in the treatment of metabolic syndrome, and has been proposed for improving obesity, diabetic status, insulin resistance, and immune response. The aim of the present study was to evaluate the effect of a regular exercise program (treadmill running, 5 days/week for 14 weeks at 35 cm/s for 35 min in the last month) on the release of the pro-inflammatory cytokine interferon gamma (IFNγ) by peritoneal cells (macrophages and lymphocytes) from obese Zucker rats (fa/fa) in response to noradrenaline (NA) and heat shock proteins of 72 kDa (Hsp72), and the possible adaptation due to training for a bout acute exercise (a single session of 25-35 min at 35 cm/s). In healthy (lean Fa/fa) and obese animals, peritoneal cells released greater concentrations of IFNγ in response to Hsp72 and lower concentrations in response to NA. The regular exercise training protocol, evaluated in the obese animals, produced a clear change in the regulation of the release of IFNγ. Peritoneal immune cells from trained animals released more IFNγ in response to NA, but there was a reduction in the release of IFNγ in response to Hsp72. In the obese animals, regular exercise caused a change in the inhibitory effect of NA (which now becomes stimulatory) and the stimulatory effect of Hsp72e (which now becomes inhibitory) in relation to the release of IFNγ. This reflects that Hsp72, induced by the prior release of NA following exercise-induced stress, plays a role in the homeostatic balance of release of IFNγ by peritoneal immune cells in obese animals during exercise.

Renal epithelial cells can release ATP by vesicular fusion

PubMed Central

Bjaelde, Randi G.; Arnadottir, Sigrid S.; Overgaard, Morten T.; Leipziger, Jens; Praetorius, Helle A.

2013-01-01

Renal epithelial cells have the ability to release nucleotides as paracrine factors. In the intercalated cells of the collecting duct, ATP is released by connexin30 (cx30), which is selectively expressed in this cell type. However, ATP is released by virtually all renal epithelia and the aim of the present study was to identify possible alternative nucleotide release pathways in a renal epithelial cell model. We used MDCK (type1) cells to screen for various potential ATP release pathways. In these cells, inhibition of the vesicular H+-ATPases (bafilomycin) reduced both the spontaneous and hypotonically (80%)-induced nucleotide release. Interference with vesicular fusion using N-ethylamide markedly reduced the spontaneous nucleotide release, as did interference with trafficking from the endoplasmic reticulum to the Golgi apparatus (brefeldin A1) and vesicular transport (nocodazole). These findings were substantiated using a siRNA directed against SNAP-23, which significantly reduced spontaneous ATP release. Inhibition of pannexin and connexins did not affect the spontaneous ATP release in this cell type, which consists of ~90% principal cells. TIRF-microscopy of either fluorescently-labeled ATP (MANT-ATP) or quinacrine-loaded vesicles, revealed that spontaneous release of single vesicles could be promoted by either hypoosmolality (50%) or ionomycin. This vesicular release decreased the overall cellular fluorescence by 5.8 and 7.6% respectively. In summary, this study supports the notion that spontaneous and induced ATP release can occur via exocytosis in renal epithelial cells. PMID:24065923

Activation of Spinal μ- and δ-Opioid Receptors Potently Inhibits Substance P Release Induced by Peripheral Noxious Stimuli

PubMed Central

Beaudry, Hélène; Dubois, Dave; Gendron, Louis

2013-01-01

Over the past few years, δ-opioid receptors (DOPRs) and μ-opioid receptors (MOPRs) have been shown to interact with each other. We have previously seen that expression of MOPR is essential for morphine and inflammation to potentiate the analgesic properties of selective DOPR agonists. In vivo, it is not clear whether MOPRs and DOPRs are expressed in the same neurons. Indeed, it was recently proposed that these receptors are segregated in different populations of nociceptors, with MOPRs and DOPRs expressed by peptidergic and nonpeptidergic fibers, respectively. In the present study, the role and the effects of DOPR- and MOPR-selective agonists in two different pain models were compared. Using preprotachykinin A knock-out mice, we first confirmed that substance P partly mediates intraplantar formalin- and capsaicin-induced pain behaviors. These mice had a significant reduction in pain behavior compared with wild-type mice. We then measured the effects of intrathecal deltorphin II (DOPR agonist) and DAMGO (MOPR agonist) on pain-like behavior, neuronal activation, and substance P release following formalin and capsaicin injection. We found that both agonists were able to decrease formalin- and capsaicin-induced pain, an effect that was correlated with a reduction in the number of c-fos-positive neurons in the superficial laminae of the lumbar spinal cord. Finally, visualization of NK1 (neurokinin 1) receptor internalization revealed that DOPR and MOPR activation strongly reduced formalin- and capsaicin-induced substance P release via direct action on primary afferent fibers. Together, our results indicate that functional MOPRs and DOPRs are both expressed by peptidergic nociceptors. PMID:21917790

Carbon Monoxide (CO) Released from Tricarbonyldichlororuthenium (II) Dimer (CORM-2) in Gastroprotection against Experimental Ethanol-Induced Gastric Damage.

PubMed

Magierowska, Katarzyna; Magierowski, Marcin; Hubalewska-Mazgaj, Magdalena; Adamski, Juliusz; Surmiak, Marcin; Sliwowski, Zbigniew; Kwiecien, Slawomir; Brzozowski, Tomasz

2015-01-01

The physiological gaseous molecule, carbon monoxide (CO) becomes a subject of extensive investigation due to its vasoactive activity throughout the body but its role in gastroprotection has been little investigated. We determined the mechanism of CO released from its donor tricarbonyldichlororuthenium (II) dimer (CORM-2) in protection of gastric mucosa against 75% ethanol-induced injury. Rats were pretreated with CORM-2 30 min prior to 75% ethanol with or without 1) non-selective (indomethacin) or selective cyclooxygenase (COX)-1 (SC-560) and COX-2 (celecoxib) inhibitors, 2) nitric oxide (NO) synthase inhibitor L-NNA, 3) ODQ, a soluble guanylyl cyclase (sGC) inhibitor, hemin, a heme oxygenase (HO)-1 inductor or zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1 activity. The CO content in gastric mucosa and carboxyhemoglobin (COHb) level in blood was analyzed by gas chromatography. The gastric mucosal mRNA expression for HO-1, COX-1, COX-2, iNOS, IL-4, IL-1β was analyzed by real-time PCR while HO-1, HO-2 and Nrf2 protein expression was determined by Western Blot. Pretreatment with CORM-2 (0.5-10 mg/kg) dose-dependently attenuated ethanol-induced lesions and raised gastric blood flow (GBF) but large dose of 100 mg/kg was ineffective. CORM-2 (5 mg/kg and 50 mg/kg i.g.) significantly increased gastric mucosal CO content and whole blood COHb level. CORM-2-induced protection was reversed by indomethacin, SC-560 and significantly attenuated by celecoxib, ODQ and L-NNA. Hemin significantly reduced ethanol damage and raised GBF while ZnPPIX which exacerbated ethanol-induced injury inhibited CORM-2- and hemin-induced gastroprotection and the accompanying rise in GBF. CORM-2 significantly increased gastric mucosal HO-1 mRNA expression and decreased mRNA expression for iNOS, IL-1β, COX-1 and COX-2 but failed to affect HO-1 and Nrf2 protein expression decreased by ethanol. We conclude that CORM-2 released CO exerts gastroprotection against ethanol-induced gastric lesions

The oncolytic peptide LTX-315 induces cell death and DAMP release by mitochondria distortion in human melanoma cells

PubMed Central

Eike, Liv-Marie; Yang, Nannan; Rekdal, Øystein; Sveinbjørnsson, Baldur

2015-01-01

Host defense peptides (HDPs) are naturally occurring molecules found in most species, in which they play a significant role in the first line defense against intruding pathogens, and several HDPs have been shown to possess anticancer activity. Structure-activity relationship studies on the HDP bovine lactoferricin revealed a de novo design of a nonamer peptide LTX-315, with oncolytic properties. In the present study, we investigated the oncolytic activity of LTX-315 in human melanoma cells (A375). LTX-315 induced a rapid plasma membrane disruption and cell death within 2 hours. At a low concentration, fluorescence-labeled LTX-315 was internalized and accumulated in cytoplasmic vacuoles in close proximity to the mitochondria. The mitochondrial membrane potential was shown to depolarize as a consequence of LTX-315 treatment and at ultrastructural level, the mitochondria morphology was significantly altered. Release of danger signals (DAMPs) such as ATP, Cytochrome C and HMGB1 into the cell supernatant of cultured cells was evident minutes after peptide treatment. The oncolytic effect of LTX-315 involving perturbation of both the cell membrane and the mitochondria with subsequent release of DAMPs may highlight the ability of LTX-315 to induce complete regression and long-term protective immune responses as previously reported in experimental animal models. PMID:26472184

Blood banking-induced alteration of red blood cell oxygen release ability

PubMed Central

Li, Yaojin; Xiong, Yanlian; Wang, Ruofeng; Tang, Fuzhou; Wang, Xiang

2016-01-01

Background Current blood banking procedures may not fully preserve red blood cell (RBC) function during storage, contributing to the decrease of RBC oxygen release ability. This study was undertaken to evaluate the impact of routine cold storage on RBC oxygen release ability. Materials and methods RBC units were collected from healthy donors and each unit was split into two parts (whole blood and suspended RBC) to exclude possible donor variability. Oxygen dissociation measurements were performed on blood units stored at 4 °C during a 5-week period. 2,3-diphosphoglycerate levels and fluorescent micrographs of erythrocyte band 3 were also analysed. Results P50 and oxygen release capacity decreased rapidly during the first 3 weeks, and then did not change significantly. In contrast, the kinetic properties (PO2-t curve and T*50) of oxygen release changed slowly during the first 3 weeks of storage, but then decreased significantly in the last 2 weeks. 2,3-diphosphoglycerate decreased quickly during the first 3 weeks of storage to almost undetectable levels. Band 3 aggregated significantly during the last 2 weeks of storage. Discussion RBC oxygen release ability appears to be sensitive to routine cold storage. The thermodynamic characteristics of RBC oxygen release ability changed mainly in the first 3 weeks of storage, due to the decrease of 2,3-diphosphoglycerate, whereas the kinetic characteristics of RBC oxygen release ability decreased significantly at the end of storage, probably affected by alterations of band 3. PMID:26674824

Blood banking-induced alteration of red blood cell oxygen release ability.

PubMed

Li, Yaojin; Xiong, Yanlian; Wang, Ruofeng; Tang, Fuzhou; Wang, Xiang

2016-05-01

Current blood banking procedures may not fully preserve red blood cell (RBC) function during storage, contributing to the decrease of RBC oxygen release ability. This study was undertaken to evaluate the impact of routine cold storage on RBC oxygen release ability. RBC units were collected from healthy donors and each unit was split into two parts (whole blood and suspended RBC) to exclude possible donor variability. Oxygen dissociation measurements were performed on blood units stored at 4 °C during a 5-week period. 2,3-diphosphoglycerate levels and fluorescent micrographs of erythrocyte band 3 were also analysed. P50 and oxygen release capacity decreased rapidly during the first 3 weeks, and then did not change significantly. In contrast, the kinetic properties (PO2-t curve and T*50) of oxygen release changed slowly during the first 3 weeks of storage, but then decreased significantly in the last 2 weeks. 2,3-diphosphoglycerate decreased quickly during the first 3 weeks of storage to almost undetectable levels. Band 3 aggregated significantly during the last 2 weeks of storage. RBC oxygen release ability appears to be sensitive to routine cold storage. The thermodynamic characteristics of RBC oxygen release ability changed mainly in the first 3 weeks of storage, due to the decrease of 2,3-diphosphoglycerate, whereas the kinetic characteristics of RBC oxygen release ability decreased significantly at the end of storage, probably affected by alterations of band 3.

Intracellular Calcium Mobilization in Response to Ion Channel Regulators via a Calcium-Induced Calcium Release Mechanism

PubMed Central

Petrou, Terry; Olsen, Hervør L.; Thrasivoulou, Christopher; Masters, John R.; Ashmore, Jonathan F.

2017-01-01

Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been used to treat a range of human diseases, on [Ca2+]i release, by ratiometric calcium imaging. We show that six such modulators [amiodarone (Ami), dofetilide, furosemide (Fur), minoxidil (Min), loxapine (Lox), and Nicorandil] initiate release of [Ca2+]i in prostate and breast cancer cell lines, PC3 and MCF7, respectively. Whole-cell currents in PC3 cells were inhibited by the compounds tested in patch-clamp experiments in a concentration-dependent manner. In all cases [Ca2+]i was increased by modulator concentrations comparable to those used clinically. The increase in [Ca2+]i in response to Ami, Fur, Lox, and Min was reduced significantly (P < 0.01) when the external calcium was reduced to nM concentration by chelation with EGTA. The data suggest that many ion channel regulators mobilize [Ca2+]i. We suggest a mechanism whereby calcium-induced calcium release is implicated; such a mechanism may be important for understanding the action of these compounds. PMID:27980039

AGE/RAGE-Induced EMP Release via the NOX-Derived ROS Pathway.

PubMed

Chen, Ying-Hua; Chen, Zhang-Wei; Li, Hong-Mei; Yan, Xin-Feng; Feng, Bo

2018-01-01

Diabetes is associated with accelerated formation of advanced glycation end products (AGEs) that are extensively found in circulating endothelial microparticles (EMPs). This study aimed to investigate whether AGEs have a direct effect on EMP formation and the possible underlying mechanism. In vitro, cultured human umbilical vein endothelial cells (HUVECs) were incubated with AGEs (200 and 400  μ g/ml) for 24 hours with or without pretreatment with anti-RAGE antibody, NOX inhibitor, or ROS scavenger. The number of CD31-positive EMPs was assessed by flow cytometry. The number of EMPs was significantly increased in HUVECs stimulated by AGEs in a dose-dependent manner. In addition, receptors for AGEs (RAGE), NAD(P)H oxidase (NOX), and reactive oxygen species (ROS) were increased by AGEs as compared to the control group. These changes could be reversed when HUVECs were pretreated with anti-RAGE antibody. Moreover, inhibition of NOX as well as antioxidant treatment reduced the release of EMPs induced by AGEs. Our study suggested that AGEs increased EMP generation, which was mediated by RAGE signaling through NOX-derived ROS.

Enhancement of bradykinin and resensitization of its B2 receptor.

PubMed

Marcic, B; Deddish, P A; Jackman, H L; Erdös, E G

1999-03-01

We studied the enhancement of the effects of bradykinin B2 receptor agonists by agents that react with active centers of angiotensin-converting enzyme (ACE) independent of enzymatic inactivation. The potentiation and the desensitization and resensitization of B2 receptor were assessed by measuring [3H]arachidonic acid release and [Ca2+]i mobilization in Chinese hamster ovary cells transfected to express human ACE and B2 receptor, or in endothelial cells with constitutively expressed ACE and receptor. Administration of bradykinin or its ACE-resistant analogue desensitized the receptor, but it was resensitized (arachidonic acid release or [Ca2+]i mobilization) by agents such as enalaprilat (1 micromol/L). Enalaprilat was inactive in the absence of ACE expression. La3+ (100 micromol/L) inhibited the apparent resensitization, probably by blocking the entry of extracellular calcium. Enalaprilat resensitized the receptor via ACE to release arachidonic acid by bradykinin at a lower concentration (5 nmol/L) than required to mobilize [Ca2+]i (1 micromol/L). Monoclonal antibodies inhibiting the ACE N-domain active center and polyclonal antiserum potentiated bradykinin. The snake venom peptide BPP5a and metabolites of angiotensin and bradykinin (angiotensin-[1-9], angiotensin-[1-7], bradykinin-[1-8]; 1 micromol/L) enhanced arachidonic acid release by bradykinin. Angiotensin-(1-9) and -(1-7) also resensitized the receptor. Enalaprilat potentiated the bradykinin effect in cells expressing a mutant ACE with a single N-domain active site. Agents that reacted with a single active site, on the N-domain or on the C-domain, potentiated bradykinin not by blocking its inactivation but by inducing crosstalk between ACE and the receptor. Enalaprilat enhanced signaling via ACE by Galphai in lower concentration than by Galphaq-coupled receptor.

The Food Contaminants Nivalenol and Deoxynivalenol Induce Inflammation in Intestinal Epithelial Cells by Regulating Reactive Oxygen Species Release.

PubMed

Adesso, Simona; Autore, Giuseppina; Quaroni, Andrea; Popolo, Ada; Severino, Lorella; Marzocco, Stefania

2017-12-11

Fusarium mycotoxins are fungal metabolites whose ability to affect cereal grains as multi-contaminants is progressively increasing. The trichothecene mycotoxins nivalenol (NIV) and deoxynivalenol (DON) are often found in almost all agricultural commodities worldwide. They are able to affect animal and human health, including at the intestinal level. In this study, NIV, both alone and in combination with DON, induced inflammation and increased the inflammatory response induced by lipopolysaccharide (LPS) plus Interferon-γ (IFN) in the non-tumorigenic intestinal epithelial cell line (IEC-6). The inflammatory response induced by NIV and DON involves tumor necrosis factor-α (TNF-α) production, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, nitrotyrosine formation, reactive oxygen species (ROS) release, Nuclear Factor-κB (NF-κB), Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and inflammasome activation. The pro-inflammatory effect was strongly induced by NIV and by the mycotoxin mixture, when compared to DON alone. Mechanistic studies indicate a pivotal role for ROS in the observed pro-inflammatory effects induced by mycotoxins. In this study, the interactions between NIV and DON point out the importance of their food co-contamination, further highlighting the risk assessment process that is of growing concern.

Role of p38 MAPK in the selective release of IL-8 induced by chemical allergen in naive THp-1 cells.

PubMed

Mitjans, Montserrat; Viviani, Barbara; Lucchi, Laura; Galli, Corrado L; Marinovich, Marina; Corsini, Emanuela

2008-03-01

At present, the assessment of the allergenic potential of chemicals is carried out using animal models. Over the last decade, several in vitro methods mainly using primary dendritic cells have been proposed to identify the potential of chemicals to induce skin sensitization to meet current animal welfare and public opinions. The major limitations of such tests are the donor-to-donor variability, the low levels in the source, and a possible shortage of human sources. The aim of the present investigation was to establish an in vitro test to identify chemical allergens using the human promyelocytic cell line THP-1 in order to avoid some of these difficulties. We investigated whether the chemokine interleukin-8 or CXCL8 (IL-8) production could provide a methodology for the detection of both respiratory and contact allergens. THP-1 cells were exposed to contact allergens (cinnamaldehyde, dinitrochlorobenzene, nickel sulfate, penicillin G, p-phenylenediamine, tetramethylthiuram disulfide), to respiratory allergens (ammonium hexachloroplatinate, diphenylmethane diisocyanate, trimellitic anhydride) and to irritants (salicylic acid, phenol, sodium lauryl sulphate). Following 48 h of incubation, the release of IL-8 was evaluated by sandwich ELISA. IL-8 production was significantly increased after stimulation with all allergens tested, with the exception of trimellitic anhydride, whereas irritants exposure failed to induce IL-8 release. The lack of IL-8 production by trimellitic anhydride can be explained by the rapid hydrolysis of this chemical in water to trimellitic acid, which is not an allergen. In contrast to IL-8 release, CD54 and CD86 expression did not provide a sensitive method failing to correctly identify approximately 30% of the tested compounds. Although CD86 appears to be a more sensitive marker than CD54 when discriminating allergens from irritants neither of these markers provided robust methodology. We also investigated if a common activation pathway in

Transient Anosmia Induces Depressive-like and Anxiolytic-like Behavior and Reduces Amygdalar Corticotropin-Releasing Hormone in a ZnSO4-Induced Mouse Model.

PubMed

Ahn, Sangzin; Choi, Mooseok; Kim, Hyunju; Yang, Eun-Jeong; Mahmood, Usman; Kang, Seong-Il; Shin, Hyun-Woo; Kim, Dae Woo; Kim, Hye-Sun

2018-04-23

Olfactory loss is known to affect both mood and quality of life. Transient anosmia was induced in mice to study the resulting changes in mood, behavior, and on a molecular level. Transient anosmia was induced by a single intranasal instillation of ZnSO4 in BALB/c mice. Hematoxylin and eosin (HE) staining, and potato chip finding test were performed to confirm olfactory loss. Tail suspension, forced swim, and splash tests were performed to evaluate depression-related behavior; while the open field, and elevated plus maze tests were used to evaluate anxiety-related behavior. The mRNA levels of amygdalar corticotropin-releasing hormone (CRH) and hypothalamic glucocorticoid receptor (GR) were quantified using real-time PCR to confirm relevant molecular change. Olfactory loss was confirmed 1-2.5 weeks after induction, and this loss was subsequently reversed over time. The results of the behavioral tests indicated increased depression-like and reduced anxiety-like behavior at week 1. Accordingly, PCR data identified decreased amygdalar CRH expression at week 1. These results suggest that transient anosmia induces both depressive and anxiolytic behavior as a result of decreased amygdalar CRH in a mouse model of anosmia.

N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Byeong Mo; Choi, Yun Jung; Han, Youngsoo

2009-08-15

N,N-dimethyl phytosphingosine (DMPS) blocks the conversion of sphingosine to sphingosine-1-phosphate (S1P) by the enzyme sphingosine kinase (SK). In this study, we elucidated the apoptotic mechanisms of DMPS action on a human leukemia cell line using functional pharmacologic and genetic approaches. First, we demonstrated that DMPS-induced apoptosis is evidenced by nuclear morphological change, distinct internucleosomal DNA fragmentation, and an increased sub-G1 cell population. DMPS treatment led to the activation of caspase-9 and caspase-3, accompanied by the cleavage of poly(ADP-ribose) polymerase (PARP) and led to cytochrome c release, depolarization of the mitochondrial membrane potential, and downregulation of the anti-apoptotic members of themore » bcl-2 family. Ectopic expression of bcl-2 and bcl-xL conferred resistance of HL-60 cells to DMPS-induced cell death, suggesting that DMPS-induced apoptosis occurs predominantly through the activation of the intrinsic mitochondrial pathway. We also observed that DMPS activated the caspase-8-Bid-Bax pathway and that the inhibition of caspase-8 by z-IETD-fmk or small interfering RNA suppressed the cleavage of Bid, cytochrome c release, caspase-3 activation, and apoptotic cell death. In addition, cells subjected to DMPS exhibited significantly increased reactive oxygen species (ROS) generation, and ROS scavengers, such as quercetin and Tiron, but not N-acetylcysteine (NAC), inhibited DMPS-induced activations of caspase-8, -3 and subsequent apoptotic cell death, indicating the role of ROS in caspase-8-mediated apoptosis. Taken together, these results indicate that caspase-8 acts upstream of caspase-3, and that the caspase-8-mediated mitochondrial pathway is important in DMPS-induced apoptosis. Our results also suggest that ROS are critical regulators of caspase-8-mediated apoptosis in DMPS-treated leukemia cells.« less

CD38 Mediates Angiotensin II–Induced Intracellular Ca2+ Release in Rat Pulmonary Arterial Smooth Muscle Cells

PubMed Central

Lee, Suengwon; Paudel, Omkar; Jiang, Yongliang; Yang, Xiao-Ru

2015-01-01

CD38 is a multifunctional enzyme that catalyzes the formation of the endogenous Ca2+-mobilizing messengers cyclic ADP-ribose (cADPR) and nicotinic acid adenosine dinucleotide phosphate (NAADP) for the activation of ryanodine receptors (RyRs) of sarcoplasmic reticulum and NAADP-sensitive Ca2+ release channels in endolysosomes, respectively. It plays important roles in systemic vascular functions, but there is little information on CD38 in pulmonary arterial smooth muscle cells (PASMCs). Earlier studies suggested a redox-sensing role of CD38 in hypoxic pulmonary vasoconstriction. This study sought to characterize its roles in angiotensin II (Ang II)–induced Ca2+ release (AICR) in PASMCs. Examination of CD38 expression in various rat arteries found high levels of CD38 mRNA and protein in pulmonary arteries. The Ang II–elicited Ca2+ response consisted of extracellular Ca2+ influx and intracellular Ca2+ release in PASMCs. AICR activated in the absence of extracellular Ca2+ was reduced by pharmacological or siRNA inhibition of CD38, by the cADPR antagonist 8-bromo-cADPR or ryanodine, and by the NAADP antagonist Ned-19 or disruption of endolysosomal Ca2+ stores with the vacuolar H+-ATPase inhibitor bafilomycin A1. Suppression of AICR by the inhibitions of cADPR- and NAADP-dependent pathways were nonadditive, indicating interdependence of RyR- and NAADP-gated Ca2+ release. Furthermore, AICR was inhibited by the protein kinase C inhibitor staurosporine, the nonspecific NADPH oxidase (NOX) inhibitors apocynin and diphenyleneiodonium, the NOX2-specific inhibitor gp91ds-tat, and the scavenger of reactive oxygen species (ROS) tempol. These results provide the first evidence that Ang II activates CD38-dependent Ca2+ release via the NOX2-ROS pathway in PASMCs. PMID:25078456

Correlation of individual differences in schizotypal personality traits with amphetamine-induced dopamine release in striatal and extrastriatal brain regions.

PubMed

Woodward, Neil D; Cowan, Ronald L; Park, Sohee; Ansari, M Sib; Baldwin, Ronald M; Li, Rui; Doop, Mikisha; Kessler, Robert M; Zald, David H

2011-04-01

Schizotypal personality traits are associated with schizophrenia spectrum disorders, and individuals with schizophrenia spectrum disorders demonstrate increased dopamine transmission in the striatum. The authors sought to determine whether individual differences in normal variation in schizotypal traits are correlated with dopamine transmission in the striatum and in extrastriatal brain regions. Sixty-three healthy volunteers with no history of psychiatric illness completed the Schizotypal Personality Questionnaire and underwent positron emission tomography imaging with [(18)F]fallypride at baseline and after administration of oral d-amphetamine (0.43 mg/kg). Dopamine release, quantified by subtracting each participant's d-amphetamine scan from his or her baseline scan, was correlated with Schizotypal Personality Questionnaire total and factor scores using region-of-interest and voxel-wise analyses. Dopamine release in the striatum was positively correlated with overall schizotypal traits. The association was especially robust in the associative subdivision of the striatum. Voxel-wise analyses identified additional correlations between dopamine release and schizotypal traits in the left middle frontal gyrus and left supramarginal gyrus. Exploratory analyses of Schizotypal Personality Questionnaire factor scores revealed correlations between dopamine release and disorganized schizotypal traits in the striatum, thalamus, medial prefrontal cortex, temporal lobe, insula, and inferior frontal cortex. The association between dopamine signaling and psychosis phenotypes extends to individual differences in normal variation in schizotypal traits and involves dopamine transmission in both striatal and extrastriatal brain regions. Amphetamine-induced dopamine release may be a useful endophenotype for investigating the genetic basis of schizophrenia spectrum disorders.

Altered elementary calcium release events and enhanced calcium release by thymol in rat skeletal muscle.

PubMed

Szentesi, Péter; Szappanos, Henrietta; Szegedi, Csaba; Gönczi, Monika; Jona, István; Cseri, Julianna; Kovács, László; Csernoch, László

2004-03-01

The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine binding to heavy sarcoplasmic reticulum vesicles, with a half-activating concentration of 144 micro M and a Hill coefficient of 1.89, and the open probability of the isolated and reconstituted ryanodine receptors, from 0.09 +/- 0.03 to 0.22 +/- 0.04 at 30 micro M. At higher concentrations the drug induced long-lasting open events on a full conducting state. Elementary calcium release events imaged using laser scanning confocal microscopy in the line-scan mode were reduced in size, 0.92 +/- 0.01 vs. 0.70 +/- 0.01, but increased in duration, 56 +/- 1 vs. 79 +/- 1 ms, by 30 micro M thymol, with an increase in the relative proportion of lone embers. Higher concentrations favored long events, resembling embers in control, with duration often exceeding 500 ms. These findings provide direct experimental evidence that the opening of a single release channel will generate an ember, rather than a spark, in mammalian skeletal muscle.

A diels-alder modulated approach to control and sustain the release of dexamethasone and induce osteogenic differentiation of human mesenchymal stem cells

PubMed Central

Koehler, Kenneth C.; Alge, Daniel L.; Anseth, Kristi S.; Bowman, Christopher N.

2013-01-01

We report a new approach to controlled drug release based upon exploiting the dynamic equilibrium that exists between Diels-Alder reactants and products, demonstrating the release of a furan containing dexamethasone peptide (dex-KGPQG-furan) from a maleimide containing hydrogel. Using a reaction-diffusion model, the release kinetics were tuned to achieve sustained concentrations conducive to osteogenic differentiation of human mesenchymal stem cells (hMSCs). Efficacy was first demonstrated in a 2D culture model, in which dexamethasone release induced significant increases in alkaline phosphatase (ALP) activity and mineral deposition in hMSCs compared to a dexamethasone-free treatment. The results were similar to that observed with a soluble dexamethasone treatment. More dramatic differences were observed in 3D culture, where co-encapsulation of a dexamethasone releasing hydrogel depot within an hMSC-laden extracellular matrix mimetic poly(ethylene glycol) hydrogel resulted in a local and robust osteogenic differentiation. ALP activity reached levels that were up to six times higher than the dexamethasone free treatment. Interestingly, at 5 and 10 day time points, the ALP activity exceeded the dexamethasone positive control, suggesting a potential benefit of sustained release in 3D culture. After 21 days, substantial mineralization comparable to the positive control was also observed in the hydrogels. Collectively, these results demonstrate Diels-Alder modulated release as an effective and versatile new platform for controlled drug delivery that may prove especially beneficial for sustaining the release of low molecular weight molecules in hydrogel systems. PMID:23465826

New trends in combined use of gonadotropin-releasing hormone antagonists with gonadotropins or pulsatile gonadotropin-releasing hormone in ovulation induction and assisted reproductive technologies.

PubMed

Gordon, K; Danforth, D R; Williams, R F; Hodgen, G D

1992-10-01

The use of gonadotropin-releasing hormone agonists as adjunctive therapy with gonadotropins for ovulation induction in in vitro fertilization and other assisted reproductive technologies has become common clinical practice. With the recent advent of potent gonadotropin-releasing hormone antagonists free from the marked histamine-release effects that stymied earlier compounds, an attractive alternative method may be available. We have established the feasibility of combining gonadotropin-releasing hormone antagonist-induced inhibition of endogenous gonadotropins with exogenous gonadotropin therapy for ovulation induction in a nonhuman primate model. Here, the principal benefits to be gained from using the gonadotropin-releasing hormone antagonist rather than the gonadotropin-releasing hormone agonist are the immediate inhibition of pituitary gonadotropin secretion without the "flare effect," which brings greater safety and convenience for patients and the medical team and saves time and money. We have also recently demonstrated the feasibility of combining gonadotropin-releasing hormone antagonist with pulsatile gonadotropin-releasing hormone therapy for the controlled restoration of gonadotropin secretion and gonadal steroidogenesis culminating in apparently normal (singleton) ovulatory cycles. This is feasible only with gonadotropin-releasing hormone antagonists because, unlike gonadotropin-releasing hormone agonists, they achieve control of the pituitary-ovarian axis without down regulation of the gonadotropin-releasing hormone receptor system. This capacity to override gonadotropin-releasing hormone antagonist-induced suppression of pituitary-ovarian function may allow new treatment modalities to be employed for women who suffer from chronic hyperandrogenemia with polycystic ovarian disease.

Bone formation in vivo induced by Cbfa1-carrying adenoviral vectors released from a biodegradable porous β-tricalcium phosphate (β-TCP) material.

PubMed

Uemura, Toshimasa; Kojima, Hiroko

2011-06-01

Overexpression of Cbfa1 (a transcription factor indispensable for osteoblastic differentiation) is expected to induce the formation of bone directly and indirectly in vivo by accelerating osteoblastic differentiation. Adenoviral vectors carrying the cDNA of Cbfa1/til-1(Adv-Cbf1) were allowed to be adsorbed onto porous blocks of β-tricalcium phosphate (β-TCP), a biodegradable ceramic, which were then implanted subcutaneously and orthotopically into bone defects. The adenoviral vectors were released sustainingly by biodegradation, providing long-term expression of the genes. Results of the subcutaneous implantation of Adv-Cbfa1-adsorbed β-TCP/osteoprogenitor cells suggest that a larger amount of bone formed in the pores of the implant than in the control material. Regarding orthotopic implantation into bone defects, the released Adv-Cbfa1 accelerated regeneration in the cortical bone, whereas it induced bone resorption in the marrow cavity. A safer gene transfer using a smaller amount of the vector was achieved using biodegradable porous β-TCP as a carrier.

Bone formation in vivo induced by Cbfa1-carrying adenoviral vectors released from a biodegradable porous β-tricalcium phosphate (β-TCP) material

NASA Astrophysics Data System (ADS)

Uemura, Toshimasa; Kojima, Hiroko

2011-06-01

Overexpression of Cbfa1 (a transcription factor indispensable for osteoblastic differentiation) is expected to induce the formation of bone directly and indirectly in vivo by accelerating osteoblastic differentiation. Adenoviral vectors carrying the cDNA of Cbfa1/til-1(Adv-Cbf1) were allowed to be adsorbed onto porous blocks of β-tricalcium phosphate (β-TCP), a biodegradable ceramic, which were then implanted subcutaneously and orthotopically into bone defects. The adenoviral vectors were released sustainingly by biodegradation, providing long-term expression of the genes. Results of the subcutaneous implantation of Adv-Cbfa1-adsorbed β-TCP/osteoprogenitor cells suggest that a larger amount of bone formed in the pores of the implant than in the control material. Regarding orthotopic implantation into bone defects, the released Adv-Cbfa1 accelerated regeneration in the cortical bone, whereas it induced bone resorption in the marrow cavity. A safer gene transfer using a smaller amount of the vector was achieved using biodegradable porous β-TCP as a carrier.

PLC-beta2 monitors the drug-induced release of differentiation blockade in tumoral myeloid precursors.

PubMed

Brugnoli, Federica; Bovolenta, Matteo; Benedusi, Mascia; Miscia, Sebastianó; Capitani, Silvano; Bertagnolo, Valeria

2006-05-01

The differentiation therapy in treatment of acute promyelocytic leukemia (APL), based on the administration of all-trans retinoic acid (ATRA), is currently flanked with the use of As2O3, a safe and effective agent for patients showing a resistance to ATRA treatment. A synergy between ATRA and As3O3 was also reported in inducing granulocytic differentiation of APL-derived cells. We have demonstrated that phospholipase C-beta2 (PLC-beta2), highly expressed in neutrophils and nearly absent in tumoral promyelocytes, largely increases during ATRA treatment of APL-derived cells and strongly correlates with the responsiveness of APL patients to ATRA-based differentiating therapies. Here we report that, in APL-derived cells, low doses of As3O3 induce a slight increase of PLC-beta2 together with a moderate maturation, and cooperate with ATRA to provoke a significant increase of PLC-beta2 expression. Remarkably, the amounts of PLC-beta2 draw a parallel with the differentiation levels reached by both ATRA-responsive and -resistant cells treated with ATRA/As2O3 combinations. PLC-beta2 is not necessary for the progression of tumoral promyelocytes along the granulocytic lineage and is unable to overcome the differentiation block or to potentiate the agonist-induced maturation. On the other hand, since its expression closely correlates with the differentiation level reached by APL-derived cells induced to maturate by drugs presently employed in APL therapies, PLC-beta2 represents indeed a specific marker to test the ability of differentiation agents to induce the release of the maturation blockade of tumoral myeloid precursors.

Gastrin-releasing peptide induces monocyte adhesion to vascular endothelium by upregulating endothelial adhesion molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Mi-Kyoung; Park, Hyun-Joo; Department of Dental Pharmacology, BK21 PLUS Project, School of Dentistry, Pusan National University, Yangsan 626-870

Gastrin-releasing peptide (GRP) is a neuropeptide that plays roles in various pathophysiological conditions including inflammatory diseases in peripheral tissues; however, little is known about whether GRP can directly regulate endothelial inflammatory processes. In this study, we showed that GRP promotes the adhesion of leukocytes to human umbilical vein endothelial cells (HUVECs) and the aortic endothelium. GRP increased the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by activating nuclear factor-κB (NF-κB) in endothelial cells. In addition, GRP activated extracellular signal-regulated kinase 1/2 (ERK1/2), p38MAPK, and AKT, and the inhibition of these signaling pathways significantly reduced GRP-inducedmore » monocyte adhesion to the endothelium. Overall, our results suggested that GRP may cause endothelial dysfunction, which could be of particular relevance in the development of vascular inflammatory disorders. - Highlights: • GRP induces adhesion of monocytes to vascular endothelium. • GRP increases the expression of endothelial adhesion molecules through the activation of NF-κB. • ERK1/2, p38MAPK, and Akt pathways are involved in the GRP-induced leukocyte adhesiveness to endothelium.« less

Ghrelin receptor antagonism attenuates cocaine- and amphetamine-induced locomotor stimulation, accumbal dopamine release, and conditioned place preference.

PubMed

Jerlhag, Elisabet; Egecioglu, Emil; Dickson, Suzanne L; Engel, Jörgen A

2010-09-01

Recently we demonstrated that genetic or pharmacological suppression of the central ghrelin signaling system, involving the growth hormone secretagogue receptor 1A (GHS-R1A), lead to a reduced reward profile from alcohol. As the target circuits for ghrelin in the brain include a mesolimbic reward pathway that is intimately associated with reward-seeking behaviour, we sought to determine whether the central ghrelin signaling system is required for reward from drugs of abuse other than alcohol, namely cocaine or amphetamine. We found that amphetamine-as well as cocaine-induced locomotor stimulation and accumbal dopamine release were reduced in mice treated with a GHS-R1A antagonist. Moreover, the ability of these drugs to condition a place preference was also attenuated by the GHS-R1A antagonist. Thus GHS-R1A appears to be required not only for alcohol-induced reward, but also for reward induced by psychostimulant drugs. Our data suggest that the central ghrelin signaling system constitutes a novel potential target for treatment of addictive behaviours such as drug dependence.

Induced Release of a Plant-Defense Volatile ‘Deceptively’ Attracts Insect Vectors to Plants Infected with a Bacterial Pathogen

PubMed Central

Mann, Rajinder S.; Ali, Jared G.; Hermann, Sara L.; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S.; Alborn, Hans T.; Stelinski, Lukasz L.

2012-01-01

Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace

ACh-induced endothelial NO synthase translocation, NO release and vasodilatation in the hamster microcirculation in vivo

PubMed Central

Figueroa, Xavier F; González, Daniel R; Martínez, Agustín D; Durán, Walter N; Boric, Mauricio P

2002-01-01

Studies in cultured cells show that activation of endothelial nitric oxide (NO) synthase (eNOS) requires the dissociation of this enzyme from its inhibitory association with caveolin-1 (Cav-1), and perhaps its translocation from plasma membrane caveolae to other cellular compartments. We investigated the hypothesis that in vivo NO-dependent vasodilatation is associated with the translocation of eNOS from the cell membrane. To this end, we applied ACh topically (10-100 μm for 10 min) to the hamster cheek pouch microcirculation and measured NO production, blood flow and vessel diameter, and assessed subcellular eNOS distribution by Western blotting. Baseline NO production was 54.4 ± 5.2 pmol min−1 (n = 16). ACh increased NO release, caused arteriolar and venular dilatation and elevated microvascular flow. These responses were inhibited by NG-nitro-L-arginine (30 μm). The maximal increase in NO production induced by 10 μm and 100 μm ACh was 45 ± 20 % and 111 ± 33 %, respectively; the corresponding blood flow increases were 50 ± 10 % and 130 ± 24 %, respectively (n = 4-6). Both responses followed a similar time course, although increases in NO preceded flow changes. In non-stimulated tissues, eNOS was distributed mainly in the microsomal fraction. ACh-induced vasodilatation was associated with eNOS translocation to the cytosolic and Golgi-enriched fractions. After 1.5, 3.0 or 6.0 min of application, 10 μm ACh decreased the level of membrane-bound eNOS by -13 ± 4 %, -60 ± 4 % and -19 ± 17 %, respectively; at the same time points, 100 μm ACh reduced microsomal eNOS content by -38 ± 9 %, -61 ± 16 % and -40 ± 18 %, respectively (n = 4-5). In all cases, microsomal Cav-1 content did not change. The close ACh concentration dependence and the concomitance between eNOS subcellular redistribution and NO release support the concept that eNOS translocation from the plasma membrane is part of an activation mechanism that induces NO-dependent vasodilatation in

The effects of endomorphins and diprotin A on striatal dopamine release induced by electrical stimulation-an in vitro superfusion study in rats.

PubMed

Bagosi, Zsolt; Jászberényi, Miklós; Bujdosó, Erika; Szabó, Gyula; Telegdy, Gyula

2006-12-01

The endomorphins (EM1: Tyr-Pro-Trp-Phe-NH2, and EM2: Tyr-Pro-Phe-Phe-NH2) are recently discovered endogenous ligands for mu-opioid receptors (MORs) with role of neurotransmitters or neuromodulators in mammals. Cessation of their physiological action may be effected through rapid enzymatic degradation by the dipeptidyl-peptidase IV (DPPIV) found in the brain synaptic membranes. An in vitro superfusion system was utilized to investigate the actions of EM1, EM2 and specific DPPIV inhibitor diprotin A on the striatal release of dopamine (DA) induced by electrical stimulation in rats. The involvement of the different MORs (MOR1 and MOR2) in this process was studied by pretreatment with MOR antagonists beta-funaltrexamine (a MOR1 and MOR2 antagonist) and naloxonazine (a MOR1 antagonist). EM1 significantly increased the tritium-labelled dopamine DA release induced by electrical stimulation. EM2 was effective only when the slices were pretreated with diprotin A. beta-Funaltrexamine antagonized the stimulatory effects of both EM1 and EM2. The administration of naloxonazine did not appreciably influence the action of EM1, but blocked the action of EM2, at least when the slices were pretreated with diprotin A. These data suggest that both EM1 and EM2 increase DA release from the striatum and, though diprotin A does not affect the action of EM1, it inhibits the enzymatic degradation of EM2. The DA-stimulating action induced by EM1 seems to be mediated by MOR2, while that evoked by EM2 appears to be transmitted by MOR1.

Activity of a new hydrogen sulfide-releasing aspirin (ACS14) on pathological cardiovascular alterations induced by glutathione depletion in rats.

PubMed

Rossoni, Giuseppe; Manfredi, Barbara; Tazzari, Valerio; Sparatore, Anna; Trivulzio, Silvio; Del Soldato, Piero; Berti, Ferruccio

2010-12-01

We investigated the effects of the hydrogen sulfide (H₂S)-releasing derivatives of aspirin (ACS14) and salicylic acid (ACS21) in a rat model of metabolic syndrome induced by glutathione (GSH) depletion, causing hypertension and other pathological cardiovascular alterations. GSH depletion was induced in normal rats by the GSH-synthase inhibitor buthionine sulfoximine (BSO, 30 mmol/L day for seven days in the drinking water). Systolic blood pressure and heart rate were measured daily by the tail-cuff method, and plasma thromboxane B₂, 6-keto-prostaglandin F(2α), 8-isoprostane, GSH, insulin and glucose were determined at the end of the seven-day BSO schedule. In addition, ischemia/reperfusion-induced myocardial dysfunction and endothelial dysfunction were assayed on isolated heart and aortic rings, respectively. Unlike aspirin and salicylic acid, ACS14 and ACS21 reduced BSO-induced hypertension, also lowering plasma levels of thromboxane B₂, 8-isoprostane and insulin, while GSH remained in the control range. Neither ACS14 nor ACS21 caused gastric lesions. Both restored the endothelial dysfunction observed in aortic rings from BSO-treated rats, and in ischemia/reperfusion experiments they lowered left ventricular end-diastolic pressure, consequently improving the developed pressure and the maximum rise and fall of left ventricular pressure. Together with this improvement of heart mechanics there were reductions in the activity of creatine kinase and lactate dehydrogenase in the cardiac perfusate. This implies that H₂S released by both ACS14 and ACS21 was involved in protecting the heart from ischemia/reperfusion, and significantly limited vascular endothelial dysfunction in aortic tissue and the related hypertension. Copyright © 2010 Elsevier B.V. All rights reserved.

Phospholipase A2 activation regulates cytotoxicity of methylmercury in vascular endothelial cells.

PubMed

Mazerik, Jessica N; Hagele, Thomas; Sherwani, Shariq; Ciapala, Valorie; Butler, Susan; Kuppusamy, M Lakshmi; Hunter, Melissa; Kuppusamy, Periannan; Marsh, Clay B; Parinandi, Narasimham L

2007-01-01

Mercury has been identified as a risk factor for cardiovascular disease among humans. Through diet, mainly fish consumption, humans are exposed to methylmercury, the biomethylated organic form of environmental mercury. As the endothelium is an important player in homeostasis of the cardiovascular system, here, the authors tested their hypothesis that methylmercury activates the lipid signaling enzyme phospholipase A(2) (PLA(2)) in vascular endothelial cells (ECs), causing upstream regulation of cytotoxicity. To test this hypothesis, the authors used bovine pulmonary artery ECs (BPAECs) cultured in monolayers, following labeling of their membrane phospholipids with [(3)H]arachidonic acid (AA). The cells were exposed to methylmercury chloride (MMC) and then the release of free AA (index of PLA(2) activity) and lactate dehydrogenase (LDH; index of cytotoxicity) were determined by liquid scintillation counting and spectrophotometry, respectively. MMC significantly activated PLA(2) in a dose-dependent (5 to 15 microM) and time-dependent (0 to 60 min) fashion. Sulfhydryl (thiol-protective) agents, calcium chelators, antioxidants, and PLA(2)-specific inhibitors attenuated the MMC-induced PLA(2) activation, suggesting the role of thiols, reactive oxygen species (ROS), and calcium in the activation of PLA(2) in BPAECs. MMC also induced the loss of thiols and increase of lipid peroxidation in BPAECs. MMC induced cytotoxicity in BPAECs as observed by the altered cell morphology and LDH leak, which was significantly attenuated by PLA(2) inhibitors. This study established that PLA(2) activation through thiols, calcium, and oxidative stress was associated with the cytotoxicity of MMC in BPAECs, drawing attention to the involvement of PLA(2) signaling in the methylmercury-induced vascular endothelial dysfunctions.

Piracetam ameliorated oxygen and glucose deprivation-induced injury in rat cortical neurons via inhibition of oxidative stress, excitatory amino acids release and P53/Bax.

PubMed

He, Zhi; Hu, Min; Zha, Yun-hong; Li, Zi-cheng; Zhao, Bo; Yu, Ling-ling; Yu, Min; Qian, Ying

2014-05-01

Our previous work has demonstrated that piracetam inhibited the decrease in amino acid content induced by chronic hypoperfusion, ameliorated the dysfunction of learning and memory in a hypoperfusion rat model, down-regulated P53, and BAX protein, facilitated the synaptic plasticity, and may be helpful in the treatment of vascular dementia. To explore the precise mechanism, the present study further evaluated effects of piracetam on Oxygen and glucose deprivation (OGD)-induced neuronal damage in rat primary cortical cells. The addition of piracetam to the cultured cells 12 h before OGD for 4 h significantly reduced neuronal damage as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and lactate dehydrogenase release experiments. Piracetam also lowered the levels of malondialdehyde, nitrogen monoxidum, and xanthine oxidase which was increased in the OGD cells, and enhanced the activities of superoxide dismutase and glutathione peroxidase, which were decreased in the OGD cells. We also demonstrated that piracetam could decrease glutamate and aspartate release when cortical cells were subjected to OGD. Furthermore, Western blot study demonstrated that piracetam attenuated the increased expression of P53 and BAX protein in OGD cells. These observations demonstrated that piracetam reduced OGD-induced neuronal damage by inhibiting the oxidative stress and decreasing excitatory amino acids release and lowering P53/Bax protein expression in OGD cells.

PF4/heparin-antibody complex induces monocyte tissue factor expression and release of tissue factor positive microparticles by activation of FcγRI

PubMed Central

Glover, Sam L.; Jonas, William; McEachron, Troy; Pawlinski, Rafal; Arepally, Gowthami M.; Key, Nigel S.; Mackman, Nigel

2012-01-01

Heparin-induced thrombocytopenia (HIT) is a potentially devastating form of drug-induced thrombocytopenia that occurs in patients receiving heparin for prevention or treatment of thrombosis. Patients with HIT develop autoantibodies to the platelet factor 4 (PF4)/heparin complex, which is termed the HIT Ab complex. Despite a decrease in the platelet count, the most feared complication of HIT is thrombosis. The mechanism of thrombosis in HIT remains poorly understood. We investigated the effects of the HIT Ab complex on tissue factor (TF) expression and release of TF-positive microparticles in peripheral blood mononuclear cells and monocytes. To model these effects ex vivo, we used a murine mAb specific for the PF4/heparin complex (KKO), as well as plasma from patients with HIT. We found that the HIT Ab complex induced TF expression in monocytes and the release of TF-positive microparticles. Further, we found that induction of TF is mediated via engagement of the FcγRI receptor and activation of the MEK1-ERK1/2 signaling pathway. Our data suggest that monocyte TF may contribute to the development of thrombosis in patients with HIT. PMID:22394597

Receptor activated bladder and spinal ATP release in neurally intact and chronic spinal cord injured rats

PubMed Central

Salas, Nilson A.; Somogyi, George T.; Gangitano, David A.; Boone, Timothy B.; Smith, Christopher P.

2009-01-01

Neurally intact (NI) rats and chronic spinal cord injured (SCI) rats were studied to determine how activation of mechanosensory or cholinergic receptors in the bladder urothelium evokes ATP release from afferent terminals in the bladder as well as in the spinal cord. Spinal cord transection was performed at the T9-T10 level 2–3 weeks prior to the experiment and a microdialysis fiber was inserted in the L6-S1 lumbosacral spinal cord. Mechanically evoked (i.e. 10cm/w bladder pressure) ATP release into the bladder lumen was approximately 6.5 fold higher in SCI compared to NI rats (p<0.05). Intravesical carbachol (CCh) induced a significantly greater release of ATP in the bladder from SCI as compared to NI rats (3424.32 ± 1255.57 vs. 613.74 ± 470.44 pmol/ml, respectively, p<0.05). However, ATP release in NI or SCI rats to intravesical CCh was not affected by the muscarinic antagonist atropine (Atr). Spinal release of ATP to bladder stimulation with 10cm/w pressure was 5-fold higher in SCI compared to NI rats (p<0.05). CCh also induced a significantly greater release of spinal ATP in SCI rats compared to controls (4.3 ± 0.9 vs. 0.90 ± 0.15 pmol, p < 0.05). Surprisingly, the percent inhibitory effect of Atr on CCh-induced ATP release was significantly less in SCI as compared to NI rats (49% vs. 89%, respectively). SCI induces a dramatic increase in intravesical pressure and cholinergic receptor evoked bladder and spinal ATP release. Muscarinic receptors do not mediate intravesical CCh induced ATP release into the bladder lumen in NI or SCI rats. In NI rats sensory muscarinic receptors are the predominant mechanism by which CCh induces ATP release from primary afferents within the lumbosacral spinal cord. Following SCI, however, nicotinic or purinergic receptor mechanisms become active, as evidenced by the fact that Atr was only partially effective in inhibiting CCh-induced spinal ATP release. PMID:17067723

Gender specific influence of endogenous glutamate release on stress-induced fear in rats.

PubMed

Jain, S K; Zelena, D

2011-01-01

Stress, fear and anxiety are among major public health concerns. The role of glutamate in these processes is becoming more recognized with promising new drug targets. The aim of this study was to establish the gender specificity of a possible treatment of fear by glutamate antagonists in correspondence with changes in stress-hormone release. Footshock-induced fear was used as an anxiogenic situation in rats. A combination of two ionotrop receptor antagonists such as MK-801 (dizocilpine; 0.2 mg/kg) for NMDA (N-methyl-D-aspartic acid) and GYKI 52466 (benzodiazepine derivative; 10 mg/kg) for AMPA/kainate receptors were used for 5 days following the hypothesis that they potentiate each other the main action, but at the same time the side effects may be minimized. Female rats tried to avoid the electrical stimulus more actively than males, as they spent more time with exploration and jumping and less time with freezing or rest. Ionotropic glutamate receptor antagonists have anxiolytic action. MK-801 was more effective in females, as it prevented the footshock-induced freezing per se, while in males it was effective only in combination with GyKI 52466. The locomotor side effect of MK-801 was not visible after repeated administration. The freezing behavior was positively correlated with the changes in prolactin but not with adrenocorticotropin levels. We proved the involvement of endogenous glutamate neurotransmission in stress-induced fear. Therapeutical usage may involve a combination of different receptor antagonists. Special attention should be paid to the gender, as females seem to be more sensitive, therefore they require smaller doses. During the treatment the prolactin levels should be monitored.

Macrophage migration inhibitory factor counter-regulates dexamethasone-induced annexin 1 expression and influences the release of eicosanoids in murine macrophages.

PubMed

Sun, Yu; Wang, Yu; Li, Jia-Hui; Zhu, Shi-Hui; Tang, Hong-Tai; Xia, Zhao-Fan

2013-10-01

Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine and glucocorticoid (GC) counter-regulator, has emerged as an important modulator of inflammatory responses. However, the molecular mechanisms of MIF counter-regulation of GC still remain incomplete. In the present study, we investigated whether MIF mediated the counter-regulation of the anti-inflammatory effect of GC by affecting annexin 1 in RAW 264.7 macrophages. We found that stimulation of RAW 264.7 macrophages with lipopolysaccharide (LPS) resulted in down-regulation of annexin 1, while GC dexamethasone (Dex) or Dex plus LPS led to significant up-regulation of annexin 1 expression. RNA interference-mediated knockdown of intracellular MIF increased annexin 1 expression with or without incubation of Dex, whereas Dex-induced annexin 1 expression was counter-regulated by the exogenous application of recombinant MIF. Moreover, recombinant MIF counter-regulated, in a dose-dependent manner, inhibition of cytosolic phospholipase A2α (cPLA2α) activation and prostaglandin E2 (PGE2 ) and leukotriene B4 (LTB4 ) release by Dex in RAW 264.7 macrophages stimulated with LPS. Endogenous depletion of MIF enhanced the effects of Dex, reflected by further decease of cPLA2α expression and lower PGE2 and LTB4 release in RAW 264.7 macrophages. Based on these data, we suggest that MIF counter-regulates Dex-induced annexin 1 expression, further influencing the activation of cPLA2α and the release of eicosanoids. These findings will add new insights into the mechanisms of MIF counter-regulation of GC. © 2013 John Wiley & Sons Ltd.

Leishmania amazonensis fails to induce the release of reactive oxygen intermediates by CBA macrophages.

PubMed

Almeida, T F; Palma, L C; Mendez, L C; Noronha-Dutra, A A; Veras, P S T

2012-10-01

CBA mouse macrophages effectively control Leishmania major infection, yet are permissive to Leishmania amazonensis. It has been established that some Leishmania species are destroyed by reactive oxygen species (ROS). However, other species of Leishmania exhibit resistance to ROS or even down-modulate ROS production. We hypothesized that L. amazonensis-infected macrophages reduce ROS production soon after parasite-cell interaction. Employing a highly sensitive analysis technique based on chemiluminescence, the production of superoxide (O(·-)(2)) and hydrogen peroxide (H(2)O(2)) by L. major- or L. amazonensis-infected CBA macrophages were measured. L. major induces macrophages to release levels of (O(·-)(2)) 3·5 times higher than in uninfected cells. This (O(·-)(2)) production is partially dependent on NADPH oxidase (NOX) type 2. The level of accumulated H(2)O(2) is 20 times higher in L. major-than in L. amazonensis-infected cells. Furthermore, macrophages stimulated with L. amazonensis release amounts of ROS similar to uninfected cells. These findings support previous studies showing that CBA macrophages are effective in controlling L. major infection by a mechanism dependent on both (O(·-)(2)) production and H(2)O(2) generation. Furthermore, these data reinforce the notion that L. amazonensis survive inside CBA macrophages by reducing ROS production during the phagocytic process. © 2012 Blackwell Publishing Ltd.

Role of Hypothalamic-Pituitary-Adrenal axis and corticotropin-releasing factor stress system on cue-induced relapse to alcohol seeking.

PubMed

Galesi, Fernanda L; Ayanwuyi, Lydia O; Mijares, Miriam Garcia; Cippitelli, Andrea; Cannella, Nazzareno; Ciccocioppo, Roberto; Ubaldi, Massimo

2016-10-05

A large body of evidence has shown that the Corticotropin Releasing Factor (CRF) system, which plays a key role in stress modulation, is deeply involved in relapse to alcohol seeking induced by exposure to stressful events such as foot shock or yohimbine injections. Exposure to environmental cues is also known to be a trigger for alcohol relapse, nevertheless, the relationship between the relapse evoked by the cue-induced model and the CRF stress systems remains unclear. The purpose of this study was to evaluate, in male Wistar rats, the involvement of the CRF system and Hypothalamic-Pituitary-Adrenal (HPA) axis in relapse induced by environmental cues. Antalarmin, a selective CRF1 receptor antagonist, Metyrapone, a corticosterone (CORT) synthesis inhibitor and CORT were evaluated for their effects on the reinstatement test in a cue-induced relapse model. Antalarmin (20mg/kg) blocked relapse to alcohol seeking induced by environmental cues. Metyrapone (50 and 100mg/kg) also blocked relapse in Wistar rats but only at the highest dose (100mg/kg). Corticosterone had no effect on relapse at the doses tested. The results obtained from this study suggest that the CRF stress system and the HPA axis are involved in cue-induced alcohol relapse. Copyright © 2016 Elsevier B.V. All rights reserved.

Cannabidiol, a Cannabis sativa constituent, inhibits cocaine-induced seizures in mice: Possible role of the mTOR pathway and reduction in glutamate release.

PubMed

Gobira, Pedro H; Vilela, Luciano R; Gonçalves, Bruno D C; Santos, Rebeca P M; de Oliveira, Antonio C; Vieira, Luciene B; Aguiar, Daniele C; Crippa, José A; Moreira, Fabricio A

2015-09-01

Cannabidiol (CBD), a major non-psychotomimetic constituent of Cannabis sativa, has therapeutic potential for certain psychiatric and neurological disorders. Studies in laboratory animals and limited human trials indicate that CBD has anticonvulsant and neuroprotective properties. Its effects against cocaine neurotoxicity, however, have remained unclear. Thus, the present study tested the hypothesis that CBD protects against cocaine-induced seizures and investigated the underlying mechanisms. CBD (30 mg/kg) pre-treatment increased the latency and reduced the duration of cocaine (75 mg/kg)-induced seizures in mice. The CB1 receptor antagonist, AM251 (1 and 3mg/kg), and the CB2 receptor antagonist, AM630 (2 and 4 mg/kg), failed to reverse this protective effect, suggesting that alternative mechanisms are involved. Synaptosome studies with the hippocampus of drug-treated animals revealed that cocaine increases glutamate release, whereas CBD induces the opposite effect. Finally, the protective effect of this cannabinoid against cocaine-induced seizure was reversed by rapamycin (1 and 5mg/kg), an inhibitor of the mammalian target of rapamycin (mTOR) intracellular pathway. In conclusion, CBD protects against seizures in a model of cocaine intoxication. These effects possibly occur through activation of mTOR with subsequent reduction in glutamate release. CBD should be further investigated as a strategy for alleviating psychostimulant toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Preabsorptive insulin release and hypoglycemia in rats.

PubMed

Louis-Sylvestre, J

1976-01-01

Peripheral blood glucose and immunologically reactive insulin levels were determined in freely moving normal rats which were submitted either to a free oral glucose load or to a gastric administration of the glucose load. Identical determinations were performed in ventromedial hypothalamic nucleus-(VMH) lesioned and vagotomized rats after the same oral intake. It was demonstrated that: 1) a free oral glucose intake was immediately followed by two peaks of insulun release and a resultant decrease in blood glucose; 2) a gastric glucose load resulted in a single peak of insulin release and the concomitant decline in blood glucose; 3) the recorded blood glucose level was the resultant of the insulin-induced hypoglycemia and the postabsorptive hyperglycemia; and 4) the responses were largely exaggerated in VMH-lesioned rats and abolished by vagotomy. It is concluded that the early prandial insulin release reflexly induced by food-related stimuli temporarily enhances the metabolic conditions which provoke feeding.

AGE/RAGE-Induced EMP Release via the NOX-Derived ROS Pathway

PubMed Central

Chen, Ying-Hua; Chen, Zhang-Wei; Li, Hong-Mei

2018-01-01

Objective Diabetes is associated with accelerated formation of advanced glycation end products (AGEs) that are extensively found in circulating endothelial microparticles (EMPs). This study aimed to investigate whether AGEs have a direct effect on EMP formation and the possible underlying mechanism. Methods In vitro, cultured human umbilical vein endothelial cells (HUVECs) were incubated with AGEs (200 and 400 μg/ml) for 24 hours with or without pretreatment with anti-RAGE antibody, NOX inhibitor, or ROS scavenger. The number of CD31-positive EMPs was assessed by flow cytometry. Results The number of EMPs was significantly increased in HUVECs stimulated by AGEs in a dose-dependent manner. In addition, receptors for AGEs (RAGE), NAD(P)H oxidase (NOX), and reactive oxygen species (ROS) were increased by AGEs as compared to the control group. These changes could be reversed when HUVECs were pretreated with anti-RAGE antibody. Moreover, inhibition of NOX as well as antioxidant treatment reduced the release of EMPs induced by AGEs. Conclusion Our study suggested that AGEs increased EMP generation, which was mediated by RAGE signaling through NOX-derived ROS. PMID:29744367

Schizophrenia-Like Dopamine Release Abnormalities in a Mouse Model of NMDA Receptor Hypofunction.

PubMed

Nakao, Kazuhito; Jeevakumar, Vivek; Jiang, Sunny Zhihong; Fujita, Yuko; Diaz, Noelia B; Pretell Annan, Carlos A; Eskow Jaunarajs, Karen L; Hashimoto, Kenji; Belforte, Juan E; Nakazawa, Kazu

2018-01-31

Amphetamine-induced augmentation of striatal dopamine and its blunted release in prefrontal cortex (PFC) is a hallmark of schizophrenia pathophysiology. Although N-methyl-D-aspartate receptor (NMDAR) hypofunction is also implicated in schizophrenia, it remains unclear whether NMDAR hypofunction leads to dopamine release abnormalities. We previously demonstrated schizophrenia-like phenotypes in GABAergic neuron-specific NMDAR hypofunctional mutant mice, in which Ppp1r2-Cre dependent deletion of indispensable NMDAR channel subunit Grin1 is induced in corticolimbic GABAergic neurons including parvalbumin (PV)-positive neurons, in postnatal development, but not in adulthood. Here, we report enhanced dopaminomimetic-induced locomotor activity in these mutants, along with bidirectional, site-specific changes in in vivo amphetamine-induced dopamine release: nucleus accumbens (NAc) dopamine release was enhanced by amphetamine in postnatal Ppp1r2-Cre/Grin1 knockout (KO) mice, whereas dopamine release was dramatically reduced in the medial PFC (mPFC) compared to controls. Basal tissue dopamine levels in both the NAc and mPFC were unaffected. Interestingly, the magnitude and distribution of amphetamine-induced c-Fos expression in dopamine neurons was comparable between genotypes across dopaminergic input subregions in the ventral tegmental area (VTA). These effects appear to be both developmentally and cell-type specifically modulated, since PV-specific Grin1 KO mice could induce the same effects as seen in postnatal-onset Ppp1r2-Cre/Grin1 KO mice, but no such abnormalities were observed in somatostatin-Cre/Grin1 KO mice or adult-onset Ppp1r2-Cre/Grin1 KO mice. These results suggest that PV GABAergic neuron-NMDAR hypofunction in postnatal development confers bidirectional NAc hyper- and mPFC hypo-sensitivity to amphetamine-induced dopamine release, similar to that classically observed in schizophrenia pathophysiology. © The Author(s) 2018. Published by Oxford University

Involvement of TRPV1 in the expression and release of calcitonin gene-related peptide induced by rutaecarpine.

PubMed

Yang, Yongmei; Chen, Qingquan; Jia, Sujie; He, Limei; Wang, Aiping; Li, Dai; Li, Yuanjian; Li, Xiaohui

2018-04-01

The traditional Chinese herb Wu-Chu-Yu has been used to treat hypertension for hundreds of years. A previous study indicated that rutaecarpine was the effective component of Wu‑Chu‑Yu, which lowered blood pressure by elevating the expression level of calcitonin gene‑related peptide (CGRP). The present study was performed to investigate the role of transient receptor potential cation channel subfamily V member 1 (TRPV1) in CGRP expression and release induced by rutaecarpine. Dorsal root ganglia (DRG) obtained from Sprague‑Dawley rats were cultured to analyze the mRNA expression and release of CGRP. Calcium influx, as an indicator of TRPV1 activation, was measured in 293 cells with stable overexpression of TRPV1. The results demonstrated that the amount of CGRP in the cell culture supernatant and the mRNA expression of CGRPα and CGRPβ in DRG was upregulated by rutaecarpine in a concentration‑dependent manner, and was inhibited by the TRPV1 receptor antagonist capsazepine. In addition, intracellular Ca2+ levels were increased by Rut in the aforementioned 293 cell line, indicating the activation of TRPV1 by Rut. Therefore, it was concluded that TRPV1 was involved in the expression and release of CGRP stimulated by rutaecarpine, which provided novel mechanistic understanding of the treatment of hypertension using the Chinese herb Wu-Chu-Yu.

Fluid shear stress induces upregulation of COX-2 and PGI2 release in endothelial cells via a pathway involving PECAM-1, PI3K, FAK, and p38.

PubMed

Russell-Puleri, Sparkle; Dela Paz, Nathaniel G; Adams, Diana; Chattopadhyay, Mitali; Cancel, Limary; Ebong, Eno; Orr, A Wayne; Frangos, John A; Tarbell, John M

2017-03-01

Vascular endothelial cells play an important role in the regulation of vascular function in response to mechanical stimuli in both healthy and diseased states. Prostaglandin I 2 (PGI 2 ) is an important antiatherogenic prostanoid and vasodilator produced in endothelial cells through the action of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2. However, the mechanisms involved in sustained, shear-induced production of COX-2 and PGI 2 have not been elucidated but are determined in the present study. We used cultured endothelial cells exposed to steady fluid shear stress (FSS) of 10 dyn/cm 2 for 5 h to examine shear stress-induced induction of COX-2/PGI 2 Our results demonstrate the relationship between the mechanosensor platelet endothelial cell adhesion molecule-1 (PECAM-1) and the intracellular mechanoresponsive molecules phosphatidylinositol 3-kinase (PI3K), focal adhesion kinase (FAK), and mitogen-activated protein kinase p38 in the FSS induction of COX-2 expression and PGI 2 release. Knockdown of PECAM-1 (small interference RNA) expression inhibited FSS-induced activation of α 5 β 1 -integrin, upregulation of COX-2, and release of PGI 2 in both bovine aortic endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs). Furthermore, inhibition of the PI3K pathway (LY294002) substantially inhibited FSS activation of α 5 β 1 -integrin, upregulation of COX-2 gene and protein expression, and release of PGI 2 in BAECs. Inhibition of integrin-associated FAK (PF573228) and MAPK p38 (SB203580) also inhibited the shear-induced upregulation of COX-2. Finally, a PECAM-1 -/- mouse model was characterized by reduced COX-2 immunostaining in the aorta and reduced plasma PGI 2 levels compared with wild-type mice, as well as complete inhibition of acute flow-induced PGI 2 release compared with wild-type animals. NEW & NOTEWORTHY In this study we determined the major mechanotransduction pathway by which blood flow-driven shear stress activates

Fluid shear stress induces upregulation of COX-2 and PGI2 release in endothelial cells via a pathway involving PECAM-1, PI3K, FAK, and p38

PubMed Central

Russell-Puleri, Sparkle; dela Paz, Nathaniel G.; Adams, Diana; Chattopadhyay, Mitali; Cancel, Limary; Ebong, Eno; Orr, A. Wayne; Frangos, John A.

2017-01-01

Vascular endothelial cells play an important role in the regulation of vascular function in response to mechanical stimuli in both healthy and diseased states. Prostaglandin I2 (PGI2) is an important antiatherogenic prostanoid and vasodilator produced in endothelial cells through the action of the cyclooxygenase (COX) isoenzymes COX-1 and COX-2. However, the mechanisms involved in sustained, shear-induced production of COX-2 and PGI2 have not been elucidated but are determined in the present study. We used cultured endothelial cells exposed to steady fluid shear stress (FSS) of 10 dyn/cm2 for 5 h to examine shear stress-induced induction of COX-2/PGI2. Our results demonstrate the relationship between the mechanosensor platelet endothelial cell adhesion molecule-1 (PECAM-1) and the intracellular mechanoresponsive molecules phosphatidylinositol 3-kinase (PI3K), focal adhesion kinase (FAK), and mitogen-activated protein kinase p38 in the FSS induction of COX-2 expression and PGI2 release. Knockdown of PECAM-1 (small interference RNA) expression inhibited FSS-induced activation of α5β1-integrin, upregulation of COX-2, and release of PGI2 in both bovine aortic endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs). Furthermore, inhibition of the PI3K pathway (LY294002) substantially inhibited FSS activation of α5β1-integrin, upregulation of COX-2 gene and protein expression, and release of PGI2 in BAECs. Inhibition of integrin-associated FAK (PF573228) and MAPK p38 (SB203580) also inhibited the shear-induced upregulation of COX-2. Finally, a PECAM-1−/− mouse model was characterized by reduced COX-2 immunostaining in the aorta and reduced plasma PGI2 levels compared with wild-type mice, as well as complete inhibition of acute flow-induced PGI2 release compared with wild-type animals. NEW & NOTEWORTHY In this study we determined the major mechanotransduction pathway by which blood flow-driven shear stress activates cyclooxygenase-2 (COX-2

Morphine sulfate and naltrexone hydrochloride extended-release capsules: naltrexone release, pharmacodynamics, and tolerability.

PubMed

Johnson, Franklin; Setnik, Beatrice

2011-01-01

Morphine sulfate and naltrexone hydrochloride extended-release capsules (EMBEDA, King Pharmaceuticals, Inc., Bristol, TN), indicated for management of chronic, moderate-to-severe pain, contain pellets of extended-release morphine sulfate with a sequestered naltrexone core (MS-sNT). Taken as directed, morphine provides analgesia while naltrexone remains sequestered; if tampered with by crushing, naltrexone is released to mitigate morphine-induced euphoric effects. While it is necessary to establish that formulations intended to reduce attractiveness for abuse are successful in doing so, it is also necessary to demonstrate that product therapeutic integrity is maintained for patients. Data were reviewed from 3 studies to determine: 1) the quantity of naltrexone released when MS-sNT pellets are crushed (MS-sNTC) for at least 2 minutes with mortar and pestle); 2) the extent to which the naltrexone released upon crushing mitigated morphine-induced subjective effects; and 3) whether sequestered naltrexone precipitates opioid withdrawal when MS-sNT is taken as directed. The naltrexone bioavailability study compared naltrexone release from MS-sNTC with that from whole intact MS-sNT capsules (MS-sNTW) and an equal naltrexone solution (NS) dose. Equivalent bioavailability was established if 90% confidence intervals (CIs) for geometric mean ratios (maximum plasma naltrexone concentration [Cmax] and area under the concentration-time curve extrapolated to infinity [AUC∞]) fell between 80% and 125%. The oral pharmacodynamic study assessed drug liking and euphoria and pharmacokinetic properties of MS-sNTC and MS-sNTW compared with morphine sulfate solution (MSS) and placebo. The 12-month, open-label (OL) safety study evaluated safety of MS-sNT administered orally as directed in patients with chronic, moderate-to-severe pain. Safety assessments included withdrawal symptoms based on the Clinical Opiate Withdrawal Scale (COWS). Naltrexone from MS-sNTC met criteria for equivalent

The effects of endomorphins on striatal [3H]GABA release induced by electrical stimulation: an in vitro superfusion study in rats.

PubMed

Bagosi, Zsolt; Jászberényi, Miklós; Telegdy, Gyula

2009-05-01

The endomorphins (EM1 and EM2) are selective endogenous ligands for mu-opioid receptors (MOR1 and MOR2) with neurotransmitter and neuromodulator roles in mammals. In the present study we investigated the potential actions of EMs on striatal GABA release and the implication of different MORs in these processes. Rat striatal slices were preincubated with tritium-labelled GABA ([(3)H]GABA), pretreated with selective MOR1 and MOR2 antagonist beta-funaltrexamine and selective MOR1 antagonist naloxonazine and then superfused with the selective MOR agonists, EM1 and EM2. EM1 significantly decreased the striatal [(3)H]GABA release induced by electrical stimulation. Beta-funaltrexamine antagonized the inhibitory action of EM1, but naloxonazine did not affect it considerably. EM2 was ineffective, even in case of specific enzyme inhibitor diprotin A pretreatment. The results demonstrate that EM1 decreases GABA release in the basal ganglia through MOR2, while EM2 does not influence it.

Lithium carbonate as a treatment for paliperidone extended-release-induced leukopenia and neutropenia in a patient with schizoaffective disorder; a case report.

PubMed

Matsuura, Hiroki; Kimoto, Sohei; Harada, Izumi; Naemura, Satoshi; Yamamuro, Kazuhiko; Kishimoto, Toshifumi

2016-05-26

Antipsychotic drug treatment can potentially lead to adverse events such as leukopenia and neutropenia. Although these events are rare, they represent serious and life-threatening hematological side effects. We present a case study of a patient with schizoaffective disorder in a 50-year-old woman. We report a case of paliperidone extended-release (ER)-induced leukopenia and neutropenia in a female patient with schizoaffective disorder. Initiating lithium carbonate treatment and decreasing the dose of valproic acid improved the observed leukopenia and neutropenia. This treatment did not influence psychotic symptoms. The combination of paliperidone ER and valproic acid induces increased paliperidone ER plasma levels. Lithium carbonate was successfully used to treat paliperidone ER-induced leukopenia and neutropenia.

Pulsed magnetic field induced fast drug release from magneto liposomes via ultrasound generation.

PubMed

Podaru, George; Ogden, Saralyn; Baxter, Amanda; Shrestha, Tej; Ren, Shenqiang; Thapa, Prem; Dani, Raj Kumar; Wang, Hongwang; Basel, Matthew T; Prakash, Punit; Bossmann, Stefan H; Chikan, Viktor

2014-10-09

Fast drug delivery is very important to utilize drug molecules that are short-lived under physiological conditions. Techniques that can release model molecules under physiological conditions could play an important role to discover the pharmacokinetics of short-lived substances in the body. Here an experimental method is developed for the fast release of the liposomes' payload without a significant increase in (local) temperatures. This goal is achieved by using short magnetic pulses to disrupt the lipid bilayer of liposomes loaded with magnetic nanoparticles. The drug release has been tested by two independent assays. The first assay relies on the AC impedance measurements of MgSO4 released from the magnetic liposomes. The second standard release assay is based on the increase of the fluorescence signal from 5(6)-carboxyfluorescein dye when the dye is released from the magneto liposomes. The efficiency of drug release ranges from a few percent to up to 40% in the case of the MgSO4. The experiments also indicate that the magnetic nanoparticles generate ultrasound, which is assumed to have a role in the release of the model drugs from the magneto liposomes.

CB1 Cannabinoid Receptors Couple to Focal Adhesion Kinase to Control Insulin Release*

PubMed Central

Malenczyk, Katarzyna; Jazurek, Magdalena; Keimpema, Erik; Silvestri, Cristoforo; Janikiewicz, Justyna; Mackie, Ken; Di Marzo, Vincenzo; Redowicz, Maria J.; Harkany, Tibor; Dobrzyn, Agnieszka

2013-01-01

Endocannabinoid signaling has been implicated in modulating insulin release from β cells of the endocrine pancreas. β Cells express CB1 cannabinoid receptors (CB1Rs), and the enzymatic machinery regulating anandamide and 2-arachidonoylglycerol bioavailability. However, the molecular cascade coupling agonist-induced cannabinoid receptor activation to insulin release remains unknown. By combining molecular pharmacology and genetic tools in INS-1E cells and in vivo, we show that CB1R activation by endocannabinoids (anandamide and 2-arachidonoylglycerol) or synthetic agonists acutely or after prolonged exposure induces insulin hypersecretion. In doing so, CB1Rs recruit Akt/PKB and extracellular signal-regulated kinases 1/2 to phosphorylate focal adhesion kinase (FAK). FAK activation induces the formation of focal adhesion plaques, multimolecular platforms for second-phase insulin release. Inhibition of endocannabinoid synthesis or FAK activity precluded insulin release. We conclude that FAK downstream from CB1Rs mediates endocannabinoid-induced insulin release by allowing cytoskeletal reorganization that is required for the exocytosis of secretory vesicles. These findings suggest a mechanistic link between increased circulating and tissue endocannabinoid levels and hyperinsulinemia in type 2 diabetes. PMID:24089517

Caspase-3 mediated release of SAC domain containing fragment from Par-4 is necessary for the sphingosine-induced apoptosis in Jurkat cells

PubMed Central

2013-01-01

Background Prostate apoptosis response-4 (Par-4) is a tumor-suppressor protein that selectively activates and induces apoptosis in cancer cells, but not in normal cells. The cancer specific pro-apoptotic function of Par-4 is encoded in its centrally located SAC (Selective for Apoptosis induction in Cancer cells) domain (amino acids 137–195). The SAC domain itself is capable of nuclear entry, caspase activation, inhibition of NF-κB activity, and induction of apoptosis in cancer cells. However, the precise mechanism(s) of how the SAC domain is released from Par-4, in response to apoptotic stimulation, is not well explored. Results In this study, we demonstrate for the first time that sphingosine (SPH), a member of the sphingolipid family, induces caspase-dependant cleavage of Par-4, leading to the release of SAC domain containing fragment from it. Par-4 is cleaved at the EEPD131G site on incubation with caspase-3 in vitro, and by treating cells with several anti-cancer agents. The caspase-3 mediated cleavage of Par-4 is blocked by addition of the pan-caspase inhibitor z-VAD-fmk, caspase-3 specific inhibitor Ac-DEVD-CHO, and by introduction of alanine substitution for D131 residue. Moreover, suppression of SPH-induced Akt dephosphorylation also abrogated the caspase dependant cleavage of Par-4. Conclusion Evidence provided here shows that Par-4 is cleaved by caspase-3 during SPH-induced apoptosis. Cleavage of Par-4 leads to the generation of SAC domain containing fragment which may possibly be essential and sufficient to induce or augment apoptosis in cancer cells. PMID:23442976

Impairment of Release Site Clearance within the Active Zone by Reduced SCAMP5 Expression Causes Short-Term Depression of Synaptic Release.

PubMed

Park, Daehun; Lee, Unghwi; Cho, Eunji; Zhao, Haiyan; Kim, Jung Ah; Lee, Byoung Ju; Regan, Philip; Ho, Won-Kyung; Cho, Kwangwook; Chang, Sunghoe

2018-03-20

Despite being a highly enriched synaptic vesicle (SV) protein and a candidate gene for autism, the physiological function of SCAMP5 remains mostly enigmatic. Here, using optical imaging and electrophysiological experiments, we demonstrate that SCAMP5 plays a critical role in release site clearance at the active zone. Truncation analysis revealed that the 2/3 loop domain of SCAMP5 directly interacts with adaptor protein 2, and this interaction is critical for its role in release site clearance. Knockdown (KD) of SCAMP5 exhibited pronounced synaptic depression accompanied by a slower recovery of the SV pool. Moreover, it induced a strong frequency-dependent short-term depression of synaptic release, even under the condition of sufficient release-ready SVs. Super-resolution microscopy further proved the defects in SV protein clearance induced by KD. Thus, reduced expression of SCAMP5 may impair the efficiency of SV clearance at the active zone, and this might relate to the synaptic dysfunction observed in autism. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Differential Signalling and Kinetics of Neutrophil Extracellular Trap Release Revealed by Quantitative Live Imaging.

PubMed

van der Linden, Maarten; Westerlaken, Geertje H A; van der Vlist, Michiel; van Montfrans, Joris; Meyaard, Linde

2017-07-26

A wide variety of microbial and inflammatory factors induce DNA release from neutrophils as neutrophil extracellular traps (NETs). Consensus on the kinetics and mechanism of NET release has been hindered by the lack of distinctive methods to specifically quantify NET release in time. Here, we validate and refine a semi-automatic live imaging approach for quantification of NET release. Importantly, our approach is able to correct for neutrophil input and distinguishes NET release from neutrophil death by other means, aspects that are lacking in many NET quantification methods. Real time visualization shows that opsonized S. aureus rapidly induces cell death by toxins, while actual NET formation occurs after 90 minutes, similar to the kinetics of NET release by immune complexes and PMA. Inhibition of SYK, PI3K and mTORC2 attenuates NET release upon challenge with physiological stimuli but not with PMA. In contrast, neutrophils from chronic granulomatous disease patients show decreased NET release only in response to PMA. With this refined method, we conclude that NET release in primary human neutrophils is dependent on the SYK-PI3K-mTORC2 pathway and that PMA stimulation should be regarded as mechanistically distinct from NET formation induced by natural triggers.

Intracellular sphingosine releases calcium from lysosomes.

PubMed

Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

2015-11-27

To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC.

Corticotropin-releasing hormone regulates IL-6 expression during inflammation

PubMed Central

Venihaki, Maria; Dikkes, Pieter; Carrigan, Allison; Karalis, Katia P.

2001-01-01

Stimulation of the hypothalamic-pituitary-adrenal (HPA) axis by proinflammatory cytokines results in increased release of glucocorticoid that restrains further development of the inflammatory process. IL-6 has been suggested to stimulate the HPA axis during immune activation independent of the input of hypothalamic corticotropin-releasing hormone (CRH). We used the corticotropin-releasing hormone–deficient (Crh+/+) mouse to elucidate the effect of CRH deficiency on IL-6 expression and IL-6–induced HPA axis activation during turpentine-induced inflammation. We demonstrate that during inflammation CRH is required for a normal adrenocorticotropin hormone (ACTH) increase but not for adrenal corticosterone rise. The paradoxical increase of plasma IL-6 associated with CRH deficiency suggests that IL-6 release during inflammation is CRH-dependent. We also demonstrate that adrenal IL-6 expression is CRH-dependent, as its basal and inflammation-induced expression is blocked by CRH deficiency. Our findings suggest that during inflammation, IL-6 most likely compensates for the effects of CRH deficiency on food intake. Finally, we confirm that the HPA axis response is defective in Crh+/+/IL-6+/+ mice. These findings, along with the regulation of IL-6 by CRH, support the importance of the interaction between the immune system and the HPA axis in the pathophysiology of inflammatory diseases. PMID:11602623

Nitric oxide released by Lactobacillus farciminis improves TNBS-induced colitis in rats.

PubMed

Lamine, F; Fioramonti, J; Bueno, L; Nepveu, F; Cauquil, E; Lobysheva, I; Eutamène, H; Théodorou, V

2004-01-01

Beneficial effects of lactobacilli have been reported in experimental colitis. On the other hand, despite the controversial role of nitric oxide (NO) in the inflammatory gut process, a protective action of exogenous NO in inflammation has been suggested. Consequently, this study aimed to determine the effect of (i) sodium nitroprusside (SNP), a NO donor and (ii) treatment with Lactobacillus farciminis, which produces NO in vitro, on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats and to evaluate the role of exogenous NO in this effect. Rats were divided into three groups receiving one of the following: (i) a continuous intracolonic (IC) infusion of SNP for 4 days, (ii) L. farciminis orally for 19 days, or (iii) saline. On day 1 and day 15, respectively, TNBS and saline were administrated IC, followed by a continuous IC infusion of saline or haemoglobin, a NO scavenger. At the end of treatments, the following parameters were evaluated: macroscopic damage of colonic mucosa, myeloperoxidase and nitric oxide synthase activities and colonic luminal NO production. In colitic rats, SNP and L. farciminis treatment significantly (P < 0.05) reduced macroscopic damage scores, myeloperoxidase and nitric oxide synthase activities compared to controls. Haemoglobin infusion abolished the anti-inflammatory effect of both NO donor treatments, but had no effect per se on colitis. NO released intraluminally by SNP infusion or by L. farciminis given orally improves TNBS-induced colitis in rats. These results indicate a protective role of NO donation in colonic inflammation and show for the first time a mechanism involving NO delivery by a bacterial strain reducing an experimental colitis.

Zoledronate and Ion-releasing Resins Impair Dentin Collagen Degradation

PubMed Central

Tezvergil-Mutluay, A.; Seseogullari-Dirihan, R.; Feitosa, V.P.; Tay, F.R.; Watson, T.F.; Pashley, D.H.; Sauro, S.

2014-01-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. PMID:25074494

Photocontrol of Drug Release from Supramolecular Hydrogels with Green Light.

PubMed

Karcher, Johannes; Pianowski, Zbigniew

2018-06-26

Photoresponsive smart materials transform light energy into sophisticated functions. They find increasing biomedical applications in light-induced drug release and photopharmacology, as they can locally provide the desired therapeutic effect due to precise spatiotemporal dosage control. However, the majority of reported studies rely on cytotoxic UV light that poorly penetrates tissues. Here we report the first drug-releasing system based on photochromic low molecular weight supramolecular hydrogels that is triggered with visible light. We demonstrated green-light-induced release of structurally unmodified antibiotic, anticancer, and anti-inflammatory drugs under physiological conditions. Using the antibiotic-loaded gel, we selectively inhibited bacterial growth with green light. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Induction of HO-1 by carbon monoxide releasing molecule-2 attenuates thrombin-induced COX-2 expression and hypertrophy in primary human cardiomyocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chien, Peter Tzu-Yu; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan, Taiwan; Lin, Chih-Chung

Carbon monoxide (CO) is one of the cytoprotective byproducts of heme oxygenase (HO)-1 and exerts anti-inflammatory action in various models. However, the detailed mechanisms underlying CO-induced HO-1 expression in primary human cardiomyocytes remain largely unidentified. We used primary left ventricle myocytes as a model and applied CO releasing molecule (CORM)-2 to investigate the relationship of CO and HO-1 expression. We herein used Western blot, real-time PCR, promoter activity and EIA to investigate the role of HO-1 expression protecting against thrombin-mediated responses. We found that thrombin-induced COX-2 expression, PGE{sub 2} release and cardiomyocyte hypertrophy markers (increase in ANF/BNP, α-actin expression andmore » cell surface area) was attenuated by pretreatment with CORM-2 which was partially reversed by hemoglobin (Hb) or ZnPP (an inhibitor of HO-1 activity), suggesting that HO-1/CO system may be of clinical importance to ameliorate heart failure through inhibition of inflammatory responses. CORM-2-induced HO-1 protein expression, mRNA and promoter was attenuated by pretreatment with the inhibitors of Pyk2 (PF431396), PDGFR (AG1296), PI3K (LY294002), Akt (SH-5), p38 (SB202530), JNK1/2 (SP600125), FoxO1 (AS1842856) and Sp1 (mithramycin A). The involvement of these signaling components was further confirmed by transfection with respective siRNAs, consistent with those of pharmacological inhibitors. These results suggested that CORM-2-induced HO-1 expression is mediated through a Pyk2/PDGFR/PI3K/Akt/FoxO1/Sp1-dependent manner and exerts a cytoprotective effect in human cardiomyocytes. - Graphical abstract: In summary, CORM-2 treatment induces Pyk2 transactivated PDGFR, which induces PI3K/Akt/MAPK activation, and then recruits Sp1/Foxo1 transcriptional factors to regulate HO-1 gene expression in primary human cardiomyocytes. - Highlights: • CORM-2 induces HO-1 expression. • Pyk2-dependent PDGFR activates PI3K/Akt/MAPK pathway in CORM-2

Steroid Receptor Coactivator-interacting Protein (SIP) Inhibits Caspase-independent Apoptosis by Preventing Apoptosis-inducing Factor (AIF) from Being Released from Mitochondria*

PubMed Central

Wang, Dandan; Liang, Jing; Zhang, Yu; Gui, Bin; Wang, Feng; Yi, Xia; Sun, Luyang; Yao, Zhi; Shang, Yongfeng

2012-01-01

Apoptosis-inducing factor (AIF) is a caspase-independent death effector. Normally residing in the mitochondrial intermembrane space, AIF is released and translocated to the nucleus in response to proapoptotic stimuli. Nuclear AIF binds to DNA and induces chromatin condensation and DNA fragmentation, characteristics of apoptosis. Until now, it remained to be clarified how the mitochondrial-nuclear translocation of AIF is regulated. Here we report that steroid receptor coactivator-interacting protein (SIP) interacts directly with AIF in mitochondria and specifically inhibits caspase-independent and AIF-dependent apoptosis. Challenging cells with apoptotic stimuli leads to rapid degradation of SIP, and subsequently AIF is liberated from mitochondria and translocated to the nucleus to induce apoptosis. Together, our data demonstrate that SIP is a novel regulator in caspase-independent and AIF-mediated apoptosis. PMID:22371500

The effects of substance P on histamine and 5-hydroxytryptamine release in the rat

PubMed Central

Fewtrell, C. M. S.; Foreman, J. C.; Jordan, C. C.; Oehme, P.; Renner, H.; Stewart, J. M.

1982-01-01

1. Substance P (SP) induces histamine release from isolated rat peritoneal mast cells at concentrations of 0·1-10 μM. 2. Inhibitors of glycolysis and oxidative phosphorylation prevent the release of histamine induced by SP. 3. Cells heated to 47 °C for 20 min release histamine when treated with an agent causing cell lysis but fail to release in response to SP. 4. SP does not release histamine by interacting with cell-bound IgE. 5. Histamine release by SP is rapid, with more than 90% of the response occurring within 1 min of the addition of the peptide to mast cells at 37 °C. 6. Substance P, unlike antigen—antibody or compound 48/80, does not show enhanced release of histamine when calcium (0·1-1 mM) is present in the extracellular medium but calcium increases the response to SP when the ion is added after the peptide. Extracellular calcium (0·1-1 mM), magnesium (1-10 mM) and cobalt (0·01-0·1 mM) all inhibit SP-induced histamine release when added before the peptide. Pre-treatment of the cells with EDTA (10 mM) and washing in calcium-free medium inhibits the histamine release induced by SP. 7. Histamine release induced by SP was optimum at an extracellular pH of 7·2. 8. A number of peptides structurally related to SP were examined for histamine-releasing activity. At the concentrations tested, the N-terminal dipeptides Lys-Pro and Arg-Pro, tuftsin, physalaemin, eledoisin, SP3-11, SP4-11 and [p-Glu6, p-amino Phe7]-SP6-11 were all found to be inactive. The relative activities of the other peptides were: [Formula: see text] 9. Rat basophilic leukaemia cells (RBL-2H3) fail to respond to SP at concentrations which activate rat mast cells. Release of 5-hydroxytryptamine by immunological activation of RBL cells is not changed by the presence of SP. 10. The mechanism of action of SP on mast cells and the nature of the SP receptor on mast cells is discussed in relation to SP receptors in other cell types. PMID:6184468

Involvement of purinergic receptors and NOD-like receptor-family protein 3-inflammasome pathway in the adenosine triphosphate-induced cytokine release from macrophages.

PubMed

Gicquel, Thomas; Victoni, Tatiana; Fautrel, Alain; Robert, Sacha; Gleonnec, Florence; Guezingar, Marie; Couillin, Isabelle; Catros, Véronique; Boichot, Elisabeth; Lagente, Vincent

2014-04-01

Adenosine triphosphate (ATP) has been described as a danger signal activating the NOD-like receptor-family protein 3 (NLRP3)-inflammasome leading to the pro-inflammatory cytokine, interleukin (IL)-1β, release in the lung. The NLRP3-inflammasome pathway has been previously described to be involved in experimental collagen deposition and the development of pulmonary fibrosis. The aim of the present study was to investigate the role of the NLRP3 inflammasome pathway and P2X7 purinergic receptor in the activation of human macrophages in vitro by ATP. We showed that adenosine 5'-[γ-thio]triphosphate tetralithium salt (ATPγS) and 2',3'-O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzATP), two stable analogs of ATP, are able to potentiate the release of IL-1β from human monocyte-derived macrophages induced by low concentration of lipopolysaccharide (LPS). However, in the same conditions no increase in IL-1α and IL-6 was observed. Immunochemistry has shown that human macrophages natively express NLRP3 and purinergic P2X7 receptors (P2X7 R). NLRP3 and IL-1β mRNA expression were induced from LPS-primed macrophages, but also after 5-h treatment of BzATP as analysed by reverse transcription quantitative polymerase chain reaction. However, other inflammasome pathways (NLRP1, NLRP2, NLRC4, NLRP6 and AIM2) and P2X7 R were not induced by BzATP. We observed that P2X7 R antagonists, A-438079 and A-740003, were able to reduce the release of IL-1β, but not of IL-1α and IL-6 from macrophages stimulated by ATPγS or BzATP. The present results showed the involvement of the P2X7 R-NLRP3 inflammasome pathway in the secretion of IL-1β from ATP-stimulated human macrophages, and suggest that P2X7 R were not involved in IL-1α and IL-6 release. This study also points out that repression of the P2X7 R represents a novel potential therapeutic approach to control fibrosis in lung injury. © 2014 Wiley Publishing Asia Pty Ltd.

Trimethyltin-activated cyclooxygenase stimulates tumor necrosis factor-alpha release from glial cells through reactive oxygen species.

PubMed

Viviani, B; Corsini, E; Pesenti, M; Galli, C L; Marinovich, M

2001-04-15

Exposure of a primary culture of glial cells to the classical neurotoxicant trimethyltin (TMT) results in the release of prostaglandin (PG)E(2) and tumor necrosis factor (TNF)-alpha. Prior treatment of glial cells with either the nonspecific inhibitor of cyclooxygenase and lypoxygenase eicosatetraynoic acid (ETYA) or the cyclooxygenase inhibitor indomethacin completely prevented TMT-induced PGE(2) production and TNF-alpha release, suggesting a role for cyclooxygenase metabolites in TMT-induced TNF-alpha release. Exposure of glial cells to increasing concentrations of PGE(2) or other prostanoids did not increase TNF-alpha synthesis, while the presence of exogenous PGE(2) during treatment of glial cells with TMT actually suppressed TNF-alpha release. The activation of arachidonic acid metabolism produces reactive oxygen species (ROS). Scavenging of ROS by means of the antioxidant trolox prevented the TMT-induced release of TNF-alpha from glial cells, while indomethacin was found to suppress ROS formation induced by 1 microM TMT in glial cells. These results suggest that activation of arachidonic acid metabolism causes TNF-alpha release through the production of ROS rather than PGE(2). Indeed, PGE(2) may exert negative feedback on the release of TNF-alpha. Copyright 2001 Academic Press.

Glutamate-mediated excitotoxicity in neonatal hippocampal neurons is mediated by mGluR-induced release of Ca++ from intracellular stores and is prevented by estradiol

PubMed Central

Hilton, Genell D.; Nunez, Joseph L.; Bambrick, Linda; Thompson, Scott M.; McCarthy, Margaret M.

2008-01-01

Hypoxic/ischemic (HI) brain injury in newborn full-term and premature infants is a common and pervasive source of life time disabilities in cognitive and locomotor function. In the adult, HI induces glutamate release and excitotoxic cell death dependent on NMDA receptor activation. In animal models of the premature human infant, glutamate is also released following HI, but neurons are largely insensitive to NMDA or AMPA/kainic acid (KA) receptor-mediated damage. Using primary cultured hippocampal neurons we have determined that glutamate increases intracellular calcium much more than kainic acid. Moreover, glutamate induces cell death by activating Type I metabotropic glutamate receptors (mGluRs). Pretreatment of neurons with the gonadal steroid estradiol reduces the level of the Type I metabotropic glutamate receptors and completely prevents cell death, suggesting a novel therapeutic approach to excitotoxic brain damage in the neonate. PMID:17156362

Altered neurotransmitter release, vesicle recycling and presynaptic structure in the pilocarpine model of temporal lobe epilepsy

PubMed Central

Upreti, Chirag; Otero, Rafael; Partida, Carlos; Skinner, Frank; Thakker, Ravi; Pacheco, Luis F.; Zhou, Zhen-yu; Maglakelidze, Giorgi; Velíšková, Jana; Velíšek, Libor; Romanovicz, Dwight; Jones, Theresa; Stanton, Patric K.

2012-01-01

In searching for persistent seizure-induced alterations in brain function that might be causally related to epilepsy, presynaptic transmitter release has relatively been neglected. To measure directly the long-term effects of pilocarpine-induced status epilepticus on vesicular release and recycling in hippocampal mossy fibre presynaptic boutons, we used (i) two-photon imaging of FM1-43 vesicular release in rat hippocampal slices; and (ii) transgenic mice expressing the genetically encoded pH-sensitive fluorescent reporter synaptopHluorin preferentially at glutamatergic synapses. In this study we found that, 1–2 months after pilocarpine-induced status epilepticus, there were significant increases in mossy fibre bouton size, faster rates of action potential-driven vesicular release and endocytosis. We also analysed the ultrastructure of rat mossy fibre boutons using transmission electron microscopy. Pilocarpine-induced status epilepticus led to a significant increase in the number of release sites, active zone length, postsynaptic density area and number of vesicles in the readily releasable and recycling pools, all correlated with increased release probability. Our data show that presynaptic release machinery is persistently altered in structure and function by status epilepticus, which could contribute to the development of the chronic epileptic state and may represent a potential new target for antiepileptic therapies. PMID:22344585

Modulating dopamine release by optogenetics in transgenic mice reveals terminal dopaminergic dynamics

PubMed Central

Lu, Yao; Driscoll, Nicolette; Ozden, Ilker; Yu, Zeyang; Nurmikko, Arto V.

2015-01-01

Abstract. Dopamine (DA) release and uptake dynamics in the nucleus accumbens (NAc) have important implications for neurological diseases and mammalian animal behaviors. We demonstrate here the use of cell-type-specific optogenetic targeting in conjunction with fast-scan cyclic voltammetry applied to brain slices prepared from specifically tailored transgenic mice, which conditionally express channelrhodopsin-2 (ChR2) through dopamine transporter (DAT)-Cre. Terminal dopaminergic dynamics and the direct manipulation of induced DA release level by controlling light intensity, pulse width, and the shape of stimulation waveforms were studied. Effective cell terminal-targeting optogenetic induction of DA release at physiological levels in NAc is demonstrated and discussed. It was found that delivering more light energy by increasing stimulation intensity and length is not the only way to control DA release; the temporal shape of the stimulus waveform at light onset is also critically related to induced DA concentrations. In addition, DA uptake dynamics as well as the recovery of the presynaptic releasable DA pool are studied and modeled. More broadly, our experimental findings provide important further evidence for effectively applying optogenetics to induce neurotransmitter release in the behaviorally relevant region of the brain in a highly cell-type selective context. PMID:26171413

Social Laughter Triggers Endogenous Opioid Release in Humans.

PubMed

Manninen, Sandra; Tuominen, Lauri; Dunbar, Robin I; Karjalainen, Tomi; Hirvonen, Jussi; Arponen, Eveliina; Hari, Riitta; Jääskeläinen, Iiro P; Sams, Mikko; Nummenmaa, Lauri

2017-06-21

The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [ 11 C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold-a proxy of endogenous opioidergic activation-was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds. SIGNIFICANCE STATEMENT Social contacts are vital to humans. The size of human social networks significantly exceeds the network that can be maintained by social grooming in other primates. Here, we used PET to show that endogenous opioid release after social laughter may provide a neurochemical mechanism supporting long-term relationships in humans. Participants were scanned twice: after a 30 min social laughter session and after spending 30 min alone in the testing room (baseline). Endogenous opioid release was stronger after laughter versus the

Rainfall-Induced Release of Fecal Coliforms and Other Manure Constituents: Comparison and Modeling▿

PubMed Central

Guber, A. K.; Shelton, D. R.; Pachepsky, Y. A.; Sadeghi, A. M.; Sikora, L. J.

2006-01-01

Modeling release of fecal coliforms is an important component of fate and transport simulations related to environmental water quality. Manure constituents other than fecal coliforms may serve as natural tracers of fecal contamination provided that their release from manure to runoff is similar to the fecal coliform release. The objectives of this work were to compare release of fecal coliforms (FC), chloride (Cl−), organic carbon (OC), and water-soluble phosphorus (P) from dissolving manure and to assess the performance of three models in describing the observed release. Bovine manure was applied on 0.5- by 0.3-m bare and vegetated subplots with 20% slope on sandy loam and clay loam soils. Concentrations of Cl−, FC, OC, and P were measured in runoff collected from troughs at the edges of the subplots at 5-min intervals during 1-h rainfall simulations. The one-parametric exponential model and two-parametric Vadas-Kleinman-Sharpley model and Bradford-Schijven model were fitted to the data. The Bradford-Schijven model had uncorrelated parameters, one of which was linearly related to the irrigation rate, and another parameter reflected the presence or the absence of vegetation. Kinetics of the FC release from manure was similar to the release kinetics of P and OC. The Bradford-Schijven model is recommended to simulate the release of manure constituents. PMID:17028232

Dynamic compression and volatile release of carbonates

NASA Technical Reports Server (NTRS)

Tyburczy, J. A.; Ahrens, T. J.

1984-01-01

Particle velocity profiles upon shock compression and isentropic releases were measured for polycrystalline calcite. The Solenhofen limestone release paths lie, close to the Hugoniot. Calcite 3 to 2 transition, upon release, was observed, but rarefaction shocks were not detected. The equation of state is used to predict the fraction of material devolatilized upon isentropic release as a function of shock pressure. The effect of ambient partial pressure of CO2 on the calculations is demonstrated and considered in models of atmospheric evolution by impact induced mineral devolatilization. The radiative characteristics of shocked calcite indicate that localization of thermal energy occurs under shock compression. Shock entropy calculations result in a minimum estimate of 90% devolatilization upon complete release from 10 GPa. Isentropic release paths from calculated continuum Hugoniot temperatures cross into the CaO (solid) + CO2 (vapor) field at improbably low pressures. It is found that release paths from measured shock temperatures cross into the melt plus vapor field at pressures greater than .5 GPa, which suggests that devolatilization is initiated at the shear banding sites.

IP{sub 3}-dependent intracellular Ca{sup 2+} release is required for cAMP-induced c-fos expression in hippocampal neurons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wenting; Tingare, Asmita; Ng, David Chi-Heng

2012-08-24

Highlights: Black-Right-Pointing-Pointer cAMP-induced c-fos expression in hippocampal neurons requires a submembraneous Ca{sup 2+} pool. Black-Right-Pointing-Pointer The submembraneous Ca{sup 2+} pool derives from intracellular ER stores. Black-Right-Pointing-Pointer Expression of IP{sub 3}-metabolizing enzymes inhibits cAMP-induced c-fos expression. Black-Right-Pointing-Pointer SRE-mediated and CRE-mediated gene expression is sensitive to IP{sub 3}-metabolizing enzymes. Black-Right-Pointing-Pointer Intracellular Ca{sup 2+} release is required for cAMP-induced nuclear translocation of TORC1. -- Abstract: Ca{sup 2+} and cAMP are widely used in concert by neurons to relay signals from the synapse to the nucleus, where synaptic activity modulates gene expression required for synaptic plasticity. Neurons utilize different transcriptional regulators to integrate informationmore » encoded in the spatiotemporal dynamics and magnitude of Ca{sup 2+} and cAMP signals, including some that are Ca{sup 2+}-responsive, some that are cAMP-responsive and some that detect coincident Ca{sup 2+} and cAMP signals. Because Ca{sup 2+} and cAMP can influence each other's amplitude and spatiotemporal characteristics, we investigated how cAMP acts to regulate gene expression when increases in intracellular Ca{sup 2+} are buffered. We show here that cAMP-mobilizing stimuli are unable to induce expression of the immediate early gene c-fos in hippocampal neurons in the presence of the intracellular Ca{sup 2+} buffer BAPTA-AM. Expression of enzymes that attenuate intracellular IP{sub 3} levels also inhibited cAMP-dependent c-fos induction. Synaptic activity induces c-fos transcription through two cis regulatory DNA elements - the CRE and the SRE. We show here that in response to cAMP both CRE-mediated and SRE-mediated induction of a luciferase reporter gene is attenuated by IP{sub 3} metabolizing enzymes. Furthermore, cAMP-induced nuclear translocation of the CREB coactivator TORC1 was

Volume-dependent ATP-conductive large-conductance anion channel as a pathway for swelling-induced ATP release.

PubMed

Sabirov, R Z; Dutta, A K; Okada, Y

2001-09-01

In mouse mammary C127i cells, during whole-cell clamp, osmotic cell swelling activated an anion channel current, when the phloretin-sensitive, volume-activated outwardly rectifying Cl(-) channel was eliminated. This current exhibited time-dependent inactivation at positive and negative voltages greater than around +/-25 mV. The whole-cell current was selective for anions and sensitive to Gd(3)+. In on-cell patches, single-channel events appeared with a lag period of approximately 15 min after a hypotonic challenge. Under isotonic conditions, cell-attached patches were silent, but patch excision led to activation of currents that consisted of multiple large-conductance unitary steps. The current displayed voltage- and time-dependent inactivation similar to that of whole-cell current. Voltage-dependent activation profile was bell-shaped with the maximum open probability at -20 to 0 mV. The channel in inside-out patches had the unitary conductance of approximately 400 pS, a linear current-voltage relationship, and anion selectivity. The outward (but not inward) single-channel conductance was suppressed by extracellular ATP with an IC(50) of 12.3 mM and an electric distance (delta) of 0.47, whereas the inward (but not outward) conductance was inhibited by intracellular ATP with an IC(50) of 12.9 mM and delta of 0.40. Despite the open channel block by ATP, the channel was ATP-conductive with P(ATP)/P(Cl) of 0.09. The single-channel activity was sensitive to Gd(3)+, SITS, and NPPB, but insensitive to phloretin, niflumic acid, and glibenclamide. The same pharmacological pattern was found in swelling-induced ATP release. Thus, it is concluded that the volume- and voltage-dependent ATP-conductive large-conductance anion channel serves as a conductive pathway for the swelling-induced ATP release in C127i cells.

The fast release of sticky protons: Kinetics of substrate binding and proton release in a multidrug transporter

PubMed Central

Adam, Yoav; Tayer, Naama; Rotem, Dvir; Schreiber, Gideon; Schuldiner, Shimon

2007-01-01

EmrE is an Escherichia coli H+-coupled multidrug transporter that provides a unique experimental paradigm because of its small size and stability, and because its activity can be studied in detergent solution. In this work, we report a study of the transient kinetics of substrate binding and substrate-induced proton release in EmrE. For this purpose, we measured transient changes in the tryptophan fluorescence upon substrate binding and the rates of substrate-induced proton release. The fluorescence of the essential and fully conserved Trp residue at position 63 is sensitive to the occupancy of the binding site with either protons or substrate. The maximal rate of binding to detergent-solubilized EmrE of TPP+, a high-affinity substrate, is 2 × 107 M−1·s−1, a rate typical of diffusion-limited reactions. Rate measurements with medium- and low-affinity substrates imply that the affinity is determined mainly by the koff of the substrate. The rates of substrate binding and substrate-induced release of protons are faster at basic pHs and slower at lower pHs. These findings imply that the substrate-binding rates are determined by the generation of the species capable of binding; this is controlled by the high affinity to protons of the glutamate at position 14, because an Asp replacement with a lower pK is faster at the same pHs. PMID:17984053

The 2-monoacylglycerol moiety of dietary fat appears to be responsible for the fat-induced release of GLP-1 in humans.

PubMed

Mandøe, Mette J; Hansen, Katrine B; Hartmann, Bolette; Rehfeld, Jens F; Holst, Jens J; Hansen, Harald S

2015-09-01

Dietary triglycerides can, after digestion, stimulate the intestinal release of incretin hormones through activation of G protein-coupled receptor (GPR) 119 by 2-monoacylglycerol and by the activation of fatty acid receptors for long- and short-chain fatty acids. Medium-chain fatty acids do not stimulate the release of intestinal hormones. To dissect the mechanism of fat-induced glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) release in humans, we compared the effects of tributyrin (containing short-chain fatty acids; i.e., butyric acid), olive oil [containing long-chain fatty acids; e.g., oleic acid plus 2-oleoyl glycerol (2-OG)], and 1,3-dioctanoyl-2-oleoyl glycerol (C8-dietary oil), which is digested to form medium-chain fatty acids : i.e., octanoic acid : and 2-OG. In a randomized, single-blinded crossover study, 12 healthy white men [mean age: 24 y; BMI (in kg/m(2)): 22] were given the following 4 meals on 4 different days: 200 g carrots + 6.53 g tributyrin, 200 g carrots + 13.15 g C8-dietary oil, 200 g carrots + 19 g olive oil, or 200 g carrots. All of the lipids totaled 0.0216 mol. Main outcome measures were incremental areas under the curve for total GLP-1, GIP, and cholecystokinin (CCK) in plasma. C8-dietary oil and olive oil showed the same GLP-1 response [583 ± 101 and 538 ± 71 (pmol/L) × 120 min; P = 0.733], whereas the GIP response was higher for olive oil than for C8-dietary oil [3293 ± 404 and 1674 ± 270 (pmol/L) × 120 min; P = 0.002]. Tributyrin and carrots alone resulted in no increase in any of the measured hormones. Peptide YY (PYY) and neurotensin responses resembled those of GLP-1. Only olive oil stimulated CCK release. Under our study conditions, 2-OG and GPR119 activation can fully explain the olive oil-induced secretion of GLP-1, PYY, and neurotensin. In contrast, both oleic acid and 2-OG contributed to the GIP response. Dietary butyrate did not stimulate gut hormone secretion. Olive oil

Secreted and intracellular phospholipases A2 inhibition by 1-decyl 2-octyl-glycerophosphocholine in rat peritoneal macrophages.

PubMed

Boucrot, P; Bobin-Dubigeon, C; Elkihel, L; Letourneux, Y; Jugé, M; Gandemer, G; Petit, J Y

1998-01-01

Compounds able to inhibit phospholipases A2 can be considered as potential anti-inflammatory drugs. In this respect, the inhibitory effect of the phospholipid analogue 1-decyl 2-octyl-rac-glycero-3-phosphocholine (decyloctyl-GPC) added to the culture medium of rat peritoneal macrophages stimulated with ionophore A23187 was determined. (a) The substrate of phospholipase A2 1-octadecanoyl 2-[14C]eicosatetraenoyl-sn-glycero-3-phosphocholine ([14C]20:4-GPC) was added to the culture medium. In macrophages + extracellular fluids, its hydrolysis at the 2-position, produced [14C]non-phosphorous lipids which reached 12% of the dose at 0.14 microM, 73% at 0.9 and > 90% at 1.6 microM; in experiments where macrophages and extracellular fluids were analyzed separately, decyloctyl-GPC initially added at 4 microM, significantly inhibited the release of [14C]fatty acids and the eicosanoid synthesis, demonstrating its ability to inhibit secreted and/or intracellular phospholipases A2. (b) Extracellular fluids were separated from the macrophages and incubated with [14C]20:4-GPC: 48% of the dose was hydrolyzed by extracellular fluid-associated secreted phospholipase A2 and decyloctyl-GPC at 3 microM, reduced this hydrolysis by 50%. (c) [3H]arachidonic acid ([3H]20:4) was added to the culture medium and was esterified in the macrophage membrane phospholipids. Activation of intracellular phospholipase A2 induced the release of [3H] fatty acids and eicosanoid synthesis. These releases were inhibited by 50% with decyloctyl-GPC added at 4 microM. (d) [3H]20:4 and [14C]20:4-GPC were added to the culture medium of the macrophages. [3H] and [14C] fatty acids and eicosanoids were released in macrophages or extracellular fluids. They were significantly reduced by the phospholipid analogue added at 4 microM. It is concluded that secreted and intracellular phospholipases A2 were both inhibited by decyloctyl-GPC which extensively reduced the 20:4 release from exogenous and membrane phospholipids

Local injections of corticotropin releasing factor reduce doxorubicin-induced acute inflammation in the eyelid.

PubMed

McLoon, L K; Wirtschafter, J

1997-04-01

permeability. Corticotropin releasing factor and doxorubicin cotreatments delayed the onset of skin injury and decreased the total duration of injury to the skin compared to doxorubicin alone. The effectiveness of doxorubicin chemomyectomy was maintained; muscle loss was significant at all doses of CRF combined with doxorubicin. Corticotropin releasing factor dramatically decreased the acute inflammatory reaction that results in the eyelid from local doxorubicin injections. Not only did CRF reduce the acute influx of monocytes and macrophages, but it protected the skin overlying the injection site, substantially reducing the extent of skin injury. The efficacy of doxorubicin-induced muscle toxicity was maintained. A treatment protocol that combines myotoxicity with antiinflammatory activity in the treated eyelids may lead to a more effective patient treatment by increasing patient acceptance. The potential should be explored that CRF may be of clinical use in limiting tissue injury when administered immediately after extravasation during cancer chemotherapy.

The free-radical scavenger, edaravone, augments NO release from vascular cells and platelets after laser-induced, acute endothelial injury in vivo.

PubMed

Yamashita, T; Shoge, M; Oda, E; Yamamoto, Y; Giddings, J C; Kashiwagi, S; Suematsu, M; Yamamoto, J

2006-05-01

In vitro and in vivo experimental models have demonstrated that vascular endothelial function is significantly impaired as a result of oxidative stress, mediated by the generation of oxygen-derived free radicals in response to chronic or acute inflammation. In particular, super-oxide () at specific concentrations leads to the impairment of nitric oxide (NO) bioactivity, and it is known that NO plays a fundamental role in the maintenance of vascular homeostasis. The relationship between reactive oxygen species (ROS) and NO release in thrombosis-related endothelial damage in the peripheral microvasculature remains unclear, however. The purpose of the present study was to investigate the effect of the free-radical scavenger, edaravone, on NO synthesis and thrombotic potential in arterioles after exposure to laser irradiation. Highly sensitive electrochemical NO microsensors were positioned in femoral arterioles of mice, and the kinetics of NO release were recorded in response to standardized laser irradiation in vivo. In addition, images of NO release from damaged vascular cells were investigated in a similar rat model using the NO-sensitive dye 4,5-diaminofluorescein diacetate (DAF-2DA). Thrombogenesis was assessed in carotid arterioles by continuous video microscopy using image analysis software. Laser irradiation led to NO release from perturbed endothelial cells and from platelet-rich thrombi. Edaravone had no significant effect on NO release in non-laser treated, intact endothelium compared with placebo. In contrast, edaravone demonstrated a dose-dependent effect on NO release and thrombogenicity. At a concentration of 10.5 mg/kg per h, edaravone promoted a 5-fold increase in NO and a reduction in platelet-rich thrombus volume to 58% of the placebo values. Our data provide direct evidence to confirm that acute endothelial damage in peripheral microvessels initially induces NO release and that the free-radical scavenger, edaravone, augments NO synthesis leading to

Ca2+-mediated ascorbate release from coronary artery endothelial cells.

PubMed

Davis, Kim A; Samson, Sue E; Best, Kelly; Mallhi, Kanwaldeep K; Szewczyk, Magdalena; Wilson, John X; Kwan, Chiu-Yin; Grover, Ashok K

2006-01-01

1.--The addition of Ca(2+) ionophore A23187 or ATP to freshly isolated or cultured pig coronary artery endothelial cells (PCEC) potentiated the release of ascorbate (Asc). Cultured PCEC were used to characterize the Ca(2+)-mediated release. An increase in Ca(2+)-mediated Asc release was observed from PCEC preincubated with Asc, Asc-2-phosphate or dehydroascorbic acid (DHAA). 2.--The effects of various ATP analogs and inhibition by suramin were consistent with the ATP-induced release being mediated by P2Y2-like receptors. 3.--ATP-stimulated Asc release was Ca(2+)-mediated because (a) ATP analogs that increased Asc release also elevated cytosolic [Ca(2+)], (b) Ca(2+) ionophore A23187 and cyclopiazonic acid stimulated the Asc release, (c) removing extracellular Ca(2+) and chelating intracellular Ca(2+)inhibited the ATP-induced release, and (d) inositol-selective phospholipase C inhibitor U73122 also inhibited this release. 4.--Accumulation of Asc by PCEC was examined at Asc concentrations of 10 microM (Na(+)-Asc symporter not saturated) and 5 mM (Na(+)-Asc symporter saturated). At 10 microM Asc, A23187 and ATP caused an inhibition of Asc accumulation but at 5 mM Asc, both the agents caused a stimulation. Substituting gluconate for chloride did not affect the basal Asc uptake but it abolished the effects of A23187. 5.--PCEC but not pig coronary artery smooth muscle cells show a Ca(2+)- mediated Asc release pathway that may be activated by agents such as ATP.

Tryptophan availability modulates serotonin release from rat hypothalamic slices

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1989-01-01

The relationship between the tryptophan availability and serononin release from rat hypothalamus was investigated using a new in vitro technique for estimating rates at which endogenous serotonin is released spontaneously or upon electrical depolarization from hypothalamic slices superfused with a solution containing various amounts of tryptophan. It was found that the spontaneous, as well as electrically induced, release of serotonin from the brain slices exhibited a dose-dependent relationship with the tryptophan concentration of the superfusion medium.

Familiar companions diminish cocaine conditioning and attenuate cocaine-stimulated dopamine release in the nucleus accumbens.

PubMed

Tzeng, Wen-Yu; Cherng, Chian-Fang G; Wang, Shyi-Wu; Yu, Lung

2016-06-01

This study aimed to assess the impact of companions on the rewarding effects of cocaine. Three cage mates, serving as companions, were housed with each experimental mouse throughout cocaine-place conditioning in a cocaine-induced conditioned place preference (CPP) paradigm using conditioning doses of 10 and 20mg/kg. The presence of companions decreased the magnitude of the CPP. At 20mg/kg, cocaine stimulated dopamine (DA) release in the nucleus accumbens as evidenced by a significant decrease in total (spontaneous and electrical stimulation-provoked) DA release in accumbal superfusate samples. The presence of companions prevented this cocaine-stimulated DA release; such a reduction in cocaine-induced DA release may account for the reduction in the magnitude of the CPP in the presence of the companions. Furthermore, cocaine pretreatment (2.5mg/kg) was found to prevent the companion-produced decreases in cocaine (10mg/kg/conditioning)-induced CPP as well as the cocaine (10mg/kg)-stimulated DA release. Moreover, the presence of methamphetamine (MA) (1mg/kg)-treated companions decreased cocaine (20mg/kg/conditioning)-induced CPP and prevented the cocaine (20mg/kg)-stimulated DA release. Finally, the presence of companions decreased the magnitude of the CPP could not seem to be accounted for by cocaine-stimulated corticosterone (CORT) release. Taken together, these results indicate that familiar companions, regardless of their pharmacological status, may exert dampening effects on CPP induced by moderate to high conditioning doses of cocaine, at least in part, by preventing cocaine-stimulated DA release in the nucleus accumbens. Copyright © 2016 Elsevier B.V. All rights reserved.

Involvement of reactive oxygen species in brominated diphenyl ether-47-induced inflammatory cytokine release from human extravillous trophoblasts in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Hae-Ryung, E-mail: heaven@umich.edu; Kamau, Patricia W.; Loch-Caruso, Rita

2014-01-15

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds. Brominated diphenyl ether (BDE)-47 is one of the most prevalent PBDE congeners found in human breast milk, serum and placenta. Despite the presence of PBDEs in human placenta, effects of PBDEs on placental cell function are poorly understood. The present study investigated BDE-47-induced reactive oxygen species (ROS) formation and its role in BDE-47-stimulated proinflammatory cytokine release in a first trimester human extravillous trophoblast cell line, HTR-8/SVneo. Exposure of HTR-8/SVneo cells for 4 h to 20 μM BDE-47 increased ROS generation 1.7 fold as measured by the dichlorofluorescein (DCF) assay. Likewise,more » superoxide anion production increased approximately 5 fold at 10 and 15 μM and 9 fold at 20 μM BDE-47 with a 1-h exposure, as measured by cytochrome c reduction. BDE-47 (10, 15 and 20 μM) decreased the mitochondrial membrane potential by 47–64.5% at 4, 8 and 24 h as assessed with the fluorescent probe Rh123. Treatment with 15 and 20 μM BDE-47 stimulated cellular release and mRNA expression of IL-6 and IL-8 after 12 and 24-h exposures: the greatest increases were a 35-fold increased mRNA expression at 12 h and a 12-fold increased protein concentration at 24 h for IL-6. Antioxidant treatments (deferoxamine mesylate, (±)α-tocopherol, or tempol) suppressed BDE-47-stimulated IL-6 release by 54.1%, 56.3% and 37.7%, respectively, implicating a role for ROS in the regulation of inflammatory pathways in HTR-8/SVneo cells. Solvent (DMSO) controls exhibited statistically significantly decreased responses compared with non-treated controls for IL-6 release and IL-8 mRNA expression, but these responses were not consistent across experiments and times. Nonetheless, it is possible that DMSO (used to dissolve BDE-47) may have attenuated the stimulatory actions of BDE-47 on cytokine responses. Because abnormal activation of proinflammatory responses can disrupt trophoblast

Streptococcus sanguinis-induced cytokine and matrix metalloproteinase-1 release from platelets.

PubMed

Cognasse, Fabrice; Hamzeh-Cognasse, Hind; Chabert, Adrien; Jackson, Elke; Arthaud, Charles-Antoine; Garraud, Olivier; McNicol, Archie

2014-04-22

Streptococcus sanguinis (S.sanguinis), a predominant bacterium in the human oral cavity, has been widely associated with the development of infective endocarditis. Platelets play both a haemostatic function and can influence both innate and adaptive immune responses. Previous studies have shown that S.sanguinis can interact with, and activate, platelets. The aim of this study was to determine whether S.sanguinis stimulates the release of matrix metalloproteinases (MMPs) 1, 2 and 9 and the pro-inflammatory mediators SDF-1, VEGF and sCD40L, from platelets and to subsequently pharmacologically address the release mechanism (s). S.sanguinis stimulated the release of MMP-1, SDF-1, VEGF and sCD40L from platelets and inhibitors of cyclooxygenase and phosphatidylinositol 3-kinase, and antagonists of the αIIbβ3 integrin and glycoprotein Ib, each inhibited the secretion of all factors. Therefore the release of MMP-1, SDF-1, VEGF and sCD40L occurs late in the platelet response to S.sanguinis and highlights the complex intracellular signalling pathways stimulated in response to S.sanguinis which lead to haemostasis, MMP and pro-inflammatory mediator secretion.

Streptococcus sanguinis-induced cytokine and matrix metalloproteinase-1 release from platelets

PubMed Central

2014-01-01

Background Streptococcus sanguinis (S.sanguinis), a predominant bacterium in the human oral cavity, has been widely associated with the development of infective endocarditis. Platelets play both a haemostatic function and can influence both innate and adaptive immune responses. Previous studies have shown that S.sanguinis can interact with, and activate, platelets. Results The aim of this study was to determine whether S.sanguinis stimulates the release of matrix metalloproteinases (MMPs) 1, 2 and 9 and the pro-inflammatory mediators SDF-1, VEGF and sCD40L, from platelets and to subsequently pharmacologically address the release mechanism (s). S.sanguinis stimulated the release of MMP-1, SDF-1, VEGF and sCD40L from platelets and inhibitors of cyclooxygenase and phosphatidylinositol 3-kinase, and antagonists of the αIIbβ3 integrin and glycoprotein Ib, each inhibited the secretion of all factors. Conclusions Therefore the release of MMP-1, SDF-1, VEGF and sCD40L occurs late in the platelet response to S.sanguinis and highlights the complex intracellular signalling pathways stimulated in response to S.sanguinis which lead to haemostasis, MMP and pro-inflammatory mediator secretion. PMID:24755160

Transient ischemia reduces norepinephrine release during sustained ischemia. Neural preconditioning in isolated rat heart.

PubMed

Seyfarth, M; Richardt, G; Mizsnyak, A; Kurz, T; Schömig, A

1996-04-01

Endogenous catecholamine release may play a role in ischemic preconditioning either as a trigger or as a target within the process of myocardial preconditioning. Therefore, we investigated the effect of transient ischemia (TI) on norepinephrine release during sustained ischemia in isolated rat hearts. TI was induced by multiple cycles of global ischemia followed by reperfusion with a duration of 5 minutes each, comparable to ischemic preconditioning protocols. After TI, norepinephrine release was evoked by either sustained global ischemia, anoxia, cyanide intoxication, tyramine, or electrical stimulation. During TI, no washout of norepinephrine was observed, and tissue concentrations of norepinephrine were not changed. TI, however, reduced norepinephrine overflow after 20 minutes of sustained ischemia from 239 +/- 26 pmol/g (control) to 79+/-8 pmol/g (67% reduction, P <.01 ). A similar reduction of ischemia-induced norepinephrine release from 192 +/- 22 pmol/g (control) to 90 +/- 15 pmol/g was observed when hearts underwent transient anoxia without glucose (P < .05). When reperfusion between TI and sustained ischemia was prolonged from 5 to 90 minutes, the inhibitory effect of TI on norepinephrine release was gradually lost. Susceptibility to TI was a unique feature of norepinephrine release induced by sustained ischemia, since release of norepinephrine evoked by anoxia, cyanide intoxication, tyramine, or electrical stimulation remained unaffected by TI. We propose a protective effect of TI on neural tissue, which may reduce norepinephrine-induced damage during prolonged myocardial ischemia.

Zoledronate and ion-releasing resins impair dentin collagen degradation.

PubMed

Tezvergil-Mutluay, A; Seseogullari-Dirihan, R; Feitosa, V P; Tay, F R; Watson, T F; Pashley, D H; Sauro, S

2014-10-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. © International & American Associations for Dental Research.

ACTH releasing activity of KP-102 (GHRP-2) in rats is mediated mainly by release of CRF.

PubMed

Hirotani, Chiharu; Oki, Yutaka; Ukai, Kiyoharu; Okuno, Tadashi; Kurasaki, Shigeru; Ohyama, Tadashi; Doi, Naomi; Sasaki, Ken; Ase, Katsuhiko

2005-01-01

KP-102 (GHRP-2: pralmorelin) is a synthetic growth hormone releasing peptide (GHRP) that powerfully stimulates the release of GH by acting (i.v.) at both hypothalamic and pituitary sites. Intravenous (i.v.) administration of KP-102 also elicits slight but significant release of adrenocorticotropic hormone (ACTH) in both animals and humans, as is seen with other GHRPs. GHRPs are thought to stimulate the hypothalamic-pituitary-adrenal axis by releasing endogenous ACTH secretagogues such as arginine vasopressin (AVP) and/or corticotropin releasing factor (CRF), though neither AVP nor CRF has been shown clearly to be involved significantly in GHRP-evoked ACTH release. In the present study, we investigated the effects of KP-102 on ACTH release in conscious rats under improved experimental conditions that minimized the influence of stress. Administration of KP-102 i.v. increased plasma ACTH significantly, but did not stimulate ACTH release from rat primary pituitary cells. Administration of KP-102 together with either AVP or CRF elicited significantly greater increases in plasma ACTH levels than any of the agonists alone. Notably, the combination of KP-102 and AVP produced a much greater increase in ACTH than KP-102 plus CRF, indicating that KP-102 augments the effect of exogenous CRF only weakly. Conversely, a CRF antagonist markedly inhibited KP-102-induced ACTH release in conscious rats, whereas an AVP antagonist or anti-AVP antiserum did not. Taken together, these findings suggest that KP-102 acts via the hypothalamus to stimulate ACTH release in rats, and that these effects are mediated mainly by the release of CRF.

Effect of the hexane extract of Piper auritum on insulin release from β-cell and oxidative stress in streptozotocin-induced diabetic rat.

PubMed

Gutierrez, Rosa Martha Perez

2012-10-01

The large-leafed perennial plant Piper auritum known as Hoja Santa, is used for its leaves that because of their spicy aromatic scent and flavor have an important presence in Mexican cuisine, and in many regions, this plant is known for its therapeutic properties. In the present study, we investigated the effect of hexane, chloroform and methanol extracts from Piper auritum on cell culture system and the effect in streptozotocin-induced type 1 diabetic rats treated by 28 days on the physiological, metabolic parameters and oxidative stress. The hexane extract of P. auritum (HS) treatment significantly reduced the intake of both food, water and body weight loss as well as levels of blood glucose, serum cholesterol, triglycerides and increase HDL-cholesterol. After 4-week administration of HS antioxidant enzyme as SOD, CAT, GSH, GPx in pancreas were determined. These enzyme increased significantly compared with those of the diabetic rats control and normal animals. For all estimated, the results of HS treated groups leading to a restoration of the defense mechanism. The treatment also improves pancreatic TBARS-reactive substance level and serum NO and iNOS. To determine the insulin releasing activity, after extract treatment the serum and pancreatic sections were processed for examination of insulin-releasing activity using an immunocytochemistry kit. The results showed that administration of the hexane extract (200 and 400 mg/kg) exhibited a significant increase in serum and pancreas tissue insulin. Administration of streptozotocin decreased the insulin secretory activity in comparison with intact rats, but treatment with the HS extract increased significantly the activity of the beta cells in comparison with the diabetic control rats. The extract decreased serum glucose in streptozotocin-induced diabetic rats and increased insulin release from the beta cells of the pancreas. In cultured RIN-5F cells, we examined whether hexane extract of P. auritum would protect the

Effect of the hexane extract of Piper auritum on insulin release from β-cell and oxidative stress in streptozotocin-induced diabetic rat

PubMed Central

Gutierrez, Rosa Martha Perez

2012-01-01

Background: The large-leafed perennial plant Piper auritum known as Hoja Santa, is used for its leaves that because of their spicy aromatic scent and flavor have an important presence in Mexican cuisine, and in many regions, this plant is known for its therapeutic properties. Materials and Methods: In the present study, we investigated the effect of hexane, chloroform and methanol extracts from Piper auritum on cell culture system and the effect in streptozotocin-induced type 1 diabetic rats treated by 28 days on the physiological, metabolic parameters and oxidative stress. Results: The hexane extract of P. auritum (HS) treatment significantly reduced the intake of both food, water and body weight loss as well as levels of blood glucose, serum cholesterol, triglycerides and increase HDL-cholesterol. After 4-week administration of HS antioxidant enzyme as SOD, CAT, GSH, GPx in pancreas were determined. These enzyme increased significantly compared with those of the diabetic rats control and normal animals. For all estimated, the results of HS treated groups leading to a restoration of the defense mechanism. The treatment also improves pancreatic TBARS–reactive substance level and serum NO and iNOS. To determine the insulin releasing activity, after extract treatment the serum and pancreatic sections were processed for examination of insulin-releasing activity using an immunocytochemistry kit. The results showed that administration of the hexane extract (200 and 400 mg/kg) exhibited a significant increase in serum and pancreas tissue insulin. Administration of streptozotocin decreased the insulin secretory activity in comparison with intact rats, but treatment with the HS extract increased significantly the activity of the beta cells in comparison with the diabetic control rats. The extract decreased serum glucose in streptozotocin-induced diabetic rats and increased insulin release from the beta cells of the pancreas. In cultured RIN-5F cells, we examined whether

Oxygen Release Induced Chemomechanical Breakdown of Layered Cathode Materials

DOE PAGES

Mu, Linqin; Lin, Ruoqian; Xu, Rong; ...

2018-04-18

Chemical and mechanical properties interplay on the nanometric scale and collectively govern the functionalities of battery materials. Understanding the relationship between the two can inform the design of battery materials with optimal chemomechanical properties for long-life lithium batteries. Herein, we report a mechanism of nanoscale mechanical breakdown in layered oxide cathode materials, originating from oxygen release at high states of charge under thermal abuse conditions. Here, we observe that the mechanical breakdown of charged Li 1-xNi 0.4Mn 0.4Co 0.2O 2 materials proceeds via a two-step pathway involving intergranular and intragranular crack formation. Owing to the oxygen release, sporadic phase transformationsmore » from the layered structure to the spinel and/or rocksalt structures introduce local stress, which initiates microcracks along grain boundaries and ultimately leads to the detachment of primary particles; i.e., intergranular crack formation. Furthermore, intragranular cracks (pores and exfoliations) form, likely due to the accumulation of oxygen vacancies and continuous phase transformations at the surfaces of primary particles. Finally, finite element modeling confirms our experimental observation that the crack formation is attributable to formation of oxygen vacancies, oxygen release, and phase transformations. This study is designed to directly observe the chemomechanical behavior of layered oxide cathode materials and provides a chemical basis for strengthening primary and secondary particles by stabilizing the oxygen anions in the lattice.« less

Oxygen Release Induced Chemomechanical Breakdown of Layered Cathode Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Linqin; Lin, Ruoqian; Xu, Rong

Chemical and mechanical properties interplay on the nanometric scale and collectively govern the functionalities of battery materials. Understanding the relationship between the two can inform the design of battery materials with optimal chemomechanical properties for long-life lithium batteries. Herein, we report a mechanism of nanoscale mechanical breakdown in layered oxide cathode materials, originating from oxygen release at high states of charge under thermal abuse conditions. Here, we observe that the mechanical breakdown of charged Li 1-xNi 0.4Mn 0.4Co 0.2O 2 materials proceeds via a two-step pathway involving intergranular and intragranular crack formation. Owing to the oxygen release, sporadic phase transformationsmore » from the layered structure to the spinel and/or rocksalt structures introduce local stress, which initiates microcracks along grain boundaries and ultimately leads to the detachment of primary particles; i.e., intergranular crack formation. Furthermore, intragranular cracks (pores and exfoliations) form, likely due to the accumulation of oxygen vacancies and continuous phase transformations at the surfaces of primary particles. Finally, finite element modeling confirms our experimental observation that the crack formation is attributable to formation of oxygen vacancies, oxygen release, and phase transformations. This study is designed to directly observe the chemomechanical behavior of layered oxide cathode materials and provides a chemical basis for strengthening primary and secondary particles by stabilizing the oxygen anions in the lattice.« less

Release-ability of nano fillers from different nanomaterials (toward the acceptability of nanoproduct)

NASA Astrophysics Data System (ADS)

Golanski, L.; Guiot, A.; Pras, M.; Malarde, M.; Tardif, F.

2012-07-01

It is of great interest to set up a reproducible and sensitive method able to qualify nanomaterials before their market introduction in terms of their constitutive nanoparticle release-ability in usage. Abrasion was performed on polycarbonate, epoxy, and PA11 polymers containing carbone nanotubes (CNT) up to 4 %wt. Using Taber linear standard tool and standard abrasion conditions no release from polymer coatings containing CNT was measured. In this study, new practical tools inducing non-standardized stresses able to compete with van der Waals forces were developed and tested on model polymers, showing controlled CNT dispersion. These stresses are still realistic, corresponding to scratching, instantaneous mechanical shocks, and abrasion of the surface. They offer an efficient way to quantify if release is possible from nanomaterials under different mechanical stresses and therefore give an idea about the mechanisms that favors it. Release under mechanical shocks and hard abrasion was obtained using these tools but only when nanomaterials present a bad dispersion of CNT within the epoxy matrix. Under the same conditions no release was obtained from the same material presenting a good dispersion. The CNT used in this study showed an external diameter Dext = 12 nm, an internal diameter Din = 5 nm, and a mean length of 1 μm. Release from paints under hard abrasion using a standard rotative Taber tool was obtained from a intentionaly non-optimized paint containing SiO2 nanoparticles up to 35 %wt. The primary diameter of the SiO2 was estimated to be around 12 nm. A metallic rake was efficient to remove nanoparticles from a non-woven fabric nanomaterial.

Quantitative Protein Sulfenic Acid Analysis Identifies Platelet Releasate-Induced Activation of Integrin β2 on Monocytes via NADPH Oxidase.

PubMed

Li, Ru; Klockenbusch, Cordula; Lin, Liwen; Jiang, Honghui; Lin, Shujun; Kast, Juergen

2016-12-02

Physiological stimuli such as thrombin, or pathological stimuli such as lysophosphatidic acid (LPA), activate platelets. The activated platelets bind to monocytes through P-selectin-PSGL-1 interactions but also release the contents of their granules, commonly called "platelet releasate". It is known that monocytes in contact with platelet releasate produce reactive oxygen species (ROS). Reversible cysteine oxidation by ROS is considered to be a potential regulator of protein function. In a previous study, we used THP-1 monocytic cells exposed to LPA- or thrombin-induced platelet releasate and a modified biotin switch assay to unravel the biological processes that are influenced by reversible cysteine oxidation. To gain a better understanding of the redox regulation of monocytes in atherosclerosis, we have now altered the modified biotin switch to selectively quantify protein sulfenic acid, a subpopulation of reversible cysteine oxidation. Using arsenite as reducing agent in the modified biotin switch assay, we were able to quantify 1161 proteins, in which more than 100 sulfenic acid sites were identified. Bioinformatics analysis of the quantified sulfenic acid sites highlighted the relevant, previously missed biological process of monocyte transendothelial migration, which included integrin β 2 . Flow cytometry validated the activation of LFA-1 (α L β 2 ) and Mac-1 (α M β 2 ), two subfamilies of integrin β 2 complexes, on human primary monocytes following platelet releasate treatment. The activation of LFA-1 was mediated by ROS from NADPH oxidase (NOX) activation. Production of ROS and activation of LFA-1 in human primary monocytes were independent of P-selectin-PSGL-1 interaction. Our results proved the modified biotin switch assay to be a powerful tool with the ability to reveal new regulatory mechanisms and identify new therapeutic targets.

Intracellular sphingosine releases calcium from lysosomes

PubMed Central

Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

2015-01-01

To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC. DOI: http://dx.doi.org/10.7554/eLife.10616.001 PMID:26613410

Activation of microglial cells triggers a release of brain-derived neurotrophic factor (BDNF) inducing their proliferation in an adenosine A2A receptor-dependent manner: A2A receptor blockade prevents BDNF release and proliferation of microglia

PubMed Central

2013-01-01

Background Brain-derived neurotrophic factor (BDNF) has been shown to control microglial responses in neuropathic pain. Since adenosine A2A receptors (A2ARs) control neuroinflammation, as well as the production and function of BDNF, we tested to see if A2AR controls the microglia-dependent secretion of BDNF and the proliferation of microglial cells, a crucial event in neuroinflammation. Methods Murine N9 microglial cells were challenged with lipopolysaccharide (LPS, 100 ng/mL) in the absence or in the presence of the A2AR antagonist, SCH58261 (50 nM), as well as other modulators of A2AR signaling. The BDNF cellular content and secretion were quantified by Western blotting and ELISA, A2AR density was probed by Western blotting and immunocytochemistry and cell proliferation was assessed by BrdU incorporation. Additionally, the A2AR modulation of LPS-driven cell proliferation was also tested in primary cultures of mouse microglia. Results LPS induced time-dependent changes of the intra- and extracellular levels of BDNF and increased microglial proliferation. The maximal LPS-induced BDNF release was time-coincident with an LPS-induced increase of the A2AR density. Notably, removing endogenous extracellular adenosine or blocking A2AR prevented the LPS-mediated increase of both BDNF secretion and proliferation, as well as exogenous BDNF-induced proliferation. Conclusions We conclude that A2AR activation plays a mandatory role controlling the release of BDNF from activated microglia, as well as the autocrine/paracrine proliferative role of BDNF. PMID:23363775

Melatonin inhibits voltage-sensitive Ca(2+) channel-mediated neurotransmitter release.

PubMed

Choi, Tae-Yong; Kwon, Ji Eun; Durrance, Eunice Sung; Jo, Su-Hyun; Choi, Se-Young; Kim, Kyong-Tai

2014-04-04

Melatonin is involved in various neuronal functions such as circadian rhythmicity and thermoregulation. Melatonin has a wide range of pharmacologically effective concentration levels from the nanomolar to millimolar levels. Recently, the antiepileptic effect of high dose melatonin has been the focus of clinical studies; however, its detailed mechanism especially in relation to neurotransmitter release and synaptic transmission remains unclear. We studied the effect of melatonin at high concentrations on the neurotransmitter release by monitoring norepinephrine release in PC12 cells, and excitatory postsynaptic potential in rat hippocampal slices. Melatonin inhibits the 70mM K(+)-induced Ca(2+) increase at millimolar levels without effect on bradykinin-triggered Ca(2+) increase in PC12 cells. Melatonin (1mM) did not affect A2A adenosine receptor-evoked cAMP production, and classical melatonin receptor antagonists did not reverse the melatonin-induced inhibitory effect, suggesting G-protein coupled receptor independency. Melatonin inhibits the 70mM K(+)-induced norepinephrine release at a similar effective concentration range in PC12 cells. We confirmed that melatonin (100µM) inhibits excitatory synaptic transmission of the hippocampal Schaffer collateral pathway with the decrease in basal synaptic transmission and the increase in paired pulse ratio. These results show that melatonin inhibits neurotransmitter release through the blocking of voltage-sensitive Ca(2+) channels and suggest a possible mechanism for the antiepileptic effect of melatonin. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of diltiazem or verapamil on calcium uptake and release from chicken skeletal muscle sarcoplasmic reticulum.

PubMed

Paydar, Mehrak Javadi; Pousti, Abbas; Farsam, Hasan; Amanlou, Massoud; Mehr, Shahram Ejtemaei; Dehpour, Ahmad Reza

2005-11-01

The purpose of this study was to determine the effects of 2 Ca2+ channel blockers, verapamil and diltiazem, on calcium loading (active Ca2+ uptake) and the following Ca2+ release induced by silver ion (Ag+) and Ca2+ from the membrane of heavy sarcoplasmic reticulum (SR) of chicken skeletal muscle. A fluorescent probe technique was employed to determine the calcium movement through the SR. Pretreatment of the medium with diltiazem and verapamil resulted in a significant decrease in the active Ca2+ uptake, with IC50 of about 290 micromol/L for verapamil and 260 micromol/L for diltiazem. Inhibition of Ca2+ uptake was not due to the development of a substantial drug-dependent leak of Ca2+ from the SR. It might, in part, have been mediated by a direct inhibitory effect of these drugs on the Ca2+ ATPase activity of the SR Ca2+ pump. We confirmed that Ca2+ channel blockers, administered after SR Ca2+ loading and before induction of Ca2+ release, caused a dose-dependent inhibition of both Ca2+- and Ag+-induced Ca2+ release rate. Moreover, if Ca2+ channel blockers were administered prior to SR Ca2+ loading, in spite of Ca2+ uptake inhibition the same reduction in Ca2+- and Ag+-induced Ca2+ release rate was seen. We showed that the inhibition of Ag+-induced Ca2+ release by L-channel blockers is more sensitive than Ca2+-induced Ca2+ release inhibition, so the IC50 for Ag+- and Ca2+-induced Ca2+ release was about 100 and 310 micromol/L for verapamil and 79 and 330 micromol/L for diltiazem, respectively. Our results support the evidence that Ca2+ channel blockers affect muscle microsome of chicken skeletal muscle by 2 independent mechanisms: first, reduction of Ca2+ uptake rate and Ca2+-ATPase activity inhibition, and second, inhibition of both Ag+- and Ca2+-induced Ca2+ release by Ca2+ release channels. These findings confirm the direct effect of Ca2+ channel blockers on calcium release channels. Our results suggest that even if the SR is incompletely preloaded with Ca2

Frontal Transcranial Direct Current Stimulation Induces Dopamine Release in the Ventral Striatum in Human

PubMed Central

Fonteneau, Clara; Redoute, Jérome; Haesebaert, Frédéric; Le Bars, Didier; Costes, Nicolas; Suaud-Chagny, Marie-Françoise; Brunelin, Jérome

2018-01-01

Abstract A single transcranial direct current stimulation (tDCS) session applied over the dorsolateral prefrontal cortex (DLFPC) can be associated with procognitive effects. Furthermore, repeated DLPFC tDCS sessions are under investigation as a new therapeutic tool for a range of neuropsychiatric conditions. A possible mechanism explaining such beneficial effects is a modulation of meso-cortico-limbic dopamine transmission. We explored the spatial and temporal neurobiological effects of bifrontal tDCS on subcortical dopamine transmission during and immediately after the stimulation. In a double blind sham-controlled study, 32 healthy subjects randomly received a single session of either active (20 min, 2 mA; n = 14) or sham (n = 18) tDCS during a dynamic positron emission tomography scan using [11C]raclopride binding. During the stimulation period, no significant effect of tDCS was observed. After the stimulation period, compared with sham tDCS, active tDCS induced a significant decrease in [11C]raclopride binding potential ratio in the striatum, suggesting an increase in extracellular dopamine in a part of the striatum involved in the reward–motivation network. The present study provides the first evidence that bifrontal tDCS induces neurotransmitter release in polysynaptic connected subcortical areas. Therefore, levels of dopamine activity and reactivity should be a new element to consider for a general hypothesis of brain modulation by bifrontal tDCS. PMID:29688276

Frontal Transcranial Direct Current Stimulation Induces Dopamine Release in the Ventral Striatum in Human.

PubMed

Fonteneau, Clara; Redoute, Jérome; Haesebaert, Frédéric; Le Bars, Didier; Costes, Nicolas; Suaud-Chagny, Marie-Françoise; Brunelin, Jérome

2018-07-01

A single transcranial direct current stimulation (tDCS) session applied over the dorsolateral prefrontal cortex (DLFPC) can be associated with procognitive effects. Furthermore, repeated DLPFC tDCS sessions are under investigation as a new therapeutic tool for a range of neuropsychiatric conditions. A possible mechanism explaining such beneficial effects is a modulation of meso-cortico-limbic dopamine transmission. We explored the spatial and temporal neurobiological effects of bifrontal tDCS on subcortical dopamine transmission during and immediately after the stimulation. In a double blind sham-controlled study, 32 healthy subjects randomly received a single session of either active (20 min, 2 mA; n = 14) or sham (n = 18) tDCS during a dynamic positron emission tomography scan using [11C]raclopride binding. During the stimulation period, no significant effect of tDCS was observed. After the stimulation period, compared with sham tDCS, active tDCS induced a significant decrease in [11C]raclopride binding potential ratio in the striatum, suggesting an increase in extracellular dopamine in a part of the striatum involved in the reward-motivation network. The present study provides the first evidence that bifrontal tDCS induces neurotransmitter release in polysynaptic connected subcortical areas. Therefore, levels of dopamine activity and reactivity should be a new element to consider for a general hypothesis of brain modulation by bifrontal tDCS.

An association between RBMX, a heterogeneous nuclear ribonucleoprotein, and ARTS-1 regulates extracellular TNFR1 release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamik, Barbara; Islam, Aminul; Rouhani, Farshid N.

The type I, 55-kDa tumor necrosis factor receptor (TNFR1) is released to the extracellular space by two mechanisms, the constitutive release of TNFR1 exosome-like vesicles and the inducible proteolytic cleavage of TNFR1 ectodomains. Both pathways appear to be regulated by an interaction between TNFR1 and ARTS-1 (aminopeptidase regulator of TNFR1 shedding). Here, we sought to identify ARTS-1-interacting proteins that modulate TNFR1 release. Co-immunoprecipitation identified an association between ARTS-1 and RBMX (RNA-binding motif gene, X chromosome), a 43-kDa heterogeneous nuclear ribonucleoprotein. RNA interference attenuated RBMX expression, which reduced both the constitutive release of TNFR1 exosome-like vesicles and the IL-1{beta}-mediated inducible proteolyticmore » cleavage of soluble TNFR1 ectodomains. Reciprocally, over-expression of RBMX increased TNFR1 exosome-like vesicle release and the IL-1{beta}-mediated inducible shedding of TNFR1 ectodomains. This identifies RBMX as an ARTS-1-associated protein that regulates both the constitutive release of TNFR1 exosome-like vesicles and the inducible proteolytic cleavage of TNFR1 ectodomains.« less

Cortisol Release in Response to UVB Exposure in Xiphophorus Fish

PubMed Central

Contreras, Adam J.; Boswell, Mikki; Downs, Kevin P.; Pasquali, Amanda; Walter, Ronald B.

2014-01-01

Xiphophorus fishes are comprised of 26 known species. Interspecies hybridization between select species has been utilized to produce experimental models to study melanoma development. Xiphophorus melanoma induction protocols utilize ultraviolet light (UVB) to induce DNA damage and associated downstream tumorigenesis. However, the impact of induced stress caused by the UVB treatment of the experimental animals undergoing tumor induction protocols has not been assessed. Stress is an adaptive physiological response to excessive or unpredictable environmental stimuli. The stress response in fishes may be measured by assay of cortisol released into the water. Here, we present results from investigations of stress response during experimental treatment and UVB exposure in X. maculatus Jp 163 B, X. couchianus, and F1 interspecies hybrids produced from the mating X. maculatus Jp 163 B x X. couchianus. Overall, cortisol release rates for males and females after UVB exposure showed no statistical differences. At lower UVB doses (8 and 16 kJ/m2), X. couchianus exhibited 2 fold higher levels of DNA damage then either X. maculatus or the F1 hybrid. However, based on cortisol release rates, none of the fish types tested induced a primary stress response at the UVB lower doses (8 and 16 kJ/m2). In contrast, at a very high UVB dose (32 kJ/m2) both X. maculatus and the F1 hybrid showed a 5 fold increase in cortisol release rate. To determine the effect of pigmentation on UVB induced stress, wild type and albino X. hellerii were exposed to UVB (32 kJ/m2). Albino X. hellerii exhibited 3.7 fold increase in cortisol release while wild type X. hellerii did not exhibit a significant cortisol response to UVB. Overall, the data suggest the rather low UVB doses often employed in tumour induction protocols do not induce a primary stress response in Xiphophorus fishes. PMID:24625568

Effects of dantrolene and its derivatives on Ca2+ release from the sarcoplasmic reticulum of mouse skeletal muscle fibres

PubMed Central

Ikemoto, Takaaki; Hosoya, Takamitsu; Aoyama, Hiroshi; Kihara, Yasutaka; Suzuki, Masaaki; Endo, Makoto

2001-01-01

We analysed the effect of dantrolene (Dan) and five newly synthesized derivatives (GIFs) on Ca2+ release from the sarcoplasmic reticulum (SR) of mouse skeletal muscle.In intact muscles, GIF-0185 reduced the size of twitch contraction induced by electrical stimulation to the same extent as Dan. GIF-0082, an azido-functionalized Dan derivative, also inhibited twitch contraction, although the extent of inhibition was less than that of Dan and of GIF-0185.In skinned fibres, Dan inhibited Ca2+-induced Ca2+ release (CICR) under Mg2+-free conditions at room temperature. In contrast, GIF-0082 and GIF-0185 showed no inhibitory effect on CICR under the same conditions.Dan-induced inhibition of CICR was not affected by the presence of GIF-0082, whereas it was diminished in the presence of GIF-0185.GIF-0082 and GIF-0185 significantly inhibited clofibric acid (Clof)-induced Ca2+ release, as did Dan.Several Dan derivatives other than GIF-0082 and GIF-0185 showed an inhibitory effect on twitch tension but not on the CICR mechanism. All of these derivatives inhibited Clof-induced Ca2+ release.The magnitudes of inhibition of Clof-induced Ca2+ release by all Dan derivatives were well correlated with those of twitch inhibition. This supports the notion that the mode of Clof-induced opening of the RyR-Ca2+ release channel may be similar to that of physiological Ca2+ release (PCR).These results indicate that the difference in opening modes of the RyR-Ca2+ release channel is recognized by certain Dan derivatives. PMID:11606312

Non-canonical Smads phosphorylation induced by the glutamate release inhibitor, riluzole, through GSK3 activation in melanoma.

PubMed

Abushahba, Walid; Olabisi, Oyenike O; Jeong, Byeong-Seon; Boregowda, Rajeev K; Wen, Yu; Liu, Fang; Goydos, James S; Lasfar, Ahmed; Cohen-Solal, Karine A

2012-01-01

Riluzole, an inhibitor of glutamate release, has shown the ability to inhibit melanoma cell xenograft growth. A phase 0 clinical trial of riluzole as a single agent in patients with melanoma resulted in involution of tumors associated with inhibition of both the mitogen-activated protein kinase (MAPK) and phophoinositide-3-kinase/AKT (PI3K/AKT) pathways in 34% of patients. In the present study, we demonstrate that riluzole inhibits AKT-mediated glycogen synthase kinase 3 (GSK3) phosphorylation in melanoma cell lines. Because we have demonstrated that GSK3 is involved in the phosphorylation of two downstream effectors of transforming growth factor beta (TGFβ), Smad2 and Smad3, at their linker domain, our aim was to determine whether riluzole could induce GSK3β-mediated linker phosphorylation of Smad2 and Smad3. We present evidence that riluzole increases Smad2 and Smad3 linker phosphorylation at the cluster of serines 245/250/255 and serine 204 respectively. Using GSK3 inhibitors and siRNA knock-down, we demonstrate that the mechanism of riluzole-induced Smad phosphorylation involved GSK3β. In addition, GSK3β could phosphorylate the same linker sites in vitro. The riluzole-induced Smad linker phosphorylation is mechanistically different from the Smad linker phosphorylation induced by TGFβ. We also demonstrate that riluzole-induced Smad linker phosphorylation is independent of the expression of the metabotropic glutamate receptor 1 (GRM1), which is one of the glutamate receptors whose involvement in human melanoma has been documented. We further show that riluzole upregulates the expression of INHBB and PLAU, two genes associated with the TGFβ signaling pathway. The non-canonical increase in Smad linker phosphorylation induced by riluzole could contribute to the modulation of the pro-oncogenic functions of Smads in late stage melanomas.

Non-Canonical Smads Phosphorylation Induced by the Glutamate Release Inhibitor, Riluzole, through GSK3 Activation in Melanoma

PubMed Central

Jeong, Byeong-Seon; Boregowda, Rajeev K.; Wen, Yu; Liu, Fang; Goydos, James S.; Lasfar, Ahmed; Cohen-Solal, Karine A.

2012-01-01

Riluzole, an inhibitor of glutamate release, has shown the ability to inhibit melanoma cell xenograft growth. A phase 0 clinical trial of riluzole as a single agent in patients with melanoma resulted in involution of tumors associated with inhibition of both the mitogen-activated protein kinase (MAPK) and phophoinositide-3-kinase/AKT (PI3K/AKT) pathways in 34% of patients. In the present study, we demonstrate that riluzole inhibits AKT-mediated glycogen synthase kinase 3 (GSK3) phosphorylation in melanoma cell lines. Because we have demonstrated that GSK3 is involved in the phosphorylation of two downstream effectors of transforming growth factor beta (TGFβ), Smad2 and Smad3, at their linker domain, our aim was to determine whether riluzole could induce GSK3β-mediated linker phosphorylation of Smad2 and Smad3. We present evidence that riluzole increases Smad2 and Smad3 linker phosphorylation at the cluster of serines 245/250/255 and serine 204 respectively. Using GSK3 inhibitors and siRNA knock-down, we demonstrate that the mechanism of riluzole-induced Smad phosphorylation involved GSK3β. In addition, GSK3β could phosphorylate the same linker sites in vitro. The riluzole-induced Smad linker phosphorylation is mechanistically different from the Smad linker phosphorylation induced by TGFβ. We also demonstrate that riluzole-induced Smad linker phosphorylation is independent of the expression of the metabotropic glutamate receptor 1 (GRM1), which is one of the glutamate receptors whose involvement in human melanoma has been documented. We further show that riluzole upregulates the expression of INHBB and PLAU, two genes associated with the TGFβ signaling pathway. The non-canonical increase in Smad linker phosphorylation induced by riluzole could contribute to the modulation of the pro-oncogenic functions of Smads in late stage melanomas. PMID:23077590

Polyoxometalate coordination induced controllable release of quinolone in hybrid film

NASA Astrophysics Data System (ADS)

Yang, Fan; Li, Yang; Lv, Yu-Guang; Zhou, Shu-Jing; Li, Si; Gao, Guang-Gang; Liu, Hong

2018-05-01

Due to some side effects of quinolones in vivo, it is an urgent issue to extend their new applications in vitro. In this paper, structure-determined vanadium-quinolone functionalized polymolybdates of (NH4)2 [(γ-Mo8O26){VO(CF)2}2] (1) and (NH4)2 [(γ-Mo8O26){VO(NF)2}2] (2) (CF = ciprofloxacin; NF = norfloxacin) have been designed and synthesized. Complex 1 or 2 features a γ-type [Mo8O26]4- polyanion functionalized by two monocapped vanadium-quinolone complexes. Different H-bonds and π···π interactions allow 1 or 2 to form a 2D layered structure at solid state. When complex 1 or 2 is transferred into polyvinyl alcohol (PVA) film, its release rate in solution is lower than that of CF- or NF-PVA film and thus forming a novel quinolone delivery system. This is the first time that slow release effect of quinolone is achieved by polyoxometalate coordination effect. The slow release of 1 or 2 in PVA film is mainly ascribed to the coordination of quinolone with polyoxometalate anions.

Gastrin-releasing peptide in human nasal mucosa.

PubMed

Baraniuk, J N; Lundgren, J D; Goff, J; Peden, D; Merida, M; Shelhamer, J; Kaliner, M

1990-04-01

Gastrin-releasing peptide (GRP), the 27 amino acid mammalian form of bombesin, was studied in human inferior turbinate nasal mucosa. The GRP content of the mucosa measured by radioimmunoassay was 0.60 +/- 0.25 pmol/g tissue (n = 9 patients; mean +/- SEM). GRP-immunoreactive nerves detected by the immunogold method of indirect immunohistochemistry were found predominantly in small muscular arteries, arterioles, venous sinusoids, and between submucosal gland acini. 125I-GRP binding sites determined by autoradiography were exclusively and specifically localized to nasal epithelium and submucosal glands. There was no binding to vessels. The effects of GRP on submucosal gland product release were studied in short-term explant culture. GRP (10 microM) significantly stimulated the release of the serous cell-specific product lactoferrin, and [3H]glucosamine-labeled glycoconjugates which are products of epithelial goblet cells and submucosal gland cells. These observations indicate that GRP released from nerve fibers probably acts on glandular GRP receptors to induce glycoconjugate release from submucosal glands and epithelium and lactoferrin release from serous cells, but that GRP would probably not affect vascular permeability.

Drug releasing nanoplatforms activated by alternating magnetic fields.

PubMed

Mertz, Damien; Sandre, Olivier; Bégin-Colin, Sylvie

2017-06-01

The use of an alternating magnetic field (AMF) to generate non-invasively and spatially a localized heating from a magnetic nano-mediator has become very popular these last years to develop magnetic hyperthermia (MH) as a promising therapeutic modality already used in the clinics. AMF has become highly attractive this last decade over others radiations, as AMF allows a deeper penetration in the body and a less harmful ionizing effect. In addition to pure MH which induces tumor cell death through local T elevation, this AMF-generated magneto-thermal effect can also be exploited as a relevant external stimulus to trigger a drug release from drug-loaded magnetic nanocarriers, temporally and spatially. This review article is focused especially on this concept of AMF induced drug release, possibly combined with MH. The design of such magnetically responsive drug delivery nanoplatforms requires two key and complementary components: a magnetic mediator which collects and turns the magnetic energy into local heat, and a thermoresponsive carrier ensuring thermo-induced drug release, as a consequence of magnetic stimulus. A wide panel of magnetic nanomaterials/chemistries and processes are currently developed to achieve such nanoplatforms. This review article presents a broad overview about the fundamental concepts of drug releasing nanoplatforms activated by AMF, their formulations, and their efficiency in vitro and in vivo. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editors: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader. Copyright © 2017 Elsevier B.V. All rights reserved.

Chronic nicotine administration differentially affects neurotransmitter release from rat striatal slices.

PubMed

Yu, Z J; Wecker, L

1994-07-01

The objective of these experiments was to determine whether the chronic administration of nicotine, at a dose regimen that increases the density of nicotine binding sites, alters the nicotine-induced release of [3H]-dopamine ([3H]DA), [3H]norepinephrine ([3H]NE), [3H]-serotonin ([3H]5-HT), or [3H]acetylcholine ([3H]ACh) from rat striatal slices. For these experiments, rats received subcutaneous injections of either saline or nicotine bitartrate [1.76 mg (3.6 mumol)/kg, dissolved in saline] twice daily for 10 days, and neurotransmitter release was measured following preloading of the tissues with [3H]DA, [3H]NE, [3H]5-HT, or [3H]choline. Chronic nicotine administration did not affect the accumulation of tritium by striatal slices, the basal release of radioactivity, or the 25 mM KCl-evoked release of neurotransmitter. Superfusion of striatal slices with 1, 10, and 100 microM nicotine increased [3H]DA release in a concentration-dependent manner, and release from slices from nicotine-injected animals was significantly (p < 0.05) greater than release from saline-injected controls; release from the former increased to 132, 191, and 172% of release from the controls following superfusion with 1, 10, and 100 microM nicotine, respectively. Similarly, [3H]5-HT release increased in a concentration-related manner following superfusion with nicotine, and release from slices from nicotine-injected rats was significantly (p < 0.05) greater than that from controls. [3H]5-HT release from slices from nicotine-injected rats evoked by superfusion with 1 and 10 microM nicotine increased to 453 and 217%, respectively, of release from slices from saline-injected animals. The nicotine-induced release of [3H]NE from striatal slices was also concentration dependent but was unaffected by chronic nicotine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Ibogaine alters synaptosomal and glial glutamate release and uptake.

PubMed

Leal, M B; Emanuelli, T; Porciúncula, L D; Souza, D O; Elisabetsky, E

2001-02-12

Ibogaine has aroused expectations as a potentially innovative medication for drug addiction. It has been proposed that antagonism of the NMDA receptor by ibogaine may be one of the mechanisms underlying its antiaddictive properties; glutamate has also been implicated in ibogaine-induced neurotoxicity. We here report the effects of ibogaine on [3H]glutamate release and uptake in cortical and cerebellar synaptosomes, as well as in cortical astrocyte cultures, from mice and rats. Ibogaine (2-1000 microM) had no effects on glutamate uptake or release by rat synaptosomes. However, ibogaine (500-1000 microM) significantly inhibited the glutamate uptake and stimulated the release of glutamate by cortical (but not cerebellar) synaptosomes of mice. In addition, ibogaine (1000 microM) nearly abolished glutamate uptake by cortical astrocyte cultures from rats and mice. The data provide direct evidence of glutamate involvement in ibogaine-induced neurotoxicity.

Piezo1 regulates mechanotransductive release of ATP from human RBCs.

PubMed

Cinar, Eyup; Zhou, Sitong; DeCourcey, James; Wang, Yixuan; Waugh, Richard E; Wan, Jiandi

2015-09-22

Piezo proteins (Piezo1 and Piezo2) are recently identified mechanically activated cation channels in eukaryotic cells and associated with physiological responses to touch, pressure, and stretch. In particular, human RBCs express Piezo1 on their membranes, and mutations of Piezo1 have been linked to hereditary xerocytosis. To date, however, physiological functions of Piezo1 on normal RBCs remain poorly understood. Here, we show that Piezo1 regulates mechanotransductive release of ATP from human RBCs by controlling the shear-induced calcium (Ca(2+)) influx. We find that, in human RBCs treated with Piezo1 inhibitors or having mutant Piezo1 channels, the amounts of shear-induced ATP release and Ca(2+) influx decrease significantly. Remarkably, a critical extracellular Ca(2+) concentration is required to trigger significant ATP release, but membrane-associated ATP pools in RBCs also contribute to the release of ATP. Our results show how Piezo1 channels are likely to function in normal RBCs and suggest a previously unidentified mechanotransductive pathway in ATP release. Thus, we anticipate that the study will impact broadly on the research of red cells, cellular mechanosensing, and clinical studies related to red cell disorders and vascular disease.

Dual regulation of Ca2+-dependent glutamate release from astrocytes: vesicular glutamate transporters and cytosolic glutamate levels.

PubMed

Ni, Yingchun; Parpura, Vladimir

2009-09-01

Vesicular glutamate transporters (VGLUTs) are responsible for vesicular glutamate storage and exocytotic glutamate release in neurons and astrocytes. Here, we selectively and efficiently overexpressed individual VGLUT proteins (VGLUT1, 2, or 3) in solitary astrocytes and studied their effects on mechanical stimulation-induced Ca2+-dependent glutamate release. Neither VGLUT1 nor VGLUT2 overexpression changed the amount of glutamate release, whereas overexpression of VGLUT3 significantly enhanced Ca2+-dependent glutamate release from astrocytes. None of the VGLUT overexpression affected mechanically induced intracellular Ca2+ increase. Inhibition of glutamine synthetase activity by L-methionine sulfoximine in astrocytes, which leads to increased cytosolic glutamate concentration, greatly increased their mechanically induced Ca2+-dependent glutamate release, without affecting intracellular Ca2+ dynamics. Taken together, these data indicate that both VGLUT3 and the cytosolic concentration of glutamate are key limiting factors in regulating the Ca2+-dependent release of glutamate from astrocytes.

6-Shogaol enhances renal carcinoma Caki cells to TRAIL-induced apoptosis through reactive oxygen species-mediated cytochrome c release and down-regulation of c-FLIP(L) expression.

PubMed

Han, Min Ae; Woo, Seon Min; Min, Kyoung-jin; Kim, Shin; Park, Jong-Wook; Kim, Dong Eun; Kim, Sang Hyun; Choi, Yung Hyun; Kwon, Taeg Kyu

2015-02-25

6-Shogaol, a potent bioactive compound in ginger (Zingiber officinale Roscoe), has been reported for anti-inflammatory and anti-cancer activity. In this study, we investigated the effect of 6-shogaol to enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. The combined treatment with 6-shogaol and TRAIL markedly induces apoptosis in various cancer cells (renal carcinoma Caki cells, breast carcinoma MDA-MB-231 cells and glioma U118MG cells), but not in normal mesangial cells and normal mouse kidney cells. 6-Shogaol reduced the mitochondrial membrane potential (MMP) and released cytochrome c from mitochondria to cytosol via Bax activation. Furthermore, we found that 6-shogaol induced down-regulation of c-FLIP(L) expression at the post-translational levels and the overexpression of c-FLIP(L) markedly inhibited 6-shogaol plus TRAIL-induced apoptosis. Moreover, 6-shogaol increased reactive oxygen species (ROS) production in Caki cells. Pretreatment with ROS scavengers attenuated 6-shogaol plus TRAIL-induced apoptosis through inhibition of MMP reduction and down-regulation of c-FLIP(L) expression. In addition, 6-gingerol, another phenolic alkanone isolated from ginger, did not enhance TRAIL-induced apoptosis and down-regulate c-FLIP(L) expression. Taken together, our results demonstrated that 6-shogaol enhances TRAIL-mediated apoptosis in renal carcinoma Caki cells via ROS-mediated cytochrome c release and down-regulation of c-FLIP(L) expression. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Fission fragment yields and total kinetic energy release in neutron-induced fission of235,238U,and239Pu

NASA Astrophysics Data System (ADS)

Tovesson, F.; Duke, D.; Geppert-Kleinrath, V.; Manning, B.; Mayorov, D.; Mosby, S.; Schmitt, K.

2018-03-01

Different aspects of the nuclear fission process have been studied at Los Alamos Neutron Science Center (LANSCE) using various instruments and experimental techniques. Properties of the fragments emitted in fission have been investigated using Frisch-grid ionization chambers, a Time Projection Chamber (TPC), and the SPIDER instrument which employs the 2v-2E method. These instruments and experimental techniques have been used to determine fission product mass yields, the energy dependent total kinetic energy (TKE) release, and anisotropy in neutron-induced fission of U-235, U-238 and Pu-239.

Effect of Engineered Nanoparticles on Exopolymeric Substances Release from Marine Phytoplankton.

PubMed

Chiu, Meng-Hsuen; Khan, Zafir A; Garcia, Santiago G; Le, Andre D; Kagiri, Agnes; Ramos, Javier; Tsai, Shih-Ming; Drobenaire, Hunter W; Santschi, Peter H; Quigg, Antonietta; Chin, Wei-Chun

2017-12-13

Engineered nanoparticles (ENPs), products from modern nanotechnologies, can potentially impact the marine environment to pose serious threats to marine ecosystems. However, the cellular responses of marine phytoplankton to ENPs are still not well established. Here, we investigate four different diatom species (Odontella mobiliensis, Skeletonema grethae, Phaeodactylum tricornutum, Thalassiosira pseudonana) and one green algae (Dunaliella tertiolecta) for their extracellular polymeric substances (EPS) release under model ENP treatments: 25 nm titanium dioxide (TiO 2 ), 10-20 nm silicon dioxide (SiO 2 ), and 15-30 nm cerium dioxide (CeO 2 ). We found SiO 2 ENPs can significantly stimulate EPS release from these algae (200-800%), while TiO 2 ENP exposure induced the lowest release. Furthermore, the increase of intracellular Ca 2+ concentration can be triggered by ENPs, suggesting that the EPS release process is mediated through Ca 2+ signal pathways. With better understanding of the cellular mechanism mediated ENP-induced EPS release, potential preventative and safety measures can be developed to mitigate negative impact on the marine ecosystem.

Effect of Engineered Nanoparticles on Exopolymeric Substances Release from Marine Phytoplankton

NASA Astrophysics Data System (ADS)

Chiu, Meng-Hsuen; Khan, Zafir A.; Garcia, Santiago G.; Le, Andre D.; Kagiri, Agnes; Ramos, Javier; Tsai, Shih-Ming; Drobenaire, Hunter W.; Santschi, Peter H.; Quigg, Antonietta; Chin, Wei-Chun

2017-12-01

Engineered nanoparticles (ENPs), products from modern nanotechnologies, can potentially impact the marine environment to pose serious threats to marine ecosystems. However, the cellular responses of marine phytoplankton to ENPs are still not well established. Here, we investigate four different diatom species ( Odontella mobiliensis, Skeletonema grethae, Phaeodactylum tricornutum, Thalassiosira pseudonana) and one green algae ( Dunaliella tertiolecta) for their extracellular polymeric substances (EPS) release under model ENP treatments: 25 nm titanium dioxide (TiO2), 10-20 nm silicon dioxide (SiO2), and 15-30 nm cerium dioxide (CeO2). We found SiO2 ENPs can significantly stimulate EPS release from these algae (200-800%), while TiO2 ENP exposure induced the lowest release. Furthermore, the increase of intracellular Ca2+ concentration can be triggered by ENPs, suggesting that the EPS release process is mediated through Ca2+ signal pathways. With better understanding of the cellular mechanism mediated ENP-induced EPS release, potential preventative and safety measures can be developed to mitigate negative impact on the marine ecosystem.

Multivesicular body formation enhancement and exosome release during endoplasmic reticulum stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanemoto, Soshi; Nitani, Ryota; Murakami, Tatsuhiko

The endoplasmic reticulum (ER) plays a pivotal role in maintaining cellular homeostasis. However, numerous environmental and genetic factors give rise to ER stress by inducing an accumulation of unfolded proteins. Under ER stress conditions, cells initiate the unfolded protein response (UPR). Here, we demonstrate a novel aspect of the UPR by electron microscopy and immunostaining analyses, whereby multivesicular body (MVB) formation was enhanced after ER stress. This MVB formation was influenced by inhibition of ER stress transducers inositol required enzyme 1 (IRE1) and PKR-like ER kinase (PERK). Furthermore, exosome release was also increased during ER stress. However, in IRE1 ormore » PERK deficient cells, exosome release was not upregulated, indicating that IRE1- and PERK-mediated pathways are involved in ER stress-dependent exosome release. - Highlights: • Endoplasmic reticulum (ER) stress induces multivesicular body (MVB) formation. • ER stress transducers IRE1 and PERK mediate MVB formation. • Exosome release is enhanced after ER stress. • IRE1 or PERK deficiency blocks upregulation of ER stress-dependent exosome release.« less

Effects of peritoneal fluid from endometriosis patients on interferon-gamma-induced protein-10 (CXCL10) and interleukin-8 (CXCL8) released by neutrophils and CD4+ T cells.

PubMed

Kim, Ji-Yeon; Lee, Dong-Hyung; Joo, Jong-Kil; Jin, Jun-O; Wang, Ji-Won; Hong, Young-Seoub; Kwak, Jong-Young; Lee, Kyu-Sup

2009-09-01

Intraperitoneal immuno-inflammatory changes may be associated with the pathogenesis of endometriosis. We evaluated the effects of peritoneal fluid obtained from patients with endometriosis (ePF) on the release of interferon-gamma-induced protein-10 (IP-10/CXCL10) and interleukin-8 (IL-8/CXCL8) by neutrophils, CD4(+) T cells, and monocytes. Neutrophils, CD4(+) T cells, and monocytes were cultured with ePF and the chemokine levels in the supernatants were then measured using enzyme-linked immunosorbent assay. The addition of ePF to cultures of CD4(+) T cells led to a significant increase in the release of IP-10 when compared with control PF without endometriosis (cPF). There was a positive correlation between the levels of IL-8 and IP-10 in ePF (R = 0.89, P = 0.041), but not between the levels of IP-10 and IL-8 released by neutrophils, CD4(+) T cells, and monocytes. The levels of IP-10 in ePF were positively correlated with the release of IP-10 by ePF-treated neutrophils (R = 0.89, P < 0.001), CD4(+) T cells (R = 0.93, P < 0.001), and monocytes (R = 0.70, P = 0.01). Moreover, the addition of ePF significantly enhanced the interferon-gamma-induced release of IP-10 by nuetrophils and CD4(+) T cells. These findings suggest that neutrophils and T cells release differential levels of IP-10 and IL-8 in response to stimulation with ePF, and that these cells are a major source of IP-10 in the PF of endometriosis patients.

Effects of conventional and hydrogen sulfide-releasing non-steroidal anti-inflammatory drugs in rats with stress-induced and epinephrine-induced gastric damage.

PubMed

Fomenko, Iryna; Sklyarov, Alexander; Bondarchuk, Tetyana; Biletska, Lilya; Panasyuk, Natalia; Wallace, John L

2014-12-01

Mechanisms of gastric defence under conditions of combined influence of acute stress and non-steroidal anti-inflammatory drugs (NSAIDs) are still poorly studied. The aim of this study was to explore the effects of different types of NSAIDs (naproxen, celecoxib and ATB-346) in producing experimental gastric lesions (induced by water-restraint stress (WRS) or by epinephrine (EPN) injection) and to determine the role of lipid peroxidation and the nitric oxide (NO) system in the pathogenesis of the damage. Male rats were used (eight per group) in this work. The NSAIDs were all administered at a dose 10 mg kg(-1) 30 min prior to WRS or EPN injection. Administration of naproxen to the control rats caused development of gastric lesions, whereas administration of a hydrogen sulfide (H2S)-releasing NSAID (ATB-346) or a selective cyclooxygenase-2 inhibitor (celecoxib) did not cause gastric damage. In contrast, lipid peroxidation processes were enhanced in all groups as was the activity of NO synthase (NOS). Pretreatment with naproxen in the WRS model caused an increase in severity of damage and a decrease in NOS activity. ATB-346 displayed beneficial effects, manifested by a decrease in the area of gastric damage, but parameters of lipid peroxidation and the NOS system did not differ substantially from those in the group treated with naproxen. Administration of different NSAIDs under conditions of EPN-induced gastric damage resulted in the decrease in NOS activity and lipid peroxidation. None of the tested NSAIDs exacerbated EPN-induced gastric mucosal injury; indeed, they all reduced the extent of damage.

Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release.

PubMed

Hedberg, Y; Wang, X; Hedberg, J; Lundin, M; Blomberg, E; Wallinder, I Odnevall

2013-04-01

Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

Histamine release inhibitory activity of Piper nigrum leaf.

PubMed

Hirata, Noriko; Naruto, Shunsuke; Inaba, Kazunori; Itoh, Kimihisa; Tokunaga, Masashi; Iinuma, Munekazu; Matsuda, Hideaki

2008-10-01

Oral administration of a methanolic extract of Piper nigrum leaf (PN-ext, 50, 200 and 500 mg/kg) showed a potent dose-dependent inhibition of dinitrofluorobenzene (DNFB)-induced cutaneous reaction at 1 h [immediate phase response (IPR)] after and 24 h [late phase response (LPR)] after DNFB challenge in mice which were passively sensitized with anti-dinitrophenyl (DNP) IgE antibody. Ear swelling inhibitory effect of PN-ext (50, 200 and 500 mg/kg, per os (p.o.)) on very late phase response (vLPR) in the model mice was significant but weaker than that on IPR. Oral administration of PN-ext (50, 200 and 500 mg/kg for 7 d) inhibited picryl chloride (PC)-induced ear swelling in PC sensitized mice. PN-ext exhibited in vitro inhibitory effect on compound 48/80-induced histamine release from rat peritoneal mast cells. Two lignans of PN-ext, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), were identified as major active principles having histamine release inhibitory activity.

Cortical Regulation of Striatal Medium Spiny Neuron Dendritic Remodeling in Parkinsonism: Modulation of Glutamate Release Reverses Dopamine Depletion–Induced Dendritic Spine Loss

PubMed Central

Garcia, Bonnie G.; Neely, M. Diana

2010-01-01

Striatal medium spiny neurons (MSNs) receive glutamatergic afferents from the cerebral cortex and dopaminergic inputs from the substantia nigra (SN). Striatal dopamine loss decreases the number of MSN dendritic spines. This loss of spines has been suggested to reflect the removal of tonic dopamine inhibitory control over corticostriatal glutamatergic drive, with increased glutamate release culminating in MSN spine loss. We tested this hypothesis in two ways. We first determined in vivo if decortication reverses or prevents dopamine depletion–induced spine loss by placing motor cortex lesions 4 weeks after, or at the time of, 6-hydroxydopamine lesions of the SN. Animals were sacrificed 4 weeks after cortical lesions. Motor cortex lesions significantly reversed the loss of MSN spines elicited by dopamine denervation; a similar effect was observed in the prevention experiment. We then determined if modulating glutamate release in organotypic cocultures prevented spine loss. Treatment of the cultures with the mGluR2/3 agonist LY379268 to suppress corticostriatal glutamate release completely blocked spine loss in dopamine-denervated cultures. These studies provide the first evidence to show that MSN spine loss associated with parkinsonism can be reversed and point to suppression of corticostriatal glutamate release as a means of slowing progression in Parkinson's disease. PMID:20118184

Leptin inhibits and ghrelin augments hypothalamic noradrenaline release after stress.

PubMed

Kawakami, Akio; Okada, Nobukazu; Rokkaku, Kumiko; Honda, Kazufumi; Ishibashi, Shun; Onaka, Tatsushi

2008-09-01

Metabolic conditions affect hypothalamo-pituitary-adrenal responses to stressful stimuli. Here we examined effects of food deprivation, leptin and ghrelin upon noradrenaline release in the hypothalamic paraventricular nucleus (PVN) and plasma adrenocorticotropic hormone (ACTH) concentrations after stressful stimuli. Food deprivation augmented both noradrenaline release in the PVN and the increase in plasma ACTH concentration following electrical footshocks (FSs). An intracerebroventricular injection of leptin attenuated the increases in hypothalamic noradrenaline release and plasma ACTH concentrations after FSs, while ghrelin augmented these responses. These data suggest that leptin inhibits and ghrelin facilitates neuroendocrine stress responses via noradrenaline release and indicate that a decrease in leptin and an increase in ghrelin release after food deprivation might contribute to augmentation of stress-induced ACTH release in a fasting state.

[The release of flavin adenine dinucleotide upon local conformational transition in electron-transferring flavoprotein induced by trimethylamine dehydrogenase].

PubMed

Lomtev, A S; Bobrov, A G; Vekshin, N L

2004-01-01

The electron-transferring proteins, trimethylamine dehydrogenase (TMAD) and electron-transferring flavoprotein (ETF) from the bacterium Methylophilius methylotrophus, were studied in vitro by fluorescence spectroscopy. Flavin adenine dinucleotide (FAD) was found to be capable of a slow and spontaneous release from ETF, which is accompanied by an increase in flavin fluorescence. At a rather high ionic strength (0.1 M NaCl or 50 mM phosphate), the FAD release is sharply activated by TMAD preparations that induce a local conformational transition in ETF. The values of tryptophan fluorescence polarization and lifetime and the use of the Levshin-Perrin equation helped show that the size of protein particles remain unchanged upon the TMAD and ETF mixing; i.e., these proteins themselves do not form a stable complex with each other. The protein mixture did not release flavin from ETF in the presence of trimethylamine and formaldehyde. In this case, a stable complex between the proteins appeared to be formed under the action of formaldehyde. Upon a short-term incubation of ETF with ferricyanide, FAD was hydrolyzed to flavin mononucleotide (FMN) and AMP. This fact explains the previous detection of AMP in ETF preparations by some researches. A fluorescence method was proposed for distinguishing FAD from FMN in solution using ethylene glycol. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

SiO2-induced release of sVEGFRs from pulmonary macrophages.

PubMed

Chao, Jie; Lv, Yan; Chen, Jin; Wang, Jing; Yao, Honghong

2018-01-01

The inhalation of silicon dioxide (SiO 2 ) particles causes silicosis, a stubborn pulmonary disease that is characterized by alveolar inflammation during the early stage. Soluble cytokine receptors (SCRs) play important roles in regulating inflammation by either attenuating or promoting cytokine signaling. However, the role of SCRs in silicosis remains unknown. Luminex assays revealed increased soluble vascular endothelial growth factor receptor (sVEGFR) family levels in the plasma of silicosis patients. In an enzyme-linked immunosorbent assay (ELISA), cells from the differentiated human monocytic cell line U937 released sVEGFR family proteins after exposure to SiO 2 (50μg/cm 2 ). Further Western blot experiments revealed that VEGFR expression was also elevated in U937 cells. In contrast, levels of sVEGFR family members did not change in the supernatants of human umbilical vein endothelial cells (HUVECs) after exposure to SiO 2 (50μg/cm 2 ). Interestingly, VEGFR expression in HUVECs decreased after SiO 2 treatment. In a scratch assay, HUVECs exhibited cell migration ability, indicating the acquisition of mesenchymal properties. Our findings highlight the important role of sVEGFRs in both inflammation and fibrosis induced by SiO 2 , suggesting a possible mechanism for the fibrogenic effects observed in pulmonary diseases associated with fibrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

C-terminal substance P fragments elicit histamine release from a murine mast cell line.

PubMed

Krumins, S A; Broomfield, C A

1993-01-01

Incubation of mouse mast cells with C-terminal substance P fragments in the micromolar range caused a release of histamine. Maximum release was observed with the tetrapeptide SP(8-11), followed by the tripeptide SP(9-11). SP(6-11) and SP(5-11) were nearly equipotent, while SP(4-11) caused only a slight histamine release. The substance P parent molecule and the N-terminal substance P fragments SP(1-4), SP(1-6) and SP(1-7) evoked no release of histamine. In confirmation of our previous findings, incubation with neurokinin A caused a release comparable to that of SP(8-11). Whereas neurokinin A-induced release was partially preventable by pretreating the cells with the NK2 receptor-selective antagonist cyclo(Gln-Trp-Phe-(R)Gly[ANC-2]Leu-Met), SP(8-11)-induced release was completely abolished by such treatment. The results provide the first evidence for the involvement of NK2 tachykinin receptors in the release of histamine by C-terminal substance P fragments.